nuttx/arch/risc-v/include/barriers.h

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 * arch/risc-v/include/barriers.h
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
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 *   http://www.apache.org/licenses/LICENSE-2.0
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 * Unless required by applicable law or agreed to in writing, software
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#ifndef __ARCH_RISCV_INCLUDE_BARRIERS_H
#define __ARCH_RISCV_INCLUDE_BARRIERS_H

/* Common memory barriers (p=predecessor, s=successor) */

#define __FENCE(p, s) __asm__ __volatile__ ("fence "#p", "#s  ::: "memory")

/* __DMB() is used to flush local data caches (memory) */

#define __DMB()       __FENCE(rw, rw)

/* __MB() is a full memory barrier */

#define __MB()        __FENCE(iorw, iorw)

/* __ISB() is used to synchronize the instruction and data streams */

#define __ISB()       __asm__ __volatile__ ("fence.i" ::: "memory")

#endif /* __ARCH_RISCV_INCLUDE_BARRIERS_H */