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| author | Jaccon Bastiaansen <jaccon.bastiaansen@gmail.com> | 2013-05-13 17:28:27 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-05-19 11:38:26 -0700 |
| commit | e374a2ff991dc8b5c10f23849d264373878a9e39 (patch) | |
| tree | 5e2fbeaa57963e81c2298065eaf3034ea9f425c4 /arch | |
| parent | 903bded00704581799e0bd6f4e0dde06a351f9c2 (diff) | |
| download | lwn-e374a2ff991dc8b5c10f23849d264373878a9e39.tar.gz lwn-e374a2ff991dc8b5c10f23849d264373878a9e39.zip | |
ARM: 7720/1: ARM v6/v7 cmpxchg64 shouldn't clear upper 32 bits of the old/new value
commit 6eabb3301b1facee669d9938f7c5a0295c21d71d upstream.
The implementation of cmpxchg64() for the ARM v6 and v7 architecture
casts parameter 2 and 3 (the old and new 64bit values) to an unsigned
long before calling the atomic_cmpxchg64() function. This clears
the top 32 bits of the old and new values, resulting in the wrong
values being compare-exchanged. Luckily, this only appears to be used
for 64-bit sched_clock, which we don't (yet) have on ARM.
This bug was introduced by commit 3e0f5a15f500 ("ARM: 7404/1: cmpxchg64:
use atomic64 and local64 routines for cmpxchg64").
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Jaccon Bastiaansen <jaccon.bastiaansen@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/include/asm/cmpxchg.h | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/arm/include/asm/cmpxchg.h b/arch/arm/include/asm/cmpxchg.h index 7eb18c1d8d6c..4f009c10540d 100644 --- a/arch/arm/include/asm/cmpxchg.h +++ b/arch/arm/include/asm/cmpxchg.h @@ -233,15 +233,15 @@ static inline unsigned long __cmpxchg_local(volatile void *ptr, ((__typeof__(*(ptr)))atomic64_cmpxchg(container_of((ptr), \ atomic64_t, \ counter), \ - (unsigned long)(o), \ - (unsigned long)(n))) + (unsigned long long)(o), \ + (unsigned long long)(n))) #define cmpxchg64_local(ptr, o, n) \ ((__typeof__(*(ptr)))local64_cmpxchg(container_of((ptr), \ local64_t, \ a), \ - (unsigned long)(o), \ - (unsigned long)(n))) + (unsigned long long)(o), \ + (unsigned long long)(n))) #endif /* __LINUX_ARM_ARCH__ >= 6 */ |