linux-kernel - Re: [PATCH v5 08/13] coresight: Interpret perf config with ATTR_CFG_GET

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAJ9a7VgQH4yc8490CQSv1S6k+=Uc6dEjyEpgRp1EwUQdwdxOHQ@mail.gmail.com>
Date: Wed, 19 Nov 2025 09:32:50 +0000
From: Mike Leach <mike.leach@...aro.org>
To: James Clark <james.clark@...aro.org>
Cc: Suzuki K Poulose <suzuki.poulose@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jonathan Corbet <corbet@....net>, 
	Leo Yan <leo.yan@....com>, Randy Dunlap <rdunlap@...radead.org>, coresight@...ts.linaro.org, 
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	linux-doc@...r.kernel.org
Subject: Re: [PATCH v5 08/13] coresight: Interpret perf config with ATTR_CFG_GET_FLD()

Hi James

On Tue, 18 Nov 2025 at 16:28, James Clark <james.clark@...aro.org> wrote:
>
> The "config:" string construction in format_attr_contextid_show() can be
> removed because it either showed the existing context1 or context2
> formats which have already been generated, so can be called themselves.
>
> The other conversions are straightforward replacements.
>
> Signed-off-by: James Clark <james.clark@...aro.org>
> ---
>  drivers/hwtracing/coresight/coresight-etm-perf.c | 26 +++++++++++++++---------
>  1 file changed, 16 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
> index 28f1bfc4579f..1b9ae832a576 100644
> --- a/drivers/hwtracing/coresight/coresight-etm-perf.c
> +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
> @@ -80,12 +80,19 @@ static ssize_t format_attr_contextid_show(struct device *dev,
>                                           struct device_attribute *attr,
>                                           char *page)
>  {
> -       int pid_fmt = ETM_OPT_CTXTID;
> +       /*
> +        * is_kernel_in_hyp_mode() isn't defined in arm32 so avoid calling it
> +        * even though is_visible() prevents this function from being called.
> +        */
> +#if IS_ENABLED(CONFIG_ARM64)
> +       if (is_kernel_in_hyp_mode())
> +               return contextid2_show(dev, attr, page);
>
> -#if IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM4X)
> -       pid_fmt = is_kernel_in_hyp_mode() ? ETM_OPT_CTXTID2 : ETM_OPT_CTXTID;
> +       return contextid1_show(dev, attr, page);
> +#else
> +       WARN_ONCE(1, "ETM contextid not supported on arm32\n");
> +       return 0;

Context ID is supported in aarch32 - and traced in etmv3 / ptm and etmv4.

Mike

>  #endif
> -       return sprintf(page, "config:%d\n", pid_fmt);
>  }
>
>  static struct device_attribute format_attr_contextid =
> @@ -337,7 +344,7 @@ static bool sinks_compatible(struct coresight_device *a,
>  static void *etm_setup_aux(struct perf_event *event, void **pages,
>                            int nr_pages, bool overwrite)
>  {
> -       u32 id, cfg_hash;
> +       u32 sink_hash, cfg_hash;
>         int cpu = event->cpu;
>         cpumask_t *mask;
>         struct coresight_device *sink = NULL;
> @@ -350,13 +357,12 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
>         INIT_WORK(&event_data->work, free_event_data);
>
>         /* First get the selected sink from user space. */
> -       if (event->attr.config2 & GENMASK_ULL(31, 0)) {
> -               id = (u32)event->attr.config2;
> -               sink = user_sink = coresight_get_sink_by_id(id);
> -       }
> +       sink_hash = ATTR_CFG_GET_FLD(&event->attr, sinkid);
> +       if (sink_hash)
> +               sink = user_sink = coresight_get_sink_by_id(sink_hash);
>
>         /* check if user wants a coresight configuration selected */
> -       cfg_hash = (u32)((event->attr.config2 & GENMASK_ULL(63, 32)) >> 32);
> +       cfg_hash = ATTR_CFG_GET_FLD(&event->attr, configid);
>         if (cfg_hash) {
>                 if (cscfg_activate_config(cfg_hash))
>                         goto err;
>
> --
> 2.34.1
>


-- 
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK