diff options
| author |   Suzuki K Poulose <suzuki.poulose@arm.com> | 2018-11-30 17:18:04 +0000 |
|---|---|---|
| committer |   Will Deacon <will.deacon@arm.com> | 2018-12-06 15:12:25 +0000 |
| commit | f7bfc14a0819962bc0767f33ce17d4b366b46dd6 (patch) | |
| tree | ecf7354be09bed5586c633200adfb3e356db2e17 | |
| parent | arm64: capabilities: Speed up capability lookup (diff) | |
| download | linux-dev-f7bfc14a0819962bc0767f33ce17d4b366b46dd6.tar.xz linux-dev-f7bfc14a0819962bc0767f33ce17d4b366b46dd6.zip | |
arm64: capabilities: Optimize this_cpu_has_cap
Make use of the sorted capability list to access the capability
entry in this_cpu_has_cap() to avoid iterating over the two
tables.
Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
| -rw-r--r-- | arch/arm64/kernel/cpufeature.c | 31 |
1 files changed, 9 insertions, 22 deletions
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 6e715c6d4994..6e9875c0a4cb 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1512,25 +1512,6 @@ static void __init setup_elf_hwcaps(const struct arm64_cpu_capabilities *hwcaps) cap_set_elf_hwcap(hwcaps); } -/* - * Check if the current CPU has a given feature capability. - * Should be called from non-preemptible context. - */ -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 = cap_array; caps->matches; caps++) - if (caps->capability == cap) - return caps->matches(caps, SCOPE_LOCAL_CPU); - - return false; -} - static void __update_cpu_capabilities(const struct arm64_cpu_capabilities *caps, u16 scope_mask, const char *info) { @@ -1780,10 +1761,16 @@ static void __init mark_const_caps_ready(void) static_branch_enable(&arm64_const_caps_ready); } -bool this_cpu_has_cap(unsigned int cap) +bool this_cpu_has_cap(unsigned int n) { - return (__this_cpu_has_cap(arm64_features, cap) || - __this_cpu_has_cap(arm64_errata, cap)); + if (!WARN_ON(preemptible()) && n < ARM64_NCAPS) { + const struct arm64_cpu_capabilities *cap = cpu_hwcaps_ptrs[n]; + + if (cap) + return cap->matches(cap, SCOPE_LOCAL_CPU); + } + + return false; } static void __init setup_system_capabilities(void) |