[ltt-dev] [PATCH 1/5] Add S390 architecture specific headers

[Jan Blunck]

This implements atomic exchange and some other trivial operations like
barriers for the S390 architecture. All of this is based on the
"z/Architecture Principles of Operation" as released by IBM.

Note that api_s390.h is missing so urcutortures applications don't build.

Signed-off-by: Jan Blunck <jblunck at suse.de>
---
 arch_atomic_s390.h |   89 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 arch_s390.h        |   70 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 159 insertions(+), 0 deletions(-)
 create mode 100644 arch_atomic_s390.h
 create mode 100644 arch_s390.h

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 at 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 */
diff --git a/arch_s390.h b/arch_s390.h
new file mode 100644
index 0000000..72af7e3
--- /dev/null
+++ b/arch_s390.h
@@ -0,0 +1,70 @@
+#ifndef _ARCH_S390_H
+#define _ARCH_S390_H
+
+/*
+ * Trivial definitions for the S390 architecture.
+ *
+ * Copyright (C) 2009 Novell, Inc.
+ * Author: Jan Blunck <jblunck at suse.de>
+ *
+ * Based on the Principles of Operation "CPU Serialization" (5-91), "BRANCH ON
+ * CONDITION" (7-25) and "STORE CLOCK" (7-169).
+ *
+ * Inspired by arch_ppc.h which is:
+ * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers at polymtl.ca>
+ *
+ * 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.
+ */
+
+#include <compiler.h>
+#include <arch_atomic.h>
+
+#define CONFIG_HAVE_MEM_COHERENCY
+/* Assume SMP machine, given we don't have this information */
+#define CONFIG_SMP 1
+
+#ifndef BITS_PER_LONG
+#define BITS_PER_LONG	(__SIZEOF_LONG__ * 8)
+#endif
+
+#define mb()    __asm__ __volatile__("bcr 15,0" : : : "memory")
+#define rmb()   __asm__ __volatile__("bcr 15,0" : : : "memory");
+#define wmb()   __asm__ __volatile__("bcr 15,0" : : : "memory");
+#define mc()	barrier()
+#define rmc()	barrier()
+#define wmc()	barrier()
+
+#define smp_mb()	mb()
+#define smp_rmb()	rmb()
+#define smp_wmb()	wmb()
+#define smp_mc()	mc()
+#define smp_rmc()	rmc()
+#define smp_wmc()	wmc()
+
+/* Nop everywhere except on alpha. */
+#define smp_read_barrier_depends()
+
+static inline void cpu_relax(void)
+{
+	barrier();
+}
+
+static inline void sync_core()
+{
+	__asm__ __volatile__("bcr 15,0" : : : "memory");
+}
+
+typedef unsigned long long cycles_t;
+
+static inline cycles_t get_cycles (void)
+{
+	cycles_t cycles;
+
+	__asm__ __volatile__("stck %0" : "=m" (cycles) : : "cc", "memory" );
+
+	return cycles;
+}
+
+#endif /* _ARCH_S390_H */
-- 
1.6.1.3