1/* 2 * Copyright (C) 2014-15 Synopsys, Inc. (www.synopsys.com) 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 */ 8 9#ifndef __ASM_BARRIER_H 10#define __ASM_BARRIER_H 11 12#ifdef CONFIG_ISA_ARCV2 13 14/* 15 * ARCv2 based HS38 cores are in-order issue, but still weakly ordered 16 * due to micro-arch buffering/queuing of load/store, cache hit vs. miss ... 17 * 18 * Explicit barrier provided by DMB instruction 19 * - Operand supports fine grained load/store/load+store semantics 20 * - Ensures that selected memory operation issued before it will complete 21 * before any subsequent memory operation of same type 22 * - DMB guarantees SMP as well as local barrier semantics 23 * (asm-generic/barrier.h ensures sane smp_*mb if not defined here, i.e. 24 * UP: barrier(), SMP: smp_*mb == *mb) 25 * - DSYNC provides DMB+completion_of_cache_bpu_maintenance_ops hence not needed 26 * in the general case. Plus it only provides full barrier. 27 */ 28 29#define mb() asm volatile("dmb 3\n" : : : "memory") 30#define rmb() asm volatile("dmb 1\n" : : : "memory") 31#define wmb() asm volatile("dmb 2\n" : : : "memory") 32 33#endif 34 35#ifdef CONFIG_ISA_ARCOMPACT 36 37/* 38 * ARCompact based cores (ARC700) only have SYNC instruction which is super 39 * heavy weight as it flushes the pipeline as well. 40 * There are no real SMP implementations of such cores. 41 */ 42 43#define mb() asm volatile("sync\n" : : : "memory") 44#endif 45 46#include <asm-generic/barrier.h> 47 48#endif 49