[PATCH v9 05/22] perf: arm_pmuv3: Move counter allocation mask to per-CPU struct pmu_hw_events

[Colton Lewis]

In preparation for dynamic per-CPU PMU counter reservations when running
KVM guests with a partitioned PMU, move the counter allocation mask from
the global struct arm_pmu to per-CPU struct pmu_hw_events.

Initialize cpuc->cntr_mask from the static cpu_pmu->cntr_mask during PMU
probe and CPU hotplug startup, and update event counter allocation
helpers (armv8pmu_get_single_idx(), armv8pmu_get_chain_idx(), and
armv8pmu_get_event_idx()) to query the per-CPU mask.

Signed-off-by: Colton Lewis <coltonlewis at google.com>
---
 drivers/perf/arm_pmu.c       |  7 ++++++-
 drivers/perf/arm_pmuv3.c     | 18 +++++++++++++-----
 include/linux/perf/arm_pmu.h |  1 +
 3 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 1150695653892..344adcd3521d0 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -408,9 +408,11 @@ validate_group(struct perf_event *event)
 
 	/*
 	 * Initialise the fake PMU. We only need to populate the
-	 * used_mask for the purposes of validation.
+	 * used_mask and cntr_mask for the purposes of validation.
 	 */
 	memset(&fake_pmu.used_mask, 0, sizeof(fake_pmu.used_mask));
+	bitmap_copy(fake_pmu.cntr_mask, to_arm_pmu(event->pmu)->cntr_mask,
+		    ARMPMU_MAX_HWEVENTS);
 
 	if (!validate_event(event->pmu, &fake_pmu, leader))
 		return -EINVAL;
@@ -717,6 +719,7 @@ bool arm_pmu_irq_is_nmi(void)
 static int arm_perf_starting_cpu(unsigned int cpu, struct hlist_node *node)
 {
 	struct arm_pmu *pmu = hlist_entry_safe(node, struct arm_pmu, node);
+	struct pmu_hw_events *cpuc = per_cpu_ptr(pmu->hw_events, cpu);
 	int irq;
 
 	if (!cpumask_test_cpu(cpu, &pmu->supported_cpus))
@@ -724,6 +727,8 @@ static int arm_perf_starting_cpu(unsigned int cpu, struct hlist_node *node)
 	if (pmu->reset)
 		pmu->reset(pmu);
 
+	bitmap_copy(cpuc->cntr_mask, pmu->cntr_mask, ARMPMU_MAX_HWEVENTS);
+
 	irq = armpmu_get_cpu_irq(pmu, cpu);
 	if (irq)
 		per_cpu(cpu_irq_ops, cpu)->enable_pmuirq(irq);
diff --git a/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c
index 4a6c1f3bcea1f..49289e5993dd7 100644
--- a/drivers/perf/arm_pmuv3.c
+++ b/drivers/perf/arm_pmuv3.c
@@ -813,7 +813,7 @@ static void armv8pmu_enable_user_access(struct arm_pmu *cpu_pmu)
 		write_pmuacr(mask);
 	} else {
 		/* Clear any unused counters to avoid leaking their contents */
-		for_each_andnot_bit(i, cpu_pmu->cntr_mask, cpuc->used_mask,
+		for_each_andnot_bit(i, cpuc->cntr_mask, cpuc->used_mask,
 				    ARMPMU_MAX_HWEVENTS) {
 			if (i == ARMV8_PMU_CYCLE_IDX)
 				write_pmccntr(0);
@@ -917,7 +917,7 @@ static irqreturn_t armv8pmu_handle_irq(struct arm_pmu *cpu_pmu)
 	 * to prevent skews in group events.
 	 */
 	armv8pmu_stop(cpu_pmu);
-	for_each_set_bit(idx, cpu_pmu->cntr_mask, ARMPMU_MAX_HWEVENTS) {
+	for_each_set_bit(idx, cpuc->cntr_mask, ARMPMU_MAX_HWEVENTS) {
 		struct perf_event *event = cpuc->events[idx];
 		struct hw_perf_event *hwc;
 
@@ -958,7 +958,7 @@ static int armv8pmu_get_single_idx(struct pmu_hw_events *cpuc,
 {
 	int idx;
 
-	for_each_set_bit(idx, cpu_pmu->cntr_mask, ARMV8_PMU_MAX_GENERAL_COUNTERS) {
+	for_each_set_bit(idx, cpuc->cntr_mask, ARMV8_PMU_MAX_GENERAL_COUNTERS) {
 		if (!test_and_set_bit(idx, cpuc->used_mask))
 			return idx;
 	}
@@ -974,7 +974,7 @@ static int armv8pmu_get_chain_idx(struct pmu_hw_events *cpuc,
 	 * Chaining requires two consecutive event counters, where
 	 * the lower idx must be even.
 	 */
-	for_each_set_bit(idx, cpu_pmu->cntr_mask, ARMV8_PMU_MAX_GENERAL_COUNTERS) {
+	for_each_set_bit(idx, cpuc->cntr_mask, ARMV8_PMU_MAX_GENERAL_COUNTERS) {
 		if (!(idx & 0x1))
 			continue;
 		if (!test_and_set_bit(idx, cpuc->used_mask)) {
@@ -1042,7 +1042,7 @@ static int armv8pmu_get_event_idx(struct pmu_hw_events *cpuc,
 	 */
 	if ((evtype == ARMV8_PMUV3_PERFCTR_INST_RETIRED) &&
 	    !armv8pmu_event_get_threshold(&event->attr) &&
-	    test_bit(ARMV8_PMU_INSTR_IDX, cpu_pmu->cntr_mask) &&
+	    test_bit(ARMV8_PMU_INSTR_IDX, cpuc->cntr_mask) &&
 	    !armv8pmu_event_want_user_access(event)) {
 		if (!test_and_set_bit(ARMV8_PMU_INSTR_IDX, cpuc->used_mask))
 			return ARMV8_PMU_INSTR_IDX;
@@ -1426,6 +1426,7 @@ static int armv8pmu_probe_pmu(struct arm_pmu *cpu_pmu)
 		.present = false,
 	};
 	int ret;
+	int cpu;
 
 	ret = smp_call_function_any(&cpu_pmu->supported_cpus,
 				    __armv8pmu_probe_pmu,
@@ -1441,6 +1442,13 @@ static int armv8pmu_probe_pmu(struct arm_pmu *cpu_pmu)
 		if (ret)
 			return ret;
 	}
+
+	for_each_possible_cpu(cpu) {
+		struct pmu_hw_events *cpuc = per_cpu_ptr(cpu_pmu->hw_events, cpu);
+
+		bitmap_copy(cpuc->cntr_mask, cpu_pmu->cntr_mask, ARMPMU_MAX_HWEVENTS);
+	}
+
 	return 0;
 }
 
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index 02d2c7f45b527..be1e345e99a77 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -62,6 +62,7 @@ struct pmu_hw_events {
 	 * an event. A 0 means that the counter can be used.
 	 */
 	DECLARE_BITMAP(used_mask, ARMPMU_MAX_HWEVENTS);
+	DECLARE_BITMAP(cntr_mask, ARMPMU_MAX_HWEVENTS);
 
 	/*
 	 * When using percpu IRQs, we need a percpu dev_id. Place it here as we
-- 
2.56.0.rc1.310.g51773c2048-goog