| /* |
| * Copyright (C) 2016, Emilio G. Cota <cota@braap.org> |
| * |
| * License: GNU GPL, version 2. |
| * See the COPYING file in the top-level directory. |
| */ |
| #ifndef QEMU_PROCESSOR_H |
| #define QEMU_PROCESSOR_H |
| |
| #include "qemu/atomic.h" |
| |
| #if defined(__i386__) || defined(__x86_64__) |
| # define cpu_relax() asm volatile("rep; nop" ::: "memory") |
| |
| #elif defined(__ia64__) |
| # define cpu_relax() asm volatile("hint @pause" ::: "memory") |
| |
| #elif defined(__aarch64__) |
| # define cpu_relax() asm volatile("yield" ::: "memory") |
| |
| #elif defined(__powerpc64__) |
| /* set Hardware Multi-Threading (HMT) priority to low; then back to medium */ |
| # define cpu_relax() asm volatile("or 1, 1, 1;" \ |
| "or 2, 2, 2;" ::: "memory") |
| |
| #else |
| # define cpu_relax() barrier() |
| #endif |
| |
| #endif /* QEMU_PROCESSOR_H */ |
