From: Suzuki K Poulose <suzuki.poulose@arm.com> mainline inclusion from v5.0-rc1 commit f7bfc14a0819 category: feature bugzilla: 27615 CVE: NA ------------------------------------------------- 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> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> Reviewed-by: Hanjun Guo <guohanjun@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.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 98c32a9035d45..30dd8f97bd9f4 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1806,25 +1806,6 @@ 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) { @@ -2077,10 +2058,16 @@ 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) -- 2.25.1