From: James Morse <[email protected]>
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 <[email protected]>
Reviewed-by: Suzuki K Poulose <[email protected]>
Acked-by: Marc Zyngier <[email protected]>
Signed-off-by: James Morse <[email protected]>
Signed-off-by: Catalin Marinas <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
Signed-off-by: Alex Shi <[email protected]>
---
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;
--
2.7.4