47 lines
1.5 KiB
C
47 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copied from the kernel sources:
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*
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* Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
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*/
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#ifndef _TOOLS_LINUX_ASM_POWERPC_BARRIER_H
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#define _TOOLS_LINUX_ASM_POWERPC_BARRIER_H
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/*
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* Memory barrier.
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* The sync instruction guarantees that all memory accesses initiated
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* by this processor have been performed (with respect to all other
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* mechanisms that access memory). The eieio instruction is a barrier
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* providing an ordering (separately) for (a) cacheable stores and (b)
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* loads and stores to non-cacheable memory (e.g. I/O devices).
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*
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* mb() prevents loads and stores being reordered across this point.
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* rmb() prevents loads being reordered across this point.
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* wmb() prevents stores being reordered across this point.
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*
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* *mb() variants without smp_ prefix must order all types of memory
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* operations with one another. sync is the only instruction sufficient
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* to do this.
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*/
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#define mb() __asm__ __volatile__ ("sync" : : : "memory")
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#define rmb() __asm__ __volatile__ ("sync" : : : "memory")
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#define wmb() __asm__ __volatile__ ("sync" : : : "memory")
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#if defined(__powerpc64__)
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#define smp_lwsync() __asm__ __volatile__ ("lwsync" : : : "memory")
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#define smp_store_release(p, v) \
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do { \
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smp_lwsync(); \
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WRITE_ONCE(*p, v); \
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} while (0)
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#define smp_load_acquire(p) \
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({ \
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typeof(*p) ___p1 = READ_ONCE(*p); \
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smp_lwsync(); \
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___p1; \
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})
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#endif /* defined(__powerpc64__) */
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#endif /* _TOOLS_LINUX_ASM_POWERPC_BARRIER_H */
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