x86: Move x86-retpoline CFLAGS into x86 Makefile.

This patch moves the definition of RETPOLINE_CFLAGS*
into the arch specific Makefile to allow other architectures
to define their own retpoline CFLAGS.

Signed-off-by: Christoph Muellner <christoph.muellner@theobroma-systems.com>

2 files changed, 12 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index ded9e8480d74..010e353523e0 100644
--- a/Makefile
+++ b/Makefile
@@ -496,6 +496,13 @@ RETPOLINE_CFLAGS_CLANG := -mretpoline-external-thunk
 RETPOLINE_CFLAGS := $(call cc-option,$(RETPOLINE_CFLAGS_GCC),$(call cc-option,$(RETPOLINE_CFLAGS_CLANG)))
 export RETPOLINE_CFLAGS
 
+# check for 'asm goto'
+ifeq ($(call shell-cached,$(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC) $(KBUILD_CFLAGS)), y)
+  CC_HAVE_ASM_GOTO := 1
+  KBUILD_CFLAGS += -DCC_HAVE_ASM_GOTO
+  KBUILD_AFLAGS += -DCC_HAVE_ASM_GOTO
+endif
+
 ifeq ($(config-targets),1)
 # ===========================================================================
 # *config targets only - make sure prerequisites are updated, and descend
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 1c4d012550ec..33aab24c7b2c 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -239,6 +239,11 @@ KBUILD_CFLAGS += -Wno-sign-compare
 #
 KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
 
+RETPOLINE_CFLAGS_GCC := -mindirect-branch=thunk-extern -mindirect-branch-register
+RETPOLINE_CFLAGS_CLANG := -mretpoline-external-thunk
+RETPOLINE_CFLAGS := $(call cc-option,$(RETPOLINE_CFLAGS_GCC),$(call cc-option,$(RETPOLINE_CFLAGS_CLANG)))
+export RETPOLINE_CFLAGS
+
 # Avoid indirect branches in kernel to deal with Spectre
 ifdef CONFIG_RETPOLINE
 ifneq ($(RETPOLINE_CFLAGS),)