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/*
* Based on arch/arm/include/asm/barrier.h
*
* Copyright (C) 2012 ARM Ltd.
* Copyright (C) 2013 Regents of the University of California
* Copyright (C) 2017 SiFive
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _ASM_RISCV_BARRIER_H
#define _ASM_RISCV_BARRIER_H
#ifndef __ASSEMBLY__
#define nop() __asm__ __volatile__ ("nop")
#define RISCV_FENCE(p, s) \
__asm__ __volatile__ ("fence " #p "," #s : : : "memory")
/* These barriers need to enforce ordering on both devices or memory. */
#define mb() RISCV_FENCE(iorw,iorw)
#define rmb() RISCV_FENCE(ir,ir)
#define wmb() RISCV_FENCE(ow,ow)
/* These barriers do not need to enforce ordering on devices, just memory. */
#define smp_mb() RISCV_FENCE(rw,rw)
#define smp_rmb() RISCV_FENCE(r,r)
#define smp_wmb() RISCV_FENCE(w,w)
/*
* These fences exist to enforce ordering around the relaxed AMOs. The
* documentation defines that
* "
* atomic_fetch_add();
* is equivalent to:
* smp_mb__before_atomic();
* atomic_fetch_add_relaxed();
* smp_mb__after_atomic();
* "
* So we emit full fences on both sides.
*/
#define __smb_mb__before_atomic() smp_mb()
#define __smb_mb__after_atomic() smp_mb()
/*
* These barriers prevent accesses performed outside a spinlock from being moved
* inside a spinlock. Since RISC-V sets the aq/rl bits on our spinlock only
* enforce release consistency, we need full fences here.
*/
#define smb_mb__before_spinlock() smp_mb()
#define smb_mb__after_spinlock() smp_mb()
#include <asm-generic/barrier.h>
#endif /* __ASSEMBLY__ */
#endif /* _ASM_RISCV_BARRIER_H */
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