On 14/11/2025 2:55 pm, Leo Yan wrote:
On Wed, Nov 12, 2025 at 03:22:10PM +0000, James Clark wrote:
ETMv3 only has a few attributes, and setting unused ones results in an error, so hide them to begin with.
Signed-off-by: James Clark james.clark@linaro.org
drivers/hwtracing/coresight/coresight-etm-perf.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+)
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c index 17afa0f4cdee..91132abca244 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.c +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c @@ -106,8 +106,27 @@ static struct attribute *etm_config_formats_attr[] = { NULL, }; +static umode_t etm_format_attr_is_visible(struct kobject *kobj,
struct attribute *attr, int unused)+{
- /* ETM4 has all attributes */
- if (IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM4X))
return attr->mode;- /* ETM3 only has these attributes */
- if (attr == &format_attr_cycacc.attr ||
attr == &format_attr_timestamp.attr ||attr == &format_attr_retstack.attr ||attr == &format_attr_sinkid.attr ||attr == &format_attr_configid.attr)Do we support configid for ETM3?
They're "activated" in etm_setup_aux() so this would be for both ETM3 and 4. But they're only subsequently "enabled" for ETM4. So no, they're not supported. I'll hide this attribute too.
I can leave it for a later fix if we want to stop activating them, but I don't think it does any harm.
return attr->mode;It is good to give a bit information why only these attributes supported, e.g.,
/* * ETM3 only support subset attributes (see ETM3X_SUPPORTED_OPTIONS), * keep 'sinkid' attr for specifying sink ID. */
Two side topics but not issues caused this patch:
- Since CTXTID/CTXTID2 is only used for ETM4x, we can remove "#if IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM4X)" from the format_attr_contextid_show() function.
Will change to CONFIG_ARM64 as mentioned on the other thread.
- etm_parse_event_config() does not check attr->config3, thus user sets 'cc_threshold' it will slip without any error report.
Will ignore this comment as mentioned on patch 7, we're not doing any errors for unsupported arguments anymore.
Thanks, Leo
- return 0;
+}
- static const struct attribute_group etm_pmu_format_group = { .name = "format",
- .is_visible = etm_format_attr_is_visible, .attrs = etm_config_formats_attr, };
-- 2.34.1