Commit a2a9d67a authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Steven Rostedt (Google)
Browse files

bootconfig: Support embedding a bootconfig file in kernel 

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.

Link: https://lkml.kernel.org/r/164921227943.1090670.14035119557571329218.stgit@devnote2



Cc: Padmanabha Srinivasaiah <treasure4paddy@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>
Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 765b8552

MAINTAINERS

+1 −0
Original line number Diff line number Diff line
@@ -7457,6 +7457,7 @@ 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/*

include/linux/bootconfig.h

+10 −0
Original line number Diff line number Diff line
@@ -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

init/Kconfig

+20 −1
Original line number Diff line number Diff line
@@ -1351,7 +1351,7 @@ 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.
@@ -1361,6 +1361,25 @@ 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

init/main.c

+12 −10
Original line number Diff line number Diff line
@@ -266,7 +266,7 @@ 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;
@@ -313,7 +313,7 @@ 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;

}
@@ -410,14 +410,16 @@ 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,
@@ -436,8 +438,8 @@ 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;

	}
@@ -450,7 +452,7 @@ 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 */

lib/.gitignore

+1 −0
Original line number Diff line number Diff line 
# SPDX-License-Identifier: GPL-2.0-only

/crc32table.h

/crc64table.h

/default.bconf

/gen_crc32table

/gen_crc64table

/oid_registry_data.c