Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | Subject | Re: [PATCH] x86/build: fix compiler support check for CONFIG_RETPOLINE | From | Zhenzhong Duan <> | Date | Wed, 5 Dec 2018 11:22:16 +0800 |
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Hi Masahiro,
Thanks for fixing. There is a question still confusing me. There are many CONFIG_* used in arch/x86/Makefile. Will they also be impacted or not?
# grep CONFIG_ arch/x86/Makefile ifeq ($(CONFIG_X86_32),y) cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8) cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona) ...... drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/ drivers-$(CONFIG_PCI) += arch/x86/pci/ drivers-$(CONFIG_OPROFILE) += arch/x86/oprofile/ drivers-$(CONFIG_PM) += arch/x86/power/ drivers-$(CONFIG_FB) += arch/x86/video/ ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
Thanks Zhenzhong On 2018/12/5 11:00, Masahiro Yamada wrote: > It is wrong to add CONFIG option diagnostic to the Makefile parse > stage. > > Once you are hit by the error about non-retpoline compiler, the > compilation still breaks even after disabling CONFIG_RETPOLINE. > > The easiest fix is to move this check to the "archprepare" like commit > 829fe4aa9ac1 ("x86: Allow generating user-space headers without a > compiler") did. > > Link: https://lkml.org/lkml/2018/12/4/206 > Reported-by: Meelis Roos <mroos@linux.ee> > Fixes: 4cd24de3a098 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support") > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> > --- > > arch/x86/Makefile | 14 ++++++++------ > 1 file changed, 8 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/Makefile b/arch/x86/Makefile > index f5d7f41..ae0148b 100644 > --- a/arch/x86/Makefile > +++ b/arch/x86/Makefile > @@ -219,12 +219,7 @@ KBUILD_CFLAGS += -Wno-sign-compare > KBUILD_CFLAGS += -fno-asynchronous-unwind-tables > > # Avoid indirect branches in kernel to deal with Spectre > -ifdef CONFIG_RETPOLINE > -ifeq ($(RETPOLINE_CFLAGS),) > - $(error You are building kernel with non-retpoline compiler, please update your compiler.) > -endif > - KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) > -endif > +KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) > > archscripts: scripts_basic > $(Q)$(MAKE) $(build)=arch/x86/tools relocs > @@ -307,6 +302,13 @@ ifndef CC_HAVE_ASM_GOTO > @echo Compiler lacks asm-goto support. > @exit 1 > endif > +ifdef CONFIG_RETPOLINE > +ifeq ($(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
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