From: James Morse james.morse@arm.com
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 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: Will Deacon will.deacon@arm.com
Signed-off-by: Alex Shi alex.shi@linaro.org --- 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 <linux/futex.h> #include <linux/uaccess.h> +#include <linux/compiler.h>
#include <asm/errno.h>
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;