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885df91ca3
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>
50 lines
1.4 KiB
C
50 lines
1.4 KiB
C
/* Generic barrier definitions, based on MN10300 definitions.
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*
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* It should be possible to use these on really simple architectures,
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* but it serves more as a starting point for new ports.
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*
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*/
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#ifndef __ASM_GENERIC_BARRIER_H
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#define __ASM_GENERIC_BARRIER_H
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#ifndef __ASSEMBLY__
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#define nop() asm volatile ("nop")
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/*
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* Force strict CPU ordering.
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* And yes, this is required on UP too when we're talking
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* to devices.
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*
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* This implementation only contains a compiler barrier.
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*/
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#define mb() asm volatile ("": : :"memory")
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#define rmb() mb()
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#define wmb() asm volatile ("": : :"memory")
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#ifdef CONFIG_SMP
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#define smp_mb() mb()
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#define smp_rmb() rmb()
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#define smp_wmb() wmb()
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#else
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#define smp_mb() barrier()
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#define smp_rmb() barrier()
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#define smp_wmb() barrier()
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#endif
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#define set_mb(var, value) do { var = value; mb(); } while (0)
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#define set_wmb(var, value) do { var = value; wmb(); } while (0)
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#define read_barrier_depends() do {} while (0)
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#define smp_read_barrier_depends() do {} while (0)
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#endif /* !__ASSEMBLY__ */
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#endif /* __ASM_GENERIC_BARRIER_H */
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