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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)
#ifndef smp_mb__before_atomic
#define smp_mb__before_atomic() smp_mb()
#endif
#ifndef smp_mb__after_atomic
#define smp_mb__after_atomic() smp_mb()
#endif
#define smp_store_release(p, v) \
do { \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
ACCESS_ONCE(*p) = (v); \
} while (0)
#define smp_load_acquire(p) \
({ \
typeof(*p) ___p1 = ACCESS_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
___p1; \
})
#endif /* !__ASSEMBLY__ */
#endif /* __ASM_GENERIC_BARRIER_H */