Commit 13610aa9 authored by Masahiro Yamada's avatar Masahiro Yamada Committed by Linus Torvalds
Browse files

kernel/configs: use .incbin directive to embed config_data.gz 

This slightly optimizes the kernel/configs.c build.

bin2c is not very efficient because it converts a data file into a huge
array to embed it into a *.c file.

Instead, we can use the .incbin directive.

Also, this simplifies the code; Makefile is cleaner, and the way to get
the offset/size of the config_data.gz is more straightforward.

I used the "asm" statement in *.c instead of splitting it into *.S
because MODULE_* tags are not supported in *.S files.

I also cleaned up kernel/.gitignore; "config_data.gz" is unneeded
because the top-level .gitignore takes care of the "*.gz" pattern.

[yamada.masahiro@socionext.com: v2]
  Link: http://lkml.kernel.org/r/1550108893-21226-1-git-send-email-yamada.masahiro@socionext.com
Link: http://lkml.kernel.org/r/1549941160-8084-1-git-send-email-yamada.masahiro@socionext.com


Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Alexander Popov <alex.popov@linux.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3337d5cf

Documentation/dontdiff

+0 −1
Original line number Diff line number Diff line
@@ -106,7 +106,6 @@ compile.h* 
conf

config

config-*

config_data.h*

config.mak

config.mak.autogen

conmakehash

kernel/.gitignore

+0 −2
Original line number Diff line number Diff line 
#

# Generated files

#

config_data.h

config_data.gz

timeconst.h

hz.bc

kernel/Makefile

+1 −10
Original line number Diff line number Diff line
@@ -116,17 +116,8 @@ obj-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak.o 
KASAN_SANITIZE_stackleak.o := n

KCOV_INSTRUMENT_stackleak.o := n



$(obj)/configs.o: $(obj)/config_data.h

$(obj)/configs.o: $(obj)/config_data.gz



targets += config_data.gz

$(obj)/config_data.gz: $(KCONFIG_CONFIG) FORCE

	$(call if_changed,gzip)
 


filechk_ikconfiggz = \

	echo "static const char kernel_config_data[] __used = MAGIC_START"; \

	cat $< | scripts/bin2c; \

	echo "MAGIC_END;"



targets += config_data.h

$(obj)/config_data.h: $(obj)/config_data.gz FORCE

	$(call filechk,ikconfiggz)

kernel/configs.c

+20 −22
Original line number Diff line number Diff line
@@ -30,37 +30,35 @@ 
#include <linux/init.h>

#include <linux/uaccess.h>



/**************************************************/

/* the actual current config file                 */



/*

 * Define kernel_config_data and kernel_config_data_size, which contains the

 * wrapped and compressed configuration file.  The file is first compressed

 * with gzip and then bounded by two eight byte magic numbers to allow

 * extraction from a binary kernel image:

 *

 *   IKCFG_ST

 *   <image>

 *   IKCFG_ED

 * "IKCFG_ST" and "IKCFG_ED" are used to extract the config data from

 * a binary kernel image or a module. See scripts/extract-ikconfig.

 */

#define MAGIC_START	"IKCFG_ST"

#define MAGIC_END	"IKCFG_ED"

#include "config_data.h"





#define MAGIC_SIZE (sizeof(MAGIC_START) - 1)

#define kernel_config_data_size \

	(sizeof(kernel_config_data) - 1 - MAGIC_SIZE * 2)

asm (

"	.pushsection .rodata, \"a\"		\n"

"	.ascii \"IKCFG_ST\"			\n"

"	.global kernel_config_data		\n"

"kernel_config_data:				\n"

"	.incbin \"kernel/config_data.gz\"	\n"

"	.global kernel_config_data_end		\n"

"kernel_config_data_end:			\n"

"	.ascii \"IKCFG_ED\"			\n"

"	.popsection				\n"

);



#ifdef CONFIG_IKCONFIG_PROC



extern char kernel_config_data;

extern char kernel_config_data_end;



static ssize_t

ikconfig_read_current(struct file *file, char __user *buf,

		      size_t len, loff_t * offset)

{

	return simple_read_from_buffer(buf, len, offset,

				       kernel_config_data + MAGIC_SIZE,

				       kernel_config_data_size);

				       &kernel_config_data,

				       &kernel_config_data_end -

				       &kernel_config_data);

}



static const struct file_operations ikconfig_file_ops = {
@@ -79,7 +77,7 @@ static int __init ikconfig_init(void) 
	if (!entry)

		return -ENOMEM;



	proc_set_size(entry, kernel_config_data_size);

	proc_set_size(entry, &kernel_config_data_end - &kernel_config_data);



	return 0;

}

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