1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0-only */ 2*4882a593Smuzhiyun /* 3*4882a593Smuzhiyun * Copyright (C) 2020 ARM Ltd. 4*4882a593Smuzhiyun */ 5*4882a593Smuzhiyun #ifndef __ASM_VDSO_PROCESSOR_H 6*4882a593Smuzhiyun #define __ASM_VDSO_PROCESSOR_H 7*4882a593Smuzhiyun 8*4882a593Smuzhiyun #ifndef __ASSEMBLY__ 9*4882a593Smuzhiyun 10*4882a593Smuzhiyun #ifdef CONFIG_CPU_LOONGSON64 11*4882a593Smuzhiyun /* 12*4882a593Smuzhiyun * Loongson-3's SFB (Store-Fill-Buffer) may buffer writes indefinitely when a 13*4882a593Smuzhiyun * tight read loop is executed, because reads take priority over writes & the 14*4882a593Smuzhiyun * hardware (incorrectly) doesn't ensure that writes will eventually occur. 15*4882a593Smuzhiyun * 16*4882a593Smuzhiyun * Since spin loops of any kind should have a cpu_relax() in them, force an SFB 17*4882a593Smuzhiyun * flush from cpu_relax() such that any pending writes will become visible as 18*4882a593Smuzhiyun * expected. 19*4882a593Smuzhiyun */ 20*4882a593Smuzhiyun #define cpu_relax() smp_mb() 21*4882a593Smuzhiyun #else 22*4882a593Smuzhiyun #define cpu_relax() barrier() 23*4882a593Smuzhiyun #endif 24*4882a593Smuzhiyun 25*4882a593Smuzhiyun #endif /* __ASSEMBLY__ */ 26*4882a593Smuzhiyun 27*4882a593Smuzhiyun #endif /* __ASM_VDSO_PROCESSOR_H */ 28