linux-next/include/asm-generic/barrier.h
Peter Zijlstra 93ea02bb84 arch: Clean up asm/barrier.h implementations using asm-generic/barrier.h
We're going to be adding a few new barrier primitives, and in order to
avoid endless duplication make more agressive use of
asm-generic/barrier.h.

Change the asm-generic/barrier.h such that it allows partial barrier
definitions and fills out the rest with defaults.

There are a few architectures (m32r, m68k) that could probably
do away with their barrier.h file entirely but are kept for now due to
their unconventional nop() implementation.

Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Victor Kaplansky <VICTORK@il.ibm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20131213150640.846368594@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-01-12 10:37:15 +01:00

67 lines
1.5 KiB
C

/*
* Generic barrier definitions, originally 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__
#include <linux/compiler.h>
#ifndef nop
#define nop() asm volatile ("nop")
#endif
/*
* Force strict CPU ordering. And yes, this is required on UP too when we're
* talking to devices.
*
* Fall back to compiler barriers if nothing better is provided.
*/
#ifndef mb
#define mb() barrier()
#endif
#ifndef rmb
#define rmb() mb()
#endif
#ifndef wmb
#define wmb() mb()
#endif
#ifndef read_barrier_depends
#define read_barrier_depends() do { } while (0)
#endif
#ifdef CONFIG_SMP
#define smp_mb() mb()
#define smp_rmb() rmb()
#define smp_wmb() wmb()
#define smp_read_barrier_depends() read_barrier_depends()
#else
#define smp_mb() barrier()
#define smp_rmb() barrier()
#define smp_wmb() barrier()
#define smp_read_barrier_depends() do { } while (0)
#endif
#ifndef set_mb
#define set_mb(var, value) do { (var) = (value); mb(); } while (0)
#endif
#endif /* !__ASSEMBLY__ */
#endif /* __ASM_GENERIC_BARRIER_H */