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Message-ID: <Z9jNOgbZj_ZCx-9-@google.com>
Date: Mon, 17 Mar 2025 18:32:42 -0700
From: Namhyung Kim <namhyung@...nel.org>
To: Li Huafei <lihuafei1@...wei.com>
Cc: acme@...nel.org, leo.yan@...ux.dev, james.clark@...aro.org,
mark.rutland@....com, john.g.garry@...cle.com, will@...nel.org,
irogers@...gle.com, mike.leach@...aro.org, peterz@...radead.org,
mingo@...hat.com, alexander.shishkin@...ux.intel.com,
jolsa@...nel.org, kjain@...ux.ibm.com, mhiramat@...nel.org,
atrajeev@...ux.vnet.ibm.com, sesse@...gle.com,
adrian.hunter@...el.com, kan.liang@...ux.intel.com,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-perf-users@...r.kernel.org
Subject: Re: [PATCH 1/7] perf annotate: Handle arm64 load and store
instructions
On Sat, Mar 15, 2025 at 12:21:31AM +0800, Li Huafei wrote:
> Add ldst_ops to handle load and store instructions in order to parse
> the data types and offsets associated with PMU events for memory access
> instructions. There are many variants of load and store instructions in
> ARM64, making it difficult to match all of these instruction names
> completely. Therefore, only the instruction prefixes are matched. The
> prefix 'ld|st' covers most of the memory access instructions, 'cas|swp'
> matches atomic instructions, and 'prf' matches memory prefetch
> instructions.
>
> Signed-off-by: Li Huafei <lihuafei1@...wei.com>
> ---
> tools/perf/arch/arm64/annotate/instructions.c | 67 ++++++++++++++++++-
> 1 file changed, 66 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/arch/arm64/annotate/instructions.c b/tools/perf/arch/arm64/annotate/instructions.c
> index d465d093e7eb..c212eb7341bd 100644
> --- a/tools/perf/arch/arm64/annotate/instructions.c
> +++ b/tools/perf/arch/arm64/annotate/instructions.c
> @@ -6,7 +6,8 @@
>
> struct arm64_annotate {
> regex_t call_insn,
> - jump_insn;
> + jump_insn,
> + ldst_insn; /* load and store instruction */
> };
>
> static int arm64_mov__parse(struct arch *arch __maybe_unused,
> @@ -67,6 +68,57 @@ static struct ins_ops arm64_mov_ops = {
> .scnprintf = mov__scnprintf,
> };
>
> +static int arm64_ldst__parse(struct arch *arch __maybe_unused,
> + struct ins_operands *ops,
> + struct map_symbol *ms __maybe_unused,
> + struct disasm_line *dl __maybe_unused)
> +{
> + char *s, *target;
> +
> + /*
> + * The part starting from the memory access annotation '[' is parsed
> + * as 'target', while the part before it is parsed as 'source'.
> + */
> + target = s = strchr(ops->raw, '[');
> + if (!s)
> + return -1;
> +
> + while (s > ops->raw && *s != ',')
> + --s;
> +
> + if (s == ops->raw)
> + return -1;
> +
> + *s = '\0';
> + ops->source.raw = strdup(ops->raw);
> +
> + *s = ',';
> + if (!ops->source.raw)
> + return -1;
> +
> + ops->target.raw = strdup(target);
> + if (!ops->target.raw) {
> + zfree(ops->source.raw);
I think you need 'zfree(&ops->source.raw)' instead.
> + return -1;
> + }
> + ops->target.mem_ref = true;
> +
> + return 0;
> +}
> +
> +static int ldst__scnprintf(struct ins *ins, char *bf, size_t size,
> + struct ins_operands *ops, int max_ins_name)
> +{
> + return scnprintf(bf, size, "%-*s %s,%s", max_ins_name, ins->name,
> + ops->source.name ?: ops->source.raw,
> + ops->target.name ?: ops->target.raw);
> +}
> +
> +static struct ins_ops arm64_ldst_ops = {
> + .parse = arm64_ldst__parse,
> + .scnprintf = ldst__scnprintf,
> +};
> +
> static struct ins_ops *arm64__associate_instruction_ops(struct arch *arch, const char *name)
> {
> struct arm64_annotate *arm = arch->priv;
> @@ -77,6 +129,8 @@ static struct ins_ops *arm64__associate_instruction_ops(struct arch *arch, const
> ops = &jump_ops;
> else if (!regexec(&arm->call_insn, name, 2, match, 0))
> ops = &call_ops;
> + else if (!regexec(&arm->ldst_insn, name, 2, match, 0))
> + ops = &arm64_ldst_ops;
> else if (!strcmp(name, "ret"))
> ops = &ret_ops;
> else
> @@ -107,6 +161,15 @@ static int arm64__annotate_init(struct arch *arch, char *cpuid __maybe_unused)
> REG_EXTENDED);
> if (err)
> goto out_free_call;
> + /*
> + * The ARM64 architecture has many variants of load/store instructions.
> + * It is quite challenging to match all of them completely. Here, we
> + * only match the prefixes of these instructions.
> + */
> + err = regcomp(&arm->ldst_insn, "^(ld|st|cas|prf|swp)",
> + REG_EXTENDED);
> + if (err)
> + goto out_free_jump;
>
> arch->initialized = true;
> arch->priv = arm;
> @@ -117,6 +180,8 @@ static int arm64__annotate_init(struct arch *arch, char *cpuid __maybe_unused)
> arch->e_flags = 0;
> return 0;
>
> +out_free_jump:
> + regfree(&arm->jump_insn);
> out_free_call:
> regfree(&arm->call_insn);
It seems we leak these on the success path. Probably we need arch
annotate_exit() to free the resources.
Thanks,
Namhyung
> out_free_arm:
> --
> 2.25.1
>
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