X-Git-Url: http://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=arch_atomic_s390.h;fp=arch_atomic_s390.h;h=cb85e6a0ae80b83698f2a23ba1630ff53ca3425a;hp=0000000000000000000000000000000000000000;hb=ac26f1a80b59a596a904a8d3a271460c8eb4334d;hpb=d38b03b804320e984fbf1c816f808a0e7e70cfa5

diff --git a/arch_atomic_s390.h b/arch_atomic_s390.h
new file mode 100644
index 0000000..cb85e6a
--- /dev/null
+++ b/arch_atomic_s390.h
@@ -0,0 +1,89 @@
+#ifndef _ARCH_ATOMIC_S390_H
+#define _ARCH_ATOMIC_S390_H
+
+/*
+ * Atomic exchange operations for the S390 architecture.
+ *
+ * Copyright (C) 2009 Novell, Inc.
+ * Author: Jan Blunck <jblunck@suse.de>
+ *
+ * This is taken from the Principles of Operation Appendix A "Conditional
+ * Swapping Instructions (CS, CDS)".
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 2.1 as
+ * published by the Free  Software Foundation.
+ */
+
+#ifndef __SIZEOF_LONG__
+#ifdef __s390x__
+#define __SIZEOF_LONG__ 8
+#else
+#define __SIZEOF_LONG__ 4
+#endif
+#endif
+
+#ifndef BITS_PER_LONG
+#define BITS_PER_LONG	(__SIZEOF_LONG__ * 8)
+#endif
+
+#ifndef _INCLUDE_API_H
+
+static __attribute__((always_inline))
+unsigned int atomic_exchange_32(volatile unsigned int *addr, unsigned int val)
+{
+	unsigned int result;
+
+	__asm__ __volatile__(
+		"0:	cs %0,%2,%1\n"
+		"	brc 4,0b\n"
+		: "=&r"(result), "=m" (*addr)
+		: "r"(val), "m" (*addr)
+		: "memory", "cc");
+
+	return result;
+}
+
+#if (BITS_PER_LONG == 64)
+
+static __attribute__((always_inline))
+unsigned long atomic_exchange_64(volatile unsigned long *addr,
+				 unsigned long val)
+{
+	unsigned long result;
+
+	__asm__ __volatile__(
+		"0:	csg %0,%2,%1\n"
+		"	brc 4,0b\n"
+		: "=&r"(result), "=m" (*addr)
+		: "r"(val), "m" (*addr)
+		: "memory", "cc");
+
+	return result;
+}
+
+#endif
+
+static __attribute__((always_inline))
+unsigned long _atomic_exchange(volatile void *addr, unsigned long val, int len)
+{
+	switch (len) {
+	case 4:
+		return atomic_exchange_32(addr, val);
+#if (BITS_PER_LONG == 64)
+	case 8:
+		return atomic_exchange_64(addr, val);
+#endif
+	default:
+		__asm__ __volatile__(".long	0xd00d00");
+	}
+
+	return 0;
+}
+
+#define xchg(addr, v)	(__typeof__(*(addr))) _atomic_exchange((addr), (v), \
+							       sizeof(*(addr)))
+
+#endif /* #ifndef _INCLUDE_API_H */
+
+#endif /* ARCH_ATOMIC_S390_H */