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Re: [PATCH 1/5] arm64: cpufeature: Add scope for capability check

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On Thu, Apr 14, 2016 at 06:47:46PM +0100, Suzuki K Poulose wrote:
> On 14/04/16 18:38, Will Deacon wrote:
> >Hi Suzuki,
> >
> >On Wed, Apr 06, 2016 at 12:24:10PM +0100, Suzuki K Poulose wrote:
> >>Add scope parameter to the arm64_cpu_capabilities::matches(),
> >>so that this can be reused for checking the capability on a
> >>given CPU vs the system wide. By default, the system uses
> >>'system' wide values for setting the CPU_HWCAPs and ELF_HWCAPs.
> 
> >>  static bool __maybe_unused
> >>-is_affected_midr_range(const struct arm64_cpu_capabilities *entry)
> >>+is_affected_midr_range(const struct arm64_cpu_capabilities *entry, int __unused)
> >
> >Maybe it would be better to WARN if somebody passes SCOPE_SYSTEM, rather
> >than silently treat it as per-cpu?
> 
> Should we worry about errata's which may not necessarily depend on per CPU or
> a local capability (GIC) ?

Why would they be calling is_affected_midr_range?

> If not, we could add a WARN after passing down LOCAL
> scope for errata.

But if we don't care about errata that aren't local, then why would we warn
on LOCAL?

> Right now we always do SCOPE_SYSTEM from update_cpu_capabilities(), even for
> cpu_errata table. There is no specific reason for that.

I'm totally confused. Can you define SCOPE_SYSTEM and SCOPE_LOCAL for me,
please?

Will

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[PATCH 0/5] arm64: Fix behavior of maxcpus=n Suzuki K Poulose <suzuki.poulose@arm.com> - 2016-04-06 13:30 +0200
  [PATCH 1/5] arm64: cpufeature: Add scope for capability check Suzuki K Poulose <suzuki.poulose@arm.com> - 2016-04-06 13:30 +0200
    Re: [PATCH 1/5] arm64: cpufeature: Add scope for capability check Will Deacon <will.deacon@arm.com> - 2016-04-14 19:40 +0200
      Re: [PATCH 1/5] arm64: cpufeature: Add scope for capability check Suzuki K Poulose <Suzuki.Poulose@arm.com> - 2016-04-14 19:50 +0200
        Re: [PATCH 1/5] arm64: cpufeature: Add scope for capability check Will Deacon <will.deacon@arm.com> - 2016-04-15 15:00 +0200
          Re: [PATCH 1/5] arm64: cpufeature: Add scope for capability check Suzuki K Poulose <Suzuki.Poulose@arm.com> - 2016-04-15 15:30 +0200
  [PATCH 3/5] irqchip/gic: Restore CPU interface checking Suzuki K Poulose <suzuki.poulose@arm.com> - 2016-04-06 13:30 +0200

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