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authorDavid Howells <dhowells@redhat.com>2012-03-28 18:30:03 +0100
committerDavid Howells <dhowells@redhat.com>2012-03-28 18:30:03 +0100
commit885df91ca3571afd4b3f50f3391329bbf3c9e262 (patch)
treee66773beb0fb84fc4a43037ba829719b3cbabe47 /include/asm-generic/barrier.h
parent34484277b173d0af1bb00532a264940b57920429 (diff)
Create asm-generic/barrier.h
Create asm-generic/barrier.h and move the barrier definitions from asm-generic/system.h to it. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'include/asm-generic/barrier.h')
-rw-r--r--include/asm-generic/barrier.h50
1 files changed, 50 insertions, 0 deletions
diff --git a/include/asm-generic/barrier.h b/include/asm-generic/barrier.h
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+/* Generic barrier definitions, based on MN10300 definitions.
+ *
+ * It should be possible to use these on really simple architectures,
+ * but it serves more as a starting point for new ports.
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+#ifndef __ASM_GENERIC_BARRIER_H
+#define __ASM_GENERIC_BARRIER_H
+
+#ifndef __ASSEMBLY__
+
+#define nop() asm volatile ("nop")
+
+/*
+ * Force strict CPU ordering.
+ * And yes, this is required on UP too when we're talking
+ * to devices.
+ *
+ * This implementation only contains a compiler barrier.
+ */
+
+#define mb() asm volatile ("": : :"memory")
+#define rmb() mb()
+#define wmb() asm volatile ("": : :"memory")
+
+#ifdef CONFIG_SMP
+#define smp_mb() mb()
+#define smp_rmb() rmb()
+#define smp_wmb() wmb()
+#else
+#define smp_mb() barrier()
+#define smp_rmb() barrier()
+#define smp_wmb() barrier()
+#endif
+
+#define set_mb(var, value) do { var = value; mb(); } while (0)
+#define set_wmb(var, value) do { var = value; wmb(); } while (0)
+
+#define read_barrier_depends() do {} while (0)
+#define smp_read_barrier_depends() do {} while (0)
+
+#endif /* !__ASSEMBLY__ */
+#endif /* __ASM_GENERIC_BARRIER_H */