Hi,
Here are the 8th version of the patchset to enable kernel embedded bootconfig
for non-initrd kernel boot environment. This version fixes a build error when
CONFIG_BLK_DEV_INITRD=n. Previous version is here [1];
[1] https://lore.kernel.org/all/164871505771.178991.7870442736805590948.stgit@devnote2/T/#u
You can embed a bootconfig file into the kernel as a default bootconfig,
which will be used if there is no initrd or no bootconfig is attached to initrd.
This needs 2 options: CONFIG_BOOT_CONFIG_EMBED=y and set the file
path to CONFIG_BOOT_CONFIG_EMBED_FILE. Even if you embed the bootconfig file
to the kernel, it will not be enabled unless you pass "bootconfig" kernel
command line option at boot. Moreover, since this is just a "default"
bootconfig, you can override it with a new bootconfig if you attach another
bootconfig to the initrd (if possible).
The CONFIG_BOOT_CONFIG_EMBED_FILE can take both absolute and relative path.
This is requested by Padmanabha at the below thread[2];
[2] https://lore.kernel.org/all/20220307184011.GA2570@pswork/T/#u
Thank you,
---
Masami Hiramatsu (4):
bootconfig: Make the bootconfig.o as a normal object file
bootconfig: Check the checksum before removing the bootconfig from initrd
bootconfig: Support embedding a bootconfig file in kernel
docs: bootconfig: Add how to embed the bootconfig into kernel
Documentation/admin-guide/bootconfig.rst | 31 ++++++++++++++++++++++--
MAINTAINERS | 1 +
include/linux/bootconfig.h | 10 ++++++++
init/Kconfig | 21 ++++++++++++++++-
init/main.c | 38 +++++++++++++++---------------
lib/.gitignore | 1 +
lib/Makefile | 10 +++++++-
lib/bootconfig-data.S | 10 ++++++++
lib/bootconfig.c | 13 ++++++++++
9 files changed, 111 insertions(+), 24 deletions(-)
create mode 100644 lib/bootconfig-data.S
--
Masami Hiramatsu (Linaro) <[email protected]>
This allows kernel developer to embed a default bootconfig file in
the kernel instead of embedding it in the initrd. This will be good
for who are using the kernel without initrd, or who needs a default
bootconfigs.
This needs to set two kconfigs: CONFIG_BOOT_CONFIG_EMBED=y and set
the file path to CONFIG_BOOT_CONFIG_EMBED_FILE.
Note that you still need 'bootconfig' command line option to load the
embedded bootconfig. Also if you boot using an initrd with a different
bootconfig, the kernel will use the bootconfig in the initrd, instead
of the default bootconfig.
Signed-off-by: Masami Hiramatsu <[email protected]>
---
Changes in v8:
- Fix a build error in CONFIG_BLK_DEV_INITRD=n case.
Changes in v7:
- Change kconfig option name to share the common prefix so that
we can search it easier.
- Make embedded_bootconfig_data readonly.
- Select CONFIG_BLK_DEV_INITRD only if CONFIG_BOOT_CONFIG_EMBED=n
- Remove redundant default settings for new Kconfig options.
Changes in v6:
- Split out the .incbin asm part as bootconfig-data.S according to
Masahiro's comment.
Changes in v5:
- Fix .gitignore to be sorted alphabetically.
- Make default.bconf is cleaned up correctly.
- Allow user to specify relative path to CONFIG_EMBED_BOOT_CONFIG_FILE.
(Thanks Masahiro!)
Changes in v4:
- Avoid updating the default.bconf if the file is not changed.
---
MAINTAINERS | 1 +
include/linux/bootconfig.h | 10 ++++++++++
init/Kconfig | 21 ++++++++++++++++++++-
init/main.c | 22 ++++++++++++----------
lib/.gitignore | 1 +
lib/Makefile | 8 ++++++++
lib/bootconfig-data.S | 10 ++++++++++
lib/bootconfig.c | 13 +++++++++++++
8 files changed, 75 insertions(+), 11 deletions(-)
create mode 100644 lib/bootconfig-data.S
diff --git a/MAINTAINERS b/MAINTAINERS
index c10fbd13080a..88c9d62acd90 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7318,6 +7318,7 @@ S: Maintained
F: Documentation/admin-guide/bootconfig.rst
F: fs/proc/bootconfig.c
F: include/linux/bootconfig.h
+F: lib/bootconfig-data.S
F: lib/bootconfig.c
F: tools/bootconfig/*
F: tools/bootconfig/scripts/*
diff --git a/include/linux/bootconfig.h b/include/linux/bootconfig.h
index a4665c7ab07c..1611f9db878e 100644
--- a/include/linux/bootconfig.h
+++ b/include/linux/bootconfig.h
@@ -289,4 +289,14 @@ int __init xbc_get_info(int *node_size, size_t *data_size);
/* XBC cleanup data structures */
void __init xbc_exit(void);
+/* XBC embedded bootconfig data in kernel */
+#ifdef CONFIG_BOOT_CONFIG_EMBED
+const char * __init xbc_get_embedded_bootconfig(size_t *size);
+#else
+static inline const char *xbc_get_embedded_bootconfig(size_t *size)
+{
+ return NULL;
+}
+#endif
+
#endif
diff --git a/init/Kconfig b/init/Kconfig
index beb5b866c318..e7c75fb7d244 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1347,7 +1347,7 @@ endif
config BOOT_CONFIG
bool "Boot config support"
- select BLK_DEV_INITRD
+ select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED
help
Extra boot config allows system admin to pass a config file as
complemental extension of kernel cmdline when booting.
@@ -1357,6 +1357,25 @@ config BOOT_CONFIG
If unsure, say Y.
+config BOOT_CONFIG_EMBED
+ bool "Embed bootconfig file in the kernel"
+ depends on BOOT_CONFIG
+ help
+ Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the
+ kernel. Usually, the bootconfig file is loaded with the initrd
+ image. But if the system doesn't support initrd, this option will
+ help you by embedding a bootconfig file while building the kernel.
+
+ If unsure, say N.
+
+config BOOT_CONFIG_EMBED_FILE
+ string "Embedded bootconfig file path"
+ depends on BOOT_CONFIG_EMBED
+ help
+ Specify a bootconfig file which will be embedded to the kernel.
+ This bootconfig will be used if there is no initrd or no other
+ bootconfig in the initrd.
+
choice
prompt "Compiler optimization level"
default CC_OPTIMIZE_FOR_PERFORMANCE
diff --git a/init/main.c b/init/main.c
index 4f3ba3b84e34..d00c6f77d0e0 100644
--- a/init/main.c
+++ b/init/main.c
@@ -265,7 +265,7 @@ static int __init loglevel(char *str)
early_param("loglevel", loglevel);
#ifdef CONFIG_BLK_DEV_INITRD
-static void * __init get_boot_config_from_initrd(u32 *_size)
+static void * __init get_boot_config_from_initrd(size_t *_size)
{
u32 size, csum;
char *data;
@@ -312,7 +312,7 @@ static void * __init get_boot_config_from_initrd(u32 *_size)
return data;
}
#else
-static void * __init get_boot_config_from_initrd(u32 *_size)
+static void * __init get_boot_config_from_initrd(size_t *_size)
{
return NULL;
}
@@ -409,14 +409,16 @@ static int __init warn_bootconfig(char *str)
static void __init setup_boot_config(void)
{
static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
- const char *msg;
- int pos;
- u32 size;
- char *data, *err;
- int ret;
+ const char *msg, *data;
+ int pos, ret;
+ size_t size;
+ char *err;
/* Cut out the bootconfig data even if we have no bootconfig option */
data = get_boot_config_from_initrd(&size);
+ /* If there is no bootconfig in initrd, try embedded one. */
+ if (!data)
+ data = xbc_get_embedded_bootconfig(&size);
strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
err = parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL,
@@ -435,8 +437,8 @@ static void __init setup_boot_config(void)
}
if (size >= XBC_DATA_MAX) {
- pr_err("bootconfig size %d greater than max size %d\n",
- size, XBC_DATA_MAX);
+ pr_err("bootconfig size %ld greater than max size %d\n",
+ (long)size, XBC_DATA_MAX);
return;
}
@@ -449,7 +451,7 @@ static void __init setup_boot_config(void)
msg, pos);
} else {
xbc_get_info(&ret, NULL);
- pr_info("Load bootconfig: %d bytes %d nodes\n", size, ret);
+ pr_info("Load bootconfig: %ld bytes %d nodes\n", (long)size, ret);
/* keys starting with "kernel." are passed via cmdline */
extra_command_line = xbc_make_cmdline("kernel");
/* Also, "init." keys are init arguments */
diff --git a/lib/.gitignore b/lib/.gitignore
index e5e217b8307b..54596b634ecb 100644
--- a/lib/.gitignore
+++ b/lib/.gitignore
@@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0-only
/crc32table.h
/crc64table.h
+/default.bconf
/gen_crc32table
/gen_crc64table
/oid_registry_data.c
diff --git a/lib/Makefile b/lib/Makefile
index 4fc48543dc8f..62a103aaabd4 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -277,6 +277,14 @@ $(foreach file, $(libfdt_files), \
lib-$(CONFIG_LIBFDT) += $(libfdt_files)
obj-$(CONFIG_BOOT_CONFIG) += bootconfig.o
+obj-$(CONFIG_BOOT_CONFIG_EMBED) += bootconfig-data.o
+
+$(obj)/bootconfig-data.o: $(obj)/default.bconf
+
+targets += default.bconf
+filechk_defbconf = cat $(or $(real-prereqs), /dev/null)
+$(obj)/default.bconf: $(CONFIG_BOOT_CONFIG_EMBED_FILE) FORCE
+ $(call filechk,defbconf)
obj-$(CONFIG_RBTREE_TEST) += rbtree_test.o
obj-$(CONFIG_INTERVAL_TREE_TEST) += interval_tree_test.o
diff --git a/lib/bootconfig-data.S b/lib/bootconfig-data.S
new file mode 100644
index 000000000000..ef85ba1a82f4
--- /dev/null
+++ b/lib/bootconfig-data.S
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Embed default bootconfig in the kernel.
+ */
+ .section .init.rodata, "aw"
+ .global embedded_bootconfig_data
+embedded_bootconfig_data:
+ .incbin "lib/default.bconf"
+ .global embedded_bootconfig_data_end
+embedded_bootconfig_data_end:
diff --git a/lib/bootconfig.c b/lib/bootconfig.c
index 74f3201ab8e5..c59d26068a64 100644
--- a/lib/bootconfig.c
+++ b/lib/bootconfig.c
@@ -12,6 +12,19 @@
#include <linux/kernel.h>
#include <linux/memblock.h>
#include <linux/string.h>
+
+#ifdef CONFIG_BOOT_CONFIG_EMBED
+/* embedded_bootconfig_data is defined in bootconfig-data.S */
+extern __visible const char embedded_bootconfig_data[];
+extern __visible const char embedded_bootconfig_data_end[];
+
+const char * __init xbc_get_embedded_bootconfig(size_t *size)
+{
+ *size = embedded_bootconfig_data_end - embedded_bootconfig_data;
+ return (*size) ? embedded_bootconfig_data : NULL;
+}
+#endif
+
#else /* !__KERNEL__ */
/*
* NOTE: This is only for tools/bootconfig, because tools/bootconfig will
Since the APIs defined in the bootconfig.o are not individually used,
it is meaningless to build it as library by lib-y. Use obj-y for that.
Reported-by: Masahiro Yamada <[email protected]>
Signed-off-by: Masami Hiramatsu <[email protected]>
---
Changes in v6:
- Newly added.
---
lib/Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/Makefile b/lib/Makefile
index 353bc09ce38d..4fc48543dc8f 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -276,7 +276,7 @@ $(foreach file, $(libfdt_files), \
$(eval CFLAGS_$(file) = -I $(srctree)/scripts/dtc/libfdt))
lib-$(CONFIG_LIBFDT) += $(libfdt_files)
-lib-$(CONFIG_BOOT_CONFIG) += bootconfig.o
+obj-$(CONFIG_BOOT_CONFIG) += bootconfig.o
obj-$(CONFIG_RBTREE_TEST) += rbtree_test.o
obj-$(CONFIG_INTERVAL_TREE_TEST) += interval_tree_test.o
Add a description how to embed the bootconfig file into kernel.
Signed-off-by: Masami Hiramatsu <[email protected]>
---
Changes in v7:
- Rename CONFIG_EMBED_BOOT_CONFIG* to CONFIG_BOOT_CONFIG_EMBED*.
Changes in v5:
- Update CONFIG_EMBED_BOOT_CONFIG_FILE which can accept relative path.
Changes in v3:
- Fix typos.
Changes in v2:
- Corrected the text accoding to Randy's suggestion.
- Do not reccomend to use relative path for CONFIG_EMBED_BOOT_CONFIG_FILE.
---
Documentation/admin-guide/bootconfig.rst | 31 +++++++++++++++++++++++++++---
1 file changed, 28 insertions(+), 3 deletions(-)
diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst
index a1860fc0ca88..d99994345d41 100644
--- a/Documentation/admin-guide/bootconfig.rst
+++ b/Documentation/admin-guide/bootconfig.rst
@@ -158,9 +158,15 @@ Each key-value pair is shown in each line with following style::
Boot Kernel With a Boot Config
==============================
-Since the boot configuration file is loaded with initrd, it will be added
-to the end of the initrd (initramfs) image file with padding, size,
-checksum and 12-byte magic word as below.
+There are two options to boot the kernel with bootconfig: attaching the
+bootconfig to the initrd image or embedding it in the kernel itself.
+
+Attaching a Boot Config to Initrd
+---------------------------------
+
+Since the boot configuration file is loaded with initrd by default,
+it will be added to the end of the initrd (initramfs) image file with
+padding, size, checksum and 12-byte magic word as below.
[initrd][bootconfig][padding][size(le32)][checksum(le32)][#BOOTCONFIG\n]
@@ -196,6 +202,25 @@ To remove the config from the image, you can use -d option as below::
Then add "bootconfig" on the normal kernel command line to tell the
kernel to look for the bootconfig at the end of the initrd file.
+Embedding a Boot Config into Kernel
+-----------------------------------
+
+If you can not use initrd, you can also embed the bootconfig file in the
+kernel by Kconfig options. In this case, you need to recompile the kernel
+with the following configs::
+
+ CONFIG_BOOT_CONFIG_EMBED=y
+ CONFIG_BOOT_CONFIG_EMBED_FILE="/PATH/TO/BOOTCONFIG/FILE"
+
+``CONFIG_BOOT_CONFIG_EMBED_FILE`` requires an absolute path or a relative
+path to the bootconfig file from source tree or object tree.
+The kernel will embed it as the default bootconfig.
+
+Just as when attaching the bootconfig to the initrd, you need ``bootconfig``
+option on the kernel command line to enable the embedded bootconfig.
+
+Note that even if you set this option, you can override the embedded
+bootconfig by another bootconfig which attached to the initrd.
Kernel parameters via Boot Config
=================================
Check the bootconfig's checksum before removing the bootcinfig data
from initrd to avoid modifying initrd by mistake.
This will also simplifies the get_boot_config_from_initrd() interface.
Signed-off-by: Masami Hiramatsu <[email protected]>
---
init/main.c | 22 ++++++++++------------
1 file changed, 10 insertions(+), 12 deletions(-)
diff --git a/init/main.c b/init/main.c
index 560f45c27ffe..4f3ba3b84e34 100644
--- a/init/main.c
+++ b/init/main.c
@@ -265,7 +265,7 @@ static int __init loglevel(char *str)
early_param("loglevel", loglevel);
#ifdef CONFIG_BLK_DEV_INITRD
-static void * __init get_boot_config_from_initrd(u32 *_size, u32 *_csum)
+static void * __init get_boot_config_from_initrd(u32 *_size)
{
u32 size, csum;
char *data;
@@ -299,17 +299,20 @@ static void * __init get_boot_config_from_initrd(u32 *_size, u32 *_csum)
return NULL;
}
+ if (xbc_calc_checksum(data, size) != csum) {
+ pr_err("bootconfig checksum failed\n");
+ return NULL;
+ }
+
/* Remove bootconfig from initramfs/initrd */
initrd_end = (unsigned long)data;
if (_size)
*_size = size;
- if (_csum)
- *_csum = csum;
return data;
}
#else
-static void * __init get_boot_config_from_initrd(u32 *_size, u32 *_csum)
+static void * __init get_boot_config_from_initrd(u32 *_size)
{
return NULL;
}
@@ -408,12 +411,12 @@ static void __init setup_boot_config(void)
static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
const char *msg;
int pos;
- u32 size, csum;
+ u32 size;
char *data, *err;
int ret;
/* Cut out the bootconfig data even if we have no bootconfig option */
- data = get_boot_config_from_initrd(&size, &csum);
+ data = get_boot_config_from_initrd(&size);
strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
err = parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL,
@@ -437,11 +440,6 @@ static void __init setup_boot_config(void)
return;
}
- if (xbc_calc_checksum(data, size) != csum) {
- pr_err("bootconfig checksum failed\n");
- return;
- }
-
ret = xbc_init(data, size, &msg, &pos);
if (ret < 0) {
if (pos < 0)
@@ -470,7 +468,7 @@ static void __init exit_boot_config(void)
static void __init setup_boot_config(void)
{
/* Remove bootconfig data from initrd */
- get_boot_config_from_initrd(NULL, NULL);
+ get_boot_config_from_initrd(NULL);
}
static int __init warn_bootconfig(char *str)
Hello Masami Hiramatsu,
On Wed, Apr 06, 2022 at 11:31:19AM +0900, Masami Hiramatsu wrote:
> This allows kernel developer to embed a default bootconfig file in
> the kernel instead of embedding it in the initrd. This will be good
> for who are using the kernel without initrd, or who needs a default
> bootconfigs.
> This needs to set two kconfigs: CONFIG_BOOT_CONFIG_EMBED=y and set
> the file path to CONFIG_BOOT_CONFIG_EMBED_FILE.
>
> Note that you still need 'bootconfig' command line option to load the
> embedded bootconfig. Also if you boot using an initrd with a different
> bootconfig, the kernel will use the bootconfig in the initrd, instead
> of the default bootconfig.
>
> Signed-off-by: Masami Hiramatsu <[email protected]>
> ---
> Changes in v8:
> - Fix a build error in CONFIG_BLK_DEV_INITRD=n case.
> Changes in v7:
> - Change kconfig option name to share the common prefix so that
> we can search it easier.
> - Make embedded_bootconfig_data readonly.
> - Select CONFIG_BLK_DEV_INITRD only if CONFIG_BOOT_CONFIG_EMBED=n
> - Remove redundant default settings for new Kconfig options.
> Changes in v6:
> - Split out the .incbin asm part as bootconfig-data.S according to
> Masahiro's comment.
> Changes in v5:
> - Fix .gitignore to be sorted alphabetically.
> - Make default.bconf is cleaned up correctly.
> - Allow user to specify relative path to CONFIG_EMBED_BOOT_CONFIG_FILE.
> (Thanks Masahiro!)
> Changes in v4:
> - Avoid updating the default.bconf if the file is not changed.
> ---
> MAINTAINERS | 1 +
> include/linux/bootconfig.h | 10 ++++++++++
> init/Kconfig | 21 ++++++++++++++++++++-
> init/main.c | 22 ++++++++++++----------
> lib/.gitignore | 1 +
> lib/Makefile | 8 ++++++++
> lib/bootconfig-data.S | 10 ++++++++++
> lib/bootconfig.c | 13 +++++++++++++
> 8 files changed, 75 insertions(+), 11 deletions(-)
> create mode 100644 lib/bootconfig-data.S
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index c10fbd13080a..88c9d62acd90 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -7318,6 +7318,7 @@ S: Maintained
> F: Documentation/admin-guide/bootconfig.rst
> F: fs/proc/bootconfig.c
> F: include/linux/bootconfig.h
> +F: lib/bootconfig-data.S
> F: lib/bootconfig.c
> F: tools/bootconfig/*
> F: tools/bootconfig/scripts/*
> diff --git a/include/linux/bootconfig.h b/include/linux/bootconfig.h
> index a4665c7ab07c..1611f9db878e 100644
> --- a/include/linux/bootconfig.h
> +++ b/include/linux/bootconfig.h
> @@ -289,4 +289,14 @@ int __init xbc_get_info(int *node_size, size_t *data_size);
> /* XBC cleanup data structures */
> void __init xbc_exit(void);
>
> +/* XBC embedded bootconfig data in kernel */
> +#ifdef CONFIG_BOOT_CONFIG_EMBED
> +const char * __init xbc_get_embedded_bootconfig(size_t *size);
> +#else
> +static inline const char *xbc_get_embedded_bootconfig(size_t *size)
> +{
> + return NULL;
> +}
> +#endif
> +
> #endif
> diff --git a/init/Kconfig b/init/Kconfig
> index beb5b866c318..e7c75fb7d244 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -1347,7 +1347,7 @@ endif
>
> config BOOT_CONFIG
> bool "Boot config support"
> - select BLK_DEV_INITRD
> + select BLK_DEV_INITRD if !BOOT_CONFIG_EMBED
> help
> Extra boot config allows system admin to pass a config file as
> complemental extension of kernel cmdline when booting.
> @@ -1357,6 +1357,25 @@ config BOOT_CONFIG
>
> If unsure, say Y.
>
> +config BOOT_CONFIG_EMBED
> + bool "Embed bootconfig file in the kernel"
> + depends on BOOT_CONFIG
> + help
> + Embed a bootconfig file given by BOOT_CONFIG_EMBED_FILE in the
> + kernel. Usually, the bootconfig file is loaded with the initrd
> + image. But if the system doesn't support initrd, this option will
> + help you by embedding a bootconfig file while building the kernel.
> +
> + If unsure, say N.
> +
> +config BOOT_CONFIG_EMBED_FILE
> + string "Embedded bootconfig file path"
> + depends on BOOT_CONFIG_EMBED
> + help
> + Specify a bootconfig file which will be embedded to the kernel.
> + This bootconfig will be used if there is no initrd or no other
> + bootconfig in the initrd.
> +
> choice
> prompt "Compiler optimization level"
> default CC_OPTIMIZE_FOR_PERFORMANCE
> diff --git a/init/main.c b/init/main.c
> index 4f3ba3b84e34..d00c6f77d0e0 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -265,7 +265,7 @@ static int __init loglevel(char *str)
> early_param("loglevel", loglevel);
>
> #ifdef CONFIG_BLK_DEV_INITRD
> -static void * __init get_boot_config_from_initrd(u32 *_size)
> +static void * __init get_boot_config_from_initrd(size_t *_size)
> {
> u32 size, csum;
> char *data;
> @@ -312,7 +312,7 @@ static void * __init get_boot_config_from_initrd(u32 *_size)
> return data;
> }
> #else
> -static void * __init get_boot_config_from_initrd(u32 *_size)
> +static void * __init get_boot_config_from_initrd(size_t *_size)
> {
> return NULL;
> }
> @@ -409,14 +409,16 @@ static int __init warn_bootconfig(char *str)
> static void __init setup_boot_config(void)
> {
> static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
> - const char *msg;
> - int pos;
> - u32 size;
> - char *data, *err;
> - int ret;
> + const char *msg, *data;
> + int pos, ret;
> + size_t size;
> + char *err;
>
> /* Cut out the bootconfig data even if we have no bootconfig option */
> data = get_boot_config_from_initrd(&size);
> + /* If there is no bootconfig in initrd, try embedded one. */
> + if (!data)
> + data = xbc_get_embedded_bootconfig(&size);
>
> strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
> err = parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL,
> @@ -435,8 +437,8 @@ static void __init setup_boot_config(void)
> }
>
> if (size >= XBC_DATA_MAX) {
> - pr_err("bootconfig size %d greater than max size %d\n",
> - size, XBC_DATA_MAX);
> + pr_err("bootconfig size %ld greater than max size %d\n",
> + (long)size, XBC_DATA_MAX);
> return;
> }
>
> @@ -449,7 +451,7 @@ static void __init setup_boot_config(void)
> msg, pos);
> } else {
> xbc_get_info(&ret, NULL);
> - pr_info("Load bootconfig: %d bytes %d nodes\n", size, ret);
> + pr_info("Load bootconfig: %ld bytes %d nodes\n", (long)size, ret);
> /* keys starting with "kernel." are passed via cmdline */
> extra_command_line = xbc_make_cmdline("kernel");
> /* Also, "init." keys are init arguments */
> diff --git a/lib/.gitignore b/lib/.gitignore
> index e5e217b8307b..54596b634ecb 100644
> --- a/lib/.gitignore
> +++ b/lib/.gitignore
> @@ -1,6 +1,7 @@
> # SPDX-License-Identifier: GPL-2.0-only
> /crc32table.h
> /crc64table.h
> +/default.bconf
> /gen_crc32table
> /gen_crc64table
> /oid_registry_data.c
> diff --git a/lib/Makefile b/lib/Makefile
> index 4fc48543dc8f..62a103aaabd4 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -277,6 +277,14 @@ $(foreach file, $(libfdt_files), \
> lib-$(CONFIG_LIBFDT) += $(libfdt_files)
>
> obj-$(CONFIG_BOOT_CONFIG) += bootconfig.o
> +obj-$(CONFIG_BOOT_CONFIG_EMBED) += bootconfig-data.o
> +
> +$(obj)/bootconfig-data.o: $(obj)/default.bconf
> +
> +targets += default.bconf
> +filechk_defbconf = cat $(or $(real-prereqs), /dev/null)
> +$(obj)/default.bconf: $(CONFIG_BOOT_CONFIG_EMBED_FILE) FORCE
> + $(call filechk,defbconf)
>
> obj-$(CONFIG_RBTREE_TEST) += rbtree_test.o
> obj-$(CONFIG_INTERVAL_TREE_TEST) += interval_tree_test.o
> diff --git a/lib/bootconfig-data.S b/lib/bootconfig-data.S
> new file mode 100644
> index 000000000000..ef85ba1a82f4
> --- /dev/null
> +++ b/lib/bootconfig-data.S
> @@ -0,0 +1,10 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Embed default bootconfig in the kernel.
> + */
> + .section .init.rodata, "aw"
> + .global embedded_bootconfig_data
> +embedded_bootconfig_data:
> + .incbin "lib/default.bconf"
> + .global embedded_bootconfig_data_end
> +embedded_bootconfig_data_end:
> diff --git a/lib/bootconfig.c b/lib/bootconfig.c
> index 74f3201ab8e5..c59d26068a64 100644
> --- a/lib/bootconfig.c
> +++ b/lib/bootconfig.c
> @@ -12,6 +12,19 @@
> #include <linux/kernel.h>
> #include <linux/memblock.h>
> #include <linux/string.h>
> +
> +#ifdef CONFIG_BOOT_CONFIG_EMBED
> +/* embedded_bootconfig_data is defined in bootconfig-data.S */
> +extern __visible const char embedded_bootconfig_data[];
> +extern __visible const char embedded_bootconfig_data_end[];
> +
> +const char * __init xbc_get_embedded_bootconfig(size_t *size)
> +{
> + *size = embedded_bootconfig_data_end - embedded_bootconfig_data;
> + return (*size) ? embedded_bootconfig_data : NULL;
> +}
> +#endif
> +
> #else /* !__KERNEL__ */
> /*
> * NOTE: This is only for tools/bootconfig, because tools/bootconfig will
>
Tested using llvm 15.0.0 [p1] with FULL and THIN LTO as suggested here [p2],
with full and incremental builds results are as expected and no issues
observed.
[p1] https://download.01.org/0day-ci/cross-package/clang-latest/clang-latest/clang.tar.xz
[p2] https://lore.kernel.org/lkml/[email protected]/
Thanks and Regards,
Padmanabha.S