28 lines
745 B
C
28 lines
745 B
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2020 ARM Ltd.
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*/
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#ifndef __ASM_VDSO_PROCESSOR_H
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#define __ASM_VDSO_PROCESSOR_H
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#ifndef __ASSEMBLY__
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#ifdef CONFIG_CPU_LOONGSON64
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/*
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* Loongson-3's SFB (Store-Fill-Buffer) may buffer writes indefinitely when a
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* tight read loop is executed, because reads take priority over writes & the
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* hardware (incorrectly) doesn't ensure that writes will eventually occur.
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*
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* Since spin loops of any kind should have a cpu_relax() in them, force an SFB
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* flush from cpu_relax() such that any pending writes will become visible as
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* expected.
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*/
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#define cpu_relax() smp_mb()
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#else
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#define cpu_relax() barrier()
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#endif
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#endif /* __ASSEMBLY__ */
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#endif /* __ASM_VDSO_PROCESSOR_H */
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