[ltt-dev] [PATCH RFC] Native ARM7L support

[Paul E. McKenney]

The machine I am using is cortex-a9.  It may be necessary to create a
more intelligent mapping to the many variants of ARM.  Interestingly
enough, __sync_synchronize() -still- fails, so use an explicit asm
for the dmb instruction.

Leaving off the '-O' gives freaking slow results.  ;-)

Signed-off-by: Paul E. McKenney <paulmck at linux.vnet.ibm.com>
---

 configure.ac               |    4 +++
 urcu/arch_armv7l.h         |   59 +++++++++++++++++++++++++++++++++++++++++++++
 urcu/uatomic_arch_armv7l.h |   48 ++++++++++++++++++++++++++++++++++++
 3 files changed, 111 insertions(+)

diff --git a/configure.ac b/configure.ac
index 9274337..9e2615f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -51,6 +51,7 @@ case $host_cpu in
 	s390x) ARCHTYPE="s390" ;;
 	sparc64) ARCHTYPE="sparc64" ;;
 	alpha*) ARCHTYPE="alpha" ;;
+	armv7l) ARCHTYPE="armv7l" ;;
 	*) ARCHTYPE="unknown";;
 esac
 
@@ -61,6 +62,9 @@ if test "x$ARCHTYPE" != xx86 -a "x$ARCHTYPE" != xppc; then
 else
 	APISRC=tests/api_$ARCHTYPE.h
 fi
+if test "x$ARCHTYPE" == xarmv7l; then
+	CFLAGS="-mcpu=cortex-a9 -mtune=cortex-a9 -O2"
+fi
 
 AC_SUBST(ARCHTYPE)
 AC_SUBST(SUBARCHTYPE)
diff --git a/urcu/arch_armv7l.h b/urcu/arch_armv7l.h
new file mode 100644
index 0000000..5920a4d
--- /dev/null
+++ b/urcu/arch_armv7l.h
@@ -0,0 +1,59 @@
+#ifndef _URCU_ARCH_ARMV7L_H
+#define _URCU_ARCH_ARMV7L_H
+
+/*
+ * arch_unknown.h: trivial definitions for the "unknown" architecture.
+ *
+ * Copyright (c) 2010 Paul E. McKenney, IBM Corporation.
+ * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers at polymtl.ca>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <urcu/compiler.h>
+#include <urcu/config.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif 
+
+/* We don't know, so guess!!! */
+#define CACHE_LINE_SIZE	128
+
+#define mb()    asm volatile("dmb":::"memory")
+
+#include <stdlib.h>
+#include <sys/time.h>
+
+typedef unsigned long long cycles_t;
+
+static inline cycles_t get_cycles (void)
+{
+	cycles_t thetime;
+	struct timeval tv;
+
+	if (gettimeofday(&tv, NULL) != 0)
+		return 0;
+	thetime = ((cycles_t)tv.tv_sec) * 1000000ULL + ((cycles_t)tv.tv_usec);
+	return (cycles_t)thetime;
+}
+
+#ifdef __cplusplus 
+}
+#endif
+
+#include <urcu/arch_generic.h>
+
+#endif /* _URCU_ARCH_ARMV7L_H */
diff --git a/urcu/uatomic_arch_armv7l.h b/urcu/uatomic_arch_armv7l.h
new file mode 100644
index 0000000..5eece49
--- /dev/null
+++ b/urcu/uatomic_arch_armv7l.h
@@ -0,0 +1,48 @@
+#ifndef _URCU_ARCH_UATOMIC_ARMV7L_H
+#define _URCU_ARCH_UATOMIC_ARMV7L_H
+
+/* 
+ * Copyright (c) 1991-1994 by Xerox Corporation.  All rights reserved.
+ * Copyright (c) 1996-1999 by Silicon Graphics.  All rights reserved.
+ * Copyright (c) 1999-2004 Hewlett-Packard Development Company, L.P.
+ * Copyright (c) 2009      Mathieu Desnoyers
+ * Copyright (c) 2010      Paul E. McKenney, IBM Corporation
+ *			   (Adapted from uatomic_arch_unknown.h)
+ *
+ * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
+ * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
+ *
+ * Permission is hereby granted to use or copy this program
+ * for any purpose,  provided the above notices are retained on all copies.
+ * Permission to modify the code and to distribute modified code is granted,
+ * provided the above notices are retained, and a notice that the code was
+ * modified is included with the above copyright notice.
+ *
+ * Code inspired from libuatomic_ops-1.2, inherited in part from the
+ * Boehm-Demers-Weiser conservative garbage collector.
+ */
+
+#include <urcu/compiler.h>
+#include <urcu/system.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif 
+
+/* xchg */
+#define uatomic_xchg(addr, v)	 __sync_lock_test_and_set(addr, v);
+
+/* cmpxchg */
+#define uatomic_cmpxchg(addr, old, _new) \
+	__sync_val_compare_and_swap(addr, old, _new)
+
+/* uatomic_add_return */
+#define uatomic_add_return(addr, v)  __sync_add_and_fetch(addr, v)
+
+#ifdef __cplusplus 
+}
+#endif
+
+#include <urcu/uatomic_generic.h>
+
+#endif /* _URCU_ARCH_UATOMIC_ARMV7L_H */