[ltt-dev] [PATCH 3/4] Add native ARM port for armv7l

[paulmck@linux.vnet.ibm.com (Paul E. McKenney)]

Add native support for armv7l.  Other variants of ARM will likely require
separate ports.  The gcc __sync_ approach works back to at least 2.6.15
kernels.

As suggested by Paolo Bonzini, defer the definition of CACHE_LINE_SIZE
to arch_generic.h.

Signed-off-by: Paul E. McKenney <paulmck at linux.vnet.ibm.com>
---
 configure.ac               |    4 +++
 urcu/arch_armv7l.h         |   56 ++++++++++++++++++++++++++++++++++++++++++++
 urcu/uatomic_arch_armv7l.h |   50 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 110 insertions(+), 0 deletions(-)
 create mode 100644 urcu/arch_armv7l.h
 create mode 100644 urcu/uatomic_arch_armv7l.h

diff --git a/configure.ac b/configure.ac
index 61a0d76..7b46004 100644
--- a/configure.ac
+++ b/configure.ac
@@ -52,6 +52,7 @@ case $host_cpu in
 	sparc64) ARCHTYPE="sparc64" ;;
 	alpha*) ARCHTYPE="alpha" ;;
 	ia64) ARCHTYPE="gcc" ;;
+	armv7l) ARCHTYPE="armv7l" ;;
 	*) ARCHTYPE="unknown";;
 esac
 
@@ -67,6 +68,9 @@ if test "x$ARCHTYPE" != xx86 -a "x$ARCHTYPE" != xppc; then
 else
 	APISRC=tests/api_$ARCHTYPE.h
 fi
+if test "$ARCHTYPE" == "armv7l"; then
+	CFLAGS="-mcpu=cortex-a9 -mtune=cortex-a9 -O"
+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..b4049cd
--- /dev/null
+++ b/urcu/arch_armv7l.h
@@ -0,0 +1,56 @@
+#ifndef _URCU_ARCH_ARMV7L_H
+#define _URCU_ARCH_ARMV7L_H
+
+/*
+ * arch_armv7l.h: trivial definitions for the ARMv7 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 
+
+#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..b68c818
--- /dev/null
+++ b/urcu/uatomic_arch_armv7l.h
@@ -0,0 +1,50 @@
+#ifndef _URCU_ARCH_UATOMIC_ARMV7L_H
+#define _URCU_ARCH_UATOMIC_ARMV7L_H
+
+/* 
+ * Atomics for ARMv7.  This approach is usable on kernels back to 2.6.15.
+ *
+ * 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_ppc.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 */
-- 
1.7.0.6