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

diff --git a/Makefile b/Makefile
index 8e35d7804fef486600f106bed6a0af036f9d5783..b9ee63d6660c6c7c84103326093bdec949b02e8e 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -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

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 42243869216d0fdd04a5f52d2347650673ae1c7b..2f40de5d82a2c362b699f5211a0fcb4d25d0fa2d 100644 (file)
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -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),)