| /* SPDX-License-Identifier: GPL-2.0-only */ |
| /* |
| * Copyright (C) 2014-15 Synopsys, Inc. (www.synopsys.com) |
| */ |
| |
| #ifndef __ASM_BARRIER_H |
| #define __ASM_BARRIER_H |
| |
| #ifdef CONFIG_ISA_ARCV2 |
| |
| /* |
| * ARCv2 based HS38 cores are in-order issue, but still weakly ordered |
| * due to micro-arch buffering/queuing of load/store, cache hit vs. miss ... |
| * |
| * Explicit barrier provided by DMB instruction |
| * - Operand supports fine grained load/store/load+store semantics |
| * - Ensures that selected memory operation issued before it will complete |
| * before any subsequent memory operation of same type |
| * - DMB guarantees SMP as well as local barrier semantics |
| * (asm-generic/barrier.h ensures sane smp_*mb if not defined here, i.e. |
| * UP: barrier(), SMP: smp_*mb == *mb) |
| * - DSYNC provides DMB+completion_of_cache_bpu_maintenance_ops hence not needed |
| * in the general case. Plus it only provides full barrier. |
| */ |
| |
| #define mb() asm volatile("dmb 3\n" : : : "memory") |
| #define rmb() asm volatile("dmb 1\n" : : : "memory") |
| #define wmb() asm volatile("dmb 2\n" : : : "memory") |
| |
| #else |
| |
| /* |
| * ARCompact based cores (ARC700) only have SYNC instruction which is super |
| * heavy weight as it flushes the pipeline as well. |
| * There are no real SMP implementations of such cores. |
| */ |
| |
| #define mb() asm volatile("sync\n" : : : "memory") |
| |
| #endif |
| |
| #include <asm-generic/barrier.h> |
| |
| #endif |
