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kbuild: rebuild GCC plugins when the compiler is upgraded

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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 8b59cd81dc ("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 <torvalds@linux-foundation.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
This commit is contained in:
Masahiro Yamada 2021-03-04 20:37:08 +09:00
parent 1f09af0625
commit ce6ed1c4c9
5 changed files with 20 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
Makefile
View File

@ -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.

14
include/linux/compiler-version.h Normal file
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@ -0,0 +1,14 @@
/* SPDX-License-Identifier: GPL-2.0-only */
#ifdef __LINUX_COMPILER_VERSION_H
#error "Please do not include <linux/compiler-version.h>. 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.
*/

2
include/linux/kconfig.h
View File

@ -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 <generated/autoconf.h>
#ifdef CONFIG_CPU_BIG_ENDIAN

8
init/Kconfig
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@ -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)

1
scripts/gcc-plugins/Makefile
View File

@ -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 \