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SubjectRe: [PATCH v3 10/22] arm64: capabilities: Allow features based on local CPU scope
On Fri, Feb 09, 2018 at 05:54:49PM +0000, Suzuki K Poulose wrote:
> So far we have treated the feature capabilities as system wide
> and this doesn't help with features that could be detected on

doesn't -> wouldn't (since no such features exist yet)

detected to "detected locally" (maybe)

> one or more CPUs (e.g, KPTI, Software prefetch). This patch
> splits the feature detection to two phases :
>
> 1) Local CPU features are checked on all boot time active CPUs.
> 2) System wide features are checked only once after all CPUs are
> active.
>
> Cc: Dave Martin <dave.martin@arm.com>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

Otherwise,

Reviewed-by: Dave Martin <Dave.Martin@arm.com>

> ---
> arch/arm64/kernel/cpufeature.c | 17 +++++++++++------
> 1 file changed, 11 insertions(+), 6 deletions(-)
>
> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index a6e124063e21..45bac0c4ae91 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -551,11 +551,13 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
> }
>
> /*
> - * Run the errata work around checks on the boot CPU, once we have
> - * initialised the cpu feature infrastructure.
> + * Run the errata work around and local feature checks on the
> + * boot CPU, once we have initialised the cpu feature infrastructure.
> */
> update_cpu_capabilities(arm64_errata, SCOPE_LOCAL_CPU,
> "enabling workaround for");
> + update_cpu_capabilities(arm64_features, SCOPE_LOCAL_CPU,
> + "detected feature:");
> }
>
> static void update_cpu_ftr_reg(struct arm64_ftr_reg *reg, u64 new)
> @@ -1411,15 +1413,18 @@ void check_local_cpu_capabilities(void)
>
> /*
> * If we haven't finalised the system capabilities, this CPU gets
> - * a chance to update the errata work arounds.
> + * a chance to update the errata work arounds and local features.
> * Otherwise, this CPU should verify that it has all the system
> * advertised capabilities.
> */
> - if (!sys_caps_initialised)
> + if (!sys_caps_initialised) {
> update_cpu_capabilities(arm64_errata, SCOPE_LOCAL_CPU,
> "enabling workaround for");
> - else
> + update_cpu_capabilities(arm64_features, SCOPE_LOCAL_CPU,
> + "detected feature:");
> + } else {
> verify_local_cpu_capabilities();
> + }
> }
>
> DEFINE_STATIC_KEY_FALSE(arm64_const_caps_ready);
> @@ -1444,7 +1449,7 @@ void __init setup_cpu_features(void)
> int cls;
>
> /* Set the CPU feature capabilies */
> - update_cpu_capabilities(arm64_features, SCOPE_ALL,
> + update_cpu_capabilities(arm64_features, SCOPE_SYSTEM,
> "detected feature:");
> update_cpu_capabilities(arm64_errata, SCOPE_SYSTEM,
> "enabling workaround for");
> --
> 2.14.3
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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