Re: [tip:x86/pti] objtool, retpolines: Integrate objtool with retpoline support more closely

From: Peter Zijlstra
Date: Wed Feb 21 2018 - 09:43:15 EST


On Wed, Feb 21, 2018 at 10:59:14AM +0000, David Woodhouse wrote:
> On Wed, 2018-02-21 at 02:34 -0800, tip-bot for Peter Zijlstra wrote:
> >
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -489,6 +489,11 @@ KBUILD_CFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC)
> >  KBUILD_AFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC)
> >  endif
> >  
> > +ifneq ($(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register),)
> > +  CC_HAS_RETPOLINE := 1
> > +endif
> > +export CC_HAS_RETPOLINE
> > +
>
> That isn't the same as the check in arch/x86/Makefile.

That's because this crossed with the llvm cruft, right? I'll have a
look.