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From: Will Deacon <will.deacon@arm.com>
To: Suzuki K Poulose <Suzuki.Poulose@arm.com>
Cc: linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, marc.zyngier@arm.com,
	catalin.marinas@arm.com, mark.rutland@arm.com,
	Vadim.Lomovtsev@caviumnetworks.com,
	James Morse <james.morse@arm.com>,
	Andre Przywara <andre.przywara@arm.com>
Subject: Re: [PATCH 1/5] arm64: cpufeature: Add scope for capability check
Date: Fri, 15 Apr 2016 13:55:12 +0100	[thread overview]
Message-ID: <20160415125511.GF22906@arm.com> (raw)
In-Reply-To: <570FD7C2.9030305@arm.com>

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

  reply	other threads:[~2016-04-15 12:55 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-06 11:24 [PATCH 0/5] arm64: Fix behavior of maxcpus=n Suzuki K Poulose
2016-04-06 11:24 ` [PATCH 1/5] arm64: cpufeature: Add scope for capability check Suzuki K Poulose
2016-04-14 17:38   ` Will Deacon
2016-04-14 17:47     ` Suzuki K Poulose
2016-04-15 12:55       ` Will Deacon [this message]
2016-04-15 13:26         ` Suzuki K Poulose
2016-04-06 11:24 ` [PATCH 2/5] arm64: Allow a capability to be checked on a single CPU Suzuki K Poulose
2016-04-06 11:24 ` [PATCH 3/5] irqchip/gic: Restore CPU interface checking Suzuki K Poulose
2016-04-06 11:24 ` [PATCH 4/5] arm64: Verify CPU errata work arounds on hotplugged CPU Suzuki K Poulose
2016-04-14 17:39   ` Will Deacon
2016-04-14 17:49     ` Suzuki K Poulose
2016-04-15 14:10       ` Suzuki K Poulose
2016-04-15 14:12         ` Will Deacon
2016-04-18 13:41           ` Suzuki K Poulose
2016-04-06 11:24 ` [PATCH 5/5] arm64: Fix behavior of maxcpus=N Suzuki K Poulose
2016-04-07  9:18   ` James Morse
2016-04-07  9:26     ` Suzuki K Poulose
2016-04-07 10:07     ` [UPDATED] " Suzuki K Poulose

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