Commit b2f825bf authored Nov 19, 2021 by Peter Zijlstra Committed by Borislav Petkov Dec 08, 2021

x86: Move RETPOLINE*_CFLAGS to arch Makefile



Currently, RETPOLINE*_CFLAGS are defined in the top-level Makefile
but only x86 makes use of them. Move them there. If ever another
architecture finds the need, it can be reconsidered.

  [ bp: Massage a bit. ]

Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lkml.kernel.org/r/20211119165630.219152765@infradead.org

parent 34115065

Makefile

+0 −11

Original line number	Diff line number	Diff line
		@@ -688,17 +688,6 @@ ifdef CONFIG_FUNCTION_TRACER
		CC_FLAGS_FTRACE := -pg
		endif

		ifdef CONFIG_CC_IS_GCC
		RETPOLINE_CFLAGS := $(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register)
		RETPOLINE_VDSO_CFLAGS := $(call cc-option,-mindirect-branch=thunk-inline -mindirect-branch-register)
		endif
		ifdef CONFIG_CC_IS_CLANG
		RETPOLINE_CFLAGS := -mretpoline-external-thunk
		RETPOLINE_VDSO_CFLAGS := -mretpoline
		endif
		export RETPOLINE_CFLAGS
		export RETPOLINE_VDSO_CFLAGS

		include $(srctree)/arch/$(SRCARCH)/Makefile

		ifdef need-config

arch/x86/Makefile

+11 −0

Original line number	Diff line number	Diff line
		@@ -12,6 +12,17 @@ else
		KBUILD_DEFCONFIG := $(ARCH)_defconfig
		endif

		ifdef CONFIG_CC_IS_GCC
		RETPOLINE_CFLAGS := $(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register)
		RETPOLINE_VDSO_CFLAGS := $(call cc-option,-mindirect-branch=thunk-inline -mindirect-branch-register)
		endif
		ifdef CONFIG_CC_IS_CLANG
		RETPOLINE_CFLAGS := -mretpoline-external-thunk
		RETPOLINE_VDSO_CFLAGS := -mretpoline
		endif
		export RETPOLINE_CFLAGS
		export RETPOLINE_VDSO_CFLAGS

		# For gcc stack alignment is specified with -mpreferred-stack-boundary,
		# clang has the option -mstack-alignment for that purpose.
		ifneq ($(call cc-option, -mpreferred-stack-boundary=4),)