processor.h

 1/* SPDX-License-Identifier: GPL-2.0-only */
 2#ifndef __ASM_VDSO_PROCESSOR_H
 3#define __ASM_VDSO_PROCESSOR_H
 4
 5#ifndef __ASSEMBLER__
 6
 7#include <asm-generic/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 CONFIG_TOOLCHAIN_HAS_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 /* __ASSEMBLER__ */
31
32#endif /* __ASM_VDSO_PROCESSOR_H */