Re: [PATCH v11 9/9] arm64: armv8_deprecated: apply FEAT_LSUI for swpX emulation.

[Yeoreum Yun]

Hi Arnd,

> >> > apply FEAT_LSUI instruction to emulate deprecated swpX instruction.
> >>
> >> Can you explain in the changrelog why you do this?
> >>
> >> In particular, is this a performance optimization or is this required
> >> for correctness in some scenario?
> >
> > I think the main purpose using for this is to "remove the toggling the
> > PSTATE.PAN" bit. so that remove some *potential* problem which can
> > happen when PAN bit is cleared.
>
> Ok, I see. This should definitely be part of the commit
> log for the patch in addition to the cover letter.

Thanks. I'll add detail in next spin after receving other comments.

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--
Sincerely,
Yeoreum Yun