Re: [PATCH 03/17] arm64: Allow checking of a CPU-local erratum

From: Mark Rutland
Date: Mon Mar 20 2017 - 09:57:13 EST


On Mon, Mar 06, 2017 at 11:26:08AM +0000, Marc Zyngier wrote:
> this_cpu_has_cap() only checks the feature array, and not the errata
> one. In order to be able to check for a CPU-local erratum, allow it
> to inspect the latter as well.
>
> This is consistent with cpus_have_cap()'s behaviour, which includes
> errata already.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>

This sounds sensible to me.

Suzuki, any comments?

Thanks,
Mark.

> ---
> arch/arm64/kernel/cpufeature.c | 13 +++++++++++--
> 1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index abda8e861865..6eb77ae99b79 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -1090,20 +1090,29 @@ static void __init setup_feature_capabilities(void)
> * 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)
> +static bool __this_cpu_has_cap(const struct arm64_cpu_capabilities *cap_array,
> + unsigned int cap)
> {
> const struct arm64_cpu_capabilities *caps;
>
> if (WARN_ON(preemptible()))
> return false;
>
> - for (caps = arm64_features; caps->desc; caps++)
> + for (caps = cap_array; caps->desc; caps++)
> if (caps->capability == cap && caps->matches)
> return caps->matches(caps, SCOPE_LOCAL_CPU);
>
> return false;
> }
>
> +extern const struct arm64_cpu_capabilities arm64_errata[];
> +
> +bool this_cpu_has_cap(unsigned int cap)
> +{
> + return (__this_cpu_has_cap(arm64_features, cap) ||
> + __this_cpu_has_cap(arm64_errata, cap));
> +}
> +
> void __init setup_cpu_features(void)
> {
> u32 cwg;
> --
> 2.11.0
>