[LIBGOMP] Add ARM optimized futex support.

diff --git a/libgomp/config/linux/arm/futex.h b/libgomp/config/linux/arm/futex.h
new file mode 100644
index 0000000..7324b78
--- /dev/null
+++ b/libgomp/config/linux/arm/futex.h
@@ -0,0 +1,75 @@ 
+/* Copyright (C) 2010 Free Software Foundation, Inc.
+   Contributed by ARM Ltd.
+
+   This file is part of the GNU OpenMP Library (libgomp).
+
+   Libgomp is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   Libgomp 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 General Public License for
+   more details.
+
+   Under Section 7 of GPL version 3, you are granted additional
+   permissions described in the GCC Runtime Library Exception, version
+   3.1, as published by the Free Software Foundation.
+
+   You should have received a copy of the GNU General Public License and
+   a copy of the GCC Runtime Library Exception along with this program;
+   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* Provide target-specific access to the futex system call.  */
+
+/* The include file hierachy above us (wait.h) has pushed visibility
+   hidden, this will be applied to prototypes with headers we include
+   with the effect that we cannot link against an external function
+   (syscall). The solution here is to push default visibility, include
+   our required headers then reinstante the original visibility.  */
+
+#pragma GCC visibility push(default)
+
+#define _GNU_SOURCE 
+#include <unistd.h>
+#include <sys/syscall.h>
+
+#pragma GCC visibility pop
+
+static inline void
+futex_wait (int *addr, int val)
+{
+  long err = syscall (SYS_futex, addr, gomp_futex_wait, val);
+  if (__builtin_expect (err == -ENOSYS, 0))
+    {
+      gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG;
+      gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG;
+      syscall (SYS_futex, addr, gomp_futex_wait, val);
+    }
+}
+
+static inline void
+futex_wake (int *addr, int count)
+{
+  long err = syscall (SYS_futex, addr, gomp_futex_wake, count);
+  if (__builtin_expect (err == -ENOSYS, 0))
+    {
+      gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG;
+      gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG;
+      syscall (SYS_futex, addr, gomp_futex_wake, count);
+    }
+}
+
+static inline void
+cpu_relax (void)
+{
+  __asm volatile ("" : : : "memory");
+}
+
+static inline void
+atomic_write_barrier (void)
+{
+  __sync_synchronize ();
+}
diff --git a/libgomp/config/linux/arm/mutex.h b/libgomp/config/linux/arm/mutex.h
new file mode 100644
index 0000000..30021d5
--- /dev/null
+++ b/libgomp/config/linux/arm/mutex.h
@@ -0,0 +1,28 @@ 
+/* Copyright (C) 2010 Free Software Foundation, Inc.
+   Contributed by ARM Ltd.
+
+   This file is part of the GNU OpenMP Library (libgomp).
+
+   Libgomp is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   Libgomp 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 General Public License for
+   more details.
+
+   Under Section 7 of GPL version 3, you are granted additional
+   permissions described in the GCC Runtime Library Exception, version
+   3.1, as published by the Free Software Foundation.
+
+   You should have received a copy of the GNU General Public License and
+   a copy of the GCC Runtime Library Exception along with this program;
+   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* ARM needs the same correct usage of __sync_synchronize and
+   __sync_lock_test_and_set as ia64.  So we just use its mutex.h.  */
+
+#include "config/linux/ia64/mutex.h"
diff --git a/libgomp/configure.tgt b/libgomp/configure.tgt
index 16bb888..6ab9e4d 100644
--- a/libgomp/configure.tgt
+++ b/libgomp/configure.tgt
@@ -31,6 +31,10 @@  if test $enable_linux_futex = yes; then
 	config_path="linux/alpha linux posix"
 	;;
 
+    arm*-*-linux*)
+	config_path="linux/arm linux posix"
+	;;
+
     ia64*-*-linux*)
 	config_path="linux/ia64 linux posix"
 	;;