[PATCHv6 6/8] arm64: use fixmap for text patching when text is RO

Laura Abbott lauraa at codeaurora.org
Tue Nov 25 10:54:14 PST 2014


On 11/25/2014 9:04 AM, Mark Rutland wrote:
> Hi Laura,
>
> It looks like "early" means before we've set up the strict page
> permissions, though as far as I can tell the fixmap will already be
> available before we do any patching. Could we not always use the fixmap
> for patching? Then we only need the patch_{map,unmap} additions, and not
> the changes to distinguish the early cases.
>
>  From testing on Juno with defconfig, all of the early patches were
> avoidable NOP -> NOP changes as part of static key initialisation, which
> I think we can skip similarly to x86 (I'll send a patch shortly). All other
> patches were not early and went via the fixmap.
>
> Even with the avoidable NOP -> NOP patching I did not see a noticeable
> boot time difference from forcing the use of the fixmap.
>

I was basing it off of the arm version which needed the early option.
If arm64 doesn't need it I'll drop it.

> Thanks,
> Mark.
>

Thanks,
Laura

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