[PATCH v11 7/7] arm: pmu: Add PMU definitions for cores not initially online

Jeremy Linton
2016-12-02T18:56:01Z

ACPI CPUs aren't associated with a PMU until they have been put
online. This means that we potentially have to update a PMU
definition the first time a CPU is hot added to the machine.

Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
---
drivers/perf/arm_pmu.c | 38 ++++++++++++++++++++++++++++++++++++--
include/linux/perf/arm_pmu.h | 4 ++++
2 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index fa40294..4abb2fe 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -711,6 +711,30 @@ static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
return 0;
}

+static DEFINE_SPINLOCK(arm_pmu_resource_lock);
+
+static void arm_perf_associate_new_cpu(struct arm_pmu *lpmu, unsigned int cpu)
+{
+ struct platform_device *pdev = lpmu->plat_device;
+ struct resource *res;
+ struct pmu_hw_events *events;
+ int num_res;
+
+ spin_lock(&arm_pmu_resource_lock);
+ for (num_res = 0; num_res < pdev->num_resources; num_res++) {
+ if (!pdev->resource[num_res].flags)
+ break;
+ }
+ res = &pdev->resource[num_res];
+ arm_pmu_acpi_retrieve_irq(res, cpu);
+ events = per_cpu_ptr(lpmu->hw_events, cpu);
+ cpumask_set_cpu(cpu, &lpmu->supported_cpus);
+ if (lpmu->irq_affinity)
+ lpmu->irq_affinity[num_res] = cpu;
+ events->percpu_pmu = lpmu;
+ spin_unlock(&arm_pmu_resource_lock);
+}
+
/*
* PMU hardware loses all context when a CPU goes offline.
* When a CPU is hotplugged back in, since some hardware registers are
@@ -721,10 +745,18 @@ 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);

- if (!cpumask_test_cpu(cpu, &pmu->supported_cpus))
- return 0;
+ if (!cpumask_test_cpu(cpu, &pmu->supported_cpus)) {
+ unsigned int cpuid = read_specific_cpuid(cpu);
+
+ if (acpi_disabled)
+ return 0;
+ if (cpuid != pmu->id)
+ return 0;
+ arm_perf_associate_new_cpu(pmu, cpu);
+ }
if (pmu->reset)
pmu->reset(pmu);
+
return 0;
}

@@ -905,6 +937,8 @@ static int probe_plat_pmu(struct arm_pmu *pmu,
struct platform_device *pdev = pmu->plat_device;
int irq = platform_get_irq(pdev, 0);

+ pmu->id = pmuid;
+
if (irq >= 0 && !irq_is_percpu(irq)) {
pmu->irq_affinity = kcalloc(pdev->num_resources, sizeof(int),
GFP_KERNEL);
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index 42b5edb..f652cd1 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -112,6 +112,7 @@ struct arm_pmu {
struct mutex reserve_mutex;
u64 max_period;
bool secure_access; /* 32-bit ARM only */
+ unsigned int id;
#define ARMV8_PMUV3_MAX_COMMON_EVENTS 0x40
DECLARE_BITMAP(pmceid_bitmap, ARMV8_PMUV3_MAX_COMMON_EVENTS);
struct platform_device *plat_device;
@@ -168,8 +169,11 @@ int arm_pmu_device_probe(struct platform_device *pdev,
#ifdef CONFIG_ARM_PMU_ACPI
struct acpi_madt_generic_interrupt;
void arm_pmu_parse_acpi(int cpu, struct acpi_madt_generic_interrupt *gic);
+int arm_pmu_acpi_retrieve_irq(struct resource *pdev, int cpu);
#else
#define arm_pmu_parse_acpi(a, b) do { } while (0)
+#define arm_pmu_acpi_retrieve_irq(pdev, cpu) \
+ do { } while (0)
#endif /* CONFIG_ARM_PMU_ACPI */

#endif /* __ARM_PMU_H__ */
--
2.5.5