From: Masahiro Yamada masahiroy@kernel.org
mainline inclusion from mainline-v5.8-rc1 commit 8b59cd81dc5e724eaea283fa6006985891c7bff4 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I8J6X4 CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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Commit 21c54b774744 ("kconfig: show compiler version text in the top comment") added the environment variable, CC_VERSION_TEXT in the comment of the top Kconfig file. It can detect the compiler update, and invoke the syncconfig because all environment variables referenced in Kconfig files are recorded in include/config/auto.conf.cmd
This commit makes it a CONFIG option in order to ensure the full rebuild when the compiler is updated.
This works like follows:
include/config/kconfig.h contains "CONFIG_CC_VERSION_TEXT" in the comment block.
The top Makefile specifies "-include $(srctree)/include/linux/kconfig.h" to guarantee it is included from all kernel source files.
fixdep parses every source file and all headers included from it, searching for words prefixed with "CONFIG_". Then, fixdep finds CONFIG_CC_VERSION_TEXT in include/config/kconfig.h and adds include/config/cc/version/text.h into every .*.cmd file.
When the compiler is updated, syncconfig is invoked because init/Kconfig contains the reference to the environment variable CC_VERTION_TEXT. CONFIG_CC_VERSION_TEXT is updated to the new version string, and include/config/cc/version/text.h is touched.
In the next rebuild, Make will rebuild every files since the timestamp of include/config/cc/version/text.h is newer than that of target.
Signed-off-by: Masahiro Yamada masahiroy@kernel.org Signed-off-by: Zhang Changzhong zhangchangzhong@huawei.com --- Kconfig | 2 -- include/linux/kconfig.h | 2 ++ init/Kconfig | 17 +++++++++++++++++ 3 files changed, 19 insertions(+), 2 deletions(-)
diff --git a/Kconfig b/Kconfig index 48a80beab685..e484b19dc555 100644 --- a/Kconfig +++ b/Kconfig @@ -5,8 +5,6 @@ # mainmenu "Linux/$(ARCH) $(KERNELVERSION) Kernel Configuration"
-comment "Compiler: $(CC_VERSION_TEXT)" - source "scripts/Kconfig.include"
source "init/Kconfig" diff --git a/include/linux/kconfig.h b/include/linux/kconfig.h index cc8fa109cfa3..9d12c970f18f 100644 --- a/include/linux/kconfig.h +++ b/include/linux/kconfig.h @@ -2,6 +2,8 @@ #ifndef __LINUX_KCONFIG_H #define __LINUX_KCONFIG_H
+/* CONFIG_CC_VERSION_TEXT (Do not delete this comment. See help in Kconfig) */ + #include <generated/autoconf.h>
#ifdef CONFIG_CPU_BIG_ENDIAN diff --git a/init/Kconfig b/init/Kconfig index ef1768d36a05..bc12d958b742 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -8,6 +8,23 @@ config DEFCONFIG_LIST default ARCH_DEFCONFIG default "arch/$(ARCH)/defconfig"
+config CC_VERSION_TEXT + string + default "$(CC_VERSION_TEXT)" + help + This is used in unclear ways: + + - Re-run Kconfig when the compiler is updated + The 'default' property references the environment variable, + CC_VERSION_TEXT so it is recorded in include/config/auto.conf.cmd. + When the compiler is updated, Kconfig will be invoked. + + - Ensure full rebuild when the compier is updated + include/linux/kconfig.h contains this option in the comment line so + fixdep adds include/config/cc/version/text.h into the auto-generated + dependency. When the compiler is updated, syncconfig will touch it + and then every file will be rebuilt. + config CC_IS_GCC def_bool $(success,$(CC) --version | head -n 1 | grep -q gcc)