Commit ce6ed1c4 authored by Masahiro Yamada's avatar Masahiro Yamada
Browse files

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 8b59cd81 ("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: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
parent 1f09af06

Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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.

include/linux/compiler-version.h

0 → 100644
+14 −0
Original line number Diff line number Diff line 
/* 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.

 */

include/linux/kconfig.h

+0 −2
Original line number Diff line number Diff line
@@ -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

init/Kconfig

+4 −4
Original line number Diff line number Diff line
@@ -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)

scripts/gcc-plugins/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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 \