On 2018/12/5 14:27, Masahiro Yamada wrote:
It is troublesome to add a diagnostic like this to the Makefile parse stage because the top-level Makefile could be parsed with a stale include/config/auto.conf. Once you are hit by the error about non-retpoline compiler, the compilation still breaks even after disabling CONFIG_RETPOLINE. The easiest fix is to move this check to the "archprepare" like commit 829fe4aa9ac1 ("x86: Allow generating user-space headers without a compiler") did. Link: https://lkml.org/lkml/2018/12/4/206 Fixes: 4cd24de3a098 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support") Reported-by: Meelis Roos <[email protected]> Signed-off-by: Masahiro Yamada <[email protected]> --- Changes in v2: - Revive ifdef CONFIG_RETPOLINE surrounding the KBUILD_CFLAGS addition - Rephase the commit log a bit, hoping the cause of the issue will be clearer arch/x86/Makefile | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/arch/x86/Makefile b/arch/x86/Makefile index f5d7f41..75ef499 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -220,9 +220,6 @@ KBUILD_CFLAGS += -fno-asynchronous-unwind-tables# Avoid indirect branches in kernel to deal with Spectreifdef CONFIG_RETPOLINE -ifeq ($(RETPOLINE_CFLAGS),) - $(error You are building kernel with non-retpoline compiler, please update your compiler.) -endif KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) endif@@ -307,6 +304,13 @@ ifndef CC_HAVE_ASM_GOTO@echo Compiler lacks asm-goto support. @exit 1 endif +ifdef CONFIG_RETPOLINE +ifeq ($(RETPOLINE_CFLAGS),) + @echo "You are building kernel with non-retpoline compiler." >&2 + @echo "Please update your compiler." >&2 + @false +endif +endifarchclean:$(Q)rm -rf $(objtree)/arch/i386
Acked-by: Zhenzhong Duan <[email protected]> -- Regards Zhenzhong
