From ce6ed1c4c9876c2880f52f18c41ef2a30d070bc5 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 4 Mar 2021 20:37:08 +0900 Subject: [PATCH] kbuild: rebuild GCC plugins when the compiler is upgraded Linus reported a build error due to the GCC plugin incompatibility when the compiler is upgraded. [1] GCC plugins are tied to a particular GCC version. So, they must be rebuilt when the compiler is upgraded. This seems to be a long-standing flaw since the initial support of GCC plugins. Extend commit 8b59cd81dc5e ("kbuild: ensure full rebuild when the compiler is updated"), so that GCC plugins are covered by the compiler upgrade detection. [1]: https://lore.kernel.org/lkml/CAHk-=wieoN5ttOy7SnsGwZv+Fni3R6m-Ut=oxih6bbZ28G+4dw@mail.gmail.com/ Reported-by: Linus Torvalds Signed-off-by: Masahiro Yamada Reviewed-by: Kees Cook --- Makefile | 1 + include/linux/compiler-version.h | 14 ++++++++++++++ include/linux/kconfig.h | 2 -- init/Kconfig | 8 ++++---- scripts/gcc-plugins/Makefile | 1 + 5 files changed, 20 insertions(+), 6 deletions(-) create mode 100644 include/linux/compiler-version.h diff --git a/Makefile b/Makefile index 3f9f44eac27f..10bb0a62cc7d 100644 --- a/Makefile +++ b/Makefile @@ -479,6 +479,7 @@ USERINCLUDE := \ -I$(objtree)/arch/$(SRCARCH)/include/generated/uapi \ -I$(srctree)/include/uapi \ -I$(objtree)/include/generated/uapi \ + -include $(srctree)/include/linux/compiler-version.h \ -include $(srctree)/include/linux/kconfig.h # Use LINUXINCLUDE when you must reference the include/ directory. diff --git a/include/linux/compiler-version.h b/include/linux/compiler-version.h new file mode 100644 index 000000000000..2b2972c77c62 --- /dev/null +++ b/include/linux/compiler-version.h @@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifdef __LINUX_COMPILER_VERSION_H +#error "Please do not include . This is done by the build system." +#endif +#define __LINUX_COMPILER_VERSION_H + +/* + * This header exists to force full rebuild when the compiler is upgraded. + * + * When fixdep scans this, it will find this string "CONFIG_CC_VERSION_TEXT" + * and add dependency on include/config/cc/version/text.h, which is touched + * by Kconfig when the version string from the compiler changes. + */ diff --git a/include/linux/kconfig.h b/include/linux/kconfig.h index e78e17a76dc9..24a59cb06963 100644 --- a/include/linux/kconfig.h +++ b/include/linux/kconfig.h @@ -2,8 +2,6 @@ #ifndef __LINUX_KCONFIG_H #define __LINUX_KCONFIG_H -/* CONFIG_CC_VERSION_TEXT (Do not delete this comment. See help in Kconfig) */ - #include #ifdef CONFIG_CPU_BIG_ENDIAN diff --git a/init/Kconfig b/init/Kconfig index 22946fe5ded9..30c849094c28 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -20,10 +20,10 @@ config CC_VERSION_TEXT When the compiler is updated, Kconfig will be invoked. - Ensure full rebuild when the compiler 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. + include/linux/compiler-version.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 $(success,test "$(cc-name)" = GCC) diff --git a/scripts/gcc-plugins/Makefile b/scripts/gcc-plugins/Makefile index b5487cce69e8..1952d3bb80c6 100644 --- a/scripts/gcc-plugins/Makefile +++ b/scripts/gcc-plugins/Makefile @@ -22,6 +22,7 @@ always-y += $(GCC_PLUGIN) GCC_PLUGINS_DIR = $(shell $(CC) -print-file-name=plugin) plugin_cxxflags = -Wp,-MMD,$(depfile) $(KBUILD_HOSTCXXFLAGS) -fPIC \ + -include $(srctree)/include/linux/compiler-version.h \ -I $(GCC_PLUGINS_DIR)/include -I $(obj) -std=gnu++11 \ -fno-rtti -fno-exceptions -fasynchronous-unwind-tables \ -ggdb -Wno-narrowing -Wno-unused-variable \