Re: [PATCH 4/5] arm64: Verify CPU errata work arounds on hotplugged CPU

From: Will Deacon
Date: Fri Apr 15 2016 - 10:12:48 EST


On Fri, Apr 15, 2016 at 03:10:27PM +0100, Suzuki K Poulose wrote:
> On 14/04/16 18:49, Suzuki K Poulose wrote:
> >On 14/04/16 18:39, Will Deacon wrote:
> >>On Wed, Apr 06, 2016 at 12:24:13PM +0100, Suzuki K Poulose wrote:
> >>>CPU Errata work arounds are detected and applied to the
> >>>kernel code at boot time and the data is then freed up.
> >>>If a new hotplugged CPU requires a work around which
> >>>was not applied at boot time, there is nothing we can
> >>>do but simply fail the booting.
> >>
> >>Hmm, wouldn't it be better not to free the alternative text for errata
> >>workarounds instead?
> >
> >We could. I don't have a strong opinion. If there are no objections, I could
> >adopt it.
>
> The alternatives have been merged to .init by :
>
> commit 9aa4ec1571da6236 ("arm64: mm: fold alternatives into .init")
>
> Mark,
>
> Do you have any concerns on applying alternatives for CPUs turned online later ?
> We have to revert the patch above to get going

Well, note that I'm only suggesting that we keep the alternatives for
CPU errata workarounds.

Will