From b1d6b40cbd0d6ff475b6a0a7a807a1e3bee7c033 Mon Sep 17 00:00:00 2001
From: Heiko Carstens <heiko.carstens@de.ibm.com>
Date: Mon, 17 Sep 2012 07:37:13 +0200
Subject: [PATCH] s390/cmpxchg,percpu: implement cmpxchg_double()

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
 arch/s390/Kconfig               |  1 +
 arch/s390/include/asm/cmpxchg.h | 61 +++++++++++++++++++++++++++++++++++++++++
 arch/s390/include/asm/percpu.h  | 22 ++++++++++++++-
 3 files changed, 83 insertions(+), 1 deletion(-)

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 3f42161..e601340 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -96,6 +96,7 @@ config S390
 	select HAVE_MEMBLOCK
 	select HAVE_MEMBLOCK_NODE_MAP
 	select HAVE_CMPXCHG_LOCAL
+	select HAVE_CMPXCHG_DOUBLE
 	select ARCH_DISCARD_MEMBLOCK
 	select BUILDTIME_EXTABLE_SORT
 	select ARCH_INLINE_SPIN_TRYLOCK
diff --git a/arch/s390/include/asm/cmpxchg.h b/arch/s390/include/asm/cmpxchg.h
index 8d798e9..0f636cb 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,
diff --git a/arch/s390/include/asm/percpu.h b/arch/s390/include/asm/percpu.h
index 964e7ee..86fe0ee 100644
--- a/arch/s390/include/asm/percpu.h
+++ b/arch/s390/include/asm/percpu.h
@@ -67,7 +67,7 @@
 #define this_cpu_xor_4(pcp, val) arch_this_cpu_to_op(pcp, val, ^)
 #define this_cpu_xor_8(pcp, val) arch_this_cpu_to_op(pcp, val, ^)
 
-#define arch_this_cpu_cmpxchg(pcp, oval, nval)			\
+#define arch_this_cpu_cmpxchg(pcp, oval, nval)				\
 ({									\
 	typedef typeof(pcp) pcp_op_T__;					\
 	pcp_op_T__ ret__;						\
@@ -108,6 +108,26 @@
 #define this_cpu_xchg_8(pcp, nval) arch_this_cpu_xchg(pcp, nval)
 #endif
 
+#define arch_this_cpu_cmpxchg_double(pcp1, pcp2, o1, o2, n1, n2)	\
+({									\
+	typeof(pcp1) o1__ = (o1), n1__ = (n1);				\
+	typeof(pcp2) o2__ = (o2), n2__ = (n2);				\
+	typeof(pcp1) *p1__;						\
+	typeof(pcp2) *p2__;						\
+	int ret__;							\
+	preempt_disable();						\
+	p1__ = __this_cpu_ptr(&(pcp1));					\
+	p2__ = __this_cpu_ptr(&(pcp2));					\
+	ret__ = __cmpxchg_double(p1__, p2__, o1__, o2__, n1__, n2__);	\
+	preempt_enable();						\
+	ret__;								\
+})
+
+#define this_cpu_cmpxchg_double_4 arch_this_cpu_cmpxchg_double
+#ifdef CONFIG_64BIT
+#define this_cpu_cmpxchg_double_8 arch_this_cpu_cmpxchg_double
+#endif
+
 #include <asm-generic/percpu.h>
 
 #endif /* __ARCH_S390_PERCPU__ */
-- 
2.7.4