Here's a patch which adds module symbol versioning to 2.5. The old
implementation had been broken with rusty's module rewrite and been
disabled in the kernel config.
The idea behind the patch is the same as in the old implementation, i.e.
add checksums to exported symbols which change as the ABI changes. Modules
also record the version checksums of the ABI they are built against. When
loading a module into the kernel, those two checksums (per symbol) are
checked against each other to make sure that the ABIs are compatible.
The implementation is basically completely different from the old code
(which was well-known for "do make mrproper when something goes wrong"),
the idea used partially dates back to discussions on linux-kbuild/Keith
Owens/Rusty Russell, and the current code is based in part on a patch by
rusty.
A kernel built with CONFIG_MODVERSIONING will continue to work fine with
unpatched module-init-tools, however, forcing the load of a module
with mismatched symbol versions will need a small patch to
module-init-tools.
Comments, testing or other feedback are much appreciated ;)
--Kai
Against 2.5.59
(Merging changesets omitted for clarity)
-----------------------------------------------------------------------------
[email protected], 2003-01-17 10:26:43-06:00, [email protected]
kbuild: Fix __start_SECTION, __stop_SECTION
In a discussion with Sam Ravnborg, the following problem became apparent:
Most vmlinux.lds.S (but the ARM ones) used the following construct:
__start___ksymtab = .;
__ksymtab : AT(ADDR(__ksymtab) - LOAD_OFFSET) {
*(__ksymtab)
}
__stop___ksymtab = .;
However, the link will align the beginning of the section __ksymtab
according to the requirements for the input sections. If '.' (current
location counter) wasn't sufficiently aligned before, it's possible
that __ksymtab actually starts at an address after the one
__start___ksymtab points to, which will confuse the users of
__start___ksymtab badly. The fix is to follow what the ARM Makefiles
did for this case, ie
__ksymtab : AT(ADDR(__ksymtab) - LOAD_OFFSET) {
__start___ksymtab = .;
*(__ksymtab)
__stop___ksymtab = .;
}
----------------------------------------------------------------------------
vmlinux.lds.h | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)
-----------------------------------------------------------------------------
[email protected], 2003-01-24 13:26:21-06:00, [email protected]
kbuild: Remove -DEXPORT_SYMTAB switch
rusty's module rewrite removed the reference to EXPORT_SYMTAB
from linux/module.h, and it's not used anywhere else, either.
----------------------------------------------------------------------------
Makefile | 4 ----
scripts/Makefile.build | 5 -----
scripts/Makefile.lib | 2 +-
3 files changed, 1 insertion(+), 10 deletions(-)
-----------------------------------------------------------------------------
[email protected], 2003-01-24 13:42:18-06:00, [email protected]
kbuild: Remove obsolete CONFIG_MODVERSIONS cruft
Though the CONFIG_MODVERSIONS option was removed with rusty's module
rewrite and the associated code broken, a lot of that code was still
living on here and there. Now it's gone for good.
----------------------------------------------------------------------------
Makefile | 65 ++------------------------
scripts/Makefile.lib | 14 -----
scripts/Makefile.modver | 118 ------------------------------------------------
3 files changed, 8 insertions(+), 189 deletions(-)
-----------------------------------------------------------------------------
[email protected], 2003-01-24 14:27:06-06:00, [email protected]
kbuild: Add CONFIG_MODVERSIONING and __kcrctab
This patch adds the new config option CONFIG_MODVERSIONING which will
be the new way of checking for ABI changes between kernel and module
code.
This and the following patches are in part based on an initial
implementation by Rusty Russell and I believe some of the ideas go back
to discussions on linux-kbuild, Keith Owens and Rusty.
though I'm not sure I think credit for the basic idea of
storing version info in sections goes to Keith Owens and Rusty.
o Rename __gpl_ksymtab to __ksymtab_gpl since that looks more consistent
and appending _gpl instead of putting it into the middle simplifies
sharing code for EXPORT_SYMBOL() and EXPORT_SYMBOL_GPL()
o Add CONFIG_MODVERSIONING
o If CONFIG_MODVERSIONING is set, add a section __kcrctab{,_gpl}, which
contains the ABI checksums for the exported symbols listed in
__ksymtab{,_crc} Since we don't know the checksums yet at compilation
time, just make them an unresolved symbol which gets filled in by the
linker later.
----------------------------------------------------------------------------
include/asm-generic/vmlinux.lds.h | 22 ++++++++++++++++++----
include/linux/module.h | 31 +++++++++++++++++++++----------
init/Kconfig | 13 +++++++++++++
kernel/module.c | 21 +++++++++++----------
scripts/per-cpu-check.awk | 2 +-
5 files changed, 64 insertions(+), 25 deletions(-)
-----------------------------------------------------------------------------
[email protected], 2003-01-24 21:45:27-06:00, [email protected]
kbuild: Generate versions for exported symbols
Up to now, we had a way to store the checksums associated with the
exported symbols, but they were not filled in yet. This is done
with this patch, using the linker to actually do that for us.
The comment added with this patch explains what magic exactly is going
on.
----------------------------------------------------------------------------
include/linux/module.h | 16 ++++++++++++--
scripts/Makefile.build | 53 +++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 67 insertions(+), 2 deletions(-)
-----------------------------------------------------------------------------
[email protected], 2003-01-24 21:47:14-06:00, [email protected]
kbuild/modules: Check __vermagic for validity
modprobe --force allows to load modules without a matching version
magic string. This invalidation is done by clearing the SHF_ALLOC
flag, so check it in the kernel. Also, clear the SHF_ALLOC flag
unconditionally, since we don't need to store the __vermagic section
in the kernel, it's only checked once at load time.
----------------------------------------------------------------------------
module.c | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)
-----------------------------------------------------------------------------
[email protected], 2003-01-24 21:48:27-06:00, [email protected]
kbuild/modules: Don't save the license string
Again, the license string is only used at load time, so no need
to store it permanently in kernel memory.
----------------------------------------------------------------------------
module.c | 1 +
1 files changed, 1 insertion(+)
-----------------------------------------------------------------------------
[email protected], 2003-01-24 21:49:33-06:00, [email protected]
kbuild/modules: Track versions of exported symbols
Store the information on the checksum alongside the rest of the
information on exported symbols. To actually use them, we need
something to check them against first, though ;)
Also, fix some conditional debug code to actually compile.
----------------------------------------------------------------------------
include/linux/module.h | 1 +
kernel/module.c | 28 ++++++++++++++++++++++++----
2 files changed, 25 insertions(+), 4 deletions(-)
-----------------------------------------------------------------------------
[email protected], 2003-01-24 21:51:36-06:00, [email protected]
kbuild: Always link module (.ko) from associated (.o)
For extracting the versions and finding the unresolved symbols, we
need multi-part modules to be linked together already, so this
patch separates the building of the modules as a .o file from generating
the .ko in the next step.
----------------------------------------------------------------------------
Makefile.build | 32 +++++++++++++++++++-------------
1 files changed, 19 insertions(+), 13 deletions(-)
-----------------------------------------------------------------------------
[email protected], 2003-01-24 21:52:47-06:00, [email protected]
kbuild: Don't build final .ko yet when descending with CONFIG_MODVERSIONING
With CONFIG_MODVERSIONING, we need to record the versions of the unresolved
symbols in the final <module>.ko, which we only know after we finished
the descending build. So we only build <module>.o in that case.
Also, keep track of the modules we built, the post-processing step needs
a list of all modules. Keeping track is done by touching
.tmp_versions/path/to/module.ko
----------------------------------------------------------------------------
Makefile | 24 ++++++++++++++++++++++++
scripts/Makefile.build | 25 ++++++++++++++++++++++++-
2 files changed, 48 insertions(+), 1 deletion(-)
-----------------------------------------------------------------------------
[email protected], 2003-01-24 21:54:04-06:00, [email protected]
kbuild/modules: Record versions for unresolved symbols
In the case of CONFIG_MODVERSIONING, the build step will only
generate preliminary <module>.o objects, and an additional
postprocessing step is necessary to record the versions of the unresolved
symbols and add them into the final <module>.ko
The version information for unresolved symbols is again recorded into
a special section, "__versions", which contains an array of symbol
name strings and checksum (struct modversion_info). Size is here not
an issue, since this section will not be stored permanently in kernel
memory.
Makefile.modver takes care of the following steps:
o Collect the version information for all exported symbols from vmlinux
and all modules which export symbols.
o For each module, generate a C file which contains the modversion
information for all unresolved symbols in that module.
o For each module, compile that C file to an object file
o Finally, link the <module>.ko using the preliminary <module.o> + the
version information above.
The first two steps are currently done by not very efficient scripting,
so there's room for performance improvement using some helper C code.
----------------------------------------------------------------------------
Makefile | 15 ++++++--
include/linux/module.h | 7 +++
scripts/Makefile.modver | 89 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 108 insertions(+), 3 deletions(-)
-----------------------------------------------------------------------------
[email protected], 2003-01-24 21:54:53-06:00, [email protected]
kbuild/modules: Return the index of the symbol from __find_symbol()
We'll need that index to find the version checksum for the symbol in
a bit.
----------------------------------------------------------------------------
module.c | 10 +++++++---
1 files changed, 7 insertions(+), 3 deletions(-)
-----------------------------------------------------------------------------
[email protected], 2003-01-24 21:55:37-06:00, [email protected]
kbuild/modules: Check module symbol versions on insmod
Yeah, the final step!
Now that we've got the checksums for the exported symbols and the
checksums of the unresolved symbols for the module we're loading,
let's compare and see.
Again, we allow to load a module which has the version info stripped,
but taint the kernel in that case.
----------------------------------------------------------------------------
module.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-------
1 files changed, 73 insertions(+), 8 deletions(-)
=============================================================================
unified diffs follow for reference
=============================================================================
-----------------------------------------------------------------------------
[email protected], 2003-01-17 10:26:43-06:00, [email protected]
kbuild: Fix __start_SECTION, __stop_SECTION
In a discussion with Sam Ravnborg, the following problem became apparent:
Most vmlinux.lds.S (but the ARM ones) used the following construct:
__start___ksymtab = .;
__ksymtab : AT(ADDR(__ksymtab) - LOAD_OFFSET) {
*(__ksymtab)
}
__stop___ksymtab = .;
However, the link will align the beginning of the section __ksymtab
according to the requirements for the input sections. If '.' (current
location counter) wasn't sufficiently aligned before, it's possible
that __ksymtab actually starts at an address after the one
__start___ksymtab points to, which will confuse the users of
__start___ksymtab badly. The fix is to follow what the ARM Makefiles
did for this case, ie
__ksymtab : AT(ADDR(__ksymtab) - LOAD_OFFSET) {
__start___ksymtab = .;
*(__ksymtab)
__stop___ksymtab = .;
}
---------------------------------------------------------------------------
diff -Nru a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
--- a/include/asm-generic/vmlinux.lds.h Sat Jan 25 12:24:59 2003
+++ b/include/asm-generic/vmlinux.lds.h Sat Jan 25 12:24:59 2003
@@ -13,18 +13,18 @@
} \
\
/* Kernel symbol table: Normal symbols */ \
- __start___ksymtab = .; \
__ksymtab : AT(ADDR(__ksymtab) - LOAD_OFFSET) { \
+ __start___ksymtab = .; \
*(__ksymtab) \
+ __stop___ksymtab = .; \
} \
- __stop___ksymtab = .; \
\
/* Kernel symbol table: GPL-only symbols */ \
- __start___gpl_ksymtab = .; \
__gpl_ksymtab : AT(ADDR(__gpl_ksymtab) - LOAD_OFFSET) { \
+ __start___gpl_ksymtab = .; \
*(__gpl_ksymtab) \
+ __stop___gpl_ksymtab = .; \
} \
- __stop___gpl_ksymtab = .; \
\
/* Kernel symbol table: strings */ \
__ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) { \
-----------------------------------------------------------------------------
[email protected], 2003-01-24 13:26:21-06:00, [email protected]
kbuild: Remove -DEXPORT_SYMTAB switch
rusty's module rewrite removed the reference to EXPORT_SYMTAB
from linux/module.h, and it's not used anywhere else, either.
---------------------------------------------------------------------------
diff -Nru a/Makefile b/Makefile
--- a/Makefile Sat Jan 25 12:25:02 2003
+++ b/Makefile Sat Jan 25 12:25:02 2003
@@ -256,10 +256,6 @@
-include .config.cmd
-ifdef CONFIG_MODULES
-export EXPORT_FLAGS := -DEXPORT_SYMTAB
-endif
-
ifndef CONFIG_FRAME_POINTER
CFLAGS += -fomit-frame-pointer
endif
diff -Nru a/scripts/Makefile.build b/scripts/Makefile.build
--- a/scripts/Makefile.build Sat Jan 25 12:25:02 2003
+++ b/scripts/Makefile.build Sat Jan 25 12:25:02 2003
@@ -69,11 +69,6 @@
$(obj-m) : quiet_modtag := [M]
-$(export-objs) : export_flags := $(EXPORT_FLAGS)
-$(export-objs:.o=.i) : export_flags := $(EXPORT_FLAGS)
-$(export-objs:.o=.s) : export_flags := $(EXPORT_FLAGS)
-$(export-objs:.o=.lst): export_flags := $(EXPORT_FLAGS)
-
# Default for not multi-part modules
modname = $(*F)
diff -Nru a/scripts/Makefile.lib b/scripts/Makefile.lib
--- a/scripts/Makefile.lib Sat Jan 25 12:25:02 2003
+++ b/scripts/Makefile.lib Sat Jan 25 12:25:02 2003
@@ -130,7 +130,7 @@
modname_flags = $(if $(filter 1,$(words $(modname))),-DKBUILD_MODNAME=$(subst $(comma),_,$(subst -,_,$(modname))))
c_flags = -Wp,-MD,$(depfile) $(CFLAGS) $(NOSTDINC_FLAGS) \
$(modkern_cflags) $(EXTRA_CFLAGS) $(CFLAGS_$(*F).o) \
- $(basename_flags) $(modname_flags) $(export_flags)
+ $(basename_flags) $(modname_flags)
a_flags = -Wp,-MD,$(depfile) $(AFLAGS) $(NOSTDINC_FLAGS)\
$(modkern_aflags) $(EXTRA_AFLAGS) $(AFLAGS_$(*F).o)
hostc_flags = -Wp,-MD,$(depfile) $(HOSTCFLAGS) $(HOST_EXTRACFLAGS)\
-----------------------------------------------------------------------------
[email protected], 2003-01-24 13:42:18-06:00, [email protected]
kbuild: Remove obsolete CONFIG_MODVERSIONS cruft
Though the CONFIG_MODVERSIONS option was removed with rusty's module
rewrite and the associated code broken, a lot of that code was still
living on here and there. Now it's gone for good.
---------------------------------------------------------------------------
diff -Nru a/Makefile b/Makefile
--- a/Makefile Sat Jan 25 12:25:04 2003
+++ b/Makefile Sat Jan 25 12:25:04 2003
@@ -380,7 +380,7 @@
# Handle descending into subdirectories listed in $(SUBDIRS)
.PHONY: $(SUBDIRS)
-$(SUBDIRS): .hdepend prepare
+$(SUBDIRS): prepare
$(Q)$(MAKE) $(build)=$@
# Things we need done before we descend to build or make
@@ -471,61 +471,11 @@
) > [email protected]
@$(update-if-changed)
-# Generate module versions
# ---------------------------------------------------------------------------
-# The targets are still named depend / dep for traditional
-# reasons, but the only thing we do here is generating
-# the module version checksums.
-
-.PHONY: depend dep $(patsubst %,_sfdep_%,$(SUBDIRS))
-
-depend dep: .hdepend
-
-# .hdepend is our (misnomed) marker for whether we've
-# generated module versions
-
-make-versions := $(strip $(if $(filter dep depend,$(MAKECMDGOALS)),1) \
- $(if $(wildcard .hdepend),,1))
-
-.hdepend: prepare FORCE
-ifneq ($(make-versions),)
- @$(MAKE) include/linux/modversions.h
- @touch $@
-endif
-
-ifdef CONFIG_MODVERSIONS
-
-# Update modversions.h, but only if it would change.
-
-.PHONY: __rm_tmp_export-objs
-__rm_tmp_export-objs:
- @rm -rf .tmp_export-objs
-
-include/linux/modversions.h: $(patsubst %,_modver_%,$(SUBDIRS))
- @echo -n ' Generating $@'
- @( echo "#ifndef _LINUX_MODVERSIONS_H";\
- echo "#define _LINUX_MODVERSIONS_H"; \
- echo "#include <linux/modsetver.h>"; \
- cd .tmp_export-objs >/dev/null; \
- for f in `find modules -name \*.ver -print | sort`; do \
- echo "#include <linux/$${f}>"; \
- done; \
- echo "#endif"; \
- ) > [email protected]; \
- $(update-if-changed)
-
-.PHONY: $(patsubst %, _modver_%, $(SUBDIRS))
-$(patsubst %, _modver_%, $(SUBDIRS)): __rm_tmp_export-objs
- $(Q)$(MAKE) -f scripts/Makefile.modver obj=$(patsubst _modver_%,%,$@)
-
-else # !CONFIG_MODVERSIONS
-
-.PHONY: include/linux/modversions.h
-
-include/linux/modversions.h:
-
-endif # CONFIG_MODVERSIONS
+.PHONY: depend dep
+depend dep:
+ @echo'*** Warning: make $@ is unnecessary now.'
# ---------------------------------------------------------------------------
# Modules
@@ -534,10 +484,6 @@
# Build modules
-ifdef CONFIG_MODVERSIONS
-MODFLAGS += -include include/linux/modversions.h
-endif
-
.PHONY: modules
modules: $(SUBDIRS)
@@ -570,6 +516,7 @@
.PHONY: $(patsubst %, _modinst_%, $(SUBDIRS))
$(patsubst %, _modinst_%, $(SUBDIRS)) :
$(Q)$(MAKE) -rR -f scripts/Makefile.modinst obj=$(patsubst _modinst_%,%,$@)
+
else # CONFIG_MODULES
# Modules not configured
@@ -620,7 +567,7 @@
rpm: clean spec
find . $(RCS_FIND_IGNORE) \
- \( -size 0 -o -name .depend -o -name .hdepend \) \
+ \( -size 0 -o -name .depend -o -name .hdepend\) \
-type f -print | xargs rm -f
set -e; \
cd $(TOPDIR)/.. ; \
diff -Nru a/scripts/Makefile.lib b/scripts/Makefile.lib
--- a/scripts/Makefile.lib Sat Jan 25 12:25:04 2003
+++ b/scripts/Makefile.lib Sat Jan 25 12:25:04 2003
@@ -34,14 +34,9 @@
subdir-ym := $(sort $(subdir-y) $(subdir-m))
-# export.o is never a composite object, since $(export-objs) has a
-# fixed meaning (== objects which EXPORT_SYMBOL())
-__obj-y = $(filter-out export.o,$(obj-y))
-__obj-m = $(filter-out export.o,$(obj-m))
-
# if $(foo-objs) exists, foo.o is a composite object
-multi-used-y := $(sort $(foreach m,$(__obj-y), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))), $(m))))
-multi-used-m := $(sort $(foreach m,$(__obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))), $(m))))
+multi-used-y := $(sort $(foreach m,$(obj-y), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))), $(m))))
+multi-used-m := $(sort $(foreach m,$(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))), $(m))))
multi-used := $(multi-used-y) $(multi-used-m)
single-used-m := $(sort $(filter-out $(multi-used-m),$(obj-m)))
@@ -59,9 +54,6 @@
real-objs-y := $(foreach m, $(filter-out $(subdir-obj-y), $(obj-y)), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))),$($(m:.o=-objs)) $($(m:.o=-y)),$(m))) $(EXTRA_TARGETS)
real-objs-m := $(foreach m, $(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))),$($(m:.o=-objs)) $($(m:.o=-y)),$(m)))
-# Only build module versions for files which are selected to be built
-export-objs := $(filter $(export-objs),$(real-objs-y) $(real-objs-m))
-
# C code
# Executables compiled from a single .c file
host-csingle := $(foreach m,$(host-progs),$(if $($(m)-objs),,$(m)))
@@ -96,7 +88,6 @@
build-targets := $(addprefix $(obj)/,$(build-targets))
obj-y := $(addprefix $(obj)/,$(obj-y))
obj-m := $(addprefix $(obj)/,$(obj-m))
-export-objs := $(addprefix $(obj)/,$(export-objs))
subdir-obj-y := $(addprefix $(obj)/,$(subdir-obj-y))
real-objs-y := $(addprefix $(obj)/,$(real-objs-y))
real-objs-m := $(addprefix $(obj)/,$(real-objs-m))
@@ -217,7 +208,6 @@
$(filter-out $(cmd_$(1)),$(cmd_$@))\
$(filter-out $(cmd_$@),$(cmd_$(1)))),\
@set -e; \
- mkdir -p $(dir $@); \
$(rule_$(1)))
# If quiet is set, only print short version of command
diff -Nru a/scripts/Makefile.modver b/scripts/Makefile.modver
--- a/scripts/Makefile.modver Sat Jan 25 12:25:04 2003
+++ b/scripts/Makefile.modver Sat Jan 25 12:25:04 2003
@@ -2,121 +2,3 @@
# Module versions
# ===========================================================================
-src := $(obj)
-
-MODVERDIR := include/linux/modules
-
-.PHONY: modver
-modver:
-
-include .config
-
-include $(obj)/Makefile
-
-include scripts/Makefile.lib
-
-# ===========================================================================
-
-ifeq ($(strip $(export-objs)),)
-
-# If we don't export any symbols in this dir, just descend
-# ---------------------------------------------------------------------------
-
-modver: $(subdir-ym)
- @:
-
-else
-
-# This sets version suffixes on exported symbols
-# ---------------------------------------------------------------------------
-
-#
-# Added the SMP separator to stop module accidents between uniprocessor
-# and SMP Intel boxes - AC - from bits by Michael Chastain
-#
-
-ifdef CONFIG_SMP
- genksyms_smp_prefix := -p smp_
-else
- genksyms_smp_prefix :=
-endif
-
-# Don't include modversions.h, we're just about to generate it here.
-
-CFLAGS_MODULE := $(filter-out -include include/linux/modversions.h,$(CFLAGS_MODULE))
-
-$(addprefix $(MODVERDIR)/,$(real-objs-y:.o=.ver)): modkern_cflags := $(CFLAGS_KERNEL)
-$(addprefix $(MODVERDIR)/,$(real-objs-m:.o=.ver)): modkern_cflags := $(CFLAGS_MODULE)
-$(addprefix $(MODVERDIR)/,$(export-objs:.o=.ver)): export_flags := -D__GENKSYMS__
-# Default for not multi-part modules
-modname = $(*F)
-
-$(addprefix $(MODVERDIR)/,$(multi-objs:.o=.ver)) : modname = $(modname-multi)
-
-# Our objects only depend on modversions.h, not on the individual .ver
-# files (fix-dep filters them), so touch modversions.h if any of the .ver
-# files changes
-
-quiet_cmd_cc_ver_c = MKVER include/linux/modules/$*.ver
-cmd_cc_ver_c = $(CPP) $(c_flags) $< | $(GENKSYMS) $(genksyms_smp_prefix) \
- -k $(VERSION).$(PATCHLEVEL).$(SUBLEVEL) > [email protected]
-
-# Okay, let's explain what's happening in rule_make_cc_ver_c:
-# o echo the command
-# o execute the command
-# o If the $(CPP) fails, we won't notice because it's output is piped
-# to $(GENKSYMS) which does not fail. We recognize this case by
-# looking if the generated $(depfile) exists, though.
-# o If the .ver file changed, touch modversions.h, which is our marker
-# of any changed .ver files.
-# o Move command line and deps into their normal .*.cmd place.
-
-define rule_cc_ver_c
- $(if $($(quiet)cmd_cc_ver_c),echo ' $($(quiet)cmd_cc_ver_c)';) \
- $(cmd_cc_ver_c); \
- if [ ! -r $(depfile) ]; then exit 1; fi; \
- scripts/fixdep $(depfile) $@ '$(cmd_cc_ver_c)' > $(@D)/.$(@F).tmp; \
- rm -f $(depfile); \
- if [ ! -r $@ ] || cmp -s $@ [email protected]; then \
- touch include/linux/modversions.h; \
- fi; \
- mv -f [email protected] $@
- mv -f $(@D)/.$(@F).tmp $(@D)/.$(@F).cmd
-endef
-
-targets := $(addprefix $(MODVERDIR)/,$(export-objs:.o=.ver))
-
-$(MODVERDIR)/%.ver: %.c FORCE
- @$(call if_changed_rule,cc_ver_c)
-
-modver: $(targets) $(subdir-ym)
- @mkdir -p $(dir $(addprefix .tmp_export-objs/modules/,$(export-objs:.o=.ver)))
- @touch $(addprefix .tmp_export-objs/modules/,$(export-objs:.o=.ver))
-
-endif # export-objs
-
-# Descending
-# ---------------------------------------------------------------------------
-
-.PHONY: $(subdir-ym)
-$(subdir-ym):
- $(Q)$(MAKE) -f scripts/Makefile.modver obj=$@
-
-# Add FORCE to the prequisites of a target to force it to be always rebuilt.
-# ---------------------------------------------------------------------------
-
-.PHONY: FORCE
-
-FORCE:
-
-# Read all saved command lines and dependencies for the $(targets) we
-# may be building above, using $(if_changed{,_dep}). As an
-# optimization, we don't need to read them if the target does not
-# exist, we will rebuild anyway in that case.
-
-targets := $(wildcard $(sort $(targets)))
-cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
-
-ifneq ($(cmd_files),)
- include $(cmd_files)
-endif
-----------------------------------------------------------------------------
[email protected], 2003-01-24 14:27:06-06:00, [email protected]
kbuild: Add CONFIG_MODVERSIONING and __kcrctab
This patch adds the new config option CONFIG_MODVERSIONING which will
be the new way of checking for ABI changes between kernel and module
code.
This and the following patches are in part based on an initial
implementation by Rusty Russell and I believe some of the ideas go back
to discussions on linux-kbuild, Keith Owens and Rusty.
though I'm not sure I think credit for the basic idea of
storing version info in sections goes to Keith Owens and Rusty.
o Rename __gpl_ksymtab to __ksymtab_gpl since that looks more consistent
and appending _gpl instead of putting it into the middle simplifies
sharing code for EXPORT_SYMBOL() and EXPORT_SYMBOL_GPL()
o Add CONFIG_MODVERSIONING
o If CONFIG_MODVERSIONING is set, add a section __kcrctab{,_gpl}, which
contains the ABI checksums for the exported symbols listed in
__ksymtab{,_crc} Since we don't know the checksums yet at compilation
time, just make them an unresolved symbol which gets filled in by the
linker later.
---------------------------------------------------------------------------
diff -Nru a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
--- a/include/asm-generic/vmlinux.lds.h Sat Jan 25 12:25:07 2003
+++ b/include/asm-generic/vmlinux.lds.h Sat Jan 25 12:25:07 2003
@@ -20,10 +20,24 @@
} \
\
/* Kernel symbol table: GPL-only symbols */ \
- __gpl_ksymtab : AT(ADDR(__gpl_ksymtab) - LOAD_OFFSET) { \
- __start___gpl_ksymtab = .; \
- *(__gpl_ksymtab) \
- __stop___gpl_ksymtab = .; \
+ __ksymtab_gpl : AT(ADDR(__ksymtab_gpl) - LOAD_OFFSET) { \
+ __start___ksymtab_gpl = .; \
+ *(__ksymtab_gpl) \
+ __stop___ksymtab_gpl = .; \
+ } \
+ \
+ /* Kernel symbol table: Normal symbols */ \
+ __kcrctab : AT(ADDR(__kcrctab) - LOAD_OFFSET) { \
+ __start___kcrctab = .; \
+ *(__kcrctab) \
+ __stop___kcrctab = .; \
+ } \
+ \
+ /* Kernel symbol table: GPL-only symbols */ \
+ __kcrctab_gpl : AT(ADDR(__kcrctab_gpl) - LOAD_OFFSET) { \
+ __start___kcrctab_gpl = .; \
+ *(__kcrctab_gpl) \
+ __stop___kcrctab_gpl = .; \
} \
\
/* Kernel symbol table: strings */ \
diff -Nru a/include/linux/module.h b/include/linux/module.h
--- a/include/linux/module.h Sat Jan 25 12:25:07 2003
+++ b/include/linux/module.h Sat Jan 25 12:25:07 2003
@@ -134,29 +134,40 @@
#ifdef CONFIG_MODULES
+
/* Get/put a kernel symbol (calls must be symmetric) */
void *__symbol_get(const char *symbol);
void *__symbol_get_gpl(const char *symbol);
#define symbol_get(x) ((typeof(&x))(__symbol_get(MODULE_SYMBOL_PREFIX #x)))
+#ifdef CONFIG_MODVERSIONING
+/* Mark the CRC weak since genksyms apparently decides not to
+ * generate a checksums for some symbols */
+#define __CRC_SYMBOL(sym, sec) \
+ extern void *__crc_##sym __attribute__((weak)); \
+ static const unsigned long __kcrctab_##sym \
+ __attribute__((section("__kcrctab" sec))) \
+ = (unsigned long) &__crc_##sym;
+#else
+#define __CRC_SYMBOL(sym, sec)
+#endif
+
/* For every exported symbol, place a struct in the __ksymtab section */
-#define EXPORT_SYMBOL(sym) \
+#define __EXPORT_SYMBOL(sym, sec) \
+ __CRC_SYMBOL(sym, sec) \
static const char __kstrtab_##sym[] \
__attribute__((section("__ksymtab_strings"))) \
= MODULE_SYMBOL_PREFIX #sym; \
static const struct kernel_symbol __ksymtab_##sym \
- __attribute__((section("__ksymtab"))) \
+ __attribute__((section("__ksymtab" sec))) \
= { (unsigned long)&sym, __kstrtab_##sym }
-#define EXPORT_SYMBOL_NOVERS(sym) EXPORT_SYMBOL(sym)
+#define EXPORT_SYMBOL(sym) __EXPORT_SYMBOL(sym, "")
+#define EXPORT_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_gpl")
-#define EXPORT_SYMBOL_GPL(sym) \
- static const char __kstrtab_##sym[] \
- __attribute__((section("__ksymtab_strings"))) \
- = MODULE_SYMBOL_PREFIX #sym; \
- static const struct kernel_symbol __ksymtab_##sym \
- __attribute__((section("__gpl_ksymtab"))) \
- = { (unsigned long)&sym, __kstrtab_##sym }
+/* We don't mangle the actual symbol anymore, so no need for
+ * special casing EXPORT_SYMBOL_NOVERS */
+#define EXPORT_SYMBOL_NOVERS(sym) EXPORT_SYMBOL(sym)
struct module_ref
{
diff -Nru a/init/Kconfig b/init/Kconfig
--- a/init/Kconfig Sat Jan 25 12:25:07 2003
+++ b/init/Kconfig Sat Jan 25 12:25:07 2003
@@ -144,6 +144,19 @@
have not been converted to the new module parameter system yet.
If unsure, say Y.
+config MODVERSIONING
+ bool "Module versioning support (EXPERIMENTAL)"
+ depends on MODULES && EXPERIMENTAL
+ help
+ ---help---
+ Usually, you have to use modules compiled with your kernel.
+ Saying Y here makes it sometimes possible to use modules
+ compiled for different kernels, by adding enough information
+ to the modules to (hopefully) spot any changes which would
+ make them incompatible with the kernel you are running. If
+ you say Y here, you will need a copy of genksyms. If
+ unsure, say N.
+
config KMOD
bool "Kernel module loader"
depends on MODULES
diff -Nru a/kernel/module.c b/kernel/module.c
--- a/kernel/module.c Sat Jan 25 12:25:07 2003
+++ b/kernel/module.c Sat Jan 25 12:25:07 2003
@@ -1040,6 +1040,11 @@
/* Exported symbols. */
DEBUGP("EXPORT table in section %u\n", i);
exportindex = i;
+ } else if (strcmp(secstrings+sechdrs[i].sh_name,
+ "__ksymtab_gpl") == 0) {
+ /* Exported symbols. (GPL) */
+ DEBUGP("GPL symbols found in section %u\n", i);
+ gplindex = i;
} else if (strcmp(secstrings+sechdrs[i].sh_name, "__param")
== 0) {
/* Setup parameter info */
@@ -1061,11 +1066,6 @@
DEBUGP("Licence found in section %u\n", i);
licenseindex = i;
} else if (strcmp(secstrings+sechdrs[i].sh_name,
- "__gpl_ksymtab") == 0) {
- /* EXPORT_SYMBOL_GPL() */
- DEBUGP("GPL symbols found in section %u\n", i);
- gplindex = i;
- } else if (strcmp(secstrings+sechdrs[i].sh_name,
"__vermagic") == 0) {
/* Version magic. */
DEBUGP("Version magic found in section %u\n", i);
@@ -1492,8 +1492,8 @@
/* Provided by the linker */
extern const struct kernel_symbol __start___ksymtab[];
extern const struct kernel_symbol __stop___ksymtab[];
-extern const struct kernel_symbol __start___gpl_ksymtab[];
-extern const struct kernel_symbol __stop___gpl_ksymtab[];
+extern const struct kernel_symbol __start___ksymtab_gpl[];
+extern const struct kernel_symbol __stop___ksymtab_gpl[];
static struct kernel_symbol_group kernel_symbols, kernel_gpl_symbols;
@@ -1504,9 +1504,10 @@
kernel_symbols.syms = __start___ksymtab;
kernel_symbols.gplonly = 0;
list_add(&kernel_symbols.list, &symbols);
- kernel_gpl_symbols.num_syms = (__stop___gpl_ksymtab
- - __start___gpl_ksymtab);
- kernel_gpl_symbols.syms = __start___gpl_ksymtab;
+
+ kernel_gpl_symbols.num_syms = (__stop___ksymtab_gpl
+ - __start___ksymtab_gpl);
+ kernel_gpl_symbols.syms = __start___ksymtab_gpl;
kernel_gpl_symbols.gplonly = 1;
list_add(&kernel_gpl_symbols.list, &symbols);
diff -Nru a/scripts/per-cpu-check.awk b/scripts/per-cpu-check.awk
--- a/scripts/per-cpu-check.awk Sat Jan 25 12:25:07 2003
+++ b/scripts/per-cpu-check.awk Sat Jan 25 12:25:07 2003
@@ -6,7 +6,7 @@
IN_PER_CPU=0
}
-/__per_cpu$$/ && ! ( / __ksymtab_/ || / __kstrtab_/ ) {
+/__per_cpu$$/ && ! ( / __ksymtab_/ || / __kstrtab_/ || / __kcrctab_/ ) {
if (!IN_PER_CPU) {
print $$3 " not in per-cpu section" > "/dev/stderr";
FOUND=1;
-----------------------------------------------------------------------------
[email protected], 2003-01-24 21:45:27-06:00, [email protected]
kbuild: Generate versions for exported symbols
Up to now, we had a way to store the checksums associated with the
exported symbols, but they were not filled in yet. This is done
with this patch, using the linker to actually do that for us.
The comment added with this patch explains what magic exactly is going
on.
---------------------------------------------------------------------------
diff -Nru a/include/linux/module.h b/include/linux/module.h
--- a/include/linux/module.h Sat Jan 25 12:25:10 2003
+++ b/include/linux/module.h Sat Jan 25 12:25:10 2003
@@ -140,6 +140,13 @@
void *__symbol_get_gpl(const char *symbol);
#define symbol_get(x) ((typeof(&x))(__symbol_get(MODULE_SYMBOL_PREFIX #x)))
+#ifdef __GENKSYMS__
+
+/* genksyms doesn't handle GPL-only symbols yet */
+#define EXPORT_SYMBOL_GPL EXPORT_SYMBOL
+
+#else
+
#ifdef CONFIG_MODVERSIONING
/* Mark the CRC weak since genksyms apparently decides not to
* generate a checksums for some symbols */
@@ -162,8 +169,13 @@
__attribute__((section("__ksymtab" sec))) \
= { (unsigned long)&sym, __kstrtab_##sym }
-#define EXPORT_SYMBOL(sym) __EXPORT_SYMBOL(sym, "")
-#define EXPORT_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_gpl")
+#define EXPORT_SYMBOL(sym) \
+ __EXPORT_SYMBOL(sym, "")
+
+#define EXPORT_SYMBOL_GPL(sym) \
+ __EXPORT_SYMBOL(sym, "_gpl")
+
+#endif
/* We don't mangle the actual symbol anymore, so no need for
* special casing EXPORT_SYMBOL_NOVERS */
diff -Nru a/scripts/Makefile.build b/scripts/Makefile.build
--- a/scripts/Makefile.build Sat Jan 25 12:25:10 2003
+++ b/scripts/Makefile.build Sat Jan 25 12:25:10 2003
@@ -50,6 +50,55 @@
$(subdir-ym) $(build-targets)
@:
+# Module versioning
+# ---------------------------------------------------------------------------
+
+ifdef CONFIG_MODVERSIONING
+
+# $(call if_changed_rule,vcc_o_c) does essentially the same as the
+# normal $(call if_changed_dep,cc_o_c), i.e. compile an object file
+# from a C file, keeping track of the command line and dependencies.
+#
+# However, actually it does:
+# o compile a .tmp_<file>.o from <file>.c
+# o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does
+# not export symbols, we just rename .tmp_<file>.o to <file>.o and
+# are done.
+# o otherwise, we calculate symbol versions using the good old
+# genksyms on the preprocessed source and postprocess them in a way
+# that they are usable as a linker script
+# o generate <file>.o from .tmp_<file>.o using the linker to
+# replace the unresolved symbols __crc_exported_symbol with
+# the actual value of the checksum generated by genksyms
+
+quiet_cmd_vcc_o_c = CC $(quiet_modtag) $@
+cmd_vcc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
+
+define rule_vcc_o_c
+ $(if $($(quiet)cmd_vcc_o_c),echo ' $($(quiet)cmd_vcc_o_c)';) \
+ $(cmd_vcc_o_c); \
+ \
+ if ! $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \
+ mv $(@D)/.tmp_$(@F) $@; \
+ else \
+ $(CPP) -D__GENKSYMS__ $(c_flags) $< \
+ | $(GENKSYMS) -k $(VERSION).$(PATCHLEVEL).$(SUBLEVEL) \
+ | grep __ver \
+ | sed 's/\#define __ver_\([^ ]*\)[ ]*\([^ ]*\)/__crc_\1 = 0x\2 ;/g' \
+ > $(@D)/.tmp_$(@F:.o=.ver); \
+ \
+ $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \
+ -T $(@D)/.tmp_$(@F:.o=.ver); \
+ rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \
+ fi;
+ \
+ scripts/fixdep $(depfile) $@ '$(cmd_vcc_o_c)' > $(@D)/.$(@F).tmp; \
+ rm -f $(depfile); \
+ mv -f $(@D)/.$(@F).tmp $(@D)/.$(@F).cmd
+endef
+
+endif
+
# Compile C sources (.c)
# ---------------------------------------------------------------------------
@@ -97,7 +146,11 @@
cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
%.o: %.c FORCE
+ifdef CONFIG_MODVERSIONING
+ $(call if_changed_rule,vcc_o_c)
+else
$(call if_changed_dep,cc_o_c)
+endif
quiet_cmd_cc_lst_c = MKLST $@
cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
-----------------------------------------------------------------------------
[email protected], 2003-01-24 21:47:14-06:00, [email protected]
kbuild/modules: Check __vermagic for validity
modprobe --force allows to load modules without a matching version
magic string. This invalidation is done by clearing the SHF_ALLOC
flag, so check it in the kernel. Also, clear the SHF_ALLOC flag
unconditionally, since we don't need to store the __vermagic section
in the kernel, it's only checked once at load time.
---------------------------------------------------------------------------
diff -Nru a/kernel/module.c b/kernel/module.c
--- a/kernel/module.c Sat Jan 25 12:25:12 2003
+++ b/kernel/module.c Sat Jan 25 12:25:12 2003
@@ -1066,10 +1066,12 @@
DEBUGP("Licence found in section %u\n", i);
licenseindex = i;
} else if (strcmp(secstrings+sechdrs[i].sh_name,
- "__vermagic") == 0) {
+ "__vermagic") == 0 &&
+ (sechdrs[i].sh_flags & SHF_ALLOC)) {
/* Version magic. */
DEBUGP("Version magic found in section %u\n", i);
vmagindex = i;
+ sechdrs[i].sh_flags &= ~(unsigned long)SHF_ALLOC;
}
#ifdef CONFIG_KALLSYMS
/* symbol and string tables for decoding later. */
@@ -1090,7 +1092,7 @@
}
mod = (void *)sechdrs[modindex].sh_addr;
- /* This is allowed: modprobe --force will strip it. */
+ /* This is allowed: modprobe --force will invalidate it. */
if (!vmagindex) {
tainted |= TAINT_FORCED_MODULE;
printk(KERN_WARNING "%s: no version magic, tainting kernel.\n",
-----------------------------------------------------------------------------
[email protected], 2003-01-24 21:48:27-06:00, [email protected]
kbuild/modules: Don't save the license string
Again, the license string is only used at load time, so no need
to store it permanently in kernel memory.
---------------------------------------------------------------------------
diff -Nru a/kernel/module.c b/kernel/module.c
--- a/kernel/module.c Sat Jan 25 12:25:15 2003
+++ b/kernel/module.c Sat Jan 25 12:25:15 2003
@@ -1065,6 +1065,7 @@
/* MODULE_LICENSE() */
DEBUGP("Licence found in section %u\n", i);
licenseindex = i;
+ sechdrs[i].sh_flags &= ~(unsigned long)SHF_ALLOC;
} else if (strcmp(secstrings+sechdrs[i].sh_name,
"__vermagic") == 0 &&
(sechdrs[i].sh_flags & SHF_ALLOC)) {
-----------------------------------------------------------------------------
[email protected], 2003-01-24 21:49:33-06:00, [email protected]
kbuild/modules: Track versions of exported symbols
Store the information on the checksum alongside the rest of the
information on exported symbols. To actually use them, we need
something to check them against first, though ;)
Also, fix some conditional debug code to actually compile.
---------------------------------------------------------------------------
diff -Nru a/include/linux/module.h b/include/linux/module.h
--- a/include/linux/module.h Sat Jan 25 12:25:18 2003
+++ b/include/linux/module.h Sat Jan 25 12:25:18 2003
@@ -119,6 +119,7 @@
unsigned int num_syms;
const struct kernel_symbol *syms;
+ const unsigned long *crcs;
};
/* Given an address, look for it in the exception tables */
diff -Nru a/kernel/module.c b/kernel/module.c
--- a/kernel/module.c Sat Jan 25 12:25:18 2003
+++ b/kernel/module.c Sat Jan 25 12:25:18 2003
@@ -916,7 +916,7 @@
|| strstr(secstrings + s->sh_name, ".init"))
continue;
s->sh_entsize = get_offset(&mod->core_size, s);
- DEBUGP("\t%s\n", name);
+ DEBUGP("\t%s\n", secstrings + s->sh_name);
}
}
@@ -932,7 +932,7 @@
continue;
s->sh_entsize = (get_offset(&mod->init_size, s)
| INIT_OFFSET_MASK);
- DEBUGP("\t%s\n", name);
+ DEBUGP("\t%s\n", secstrings + s->sh_name);
}
}
}
@@ -976,7 +976,8 @@
Elf_Shdr *sechdrs;
char *secstrings, *args;
unsigned int i, symindex, exportindex, strindex, setupindex, exindex,
- modindex, obsparmindex, licenseindex, gplindex, vmagindex;
+ modindex, obsparmindex, licenseindex, gplindex, vmagindex,
+ crcindex, gplcrcindex;
long arglen;
struct module *mod;
long err = 0;
@@ -1012,7 +1013,8 @@
/* May not export symbols, or have setup params, so these may
not exist */
- exportindex = setupindex = obsparmindex = gplindex = licenseindex = 0;
+ exportindex = setupindex = obsparmindex = gplindex = licenseindex
+ = crcindex = gplcrcindex = 0;
/* And these should exist, but gcc whinges if we don't init them */
symindex = strindex = exindex = modindex = vmagindex = 0;
@@ -1045,6 +1047,16 @@
/* Exported symbols. (GPL) */
DEBUGP("GPL symbols found in section %u\n", i);
gplindex = i;
+ } else if (strcmp(secstrings+sechdrs[i].sh_name, "__kcrctab")
+ == 0) {
+ /* Exported symbols CRCs. */
+ DEBUGP("CRC table in section %u\n", i);
+ crcindex = i;
+ } else if (strcmp(secstrings+sechdrs[i].sh_name, "__kcrctab_gpl")
+ == 0) {
+ /* Exported symbols CRCs. (GPL)*/
+ DEBUGP("CRC table in section %u\n", i);
+ gplcrcindex = i;
} else if (strcmp(secstrings+sechdrs[i].sh_name, "__param")
== 0) {
/* Setup parameter info */
@@ -1192,9 +1204,11 @@
mod->symbols.num_syms = (sechdrs[exportindex].sh_size
/ sizeof(*mod->symbols.syms));
mod->symbols.syms = (void *)sechdrs[exportindex].sh_addr;
+ mod->symbols.crcs = (void *)sechdrs[crcindex].sh_addr;
mod->gpl_symbols.num_syms = (sechdrs[gplindex].sh_size
/ sizeof(*mod->symbols.syms));
mod->gpl_symbols.syms = (void *)sechdrs[gplindex].sh_addr;
+ mod->gpl_symbols.crcs = (void *)sechdrs[gplcrcindex].sh_addr;
/* Set up exception table */
if (exindex) {
@@ -1497,6 +1511,10 @@
extern const struct kernel_symbol __stop___ksymtab[];
extern const struct kernel_symbol __start___ksymtab_gpl[];
extern const struct kernel_symbol __stop___ksymtab_gpl[];
+extern const unsigned long __start___kcrctab[];
+extern const unsigned long __stop___kcrctab[];
+extern const unsigned long __start___kcrctab_gpl[];
+extern const unsigned long __stop___kcrctab_gpl[];
static struct kernel_symbol_group kernel_symbols, kernel_gpl_symbols;
@@ -1505,12 +1523,14 @@
/* Add kernel symbols to symbol table */
kernel_symbols.num_syms = (__stop___ksymtab - __start___ksymtab);
kernel_symbols.syms = __start___ksymtab;
+ kernel_symbols.crcs = __start___kcrctab;
kernel_symbols.gplonly = 0;
list_add(&kernel_symbols.list, &symbols);
kernel_gpl_symbols.num_syms = (__stop___ksymtab_gpl
- __start___ksymtab_gpl);
kernel_gpl_symbols.syms = __start___ksymtab_gpl;
+ kernel_gpl_symbols.crcs = __start___kcrctab_gpl;
kernel_gpl_symbols.gplonly = 1;
list_add(&kernel_gpl_symbols.list, &symbols);
-----------------------------------------------------------------------------
[email protected], 2003-01-24 21:51:36-06:00, [email protected]
kbuild: Always link module (.ko) from associated (.o)
For extracting the versions and finding the unresolved symbols, we
need multi-part modules to be linked together already, so this
patch separates the building of the modules as a .o file from generating
the .ko in the next step.
---------------------------------------------------------------------------
diff -Nru a/scripts/Makefile.build b/scripts/Makefile.build
--- a/scripts/Makefile.build Sat Jan 25 12:25:20 2003
+++ b/scripts/Makefile.build Sat Jan 25 12:25:20 2003
@@ -224,15 +224,7 @@
cmd_link_multi-y = $(LD) $(LDFLAGS) $(EXTRA_LDFLAGS) -r -o $@ $(filter $(addprefix $(obj)/,$($(subst $(obj)/,,$(@:.o=-objs))) $($(subst $(obj)/,,$(@:.o=-y)))),$^)
quiet_cmd_link_multi-m = LD [M] $@
-cmd_link_multi-m = $(LD) $(LDFLAGS) $(EXTRA_LDFLAGS) $(LDFLAGS_MODULE) -o $@ $(filter $(addprefix $(obj)/,$($(subst $(obj)/,,$(@:.ko=-objs))) $($(subst $(obj)/,,$(@:.ko=-y)))),$^) init/vermagic.o
-
-quiet_cmd_link_single-m = LD [M] $@
-cmd_link_single-m = $(LD) $(LDFLAGS) $(EXTRA_LDFLAGS) $(LDFLAGS_MODULE) -o $@ $< init/vermagic.o
-
-# Don't rebuilt vermagic.o unless we actually are in the init/ dir
-ifneq ($(obj),init)
-init/vermagic.o: ;
-endif
+cmd_link_multi-m = $(LD) $(LDFLAGS) $(EXTRA_LDFLAGS) $(LDFLAGS_MODULE) -o $@ $(filter $(addprefix $(obj)/,$($(subst $(obj)/,,$(@:.o=-objs))) $($(subst $(obj)/,,$(@:.o=-y)))),$^)
# We would rather have a list of rules like
# foo.o: $(foo-objs)
@@ -241,13 +233,27 @@
$(multi-used-y) : %.o: $(multi-objs-y) FORCE
$(call if_changed,link_multi-y)
-$(multi-used-m:.o=.ko) : %.ko: $(multi-objs-m) init/vermagic.o FORCE
+$(multi-used-m) : %.o: $(multi-objs-m) FORCE
+ $(touch-module)
$(call if_changed,link_multi-m)
-$(single-used-m:.o=.ko) : %.ko: %.o init/vermagic.o FORCE
- $(call if_changed,link_single-m)
+targets += $(multi-used-y) $(multi-used-m)
+
+#
+# Rule to link modules ( .o -> .ko )
+#
+quiet_cmd_link_module = LD [M] $@
+cmd_link_module = $(LD) $(LDFLAGS) $(EXTRA_LDFLAGS) $(LDFLAGS_MODULE) -o $@ $< init/vermagic.o
+
+# Don't rebuilt vermagic.o unless we actually are in the init/ dir
+ifneq ($(obj),init)
+init/vermagic.o: ;
+endif
+
+$(single-used-m:.o=.ko) $(multi-used-m:.o=.ko): %.ko: %.o init/vermagic.o FORCE
+ $(call if_changed,link_module)
-targets += $(multi-used-y) $(multi-used-m:.o=.ko) $(single-used-m:.o=.ko)
+targets += $(single-used-m:.o=.ko) $(multi-used-m:.o=.ko)
# Compile programs on the host
# ===========================================================================
-----------------------------------------------------------------------------
[email protected], 2003-01-24 21:52:47-06:00, [email protected]
kbuild: Don't build final .ko yet when descending with CONFIG_MODVERSIONING
With CONFIG_MODVERSIONING, we need to record the versions of the unresolved
symbols in the final <module>.ko, which we only know after we finished
the descending build. So we only build <module>.o in that case.
Also, keep track of the modules we built, the post-processing step needs
a list of all modules. Keeping track is done by touching
.tmp_versions/path/to/module.ko
---------------------------------------------------------------------------
diff -Nru a/Makefile b/Makefile
--- a/Makefile Sat Jan 25 12:25:23 2003
+++ b/Makefile Sat Jan 25 12:25:23 2003
@@ -260,6 +260,20 @@
CFLAGS += -fomit-frame-pointer
endif
+# When we're building modules with modversions, we need to consider
+# the built-in objects during the descend as well, in order to
+# make sure the checksums are uptodate before we use them.
+
+ifdef CONFIG_MODVERSIONING
+ifeq ($(KBUILD_MODULES),1)
+ifneq ($(KBUILD_BUILTIN),1)
+ KBUILD_BUILTIN := 1
+endif
+endif
+endif
+
+export MODVERDIR := .tmp_versions
+
#
# INSTALL_PATH specifies where to place the updated kernel and system map
# images. Uncomment if you want to place them anywhere other than root.
@@ -388,6 +402,16 @@
.PHONY: prepare
prepare: include/linux/version.h include/asm include/config/MARKER
+ifdef CONFIG_MODVERSIONING
+ifdef KBUILD_MODULES
+ifeq ($(origin SUBDIRS),file)
+ $(Q)rm -rf $(MODVERDIR)
+else
+ @echo '*** Warning: Overriding SUBDIRS on the command line can cause'
+ @echo '*** inconsistencies with module symbol versions'
+endif
+endif
+endif
@echo ' Starting the build. KBUILD_BUILTIN=$(KBUILD_BUILTIN) KBUILD_MODULES=$(KBUILD_MODULES)'
# We need to build init/vermagic.o before descending since all modules
diff -Nru a/scripts/Makefile.build b/scripts/Makefile.build
--- a/scripts/Makefile.build Sat Jan 25 12:25:23 2003
+++ b/scripts/Makefile.build Sat Jan 25 12:25:23 2003
@@ -45,8 +45,15 @@
endif
endif
+ifdef CONFIG_MODVERSIONING
+modules := $(obj-m)
+touch-module = @mkdir -p $(MODVERDIR)/$(@D); touch $(MODVERDIR)/$(@:.o=.ko)
+else
+modules := $(obj-m:.o=.ko)
+endif
+
__build: $(if $(KBUILD_BUILTIN),$(O_TARGET) $(L_TARGET) $(EXTRA_TARGETS)) \
- $(if $(KBUILD_MODULES),$(obj-m:.o=.ko)) \
+ $(if $(KBUILD_MODULES),$(modules)) \
$(subdir-ym) $(build-targets)
@:
@@ -152,6 +159,15 @@
$(call if_changed_dep,cc_o_c)
endif
+# For modversioning, we need to special case single-part modules
+# to mark them in $(MODVERDIR)
+
+ifdef CONFIG_MODVERSIONING
+$(single-used-m): %.o: %.c FORCE
+ $(touch-module)
+ $(call if_changed_rule,vcc_o_c)
+endif
+
quiet_cmd_cc_lst_c = MKLST $@
cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
$(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
@@ -242,6 +258,11 @@
#
# Rule to link modules ( .o -> .ko )
#
+
+# With CONFIG_MODVERSIONING, generation of the final .ko is handled
+# by scripts/Makefile.modver
+ifndef CONFIG_MODVERSIONING
+
quiet_cmd_link_module = LD [M] $@
cmd_link_module = $(LD) $(LDFLAGS) $(EXTRA_LDFLAGS) $(LDFLAGS_MODULE) -o $@ $< init/vermagic.o
@@ -254,6 +275,8 @@
$(call if_changed,link_module)
targets += $(single-used-m:.o=.ko) $(multi-used-m:.o=.ko)
+
+endif
# Compile programs on the host
# ===========================================================================
-----------------------------------------------------------------------------
[email protected], 2003-01-24 21:54:04-06:00, [email protected]
kbuild/modules: Record versions for unresolved symbols
In the case of CONFIG_MODVERSIONING, the build step will only
generate preliminary <module>.o objects, and an additional
postprocessing step is necessary to record the versions of the unresolved
symbols and add them into the final <module>.ko
The version information for unresolved symbols is again recorded into
a special section, "__versions", which contains an array of symbol
name strings and checksum (struct modversion_info). Size is here not
an issue, since this section will not be stored permanently in kernel
memory.
Makefile.modver takes care of the following steps:
o Collect the version information for all exported symbols from vmlinux
and all modules which export symbols.
o For each module, generate a C file which contains the modversion
information for all unresolved symbols in that module.
o For each module, compile that C file to an object file
o Finally, link the <module>.ko using the preliminary <module.o> + the
version information above.
The first two steps are currently done by not very efficient scripting,
so there's room for performance improvement using some helper C code.
---------------------------------------------------------------------------
diff -Nru a/Makefile b/Makefile
--- a/Makefile Sat Jan 25 12:25:26 2003
+++ b/Makefile Sat Jan 25 12:25:26 2003
@@ -262,7 +262,7 @@
# When we're building modules with modversions, we need to consider
# the built-in objects during the descend as well, in order to
-# make sure the checksums are uptodate before we use them.
+# make sure the checksums are uptodate before we record them.
ifdef CONFIG_MODVERSIONING
ifeq ($(KBUILD_MODULES),1)
@@ -508,8 +508,16 @@
# Build modules
-.PHONY: modules
-modules: $(SUBDIRS)
+.PHONY: modules __modversions
+modules: $(SUBDIRS) __modversions
+
+ifdef CONFIG_MODVERSIONING
+
+__modversions: vmlinux $(SUBDIRS)
+ @echo ' Recording module symbol versions.';
+ $(Q)$(MAKE) -rR -f scripts/Makefile.modver
+
+endif
# Install modules
@@ -690,6 +698,7 @@
# Directories removed with 'make mrproper'
MRPROPER_DIRS += \
+ $(MODVERDIR) \
.tmp_export-objs \
include/config \
include/linux/modules
diff -Nru a/include/linux/module.h b/include/linux/module.h
--- a/include/linux/module.h Sat Jan 25 12:25:26 2003
+++ b/include/linux/module.h Sat Jan 25 12:25:26 2003
@@ -33,10 +33,17 @@
#endif
#define MODULE_NAME_LEN (64 - sizeof(unsigned long))
+
struct kernel_symbol
{
unsigned long value;
const char *name;
+};
+
+struct modversion_info
+{
+ unsigned long crc;
+ char name[MODULE_NAME_LEN];
};
/* These are either module local, or the kernel's dummy ones. */
diff -Nru a/scripts/Makefile.modver b/scripts/Makefile.modver
--- a/scripts/Makefile.modver Sat Jan 25 12:25:26 2003
+++ b/scripts/Makefile.modver Sat Jan 25 12:25:26 2003
@@ -2,3 +2,92 @@
# Module versions
# ===========================================================================
+.PHONY: __modversions
+__modversions:
+
+include scripts/Makefile.lib
+
+#
+
+modules := $(patsubst ./%,%,$(shell cd $(MODVERDIR); find . -name \*.ko))
+
+__modversions: $(modules)
+ @:
+
+quiet_cmd_ld_ko_o = LD [M] $@
+ cmd_ld_ko_o = $(LD) $(LDFLAGS) $(LDFLAGS_MODULE) -o $@ \
+ $(filter-out FORCE,$^)
+
+init/vermagic.o: ;
+
+$(modules): %.ko :%.o $(MODVERDIR)/%.o init/vermagic.o FORCE
+ $(call if_changed,ld_ko_o)
+
+targets += $(modules)
+
+
+quiet_cmd_cc_o_c = CC $@
+ cmd_cc_o_c = $(CC) $(CFLAGS) -c -o $@ $<
+
+$(addprefix $(MODVERDIR)/,$(modules:.ko=.o)): %.o: %.c FORCE
+ $(call if_changed,cc_o_c)
+
+targets += $(addprefix $(MODVERDIR)/,$(modules:.ko=.o))
+
+define rule_mkver_o_c
+ echo ' MKVER $@'; \
+ ( echo "#include <linux/module.h>"; \
+ echo ""; \
+ echo "static const struct modversion_info ____versions[]"; \
+ echo "__attribute__((section(\"__versions\"))) = {"; \
+ for sym in `nm -u $<`; do \
+ grep "\"$$sym\"" .tmp_all-versions \
+ || echo "*** Warning: $(<:.o=.ko): \"$$sym\" unresolved!" >&2;\
+ done; \
+ echo "};"; \
+ ) > $@
+endef
+
+$(addprefix $(MODVERDIR)/,$(modules:.ko=.c)): \
+$(MODVERDIR)/%.c: %.o .tmp_all-versions FORCE
+ $(call if_changed_rule,mkver_o_c)
+
+targets += $(addprefix $(MODVERDIR)/,$(modules:.ko=.o.c))
+
+export-objs := $(shell for m in vmlinux $(modules:.ko=.o); do objdump -h $$m | grep -q __ksymtab && echo $$m; done)
+
+cmd_gen-all-versions = mksyms $(export-objs)
+define rule_gen-all-versions
+ echo ' MKSYMS $@'; \
+ for mod in $(export-objs); do \
+ modname=`basename $$mod`; \
+ nm $$mod \
+ | grep ' __crc_' \
+ | sed "s/\([^ ]*\) A __crc_\(.*\)/{ 0x\1, \"\2\" }, \/* $$modname *\//g;s/.* w __crc_\(.*\)/{ 0x0 , \"\1\" }, \/* $$modname *\//g"; \
+ done > $@; \
+ echo 'cmd_$@ := $(cmd_$(1))' > $(@D)/.$(@F).cmd
+endef
+
+.tmp_all-versions: $(export-objs) FORCE
+ $(call if_changed_rule,gen-all-versions)
+
+targets += .tmp_all-versions
+
+# Add FORCE to the prequisites of a target to force it to be always rebuilt.
+# ---------------------------------------------------------------------------
+
+.PHONY: FORCE
+
+FORCE:
+
+# Read all saved command lines and dependencies for the $(targets) we
+# may be building above, using $(if_changed{,_dep}). As an
+# optimization, we don't need to read them if the target does not
+# exist, we will rebuild anyway in that case.
+
+targets := $(wildcard $(sort $(targets)))
+cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
+
+ifneq ($(cmd_files),)
+ include $(cmd_files)
+endif
-----------------------------------------------------------------------------
[email protected], 2003-01-24 21:54:53-06:00, [email protected]
kbuild/modules: Return the index of the symbol from __find_symbol()
We'll need that index to find the version checksum for the symbol in
a bit.
---------------------------------------------------------------------------
diff -Nru a/kernel/module.c b/kernel/module.c
--- a/kernel/module.c Sat Jan 25 12:25:28 2003
+++ b/kernel/module.c Sat Jan 25 12:25:28 2003
@@ -78,6 +78,7 @@
/* Find a symbol, return value and the symbol group */
static unsigned long __find_symbol(const char *name,
struct kernel_symbol_group **group,
+ unsigned int *symidx,
int gplok)
{
struct kernel_symbol_group *ks;
@@ -90,6 +91,8 @@
for (i = 0; i < ks->num_syms; i++) {
if (strcmp(ks->syms[i].name, name) == 0) {
*group = ks;
+ if (symidx)
+ *symidx = i;
return ks->syms[i].value;
}
}
@@ -520,7 +523,7 @@
unsigned long flags;
spin_lock_irqsave(&modlist_lock, flags);
- if (!__find_symbol(symbol, &ksg, 1))
+ if (!__find_symbol(symbol, &ksg, NULL, 1))
BUG();
module_put(ksg->owner);
spin_unlock_irqrestore(&modlist_lock, flags);
@@ -732,9 +735,10 @@
{
struct kernel_symbol_group *ksg;
unsigned long ret;
+ unsigned int symidx;
spin_lock_irq(&modlist_lock);
- ret = __find_symbol(name, &ksg, mod->license_gplok);
+ ret = __find_symbol(name, &ksg, &symidx, mod->license_gplok);
if (ret) {
/* This can fail due to OOM, or module unloading */
if (!use_module(mod, ksg->owner))
@@ -772,7 +776,7 @@
unsigned long value, flags;
spin_lock_irqsave(&modlist_lock, flags);
- value = __find_symbol(symbol, &ksg, 1);
+ value = __find_symbol(symbol, &ksg, NULL, 1);
if (value && !strong_try_module_get(ksg->owner))
value = 0;
spin_unlock_irqrestore(&modlist_lock, flags);
-----------------------------------------------------------------------------
[email protected], 2003-01-24 21:55:37-06:00, [email protected]
kbuild/modules: Check module symbol versions on insmod
Yeah, the final step!
Now that we've got the checksums for the exported symbols and the
checksums of the unresolved symbols for the module we're loading,
let's compare and see.
Again, we allow to load a module which has the version info stripped,
but taint the kernel in that case.
---------------------------------------------------------------------------
diff -Nru a/kernel/module.c b/kernel/module.c
--- a/kernel/module.c Sat Jan 25 12:25:31 2003
+++ b/kernel/module.c Sat Jan 25 12:25:31 2003
@@ -725,11 +725,66 @@
}
#endif /* CONFIG_OBSOLETE_MODPARM */
+#ifdef CONFIG_MODVERSIONING
+static int check_version(Elf_Shdr *sechdrs,
+ unsigned int versindex,
+ const char *symname,
+ struct module *mod,
+ struct kernel_symbol_group *ksg,
+ unsigned int symidx)
+{
+ unsigned long crc;
+ unsigned int i, num_versions;
+ struct modversion_info *versions;
+
+ if (!ksg->crcs) {
+ printk("%s: no CRC for \"%s\" [%s] found: kernel tainted.\n",
+ mod->name, symname,
+ ksg->owner ? ksg->owner->name : "kernel");
+ goto taint;
+ }
+
+ crc = ksg->crcs[symidx];
+
+ versions = (void *) sechdrs[versindex].sh_addr;
+ num_versions = sechdrs[versindex].sh_size
+ / sizeof(struct modversion_info);
+
+ for (i = 0; i < num_versions; i++) {
+ if (strcmp(versions[i].name, symname) != 0)
+ continue;
+
+ if (versions[i].crc == crc)
+ return 1;
+ printk("%s: disagrees about version of symbol %s\n",
+ mod->name, symname);
+ DEBUGP("Found checksum %lX vs module %lX\n",
+ crc, versions[i].crc);
+ return 0;
+ }
+ /* Not in module's version table. OK, but that taints the kernel. */
+ printk("%s: no version for \"%s\" found: kernel tainted.\n",
+ mod->name, symname);
+ taint:
+ tainted |= TAINT_FORCED_MODULE;
+ return 1;
+}
+#else
+static inline int check_version(Elf_Shdr *sechdrs,
+ unsigned int versindex,
+ const char *symname,
+ struct module *mod,
+ struct kernel_symbol_group *ksg,
+ unsigned int symidx)
+{
+ return 1;
+}
+#endif /* CONFIG_MODVERSIONING */
+
/* Resolve a symbol for this module. I.e. if we find one, record usage.
Must be holding module_mutex. */
static unsigned long resolve_symbol(Elf_Shdr *sechdrs,
- unsigned int symindex,
- const char *strtab,
+ unsigned int versindex,
const char *name,
struct module *mod)
{
@@ -740,8 +795,10 @@
spin_lock_irq(&modlist_lock);
ret = __find_symbol(name, &ksg, &symidx, mod->license_gplok);
if (ret) {
- /* This can fail due to OOM, or module unloading */
- if (!use_module(mod, ksg->owner))
+ /* use_module can fail due to OOM, or module unloading */
+ if (!check_version(sechdrs, versindex, name, mod,
+ ksg, symidx) ||
+ !use_module(mod, ksg->owner))
ret = 0;
}
spin_unlock_irq(&modlist_lock);
@@ -828,6 +885,7 @@
static int simplify_symbols(Elf_Shdr *sechdrs,
unsigned int symindex,
unsigned int strindex,
+ unsigned int versindex,
struct module *mod)
{
Elf_Sym *sym = (void *)sechdrs[symindex].sh_addr;
@@ -852,7 +910,7 @@
case SHN_UNDEF:
sym[i].st_value
- = resolve_symbol(sechdrs, symindex, strtab,
+ = resolve_symbol(sechdrs, versindex,
strtab + sym[i].st_name, mod);
/* Ok if resolved. */
@@ -981,7 +1039,7 @@
char *secstrings, *args;
unsigned int i, symindex, exportindex, strindex, setupindex, exindex,
modindex, obsparmindex, licenseindex, gplindex, vmagindex,
- crcindex, gplcrcindex;
+ crcindex, gplcrcindex, versindex;
long arglen;
struct module *mod;
long err = 0;
@@ -1018,7 +1076,7 @@
/* May not export symbols, or have setup params, so these may
not exist */
exportindex = setupindex = obsparmindex = gplindex = licenseindex
- = crcindex = gplcrcindex = 0;
+ = crcindex = gplcrcindex = versindex = 0;
/* And these should exist, but gcc whinges if we don't init them */
symindex = strindex = exindex = modindex = vmagindex = 0;
@@ -1089,6 +1147,13 @@
DEBUGP("Version magic found in section %u\n", i);
vmagindex = i;
sechdrs[i].sh_flags &= ~(unsigned long)SHF_ALLOC;
+ } else if (strcmp(secstrings+sechdrs[i].sh_name,
+ "__versions") == 0 &&
+ (sechdrs[i].sh_flags & SHF_ALLOC)) {
+ /* Module version info (both exported and needed) */
+ DEBUGP("Versions found in section %u\n", i);
+ versindex = i;
+ sechdrs[i].sh_flags &= ~(unsigned long)SHF_ALLOC;
}
#ifdef CONFIG_KALLSYMS
/* symbol and string tables for decoding later. */
@@ -1200,7 +1265,7 @@
set_license(mod, sechdrs, licenseindex);
/* Fix up syms, so that st_value is a pointer to location. */
- err = simplify_symbols(sechdrs, symindex, strindex, mod);
+ err = simplify_symbols(sechdrs, symindex, strindex, versindex, mod);
if (err < 0)
goto cleanup;
On Sat, Jan 25, 2003 at 12:44:39PM -0600, Kai Germaschewski wrote:
Just some small nit-picking..
Sam
diff -Nru a/kernel/module.c b/kernel/module.c
--- a/kernel/module.c Sat Jan 25 12:25:07 2003
+++ b/kernel/module.c Sat Jan 25 12:25:07 2003
+ kernel_gpl_symbols.num_syms = (__stop___ksymtab_gpl
+ - __start___ksymtab_gpl);
The member "num_syms" says something about number of symbols,
but is contains the syms_size. Misleading name.
I can see this was also the case before, but confused me a bit.
+ | $(GENKSYMS) -k $(VERSION).$(PATCHLEVEL).$(SUBLEVEL) \
+ | grep __ver \
+ | sed 's/\#define __ver_\([^ ]*\)[ ]*\([^ ]*\)/__crc_\1 =
+0x\2 ;/g' \
A genksyms replacement should do all the three steps above?
+cmd_link_multi-m = $(LD) $(LDFLAGS) $(EXTRA_LDFLAGS) $(LDFLAGS_MODULE) -o $@
+$(filter $(addprefix $(obj)/,$($(subst $(obj)/,,$(@:.o=-objs))) $($(subst
+$(obj)/,,$(@:.o=-y)))),$^)
The comment
#
# Rule to link composite objects
#
Could tell a bit more:
#
# Rule to link composite objects
# Listed in kbuild makefiles with:
# <composite object>-objs := <list of .o files>
# or
# <composite object>-y := <list of .o files>
#
+cmd_link_module = $(LD) $(LDFLAGS) $(EXTRA_LDFLAGS) $(LDFLAGS_MODULE) -o $@ $<
+init/vermagic.o
How about
ld_modflags = $(LDFLAGS) $(EXTRA_LDFLAGS) $(LDFLAGS_MODULE)
+
+# Don't rebuilt vermagic.o unless we actually are in the init/ dir
+ifneq ($(obj),init)
+init/vermagic.o: ;
+endif
The above magic does not look safe to me when utilising parrallel builds.
At least init/vermagic.o needs to be in the prepare: rule.
+$(multi-used-m) : %.o: $(multi-objs-m) FORCE
I cannot see the need for the "%.o". The "%" is not used - or have
I misunderstood the usage of the above construction?
+ $(touch-module)
Add comment:
+ $(touch-module) # Record update in .tmp_versions/path/to/module.ko
quiet_cmd_link_multi-m = LD [M] $@
-quiet_cmd_link_single-m = LD [M] $@
+quiet_cmd_link_module = LD [M] $@
Inconsistent naming, I would like the old naming back for consistency.
Sam
On Sat, Jan 25, 2003 at 10:56:37PM +0100, Sam Ravnborg wrote:
> +
> +# Don't rebuilt vermagic.o unless we actually are in the init/ dir
> +ifneq ($(obj),init)
> +init/vermagic.o: ;
> +endif
>
> The above magic does not look safe to me when utilising parrallel builds.
> At least init/vermagic.o needs to be in the prepare: rule.
Checked, it is in the prepare: rule, but it looks ugly anyway.
Does it really need to be a prerequisite?
Sam
On Sat, 25 Jan 2003, Sam Ravnborg wrote:
> On Sat, Jan 25, 2003 at 10:56:37PM +0100, Sam Ravnborg wrote:
> > +
> > +# Don't rebuilt vermagic.o unless we actually are in the init/ dir
> > +ifneq ($(obj),init)
> > +init/vermagic.o: ;
> > +endif
> >
> > The above magic does not look safe to me when utilising parrallel builds.
> > At least init/vermagic.o needs to be in the prepare: rule.
>
> Checked, it is in the prepare: rule, but it looks ugly anyway.
> Does it really need to be a prerequisite?
Yes, because we need to rebuild the module when vermagic.o changed,
otherwise we'd end up with stale information in modules.
--Kai
On Sat, 25 Jan 2003, Sam Ravnborg wrote:
> diff -Nru a/kernel/module.c b/kernel/module.c
> --- a/kernel/module.c Sat Jan 25 12:25:07 2003
> +++ b/kernel/module.c Sat Jan 25 12:25:07 2003
>
> + kernel_gpl_symbols.num_syms = (__stop___ksymtab_gpl
> + - __start___ksymtab_gpl);
>
> The member "num_syms" says something about number of symbols,
> but is contains the syms_size. Misleading name.
> I can see this was also the case before, but confused me a bit.
Look at the definition of __{start,stop}__ksymtab and recall C pointer
arithmetics ;) (i.e. if I understood your comment right)
>
> + | $(GENKSYMS) -k $(VERSION).$(PATCHLEVEL).$(SUBLEVEL) \
> + | grep __ver \
> + | sed 's/\#define __ver_\([^ ]*\)[ ]*\([^ ]*\)/__crc_\1 =
> +0x\2 ;/g' \
>
> A genksyms replacement should do all the three steps above?
Yes, I think at some point I should take a look at patching genksyms so
that the post-processing above is not necessary anymore. However, it
doesn't hurt much, performance-wise.
> +cmd_link_multi-m = $(LD) $(LDFLAGS) $(EXTRA_LDFLAGS) $(LDFLAGS_MODULE) -o $@
> +$(filter $(addprefix $(obj)/,$($(subst $(obj)/,,$(@:.o=-objs))) $($(subst
> +$(obj)/,,$(@:.o=-y)))),$^)
>
> The comment
> #
> # Rule to link composite objects
> #
>
> Could tell a bit more:
> #
> # Rule to link composite objects
> # Listed in kbuild makefiles with:
> # <composite object>-objs := <list of .o files>
> # or
> # <composite object>-y := <list of .o files>
> #
Sure, send a patch ;)
> +$(multi-used-m) : %.o: $(multi-objs-m) FORCE
>
> I cannot see the need for the "%.o". The "%" is not used - or have
> I misunderstood the usage of the above construction?
It's not really necessary, but it still gives a hint that we're building
.o files. It should reallyyyy be %.o: $(%-objs), only that make doesn't
like that.
> quiet_cmd_link_multi-m = LD [M] $@
> -quiet_cmd_link_single-m = LD [M] $@
> +quiet_cmd_link_module = LD [M] $@
>
> Inconsistent naming, I would like the old naming back for consistency.
No, cmd_link_module links single- and multi-part modules (.o->.ko) now,
that's why it got the more generic name.
--Kai
In message <[email protected]> you write:
> On Sat, Jan 25, 2003 at 12:44:39PM -0600, Kai Germaschewski wrote:
>
> Just some small nit-picking..
>
> Sam
>
> diff -Nru a/kernel/module.c b/kernel/module.c
> --- a/kernel/module.c Sat Jan 25 12:25:07 2003
> +++ b/kernel/module.c Sat Jan 25 12:25:07 2003
>
> + kernel_gpl_symbols.num_syms = (__stop___ksymtab_gpl
> + - __start___ksymtab_gpl);
>
> The member "num_syms" says something about number of symbols,
> but is contains the syms_size. Misleading name.
I think you've missed the declaration:
extern const struct kernel_symbol __start___ksymtab[];
extern const struct kernel_symbol __stop___ksymtab[];
extern const struct kernel_symbol __start___ksymtab_gpl[];
extern const struct kernel_symbol __stop___ksymtab_gpl[];
Thanks for the feedback!
Rusty.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
In message <[email protected]> yo
u write:
> On Sat, 25 Jan 2003, Sam Ravnborg wrote:
>
> > A genksyms replacement should do all the three steps above?
>
> Yes, I think at some point I should take a look at patching genksyms so
> that the post-processing above is not necessary anymore. However, it
> doesn't hurt much, performance-wise.
Of course, genksyms belongs in the kernel sources, too, since it's
intimately tied to them.
One step at a time...
Rusty.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
In message <[email protected]> you write:
> A kernel built with CONFIG_MODVERSIONING will continue to work fine with
> unpatched module-init-tools, however, forcing the load of a module
> with mismatched symbol versions will need a small patch to
> module-init-tools.
>
> Comments, testing or other feedback are much appreciated ;)
Well done Kai!
But once again you are relying on link order to keep the crcs
section in the same order as the ksymtab section (although the ld
documentation says that's correct, I know RTH doesn't like it). I put
the CRC inside the symbol unconditionally, making for 6k (or 12k on
64-bit) of bloat, which I'm not happy with, either.
I'd recommend changing the name back to CONFIG_MODVERSIONS: I
invented CONFIG_MODVERSIONING because I didn't want to rip the old
stuff out of the makefiles 8) Keep the name the same, and users
migrating from 2.4 won't get asked the question again.
I like the SHF_ALLOC tweak for --force, BTW: it's in the fresh
0.9.9-pre.
Thoughts?
Rusty.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
Name: Tweaks to Module Versions
Author: Rusty Russell
Depends: Module/modversions.patch.gz
Status: Tested on 2.5.59
D: Put crc values into exported symbol structure, rather than relying
D: on link order. Also fixes up help message for
D: CONFIG_MODVERSIONING, and only prints an error the first time the
D: kernel is tainted.
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .24463-2.5.59-modversions2.pre/include/asm-generic/vmlinux.lds.h .24463-2.5.59-modversions2/include/asm-generic/vmlinux.lds.h
--- .24463-2.5.59-modversions2.pre/include/asm-generic/vmlinux.lds.h 2003-01-28 21:29:55.000000000 +1100
+++ .24463-2.5.59-modversions2/include/asm-generic/vmlinux.lds.h 2003-01-28 21:29:57.000000000 +1100
@@ -26,20 +26,6 @@
__stop___ksymtab_gpl = .; \
} \
\
- /* Kernel symbol table: Normal symbols */ \
- __kcrctab : AT(ADDR(__kcrctab) - LOAD_OFFSET) { \
- __start___kcrctab = .; \
- *(__kcrctab) \
- __stop___kcrctab = .; \
- } \
- \
- /* Kernel symbol table: GPL-only symbols */ \
- __kcrctab_gpl : AT(ADDR(__kcrctab_gpl) - LOAD_OFFSET) { \
- __start___kcrctab_gpl = .; \
- *(__kcrctab_gpl) \
- __stop___kcrctab_gpl = .; \
- } \
- \
/* Kernel symbol table: strings */ \
__ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) { \
*(__ksymtab_strings) \
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .24463-2.5.59-modversions2.pre/include/linux/module.h .24463-2.5.59-modversions2/include/linux/module.h
--- .24463-2.5.59-modversions2.pre/include/linux/module.h 2003-01-28 21:29:56.000000000 +1100
+++ .24463-2.5.59-modversions2/include/linux/module.h 2003-01-28 21:29:57.000000000 +1100
@@ -38,6 +38,9 @@ struct kernel_symbol
{
unsigned long value;
const char *name;
+ /* This is here unconditionally, so versioned modules can
+ easily be used in non-versioned kernels and vice-versa. */
+ unsigned long crc;
};
struct modversion_info
@@ -126,7 +129,6 @@ struct kernel_symbol_group
unsigned int num_syms;
const struct kernel_symbol *syms;
- const unsigned long *crcs;
};
/* Given an address, look for it in the exception tables */
@@ -153,29 +155,26 @@ void *__symbol_get_gpl(const char *symbo
/* genksyms doesn't handle GPL-only symbols yet */
#define EXPORT_SYMBOL_GPL EXPORT_SYMBOL
-#else
+#else /* ... !__GENKSYMS__ */
#ifdef CONFIG_MODVERSIONING
-/* Mark the CRC weak since genksyms apparently decides not to
- * generate a checksums for some symbols */
-#define __CRC_SYMBOL(sym, sec) \
- extern void *__crc_##sym __attribute__((weak)); \
- static const unsigned long __kcrctab_##sym \
- __attribute__((section("__kcrctab" sec))) \
- = (unsigned long) &__crc_##sym;
+/* This "address" is really the crc itself, and generated by the linker. */
+#define __CRC_SYMBOL(sym) ((unsigned long)&__crc_##sym)
#else
-#define __CRC_SYMBOL(sym, sec)
+#define __CRC_SYMBOL(sym) NULL
#endif
/* For every exported symbol, place a struct in the __ksymtab section */
-#define __EXPORT_SYMBOL(sym, sec) \
- __CRC_SYMBOL(sym, sec) \
- static const char __kstrtab_##sym[] \
- __attribute__((section("__ksymtab_strings"))) \
- = MODULE_SYMBOL_PREFIX #sym; \
- static const struct kernel_symbol __ksymtab_##sym \
- __attribute__((section("__ksymtab" sec))) \
- = { (unsigned long)&sym, __kstrtab_##sym }
+/* Mark the CRC weak since genksyms apparently decides not to generate
+ a checksums for some symbols */
+#define __EXPORT_SYMBOL(sym, sec) \
+ extern unsigned long __crc_##sym __attribute__((weak)); \
+ static const char __kstrtab_##sym[] \
+ __attribute__((section("__ksymtab_strings"))) \
+ = MODULE_SYMBOL_PREFIX #sym; \
+ static const struct kernel_symbol __ksymtab_##sym \
+ __attribute__((section("__ksymtab" sec))) \
+ = { (unsigned long)&sym, __kstrtab_##sym, __CRC_SYMBOL(sym) }
#define EXPORT_SYMBOL(sym) \
__EXPORT_SYMBOL(sym, "")
@@ -183,7 +182,7 @@ void *__symbol_get_gpl(const char *symbo
#define EXPORT_SYMBOL_GPL(sym) \
__EXPORT_SYMBOL(sym, "_gpl")
-#endif
+#endif /* __GENKSYMS__ */
/* We don't mangle the actual symbol anymore, so no need for
* special casing EXPORT_SYMBOL_NOVERS */
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .24463-2.5.59-modversions2.pre/init/Kconfig .24463-2.5.59-modversions2/init/Kconfig
--- .24463-2.5.59-modversions2.pre/init/Kconfig 2003-01-28 21:29:55.000000000 +1100
+++ .24463-2.5.59-modversions2/init/Kconfig 2003-01-28 21:29:57.000000000 +1100
@@ -147,7 +147,6 @@ config OBSOLETE_MODPARM
config MODVERSIONING
bool "Module versioning support (EXPERIMENTAL)"
depends on MODULES && EXPERIMENTAL
- help
---help---
Usually, you have to use modules compiled with your kernel.
Saying Y here makes it sometimes possible to use modules
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .24463-2.5.59-modversions2.pre/kernel/module.c .24463-2.5.59-modversions2/kernel/module.c
--- .24463-2.5.59-modversions2.pre/kernel/module.c 2003-01-28 21:29:56.000000000 +1100
+++ .24463-2.5.59-modversions2/kernel/module.c 2003-01-28 21:29:57.000000000 +1100
@@ -729,44 +729,40 @@ static int obsolete_params(const char *n
static int check_version(Elf_Shdr *sechdrs,
unsigned int versindex,
const char *symname,
- struct module *mod,
- struct kernel_symbol_group *ksg,
- unsigned int symidx)
+ struct module *mod,
+ const struct kernel_symbol *ksym)
{
- unsigned long crc;
unsigned int i, num_versions;
struct modversion_info *versions;
- if (!ksg->crcs) {
- printk("%s: no CRC for \"%s\" [%s] found: kernel tainted.\n",
- mod->name, symname,
- ksg->owner ? ksg->owner->name : "kernel");
- goto taint;
+ /* Doesn't need a version? OK. */
+ if (!ksym->crc) {
+ DEBUGP("Symbol name %s has no crc\n", symname);
+ return 1;
}
- crc = ksg->crcs[symidx];
-
- versions = (void *) sechdrs[versindex].sh_addr;
- num_versions = sechdrs[versindex].sh_size
- / sizeof(struct modversion_info);
+ versions = (struct modversion_info *)sechdrs[versindex].sh_addr;
+ num_versions = sechdrs[versindex].sh_size/sizeof(versions[0]);
for (i = 0; i < num_versions; i++) {
if (strcmp(versions[i].name, symname) != 0)
continue;
- if (versions[i].crc == crc)
+ if (versions[i].crc == ksym->crc)
return 1;
printk("%s: disagrees about version of symbol %s\n",
mod->name, symname);
DEBUGP("Found checksum %lX vs module %lX\n",
- crc, versions[i].crc);
+ ksym->crc, versions[i].crc);
return 0;
}
+
/* Not in module's version table. OK, but that taints the kernel. */
- printk("%s: no version for \"%s\" found: kernel tainted.\n",
- mod->name, symname);
- taint:
- tainted |= TAINT_FORCED_MODULE;
+ if (!(tainted & TAINT_FORCED_MODULE)) {
+ printk("%s: no version for \"%s\" found: kernel tainted.\n",
+ mod->name, symname);
+ tainted |= TAINT_FORCED_MODULE;
+ }
return 1;
}
#else
@@ -774,8 +770,7 @@ static inline int check_version(Elf_Shdr
unsigned int versindex,
const char *symname,
struct module *mod,
- struct kernel_symbol_group *ksg,
- unsigned int symidx)
+ const struct kernel_symbol *ksym)
{
return 1;
}
@@ -795,10 +790,12 @@ static unsigned long resolve_symbol(Elf_
spin_lock_irq(&modlist_lock);
ret = __find_symbol(name, &ksg, &symidx, mod->license_gplok);
if (ret) {
+ DEBUGP("Found symbol %i in ksg %p (owner %s)\n",
+ symidx, ksg, module_name(ksg->owner));
/* use_module can fail due to OOM, or module unloading */
if (!check_version(sechdrs, versindex, name, mod,
- ksg, symidx) ||
- !use_module(mod, ksg->owner))
+ &ksg->syms[symidx])
+ || !use_module(mod, ksg->owner))
ret = 0;
}
spin_unlock_irq(&modlist_lock);
@@ -1141,20 +1138,23 @@ static struct module *load_module(void *
licenseindex = i;
sechdrs[i].sh_flags &= ~(unsigned long)SHF_ALLOC;
} else if (strcmp(secstrings+sechdrs[i].sh_name,
- "__vermagic") == 0 &&
- (sechdrs[i].sh_flags & SHF_ALLOC)) {
+ "__vermagic") == 0
+ && (sechdrs[i].sh_flags & SHF_ALLOC)) {
/* Version magic. */
DEBUGP("Version magic found in section %u\n", i);
vmagindex = i;
sechdrs[i].sh_flags &= ~(unsigned long)SHF_ALLOC;
- } else if (strcmp(secstrings+sechdrs[i].sh_name,
- "__versions") == 0 &&
- (sechdrs[i].sh_flags & SHF_ALLOC)) {
- /* Module version info (both exported and needed) */
+ }
+
+#ifdef CONFIG_MODVERSIONING
+ if (strcmp(secstrings+sechdrs[i].sh_name, "__versions") == 0
+ && (sechdrs[i].sh_flags & SHF_ALLOC)) {
+ /* Module version info (for needed symbols) */
DEBUGP("Versions found in section %u\n", i);
versindex = i;
sechdrs[i].sh_flags &= ~(unsigned long)SHF_ALLOC;
}
+#endif /* CONFIG_MODVERSIONING */
#ifdef CONFIG_KALLSYMS
/* symbol and string tables for decoding later. */
if (sechdrs[i].sh_type == SHT_SYMTAB || i == strindex)
@@ -1174,12 +1174,15 @@ static struct module *load_module(void *
}
mod = (void *)sechdrs[modindex].sh_addr;
- /* This is allowed: modprobe --force will invalidate it. */
+ /* This is allowed: modprobe --force will invalidate it.
+ Otherwise, if versindex is set, module symbole versions are
+ used instead. */
if (!vmagindex) {
tainted |= TAINT_FORCED_MODULE;
printk(KERN_WARNING "%s: no version magic, tainting kernel.\n",
mod->name);
- } else if (strcmp((char *)sechdrs[vmagindex].sh_addr, vermagic) != 0) {
+ } else if (strcmp((char *)sechdrs[vmagindex].sh_addr, vermagic) != 0
+ && !versindex) {
printk(KERN_ERR "%s: version magic '%s' should be '%s'\n",
mod->name, (char*)sechdrs[vmagindex].sh_addr, vermagic);
err = -ENOEXEC;
@@ -1273,11 +1276,9 @@ static struct module *load_module(void *
mod->symbols.num_syms = (sechdrs[exportindex].sh_size
/ sizeof(*mod->symbols.syms));
mod->symbols.syms = (void *)sechdrs[exportindex].sh_addr;
- mod->symbols.crcs = (void *)sechdrs[crcindex].sh_addr;
mod->gpl_symbols.num_syms = (sechdrs[gplindex].sh_size
/ sizeof(*mod->symbols.syms));
mod->gpl_symbols.syms = (void *)sechdrs[gplindex].sh_addr;
- mod->gpl_symbols.crcs = (void *)sechdrs[gplcrcindex].sh_addr;
/* Set up exception table */
if (exindex) {
@@ -1580,10 +1581,6 @@ extern const struct kernel_symbol __star
extern const struct kernel_symbol __stop___ksymtab[];
extern const struct kernel_symbol __start___ksymtab_gpl[];
extern const struct kernel_symbol __stop___ksymtab_gpl[];
-extern const unsigned long __start___kcrctab[];
-extern const unsigned long __stop___kcrctab[];
-extern const unsigned long __start___kcrctab_gpl[];
-extern const unsigned long __stop___kcrctab_gpl[];
static struct kernel_symbol_group kernel_symbols, kernel_gpl_symbols;
@@ -1592,14 +1589,12 @@ static int __init symbols_init(void)
/* Add kernel symbols to symbol table */
kernel_symbols.num_syms = (__stop___ksymtab - __start___ksymtab);
kernel_symbols.syms = __start___ksymtab;
- kernel_symbols.crcs = __start___kcrctab;
kernel_symbols.gplonly = 0;
list_add(&kernel_symbols.list, &symbols);
kernel_gpl_symbols.num_syms = (__stop___ksymtab_gpl
- __start___ksymtab_gpl);
kernel_gpl_symbols.syms = __start___ksymtab_gpl;
- kernel_gpl_symbols.crcs = __start___kcrctab_gpl;
kernel_gpl_symbols.gplonly = 1;
list_add(&kernel_gpl_symbols.list, &symbols);
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .24463-2.5.59-modversions2.pre/scripts/Makefile.build .24463-2.5.59-modversions2/scripts/Makefile.build
--- .24463-2.5.59-modversions2.pre/scripts/Makefile.build 2003-01-28 21:29:56.000000000 +1100
+++ .24463-2.5.59-modversions2/scripts/Makefile.build 2003-01-28 21:29:57.000000000 +1100
@@ -73,7 +73,7 @@ ifdef CONFIG_MODVERSIONING
# are done.
# o otherwise, we calculate symbol versions using the good old
# genksyms on the preprocessed source and postprocess them in a way
-# that they are usable as a linker script
+# that they are usable as a linker script (replacing 0 crcs with 1).
# o generate <file>.o from .tmp_<file>.o using the linker to
# replace the unresolved symbols __crc_exported_symbol with
# the actual value of the checksum generated by genksyms
@@ -92,6 +92,7 @@ define rule_vcc_o_c
| $(GENKSYMS) -k $(VERSION).$(PATCHLEVEL).$(SUBLEVEL) \
| grep __ver \
| sed 's/\#define __ver_\([^ ]*\)[ ]*\([^ ]*\)/__crc_\1 = 0x\2 ;/g' \
+ | sed 's/\(0x[0]*\)0 ;/\11 ;/' \
> $(@D)/.tmp_$(@F:.o=.ver); \
\
$(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \
On Tue, Jan 28, 2003 at 09:38:31PM +1100, Rusty Russell wrote:
> But once again you are relying on link order to keep the crcs
> section in the same order as the ksymtab section (although the ld
> documentation says that's correct, I know RTH doesn't like it).
What gave you that idea? Link order is a fine thing to rely on.
r~
On Tue, 28 Jan 2003, Richard Henderson wrote:
> On Tue, Jan 28, 2003 at 09:38:31PM +1100, Rusty Russell wrote:
> > But once again you are relying on link order to keep the crcs
> > section in the same order as the ksymtab section (although the ld
> > documentation says that's correct, I know RTH doesn't like it).
>
> What gave you that idea? Link order is a fine thing to rely on.
Cool, so I don't even need to start arguing ;) I was about to suggest
adding a script like per_cpu_check to detect if the linker went crazy on
us and complain, but now I hope rusty is convinced already.
--Kai
On Tue, 28 Jan 2003, Rusty Russell wrote:
> In message <[email protected]> yo
> u write:
> > On Sat, 25 Jan 2003, Sam Ravnborg wrote:
> >
> > > A genksyms replacement should do all the three steps above?
> >
> > Yes, I think at some point I should take a look at patching genksyms so
> > that the post-processing above is not necessary anymore. However, it
> > doesn't hurt much, performance-wise.
>
> Of course, genksyms belongs in the kernel sources, too, since it's
> intimately tied to them.
Yeah, I guess I'll move it there some time. It'd also be possible to make
genksyms just a filter which takes the preprocessed input as a filter,
generates the module symbol checksums and outputs the preprocessed code
with the right versions added.
OTOH, that'd mean that my trick of using the linker to add the checksums
would become obsolete again, though it's sooo cute ;)
--Kai
On Tue, Jan 28, 2003 at 06:06:17PM +1100, Rusty Russell wrote:
> >
> > The member "num_syms" says something about number of symbols,
> > but is contains the syms_size. Misleading name.
>
> I think you've missed the declaration:
>
> extern const struct kernel_symbol __start___ksymtab[];
Yep, for a second I forgot about pointer aritmetics and starting
considering (void *).
Kai already pointed out this to me :-(
Sam
In message <[email protected]> you write:
> On Tue, Jan 28, 2003 at 09:38:31PM +1100, Rusty Russell wrote:
> > But once again you are relying on link order to keep the crcs
> > section in the same order as the ksymtab section (although the ld
> > documentation says that's correct, I know RTH doesn't like it).
>
> What gave you that idea? Link order is a fine thing to rely on.
OK, I stand corrected. Sorry Kai, I guess this means that struct
kernel_symbol can drop the pointer, too. I'll dig out the old patch
and resend it.
I also dropped the "ignore vermagic if modversions set": you were
right that that's a bad idea, too.
So, here is my much reduced patch on top of yours. Please read
carefully since I'm obviously not having a great week 8)
Thanks!
Rusty.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
Name: Tweaks to Module Versions
Author: Rusty Russell
Depends: Module/modversions.patch.gz
Status: Experimental
D: Fix the case where no CRCs are supplied (OK, but taints kernel), and
D: only print one tainted message (otherwise --force gives hundreds of them).
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .1440-linux-2.5.59/init/Kconfig .1440-linux-2.5.59.updated/init/Kconfig
--- .1440-linux-2.5.59/init/Kconfig 2003-01-29 11:13:07.000000000 +1100
+++ .1440-linux-2.5.59.updated/init/Kconfig 2003-01-29 11:14:00.000000000 +1100
@@ -147,7 +147,6 @@ config OBSOLETE_MODPARM
config MODVERSIONING
bool "Module versioning support (EXPERIMENTAL)"
depends on MODULES && EXPERIMENTAL
- help
---help---
Usually, you have to use modules compiled with your kernel.
Saying Y here makes it sometimes possible to use modules
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .1440-linux-2.5.59/kernel/module.c .1440-linux-2.5.59.updated/kernel/module.c
--- .1440-linux-2.5.59/kernel/module.c 2003-01-29 11:13:07.000000000 +1100
+++ .1440-linux-2.5.59.updated/kernel/module.c 2003-01-29 11:13:43.000000000 +1100
@@ -737,12 +737,9 @@ static int check_version(Elf_Shdr *sechd
unsigned int i, num_versions;
struct modversion_info *versions;
- if (!ksg->crcs) {
- printk("%s: no CRC for \"%s\" [%s] found: kernel tainted.\n",
- mod->name, symname,
- ksg->owner ? ksg->owner->name : "kernel");
- goto taint;
- }
+ /* Exporting module didn't supply crcs? OK, we're already tainted. */
+ if (!ksg->crcs)
+ return 1;
crc = ksg->crcs[symidx];
@@ -763,10 +760,11 @@ static int check_version(Elf_Shdr *sechd
return 0;
}
/* Not in module's version table. OK, but that taints the kernel. */
- printk("%s: no version for \"%s\" found: kernel tainted.\n",
- mod->name, symname);
- taint:
- tainted |= TAINT_FORCED_MODULE;
+ if (!(tainted & TAINT_FORCED_MODULE)) {
+ printk("%s: no version for \"%s\" found: kernel tainted.\n",
+ mod->name, symname);
+ tainted |= TAINT_FORCED_MODULE;
+ }
return 1;
}
#else
@@ -1273,11 +1271,23 @@ static struct module *load_module(void *
mod->symbols.num_syms = (sechdrs[exportindex].sh_size
/ sizeof(*mod->symbols.syms));
mod->symbols.syms = (void *)sechdrs[exportindex].sh_addr;
- mod->symbols.crcs = (void *)sechdrs[crcindex].sh_addr;
+ if (crcindex)
+ mod->symbols.crcs = (void *)sechdrs[crcindex].sh_addr;
+
mod->gpl_symbols.num_syms = (sechdrs[gplindex].sh_size
/ sizeof(*mod->symbols.syms));
mod->gpl_symbols.syms = (void *)sechdrs[gplindex].sh_addr;
- mod->gpl_symbols.crcs = (void *)sechdrs[gplcrcindex].sh_addr;
+ if (gplcrcindex)
+ mod->gpl_symbols.crcs = (void *)sechdrs[gplcrcindex].sh_addr;
+
+#ifdef CONFIG_MODVERSIONING
+ if ((mod->symbols.num_syms && !crcindex)
+ || (mod->gpl_symbols.num_syms && !gplcrcindex))
+ printk(KERN_WARNING "%s: No versions for exported symbols."
+ " Tainting kernel.\n", mod->name);
+ tainted |= TAINT_FORCED_MODULE;
+ }
+#endif /* CONFIG_MODVERSIONING */
/* Set up exception table */
if (exindex) {