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authorMark Rutland <mark.rutland@arm.com>2017-03-10 10:46:14 +0000
committerWill Deacon <will.deacon@arm.com>2017-03-31 18:20:02 +0100
commit7ed98e0168bd23d8ea3294e95254cc5b4000c948 (patch)
tree7e8de90dca98d514bde6ec83674188f8cefca897
parent2681f0184276d7fc934b6866a5a267f5b3369f7d (diff)
drivers/perf: arm_pmu: manage interrupts per-cpu
When requesting or freeing interrupts, we use platform_get_irq() to find relevant irqs, backing this up with additional information in an optional irq_affinity table. This means that our irq request and free paths are tied to a platform_device, and our request path must jump through a number of hoops in order to determine the required affinity of each interrupt. Given that the affinity must be static, we can compute the affinity once up-front at probe time, simplifying the irq request and free paths. By recording interrupts in a per-cpu data structure, we simplify a few paths, and permit a subsequent rework of the request and free paths. Signed-off-by: Mark Rutland <mark.rutland@arm.com> [will: rename local nr_irqs variable to avoid conflict with global] Signed-off-by: Will Deacon <will.deacon@arm.com>
-rw-r--r--drivers/perf/arm_pmu.c314
-rw-r--r--include/linux/perf/arm_pmu.h3
2 files changed, 166 insertions, 151 deletions
diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index ad60e966f174..e984653b93aa 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -617,94 +617,76 @@ static void cpu_pmu_disable_percpu_irq(void *data)
static void cpu_pmu_free_irq(struct arm_pmu *cpu_pmu)
{
- int i, irq, irqs;
- struct platform_device *pmu_device = cpu_pmu->plat_device;
+ int cpu;
struct pmu_hw_events __percpu *hw_events = cpu_pmu->hw_events;
- irqs = min(pmu_device->num_resources, num_possible_cpus());
-
- irq = platform_get_irq(pmu_device, 0);
- if (irq > 0 && irq_is_percpu(irq)) {
- on_each_cpu_mask(&cpu_pmu->supported_cpus,
- cpu_pmu_disable_percpu_irq, &irq, 1);
- free_percpu_irq(irq, &hw_events->percpu_pmu);
- } else {
- for (i = 0; i < irqs; ++i) {
- int cpu = i;
-
- if (cpu_pmu->irq_affinity)
- cpu = cpu_pmu->irq_affinity[i];
-
- if (!cpumask_test_and_clear_cpu(cpu, &cpu_pmu->active_irqs))
- continue;
- irq = platform_get_irq(pmu_device, i);
- if (irq > 0)
- free_irq(irq, per_cpu_ptr(&hw_events->percpu_pmu, cpu));
+ for_each_cpu(cpu, &cpu_pmu->supported_cpus) {
+ int irq = per_cpu(hw_events->irq, cpu);
+ if (!irq)
+ continue;
+
+ if (irq_is_percpu(irq)) {
+ on_each_cpu_mask(&cpu_pmu->supported_cpus,
+ cpu_pmu_disable_percpu_irq, &irq, 1);
+ free_percpu_irq(irq, &hw_events->percpu_pmu);
+
+ break;
}
+
+ if (!cpumask_test_and_clear_cpu(cpu, &cpu_pmu->active_irqs))
+ continue;
+
+ free_irq(irq, per_cpu_ptr(&hw_events->percpu_pmu, cpu));
}
}
static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
{
- int i, err, irq, irqs;
- struct platform_device *pmu_device = cpu_pmu->plat_device;
+ int cpu, err;
struct pmu_hw_events __percpu *hw_events = cpu_pmu->hw_events;
- if (!pmu_device)
- return -ENODEV;
-
- irqs = min(pmu_device->num_resources, num_possible_cpus());
- if (irqs < 1) {
- pr_warn_once("perf/ARM: No irqs for PMU defined, sampling events not supported\n");
- return 0;
- }
-
- irq = platform_get_irq(pmu_device, 0);
- if (irq > 0 && irq_is_percpu(irq)) {
- err = request_percpu_irq(irq, handler, "arm-pmu",
- &hw_events->percpu_pmu);
- if (err) {
- pr_err("unable to request IRQ%d for ARM PMU counters\n",
- irq);
- return err;
- }
-
- on_each_cpu_mask(&cpu_pmu->supported_cpus,
- cpu_pmu_enable_percpu_irq, &irq, 1);
- } else {
- for (i = 0; i < irqs; ++i) {
- int cpu = i;
-
- err = 0;
- irq = platform_get_irq(pmu_device, i);
- if (irq < 0)
- continue;
-
- if (cpu_pmu->irq_affinity)
- cpu = cpu_pmu->irq_affinity[i];
-
- /*
- * If we have a single PMU interrupt that we can't shift,
- * assume that we're running on a uniprocessor machine and
- * continue. Otherwise, continue without this interrupt.
- */
- if (irq_set_affinity(irq, cpumask_of(cpu)) && irqs > 1) {
- pr_warn("unable to set irq affinity (irq=%d, cpu=%u)\n",
- irq, cpu);
- continue;
- }
+ for_each_cpu(cpu, &cpu_pmu->supported_cpus) {
+ int irq = per_cpu(hw_events->irq, cpu);
+ if (!irq)
+ continue;
- err = request_irq(irq, handler,
- IRQF_NOBALANCING | IRQF_NO_THREAD, "arm-pmu",
- per_cpu_ptr(&hw_events->percpu_pmu, cpu));
+ if (irq_is_percpu(irq)) {
+ err = request_percpu_irq(irq, handler, "arm-pmu",
+ &hw_events->percpu_pmu);
if (err) {
pr_err("unable to request IRQ%d for ARM PMU counters\n",
irq);
return err;
}
- cpumask_set_cpu(cpu, &cpu_pmu->active_irqs);
+ on_each_cpu_mask(&cpu_pmu->supported_cpus,
+ cpu_pmu_enable_percpu_irq, &irq, 1);
+
+ break;
}
+
+ /*
+ * If we have a single PMU interrupt that we can't shift,
+ * assume that we're running on a uniprocessor machine and
+ * continue. Otherwise, continue without this interrupt.
+ */
+ if (irq_set_affinity(irq, cpumask_of(cpu)) &&
+ num_possible_cpus() > 1) {
+ pr_warn("unable to set irq affinity (irq=%d, cpu=%u)\n",
+ irq, cpu);
+ continue;
+ }
+
+ err = request_irq(irq, handler,
+ IRQF_NOBALANCING | IRQF_NO_THREAD, "arm-pmu",
+ per_cpu_ptr(&hw_events->percpu_pmu, cpu));
+ if (err) {
+ pr_err("unable to request IRQ%d for ARM PMU counters\n",
+ irq);
+ return err;
+ }
+
+ cpumask_set_cpu(cpu, &cpu_pmu->active_irqs);
}
return 0;
@@ -846,10 +828,6 @@ static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
on_each_cpu_mask(&cpu_pmu->supported_cpus, cpu_pmu->reset,
cpu_pmu, 1);
- /* If no interrupts available, set the corresponding capability flag */
- if (!platform_get_irq(cpu_pmu->plat_device, 0))
- cpu_pmu->pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
-
/*
* This is a CPU PMU potentially in a heterogeneous configuration (e.g.
* big.LITTLE). This is not an uncore PMU, and we have taken ctx
@@ -897,98 +875,133 @@ static int probe_current_pmu(struct arm_pmu *pmu,
return ret;
}
-static int of_pmu_irq_cfg(struct arm_pmu *pmu)
+static int pmu_parse_percpu_irq(struct arm_pmu *pmu, int irq)
{
- int *irqs, i = 0;
- bool using_spi = false;
- struct platform_device *pdev = pmu->plat_device;
+ int cpu, ret;
+ struct pmu_hw_events __percpu *hw_events = pmu->hw_events;
- irqs = kcalloc(pdev->num_resources, sizeof(*irqs), GFP_KERNEL);
- if (!irqs)
- return -ENOMEM;
+ ret = irq_get_percpu_devid_partition(irq, &pmu->supported_cpus);
+ if (ret)
+ return ret;
- do {
- struct device_node *dn;
- int cpu, irq;
+ for_each_cpu(cpu, &pmu->supported_cpus)
+ per_cpu(hw_events->irq, cpu) = irq;
- /* See if we have an affinity entry */
- dn = of_parse_phandle(pdev->dev.of_node, "interrupt-affinity", i);
- if (!dn)
- break;
+ return 0;
+}
- /* Check the IRQ type and prohibit a mix of PPIs and SPIs */
- irq = platform_get_irq(pdev, i);
- if (irq > 0) {
- bool spi = !irq_is_percpu(irq);
-
- if (i > 0 && spi != using_spi) {
- pr_err("PPI/SPI IRQ type mismatch for %s!\n",
- dn->name);
- of_node_put(dn);
- kfree(irqs);
- return -EINVAL;
- }
+static bool pmu_has_irq_affinity(struct device_node *node)
+{
+ return !!of_find_property(node, "interrupt-affinity", NULL);
+}
- using_spi = spi;
- }
+static int pmu_parse_irq_affinity(struct device_node *node, int i)
+{
+ struct device_node *dn;
+ int cpu;
- /* Now look up the logical CPU number */
- for_each_possible_cpu(cpu) {
- struct device_node *cpu_dn;
+ /*
+ * If we don't have an interrupt-affinity property, we guess irq
+ * affinity matches our logical CPU order, as we used to assume.
+ * This is fragile, so we'll warn in pmu_parse_irqs().
+ */
+ if (!pmu_has_irq_affinity(node))
+ return i;
- cpu_dn = of_cpu_device_node_get(cpu);
- of_node_put(cpu_dn);
+ dn = of_parse_phandle(node, "interrupt-affinity", i);
+ if (!dn) {
+ pr_warn("failed to parse interrupt-affinity[%d] for %s\n",
+ i, node->name);
+ return -EINVAL;
+ }
- if (dn == cpu_dn)
- break;
- }
+ /* Now look up the logical CPU number */
+ for_each_possible_cpu(cpu) {
+ struct device_node *cpu_dn;
+
+ cpu_dn = of_cpu_device_node_get(cpu);
+ of_node_put(cpu_dn);
- if (cpu >= nr_cpu_ids) {
- pr_warn("Failed to find logical CPU for %s\n",
- dn->name);
- of_node_put(dn);
- cpumask_setall(&pmu->supported_cpus);
+ if (dn == cpu_dn)
break;
- }
- of_node_put(dn);
+ }
- /* For SPIs, we need to track the affinity per IRQ */
- if (using_spi) {
- if (i >= pdev->num_resources)
- break;
+ if (cpu >= nr_cpu_ids) {
+ pr_warn("failed to find logical CPU for %s\n", dn->name);
+ }
- irqs[i] = cpu;
- }
+ of_node_put(dn);
- /* Keep track of the CPUs containing this PMU type */
- cpumask_set_cpu(cpu, &pmu->supported_cpus);
- i++;
- } while (1);
+ return cpu;
+}
+
+static int pmu_parse_irqs(struct arm_pmu *pmu)
+{
+ int i = 0, irqs;
+ struct platform_device *pdev = pmu->plat_device;
+ struct pmu_hw_events __percpu *hw_events = pmu->hw_events;
+
+ irqs = platform_irq_count(pdev);
+ if (irqs < 0) {
+ pr_err("unable to count PMU IRQs\n");
+ return irqs;
+ }
+
+ /*
+ * In this case we have no idea which CPUs are covered by the PMU.
+ * To match our prior behaviour, we assume all CPUs in this case.
+ */
+ if (irqs == 0) {
+ pr_warn("no irqs for PMU, sampling events not supported\n");
+ pmu->pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
+ cpumask_setall(&pmu->supported_cpus);
+ return 0;
+ }
- /* If we didn't manage to parse anything, try the interrupt affinity */
- if (cpumask_weight(&pmu->supported_cpus) == 0) {
+ if (irqs == 1) {
int irq = platform_get_irq(pdev, 0);
+ if (irq && irq_is_percpu(irq))
+ return pmu_parse_percpu_irq(pmu, irq);
+ }
- if (irq > 0 && irq_is_percpu(irq)) {
- /* If using PPIs, check the affinity of the partition */
- int ret;
+ if (!pmu_has_irq_affinity(pdev->dev.of_node)) {
+ pr_warn("no interrupt-affinity property for %s, guessing.\n",
+ of_node_full_name(pdev->dev.of_node));
+ }
- ret = irq_get_percpu_devid_partition(irq, &pmu->supported_cpus);
- if (ret) {
- kfree(irqs);
- return ret;
- }
- } else {
- /* Otherwise default to all CPUs */
- cpumask_setall(&pmu->supported_cpus);
+ /*
+ * Some platforms have all PMU IRQs OR'd into a single IRQ, with a
+ * special platdata function that attempts to demux them.
+ */
+ if (dev_get_platdata(&pdev->dev))
+ cpumask_setall(&pmu->supported_cpus);
+
+ for (i = 0; i < irqs; i++) {
+ int cpu, irq;
+
+ irq = platform_get_irq(pdev, i);
+ if (WARN_ON(irq <= 0))
+ continue;
+
+ if (irq_is_percpu(irq)) {
+ pr_warn("multiple PPIs or mismatched SPI/PPI detected\n");
+ return -EINVAL;
}
- }
- /* If we matched up the IRQ affinities, use them to route the SPIs */
- if (using_spi && i == pdev->num_resources)
- pmu->irq_affinity = irqs;
- else
- kfree(irqs);
+ cpu = pmu_parse_irq_affinity(pdev->dev.of_node, i);
+ if (cpu < 0)
+ return cpu;
+ if (cpu >= nr_cpu_ids)
+ continue;
+
+ if (per_cpu(hw_events->irq, cpu)) {
+ pr_warn("multiple PMU IRQs for the same CPU detected\n");
+ return -EINVAL;
+ }
+
+ per_cpu(hw_events->irq, cpu) = irq;
+ cpumask_set_cpu(cpu, &pmu->supported_cpus);
+ }
return 0;
}
@@ -1050,6 +1063,10 @@ int arm_pmu_device_probe(struct platform_device *pdev,
pmu->plat_device = pdev;
+ ret = pmu_parse_irqs(pmu);
+ if (ret)
+ goto out_free;
+
if (node && (of_id = of_match_node(of_table, pdev->dev.of_node))) {
init_fn = of_id->data;
@@ -1062,9 +1079,7 @@ int arm_pmu_device_probe(struct platform_device *pdev,
pmu->secure_access = false;
}
- ret = of_pmu_irq_cfg(pmu);
- if (!ret)
- ret = init_fn(pmu);
+ ret = init_fn(pmu);
} else if (probe_table) {
cpumask_setall(&pmu->supported_cpus);
ret = probe_current_pmu(pmu, probe_table);
@@ -1097,7 +1112,6 @@ out_destroy:
out_free:
pr_info("%s: failed to register PMU devices!\n",
of_node_full_name(node));
- kfree(pmu->irq_affinity);
armpmu_free(pmu);
return ret;
}
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index 8462da266089..05a3eb447fc8 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -75,6 +75,8 @@ struct pmu_hw_events {
* already have to allocate this struct per cpu.
*/
struct arm_pmu *percpu_pmu;
+
+ int irq;
};
enum armpmu_attr_groups {
@@ -88,7 +90,6 @@ struct arm_pmu {
struct pmu pmu;
cpumask_t active_irqs;
cpumask_t supported_cpus;
- int *irq_affinity;
char *name;
irqreturn_t (*handle_irq)(int irq_num, void *dev);
void (*enable)(struct perf_event *event);

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