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Create asm-generic/barrier.h

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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>
This commit is contained in:
David Howells 2012-03-28 18:30:03 +01:00
parent 34484277b1
commit 885df91ca3
2 changed files with 51 additions and 33 deletions
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50
include/asm-generic/barrier.h Normal file
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@ -0,0 +1,50 @@
/* 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 */

34
include/asm-generic/system.h
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@ -19,6 +19,7 @@
#include <linux/types.h>
#include <linux/irqflags.h>
#include <asm/barrier.h>
#include <asm/cmpxchg.h>
struct task_struct;
@ -33,42 +34,9 @@ extern struct task_struct *__switch_to(struct task_struct *,
#define arch_align_stack(x) (x)
#define nop() asm volatile ("nop")
#endif /* !__ASSEMBLY__ */
/*
* 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)
/*
* we make sure local_irq_enable() doesn't cause priority inversion
*/
#ifndef __ASSEMBLY__
/* This function doesn't exist, so you'll get a linker error
* if something tries to do an invalid xchg(). */