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SubjectRe: [PATCH v2 07/20] arm64: capabilities: Filter the entries based on a given mask
On Wed, Jan 31, 2018 at 06:27:54PM +0000, Suzuki K Poulose wrote:
> While processing the list of capabilities, it is useful to
> filter out some of the entries based on the given mask for the
> scope of the capabilities to allow better control. This can be
> used later for handling LOCAL vs SYSTEM wide capabilities and more.
> All capabilities should have their scope set to either LOCAL_CPU or
> SYSTEM. No functional/flow change.
>
> Cc: Dave Martin <dave.martin@arm.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> ---
> arch/arm64/include/asm/cpufeature.h | 2 ++
> arch/arm64/kernel/cpufeature.c | 35 ++++++++++++++++++++++++-----------
> 2 files changed, 26 insertions(+), 11 deletions(-)
>
> diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
> index 69b5ce366598..cda62b70d338 100644
> --- a/arch/arm64/include/asm/cpufeature.h
> +++ b/arch/arm64/include/asm/cpufeature.h
> @@ -198,6 +198,8 @@ extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0;
> /* Is it safe for a late CPU to miss this capability when system has it */
> #define ARM64_CPUCAP_OPTIONAL_FOR_LATE_CPU ((u16)BIT(5))
>
> +#define ARM64_CPUCAP_SCOPE_ALL \
> + (ARM64_CPUCAP_SCOPE_LOCAL_CPU | ARM64_CPUCAP_SCOPE_SYSTEM)

Perhaps we could just use _MASK rather than having a separate #define,
but it's good either way.

Is there a situation in which _ALL and _MASK would need to be
different?

> /*
> * CPU errata detected at boot time based on feature of one or more CPUs.
> * It is not safe for a late CPU to have this feature when the system doesn't
> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index 5e4d581c97f1..5163dc51b975 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -1185,10 +1185,12 @@ static bool __this_cpu_has_cap(const struct arm64_cpu_capabilities *cap_array,
> }
>
> static void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
> - const char *info)
> + u16 scope_mask, const char *info)
> {
> + scope_mask &= ARM64_CPUCAP_SCOPE_MASK;
> for (; caps->matches; caps++) {
> - if (!caps->matches(caps, cpucap_default_scope(caps)))
> + if (!(caps->type & scope_mask) ||
> + !caps->matches(caps, cpucap_default_scope(caps)))
> continue;
>
> if (!cpus_have_cap(caps->capability) && caps->desc)
> @@ -1210,12 +1212,14 @@ static int __enable_cpu_capability(void *arg)
> * Run through the enabled capabilities and enable() it on all active
> * CPUs
> */
> -static void __init enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps)
> +static void __init
> +enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps, u16 scope_mask)
> {
> + scope_mask &= ARM64_CPUCAP_SCOPE_MASK;
> for (; caps->matches; caps++) {
> unsigned int num = caps->capability;
>
> - if (!cpus_have_cap(num))
> + if (!(caps->type & scope_mask) || !cpus_have_cap(num))
> continue;
>
> /* Ensure cpus_have_const_cap(num) works */
> @@ -1240,12 +1244,18 @@ static void __init enable_cpu_capabilities(const struct arm64_cpu_capabilities *
> *
> * Returns "false" on conflicts.
> */
> -static bool __verify_local_cpu_caps(const struct arm64_cpu_capabilities *caps_list)
> +static bool __verify_local_cpu_caps(const struct arm64_cpu_capabilities *caps_list,
> + u16 scope_mask)
> {
> bool cpu_has_cap, system_has_cap;
> const struct arm64_cpu_capabilities *caps = caps_list;
>
> + scope_mask &= ARM64_CPUCAP_SCOPE_MASK;
> for (; caps->matches; caps++) {
> +

Nit: extra blank line?

[...]

With that fixed,

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

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