Messages in this thread | | | Date | Fri, 19 Aug 2022 14:15:46 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH] x86/speculation: Avoid LFENCE in FILL_RETURN_BUFFER on CPUs that lack it |
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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.
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