On Mon, Feb 12, 2018 at 12:57:40PM +0000, David Woodhouse wrote: > > > On Mon, 2018-02-12 at 13:48 +0100, Peter Zijlstra wrote: > > --- a/Makefile > > +++ b/Makefile > > @@ -486,6 +486,11 @@ KBUILD_CFLAGS += $(CLANG_TARGET) $(CLANG > > 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 > > Can't you do that with the existing check in arch/x86/Makefile?
I couldn't make it work there, but it could be my makefile foo isn't strong enough. The ordering of arch/*/Makefile vs scripts/Makefile.build is forever confusing me.
