hwtracing: hisi_ptt: Add dummy callback pmu::read()

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.

Fixes: ff0de066b463 ("hwtracing: hisi_ptt: Add trace function support for HiSilicon PCIe Tune and Trace device")
Signed-off-by: Junhao He <hejunhao3@huawei.com>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20231010084731.30450-6-yangyicong@huawei.com

diff --git a/drivers/hwtracing/ptt/hisi_ptt.c b/drivers/hwtracing/ptt/hisi_ptt.c
index 49ea1b0f7489035211c51b753b9de3f0166c70fd..3045d1894b81bb584dfb251db676186b13ad2329 100644 (file)
--- a/drivers/hwtracing/ptt/hisi_ptt.c
+++ b/drivers/hwtracing/ptt/hisi_ptt.c
@@ -1178,6 +1178,10 @@ 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);
@@ -1221,6 +1225,7 @@ 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);