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tools: riscv: Add header file vdso/processor.h
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> Signed-off-by: Anup Patel <anup@brainfault.org>
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tools/arch/riscv/include/asm/vdso/processor.h
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tools/arch/riscv/include/asm/vdso/processor.h
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/* SPDX-License-Identifier: GPL-2.0-only */
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#ifndef __ASM_VDSO_PROCESSOR_H
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#define __ASM_VDSO_PROCESSOR_H
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#ifndef __ASSEMBLY__
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#include <asm-generic/barrier.h>
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static inline void cpu_relax(void)
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{
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#ifdef __riscv_muldiv
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int dummy;
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/* In lieu of a halt instruction, induce a long-latency stall. */
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__asm__ __volatile__ ("div %0, %0, zero" : "=r" (dummy));
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#endif
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#ifdef CONFIG_TOOLCHAIN_HAS_ZIHINTPAUSE
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/*
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* Reduce instruction retirement.
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* This assumes the PC changes.
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*/
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__asm__ __volatile__ ("pause");
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#else
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/* Encoding of the pause instruction */
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__asm__ __volatile__ (".4byte 0x100000F");
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#endif
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barrier();
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}
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#endif /* __ASSEMBLY__ */
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#endif /* __ASM_VDSO_PROCESSOR_H */
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