arm64: Allow a capability to be checked on a single CPU
Now that the capabilities are only available once all the CPUs have booted, we're unable to check for a particular feature in any subsystem that gets initialized before then. In order to support this, introduce a local_cpu_has_cap() function that tests for the presence of a given capability independently of the whole framework. Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> [ Added preemptible() check ] Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> [will: remove duplicate initialisation of caps in this_cpu_has_cap] Signed-off-by: Will Deacon <will.deacon@arm.com>
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@ -109,6 +109,8 @@ struct arm64_cpu_capabilities {
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extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
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bool this_cpu_has_cap(unsigned int cap);
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static inline bool cpu_have_feature(unsigned int num)
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{
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return elf_hwcap & (1UL << num);
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@ -1010,6 +1010,24 @@ static void __init setup_feature_capabilities(void)
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enable_cpu_capabilities(arm64_features);
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}
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/*
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* Check if the current CPU has a given feature capability.
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* Should be called from non-preemptible context.
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*/
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bool this_cpu_has_cap(unsigned int cap)
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{
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const struct arm64_cpu_capabilities *caps;
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if (WARN_ON(preemptible()))
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return false;
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for (caps = arm64_features; caps->desc; caps++)
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if (caps->capability == cap && caps->matches)
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return caps->matches(caps, SCOPE_LOCAL_CPU);
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return false;
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}
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void __init setup_cpu_features(void)
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{
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u32 cwg;
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