1 files changed, 66 insertions, 1 deletions
diff --git a/arch/x86/include/asm/cmpxchg_64.h b/arch/x86/include/asm/cmpxchg_64.h
index 0d3beb27b7fe..44b08b53ab32 100644
--- a/arch/x86/include/asm/cmpxchg_64.h
+++ b/arch/x86/include/asm/cmpxchg_64.h
@@ -20,6 +20,71 @@
 	arch_try_cmpxchg((ptr), (po), (n));				\
 })
 
-#define system_has_cmpxchg_double() boot_cpu_has(X86_FEATURE_CX16)
+union __u128_halves {
+	u128 full;
+	struct {
+		u64 low, high;
+	};
+};
+
+#define __arch_cmpxchg128(_ptr, _old, _new, _lock)			\
+({									\
+	union __u128_halves o = { .full = (_old), },			\
+			    n = { .full = (_new), };			\
+									\
+	asm volatile(_lock "cmpxchg16b %[ptr]"				\
+		     : [ptr] "+m" (*(_ptr)),				\
+		       "+a" (o.low), "+d" (o.high)			\
+		     : "b" (n.low), "c" (n.high)			\
+		     : "memory");					\
+									\
+	o.full;								\
+})
+
+static __always_inline u128 arch_cmpxchg128(volatile u128 *ptr, u128 old, u128 new)
+{
+	return __arch_cmpxchg128(ptr, old, new, LOCK_PREFIX);
+}
+#define arch_cmpxchg128 arch_cmpxchg128
+
+static __always_inline u128 arch_cmpxchg128_local(volatile u128 *ptr, u128 old, u128 new)
+{
+	return __arch_cmpxchg128(ptr, old, new,);
+}
+#define arch_cmpxchg128_local arch_cmpxchg128_local
+
+#define __arch_try_cmpxchg128(_ptr, _oldp, _new, _lock)			\
+({									\
+	union __u128_halves o = { .full = *(_oldp), },			\
+			    n = { .full = (_new), };			\
+	bool ret;							\
+									\
+	asm volatile(_lock "cmpxchg16b %[ptr]"				\
+		     CC_SET(e)						\
+		     : CC_OUT(e) (ret),					\
+		       [ptr] "+m" (*ptr),				\
+		       "+a" (o.low), "+d" (o.high)			\
+		     : "b" (n.low), "c" (n.high)			\
+		     : "memory");					\
+									\
+	if (unlikely(!ret))						\
+		*(_oldp) = o.full;					\
+									\
+	likely(ret);							\
+})
+
+static __always_inline bool arch_try_cmpxchg128(volatile u128 *ptr, u128 *oldp, u128 new)
+{
+	return __arch_try_cmpxchg128(ptr, oldp, new, LOCK_PREFIX);
+}
+#define arch_try_cmpxchg128 arch_try_cmpxchg128
+
+static __always_inline bool arch_try_cmpxchg128_local(volatile u128 *ptr, u128 *oldp, u128 new)
+{
+	return __arch_try_cmpxchg128(ptr, oldp, new,);
+}
+#define arch_try_cmpxchg128_local arch_try_cmpxchg128_local
+
+#define system_has_cmpxchg128()		boot_cpu_has(X86_FEATURE_CX16)
 
 #endif /* _ASM_X86_CMPXCHG_64_H */