/* SPDX-License-Identifier: GPL-2.0-only */ #ifndef __ASM_VDSO_PROCESSOR_H #define __ASM_VDSO_PROCESSOR_H #ifndef __ASSEMBLY__ #include <linux/jump_label.h> #include <asm/barrier.h> #include <asm/hwcap.h> static inline void cpu_relax(void) { if (!static_branch_likely(&riscv_isa_ext_keys[RISCV_ISA_EXT_KEY_ZIHINTPAUSE])) { #ifdef __riscv_muldiv int dummy; /* In lieu of a halt instruction, induce a long-latency stall. */ __asm__ __volatile__ ("div %0, %0, zero" : "=r" (dummy)); #endif } else { /* * Reduce instruction retirement. * This assumes the PC changes. */ #ifdef __riscv_zihintpause __asm__ __volatile__ ("pause"); #else /* Encoding of the pause instruction */ __asm__ __volatile__ (".4byte 0x100000F"); #endif } barrier(); } #endif /* __ASSEMBLY__ */ #endif /* __ASM_VDSO_PROCESSOR_H */