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Subject[PATCH] 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.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

Documentation/dontdiff | 1 -
kernel/.gitignore | 2 --
kernel/Makefile | 11 +----------
kernel/configs.c | 41 +++++++++++++++++++----------------------
4 files changed, 20 insertions(+), 35 deletions(-)

diff --git a/Documentation/dontdiff b/Documentation/dontdiff
index 2228fcc..ef25a06 100644
--- a/Documentation/dontdiff
+++ b/Documentation/dontdiff
@@ -106,7 +106,6 @@ compile.h*
conf
config
config-*
-config_data.h*
config.mak
config.mak.autogen
conmakehash
diff --git a/kernel/.gitignore b/kernel/.gitignore
index b3097bd..6e69910 100644
--- a/kernel/.gitignore
+++ b/kernel/.gitignore
@@ -1,7 +1,5 @@
#
# Generated files
#
-config_data.h
-config_data.gz
timeconst.h
hz.bc
diff --git a/kernel/Makefile b/kernel/Makefile
index 6aa7543..6c57e78 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -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)
diff --git a/kernel/configs.c b/kernel/configs.c
index 2df132b..684c5d8 100644
--- a/kernel/configs.c
+++ b/kernel/configs.c
@@ -30,37 +30,34 @@
#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 (
+" .section .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"
+);

#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 +76,7 @@ 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;
}
--
2.7.4
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