Commit 6a82e23f authored by Thomas Richter's avatar Thomas Richter Committed by Vasily Gorbik
Browse files

s390/cpumf: Adjust registration of s390 PMU device drivers 



Linux-next commit titled "perf/core: Optimize perf_init_event()"
changed the semantics of PMU device driver registration.
It was done to speed up the lookup/handling of PMU device driver
specific events. It also enforces that only one PMU device
driver will be registered of type PERF_EVENT_RAW.

This change added these line in function perf_pmu_register():

  ...
  +       ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
  +       if (ret < 0)
                goto free_pdc;
  +
  +       WARN_ON(type >= 0 && ret != type);

The warn_on generates a message. We have 3 PMU device drivers,
each registered as type PERF_TYPE_RAW.
The cf_diag device driver (arch/s390/kernel/perf_cpumf_cf_diag.c)
always hits the WARN_ON because it is the second PMU device driver
(after sampling device driver arch/s390/kernel/perf_cpumf_sf.c)
which is registered as type 4 (PERF_TYPE_RAW).
So when the sampling device driver is registered, ret has value 4.
When cf_diag device driver is registered with type 4,
ret has value of 5 and WARN_ON fires.

Adjust the PMU device drivers for s390 to support the new
semantics required by perf_pmu_register().

Signed-off-by: default avatarThomas Richter <tmricht@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent 72a81ad9

arch/s390/kernel/perf_cpum_cf.c

+10 −11
Original line number Diff line number Diff line
@@ -199,7 +199,7 @@ static const int cpumf_generic_events_user[] = { 
	[PERF_COUNT_HW_BUS_CYCLES]	    = -1,

};



static int __hw_perf_event_init(struct perf_event *event)

static int __hw_perf_event_init(struct perf_event *event, unsigned int type)

{

	struct perf_event_attr *attr = &event->attr;

	struct hw_perf_event *hwc = &event->hw;
@@ -207,7 +207,7 @@ static int __hw_perf_event_init(struct perf_event *event) 
	int err = 0;

	u64 ev;



	switch (attr->type) {

	switch (type) {

	case PERF_TYPE_RAW:

		/* Raw events are used to access counters directly,

		 * hence do not permit excludes */
@@ -294,17 +294,16 @@ static int __hw_perf_event_init(struct perf_event *event) 


static int cpumf_pmu_event_init(struct perf_event *event)

{

	unsigned int type = event->attr.type;

	int err;



	switch (event->attr.type) {

	case PERF_TYPE_HARDWARE:

	case PERF_TYPE_HW_CACHE:

	case PERF_TYPE_RAW:

		err = __hw_perf_event_init(event);

		break;

	default:

	if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_RAW)

		err = __hw_perf_event_init(event, type);

	else if (event->pmu->type == type)

		/* Registered as unknown PMU */

		err = __hw_perf_event_init(event, PERF_TYPE_RAW);

	else

		return -ENOENT;

	}



	if (unlikely(err) && event->destroy)

		event->destroy(event);
@@ -553,7 +552,7 @@ static int __init cpumf_pmu_init(void) 
		return -ENODEV;



	cpumf_pmu.attr_groups = cpumf_cf_event_group();

	rc = perf_pmu_register(&cpumf_pmu, "cpum_cf", PERF_TYPE_RAW);

	rc = perf_pmu_register(&cpumf_pmu, "cpum_cf", -1);

	if (rc)

		pr_err("Registering the cpum_cf PMU failed with rc=%i\n", rc);

	return rc;

arch/s390/kernel/perf_cpum_cf_diag.c

+5 −5
Original line number Diff line number Diff line
@@ -243,13 +243,13 @@ static int cf_diag_event_init(struct perf_event *event) 
	int err = -ENOENT;



	debug_sprintf_event(cf_diag_dbg, 5,

			    "%s event %p cpu %d config %#llx "

			    "%s event %p cpu %d config %#llx type:%u "

			    "sample_type %#llx cf_diag_events %d\n", __func__,

			    event, event->cpu, attr->config, attr->sample_type,

			    atomic_read(&cf_diag_events));

			    event, event->cpu, attr->config, event->pmu->type,

			    attr->sample_type, atomic_read(&cf_diag_events));



	if (event->attr.config != PERF_EVENT_CPUM_CF_DIAG ||

	    event->attr.type != PERF_TYPE_RAW)

	    event->attr.type != event->pmu->type)

		goto out;



	/* Raw events are used to access counters directly,
@@ -693,7 +693,7 @@ static int __init cf_diag_init(void) 
	}

	debug_register_view(cf_diag_dbg, &debug_sprintf_view);



	rc = perf_pmu_register(&cf_diag, "cpum_cf_diag", PERF_TYPE_RAW);

	rc = perf_pmu_register(&cf_diag, "cpum_cf_diag", -1);

	if (rc) {

		debug_unregister_view(cf_diag_dbg, &debug_sprintf_view);

		debug_unregister(cf_diag_dbg);

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