Messages in this thread | | | Date | Wed, 13 Oct 2021 15:05:20 -0700 | From | Josh Poimboeuf <> | Subject | Re: [PATCH 4/9] x86/alternative: Implement .retpoline_sites support |
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On Wed, Oct 13, 2021 at 11:43:43PM +0200, Peter Zijlstra wrote: > On Wed, Oct 13, 2021 at 02:11:18PM -0700, Josh Poimboeuf wrote: > > On Wed, Oct 13, 2021 at 02:22:21PM +0200, Peter Zijlstra wrote: > > > +#ifdef CONFIG_X86_64 > > > + > > > +/* > > > + * CALL/JMP *%\reg > > > + */ > > > +static int emit_indirect(int op, int reg, u8 *bytes) > > > > X86_64 is already equivalent to STACK_VALIDATION these days, but might > > as well clarify here where the retpoline_sites dependency comes from by > > changing this to '#ifdef CONFIG_STACK_VALIDATION'. > > Yeah, I was contemplating having x86_64 unconditionally select that. > Maybe we should.
As far as I can tell, it already does that:
select HAVE_STACK_VALIDATION if X86_64 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
> Also, I think I've proposed it before, but what about: > > s/STACK_VALIDATION/OBJTOOL/ > > on all that?
How about keeping STACK_VALIDATION, but then having it depend on OBJTOOL, in case anybody cares to extricate the two at some point. Some objtool features (like this one) don't rely on the full validation.
-- Josh
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