Re: [PATCH v4 2/5] arm64: Allow a capability to be checked on a single CPU

From	Catalin Marinas <catalin.marinas@arm.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v4 2/5] arm64: Allow a capability to be checked on a single CPU
Date	2016-04-22 15:40 +0200
Message-ID	<rqJto-2Ga-11@gated-at.bofh.it> (permalink)
References	<rqHrz-1aV-3@gated-at.bofh.it> <rqHrB-1aV-53@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Fri, Apr 22, 2016 at 12:25:32PM +0100, Suzuki K. Poulose wrote:
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -1005,6 +1005,24 @@ static void __init setup_feature_capabilities(void)
>  	enable_cpu_capabilities(arm64_features);
>  }
>  
> +/*
> + * Check if the current CPU has a given feature capability.
> + * Should be called from non-preemptible context.
> + */
> +bool this_cpu_has_cap(unsigned int cap)
> +{
> +	const struct arm64_cpu_capabilities *caps = arm64_features;
> +
> +	if (WARN_ON(preemptible()))
> +		return false;
> +
> +	for (caps = arm64_features; caps->desc; caps++)
> +		if (caps->capability == cap && caps->matches)
> +			return caps->matches(caps, SCOPE_LOCAL_CPU);

Nitpick: you don't need to initialise "caps" twice.

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

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[PATCH v4 0/5] arm64: Fix behavior of maxcpus=n Suzuki K Poulose <suzuki.poulose@arm.com> - 2016-04-22 13:30 +0200
  [PATCH v4 3/5] irqchip/gic: Restore CPU interface checking Suzuki K Poulose <suzuki.poulose@arm.com> - 2016-04-22 13:30 +0200
    Re: [PATCH v4 3/5] irqchip/gic: Restore CPU interface checking Catalin Marinas <catalin.marinas@arm.com> - 2016-04-22 15:40 +0200
  [PATCH v4 1/5] arm64: cpufeature: Add scope for capability check Suzuki K Poulose <suzuki.poulose@arm.com> - 2016-04-22 13:30 +0200
    Re: [PATCH v4 1/5] arm64: cpufeature: Add scope for capability check Catalin Marinas <catalin.marinas@arm.com> - 2016-04-22 15:40 +0200
  [PATCH v4 2/5] arm64: Allow a capability to be checked on a single CPU Suzuki K Poulose <suzuki.poulose@arm.com> - 2016-04-22 13:30 +0200
    Re: [PATCH v4 2/5] arm64: Allow a capability to be checked on a  single CPU Catalin Marinas <catalin.marinas@arm.com> - 2016-04-22 15:40 +0200

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