Messages in this thread | | | Date | Wed, 9 Aug 2023 15:12:43 +0200 | From | Peter Zijlstra <> | Subject | Re: [RFC][PATCH 05/17] x86/cpu: Cleanup the untrain mess |
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On Wed, Aug 09, 2023 at 08:51:01AM -0400, Josh Poimboeuf wrote: > On Wed, Aug 09, 2023 at 09:12:23AM +0200, Peter Zijlstra wrote: > > Since there can only be one active return_thunk, there only needs be > > one (matching) untrain_ret. It fundamentally doesn't make sense to > > allow multiple untrain_ret at the same time. > > > > Fold all the 3 different untrain methods into a single (temporary) > > helper stub. > > > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> > > --- > > arch/x86/include/asm/nospec-branch.h | 19 +++++-------------- > > arch/x86/lib/retpoline.S | 7 +++++++ > > 2 files changed, 12 insertions(+), 14 deletions(-) > > > > --- a/arch/x86/include/asm/nospec-branch.h > > +++ b/arch/x86/include/asm/nospec-branch.h > > @@ -272,9 +272,9 @@ > > .endm > > > > #ifdef CONFIG_CPU_UNRET_ENTRY > > -#define CALL_ZEN_UNTRAIN_RET "call zen_untrain_ret" > > +#define CALL_UNTRAIN_RET "call entry_untrain_ret" > > #else > > -#define CALL_ZEN_UNTRAIN_RET "" > > +#define CALL_UNTRAIN_RET "" > > #endif > > > > /* > > @@ -293,15 +293,10 @@ > > defined(CONFIG_CALL_DEPTH_TRACKING) || defined(CONFIG_CPU_SRSO) > > VALIDATE_UNRET_END > > ALTERNATIVE_3 "", \ > > - CALL_ZEN_UNTRAIN_RET, X86_FEATURE_UNRET, \ > > + CALL_UNTRAIN_RET, X86_FEATURE_UNRET, \ > > SRSO doesn't have X86_FEATURE_UNRET set.
Argh.. this stuff doesn't exist at the end anymore, but yeah, that's unfortunate.
I'll see if I can find another intermediate step.
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