From: Nathan Chancellor natechancellor@gmail.com
Commit a9d57ef15cbe ("x86/retpolines: Disable switch jump tables when retpolines are enabled") added -fno-jump-tables to workaround a GCC issue while deliberately avoiding adding this flag when CONFIG_CC_IS_CLANG is set, which is defined by the kconfig system when CC=clang is provided.
However, this symbol was added in 4.18 in commit 469cb7376c06 ("kconfig: add CC_IS_CLANG and CLANG_VERSION") so it is always undefined in 4.14, meaning -fno-jump-tables gets added when using Clang.
Fix this up by using the equivalent $(cc-name) comparison, which matches what upstream did until commit 076f421da5d4 ("kbuild: replace cc-name test with CONFIG_CC_IS_CLANG").
Fixes: e28951100515 ("x86/retpolines: Disable switch jump tables when retpolines are enabled") Signed-off-by: Nathan Chancellor natechancellor@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -249,7 +249,7 @@ ifdef CONFIG_RETPOLINE # retpoline builds, however, gcc does not for x86. This has # only been fixed starting from gcc stable version 8.4.0 and # onwards, but not for older ones. See gcc bug #86952. - ifndef CONFIG_CC_IS_CLANG + ifneq ($(cc-name), clang) KBUILD_CFLAGS += $(call cc-option,-fno-jump-tables) endif endif