From mboxrd@z Thu Jan 1 00:00:00 1970 From: alex.shi@linaro.org (Alex Shi) Date: Thu, 1 Mar 2018 20:53:55 +0800 Subject: [PATCH 18/45] arm64: cpufeature: __this_cpu_has_cap() shouldn't stop early In-Reply-To: <1519908862-11425-1-git-send-email-alex.shi@linaro.org> References: <1519908862-11425-1-git-send-email-alex.shi@linaro.org> Message-ID: <1519908862-11425-19-git-send-email-alex.shi@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: James Morse commit edf298cfce47 upstream. Alex Shi rewrite this commit on func this_cpu_has_cap(). The following commit log is still meaningful. this_cpu_has_cap() tests caps->desc not caps->matches, so it stops walking the list when it finds a 'silent' feature, instead of walking to the end of the list. Prior to v4.6's 644c2ae198412 ("arm64: cpufeature: Test 'matches' pointer to find the end of the list") we always tested desc to find the end of a capability list. This was changed for dubious things like PAN_NOT_UAO. v4.7's e3661b128e53e ("arm64: Allow a capability to be checked on single CPU") added this_cpu_has_cap() using the old desc style test. CC: Suzuki K Poulose Reviewed-by: Suzuki K Poulose Acked-by: Marc Zyngier Signed-off-by: James Morse Signed-off-by: Catalin Marinas Signed-off-by: Will Deacon Signed-off-by: Alex Shi --- arch/arm64/include/asm/futex.h | 1 + arch/arm64/kernel/cpufeature.c | 4 ++-- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/futex.h b/arch/arm64/include/asm/futex.h index 1943cf6..718140a 100644 --- a/arch/arm64/include/asm/futex.h +++ b/arch/arm64/include/asm/futex.h @@ -20,6 +20,7 @@ #include #include +#include #include diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 3a129d4..fcb67e0 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1063,8 +1063,8 @@ bool this_cpu_has_cap(unsigned int cap) if (WARN_ON(preemptible())) return false; - for (caps = arm64_features; caps->desc; caps++) - if (caps->capability == cap && caps->matches) + for (caps = arm64_features; caps->matches; caps++) + if (caps->capability == cap) return caps->matches(caps, SCOPE_LOCAL_CPU); return false; -- 2.7.4