[PATCH 03/13] drivers/perf: apple_m1: Support per-implementation event tables

Myria Sarvay via B4 Relay devnull+myrialsarvay.gmail.com at kernel.org
Tue Nov 3 02:14:38 PST 2026


From: Nick Chan <towinchenmi at gmail.com>

Use per-implementation event tables to allow supporting implementations
with a different list of events and event affinities.

Signed-off-by: Nick Chan <towinchenmi at gmail.com>
Co-developed-by: Myria Sarvay <myrialsarvay at gmail.com>
Signed-off-by: Myria Sarvay <myrialsarvay at gmail.com>
---
 drivers/perf/apple_m1_cpu_pmu.c | 113 ++++++++++++++++++++++++----------------
 1 file changed, 69 insertions(+), 44 deletions(-)

diff --git a/drivers/perf/apple_m1_cpu_pmu.c b/drivers/perf/apple_m1_cpu_pmu.c
index de4026c63afd..2ff0c2e0b737 100644
--- a/drivers/perf/apple_m1_cpu_pmu.c
+++ b/drivers/perf/apple_m1_cpu_pmu.c
@@ -43,9 +43,6 @@
  * moment, we don't really need to distinguish between the two because we
  * know next to nothing about the events themselves, and we already have
  * per cpu-type PMU abstractions.
- *
- * If we eventually find out that the events are different across
- * implementations, we'll have to introduce per cpu-type tables.
  */
 enum m1_pmu_events {
 	M1_PMU_PERFCTR_RETIRE_UOP				= 0x1,
@@ -167,7 +164,7 @@ static const u16 m1_pmu_event_affinity[M1_PMU_PERFCTR_LAST + 1] = {
 	[M1_PMU_PERFCTR_UNKNOWN_fd]				= ONLY_2_4_6,
 };
 
-static const unsigned m1_pmu_perf_map[PERF_COUNT_HW_MAX] = {
+static const unsigned int m1_pmu_perf_map[PERF_COUNT_HW_MAX] = {
 	PERF_MAP_ALL_UNSUPPORTED,
 	[PERF_COUNT_HW_CPU_CYCLES]		= M1_PMU_PERFCTR_CORE_ACTIVE_CYCLE,
 	[PERF_COUNT_HW_INSTRUCTIONS]		= M1_PMU_PERFCTR_INST_ALL,
@@ -486,11 +483,12 @@ static void m1_pmu_write_counter(struct perf_event *event, u64 value)
 	isb();
 }
 
-static int m1_pmu_get_event_idx(struct pmu_hw_events *cpuc,
-				struct perf_event *event)
+static int apple_pmu_get_event_idx(struct pmu_hw_events *cpuc,
+				   struct perf_event *event,
+				   const u16 event_affinities[])
 {
 	unsigned long evtype = event->hw.config_base & M1_PMU_CFG_EVENT;
-	unsigned long affinity = m1_pmu_event_affinity[evtype];
+	unsigned long affinity = event_affinities[evtype];
 	int idx;
 
 	/*
@@ -509,6 +507,12 @@ static int m1_pmu_get_event_idx(struct pmu_hw_events *cpuc,
 	return -EAGAIN;
 }
 
+static int m1_pmu_get_event_idx(struct pmu_hw_events *cpuc,
+				struct perf_event *event)
+{
+	return apple_pmu_get_event_idx(cpuc, event, m1_pmu_event_affinity);
+}
+
 static void m1_pmu_clear_event_idx(struct pmu_hw_events *cpuc,
 				   struct perf_event *event)
 {
@@ -536,44 +540,52 @@ static void m1_pmu_stop(struct arm_pmu *cpu_pmu)
 	__m1_pmu_set_mode(PMCR0_IMODE_OFF);
 }
 
+static int apple_pmu_map_event(struct perf_event *event,
+			       const unsigned int (*perf_map)[],
+			       unsigned int flags)
+{
+	event->hw.flags |= flags;
+	return armpmu_map_event(event, perf_map, NULL, M1_PMU_CFG_EVENT);
+}
+
+/*
+ * Apple PMU counters have been observed to be either 48 or
+ * 64 bits wide, depending on the SoC. However, the MSB is
+ * what triggers an overflow interrupt, so we advertise the
+ * counters as being 1-bit smaller than hardware so as to
+ * mimick ARM PMU behaviour
+ */
 static int m1_pmu_map_event(struct perf_event *event)
 {
-	/*
-	 * Although the counters are 48bit wide, bit 47 is what
-	 * triggers the overflow interrupt. Advertise the counters
-	 * being 47bit wide to mimick the behaviour of the ARM PMU.
-	 */
-	event->hw.flags |= ARMPMU_EVT_47BIT;
-	return armpmu_map_event(event, &m1_pmu_perf_map, NULL, M1_PMU_CFG_EVENT);
+	return apple_pmu_map_event(event, &m1_pmu_perf_map, ARMPMU_EVT_47BIT);
 }
 
 static int m2_pmu_map_event(struct perf_event *event)
 {
-	/*
-	 * Same deal as the above, except that M2 has 64bit counters.
-	 * Which, as far as we're concerned, actually means 63 bits.
-	 * Yes, this is getting awkward.
-	 */
-	event->hw.flags |= ARMPMU_EVT_63BIT;
-	return armpmu_map_event(event, &m1_pmu_perf_map, NULL, M1_PMU_CFG_EVENT);
+	return apple_pmu_map_event(event, &m1_pmu_perf_map, ARMPMU_EVT_63BIT);
 }
 
-static int m1_pmu_map_pmuv3_event(unsigned int eventsel)
+static int apple_pmu_map_pmuv3_event(unsigned int eventsel, const u16 pmceid_map[])
 {
-	u16 m1_event = HW_OP_UNSUPPORTED;
+	u16 apple_event = HW_OP_UNSUPPORTED;
 
 	if (eventsel < ARMV8_PMUV3_MAX_COMMON_EVENTS)
-		m1_event = m1_pmu_pmceid_map[eventsel];
+		apple_event = pmceid_map[eventsel];
 
-	return m1_event == HW_OP_UNSUPPORTED ? -EOPNOTSUPP : m1_event;
+	return apple_event == HW_OP_UNSUPPORTED ? -EOPNOTSUPP : apple_event;
 }
 
-static void m1_pmu_init_pmceid(struct arm_pmu *pmu)
+static int m1_pmu_map_pmuv3_event(unsigned int eventsel)
+{
+	return apple_pmu_map_pmuv3_event(eventsel, m1_pmu_pmceid_map);
+}
+
+static void apple_pmu_init_pmceid(struct arm_pmu *pmu)
 {
 	unsigned int event;
 
 	for (event = 0; event < ARMV8_PMUV3_MAX_COMMON_EVENTS; event++) {
-		if (m1_pmu_map_pmuv3_event(event) >= 0)
+		if (pmu->map_pmuv3_event(event) >= 0)
 			set_bit(event, pmu->pmceid_bitmap);
 	}
 }
@@ -616,33 +628,22 @@ static int m1_pmu_set_event_filter(struct hw_perf_event *event,
 	return 0;
 }
 
-static int m1_pmu_init(struct arm_pmu *cpu_pmu, u32 flags)
+static int apple_pmu_init(struct arm_pmu *cpu_pmu)
 {
 	cpu_pmu->handle_irq	  = m1_pmu_handle_irq;
 	cpu_pmu->enable		  = m1_pmu_enable_event;
 	cpu_pmu->disable	  = m1_pmu_disable_event;
 	cpu_pmu->read_counter	  = m1_pmu_read_counter;
 	cpu_pmu->write_counter	  = m1_pmu_write_counter;
-	cpu_pmu->get_event_idx	  = m1_pmu_get_event_idx;
 	cpu_pmu->clear_event_idx  = m1_pmu_clear_event_idx;
 	cpu_pmu->start		  = m1_pmu_start;
 	cpu_pmu->stop		  = m1_pmu_stop;
-
-	if (flags & ARMPMU_EVT_47BIT)
-		cpu_pmu->map_event = m1_pmu_map_event;
-	else if (flags & ARMPMU_EVT_63BIT)
-		cpu_pmu->map_event = m2_pmu_map_event;
-	else
-		return WARN_ON(-EINVAL);
-
 	cpu_pmu->reset		  = m1_pmu_reset;
 	cpu_pmu->set_event_filter = m1_pmu_set_event_filter;
 
-	cpu_pmu->map_pmuv3_event  = m1_pmu_map_pmuv3_event;
-	m1_pmu_init_pmceid(cpu_pmu);
+	apple_pmu_init_pmceid(cpu_pmu);
 
 	bitmap_set(cpu_pmu->cntr_mask, 0, M1_PMU_NR_COUNTERS);
-	cpu_pmu->attr_groups[ARMPMU_ATTR_GROUP_EVENTS] = &m1_pmu_events_attr_group;
 	cpu_pmu->attr_groups[ARMPMU_ATTR_GROUP_FORMATS] = &m1_pmu_format_attr_group;
 	return 0;
 }
@@ -651,25 +652,49 @@ static int m1_pmu_init(struct arm_pmu *cpu_pmu, u32 flags)
 static int m1_pmu_ice_init(struct arm_pmu *cpu_pmu)
 {
 	cpu_pmu->name = "apple_icestorm_pmu";
-	return m1_pmu_init(cpu_pmu, ARMPMU_EVT_47BIT);
+	cpu_pmu->get_event_idx	  = m1_pmu_get_event_idx;
+	cpu_pmu->map_event	  = m1_pmu_map_event;
+
+	cpu_pmu->map_pmuv3_event  = m1_pmu_map_pmuv3_event;
+
+	cpu_pmu->attr_groups[ARMPMU_ATTR_GROUP_EVENTS] = &m1_pmu_events_attr_group;
+	return apple_pmu_init(cpu_pmu);
 }
 
 static int m1_pmu_fire_init(struct arm_pmu *cpu_pmu)
 {
 	cpu_pmu->name = "apple_firestorm_pmu";
-	return m1_pmu_init(cpu_pmu, ARMPMU_EVT_47BIT);
+	cpu_pmu->get_event_idx	  = m1_pmu_get_event_idx;
+	cpu_pmu->map_event	  = m1_pmu_map_event;
+
+	cpu_pmu->map_pmuv3_event  = m1_pmu_map_pmuv3_event;
+
+	cpu_pmu->attr_groups[ARMPMU_ATTR_GROUP_EVENTS] = &m1_pmu_events_attr_group;
+	return apple_pmu_init(cpu_pmu);
 }
 
 static int m2_pmu_avalanche_init(struct arm_pmu *cpu_pmu)
 {
 	cpu_pmu->name = "apple_avalanche_pmu";
-	return m1_pmu_init(cpu_pmu, ARMPMU_EVT_63BIT);
+	cpu_pmu->get_event_idx	  = m1_pmu_get_event_idx;
+	cpu_pmu->map_event	  = m2_pmu_map_event;
+
+	cpu_pmu->map_pmuv3_event  = m1_pmu_map_pmuv3_event;
+
+	cpu_pmu->attr_groups[ARMPMU_ATTR_GROUP_EVENTS] = &m1_pmu_events_attr_group;
+	return apple_pmu_init(cpu_pmu);
 }
 
 static int m2_pmu_blizzard_init(struct arm_pmu *cpu_pmu)
 {
 	cpu_pmu->name = "apple_blizzard_pmu";
-	return m1_pmu_init(cpu_pmu, ARMPMU_EVT_63BIT);
+	cpu_pmu->get_event_idx	  = m1_pmu_get_event_idx;
+	cpu_pmu->map_event	  = m2_pmu_map_event;
+
+	cpu_pmu->map_pmuv3_event  = m1_pmu_map_pmuv3_event;
+
+	cpu_pmu->attr_groups[ARMPMU_ATTR_GROUP_EVENTS] = &m1_pmu_events_attr_group;
+	return apple_pmu_init(cpu_pmu);
 }
 
 static const struct of_device_id m1_pmu_of_device_ids[] = {

-- 
2.56.0





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