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+/*
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+ * Copied from the kernel sources to tools/:
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+ *
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+ * Memory barrier definitions. This is based on information published
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+ * in the Processor Abstraction Layer and the System Abstraction Layer
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+ * manual.
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+ *
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+ * Copyright (C) 1998-2003 Hewlett-Packard Co
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+ * David Mosberger-Tang <davidm@hpl.hp.com>
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+ * Copyright (C) 1999 Asit Mallick <asit.k.mallick@intel.com>
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+ * Copyright (C) 1999 Don Dugger <don.dugger@intel.com>
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+ */
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+#ifndef _TOOLS_LINUX_ASM_IA64_BARRIER_H
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+#define _TOOLS_LINUX_ASM_IA64_BARRIER_H
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+
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+#include <linux/compiler.h>
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+
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+/*
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+ * Macros to force memory ordering. In these descriptions, "previous"
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+ * and "subsequent" refer to program order; "visible" means that all
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+ * architecturally visible effects of a memory access have occurred
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+ * (at a minimum, this means the memory has been read or written).
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+ *
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+ * wmb(): Guarantees that all preceding stores to memory-
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+ * like regions are visible before any subsequent
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+ * stores and that all following stores will be
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+ * visible only after all previous stores.
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+ * rmb(): Like wmb(), but for reads.
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+ * mb(): wmb()/rmb() combo, i.e., all previous memory
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+ * accesses are visible before all subsequent
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+ * accesses and vice versa. This is also known as
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+ * a "fence."
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+ *
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+ * Note: "mb()" and its variants cannot be used as a fence to order
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+ * accesses to memory mapped I/O registers. For that, mf.a needs to
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+ * be used. However, we don't want to always use mf.a because (a)
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+ * it's (presumably) much slower than mf and (b) mf.a is supported for
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+ * sequential memory pages only.
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+ */
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+
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+/* XXX From arch/ia64/include/uapi/asm/gcc_intrin.h */
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+#define ia64_mf() asm volatile ("mf" ::: "memory")
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+
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+#define mb() ia64_mf()
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+#define rmb() mb()
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+#define wmb() mb()
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+
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+#endif /* _TOOLS_LINUX_ASM_IA64_BARRIER_H */
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