[S390] xchg/cmpxchg: move to own header file

Move xchg() and cmpxchg() functions to own header file like some
other architectures have done.
With this we make sure that system.h now really looks like a place
where everything is gathered that doesn't fit anywhere else.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/include/asm/cmpxchg.h

@@ -0,0 +1,205 @@
+/*
+ * Copyright IBM Corp. 1999, 2011
+ *
+ * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
+ */
+
+#ifndef __ASM_CMPXCHG_H
+#define __ASM_CMPXCHG_H
+
+#include <linux/types.h>
+
+extern void __xchg_called_with_bad_pointer(void);
+
+static inline unsigned long __xchg(unsigned long x, void *ptr, int size)
+{
+	unsigned long addr, old;
+	int shift;
+
+	switch (size) {
+	case 1:
+		addr = (unsigned long) ptr;
+		shift = (3 ^ (addr & 3)) << 3;
+		addr ^= addr & 3;
+		asm volatile(
+			"	l	%0,%4\n"
+			"0:	lr	0,%0\n"
+			"	nr	0,%3\n"
+			"	or	0,%2\n"
+			"	cs	%0,0,%4\n"
+			"	jl	0b\n"
+			: "=&d" (old), "=Q" (*(int *) addr)
+			: "d" (x << shift), "d" (~(255 << shift)),
+			  "Q" (*(int *) addr) : "memory", "cc", "0");
+		return old >> shift;
+	case 2:
+		addr = (unsigned long) ptr;
+		shift = (2 ^ (addr & 2)) << 3;
+		addr ^= addr & 2;
+		asm volatile(
+			"	l	%0,%4\n"
+			"0:	lr	0,%0\n"
+			"	nr	0,%3\n"
+			"	or	0,%2\n"
+			"	cs	%0,0,%4\n"
+			"	jl	0b\n"
+			: "=&d" (old), "=Q" (*(int *) addr)
+			: "d" (x << shift), "d" (~(65535 << shift)),
+			  "Q" (*(int *) addr) : "memory", "cc", "0");
+		return old >> shift;
+	case 4:
+		asm volatile(
+			"	l	%0,%3\n"
+			"0:	cs	%0,%2,%3\n"
+			"	jl	0b\n"
+			: "=&d" (old), "=Q" (*(int *) ptr)
+			: "d" (x), "Q" (*(int *) ptr)
+			: "memory", "cc");
+		return old;
+#ifdef CONFIG_64BIT
+	case 8:
+		asm volatile(
+			"	lg	%0,%3\n"
+			"0:	csg	%0,%2,%3\n"
+			"	jl	0b\n"
+			: "=&d" (old), "=m" (*(long *) ptr)
+			: "d" (x), "Q" (*(long *) ptr)
+			: "memory", "cc");
+		return old;
+#endif /* CONFIG_64BIT */
+	}
+	__xchg_called_with_bad_pointer();
+	return x;
+}
+
+#define xchg(ptr, x)							  \
+({									  \
+	__typeof__(*(ptr)) __ret;					  \
+	__ret = (__typeof__(*(ptr)))					  \
+		__xchg((unsigned long)(x), (void *)(ptr), sizeof(*(ptr)));\
+	__ret;								  \
+})
+
+/*
+ * Atomic compare and exchange.	 Compare OLD with MEM, if identical,
+ * store NEW in MEM.  Return the initial value in MEM.	Success is
+ * indicated by comparing RETURN with OLD.
+ */
+
+#define __HAVE_ARCH_CMPXCHG
+
+extern void __cmpxchg_called_with_bad_pointer(void);
+
+static inline unsigned long __cmpxchg(void *ptr, unsigned long old,
+				      unsigned long new, int size)
+{
+	unsigned long addr, prev, tmp;
+	int shift;
+
+	switch (size) {
+	case 1:
+		addr = (unsigned long) ptr;
+		shift = (3 ^ (addr & 3)) << 3;
+		addr ^= addr & 3;
+		asm volatile(
+			"	l	%0,%2\n"
+			"0:	nr	%0,%5\n"
+			"	lr	%1,%0\n"
+			"	or	%0,%3\n"
+			"	or	%1,%4\n"
+			"	cs	%0,%1,%2\n"
+			"	jnl	1f\n"
+			"	xr	%1,%0\n"
+			"	nr	%1,%5\n"
+			"	jnz	0b\n"
+			"1:"
+			: "=&d" (prev), "=&d" (tmp), "=Q" (*(int *) ptr)
+			: "d" (old << shift), "d" (new << shift),
+			  "d" (~(255 << shift)), "Q" (*(int *) ptr)
+			: "memory", "cc");
+		return prev >> shift;
+	case 2:
+		addr = (unsigned long) ptr;
+		shift = (2 ^ (addr & 2)) << 3;
+		addr ^= addr & 2;
+		asm volatile(
+			"	l	%0,%2\n"
+			"0:	nr	%0,%5\n"
+			"	lr	%1,%0\n"
+			"	or	%0,%3\n"
+			"	or	%1,%4\n"
+			"	cs	%0,%1,%2\n"
+			"	jnl	1f\n"
+			"	xr	%1,%0\n"
+			"	nr	%1,%5\n"
+			"	jnz	0b\n"
+			"1:"
+			: "=&d" (prev), "=&d" (tmp), "=Q" (*(int *) ptr)
+			: "d" (old << shift), "d" (new << shift),
+			  "d" (~(65535 << shift)), "Q" (*(int *) ptr)
+			: "memory", "cc");
+		return prev >> shift;
+	case 4:
+		asm volatile(
+			"	cs	%0,%3,%1\n"
+			: "=&d" (prev), "=Q" (*(int *) ptr)
+			: "0" (old), "d" (new), "Q" (*(int *) ptr)
+			: "memory", "cc");
+		return prev;
+#ifdef CONFIG_64BIT
+	case 8:
+		asm volatile(
+			"	csg	%0,%3,%1\n"
+			: "=&d" (prev), "=Q" (*(long *) ptr)
+			: "0" (old), "d" (new), "Q" (*(long *) ptr)
+			: "memory", "cc");
+		return prev;
+#endif /* CONFIG_64BIT */
+	}
+	__cmpxchg_called_with_bad_pointer();
+	return old;
+}
+
+#define cmpxchg(ptr, o, n)						\
+	((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(o),	\
+				       (unsigned long)(n), sizeof(*(ptr))))
+
+#include <asm-generic/cmpxchg-local.h>
+
+static inline unsigned long __cmpxchg_local(void *ptr,
+					    unsigned long old,
+					    unsigned long new, int size)
+{
+	switch (size) {
+	case 1:
+	case 2:
+	case 4:
+#ifdef CONFIG_64BIT
+	case 8:
+#endif
+		return __cmpxchg(ptr, old, new, size);
+	default:
+		return __cmpxchg_local_generic(ptr, old, new, size);
+	}
+
+	return old;
+}
+
+/*
+ * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
+ * them available.
+ */
+#define cmpxchg_local(ptr, o, n)					\
+	((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o),	\
+			(unsigned long)(n), sizeof(*(ptr))))
+#ifdef CONFIG_64BIT
+#define cmpxchg64_local(ptr, o, n)					\
+({									\
+	BUILD_BUG_ON(sizeof(*(ptr)) != 8);				\
+	cmpxchg_local((ptr), (o), (n));					\
+})
+#else
+#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
+#endif
+
+#endif /* __ASM_CMPXCHG_H */