From: James Morse james.morse@arm.com
commit edf298cfce47ab7279d03b5203ae2ef3a58e49db upstream.
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 suzuki.poulose@arm.com Reviewed-by: Suzuki K Poulose suzuki.poulose@arm.com Acked-by: Marc Zyngier marc.zyngier@arm.com Signed-off-by: James Morse james.morse@arm.com Signed-off-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Mark Rutland mark.rutland@arm.com [v4.9 backport] --- arch/arm64/kernel/cpufeature.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 5056fc597ae9..cf000fd694fa 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1024,9 +1024,8 @@ static bool __this_cpu_has_cap(const struct arm64_cpu_capabilities *cap_array, if (WARN_ON(preemptible())) return false;
- for (caps = cap_array; caps->desc; caps++) + for (caps = cap_array; caps->matches; caps++) if (caps->capability == cap && - caps->matches && caps->matches(caps, SCOPE_LOCAL_CPU)) return true; return false;