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-rw-r--r--arch/x86/include/asm/cmpxchg.h23
1 files changed, 23 insertions, 0 deletions
diff --git a/arch/x86/include/asm/cmpxchg.h b/arch/x86/include/asm/cmpxchg.h
index 5488e10b9dba..0c9fa2745f13 100644
--- a/arch/x86/include/asm/cmpxchg.h
+++ b/arch/x86/include/asm/cmpxchg.h
@@ -207,4 +207,27 @@ extern void __add_wrong_size(void)
#define add_smp(ptr, inc) __add((ptr), (inc), LOCK_PREFIX)
#define add_sync(ptr, inc) __add((ptr), (inc), "lock; ")
+#define __cmpxchg_double(pfx, p1, p2, o1, o2, n1, n2) \
+({ \
+ bool __ret; \
+ __typeof__(*(p1)) __old1 = (o1), __new1 = (n1); \
+ __typeof__(*(p2)) __old2 = (o2), __new2 = (n2); \
+ BUILD_BUG_ON(sizeof(*(p1)) != sizeof(long)); \
+ BUILD_BUG_ON(sizeof(*(p2)) != sizeof(long)); \
+ VM_BUG_ON((unsigned long)(p1) % (2 * sizeof(long))); \
+ VM_BUG_ON((unsigned long)((p1) + 1) != (unsigned long)(p2)); \
+ asm volatile(pfx "cmpxchg%c4b %2; sete %0" \
+ : "=a" (__ret), "+d" (__old2), \
+ "+m" (*(p1)), "+m" (*(p2)) \
+ : "i" (2 * sizeof(long)), "a" (__old1), \
+ "b" (__new1), "c" (__new2)); \
+ __ret; \
+})
+
+#define cmpxchg_double(p1, p2, o1, o2, n1, n2) \
+ __cmpxchg_double(LOCK_PREFIX, p1, p2, o1, o2, n1, n2)
+
+#define cmpxchg_double_local(p1, p2, o1, o2, n1, n2) \
+ __cmpxchg_double(, p1, p2, o1, o2, n1, n2)
+
#endif /* ASM_X86_CMPXCHG_H */