linux-kernel - Re: [PATCH] perf tools: add aarch64 registers to --user-regs

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Date:   Tue, 1 Dec 2020 11:46:27 +0800
From:   Leo Yan <leo.yan@...aro.org>
To:     Alexandre Truong <alexandre.truong@....com>
Cc:     linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
        james.clark@....com, John Garry <john.garry@...wei.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Will Deacon <will.deacon@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Mathieu Poirier <mathieu.poirier@...aro.org>
Subject: Re: [PATCH] perf tools: add aarch64 registers to --user-regs

On Fri, Nov 27, 2020 at 03:39:23PM +0000, Alexandre Truong wrote:
> Previously, this command returns no help message on aarch64:
> 
>   -> ./perf record --user-regs=?
> 
>   available registers:
>   Usage: perf record [<options>] [<command>]
>       or: perf record [<options>] -- <command> [<options>]
> 
> With this change, the registers are listed.
> 
>   -> ./perf record --user-regs=?
> 
>   available registers: x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 x10 x11 x12 x13 x14 x15 x16 x17 x18 x19 x20 x21 x22 x23 x24 x25 x26 x27 x28 x29 lr sp pc
> 
> It's also now possible to record subsets of registers on aarch64:
> 
>   -> ./perf record --user-regs=x4,x5 ls
>   -> ./perf report --dump-raw-trace
> 
>   12801163749305260 0xc70 [0x40]: PERF_RECORD_SAMPLE(IP, 0x2): 51956/51956: 0xffffaa6571f0 period: 145785 addr: 0
>   ... user regs: mask 0x30 ABI 64-bit
>   .... x4    0x000000000000006c
>   .... x5    0x0000001001000001
>    ... thread: ls:51956
>     ...... dso: /usr/lib64/ld-2.17.so

Reviewed-by: Leo Yan <leo.yan@...aro.org>

Except this patch for enabling registers on aarch64, it's good to add
arm32's version in the file arch/arm/util/perf_regs.c.

Just note for a side topic, I checked a bit for the implementation for
x86/powerpc, you could consider to enable Statically Defined Tracing
in the perf_regs.c file as well.  This can be separate task for
arm/arm64.

Thanks,
Leo

> Cc: John Garry <john.garry@...wei.com>
> Cc: Leo Yan <leo.yan@...aro.org>
> Cc: Arnaldo Carvalho de Melo <acme@...nel.org>
> Cc: Jiri Olsa <jolsa@...hat.com>
> Cc: Namhyung Kim <namhyung@...nel.org>
> Signed-off-by: Alexandre Truong <alexandre.truong@....com>
> ---
>  tools/perf/arch/arm64/util/perf_regs.c | 33 ++++++++++++++++++++++++++
>  1 file changed, 33 insertions(+)
> 
> diff --git a/tools/perf/arch/arm64/util/perf_regs.c b/tools/perf/arch/arm64/util/perf_regs.c
> index 2833e101a..54efa12fd 100644
> --- a/tools/perf/arch/arm64/util/perf_regs.c
> +++ b/tools/perf/arch/arm64/util/perf_regs.c
> @@ -2,5 +2,38 @@
>  #include "../../../util/perf_regs.h"
>  
>  const struct sample_reg sample_reg_masks[] = {
> +	SMPL_REG(x0, PERF_REG_ARM64_X0),
> +	SMPL_REG(x1, PERF_REG_ARM64_X1),
> +	SMPL_REG(x2, PERF_REG_ARM64_X2),
> +	SMPL_REG(x3, PERF_REG_ARM64_X3),
> +	SMPL_REG(x4, PERF_REG_ARM64_X4),
> +	SMPL_REG(x5, PERF_REG_ARM64_X5),
> +	SMPL_REG(x6, PERF_REG_ARM64_X6),
> +	SMPL_REG(x7, PERF_REG_ARM64_X7),
> +	SMPL_REG(x8, PERF_REG_ARM64_X8),
> +	SMPL_REG(x9, PERF_REG_ARM64_X9),
> +	SMPL_REG(x10, PERF_REG_ARM64_X10),
> +	SMPL_REG(x11, PERF_REG_ARM64_X11),
> +	SMPL_REG(x12, PERF_REG_ARM64_X12),
> +	SMPL_REG(x13, PERF_REG_ARM64_X13),
> +	SMPL_REG(x14, PERF_REG_ARM64_X14),
> +	SMPL_REG(x15, PERF_REG_ARM64_X15),
> +	SMPL_REG(x16, PERF_REG_ARM64_X16),
> +	SMPL_REG(x17, PERF_REG_ARM64_X17),
> +	SMPL_REG(x18, PERF_REG_ARM64_X18),
> +	SMPL_REG(x19, PERF_REG_ARM64_X19),
> +	SMPL_REG(x20, PERF_REG_ARM64_X20),
> +	SMPL_REG(x21, PERF_REG_ARM64_X21),
> +	SMPL_REG(x22, PERF_REG_ARM64_X22),
> +	SMPL_REG(x23, PERF_REG_ARM64_X23),
> +	SMPL_REG(x24, PERF_REG_ARM64_X24),
> +	SMPL_REG(x25, PERF_REG_ARM64_X25),
> +	SMPL_REG(x26, PERF_REG_ARM64_X26),
> +	SMPL_REG(x27, PERF_REG_ARM64_X27),
> +	SMPL_REG(x28, PERF_REG_ARM64_X28),
> +	SMPL_REG(x29, PERF_REG_ARM64_X29),
> +	SMPL_REG(lr, PERF_REG_ARM64_LR),
> +	SMPL_REG(sp, PERF_REG_ARM64_SP),
> +	SMPL_REG(pc, PERF_REG_ARM64_PC),
>  	SMPL_REG_END
>  };
> -- 
> 2.23.0
>