Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0-only */
2#ifndef __ASM_VDSO_PROCESSOR_H
3#define __ASM_VDSO_PROCESSOR_H
4
5#ifndef __ASSEMBLY__
6
7#include <asm/barrier.h>
8
9static inline void cpu_relax(void)
10{
11#ifdef __riscv_muldiv
12 int dummy;
13 /* In lieu of a halt instruction, induce a long-latency stall. */
14 __asm__ __volatile__ ("div %0, %0, zero" : "=r" (dummy));
15#endif
16
17#ifdef __riscv_zihintpause
18 /*
19 * Reduce instruction retirement.
20 * This assumes the PC changes.
21 */
22 __asm__ __volatile__ ("pause");
23#else
24 /* Encoding of the pause instruction */
25 __asm__ __volatile__ (".4byte 0x100000F");
26#endif
27 barrier();
28}
29
30#endif /* __ASSEMBLY__ */
31
32#endif /* __ASM_VDSO_PROCESSOR_H */