Borrow the cpu_relax() definitions from kernel's arch/riscv/include/asm/vdso/processor.h to tools/ for riscv.
Signed-off-by: Haibo Xu haibo1.xu@intel.com Reviewed-by: Andrew Jones ajones@ventanamicro.com --- tools/arch/riscv/include/asm/vdso/processor.h | 32 +++++++++++++++++++ 1 file changed, 32 insertions(+) create mode 100644 tools/arch/riscv/include/asm/vdso/processor.h
diff --git a/tools/arch/riscv/include/asm/vdso/processor.h b/tools/arch/riscv/include/asm/vdso/processor.h new file mode 100644 index 000000000000..662aca039848 --- /dev/null +++ b/tools/arch/riscv/include/asm/vdso/processor.h @@ -0,0 +1,32 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef __ASM_VDSO_PROCESSOR_H +#define __ASM_VDSO_PROCESSOR_H + +#ifndef __ASSEMBLY__ + +#include <asm-generic/barrier.h> + +static inline void cpu_relax(void) +{ +#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 + +#ifdef CONFIG_TOOLCHAIN_HAS_ZIHINTPAUSE + /* + * Reduce instruction retirement. + * This assumes the PC changes. + */ + __asm__ __volatile__ ("pause"); +#else + /* Encoding of the pause instruction */ + __asm__ __volatile__ (".4byte 0x100000F"); +#endif + barrier(); +} + +#endif /* __ASSEMBLY__ */ + +#endif /* __ASM_VDSO_PROCESSOR_H */