Add S390 architecture specific headers

[urcu.git] / arch_atomic_s390.h

diff --git a/arch_atomic_s390.h b/arch_atomic_s390.h
new file mode 100644 (file)
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 */