Messages in this thread | | | Subject | Re: [PATCH v2] x86/build: fix compiler support check for CONFIG_RETPOLINE | From | Zhenzhong Duan <> | Date | Wed, 5 Dec 2018 15:10:49 +0800 |
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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 <mroos@linux.ee> > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> > --- > > 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 Spectre > ifdef 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 > +endif > > archclean: > $(Q)rm -rf $(objtree)/arch/i386 Acked-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
-- Regards Zhenzhong
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