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

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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: Masahiro 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Masahiro Yamada 2019-03-07 16:29:53 -08:00 committed by Linus Torvalds
parent 3337d5cfe5
commit 13610aa908
4 changed files with 21 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
Documentation/dontdiff
View File

@ -106,7 +106,6 @@ compile.h*
conf
config
config-*
config_data.h*
config.mak
config.mak.autogen
conmakehash

2
kernel/.gitignore vendored
View File

@ -1,7 +1,5 @@
#
# Generated files
#
config_data.h
config_data.gz
timeconst.h
hz.bc

11
kernel/Makefile
View File

@ -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)

42
kernel/configs.c
View File

@ -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;
}