Re: [PATCH v4 4/5] arm64: Verify CPU errata work arounds on hotplugged CPU

From: Catalin Marinas
Date: Fri Apr 22 2016 - 09:41:09 EST


On Fri, Apr 22, 2016 at 12:25:34PM +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.
>
> Cc: Will Deacon <will.deacon@xxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: Andre Przywara <andre.przywara@xxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>

I think Will commented on this previously. Was a decision made to leave
this patch as it is and subsequently add support for enabling local
workarounds for hot-plugged CPUs? I'm fine with this given that most
per-CPU workarounds like undocumented bits are set by firmware. But I'd
like to see it done properly once we have a workaround that needs
per-CPU enabling.

Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>