[PATCH v11 4/7] arm: arm64: pmu: Assign platform PMU CPU affinity

Jeremy Linton
2016-12-02T18:55:58Z

On systems with multiple PMU types the PMU to CPU affinity
needs to be detected and set. The CPU to interrupt affinity
should also be set.

Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
---
drivers/perf/arm_pmu.c | 43 +++++++++++++++++++++++++++++++++----------
1 file changed, 33 insertions(+), 10 deletions(-)

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index b37b572..00e98c5 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -11,6 +11,7 @@
*/
#define pr_fmt(fmt) "hw perfevents: " fmt

+#include <linux/acpi.h>
#include <linux/bitmap.h>
#include <linux/cpumask.h>
#include <linux/cpu_pm.h>
@@ -24,6 +25,7 @@
#include <linux/irq.h>
#include <linux/irqdesc.h>

+#include <asm/cpu.h>
#include <asm/cputype.h>
#include <asm/irq_regs.h>

@@ -889,25 +891,47 @@ static void cpu_pmu_destroy(struct arm_pmu *cpu_pmu)
}

/*
- * CPU PMU identification and probing.
+ * CPU PMU identification and probing. Its possible to have
+ * multiple CPU types in an ARM machine. Assure that we are
+ * picking the right PMU types based on the CPU in question
*/
-static int probe_current_pmu(struct arm_pmu *pmu,
- const struct pmu_probe_info *info)
+static int probe_plat_pmu(struct arm_pmu *pmu,
+ const struct pmu_probe_info *info,
+ unsigned int pmuid)
{
- int cpu = get_cpu();
- unsigned int cpuid = read_cpuid_id();
int ret = -ENODEV;
+ int cpu;
+ int aff_ctr = 0;
+ struct platform_device *pdev = pmu->plat_device;
+ int irq = platform_get_irq(pdev, 0);

- pr_info("probing PMU on CPU %d\n", cpu);
+ if (irq >= 0 && !irq_is_percpu(irq)) {
+ pmu->irq_affinity = kcalloc(pdev->num_resources, sizeof(int),
+ GFP_KERNEL);
+ if (!pmu->irq_affinity)
+ return -ENOMEM;
+ }
+
+ for_each_possible_cpu(cpu) {
+ unsigned int cpuid = read_specific_cpuid(cpu);
+
+ if (cpuid == pmuid) {
+ cpumask_set_cpu(cpu, &pmu->supported_cpus);
+ if (pmu->irq_affinity) {
+ pmu->irq_affinity[aff_ctr] = cpu;
+ aff_ctr++;
+ }
+ }
+ }

+ /* find the type of PMU given the CPU */
for (; info->init != NULL; info++) {
- if ((cpuid & info->mask) != info->cpuid)
+ if ((pmuid & info->mask) != info->cpuid)
continue;
ret = info->init(pmu);
break;
}

- put_cpu();
return ret;
}

@@ -1043,8 +1067,7 @@ int arm_pmu_device_probe(struct platform_device *pdev,
if (!ret)
ret = init_fn(pmu);
} else if (probe_table) {
- cpumask_setall(&pmu->supported_cpus);
- ret = probe_current_pmu(pmu, probe_table);
+ ret = probe_plat_pmu(pmu, probe_table, read_cpuid_id());
}

if (ret) {
--
2.5.5