aboutsummaryrefslogtreecommitdiffstats
path: root/arch/x86/include/asm/cmpxchg_32.h
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/include/asm/cmpxchg_32.h')
-rw-r--r--arch/x86/include/asm/cmpxchg_32.h21
1 files changed, 21 insertions, 0 deletions
diff --git a/arch/x86/include/asm/cmpxchg_32.h b/arch/x86/include/asm/cmpxchg_32.h
index 0a7fe0321613..215f5a65790f 100644
--- a/arch/x86/include/asm/cmpxchg_32.h
+++ b/arch/x86/include/asm/cmpxchg_32.h
@@ -42,6 +42,9 @@ static inline void set_64bit(volatile u64 *ptr, u64 value)
#define arch_cmpxchg64_local(ptr, o, n) \
((__typeof__(*(ptr)))__cmpxchg64_local((ptr), (unsigned long long)(o), \
(unsigned long long)(n)))
+#define arch_try_cmpxchg64(ptr, po, n) \
+ __try_cmpxchg64((ptr), (unsigned long long *)(po), \
+ (unsigned long long)(n))
#endif
static inline u64 __cmpxchg64(volatile u64 *ptr, u64 old, u64 new)
@@ -70,6 +73,24 @@ static inline u64 __cmpxchg64_local(volatile u64 *ptr, u64 old, u64 new)
return prev;
}
+static inline bool __try_cmpxchg64(volatile u64 *ptr, u64 *pold, u64 new)
+{
+ bool success;
+ u64 old = *pold;
+ asm volatile(LOCK_PREFIX "cmpxchg8b %[ptr]"
+ CC_SET(z)
+ : CC_OUT(z) (success),
+ [ptr] "+m" (*ptr),
+ "+A" (old)
+ : "b" ((u32)new),
+ "c" ((u32)(new >> 32))
+ : "memory");
+
+ if (unlikely(!success))
+ *pold = old;
+ return success;
+}
+
#ifndef CONFIG_X86_CMPXCHG64
/*
* Building a kernel capable running on 80386 and 80486. It may be necessary