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Commit a72a8a5f authored by David S. Miller's avatar David S. Miller
Browse files

sparc64: Add a basic conflict engine in preparation for multi-counter support. 



The hardware counter ->event_base state records and encoding of
the "struct perf_event_map" entry used for the event.

We use this to make sure that when we have more than 1 event,
both can be scheduled into the hardware at the same time.

As usual, structure of code is largely cribbed from powerpc.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1b6b9d62

arch/sparc/kernel/perf_event.c

+64 −5
Original line number Diff line number Diff line
@@ -68,6 +68,17 @@ struct perf_event_map { 
#define PIC_LOWER	0x02

};



static unsigned long perf_event_encode(const struct perf_event_map *pmap)

{

	return ((unsigned long) pmap->encoding << 16) | pmap->pic_mask;

}



static void perf_event_decode(unsigned long val, u16 *enc, u8 *msk)

{

	*msk = val & 0xff;

	*enc = val >> 16;

}



#define C(x) PERF_COUNT_HW_CACHE_##x



#define CACHE_OP_UNSUPPORTED	0xfffe
@@ -713,6 +724,48 @@ static void hw_perf_event_destroy(struct perf_event *event) 
	perf_event_release_pmc();

}



/* Make sure all events can be scheduled into the hardware at

 * the same time.  This is simplified by the fact that we only

 * need to support 2 simultaneous HW events.

 */

static int sparc_check_constraints(unsigned long *events, int n_ev)

{

	if (n_ev <= perf_max_events) {

		u8 msk1, msk2;

		u16 dummy;



		if (n_ev == 1)

			return 0;

		BUG_ON(n_ev != 2);

		perf_event_decode(events[0], &dummy, &msk1);

		perf_event_decode(events[1], &dummy, &msk2);



		/* If both events can go on any counter, OK.  */

		if (msk1 == (PIC_UPPER | PIC_LOWER) &&

		    msk2 == (PIC_UPPER | PIC_LOWER))

			return 0;



		/* If one event is limited to a specific counter,

		 * and the other can go on both, OK.

		 */

		if ((msk1 == PIC_UPPER || msk1 == PIC_LOWER) &&

		    msk2 == (PIC_UPPER | PIC_LOWER))

			return 0;

		if ((msk2 == PIC_UPPER || msk2 == PIC_LOWER) &&

		    msk1 == (PIC_UPPER | PIC_LOWER))

			return 0;



		/* If the events are fixed to different counters, OK.  */

		if ((msk1 == PIC_UPPER && msk2 == PIC_LOWER) ||

		    (msk1 == PIC_LOWER && msk2 == PIC_UPPER))

			return 0;



		/* Otherwise, there is a conflict.  */

	}



	return -1;

}



static int check_excludes(struct perf_event **evts, int n_prev, int n_new)

{

	int eu = 0, ek = 0, eh = 0;
@@ -742,7 +795,7 @@ static int check_excludes(struct perf_event **evts, int n_prev, int n_new) 
}



static int collect_events(struct perf_event *group, int max_count,

			  struct perf_event *evts[], u64 *events)

			  struct perf_event *evts[], unsigned long *events)

{

	struct perf_event *event;

	int n = 0;
@@ -751,7 +804,7 @@ static int collect_events(struct perf_event *group, int max_count, 
		if (n >= max_count)

			return -1;

		evts[n] = group;

		events[n++] = group->hw.config;

		events[n++] = group->hw.event_base;

	}

	list_for_each_entry(event, &group->sibling_list, group_entry) {

		if (!is_software_event(event) &&
@@ -759,7 +812,7 @@ static int collect_events(struct perf_event *group, int max_count, 
			if (n >= max_count)

				return -1;

			evts[n] = event;

			events[n++] = event->hw.config;

			events[n++] = event->hw.event_base;

		}

	}

	return n;
@@ -770,8 +823,9 @@ static int __hw_perf_event_init(struct perf_event *event) 
	struct perf_event_attr *attr = &event->attr;

	struct perf_event *evts[MAX_HWEVENTS];

	struct hw_perf_event *hwc = &event->hw;

	unsigned long events[MAX_HWEVENTS];

	const struct perf_event_map *pmap;

	u64 enc, events[MAX_HWEVENTS];

	u64 enc;

	int n;



	if (atomic_read(&nmi_active) < 0)
@@ -800,6 +854,8 @@ static int __hw_perf_event_init(struct perf_event *event) 
	if (!attr->exclude_hv)

		hwc->config_base |= sparc_pmu->hv_bit;



	hwc->event_base = perf_event_encode(pmap);



	enc = pmap->encoding;



	n = 0;
@@ -810,12 +866,15 @@ static int __hw_perf_event_init(struct perf_event *event) 
		if (n < 0)

			return -EINVAL;

	}

	events[n] = enc;

	events[n] = hwc->event_base;

	evts[n] = event;



	if (check_excludes(evts, n, 1))

		return -EINVAL;



	if (sparc_check_constraints(events, n + 1))

		return -EINVAL;



	/* Try to do all error checking before this point, as unwinding

	 * state after grabbing the PMC is difficult.

	 */