linux_dsm_epyc7002/include/asm-generic/barrier.h
Davidlohr Bueso 5a1b26d7c6 lcoking/barriers, arch: Use smp barriers in smp_store_release()
With commit b92b8b35a2 ("locking/arch: Rename set_mb() to smp_store_mb()")
it was made clear that the context of this call (and thus set_mb)
is strictly for CPU ordering, as opposed to IO. As such all archs
should use the smp variant of mb(), respecting the semantics and
saving a mandatory barrier on UP.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <linux-arch@vger.kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: dave@stgolabs.net
Link: http://lkml.kernel.org/r/1445975631-17047-3-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-01-12 20:46:46 +02:00

124 lines
2.4 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 dma_rmb
#define dma_rmb() rmb()
#endif
#ifndef dma_wmb
#define dma_wmb() wmb()
#endif
#ifndef read_barrier_depends
#define read_barrier_depends() do { } while (0)
#endif
#ifdef CONFIG_SMP
#ifndef smp_mb
#define smp_mb() mb()
#endif
#ifndef smp_rmb
#define smp_rmb() rmb()
#endif
#ifndef smp_wmb
#define smp_wmb() wmb()
#endif
#ifndef smp_read_barrier_depends
#define smp_read_barrier_depends() read_barrier_depends()
#endif
#else /* !CONFIG_SMP */
#ifndef smp_mb
#define smp_mb() barrier()
#endif
#ifndef smp_rmb
#define smp_rmb() barrier()
#endif
#ifndef smp_wmb
#define smp_wmb() barrier()
#endif
#ifndef smp_read_barrier_depends
#define smp_read_barrier_depends() do { } while (0)
#endif
#endif /* CONFIG_SMP */
#ifndef smp_store_mb
#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); smp_mb(); } while (0)
#endif
#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(); \
WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
___p1; \
})
#endif /* !__ASSEMBLY__ */
#endif /* __ASM_GENERIC_BARRIER_H */