diff options
author | Catalin Marinas <catalin.marinas@arm.com> | 2016-09-05 18:25:48 +0100 |
---|---|---|
committer | Will Deacon <will.deacon@arm.com> | 2016-09-07 09:41:42 +0100 |
commit | efd9e03facd075f5b76bf82e6c785bd45d5cbf4f (patch) | |
tree | f271f509acaba940a50d978a14713585f34b8667 /arch/arm64/include/asm/cpufeature.h | |
parent | ef0da55a84a345f323ceddda3b6c78b25de90435 (diff) | |
download | op-kernel-dev-efd9e03facd075f5b76bf82e6c785bd45d5cbf4f.zip op-kernel-dev-efd9e03facd075f5b76bf82e6c785bd45d5cbf4f.tar.gz |
arm64: Use static keys for CPU features
This patch adds static keys transparently for all the cpu_hwcaps
features by implementing an array of default-false static keys and
enabling them when detected. The cpus_have_cap() check uses the static
keys if the feature being checked is a constant, otherwise the compiler
generates the bitmap test.
Because of the early call to static_branch_enable() via
check_local_cpu_errata() -> update_cpu_capabilities(), the jump labels
are initialised in cpuinfo_store_boot_cpu().
Cc: Will Deacon <will.deacon@arm.com>
Cc: Suzuki K. Poulose <Suzuki.Poulose@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/cpufeature.h')
-rw-r--r-- | arch/arm64/include/asm/cpufeature.h | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index c07c5d1..23a76dc5 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -9,6 +9,8 @@ #ifndef __ASM_CPUFEATURE_H #define __ASM_CPUFEATURE_H +#include <linux/jump_label.h> + #include <asm/hwcap.h> #include <asm/sysreg.h> @@ -110,6 +112,7 @@ struct arm64_cpu_capabilities { }; extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS); +extern struct static_key_false cpu_hwcap_keys[ARM64_NCAPS]; bool this_cpu_has_cap(unsigned int cap); @@ -122,16 +125,21 @@ static inline bool cpus_have_cap(unsigned int num) { if (num >= ARM64_NCAPS) return false; - return test_bit(num, cpu_hwcaps); + if (__builtin_constant_p(num)) + return static_branch_unlikely(&cpu_hwcap_keys[num]); + else + return test_bit(num, cpu_hwcaps); } static inline void cpus_set_cap(unsigned int num) { - if (num >= ARM64_NCAPS) + if (num >= ARM64_NCAPS) { pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n", num, ARM64_NCAPS); - else + } else { __set_bit(num, cpu_hwcaps); + static_branch_enable(&cpu_hwcap_keys[num]); + } } static inline int __attribute_const__ |