From 37cd19b0e1e70592d3d547360bf979f69514f3c1 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Wed, 5 Dec 2018 15:27:19 +0900 Subject: [PATCH 1/2] x86/build: Fix compiler support check for CONFIG_RETPOLINE commit 25896d073d8a0403b07e6dec56f58e6c33678207 upstream. 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 this commit did: 829fe4aa9ac1 ("x86: Allow generating user-space headers without a compiler") Reported-by: Meelis Roos Tested-by: Meelis Roos Signed-off-by: Masahiro Yamada Acked-by: Zhenzhong Duan Cc: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Zhenzhong Duan Fixes: 4cd24de3a098 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support") Link: http://lkml.kernel.org/r/1543991239-18476-1-git-send-email-yamada.masahiro@socionext.com Link: https://lkml.org/lkml/2018/12/4/206 Signed-off-by: Ingo Molnar [bwh: Backported to 4.9: adjust context] Signed-off-by: Ben Hutchings --- arch/x86/Makefile | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/arch/x86/Makefile b/arch/x86/Makefile index a69cfa33f986..a77737a979c8 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -221,9 +221,6 @@ ifdef CONFIG_RETPOLINE RETPOLINE_CFLAGS_CLANG := -mretpoline-external-thunk RETPOLINE_CFLAGS += $(call cc-option,$(RETPOLINE_CFLAGS_GCC),$(call cc-option,$(RETPOLINE_CFLAGS_CLANG))) - ifeq ($(RETPOLINE_CFLAGS),) - $(error You are building kernel with non-retpoline compiler, please update your compiler.) - endif KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) endif @@ -240,6 +237,13 @@ archscripts: scripts_basic ifeq ($(CONFIG_KEXEC_FILE),y) $(Q)$(MAKE) $(build)=arch/x86/purgatory arch/x86/purgatory/kexec-purgatory.c endif +ifdef CONFIG_RETPOLINE +ifeq ($(RETPOLINE_CFLAGS),) + @echo "You are building kernel with non-retpoline compiler." >&2 + @echo "Please update your compiler." >&2 + @false +endif +endif ### # Kernel objects