From: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> Subject: 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@xxxxxxxxxxxxx: v2] Link: http://lkml.kernel.org/r/1550108893-21226-1-git-send-email-yamada.masahiro@xxxxxxxxxxxxx Link: http://lkml.kernel.org/r/1549941160-8084-1-git-send-email-yamada.masahiro@xxxxxxxxxxxxx Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Alexander Popov <alex.popov@xxxxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Jonathan Corbet <corbet@xxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> Cc: Richard Guy Briggs <rgb@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- --- a/Documentation/dontdiff~kernel-configs-use-incbin-directive-to-embed-config_datagz +++ a/Documentation/dontdiff @@ -106,7 +106,6 @@ compile.h* conf config config-* -config_data.h* config.mak config.mak.autogen conmakehash --- a/kernel/configs.c~kernel-configs-use-incbin-directive-to-embed-config_datagz +++ a/kernel/configs.c @@ -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; } --- a/kernel/.gitignore~kernel-configs-use-incbin-directive-to-embed-config_datagz +++ a/kernel/.gitignore @@ -1,7 +1,5 @@ # # Generated files # -config_data.h -config_data.gz timeconst.h hz.bc --- a/kernel/Makefile~kernel-configs-use-incbin-directive-to-embed-config_datagz +++ a/kernel/Makefile @@ -116,17 +116,8 @@ obj-$(CONFIG_GCC_PLUGIN_STACKLEAK) += st KASAN_SANITIZE_stackleak.o := n KCOV_INSTRUMENT_stackleak.o := n -$(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) _
