On Wed, 9 Aug 2023 16:18:25 +0800
Yicong Yang <yangyicong@xxxxxxxxxx> 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.
>
> 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 916686c6a9c8..7392e039b8c1 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);
