From 25896d073d8a0403b07e6dec56f58e6c33678207 Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <yamada.masahiro@socionext.com>
Date: Wed, 5 Dec 2018 15:27:19 +0900
Subject: [PATCH] x86/build: Fix compiler support check for CONFIG_RETPOLINE
Git-commit: 25896d073d8a0403b07e6dec56f58e6c33678207
Patch-mainline: v4.20-rc6
References: bsc#1121017
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 <mroos@linux.ee>
Tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Zhenzhong Duan <zhenzhong.duan@oracle.com>
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 <mingo@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
arch/x86/Makefile | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -230,9 +230,6 @@ KBUILD_AFLAGS += $(mflags-y)
# Avoid indirect branches in kernel to deal with Spectre
ifdef CONFIG_RETPOLINE
RETPOLINE_CFLAGS += $(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register)
-ifeq ($(RETPOLINE_CFLAGS),)
- $(error You are building kernel with non-retpoline compiler, please update your compiler.)
- endif
KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) -DRETPOLINE
endif
@@ -308,9 +305,18 @@ install:
$(Q)$(MAKE) $(build)=$(boot) $@
PHONY += vdso_install
+
vdso_install:
$(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@
+ifdef CONFIG_RETPOLINE
+ifeq ($(RETPOLINE_CFLAGS),)
+ @echo "You are building kernel with non-retpoline compiler." >&2
+ @echo "Please update your compiler." >&2
+ @false
+endif
+endif
+
archclean:
$(Q)rm -rf $(objtree)/arch/i386
$(Q)rm -rf $(objtree)/arch/x86_64