1 files changed, 61 insertions, 0 deletions
diff --git a/arch/s390/include/asm/cmpxchg.h b/arch/s390/include/asm/cmpxchg.h
index 8d798e962b6..0f636cbdf34 100644
--- a/arch/s390/include/asm/cmpxchg.h
+++ b/arch/s390/include/asm/cmpxchg.h
@@ -7,7 +7,9 @@
 #ifndef __ASM_CMPXCHG_H
 #define __ASM_CMPXCHG_H
 
+#include <linux/mmdebug.h>
 #include <linux/types.h>
+#include <linux/bug.h>
 
 extern void __xchg_called_with_bad_pointer(void);
 
@@ -203,6 +205,65 @@ static inline unsigned long long __cmpxchg64(void *ptr,
 })
 #endif /* CONFIG_64BIT */
 
+#define __cmpxchg_double_op(p1, p2, o1, o2, n1, n2, insn)		\
+({									\
+	register __typeof__(*(p1)) __old1 asm("2") = (o1);		\
+	register __typeof__(*(p2)) __old2 asm("3") = (o2);		\
+	register __typeof__(*(p1)) __new1 asm("4") = (n1);		\
+	register __typeof__(*(p2)) __new2 asm("5") = (n2);		\
+	int cc;								\
+	asm volatile(							\
+			insn   " %[old],%[new],%[ptr]\n"		\
+		"	ipm	%[cc]\n"				\
+		"	srl	%[cc],28"				\
+		: [cc] "=d" (cc), [old] "+d" (__old1), "+d" (__old2)	\
+		: [new] "d" (__new1), "d" (__new2),			\
+		  [ptr] "Q" (*(p1)), "Q" (*(p2))			\
+		: "memory", "cc");					\
+	!cc;								\
+})
+
+#define __cmpxchg_double_4(p1, p2, o1, o2, n1, n2) \
+	__cmpxchg_double_op(p1, p2, o1, o2, n1, n2, "cds")
+
+#define __cmpxchg_double_8(p1, p2, o1, o2, n1, n2) \
+	__cmpxchg_double_op(p1, p2, o1, o2, n1, n2, "cdsg")
+
+extern void __cmpxchg_double_called_with_bad_pointer(void);
+
+#define __cmpxchg_double(p1, p2, o1, o2, n1, n2)			\
+({									\
+	int __ret;							\
+	switch (sizeof(*(p1))) {					\
+	case 4:								\
+		__ret = __cmpxchg_double_4(p1, p2, o1, o2, n1, n2);	\
+		break;							\
+	case 8:								\
+		__ret = __cmpxchg_double_8(p1, p2, o1, o2, n1, n2);	\
+		break;							\
+	default:							\
+		__cmpxchg_double_called_with_bad_pointer();		\
+	}								\
+	__ret;								\
+})
+
+#define cmpxchg_double(p1, p2, o1, o2, n1, n2)				\
+({									\
+	__typeof__(p1) __p1 = (p1);					\
+	__typeof__(p2) __p2 = (p2);					\
+	int __ret;							\
+	BUILD_BUG_ON(sizeof(*(p1)) != sizeof(long));			\
+	BUILD_BUG_ON(sizeof(*(p2)) != sizeof(long));			\
+	VM_BUG_ON((unsigned long)((__p1) + 1) != (unsigned long)(__p2));\
+	if (sizeof(long) == 4)						\
+		__ret = __cmpxchg_double_4(__p1, __p2, o1, o2, n1, n2);	\
+	else								\
+		__ret = __cmpxchg_double_8(__p1, __p2, o1, o2, n1, n2);	\
+	__ret;								\
+})
+
+#define system_has_cmpxchg_double()	1
+
 #include <asm-generic/cmpxchg-local.h>
 
 static inline unsigned long __cmpxchg_local(void *ptr,