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 
9 static 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 /* __ASSEMBLY__ */
31 
32 #endif /* __ASM_VDSO_PROCESSOR_H */
33