linux_kernel/arch/s390/include/asm/barrier.h

/*
 * Copyright IBM Corp. 1999, 2009
 *
 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
 */

#ifndef __ASM_BARRIER_H
#define __ASM_BARRIER_H

/*
 * Force strict CPU ordering.
 * And yes, this is required on UP too when we're talking
 * to devices.
 */

#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
/* Fast-BCR without checkpoint synchronization */
#define __ASM_BARRIER "bcr 14,0\n"
#else
#define __ASM_BARRIER "bcr 15,0\n"
#endif

#define mb() do {  asm volatile(__ASM_BARRIER : : : "memory"); } while (0)

#define rmb()				mb()
#define wmb()				mb()
#define dma_rmb()			rmb()
#define dma_wmb()			wmb()
#define smp_mb()			mb()
#define smp_rmb()			rmb()
#define smp_wmb()			wmb()

#define read_barrier_depends()		do { } while (0)
#define smp_read_barrier_depends()	do { } while (0)

#define smp_mb__before_atomic()		smp_mb()
#define smp_mb__after_atomic()		smp_mb()

#define set_mb(var, value)		do { var = value; mb(); } while (0)

#define smp_store_release(p, v)						\
do {									\
	compiletime_assert_atomic_type(*p);				\
	barrier();							\
	ACCESS_ONCE(*p) = (v);						\
} while (0)

#define smp_load_acquire(p)						\
({									\
	typeof(*p) ___p1 = ACCESS_ONCE(*p);				\
	compiletime_assert_atomic_type(*p);				\
	barrier();							\
	___p1;								\
})

#endif /* __ASM_BARRIER_H */