On 14/09/2023 12:22, Yicong Yang wrote:
From: Junhao He <hejunhao3@xxxxxxxxxx>
When start trace with perf option "-C $cpu" and immediately stop it
with SIGTERM or others, the perf core will invoke pmu::read() while
the driver doesn't implement it. Add a dummy pmu::read() to avoid
any issues.
What issues are we talking about here ? Shouldn't the core perf
skip the call, if pmu::read() is not available ?
Suzuki
Signed-off-by: Junhao He <hejunhao3@xxxxxxxxxx>
Signed-off-by: Yicong Yang <yangyicong@xxxxxxxxxxxxx>
Acked-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
---
drivers/hwtracing/ptt/hisi_ptt.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/hwtracing/ptt/hisi_ptt.c b/drivers/hwtracing/ptt/hisi_ptt.c
index 62a444f5228e..c1b5fd2b8974 100644
--- a/drivers/hwtracing/ptt/hisi_ptt.c
+++ b/drivers/hwtracing/ptt/hisi_ptt.c
@@ -1184,6 +1184,10 @@ static void hisi_ptt_pmu_del(struct perf_event *event, int flags)
hisi_ptt_pmu_stop(event, PERF_EF_UPDATE);
}
+static void hisi_ptt_pmu_read(struct perf_event *event)
+{
+}
+
static void hisi_ptt_remove_cpuhp_instance(void *hotplug_node)
{
cpuhp_state_remove_instance_nocalls(hisi_ptt_pmu_online, hotplug_node);
@@ -1227,6 +1231,7 @@ static int hisi_ptt_register_pmu(struct hisi_ptt *hisi_ptt)
.stop = hisi_ptt_pmu_stop,
.add = hisi_ptt_pmu_add,
.del = hisi_ptt_pmu_del,
+ .read = hisi_ptt_pmu_read,
};
reg = readl(hisi_ptt->iobase + HISI_PTT_LOCATION);
