Messages in this thread | | | From | Martin-Éric Racine <> | Date | Tue, 30 Aug 2022 14:42:04 +0300 | Subject | Re: [PATCH] x86/speculation: Avoid LFENCE in FILL_RETURN_BUFFER on CPUs that lack it |
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Greetings,
On Fri, Aug 19, 2022 at 3:15 PM Peter Zijlstra <peterz@infradead.org> wrote: > > On Fri, Aug 19, 2022 at 01:38:27PM +0200, Ben Hutchings wrote: > > > So that puts the whole __FILL_RETURN_BUFFER inside an alternative, and > > we can't have nested alternatives. That's unfortunate. > > Well, both alternatives end with the LFENCE instruction, so I could pull > it out and do two consequtive ALTs, but unrolling the loop for i386 is > a better solution in that the sequence, while larger, removes the need > for the LFENCE.
Have we reached a definitive conclusion on to how to fix this?
Martin-Éric
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