drivers/perf: arm_pmu: rework per-cpu allocation

For historical reasons, we allocate per-cpu data associated with a PMU
rather late, in cpu_pmu_init, after we've parsed whatever hardware
information we were provided with.

In order to allow use to store some per-cpu data early in the probe
path, we need to allocate (and initialise) the per-cpu data earlier.
This patch reworks the way we allocate the pmu and associated per-cpu
data in order to make that possible.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
[will: make armpmu_{alloc,free} static
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 9612b84bc3e0084f072023f16fa97823d3602467..ad60e966f17494e6e95a66eea316717e54acbe9a 100644 (file)
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -828,29 +828,16 @@ static inline void cpu_pm_pmu_unregister(struct arm_pmu *cpu_pmu) { }
 static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
 {
        int err;
-       int cpu;
-       struct pmu_hw_events __percpu *cpu_hw_events;
-
-       cpu_hw_events = alloc_percpu(struct pmu_hw_events);
-       if (!cpu_hw_events)
-               return -ENOMEM;
 
        err = cpuhp_state_add_instance_nocalls(CPUHP_AP_PERF_ARM_STARTING,
                                               &cpu_pmu->node);
        if (err)
-               goto out_free;
+               goto out;
 
        err = cpu_pm_pmu_register(cpu_pmu);
        if (err)
                goto out_unregister;
 
-       for_each_possible_cpu(cpu) {
-               struct pmu_hw_events *events = per_cpu_ptr(cpu_hw_events, cpu);
-               raw_spin_lock_init(&events->pmu_lock);
-               events->percpu_pmu = cpu_pmu;
-       }
-
-       cpu_pmu->hw_events      = cpu_hw_events;
        cpu_pmu->request_irq    = cpu_pmu_request_irq;
        cpu_pmu->free_irq       = cpu_pmu_free_irq;
 
@@ -876,8 +863,7 @@ static int cpu_pmu_init(struct arm_pmu *cpu_pmu)
 out_unregister:
        cpuhp_state_remove_instance_nocalls(CPUHP_AP_PERF_ARM_STARTING,
                                            &cpu_pmu->node);
-out_free:
-       free_percpu(cpu_hw_events);
+out:
        return err;
 }
 
@@ -886,7 +872,6 @@ static void cpu_pmu_destroy(struct arm_pmu *cpu_pmu)
        cpu_pm_pmu_unregister(cpu_pmu);
        cpuhp_state_remove_instance_nocalls(CPUHP_AP_PERF_ARM_STARTING,
                                            &cpu_pmu->node);
-       free_percpu(cpu_pmu->hw_events);
 }
 
 /*
@@ -1008,6 +993,45 @@ static int of_pmu_irq_cfg(struct arm_pmu *pmu)
        return 0;
 }
 
+static struct arm_pmu *armpmu_alloc(void)
+{
+       struct arm_pmu *pmu;
+       int cpu;
+
+       pmu = kzalloc(sizeof(*pmu), GFP_KERNEL);
+       if (!pmu) {
+               pr_info("failed to allocate PMU device!\n");
+               goto out;
+       }
+
+       pmu->hw_events = alloc_percpu(struct pmu_hw_events);
+       if (!pmu->hw_events) {
+               pr_info("failed to allocate per-cpu PMU data.\n");
+               goto out_free_pmu;
+       }
+
+       for_each_possible_cpu(cpu) {
+               struct pmu_hw_events *events;
+
+               events = per_cpu_ptr(pmu->hw_events, cpu);
+               raw_spin_lock_init(&events->pmu_lock);
+               events->percpu_pmu = pmu;
+       }
+
+       return pmu;
+
+out_free_pmu:
+       kfree(pmu);
+out:
+       return NULL;
+}
+
+static void armpmu_free(struct arm_pmu *pmu)
+{
+       free_percpu(pmu->hw_events);
+       kfree(pmu);
+}
+
 int arm_pmu_device_probe(struct platform_device *pdev,
                         const struct of_device_id *of_table,
                         const struct pmu_probe_info *probe_table)
@@ -1018,11 +1042,9 @@ int arm_pmu_device_probe(struct platform_device *pdev,
        struct arm_pmu *pmu;
        int ret = -ENODEV;
 
-       pmu = kzalloc(sizeof(struct arm_pmu), GFP_KERNEL);
-       if (!pmu) {
-               pr_info("failed to allocate PMU device!\n");
+       pmu = armpmu_alloc();
+       if (!pmu)
                return -ENOMEM;
-       }
 
        armpmu_init(pmu);
 
@@ -1076,7 +1098,7 @@ out_free:
        pr_info("%s: failed to register PMU devices!\n",
                of_node_full_name(node));
        kfree(pmu->irq_affinity);
-       kfree(pmu);
+       armpmu_free(pmu);
        return ret;
 }