[PATCH v2 5/7] arm64: capabilities: Optimize this_cpu_has_cap
From: Suzuki K Poulose <suzuki.poulose@arm.com>
Date: 2018-11-30 17:18:38
Also in:
lkml
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
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: Vladimiri Murzin <redacted> Tested-by: Vladimiri Murzin <redacted> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> --- arch/arm64/kernel/cpufeature.c | 31 +++++++++---------------------- 1 file changed, 9 insertions(+), 22 deletions(-)
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 6a2563b..618857f 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)
--
2.7.4
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