Re: [PATCH 1/3] MIPS: kernel: Support extracting off-line stack traces from user-space with perf

[Thomas Bogendoerfer <tsbogend@alpha.franken.de>]

On Tue, Dec 29, 2020 at 08:55:59PM +0800, Tiezhu Yang wrote:
> +++ b/arch/mips/include/uapi/asm/perf_regs.h
> @@ -0,0 +1,42 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +#ifndef _ASM_MIPS_PERF_REGS_H
> +#define _ASM_MIPS_PERF_REGS_H
> +
> +enum perf_event_mips_regs {
> +	PERF_REG_MIPS_PC,
> +	PERF_REG_MIPS_R1,
> +	PERF_REG_MIPS_R2,
> +	PERF_REG_MIPS_R3,
> +	PERF_REG_MIPS_R4,
> +	PERF_REG_MIPS_R5,
> +	PERF_REG_MIPS_R6,
> +	PERF_REG_MIPS_R7,
> +	PERF_REG_MIPS_R8,
> +	PERF_REG_MIPS_R9,
> +	PERF_REG_MIPS_R10,
> +	PERF_REG_MIPS_R11,
> +	PERF_REG_MIPS_R12,
> +	PERF_REG_MIPS_R13,
> +	PERF_REG_MIPS_R14,
> +	PERF_REG_MIPS_R15,
> +	PERF_REG_MIPS_R16,
> +	PERF_REG_MIPS_R17,
> +	PERF_REG_MIPS_R18,
> +	PERF_REG_MIPS_R19,
> +	PERF_REG_MIPS_R20,
> +	PERF_REG_MIPS_R21,
> +	PERF_REG_MIPS_R22,
> +	PERF_REG_MIPS_R23,
> +	PERF_REG_MIPS_R24,
> +	PERF_REG_MIPS_R25,
> +	/*
> +	 * 26 and 27 are k0 and k1, they are always clobbered thus not
> +	 * stored.
> +	 */

haveing this hole here make all code more complicated. Does it hurt
to have R26 and R27 in the list ?

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]