As of Linux 4.17, there are more than 30000 exported symbols
in the kernel. There seems to be some consensus amongst
kernel devs that the export surface is too large, and hard
to reason about.
Generally, these symbols fall in one of these categories:
1) Symbols actually meant for drivers
2) Symbols that are only exported because functionality is
split over multiple modules, yet they really shouldn't
be used by modules outside of their own subsystem
3) Symbols really only meant for in-tree use
When module developers try to upstream their code, it
regularly turns out that they are using exported symbols
that they really shouldn't be using. This problem is even
bigger for drivers that are currently out-of-tree, which
may be using many symbols that they shouldn't be using,
and that break when those symbols are removed or modified.
This patch allows subsystem maintainers to partition their
exported symbols into separate namespaces, and module
authors to import such namespaces only when needed.
This allows subsystem maintainers to more easily limit
availability of these namespaced symbols to other parts of
the kernel. It can also be used to partition the set of
exported symbols for documentation purposes; for example,
a set of symbols that is really only used for debugging
could be in a "SUBSYSTEM_DEBUG" namespace.
Martijn Coenen (6):
export: explicitly align struct kernel_symbol.
module: add support for symbol namespaces.
modpost: add support for checking symbol namespaces.
modpost: add support for generating namespace dependencies.
scripts: Coccinelle script for namespace dependencies.
RFC: USB: storage: move symbols into USB_STORAGE namespace.
Makefile | 11 +++
arch/m68k/include/asm/export.h | 1 -
arch/x86/include/asm/Kbuild | 1 +
arch/x86/include/asm/export.h | 5 --
drivers/usb/storage/alauda.c | 1 +
drivers/usb/storage/cypress_atacb.c | 1 +
drivers/usb/storage/datafab.c | 1 +
drivers/usb/storage/ene_ub6250.c | 1 +
drivers/usb/storage/freecom.c | 1 +
drivers/usb/storage/isd200.c | 1 +
drivers/usb/storage/jumpshot.c | 1 +
drivers/usb/storage/karma.c | 1 +
drivers/usb/storage/onetouch.c | 1 +
drivers/usb/storage/realtek_cr.c | 1 +
drivers/usb/storage/sddr09.c | 1 +
drivers/usb/storage/sddr55.c | 1 +
drivers/usb/storage/shuttle_usbat.c | 1 +
drivers/usb/storage/uas.c | 1 +
drivers/usb/storage/usb.c | 20 ++---
include/asm-generic/export.h | 2 +-
include/linux/export.h | 84 ++++++++++++++-----
include/linux/module.h | 13 +++
kernel/module.c | 79 ++++++++++++++++++
scripts/Makefile.modpost | 4 +-
scripts/add_namespace.cocci | 19 +++++
scripts/mod/modpost.c | 120 ++++++++++++++++++++++++++--
scripts/mod/modpost.h | 9 +++
scripts/nsdeps | 41 ++++++++++
28 files changed, 379 insertions(+), 44 deletions(-)
delete mode 100644 arch/x86/include/asm/export.h
create mode 100644 scripts/add_namespace.cocci
create mode 100644 scripts/nsdeps
--
2.18.0.203.gfac676dfb9-goog
Modules using these symbols must now import this namesapce explicitly.
Signed-off-by: Martijn Coenen <[email protected]>
---
drivers/usb/storage/alauda.c | 1 +
drivers/usb/storage/cypress_atacb.c | 1 +
drivers/usb/storage/datafab.c | 1 +
drivers/usb/storage/ene_ub6250.c | 1 +
drivers/usb/storage/freecom.c | 1 +
drivers/usb/storage/isd200.c | 1 +
drivers/usb/storage/jumpshot.c | 1 +
drivers/usb/storage/karma.c | 1 +
drivers/usb/storage/onetouch.c | 1 +
drivers/usb/storage/realtek_cr.c | 1 +
drivers/usb/storage/sddr09.c | 1 +
drivers/usb/storage/sddr55.c | 1 +
drivers/usb/storage/shuttle_usbat.c | 1 +
drivers/usb/storage/uas.c | 1 +
drivers/usb/storage/usb.c | 20 ++++++++++----------
15 files changed, 24 insertions(+), 10 deletions(-)
diff --git a/drivers/usb/storage/alauda.c b/drivers/usb/storage/alauda.c
index 6b8edf6178df..ddab2cd3d2e7 100644
--- a/drivers/usb/storage/alauda.c
+++ b/drivers/usb/storage/alauda.c
@@ -36,6 +36,7 @@
MODULE_DESCRIPTION("Driver for Alauda-based card readers");
MODULE_AUTHOR("Daniel Drake <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
/*
* Status bytes
diff --git a/drivers/usb/storage/cypress_atacb.c b/drivers/usb/storage/cypress_atacb.c
index 4825902377eb..a6f3267bbef6 100644
--- a/drivers/usb/storage/cypress_atacb.c
+++ b/drivers/usb/storage/cypress_atacb.c
@@ -22,6 +22,7 @@
MODULE_DESCRIPTION("SAT support for Cypress USB/ATA bridges with ATACB");
MODULE_AUTHOR("Matthieu Castet <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
/*
* The table of devices
diff --git a/drivers/usb/storage/datafab.c b/drivers/usb/storage/datafab.c
index 09353be199be..588818483f4b 100644
--- a/drivers/usb/storage/datafab.c
+++ b/drivers/usb/storage/datafab.c
@@ -54,6 +54,7 @@
MODULE_DESCRIPTION("Driver for Datafab USB Compact Flash reader");
MODULE_AUTHOR("Jimmie Mayfield <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
struct datafab_info {
unsigned long sectors; /* total sector count */
diff --git a/drivers/usb/storage/ene_ub6250.c b/drivers/usb/storage/ene_ub6250.c
index 4d261e4de9ad..57e782a62acd 100644
--- a/drivers/usb/storage/ene_ub6250.c
+++ b/drivers/usb/storage/ene_ub6250.c
@@ -26,6 +26,7 @@
MODULE_DESCRIPTION("Driver for ENE UB6250 reader");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
MODULE_FIRMWARE(SD_INIT1_FIRMWARE);
MODULE_FIRMWARE(SD_INIT2_FIRMWARE);
MODULE_FIRMWARE(SD_RW_FIRMWARE);
diff --git a/drivers/usb/storage/freecom.c b/drivers/usb/storage/freecom.c
index 4f542df37a44..34e7eaff1174 100644
--- a/drivers/usb/storage/freecom.c
+++ b/drivers/usb/storage/freecom.c
@@ -29,6 +29,7 @@
MODULE_DESCRIPTION("Driver for Freecom USB/IDE adaptor");
MODULE_AUTHOR("David Brown <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
#ifdef CONFIG_USB_STORAGE_DEBUG
static void pdump(struct us_data *us, void *ibuffer, int length);
diff --git a/drivers/usb/storage/isd200.c b/drivers/usb/storage/isd200.c
index f5e4500d9970..7abb5687b2f6 100644
--- a/drivers/usb/storage/isd200.c
+++ b/drivers/usb/storage/isd200.c
@@ -53,6 +53,7 @@
MODULE_DESCRIPTION("Driver for In-System Design, Inc. ISD200 ASIC");
MODULE_AUTHOR("Björn Stenberg <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
static int isd200_Initialization(struct us_data *us);
diff --git a/drivers/usb/storage/jumpshot.c b/drivers/usb/storage/jumpshot.c
index 917f170c4124..229bf0c1afc9 100644
--- a/drivers/usb/storage/jumpshot.c
+++ b/drivers/usb/storage/jumpshot.c
@@ -51,6 +51,7 @@
MODULE_DESCRIPTION("Driver for Lexar \"Jumpshot\" Compact Flash reader");
MODULE_AUTHOR("Jimmie Mayfield <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
/*
* The table of devices
diff --git a/drivers/usb/storage/karma.c b/drivers/usb/storage/karma.c
index edcf2be0e0eb..2b6e74afdcbd 100644
--- a/drivers/usb/storage/karma.c
+++ b/drivers/usb/storage/karma.c
@@ -23,6 +23,7 @@
MODULE_DESCRIPTION("Driver for Rio Karma");
MODULE_AUTHOR("Bob Copeland <[email protected]>, Keith Bennett <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
#define RIO_PREFIX "RIOP\x00"
#define RIO_PREFIX_LEN 5
diff --git a/drivers/usb/storage/onetouch.c b/drivers/usb/storage/onetouch.c
index 39a5009a41a6..a989fe930e21 100644
--- a/drivers/usb/storage/onetouch.c
+++ b/drivers/usb/storage/onetouch.c
@@ -25,6 +25,7 @@
MODULE_DESCRIPTION("Maxtor USB OneTouch hard drive button driver");
MODULE_AUTHOR("Nick Sillik <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
#define ONETOUCH_PKT_LEN 0x02
#define ONETOUCH_BUTTON KEY_PROG1
diff --git a/drivers/usb/storage/realtek_cr.c b/drivers/usb/storage/realtek_cr.c
index 31b024441938..96c45fee687a 100644
--- a/drivers/usb/storage/realtek_cr.c
+++ b/drivers/usb/storage/realtek_cr.c
@@ -35,6 +35,7 @@
MODULE_DESCRIPTION("Driver for Realtek USB Card Reader");
MODULE_AUTHOR("wwang <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
static int auto_delink_en = 1;
module_param(auto_delink_en, int, S_IRUGO | S_IWUSR);
diff --git a/drivers/usb/storage/sddr09.c b/drivers/usb/storage/sddr09.c
index bc9da736bdfc..51bcd4a43690 100644
--- a/drivers/usb/storage/sddr09.c
+++ b/drivers/usb/storage/sddr09.c
@@ -47,6 +47,7 @@
MODULE_DESCRIPTION("Driver for SanDisk SDDR-09 SmartMedia reader");
MODULE_AUTHOR("Andries Brouwer <[email protected]>, Robert Baruch <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
static int usb_stor_sddr09_dpcm_init(struct us_data *us);
static int sddr09_transport(struct scsi_cmnd *srb, struct us_data *us);
diff --git a/drivers/usb/storage/sddr55.c b/drivers/usb/storage/sddr55.c
index b8527c55335b..ba955d65eb0e 100644
--- a/drivers/usb/storage/sddr55.c
+++ b/drivers/usb/storage/sddr55.c
@@ -29,6 +29,7 @@
MODULE_DESCRIPTION("Driver for SanDisk SDDR-55 SmartMedia reader");
MODULE_AUTHOR("Simon Munton");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
/*
* The table of devices
diff --git a/drivers/usb/storage/shuttle_usbat.c b/drivers/usb/storage/shuttle_usbat.c
index 854498e1012c..54aa1392c9ca 100644
--- a/drivers/usb/storage/shuttle_usbat.c
+++ b/drivers/usb/storage/shuttle_usbat.c
@@ -48,6 +48,7 @@
MODULE_DESCRIPTION("Driver for SCM Microsystems (a.k.a. Shuttle) USB-ATAPI cable");
MODULE_AUTHOR("Daniel Drake <[email protected]>, Robert Baruch <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
/* Supported device types */
#define USBAT_DEV_HP8200 0x01
diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
index 9e9de5452860..0a9b20478ee9 100644
--- a/drivers/usb/storage/uas.c
+++ b/drivers/usb/storage/uas.c
@@ -1195,5 +1195,6 @@ static struct usb_driver uas_driver = {
module_usb_driver(uas_driver);
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
MODULE_AUTHOR(
"Hans de Goede <[email protected]>, Matthew Wilcox and Sarah Sharp");
diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c
index 9a79cd9762f3..fd5adc4e95d8 100644
--- a/drivers/usb/storage/usb.c
+++ b/drivers/usb/storage/usb.c
@@ -184,7 +184,7 @@ int usb_stor_suspend(struct usb_interface *iface, pm_message_t message)
mutex_unlock(&us->dev_mutex);
return 0;
}
-EXPORT_SYMBOL_GPL(usb_stor_suspend);
+EXPORT_SYMBOL_NS_GPL(usb_stor_suspend, USB_STORAGE);
int usb_stor_resume(struct usb_interface *iface)
{
@@ -198,7 +198,7 @@ int usb_stor_resume(struct usb_interface *iface)
mutex_unlock(&us->dev_mutex);
return 0;
}
-EXPORT_SYMBOL_GPL(usb_stor_resume);
+EXPORT_SYMBOL_NS_GPL(usb_stor_resume, USB_STORAGE);
int usb_stor_reset_resume(struct usb_interface *iface)
{
@@ -213,7 +213,7 @@ int usb_stor_reset_resume(struct usb_interface *iface)
*/
return 0;
}
-EXPORT_SYMBOL_GPL(usb_stor_reset_resume);
+EXPORT_SYMBOL_NS_GPL(usb_stor_reset_resume, USB_STORAGE);
#endif /* CONFIG_PM */
@@ -230,7 +230,7 @@ int usb_stor_pre_reset(struct usb_interface *iface)
mutex_lock(&us->dev_mutex);
return 0;
}
-EXPORT_SYMBOL_GPL(usb_stor_pre_reset);
+EXPORT_SYMBOL_NS_GPL(usb_stor_pre_reset, USB_STORAGE);
int usb_stor_post_reset(struct usb_interface *iface)
{
@@ -247,7 +247,7 @@ int usb_stor_post_reset(struct usb_interface *iface)
mutex_unlock(&us->dev_mutex);
return 0;
}
-EXPORT_SYMBOL_GPL(usb_stor_post_reset);
+EXPORT_SYMBOL_NS_GPL(usb_stor_post_reset, USB_STORAGE);
/*
* fill_inquiry_response takes an unsigned char array (which must
@@ -293,7 +293,7 @@ void fill_inquiry_response(struct us_data *us, unsigned char *data,
usb_stor_set_xfer_buf(data, data_len, us->srb);
}
-EXPORT_SYMBOL_GPL(fill_inquiry_response);
+EXPORT_SYMBOL_NS_GPL(fill_inquiry_response, USB_STORAGE);
static int usb_stor_control_thread(void * __us)
{
@@ -579,7 +579,7 @@ void usb_stor_adjust_quirks(struct usb_device *udev, unsigned long *fflags)
}
*fflags = (*fflags & ~mask) | f;
}
-EXPORT_SYMBOL_GPL(usb_stor_adjust_quirks);
+EXPORT_SYMBOL_NS_GPL(usb_stor_adjust_quirks, USB_STORAGE);
/* Get the unusual_devs entries and the string descriptors */
static int get_device_info(struct us_data *us, const struct usb_device_id *id,
@@ -990,7 +990,7 @@ int usb_stor_probe1(struct us_data **pus,
release_everything(us);
return result;
}
-EXPORT_SYMBOL_GPL(usb_stor_probe1);
+EXPORT_SYMBOL_NS_GPL(usb_stor_probe1, USB_STORAGE);
/* Second part of general USB mass-storage probing */
int usb_stor_probe2(struct us_data *us)
@@ -1074,7 +1074,7 @@ int usb_stor_probe2(struct us_data *us)
release_everything(us);
return result;
}
-EXPORT_SYMBOL_GPL(usb_stor_probe2);
+EXPORT_SYMBOL_NS_GPL(usb_stor_probe2, USB_STORAGE);
/* Handle a USB mass-storage disconnect */
void usb_stor_disconnect(struct usb_interface *intf)
@@ -1084,7 +1084,7 @@ void usb_stor_disconnect(struct usb_interface *intf)
quiesce_and_remove_host(us);
release_everything(us);
}
-EXPORT_SYMBOL_GPL(usb_stor_disconnect);
+EXPORT_SYMBOL_NS_GPL(usb_stor_disconnect, USB_STORAGE);
static struct scsi_host_template usb_stor_host_template;
--
2.18.0.203.gfac676dfb9-goog
A script that uses the '<module>.ns_deps' file generated by modpost to
automatically add the required symbol namespace dependencies to each
module.
Usage:
1) Move some symbols to a namespace with EXPORT_SYMBOL_NS()
2) Run 'make' (or 'make modules'), get warnings about modules not
importing that namespace
3) Run 'make nsdeps' to automatically add required import statements
to said modules
This makes it easer for subsystem maintainers to introduce and maintain
symbol namespaces into their codebase.
Signed-off-by: Martijn Coenen <[email protected]>
---
Makefile | 11 ++++++++++
scripts/Makefile.modpost | 4 +++-
scripts/add_namespace.cocci | 19 +++++++++++++++++
scripts/nsdeps | 41 +++++++++++++++++++++++++++++++++++++
4 files changed, 74 insertions(+), 1 deletion(-)
create mode 100644 scripts/add_namespace.cocci
create mode 100644 scripts/nsdeps
diff --git a/Makefile b/Makefile
index 925c55f2524f..96e62d732a3b 100644
--- a/Makefile
+++ b/Makefile
@@ -1391,6 +1391,9 @@ help:
@echo ' headerdep - Detect inclusion cycles in headers'
@echo ' coccicheck - Check with Coccinelle'
@echo ''
+ @echo 'Tools:'
+ @echo ' nsdeps - Generate missing symbol namespace dependencies'
+ @echo ''
@echo 'Kernel selftest:'
@echo ' kselftest - Build and run kernel selftest (run as root)'
@echo ' Build, install, and boot kernel before'
@@ -1566,6 +1569,14 @@ quiet_cmd_tags = GEN $@
tags TAGS cscope gtags: FORCE
$(call cmd,tags)
+# Script to generate missing namespace dependencies
+
+PHONY += nsdeps
+
+nsdeps:
+ $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost nsdeps
+ $(Q)$(CONFIG_SHELL) $(srctree)/scripts/$@
+
# Scripts to check various things for consistency
# ---------------------------------------------------------------------------
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index df4174405feb..a9a90c3e3879 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -79,7 +79,8 @@ modpost = scripts/mod/modpost \
$(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \
$(if $(CONFIG_DEBUG_SECTION_MISMATCH),,-S) \
$(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \
- $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w)
+ $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w) \
+ $(if $(filter nsdeps,$(MAKECMDGOALS)),-d)
MODPOST_OPT=$(subst -i,-n,$(filter -i,$(MAKEFLAGS)))
@@ -130,6 +131,7 @@ $(modules): %.ko :%.o %.mod.o FORCE
targets += $(modules)
+nsdeps: _modpost
# Add FORCE to the prequisites of a target to force it to be always rebuilt.
# ---------------------------------------------------------------------------
diff --git a/scripts/add_namespace.cocci b/scripts/add_namespace.cocci
new file mode 100644
index 000000000000..a6d33e066067
--- /dev/null
+++ b/scripts/add_namespace.cocci
@@ -0,0 +1,19 @@
+@has_ns_import@
+declarer name MODULE_IMPORT_NS;
+identifier virtual.ns;
+@@
+MODULE_IMPORT_NS(ns);
+
+@has_module_license@
+declarer name MODULE_LICENSE;
+expression license;
+@@
+MODULE_LICENSE(license);
+
+@do_import depends on has_module_license && !has_ns_import@
+declarer name MODULE_LICENSE;
+expression license;
+identifier virtual.ns;
+@@
+MODULE_LICENSE(license);
++ MODULE_IMPORT_NS(ns);
diff --git a/scripts/nsdeps b/scripts/nsdeps
new file mode 100644
index 000000000000..5678e02626b3
--- /dev/null
+++ b/scripts/nsdeps
@@ -0,0 +1,41 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Linux kernel symbol namespace import generator
+#
+# This script requires at least spatch
+# version 1.0.6.
+SPATCH_REQ_VERSION="1.0.6"
+
+DIR="$(dirname $(readlink -f $0))/.."
+SPATCH="`which ${SPATCH:=spatch}`"
+if [ ! -x "$SPATCH" ]; then
+ echo 'spatch is part of the Coccinelle project and is available at http://coccinelle.lip6.fr/'
+ exit 1
+fi
+
+SPATCH_REQ_VERSION_NUM=$(echo $SPATCH_REQ_VERSION | ${DIR}/scripts/ld-version.sh)
+SPATCH_VERSION=$($SPATCH --version | head -1 | awk '{print $3}')
+SPATCH_VERSION_NUM=$(echo $SPATCH_VERSION | ${DIR}/scripts/ld-version.sh)
+
+if [ "$SPATCH_VERSION_NUM" -lt "$SPATCH_REQ_VERSION_NUM" ] ; then
+ echo 'spatch needs to be version 1.06 or higher'
+ exit 1
+fi
+
+generate_deps_for_ns() {
+ $SPATCH --very-quiet --in-place --sp-file $srctree/scripts/add_namespace.cocci -D ns=$1 $2
+}
+
+generate_deps() {
+ local mod_file=`echo $@ | sed -e 's/\.ns_deps/\.mod/'`
+ local mod_name=`cat $mod_file | sed -n 1p | sed -e 's/\/[^.]*$//'`
+ local mod_source_files=`cat $mod_file | sed -n 2p | sed -e 's/\.o/\.c/'`
+ for ns in `cat $@`; do
+ echo "Adding namespace $ns to module $mod_name (if needed)."
+ generate_deps_for_ns $ns $mod_source_files
+ done
+}
+
+for f in `find $srctree/.tmp_versions/ -name *.ns_deps`; do
+ generate_deps $f
+done
--
2.18.0.203.gfac676dfb9-goog
This patch adds an option to modpost to generate a .ns_deps file per
module, containing the namespace depedencies for that module.
This file can subsequently be used by other tools to automatically add
newly introduced namespaces to the modules that require them, saving a
lot of manual work.
Signed-off-by: Martijn Coenen <[email protected]>
---
scripts/mod/modpost.c | 58 +++++++++++++++++++++++++++++++++++++++----
scripts/mod/modpost.h | 2 ++
2 files changed, 55 insertions(+), 5 deletions(-)
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index a56a8461a96a..be33d60d5527 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -39,6 +39,8 @@ static int sec_mismatch_verbose = 1;
static int sec_mismatch_fatal = 0;
/* ignore missing files */
static int ignore_missing_files;
+/* Write namespace dependencies */
+static int write_ns_deps;
enum export {
export_plain, export_unused, export_gpl,
@@ -2151,10 +2153,15 @@ static void check_exports(struct module *mod)
else
basename = mod->name;
- if (exp->ns && !module_imports_namespace(mod, exp->ns)) {
- warn("module %s uses symbol %s from namespace %s, "
- "but does not import it.\n",
- basename, exp->name, exp->ns);
+ if (exp->ns) {
+ add_namespace(&mod->required_namespaces, exp->ns);
+
+ if (!write_ns_deps &&
+ !module_imports_namespace(mod, exp->ns)) {
+ warn("module %s uses symbol %s from namespace "
+ "%s, but does not import it.\n",
+ basename, exp->name, exp->ns);
+ }
}
if (!mod->gpl_compatible)
@@ -2457,6 +2464,38 @@ static void write_dump(const char *fname)
free(buf.p);
}
+static void write_ns_deps_files(void)
+{
+ struct module *mod;
+ struct namespace_list *ns;
+ struct buffer ns_deps_buf = { };
+
+ for (mod = modules; mod; mod = mod->next) {
+ char fname[PATH_MAX];
+ const char *basename;
+
+ if (mod->skip)
+ continue;
+
+ ns_deps_buf.pos = 0;
+
+ for (ns = mod->required_namespaces; ns; ns = ns->next)
+ buf_printf(&ns_deps_buf, "%s\n", ns->namespace);
+
+ if (ns_deps_buf.pos == 0)
+ continue;
+
+ basename = strrchr(mod->name, '/');
+ if (basename)
+ basename++;
+ else
+ basename = mod->name;
+
+ sprintf(fname, ".tmp_versions/%s.ns_deps", basename);
+ write_if_changed(&ns_deps_buf, fname);
+ }
+}
+
struct ext_sym_list {
struct ext_sym_list *next;
const char *file;
@@ -2473,7 +2512,7 @@ int main(int argc, char **argv)
struct ext_sym_list *extsym_iter;
struct ext_sym_list *extsym_start = NULL;
- while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) {
+ while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:Ed")) != -1) {
switch (opt) {
case 'i':
kernel_read = optarg;
@@ -2517,6 +2556,9 @@ int main(int argc, char **argv)
case 'E':
sec_mismatch_fatal = 1;
break;
+ case 'd':
+ write_ns_deps = 1;
+ break;
default:
exit(1);
}
@@ -2545,6 +2587,12 @@ int main(int argc, char **argv)
check_exports(mod);
}
+ if (write_ns_deps) {
+ /* Just write namespace dependencies and exit */
+ write_ns_deps_files();
+ return 0;
+ }
+
err = 0;
for (mod = modules; mod; mod = mod->next) {
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index 9626bf3e7424..92a926d375d2 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -126,6 +126,8 @@ struct module {
struct buffer dev_table_buf;
char srcversion[25];
int is_dot_o;
+ // Required namespace dependencies
+ struct namespace_list *required_namespaces;
// Actual imported namespaces
struct namespace_list *imported_namespaces;
};
--
2.18.0.203.gfac676dfb9-goog
Emits a warning whenever a module refers to an exported symbol without
explicitly importing the namespace that it is defined in.
Example:
WARNING: module ums-usbat uses symbol usb_stor_resume from namespace
USB_STORAGE_NS, but does not import it.
Signed-off-by: Martijn Coenen <[email protected]>
---
scripts/mod/modpost.c | 70 +++++++++++++++++++++++++++++++++++++++----
scripts/mod/modpost.h | 7 +++++
2 files changed, 72 insertions(+), 5 deletions(-)
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 1663fb19343a..a56a8461a96a 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -165,6 +165,7 @@ struct symbol {
struct module *module;
unsigned int crc;
int crc_valid;
+ const char *ns; /* namespace */
unsigned int weak:1;
unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
unsigned int kernel:1; /* 1 if symbol is from kernel
@@ -234,6 +235,35 @@ static struct symbol *find_symbol(const char *name)
return NULL;
}
+static bool contains_namespace(struct namespace_list *list, const char *ns)
+{
+ struct namespace_list *ns_entry;
+
+ for (ns_entry = list; ns_entry != NULL; ns_entry = ns_entry->next) {
+ if (strcmp(ns_entry->namespace, ns) == 0)
+ return true;
+ }
+
+ return false;
+}
+
+static void add_namespace(struct namespace_list **list, const char *ns)
+{
+ struct namespace_list *ns_entry;
+
+ if (!contains_namespace(*list, ns)) {
+ ns_entry = NOFAIL(malloc(sizeof(struct namespace_list)));
+ strcpy(ns_entry->namespace, ns);
+ ns_entry->next = *list;
+ *list = ns_entry;
+ }
+}
+
+static bool module_imports_namespace(struct module *module, const char *ns)
+{
+ return contains_namespace(module->imported_namespaces, ns);
+}
+
static const struct {
const char *str;
enum export export;
@@ -313,21 +343,40 @@ static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
return export_unknown;
}
+static const char *sym_extract_ns(const char **symname)
+{
+ size_t n;
+
+ n = strcspn(*symname, ".");
+ if (n < strlen(*symname) - 1) {
+ char *dupsymname = NOFAIL(strdup(*symname));
+
+ dupsymname[n] = '\0';
+ *symname = dupsymname;
+ return dupsymname + n + 1;
+ } else {
+ return NULL;
+ }
+}
+
/**
* Add an exported symbol - it may have already been added without a
* CRC, in this case just update the CRC
**/
-static struct symbol *sym_add_exported(const char *name, struct module *mod,
- enum export export)
+static struct symbol *sym_add_exported(const char *name,
+ struct module *mod, enum export export)
{
- struct symbol *s = find_symbol(name);
+ const char *extract_name = name;
+ const char *ns = sym_extract_ns(&extract_name);
+ struct symbol *s = find_symbol(extract_name);
if (!s) {
- s = new_symbol(name, mod, export);
+ s = new_symbol(extract_name, mod, export);
+ s->ns = ns;
} else {
if (!s->preloaded) {
warn("%s: '%s' exported twice. Previous export "
- "was in %s%s\n", mod->name, name,
+ "was in %s%s\n", mod->name, extract_name,
s->module->name,
is_vmlinux(s->module->name) ?"":".ko");
} else {
@@ -697,6 +746,10 @@ static void handle_modversions(struct module *mod, struct elf_info *info,
}
if (strcmp(symname, "init_module") == 0)
mod->has_init = 1;
+ if (strstarts(symname, "__knsimport_")) {
+ const char *name = symname + strlen("__knsimport_");
+ add_namespace(&mod->imported_namespaces, name);
+ }
if (strcmp(symname, "cleanup_module") == 0)
mod->has_cleanup = 1;
break;
@@ -2097,6 +2150,13 @@ static void check_exports(struct module *mod)
basename++;
else
basename = mod->name;
+
+ if (exp->ns && !module_imports_namespace(mod, exp->ns)) {
+ warn("module %s uses symbol %s from namespace %s, "
+ "but does not import it.\n",
+ basename, exp->name, exp->ns);
+ }
+
if (!mod->gpl_compatible)
check_for_gpl_usage(exp->export, basename, exp->name);
check_for_unused(exp->export, basename, exp->name);
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index 8453d6ac2f77..9626bf3e7424 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -109,6 +109,11 @@ buf_printf(struct buffer *buf, const char *fmt, ...);
void
buf_write(struct buffer *buf, const char *s, int len);
+struct namespace_list {
+ struct namespace_list *next;
+ char namespace[0];
+};
+
struct module {
struct module *next;
const char *name;
@@ -121,6 +126,8 @@ struct module {
struct buffer dev_table_buf;
char srcversion[25];
int is_dot_o;
+ // Actual imported namespaces
+ struct namespace_list *imported_namespaces;
};
struct elf_info {
--
2.18.0.203.gfac676dfb9-goog
This change allows growing struct kernel_symbol without wasting bytes to
alignment.
struct kernel_symbol was already implicitly being aligned to the word
size, except on x86_64 and m68k, where it is aligned to 16 and 2 bytes,
respectively.
As far as I can tell there is no requirement for aligning struct
kernel_symbol to 16 bytes on x86_64, but gcc aligns structs to their
size, and the linker aligns the custom __ksymtab sections to the largest
data type contained within, so setting KSYM_ALIGN to 16 was necessary to
stay consistent with the code generated for non-ASM EXPORT_SYMBOL(). Now
that non-ASM EXPORT_SYMBOL() explicitly aligns to word size (8),
KSYM_ALIGN is no longer necessary.
As for m68k, struct kernel_symbol is aligned to 2 bytes even though the
structure itself is 8 bytes; using a 4-byte alignment shouldn't hurt.
I manually verified the output of the __ksymtab sections didn't change
on x86, x86_64, arm, arm64 and m68k. As expected, the section contents
didn't change, and the ELF section alignment only changed on x86_64 and
m68k. Feedback from other archs more than welcome.
Signed-off-by: Martijn Coenen <[email protected]>
---
arch/m68k/include/asm/export.h | 1 -
arch/x86/include/asm/Kbuild | 1 +
arch/x86/include/asm/export.h | 5 -----
include/linux/export.h | 1 +
4 files changed, 2 insertions(+), 6 deletions(-)
delete mode 100644 arch/x86/include/asm/export.h
diff --git a/arch/m68k/include/asm/export.h b/arch/m68k/include/asm/export.h
index 0af20f48bd07..b53008b67ce1 100644
--- a/arch/m68k/include/asm/export.h
+++ b/arch/m68k/include/asm/export.h
@@ -1,3 +1,2 @@
-#define KSYM_ALIGN 2
#define KCRC_ALIGN 2
#include <asm-generic/export.h>
diff --git a/arch/x86/include/asm/Kbuild b/arch/x86/include/asm/Kbuild
index de690c2d2e33..a0ab9ab61c75 100644
--- a/arch/x86/include/asm/Kbuild
+++ b/arch/x86/include/asm/Kbuild
@@ -8,5 +8,6 @@ generated-y += xen-hypercalls.h
generic-y += dma-contiguous.h
generic-y += early_ioremap.h
+generic-y += export.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
diff --git a/arch/x86/include/asm/export.h b/arch/x86/include/asm/export.h
deleted file mode 100644
index 2a51d66689c5..000000000000
--- a/arch/x86/include/asm/export.h
+++ /dev/null
@@ -1,5 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifdef CONFIG_64BIT
-#define KSYM_ALIGN 16
-#endif
-#include <asm-generic/export.h>
diff --git a/include/linux/export.h b/include/linux/export.h
index b768d6dd3c90..ad6b8e697b27 100644
--- a/include/linux/export.h
+++ b/include/linux/export.h
@@ -64,6 +64,7 @@ extern struct module __this_module;
static const struct kernel_symbol __ksymtab_##sym \
__used \
__attribute__((section("___ksymtab" sec "+" #sym), used)) \
+ __attribute__((aligned(sizeof(void *)))) \
= { (unsigned long)&sym, __kstrtab_##sym }
#if defined(__KSYM_DEPS__)
--
2.18.0.203.gfac676dfb9-goog
The EXPORT_SYMBOL_NS() and EXPORT_SYMBOL_NS_GPL() macros can be used to
export a symbol to a specific namespace. There are no _GPL_FUTURE and
_UNUSED variants because these are currently unused, and I'm not sure
they are necessary.
I didn't add EXPORT_SYMBOL_NS() for ASM exports; this patch sets the
namespace of ASM exports to NULL by default. If there's a need, this
should be pretty easy to add.
A module that wants to use a symbol exported to a namespace must add a
MODULE_IMPORT_NS() statement to their module code; otherwise, modpost
will complain when building the module, and the kernel module loader
will warn when loading the module.
The ELF symbols are renamed to include the namespace with an asm label;
for example, symbol 'usb_stor_suspend' in namespace USB_STORAGE becomes
'usb_stor_suspend.USB_STORAGE'. This allows modpost to do namespace
checking, without having to go through all the effort of parsing ELF and
reloction records just to get to the struct kernel_symbols.
On x86_64 I saw no difference in binary size (compression), but at
runtime this will require a word of memory per export to hold the
namespace. An alternative could be to store namespaced symbols in their
own section and use a separate 'struct namespaced_kernel_symbol' for
that section, at the cost of making the module loader more complex.
Signed-off-by: Martijn Coenen <[email protected]>
---
include/asm-generic/export.h | 2 +-
include/linux/export.h | 83 +++++++++++++++++++++++++++---------
include/linux/module.h | 13 ++++++
kernel/module.c | 79 ++++++++++++++++++++++++++++++++++
4 files changed, 156 insertions(+), 21 deletions(-)
diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h
index 68efb950a918..4c3d1afb702f 100644
--- a/include/asm-generic/export.h
+++ b/include/asm-generic/export.h
@@ -29,7 +29,7 @@
.section ___ksymtab\sec+\name,"a"
.balign KSYM_ALIGN
__ksymtab_\name:
- __put \val, __kstrtab_\name
+ __put \val, __kstrtab_\name, 0
.previous
.section __ksymtab_strings,"a"
__kstrtab_\name:
diff --git a/include/linux/export.h b/include/linux/export.h
index ad6b8e697b27..9f6e70eeb85f 100644
--- a/include/linux/export.h
+++ b/include/linux/export.h
@@ -22,6 +22,11 @@ struct kernel_symbol
{
unsigned long value;
const char *name;
+ const char *namespace;
+};
+
+struct namespace_import {
+ const char *namespace;
};
#ifdef MODULE
@@ -54,18 +59,28 @@ extern struct module __this_module;
#define __CRC_SYMBOL(sym, sec)
#endif
+#define NS_SEPARATOR "."
+
+#define MODULE_IMPORT_NS(ns) \
+ static const struct namespace_import __knsimport_##ns \
+ asm("__knsimport_" #ns) \
+ __attribute__((section("__knsimport"), used)) \
+ = { #ns }
+
/* For every exported symbol, place a struct in the __ksymtab section */
-#define ___EXPORT_SYMBOL(sym, sec) \
+#define ___EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2) \
extern typeof(sym) sym; \
__CRC_SYMBOL(sym, sec) \
- static const char __kstrtab_##sym[] \
+ static const char __kstrtab_##sym##nspost[] \
__attribute__((section("__ksymtab_strings"), aligned(1))) \
= #sym; \
- static const struct kernel_symbol __ksymtab_##sym \
+ static const struct kernel_symbol __ksymtab_##sym##nspost \
+ asm("__ksymtab_" #sym nspost2) \
__used \
- __attribute__((section("___ksymtab" sec "+" #sym), used)) \
+ __attribute__((section("___ksymtab" sec "+" #sym #nspost))) \
+ __attribute__((used)) \
__attribute__((aligned(sizeof(void *)))) \
- = { (unsigned long)&sym, __kstrtab_##sym }
+ = { (unsigned long)&sym, __kstrtab_##sym##nspost, ns }
#if defined(__KSYM_DEPS__)
@@ -76,52 +91,80 @@ extern struct module __this_module;
* system filters out from the preprocessor output (see ksym_dep_filter
* in scripts/Kbuild.include).
*/
-#define __EXPORT_SYMBOL(sym, sec) === __KSYM_##sym ===
+#define __EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2) === __KSYM_##sym ===
#elif defined(CONFIG_TRIM_UNUSED_KSYMS)
#include <generated/autoksyms.h>
-#define __EXPORT_SYMBOL(sym, sec) \
- __cond_export_sym(sym, sec, __is_defined(__KSYM_##sym))
-#define __cond_export_sym(sym, sec, conf) \
- ___cond_export_sym(sym, sec, conf)
-#define ___cond_export_sym(sym, sec, enabled) \
- __cond_export_sym_##enabled(sym, sec)
-#define __cond_export_sym_1(sym, sec) ___EXPORT_SYMBOL(sym, sec)
-#define __cond_export_sym_0(sym, sec) /* nothing */
+#define __EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2) \
+ __cond_export_sym(sym, sec, ns, nspost, nspost2, \
+ __is_defined(__KSYM_##sym))
+#define __cond_export_sym(sym, sec, ns, nspost, nspost2, conf) \
+ ___cond_export_sym(sym, sec, ns, nspost, nspost2, conf)
+#define ___cond_export_sym(sym, sec, ns, nspost, nspost2, enabled) \
+ __cond_export_sym_##enabled(sym, sec, ns, nspost, nspost2)
+#define __cond_export_sym_1(sym, sec, ns, nspost, nspost2) \
+ ___EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2)
+#define __cond_export_sym_0(sym, sec, ns, nspost, nspost2) /* nothing */
#else
#define __EXPORT_SYMBOL ___EXPORT_SYMBOL
#endif
#define EXPORT_SYMBOL(sym) \
- __EXPORT_SYMBOL(sym, "")
+ __EXPORT_SYMBOL(sym, "", NULL, ,)
#define EXPORT_SYMBOL_GPL(sym) \
- __EXPORT_SYMBOL(sym, "_gpl")
+ __EXPORT_SYMBOL(sym, "_gpl", NULL, ,)
#define EXPORT_SYMBOL_GPL_FUTURE(sym) \
- __EXPORT_SYMBOL(sym, "_gpl_future")
+ __EXPORT_SYMBOL(sym, "_gpl_future", NULL, ,)
+
+#define EXPORT_SYMBOL_NS(sym, ns) \
+ __EXPORT_SYMBOL(sym, "", #ns, __##ns, NS_SEPARATOR #ns)
+
+#define EXPORT_SYMBOL_NS_GPL(sym, ns) \
+ __EXPORT_SYMBOL(sym, "_gpl", #ns, __##ns, NS_SEPARATOR #ns)
#ifdef CONFIG_UNUSED_SYMBOLS
-#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused")
-#define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl")
+#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused", , ,)
+#define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl", , ,)
#else
#define EXPORT_UNUSED_SYMBOL(sym)
#define EXPORT_UNUSED_SYMBOL_GPL(sym)
#endif
-#endif /* __GENKSYMS__ */
+#endif /* __KERNEL__ && !__GENKSYMS__ */
+
+#if defined(__GENKSYMS__)
+/*
+ * When we're running genksyms, ignore the namespace and make the _NS
+ * variants look like the normal ones. There are two reasons for this:
+ * 1) In the normal definition of EXPORT_SYMBOL_NS, the 'ns' macro
+ * argument is itself not expanded because it's always tokenized or
+ * concatenated; but when running genksyms, a blank definition of the
+ * macro does allow the argument to be expanded; if a namespace
+ * happens to collide with a #define, this can cause issues.
+ * 2) There's no need to modify genksyms to deal with the _NS variants
+ */
+#define EXPORT_SYMBOL_NS(sym, ns) \
+ EXPORT_SYMBOL(sym)
+#define EXPORT_SYMBOL_NS_GPL(sym, ns) \
+ EXPORT_SYMBOL_GPL(sym)
+#endif
#else /* !CONFIG_MODULES... */
#define EXPORT_SYMBOL(sym)
+#define EXPORT_SYMBOL_NS(sym, ns)
+#define EXPORT_SYMBOL_NS_GPL(sym, ns)
#define EXPORT_SYMBOL_GPL(sym)
#define EXPORT_SYMBOL_GPL_FUTURE(sym)
#define EXPORT_UNUSED_SYMBOL(sym)
#define EXPORT_UNUSED_SYMBOL_GPL(sym)
+#define MODULE_IMPORT_NS(ns)
#endif /* CONFIG_MODULES */
#endif /* !__ASSEMBLY__ */
diff --git a/include/linux/module.h b/include/linux/module.h
index d44df9b2c131..afab4e8fa188 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -268,6 +268,12 @@ void *__symbol_get(const char *symbol);
void *__symbol_get_gpl(const char *symbol);
#define symbol_get(x) ((typeof(&x))(__symbol_get(VMLINUX_SYMBOL_STR(x))))
+/* namespace dependencies of the module */
+struct module_ns_dep {
+ struct list_head ns_dep;
+ const char *namespace;
+};
+
/* modules using other modules: kdb wants to see this. */
struct module_use {
struct list_head source_list;
@@ -359,6 +365,13 @@ struct module {
const struct kernel_symbol *gpl_syms;
const s32 *gpl_crcs;
+ /* Namespace imports */
+ unsigned int num_ns_imports;
+ const struct namespace_import *ns_imports;
+
+ /* Namespace dependencies */
+ struct list_head ns_dependencies;
+
#ifdef CONFIG_UNUSED_SYMBOLS
/* unused exported symbols. */
const struct kernel_symbol *unused_syms;
diff --git a/kernel/module.c b/kernel/module.c
index f475f30eed8c..63de0fe849f9 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1166,6 +1166,51 @@ static inline int module_unload_init(struct module *mod)
}
#endif /* CONFIG_MODULE_UNLOAD */
+static bool module_has_ns_dependency(struct module *mod, const char *ns)
+{
+ struct module_ns_dep *ns_dep;
+
+ list_for_each_entry(ns_dep, &mod->ns_dependencies, ns_dep) {
+ if (strcmp(ns_dep->namespace, ns) == 0)
+ return true;
+ }
+
+ return false;
+}
+
+static int add_module_ns_dependency(struct module *mod, const char *ns)
+{
+ struct module_ns_dep *ns_dep;
+
+ if (module_has_ns_dependency(mod, ns))
+ return 0;
+
+ ns_dep = kmalloc(sizeof(*ns_dep), GFP_ATOMIC);
+ if (!ns_dep)
+ return -ENOMEM;
+
+ ns_dep->namespace = ns;
+
+ list_add(&ns_dep->ns_dep, &mod->ns_dependencies);
+
+ return 0;
+}
+
+static bool module_imports_ns(struct module *mod, const char *ns)
+{
+ size_t i;
+
+ if (!ns)
+ return true;
+
+ for (i = 0; i < mod->num_ns_imports; ++i) {
+ if (!strcmp(mod->ns_imports[i].namespace, ns))
+ return true;
+ }
+
+ return false;
+}
+
static size_t module_flags_taint(struct module *mod, char *buf)
{
size_t l = 0;
@@ -1415,6 +1460,18 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
goto getname;
}
+ /*
+ * We can't yet verify that the module actually imports this
+ * namespace, because the imports themselves are only available
+ * after processing the symbol table and doing relocation; so
+ * instead just record the dependency and check later.
+ */
+ if (sym->namespace) {
+ err = add_module_ns_dependency(mod, sym->namespace);
+ if (err)
+ sym = ERR_PTR(err);
+ }
+
getname:
/* We must make copy under the lock if we failed to get ref. */
strncpy(ownername, module_name(owner), MODULE_NAME_LEN);
@@ -3061,6 +3118,11 @@ static int find_module_sections(struct module *mod, struct load_info *info)
sizeof(*mod->gpl_syms),
&mod->num_gpl_syms);
mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
+
+ mod->ns_imports = section_objs(info, "__knsimport",
+ sizeof(*mod->ns_imports),
+ &mod->num_ns_imports);
+
mod->gpl_future_syms = section_objs(info,
"__ksymtab_gpl_future",
sizeof(*mod->gpl_future_syms),
@@ -3381,6 +3443,19 @@ static int post_relocation(struct module *mod, const struct load_info *info)
return module_finalize(info->hdr, info->sechdrs, mod);
}
+static void verify_namespace_dependencies(struct module *mod)
+{
+ struct module_ns_dep *ns_dep;
+
+ list_for_each_entry(ns_dep, &mod->ns_dependencies, ns_dep) {
+ if (!module_imports_ns(mod, ns_dep->namespace)) {
+ pr_warn("%s: module uses symbols from namespace %s,"
+ " but does not import it.\n",
+ mod->name, ns_dep->namespace);
+ }
+ }
+}
+
/* Is this module of this name done loading? No locks held. */
static bool finished_loading(const char *name)
{
@@ -3682,6 +3757,8 @@ static int load_module(struct load_info *info, const char __user *uargs,
if (err)
goto free_module;
+ INIT_LIST_HEAD(&mod->ns_dependencies);
+
#ifdef CONFIG_MODULE_SIG
mod->sig_ok = info->sig_ok;
if (!mod->sig_ok) {
@@ -3730,6 +3807,8 @@ static int load_module(struct load_info *info, const char __user *uargs,
if (err < 0)
goto free_modinfo;
+ verify_namespace_dependencies(mod);
+
flush_module_icache(mod);
/* Now copy in args */
--
2.18.0.203.gfac676dfb9-goog
On Mon, Jul 16, 2018 at 02:21:19PM +0200, Martijn Coenen wrote:
> As of Linux 4.17, there are more than 30000 exported symbols
> in the kernel. There seems to be some consensus amongst
> kernel devs that the export surface is too large, and hard
> to reason about.
>
> Generally, these symbols fall in one of these categories:
> 1) Symbols actually meant for drivers
> 2) Symbols that are only exported because functionality is
> split over multiple modules, yet they really shouldn't
> be used by modules outside of their own subsystem
> 3) Symbols really only meant for in-tree use
>
> When module developers try to upstream their code, it
> regularly turns out that they are using exported symbols
> that they really shouldn't be using. This problem is even
> bigger for drivers that are currently out-of-tree, which
> may be using many symbols that they shouldn't be using,
> and that break when those symbols are removed or modified.
>
> This patch allows subsystem maintainers to partition their
> exported symbols into separate namespaces, and module
> authors to import such namespaces only when needed.
>
> This allows subsystem maintainers to more easily limit
> availability of these namespaced symbols to other parts of
> the kernel. It can also be used to partition the set of
> exported symbols for documentation purposes; for example,
> a set of symbols that is really only used for debugging
> could be in a "SUBSYSTEM_DEBUG" namespace.
To give people a bit more background here, this is something that both
Andi Kleen and I talked about over a decade ago. Martijn based his work
on Andi's original patches and made them all work well, something that I
was unable to do :)
His addition of using the build system to automatically generate a patch
for a subsystem based on the symbol namespace changes is frickin
amazing.
Great work here, this is something that I have wanted for the kernel for
a long time.
greg k-h
On Mon, 16 Jul 2018, Martijn Coenen wrote:
> Modules using these symbols must now import this namesapce explicitly.
Spelling error ("namesapce").
>
> Signed-off-by: Martijn Coenen <[email protected]>
> ---
> drivers/usb/storage/alauda.c | 1 +
> drivers/usb/storage/cypress_atacb.c | 1 +
> drivers/usb/storage/datafab.c | 1 +
> drivers/usb/storage/ene_ub6250.c | 1 +
> drivers/usb/storage/freecom.c | 1 +
> drivers/usb/storage/isd200.c | 1 +
> drivers/usb/storage/jumpshot.c | 1 +
> drivers/usb/storage/karma.c | 1 +
> drivers/usb/storage/onetouch.c | 1 +
> drivers/usb/storage/realtek_cr.c | 1 +
> drivers/usb/storage/sddr09.c | 1 +
> drivers/usb/storage/sddr55.c | 1 +
> drivers/usb/storage/shuttle_usbat.c | 1 +
> drivers/usb/storage/uas.c | 1 +
> drivers/usb/storage/usb.c | 20 ++++++++++----------
> 15 files changed, 24 insertions(+), 10 deletions(-)
This patch misses the various EXPORT_SYMBOL_GPL lines in debug.c,
protocol.c, scsiglue.c, and transport.c. They should also be
considered part of the USB_STORAGE namespace.
Alan Stern
On Tue, Jul 17, 2018 at 5:04 PM, Alan Stern <[email protected]> wrote:
> This patch misses the various EXPORT_SYMBOL_GPL lines in debug.c,
> protocol.c, scsiglue.c, and transport.c. They should also be
> considered part of the USB_STORAGE namespace.
Thanks! I'd been using the usb.c symbols as my test vehicle forever,
and I forgot to check whether there were others. I'll make sure to
include them in the next series.
Martijn
>
> Alan Stern
>
+++ Martijn Coenen [16/07/18 14:21 +0200]:
>The EXPORT_SYMBOL_NS() and EXPORT_SYMBOL_NS_GPL() macros can be used to
>export a symbol to a specific namespace. There are no _GPL_FUTURE and
>_UNUSED variants because these are currently unused, and I'm not sure
>they are necessary.
>
>I didn't add EXPORT_SYMBOL_NS() for ASM exports; this patch sets the
>namespace of ASM exports to NULL by default. If there's a need, this
>should be pretty easy to add.
>
>A module that wants to use a symbol exported to a namespace must add a
>MODULE_IMPORT_NS() statement to their module code; otherwise, modpost
>will complain when building the module, and the kernel module loader
>will warn when loading the module.
>
>The ELF symbols are renamed to include the namespace with an asm label;
>for example, symbol 'usb_stor_suspend' in namespace USB_STORAGE becomes
>'usb_stor_suspend.USB_STORAGE'. This allows modpost to do namespace
>checking, without having to go through all the effort of parsing ELF and
>reloction records just to get to the struct kernel_symbols.
>
>On x86_64 I saw no difference in binary size (compression), but at
>runtime this will require a word of memory per export to hold the
>namespace. An alternative could be to store namespaced symbols in their
>own section and use a separate 'struct namespaced_kernel_symbol' for
>that section, at the cost of making the module loader more complex.
>
>Signed-off-by: Martijn Coenen <[email protected]>
>---
> include/asm-generic/export.h | 2 +-
> include/linux/export.h | 83 +++++++++++++++++++++++++++---------
> include/linux/module.h | 13 ++++++
> kernel/module.c | 79 ++++++++++++++++++++++++++++++++++
> 4 files changed, 156 insertions(+), 21 deletions(-)
>
>diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h
>index 68efb950a918..4c3d1afb702f 100644
>--- a/include/asm-generic/export.h
>+++ b/include/asm-generic/export.h
>@@ -29,7 +29,7 @@
> .section ___ksymtab\sec+\name,"a"
> .balign KSYM_ALIGN
> __ksymtab_\name:
>- __put \val, __kstrtab_\name
>+ __put \val, __kstrtab_\name, 0
> .previous
> .section __ksymtab_strings,"a"
> __kstrtab_\name:
>diff --git a/include/linux/export.h b/include/linux/export.h
>index ad6b8e697b27..9f6e70eeb85f 100644
>--- a/include/linux/export.h
>+++ b/include/linux/export.h
>@@ -22,6 +22,11 @@ struct kernel_symbol
> {
> unsigned long value;
> const char *name;
>+ const char *namespace;
>+};
>+
>+struct namespace_import {
>+ const char *namespace;
> };
>
> #ifdef MODULE
>@@ -54,18 +59,28 @@ extern struct module __this_module;
> #define __CRC_SYMBOL(sym, sec)
> #endif
>
>+#define NS_SEPARATOR "."
>+
>+#define MODULE_IMPORT_NS(ns) \
>+ static const struct namespace_import __knsimport_##ns \
>+ asm("__knsimport_" #ns) \
>+ __attribute__((section("__knsimport"), used)) \
>+ = { #ns }
>+
> /* For every exported symbol, place a struct in the __ksymtab section */
>-#define ___EXPORT_SYMBOL(sym, sec) \
>+#define ___EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2) \
> extern typeof(sym) sym; \
> __CRC_SYMBOL(sym, sec) \
>- static const char __kstrtab_##sym[] \
>+ static const char __kstrtab_##sym##nspost[] \
> __attribute__((section("__ksymtab_strings"), aligned(1))) \
> = #sym; \
>- static const struct kernel_symbol __ksymtab_##sym \
>+ static const struct kernel_symbol __ksymtab_##sym##nspost \
>+ asm("__ksymtab_" #sym nspost2) \
> __used \
>- __attribute__((section("___ksymtab" sec "+" #sym), used)) \
>+ __attribute__((section("___ksymtab" sec "+" #sym #nspost))) \
>+ __attribute__((used)) \
> __attribute__((aligned(sizeof(void *)))) \
>- = { (unsigned long)&sym, __kstrtab_##sym }
>+ = { (unsigned long)&sym, __kstrtab_##sym##nspost, ns }
>
> #if defined(__KSYM_DEPS__)
>
>@@ -76,52 +91,80 @@ extern struct module __this_module;
> * system filters out from the preprocessor output (see ksym_dep_filter
> * in scripts/Kbuild.include).
> */
>-#define __EXPORT_SYMBOL(sym, sec) === __KSYM_##sym ===
>+#define __EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2) === __KSYM_##sym ===
>
> #elif defined(CONFIG_TRIM_UNUSED_KSYMS)
>
> #include <generated/autoksyms.h>
>
>-#define __EXPORT_SYMBOL(sym, sec) \
>- __cond_export_sym(sym, sec, __is_defined(__KSYM_##sym))
>-#define __cond_export_sym(sym, sec, conf) \
>- ___cond_export_sym(sym, sec, conf)
>-#define ___cond_export_sym(sym, sec, enabled) \
>- __cond_export_sym_##enabled(sym, sec)
>-#define __cond_export_sym_1(sym, sec) ___EXPORT_SYMBOL(sym, sec)
>-#define __cond_export_sym_0(sym, sec) /* nothing */
>+#define __EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2) \
>+ __cond_export_sym(sym, sec, ns, nspost, nspost2, \
>+ __is_defined(__KSYM_##sym))
>+#define __cond_export_sym(sym, sec, ns, nspost, nspost2, conf) \
>+ ___cond_export_sym(sym, sec, ns, nspost, nspost2, conf)
>+#define ___cond_export_sym(sym, sec, ns, nspost, nspost2, enabled) \
>+ __cond_export_sym_##enabled(sym, sec, ns, nspost, nspost2)
>+#define __cond_export_sym_1(sym, sec, ns, nspost, nspost2) \
>+ ___EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2)
>+#define __cond_export_sym_0(sym, sec, ns, nspost, nspost2) /* nothing */
>
> #else
> #define __EXPORT_SYMBOL ___EXPORT_SYMBOL
> #endif
>
> #define EXPORT_SYMBOL(sym) \
>- __EXPORT_SYMBOL(sym, "")
>+ __EXPORT_SYMBOL(sym, "", NULL, ,)
>
> #define EXPORT_SYMBOL_GPL(sym) \
>- __EXPORT_SYMBOL(sym, "_gpl")
>+ __EXPORT_SYMBOL(sym, "_gpl", NULL, ,)
>
> #define EXPORT_SYMBOL_GPL_FUTURE(sym) \
>- __EXPORT_SYMBOL(sym, "_gpl_future")
>+ __EXPORT_SYMBOL(sym, "_gpl_future", NULL, ,)
>+
>+#define EXPORT_SYMBOL_NS(sym, ns) \
>+ __EXPORT_SYMBOL(sym, "", #ns, __##ns, NS_SEPARATOR #ns)
>+
>+#define EXPORT_SYMBOL_NS_GPL(sym, ns) \
>+ __EXPORT_SYMBOL(sym, "_gpl", #ns, __##ns, NS_SEPARATOR #ns)
>
> #ifdef CONFIG_UNUSED_SYMBOLS
>-#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused")
>-#define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl")
>+#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused", , ,)
>+#define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl", , ,)
> #else
> #define EXPORT_UNUSED_SYMBOL(sym)
> #define EXPORT_UNUSED_SYMBOL_GPL(sym)
> #endif
>
>-#endif /* __GENKSYMS__ */
>+#endif /* __KERNEL__ && !__GENKSYMS__ */
>+
>+#if defined(__GENKSYMS__)
>+/*
>+ * When we're running genksyms, ignore the namespace and make the _NS
>+ * variants look like the normal ones. There are two reasons for this:
>+ * 1) In the normal definition of EXPORT_SYMBOL_NS, the 'ns' macro
>+ * argument is itself not expanded because it's always tokenized or
>+ * concatenated; but when running genksyms, a blank definition of the
>+ * macro does allow the argument to be expanded; if a namespace
>+ * happens to collide with a #define, this can cause issues.
>+ * 2) There's no need to modify genksyms to deal with the _NS variants
>+ */
>+#define EXPORT_SYMBOL_NS(sym, ns) \
>+ EXPORT_SYMBOL(sym)
>+#define EXPORT_SYMBOL_NS_GPL(sym, ns) \
>+ EXPORT_SYMBOL_GPL(sym)
>+#endif
>
> #else /* !CONFIG_MODULES... */
>
> #define EXPORT_SYMBOL(sym)
>+#define EXPORT_SYMBOL_NS(sym, ns)
>+#define EXPORT_SYMBOL_NS_GPL(sym, ns)
> #define EXPORT_SYMBOL_GPL(sym)
> #define EXPORT_SYMBOL_GPL_FUTURE(sym)
> #define EXPORT_UNUSED_SYMBOL(sym)
> #define EXPORT_UNUSED_SYMBOL_GPL(sym)
>
>+#define MODULE_IMPORT_NS(ns)
> #endif /* CONFIG_MODULES */
> #endif /* !__ASSEMBLY__ */
>
>diff --git a/include/linux/module.h b/include/linux/module.h
>index d44df9b2c131..afab4e8fa188 100644
>--- a/include/linux/module.h
>+++ b/include/linux/module.h
>@@ -268,6 +268,12 @@ void *__symbol_get(const char *symbol);
> void *__symbol_get_gpl(const char *symbol);
> #define symbol_get(x) ((typeof(&x))(__symbol_get(VMLINUX_SYMBOL_STR(x))))
>
>+/* namespace dependencies of the module */
>+struct module_ns_dep {
>+ struct list_head ns_dep;
>+ const char *namespace;
>+};
>+
> /* modules using other modules: kdb wants to see this. */
> struct module_use {
> struct list_head source_list;
>@@ -359,6 +365,13 @@ struct module {
> const struct kernel_symbol *gpl_syms;
> const s32 *gpl_crcs;
>
>+ /* Namespace imports */
>+ unsigned int num_ns_imports;
>+ const struct namespace_import *ns_imports;
>+
>+ /* Namespace dependencies */
>+ struct list_head ns_dependencies;
>+
> #ifdef CONFIG_UNUSED_SYMBOLS
> /* unused exported symbols. */
> const struct kernel_symbol *unused_syms;
>diff --git a/kernel/module.c b/kernel/module.c
>index f475f30eed8c..63de0fe849f9 100644
>--- a/kernel/module.c
>+++ b/kernel/module.c
>@@ -1166,6 +1166,51 @@ static inline int module_unload_init(struct module *mod)
> }
> #endif /* CONFIG_MODULE_UNLOAD */
>
>+static bool module_has_ns_dependency(struct module *mod, const char *ns)
>+{
>+ struct module_ns_dep *ns_dep;
>+
>+ list_for_each_entry(ns_dep, &mod->ns_dependencies, ns_dep) {
>+ if (strcmp(ns_dep->namespace, ns) == 0)
>+ return true;
>+ }
>+
>+ return false;
>+}
>+
>+static int add_module_ns_dependency(struct module *mod, const char *ns)
>+{
>+ struct module_ns_dep *ns_dep;
>+
>+ if (module_has_ns_dependency(mod, ns))
>+ return 0;
>+
>+ ns_dep = kmalloc(sizeof(*ns_dep), GFP_ATOMIC);
>+ if (!ns_dep)
>+ return -ENOMEM;
>+
>+ ns_dep->namespace = ns;
>+
>+ list_add(&ns_dep->ns_dep, &mod->ns_dependencies);
>+
>+ return 0;
>+}
>+
>+static bool module_imports_ns(struct module *mod, const char *ns)
>+{
>+ size_t i;
>+
>+ if (!ns)
>+ return true;
>+
>+ for (i = 0; i < mod->num_ns_imports; ++i) {
>+ if (!strcmp(mod->ns_imports[i].namespace, ns))
>+ return true;
>+ }
>+
>+ return false;
>+}
>+
> static size_t module_flags_taint(struct module *mod, char *buf)
> {
> size_t l = 0;
>@@ -1415,6 +1460,18 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
> goto getname;
> }
>
>+ /*
>+ * We can't yet verify that the module actually imports this
>+ * namespace, because the imports themselves are only available
>+ * after processing the symbol table and doing relocation; so
>+ * instead just record the dependency and check later.
>+ */
>+ if (sym->namespace) {
>+ err = add_module_ns_dependency(mod, sym->namespace);
>+ if (err)
>+ sym = ERR_PTR(err);
>+ }
>+
First, thanks a lot for the patchset. This is definitely something that
will help distros as well to declutter the exported symbol space and
provide a more cleanly defined kernel interface.
Hm, I'm wondering if we could avoid all this extra module-ns-dependency
checking work if we just put the import stuff as a modinfo tag, like
have MODULE_IMPORT_NS() insert an "import:" tag like we already do for
module parameters, author, license, aliases, etc. Then we'd have that
information pretty much from the start of load_module() and we don't
need to wait for relocations to be applied to __knsimport. Then you
could do the namespace checking right at resolve_symbol() instead of
going through the extra step of building a dependency list to be
verified later.
Also, this would get rid of the extra __knsimport section, the extra
ns_dependencies field in struct module, and all those helper functions that
manage it. In addition, having the modinfo tag may potentially help with
debugging as we have the namespace imports clearly listed if we don't have
the source code for a module. We'd probably need to modify get_modinfo() to
handle multiple import: tags though. Luis [1] had written some code a while
ago to handle multiple (of the same) modinfo tags.
Thoughts on this?
Thanks,
Jessica
[1] https://lkml.kernel.org/r/[email protected]
> getname:
> /* We must make copy under the lock if we failed to get ref. */
> strncpy(ownername, module_name(owner), MODULE_NAME_LEN);
>@@ -3061,6 +3118,11 @@ static int find_module_sections(struct module *mod, struct load_info *info)
> sizeof(*mod->gpl_syms),
> &mod->num_gpl_syms);
> mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
>+
>+ mod->ns_imports = section_objs(info, "__knsimport",
>+ sizeof(*mod->ns_imports),
>+ &mod->num_ns_imports);
>+
> mod->gpl_future_syms = section_objs(info,
> "__ksymtab_gpl_future",
> sizeof(*mod->gpl_future_syms),
>@@ -3381,6 +3443,19 @@ static int post_relocation(struct module *mod, const struct load_info *info)
> return module_finalize(info->hdr, info->sechdrs, mod);
> }
>
>+static void verify_namespace_dependencies(struct module *mod)
>+{
>+ struct module_ns_dep *ns_dep;
>+
>+ list_for_each_entry(ns_dep, &mod->ns_dependencies, ns_dep) {
>+ if (!module_imports_ns(mod, ns_dep->namespace)) {
>+ pr_warn("%s: module uses symbols from namespace %s,"
>+ " but does not import it.\n",
>+ mod->name, ns_dep->namespace);
>+ }
>+ }
>+}
>+
> /* Is this module of this name done loading? No locks held. */
> static bool finished_loading(const char *name)
> {
>@@ -3682,6 +3757,8 @@ static int load_module(struct load_info *info, const char __user *uargs,
> if (err)
> goto free_module;
>
>+ INIT_LIST_HEAD(&mod->ns_dependencies);
>+
> #ifdef CONFIG_MODULE_SIG
> mod->sig_ok = info->sig_ok;
> if (!mod->sig_ok) {
>@@ -3730,6 +3807,8 @@ static int load_module(struct load_info *info, const char __user *uargs,
> if (err < 0)
> goto free_modinfo;
>
>+ verify_namespace_dependencies(mod);
>+
> flush_module_icache(mod);
>
> /* Now copy in args */
>--
>2.18.0.203.gfac676dfb9-goog
>
Hi Jessica,
On Thu, Jul 19, 2018 at 6:32 PM, Jessica Yu <[email protected]> wrote:
> First, thanks a lot for the patchset. This is definitely something that
> will help distros as well to declutter the exported symbol space and
> provide a more cleanly defined kernel interface.
Thanks, that's good to hear!
> Hm, I'm wondering if we could avoid all this extra module-ns-dependency
> checking work if we just put the import stuff as a modinfo tag, like
> have MODULE_IMPORT_NS() insert an "import:" tag like we already do for
> module parameters, author, license, aliases, etc. Then we'd have that
> information pretty much from the start of load_module() and we don't
> need to wait for relocations to be applied to __knsimport. Then you
> could do the namespace checking right at resolve_symbol() instead of
> going through the extra step of building a dependency list to be
> verified later.
I believe I did consider modinfo when I started with this a while
back, but don't recall right now why I didn't decide to use it;
perhaps it was the lack of support for multiple identical tags. Since
both modpost and the module loader have access to them, I don't see
why it wouldn't work, and indeed I suspect it would make the module
loader a bit simpler. I'll rework this and see what it looks like.
Thanks,
Martijn
>
> Also, this would get rid of the extra __knsimport section, the extra
> ns_dependencies field in struct module, and all those helper functions that
> manage it. In addition, having the modinfo tag may potentially help with
> debugging as we have the namespace imports clearly listed if we don't have
> the source code for a module. We'd probably need to modify get_modinfo() to
> handle multiple import: tags though. Luis [1] had written some code a while
> ago to handle multiple (of the same) modinfo tags.
>
> Thoughts on this?
>
> Thanks,
>
> Jessica
>
> [1] https://lkml.kernel.org/r/[email protected]
>
>
>> getname:
>> /* We must make copy under the lock if we failed to get ref. */
>> strncpy(ownername, module_name(owner), MODULE_NAME_LEN);
>> @@ -3061,6 +3118,11 @@ static int find_module_sections(struct module *mod,
>> struct load_info *info)
>> sizeof(*mod->gpl_syms),
>> &mod->num_gpl_syms);
>> mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
>> +
>> + mod->ns_imports = section_objs(info, "__knsimport",
>> + sizeof(*mod->ns_imports),
>> + &mod->num_ns_imports);
>> +
>> mod->gpl_future_syms = section_objs(info,
>> "__ksymtab_gpl_future",
>> sizeof(*mod->gpl_future_syms),
>> @@ -3381,6 +3443,19 @@ static int post_relocation(struct module *mod,
>> const struct load_info *info)
>> return module_finalize(info->hdr, info->sechdrs, mod);
>> }
>>
>> +static void verify_namespace_dependencies(struct module *mod)
>> +{
>> + struct module_ns_dep *ns_dep;
>> +
>> + list_for_each_entry(ns_dep, &mod->ns_dependencies, ns_dep) {
>> + if (!module_imports_ns(mod, ns_dep->namespace)) {
>> + pr_warn("%s: module uses symbols from namespace
>> %s,"
>> + " but does not import it.\n",
>> + mod->name, ns_dep->namespace);
>> + }
>> + }
>> +}
>> +
>> /* Is this module of this name done loading? No locks held. */
>> static bool finished_loading(const char *name)
>> {
>> @@ -3682,6 +3757,8 @@ static int load_module(struct load_info *info, const
>> char __user *uargs,
>> if (err)
>> goto free_module;
>>
>> + INIT_LIST_HEAD(&mod->ns_dependencies);
>> +
>> #ifdef CONFIG_MODULE_SIG
>> mod->sig_ok = info->sig_ok;
>> if (!mod->sig_ok) {
>> @@ -3730,6 +3807,8 @@ static int load_module(struct load_info *info, const
>> char __user *uargs,
>> if (err < 0)
>> goto free_modinfo;
>>
>> + verify_namespace_dependencies(mod);
>> +
>> flush_module_icache(mod);
>>
>> /* Now copy in args */
>> --
>> 2.18.0.203.gfac676dfb9-goog
>>
>
+++ Martijn Coenen [20/07/18 09:54 +0200]:
>Hi Jessica,
>
>On Thu, Jul 19, 2018 at 6:32 PM, Jessica Yu <[email protected]> wrote:
>> First, thanks a lot for the patchset. This is definitely something that
>> will help distros as well to declutter the exported symbol space and
>> provide a more cleanly defined kernel interface.
>
>Thanks, that's good to hear!
>
>
>> Hm, I'm wondering if we could avoid all this extra module-ns-dependency
>> checking work if we just put the import stuff as a modinfo tag, like
>> have MODULE_IMPORT_NS() insert an "import:" tag like we already do for
>> module parameters, author, license, aliases, etc. Then we'd have that
>> information pretty much from the start of load_module() and we don't
>> need to wait for relocations to be applied to __knsimport. Then you
>> could do the namespace checking right at resolve_symbol() instead of
>> going through the extra step of building a dependency list to be
>> verified later.
>
>I believe I did consider modinfo when I started with this a while
>back, but don't recall right now why I didn't decide to use it;
>perhaps it was the lack of support for multiple identical tags. Since
>both modpost and the module loader have access to them, I don't see
>why it wouldn't work, and indeed I suspect it would make the module
>loader a bit simpler. I'll rework this and see what it looks like.
Thanks. Also, it looks like we're currently just warning (in both
modpost and on module load) if a module uses symbols from a namespace
it doesn't import. Are you also planning to eventually introduce
namespace enforcement? It'd be trivial to fail the module build in
modpost as well as reject the module on load if it uses an exported
symbol belonging to a namespace it doesn't import. Although, I'd go
with the warnings for a development cycle or two, to gently introduce
the change in API and let other subsystems as well as out-of-tree
module developers catch up.
Jessica
>> Also, this would get rid of the extra __knsimport section, the extra
>> ns_dependencies field in struct module, and all those helper functions that
>> manage it. In addition, having the modinfo tag may potentially help with
>> debugging as we have the namespace imports clearly listed if we don't have
>> the source code for a module. We'd probably need to modify get_modinfo() to
>> handle multiple import: tags though. Luis [1] had written some code a while
>> ago to handle multiple (of the same) modinfo tags.
>>
>> Thoughts on this?
>>
>> Thanks,
>>
>> Jessica
>>
>> [1] https://lkml.kernel.org/r/[email protected]
>>
>>
>>> getname:
>>> /* We must make copy under the lock if we failed to get ref. */
>>> strncpy(ownername, module_name(owner), MODULE_NAME_LEN);
>>> @@ -3061,6 +3118,11 @@ static int find_module_sections(struct module *mod,
>>> struct load_info *info)
>>> sizeof(*mod->gpl_syms),
>>> &mod->num_gpl_syms);
>>> mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
>>> +
>>> + mod->ns_imports = section_objs(info, "__knsimport",
>>> + sizeof(*mod->ns_imports),
>>> + &mod->num_ns_imports);
>>> +
>>> mod->gpl_future_syms = section_objs(info,
>>> "__ksymtab_gpl_future",
>>> sizeof(*mod->gpl_future_syms),
>>> @@ -3381,6 +3443,19 @@ static int post_relocation(struct module *mod,
>>> const struct load_info *info)
>>> return module_finalize(info->hdr, info->sechdrs, mod);
>>> }
>>>
>>> +static void verify_namespace_dependencies(struct module *mod)
>>> +{
>>> + struct module_ns_dep *ns_dep;
>>> +
>>> + list_for_each_entry(ns_dep, &mod->ns_dependencies, ns_dep) {
>>> + if (!module_imports_ns(mod, ns_dep->namespace)) {
>>> + pr_warn("%s: module uses symbols from namespace
>>> %s,"
>>> + " but does not import it.\n",
>>> + mod->name, ns_dep->namespace);
>>> + }
>>> + }
>>> +}
>>> +
>>> /* Is this module of this name done loading? No locks held. */
>>> static bool finished_loading(const char *name)
>>> {
>>> @@ -3682,6 +3757,8 @@ static int load_module(struct load_info *info, const
>>> char __user *uargs,
>>> if (err)
>>> goto free_module;
>>>
>>> + INIT_LIST_HEAD(&mod->ns_dependencies);
>>> +
>>> #ifdef CONFIG_MODULE_SIG
>>> mod->sig_ok = info->sig_ok;
>>> if (!mod->sig_ok) {
>>> @@ -3730,6 +3807,8 @@ static int load_module(struct load_info *info, const
>>> char __user *uargs,
>>> if (err < 0)
>>> goto free_modinfo;
>>>
>>> + verify_namespace_dependencies(mod);
>>> +
>>> flush_module_icache(mod);
>>>
>>> /* Now copy in args */
>>> --
>>> 2.18.0.203.gfac676dfb9-goog
>>>
>>
On Fri, Jul 20, 2018 at 4:49 PM, Jessica Yu <[email protected]> wrote:
> Thanks. Also, it looks like we're currently just warning (in both
> modpost and on module load) if a module uses symbols from a namespace
> it doesn't import. Are you also planning to eventually introduce
> namespace enforcement?
This is something I've definitely been thinking about, and was curious
what others would think. My main concern with enforcement is that it
will start failing to load out-of-tree modules that use newly
namespaced symbols. On the other hand, I think those modules will need
to be rebuilt anyway to be able to load, because the changes to struct
kernel_symbol make them incompatible with the current kernel. That
could be another reason for having these symbols in a special section
(with its own struct namespaced_kernel_symbol); but on the other hand,
it would make the module loader more complex just to facilitate
out-of-tree drivers, and I'm not sure where the trade-off between
those two falls.
> It'd be trivial to fail the module build in
> modpost as well as reject the module on load if it uses an exported
> symbol belonging to a namespace it doesn't import. Although, I'd go
> with the warnings for a development cycle or two, to gently introduce
> the change in API and let other subsystems as well as out-of-tree
> module developers catch up.
An approach like that makes sense to me. Another alternative would be
to make it a CONFIG_ option, and let distros/etc. decide what they are
comfortable with.
Thanks,
Martijn
>
>
> Jessica
>
>
>>> Also, this would get rid of the extra __knsimport section, the extra
>>> ns_dependencies field in struct module, and all those helper functions
>>> that
>>> manage it. In addition, having the modinfo tag may potentially help with
>>> debugging as we have the namespace imports clearly listed if we don't
>>> have
>>> the source code for a module. We'd probably need to modify get_modinfo()
>>> to
>>> handle multiple import: tags though. Luis [1] had written some code a
>>> while
>>> ago to handle multiple (of the same) modinfo tags.
>>>
>>> Thoughts on this?
>>>
>>> Thanks,
>>>
>>> Jessica
>>>
>>> [1] https://lkml.kernel.org/r/[email protected]
>>>
>>>
>>>> getname:
>>>> /* We must make copy under the lock if we failed to get ref. */
>>>> strncpy(ownername, module_name(owner), MODULE_NAME_LEN);
>>>> @@ -3061,6 +3118,11 @@ static int find_module_sections(struct module
>>>> *mod,
>>>> struct load_info *info)
>>>> sizeof(*mod->gpl_syms),
>>>> &mod->num_gpl_syms);
>>>> mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
>>>> +
>>>> + mod->ns_imports = section_objs(info, "__knsimport",
>>>> + sizeof(*mod->ns_imports),
>>>> + &mod->num_ns_imports);
>>>> +
>>>> mod->gpl_future_syms = section_objs(info,
>>>> "__ksymtab_gpl_future",
>>>>
>>>> sizeof(*mod->gpl_future_syms),
>>>> @@ -3381,6 +3443,19 @@ static int post_relocation(struct module *mod,
>>>> const struct load_info *info)
>>>> return module_finalize(info->hdr, info->sechdrs, mod);
>>>> }
>>>>
>>>> +static void verify_namespace_dependencies(struct module *mod)
>>>> +{
>>>> + struct module_ns_dep *ns_dep;
>>>> +
>>>> + list_for_each_entry(ns_dep, &mod->ns_dependencies, ns_dep) {
>>>> + if (!module_imports_ns(mod, ns_dep->namespace)) {
>>>> + pr_warn("%s: module uses symbols from namespace
>>>> %s,"
>>>> + " but does not import it.\n",
>>>> + mod->name, ns_dep->namespace);
>>>> + }
>>>> + }
>>>> +}
>>>> +
>>>> /* Is this module of this name done loading? No locks held. */
>>>> static bool finished_loading(const char *name)
>>>> {
>>>> @@ -3682,6 +3757,8 @@ static int load_module(struct load_info *info,
>>>> const
>>>> char __user *uargs,
>>>> if (err)
>>>> goto free_module;
>>>>
>>>> + INIT_LIST_HEAD(&mod->ns_dependencies);
>>>> +
>>>> #ifdef CONFIG_MODULE_SIG
>>>> mod->sig_ok = info->sig_ok;
>>>> if (!mod->sig_ok) {
>>>> @@ -3730,6 +3807,8 @@ static int load_module(struct load_info *info,
>>>> const
>>>> char __user *uargs,
>>>> if (err < 0)
>>>> goto free_modinfo;
>>>>
>>>> + verify_namespace_dependencies(mod);
>>>> +
>>>> flush_module_icache(mod);
>>>>
>>>> /* Now copy in args */
>>>> --
>>>> 2.18.0.203.gfac676dfb9-goog
>>>>
>>>
>
+++ Martijn Coenen [16/07/18 14:21 +0200]:
>This patch adds an option to modpost to generate a .ns_deps file per
>module, containing the namespace depedencies for that module.
>
>This file can subsequently be used by other tools to automatically add
>newly introduced namespaces to the modules that require them, saving a
>lot of manual work.
>
>Signed-off-by: Martijn Coenen <[email protected]>
Regarding modpost, I think it may also be helpful to additionally
output the namespace an exported symbol belongs to (if any) in the
Module.symvers file.
>---
> scripts/mod/modpost.c | 58 +++++++++++++++++++++++++++++++++++++++----
> scripts/mod/modpost.h | 2 ++
> 2 files changed, 55 insertions(+), 5 deletions(-)
>
>diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
>index a56a8461a96a..be33d60d5527 100644
>--- a/scripts/mod/modpost.c
>+++ b/scripts/mod/modpost.c
>@@ -39,6 +39,8 @@ static int sec_mismatch_verbose = 1;
> static int sec_mismatch_fatal = 0;
> /* ignore missing files */
> static int ignore_missing_files;
>+/* Write namespace dependencies */
>+static int write_ns_deps;
>
> enum export {
> export_plain, export_unused, export_gpl,
>@@ -2151,10 +2153,15 @@ static void check_exports(struct module *mod)
> else
> basename = mod->name;
>
>- if (exp->ns && !module_imports_namespace(mod, exp->ns)) {
>- warn("module %s uses symbol %s from namespace %s, "
>- "but does not import it.\n",
>- basename, exp->name, exp->ns);
>+ if (exp->ns) {
>+ add_namespace(&mod->required_namespaces, exp->ns);
>+
>+ if (!write_ns_deps &&
>+ !module_imports_namespace(mod, exp->ns)) {
>+ warn("module %s uses symbol %s from namespace "
>+ "%s, but does not import it.\n",
>+ basename, exp->name, exp->ns);
>+ }
> }
>
> if (!mod->gpl_compatible)
>@@ -2457,6 +2464,38 @@ static void write_dump(const char *fname)
> free(buf.p);
> }
>
>+static void write_ns_deps_files(void)
>+{
>+ struct module *mod;
>+ struct namespace_list *ns;
>+ struct buffer ns_deps_buf = { };
>+
>+ for (mod = modules; mod; mod = mod->next) {
>+ char fname[PATH_MAX];
>+ const char *basename;
>+
>+ if (mod->skip)
>+ continue;
>+
>+ ns_deps_buf.pos = 0;
>+
>+ for (ns = mod->required_namespaces; ns; ns = ns->next)
>+ buf_printf(&ns_deps_buf, "%s\n", ns->namespace);
>+
>+ if (ns_deps_buf.pos == 0)
>+ continue;
>+
>+ basename = strrchr(mod->name, '/');
>+ if (basename)
>+ basename++;
>+ else
>+ basename = mod->name;
>+
>+ sprintf(fname, ".tmp_versions/%s.ns_deps", basename);
>+ write_if_changed(&ns_deps_buf, fname);
>+ }
>+}
>+
> struct ext_sym_list {
> struct ext_sym_list *next;
> const char *file;
>@@ -2473,7 +2512,7 @@ int main(int argc, char **argv)
> struct ext_sym_list *extsym_iter;
> struct ext_sym_list *extsym_start = NULL;
>
>- while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) {
>+ while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:Ed")) != -1) {
> switch (opt) {
> case 'i':
> kernel_read = optarg;
>@@ -2517,6 +2556,9 @@ int main(int argc, char **argv)
> case 'E':
> sec_mismatch_fatal = 1;
> break;
>+ case 'd':
>+ write_ns_deps = 1;
>+ break;
> default:
> exit(1);
> }
>@@ -2545,6 +2587,12 @@ int main(int argc, char **argv)
> check_exports(mod);
> }
>
>+ if (write_ns_deps) {
>+ /* Just write namespace dependencies and exit */
>+ write_ns_deps_files();
>+ return 0;
>+ }
>+
> err = 0;
>
> for (mod = modules; mod; mod = mod->next) {
>diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
>index 9626bf3e7424..92a926d375d2 100644
>--- a/scripts/mod/modpost.h
>+++ b/scripts/mod/modpost.h
>@@ -126,6 +126,8 @@ struct module {
> struct buffer dev_table_buf;
> char srcversion[25];
> int is_dot_o;
>+ // Required namespace dependencies
>+ struct namespace_list *required_namespaces;
> // Actual imported namespaces
> struct namespace_list *imported_namespaces;
> };
>--
>2.18.0.203.gfac676dfb9-goog
>
+++ Martijn Coenen [20/07/18 17:42 +0200]:
>On Fri, Jul 20, 2018 at 4:49 PM, Jessica Yu <[email protected]> wrote:
>> Thanks. Also, it looks like we're currently just warning (in both
>> modpost and on module load) if a module uses symbols from a namespace
>> it doesn't import. Are you also planning to eventually introduce
>> namespace enforcement?
>
>This is something I've definitely been thinking about, and was curious
>what others would think. My main concern with enforcement is that it
>will start failing to load out-of-tree modules that use newly
>namespaced symbols. On the other hand, I think those modules will need
>to be rebuilt anyway to be able to load, because the changes to struct
>kernel_symbol make them incompatible with the current kernel. That
>could be another reason for having these symbols in a special section
>(with its own struct namespaced_kernel_symbol); but on the other hand,
>it would make the module loader more complex just to facilitate
>out-of-tree drivers, and I'm not sure where the trade-off between
>those two falls.
IMO I don't think we should bend over backwards to accommodate
out-of-tree modules - modifying the module loader to recognize even
more special sections to accommodate these OOT modules would be where
we'd draw the line I think.
>> It'd be trivial to fail the module build in
>> modpost as well as reject the module on load if it uses an exported
>> symbol belonging to a namespace it doesn't import. Although, I'd go
>> with the warnings for a development cycle or two, to gently introduce
>> the change in API and let other subsystems as well as out-of-tree
>> module developers catch up.
>
>An approach like that makes sense to me. Another alternative would be
>to make it a CONFIG_ option, and let distros/etc. decide what they are
>comfortable with.
I think going forward I would prefer to have export namespaces to be a
normal and regular part of kernel API (as in, we shouldn't require a
new option for it), and that the warnings for 1-2 cycles are courteous
enough - but anyone with stronger opinions about this should speak up.
Thanks,
Jessica
On Mon, Jul 16, 2018 at 2:21 PM, Martijn Coenen <[email protected]> wrote:
> As of Linux 4.17, there are more than 30000 exported symbols
> in the kernel. There seems to be some consensus amongst
> kernel devs that the export surface is too large, and hard
> to reason about.
>
> Generally, these symbols fall in one of these categories:
> 1) Symbols actually meant for drivers
> 2) Symbols that are only exported because functionality is
> split over multiple modules, yet they really shouldn't
> be used by modules outside of their own subsystem
> 3) Symbols really only meant for in-tree use
>
> When module developers try to upstream their code, it
> regularly turns out that they are using exported symbols
> that they really shouldn't be using. This problem is even
> bigger for drivers that are currently out-of-tree, which
> may be using many symbols that they shouldn't be using,
> and that break when those symbols are removed or modified.
>
> This patch allows subsystem maintainers to partition their
> exported symbols into separate namespaces, and module
> authors to import such namespaces only when needed.
>
> This allows subsystem maintainers to more easily limit
> availability of these namespaced symbols to other parts of
> the kernel. It can also be used to partition the set of
> exported symbols for documentation purposes; for example,
> a set of symbols that is really only used for debugging
> could be in a "SUBSYSTEM_DEBUG" namespace.
This looks nice. I don't want to overload you with additional
requests, but it might be good to think about how this can
be taken further, if we want to actually convert large
parts of the kernel to it. I have two ideas:
- It would be nice to have a simple mechanism in Kconfig
to put all symbols in a module into a namespace that is
derived from KBUILD_MODNAME, to avoid having to
annotate every symbol separately. This could be similar
to how we ended up dealing with EXPORT_NO_SYMBOLS
in the linux-2.4 days, with the goal of eventually having
a namespace for each symbol. Similarly, we could pass
a number of default namespaces through the Makefile,
e.g. if we have a directory that has lots of drivers that all
import the symbols from a common subsystem module.
- If this is possible to implement, it would be great to have
a way to limit the globally visible symbols in a module
to the ones that are explicitly exported even when a that
module is built-in rather than loadable. Not sure how this
is best done though. A couple of things can be done with
objcopy, or possibly by reintroducing partial linking (which
was removed not too long ago).
Arnd
On Mon, Jul 23, 2018 at 1:12 PM, Jessica Yu <[email protected]> wrote:
> IMO I don't think we should bend over backwards to accommodate
> out-of-tree modules - modifying the module loader to recognize even
> more special sections to accommodate these OOT modules would be where
> we'd draw the line I think.
I agree with you, I really don't like making the module loader more
complex (which is why I didn't opt to create separate sections in the
first place), and in the end this change will in some ways benefit
out-of-tree drivers too, even though it will be a bit painful now.
> I think going forward I would prefer to have export namespaces to be a
> normal and regular part of kernel API (as in, we shouldn't require a
> new option for it), and that the warnings for 1-2 cycles are courteous
> enough - but anyone with stronger opinions about this should speak up.
That aligns with how I think about this; if we want this to be a
standard thing in the kernel, we should at some point enforce it,
because it's pretty easy to ignore the warning. The good thing is that
it's not a big on/off switch, but subsystem maintainers can just
introduce namespaces when it makes sense.
Thanks,
Martijn
>
> Thanks,
>
> Jessica
I did find an issue with my approach:
On Mon, Jul 16, 2018 at 2:21 PM, Martijn Coenen <[email protected]> wrote:
> The ELF symbols are renamed to include the namespace with an asm label;
> for example, symbol 'usb_stor_suspend' in namespace USB_STORAGE becomes
> 'usb_stor_suspend.USB_STORAGE'. This allows modpost to do namespace
> checking, without having to go through all the effort of parsing ELF and
> reloction records just to get to the struct kernel_symbols.
depmod doesn't like this: if namespaced symbols are built-in to the
kernel, they will appear as 'symbol.NS' in the symbol table, whereas
modules using those symbols just depend on 'symbol'. This will cause
depmod to warn about unknown symbols. I didn't find this previously
because all the exports/imports I tested were done from modules
themselves.
One way to deal with it is to change depmod, but it looks like it
hasn't been changed in ages, and it would also introduce a dependency
on userspaces to update it to avoid these warnings. So, we'd have to
encode the symbol namespace information in another way for modpost to
use. I could just write a separate post-processing tool (much like
genksyms), or perhaps encode the information in a discardable section.
Any other suggestions welcome.
Thanks,
Martijn
>
> On x86_64 I saw no difference in binary size (compression), but at
> runtime this will require a word of memory per export to hold the
> namespace. An alternative could be to store namespaced symbols in their
> own section and use a separate 'struct namespaced_kernel_symbol' for
> that section, at the cost of making the module loader more complex.
>
> Signed-off-by: Martijn Coenen <[email protected]>
> ---
> include/asm-generic/export.h | 2 +-
> include/linux/export.h | 83 +++++++++++++++++++++++++++---------
> include/linux/module.h | 13 ++++++
> kernel/module.c | 79 ++++++++++++++++++++++++++++++++++
> 4 files changed, 156 insertions(+), 21 deletions(-)
>
> diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h
> index 68efb950a918..4c3d1afb702f 100644
> --- a/include/asm-generic/export.h
> +++ b/include/asm-generic/export.h
> @@ -29,7 +29,7 @@
> .section ___ksymtab\sec+\name,"a"
> .balign KSYM_ALIGN
> __ksymtab_\name:
> - __put \val, __kstrtab_\name
> + __put \val, __kstrtab_\name, 0
> .previous
> .section __ksymtab_strings,"a"
> __kstrtab_\name:
> diff --git a/include/linux/export.h b/include/linux/export.h
> index ad6b8e697b27..9f6e70eeb85f 100644
> --- a/include/linux/export.h
> +++ b/include/linux/export.h
> @@ -22,6 +22,11 @@ struct kernel_symbol
> {
> unsigned long value;
> const char *name;
> + const char *namespace;
> +};
> +
> +struct namespace_import {
> + const char *namespace;
> };
>
> #ifdef MODULE
> @@ -54,18 +59,28 @@ extern struct module __this_module;
> #define __CRC_SYMBOL(sym, sec)
> #endif
>
> +#define NS_SEPARATOR "."
> +
> +#define MODULE_IMPORT_NS(ns) \
> + static const struct namespace_import __knsimport_##ns \
> + asm("__knsimport_" #ns) \
> + __attribute__((section("__knsimport"), used)) \
> + = { #ns }
> +
> /* For every exported symbol, place a struct in the __ksymtab section */
> -#define ___EXPORT_SYMBOL(sym, sec) \
> +#define ___EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2) \
> extern typeof(sym) sym; \
> __CRC_SYMBOL(sym, sec) \
> - static const char __kstrtab_##sym[] \
> + static const char __kstrtab_##sym##nspost[] \
> __attribute__((section("__ksymtab_strings"), aligned(1))) \
> = #sym; \
> - static const struct kernel_symbol __ksymtab_##sym \
> + static const struct kernel_symbol __ksymtab_##sym##nspost \
> + asm("__ksymtab_" #sym nspost2) \
> __used \
> - __attribute__((section("___ksymtab" sec "+" #sym), used)) \
> + __attribute__((section("___ksymtab" sec "+" #sym #nspost))) \
> + __attribute__((used)) \
> __attribute__((aligned(sizeof(void *)))) \
> - = { (unsigned long)&sym, __kstrtab_##sym }
> + = { (unsigned long)&sym, __kstrtab_##sym##nspost, ns }
>
> #if defined(__KSYM_DEPS__)
>
> @@ -76,52 +91,80 @@ extern struct module __this_module;
> * system filters out from the preprocessor output (see ksym_dep_filter
> * in scripts/Kbuild.include).
> */
> -#define __EXPORT_SYMBOL(sym, sec) === __KSYM_##sym ===
> +#define __EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2) === __KSYM_##sym ===
>
> #elif defined(CONFIG_TRIM_UNUSED_KSYMS)
>
> #include <generated/autoksyms.h>
>
> -#define __EXPORT_SYMBOL(sym, sec) \
> - __cond_export_sym(sym, sec, __is_defined(__KSYM_##sym))
> -#define __cond_export_sym(sym, sec, conf) \
> - ___cond_export_sym(sym, sec, conf)
> -#define ___cond_export_sym(sym, sec, enabled) \
> - __cond_export_sym_##enabled(sym, sec)
> -#define __cond_export_sym_1(sym, sec) ___EXPORT_SYMBOL(sym, sec)
> -#define __cond_export_sym_0(sym, sec) /* nothing */
> +#define __EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2) \
> + __cond_export_sym(sym, sec, ns, nspost, nspost2, \
> + __is_defined(__KSYM_##sym))
> +#define __cond_export_sym(sym, sec, ns, nspost, nspost2, conf) \
> + ___cond_export_sym(sym, sec, ns, nspost, nspost2, conf)
> +#define ___cond_export_sym(sym, sec, ns, nspost, nspost2, enabled) \
> + __cond_export_sym_##enabled(sym, sec, ns, nspost, nspost2)
> +#define __cond_export_sym_1(sym, sec, ns, nspost, nspost2) \
> + ___EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2)
> +#define __cond_export_sym_0(sym, sec, ns, nspost, nspost2) /* nothing */
>
> #else
> #define __EXPORT_SYMBOL ___EXPORT_SYMBOL
> #endif
>
> #define EXPORT_SYMBOL(sym) \
> - __EXPORT_SYMBOL(sym, "")
> + __EXPORT_SYMBOL(sym, "", NULL, ,)
>
> #define EXPORT_SYMBOL_GPL(sym) \
> - __EXPORT_SYMBOL(sym, "_gpl")
> + __EXPORT_SYMBOL(sym, "_gpl", NULL, ,)
>
> #define EXPORT_SYMBOL_GPL_FUTURE(sym) \
> - __EXPORT_SYMBOL(sym, "_gpl_future")
> + __EXPORT_SYMBOL(sym, "_gpl_future", NULL, ,)
> +
> +#define EXPORT_SYMBOL_NS(sym, ns) \
> + __EXPORT_SYMBOL(sym, "", #ns, __##ns, NS_SEPARATOR #ns)
> +
> +#define EXPORT_SYMBOL_NS_GPL(sym, ns) \
> + __EXPORT_SYMBOL(sym, "_gpl", #ns, __##ns, NS_SEPARATOR #ns)
>
> #ifdef CONFIG_UNUSED_SYMBOLS
> -#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused")
> -#define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl")
> +#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused", , ,)
> +#define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl", , ,)
> #else
> #define EXPORT_UNUSED_SYMBOL(sym)
> #define EXPORT_UNUSED_SYMBOL_GPL(sym)
> #endif
>
> -#endif /* __GENKSYMS__ */
> +#endif /* __KERNEL__ && !__GENKSYMS__ */
> +
> +#if defined(__GENKSYMS__)
> +/*
> + * When we're running genksyms, ignore the namespace and make the _NS
> + * variants look like the normal ones. There are two reasons for this:
> + * 1) In the normal definition of EXPORT_SYMBOL_NS, the 'ns' macro
> + * argument is itself not expanded because it's always tokenized or
> + * concatenated; but when running genksyms, a blank definition of the
> + * macro does allow the argument to be expanded; if a namespace
> + * happens to collide with a #define, this can cause issues.
> + * 2) There's no need to modify genksyms to deal with the _NS variants
> + */
> +#define EXPORT_SYMBOL_NS(sym, ns) \
> + EXPORT_SYMBOL(sym)
> +#define EXPORT_SYMBOL_NS_GPL(sym, ns) \
> + EXPORT_SYMBOL_GPL(sym)
> +#endif
>
> #else /* !CONFIG_MODULES... */
>
> #define EXPORT_SYMBOL(sym)
> +#define EXPORT_SYMBOL_NS(sym, ns)
> +#define EXPORT_SYMBOL_NS_GPL(sym, ns)
> #define EXPORT_SYMBOL_GPL(sym)
> #define EXPORT_SYMBOL_GPL_FUTURE(sym)
> #define EXPORT_UNUSED_SYMBOL(sym)
> #define EXPORT_UNUSED_SYMBOL_GPL(sym)
>
> +#define MODULE_IMPORT_NS(ns)
> #endif /* CONFIG_MODULES */
> #endif /* !__ASSEMBLY__ */
>
> diff --git a/include/linux/module.h b/include/linux/module.h
> index d44df9b2c131..afab4e8fa188 100644
> --- a/include/linux/module.h
> +++ b/include/linux/module.h
> @@ -268,6 +268,12 @@ void *__symbol_get(const char *symbol);
> void *__symbol_get_gpl(const char *symbol);
> #define symbol_get(x) ((typeof(&x))(__symbol_get(VMLINUX_SYMBOL_STR(x))))
>
> +/* namespace dependencies of the module */
> +struct module_ns_dep {
> + struct list_head ns_dep;
> + const char *namespace;
> +};
> +
> /* modules using other modules: kdb wants to see this. */
> struct module_use {
> struct list_head source_list;
> @@ -359,6 +365,13 @@ struct module {
> const struct kernel_symbol *gpl_syms;
> const s32 *gpl_crcs;
>
> + /* Namespace imports */
> + unsigned int num_ns_imports;
> + const struct namespace_import *ns_imports;
> +
> + /* Namespace dependencies */
> + struct list_head ns_dependencies;
> +
> #ifdef CONFIG_UNUSED_SYMBOLS
> /* unused exported symbols. */
> const struct kernel_symbol *unused_syms;
> diff --git a/kernel/module.c b/kernel/module.c
> index f475f30eed8c..63de0fe849f9 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -1166,6 +1166,51 @@ static inline int module_unload_init(struct module *mod)
> }
> #endif /* CONFIG_MODULE_UNLOAD */
>
> +static bool module_has_ns_dependency(struct module *mod, const char *ns)
> +{
> + struct module_ns_dep *ns_dep;
> +
> + list_for_each_entry(ns_dep, &mod->ns_dependencies, ns_dep) {
> + if (strcmp(ns_dep->namespace, ns) == 0)
> + return true;
> + }
> +
> + return false;
> +}
> +
> +static int add_module_ns_dependency(struct module *mod, const char *ns)
> +{
> + struct module_ns_dep *ns_dep;
> +
> + if (module_has_ns_dependency(mod, ns))
> + return 0;
> +
> + ns_dep = kmalloc(sizeof(*ns_dep), GFP_ATOMIC);
> + if (!ns_dep)
> + return -ENOMEM;
> +
> + ns_dep->namespace = ns;
> +
> + list_add(&ns_dep->ns_dep, &mod->ns_dependencies);
> +
> + return 0;
> +}
> +
> +static bool module_imports_ns(struct module *mod, const char *ns)
> +{
> + size_t i;
> +
> + if (!ns)
> + return true;
> +
> + for (i = 0; i < mod->num_ns_imports; ++i) {
> + if (!strcmp(mod->ns_imports[i].namespace, ns))
> + return true;
> + }
> +
> + return false;
> +}
> +
> static size_t module_flags_taint(struct module *mod, char *buf)
> {
> size_t l = 0;
> @@ -1415,6 +1460,18 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
> goto getname;
> }
>
> + /*
> + * We can't yet verify that the module actually imports this
> + * namespace, because the imports themselves are only available
> + * after processing the symbol table and doing relocation; so
> + * instead just record the dependency and check later.
> + */
> + if (sym->namespace) {
> + err = add_module_ns_dependency(mod, sym->namespace);
> + if (err)
> + sym = ERR_PTR(err);
> + }
> +
> getname:
> /* We must make copy under the lock if we failed to get ref. */
> strncpy(ownername, module_name(owner), MODULE_NAME_LEN);
> @@ -3061,6 +3118,11 @@ static int find_module_sections(struct module *mod, struct load_info *info)
> sizeof(*mod->gpl_syms),
> &mod->num_gpl_syms);
> mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
> +
> + mod->ns_imports = section_objs(info, "__knsimport",
> + sizeof(*mod->ns_imports),
> + &mod->num_ns_imports);
> +
> mod->gpl_future_syms = section_objs(info,
> "__ksymtab_gpl_future",
> sizeof(*mod->gpl_future_syms),
> @@ -3381,6 +3443,19 @@ static int post_relocation(struct module *mod, const struct load_info *info)
> return module_finalize(info->hdr, info->sechdrs, mod);
> }
>
> +static void verify_namespace_dependencies(struct module *mod)
> +{
> + struct module_ns_dep *ns_dep;
> +
> + list_for_each_entry(ns_dep, &mod->ns_dependencies, ns_dep) {
> + if (!module_imports_ns(mod, ns_dep->namespace)) {
> + pr_warn("%s: module uses symbols from namespace %s,"
> + " but does not import it.\n",
> + mod->name, ns_dep->namespace);
> + }
> + }
> +}
> +
> /* Is this module of this name done loading? No locks held. */
> static bool finished_loading(const char *name)
> {
> @@ -3682,6 +3757,8 @@ static int load_module(struct load_info *info, const char __user *uargs,
> if (err)
> goto free_module;
>
> + INIT_LIST_HEAD(&mod->ns_dependencies);
> +
> #ifdef CONFIG_MODULE_SIG
> mod->sig_ok = info->sig_ok;
> if (!mod->sig_ok) {
> @@ -3730,6 +3807,8 @@ static int load_module(struct load_info *info, const char __user *uargs,
> if (err < 0)
> goto free_modinfo;
>
> + verify_namespace_dependencies(mod);
> +
> flush_module_icache(mod);
>
> /* Now copy in args */
> --
> 2.18.0.203.gfac676dfb9-goog
>
Hi Arnd,
On Mon, Jul 23, 2018 at 4:28 PM, Arnd Bergmann <[email protected]> wrote:
> This looks nice. I don't want to overload you with additional
> requests, but it might be good to think about how this can
> be taken further, if we want to actually convert large
> parts of the kernel to it.
No worries about overloading, I'm happy with all feedback to make this better.
> I have two ideas:
>
> - It would be nice to have a simple mechanism in Kconfig
> to put all symbols in a module into a namespace that is
> derived from KBUILD_MODNAME, to avoid having to
> annotate every symbol separately. This could be similar
> to how we ended up dealing with EXPORT_NO_SYMBOLS
> in the linux-2.4 days, with the goal of eventually having
> a namespace for each symbol. Similarly, we could pass
> a number of default namespaces through the Makefile,
> e.g. if we have a directory that has lots of drivers that all
> import the symbols from a common subsystem module.
I'm hinging on two thoughts here; I really like it because it
obviously reduces work and makes this easier to use. On the other
hand, you now have to look in multiple places to see if a symbol is
exported to a namespace/imported from a module. Perhaps it depends on
how coarse-grained the namespaces end up being. Either way, I think it
would be pretty easy to cook up patches for this.
>
> - If this is possible to implement, it would be great to have
> a way to limit the globally visible symbols in a module
> to the ones that are explicitly exported even when a that
> module is built-in rather than loadable. Not sure how this
> is best done though. A couple of things can be done with
> objcopy, or possibly by reintroducing partial linking (which
> was removed not too long ago).
If I understand you correctly, this is orthogonal to symbol
namespaces, right? Though I think there is value in doing the same
thing for symbol namespaces: right now, the only way to find out if
all modules correctly import a symbol exported to a namespace is to
run an 'allmodconfig'; not having to do that would be a win. Being
able to do the same thing for the exported symbols in the global
namespace is very similar. So yeah, I think this is a good idea and
will look into this more.
Do you think these things should be a part of these series, or can it
be a follow-up?
Thanks,
Martijn
>
> Arnd
On Tue, Jul 24, 2018 at 10:09 AM, Martijn Coenen <[email protected]> wrote:
> Hi Arnd,
>
> On Mon, Jul 23, 2018 at 4:28 PM, Arnd Bergmann <[email protected]> wrote:
>> This looks nice. I don't want to overload you with additional
>> requests, but it might be good to think about how this can
>> be taken further, if we want to actually convert large
>> parts of the kernel to it.
>
> No worries about overloading, I'm happy with all feedback to make this better.
>
>> I have two ideas:
>>
>> - It would be nice to have a simple mechanism in Kconfig
>> to put all symbols in a module into a namespace that is
>> derived from KBUILD_MODNAME, to avoid having to
>> annotate every symbol separately. This could be similar
>> to how we ended up dealing with EXPORT_NO_SYMBOLS
>> in the linux-2.4 days, with the goal of eventually having
>> a namespace for each symbol. Similarly, we could pass
>> a number of default namespaces through the Makefile,
>> e.g. if we have a directory that has lots of drivers that all
>> import the symbols from a common subsystem module.
>
> I'm hinging on two thoughts here; I really like it because it
> obviously reduces work and makes this easier to use. On the other
> hand, you now have to look in multiple places to see if a symbol is
> exported to a namespace/imported from a module. Perhaps it depends on
> how coarse-grained the namespaces end up being. Either way, I think it
> would be pretty easy to cook up patches for this.
Ok, maybe try it and see where we get with it?
>> - If this is possible to implement, it would be great to have
>> a way to limit the globally visible symbols in a module
>> to the ones that are explicitly exported even when a that
>> module is built-in rather than loadable. Not sure how this
>> is best done though. A couple of things can be done with
>> objcopy, or possibly by reintroducing partial linking (which
>> was removed not too long ago).
>
> If I understand you correctly, this is orthogonal to symbol
> namespaces, right?
Right, the only connection here is that both try to limit the
scope of which symbols are available where. This can definitely
be done without symbol namespaces. The implementation I
had in mind with objcopy might end up using the same
KBUILD_MODNAME as a prefix for internal symbols (which
are not exported to modules), but that is a different problem.
Another related area is the question what happens to symbols
that we want to share between two built-in parts of the kernel
without exporting them to modules. E.g. if we might want to
put all of vfs into one built-in module and make its symbols
private to that module, while all of the mm subsystem is in a
separate built-in module. The symbols that are needed for
communicating between the two could simply be exported
with EXPORT_SYMBOL_GPL(), but we that would open the
surface to loadable modules that can't access them today.
Using namespaces could solve that problem by limiting the
scope in another way, or we could come up with a different
method to annotate them, such as using the gcc visibility
attributes.
> Do you think these things should be a part of these series, or can it
> be a follow-up?
If you think you can do the first thing easily, I'd say we should
try to come up with an idea of where we want to take this in
the long run. For limiting the scope of global symbols, that may
well be a much bigger task to do upfront, so unless you have an
idea for how to do that, maybe keep it in mind but let's not make
it a dependency.
Arnd
+++ Martijn Coenen [24/07/18 09:56 +0200]:
>I did find an issue with my approach:
>
>On Mon, Jul 16, 2018 at 2:21 PM, Martijn Coenen <[email protected]> wrote:
>> The ELF symbols are renamed to include the namespace with an asm label;
>> for example, symbol 'usb_stor_suspend' in namespace USB_STORAGE becomes
>> 'usb_stor_suspend.USB_STORAGE'. This allows modpost to do namespace
>> checking, without having to go through all the effort of parsing ELF and
>> reloction records just to get to the struct kernel_symbols.
>
>depmod doesn't like this: if namespaced symbols are built-in to the
>kernel, they will appear as 'symbol.NS' in the symbol table, whereas
>modules using those symbols just depend on 'symbol'. This will cause
>depmod to warn about unknown symbols. I didn't find this previously
>because all the exports/imports I tested were done from modules
>themselves.
>
>One way to deal with it is to change depmod, but it looks like it
>hasn't been changed in ages, and it would also introduce a dependency
>on userspaces to update it to avoid these warnings. So, we'd have to
>encode the symbol namespace information in another way for modpost to
>use. I could just write a separate post-processing tool (much like
>genksyms), or perhaps encode the information in a discardable section.
>Any other suggestions welcome.
This seems to be because depmod uses System.map as a source for kernel
symbols and scans for only the ones prefixed with "__ksymtab" to find
the exported ones - and those happen to use the '.' to mark the
namespace it belongs to. It strips that prefix and uses the remainder
as the actual symbol name. To fix that it'd have to strip the
namespace suffix in the symbol name as well.
Just scanning the depmod source code, it seems really trivial to just
have depmod accommodate the new symbol name format. Adding Lucas (kmod
maintainer) to CC.
Thanks,
Jessica
>
>>
>> On x86_64 I saw no difference in binary size (compression), but at
>> runtime this will require a word of memory per export to hold the
>> namespace. An alternative could be to store namespaced symbols in their
>> own section and use a separate 'struct namespaced_kernel_symbol' for
>> that section, at the cost of making the module loader more complex.
>>
>> Signed-off-by: Martijn Coenen <[email protected]>
>> ---
>> include/asm-generic/export.h | 2 +-
>> include/linux/export.h | 83 +++++++++++++++++++++++++++---------
>> include/linux/module.h | 13 ++++++
>> kernel/module.c | 79 ++++++++++++++++++++++++++++++++++
>> 4 files changed, 156 insertions(+), 21 deletions(-)
>>
>> diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h
>> index 68efb950a918..4c3d1afb702f 100644
>> --- a/include/asm-generic/export.h
>> +++ b/include/asm-generic/export.h
>> @@ -29,7 +29,7 @@
>> .section ___ksymtab\sec+\name,"a"
>> .balign KSYM_ALIGN
>> __ksymtab_\name:
>> - __put \val, __kstrtab_\name
>> + __put \val, __kstrtab_\name, 0
>> .previous
>> .section __ksymtab_strings,"a"
>> __kstrtab_\name:
>> diff --git a/include/linux/export.h b/include/linux/export.h
>> index ad6b8e697b27..9f6e70eeb85f 100644
>> --- a/include/linux/export.h
>> +++ b/include/linux/export.h
>> @@ -22,6 +22,11 @@ struct kernel_symbol
>> {
>> unsigned long value;
>> const char *name;
>> + const char *namespace;
>> +};
>> +
>> +struct namespace_import {
>> + const char *namespace;
>> };
>>
>> #ifdef MODULE
>> @@ -54,18 +59,28 @@ extern struct module __this_module;
>> #define __CRC_SYMBOL(sym, sec)
>> #endif
>>
>> +#define NS_SEPARATOR "."
>> +
>> +#define MODULE_IMPORT_NS(ns) \
>> + static const struct namespace_import __knsimport_##ns \
>> + asm("__knsimport_" #ns) \
>> + __attribute__((section("__knsimport"), used)) \
>> + = { #ns }
>> +
>> /* For every exported symbol, place a struct in the __ksymtab section */
>> -#define ___EXPORT_SYMBOL(sym, sec) \
>> +#define ___EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2) \
>> extern typeof(sym) sym; \
>> __CRC_SYMBOL(sym, sec) \
>> - static const char __kstrtab_##sym[] \
>> + static const char __kstrtab_##sym##nspost[] \
>> __attribute__((section("__ksymtab_strings"), aligned(1))) \
>> = #sym; \
>> - static const struct kernel_symbol __ksymtab_##sym \
>> + static const struct kernel_symbol __ksymtab_##sym##nspost \
>> + asm("__ksymtab_" #sym nspost2) \
>> __used \
>> - __attribute__((section("___ksymtab" sec "+" #sym), used)) \
>> + __attribute__((section("___ksymtab" sec "+" #sym #nspost))) \
>> + __attribute__((used)) \
>> __attribute__((aligned(sizeof(void *)))) \
>> - = { (unsigned long)&sym, __kstrtab_##sym }
>> + = { (unsigned long)&sym, __kstrtab_##sym##nspost, ns }
>>
>> #if defined(__KSYM_DEPS__)
>>
>> @@ -76,52 +91,80 @@ extern struct module __this_module;
>> * system filters out from the preprocessor output (see ksym_dep_filter
>> * in scripts/Kbuild.include).
>> */
>> -#define __EXPORT_SYMBOL(sym, sec) === __KSYM_##sym ===
>> +#define __EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2) === __KSYM_##sym ===
>>
>> #elif defined(CONFIG_TRIM_UNUSED_KSYMS)
>>
>> #include <generated/autoksyms.h>
>>
>> -#define __EXPORT_SYMBOL(sym, sec) \
>> - __cond_export_sym(sym, sec, __is_defined(__KSYM_##sym))
>> -#define __cond_export_sym(sym, sec, conf) \
>> - ___cond_export_sym(sym, sec, conf)
>> -#define ___cond_export_sym(sym, sec, enabled) \
>> - __cond_export_sym_##enabled(sym, sec)
>> -#define __cond_export_sym_1(sym, sec) ___EXPORT_SYMBOL(sym, sec)
>> -#define __cond_export_sym_0(sym, sec) /* nothing */
>> +#define __EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2) \
>> + __cond_export_sym(sym, sec, ns, nspost, nspost2, \
>> + __is_defined(__KSYM_##sym))
>> +#define __cond_export_sym(sym, sec, ns, nspost, nspost2, conf) \
>> + ___cond_export_sym(sym, sec, ns, nspost, nspost2, conf)
>> +#define ___cond_export_sym(sym, sec, ns, nspost, nspost2, enabled) \
>> + __cond_export_sym_##enabled(sym, sec, ns, nspost, nspost2)
>> +#define __cond_export_sym_1(sym, sec, ns, nspost, nspost2) \
>> + ___EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2)
>> +#define __cond_export_sym_0(sym, sec, ns, nspost, nspost2) /* nothing */
>>
>> #else
>> #define __EXPORT_SYMBOL ___EXPORT_SYMBOL
>> #endif
>>
>> #define EXPORT_SYMBOL(sym) \
>> - __EXPORT_SYMBOL(sym, "")
>> + __EXPORT_SYMBOL(sym, "", NULL, ,)
>>
>> #define EXPORT_SYMBOL_GPL(sym) \
>> - __EXPORT_SYMBOL(sym, "_gpl")
>> + __EXPORT_SYMBOL(sym, "_gpl", NULL, ,)
>>
>> #define EXPORT_SYMBOL_GPL_FUTURE(sym) \
>> - __EXPORT_SYMBOL(sym, "_gpl_future")
>> + __EXPORT_SYMBOL(sym, "_gpl_future", NULL, ,)
>> +
>> +#define EXPORT_SYMBOL_NS(sym, ns) \
>> + __EXPORT_SYMBOL(sym, "", #ns, __##ns, NS_SEPARATOR #ns)
>> +
>> +#define EXPORT_SYMBOL_NS_GPL(sym, ns) \
>> + __EXPORT_SYMBOL(sym, "_gpl", #ns, __##ns, NS_SEPARATOR #ns)
>>
>> #ifdef CONFIG_UNUSED_SYMBOLS
>> -#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused")
>> -#define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl")
>> +#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused", , ,)
>> +#define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl", , ,)
>> #else
>> #define EXPORT_UNUSED_SYMBOL(sym)
>> #define EXPORT_UNUSED_SYMBOL_GPL(sym)
>> #endif
>>
>> -#endif /* __GENKSYMS__ */
>> +#endif /* __KERNEL__ && !__GENKSYMS__ */
>> +
>> +#if defined(__GENKSYMS__)
>> +/*
>> + * When we're running genksyms, ignore the namespace and make the _NS
>> + * variants look like the normal ones. There are two reasons for this:
>> + * 1) In the normal definition of EXPORT_SYMBOL_NS, the 'ns' macro
>> + * argument is itself not expanded because it's always tokenized or
>> + * concatenated; but when running genksyms, a blank definition of the
>> + * macro does allow the argument to be expanded; if a namespace
>> + * happens to collide with a #define, this can cause issues.
>> + * 2) There's no need to modify genksyms to deal with the _NS variants
>> + */
>> +#define EXPORT_SYMBOL_NS(sym, ns) \
>> + EXPORT_SYMBOL(sym)
>> +#define EXPORT_SYMBOL_NS_GPL(sym, ns) \
>> + EXPORT_SYMBOL_GPL(sym)
>> +#endif
>>
>> #else /* !CONFIG_MODULES... */
>>
>> #define EXPORT_SYMBOL(sym)
>> +#define EXPORT_SYMBOL_NS(sym, ns)
>> +#define EXPORT_SYMBOL_NS_GPL(sym, ns)
>> #define EXPORT_SYMBOL_GPL(sym)
>> #define EXPORT_SYMBOL_GPL_FUTURE(sym)
>> #define EXPORT_UNUSED_SYMBOL(sym)
>> #define EXPORT_UNUSED_SYMBOL_GPL(sym)
>>
>> +#define MODULE_IMPORT_NS(ns)
>> #endif /* CONFIG_MODULES */
>> #endif /* !__ASSEMBLY__ */
>>
>> diff --git a/include/linux/module.h b/include/linux/module.h
>> index d44df9b2c131..afab4e8fa188 100644
>> --- a/include/linux/module.h
>> +++ b/include/linux/module.h
>> @@ -268,6 +268,12 @@ void *__symbol_get(const char *symbol);
>> void *__symbol_get_gpl(const char *symbol);
>> #define symbol_get(x) ((typeof(&x))(__symbol_get(VMLINUX_SYMBOL_STR(x))))
>>
>> +/* namespace dependencies of the module */
>> +struct module_ns_dep {
>> + struct list_head ns_dep;
>> + const char *namespace;
>> +};
>> +
>> /* modules using other modules: kdb wants to see this. */
>> struct module_use {
>> struct list_head source_list;
>> @@ -359,6 +365,13 @@ struct module {
>> const struct kernel_symbol *gpl_syms;
>> const s32 *gpl_crcs;
>>
>> + /* Namespace imports */
>> + unsigned int num_ns_imports;
>> + const struct namespace_import *ns_imports;
>> +
>> + /* Namespace dependencies */
>> + struct list_head ns_dependencies;
>> +
>> #ifdef CONFIG_UNUSED_SYMBOLS
>> /* unused exported symbols. */
>> const struct kernel_symbol *unused_syms;
>> diff --git a/kernel/module.c b/kernel/module.c
>> index f475f30eed8c..63de0fe849f9 100644
>> --- a/kernel/module.c
>> +++ b/kernel/module.c
>> @@ -1166,6 +1166,51 @@ static inline int module_unload_init(struct module *mod)
>> }
>> #endif /* CONFIG_MODULE_UNLOAD */
>>
>> +static bool module_has_ns_dependency(struct module *mod, const char *ns)
>> +{
>> + struct module_ns_dep *ns_dep;
>> +
>> + list_for_each_entry(ns_dep, &mod->ns_dependencies, ns_dep) {
>> + if (strcmp(ns_dep->namespace, ns) == 0)
>> + return true;
>> + }
>> +
>> + return false;
>> +}
>> +
>> +static int add_module_ns_dependency(struct module *mod, const char *ns)
>> +{
>> + struct module_ns_dep *ns_dep;
>> +
>> + if (module_has_ns_dependency(mod, ns))
>> + return 0;
>> +
>> + ns_dep = kmalloc(sizeof(*ns_dep), GFP_ATOMIC);
>> + if (!ns_dep)
>> + return -ENOMEM;
>> +
>> + ns_dep->namespace = ns;
>> +
>> + list_add(&ns_dep->ns_dep, &mod->ns_dependencies);
>> +
>> + return 0;
>> +}
>> +
>> +static bool module_imports_ns(struct module *mod, const char *ns)
>> +{
>> + size_t i;
>> +
>> + if (!ns)
>> + return true;
>> +
>> + for (i = 0; i < mod->num_ns_imports; ++i) {
>> + if (!strcmp(mod->ns_imports[i].namespace, ns))
>> + return true;
>> + }
>> +
>> + return false;
>> +}
>> +
>> static size_t module_flags_taint(struct module *mod, char *buf)
>> {
>> size_t l = 0;
>> @@ -1415,6 +1460,18 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
>> goto getname;
>> }
>>
>> + /*
>> + * We can't yet verify that the module actually imports this
>> + * namespace, because the imports themselves are only available
>> + * after processing the symbol table and doing relocation; so
>> + * instead just record the dependency and check later.
>> + */
>> + if (sym->namespace) {
>> + err = add_module_ns_dependency(mod, sym->namespace);
>> + if (err)
>> + sym = ERR_PTR(err);
>> + }
>> +
>> getname:
>> /* We must make copy under the lock if we failed to get ref. */
>> strncpy(ownername, module_name(owner), MODULE_NAME_LEN);
>> @@ -3061,6 +3118,11 @@ static int find_module_sections(struct module *mod, struct load_info *info)
>> sizeof(*mod->gpl_syms),
>> &mod->num_gpl_syms);
>> mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
>> +
>> + mod->ns_imports = section_objs(info, "__knsimport",
>> + sizeof(*mod->ns_imports),
>> + &mod->num_ns_imports);
>> +
>> mod->gpl_future_syms = section_objs(info,
>> "__ksymtab_gpl_future",
>> sizeof(*mod->gpl_future_syms),
>> @@ -3381,6 +3443,19 @@ static int post_relocation(struct module *mod, const struct load_info *info)
>> return module_finalize(info->hdr, info->sechdrs, mod);
>> }
>>
>> +static void verify_namespace_dependencies(struct module *mod)
>> +{
>> + struct module_ns_dep *ns_dep;
>> +
>> + list_for_each_entry(ns_dep, &mod->ns_dependencies, ns_dep) {
>> + if (!module_imports_ns(mod, ns_dep->namespace)) {
>> + pr_warn("%s: module uses symbols from namespace %s,"
>> + " but does not import it.\n",
>> + mod->name, ns_dep->namespace);
>> + }
>> + }
>> +}
>> +
>> /* Is this module of this name done loading? No locks held. */
>> static bool finished_loading(const char *name)
>> {
>> @@ -3682,6 +3757,8 @@ static int load_module(struct load_info *info, const char __user *uargs,
>> if (err)
>> goto free_module;
>>
>> + INIT_LIST_HEAD(&mod->ns_dependencies);
>> +
>> #ifdef CONFIG_MODULE_SIG
>> mod->sig_ok = info->sig_ok;
>> if (!mod->sig_ok) {
>> @@ -3730,6 +3807,8 @@ static int load_module(struct load_info *info, const char __user *uargs,
>> if (err < 0)
>> goto free_modinfo;
>>
>> + verify_namespace_dependencies(mod);
>> +
>> flush_module_icache(mod);
>>
>> /* Now copy in args */
>> --
>> 2.18.0.203.gfac676dfb9-goog
>>
On Wed, Jul 25, 2018 at 8:55 AM Jessica Yu <[email protected]> wrote:
>
> +++ Martijn Coenen [24/07/18 09:56 +0200]:
> >I did find an issue with my approach:
> >
> >On Mon, Jul 16, 2018 at 2:21 PM, Martijn Coenen <[email protected]> wrote:
> >> The ELF symbols are renamed to include the namespace with an asm label;
> >> for example, symbol 'usb_stor_suspend' in namespace USB_STORAGE becomes
> >> 'usb_stor_suspend.USB_STORAGE'. This allows modpost to do namespace
> >> checking, without having to go through all the effort of parsing ELF and
> >> reloction records just to get to the struct kernel_symbols.
> >
> >depmod doesn't like this: if namespaced symbols are built-in to the
> >kernel, they will appear as 'symbol.NS' in the symbol table, whereas
> >modules using those symbols just depend on 'symbol'. This will cause
> >depmod to warn about unknown symbols. I didn't find this previously
> >because all the exports/imports I tested were done from modules
> >themselves.
> >
> >One way to deal with it is to change depmod, but it looks like it
> >hasn't been changed in ages, and it would also introduce a dependency
this might be because you are looking to the wrong project
(module-init-tools) rather than kmod that replaced it some years ago?
> >on userspaces to update it to avoid these warnings. So, we'd have to
> >encode the symbol namespace information in another way for modpost to
> >use. I could just write a separate post-processing tool (much like
> >genksyms), or perhaps encode the information in a discardable section.
> >Any other suggestions welcome.
>
> This seems to be because depmod uses System.map as a source for kernel
> symbols and scans for only the ones prefixed with "__ksymtab" to find
> the exported ones - and those happen to use the '.' to mark the
> namespace it belongs to. It strips that prefix and uses the remainder
> as the actual symbol name. To fix that it'd have to strip the
> namespace suffix in the symbol name as well.
>
> Just scanning the depmod source code, it seems really trivial to just
> have depmod accommodate the new symbol name format. Adding Lucas (kmod
> maintainer) to CC.
Yep, that would be easy and allow depmod to be backward compatible
since we would do nothing if the symbol doesn't have the suffix.
As for dependency on a new version, this seems trivial enough to be
backported to previous releases used on distros so even if they are
not rolling they would get a compatible depmod.
CC'ing [email protected] to keep track of this there
thanks
Lucas De Marchi
>
> Thanks,
>
> Jessica
>
> >
> >>
> >> On x86_64 I saw no difference in binary size (compression), but at
> >> runtime this will require a word of memory per export to hold the
> >> namespace. An alternative could be to store namespaced symbols in their
> >> own section and use a separate 'struct namespaced_kernel_symbol' for
> >> that section, at the cost of making the module loader more complex.
> >>
> >> Signed-off-by: Martijn Coenen <[email protected]>
> >> ---
> >> include/asm-generic/export.h | 2 +-
> >> include/linux/export.h | 83 +++++++++++++++++++++++++++---------
> >> include/linux/module.h | 13 ++++++
> >> kernel/module.c | 79 ++++++++++++++++++++++++++++++++++
> >> 4 files changed, 156 insertions(+), 21 deletions(-)
> >>
> >> diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h
> >> index 68efb950a918..4c3d1afb702f 100644
> >> --- a/include/asm-generic/export.h
> >> +++ b/include/asm-generic/export.h
> >> @@ -29,7 +29,7 @@
> >> .section ___ksymtab\sec+\name,"a"
> >> .balign KSYM_ALIGN
> >> __ksymtab_\name:
> >> - __put \val, __kstrtab_\name
> >> + __put \val, __kstrtab_\name, 0
> >> .previous
> >> .section __ksymtab_strings,"a"
> >> __kstrtab_\name:
> >> diff --git a/include/linux/export.h b/include/linux/export.h
> >> index ad6b8e697b27..9f6e70eeb85f 100644
> >> --- a/include/linux/export.h
> >> +++ b/include/linux/export.h
> >> @@ -22,6 +22,11 @@ struct kernel_symbol
> >> {
> >> unsigned long value;
> >> const char *name;
> >> + const char *namespace;
> >> +};
> >> +
> >> +struct namespace_import {
> >> + const char *namespace;
> >> };
> >>
> >> #ifdef MODULE
> >> @@ -54,18 +59,28 @@ extern struct module __this_module;
> >> #define __CRC_SYMBOL(sym, sec)
> >> #endif
> >>
> >> +#define NS_SEPARATOR "."
> >> +
> >> +#define MODULE_IMPORT_NS(ns) \
> >> + static const struct namespace_import __knsimport_##ns \
> >> + asm("__knsimport_" #ns) \
> >> + __attribute__((section("__knsimport"), used)) \
> >> + = { #ns }
> >> +
> >> /* For every exported symbol, place a struct in the __ksymtab section */
> >> -#define ___EXPORT_SYMBOL(sym, sec) \
> >> +#define ___EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2) \
> >> extern typeof(sym) sym; \
> >> __CRC_SYMBOL(sym, sec) \
> >> - static const char __kstrtab_##sym[] \
> >> + static const char __kstrtab_##sym##nspost[] \
> >> __attribute__((section("__ksymtab_strings"), aligned(1))) \
> >> = #sym; \
> >> - static const struct kernel_symbol __ksymtab_##sym \
> >> + static const struct kernel_symbol __ksymtab_##sym##nspost \
> >> + asm("__ksymtab_" #sym nspost2) \
> >> __used \
> >> - __attribute__((section("___ksymtab" sec "+" #sym), used)) \
> >> + __attribute__((section("___ksymtab" sec "+" #sym #nspost))) \
> >> + __attribute__((used)) \
> >> __attribute__((aligned(sizeof(void *)))) \
> >> - = { (unsigned long)&sym, __kstrtab_##sym }
> >> + = { (unsigned long)&sym, __kstrtab_##sym##nspost, ns }
> >>
> >> #if defined(__KSYM_DEPS__)
> >>
> >> @@ -76,52 +91,80 @@ extern struct module __this_module;
> >> * system filters out from the preprocessor output (see ksym_dep_filter
> >> * in scripts/Kbuild.include).
> >> */
> >> -#define __EXPORT_SYMBOL(sym, sec) === __KSYM_##sym ===
> >> +#define __EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2) === __KSYM_##sym ===
> >>
> >> #elif defined(CONFIG_TRIM_UNUSED_KSYMS)
> >>
> >> #include <generated/autoksyms.h>
> >>
> >> -#define __EXPORT_SYMBOL(sym, sec) \
> >> - __cond_export_sym(sym, sec, __is_defined(__KSYM_##sym))
> >> -#define __cond_export_sym(sym, sec, conf) \
> >> - ___cond_export_sym(sym, sec, conf)
> >> -#define ___cond_export_sym(sym, sec, enabled) \
> >> - __cond_export_sym_##enabled(sym, sec)
> >> -#define __cond_export_sym_1(sym, sec) ___EXPORT_SYMBOL(sym, sec)
> >> -#define __cond_export_sym_0(sym, sec) /* nothing */
> >> +#define __EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2) \
> >> + __cond_export_sym(sym, sec, ns, nspost, nspost2, \
> >> + __is_defined(__KSYM_##sym))
> >> +#define __cond_export_sym(sym, sec, ns, nspost, nspost2, conf) \
> >> + ___cond_export_sym(sym, sec, ns, nspost, nspost2, conf)
> >> +#define ___cond_export_sym(sym, sec, ns, nspost, nspost2, enabled) \
> >> + __cond_export_sym_##enabled(sym, sec, ns, nspost, nspost2)
> >> +#define __cond_export_sym_1(sym, sec, ns, nspost, nspost2) \
> >> + ___EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2)
> >> +#define __cond_export_sym_0(sym, sec, ns, nspost, nspost2) /* nothing */
> >>
> >> #else
> >> #define __EXPORT_SYMBOL ___EXPORT_SYMBOL
> >> #endif
> >>
> >> #define EXPORT_SYMBOL(sym) \
> >> - __EXPORT_SYMBOL(sym, "")
> >> + __EXPORT_SYMBOL(sym, "", NULL, ,)
> >>
> >> #define EXPORT_SYMBOL_GPL(sym) \
> >> - __EXPORT_SYMBOL(sym, "_gpl")
> >> + __EXPORT_SYMBOL(sym, "_gpl", NULL, ,)
> >>
> >> #define EXPORT_SYMBOL_GPL_FUTURE(sym) \
> >> - __EXPORT_SYMBOL(sym, "_gpl_future")
> >> + __EXPORT_SYMBOL(sym, "_gpl_future", NULL, ,)
> >> +
> >> +#define EXPORT_SYMBOL_NS(sym, ns) \
> >> + __EXPORT_SYMBOL(sym, "", #ns, __##ns, NS_SEPARATOR #ns)
> >> +
> >> +#define EXPORT_SYMBOL_NS_GPL(sym, ns) \
> >> + __EXPORT_SYMBOL(sym, "_gpl", #ns, __##ns, NS_SEPARATOR #ns)
> >>
> >> #ifdef CONFIG_UNUSED_SYMBOLS
> >> -#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused")
> >> -#define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl")
> >> +#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused", , ,)
> >> +#define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl", , ,)
> >> #else
> >> #define EXPORT_UNUSED_SYMBOL(sym)
> >> #define EXPORT_UNUSED_SYMBOL_GPL(sym)
> >> #endif
> >>
> >> -#endif /* __GENKSYMS__ */
> >> +#endif /* __KERNEL__ && !__GENKSYMS__ */
> >> +
> >> +#if defined(__GENKSYMS__)
> >> +/*
> >> + * When we're running genksyms, ignore the namespace and make the _NS
> >> + * variants look like the normal ones. There are two reasons for this:
> >> + * 1) In the normal definition of EXPORT_SYMBOL_NS, the 'ns' macro
> >> + * argument is itself not expanded because it's always tokenized or
> >> + * concatenated; but when running genksyms, a blank definition of the
> >> + * macro does allow the argument to be expanded; if a namespace
> >> + * happens to collide with a #define, this can cause issues.
> >> + * 2) There's no need to modify genksyms to deal with the _NS variants
> >> + */
> >> +#define EXPORT_SYMBOL_NS(sym, ns) \
> >> + EXPORT_SYMBOL(sym)
> >> +#define EXPORT_SYMBOL_NS_GPL(sym, ns) \
> >> + EXPORT_SYMBOL_GPL(sym)
> >> +#endif
> >>
> >> #else /* !CONFIG_MODULES... */
> >>
> >> #define EXPORT_SYMBOL(sym)
> >> +#define EXPORT_SYMBOL_NS(sym, ns)
> >> +#define EXPORT_SYMBOL_NS_GPL(sym, ns)
> >> #define EXPORT_SYMBOL_GPL(sym)
> >> #define EXPORT_SYMBOL_GPL_FUTURE(sym)
> >> #define EXPORT_UNUSED_SYMBOL(sym)
> >> #define EXPORT_UNUSED_SYMBOL_GPL(sym)
> >>
> >> +#define MODULE_IMPORT_NS(ns)
> >> #endif /* CONFIG_MODULES */
> >> #endif /* !__ASSEMBLY__ */
> >>
> >> diff --git a/include/linux/module.h b/include/linux/module.h
> >> index d44df9b2c131..afab4e8fa188 100644
> >> --- a/include/linux/module.h
> >> +++ b/include/linux/module.h
> >> @@ -268,6 +268,12 @@ void *__symbol_get(const char *symbol);
> >> void *__symbol_get_gpl(const char *symbol);
> >> #define symbol_get(x) ((typeof(&x))(__symbol_get(VMLINUX_SYMBOL_STR(x))))
> >>
> >> +/* namespace dependencies of the module */
> >> +struct module_ns_dep {
> >> + struct list_head ns_dep;
> >> + const char *namespace;
> >> +};
> >> +
> >> /* modules using other modules: kdb wants to see this. */
> >> struct module_use {
> >> struct list_head source_list;
> >> @@ -359,6 +365,13 @@ struct module {
> >> const struct kernel_symbol *gpl_syms;
> >> const s32 *gpl_crcs;
> >>
> >> + /* Namespace imports */
> >> + unsigned int num_ns_imports;
> >> + const struct namespace_import *ns_imports;
> >> +
> >> + /* Namespace dependencies */
> >> + struct list_head ns_dependencies;
> >> +
> >> #ifdef CONFIG_UNUSED_SYMBOLS
> >> /* unused exported symbols. */
> >> const struct kernel_symbol *unused_syms;
> >> diff --git a/kernel/module.c b/kernel/module.c
> >> index f475f30eed8c..63de0fe849f9 100644
> >> --- a/kernel/module.c
> >> +++ b/kernel/module.c
> >> @@ -1166,6 +1166,51 @@ static inline int module_unload_init(struct module *mod)
> >> }
> >> #endif /* CONFIG_MODULE_UNLOAD */
> >>
> >> +static bool module_has_ns_dependency(struct module *mod, const char *ns)
> >> +{
> >> + struct module_ns_dep *ns_dep;
> >> +
> >> + list_for_each_entry(ns_dep, &mod->ns_dependencies, ns_dep) {
> >> + if (strcmp(ns_dep->namespace, ns) == 0)
> >> + return true;
> >> + }
> >> +
> >> + return false;
> >> +}
> >> +
> >> +static int add_module_ns_dependency(struct module *mod, const char *ns)
> >> +{
> >> + struct module_ns_dep *ns_dep;
> >> +
> >> + if (module_has_ns_dependency(mod, ns))
> >> + return 0;
> >> +
> >> + ns_dep = kmalloc(sizeof(*ns_dep), GFP_ATOMIC);
> >> + if (!ns_dep)
> >> + return -ENOMEM;
> >> +
> >> + ns_dep->namespace = ns;
> >> +
> >> + list_add(&ns_dep->ns_dep, &mod->ns_dependencies);
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static bool module_imports_ns(struct module *mod, const char *ns)
> >> +{
> >> + size_t i;
> >> +
> >> + if (!ns)
> >> + return true;
> >> +
> >> + for (i = 0; i < mod->num_ns_imports; ++i) {
> >> + if (!strcmp(mod->ns_imports[i].namespace, ns))
> >> + return true;
> >> + }
> >> +
> >> + return false;
> >> +}
> >> +
> >> static size_t module_flags_taint(struct module *mod, char *buf)
> >> {
> >> size_t l = 0;
> >> @@ -1415,6 +1460,18 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
> >> goto getname;
> >> }
> >>
> >> + /*
> >> + * We can't yet verify that the module actually imports this
> >> + * namespace, because the imports themselves are only available
> >> + * after processing the symbol table and doing relocation; so
> >> + * instead just record the dependency and check later.
> >> + */
> >> + if (sym->namespace) {
> >> + err = add_module_ns_dependency(mod, sym->namespace);
> >> + if (err)
> >> + sym = ERR_PTR(err);
> >> + }
> >> +
> >> getname:
> >> /* We must make copy under the lock if we failed to get ref. */
> >> strncpy(ownername, module_name(owner), MODULE_NAME_LEN);
> >> @@ -3061,6 +3118,11 @@ static int find_module_sections(struct module *mod, struct load_info *info)
> >> sizeof(*mod->gpl_syms),
> >> &mod->num_gpl_syms);
> >> mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
> >> +
> >> + mod->ns_imports = section_objs(info, "__knsimport",
> >> + sizeof(*mod->ns_imports),
> >> + &mod->num_ns_imports);
> >> +
> >> mod->gpl_future_syms = section_objs(info,
> >> "__ksymtab_gpl_future",
> >> sizeof(*mod->gpl_future_syms),
> >> @@ -3381,6 +3443,19 @@ static int post_relocation(struct module *mod, const struct load_info *info)
> >> return module_finalize(info->hdr, info->sechdrs, mod);
> >> }
> >>
> >> +static void verify_namespace_dependencies(struct module *mod)
> >> +{
> >> + struct module_ns_dep *ns_dep;
> >> +
> >> + list_for_each_entry(ns_dep, &mod->ns_dependencies, ns_dep) {
> >> + if (!module_imports_ns(mod, ns_dep->namespace)) {
> >> + pr_warn("%s: module uses symbols from namespace %s,"
> >> + " but does not import it.\n",
> >> + mod->name, ns_dep->namespace);
> >> + }
> >> + }
> >> +}
> >> +
> >> /* Is this module of this name done loading? No locks held. */
> >> static bool finished_loading(const char *name)
> >> {
> >> @@ -3682,6 +3757,8 @@ static int load_module(struct load_info *info, const char __user *uargs,
> >> if (err)
> >> goto free_module;
> >>
> >> + INIT_LIST_HEAD(&mod->ns_dependencies);
> >> +
> >> #ifdef CONFIG_MODULE_SIG
> >> mod->sig_ok = info->sig_ok;
> >> if (!mod->sig_ok) {
> >> @@ -3730,6 +3807,8 @@ static int load_module(struct load_info *info, const char __user *uargs,
> >> if (err < 0)
> >> goto free_modinfo;
> >>
> >> + verify_namespace_dependencies(mod);
> >> +
> >> flush_module_icache(mod);
> >>
> >> /* Now copy in args */
> >> --
> >> 2.18.0.203.gfac676dfb9-goog
> >>
--
Lucas De Marchi
On Wed, Jul 25, 2018 at 6:48 PM, Lucas De Marchi
<[email protected]> wrote:
> this might be because you are looking to the wrong project
> (module-init-tools) rather than kmod that replaced it some years ago?
Oh yes indeed, thanks for pointing that out :-)
>> Just scanning the depmod source code, it seems really trivial to just
>> have depmod accommodate the new symbol name format. Adding Lucas (kmod
>> maintainer) to CC.
>
> Yep, that would be easy and allow depmod to be backward compatible
> since we would do nothing if the symbol doesn't have the suffix.
> As for dependency on a new version, this seems trivial enough to be
> backported to previous releases used on distros so even if they are
> not rolling they would get a compatible depmod.
Thanks for the suggestion. I had also considered modifying the script
that generates System.map to strip out the namespace; but that seems a
bit hacky since it will then mismatch with the actual symbol table
that's in the kernel image. The situation with depmod has gotten me a
bit worried that perhaps there are more tools that look at System.map
or the kernel's symbol table that won't be able to understand the new
format. But of course those could be updated, too.
Another alternative I was considering is leaving the namespace out of
the __ksymtab symbols, and instead for the symbols that have a
namespace, have an entry in __ksymtab (without namespace) and an entry
in a new section __ksymtab_ns (with namespace). We can then discard
__ksymtab_ns when building the final executable/modules, since that
information is not needed at runtime (it's encoded in struct
kernel_symbol). What makes this a bit more complex is that modpost
takes the fully linked version of vmlinux which would already have
__ksymtab_ns stripped, so we'd need to use objcopy to copy out that
section so modpost can use it to read vmlinux's namespaced symbols.
Modules wouldn't have that problem, since modpost processes modules
before their final linking step.
This last approach is more complex than just modifying depmod, but it
does have the benefit that we won't be break userspace tools depending
on the kernel __ksymtab section symbols. On the other hand, perhaps
userspace tools would like to have the namespace information at some
point.
For now I'll keep things as is and write up a patch for depmod, but if
others prefer the __ksymtab_ns approach I described above I don't mind
making that work.
Thanks,
Martijn
>
> CC'ing [email protected] to keep track of this there
>
>
> thanks
> Lucas De Marchi
>
>>
>> Thanks,
>>
>> Jessica
>>
>> >
>> >>
>> >> On x86_64 I saw no difference in binary size (compression), but at
>> >> runtime this will require a word of memory per export to hold the
>> >> namespace. An alternative could be to store namespaced symbols in their
>> >> own section and use a separate 'struct namespaced_kernel_symbol' for
>> >> that section, at the cost of making the module loader more complex.
>> >>
>> >> Signed-off-by: Martijn Coenen <[email protected]>
>> >> ---
>> >> include/asm-generic/export.h | 2 +-
>> >> include/linux/export.h | 83 +++++++++++++++++++++++++++---------
>> >> include/linux/module.h | 13 ++++++
>> >> kernel/module.c | 79 ++++++++++++++++++++++++++++++++++
>> >> 4 files changed, 156 insertions(+), 21 deletions(-)
>> >>
>> >> diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h
>> >> index 68efb950a918..4c3d1afb702f 100644
>> >> --- a/include/asm-generic/export.h
>> >> +++ b/include/asm-generic/export.h
>> >> @@ -29,7 +29,7 @@
>> >> .section ___ksymtab\sec+\name,"a"
>> >> .balign KSYM_ALIGN
>> >> __ksymtab_\name:
>> >> - __put \val, __kstrtab_\name
>> >> + __put \val, __kstrtab_\name, 0
>> >> .previous
>> >> .section __ksymtab_strings,"a"
>> >> __kstrtab_\name:
>> >> diff --git a/include/linux/export.h b/include/linux/export.h
>> >> index ad6b8e697b27..9f6e70eeb85f 100644
>> >> --- a/include/linux/export.h
>> >> +++ b/include/linux/export.h
>> >> @@ -22,6 +22,11 @@ struct kernel_symbol
>> >> {
>> >> unsigned long value;
>> >> const char *name;
>> >> + const char *namespace;
>> >> +};
>> >> +
>> >> +struct namespace_import {
>> >> + const char *namespace;
>> >> };
>> >>
>> >> #ifdef MODULE
>> >> @@ -54,18 +59,28 @@ extern struct module __this_module;
>> >> #define __CRC_SYMBOL(sym, sec)
>> >> #endif
>> >>
>> >> +#define NS_SEPARATOR "."
>> >> +
>> >> +#define MODULE_IMPORT_NS(ns) \
>> >> + static const struct namespace_import __knsimport_##ns \
>> >> + asm("__knsimport_" #ns) \
>> >> + __attribute__((section("__knsimport"), used)) \
>> >> + = { #ns }
>> >> +
>> >> /* For every exported symbol, place a struct in the __ksymtab section */
>> >> -#define ___EXPORT_SYMBOL(sym, sec) \
>> >> +#define ___EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2) \
>> >> extern typeof(sym) sym; \
>> >> __CRC_SYMBOL(sym, sec) \
>> >> - static const char __kstrtab_##sym[] \
>> >> + static const char __kstrtab_##sym##nspost[] \
>> >> __attribute__((section("__ksymtab_strings"), aligned(1))) \
>> >> = #sym; \
>> >> - static const struct kernel_symbol __ksymtab_##sym \
>> >> + static const struct kernel_symbol __ksymtab_##sym##nspost \
>> >> + asm("__ksymtab_" #sym nspost2) \
>> >> __used \
>> >> - __attribute__((section("___ksymtab" sec "+" #sym), used)) \
>> >> + __attribute__((section("___ksymtab" sec "+" #sym #nspost))) \
>> >> + __attribute__((used)) \
>> >> __attribute__((aligned(sizeof(void *)))) \
>> >> - = { (unsigned long)&sym, __kstrtab_##sym }
>> >> + = { (unsigned long)&sym, __kstrtab_##sym##nspost, ns }
>> >>
>> >> #if defined(__KSYM_DEPS__)
>> >>
>> >> @@ -76,52 +91,80 @@ extern struct module __this_module;
>> >> * system filters out from the preprocessor output (see ksym_dep_filter
>> >> * in scripts/Kbuild.include).
>> >> */
>> >> -#define __EXPORT_SYMBOL(sym, sec) === __KSYM_##sym ===
>> >> +#define __EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2) === __KSYM_##sym ===
>> >>
>> >> #elif defined(CONFIG_TRIM_UNUSED_KSYMS)
>> >>
>> >> #include <generated/autoksyms.h>
>> >>
>> >> -#define __EXPORT_SYMBOL(sym, sec) \
>> >> - __cond_export_sym(sym, sec, __is_defined(__KSYM_##sym))
>> >> -#define __cond_export_sym(sym, sec, conf) \
>> >> - ___cond_export_sym(sym, sec, conf)
>> >> -#define ___cond_export_sym(sym, sec, enabled) \
>> >> - __cond_export_sym_##enabled(sym, sec)
>> >> -#define __cond_export_sym_1(sym, sec) ___EXPORT_SYMBOL(sym, sec)
>> >> -#define __cond_export_sym_0(sym, sec) /* nothing */
>> >> +#define __EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2) \
>> >> + __cond_export_sym(sym, sec, ns, nspost, nspost2, \
>> >> + __is_defined(__KSYM_##sym))
>> >> +#define __cond_export_sym(sym, sec, ns, nspost, nspost2, conf) \
>> >> + ___cond_export_sym(sym, sec, ns, nspost, nspost2, conf)
>> >> +#define ___cond_export_sym(sym, sec, ns, nspost, nspost2, enabled) \
>> >> + __cond_export_sym_##enabled(sym, sec, ns, nspost, nspost2)
>> >> +#define __cond_export_sym_1(sym, sec, ns, nspost, nspost2) \
>> >> + ___EXPORT_SYMBOL(sym, sec, ns, nspost, nspost2)
>> >> +#define __cond_export_sym_0(sym, sec, ns, nspost, nspost2) /* nothing */
>> >>
>> >> #else
>> >> #define __EXPORT_SYMBOL ___EXPORT_SYMBOL
>> >> #endif
>> >>
>> >> #define EXPORT_SYMBOL(sym) \
>> >> - __EXPORT_SYMBOL(sym, "")
>> >> + __EXPORT_SYMBOL(sym, "", NULL, ,)
>> >>
>> >> #define EXPORT_SYMBOL_GPL(sym) \
>> >> - __EXPORT_SYMBOL(sym, "_gpl")
>> >> + __EXPORT_SYMBOL(sym, "_gpl", NULL, ,)
>> >>
>> >> #define EXPORT_SYMBOL_GPL_FUTURE(sym) \
>> >> - __EXPORT_SYMBOL(sym, "_gpl_future")
>> >> + __EXPORT_SYMBOL(sym, "_gpl_future", NULL, ,)
>> >> +
>> >> +#define EXPORT_SYMBOL_NS(sym, ns) \
>> >> + __EXPORT_SYMBOL(sym, "", #ns, __##ns, NS_SEPARATOR #ns)
>> >> +
>> >> +#define EXPORT_SYMBOL_NS_GPL(sym, ns) \
>> >> + __EXPORT_SYMBOL(sym, "_gpl", #ns, __##ns, NS_SEPARATOR #ns)
>> >>
>> >> #ifdef CONFIG_UNUSED_SYMBOLS
>> >> -#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused")
>> >> -#define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl")
>> >> +#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused", , ,)
>> >> +#define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl", , ,)
>> >> #else
>> >> #define EXPORT_UNUSED_SYMBOL(sym)
>> >> #define EXPORT_UNUSED_SYMBOL_GPL(sym)
>> >> #endif
>> >>
>> >> -#endif /* __GENKSYMS__ */
>> >> +#endif /* __KERNEL__ && !__GENKSYMS__ */
>> >> +
>> >> +#if defined(__GENKSYMS__)
>> >> +/*
>> >> + * When we're running genksyms, ignore the namespace and make the _NS
>> >> + * variants look like the normal ones. There are two reasons for this:
>> >> + * 1) In the normal definition of EXPORT_SYMBOL_NS, the 'ns' macro
>> >> + * argument is itself not expanded because it's always tokenized or
>> >> + * concatenated; but when running genksyms, a blank definition of the
>> >> + * macro does allow the argument to be expanded; if a namespace
>> >> + * happens to collide with a #define, this can cause issues.
>> >> + * 2) There's no need to modify genksyms to deal with the _NS variants
>> >> + */
>> >> +#define EXPORT_SYMBOL_NS(sym, ns) \
>> >> + EXPORT_SYMBOL(sym)
>> >> +#define EXPORT_SYMBOL_NS_GPL(sym, ns) \
>> >> + EXPORT_SYMBOL_GPL(sym)
>> >> +#endif
>> >>
>> >> #else /* !CONFIG_MODULES... */
>> >>
>> >> #define EXPORT_SYMBOL(sym)
>> >> +#define EXPORT_SYMBOL_NS(sym, ns)
>> >> +#define EXPORT_SYMBOL_NS_GPL(sym, ns)
>> >> #define EXPORT_SYMBOL_GPL(sym)
>> >> #define EXPORT_SYMBOL_GPL_FUTURE(sym)
>> >> #define EXPORT_UNUSED_SYMBOL(sym)
>> >> #define EXPORT_UNUSED_SYMBOL_GPL(sym)
>> >>
>> >> +#define MODULE_IMPORT_NS(ns)
>> >> #endif /* CONFIG_MODULES */
>> >> #endif /* !__ASSEMBLY__ */
>> >>
>> >> diff --git a/include/linux/module.h b/include/linux/module.h
>> >> index d44df9b2c131..afab4e8fa188 100644
>> >> --- a/include/linux/module.h
>> >> +++ b/include/linux/module.h
>> >> @@ -268,6 +268,12 @@ void *__symbol_get(const char *symbol);
>> >> void *__symbol_get_gpl(const char *symbol);
>> >> #define symbol_get(x) ((typeof(&x))(__symbol_get(VMLINUX_SYMBOL_STR(x))))
>> >>
>> >> +/* namespace dependencies of the module */
>> >> +struct module_ns_dep {
>> >> + struct list_head ns_dep;
>> >> + const char *namespace;
>> >> +};
>> >> +
>> >> /* modules using other modules: kdb wants to see this. */
>> >> struct module_use {
>> >> struct list_head source_list;
>> >> @@ -359,6 +365,13 @@ struct module {
>> >> const struct kernel_symbol *gpl_syms;
>> >> const s32 *gpl_crcs;
>> >>
>> >> + /* Namespace imports */
>> >> + unsigned int num_ns_imports;
>> >> + const struct namespace_import *ns_imports;
>> >> +
>> >> + /* Namespace dependencies */
>> >> + struct list_head ns_dependencies;
>> >> +
>> >> #ifdef CONFIG_UNUSED_SYMBOLS
>> >> /* unused exported symbols. */
>> >> const struct kernel_symbol *unused_syms;
>> >> diff --git a/kernel/module.c b/kernel/module.c
>> >> index f475f30eed8c..63de0fe849f9 100644
>> >> --- a/kernel/module.c
>> >> +++ b/kernel/module.c
>> >> @@ -1166,6 +1166,51 @@ static inline int module_unload_init(struct module *mod)
>> >> }
>> >> #endif /* CONFIG_MODULE_UNLOAD */
>> >>
>> >> +static bool module_has_ns_dependency(struct module *mod, const char *ns)
>> >> +{
>> >> + struct module_ns_dep *ns_dep;
>> >> +
>> >> + list_for_each_entry(ns_dep, &mod->ns_dependencies, ns_dep) {
>> >> + if (strcmp(ns_dep->namespace, ns) == 0)
>> >> + return true;
>> >> + }
>> >> +
>> >> + return false;
>> >> +}
>> >> +
>> >> +static int add_module_ns_dependency(struct module *mod, const char *ns)
>> >> +{
>> >> + struct module_ns_dep *ns_dep;
>> >> +
>> >> + if (module_has_ns_dependency(mod, ns))
>> >> + return 0;
>> >> +
>> >> + ns_dep = kmalloc(sizeof(*ns_dep), GFP_ATOMIC);
>> >> + if (!ns_dep)
>> >> + return -ENOMEM;
>> >> +
>> >> + ns_dep->namespace = ns;
>> >> +
>> >> + list_add(&ns_dep->ns_dep, &mod->ns_dependencies);
>> >> +
>> >> + return 0;
>> >> +}
>> >> +
>> >> +static bool module_imports_ns(struct module *mod, const char *ns)
>> >> +{
>> >> + size_t i;
>> >> +
>> >> + if (!ns)
>> >> + return true;
>> >> +
>> >> + for (i = 0; i < mod->num_ns_imports; ++i) {
>> >> + if (!strcmp(mod->ns_imports[i].namespace, ns))
>> >> + return true;
>> >> + }
>> >> +
>> >> + return false;
>> >> +}
>> >> +
>> >> static size_t module_flags_taint(struct module *mod, char *buf)
>> >> {
>> >> size_t l = 0;
>> >> @@ -1415,6 +1460,18 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
>> >> goto getname;
>> >> }
>> >>
>> >> + /*
>> >> + * We can't yet verify that the module actually imports this
>> >> + * namespace, because the imports themselves are only available
>> >> + * after processing the symbol table and doing relocation; so
>> >> + * instead just record the dependency and check later.
>> >> + */
>> >> + if (sym->namespace) {
>> >> + err = add_module_ns_dependency(mod, sym->namespace);
>> >> + if (err)
>> >> + sym = ERR_PTR(err);
>> >> + }
>> >> +
>> >> getname:
>> >> /* We must make copy under the lock if we failed to get ref. */
>> >> strncpy(ownername, module_name(owner), MODULE_NAME_LEN);
>> >> @@ -3061,6 +3118,11 @@ static int find_module_sections(struct module *mod, struct load_info *info)
>> >> sizeof(*mod->gpl_syms),
>> >> &mod->num_gpl_syms);
>> >> mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
>> >> +
>> >> + mod->ns_imports = section_objs(info, "__knsimport",
>> >> + sizeof(*mod->ns_imports),
>> >> + &mod->num_ns_imports);
>> >> +
>> >> mod->gpl_future_syms = section_objs(info,
>> >> "__ksymtab_gpl_future",
>> >> sizeof(*mod->gpl_future_syms),
>> >> @@ -3381,6 +3443,19 @@ static int post_relocation(struct module *mod, const struct load_info *info)
>> >> return module_finalize(info->hdr, info->sechdrs, mod);
>> >> }
>> >>
>> >> +static void verify_namespace_dependencies(struct module *mod)
>> >> +{
>> >> + struct module_ns_dep *ns_dep;
>> >> +
>> >> + list_for_each_entry(ns_dep, &mod->ns_dependencies, ns_dep) {
>> >> + if (!module_imports_ns(mod, ns_dep->namespace)) {
>> >> + pr_warn("%s: module uses symbols from namespace %s,"
>> >> + " but does not import it.\n",
>> >> + mod->name, ns_dep->namespace);
>> >> + }
>> >> + }
>> >> +}
>> >> +
>> >> /* Is this module of this name done loading? No locks held. */
>> >> static bool finished_loading(const char *name)
>> >> {
>> >> @@ -3682,6 +3757,8 @@ static int load_module(struct load_info *info, const char __user *uargs,
>> >> if (err)
>> >> goto free_module;
>> >>
>> >> + INIT_LIST_HEAD(&mod->ns_dependencies);
>> >> +
>> >> #ifdef CONFIG_MODULE_SIG
>> >> mod->sig_ok = info->sig_ok;
>> >> if (!mod->sig_ok) {
>> >> @@ -3730,6 +3807,8 @@ static int load_module(struct load_info *info, const char __user *uargs,
>> >> if (err < 0)
>> >> goto free_modinfo;
>> >>
>> >> + verify_namespace_dependencies(mod);
>> >> +
>> >> flush_module_icache(mod);
>> >>
>> >> /* Now copy in args */
>> >> --
>> >> 2.18.0.203.gfac676dfb9-goog
>> >>
>
>
>
> --
> Lucas De Marchi
As of Linux 5.3-rc4, there are 31203 [1] exported symbols in the kernel.
That is a growth of almost 1000 symbols since 4.17 (30206 [2]). There
seems to be some consensus amongst kernel devs that the export surface
is too large, and hard to reason about.
Generally, these symbols fall in one of these categories:
1) Symbols actually meant for drivers
2) Symbols that are only exported because functionality is split over
multiple modules, yet they really shouldn't be used by modules outside
of their own subsystem
3) Symbols really only meant for in-tree use
When module developers try to upstream their code, it regularly turns
out that they are using exported symbols that they really shouldn't be
using. This problem is even bigger for drivers that are currently
out-of-tree, which may be using many symbols that they shouldn't be
using, and that break when those symbols are removed or modified.
This patch allows subsystem maintainers to partition their exported
symbols into separate namespaces, and module authors to import such
namespaces only when needed.
This allows subsystem maintainers to more easily limit availability of
these namespaced symbols to other parts of the kernel. It can also be
used to partition the set of exported symbols for documentation
purposes; for example, a set of symbols that is really only used for
debugging could be in a "SUBSYSTEM_DEBUG" namespace.
I continued the work mainly done by Martijn Coenen. In this v2 the
following changes have been introduced compared to v1 of this series:
- Rather than adding and evaluating separate sections __knsimport_NS,
use modinfo tags to declare the namespaces a module introduces.
Adjust modpost and the module loader accordingly.
- Also add support for reading multiple modinfo values for the same tag
to allow list-like access to modinfo tags.
- The macros in export.h have been cleaned up to avoid redundancy in the
macro parameters (ns, nspost, nspost2).
- The introduction of relative references in the ksymtab entries caused
a rework of the macros to accommodate that configuration as well.
- Alignment of kernel_symbol in the ksymtab needed to be fixed to allow
growing the kernel_symbol struct.
- Modpost does now also append the namespace suffix to the symbol
entries in Module.symvers.
- The configuration option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS allows
relaxing the enforcement of properly declared namespace imports at module
loading time.
- Symbols can be collectively exported into a namespace by defining
DEFAULT_SYMBOL_NAMESPACE in the corresponding Makefile.
- The requirement for a very recent coccinelle spatch has been lifted by
simplifying the script.
- nsdeps does now ensures MODULE_IMPORT_NS statements are sorted when
patching the module source files.
- Some minor bugs have been addressed in nsdeps to allow it to work with
modules that have more than one source file.
- The RFC for the usb-storage symbols has been simplified by using
DEFAULT_SYMBOL_NAMESPACE=USB_STORAGE rather than explicitly exporting each
and every symbol into that new namespace.
This patch series was developed against v5.3-rc4.
[1] git grep "^EXPORT_SYMBOL\w*(" v5.3-rc4 | wc -l
[2] git grep "^EXPORT_SYMBOL\w*(" v4.17 | wc -l
Matthias Maennich (10):
module: support reading multiple values per modinfo tag
export: explicitly align struct kernel_symbol
module: add support for symbol namespaces.
modpost: add support for symbol namespaces
module: add config option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
export: allow definition default namespaces in Makefiles or sources
modpost: add support for generating namespace dependencies
scripts: Coccinelle script for namespace dependencies.
usb-storage: remove single-use define for debugging
RFC: usb-storage: export symbols in USB_STORAGE namespace
MAINTAINERS | 5 +
Makefile | 12 ++
arch/m68k/include/asm/export.h | 1 -
drivers/usb/storage/Makefile | 2 +
drivers/usb/storage/alauda.c | 1 +
drivers/usb/storage/cypress_atacb.c | 1 +
drivers/usb/storage/datafab.c | 1 +
drivers/usb/storage/debug.h | 2 -
drivers/usb/storage/ene_ub6250.c | 1 +
drivers/usb/storage/freecom.c | 1 +
drivers/usb/storage/isd200.c | 1 +
drivers/usb/storage/jumpshot.c | 1 +
drivers/usb/storage/karma.c | 1 +
drivers/usb/storage/onetouch.c | 1 +
drivers/usb/storage/realtek_cr.c | 1 +
drivers/usb/storage/scsiglue.c | 2 +-
drivers/usb/storage/sddr09.c | 1 +
drivers/usb/storage/sddr55.c | 1 +
drivers/usb/storage/shuttle_usbat.c | 1 +
drivers/usb/storage/uas.c | 1 +
include/asm-generic/export.h | 14 +-
include/linux/export.h | 92 +++++++++++--
include/linux/module.h | 2 +
init/Kconfig | 14 ++
kernel/module.c | 67 ++++++++-
scripts/Makefile.modpost | 4 +-
scripts/coccinelle/misc/add_namespace.cocci | 23 ++++
scripts/mod/modpost.c | 144 ++++++++++++++++++--
scripts/mod/modpost.h | 9 ++
scripts/nsdeps | 54 ++++++++
30 files changed, 421 insertions(+), 40 deletions(-)
create mode 100644 scripts/coccinelle/misc/add_namespace.cocci
create mode 100644 scripts/nsdeps
--
2.23.0.rc1.153.gdeed80330f-goog
Similar to modpost's get_next_modinfo(), introduce get_next_modinfo() in
kernel/module.c to acquire any further values associated with the same
modinfo tag name. That is useful for any tags that have multiple
occurrences (such as 'alias'), but is in particular introduced here as
part of the symbol namespaces patch series to read the (potentially)
multiple namespaces a module is importing.
Reviewed-by: Joel Fernandes (Google) <[email protected]>
Reviewed-by: Martijn Coenen <[email protected]>
Signed-off-by: Matthias Maennich <[email protected]>
---
kernel/module.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/kernel/module.c b/kernel/module.c
index 5933395af9a0..a23067907169 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2481,7 +2481,8 @@ static char *next_string(char *string, unsigned long *secsize)
return string;
}
-static char *get_modinfo(struct load_info *info, const char *tag)
+static char *get_next_modinfo(const struct load_info *info, const char *tag,
+ char *prev)
{
char *p;
unsigned int taglen = strlen(tag);
@@ -2492,13 +2493,25 @@ static char *get_modinfo(struct load_info *info, const char *tag)
* get_modinfo() calls made before rewrite_section_headers()
* must use sh_offset, as sh_addr isn't set!
*/
- for (p = (char *)info->hdr + infosec->sh_offset; p; p = next_string(p, &size)) {
+ char *modinfo = (char *)info->hdr + infosec->sh_offset;
+
+ if (prev) {
+ size -= prev - modinfo;
+ modinfo = next_string(prev, &size);
+ }
+
+ for (p = modinfo; p; p = next_string(p, &size)) {
if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
return p + taglen + 1;
}
return NULL;
}
+static char *get_modinfo(const struct load_info *info, const char *tag)
+{
+ return get_next_modinfo(info, tag, NULL);
+}
+
static void setup_modinfo(struct module *mod, struct load_info *info)
{
struct module_attribute *attr;
--
2.23.0.rc1.153.gdeed80330f-goog
A script that uses the '<module>.ns_deps' file generated by modpost to
automatically add the required symbol namespace dependencies to each
module.
Usage:
1) Move some symbols to a namespace with EXPORT_SYMBOL_NS() or define
DEFAULT_SYMBOL_NAMESPACE
2) Run 'make' (or 'make modules') and get warnings about modules not
importing that namespace.
3) Run 'make nsdeps' to automatically add required import statements
to said modules.
This makes it easer for subsystem maintainers to introduce and maintain
symbol namespaces into their codebase.
Co-developed-by: Martijn Coenen <[email protected]>
Signed-off-by: Martijn Coenen <[email protected]>
Signed-off-by: Matthias Maennich <[email protected]>
---
MAINTAINERS | 5 ++
Makefile | 12 +++++
scripts/Makefile.modpost | 4 +-
scripts/coccinelle/misc/add_namespace.cocci | 23 +++++++++
scripts/nsdeps | 54 +++++++++++++++++++++
5 files changed, 97 insertions(+), 1 deletion(-)
create mode 100644 scripts/coccinelle/misc/add_namespace.cocci
create mode 100644 scripts/nsdeps
diff --git a/MAINTAINERS b/MAINTAINERS
index e81e60bd7c26..aa169070a052 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11414,6 +11414,11 @@ S: Maintained
T: git git://git.kernel.org/pub/scm/linux/kernel/git/wtarreau/nolibc.git
F: tools/include/nolibc/
+NSDEPS
+M: Matthias Maennich <[email protected]>
+S: Maintained
+F: scripts/nsdeps
+
NTB AMD DRIVER
M: Shyam Sundar S K <[email protected]>
L: [email protected]
diff --git a/Makefile b/Makefile
index 1b23f95db176..c5c3356e133c 100644
--- a/Makefile
+++ b/Makefile
@@ -1500,6 +1500,9 @@ help:
@echo ' headerdep - Detect inclusion cycles in headers'
@echo ' coccicheck - Check with Coccinelle'
@echo ''
+ @echo 'Tools:'
+ @echo ' nsdeps - Generate missing symbol namespace dependencies'
+ @echo ''
@echo 'Kernel selftest:'
@echo ' kselftest - Build and run kernel selftest (run as root)'
@echo ' Build, install, and boot kernel before'
@@ -1687,6 +1690,15 @@ quiet_cmd_tags = GEN $@
tags TAGS cscope gtags: FORCE
$(call cmd,tags)
+# Script to generate missing namespace dependencies
+# ---------------------------------------------------------------------------
+
+PHONY += nsdeps
+
+nsdeps:
+ $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost nsdeps
+ $(Q)$(CONFIG_SHELL) $(srctree)/scripts/$@
+
# Scripts to check various things for consistency
# ---------------------------------------------------------------------------
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index 26e6574ecd08..743fe3a2e885 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -56,7 +56,8 @@ MODPOST = scripts/mod/modpost \
$(if $(KBUILD_EXTMOD),$(addprefix -e ,$(KBUILD_EXTRA_SYMBOLS))) \
$(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \
$(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \
- $(if $(KBUILD_MODPOST_WARN),-w)
+ $(if $(KBUILD_MODPOST_WARN),-w) \
+ $(if $(filter nsdeps,$(MAKECMDGOALS)),-d)
ifdef MODPOST_VMLINUX
@@ -134,6 +135,7 @@ $(modules): %.ko :%.o %.mod.o FORCE
targets += $(modules)
+nsdeps: __modpost
# Add FORCE to the prequisites of a target to force it to be always rebuilt.
# ---------------------------------------------------------------------------
diff --git a/scripts/coccinelle/misc/add_namespace.cocci b/scripts/coccinelle/misc/add_namespace.cocci
new file mode 100644
index 000000000000..c832bb6445a8
--- /dev/null
+++ b/scripts/coccinelle/misc/add_namespace.cocci
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+/// Adds missing MODULE_IMPORT_NS statements to source files
+///
+/// This script is usually called from scripts/nsdeps with -D ns=<namespace> to
+/// add a missing namespace tag to a module source file.
+///
+
+@has_ns_import@
+declarer name MODULE_IMPORT_NS;
+identifier virtual.ns;
+@@
+MODULE_IMPORT_NS(ns);
+
+// Add missing imports, but only adjacent to a MODULE_LICENSE statement.
+// That ensures we are adding it only to the main module source file.
+@do_import depends on !has_ns_import@
+declarer name MODULE_LICENSE;
+expression license;
+identifier virtual.ns;
+@@
+MODULE_LICENSE(license);
++ MODULE_IMPORT_NS(ns);
diff --git a/scripts/nsdeps b/scripts/nsdeps
new file mode 100644
index 000000000000..148db65a830f
--- /dev/null
+++ b/scripts/nsdeps
@@ -0,0 +1,54 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Linux kernel symbol namespace import generator
+#
+# This script requires at least spatch
+# version 1.0.4.
+SPATCH_REQ_VERSION="1.0.4"
+
+DIR="$(dirname $(readlink -f $0))/.."
+SPATCH="`which ${SPATCH:=spatch}`"
+if [ ! -x "$SPATCH" ]; then
+ echo 'spatch is part of the Coccinelle project and is available at http://coccinelle.lip6.fr/'
+ exit 1
+fi
+
+SPATCH_REQ_VERSION_NUM=$(echo $SPATCH_REQ_VERSION | ${DIR}/scripts/ld-version.sh)
+SPATCH_VERSION=$($SPATCH --version | head -1 | awk '{print $3}')
+SPATCH_VERSION_NUM=$(echo $SPATCH_VERSION | ${DIR}/scripts/ld-version.sh)
+
+if [ "$SPATCH_VERSION_NUM" -lt "$SPATCH_REQ_VERSION_NUM" ] ; then
+ echo 'spatch needs to be version 1.06 or higher'
+ exit 1
+fi
+
+generate_deps_for_ns() {
+ $SPATCH --very-quiet --in-place --sp-file \
+ $srctree/scripts/coccinelle/misc/add_namespace.cocci -D ns=$1 $2
+}
+
+generate_deps() {
+ local mod_file=`echo $@ | sed -e 's/\.ns_deps/\.mod/'`
+ local mod_name=`cat $mod_file | sed -n 1p | sed -e 's/\/[^.]*$//'`
+ local mod_source_files=`cat $mod_file | sed -n 2p | sed -e 's/\.o/\.c/g'`
+ for ns in `cat $@`; do
+ echo "Adding namespace $ns to module $mod_name (if needed)."
+ generate_deps_for_ns $ns $mod_source_files
+ # sort the imports
+ for source_file in $mod_source_files; do
+ sed '/MODULE_IMPORT_NS/Q' $source_file > ${source_file}.tmp
+ offset=$(wc -l ${source_file}.tmp | awk '{print $1;}')
+ cat $source_file | grep MODULE_IMPORT_NS | sort -u >> ${source_file}.tmp
+ tail -n +$((offset +1)) ${source_file} | grep -v MODULE_IMPORT_NS >> ${source_file}.tmp
+ if ! diff -q ${source_file} ${source_file}.tmp; then
+ mv ${source_file}.tmp ${source_file}
+ else
+ rm ${source_file}.tmp
+ fi
+ done
+ done
+}
+
+for f in `find $srctree/.tmp_versions/ -name *.ns_deps`; do
+ generate_deps $f
+done
--
2.23.0.rc1.153.gdeed80330f-goog
On Tue, Aug 13, 2019 at 01:16:58PM +0100, Matthias Maennich wrote:
> Similar to modpost's get_next_modinfo(), introduce get_next_modinfo() in
> kernel/module.c to acquire any further values associated with the same
> modinfo tag name. That is useful for any tags that have multiple
> occurrences (such as 'alias'), but is in particular introduced here as
> part of the symbol namespaces patch series to read the (potentially)
> multiple namespaces a module is importing.
>
> Reviewed-by: Joel Fernandes (Google) <[email protected]>
> Reviewed-by: Martijn Coenen <[email protected]>
> Signed-off-by: Matthias Maennich <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
On Tue, Aug 13, 2019 at 01:17:05PM +0100, Matthias Maennich wrote:
> A script that uses the '<module>.ns_deps' file generated by modpost to
> automatically add the required symbol namespace dependencies to each
> module.
>
> Usage:
> 1) Move some symbols to a namespace with EXPORT_SYMBOL_NS() or define
> DEFAULT_SYMBOL_NAMESPACE
> 2) Run 'make' (or 'make modules') and get warnings about modules not
> importing that namespace.
> 3) Run 'make nsdeps' to automatically add required import statements
> to said modules.
>
> This makes it easer for subsystem maintainers to introduce and maintain
> symbol namespaces into their codebase.
>
> Co-developed-by: Martijn Coenen <[email protected]>
> Signed-off-by: Martijn Coenen <[email protected]>
> Signed-off-by: Matthias Maennich <[email protected]>
> ---
I really can't express just how cool this patch is. I was amazed when I
first saw it in action a long time ago, and still am.
Reviewed-by: Greg Kroah-Hartman <[email protected]>
On Tue, Aug 13, 2019 at 01:17:05PM +0100, Matthias Maennich wrote:
> A script that uses the '<module>.ns_deps' file generated by modpost to
> automatically add the required symbol namespace dependencies to each
> module.
>
> Usage:
> 1) Move some symbols to a namespace with EXPORT_SYMBOL_NS() or define
> DEFAULT_SYMBOL_NAMESPACE
> 2) Run 'make' (or 'make modules') and get warnings about modules not
> importing that namespace.
> 3) Run 'make nsdeps' to automatically add required import statements
> to said modules.
>
> This makes it easer for subsystem maintainers to introduce and maintain
> symbol namespaces into their codebase.
>
> Co-developed-by: Martijn Coenen <[email protected]>
> Signed-off-by: Martijn Coenen <[email protected]>
> Signed-off-by: Matthias Maennich <[email protected]>
> ---
[]
> MAINTAINERS | 5 ++
> Makefile | 12 +++++
> scripts/Makefile.modpost | 4 +-
> scripts/coccinelle/misc/add_namespace.cocci | 23 +++++++++
> scripts/nsdeps | 54 +++++++++++++++++++++
> 5 files changed, 97 insertions(+), 1 deletion(-)
> create mode 100644 scripts/coccinelle/misc/add_namespace.cocci
> create mode 100644 scripts/nsdeps
[]
> +if [ "$SPATCH_VERSION_NUM" -lt "$SPATCH_REQ_VERSION_NUM" ] ; then
> + echo 'spatch needs to be version 1.06 or higher'
Nitpick: 1.0.6
> + exit 1
> +fi
--
Himanshu Jha
Undergraduate Student
Department of Electronics & Communication
Guru Tegh Bahadur Institute of Technology
On Wed, Aug 14, 2019 at 12:06:11PM +0530, Himanshu Jha wrote:
>On Tue, Aug 13, 2019 at 01:17:05PM +0100, Matthias Maennich wrote:
>> A script that uses the '<module>.ns_deps' file generated by modpost to
>> automatically add the required symbol namespace dependencies to each
>> module.
>>
>> Usage:
>> 1) Move some symbols to a namespace with EXPORT_SYMBOL_NS() or define
>> DEFAULT_SYMBOL_NAMESPACE
>> 2) Run 'make' (or 'make modules') and get warnings about modules not
>> importing that namespace.
>> 3) Run 'make nsdeps' to automatically add required import statements
>> to said modules.
>>
>> This makes it easer for subsystem maintainers to introduce and maintain
>> symbol namespaces into their codebase.
>>
>> Co-developed-by: Martijn Coenen <[email protected]>
>> Signed-off-by: Martijn Coenen <[email protected]>
>> Signed-off-by: Matthias Maennich <[email protected]>
>> ---
>
>[]
>
>> MAINTAINERS | 5 ++
>> Makefile | 12 +++++
>> scripts/Makefile.modpost | 4 +-
>> scripts/coccinelle/misc/add_namespace.cocci | 23 +++++++++
>> scripts/nsdeps | 54 +++++++++++++++++++++
>> 5 files changed, 97 insertions(+), 1 deletion(-)
>> create mode 100644 scripts/coccinelle/misc/add_namespace.cocci
>> create mode 100644 scripts/nsdeps
>
>[]
>
>> +if [ "$SPATCH_VERSION_NUM" -lt "$SPATCH_REQ_VERSION_NUM" ] ; then
>> + echo 'spatch needs to be version 1.06 or higher'
>
>Nitpick: 1.0.6
>
Good catch! Thanks!
Actually it needs to be even 1.0.4, so I will just use
$SPATCH_REQ_VERSION from above.
>> + exit 1
>> +fi
>
>
>--
>Himanshu Jha
>Undergraduate Student
>Department of Electronics & Communication
>Guru Tegh Bahadur Institute of Technology
> +generate_deps_for_ns() {
> + $SPATCH --very-quiet --in-place --sp-file \
> + $srctree/scripts/coccinelle/misc/add_namespace.cocci -D ns=$1 $2
> +}
* Where will the variable “srctree” be set for the file “scripts/nsdeps”?
* Would you like to support a separate build directory for desired adjustments?
* How do you think about to check error handling around such commands?
> +generate_deps() {
…
> + for source_file in $mod_source_files; do
> + sed '/MODULE_IMPORT_NS/Q' $source_file > ${source_file}.tmp
…
I suggest to assign the name for the temporary file to a variable
which should be used by subsequent commands.
Regards,
Markus
On Thu, Aug 15, 2019 at 03:50:38PM +0200, Markus Elfring wrote:
>> +generate_deps_for_ns() {
>> + $SPATCH --very-quiet --in-place --sp-file \
>> + $srctree/scripts/coccinelle/misc/add_namespace.cocci -D ns=$1 $2
>> +}
>
>* Where will the variable “srctree” be set for the file “scripts/nsdeps”?
>
$srctree is defined by kbuild in the toplevel Makefile.
>* Would you like to support a separate build directory for desired adjustments?
>
No, as the purpose of this script is to directly patch the kernel
sources where applicable.
>* How do you think about to check error handling around such commands?
>
>
spatch emits a descriptive message on error. I will add a 'set
-e' to the script so that it aborts on errors.
>> +generate_deps() {
>…
>> + for source_file in $mod_source_files; do
>> + sed '/MODULE_IMPORT_NS/Q' $source_file > ${source_file}.tmp
>…
>
>I suggest to assign the name for the temporary file to a variable
>which should be used by subsequent commands.
I somehow don't agree that this is an improvement to the code as the
variable would likely be something like ${source_file_tmp}. Sticking to
${source_file}.tmp does express the intent of a temporary file next to
the original source file and the reader of the code does not need to
reason about the value of ${source_file_tmp}.
Cheers,
Matthias
> $srctree is defined by kbuild in the toplevel Makefile.
How is this variable passed to the file “scripts/nsdeps”?
>> * Would you like to support a separate build directory for desired adjustments?
>
> No, as the purpose of this script is to directly patch the kernel
> sources where applicable.
Will there occasionally be a need to provide a generated patch
(without in-place file modification)?
>> I suggest to assign the name for the temporary file to a variable
>> which should be used by subsequent commands.
>
> I somehow don't agree that this is an improvement to the code as the
> variable would likely be something like ${source_file_tmp}.
Would you dare to choose a shorter variable name?
> ${source_file}.tmp does express the intent of a temporary file next to
> the original source file and the reader of the code does not need to
> reason about the value of ${source_file_tmp}.
I would find a code variant with less suffix repetition nicer.
Regards,
Markus
As of Linux 5.3-rc7, there are 31207 [1] exported symbols in the kernel.
That is a growth of roughly 1000 symbols since 4.17 (30206 [2]). There
seems to be some consensus amongst kernel devs that the export surface
is too large, and hard to reason about.
Generally, these symbols fall in one of these categories:
1) Symbols actually meant for drivers
2) Symbols that are only exported because functionality is split over
multiple modules, yet they really shouldn't be used by modules outside
of their own subsystem
3) Symbols really only meant for in-tree use
When module developers try to upstream their code, it regularly turns
out that they are using exported symbols that they really shouldn't be
using. This problem is even bigger for drivers that are currently
out-of-tree, which may be using many symbols that they shouldn't be
using, and that break when those symbols are removed or modified.
This patch allows subsystem maintainers to partition their exported
symbols into separate namespaces, and module authors to import such
namespaces only when needed.
This allows subsystem maintainers to more easily limit availability of
these namespaced symbols to other parts of the kernel. It can also be
used to partition the set of exported symbols for documentation
purposes; for example, a set of symbols that is really only used for
debugging could be in a "SUBSYSTEM_DEBUG" namespace.
The series contains two RFC patches that do not need to be merged along
with the rest of the series, but they serve as a reference for using the
symbol namespaces. Especially, the watchdog subsystem might not be
affected by the issues addressed by Symbol Namespaces. I left the patch
in for reference anyway for demonstration purposes.
I continued the work mainly done by Martijn Coenen.
Changes in v2:
- Rather than adding and evaluating separate sections __knsimport_NS,
use modinfo tags to declare the namespaces a module introduces.
Adjust modpost and the module loader accordingly.
- Also add support for reading multiple modinfo values for the same tag
to allow list-like access to modinfo tags.
- The macros in export.h have been cleaned up to avoid redundancy in the
macro parameters (ns, nspost, nspost2).
- The introduction of relative references in the ksymtab entries caused
a rework of the macros to accommodate that configuration as well.
- Alignment of kernel_symbol in the ksymtab needed to be fixed to allow
growing the kernel_symbol struct.
- Modpost does now also append the namespace suffix to the symbol
entries in Module.symvers.
- The configuration option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS allows
relaxing the enforcement of properly declared namespace imports at
module loading time.
- Symbols can be collectively exported into a namespace by defining
DEFAULT_SYMBOL_NAMESPACE in the corresponding Makefile.
- The requirement for a very recent coccinelle spatch has been lifted by
simplifying the script.
- nsdeps does now ensures MODULE_IMPORT_NS statements are sorted when
patching the module source files.
- Some minor bugs have been addressed in nsdeps to allow it to work with
modules that have more than one source file.
- The RFC for the usb-storage symbols has been simplified by using
DEFAULT_SYMBOL_NAMESPACE=USB_STORAGE rather than explicitly exporting
each and every symbol into that new namespace.
Changes in v3:
- Reword the documentation for the
MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS option for clarification.
- Fix printed required version of spatch in coccinelle script.
- Adopt kbuild changes for modpost: .mod files are no longer generated
in .tmp_versions. Similarely, generate the .ns_deps files in the tree
along with the .mod files. Also, nsdeps now uses modules.order as
source for the list modules to consider.
- Add an RFC patch to introduce the namespace WATCHDOG_CORE for symbols
exported in watchdog_core.c.
Changes in v4:
- scripts/nsdeps:
- exit on first error
- support out-of-tree builds O=...
- scripts/mod/modpost: make the namespace a separate field when
exporting to Module.symvers (rather than symbol.NS)
- scripts/export_report.pl: update for new Module.symvers format
- include/linux/export.h: fixed style nits
- kernel/module.c: ensure namespaces are imported before taking a
reference to the owner module
- Documentation: document the Symbol Namespace feature and update
references to Module.symvers and EXPORT_SYMBOL*
This patch series was developed against v5.3-rc7.
[1] git grep "^EXPORT_SYMBOL\w*(" v5.3-rc7 | wc -l
[2] git grep "^EXPORT_SYMBOL\w*(" v4.17 | wc -l
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Matthias Maennich (12):
module: support reading multiple values per modinfo tag
export: explicitly align struct kernel_symbol
module: add support for symbol namespaces.
modpost: add support for symbol namespaces
module: add config option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
export: allow definition default namespaces in Makefiles or sources
modpost: add support for generating namespace dependencies
scripts: Coccinelle script for namespace dependencies.
docs: Add documentation for Symbol Namespaces
usb-storage: remove single-use define for debugging
RFC: usb-storage: export symbols in USB_STORAGE namespace
RFC: watchdog: export core symbols in WATCHDOG_CORE namespace
.gitignore | 1 +
Documentation/kbuild/modules.rst | 7 +-
Documentation/kbuild/namespaces.rst | 154 ++++++++++++++++++++
Documentation/kernel-hacking/hacking.rst | 18 +++
MAINTAINERS | 5 +
Makefile | 14 +-
arch/m68k/include/asm/export.h | 1 -
drivers/hwmon/ftsteutates.c | 1 +
drivers/hwmon/sch56xx-common.c | 1 +
drivers/rtc/rtc-abx80x.c | 1 +
drivers/usb/storage/Makefile | 2 +
drivers/usb/storage/alauda.c | 1 +
drivers/usb/storage/cypress_atacb.c | 1 +
drivers/usb/storage/datafab.c | 1 +
drivers/usb/storage/debug.h | 2 -
drivers/usb/storage/ene_ub6250.c | 1 +
drivers/usb/storage/freecom.c | 1 +
drivers/usb/storage/isd200.c | 1 +
drivers/usb/storage/jumpshot.c | 1 +
drivers/usb/storage/karma.c | 1 +
drivers/usb/storage/onetouch.c | 1 +
drivers/usb/storage/realtek_cr.c | 1 +
drivers/usb/storage/scsiglue.c | 2 +-
drivers/usb/storage/sddr09.c | 1 +
drivers/usb/storage/sddr55.c | 1 +
drivers/usb/storage/shuttle_usbat.c | 1 +
drivers/usb/storage/uas.c | 1 +
drivers/watchdog/armada_37xx_wdt.c | 1 +
drivers/watchdog/asm9260_wdt.c | 1 +
drivers/watchdog/aspeed_wdt.c | 1 +
drivers/watchdog/at91sam9_wdt.c | 1 +
drivers/watchdog/atlas7_wdt.c | 1 +
drivers/watchdog/bcm2835_wdt.c | 1 +
drivers/watchdog/bcm47xx_wdt.c | 1 +
drivers/watchdog/bcm7038_wdt.c | 1 +
drivers/watchdog/bcm_kona_wdt.c | 1 +
drivers/watchdog/bd70528_wdt.c | 1 +
drivers/watchdog/cadence_wdt.c | 1 +
drivers/watchdog/da9052_wdt.c | 1 +
drivers/watchdog/da9055_wdt.c | 1 +
drivers/watchdog/da9062_wdt.c | 1 +
drivers/watchdog/da9063_wdt.c | 1 +
drivers/watchdog/davinci_wdt.c | 1 +
drivers/watchdog/digicolor_wdt.c | 1 +
drivers/watchdog/dw_wdt.c | 1 +
drivers/watchdog/ebc-c384_wdt.c | 1 +
drivers/watchdog/ep93xx_wdt.c | 1 +
drivers/watchdog/ftwdt010_wdt.c | 1 +
drivers/watchdog/gpio_wdt.c | 1 +
drivers/watchdog/hpwdt.c | 1 +
drivers/watchdog/i6300esb.c | 1 +
drivers/watchdog/iTCO_wdt.c | 1 +
drivers/watchdog/ie6xx_wdt.c | 1 +
drivers/watchdog/imgpdc_wdt.c | 1 +
drivers/watchdog/imx2_wdt.c | 1 +
drivers/watchdog/intel-mid_wdt.c | 1 +
drivers/watchdog/it87_wdt.c | 1 +
drivers/watchdog/kempld_wdt.c | 1 +
drivers/watchdog/lpc18xx_wdt.c | 1 +
drivers/watchdog/max63xx_wdt.c | 1 +
drivers/watchdog/max77620_wdt.c | 1 +
drivers/watchdog/mei_wdt.c | 1 +
drivers/watchdog/mena21_wdt.c | 1 +
drivers/watchdog/menf21bmc_wdt.c | 1 +
drivers/watchdog/menz69_wdt.c | 1 +
drivers/watchdog/meson_gxbb_wdt.c | 1 +
drivers/watchdog/meson_wdt.c | 1 +
drivers/watchdog/mlx_wdt.c | 1 +
drivers/watchdog/moxart_wdt.c | 1 +
drivers/watchdog/mtk_wdt.c | 1 +
drivers/watchdog/ni903x_wdt.c | 1 +
drivers/watchdog/nic7018_wdt.c | 1 +
drivers/watchdog/npcm_wdt.c | 1 +
drivers/watchdog/of_xilinx_wdt.c | 1 +
drivers/watchdog/omap_wdt.c | 1 +
drivers/watchdog/pm8916_wdt.c | 1 +
drivers/watchdog/qcom-wdt.c | 1 +
drivers/watchdog/rave-sp-wdt.c | 1 +
drivers/watchdog/renesas_wdt.c | 1 +
drivers/watchdog/retu_wdt.c | 1 +
drivers/watchdog/rn5t618_wdt.c | 1 +
drivers/watchdog/rza_wdt.c | 1 +
drivers/watchdog/s3c2410_wdt.c | 1 +
drivers/watchdog/sama5d4_wdt.c | 1 +
drivers/watchdog/sirfsoc_wdt.c | 1 +
drivers/watchdog/softdog.c | 1 +
drivers/watchdog/sp5100_tco.c | 1 +
drivers/watchdog/sprd_wdt.c | 1 +
drivers/watchdog/st_lpc_wdt.c | 1 +
drivers/watchdog/stmp3xxx_rtc_wdt.c | 1 +
drivers/watchdog/stpmic1_wdt.c | 1 +
drivers/watchdog/sunxi_wdt.c | 1 +
drivers/watchdog/tangox_wdt.c | 1 +
drivers/watchdog/tegra_wdt.c | 1 +
drivers/watchdog/tqmx86_wdt.c | 1 +
drivers/watchdog/ts4800_wdt.c | 1 +
drivers/watchdog/ts72xx_wdt.c | 1 +
drivers/watchdog/twl4030_wdt.c | 1 +
drivers/watchdog/uniphier_wdt.c | 1 +
drivers/watchdog/via_wdt.c | 1 +
drivers/watchdog/w83627hf_wdt.c | 1 +
drivers/watchdog/watchdog_core.c | 10 +-
drivers/watchdog/wdat_wdt.c | 1 +
drivers/watchdog/wm831x_wdt.c | 1 +
drivers/watchdog/wm8350_wdt.c | 1 +
drivers/watchdog/xen_wdt.c | 1 +
drivers/watchdog/ziirave_wdt.c | 1 +
include/asm-generic/export.h | 14 +-
include/linux/export.h | 98 +++++++++++--
include/linux/module.h | 2 +
init/Kconfig | 13 ++
kernel/module.c | 67 ++++++++-
scripts/Makefile.modpost | 4 +-
scripts/coccinelle/misc/add_namespace.cocci | 23 +++
scripts/export_report.pl | 2 +-
scripts/mod/modpost.c | 150 ++++++++++++++++---
scripts/mod/modpost.h | 9 ++
scripts/nsdeps | 60 ++++++++
118 files changed, 697 insertions(+), 57 deletions(-)
create mode 100644 Documentation/kbuild/namespaces.rst
create mode 100644 scripts/coccinelle/misc/add_namespace.cocci
create mode 100644 scripts/nsdeps
--
2.23.0.187.g17f5b7556c-goog
Add support for symbols that are exported into namespaces. For that,
extract any namespace suffix from the symbol name. In addition, emit a
warning whenever a module refers to an exported symbol without
explicitly importing the namespace that it is defined in. This patch
consistently adds the namespace suffix to symbol names exported into
Module.symvers.
Example warning emitted by modpost in case of the above violation:
WARNING: module ums-usbat uses symbol usb_stor_resume from namespace
USB_STORAGE, but does not import it.
Co-developed-by: Martijn Coenen <[email protected]>
Signed-off-by: Martijn Coenen <[email protected]>
Reviewed-by: Joel Fernandes (Google) <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Matthias Maennich <[email protected]>
---
Documentation/kbuild/modules.rst | 7 ++-
scripts/export_report.pl | 2 +-
scripts/mod/modpost.c | 104 ++++++++++++++++++++++++++-----
scripts/mod/modpost.h | 7 +++
4 files changed, 101 insertions(+), 19 deletions(-)
diff --git a/Documentation/kbuild/modules.rst b/Documentation/kbuild/modules.rst
index 24e763482650..d2ae799237fd 100644
--- a/Documentation/kbuild/modules.rst
+++ b/Documentation/kbuild/modules.rst
@@ -470,9 +470,12 @@ build.
The syntax of the Module.symvers file is::
- <CRC> <Symbol> <module>
+ <CRC> <Symbol> <Namespace> <Module> <Export Type>
- 0x2d036834 scsi_remove_host drivers/scsi/scsi_mod
+ 0xe1cc2a05 usb_stor_suspend USB_STORAGE drivers/usb/storage/usb-storage EXPORT_SYMBOL_GPL
+
+ The fields are separated by tabs and values may be empty (e.g.
+ if no namespace is defined for an exported symbol).
For a kernel build without CONFIG_MODVERSIONS enabled, the CRC
would read 0x00000000.
diff --git a/scripts/export_report.pl b/scripts/export_report.pl
index 7d3030d03a25..548330e8c4e7 100755
--- a/scripts/export_report.pl
+++ b/scripts/export_report.pl
@@ -94,7 +94,7 @@ if (defined $opt{'o'}) {
#
while ( <$module_symvers> ) {
chomp;
- my (undef, $symbol, $module, $gpl) = split;
+ my (undef, $symbol, $namespace, $module, $gpl) = split('\t');
$SYMBOL { $symbol } = [ $module , "0" , $symbol, $gpl];
}
close($module_symvers);
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index f277e116e0eb..c2d49afaea1c 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -164,6 +164,7 @@ struct symbol {
struct module *module;
unsigned int crc;
int crc_valid;
+ const char *namespace;
unsigned int weak:1;
unsigned int vmlinux:1; /* 1 if symbol is defined in vmlinux */
unsigned int kernel:1; /* 1 if symbol is from kernel
@@ -233,6 +234,37 @@ static struct symbol *find_symbol(const char *name)
return NULL;
}
+static bool contains_namespace(struct namespace_list *list,
+ const char *namespace)
+{
+ struct namespace_list *ns_entry;
+
+ for (ns_entry = list; ns_entry != NULL; ns_entry = ns_entry->next)
+ if (strcmp(ns_entry->namespace, namespace) == 0)
+ return true;
+
+ return false;
+}
+
+static void add_namespace(struct namespace_list **list, const char *namespace)
+{
+ struct namespace_list *ns_entry;
+
+ if (!contains_namespace(*list, namespace)) {
+ ns_entry = NOFAIL(malloc(sizeof(struct namespace_list) +
+ strlen(namespace) + 1));
+ strcpy(ns_entry->namespace, namespace);
+ ns_entry->next = *list;
+ *list = ns_entry;
+ }
+}
+
+static bool module_imports_namespace(struct module *module,
+ const char *namespace)
+{
+ return contains_namespace(module->imported_namespaces, namespace);
+}
+
static const struct {
const char *str;
enum export export;
@@ -312,23 +344,39 @@ static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
return export_unknown;
}
+static const char *sym_extract_namespace(const char **symname)
+{
+ size_t n;
+ char *dupsymname;
+
+ n = strcspn(*symname, ".");
+ if (n < strlen(*symname) - 1) {
+ dupsymname = NOFAIL(strdup(*symname));
+ dupsymname[n] = '\0';
+ *symname = dupsymname;
+ return dupsymname + n + 1;
+ }
+
+ return NULL;
+}
+
/**
* Add an exported symbol - it may have already been added without a
* CRC, in this case just update the CRC
**/
-static struct symbol *sym_add_exported(const char *name, struct module *mod,
- enum export export)
+static struct symbol *sym_add_exported(const char *name, const char *namespace,
+ struct module *mod, enum export export)
{
struct symbol *s = find_symbol(name);
if (!s) {
s = new_symbol(name, mod, export);
+ s->namespace = namespace;
} else {
if (!s->preloaded) {
- warn("%s: '%s' exported twice. Previous export "
- "was in %s%s\n", mod->name, name,
- s->module->name,
- is_vmlinux(s->module->name) ?"":".ko");
+ warn("%s: '%s' exported twice. Previous export was in %s%s\n",
+ mod->name, name, s->module->name,
+ is_vmlinux(s->module->name) ? "" : ".ko");
} else {
/* In case Module.symvers was out of date */
s->module = mod;
@@ -620,6 +668,7 @@ static void handle_modversions(struct module *mod, struct elf_info *info,
unsigned int crc;
enum export export;
bool is_crc = false;
+ const char *name, *namespace;
if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
strstarts(symname, "__ksymtab"))
@@ -691,8 +740,9 @@ static void handle_modversions(struct module *mod, struct elf_info *info,
default:
/* All exported symbols */
if (strstarts(symname, "__ksymtab_")) {
- sym_add_exported(symname + strlen("__ksymtab_"), mod,
- export);
+ name = symname + strlen("__ksymtab_");
+ namespace = sym_extract_namespace(&name);
+ sym_add_exported(name, namespace, mod, export);
}
if (strcmp(symname, "init_module") == 0)
mod->has_init = 1;
@@ -1943,6 +1993,7 @@ static void read_symbols(const char *modname)
const char *symname;
char *version;
char *license;
+ char *namespace;
struct module *mod;
struct elf_info info = { };
Elf_Sym *sym;
@@ -1974,6 +2025,12 @@ static void read_symbols(const char *modname)
license = get_next_modinfo(&info, "license", license);
}
+ namespace = get_modinfo(&info, "import_ns");
+ while (namespace) {
+ add_namespace(&mod->imported_namespaces, namespace);
+ namespace = get_next_modinfo(&info, "import_ns", namespace);
+ }
+
for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
symname = remove_dot(info.strtab + sym->st_name);
@@ -2118,6 +2175,13 @@ static int check_exports(struct module *mod)
basename++;
else
basename = mod->name;
+
+ if (exp->namespace &&
+ !module_imports_namespace(mod, exp->namespace)) {
+ warn("module %s uses symbol %s from namespace %s, but does not import it.\n",
+ basename, exp->name, exp->namespace);
+ }
+
if (!mod->gpl_compatible)
check_for_gpl_usage(exp->export, basename, exp->name);
check_for_unused(exp->export, basename, exp->name);
@@ -2341,7 +2405,7 @@ static void read_dump(const char *fname, unsigned int kernel)
return;
while ((line = get_next_line(&pos, file, size))) {
- char *symname, *modname, *d, *export, *end;
+ char *symname, *namespace, *modname, *d, *export, *end;
unsigned int crc;
struct module *mod;
struct symbol *s;
@@ -2349,7 +2413,10 @@ static void read_dump(const char *fname, unsigned int kernel)
if (!(symname = strchr(line, '\t')))
goto fail;
*symname++ = '\0';
- if (!(modname = strchr(symname, '\t')))
+ if (!(namespace = strchr(symname, '\t')))
+ goto fail;
+ *namespace++ = '\0';
+ if (!(modname = strchr(namespace, '\t')))
goto fail;
*modname++ = '\0';
if ((export = strchr(modname, '\t')) != NULL)
@@ -2366,7 +2433,8 @@ static void read_dump(const char *fname, unsigned int kernel)
mod = new_module(modname);
mod->skip = 1;
}
- s = sym_add_exported(symname, mod, export_no(export));
+ s = sym_add_exported(symname, namespace, mod,
+ export_no(export));
s->kernel = kernel;
s->preloaded = 1;
sym_update_crc(symname, mod, crc, export_no(export));
@@ -2395,16 +2463,20 @@ static void write_dump(const char *fname)
{
struct buffer buf = { };
struct symbol *symbol;
+ const char *namespace;
int n;
for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
symbol = symbolhash[n];
while (symbol) {
- if (dump_sym(symbol))
- buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
- symbol->crc, symbol->name,
- symbol->module->name,
- export_str(symbol->export));
+ if (dump_sym(symbol)) {
+ namespace = symbol->namespace;
+ buf_printf(&buf, "0x%08x\t%s\t%s\t%s\t%s\n",
+ symbol->crc, symbol->name,
+ namespace ? namespace : "",
+ symbol->module->name,
+ export_str(symbol->export));
+ }
symbol = symbol->next;
}
}
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index 8453d6ac2f77..9626bf3e7424 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -109,6 +109,11 @@ buf_printf(struct buffer *buf, const char *fmt, ...);
void
buf_write(struct buffer *buf, const char *s, int len);
+struct namespace_list {
+ struct namespace_list *next;
+ char namespace[0];
+};
+
struct module {
struct module *next;
const char *name;
@@ -121,6 +126,8 @@ struct module {
struct buffer dev_table_buf;
char srcversion[25];
int is_dot_o;
+ // Actual imported namespaces
+ struct namespace_list *imported_namespaces;
};
struct elf_info {
--
2.23.0.187.g17f5b7556c-goog
Similar to modpost's get_next_modinfo(), introduce get_next_modinfo() in
kernel/module.c to acquire any further values associated with the same
modinfo tag name. That is useful for any tags that have multiple
occurrences (such as 'alias'), but is in particular introduced here as
part of the symbol namespaces patch series to read the (potentially)
multiple namespaces a module is importing.
Reviewed-by: Joel Fernandes (Google) <[email protected]>
Reviewed-by: Martijn Coenen <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Matthias Maennich <[email protected]>
---
kernel/module.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/kernel/module.c b/kernel/module.c
index 9ee93421269c..3ee507c0a92f 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2481,7 +2481,8 @@ static char *next_string(char *string, unsigned long *secsize)
return string;
}
-static char *get_modinfo(struct load_info *info, const char *tag)
+static char *get_next_modinfo(const struct load_info *info, const char *tag,
+ char *prev)
{
char *p;
unsigned int taglen = strlen(tag);
@@ -2492,13 +2493,25 @@ static char *get_modinfo(struct load_info *info, const char *tag)
* get_modinfo() calls made before rewrite_section_headers()
* must use sh_offset, as sh_addr isn't set!
*/
- for (p = (char *)info->hdr + infosec->sh_offset; p; p = next_string(p, &size)) {
+ char *modinfo = (char *)info->hdr + infosec->sh_offset;
+
+ if (prev) {
+ size -= prev - modinfo;
+ modinfo = next_string(prev, &size);
+ }
+
+ for (p = modinfo; p; p = next_string(p, &size)) {
if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
return p + taglen + 1;
}
return NULL;
}
+static char *get_modinfo(const struct load_info *info, const char *tag)
+{
+ return get_next_modinfo(info, tag, NULL);
+}
+
static void setup_modinfo(struct module *mod, struct load_info *info)
{
struct module_attribute *attr;
--
2.23.0.187.g17f5b7556c-goog
The EXPORT_SYMBOL_NS() and EXPORT_SYMBOL_NS_GPL() macros can be used to
export a symbol to a specific namespace. There are no _GPL_FUTURE and
_UNUSED variants because these are currently unused, and I'm not sure
they are necessary.
I didn't add EXPORT_SYMBOL_NS() for ASM exports; this patch sets the
namespace of ASM exports to NULL by default. In case of relative
references, it will be relocatable to NULL. If there's a need, this
should be pretty easy to add.
A module that wants to use a symbol exported to a namespace must add a
MODULE_IMPORT_NS() statement to their module code; otherwise, modpost
will complain when building the module, and the kernel module loader
will emit an error and fail when loading the module.
MODULE_IMPORT_NS() adds a modinfo tag 'import_ns' to the module. That
tag can be observed by the modinfo command, modpost and kernel/module.c
at the time of loading the module.
The ELF symbols are renamed to include the namespace with an asm label;
for example, symbol 'usb_stor_suspend' in namespace USB_STORAGE becomes
'usb_stor_suspend.USB_STORAGE'. This allows modpost to do namespace
checking, without having to go through all the effort of parsing ELF and
relocation records just to get to the struct kernel_symbols.
On x86_64 I saw no difference in binary size (compression), but at
runtime this will require a word of memory per export to hold the
namespace. An alternative could be to store namespaced symbols in their
own section and use a separate 'struct namespaced_kernel_symbol' for
that section, at the cost of making the module loader more complex.
Co-developed-by: Martijn Coenen <[email protected]>
Signed-off-by: Martijn Coenen <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Matthias Maennich <[email protected]>
---
include/asm-generic/export.h | 6 +--
include/linux/export.h | 91 +++++++++++++++++++++++++++++-------
include/linux/module.h | 2 +
kernel/module.c | 43 +++++++++++++++++
4 files changed, 123 insertions(+), 19 deletions(-)
diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h
index 63f54907317b..e2b5d0f569d3 100644
--- a/include/asm-generic/export.h
+++ b/include/asm-generic/export.h
@@ -17,11 +17,11 @@
.macro __put, val, name
#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
- .long \val - ., \name - .
+ .long \val - ., \name - ., 0 - .
#elif defined(CONFIG_64BIT)
- .quad \val, \name
+ .quad \val, \name, 0
#else
- .long \val, \name
+ .long \val, \name, 0
#endif
.endm
diff --git a/include/linux/export.h b/include/linux/export.h
index 28a4d2150689..d59461e71478 100644
--- a/include/linux/export.h
+++ b/include/linux/export.h
@@ -20,6 +20,8 @@ extern struct module __this_module;
#ifdef CONFIG_MODULES
+#define NS_SEPARATOR "."
+
#if defined(__KERNEL__) && !defined(__GENKSYMS__)
#ifdef CONFIG_MODVERSIONS
/* Mark the CRC weak since genksyms apparently decides not to
@@ -29,13 +31,13 @@ extern struct module __this_module;
asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \
" .weak __crc_" #sym " \n" \
" .long __crc_" #sym " - . \n" \
- " .previous \n");
+ " .previous \n")
#else
#define __CRC_SYMBOL(sym, sec) \
asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \
" .weak __crc_" #sym " \n" \
" .long __crc_" #sym " \n" \
- " .previous \n");
+ " .previous \n")
#endif
#else
#define __CRC_SYMBOL(sym, sec)
@@ -49,6 +51,16 @@ extern struct module __this_module;
* absolute relocations that require runtime processing on relocatable
* kernels.
*/
+#define __KSYMTAB_ENTRY_NS(sym, sec, ns) \
+ __ADDRESSABLE(sym) \
+ asm(" .section \"___ksymtab" sec "+" #sym "\", \"a\" \n" \
+ " .balign 4 \n" \
+ "__ksymtab_" #sym NS_SEPARATOR #ns ": \n" \
+ " .long " #sym "- . \n" \
+ " .long __kstrtab_" #sym "- . \n" \
+ " .long __kstrtab_ns_" #sym "- . \n" \
+ " .previous \n")
+
#define __KSYMTAB_ENTRY(sym, sec) \
__ADDRESSABLE(sym) \
asm(" .section \"___ksymtab" sec "+" #sym "\", \"a\" \n" \
@@ -56,32 +68,53 @@ extern struct module __this_module;
"__ksymtab_" #sym ": \n" \
" .long " #sym "- . \n" \
" .long __kstrtab_" #sym "- . \n" \
+ " .long 0 - . \n" \
" .previous \n")
struct kernel_symbol {
int value_offset;
int name_offset;
+ int namespace_offset;
};
#else
+#define __KSYMTAB_ENTRY_NS(sym, sec, ns) \
+ static const struct kernel_symbol __ksymtab_##sym##__##ns \
+ asm("__ksymtab_" #sym NS_SEPARATOR #ns) \
+ __attribute__((section("___ksymtab" sec "+" #sym), used)) \
+ __aligned(sizeof(void *)) \
+ = { (unsigned long)&sym, __kstrtab_##sym, __kstrtab_ns_##sym }
+
#define __KSYMTAB_ENTRY(sym, sec) \
static const struct kernel_symbol __ksymtab_##sym \
+ asm("__ksymtab_" #sym) \
__attribute__((section("___ksymtab" sec "+" #sym), used)) \
__aligned(sizeof(void *)) \
- = { (unsigned long)&sym, __kstrtab_##sym }
+ = { (unsigned long)&sym, __kstrtab_##sym, NULL }
struct kernel_symbol {
unsigned long value;
const char *name;
+ const char *namespace;
};
#endif
-/* For every exported symbol, place a struct in the __ksymtab section */
-#define ___EXPORT_SYMBOL(sym, sec) \
+#define ___export_symbol_common(sym, sec) \
extern typeof(sym) sym; \
- __CRC_SYMBOL(sym, sec) \
+ __CRC_SYMBOL(sym, sec); \
static const char __kstrtab_##sym[] \
__attribute__((section("__ksymtab_strings"), used, aligned(1))) \
- = #sym; \
+ = #sym \
+
+/* For every exported symbol, place a struct in the __ksymtab section */
+#define ___EXPORT_SYMBOL_NS(sym, sec, ns) \
+ ___export_symbol_common(sym, sec); \
+ static const char __kstrtab_ns_##sym[] \
+ __attribute__((section("__ksymtab_strings"), used, aligned(1))) \
+ = #ns; \
+ __KSYMTAB_ENTRY_NS(sym, sec, ns)
+
+#define ___EXPORT_SYMBOL(sym, sec) \
+ ___export_symbol_common(sym, sec); \
__KSYMTAB_ENTRY(sym, sec)
#if defined(__DISABLE_EXPORTS)
@@ -91,6 +124,7 @@ struct kernel_symbol {
* be reused in other execution contexts such as the UEFI stub or the
* decompressor.
*/
+#define __EXPORT_SYMBOL_NS(sym, sec, ns)
#define __EXPORT_SYMBOL(sym, sec)
#elif defined(CONFIG_TRIM_UNUSED_KSYMS)
@@ -117,18 +151,26 @@ struct kernel_symbol {
#define __cond_export_sym_1(sym, sec) ___EXPORT_SYMBOL(sym, sec)
#define __cond_export_sym_0(sym, sec) /* nothing */
+#define __EXPORT_SYMBOL_NS(sym, sec, ns) \
+ __ksym_marker(sym); \
+ __cond_export_ns_sym(sym, sec, ns, __is_defined(__KSYM_##sym))
+#define __cond_export_ns_sym(sym, sec, ns, conf) \
+ ___cond_export_ns_sym(sym, sec, ns, conf)
+#define ___cond_export_ns_sym(sym, sec, ns, enabled) \
+ __cond_export_ns_sym_##enabled(sym, sec, ns)
+#define __cond_export_ns_sym_1(sym, sec, ns) ___EXPORT_SYMBOL_NS(sym, sec, ns)
+#define __cond_export_ns_sym_0(sym, sec, ns) /* nothing */
+
#else
+#define __EXPORT_SYMBOL_NS ___EXPORT_SYMBOL_NS
#define __EXPORT_SYMBOL ___EXPORT_SYMBOL
#endif
-#define EXPORT_SYMBOL(sym) \
- __EXPORT_SYMBOL(sym, "")
-
-#define EXPORT_SYMBOL_GPL(sym) \
- __EXPORT_SYMBOL(sym, "_gpl")
-
-#define EXPORT_SYMBOL_GPL_FUTURE(sym) \
- __EXPORT_SYMBOL(sym, "_gpl_future")
+#define EXPORT_SYMBOL(sym) __EXPORT_SYMBOL(sym, "")
+#define EXPORT_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_gpl")
+#define EXPORT_SYMBOL_GPL_FUTURE(sym) __EXPORT_SYMBOL(sym, "_gpl_future")
+#define EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL_NS(sym, "", ns)
+#define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL_NS(sym, "_gpl", ns)
#ifdef CONFIG_UNUSED_SYMBOLS
#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused")
@@ -138,11 +180,28 @@ struct kernel_symbol {
#define EXPORT_UNUSED_SYMBOL_GPL(sym)
#endif
-#endif /* __GENKSYMS__ */
+#endif /* __KERNEL__ && !__GENKSYMS__ */
+
+#if defined(__GENKSYMS__)
+/*
+ * When we're running genksyms, ignore the namespace and make the _NS
+ * variants look like the normal ones. There are two reasons for this:
+ * 1) In the normal definition of EXPORT_SYMBOL_NS, the 'ns' macro
+ * argument is itself not expanded because it's always tokenized or
+ * concatenated; but when running genksyms, a blank definition of the
+ * macro does allow the argument to be expanded; if a namespace
+ * happens to collide with a #define, this can cause issues.
+ * 2) There's no need to modify genksyms to deal with the _NS variants
+ */
+#define EXPORT_SYMBOL_NS(sym, ns) EXPORT_SYMBOL(sym)
+#define EXPORT_SYMBOL_NS_GPL(sym, ns) EXPORT_SYMBOL_GPL(sym)
+#endif
#else /* !CONFIG_MODULES... */
#define EXPORT_SYMBOL(sym)
+#define EXPORT_SYMBOL_NS(sym, ns)
+#define EXPORT_SYMBOL_NS_GPL(sym, ns)
#define EXPORT_SYMBOL_GPL(sym)
#define EXPORT_SYMBOL_GPL_FUTURE(sym)
#define EXPORT_UNUSED_SYMBOL(sym)
diff --git a/include/linux/module.h b/include/linux/module.h
index 1455812dd325..b3611e749f72 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -280,6 +280,8 @@ struct notifier_block;
#ifdef CONFIG_MODULES
+#define MODULE_IMPORT_NS(ns) MODULE_INFO(import_ns, #ns)
+
extern int modules_disabled; /* for sysctl */
/* Get/put a kernel symbol (calls must be symmetric) */
void *__symbol_get(const char *symbol);
diff --git a/kernel/module.c b/kernel/module.c
index 3ee507c0a92f..6bb9b938f9c7 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -544,6 +544,15 @@ static const char *kernel_symbol_name(const struct kernel_symbol *sym)
#endif
}
+static const char *kernel_symbol_namespace(const struct kernel_symbol *sym)
+{
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+ return offset_to_ptr(&sym->namespace_offset);
+#else
+ return sym->namespace;
+#endif
+}
+
static int cmp_name(const void *va, const void *vb)
{
const char *a;
@@ -1379,6 +1388,34 @@ static inline int same_magic(const char *amagic, const char *bmagic,
}
#endif /* CONFIG_MODVERSIONS */
+static char *get_modinfo(const struct load_info *info, const char *tag);
+static char *get_next_modinfo(const struct load_info *info, const char *tag,
+ char *prev);
+
+static int verify_namespace_is_imported(const struct load_info *info,
+ const struct kernel_symbol *sym,
+ struct module *mod)
+{
+ const char *namespace;
+ char *imported_namespace;
+
+ namespace = kernel_symbol_namespace(sym);
+ if (namespace) {
+ imported_namespace = get_modinfo(info, "import_ns");
+ while (imported_namespace) {
+ if (strcmp(namespace, imported_namespace) == 0)
+ return 0;
+ imported_namespace = get_next_modinfo(
+ info, "import_ns", imported_namespace);
+ }
+ pr_err("%s: module uses symbol (%s) from namespace %s, but does not import it.\n",
+ mod->name, kernel_symbol_name(sym), namespace);
+ return -EINVAL;
+ }
+ return 0;
+}
+
+
/* Resolve a symbol for this module. I.e. if we find one, record usage. */
static const struct kernel_symbol *resolve_symbol(struct module *mod,
const struct load_info *info,
@@ -1407,6 +1444,12 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
goto getname;
}
+ err = verify_namespace_is_imported(info, sym, mod);
+ if (err) {
+ sym = ERR_PTR(err);
+ goto getname;
+ }
+
err = ref_module(mod, owner);
if (err) {
sym = ERR_PTR(err);
--
2.23.0.187.g17f5b7556c-goog
A script that uses the '<module>.ns_deps' files generated by modpost to
automatically add the required symbol namespace dependencies to each
module.
Usage:
1) Move some symbols to a namespace with EXPORT_SYMBOL_NS() or define
DEFAULT_SYMBOL_NAMESPACE
2) Run 'make' (or 'make modules') and get warnings about modules not
importing that namespace.
3) Run 'make nsdeps' to automatically add required import statements
to said modules.
This makes it easer for subsystem maintainers to introduce and maintain
symbol namespaces into their codebase.
Co-developed-by: Martijn Coenen <[email protected]>
Signed-off-by: Martijn Coenen <[email protected]>
Acked-by: Julia Lawall <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Matthias Maennich <[email protected]>
---
MAINTAINERS | 5 ++
Makefile | 12 +++++
scripts/Makefile.modpost | 4 +-
scripts/coccinelle/misc/add_namespace.cocci | 23 ++++++++
scripts/nsdeps | 60 +++++++++++++++++++++
5 files changed, 103 insertions(+), 1 deletion(-)
create mode 100644 scripts/coccinelle/misc/add_namespace.cocci
create mode 100644 scripts/nsdeps
diff --git a/MAINTAINERS b/MAINTAINERS
index e7a47b5210fd..3b170c11a0e6 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11436,6 +11436,11 @@ S: Maintained
T: git git://git.kernel.org/pub/scm/linux/kernel/git/wtarreau/nolibc.git
F: tools/include/nolibc/
+NSDEPS
+M: Matthias Maennich <[email protected]>
+S: Maintained
+F: scripts/nsdeps
+
NTB AMD DRIVER
M: Shyam Sundar S K <[email protected]>
L: [email protected]
diff --git a/Makefile b/Makefile
index 0cdb957ae2c3..573e90e738ad 100644
--- a/Makefile
+++ b/Makefile
@@ -1500,6 +1500,9 @@ help:
@echo ' headerdep - Detect inclusion cycles in headers'
@echo ' coccicheck - Check with Coccinelle'
@echo ''
+ @echo 'Tools:'
+ @echo ' nsdeps - Generate missing symbol namespace dependencies'
+ @echo ''
@echo 'Kernel selftest:'
@echo ' kselftest - Build and run kernel selftest (run as root)'
@echo ' Build, install, and boot kernel before'
@@ -1687,6 +1690,15 @@ quiet_cmd_tags = GEN $@
tags TAGS cscope gtags: FORCE
$(call cmd,tags)
+# Script to generate missing namespace dependencies
+# ---------------------------------------------------------------------------
+
+PHONY += nsdeps
+
+nsdeps:
+ $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost nsdeps
+ $(Q)$(CONFIG_SHELL) $(srctree)/scripts/$@
+
# Scripts to check various things for consistency
# ---------------------------------------------------------------------------
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index 26e6574ecd08..743fe3a2e885 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -56,7 +56,8 @@ MODPOST = scripts/mod/modpost \
$(if $(KBUILD_EXTMOD),$(addprefix -e ,$(KBUILD_EXTRA_SYMBOLS))) \
$(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \
$(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \
- $(if $(KBUILD_MODPOST_WARN),-w)
+ $(if $(KBUILD_MODPOST_WARN),-w) \
+ $(if $(filter nsdeps,$(MAKECMDGOALS)),-d)
ifdef MODPOST_VMLINUX
@@ -134,6 +135,7 @@ $(modules): %.ko :%.o %.mod.o FORCE
targets += $(modules)
+nsdeps: __modpost
# Add FORCE to the prequisites of a target to force it to be always rebuilt.
# ---------------------------------------------------------------------------
diff --git a/scripts/coccinelle/misc/add_namespace.cocci b/scripts/coccinelle/misc/add_namespace.cocci
new file mode 100644
index 000000000000..c832bb6445a8
--- /dev/null
+++ b/scripts/coccinelle/misc/add_namespace.cocci
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+/// Adds missing MODULE_IMPORT_NS statements to source files
+///
+/// This script is usually called from scripts/nsdeps with -D ns=<namespace> to
+/// add a missing namespace tag to a module source file.
+///
+
+@has_ns_import@
+declarer name MODULE_IMPORT_NS;
+identifier virtual.ns;
+@@
+MODULE_IMPORT_NS(ns);
+
+// Add missing imports, but only adjacent to a MODULE_LICENSE statement.
+// That ensures we are adding it only to the main module source file.
+@do_import depends on !has_ns_import@
+declarer name MODULE_LICENSE;
+expression license;
+identifier virtual.ns;
+@@
+MODULE_LICENSE(license);
++ MODULE_IMPORT_NS(ns);
diff --git a/scripts/nsdeps b/scripts/nsdeps
new file mode 100644
index 000000000000..75dcf79a11ed
--- /dev/null
+++ b/scripts/nsdeps
@@ -0,0 +1,60 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Linux kernel symbol namespace import generator
+#
+# This script requires a minimum spatch version.
+SPATCH_REQ_VERSION="1.0.4"
+
+DIR="$(dirname $(readlink -f $0))/.."
+SPATCH="`which ${SPATCH:=spatch}`"
+if [ ! -x "$SPATCH" ]; then
+ echo 'spatch is part of the Coccinelle project and is available at http://coccinelle.lip6.fr/'
+ exit 1
+fi
+
+SPATCH_REQ_VERSION_NUM=$(echo $SPATCH_REQ_VERSION | ${DIR}/scripts/ld-version.sh)
+SPATCH_VERSION=$($SPATCH --version | head -1 | awk '{print $3}')
+SPATCH_VERSION_NUM=$(echo $SPATCH_VERSION | ${DIR}/scripts/ld-version.sh)
+
+if [ "$SPATCH_VERSION_NUM" -lt "$SPATCH_REQ_VERSION_NUM" ] ; then
+ echo "spatch needs to be version $SPATCH_REQ_VERSION or higher"
+ exit 1
+fi
+
+set -e
+
+generate_deps_for_ns() {
+ $SPATCH --very-quiet --in-place --sp-file \
+ $srctree/scripts/coccinelle/misc/add_namespace.cocci -D ns=$1 $2
+}
+
+generate_deps() {
+ local mod_name=`basename $@ .ko`
+ local mod_file=`echo $@ | sed -e 's/\.ko/\.mod/'`
+ local ns_deps_file=`echo $@ | sed -e 's/\.ko/\.ns_deps/'`
+ if [ ! -f "$ns_deps_file" ]; then return; fi
+ local mod_source_files=`cat $mod_file | sed -n 1p \
+ | sed -e 's/\.o/\.c/g' \
+ | sed "s/[^ ]* */${srctree}\/&/g"`
+ for ns in `cat $ns_deps_file`; do
+ echo "Adding namespace $ns to module $mod_name (if needed)."
+ generate_deps_for_ns $ns $mod_source_files
+ # sort the imports
+ for source_file in $mod_source_files; do
+ sed '/MODULE_IMPORT_NS/Q' $source_file > ${source_file}.tmp
+ offset=$(wc -l ${source_file}.tmp | awk '{print $1;}')
+ cat $source_file | grep MODULE_IMPORT_NS | sort -u >> ${source_file}.tmp
+ tail -n +$((offset +1)) ${source_file} | grep -v MODULE_IMPORT_NS >> ${source_file}.tmp
+ if ! diff -q ${source_file} ${source_file}.tmp; then
+ mv ${source_file}.tmp ${source_file}
+ else
+ rm ${source_file}.tmp
+ fi
+ done
+ done
+}
+
+for f in `cat $objtree/modules.order`; do
+ generate_deps $f
+done
+
--
2.23.0.187.g17f5b7556c-goog
USB_STORAGE was defined as "usb-storage: " and used in a single location
as argument to printk. In order to be able to use the name
'USB_STORAGE', drop the definition and use the string directly for the
printk call.
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Matthias Maennich <[email protected]>
---
drivers/usb/storage/debug.h | 2 --
drivers/usb/storage/scsiglue.c | 2 +-
2 files changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/usb/storage/debug.h b/drivers/usb/storage/debug.h
index 6d64f342f587..16ce06039a4d 100644
--- a/drivers/usb/storage/debug.h
+++ b/drivers/usb/storage/debug.h
@@ -29,8 +29,6 @@
#include <linux/kernel.h>
-#define USB_STORAGE "usb-storage: "
-
#ifdef CONFIG_USB_STORAGE_DEBUG
void usb_stor_show_command(const struct us_data *us, struct scsi_cmnd *srb);
void usb_stor_show_sense(const struct us_data *us, unsigned char key,
diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
index 05b80211290d..df4de8323eff 100644
--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -379,7 +379,7 @@ static int queuecommand_lck(struct scsi_cmnd *srb,
/* check for state-transition errors */
if (us->srb != NULL) {
- printk(KERN_ERR USB_STORAGE "Error in %s: us->srb = %p\n",
+ printk(KERN_ERR "usb-storage: Error in %s: us->srb = %p\n",
__func__, us->srb);
return SCSI_MLQUEUE_HOST_BUSY;
}
--
2.23.0.187.g17f5b7556c-goog
To avoid excessive usage of EXPORT_SYMBOL_NS(sym, MY_NAMESPACE), where
MY_NAMESPACE will always be the namespace we are exporting to, allow
exporting all definitions of EXPORT_SYMBOL() and friends by defining
DEFAULT_SYMBOL_NAMESPACE.
For example, to export all symbols defined in usb-common into the
namespace USB_COMMON, add a line like this to drivers/usb/common/Makefile:
ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=USB_COMMON
That is equivalent to changing all EXPORT_SYMBOL(sym) definitions to
EXPORT_SYMBOL_NS(sym, USB_COMMON). Subsequently all symbol namespaces
functionality will apply.
Another way of making use of this feature is to define the namespace
within source or header files similar to how TRACE_SYSTEM defines are
used:
#undef DEFAULT_SYMBOL_NAMESPACE
#define DEFAULT_SYMBOL_NAMESPACE USB_COMMON
Please note that, as opposed to TRACE_SYSTEM, DEFAULT_SYMBOL_NAMESPACE
has to be defined before including include/linux/export.h.
If DEFAULT_SYMBOL_NAMESPACE is defined, a symbol can still be exported
to another namespace by using EXPORT_SYMBOL_NS() and friends with
explicitly specifying the namespace.
Suggested-by: Arnd Bergmann <[email protected]>
Reviewed-by: Martijn Coenen <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Matthias Maennich <[email protected]>
---
include/linux/export.h | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/include/linux/export.h b/include/linux/export.h
index d59461e71478..2c5468d8ea9a 100644
--- a/include/linux/export.h
+++ b/include/linux/export.h
@@ -166,6 +166,12 @@ struct kernel_symbol {
#define __EXPORT_SYMBOL ___EXPORT_SYMBOL
#endif
+#ifdef DEFAULT_SYMBOL_NAMESPACE
+#undef __EXPORT_SYMBOL
+#define __EXPORT_SYMBOL(sym, sec) \
+ __EXPORT_SYMBOL_NS(sym, sec, DEFAULT_SYMBOL_NAMESPACE)
+#endif
+
#define EXPORT_SYMBOL(sym) __EXPORT_SYMBOL(sym, "")
#define EXPORT_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_gpl")
#define EXPORT_SYMBOL_GPL_FUTURE(sym) __EXPORT_SYMBOL(sym, "_gpl_future")
--
2.23.0.187.g17f5b7556c-goog
Describe using Symbol Namespaces from a perspective of a user. I.e.
module authors or subsystem maintainers.
Signed-off-by: Matthias Maennich <[email protected]>
---
Documentation/kbuild/namespaces.rst | 154 +++++++++++++++++++++++
Documentation/kernel-hacking/hacking.rst | 18 +++
2 files changed, 172 insertions(+)
create mode 100644 Documentation/kbuild/namespaces.rst
diff --git a/Documentation/kbuild/namespaces.rst b/Documentation/kbuild/namespaces.rst
new file mode 100644
index 000000000000..982ed7b568ac
--- /dev/null
+++ b/Documentation/kbuild/namespaces.rst
@@ -0,0 +1,154 @@
+=================
+Symbol Namespaces
+=================
+
+The following document describes how to use Symbol Namespaces to structure the
+export surface of in-kernel symbols exported through the family of
+EXPORT_SYMBOL() macros.
+
+.. Table of Contents
+
+ === 1 Introduction
+ === 2 How to define Symbol Namespaces
+ --- 2.1 Using the EXPORT_SYMBOL macros
+ --- 2.2 Using the DEFAULT_SYMBOL_NAMESPACE define
+ === 3 How to use Symbols exported in Namespaces
+ === 4 Loading Modules that use namespaced Symbols
+ === 5 Automatically creating MODULE_IMPORT_NS statements
+
+1. Introduction
+===============
+
+Symbol Namespaces have been introduced as a means to structure the export
+surface of the in-kernel API. It allows subsystem maintainers to partition
+their exported symbols into separate namespaces. That is useful for
+documentation purposes (think of the SUBSYSTEM_DEBUG namespace) as well as for
+limiting the availability of a set of symbols for use in other parts of the
+kernel. As of today, modules that make use of symbols exported into namespaces,
+are required to import the namespace. Otherwise the kernel will, depending on
+its configuration, reject loading the module or warn about a missing import.
+
+2. How to define Symbol Namespaces
+==================================
+
+Symbols can be exported into namespace using different methods. All of them are
+changing the way EXPORT_SYMBOL and friends are instrumented to create ksymtab
+entries.
+
+2.1 Using the EXPORT_SYMBOL macros
+==================================
+
+In addition to the macros EXPORT_SYMBOL() and EXPORT_SYMBOL_GPL(), that allow
+exporting of kernel symbols to the kernel symbol table, variants of these are
+available to export symbols into a certain namespace: EXPORT_SYMBOL_NS() and
+EXPORT_SYMBOL_NS_GPL(). They take one additional argument: the namespace.
+Please note that due to macro expansion that argument needs to be a
+preprocessor symbol. E.g. to export the symbol `usb_stor_suspend` into the
+namespace `USB_STORAGE`, use::
+
+ EXPORT_SYMBOL_NS(usb_stor_suspend, USB_STORAGE);
+
+The corresponding ksymtab entry struct `kernel_symbol` will have the member
+`namespace` set accordingly. A symbol that is exported without a namespace will
+refer to `NULL`. There is no default namespace if none is defined. `modpost`
+and kernel/module.c make use the namespace at build time or module load time,
+respectively.
+
+2.2 Using the DEFAULT_SYMBOL_NAMESPACE define
+=============================================
+
+Defining namespaces for all symbols of a subsystem can be very verbose and may
+become hard to maintain. Therefore a default define (DEFAULT_SYMBOL_NAMESPACE)
+is been provided, that, if set, will become the default for all EXPORT_SYMBOL()
+and EXPORT_SYMBOL_GPL() macro expansions that do not specify a namespace.
+
+There are multiple ways of specifying this define and it depends on the
+subsystem and the maintainer's preference, which one to use. The first option
+is to define the default namespace in the `Makefile` of the subsystem. E.g. to
+export all symbols defined in usb-common into the namespace USB_COMMON, add a
+line like this to drivers/usb/common/Makefile::
+
+ ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=USB_COMMON
+
+That will affect all EXPORT_SYMBOL() and EXPORT_SYMBOL_GPL() statements. A
+symbol exported with EXPORT_SYMBOL_NS() while this definition is present, will
+still be exported into the namespace that is passed as the namespace argument
+as this argument has preference over a default symbol namespace.
+
+A second option to define the default namespace is directly in the compilation
+unit as preprocessor statement. The above example would then read::
+
+ #undef DEFAULT_SYMBOL_NAMESPACE
+ #define DEFAULT_SYMBOL_NAMESPACE USB_COMMON
+
+within the corresponding compilation unit before any EXPORT_SYMBOL macro is
+used.
+
+3. How to use Symbols exported in Namespaces
+============================================
+
+In order to use symbols that are exported into namespaces, kernel modules need
+to explicitly import these namespaces. Otherwise the kernel might reject to
+load the module. The module code is required to use the macro MODULE_IMPORT_NS
+for the namespaces it uses symbols from. E.g. a module using the
+usb_stor_suspend symbol from above, needs to import the namespace USB_STORAGE
+using a statement like::
+
+ MODULE_IMPORT_NS(USB_STORAGE);
+
+This will create a `modinfo` tag in the module for each imported namespace.
+This has the side effect, that the imported namespaces of a module can be
+inspected with modinfo::
+
+ $ modinfo drivers/usb/storage/ums-karma.ko
+ [...]
+ import_ns: USB_STORAGE
+ [...]
+
+
+It is advisable to add the MODULE_IMPORT_NS() statement close to other module
+metadata definitions like MODULE_AUTHOR() or MODULE_LICENSE(). Refer to section
+5. for a way to create missing import statements automatically.
+
+4. Loading Modules that use namespaced Symbols
+==============================================
+
+At module loading time (e.g. `insmod`), the kernel will check each symbol
+referenced from the module for its availability and whether the namespace it
+might be exported to has been imported by the module. The default behaviour of
+the kernel is to reject loading modules that don't specify sufficient imports.
+An error will be logged and loading will be failed with EINVAL. In order to
+allow loading of modules that don't satisfy this precondition, a configuration
+option is available: Setting MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS=y will
+enable loading regardless, but will emit a warning.
+
+5. Automatically creating MODULE_IMPORT_NS statements
+=====================================================
+
+Missing namespaces imports can easily be detected at build time. In fact,
+modpost will emit a warning if a module uses a symbol from a namespace
+without importing it.
+MODULE_IMPORT_NS() statements will usually be added at a definite location
+(along with other module meta data). To make the life of module authors (and
+subsystem maintainers) easier, a script and make target is available to fixup
+missing imports. Fixing missing imports can be done with::
+
+ $ make nsdeps
+
+A typical scenario for module authors would be::
+
+ - write code that depends on a symbol from a not imported namespace
+ - `make`
+ - notice the warning of modpost telling about a missing import
+ - run `make nsdeps` to add the import to the correct code location
+
+For subsystem maintainers introducing a namespace, the steps are very similar.
+Again, `make nsdeps` will eventually add the missing namespace imports for
+in-tree modules::
+
+ - move or add symbols to a namespace (e.g. with EXPORT_SYMBOL_NS())
+ - `make` (preferably with an allmodconfig to cover all in-kernel
+ modules)
+ - notice the warning of modpost telling about a missing import
+ - run `make nsdeps` to add the import to the correct code location
+
diff --git a/Documentation/kernel-hacking/hacking.rst b/Documentation/kernel-hacking/hacking.rst
index 5891a701a159..a3ddb213a5e1 100644
--- a/Documentation/kernel-hacking/hacking.rst
+++ b/Documentation/kernel-hacking/hacking.rst
@@ -594,6 +594,24 @@ internal implementation issue, and not really an interface. Some
maintainers and developers may however require EXPORT_SYMBOL_GPL()
when adding any new APIs or functionality.
+:c:func:`EXPORT_SYMBOL_NS()`
+----------------------------
+
+Defined in ``include/linux/export.h``
+
+This is the variant of `EXPORT_SYMBOL()` that allows specifying a symbol
+namespace. Symbol Namespaces are documented in
+``Documentation/kbuild/namespaces.rst``.
+
+:c:func:`EXPORT_SYMBOL_NS_GPL()`
+--------------------------------
+
+Defined in ``include/linux/export.h``
+
+This is the variant of `EXPORT_SYMBOL_GPL()` that allows specifying a symbol
+namespace. Symbol Namespaces are documented in
+``Documentation/kbuild/namespaces.rst``.
+
Routines and Conventions
========================
--
2.23.0.187.g17f5b7556c-goog
Modules using symbols from the WATCHDOG_CORE namespace are required to
explicitly import the namespace. This patch was generated with the
following steps and serves as a reference to use the symbol namespace
feature:
1) Use EXPORT_SYMBOL_NS* macros instead of EXPORT_SYMBOL* for symbols
in watchdog_core.c
2) make (see warnings during modpost about missing imports)
3) make nsdeps
I used 'allmodconfig' for the above steps to ensure all occurrences are
patched.
Defining DEFAULT_SYMBOL_NAMESPACE in the Makefile is not trivial in this
case as not only watchdog_core is defined in drivers/watchdog/Makefile.
Hence this patch uses the variant of using the EXPORT_SYMBOL_NS* macros
to export into a different namespace.
An alternative to this patch would be a single definition line before
any use of EXPORT_SYMBOL*:
#define DEFAULT_SYMBOL_NAMESPACE WATCHDOG_CORE
This patch serves as a reference on how to use the symbol namespaces.
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Matthias Maennich <[email protected]>
---
drivers/hwmon/ftsteutates.c | 1 +
drivers/hwmon/sch56xx-common.c | 1 +
drivers/rtc/rtc-abx80x.c | 1 +
drivers/watchdog/armada_37xx_wdt.c | 1 +
drivers/watchdog/asm9260_wdt.c | 1 +
drivers/watchdog/aspeed_wdt.c | 1 +
drivers/watchdog/at91sam9_wdt.c | 1 +
drivers/watchdog/atlas7_wdt.c | 1 +
drivers/watchdog/bcm2835_wdt.c | 1 +
drivers/watchdog/bcm47xx_wdt.c | 1 +
drivers/watchdog/bcm7038_wdt.c | 1 +
drivers/watchdog/bcm_kona_wdt.c | 1 +
drivers/watchdog/bd70528_wdt.c | 1 +
drivers/watchdog/cadence_wdt.c | 1 +
drivers/watchdog/da9052_wdt.c | 1 +
drivers/watchdog/da9055_wdt.c | 1 +
drivers/watchdog/da9062_wdt.c | 1 +
drivers/watchdog/da9063_wdt.c | 1 +
drivers/watchdog/davinci_wdt.c | 1 +
drivers/watchdog/digicolor_wdt.c | 1 +
drivers/watchdog/dw_wdt.c | 1 +
drivers/watchdog/ebc-c384_wdt.c | 1 +
drivers/watchdog/ep93xx_wdt.c | 1 +
drivers/watchdog/ftwdt010_wdt.c | 1 +
drivers/watchdog/gpio_wdt.c | 1 +
drivers/watchdog/hpwdt.c | 1 +
drivers/watchdog/i6300esb.c | 1 +
drivers/watchdog/iTCO_wdt.c | 1 +
drivers/watchdog/ie6xx_wdt.c | 1 +
drivers/watchdog/imgpdc_wdt.c | 1 +
drivers/watchdog/imx2_wdt.c | 1 +
drivers/watchdog/intel-mid_wdt.c | 1 +
drivers/watchdog/it87_wdt.c | 1 +
drivers/watchdog/kempld_wdt.c | 1 +
drivers/watchdog/lpc18xx_wdt.c | 1 +
drivers/watchdog/max63xx_wdt.c | 1 +
drivers/watchdog/max77620_wdt.c | 1 +
drivers/watchdog/mei_wdt.c | 1 +
drivers/watchdog/mena21_wdt.c | 1 +
drivers/watchdog/menf21bmc_wdt.c | 1 +
drivers/watchdog/menz69_wdt.c | 1 +
drivers/watchdog/meson_gxbb_wdt.c | 1 +
drivers/watchdog/meson_wdt.c | 1 +
drivers/watchdog/mlx_wdt.c | 1 +
drivers/watchdog/moxart_wdt.c | 1 +
drivers/watchdog/mtk_wdt.c | 1 +
drivers/watchdog/ni903x_wdt.c | 1 +
drivers/watchdog/nic7018_wdt.c | 1 +
drivers/watchdog/npcm_wdt.c | 1 +
drivers/watchdog/of_xilinx_wdt.c | 1 +
drivers/watchdog/omap_wdt.c | 1 +
drivers/watchdog/pm8916_wdt.c | 1 +
drivers/watchdog/qcom-wdt.c | 1 +
drivers/watchdog/rave-sp-wdt.c | 1 +
drivers/watchdog/renesas_wdt.c | 1 +
drivers/watchdog/retu_wdt.c | 1 +
drivers/watchdog/rn5t618_wdt.c | 1 +
drivers/watchdog/rza_wdt.c | 1 +
drivers/watchdog/s3c2410_wdt.c | 1 +
drivers/watchdog/sama5d4_wdt.c | 1 +
drivers/watchdog/sirfsoc_wdt.c | 1 +
drivers/watchdog/softdog.c | 1 +
drivers/watchdog/sp5100_tco.c | 1 +
drivers/watchdog/sprd_wdt.c | 1 +
drivers/watchdog/st_lpc_wdt.c | 1 +
drivers/watchdog/stmp3xxx_rtc_wdt.c | 1 +
drivers/watchdog/stpmic1_wdt.c | 1 +
drivers/watchdog/sunxi_wdt.c | 1 +
drivers/watchdog/tangox_wdt.c | 1 +
drivers/watchdog/tegra_wdt.c | 1 +
drivers/watchdog/tqmx86_wdt.c | 1 +
drivers/watchdog/ts4800_wdt.c | 1 +
drivers/watchdog/ts72xx_wdt.c | 1 +
drivers/watchdog/twl4030_wdt.c | 1 +
drivers/watchdog/uniphier_wdt.c | 1 +
drivers/watchdog/via_wdt.c | 1 +
drivers/watchdog/w83627hf_wdt.c | 1 +
drivers/watchdog/watchdog_core.c | 10 +++++-----
drivers/watchdog/wdat_wdt.c | 1 +
drivers/watchdog/wm831x_wdt.c | 1 +
drivers/watchdog/wm8350_wdt.c | 1 +
drivers/watchdog/xen_wdt.c | 1 +
drivers/watchdog/ziirave_wdt.c | 1 +
83 files changed, 87 insertions(+), 5 deletions(-)
diff --git a/drivers/hwmon/ftsteutates.c b/drivers/hwmon/ftsteutates.c
index 371ce7745f5e..fa67f7c565be 100644
--- a/drivers/hwmon/ftsteutates.c
+++ b/drivers/hwmon/ftsteutates.c
@@ -830,3 +830,4 @@ module_i2c_driver(fts_driver);
MODULE_AUTHOR("Thilo Cestonaro <[email protected]>");
MODULE_DESCRIPTION("FTS Teutates driver");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/hwmon/sch56xx-common.c b/drivers/hwmon/sch56xx-common.c
index 6c84780e358e..06dd840f3bf7 100644
--- a/drivers/hwmon/sch56xx-common.c
+++ b/drivers/hwmon/sch56xx-common.c
@@ -571,6 +571,7 @@ static void __exit sch56xx_exit(void)
MODULE_DESCRIPTION("SMSC SCH56xx Hardware Monitoring Common Code");
MODULE_AUTHOR("Hans de Goede <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
module_init(sch56xx_init);
module_exit(sch56xx_exit);
diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c
index 73830670a41f..3ff3b96d14d7 100644
--- a/drivers/rtc/rtc-abx80x.c
+++ b/drivers/rtc/rtc-abx80x.c
@@ -880,3 +880,4 @@ MODULE_AUTHOR("Philippe De Muyter <[email protected]>");
MODULE_AUTHOR("Alexandre Belloni <[email protected]>");
MODULE_DESCRIPTION("Abracon ABX80X RTC driver");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/armada_37xx_wdt.c b/drivers/watchdog/armada_37xx_wdt.c
index e5dcb26d85f0..00e153ae70eb 100644
--- a/drivers/watchdog/armada_37xx_wdt.c
+++ b/drivers/watchdog/armada_37xx_wdt.c
@@ -370,4 +370,5 @@ MODULE_AUTHOR("Marek Behun <[email protected]>");
MODULE_DESCRIPTION("Armada 37xx CPU Watchdog");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("platform:armada_37xx_wdt");
diff --git a/drivers/watchdog/asm9260_wdt.c b/drivers/watchdog/asm9260_wdt.c
index 45047e514b8e..fd7289df2cb3 100644
--- a/drivers/watchdog/asm9260_wdt.c
+++ b/drivers/watchdog/asm9260_wdt.c
@@ -374,3 +374,4 @@ module_platform_driver(asm9260_wdt_driver);
MODULE_DESCRIPTION("asm9260 WatchDog Timer Driver");
MODULE_AUTHOR("Oleksij Rempel <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
index cc71861e033a..2607158965d6 100644
--- a/drivers/watchdog/aspeed_wdt.c
+++ b/drivers/watchdog/aspeed_wdt.c
@@ -334,3 +334,4 @@ module_exit(aspeed_wdt_exit);
MODULE_DESCRIPTION("Aspeed Watchdog Driver");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/at91sam9_wdt.c b/drivers/watchdog/at91sam9_wdt.c
index 292b5a1ca831..e7aa31fe4336 100644
--- a/drivers/watchdog/at91sam9_wdt.c
+++ b/drivers/watchdog/at91sam9_wdt.c
@@ -416,3 +416,4 @@ module_platform_driver_probe(at91wdt_driver, at91wdt_probe);
MODULE_AUTHOR("Renaud CERRATO <[email protected]>");
MODULE_DESCRIPTION("Watchdog driver for Atmel AT91SAM9x processors");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/atlas7_wdt.c b/drivers/watchdog/atlas7_wdt.c
index 9bfe650d802f..f67e6f101102 100644
--- a/drivers/watchdog/atlas7_wdt.c
+++ b/drivers/watchdog/atlas7_wdt.c
@@ -218,4 +218,5 @@ module_platform_driver(atlas7_wdt_driver);
MODULE_DESCRIPTION("CSRatlas7 watchdog driver");
MODULE_AUTHOR("Guo Zeng <[email protected]>");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("platform:atlas7-wdt");
diff --git a/drivers/watchdog/bcm2835_wdt.c b/drivers/watchdog/bcm2835_wdt.c
index dec6ca019bea..2f41b8a6e2f6 100644
--- a/drivers/watchdog/bcm2835_wdt.c
+++ b/drivers/watchdog/bcm2835_wdt.c
@@ -242,3 +242,4 @@ MODULE_ALIAS("platform:bcm2835-wdt");
MODULE_AUTHOR("Lubomir Rintel <[email protected]>");
MODULE_DESCRIPTION("Driver for Broadcom BCM2835 watchdog timer");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/bcm47xx_wdt.c b/drivers/watchdog/bcm47xx_wdt.c
index 05425c1dfd4c..231009f01024 100644
--- a/drivers/watchdog/bcm47xx_wdt.c
+++ b/drivers/watchdog/bcm47xx_wdt.c
@@ -241,3 +241,4 @@ MODULE_AUTHOR("Aleksandar Radovanovic");
MODULE_AUTHOR("Hauke Mehrtens <[email protected]>");
MODULE_DESCRIPTION("Watchdog driver for Broadcom BCM47xx");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/bcm7038_wdt.c b/drivers/watchdog/bcm7038_wdt.c
index 979caa18d3c8..e66184997775 100644
--- a/drivers/watchdog/bcm7038_wdt.c
+++ b/drivers/watchdog/bcm7038_wdt.c
@@ -212,5 +212,6 @@ module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_DESCRIPTION("Driver for Broadcom 7038 SoCs Watchdog");
MODULE_AUTHOR("Justin Chen");
diff --git a/drivers/watchdog/bcm_kona_wdt.c b/drivers/watchdog/bcm_kona_wdt.c
index eb850a8d19df..5b5a6a76c1aa 100644
--- a/drivers/watchdog/bcm_kona_wdt.c
+++ b/drivers/watchdog/bcm_kona_wdt.c
@@ -339,3 +339,4 @@ MODULE_ALIAS("platform:" BCM_KONA_WDT_NAME);
MODULE_AUTHOR("Markus Mayer <[email protected]>");
MODULE_DESCRIPTION("Broadcom Kona Watchdog Driver");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/bd70528_wdt.c b/drivers/watchdog/bd70528_wdt.c
index b0152fef4fc7..790748a3a30a 100644
--- a/drivers/watchdog/bd70528_wdt.c
+++ b/drivers/watchdog/bd70528_wdt.c
@@ -288,3 +288,4 @@ module_platform_driver(bd70528_wdt);
MODULE_AUTHOR("Matti Vaittinen <[email protected]>");
MODULE_DESCRIPTION("BD70528 watchdog driver");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/cadence_wdt.c b/drivers/watchdog/cadence_wdt.c
index f8d4e91d0383..a44f3140656e 100644
--- a/drivers/watchdog/cadence_wdt.c
+++ b/drivers/watchdog/cadence_wdt.c
@@ -438,3 +438,4 @@ module_platform_driver(cdns_wdt_driver);
MODULE_AUTHOR("Xilinx, Inc.");
MODULE_DESCRIPTION("Watchdog driver for Cadence WDT");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/da9052_wdt.c b/drivers/watchdog/da9052_wdt.c
index d708c091bf1b..a5ceea0503bb 100644
--- a/drivers/watchdog/da9052_wdt.c
+++ b/drivers/watchdog/da9052_wdt.c
@@ -191,4 +191,5 @@ module_platform_driver(da9052_wdt_driver);
MODULE_AUTHOR("Anthony Olech <[email protected]>");
MODULE_DESCRIPTION("DA9052 SM Device Driver");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("platform:da9052-watchdog");
diff --git a/drivers/watchdog/da9055_wdt.c b/drivers/watchdog/da9055_wdt.c
index 389a4bdd208c..05b075f2ea90 100644
--- a/drivers/watchdog/da9055_wdt.c
+++ b/drivers/watchdog/da9055_wdt.c
@@ -166,4 +166,5 @@ module_platform_driver(da9055_wdt_driver);
MODULE_AUTHOR("David Dajun Chen <[email protected]>");
MODULE_DESCRIPTION("DA9055 watchdog");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("platform:da9055-watchdog");
diff --git a/drivers/watchdog/da9062_wdt.c b/drivers/watchdog/da9062_wdt.c
index e149e66a6ea9..dfc2025d36ba 100644
--- a/drivers/watchdog/da9062_wdt.c
+++ b/drivers/watchdog/da9062_wdt.c
@@ -232,4 +232,5 @@ module_platform_driver(da9062_wdt_driver);
MODULE_AUTHOR("S Twiss <[email protected]>");
MODULE_DESCRIPTION("WDT device driver for Dialog DA9062 and DA9061");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("platform:da9062-watchdog");
diff --git a/drivers/watchdog/da9063_wdt.c b/drivers/watchdog/da9063_wdt.c
index 3d65e92a4e3f..ae0cb7011762 100644
--- a/drivers/watchdog/da9063_wdt.c
+++ b/drivers/watchdog/da9063_wdt.c
@@ -239,4 +239,5 @@ module_platform_driver(da9063_wdt_driver);
MODULE_AUTHOR("Mariusz Wojtasik <[email protected]>");
MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG);
diff --git a/drivers/watchdog/davinci_wdt.c b/drivers/watchdog/davinci_wdt.c
index 2b3f3cd382ef..4fa01dfa4edb 100644
--- a/drivers/watchdog/davinci_wdt.c
+++ b/drivers/watchdog/davinci_wdt.c
@@ -274,4 +274,5 @@ MODULE_PARM_DESC(heartbeat,
__MODULE_STRING(DEFAULT_HEARTBEAT));
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("platform:davinci-wdt");
diff --git a/drivers/watchdog/digicolor_wdt.c b/drivers/watchdog/digicolor_wdt.c
index 073d37867f47..ed86cf879dae 100644
--- a/drivers/watchdog/digicolor_wdt.c
+++ b/drivers/watchdog/digicolor_wdt.c
@@ -161,3 +161,4 @@ module_platform_driver(dc_wdt_driver);
MODULE_AUTHOR("Baruch Siach <[email protected]>");
MODULE_DESCRIPTION("Driver for Conexant Digicolor watchdog timer");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
index fef7c61f5555..e98ccb38eb1d 100644
--- a/drivers/watchdog/dw_wdt.c
+++ b/drivers/watchdog/dw_wdt.c
@@ -340,3 +340,4 @@ module_platform_driver(dw_wdt_driver);
MODULE_AUTHOR("Jamie Iles");
MODULE_DESCRIPTION("Synopsys DesignWare Watchdog Driver");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/ebc-c384_wdt.c b/drivers/watchdog/ebc-c384_wdt.c
index 8ef4b0df3855..7e4349472745 100644
--- a/drivers/watchdog/ebc-c384_wdt.c
+++ b/drivers/watchdog/ebc-c384_wdt.c
@@ -139,4 +139,5 @@ module_exit(ebc_c384_wdt_exit);
MODULE_AUTHOR("William Breathitt Gray <[email protected]>");
MODULE_DESCRIPTION("WinSystems EBC-C384 watchdog timer driver");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("isa:" MODULE_NAME);
diff --git a/drivers/watchdog/ep93xx_wdt.c b/drivers/watchdog/ep93xx_wdt.c
index 38e26f160b9a..edfa422896d7 100644
--- a/drivers/watchdog/ep93xx_wdt.c
+++ b/drivers/watchdog/ep93xx_wdt.c
@@ -144,3 +144,4 @@ MODULE_AUTHOR("Alessandro Zummo <[email protected]>");
MODULE_AUTHOR("H Hartley Sweeten <[email protected]>");
MODULE_DESCRIPTION("EP93xx Watchdog");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/ftwdt010_wdt.c b/drivers/watchdog/ftwdt010_wdt.c
index 21dcc7765688..c19186bc00b6 100644
--- a/drivers/watchdog/ftwdt010_wdt.c
+++ b/drivers/watchdog/ftwdt010_wdt.c
@@ -227,3 +227,4 @@ module_platform_driver(ftwdt010_wdt_driver);
MODULE_AUTHOR("Linus Walleij");
MODULE_DESCRIPTION("Watchdog driver for Faraday Technology FTWDT010");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/gpio_wdt.c b/drivers/watchdog/gpio_wdt.c
index 0923201ce874..6a90a7ecadeb 100644
--- a/drivers/watchdog/gpio_wdt.c
+++ b/drivers/watchdog/gpio_wdt.c
@@ -194,3 +194,4 @@ module_platform_driver(gpio_wdt_driver);
MODULE_AUTHOR("Alexander Shiyan <[email protected]>");
MODULE_DESCRIPTION("GPIO Watchdog");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/hpwdt.c b/drivers/watchdog/hpwdt.c
index 7d34bcf1c45b..fb4d228a0d7e 100644
--- a/drivers/watchdog/hpwdt.c
+++ b/drivers/watchdog/hpwdt.c
@@ -386,6 +386,7 @@ static struct pci_driver hpwdt_driver = {
MODULE_AUTHOR("Tom Mingarelli");
MODULE_DESCRIPTION("hpe watchdog driver");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_VERSION(HPWDT_VERSION);
module_param(soft_margin, int, 0);
diff --git a/drivers/watchdog/i6300esb.c b/drivers/watchdog/i6300esb.c
index a30835f547b3..700a8c6cae00 100644
--- a/drivers/watchdog/i6300esb.c
+++ b/drivers/watchdog/i6300esb.c
@@ -351,3 +351,4 @@ module_pci_driver(esb_driver);
MODULE_AUTHOR("Ross Biro and David Härdeman");
MODULE_DESCRIPTION("Watchdog driver for Intel 6300ESB chipsets");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
index c559f706ae7e..454d8ff3edc1 100644
--- a/drivers/watchdog/iTCO_wdt.c
+++ b/drivers/watchdog/iTCO_wdt.c
@@ -632,4 +632,5 @@ MODULE_AUTHOR("Wim Van Sebroeck <[email protected]>");
MODULE_DESCRIPTION("Intel TCO WatchDog Timer Driver");
MODULE_VERSION(DRV_VERSION);
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("platform:" DRV_NAME);
diff --git a/drivers/watchdog/ie6xx_wdt.c b/drivers/watchdog/ie6xx_wdt.c
index 8f28993fab8b..76bcff28eaf9 100644
--- a/drivers/watchdog/ie6xx_wdt.c
+++ b/drivers/watchdog/ie6xx_wdt.c
@@ -314,4 +314,5 @@ module_exit(ie6xx_wdt_exit);
MODULE_AUTHOR("Alexander Stein <[email protected]>");
MODULE_DESCRIPTION("Intel Atom E6xx Watchdog Device Driver");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("platform:" DRIVER_NAME);
diff --git a/drivers/watchdog/imgpdc_wdt.c b/drivers/watchdog/imgpdc_wdt.c
index b57ff3787052..6fe0fd7c0719 100644
--- a/drivers/watchdog/imgpdc_wdt.c
+++ b/drivers/watchdog/imgpdc_wdt.c
@@ -314,3 +314,4 @@ MODULE_AUTHOR("Jude Abraham <[email protected]>");
MODULE_AUTHOR("Naidu Tellapati <[email protected]>");
MODULE_DESCRIPTION("Imagination Technologies PDC Watchdog Timer Driver");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c
index 32af3974e6bb..dc6d4132ec1f 100644
--- a/drivers/watchdog/imx2_wdt.c
+++ b/drivers/watchdog/imx2_wdt.c
@@ -433,4 +433,5 @@ module_platform_driver_probe(imx2_wdt_driver, imx2_wdt_probe);
MODULE_AUTHOR("Wolfram Sang");
MODULE_DESCRIPTION("Watchdog driver for IMX2 and later");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("platform:" DRIVER_NAME);
diff --git a/drivers/watchdog/intel-mid_wdt.c b/drivers/watchdog/intel-mid_wdt.c
index 2cdbd37c700c..b859fd6d263b 100644
--- a/drivers/watchdog/intel-mid_wdt.c
+++ b/drivers/watchdog/intel-mid_wdt.c
@@ -181,3 +181,4 @@ module_platform_driver(mid_wdt_driver);
MODULE_AUTHOR("David Cohen <[email protected]>");
MODULE_DESCRIPTION("Watchdog Driver for Intel MID platform");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/it87_wdt.c b/drivers/watchdog/it87_wdt.c
index a4b71ebc8cab..610f5cdebf72 100644
--- a/drivers/watchdog/it87_wdt.c
+++ b/drivers/watchdog/it87_wdt.c
@@ -354,3 +354,4 @@ module_exit(it87_wdt_exit);
MODULE_AUTHOR("Oliver Schuster");
MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/kempld_wdt.c b/drivers/watchdog/kempld_wdt.c
index 40bd518ed873..20a40e221dbb 100644
--- a/drivers/watchdog/kempld_wdt.c
+++ b/drivers/watchdog/kempld_wdt.c
@@ -550,3 +550,4 @@ module_platform_driver(kempld_wdt_driver);
MODULE_DESCRIPTION("KEM PLD Watchdog Driver");
MODULE_AUTHOR("Michael Brunner <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/lpc18xx_wdt.c b/drivers/watchdog/lpc18xx_wdt.c
index 78cf11c94941..4e34a4bd0b24 100644
--- a/drivers/watchdog/lpc18xx_wdt.c
+++ b/drivers/watchdog/lpc18xx_wdt.c
@@ -316,3 +316,4 @@ module_platform_driver(lpc18xx_wdt_driver);
MODULE_AUTHOR("Ariel D'Alessandro <[email protected]>");
MODULE_DESCRIPTION("NXP LPC18xx Watchdog Timer Driver");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/max63xx_wdt.c b/drivers/watchdog/max63xx_wdt.c
index 3a899628a834..053c9285adac 100644
--- a/drivers/watchdog/max63xx_wdt.c
+++ b/drivers/watchdog/max63xx_wdt.c
@@ -284,3 +284,4 @@ MODULE_PARM_DESC(nodelay,
"(max6373/74 only, default=0)");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/max77620_wdt.c b/drivers/watchdog/max77620_wdt.c
index be6a53c30002..304817d379a7 100644
--- a/drivers/watchdog/max77620_wdt.c
+++ b/drivers/watchdog/max77620_wdt.c
@@ -209,3 +209,4 @@ MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
MODULE_AUTHOR("Laxman Dewangan <[email protected]>");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/mei_wdt.c b/drivers/watchdog/mei_wdt.c
index 5391bf3e6b11..5e03226cada1 100644
--- a/drivers/watchdog/mei_wdt.c
+++ b/drivers/watchdog/mei_wdt.c
@@ -662,4 +662,5 @@ module_mei_cl_driver(mei_wdt_driver);
MODULE_AUTHOR("Intel Corporation");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_DESCRIPTION("Device driver for Intel MEI iAMT watchdog");
diff --git a/drivers/watchdog/mena21_wdt.c b/drivers/watchdog/mena21_wdt.c
index 99d2359d5a8a..b759c66f1446 100644
--- a/drivers/watchdog/mena21_wdt.c
+++ b/drivers/watchdog/mena21_wdt.c
@@ -225,4 +225,5 @@ module_platform_driver(a21_wdt_driver);
MODULE_AUTHOR("MEN Mikro Elektronik");
MODULE_DESCRIPTION("MEN A21 Watchdog");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("platform:a21-watchdog");
diff --git a/drivers/watchdog/menf21bmc_wdt.c b/drivers/watchdog/menf21bmc_wdt.c
index 81ebdfc371f4..358881618e2f 100644
--- a/drivers/watchdog/menf21bmc_wdt.c
+++ b/drivers/watchdog/menf21bmc_wdt.c
@@ -181,4 +181,5 @@ module_platform_driver(menf21bmc_wdt);
MODULE_DESCRIPTION("MEN 14F021P00 BMC Watchdog driver");
MODULE_AUTHOR("Andreas Werner <[email protected]>");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("platform:menf21bmc_wdt");
diff --git a/drivers/watchdog/menz69_wdt.c b/drivers/watchdog/menz69_wdt.c
index ed18238c5407..d13fcfc0f59c 100644
--- a/drivers/watchdog/menz69_wdt.c
+++ b/drivers/watchdog/menz69_wdt.c
@@ -167,4 +167,5 @@ module_mcb_driver(men_z069_driver);
MODULE_AUTHOR("Johannes Thumshirn <[email protected]>");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("mcb:16z069");
diff --git a/drivers/watchdog/meson_gxbb_wdt.c b/drivers/watchdog/meson_gxbb_wdt.c
index d17c1a6ed723..f30f85380679 100644
--- a/drivers/watchdog/meson_gxbb_wdt.c
+++ b/drivers/watchdog/meson_gxbb_wdt.c
@@ -204,3 +204,4 @@ module_platform_driver(meson_gxbb_wdt_driver);
MODULE_AUTHOR("Neil Armstrong <[email protected]>");
MODULE_DESCRIPTION("Amlogic Meson GXBB Watchdog timer driver");
MODULE_LICENSE("Dual BSD/GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/meson_wdt.c b/drivers/watchdog/meson_wdt.c
index 459f3ae02c91..0d60bb5aa688 100644
--- a/drivers/watchdog/meson_wdt.c
+++ b/drivers/watchdog/meson_wdt.c
@@ -228,5 +228,6 @@ MODULE_PARM_DESC(nowayout,
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_AUTHOR("Carlo Caione <[email protected]>");
MODULE_DESCRIPTION("Meson Watchdog Timer Driver");
diff --git a/drivers/watchdog/mlx_wdt.c b/drivers/watchdog/mlx_wdt.c
index 03b9ac4b99af..2df48a6ed04b 100644
--- a/drivers/watchdog/mlx_wdt.c
+++ b/drivers/watchdog/mlx_wdt.c
@@ -287,4 +287,5 @@ module_platform_driver(mlxreg_wdt_driver);
MODULE_AUTHOR("Michael Shych <[email protected]>");
MODULE_DESCRIPTION("Mellanox watchdog driver");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("platform:mlx-wdt");
diff --git a/drivers/watchdog/moxart_wdt.c b/drivers/watchdog/moxart_wdt.c
index 6340a1f5f471..02dbfe2accfa 100644
--- a/drivers/watchdog/moxart_wdt.c
+++ b/drivers/watchdog/moxart_wdt.c
@@ -164,4 +164,5 @@ MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds");
MODULE_DESCRIPTION("MOXART watchdog driver");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_AUTHOR("Jonas Jensen <[email protected]>");
diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
index 9c3d0033260d..074c04324738 100644
--- a/drivers/watchdog/mtk_wdt.c
+++ b/drivers/watchdog/mtk_wdt.c
@@ -247,6 +247,7 @@ MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_AUTHOR("Matthias Brugger <[email protected]>");
MODULE_DESCRIPTION("Mediatek WatchDog Timer Driver");
MODULE_VERSION(DRV_VERSION);
diff --git a/drivers/watchdog/ni903x_wdt.c b/drivers/watchdog/ni903x_wdt.c
index 4cebad324b20..724d47f2f325 100644
--- a/drivers/watchdog/ni903x_wdt.c
+++ b/drivers/watchdog/ni903x_wdt.c
@@ -255,3 +255,4 @@ MODULE_DESCRIPTION("NI 903x Watchdog");
MODULE_AUTHOR("Jeff Westfahl <[email protected]>");
MODULE_AUTHOR("Kyle Roeschley <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/nic7018_wdt.c b/drivers/watchdog/nic7018_wdt.c
index 2a46cc662943..efe0f188c79a 100644
--- a/drivers/watchdog/nic7018_wdt.c
+++ b/drivers/watchdog/nic7018_wdt.c
@@ -250,3 +250,4 @@ module_platform_driver(watchdog_driver);
MODULE_DESCRIPTION("National Instruments NIC7018 Watchdog driver");
MODULE_AUTHOR("Hui Chun Ong <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/npcm_wdt.c b/drivers/watchdog/npcm_wdt.c
index 9c773c3d6d5d..aa2022a44985 100644
--- a/drivers/watchdog/npcm_wdt.c
+++ b/drivers/watchdog/npcm_wdt.c
@@ -248,3 +248,4 @@ module_platform_driver(npcm_wdt_driver);
MODULE_AUTHOR("Joel Stanley");
MODULE_DESCRIPTION("Watchdog driver for NPCM");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/of_xilinx_wdt.c b/drivers/watchdog/of_xilinx_wdt.c
index 7fe4f7c3f7ce..8d93e2089c6d 100644
--- a/drivers/watchdog/of_xilinx_wdt.c
+++ b/drivers/watchdog/of_xilinx_wdt.c
@@ -308,3 +308,4 @@ module_platform_driver(xwdt_driver);
MODULE_AUTHOR("Alejandro Cabrera <[email protected]>");
MODULE_DESCRIPTION("Xilinx Watchdog driver");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/omap_wdt.c b/drivers/watchdog/omap_wdt.c
index 9b91882fe3c4..49565608924a 100644
--- a/drivers/watchdog/omap_wdt.c
+++ b/drivers/watchdog/omap_wdt.c
@@ -375,4 +375,5 @@ module_platform_driver(omap_wdt_driver);
MODULE_AUTHOR("George G. Davis");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("platform:omap_wdt");
diff --git a/drivers/watchdog/pm8916_wdt.c b/drivers/watchdog/pm8916_wdt.c
index 2d3652004e39..f13c1c2bec07 100644
--- a/drivers/watchdog/pm8916_wdt.c
+++ b/drivers/watchdog/pm8916_wdt.c
@@ -210,3 +210,4 @@ module_platform_driver(pm8916_wdt_driver);
MODULE_AUTHOR("Loic Poulain <[email protected]>");
MODULE_DESCRIPTION("Qualcomm pm8916 watchdog driver");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c
index 7be7f87be28f..1ae02d3b5cb2 100644
--- a/drivers/watchdog/qcom-wdt.c
+++ b/drivers/watchdog/qcom-wdt.c
@@ -272,3 +272,4 @@ module_platform_driver(qcom_watchdog_driver);
MODULE_DESCRIPTION("QCOM KPSS Watchdog Driver");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/rave-sp-wdt.c b/drivers/watchdog/rave-sp-wdt.c
index 2c95615b6354..7fac3fabfcfb 100644
--- a/drivers/watchdog/rave-sp-wdt.c
+++ b/drivers/watchdog/rave-sp-wdt.c
@@ -329,6 +329,7 @@ module_platform_driver(rave_sp_wdt_driver);
MODULE_DEVICE_TABLE(of, rave_sp_wdt_of_match);
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_AUTHOR("Andrey Vostrikov <[email protected]>");
MODULE_AUTHOR("Nikita Yushchenko <[email protected]>");
MODULE_AUTHOR("Andrey Smirnov <[email protected]>");
diff --git a/drivers/watchdog/renesas_wdt.c b/drivers/watchdog/renesas_wdt.c
index 00662a8e039c..ec5b1ec6c292 100644
--- a/drivers/watchdog/renesas_wdt.c
+++ b/drivers/watchdog/renesas_wdt.c
@@ -315,4 +315,5 @@ module_platform_driver(rwdt_driver);
MODULE_DESCRIPTION("Renesas WDT Watchdog Driver");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_AUTHOR("Wolfram Sang <[email protected]>");
diff --git a/drivers/watchdog/retu_wdt.c b/drivers/watchdog/retu_wdt.c
index 258dfcf9cbda..6a3e2b8e5226 100644
--- a/drivers/watchdog/retu_wdt.c
+++ b/drivers/watchdog/retu_wdt.c
@@ -168,3 +168,4 @@ MODULE_DESCRIPTION("Retu watchdog");
MODULE_AUTHOR("Amit Kucheria");
MODULE_AUTHOR("Aaro Koskinen <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/rn5t618_wdt.c b/drivers/watchdog/rn5t618_wdt.c
index 234876047431..8f7bc6b1cb64 100644
--- a/drivers/watchdog/rn5t618_wdt.c
+++ b/drivers/watchdog/rn5t618_wdt.c
@@ -191,3 +191,4 @@ module_platform_driver(rn5t618_wdt_driver);
MODULE_AUTHOR("Beniamino Galvani <[email protected]>");
MODULE_DESCRIPTION("RN5T618 watchdog driver");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/rza_wdt.c b/drivers/watchdog/rza_wdt.c
index 7b6c365f7cd3..31ff9acc9af2 100644
--- a/drivers/watchdog/rza_wdt.c
+++ b/drivers/watchdog/rza_wdt.c
@@ -245,3 +245,4 @@ module_platform_driver(rza_wdt_driver);
MODULE_DESCRIPTION("Renesas RZ/A WDT Driver");
MODULE_AUTHOR("Chris Brandt <[email protected]>");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
index 2395f353e52d..5c1800d41411 100644
--- a/drivers/watchdog/s3c2410_wdt.c
+++ b/drivers/watchdog/s3c2410_wdt.c
@@ -739,3 +739,4 @@ module_platform_driver(s3c2410wdt_driver);
MODULE_AUTHOR("Ben Dooks <[email protected]>, Dimitry Andric <[email protected]>");
MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/sama5d4_wdt.c b/drivers/watchdog/sama5d4_wdt.c
index d193a60430b2..725f68703f1e 100644
--- a/drivers/watchdog/sama5d4_wdt.c
+++ b/drivers/watchdog/sama5d4_wdt.c
@@ -321,3 +321,4 @@ module_platform_driver(sama5d4_wdt_driver);
MODULE_AUTHOR("Atmel Corporation");
MODULE_DESCRIPTION("Atmel SAMA5D4 Watchdog Timer driver");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/sirfsoc_wdt.c b/drivers/watchdog/sirfsoc_wdt.c
index 734cf2966ecb..bcb75d9978f0 100644
--- a/drivers/watchdog/sirfsoc_wdt.c
+++ b/drivers/watchdog/sirfsoc_wdt.c
@@ -213,4 +213,5 @@ module_platform_driver(sirfsoc_wdt_driver);
MODULE_DESCRIPTION("SiRF SoC watchdog driver");
MODULE_AUTHOR("Xianglong Du <[email protected]>");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("platform:sirfsoc-wdt");
diff --git a/drivers/watchdog/softdog.c b/drivers/watchdog/softdog.c
index 3e4885c1545e..8d50543f7340 100644
--- a/drivers/watchdog/softdog.c
+++ b/drivers/watchdog/softdog.c
@@ -165,3 +165,4 @@ module_exit(softdog_exit);
MODULE_AUTHOR("Alan Cox");
MODULE_DESCRIPTION("Software Watchdog Device Driver");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c
index 93bd302ae7c5..716b9c43baf1 100644
--- a/drivers/watchdog/sp5100_tco.c
+++ b/drivers/watchdog/sp5100_tco.c
@@ -486,3 +486,4 @@ module_exit(sp5100_tco_exit);
MODULE_AUTHOR("Priyanka Gupta");
MODULE_DESCRIPTION("TCO timer driver for SP5100/SB800 chipset");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/sprd_wdt.c b/drivers/watchdog/sprd_wdt.c
index edba4e278685..55e883e8dcf4 100644
--- a/drivers/watchdog/sprd_wdt.c
+++ b/drivers/watchdog/sprd_wdt.c
@@ -384,3 +384,4 @@ module_platform_driver(sprd_watchdog_driver);
MODULE_AUTHOR("Eric Long <[email protected]>");
MODULE_DESCRIPTION("Spreadtrum Watchdog Timer Controller Driver");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/st_lpc_wdt.c b/drivers/watchdog/st_lpc_wdt.c
index 14ab6559c748..4a7e6b4694fa 100644
--- a/drivers/watchdog/st_lpc_wdt.c
+++ b/drivers/watchdog/st_lpc_wdt.c
@@ -305,3 +305,4 @@ module_platform_driver(st_wdog_driver);
MODULE_AUTHOR("David Paris <[email protected]>");
MODULE_DESCRIPTION("ST LPC Watchdog Driver");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/stmp3xxx_rtc_wdt.c b/drivers/watchdog/stmp3xxx_rtc_wdt.c
index 7caf3aa71c6a..f1dd033c2b4b 100644
--- a/drivers/watchdog/stmp3xxx_rtc_wdt.c
+++ b/drivers/watchdog/stmp3xxx_rtc_wdt.c
@@ -150,4 +150,5 @@ module_platform_driver(stmp3xxx_wdt_driver);
MODULE_DESCRIPTION("STMP3XXX RTC Watchdog Driver");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_AUTHOR("Wolfram Sang <[email protected]>");
diff --git a/drivers/watchdog/stpmic1_wdt.c b/drivers/watchdog/stpmic1_wdt.c
index 45d0c543466f..6cdbe4bf5aaa 100644
--- a/drivers/watchdog/stpmic1_wdt.c
+++ b/drivers/watchdog/stpmic1_wdt.c
@@ -138,3 +138,4 @@ module_platform_driver(stpmic1_wdt_driver);
MODULE_DESCRIPTION("Watchdog driver for STPMIC1 device");
MODULE_AUTHOR("Pascal Paillet <[email protected]>");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/sunxi_wdt.c b/drivers/watchdog/sunxi_wdt.c
index 5f05a45ac187..dea10c79b817 100644
--- a/drivers/watchdog/sunxi_wdt.c
+++ b/drivers/watchdog/sunxi_wdt.c
@@ -289,6 +289,7 @@ MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_AUTHOR("Carlo Caione <[email protected]>");
MODULE_AUTHOR("Henrik Nordstrom <[email protected]>");
MODULE_DESCRIPTION("sunxi WatchDog Timer Driver");
diff --git a/drivers/watchdog/tangox_wdt.c b/drivers/watchdog/tangox_wdt.c
index 1afb0e9d808c..bc9025d31977 100644
--- a/drivers/watchdog/tangox_wdt.c
+++ b/drivers/watchdog/tangox_wdt.c
@@ -207,3 +207,4 @@ module_platform_driver(tangox_wdt_driver);
MODULE_AUTHOR("Mans Rullgard <[email protected]>");
MODULE_DESCRIPTION("SMP86xx/SMP87xx Watchdog driver");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/tegra_wdt.c b/drivers/watchdog/tegra_wdt.c
index dfe06e506cad..06acd8251928 100644
--- a/drivers/watchdog/tegra_wdt.c
+++ b/drivers/watchdog/tegra_wdt.c
@@ -276,3 +276,4 @@ module_platform_driver(tegra_wdt_driver);
MODULE_AUTHOR("NVIDIA Corporation");
MODULE_DESCRIPTION("Tegra Watchdog Driver");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/tqmx86_wdt.c b/drivers/watchdog/tqmx86_wdt.c
index 72d0b0adde38..35b8bfffa34d 100644
--- a/drivers/watchdog/tqmx86_wdt.c
+++ b/drivers/watchdog/tqmx86_wdt.c
@@ -124,3 +124,4 @@ MODULE_AUTHOR("Andrew Lunn <[email protected]>");
MODULE_DESCRIPTION("TQMx86 Watchdog");
MODULE_ALIAS("platform:tqmx86-wdt");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/ts4800_wdt.c b/drivers/watchdog/ts4800_wdt.c
index c137ad2bd5c3..b07f75f9049b 100644
--- a/drivers/watchdog/ts4800_wdt.c
+++ b/drivers/watchdog/ts4800_wdt.c
@@ -200,4 +200,5 @@ module_platform_driver(ts4800_wdt_driver);
MODULE_AUTHOR("Damien Riegel <[email protected]>");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("platform:ts4800_wdt");
diff --git a/drivers/watchdog/ts72xx_wdt.c b/drivers/watchdog/ts72xx_wdt.c
index bf918f5fa131..efd74cfabbf8 100644
--- a/drivers/watchdog/ts72xx_wdt.c
+++ b/drivers/watchdog/ts72xx_wdt.c
@@ -174,4 +174,5 @@ module_platform_driver(ts72xx_wdt_driver);
MODULE_AUTHOR("Mika Westerberg <[email protected]>");
MODULE_DESCRIPTION("TS-72xx SBC Watchdog");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("platform:ts72xx-wdt");
diff --git a/drivers/watchdog/twl4030_wdt.c b/drivers/watchdog/twl4030_wdt.c
index 355e428c0b99..98bcebe3a0b7 100644
--- a/drivers/watchdog/twl4030_wdt.c
+++ b/drivers/watchdog/twl4030_wdt.c
@@ -123,5 +123,6 @@ module_platform_driver(twl4030_wdt_driver);
MODULE_AUTHOR("Nokia Corporation");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("platform:twl4030_wdt");
diff --git a/drivers/watchdog/uniphier_wdt.c b/drivers/watchdog/uniphier_wdt.c
index 8e9242c23022..3a6d2d3a8f3c 100644
--- a/drivers/watchdog/uniphier_wdt.c
+++ b/drivers/watchdog/uniphier_wdt.c
@@ -255,3 +255,4 @@ MODULE_PARM_DESC(nowayout,
MODULE_AUTHOR("Keiji Hayashibara <[email protected]>");
MODULE_DESCRIPTION("UniPhier Watchdog Device Driver");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/via_wdt.c b/drivers/watchdog/via_wdt.c
index eeb39f96e72e..899a4fe1d7b6 100644
--- a/drivers/watchdog/via_wdt.c
+++ b/drivers/watchdog/via_wdt.c
@@ -259,3 +259,4 @@ module_pci_driver(wdt_driver);
MODULE_AUTHOR("Marc Vertes");
MODULE_DESCRIPTION("Driver for watchdog timer on VIA chipset");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/w83627hf_wdt.c b/drivers/watchdog/w83627hf_wdt.c
index 38b31e9947aa..b66aea20a96e 100644
--- a/drivers/watchdog/w83627hf_wdt.c
+++ b/drivers/watchdog/w83627hf_wdt.c
@@ -528,5 +528,6 @@ module_init(wdt_init);
module_exit(wdt_exit);
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_AUTHOR("Pádraig Brady <[email protected]>");
MODULE_DESCRIPTION("w83627hf/thf WDT driver");
diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
index 21e8085b848b..9deb22af5daa 100644
--- a/drivers/watchdog/watchdog_core.c
+++ b/drivers/watchdog/watchdog_core.c
@@ -145,7 +145,7 @@ int watchdog_init_timeout(struct watchdog_device *wdd,
return ret;
}
-EXPORT_SYMBOL_GPL(watchdog_init_timeout);
+EXPORT_SYMBOL_NS_GPL(watchdog_init_timeout, WATCHDOG_CORE);
static int watchdog_restart_notifier(struct notifier_block *nb,
unsigned long action, void *data)
@@ -180,7 +180,7 @@ void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority)
{
wdd->restart_nb.priority = priority;
}
-EXPORT_SYMBOL_GPL(watchdog_set_restart_priority);
+EXPORT_SYMBOL_NS_GPL(watchdog_set_restart_priority, WATCHDOG_CORE);
static int __watchdog_register_device(struct watchdog_device *wdd)
{
@@ -279,7 +279,7 @@ int watchdog_register_device(struct watchdog_device *wdd)
return ret;
}
-EXPORT_SYMBOL_GPL(watchdog_register_device);
+EXPORT_SYMBOL_NS_GPL(watchdog_register_device, WATCHDOG_CORE);
static void __watchdog_unregister_device(struct watchdog_device *wdd)
{
@@ -311,7 +311,7 @@ void watchdog_unregister_device(struct watchdog_device *wdd)
mutex_unlock(&wtd_deferred_reg_mutex);
}
-EXPORT_SYMBOL_GPL(watchdog_unregister_device);
+EXPORT_SYMBOL_NS_GPL(watchdog_unregister_device, WATCHDOG_CORE);
static void devm_watchdog_unregister_device(struct device *dev, void *res)
{
@@ -348,7 +348,7 @@ int devm_watchdog_register_device(struct device *dev,
return ret;
}
-EXPORT_SYMBOL_GPL(devm_watchdog_register_device);
+EXPORT_SYMBOL_NS_GPL(devm_watchdog_register_device, WATCHDOG_CORE);
static int __init watchdog_deferred_registration(void)
{
diff --git a/drivers/watchdog/wdat_wdt.c b/drivers/watchdog/wdat_wdt.c
index e7cf41aa26c3..027339a557ce 100644
--- a/drivers/watchdog/wdat_wdt.c
+++ b/drivers/watchdog/wdat_wdt.c
@@ -523,4 +523,5 @@ module_platform_driver(wdat_wdt_driver);
MODULE_AUTHOR("Mika Westerberg <[email protected]>");
MODULE_DESCRIPTION("ACPI Hardware Watchdog (WDAT) driver");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("platform:wdat_wdt");
diff --git a/drivers/watchdog/wm831x_wdt.c b/drivers/watchdog/wm831x_wdt.c
index 030ce240620d..a17e2ac251a1 100644
--- a/drivers/watchdog/wm831x_wdt.c
+++ b/drivers/watchdog/wm831x_wdt.c
@@ -282,4 +282,5 @@ module_platform_driver(wm831x_wdt_driver);
MODULE_AUTHOR("Mark Brown");
MODULE_DESCRIPTION("WM831x Watchdog");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("platform:wm831x-watchdog");
diff --git a/drivers/watchdog/wm8350_wdt.c b/drivers/watchdog/wm8350_wdt.c
index 33c62d51f00a..f81e661662e6 100644
--- a/drivers/watchdog/wm8350_wdt.c
+++ b/drivers/watchdog/wm8350_wdt.c
@@ -175,4 +175,5 @@ module_platform_driver(wm8350_wdt_driver);
MODULE_AUTHOR("Mark Brown");
MODULE_DESCRIPTION("WM8350 Watchdog");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
MODULE_ALIAS("platform:wm8350-wdt");
diff --git a/drivers/watchdog/xen_wdt.c b/drivers/watchdog/xen_wdt.c
index b343f421dc72..8b21a4b51047 100644
--- a/drivers/watchdog/xen_wdt.c
+++ b/drivers/watchdog/xen_wdt.c
@@ -206,3 +206,4 @@ module_exit(xen_wdt_cleanup_module);
MODULE_AUTHOR("Jan Beulich <[email protected]>");
MODULE_DESCRIPTION("Xen WatchDog Timer Driver");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
diff --git a/drivers/watchdog/ziirave_wdt.c b/drivers/watchdog/ziirave_wdt.c
index dec660c509b3..2d81c7b546f2 100644
--- a/drivers/watchdog/ziirave_wdt.c
+++ b/drivers/watchdog/ziirave_wdt.c
@@ -751,3 +751,4 @@ module_i2c_driver(ziirave_wdt_driver);
MODULE_AUTHOR("Martyn Welch <[email protected]");
MODULE_DESCRIPTION("Zodiac Aerospace RAVE Switch Watchdog Processor Driver");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(WATCHDOG_CORE);
--
2.23.0.187.g17f5b7556c-goog
This change allows growing struct kernel_symbol without wasting bytes to
alignment. It also concretized the alignment of ksymtab entries if
relative references are used for ksymtab entries.
struct kernel_symbol was already implicitly being aligned to the word
size, except on x86_64 and m68k, where it is aligned to 16 and 2 bytes,
respectively.
As far as I can tell there is no requirement for aligning struct
kernel_symbol to 16 bytes on x86_64, but gcc aligns structs to their
size, and the linker aligns the custom __ksymtab sections to the largest
data type contained within, so setting KSYM_ALIGN to 16 was necessary to
stay consistent with the code generated for non-ASM EXPORT_SYMBOL(). Now
that non-ASM EXPORT_SYMBOL() explicitly aligns to word size (8),
KSYM_ALIGN is no longer necessary.
In case of relative references, the alignment has been changed
accordingly to not waste space when adding new struct members.
As for m68k, struct kernel_symbol is aligned to 2 bytes even though the
structure itself is 8 bytes; using a 4-byte alignment shouldn't hurt.
I manually verified the output of the __ksymtab sections didn't change
on x86, x86_64, arm, arm64 and m68k. As expected, the section contents
didn't change, and the ELF section alignment only changed on x86_64 and
m68k. Feedback from other archs more than welcome.
Co-developed-by: Martijn Coenen <[email protected]>
Signed-off-by: Martijn Coenen <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Matthias Maennich <[email protected]>
---
arch/m68k/include/asm/export.h | 1 -
include/asm-generic/export.h | 8 +++-----
include/linux/export.h | 3 ++-
3 files changed, 5 insertions(+), 7 deletions(-)
diff --git a/arch/m68k/include/asm/export.h b/arch/m68k/include/asm/export.h
index 0af20f48bd07..b53008b67ce1 100644
--- a/arch/m68k/include/asm/export.h
+++ b/arch/m68k/include/asm/export.h
@@ -1,3 +1,2 @@
-#define KSYM_ALIGN 2
#define KCRC_ALIGN 2
#include <asm-generic/export.h>
diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h
index 294d6ae785d4..63f54907317b 100644
--- a/include/asm-generic/export.h
+++ b/include/asm-generic/export.h
@@ -4,15 +4,13 @@
#ifndef KSYM_FUNC
#define KSYM_FUNC(x) x
#endif
-#ifdef CONFIG_64BIT
-#ifndef KSYM_ALIGN
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+#define KSYM_ALIGN 4
+#elif defined(CONFIG_64BIT)
#define KSYM_ALIGN 8
-#endif
#else
-#ifndef KSYM_ALIGN
#define KSYM_ALIGN 4
#endif
-#endif
#ifndef KCRC_ALIGN
#define KCRC_ALIGN 4
#endif
diff --git a/include/linux/export.h b/include/linux/export.h
index fd8711ed9ac4..28a4d2150689 100644
--- a/include/linux/export.h
+++ b/include/linux/export.h
@@ -52,7 +52,7 @@ extern struct module __this_module;
#define __KSYMTAB_ENTRY(sym, sec) \
__ADDRESSABLE(sym) \
asm(" .section \"___ksymtab" sec "+" #sym "\", \"a\" \n" \
- " .balign 8 \n" \
+ " .balign 4 \n" \
"__ksymtab_" #sym ": \n" \
" .long " #sym "- . \n" \
" .long __kstrtab_" #sym "- . \n" \
@@ -66,6 +66,7 @@ struct kernel_symbol {
#define __KSYMTAB_ENTRY(sym, sec) \
static const struct kernel_symbol __ksymtab_##sym \
__attribute__((section("___ksymtab" sec "+" #sym), used)) \
+ __aligned(sizeof(void *)) \
= { (unsigned long)&sym, __kstrtab_##sym }
struct kernel_symbol {
--
2.23.0.187.g17f5b7556c-goog
If MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS is enabled (default=n), the
requirement for modules to import all namespaces that are used by
the module is relaxed.
Enabling this option effectively allows (invalid) modules to be loaded
while only a warning is emitted.
Disabling this option keeps the enforcement at module loading time and
loading is denied if the module's imports are not satisfactory.
Reviewed-by: Martijn Coenen <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Matthias Maennich <[email protected]>
---
init/Kconfig | 13 +++++++++++++
kernel/module.c | 11 +++++++++--
2 files changed, 22 insertions(+), 2 deletions(-)
diff --git a/init/Kconfig b/init/Kconfig
index bd7d650d4a99..cc28561288a7 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -2119,6 +2119,19 @@ config MODULE_COMPRESS_XZ
endchoice
+config MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
+ bool "Allow loading of modules with missing namespace imports"
+ help
+ Symbols exported with EXPORT_SYMBOL_NS*() are considered exported in
+ a namespace. A module that makes use of a symbol exported with such a
+ namespace is required to import the namespace via MODULE_IMPORT_NS().
+ There is no technical reason to enforce correct namespace imports,
+ but it creates consistency between symbols defining namespaces and
+ users importing namespaces they make use of. This option relaxes this
+ requirement and lifts the enforcement when loading a module.
+
+ If unsure, say N.
+
config TRIM_UNUSED_KSYMS
bool "Trim unused exported kernel symbols"
depends on MODULES && !UNUSED_SYMBOLS
diff --git a/kernel/module.c b/kernel/module.c
index 6bb9b938f9c7..f76efcf2043e 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1408,9 +1408,16 @@ static int verify_namespace_is_imported(const struct load_info *info,
imported_namespace = get_next_modinfo(
info, "import_ns", imported_namespace);
}
- pr_err("%s: module uses symbol (%s) from namespace %s, but does not import it.\n",
- mod->name, kernel_symbol_name(sym), namespace);
+#ifdef CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
+ pr_warn(
+#else
+ pr_err(
+#endif
+ "%s: module uses symbol (%s) from namespace %s, but does not import it.\n",
+ mod->name, kernel_symbol_name(sym), namespace);
+#ifndef CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
return -EINVAL;
+#endif
}
return 0;
}
--
2.23.0.187.g17f5b7556c-goog
This patch adds an option to modpost to generate a <module>.ns_deps file
per module, containing the namespace dependencies for that module.
E.g. if the linked module my-module.ko would depend on the symbol
myfunc.MY_NS in the namespace MY_NS, the my-module.ns_deps file created
by modpost would contain the entry MY_NS to express the namespace
dependency of my-module imposed by using the symbol myfunc.
These files can subsequently be used by static analysis tools (like
coccinelle scripts) to address issues with missing namespace imports. A
later patch of this series will introduce such a script 'nsdeps' and a
corresponding make target to automatically add missing
MODULE_IMPORT_NS() definitions to the module's sources. For that it uses
the information provided in the generated .ns_deps files.
Co-developed-by: Martijn Coenen <[email protected]>
Signed-off-by: Martijn Coenen <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Matthias Maennich <[email protected]>
---
.gitignore | 1 +
Makefile | 2 +-
scripts/mod/modpost.c | 54 +++++++++++++++++++++++++++++++++++++++----
scripts/mod/modpost.h | 2 ++
4 files changed, 53 insertions(+), 6 deletions(-)
diff --git a/.gitignore b/.gitignore
index 2030c7a4d2f8..9ee63aa2a3fb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -32,6 +32,7 @@
*.lzo
*.mod
*.mod.c
+*.ns_deps
*.o
*.o.*
*.order
diff --git a/Makefile b/Makefile
index 0cbe8717bdb3..0cdb957ae2c3 100644
--- a/Makefile
+++ b/Makefile
@@ -1669,7 +1669,7 @@ clean: $(clean-dirs)
-o -name '*.ko.*' \
-o -name '*.dtb' -o -name '*.dtb.S' -o -name '*.dt.yaml' \
-o -name '*.dwo' -o -name '*.lst' \
- -o -name '*.su' -o -name '*.mod' \
+ -o -name '*.su' -o -name '*.mod' -o -name '*.ns_deps' \
-o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
-o -name '*.lex.c' -o -name '*.tab.[ch]' \
-o -name '*.asn1.[ch]' \
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index c2d49afaea1c..be72da25fe7c 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -38,6 +38,8 @@ static int sec_mismatch_count = 0;
static int sec_mismatch_fatal = 0;
/* ignore missing files */
static int ignore_missing_files;
+/* write namespace dependencies */
+static int write_namespace_deps;
enum export {
export_plain, export_unused, export_gpl,
@@ -2176,10 +2178,15 @@ static int check_exports(struct module *mod)
else
basename = mod->name;
- if (exp->namespace &&
- !module_imports_namespace(mod, exp->namespace)) {
- warn("module %s uses symbol %s from namespace %s, but does not import it.\n",
- basename, exp->name, exp->namespace);
+ if (exp->namespace) {
+ add_namespace(&mod->required_namespaces,
+ exp->namespace);
+
+ if (!write_namespace_deps &&
+ !module_imports_namespace(mod, exp->namespace)) {
+ warn("module %s uses symbol %s from namespace %s, but does not import it.\n",
+ basename, exp->name, exp->namespace);
+ }
}
if (!mod->gpl_compatible)
@@ -2484,6 +2491,31 @@ static void write_dump(const char *fname)
free(buf.p);
}
+static void write_namespace_deps_files(void)
+{
+ struct module *mod;
+ struct namespace_list *ns;
+ struct buffer ns_deps_buf = {};
+
+ for (mod = modules; mod; mod = mod->next) {
+ char fname[PATH_MAX];
+
+ if (mod->skip)
+ continue;
+
+ ns_deps_buf.pos = 0;
+
+ for (ns = mod->required_namespaces; ns; ns = ns->next)
+ buf_printf(&ns_deps_buf, "%s\n", ns->namespace);
+
+ if (ns_deps_buf.pos == 0)
+ continue;
+
+ sprintf(fname, "%s.ns_deps", mod->name);
+ write_if_changed(&ns_deps_buf, fname);
+ }
+}
+
struct ext_sym_list {
struct ext_sym_list *next;
const char *file;
@@ -2500,7 +2532,7 @@ int main(int argc, char **argv)
struct ext_sym_list *extsym_iter;
struct ext_sym_list *extsym_start = NULL;
- while ((opt = getopt(argc, argv, "i:I:e:mnsT:o:awE")) != -1) {
+ while ((opt = getopt(argc, argv, "i:I:e:mnsT:o:awEd")) != -1) {
switch (opt) {
case 'i':
kernel_read = optarg;
@@ -2541,6 +2573,9 @@ int main(int argc, char **argv)
case 'E':
sec_mismatch_fatal = 1;
break;
+ case 'd':
+ write_namespace_deps = 1;
+ break;
default:
exit(1);
}
@@ -2575,6 +2610,9 @@ int main(int argc, char **argv)
err |= check_modname_len(mod);
err |= check_exports(mod);
+ if (write_namespace_deps)
+ continue;
+
add_header(&buf, mod);
add_intree_flag(&buf, !external_module);
add_retpoline(&buf);
@@ -2587,6 +2625,12 @@ int main(int argc, char **argv)
sprintf(fname, "%s.mod.c", mod->name);
write_if_changed(&buf, fname);
}
+
+ if (write_namespace_deps) {
+ write_namespace_deps_files();
+ return 0;
+ }
+
if (dump_write)
write_dump(dump_write);
if (sec_mismatch_count && sec_mismatch_fatal)
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index 9626bf3e7424..92a926d375d2 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -126,6 +126,8 @@ struct module {
struct buffer dev_table_buf;
char srcversion[25];
int is_dot_o;
+ // Required namespace dependencies
+ struct namespace_list *required_namespaces;
// Actual imported namespaces
struct namespace_list *imported_namespaces;
};
--
2.23.0.187.g17f5b7556c-goog
Modules using these symbols are required to explicitly import the
namespace. This patch was generated with the following steps and serves
as a reference to use the symbol namespace feature:
1) Define DEFAULT_SYMBOL_NAMESPACE in the corresponding Makefile
2) make (see warnings during modpost about missing imports)
3) make nsdeps
Instead of a DEFAULT_SYMBOL_NAMESPACE definition, the EXPORT_SYMBOL_NS
variants can be used to explicitly specify the namespace. The advantage
of the method used here is that newly added symbols are automatically
exported and existing ones are exported without touching their
respective EXPORT_SYMBOL macro expansion.
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Matthias Maennich <[email protected]>
---
drivers/usb/storage/Makefile | 2 ++
drivers/usb/storage/alauda.c | 1 +
drivers/usb/storage/cypress_atacb.c | 1 +
drivers/usb/storage/datafab.c | 1 +
drivers/usb/storage/ene_ub6250.c | 1 +
drivers/usb/storage/freecom.c | 1 +
drivers/usb/storage/isd200.c | 1 +
drivers/usb/storage/jumpshot.c | 1 +
drivers/usb/storage/karma.c | 1 +
drivers/usb/storage/onetouch.c | 1 +
drivers/usb/storage/realtek_cr.c | 1 +
drivers/usb/storage/sddr09.c | 1 +
drivers/usb/storage/sddr55.c | 1 +
drivers/usb/storage/shuttle_usbat.c | 1 +
drivers/usb/storage/uas.c | 1 +
15 files changed, 16 insertions(+)
diff --git a/drivers/usb/storage/Makefile b/drivers/usb/storage/Makefile
index a67ddcbb4e24..46635fa4a340 100644
--- a/drivers/usb/storage/Makefile
+++ b/drivers/usb/storage/Makefile
@@ -8,6 +8,8 @@
ccflags-y := -I $(srctree)/drivers/scsi
+ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=USB_STORAGE
+
obj-$(CONFIG_USB_UAS) += uas.o
obj-$(CONFIG_USB_STORAGE) += usb-storage.o
diff --git a/drivers/usb/storage/alauda.c b/drivers/usb/storage/alauda.c
index 6b8edf6178df..ddab2cd3d2e7 100644
--- a/drivers/usb/storage/alauda.c
+++ b/drivers/usb/storage/alauda.c
@@ -36,6 +36,7 @@
MODULE_DESCRIPTION("Driver for Alauda-based card readers");
MODULE_AUTHOR("Daniel Drake <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
/*
* Status bytes
diff --git a/drivers/usb/storage/cypress_atacb.c b/drivers/usb/storage/cypress_atacb.c
index 4825902377eb..a6f3267bbef6 100644
--- a/drivers/usb/storage/cypress_atacb.c
+++ b/drivers/usb/storage/cypress_atacb.c
@@ -22,6 +22,7 @@
MODULE_DESCRIPTION("SAT support for Cypress USB/ATA bridges with ATACB");
MODULE_AUTHOR("Matthieu Castet <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
/*
* The table of devices
diff --git a/drivers/usb/storage/datafab.c b/drivers/usb/storage/datafab.c
index 09353be199be..588818483f4b 100644
--- a/drivers/usb/storage/datafab.c
+++ b/drivers/usb/storage/datafab.c
@@ -54,6 +54,7 @@
MODULE_DESCRIPTION("Driver for Datafab USB Compact Flash reader");
MODULE_AUTHOR("Jimmie Mayfield <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
struct datafab_info {
unsigned long sectors; /* total sector count */
diff --git a/drivers/usb/storage/ene_ub6250.c b/drivers/usb/storage/ene_ub6250.c
index c26129d5b943..8b1b73065421 100644
--- a/drivers/usb/storage/ene_ub6250.c
+++ b/drivers/usb/storage/ene_ub6250.c
@@ -26,6 +26,7 @@
MODULE_DESCRIPTION("Driver for ENE UB6250 reader");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
MODULE_FIRMWARE(SD_INIT1_FIRMWARE);
MODULE_FIRMWARE(SD_INIT2_FIRMWARE);
MODULE_FIRMWARE(SD_RW_FIRMWARE);
diff --git a/drivers/usb/storage/freecom.c b/drivers/usb/storage/freecom.c
index 4f542df37a44..34e7eaff1174 100644
--- a/drivers/usb/storage/freecom.c
+++ b/drivers/usb/storage/freecom.c
@@ -29,6 +29,7 @@
MODULE_DESCRIPTION("Driver for Freecom USB/IDE adaptor");
MODULE_AUTHOR("David Brown <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
#ifdef CONFIG_USB_STORAGE_DEBUG
static void pdump(struct us_data *us, void *ibuffer, int length);
diff --git a/drivers/usb/storage/isd200.c b/drivers/usb/storage/isd200.c
index 2b474d60b4db..c4da3fd6eff9 100644
--- a/drivers/usb/storage/isd200.c
+++ b/drivers/usb/storage/isd200.c
@@ -53,6 +53,7 @@
MODULE_DESCRIPTION("Driver for In-System Design, Inc. ISD200 ASIC");
MODULE_AUTHOR("Björn Stenberg <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
static int isd200_Initialization(struct us_data *us);
diff --git a/drivers/usb/storage/jumpshot.c b/drivers/usb/storage/jumpshot.c
index 917f170c4124..229bf0c1afc9 100644
--- a/drivers/usb/storage/jumpshot.c
+++ b/drivers/usb/storage/jumpshot.c
@@ -51,6 +51,7 @@
MODULE_DESCRIPTION("Driver for Lexar \"Jumpshot\" Compact Flash reader");
MODULE_AUTHOR("Jimmie Mayfield <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
/*
* The table of devices
diff --git a/drivers/usb/storage/karma.c b/drivers/usb/storage/karma.c
index 395cf8fb5870..05cec81dcd3f 100644
--- a/drivers/usb/storage/karma.c
+++ b/drivers/usb/storage/karma.c
@@ -23,6 +23,7 @@
MODULE_DESCRIPTION("Driver for Rio Karma");
MODULE_AUTHOR("Bob Copeland <[email protected]>, Keith Bennett <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
#define RIO_PREFIX "RIOP\x00"
#define RIO_PREFIX_LEN 5
diff --git a/drivers/usb/storage/onetouch.c b/drivers/usb/storage/onetouch.c
index 39a5009a41a6..a989fe930e21 100644
--- a/drivers/usb/storage/onetouch.c
+++ b/drivers/usb/storage/onetouch.c
@@ -25,6 +25,7 @@
MODULE_DESCRIPTION("Maxtor USB OneTouch hard drive button driver");
MODULE_AUTHOR("Nick Sillik <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
#define ONETOUCH_PKT_LEN 0x02
#define ONETOUCH_BUTTON KEY_PROG1
diff --git a/drivers/usb/storage/realtek_cr.c b/drivers/usb/storage/realtek_cr.c
index 1d9ce9cbc831..3789698d9d3c 100644
--- a/drivers/usb/storage/realtek_cr.c
+++ b/drivers/usb/storage/realtek_cr.c
@@ -35,6 +35,7 @@
MODULE_DESCRIPTION("Driver for Realtek USB Card Reader");
MODULE_AUTHOR("wwang <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
static int auto_delink_en = 1;
module_param(auto_delink_en, int, S_IRUGO | S_IWUSR);
diff --git a/drivers/usb/storage/sddr09.c b/drivers/usb/storage/sddr09.c
index bc9da736bdfc..51bcd4a43690 100644
--- a/drivers/usb/storage/sddr09.c
+++ b/drivers/usb/storage/sddr09.c
@@ -47,6 +47,7 @@
MODULE_DESCRIPTION("Driver for SanDisk SDDR-09 SmartMedia reader");
MODULE_AUTHOR("Andries Brouwer <[email protected]>, Robert Baruch <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
static int usb_stor_sddr09_dpcm_init(struct us_data *us);
static int sddr09_transport(struct scsi_cmnd *srb, struct us_data *us);
diff --git a/drivers/usb/storage/sddr55.c b/drivers/usb/storage/sddr55.c
index b8527c55335b..ba955d65eb0e 100644
--- a/drivers/usb/storage/sddr55.c
+++ b/drivers/usb/storage/sddr55.c
@@ -29,6 +29,7 @@
MODULE_DESCRIPTION("Driver for SanDisk SDDR-55 SmartMedia reader");
MODULE_AUTHOR("Simon Munton");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
/*
* The table of devices
diff --git a/drivers/usb/storage/shuttle_usbat.c b/drivers/usb/storage/shuttle_usbat.c
index 854498e1012c..54aa1392c9ca 100644
--- a/drivers/usb/storage/shuttle_usbat.c
+++ b/drivers/usb/storage/shuttle_usbat.c
@@ -48,6 +48,7 @@
MODULE_DESCRIPTION("Driver for SCM Microsystems (a.k.a. Shuttle) USB-ATAPI cable");
MODULE_AUTHOR("Daniel Drake <[email protected]>, Robert Baruch <[email protected]>");
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
/* Supported device types */
#define USBAT_DEV_HP8200 0x01
diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
index 047c5922618f..bf80d6f81f58 100644
--- a/drivers/usb/storage/uas.c
+++ b/drivers/usb/storage/uas.c
@@ -1219,5 +1219,6 @@ static struct usb_driver uas_driver = {
module_usb_driver(uas_driver);
MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(USB_STORAGE);
MODULE_AUTHOR(
"Hans de Goede <[email protected]>, Matthew Wilcox and Sarah Sharp");
--
2.23.0.187.g17f5b7556c-goog
On Tue, Sep 03, 2019 at 04:06:38PM +0100, Matthias Maennich wrote:
> Modules using symbols from the WATCHDOG_CORE namespace are required to
> explicitly import the namespace. This patch was generated with the
> following steps and serves as a reference to use the symbol namespace
> feature:
>
> 1) Use EXPORT_SYMBOL_NS* macros instead of EXPORT_SYMBOL* for symbols
> in watchdog_core.c
> 2) make (see warnings during modpost about missing imports)
> 3) make nsdeps
>
> I used 'allmodconfig' for the above steps to ensure all occurrences are
> patched.
>
> Defining DEFAULT_SYMBOL_NAMESPACE in the Makefile is not trivial in this
> case as not only watchdog_core is defined in drivers/watchdog/Makefile.
> Hence this patch uses the variant of using the EXPORT_SYMBOL_NS* macros
> to export into a different namespace.
>
> An alternative to this patch would be a single definition line before
> any use of EXPORT_SYMBOL*:
> #define DEFAULT_SYMBOL_NAMESPACE WATCHDOG_CORE
>
> This patch serves as a reference on how to use the symbol namespaces.
>
> Reviewed-by: Greg Kroah-Hartman <[email protected]>
> Signed-off-by: Matthias Maennich <[email protected]>
As mentioned before, I am opposed to this set of changes. I don't see
the point of restricting the use of exported symbols in WATCHDOG_CORE.
Guenter
> ---
> drivers/hwmon/ftsteutates.c | 1 +
> drivers/hwmon/sch56xx-common.c | 1 +
> drivers/rtc/rtc-abx80x.c | 1 +
> drivers/watchdog/armada_37xx_wdt.c | 1 +
> drivers/watchdog/asm9260_wdt.c | 1 +
> drivers/watchdog/aspeed_wdt.c | 1 +
> drivers/watchdog/at91sam9_wdt.c | 1 +
> drivers/watchdog/atlas7_wdt.c | 1 +
> drivers/watchdog/bcm2835_wdt.c | 1 +
> drivers/watchdog/bcm47xx_wdt.c | 1 +
> drivers/watchdog/bcm7038_wdt.c | 1 +
> drivers/watchdog/bcm_kona_wdt.c | 1 +
> drivers/watchdog/bd70528_wdt.c | 1 +
> drivers/watchdog/cadence_wdt.c | 1 +
> drivers/watchdog/da9052_wdt.c | 1 +
> drivers/watchdog/da9055_wdt.c | 1 +
> drivers/watchdog/da9062_wdt.c | 1 +
> drivers/watchdog/da9063_wdt.c | 1 +
> drivers/watchdog/davinci_wdt.c | 1 +
> drivers/watchdog/digicolor_wdt.c | 1 +
> drivers/watchdog/dw_wdt.c | 1 +
> drivers/watchdog/ebc-c384_wdt.c | 1 +
> drivers/watchdog/ep93xx_wdt.c | 1 +
> drivers/watchdog/ftwdt010_wdt.c | 1 +
> drivers/watchdog/gpio_wdt.c | 1 +
> drivers/watchdog/hpwdt.c | 1 +
> drivers/watchdog/i6300esb.c | 1 +
> drivers/watchdog/iTCO_wdt.c | 1 +
> drivers/watchdog/ie6xx_wdt.c | 1 +
> drivers/watchdog/imgpdc_wdt.c | 1 +
> drivers/watchdog/imx2_wdt.c | 1 +
> drivers/watchdog/intel-mid_wdt.c | 1 +
> drivers/watchdog/it87_wdt.c | 1 +
> drivers/watchdog/kempld_wdt.c | 1 +
> drivers/watchdog/lpc18xx_wdt.c | 1 +
> drivers/watchdog/max63xx_wdt.c | 1 +
> drivers/watchdog/max77620_wdt.c | 1 +
> drivers/watchdog/mei_wdt.c | 1 +
> drivers/watchdog/mena21_wdt.c | 1 +
> drivers/watchdog/menf21bmc_wdt.c | 1 +
> drivers/watchdog/menz69_wdt.c | 1 +
> drivers/watchdog/meson_gxbb_wdt.c | 1 +
> drivers/watchdog/meson_wdt.c | 1 +
> drivers/watchdog/mlx_wdt.c | 1 +
> drivers/watchdog/moxart_wdt.c | 1 +
> drivers/watchdog/mtk_wdt.c | 1 +
> drivers/watchdog/ni903x_wdt.c | 1 +
> drivers/watchdog/nic7018_wdt.c | 1 +
> drivers/watchdog/npcm_wdt.c | 1 +
> drivers/watchdog/of_xilinx_wdt.c | 1 +
> drivers/watchdog/omap_wdt.c | 1 +
> drivers/watchdog/pm8916_wdt.c | 1 +
> drivers/watchdog/qcom-wdt.c | 1 +
> drivers/watchdog/rave-sp-wdt.c | 1 +
> drivers/watchdog/renesas_wdt.c | 1 +
> drivers/watchdog/retu_wdt.c | 1 +
> drivers/watchdog/rn5t618_wdt.c | 1 +
> drivers/watchdog/rza_wdt.c | 1 +
> drivers/watchdog/s3c2410_wdt.c | 1 +
> drivers/watchdog/sama5d4_wdt.c | 1 +
> drivers/watchdog/sirfsoc_wdt.c | 1 +
> drivers/watchdog/softdog.c | 1 +
> drivers/watchdog/sp5100_tco.c | 1 +
> drivers/watchdog/sprd_wdt.c | 1 +
> drivers/watchdog/st_lpc_wdt.c | 1 +
> drivers/watchdog/stmp3xxx_rtc_wdt.c | 1 +
> drivers/watchdog/stpmic1_wdt.c | 1 +
> drivers/watchdog/sunxi_wdt.c | 1 +
> drivers/watchdog/tangox_wdt.c | 1 +
> drivers/watchdog/tegra_wdt.c | 1 +
> drivers/watchdog/tqmx86_wdt.c | 1 +
> drivers/watchdog/ts4800_wdt.c | 1 +
> drivers/watchdog/ts72xx_wdt.c | 1 +
> drivers/watchdog/twl4030_wdt.c | 1 +
> drivers/watchdog/uniphier_wdt.c | 1 +
> drivers/watchdog/via_wdt.c | 1 +
> drivers/watchdog/w83627hf_wdt.c | 1 +
> drivers/watchdog/watchdog_core.c | 10 +++++-----
> drivers/watchdog/wdat_wdt.c | 1 +
> drivers/watchdog/wm831x_wdt.c | 1 +
> drivers/watchdog/wm8350_wdt.c | 1 +
> drivers/watchdog/xen_wdt.c | 1 +
> drivers/watchdog/ziirave_wdt.c | 1 +
> 83 files changed, 87 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/hwmon/ftsteutates.c b/drivers/hwmon/ftsteutates.c
> index 371ce7745f5e..fa67f7c565be 100644
> --- a/drivers/hwmon/ftsteutates.c
> +++ b/drivers/hwmon/ftsteutates.c
> @@ -830,3 +830,4 @@ module_i2c_driver(fts_driver);
> MODULE_AUTHOR("Thilo Cestonaro <[email protected]>");
> MODULE_DESCRIPTION("FTS Teutates driver");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/hwmon/sch56xx-common.c b/drivers/hwmon/sch56xx-common.c
> index 6c84780e358e..06dd840f3bf7 100644
> --- a/drivers/hwmon/sch56xx-common.c
> +++ b/drivers/hwmon/sch56xx-common.c
> @@ -571,6 +571,7 @@ static void __exit sch56xx_exit(void)
> MODULE_DESCRIPTION("SMSC SCH56xx Hardware Monitoring Common Code");
> MODULE_AUTHOR("Hans de Goede <[email protected]>");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
>
> module_init(sch56xx_init);
> module_exit(sch56xx_exit);
> diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c
> index 73830670a41f..3ff3b96d14d7 100644
> --- a/drivers/rtc/rtc-abx80x.c
> +++ b/drivers/rtc/rtc-abx80x.c
> @@ -880,3 +880,4 @@ MODULE_AUTHOR("Philippe De Muyter <[email protected]>");
> MODULE_AUTHOR("Alexandre Belloni <[email protected]>");
> MODULE_DESCRIPTION("Abracon ABX80X RTC driver");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/armada_37xx_wdt.c b/drivers/watchdog/armada_37xx_wdt.c
> index e5dcb26d85f0..00e153ae70eb 100644
> --- a/drivers/watchdog/armada_37xx_wdt.c
> +++ b/drivers/watchdog/armada_37xx_wdt.c
> @@ -370,4 +370,5 @@ MODULE_AUTHOR("Marek Behun <[email protected]>");
> MODULE_DESCRIPTION("Armada 37xx CPU Watchdog");
>
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("platform:armada_37xx_wdt");
> diff --git a/drivers/watchdog/asm9260_wdt.c b/drivers/watchdog/asm9260_wdt.c
> index 45047e514b8e..fd7289df2cb3 100644
> --- a/drivers/watchdog/asm9260_wdt.c
> +++ b/drivers/watchdog/asm9260_wdt.c
> @@ -374,3 +374,4 @@ module_platform_driver(asm9260_wdt_driver);
> MODULE_DESCRIPTION("asm9260 WatchDog Timer Driver");
> MODULE_AUTHOR("Oleksij Rempel <[email protected]>");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
> index cc71861e033a..2607158965d6 100644
> --- a/drivers/watchdog/aspeed_wdt.c
> +++ b/drivers/watchdog/aspeed_wdt.c
> @@ -334,3 +334,4 @@ module_exit(aspeed_wdt_exit);
>
> MODULE_DESCRIPTION("Aspeed Watchdog Driver");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/at91sam9_wdt.c b/drivers/watchdog/at91sam9_wdt.c
> index 292b5a1ca831..e7aa31fe4336 100644
> --- a/drivers/watchdog/at91sam9_wdt.c
> +++ b/drivers/watchdog/at91sam9_wdt.c
> @@ -416,3 +416,4 @@ module_platform_driver_probe(at91wdt_driver, at91wdt_probe);
> MODULE_AUTHOR("Renaud CERRATO <[email protected]>");
> MODULE_DESCRIPTION("Watchdog driver for Atmel AT91SAM9x processors");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/atlas7_wdt.c b/drivers/watchdog/atlas7_wdt.c
> index 9bfe650d802f..f67e6f101102 100644
> --- a/drivers/watchdog/atlas7_wdt.c
> +++ b/drivers/watchdog/atlas7_wdt.c
> @@ -218,4 +218,5 @@ module_platform_driver(atlas7_wdt_driver);
> MODULE_DESCRIPTION("CSRatlas7 watchdog driver");
> MODULE_AUTHOR("Guo Zeng <[email protected]>");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("platform:atlas7-wdt");
> diff --git a/drivers/watchdog/bcm2835_wdt.c b/drivers/watchdog/bcm2835_wdt.c
> index dec6ca019bea..2f41b8a6e2f6 100644
> --- a/drivers/watchdog/bcm2835_wdt.c
> +++ b/drivers/watchdog/bcm2835_wdt.c
> @@ -242,3 +242,4 @@ MODULE_ALIAS("platform:bcm2835-wdt");
> MODULE_AUTHOR("Lubomir Rintel <[email protected]>");
> MODULE_DESCRIPTION("Driver for Broadcom BCM2835 watchdog timer");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/bcm47xx_wdt.c b/drivers/watchdog/bcm47xx_wdt.c
> index 05425c1dfd4c..231009f01024 100644
> --- a/drivers/watchdog/bcm47xx_wdt.c
> +++ b/drivers/watchdog/bcm47xx_wdt.c
> @@ -241,3 +241,4 @@ MODULE_AUTHOR("Aleksandar Radovanovic");
> MODULE_AUTHOR("Hauke Mehrtens <[email protected]>");
> MODULE_DESCRIPTION("Watchdog driver for Broadcom BCM47xx");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/bcm7038_wdt.c b/drivers/watchdog/bcm7038_wdt.c
> index 979caa18d3c8..e66184997775 100644
> --- a/drivers/watchdog/bcm7038_wdt.c
> +++ b/drivers/watchdog/bcm7038_wdt.c
> @@ -212,5 +212,6 @@ module_param(nowayout, bool, 0);
> MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
> __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_DESCRIPTION("Driver for Broadcom 7038 SoCs Watchdog");
> MODULE_AUTHOR("Justin Chen");
> diff --git a/drivers/watchdog/bcm_kona_wdt.c b/drivers/watchdog/bcm_kona_wdt.c
> index eb850a8d19df..5b5a6a76c1aa 100644
> --- a/drivers/watchdog/bcm_kona_wdt.c
> +++ b/drivers/watchdog/bcm_kona_wdt.c
> @@ -339,3 +339,4 @@ MODULE_ALIAS("platform:" BCM_KONA_WDT_NAME);
> MODULE_AUTHOR("Markus Mayer <[email protected]>");
> MODULE_DESCRIPTION("Broadcom Kona Watchdog Driver");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/bd70528_wdt.c b/drivers/watchdog/bd70528_wdt.c
> index b0152fef4fc7..790748a3a30a 100644
> --- a/drivers/watchdog/bd70528_wdt.c
> +++ b/drivers/watchdog/bd70528_wdt.c
> @@ -288,3 +288,4 @@ module_platform_driver(bd70528_wdt);
> MODULE_AUTHOR("Matti Vaittinen <[email protected]>");
> MODULE_DESCRIPTION("BD70528 watchdog driver");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/cadence_wdt.c b/drivers/watchdog/cadence_wdt.c
> index f8d4e91d0383..a44f3140656e 100644
> --- a/drivers/watchdog/cadence_wdt.c
> +++ b/drivers/watchdog/cadence_wdt.c
> @@ -438,3 +438,4 @@ module_platform_driver(cdns_wdt_driver);
> MODULE_AUTHOR("Xilinx, Inc.");
> MODULE_DESCRIPTION("Watchdog driver for Cadence WDT");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/da9052_wdt.c b/drivers/watchdog/da9052_wdt.c
> index d708c091bf1b..a5ceea0503bb 100644
> --- a/drivers/watchdog/da9052_wdt.c
> +++ b/drivers/watchdog/da9052_wdt.c
> @@ -191,4 +191,5 @@ module_platform_driver(da9052_wdt_driver);
> MODULE_AUTHOR("Anthony Olech <[email protected]>");
> MODULE_DESCRIPTION("DA9052 SM Device Driver");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("platform:da9052-watchdog");
> diff --git a/drivers/watchdog/da9055_wdt.c b/drivers/watchdog/da9055_wdt.c
> index 389a4bdd208c..05b075f2ea90 100644
> --- a/drivers/watchdog/da9055_wdt.c
> +++ b/drivers/watchdog/da9055_wdt.c
> @@ -166,4 +166,5 @@ module_platform_driver(da9055_wdt_driver);
> MODULE_AUTHOR("David Dajun Chen <[email protected]>");
> MODULE_DESCRIPTION("DA9055 watchdog");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("platform:da9055-watchdog");
> diff --git a/drivers/watchdog/da9062_wdt.c b/drivers/watchdog/da9062_wdt.c
> index e149e66a6ea9..dfc2025d36ba 100644
> --- a/drivers/watchdog/da9062_wdt.c
> +++ b/drivers/watchdog/da9062_wdt.c
> @@ -232,4 +232,5 @@ module_platform_driver(da9062_wdt_driver);
> MODULE_AUTHOR("S Twiss <[email protected]>");
> MODULE_DESCRIPTION("WDT device driver for Dialog DA9062 and DA9061");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("platform:da9062-watchdog");
> diff --git a/drivers/watchdog/da9063_wdt.c b/drivers/watchdog/da9063_wdt.c
> index 3d65e92a4e3f..ae0cb7011762 100644
> --- a/drivers/watchdog/da9063_wdt.c
> +++ b/drivers/watchdog/da9063_wdt.c
> @@ -239,4 +239,5 @@ module_platform_driver(da9063_wdt_driver);
> MODULE_AUTHOR("Mariusz Wojtasik <[email protected]>");
> MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG);
> diff --git a/drivers/watchdog/davinci_wdt.c b/drivers/watchdog/davinci_wdt.c
> index 2b3f3cd382ef..4fa01dfa4edb 100644
> --- a/drivers/watchdog/davinci_wdt.c
> +++ b/drivers/watchdog/davinci_wdt.c
> @@ -274,4 +274,5 @@ MODULE_PARM_DESC(heartbeat,
> __MODULE_STRING(DEFAULT_HEARTBEAT));
>
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("platform:davinci-wdt");
> diff --git a/drivers/watchdog/digicolor_wdt.c b/drivers/watchdog/digicolor_wdt.c
> index 073d37867f47..ed86cf879dae 100644
> --- a/drivers/watchdog/digicolor_wdt.c
> +++ b/drivers/watchdog/digicolor_wdt.c
> @@ -161,3 +161,4 @@ module_platform_driver(dc_wdt_driver);
> MODULE_AUTHOR("Baruch Siach <[email protected]>");
> MODULE_DESCRIPTION("Driver for Conexant Digicolor watchdog timer");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
> index fef7c61f5555..e98ccb38eb1d 100644
> --- a/drivers/watchdog/dw_wdt.c
> +++ b/drivers/watchdog/dw_wdt.c
> @@ -340,3 +340,4 @@ module_platform_driver(dw_wdt_driver);
> MODULE_AUTHOR("Jamie Iles");
> MODULE_DESCRIPTION("Synopsys DesignWare Watchdog Driver");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/ebc-c384_wdt.c b/drivers/watchdog/ebc-c384_wdt.c
> index 8ef4b0df3855..7e4349472745 100644
> --- a/drivers/watchdog/ebc-c384_wdt.c
> +++ b/drivers/watchdog/ebc-c384_wdt.c
> @@ -139,4 +139,5 @@ module_exit(ebc_c384_wdt_exit);
> MODULE_AUTHOR("William Breathitt Gray <[email protected]>");
> MODULE_DESCRIPTION("WinSystems EBC-C384 watchdog timer driver");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("isa:" MODULE_NAME);
> diff --git a/drivers/watchdog/ep93xx_wdt.c b/drivers/watchdog/ep93xx_wdt.c
> index 38e26f160b9a..edfa422896d7 100644
> --- a/drivers/watchdog/ep93xx_wdt.c
> +++ b/drivers/watchdog/ep93xx_wdt.c
> @@ -144,3 +144,4 @@ MODULE_AUTHOR("Alessandro Zummo <[email protected]>");
> MODULE_AUTHOR("H Hartley Sweeten <[email protected]>");
> MODULE_DESCRIPTION("EP93xx Watchdog");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/ftwdt010_wdt.c b/drivers/watchdog/ftwdt010_wdt.c
> index 21dcc7765688..c19186bc00b6 100644
> --- a/drivers/watchdog/ftwdt010_wdt.c
> +++ b/drivers/watchdog/ftwdt010_wdt.c
> @@ -227,3 +227,4 @@ module_platform_driver(ftwdt010_wdt_driver);
> MODULE_AUTHOR("Linus Walleij");
> MODULE_DESCRIPTION("Watchdog driver for Faraday Technology FTWDT010");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/gpio_wdt.c b/drivers/watchdog/gpio_wdt.c
> index 0923201ce874..6a90a7ecadeb 100644
> --- a/drivers/watchdog/gpio_wdt.c
> +++ b/drivers/watchdog/gpio_wdt.c
> @@ -194,3 +194,4 @@ module_platform_driver(gpio_wdt_driver);
> MODULE_AUTHOR("Alexander Shiyan <[email protected]>");
> MODULE_DESCRIPTION("GPIO Watchdog");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/hpwdt.c b/drivers/watchdog/hpwdt.c
> index 7d34bcf1c45b..fb4d228a0d7e 100644
> --- a/drivers/watchdog/hpwdt.c
> +++ b/drivers/watchdog/hpwdt.c
> @@ -386,6 +386,7 @@ static struct pci_driver hpwdt_driver = {
> MODULE_AUTHOR("Tom Mingarelli");
> MODULE_DESCRIPTION("hpe watchdog driver");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_VERSION(HPWDT_VERSION);
>
> module_param(soft_margin, int, 0);
> diff --git a/drivers/watchdog/i6300esb.c b/drivers/watchdog/i6300esb.c
> index a30835f547b3..700a8c6cae00 100644
> --- a/drivers/watchdog/i6300esb.c
> +++ b/drivers/watchdog/i6300esb.c
> @@ -351,3 +351,4 @@ module_pci_driver(esb_driver);
> MODULE_AUTHOR("Ross Biro and David H?rdeman");
> MODULE_DESCRIPTION("Watchdog driver for Intel 6300ESB chipsets");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
> index c559f706ae7e..454d8ff3edc1 100644
> --- a/drivers/watchdog/iTCO_wdt.c
> +++ b/drivers/watchdog/iTCO_wdt.c
> @@ -632,4 +632,5 @@ MODULE_AUTHOR("Wim Van Sebroeck <[email protected]>");
> MODULE_DESCRIPTION("Intel TCO WatchDog Timer Driver");
> MODULE_VERSION(DRV_VERSION);
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("platform:" DRV_NAME);
> diff --git a/drivers/watchdog/ie6xx_wdt.c b/drivers/watchdog/ie6xx_wdt.c
> index 8f28993fab8b..76bcff28eaf9 100644
> --- a/drivers/watchdog/ie6xx_wdt.c
> +++ b/drivers/watchdog/ie6xx_wdt.c
> @@ -314,4 +314,5 @@ module_exit(ie6xx_wdt_exit);
> MODULE_AUTHOR("Alexander Stein <[email protected]>");
> MODULE_DESCRIPTION("Intel Atom E6xx Watchdog Device Driver");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("platform:" DRIVER_NAME);
> diff --git a/drivers/watchdog/imgpdc_wdt.c b/drivers/watchdog/imgpdc_wdt.c
> index b57ff3787052..6fe0fd7c0719 100644
> --- a/drivers/watchdog/imgpdc_wdt.c
> +++ b/drivers/watchdog/imgpdc_wdt.c
> @@ -314,3 +314,4 @@ MODULE_AUTHOR("Jude Abraham <[email protected]>");
> MODULE_AUTHOR("Naidu Tellapati <[email protected]>");
> MODULE_DESCRIPTION("Imagination Technologies PDC Watchdog Timer Driver");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c
> index 32af3974e6bb..dc6d4132ec1f 100644
> --- a/drivers/watchdog/imx2_wdt.c
> +++ b/drivers/watchdog/imx2_wdt.c
> @@ -433,4 +433,5 @@ module_platform_driver_probe(imx2_wdt_driver, imx2_wdt_probe);
> MODULE_AUTHOR("Wolfram Sang");
> MODULE_DESCRIPTION("Watchdog driver for IMX2 and later");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("platform:" DRIVER_NAME);
> diff --git a/drivers/watchdog/intel-mid_wdt.c b/drivers/watchdog/intel-mid_wdt.c
> index 2cdbd37c700c..b859fd6d263b 100644
> --- a/drivers/watchdog/intel-mid_wdt.c
> +++ b/drivers/watchdog/intel-mid_wdt.c
> @@ -181,3 +181,4 @@ module_platform_driver(mid_wdt_driver);
> MODULE_AUTHOR("David Cohen <[email protected]>");
> MODULE_DESCRIPTION("Watchdog Driver for Intel MID platform");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/it87_wdt.c b/drivers/watchdog/it87_wdt.c
> index a4b71ebc8cab..610f5cdebf72 100644
> --- a/drivers/watchdog/it87_wdt.c
> +++ b/drivers/watchdog/it87_wdt.c
> @@ -354,3 +354,4 @@ module_exit(it87_wdt_exit);
> MODULE_AUTHOR("Oliver Schuster");
> MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/kempld_wdt.c b/drivers/watchdog/kempld_wdt.c
> index 40bd518ed873..20a40e221dbb 100644
> --- a/drivers/watchdog/kempld_wdt.c
> +++ b/drivers/watchdog/kempld_wdt.c
> @@ -550,3 +550,4 @@ module_platform_driver(kempld_wdt_driver);
> MODULE_DESCRIPTION("KEM PLD Watchdog Driver");
> MODULE_AUTHOR("Michael Brunner <[email protected]>");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/lpc18xx_wdt.c b/drivers/watchdog/lpc18xx_wdt.c
> index 78cf11c94941..4e34a4bd0b24 100644
> --- a/drivers/watchdog/lpc18xx_wdt.c
> +++ b/drivers/watchdog/lpc18xx_wdt.c
> @@ -316,3 +316,4 @@ module_platform_driver(lpc18xx_wdt_driver);
> MODULE_AUTHOR("Ariel D'Alessandro <[email protected]>");
> MODULE_DESCRIPTION("NXP LPC18xx Watchdog Timer Driver");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/max63xx_wdt.c b/drivers/watchdog/max63xx_wdt.c
> index 3a899628a834..053c9285adac 100644
> --- a/drivers/watchdog/max63xx_wdt.c
> +++ b/drivers/watchdog/max63xx_wdt.c
> @@ -284,3 +284,4 @@ MODULE_PARM_DESC(nodelay,
> "(max6373/74 only, default=0)");
>
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/max77620_wdt.c b/drivers/watchdog/max77620_wdt.c
> index be6a53c30002..304817d379a7 100644
> --- a/drivers/watchdog/max77620_wdt.c
> +++ b/drivers/watchdog/max77620_wdt.c
> @@ -209,3 +209,4 @@ MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
>
> MODULE_AUTHOR("Laxman Dewangan <[email protected]>");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/mei_wdt.c b/drivers/watchdog/mei_wdt.c
> index 5391bf3e6b11..5e03226cada1 100644
> --- a/drivers/watchdog/mei_wdt.c
> +++ b/drivers/watchdog/mei_wdt.c
> @@ -662,4 +662,5 @@ module_mei_cl_driver(mei_wdt_driver);
>
> MODULE_AUTHOR("Intel Corporation");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_DESCRIPTION("Device driver for Intel MEI iAMT watchdog");
> diff --git a/drivers/watchdog/mena21_wdt.c b/drivers/watchdog/mena21_wdt.c
> index 99d2359d5a8a..b759c66f1446 100644
> --- a/drivers/watchdog/mena21_wdt.c
> +++ b/drivers/watchdog/mena21_wdt.c
> @@ -225,4 +225,5 @@ module_platform_driver(a21_wdt_driver);
> MODULE_AUTHOR("MEN Mikro Elektronik");
> MODULE_DESCRIPTION("MEN A21 Watchdog");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("platform:a21-watchdog");
> diff --git a/drivers/watchdog/menf21bmc_wdt.c b/drivers/watchdog/menf21bmc_wdt.c
> index 81ebdfc371f4..358881618e2f 100644
> --- a/drivers/watchdog/menf21bmc_wdt.c
> +++ b/drivers/watchdog/menf21bmc_wdt.c
> @@ -181,4 +181,5 @@ module_platform_driver(menf21bmc_wdt);
> MODULE_DESCRIPTION("MEN 14F021P00 BMC Watchdog driver");
> MODULE_AUTHOR("Andreas Werner <[email protected]>");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("platform:menf21bmc_wdt");
> diff --git a/drivers/watchdog/menz69_wdt.c b/drivers/watchdog/menz69_wdt.c
> index ed18238c5407..d13fcfc0f59c 100644
> --- a/drivers/watchdog/menz69_wdt.c
> +++ b/drivers/watchdog/menz69_wdt.c
> @@ -167,4 +167,5 @@ module_mcb_driver(men_z069_driver);
>
> MODULE_AUTHOR("Johannes Thumshirn <[email protected]>");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("mcb:16z069");
> diff --git a/drivers/watchdog/meson_gxbb_wdt.c b/drivers/watchdog/meson_gxbb_wdt.c
> index d17c1a6ed723..f30f85380679 100644
> --- a/drivers/watchdog/meson_gxbb_wdt.c
> +++ b/drivers/watchdog/meson_gxbb_wdt.c
> @@ -204,3 +204,4 @@ module_platform_driver(meson_gxbb_wdt_driver);
> MODULE_AUTHOR("Neil Armstrong <[email protected]>");
> MODULE_DESCRIPTION("Amlogic Meson GXBB Watchdog timer driver");
> MODULE_LICENSE("Dual BSD/GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/meson_wdt.c b/drivers/watchdog/meson_wdt.c
> index 459f3ae02c91..0d60bb5aa688 100644
> --- a/drivers/watchdog/meson_wdt.c
> +++ b/drivers/watchdog/meson_wdt.c
> @@ -228,5 +228,6 @@ MODULE_PARM_DESC(nowayout,
> __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
>
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_AUTHOR("Carlo Caione <[email protected]>");
> MODULE_DESCRIPTION("Meson Watchdog Timer Driver");
> diff --git a/drivers/watchdog/mlx_wdt.c b/drivers/watchdog/mlx_wdt.c
> index 03b9ac4b99af..2df48a6ed04b 100644
> --- a/drivers/watchdog/mlx_wdt.c
> +++ b/drivers/watchdog/mlx_wdt.c
> @@ -287,4 +287,5 @@ module_platform_driver(mlxreg_wdt_driver);
> MODULE_AUTHOR("Michael Shych <[email protected]>");
> MODULE_DESCRIPTION("Mellanox watchdog driver");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("platform:mlx-wdt");
> diff --git a/drivers/watchdog/moxart_wdt.c b/drivers/watchdog/moxart_wdt.c
> index 6340a1f5f471..02dbfe2accfa 100644
> --- a/drivers/watchdog/moxart_wdt.c
> +++ b/drivers/watchdog/moxart_wdt.c
> @@ -164,4 +164,5 @@ MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds");
>
> MODULE_DESCRIPTION("MOXART watchdog driver");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_AUTHOR("Jonas Jensen <[email protected]>");
> diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
> index 9c3d0033260d..074c04324738 100644
> --- a/drivers/watchdog/mtk_wdt.c
> +++ b/drivers/watchdog/mtk_wdt.c
> @@ -247,6 +247,7 @@ MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
> __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
>
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_AUTHOR("Matthias Brugger <[email protected]>");
> MODULE_DESCRIPTION("Mediatek WatchDog Timer Driver");
> MODULE_VERSION(DRV_VERSION);
> diff --git a/drivers/watchdog/ni903x_wdt.c b/drivers/watchdog/ni903x_wdt.c
> index 4cebad324b20..724d47f2f325 100644
> --- a/drivers/watchdog/ni903x_wdt.c
> +++ b/drivers/watchdog/ni903x_wdt.c
> @@ -255,3 +255,4 @@ MODULE_DESCRIPTION("NI 903x Watchdog");
> MODULE_AUTHOR("Jeff Westfahl <[email protected]>");
> MODULE_AUTHOR("Kyle Roeschley <[email protected]>");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/nic7018_wdt.c b/drivers/watchdog/nic7018_wdt.c
> index 2a46cc662943..efe0f188c79a 100644
> --- a/drivers/watchdog/nic7018_wdt.c
> +++ b/drivers/watchdog/nic7018_wdt.c
> @@ -250,3 +250,4 @@ module_platform_driver(watchdog_driver);
> MODULE_DESCRIPTION("National Instruments NIC7018 Watchdog driver");
> MODULE_AUTHOR("Hui Chun Ong <[email protected]>");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/npcm_wdt.c b/drivers/watchdog/npcm_wdt.c
> index 9c773c3d6d5d..aa2022a44985 100644
> --- a/drivers/watchdog/npcm_wdt.c
> +++ b/drivers/watchdog/npcm_wdt.c
> @@ -248,3 +248,4 @@ module_platform_driver(npcm_wdt_driver);
> MODULE_AUTHOR("Joel Stanley");
> MODULE_DESCRIPTION("Watchdog driver for NPCM");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/of_xilinx_wdt.c b/drivers/watchdog/of_xilinx_wdt.c
> index 7fe4f7c3f7ce..8d93e2089c6d 100644
> --- a/drivers/watchdog/of_xilinx_wdt.c
> +++ b/drivers/watchdog/of_xilinx_wdt.c
> @@ -308,3 +308,4 @@ module_platform_driver(xwdt_driver);
> MODULE_AUTHOR("Alejandro Cabrera <[email protected]>");
> MODULE_DESCRIPTION("Xilinx Watchdog driver");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/omap_wdt.c b/drivers/watchdog/omap_wdt.c
> index 9b91882fe3c4..49565608924a 100644
> --- a/drivers/watchdog/omap_wdt.c
> +++ b/drivers/watchdog/omap_wdt.c
> @@ -375,4 +375,5 @@ module_platform_driver(omap_wdt_driver);
>
> MODULE_AUTHOR("George G. Davis");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("platform:omap_wdt");
> diff --git a/drivers/watchdog/pm8916_wdt.c b/drivers/watchdog/pm8916_wdt.c
> index 2d3652004e39..f13c1c2bec07 100644
> --- a/drivers/watchdog/pm8916_wdt.c
> +++ b/drivers/watchdog/pm8916_wdt.c
> @@ -210,3 +210,4 @@ module_platform_driver(pm8916_wdt_driver);
> MODULE_AUTHOR("Loic Poulain <[email protected]>");
> MODULE_DESCRIPTION("Qualcomm pm8916 watchdog driver");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c
> index 7be7f87be28f..1ae02d3b5cb2 100644
> --- a/drivers/watchdog/qcom-wdt.c
> +++ b/drivers/watchdog/qcom-wdt.c
> @@ -272,3 +272,4 @@ module_platform_driver(qcom_watchdog_driver);
>
> MODULE_DESCRIPTION("QCOM KPSS Watchdog Driver");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/rave-sp-wdt.c b/drivers/watchdog/rave-sp-wdt.c
> index 2c95615b6354..7fac3fabfcfb 100644
> --- a/drivers/watchdog/rave-sp-wdt.c
> +++ b/drivers/watchdog/rave-sp-wdt.c
> @@ -329,6 +329,7 @@ module_platform_driver(rave_sp_wdt_driver);
>
> MODULE_DEVICE_TABLE(of, rave_sp_wdt_of_match);
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_AUTHOR("Andrey Vostrikov <[email protected]>");
> MODULE_AUTHOR("Nikita Yushchenko <[email protected]>");
> MODULE_AUTHOR("Andrey Smirnov <[email protected]>");
> diff --git a/drivers/watchdog/renesas_wdt.c b/drivers/watchdog/renesas_wdt.c
> index 00662a8e039c..ec5b1ec6c292 100644
> --- a/drivers/watchdog/renesas_wdt.c
> +++ b/drivers/watchdog/renesas_wdt.c
> @@ -315,4 +315,5 @@ module_platform_driver(rwdt_driver);
>
> MODULE_DESCRIPTION("Renesas WDT Watchdog Driver");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_AUTHOR("Wolfram Sang <[email protected]>");
> diff --git a/drivers/watchdog/retu_wdt.c b/drivers/watchdog/retu_wdt.c
> index 258dfcf9cbda..6a3e2b8e5226 100644
> --- a/drivers/watchdog/retu_wdt.c
> +++ b/drivers/watchdog/retu_wdt.c
> @@ -168,3 +168,4 @@ MODULE_DESCRIPTION("Retu watchdog");
> MODULE_AUTHOR("Amit Kucheria");
> MODULE_AUTHOR("Aaro Koskinen <[email protected]>");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/rn5t618_wdt.c b/drivers/watchdog/rn5t618_wdt.c
> index 234876047431..8f7bc6b1cb64 100644
> --- a/drivers/watchdog/rn5t618_wdt.c
> +++ b/drivers/watchdog/rn5t618_wdt.c
> @@ -191,3 +191,4 @@ module_platform_driver(rn5t618_wdt_driver);
> MODULE_AUTHOR("Beniamino Galvani <[email protected]>");
> MODULE_DESCRIPTION("RN5T618 watchdog driver");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/rza_wdt.c b/drivers/watchdog/rza_wdt.c
> index 7b6c365f7cd3..31ff9acc9af2 100644
> --- a/drivers/watchdog/rza_wdt.c
> +++ b/drivers/watchdog/rza_wdt.c
> @@ -245,3 +245,4 @@ module_platform_driver(rza_wdt_driver);
> MODULE_DESCRIPTION("Renesas RZ/A WDT Driver");
> MODULE_AUTHOR("Chris Brandt <[email protected]>");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
> index 2395f353e52d..5c1800d41411 100644
> --- a/drivers/watchdog/s3c2410_wdt.c
> +++ b/drivers/watchdog/s3c2410_wdt.c
> @@ -739,3 +739,4 @@ module_platform_driver(s3c2410wdt_driver);
> MODULE_AUTHOR("Ben Dooks <[email protected]>, Dimitry Andric <[email protected]>");
> MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/sama5d4_wdt.c b/drivers/watchdog/sama5d4_wdt.c
> index d193a60430b2..725f68703f1e 100644
> --- a/drivers/watchdog/sama5d4_wdt.c
> +++ b/drivers/watchdog/sama5d4_wdt.c
> @@ -321,3 +321,4 @@ module_platform_driver(sama5d4_wdt_driver);
> MODULE_AUTHOR("Atmel Corporation");
> MODULE_DESCRIPTION("Atmel SAMA5D4 Watchdog Timer driver");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/sirfsoc_wdt.c b/drivers/watchdog/sirfsoc_wdt.c
> index 734cf2966ecb..bcb75d9978f0 100644
> --- a/drivers/watchdog/sirfsoc_wdt.c
> +++ b/drivers/watchdog/sirfsoc_wdt.c
> @@ -213,4 +213,5 @@ module_platform_driver(sirfsoc_wdt_driver);
> MODULE_DESCRIPTION("SiRF SoC watchdog driver");
> MODULE_AUTHOR("Xianglong Du <[email protected]>");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("platform:sirfsoc-wdt");
> diff --git a/drivers/watchdog/softdog.c b/drivers/watchdog/softdog.c
> index 3e4885c1545e..8d50543f7340 100644
> --- a/drivers/watchdog/softdog.c
> +++ b/drivers/watchdog/softdog.c
> @@ -165,3 +165,4 @@ module_exit(softdog_exit);
> MODULE_AUTHOR("Alan Cox");
> MODULE_DESCRIPTION("Software Watchdog Device Driver");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c
> index 93bd302ae7c5..716b9c43baf1 100644
> --- a/drivers/watchdog/sp5100_tco.c
> +++ b/drivers/watchdog/sp5100_tco.c
> @@ -486,3 +486,4 @@ module_exit(sp5100_tco_exit);
> MODULE_AUTHOR("Priyanka Gupta");
> MODULE_DESCRIPTION("TCO timer driver for SP5100/SB800 chipset");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/sprd_wdt.c b/drivers/watchdog/sprd_wdt.c
> index edba4e278685..55e883e8dcf4 100644
> --- a/drivers/watchdog/sprd_wdt.c
> +++ b/drivers/watchdog/sprd_wdt.c
> @@ -384,3 +384,4 @@ module_platform_driver(sprd_watchdog_driver);
> MODULE_AUTHOR("Eric Long <[email protected]>");
> MODULE_DESCRIPTION("Spreadtrum Watchdog Timer Controller Driver");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/st_lpc_wdt.c b/drivers/watchdog/st_lpc_wdt.c
> index 14ab6559c748..4a7e6b4694fa 100644
> --- a/drivers/watchdog/st_lpc_wdt.c
> +++ b/drivers/watchdog/st_lpc_wdt.c
> @@ -305,3 +305,4 @@ module_platform_driver(st_wdog_driver);
> MODULE_AUTHOR("David Paris <[email protected]>");
> MODULE_DESCRIPTION("ST LPC Watchdog Driver");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/stmp3xxx_rtc_wdt.c b/drivers/watchdog/stmp3xxx_rtc_wdt.c
> index 7caf3aa71c6a..f1dd033c2b4b 100644
> --- a/drivers/watchdog/stmp3xxx_rtc_wdt.c
> +++ b/drivers/watchdog/stmp3xxx_rtc_wdt.c
> @@ -150,4 +150,5 @@ module_platform_driver(stmp3xxx_wdt_driver);
>
> MODULE_DESCRIPTION("STMP3XXX RTC Watchdog Driver");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_AUTHOR("Wolfram Sang <[email protected]>");
> diff --git a/drivers/watchdog/stpmic1_wdt.c b/drivers/watchdog/stpmic1_wdt.c
> index 45d0c543466f..6cdbe4bf5aaa 100644
> --- a/drivers/watchdog/stpmic1_wdt.c
> +++ b/drivers/watchdog/stpmic1_wdt.c
> @@ -138,3 +138,4 @@ module_platform_driver(stpmic1_wdt_driver);
> MODULE_DESCRIPTION("Watchdog driver for STPMIC1 device");
> MODULE_AUTHOR("Pascal Paillet <[email protected]>");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/sunxi_wdt.c b/drivers/watchdog/sunxi_wdt.c
> index 5f05a45ac187..dea10c79b817 100644
> --- a/drivers/watchdog/sunxi_wdt.c
> +++ b/drivers/watchdog/sunxi_wdt.c
> @@ -289,6 +289,7 @@ MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
> "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
>
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_AUTHOR("Carlo Caione <[email protected]>");
> MODULE_AUTHOR("Henrik Nordstrom <[email protected]>");
> MODULE_DESCRIPTION("sunxi WatchDog Timer Driver");
> diff --git a/drivers/watchdog/tangox_wdt.c b/drivers/watchdog/tangox_wdt.c
> index 1afb0e9d808c..bc9025d31977 100644
> --- a/drivers/watchdog/tangox_wdt.c
> +++ b/drivers/watchdog/tangox_wdt.c
> @@ -207,3 +207,4 @@ module_platform_driver(tangox_wdt_driver);
> MODULE_AUTHOR("Mans Rullgard <[email protected]>");
> MODULE_DESCRIPTION("SMP86xx/SMP87xx Watchdog driver");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/tegra_wdt.c b/drivers/watchdog/tegra_wdt.c
> index dfe06e506cad..06acd8251928 100644
> --- a/drivers/watchdog/tegra_wdt.c
> +++ b/drivers/watchdog/tegra_wdt.c
> @@ -276,3 +276,4 @@ module_platform_driver(tegra_wdt_driver);
> MODULE_AUTHOR("NVIDIA Corporation");
> MODULE_DESCRIPTION("Tegra Watchdog Driver");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/tqmx86_wdt.c b/drivers/watchdog/tqmx86_wdt.c
> index 72d0b0adde38..35b8bfffa34d 100644
> --- a/drivers/watchdog/tqmx86_wdt.c
> +++ b/drivers/watchdog/tqmx86_wdt.c
> @@ -124,3 +124,4 @@ MODULE_AUTHOR("Andrew Lunn <[email protected]>");
> MODULE_DESCRIPTION("TQMx86 Watchdog");
> MODULE_ALIAS("platform:tqmx86-wdt");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/ts4800_wdt.c b/drivers/watchdog/ts4800_wdt.c
> index c137ad2bd5c3..b07f75f9049b 100644
> --- a/drivers/watchdog/ts4800_wdt.c
> +++ b/drivers/watchdog/ts4800_wdt.c
> @@ -200,4 +200,5 @@ module_platform_driver(ts4800_wdt_driver);
>
> MODULE_AUTHOR("Damien Riegel <[email protected]>");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("platform:ts4800_wdt");
> diff --git a/drivers/watchdog/ts72xx_wdt.c b/drivers/watchdog/ts72xx_wdt.c
> index bf918f5fa131..efd74cfabbf8 100644
> --- a/drivers/watchdog/ts72xx_wdt.c
> +++ b/drivers/watchdog/ts72xx_wdt.c
> @@ -174,4 +174,5 @@ module_platform_driver(ts72xx_wdt_driver);
> MODULE_AUTHOR("Mika Westerberg <[email protected]>");
> MODULE_DESCRIPTION("TS-72xx SBC Watchdog");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("platform:ts72xx-wdt");
> diff --git a/drivers/watchdog/twl4030_wdt.c b/drivers/watchdog/twl4030_wdt.c
> index 355e428c0b99..98bcebe3a0b7 100644
> --- a/drivers/watchdog/twl4030_wdt.c
> +++ b/drivers/watchdog/twl4030_wdt.c
> @@ -123,5 +123,6 @@ module_platform_driver(twl4030_wdt_driver);
>
> MODULE_AUTHOR("Nokia Corporation");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("platform:twl4030_wdt");
>
> diff --git a/drivers/watchdog/uniphier_wdt.c b/drivers/watchdog/uniphier_wdt.c
> index 8e9242c23022..3a6d2d3a8f3c 100644
> --- a/drivers/watchdog/uniphier_wdt.c
> +++ b/drivers/watchdog/uniphier_wdt.c
> @@ -255,3 +255,4 @@ MODULE_PARM_DESC(nowayout,
> MODULE_AUTHOR("Keiji Hayashibara <[email protected]>");
> MODULE_DESCRIPTION("UniPhier Watchdog Device Driver");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/via_wdt.c b/drivers/watchdog/via_wdt.c
> index eeb39f96e72e..899a4fe1d7b6 100644
> --- a/drivers/watchdog/via_wdt.c
> +++ b/drivers/watchdog/via_wdt.c
> @@ -259,3 +259,4 @@ module_pci_driver(wdt_driver);
> MODULE_AUTHOR("Marc Vertes");
> MODULE_DESCRIPTION("Driver for watchdog timer on VIA chipset");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/w83627hf_wdt.c b/drivers/watchdog/w83627hf_wdt.c
> index 38b31e9947aa..b66aea20a96e 100644
> --- a/drivers/watchdog/w83627hf_wdt.c
> +++ b/drivers/watchdog/w83627hf_wdt.c
> @@ -528,5 +528,6 @@ module_init(wdt_init);
> module_exit(wdt_exit);
>
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_AUTHOR("P?draig Brady <[email protected]>");
> MODULE_DESCRIPTION("w83627hf/thf WDT driver");
> diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
> index 21e8085b848b..9deb22af5daa 100644
> --- a/drivers/watchdog/watchdog_core.c
> +++ b/drivers/watchdog/watchdog_core.c
> @@ -145,7 +145,7 @@ int watchdog_init_timeout(struct watchdog_device *wdd,
>
> return ret;
> }
> -EXPORT_SYMBOL_GPL(watchdog_init_timeout);
> +EXPORT_SYMBOL_NS_GPL(watchdog_init_timeout, WATCHDOG_CORE);
>
> static int watchdog_restart_notifier(struct notifier_block *nb,
> unsigned long action, void *data)
> @@ -180,7 +180,7 @@ void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority)
> {
> wdd->restart_nb.priority = priority;
> }
> -EXPORT_SYMBOL_GPL(watchdog_set_restart_priority);
> +EXPORT_SYMBOL_NS_GPL(watchdog_set_restart_priority, WATCHDOG_CORE);
>
> static int __watchdog_register_device(struct watchdog_device *wdd)
> {
> @@ -279,7 +279,7 @@ int watchdog_register_device(struct watchdog_device *wdd)
>
> return ret;
> }
> -EXPORT_SYMBOL_GPL(watchdog_register_device);
> +EXPORT_SYMBOL_NS_GPL(watchdog_register_device, WATCHDOG_CORE);
>
> static void __watchdog_unregister_device(struct watchdog_device *wdd)
> {
> @@ -311,7 +311,7 @@ void watchdog_unregister_device(struct watchdog_device *wdd)
> mutex_unlock(&wtd_deferred_reg_mutex);
> }
>
> -EXPORT_SYMBOL_GPL(watchdog_unregister_device);
> +EXPORT_SYMBOL_NS_GPL(watchdog_unregister_device, WATCHDOG_CORE);
>
> static void devm_watchdog_unregister_device(struct device *dev, void *res)
> {
> @@ -348,7 +348,7 @@ int devm_watchdog_register_device(struct device *dev,
>
> return ret;
> }
> -EXPORT_SYMBOL_GPL(devm_watchdog_register_device);
> +EXPORT_SYMBOL_NS_GPL(devm_watchdog_register_device, WATCHDOG_CORE);
>
> static int __init watchdog_deferred_registration(void)
> {
> diff --git a/drivers/watchdog/wdat_wdt.c b/drivers/watchdog/wdat_wdt.c
> index e7cf41aa26c3..027339a557ce 100644
> --- a/drivers/watchdog/wdat_wdt.c
> +++ b/drivers/watchdog/wdat_wdt.c
> @@ -523,4 +523,5 @@ module_platform_driver(wdat_wdt_driver);
> MODULE_AUTHOR("Mika Westerberg <[email protected]>");
> MODULE_DESCRIPTION("ACPI Hardware Watchdog (WDAT) driver");
> MODULE_LICENSE("GPL v2");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("platform:wdat_wdt");
> diff --git a/drivers/watchdog/wm831x_wdt.c b/drivers/watchdog/wm831x_wdt.c
> index 030ce240620d..a17e2ac251a1 100644
> --- a/drivers/watchdog/wm831x_wdt.c
> +++ b/drivers/watchdog/wm831x_wdt.c
> @@ -282,4 +282,5 @@ module_platform_driver(wm831x_wdt_driver);
> MODULE_AUTHOR("Mark Brown");
> MODULE_DESCRIPTION("WM831x Watchdog");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("platform:wm831x-watchdog");
> diff --git a/drivers/watchdog/wm8350_wdt.c b/drivers/watchdog/wm8350_wdt.c
> index 33c62d51f00a..f81e661662e6 100644
> --- a/drivers/watchdog/wm8350_wdt.c
> +++ b/drivers/watchdog/wm8350_wdt.c
> @@ -175,4 +175,5 @@ module_platform_driver(wm8350_wdt_driver);
> MODULE_AUTHOR("Mark Brown");
> MODULE_DESCRIPTION("WM8350 Watchdog");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> MODULE_ALIAS("platform:wm8350-wdt");
> diff --git a/drivers/watchdog/xen_wdt.c b/drivers/watchdog/xen_wdt.c
> index b343f421dc72..8b21a4b51047 100644
> --- a/drivers/watchdog/xen_wdt.c
> +++ b/drivers/watchdog/xen_wdt.c
> @@ -206,3 +206,4 @@ module_exit(xen_wdt_cleanup_module);
> MODULE_AUTHOR("Jan Beulich <[email protected]>");
> MODULE_DESCRIPTION("Xen WatchDog Timer Driver");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> diff --git a/drivers/watchdog/ziirave_wdt.c b/drivers/watchdog/ziirave_wdt.c
> index dec660c509b3..2d81c7b546f2 100644
> --- a/drivers/watchdog/ziirave_wdt.c
> +++ b/drivers/watchdog/ziirave_wdt.c
> @@ -751,3 +751,4 @@ module_i2c_driver(ziirave_wdt_driver);
> MODULE_AUTHOR("Martyn Welch <[email protected]");
> MODULE_DESCRIPTION("Zodiac Aerospace RAVE Switch Watchdog Processor Driver");
> MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(WATCHDOG_CORE);
> --
> 2.23.0.187.g17f5b7556c-goog
>
On Tue, Sep 03, 2019 at 04:06:35PM +0100, Matthias Maennich wrote:
> Describe using Symbol Namespaces from a perspective of a user. I.e.
> module authors or subsystem maintainers.
>
> Signed-off-by: Matthias Maennich <[email protected]>
Nice, it's good to have stuff to point people at.
Reviewed-by: Greg Kroah-Hartman <[email protected]>
On Wed, Sep 4, 2019 at 1:10 AM Guenter Roeck <[email protected]> wrote:
>
> On Tue, Sep 03, 2019 at 04:06:38PM +0100, Matthias Maennich wrote:
> > Modules using symbols from the WATCHDOG_CORE namespace are required to
> > explicitly import the namespace. This patch was generated with the
> > following steps and serves as a reference to use the symbol namespace
> > feature:
> >
> > 1) Use EXPORT_SYMBOL_NS* macros instead of EXPORT_SYMBOL* for symbols
> > in watchdog_core.c
> > 2) make (see warnings during modpost about missing imports)
> > 3) make nsdeps
> >
> > I used 'allmodconfig' for the above steps to ensure all occurrences are
> > patched.
> >
> > Defining DEFAULT_SYMBOL_NAMESPACE in the Makefile is not trivial in this
> > case as not only watchdog_core is defined in drivers/watchdog/Makefile.
> > Hence this patch uses the variant of using the EXPORT_SYMBOL_NS* macros
> > to export into a different namespace.
> >
> > An alternative to this patch would be a single definition line before
> > any use of EXPORT_SYMBOL*:
> > #define DEFAULT_SYMBOL_NAMESPACE WATCHDOG_CORE
> >
> > This patch serves as a reference on how to use the symbol namespaces.
> >
> > Reviewed-by: Greg Kroah-Hartman <[email protected]>
> > Signed-off-by: Matthias Maennich <[email protected]>
>
> As mentioned before, I am opposed to this set of changes. I don't see
> the point of restricting the use of exported symbols in WATCHDOG_CORE.
>
> Guenter
I agree.
I do not like this patch set either.
Anyway, the last two patches (usb-stroage, watchdog)
are useful to demonstrate
that this has a bad taste.
--
Best Regards
Masahiro Yamada
On Wed, Sep 4, 2019 at 12:07 AM Matthias Maennich <[email protected]> wrote:
>
> As of Linux 5.3-rc7, there are 31207 [1] exported symbols in the kernel.
> That is a growth of roughly 1000 symbols since 4.17 (30206 [2]). There
> seems to be some consensus amongst kernel devs that the export surface
> is too large, and hard to reason about.
>
> Generally, these symbols fall in one of these categories:
> 1) Symbols actually meant for drivers
> 2) Symbols that are only exported because functionality is split over
> multiple modules, yet they really shouldn't be used by modules outside
> of their own subsystem
> 3) Symbols really only meant for in-tree use
>
> When module developers try to upstream their code, it regularly turns
> out that they are using exported symbols that they really shouldn't be
> using. This problem is even bigger for drivers that are currently
> out-of-tree, which may be using many symbols that they shouldn't be
> using, and that break when those symbols are removed or modified.
>
> This patch allows subsystem maintainers to partition their exported
> symbols into separate namespaces, and module authors to import such
> namespaces only when needed.
>
> This allows subsystem maintainers to more easily limit availability of
> these namespaced symbols to other parts of the kernel. It can also be
> used to partition the set of exported symbols for documentation
> purposes; for example, a set of symbols that is really only used for
> debugging could be in a "SUBSYSTEM_DEBUG" namespace.
Why is the namespace helpful to limit the availability of symbols?
External modules would add whatever EXPORT_SYMBOL_NS() needed
to use the symbols.
Nothing would change except that it would increase the code size.
If we introduce the namespace, do symbols no longer
need to be globally unique?
Theoretically, we could do this:
EXPORT_SYMBOL_NS(foo, SUBSYSTEM_A); (for Subsystem-A)
EXPORT_SYMBOL_NS(foo, SUBSYSTEM_B); (for Subsystem-B)
But, I do not see benefit to do so.
We usually prefix symbol names with the sybsystem names
(usb_ ... , watchdog_ ...).
By ensuring the symbol uniqueness,
it is really clear which functions are called.
You can easily grep the source code.
Editors can follow the code with tag files.
Adding namespace just introduces extra complexity.
Thanks.
>
> The series contains two RFC patches that do not need to be merged along
> with the rest of the series, but they serve as a reference for using the
> symbol namespaces. Especially, the watchdog subsystem might not be
> affected by the issues addressed by Symbol Namespaces. I left the patch
> in for reference anyway for demonstration purposes.
>
> I continued the work mainly done by Martijn Coenen.
>
> Changes in v2:
> - Rather than adding and evaluating separate sections __knsimport_NS,
> use modinfo tags to declare the namespaces a module introduces.
> Adjust modpost and the module loader accordingly.
> - Also add support for reading multiple modinfo values for the same tag
> to allow list-like access to modinfo tags.
> - The macros in export.h have been cleaned up to avoid redundancy in the
> macro parameters (ns, nspost, nspost2).
> - The introduction of relative references in the ksymtab entries caused
> a rework of the macros to accommodate that configuration as well.
> - Alignment of kernel_symbol in the ksymtab needed to be fixed to allow
> growing the kernel_symbol struct.
> - Modpost does now also append the namespace suffix to the symbol
> entries in Module.symvers.
> - The configuration option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS allows
> relaxing the enforcement of properly declared namespace imports at
> module loading time.
> - Symbols can be collectively exported into a namespace by defining
> DEFAULT_SYMBOL_NAMESPACE in the corresponding Makefile.
> - The requirement for a very recent coccinelle spatch has been lifted by
> simplifying the script.
> - nsdeps does now ensures MODULE_IMPORT_NS statements are sorted when
> patching the module source files.
> - Some minor bugs have been addressed in nsdeps to allow it to work with
> modules that have more than one source file.
> - The RFC for the usb-storage symbols has been simplified by using
> DEFAULT_SYMBOL_NAMESPACE=USB_STORAGE rather than explicitly exporting
> each and every symbol into that new namespace.
>
> Changes in v3:
> - Reword the documentation for the
> MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS option for clarification.
> - Fix printed required version of spatch in coccinelle script.
> - Adopt kbuild changes for modpost: .mod files are no longer generated
> in .tmp_versions. Similarely, generate the .ns_deps files in the tree
> along with the .mod files. Also, nsdeps now uses modules.order as
> source for the list modules to consider.
> - Add an RFC patch to introduce the namespace WATCHDOG_CORE for symbols
> exported in watchdog_core.c.
>
> Changes in v4:
> - scripts/nsdeps:
> - exit on first error
> - support out-of-tree builds O=...
> - scripts/mod/modpost: make the namespace a separate field when
> exporting to Module.symvers (rather than symbol.NS)
> - scripts/export_report.pl: update for new Module.symvers format
> - include/linux/export.h: fixed style nits
> - kernel/module.c: ensure namespaces are imported before taking a
> reference to the owner module
> - Documentation: document the Symbol Namespace feature and update
> references to Module.symvers and EXPORT_SYMBOL*
>
> This patch series was developed against v5.3-rc7.
>
> [1] git grep "^EXPORT_SYMBOL\w*(" v5.3-rc7 | wc -l
> [2] git grep "^EXPORT_SYMBOL\w*(" v4.17 | wc -l
>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
>
>
> Matthias Maennich (12):
> module: support reading multiple values per modinfo tag
> export: explicitly align struct kernel_symbol
> module: add support for symbol namespaces.
> modpost: add support for symbol namespaces
> module: add config option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
> export: allow definition default namespaces in Makefiles or sources
> modpost: add support for generating namespace dependencies
> scripts: Coccinelle script for namespace dependencies.
> docs: Add documentation for Symbol Namespaces
> usb-storage: remove single-use define for debugging
> RFC: usb-storage: export symbols in USB_STORAGE namespace
> RFC: watchdog: export core symbols in WATCHDOG_CORE namespace
>
> .gitignore | 1 +
> Documentation/kbuild/modules.rst | 7 +-
> Documentation/kbuild/namespaces.rst | 154 ++++++++++++++++++++
> Documentation/kernel-hacking/hacking.rst | 18 +++
> MAINTAINERS | 5 +
> Makefile | 14 +-
> arch/m68k/include/asm/export.h | 1 -
> drivers/hwmon/ftsteutates.c | 1 +
> drivers/hwmon/sch56xx-common.c | 1 +
> drivers/rtc/rtc-abx80x.c | 1 +
> drivers/usb/storage/Makefile | 2 +
> drivers/usb/storage/alauda.c | 1 +
> drivers/usb/storage/cypress_atacb.c | 1 +
> drivers/usb/storage/datafab.c | 1 +
> drivers/usb/storage/debug.h | 2 -
> drivers/usb/storage/ene_ub6250.c | 1 +
> drivers/usb/storage/freecom.c | 1 +
> drivers/usb/storage/isd200.c | 1 +
> drivers/usb/storage/jumpshot.c | 1 +
> drivers/usb/storage/karma.c | 1 +
> drivers/usb/storage/onetouch.c | 1 +
> drivers/usb/storage/realtek_cr.c | 1 +
> drivers/usb/storage/scsiglue.c | 2 +-
> drivers/usb/storage/sddr09.c | 1 +
> drivers/usb/storage/sddr55.c | 1 +
> drivers/usb/storage/shuttle_usbat.c | 1 +
> drivers/usb/storage/uas.c | 1 +
> drivers/watchdog/armada_37xx_wdt.c | 1 +
> drivers/watchdog/asm9260_wdt.c | 1 +
> drivers/watchdog/aspeed_wdt.c | 1 +
> drivers/watchdog/at91sam9_wdt.c | 1 +
> drivers/watchdog/atlas7_wdt.c | 1 +
> drivers/watchdog/bcm2835_wdt.c | 1 +
> drivers/watchdog/bcm47xx_wdt.c | 1 +
> drivers/watchdog/bcm7038_wdt.c | 1 +
> drivers/watchdog/bcm_kona_wdt.c | 1 +
> drivers/watchdog/bd70528_wdt.c | 1 +
> drivers/watchdog/cadence_wdt.c | 1 +
> drivers/watchdog/da9052_wdt.c | 1 +
> drivers/watchdog/da9055_wdt.c | 1 +
> drivers/watchdog/da9062_wdt.c | 1 +
> drivers/watchdog/da9063_wdt.c | 1 +
> drivers/watchdog/davinci_wdt.c | 1 +
> drivers/watchdog/digicolor_wdt.c | 1 +
> drivers/watchdog/dw_wdt.c | 1 +
> drivers/watchdog/ebc-c384_wdt.c | 1 +
> drivers/watchdog/ep93xx_wdt.c | 1 +
> drivers/watchdog/ftwdt010_wdt.c | 1 +
> drivers/watchdog/gpio_wdt.c | 1 +
> drivers/watchdog/hpwdt.c | 1 +
> drivers/watchdog/i6300esb.c | 1 +
> drivers/watchdog/iTCO_wdt.c | 1 +
> drivers/watchdog/ie6xx_wdt.c | 1 +
> drivers/watchdog/imgpdc_wdt.c | 1 +
> drivers/watchdog/imx2_wdt.c | 1 +
> drivers/watchdog/intel-mid_wdt.c | 1 +
> drivers/watchdog/it87_wdt.c | 1 +
> drivers/watchdog/kempld_wdt.c | 1 +
> drivers/watchdog/lpc18xx_wdt.c | 1 +
> drivers/watchdog/max63xx_wdt.c | 1 +
> drivers/watchdog/max77620_wdt.c | 1 +
> drivers/watchdog/mei_wdt.c | 1 +
> drivers/watchdog/mena21_wdt.c | 1 +
> drivers/watchdog/menf21bmc_wdt.c | 1 +
> drivers/watchdog/menz69_wdt.c | 1 +
> drivers/watchdog/meson_gxbb_wdt.c | 1 +
> drivers/watchdog/meson_wdt.c | 1 +
> drivers/watchdog/mlx_wdt.c | 1 +
> drivers/watchdog/moxart_wdt.c | 1 +
> drivers/watchdog/mtk_wdt.c | 1 +
> drivers/watchdog/ni903x_wdt.c | 1 +
> drivers/watchdog/nic7018_wdt.c | 1 +
> drivers/watchdog/npcm_wdt.c | 1 +
> drivers/watchdog/of_xilinx_wdt.c | 1 +
> drivers/watchdog/omap_wdt.c | 1 +
> drivers/watchdog/pm8916_wdt.c | 1 +
> drivers/watchdog/qcom-wdt.c | 1 +
> drivers/watchdog/rave-sp-wdt.c | 1 +
> drivers/watchdog/renesas_wdt.c | 1 +
> drivers/watchdog/retu_wdt.c | 1 +
> drivers/watchdog/rn5t618_wdt.c | 1 +
> drivers/watchdog/rza_wdt.c | 1 +
> drivers/watchdog/s3c2410_wdt.c | 1 +
> drivers/watchdog/sama5d4_wdt.c | 1 +
> drivers/watchdog/sirfsoc_wdt.c | 1 +
> drivers/watchdog/softdog.c | 1 +
> drivers/watchdog/sp5100_tco.c | 1 +
> drivers/watchdog/sprd_wdt.c | 1 +
> drivers/watchdog/st_lpc_wdt.c | 1 +
> drivers/watchdog/stmp3xxx_rtc_wdt.c | 1 +
> drivers/watchdog/stpmic1_wdt.c | 1 +
> drivers/watchdog/sunxi_wdt.c | 1 +
> drivers/watchdog/tangox_wdt.c | 1 +
> drivers/watchdog/tegra_wdt.c | 1 +
> drivers/watchdog/tqmx86_wdt.c | 1 +
> drivers/watchdog/ts4800_wdt.c | 1 +
> drivers/watchdog/ts72xx_wdt.c | 1 +
> drivers/watchdog/twl4030_wdt.c | 1 +
> drivers/watchdog/uniphier_wdt.c | 1 +
> drivers/watchdog/via_wdt.c | 1 +
> drivers/watchdog/w83627hf_wdt.c | 1 +
> drivers/watchdog/watchdog_core.c | 10 +-
> drivers/watchdog/wdat_wdt.c | 1 +
> drivers/watchdog/wm831x_wdt.c | 1 +
> drivers/watchdog/wm8350_wdt.c | 1 +
> drivers/watchdog/xen_wdt.c | 1 +
> drivers/watchdog/ziirave_wdt.c | 1 +
> include/asm-generic/export.h | 14 +-
> include/linux/export.h | 98 +++++++++++--
> include/linux/module.h | 2 +
> init/Kconfig | 13 ++
> kernel/module.c | 67 ++++++++-
> scripts/Makefile.modpost | 4 +-
> scripts/coccinelle/misc/add_namespace.cocci | 23 +++
> scripts/export_report.pl | 2 +-
> scripts/mod/modpost.c | 150 ++++++++++++++++---
> scripts/mod/modpost.h | 9 ++
> scripts/nsdeps | 60 ++++++++
> 118 files changed, 697 insertions(+), 57 deletions(-)
> create mode 100644 Documentation/kbuild/namespaces.rst
> create mode 100644 scripts/coccinelle/misc/add_namespace.cocci
> create mode 100644 scripts/nsdeps
>
> --
> 2.23.0.187.g17f5b7556c-goog
>
--
Best Regards
Masahiro Yamada
On Wed, Sep 4, 2019 at 12:07 AM Matthias Maennich <[email protected]> wrote:
>
> A script that uses the '<module>.ns_deps' files generated by modpost to
> automatically add the required symbol namespace dependencies to each
> module.
>
> Usage:
> 1) Move some symbols to a namespace with EXPORT_SYMBOL_NS() or define
> DEFAULT_SYMBOL_NAMESPACE
> 2) Run 'make' (or 'make modules') and get warnings about modules not
> importing that namespace.
> 3) Run 'make nsdeps' to automatically add required import statements
> to said modules.
>
> This makes it easer for subsystem maintainers to introduce and maintain
> symbol namespaces into their codebase.
>
> Co-developed-by: Martijn Coenen <[email protected]>
> Signed-off-by: Martijn Coenen <[email protected]>
> Acked-by: Julia Lawall <[email protected]>
> Reviewed-by: Greg Kroah-Hartman <[email protected]>
> Signed-off-by: Matthias Maennich <[email protected]>
Without any correct dependency,
this does not work.
$ make clean; make nsdeps
cat: modules.order: No such file or directory
cat: ./modules.order: No such file or directory
I do not see any point in the Makefile changes.
--
Best Regards
Masahiro Yamada
On 9/4/19 1:45 AM, Masahiro Yamada wrote:
> On Wed, Sep 4, 2019 at 1:10 AM Guenter Roeck <[email protected]> wrote:
>>
>> On Tue, Sep 03, 2019 at 04:06:38PM +0100, Matthias Maennich wrote:
>>> Modules using symbols from the WATCHDOG_CORE namespace are required to
>>> explicitly import the namespace. This patch was generated with the
>>> following steps and serves as a reference to use the symbol namespace
>>> feature:
>>>
>>> 1) Use EXPORT_SYMBOL_NS* macros instead of EXPORT_SYMBOL* for symbols
>>> in watchdog_core.c
>>> 2) make (see warnings during modpost about missing imports)
>>> 3) make nsdeps
>>>
>>> I used 'allmodconfig' for the above steps to ensure all occurrences are
>>> patched.
>>>
>>> Defining DEFAULT_SYMBOL_NAMESPACE in the Makefile is not trivial in this
>>> case as not only watchdog_core is defined in drivers/watchdog/Makefile.
>>> Hence this patch uses the variant of using the EXPORT_SYMBOL_NS* macros
>>> to export into a different namespace.
>>>
>>> An alternative to this patch would be a single definition line before
>>> any use of EXPORT_SYMBOL*:
>>> #define DEFAULT_SYMBOL_NAMESPACE WATCHDOG_CORE
>>>
>>> This patch serves as a reference on how to use the symbol namespaces.
>>>
>>> Reviewed-by: Greg Kroah-Hartman <[email protected]>
>>> Signed-off-by: Matthias Maennich <[email protected]>
>>
>> As mentioned before, I am opposed to this set of changes. I don't see
>> the point of restricting the use of exported symbols in WATCHDOG_CORE.
>>
>> Guenter
>
>
> I agree.
>
> I do not like this patch set either.
>
Note that I don't object to the patch set in general. There may be symbols
which only need be exported in the context of a single subsystem or even
driver (if a driver consists of more than one module). For example, a mfd
driver may export symbols which should only be called by its client drivers.
In such a situation, it may well be beneficial to limit the use of exported
symbols.
I am not sure what good that does in practice (if I understand correctly,
a driver only has to declare that it wants to use a restricted use symbol
if it wants to use it), but that is a different question.
Guenter
On Wed, Sep 4, 2019 at 5:12 AM Guenter Roeck <[email protected]> wrote:
>
> Note that I don't object to the patch set in general. There may be symbols
> which only need be exported in the context of a single subsystem or even
> driver (if a driver consists of more than one module). For example, a mfd
> driver may export symbols which should only be called by its client drivers.
> In such a situation, it may well be beneficial to limit the use of exported
> symbols.
I can appreciate this benefit.
> I am not sure what good that does in practice (if I understand correctly,
> a driver only has to declare that it wants to use a restricted use symbol
> if it wants to use it), but that is a different question.
I think this question implies that you are coming from the perspective
of "security" or wanting to restrict access to the underlying
functions, rather than wanting to clean-up the way symbols are handled
for manageability / maintainability purposes (which is the goal, as I
understand it).
HOWEVER, I have one question: If these patches are included, and
someone wants to introduce a bit of code which needs to use two
symbols from different namespaces but with the same name, can that be
done? That is, if driver A has symbol 'foo' and driver B has symbol
'foo' (both in their respective namespaces), and driver C wants to use
A.foo and B.foo, can that be supported?
Matt
--
Matthew Dharm
Former Maintainer, USB Mass Storage driver for Linux
+++ Matthew Dharm [04/09/19 09:16 -0700]:
>On Wed, Sep 4, 2019 at 5:12 AM Guenter Roeck <[email protected]> wrote:
>>
>> Note that I don't object to the patch set in general. There may be symbols
>> which only need be exported in the context of a single subsystem or even
>> driver (if a driver consists of more than one module). For example, a mfd
>> driver may export symbols which should only be called by its client drivers.
>> In such a situation, it may well be beneficial to limit the use of exported
>> symbols.
>
>I can appreciate this benefit.
>
>> I am not sure what good that does in practice (if I understand correctly,
>> a driver only has to declare that it wants to use a restricted use symbol
>> if it wants to use it), but that is a different question.
>
>I think this question implies that you are coming from the perspective
>of "security" or wanting to restrict access to the underlying
>functions, rather than wanting to clean-up the way symbols are handled
>for manageability / maintainability purposes (which is the goal, as I
>understand it).
>
>HOWEVER, I have one question: If these patches are included, and
>someone wants to introduce a bit of code which needs to use two
>symbols from different namespaces but with the same name, can that be
>done? That is, if driver A has symbol 'foo' and driver B has symbol
>'foo' (both in their respective namespaces), and driver C wants to use
>A.foo and B.foo, can that be supported?
As of now, we currently don't support this - modpost will warn if a
symbol is exported more than once (across modules + vmlinux), and the
module loader currently assumes exported symbol names are unique. Do
you have a concrete use case? If there is a strong need for this, I
don't think it'd be too hard to implement.
Thanks,
Jessica
On Thu, Sep 5, 2019 at 12:41 PM Jessica Yu <[email protected]> wrote:
> +++ Matthew Dharm [04/09/19 09:16 -0700]:
> >On Wed, Sep 4, 2019 at 5:12 AM Guenter Roeck <[email protected]> wrote:
> >HOWEVER, I have one question: If these patches are included, and
> >someone wants to introduce a bit of code which needs to use two
> >symbols from different namespaces but with the same name, can that be
> >done? That is, if driver A has symbol 'foo' and driver B has symbol
> >'foo' (both in their respective namespaces), and driver C wants to use
> >A.foo and B.foo, can that be supported?
>
> As of now, we currently don't support this - modpost will warn if a
> symbol is exported more than once (across modules + vmlinux), and the
> module loader currently assumes exported symbol names are unique. Do
> you have a concrete use case? If there is a strong need for this, I
> don't think it'd be too hard to implement.
I think what would prevent this from working in general is that having
two modules with the same exported symbol in different namespaces
won't link if you try to build both modules into the kernel itself.
Arnd
On Thu, Sep 05, 2019 at 12:41:47PM +0200, Jessica Yu wrote:
>+++ Matthew Dharm [04/09/19 09:16 -0700]:
>>On Wed, Sep 4, 2019 at 5:12 AM Guenter Roeck <[email protected]> wrote:
>>>
>>>Note that I don't object to the patch set in general. There may be symbols
>>>which only need be exported in the context of a single subsystem or even
>>>driver (if a driver consists of more than one module). For example, a mfd
>>>driver may export symbols which should only be called by its client drivers.
>>>In such a situation, it may well be beneficial to limit the use of exported
>>>symbols.
>>
>>I can appreciate this benefit.
>>
>>>I am not sure what good that does in practice (if I understand correctly,
>>>a driver only has to declare that it wants to use a restricted use symbol
>>>if it wants to use it), but that is a different question.
>>
>>I think this question implies that you are coming from the perspective
>>of "security" or wanting to restrict access to the underlying
>>functions, rather than wanting to clean-up the way symbols are handled
>>for manageability / maintainability purposes (which is the goal, as I
>>understand it).
The goal of this patch set is to introduce structure into the exported
surface that goes beyond naming conventions like 'usb_*'. So, it is
rather about maintainability then security. In particular, creating the
visibility of which parts of the kernel use which other parts, might
help to find cases where suboptimal choices were made. Maybe already
during development/review.
As Guenter correctly noted, a module is able to declare that it wants to
use a namespace. One idea that came up earlier was to maybe restrict the
namespaces that can actually be imported by modules. But I would see
anything in that direction as beyond the scope of this series.
A nice side effect of having to declare the usage is that it shows up in
modinfo and module users can reason about how the module interacts with
the rest of the kernel.
>>HOWEVER, I have one question: If these patches are included, and
>>someone wants to introduce a bit of code which needs to use two
>>symbols from different namespaces but with the same name, can that be
>>done? That is, if driver A has symbol 'foo' and driver B has symbol
>>'foo' (both in their respective namespaces), and driver C wants to use
>>A.foo and B.foo, can that be supported?
>
>As of now, we currently don't support this - modpost will warn if a
>symbol is exported more than once (across modules + vmlinux), and the
>module loader currently assumes exported symbol names are unique. Do
>you have a concrete use case? If there is a strong need for this, I
>don't think it'd be too hard to implement.
The implementation does not change the fact that symbol names need to be
unique. As Arnd just mentioned in the other thread: the linker will
already fail if two builtin symbols use the same name. It is rather a
tag attached to the symbol.
Cheers,
Matthias
+++ Arnd Bergmann [05/09/19 12:52 +0200]:
>On Thu, Sep 5, 2019 at 12:41 PM Jessica Yu <[email protected]> wrote:
>> +++ Matthew Dharm [04/09/19 09:16 -0700]:
>> >On Wed, Sep 4, 2019 at 5:12 AM Guenter Roeck <[email protected]> wrote:
>
>> >HOWEVER, I have one question: If these patches are included, and
>> >someone wants to introduce a bit of code which needs to use two
>> >symbols from different namespaces but with the same name, can that be
>> >done? That is, if driver A has symbol 'foo' and driver B has symbol
>> >'foo' (both in their respective namespaces), and driver C wants to use
>> >A.foo and B.foo, can that be supported?
>>
>> As of now, we currently don't support this - modpost will warn if a
>> symbol is exported more than once (across modules + vmlinux), and the
>> module loader currently assumes exported symbol names are unique. Do
>> you have a concrete use case? If there is a strong need for this, I
>> don't think it'd be too hard to implement.
>
>I think what would prevent this from working in general is that having
>two modules with the same exported symbol in different namespaces
>won't link if you try to build both modules into the kernel itself.
>
> Arnd
Ah yeah, you are right. I only tried building an identically named
exported symbol in a module and in the kernel, and there I got away
with a modpost warning. But this breaks when building the module into
the kernel, so I guess this is out of the question.
Thanks,
Jessica
On Thu, Sep 5, 2019 at 8:16 PM Jessica Yu <[email protected]> wrote:
>
> +++ Arnd Bergmann [05/09/19 12:52 +0200]:
> >On Thu, Sep 5, 2019 at 12:41 PM Jessica Yu <[email protected]> wrote:
> >> +++ Matthew Dharm [04/09/19 09:16 -0700]:
> >> >On Wed, Sep 4, 2019 at 5:12 AM Guenter Roeck <[email protected]> wrote:
> >
> >> >HOWEVER, I have one question: If these patches are included, and
> >> >someone wants to introduce a bit of code which needs to use two
> >> >symbols from different namespaces but with the same name, can that be
> >> >done? That is, if driver A has symbol 'foo' and driver B has symbol
> >> >'foo' (both in their respective namespaces), and driver C wants to use
> >> >A.foo and B.foo, can that be supported?
> >>
> >> As of now, we currently don't support this - modpost will warn if a
> >> symbol is exported more than once (across modules + vmlinux), and the
> >> module loader currently assumes exported symbol names are unique. Do
> >> you have a concrete use case? If there is a strong need for this, I
> >> don't think it'd be too hard to implement.
> >
> >I think what would prevent this from working in general is that having
> >two modules with the same exported symbol in different namespaces
> >won't link if you try to build both modules into the kernel itself.
> >
> > Arnd
>
> Ah yeah, you are right. I only tried building an identically named
> exported symbol in a module and in the kernel, and there I got away
> with a modpost warning. But this breaks when building the module into
> the kernel, so I guess this is out of the question.
>
> Thanks,
>
> Jessica
>
The cover letter starts with
"As of Linux 5.3-rc7, there are 31207 [1] exported symbols in the kernel".
Whether or not we apply this patch set,
we will have to carefully maintain them
so that 31207 symbols are unique, anyway.
(And, we can do this with allmodconfig + modpost)
So, what is the point of the namespace,
where it does not loosen the scope of uniqueness?
--
Best Regards
Masahiro Yamada
On Wed, Sep 04, 2019 at 06:53:25PM +0900, Masahiro Yamada wrote:
>On Wed, Sep 4, 2019 at 12:07 AM Matthias Maennich <[email protected]> wrote:
>>
>> A script that uses the '<module>.ns_deps' files generated by modpost to
>> automatically add the required symbol namespace dependencies to each
>> module.
>>
>> Usage:
>> 1) Move some symbols to a namespace with EXPORT_SYMBOL_NS() or define
>> DEFAULT_SYMBOL_NAMESPACE
>> 2) Run 'make' (or 'make modules') and get warnings about modules not
>> importing that namespace.
>> 3) Run 'make nsdeps' to automatically add required import statements
>> to said modules.
>>
>> This makes it easer for subsystem maintainers to introduce and maintain
>> symbol namespaces into their codebase.
>>
>> Co-developed-by: Martijn Coenen <[email protected]>
>> Signed-off-by: Martijn Coenen <[email protected]>
>> Acked-by: Julia Lawall <[email protected]>
>> Reviewed-by: Greg Kroah-Hartman <[email protected]>
>> Signed-off-by: Matthias Maennich <[email protected]>
>
>
>Without any correct dependency,
>this does not work.
You are right, 'nsdeps' needs to depend on 'modules' to make that work.
I will fix that in the next version.
>$ make clean; make nsdeps
>cat: modules.order: No such file or directory
>cat: ./modules.order: No such file or directory
>
>
>I do not see any point in the Makefile changes.
As of Linux 5.3-rc7, there are 31207 [1] exported symbols in the kernel.
That is a growth of roughly 1000 symbols since 4.17 (30206 [2]). There
seems to be some consensus amongst kernel devs that the export surface
is too large, and hard to reason about.
Generally, these symbols fall in one of these categories:
1) Symbols actually meant for drivers
2) Symbols that are only exported because functionality is split over
multiple modules, yet they really shouldn't be used by modules outside
of their own subsystem
3) Symbols really only meant for in-tree use
When module developers try to upstream their code, it regularly turns
out that they are using exported symbols that they really shouldn't be
using. This problem is even bigger for drivers that are currently
out-of-tree, which may be using many symbols that they shouldn't be
using, and that break when those symbols are removed or modified.
This patch allows subsystem maintainers to partition their exported
symbols into separate namespaces, and module authors to import such
namespaces only when needed.
This allows subsystem maintainers to more easily limit availability of
these namespaced symbols to other parts of the kernel. It can also be
used to partition the set of exported symbols for documentation
purposes; for example, a set of symbols that is really only used for
debugging could be in a "SUBSYSTEM_DEBUG" namespace.
I continued the work mainly done by Martijn Coenen.
Changes in v2:
- Rather than adding and evaluating separate sections __knsimport_NS,
use modinfo tags to declare the namespaces a module introduces.
Adjust modpost and the module loader accordingly.
- Also add support for reading multiple modinfo values for the same tag
to allow list-like access to modinfo tags.
- The macros in export.h have been cleaned up to avoid redundancy in the
macro parameters (ns, nspost, nspost2).
- The introduction of relative references in the ksymtab entries caused
a rework of the macros to accommodate that configuration as well.
- Alignment of kernel_symbol in the ksymtab needed to be fixed to allow
growing the kernel_symbol struct.
- Modpost does now also append the namespace suffix to the symbol
entries in Module.symvers.
- The configuration option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS allows
relaxing the enforcement of properly declared namespace imports at
module loading time.
- Symbols can be collectively exported into a namespace by defining
DEFAULT_SYMBOL_NAMESPACE in the corresponding Makefile.
- The requirement for a very recent coccinelle spatch has been lifted by
simplifying the script.
- nsdeps does now ensures MODULE_IMPORT_NS statements are sorted when
patching the module source files.
- Some minor bugs have been addressed in nsdeps to allow it to work with
modules that have more than one source file.
- The RFC for the usb-storage symbols has been simplified by using
DEFAULT_SYMBOL_NAMESPACE=USB_STORAGE rather than explicitly exporting
each and every symbol into that new namespace.
Changes in v3:
- Reword the documentation for the
MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS option for clarification.
- Fix printed required version of spatch in coccinelle script.
- Adopt kbuild changes for modpost: .mod files are no longer generated
in .tmp_versions. Similarely, generate the .ns_deps files in the tree
along with the .mod files. Also, nsdeps now uses modules.order as
source for the list modules to consider.
- Add an RFC patch to introduce the namespace WATCHDOG_CORE for symbols
exported in watchdog_core.c.
Changes in v4:
- scripts/nsdeps:
- exit on first error
- support out-of-tree builds O=...
- scripts/export_report.pl: update for new Module.symvers format
- scripts/mod/modpost: make the namespace a separate field when
exporting to Module.symvers (rather than symbol.NS)
- include/linux/export.h: fixed style nits
- kernel/module.c: ensure namespaces are imported before taking a
reference to the owner module
- Documentation: document the Symbol Namespace feature and update
references to Module.symvers and EXPORT_SYMBOL*
Changes in v5:
- Makefile: let 'nsdeps' depend on 'modules' to allow
`make clean; make nsdeps` to work
- scripts/nsdeps: drop 'exit on first error' again as it just makes more
problems than it solves
- drop the watchdog RFC patch for now
This patch series was developed against v5.3-rc7.
[1] git grep "^EXPORT_SYMBOL\w*(" v5.3-rc7 | wc -l
[2] git grep "^EXPORT_SYMBOL\w*(" v4.17 | wc -l
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Matthias Maennich (11):
module: support reading multiple values per modinfo tag
export: explicitly align struct kernel_symbol
module: add support for symbol namespaces.
modpost: add support for symbol namespaces
module: add config option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
export: allow definition default namespaces in Makefiles or sources
modpost: add support for generating namespace dependencies
scripts: Coccinelle script for namespace dependencies.
docs: Add documentation for Symbol Namespaces
usb-storage: remove single-use define for debugging
usb-storage: export symbols in USB_STORAGE namespace
.gitignore | 1 +
Documentation/kbuild/modules.rst | 7 +-
Documentation/kbuild/namespaces.rst | 154 ++++++++++++++++++++
Documentation/kernel-hacking/hacking.rst | 18 +++
MAINTAINERS | 5 +
Makefile | 14 +-
arch/m68k/include/asm/export.h | 1 -
drivers/usb/storage/Makefile | 2 +
drivers/usb/storage/alauda.c | 1 +
drivers/usb/storage/cypress_atacb.c | 1 +
drivers/usb/storage/datafab.c | 1 +
drivers/usb/storage/debug.h | 2 -
drivers/usb/storage/ene_ub6250.c | 1 +
drivers/usb/storage/freecom.c | 1 +
drivers/usb/storage/isd200.c | 1 +
drivers/usb/storage/jumpshot.c | 1 +
drivers/usb/storage/karma.c | 1 +
drivers/usb/storage/onetouch.c | 1 +
drivers/usb/storage/realtek_cr.c | 1 +
drivers/usb/storage/scsiglue.c | 2 +-
drivers/usb/storage/sddr09.c | 1 +
drivers/usb/storage/sddr55.c | 1 +
drivers/usb/storage/shuttle_usbat.c | 1 +
drivers/usb/storage/uas.c | 1 +
include/asm-generic/export.h | 14 +-
include/linux/export.h | 98 +++++++++++--
include/linux/module.h | 2 +
init/Kconfig | 13 ++
kernel/module.c | 67 ++++++++-
scripts/Makefile.modpost | 4 +-
scripts/coccinelle/misc/add_namespace.cocci | 23 +++
scripts/export_report.pl | 2 +-
scripts/mod/modpost.c | 150 ++++++++++++++++---
scripts/mod/modpost.h | 9 ++
scripts/nsdeps | 58 ++++++++
35 files changed, 608 insertions(+), 52 deletions(-)
create mode 100644 Documentation/kbuild/namespaces.rst
create mode 100644 scripts/coccinelle/misc/add_namespace.cocci
create mode 100644 scripts/nsdeps
--
2.23.0.187.g17f5b7556c-goog
The EXPORT_SYMBOL_NS() and EXPORT_SYMBOL_NS_GPL() macros can be used to
export a symbol to a specific namespace. There are no _GPL_FUTURE and
_UNUSED variants because these are currently unused, and I'm not sure
they are necessary.
I didn't add EXPORT_SYMBOL_NS() for ASM exports; this patch sets the
namespace of ASM exports to NULL by default. In case of relative
references, it will be relocatable to NULL. If there's a need, this
should be pretty easy to add.
A module that wants to use a symbol exported to a namespace must add a
MODULE_IMPORT_NS() statement to their module code; otherwise, modpost
will complain when building the module, and the kernel module loader
will emit an error and fail when loading the module.
MODULE_IMPORT_NS() adds a modinfo tag 'import_ns' to the module. That
tag can be observed by the modinfo command, modpost and kernel/module.c
at the time of loading the module.
The ELF symbols are renamed to include the namespace with an asm label;
for example, symbol 'usb_stor_suspend' in namespace USB_STORAGE becomes
'usb_stor_suspend.USB_STORAGE'. This allows modpost to do namespace
checking, without having to go through all the effort of parsing ELF and
relocation records just to get to the struct kernel_symbols.
On x86_64 I saw no difference in binary size (compression), but at
runtime this will require a word of memory per export to hold the
namespace. An alternative could be to store namespaced symbols in their
own section and use a separate 'struct namespaced_kernel_symbol' for
that section, at the cost of making the module loader more complex.
Co-developed-by: Martijn Coenen <[email protected]>
Signed-off-by: Martijn Coenen <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Matthias Maennich <[email protected]>
---
include/asm-generic/export.h | 6 +--
include/linux/export.h | 91 +++++++++++++++++++++++++++++-------
include/linux/module.h | 2 +
kernel/module.c | 43 +++++++++++++++++
4 files changed, 123 insertions(+), 19 deletions(-)
diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h
index 63f54907317b..e2b5d0f569d3 100644
--- a/include/asm-generic/export.h
+++ b/include/asm-generic/export.h
@@ -17,11 +17,11 @@
.macro __put, val, name
#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
- .long \val - ., \name - .
+ .long \val - ., \name - ., 0 - .
#elif defined(CONFIG_64BIT)
- .quad \val, \name
+ .quad \val, \name, 0
#else
- .long \val, \name
+ .long \val, \name, 0
#endif
.endm
diff --git a/include/linux/export.h b/include/linux/export.h
index 28a4d2150689..d59461e71478 100644
--- a/include/linux/export.h
+++ b/include/linux/export.h
@@ -20,6 +20,8 @@ extern struct module __this_module;
#ifdef CONFIG_MODULES
+#define NS_SEPARATOR "."
+
#if defined(__KERNEL__) && !defined(__GENKSYMS__)
#ifdef CONFIG_MODVERSIONS
/* Mark the CRC weak since genksyms apparently decides not to
@@ -29,13 +31,13 @@ extern struct module __this_module;
asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \
" .weak __crc_" #sym " \n" \
" .long __crc_" #sym " - . \n" \
- " .previous \n");
+ " .previous \n")
#else
#define __CRC_SYMBOL(sym, sec) \
asm(" .section \"___kcrctab" sec "+" #sym "\", \"a\" \n" \
" .weak __crc_" #sym " \n" \
" .long __crc_" #sym " \n" \
- " .previous \n");
+ " .previous \n")
#endif
#else
#define __CRC_SYMBOL(sym, sec)
@@ -49,6 +51,16 @@ extern struct module __this_module;
* absolute relocations that require runtime processing on relocatable
* kernels.
*/
+#define __KSYMTAB_ENTRY_NS(sym, sec, ns) \
+ __ADDRESSABLE(sym) \
+ asm(" .section \"___ksymtab" sec "+" #sym "\", \"a\" \n" \
+ " .balign 4 \n" \
+ "__ksymtab_" #sym NS_SEPARATOR #ns ": \n" \
+ " .long " #sym "- . \n" \
+ " .long __kstrtab_" #sym "- . \n" \
+ " .long __kstrtab_ns_" #sym "- . \n" \
+ " .previous \n")
+
#define __KSYMTAB_ENTRY(sym, sec) \
__ADDRESSABLE(sym) \
asm(" .section \"___ksymtab" sec "+" #sym "\", \"a\" \n" \
@@ -56,32 +68,53 @@ extern struct module __this_module;
"__ksymtab_" #sym ": \n" \
" .long " #sym "- . \n" \
" .long __kstrtab_" #sym "- . \n" \
+ " .long 0 - . \n" \
" .previous \n")
struct kernel_symbol {
int value_offset;
int name_offset;
+ int namespace_offset;
};
#else
+#define __KSYMTAB_ENTRY_NS(sym, sec, ns) \
+ static const struct kernel_symbol __ksymtab_##sym##__##ns \
+ asm("__ksymtab_" #sym NS_SEPARATOR #ns) \
+ __attribute__((section("___ksymtab" sec "+" #sym), used)) \
+ __aligned(sizeof(void *)) \
+ = { (unsigned long)&sym, __kstrtab_##sym, __kstrtab_ns_##sym }
+
#define __KSYMTAB_ENTRY(sym, sec) \
static const struct kernel_symbol __ksymtab_##sym \
+ asm("__ksymtab_" #sym) \
__attribute__((section("___ksymtab" sec "+" #sym), used)) \
__aligned(sizeof(void *)) \
- = { (unsigned long)&sym, __kstrtab_##sym }
+ = { (unsigned long)&sym, __kstrtab_##sym, NULL }
struct kernel_symbol {
unsigned long value;
const char *name;
+ const char *namespace;
};
#endif
-/* For every exported symbol, place a struct in the __ksymtab section */
-#define ___EXPORT_SYMBOL(sym, sec) \
+#define ___export_symbol_common(sym, sec) \
extern typeof(sym) sym; \
- __CRC_SYMBOL(sym, sec) \
+ __CRC_SYMBOL(sym, sec); \
static const char __kstrtab_##sym[] \
__attribute__((section("__ksymtab_strings"), used, aligned(1))) \
- = #sym; \
+ = #sym \
+
+/* For every exported symbol, place a struct in the __ksymtab section */
+#define ___EXPORT_SYMBOL_NS(sym, sec, ns) \
+ ___export_symbol_common(sym, sec); \
+ static const char __kstrtab_ns_##sym[] \
+ __attribute__((section("__ksymtab_strings"), used, aligned(1))) \
+ = #ns; \
+ __KSYMTAB_ENTRY_NS(sym, sec, ns)
+
+#define ___EXPORT_SYMBOL(sym, sec) \
+ ___export_symbol_common(sym, sec); \
__KSYMTAB_ENTRY(sym, sec)
#if defined(__DISABLE_EXPORTS)
@@ -91,6 +124,7 @@ struct kernel_symbol {
* be reused in other execution contexts such as the UEFI stub or the
* decompressor.
*/
+#define __EXPORT_SYMBOL_NS(sym, sec, ns)
#define __EXPORT_SYMBOL(sym, sec)
#elif defined(CONFIG_TRIM_UNUSED_KSYMS)
@@ -117,18 +151,26 @@ struct kernel_symbol {
#define __cond_export_sym_1(sym, sec) ___EXPORT_SYMBOL(sym, sec)
#define __cond_export_sym_0(sym, sec) /* nothing */
+#define __EXPORT_SYMBOL_NS(sym, sec, ns) \
+ __ksym_marker(sym); \
+ __cond_export_ns_sym(sym, sec, ns, __is_defined(__KSYM_##sym))
+#define __cond_export_ns_sym(sym, sec, ns, conf) \
+ ___cond_export_ns_sym(sym, sec, ns, conf)
+#define ___cond_export_ns_sym(sym, sec, ns, enabled) \
+ __cond_export_ns_sym_##enabled(sym, sec, ns)
+#define __cond_export_ns_sym_1(sym, sec, ns) ___EXPORT_SYMBOL_NS(sym, sec, ns)
+#define __cond_export_ns_sym_0(sym, sec, ns) /* nothing */
+
#else
+#define __EXPORT_SYMBOL_NS ___EXPORT_SYMBOL_NS
#define __EXPORT_SYMBOL ___EXPORT_SYMBOL
#endif
-#define EXPORT_SYMBOL(sym) \
- __EXPORT_SYMBOL(sym, "")
-
-#define EXPORT_SYMBOL_GPL(sym) \
- __EXPORT_SYMBOL(sym, "_gpl")
-
-#define EXPORT_SYMBOL_GPL_FUTURE(sym) \
- __EXPORT_SYMBOL(sym, "_gpl_future")
+#define EXPORT_SYMBOL(sym) __EXPORT_SYMBOL(sym, "")
+#define EXPORT_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_gpl")
+#define EXPORT_SYMBOL_GPL_FUTURE(sym) __EXPORT_SYMBOL(sym, "_gpl_future")
+#define EXPORT_SYMBOL_NS(sym, ns) __EXPORT_SYMBOL_NS(sym, "", ns)
+#define EXPORT_SYMBOL_NS_GPL(sym, ns) __EXPORT_SYMBOL_NS(sym, "_gpl", ns)
#ifdef CONFIG_UNUSED_SYMBOLS
#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused")
@@ -138,11 +180,28 @@ struct kernel_symbol {
#define EXPORT_UNUSED_SYMBOL_GPL(sym)
#endif
-#endif /* __GENKSYMS__ */
+#endif /* __KERNEL__ && !__GENKSYMS__ */
+
+#if defined(__GENKSYMS__)
+/*
+ * When we're running genksyms, ignore the namespace and make the _NS
+ * variants look like the normal ones. There are two reasons for this:
+ * 1) In the normal definition of EXPORT_SYMBOL_NS, the 'ns' macro
+ * argument is itself not expanded because it's always tokenized or
+ * concatenated; but when running genksyms, a blank definition of the
+ * macro does allow the argument to be expanded; if a namespace
+ * happens to collide with a #define, this can cause issues.
+ * 2) There's no need to modify genksyms to deal with the _NS variants
+ */
+#define EXPORT_SYMBOL_NS(sym, ns) EXPORT_SYMBOL(sym)
+#define EXPORT_SYMBOL_NS_GPL(sym, ns) EXPORT_SYMBOL_GPL(sym)
+#endif
#else /* !CONFIG_MODULES... */
#define EXPORT_SYMBOL(sym)
+#define EXPORT_SYMBOL_NS(sym, ns)
+#define EXPORT_SYMBOL_NS_GPL(sym, ns)
#define EXPORT_SYMBOL_GPL(sym)
#define EXPORT_SYMBOL_GPL_FUTURE(sym)
#define EXPORT_UNUSED_SYMBOL(sym)
diff --git a/include/linux/module.h b/include/linux/module.h
index 1455812dd325..b3611e749f72 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -280,6 +280,8 @@ struct notifier_block;
#ifdef CONFIG_MODULES
+#define MODULE_IMPORT_NS(ns) MODULE_INFO(import_ns, #ns)
+
extern int modules_disabled; /* for sysctl */
/* Get/put a kernel symbol (calls must be symmetric) */
void *__symbol_get(const char *symbol);
diff --git a/kernel/module.c b/kernel/module.c
index 3ee507c0a92f..6bb9b938f9c7 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -544,6 +544,15 @@ static const char *kernel_symbol_name(const struct kernel_symbol *sym)
#endif
}
+static const char *kernel_symbol_namespace(const struct kernel_symbol *sym)
+{
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+ return offset_to_ptr(&sym->namespace_offset);
+#else
+ return sym->namespace;
+#endif
+}
+
static int cmp_name(const void *va, const void *vb)
{
const char *a;
@@ -1379,6 +1388,34 @@ static inline int same_magic(const char *amagic, const char *bmagic,
}
#endif /* CONFIG_MODVERSIONS */
+static char *get_modinfo(const struct load_info *info, const char *tag);
+static char *get_next_modinfo(const struct load_info *info, const char *tag,
+ char *prev);
+
+static int verify_namespace_is_imported(const struct load_info *info,
+ const struct kernel_symbol *sym,
+ struct module *mod)
+{
+ const char *namespace;
+ char *imported_namespace;
+
+ namespace = kernel_symbol_namespace(sym);
+ if (namespace) {
+ imported_namespace = get_modinfo(info, "import_ns");
+ while (imported_namespace) {
+ if (strcmp(namespace, imported_namespace) == 0)
+ return 0;
+ imported_namespace = get_next_modinfo(
+ info, "import_ns", imported_namespace);
+ }
+ pr_err("%s: module uses symbol (%s) from namespace %s, but does not import it.\n",
+ mod->name, kernel_symbol_name(sym), namespace);
+ return -EINVAL;
+ }
+ return 0;
+}
+
+
/* Resolve a symbol for this module. I.e. if we find one, record usage. */
static const struct kernel_symbol *resolve_symbol(struct module *mod,
const struct load_info *info,
@@ -1407,6 +1444,12 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
goto getname;
}
+ err = verify_namespace_is_imported(info, sym, mod);
+ if (err) {
+ sym = ERR_PTR(err);
+ goto getname;
+ }
+
err = ref_module(mod, owner);
if (err) {
sym = ERR_PTR(err);
--
2.23.0.187.g17f5b7556c-goog
+++ Matthias Maennich [06/09/19 11:32 +0100]:
>As of Linux 5.3-rc7, there are 31207 [1] exported symbols in the kernel.
>That is a growth of roughly 1000 symbols since 4.17 (30206 [2]). There
>seems to be some consensus amongst kernel devs that the export surface
>is too large, and hard to reason about.
>
>Generally, these symbols fall in one of these categories:
>1) Symbols actually meant for drivers
>2) Symbols that are only exported because functionality is split over
> multiple modules, yet they really shouldn't be used by modules outside
> of their own subsystem
>3) Symbols really only meant for in-tree use
>
>When module developers try to upstream their code, it regularly turns
>out that they are using exported symbols that they really shouldn't be
>using. This problem is even bigger for drivers that are currently
>out-of-tree, which may be using many symbols that they shouldn't be
>using, and that break when those symbols are removed or modified.
>
>This patch allows subsystem maintainers to partition their exported
>symbols into separate namespaces, and module authors to import such
>namespaces only when needed.
>
>This allows subsystem maintainers to more easily limit availability of
>these namespaced symbols to other parts of the kernel. It can also be
>used to partition the set of exported symbols for documentation
>purposes; for example, a set of symbols that is really only used for
>debugging could be in a "SUBSYSTEM_DEBUG" namespace.
>
>I continued the work mainly done by Martijn Coenen.
>
>Changes in v2:
>- Rather than adding and evaluating separate sections __knsimport_NS,
> use modinfo tags to declare the namespaces a module introduces.
> Adjust modpost and the module loader accordingly.
>- Also add support for reading multiple modinfo values for the same tag
> to allow list-like access to modinfo tags.
>- The macros in export.h have been cleaned up to avoid redundancy in the
> macro parameters (ns, nspost, nspost2).
>- The introduction of relative references in the ksymtab entries caused
> a rework of the macros to accommodate that configuration as well.
>- Alignment of kernel_symbol in the ksymtab needed to be fixed to allow
> growing the kernel_symbol struct.
>- Modpost does now also append the namespace suffix to the symbol
> entries in Module.symvers.
>- The configuration option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS allows
> relaxing the enforcement of properly declared namespace imports at
> module loading time.
>- Symbols can be collectively exported into a namespace by defining
> DEFAULT_SYMBOL_NAMESPACE in the corresponding Makefile.
>- The requirement for a very recent coccinelle spatch has been lifted by
> simplifying the script.
>- nsdeps does now ensures MODULE_IMPORT_NS statements are sorted when
> patching the module source files.
>- Some minor bugs have been addressed in nsdeps to allow it to work with
> modules that have more than one source file.
>- The RFC for the usb-storage symbols has been simplified by using
> DEFAULT_SYMBOL_NAMESPACE=USB_STORAGE rather than explicitly exporting
> each and every symbol into that new namespace.
>
>Changes in v3:
>- Reword the documentation for the
> MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS option for clarification.
>- Fix printed required version of spatch in coccinelle script.
>- Adopt kbuild changes for modpost: .mod files are no longer generated
> in .tmp_versions. Similarely, generate the .ns_deps files in the tree
> along with the .mod files. Also, nsdeps now uses modules.order as
> source for the list modules to consider.
>- Add an RFC patch to introduce the namespace WATCHDOG_CORE for symbols
> exported in watchdog_core.c.
>
>Changes in v4:
>- scripts/nsdeps:
> - exit on first error
> - support out-of-tree builds O=...
>- scripts/export_report.pl: update for new Module.symvers format
>- scripts/mod/modpost: make the namespace a separate field when
> exporting to Module.symvers (rather than symbol.NS)
>- include/linux/export.h: fixed style nits
>- kernel/module.c: ensure namespaces are imported before taking a
> reference to the owner module
>- Documentation: document the Symbol Namespace feature and update
> references to Module.symvers and EXPORT_SYMBOL*
>
>Changes in v5:
>- Makefile: let 'nsdeps' depend on 'modules' to allow
> `make clean; make nsdeps` to work
>- scripts/nsdeps: drop 'exit on first error' again as it just makes more
> problems than it solves
>- drop the watchdog RFC patch for now
>
>This patch series was developed against v5.3-rc7.
Great work Matthias!
I think this patchset is shaping up nicely. As the merge window is
coming up soon, I'd like to queue this up in modules-next by the end
of today to allow for some testing and "soak" time in linux-next. If
there are any more complaints, please speak up.
Thanks!
Jessica