X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=include%2Furcu%2Farch%2Farm.h;h=407f422a92ee7e0315785ff8b05fb6560864f7b9;hb=HEAD;hp=5d1c60836da9a34fb1f2f71783255f5532d546b3;hpb=3f0dd283a89ab114ffbf5c3dd46463217c6bb2ff;p=urcu.git

diff --git a/include/urcu/arch/arm.h b/include/urcu/arch/arm.h
index 5d1c608..407f422 100644
--- a/include/urcu/arch/arm.h
+++ b/include/urcu/arch/arm.h
@@ -1,25 +1,13 @@
+// SPDX-FileCopyrightText: 2010 Paul E. McKenney, IBM Corporation.
+// SPDX-FileCopyrightText: 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
 #ifndef _URCU_ARCH_ARM_H
 #define _URCU_ARCH_ARM_H
 
 /*
  * arch_arm.h: trivial definitions for the ARM architecture.
- *
- * Copyright (c) 2010 Paul E. McKenney, IBM Corporation.
- * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * 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>
@@ -30,7 +18,15 @@
 extern "C" {
 #endif
 
-#ifdef CONFIG_RCU_ARM_HAVE_DMB
+/*
+ * Using DMB is faster than the builtin __sync_synchronize and this instruction is
+ * part of the baseline ARMv7 ISA.
+ */
+#ifdef URCU_ARCH_ARMV7
+
+/* For backwards compat. */
+#define CONFIG_RCU_ARM_HAVE_DMB 1
+
 /*
  * Issues full system DMB operation.
  */
@@ -44,7 +40,8 @@ extern "C" {
 #define cmm_smp_mb()	__asm__ __volatile__ ("dmb ish":::"memory")
 #define cmm_smp_rmb()	__asm__ __volatile__ ("dmb ish":::"memory")
 #define cmm_smp_wmb()	__asm__ __volatile__ ("dmb ish":::"memory")
-#endif /* CONFIG_RCU_ARM_HAVE_DMB */
+
+#endif /* URCU_ARCH_ARMV7 */
 
 #include <stdlib.h>
 #include <sys/time.h>
@@ -70,6 +67,15 @@ extern "C" {
 # endif
 #endif
 
+/*
+ * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42263
+ */
+#ifdef URCU_GCC_VERSION
+# if URCU_GCC_VERSION >= 40400 && URCU_GCC_VERSION <= 40402
+#  error Your gcc version has a non-functional __sync_synchronize()
+# endif
+#endif
+
 #ifdef __cplusplus
 }
 #endif