1 files changed, 37 insertions, 0 deletions
diff --git a/include/asm-x86/cmpxchg_64.h b/include/asm-x86/cmpxchg_64.h
index d9b26b9a28cf..17463ccf8166 100644
--- a/include/asm-x86/cmpxchg_64.h
+++ b/include/asm-x86/cmpxchg_64.h
@@ -93,6 +93,39 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
        return old;
 }
+/*
+ * Always use locked operations when touching memory shared with a
+ * hypervisor, since the system may be SMP even if the guest kernel
+ * isn't.
+ */
+static inline unsigned long __sync_cmpxchg(volatile void *ptr,
+                                           unsigned long old,
+                                           unsigned long new, int size)
+{
+        unsigned long prev;
+        switch (size) {
+        case 1:
+                asm volatile("lock; cmpxchgb %b1,%2"
+                             : "=a"(prev)
+                             : "q"(new), "m"(*__xg(ptr)), "0"(old)
+                             : "memory");
+                return prev;
+        case 2:
+                asm volatile("lock; cmpxchgw %w1,%2"
+                             : "=a"(prev)
+                             : "r"(new), "m"(*__xg(ptr)), "0"(old)
+                             : "memory");
+                return prev;
+        case 4:
+                asm volatile("lock; cmpxchgl %1,%2"
+                             : "=a"(prev)
+                             : "r"(new), "m"(*__xg(ptr)), "0"(old)
+                             : "memory");
+                return prev;
+        }
+        return old;
+}
 static inline unsigned long __cmpxchg_local(volatile void *ptr,
                                            unsigned long old,
                                            unsigned long new, int size)
@@ -139,6 +172,10 @@ static inline unsigned long __cmpxchg_local(volatile void *ptr,
        ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
                                             (unsigned long)(n),        \
                                             sizeof(*(ptr))))
+#define sync_cmpxchg(ptr, o, n)                                         \
+        ((__typeof__(*(ptr)))__sync_cmpxchg((ptr), (unsigned long)(o),  \
+                                            (unsigned long)(n),         \
+                                            sizeof(*(ptr))))
 #define cmpxchg64_local(ptr, o, n)                                      \
 ({                                                                      \
        BUILD_BUG_ON(sizeof(*(ptr)) != 8);                              \

diff --git a/include/asm-x86/cmpxchg_64.h b/include/asm-x86/cmpxchg_64.h index d9b26b9a28cf..17463ccf8166 100644 --- a/include/asm-x86/cmpxchg_64.h +++ b/include/asm-x86/cmpxchg_64.h
@@ -93,6 +93,39 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
93	return old;	93	return old;
94	}	94	}
95		95
		96	/*
		97	* Always use locked operations when touching memory shared with a
		98	* hypervisor, since the system may be SMP even if the guest kernel
		99	* isn't.
		100	*/
		101	static inline unsigned long __sync_cmpxchg(volatile void *ptr,
		102	unsigned long old,
		103	unsigned long new, int size)
		104	{
		105	unsigned long prev;
		106	switch (size) {
		107	case 1:
		108	asm volatile("lock; cmpxchgb %b1,%2"
		109	: "=a"(prev)
		110	: "q"(new), "m"(*__xg(ptr)), "0"(old)
		111	: "memory");
		112	return prev;
		113	case 2:
		114	asm volatile("lock; cmpxchgw %w1,%2"
		115	: "=a"(prev)
		116	: "r"(new), "m"(*__xg(ptr)), "0"(old)
		117	: "memory");
		118	return prev;
		119	case 4:
		120	asm volatile("lock; cmpxchgl %1,%2"
		121	: "=a"(prev)
		122	: "r"(new), "m"(*__xg(ptr)), "0"(old)
		123	: "memory");
		124	return prev;
		125	}
		126	return old;
		127	}
		128
96	static inline unsigned long __cmpxchg_local(volatile void *ptr,	129	static inline unsigned long __cmpxchg_local(volatile void *ptr,
97	unsigned long old,	130	unsigned long old,
98	unsigned long new, int size)	131	unsigned long new, int size)
@@ -139,6 +172,10 @@ static inline unsigned long __cmpxchg_local(volatile void *ptr,
139	((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \	172	((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
140	(unsigned long)(n), \	173	(unsigned long)(n), \
141	sizeof(*(ptr))))	174	sizeof(*(ptr))))
		175	#define sync_cmpxchg(ptr, o, n) \
		176	((__typeof__(*(ptr)))__sync_cmpxchg((ptr), (unsigned long)(o), \
		177	(unsigned long)(n), \
		178	sizeof(*(ptr))))
142	#define cmpxchg64_local(ptr, o, n) \	179	#define cmpxchg64_local(ptr, o, n) \
143	({ \	180	({ \
144	BUILD_BUG_ON(sizeof(*(ptr)) != 8); \	181	BUILD_BUG_ON(sizeof(*(ptr)) != 8); \