From: Jaccon Bastiaansen Date: Mon, 13 May 2013 16:28:27 +0000 (+0100) Subject: ARM: 7720/1: ARM v6/v7 cmpxchg64 shouldn't clear upper 32 bits of the old/new value X-Git-Tag: v3.10-rc2~27^2 X-Git-Url: http://git.cascardo.info/?a=commitdiff_plain;h=6eabb3301b1facee669d9938f7c5a0295c21d71d;p=cascardo%2Flinux.git ARM: 7720/1: ARM v6/v7 cmpxchg64 shouldn't clear upper 32 bits of the old/new value 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"). Cc: Acked-by: Will Deacon Signed-off-by: Jaccon Bastiaansen Signed-off-by: Russell King --- 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 */