From 8d1a0ae724ad74ef7946a45e3b2d3e01f39df02b Mon Sep 17 00:00:00 2001 From: Martin Fuzzey Date: Wed, 13 Jan 2016 23:36:26 -0500 Subject: ARM: perf: Set ARMv7 SDER SUNIDEN bit ARMv7 counters other than the CPU cycle counter only work if the Secure Debug Enable Register (SDER) SUNIDEN bit is set. Since access to the SDER is only possible in secure state, it will only be done if the device tree property "secure-reg-access" is set. Without this: Performance counter stats for 'sleep 1': 14606094 cycles # 0.000 GHz 0 instructions # 0.00 insns per cycle After applying: Performance counter stats for 'sleep 1': 5843809 cycles 2566484 instructions # 0.44 insns per cycle 1.020144000 seconds time elapsed Some platforms (eg i.MX53) may also need additional platform specific setup. Acked-by: Rob Herring Signed-off-by: Martin Fuzzey Signed-off-by: Pooya Keshavarzi Signed-off-by: George G. Davis [will: add warning if property is found on arm64] Signed-off-by: Will Deacon --- include/linux/perf/arm_pmu.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h index 83b5e34c6580..2d5eaaa90078 100644 --- a/include/linux/perf/arm_pmu.h +++ b/include/linux/perf/arm_pmu.h @@ -104,6 +104,7 @@ struct arm_pmu { atomic_t active_events; struct mutex reserve_mutex; u64 max_period; + bool secure_access; /* 32-bit ARM only */ struct platform_device *plat_device; struct pmu_hw_events __percpu *hw_events; struct notifier_block hotplug_nb; -- cgit v1.2.3 From da4e4f18afe0f3729d68f3785c5802f786d36e34 Mon Sep 17 00:00:00 2001 From: Lorenzo Pieralisi Date: Tue, 23 Feb 2016 18:22:39 +0000 Subject: drivers/perf: arm_pmu: implement CPU_PM notifier When a CPU is suspended (either through suspend-to-RAM or CPUidle), its PMU registers content can be lost, which means that counters registers values that were initialized on power down entry have to be reprogrammed on power-up to make sure the counters set-up is preserved (ie on power-up registers take the reset values on Cold or Warm reset, which can be architecturally UNKNOWN). To guarantee seamless profiling conditions across a core power down this patch adds a CPU PM notifier to ARM pmus, that upon CPU PM entry/exit from low-power states saves/restores the pmu registers set-up (by using the ARM perf API), so that the power-down/up cycle does not affect the perf behaviour (apart from a black-out period between power-up/down CPU PM notifications that is unavoidable). Cc: Will Deacon Cc: Sudeep Holla Cc: Daniel Lezcano Cc: Mathieu Poirier Cc: Mark Rutland Acked-by: Ashwin Chaugule Acked-by: Kevin Hilman Signed-off-by: Lorenzo Pieralisi Signed-off-by: Will Deacon --- drivers/perf/arm_pmu.c | 95 ++++++++++++++++++++++++++++++++++++++++++++ include/linux/perf/arm_pmu.h | 1 + 2 files changed, 96 insertions(+) (limited to 'include/linux') diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c index ca63a452393a..11bacc7220a1 100644 --- a/drivers/perf/arm_pmu.c +++ b/drivers/perf/arm_pmu.c @@ -13,6 +13,7 @@ #include #include +#include #include #include #include @@ -710,6 +711,93 @@ static int cpu_pmu_notify(struct notifier_block *b, unsigned long action, return NOTIFY_OK; } +#ifdef CONFIG_CPU_PM +static void cpu_pm_pmu_setup(struct arm_pmu *armpmu, unsigned long cmd) +{ + struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events); + struct perf_event *event; + int idx; + + for (idx = 0; idx < armpmu->num_events; idx++) { + /* + * If the counter is not used skip it, there is no + * need of stopping/restarting it. + */ + if (!test_bit(idx, hw_events->used_mask)) + continue; + + event = hw_events->events[idx]; + + switch (cmd) { + case CPU_PM_ENTER: + /* + * Stop and update the counter + */ + armpmu_stop(event, PERF_EF_UPDATE); + break; + case CPU_PM_EXIT: + case CPU_PM_ENTER_FAILED: + /* Restore and enable the counter */ + armpmu_start(event, PERF_EF_RELOAD); + break; + default: + break; + } + } +} + +static int cpu_pm_pmu_notify(struct notifier_block *b, unsigned long cmd, + void *v) +{ + struct arm_pmu *armpmu = container_of(b, struct arm_pmu, cpu_pm_nb); + struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events); + int enabled = bitmap_weight(hw_events->used_mask, armpmu->num_events); + + if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus)) + return NOTIFY_DONE; + + /* + * Always reset the PMU registers on power-up even if + * there are no events running. + */ + if (cmd == CPU_PM_EXIT && armpmu->reset) + armpmu->reset(armpmu); + + if (!enabled) + return NOTIFY_OK; + + switch (cmd) { + case CPU_PM_ENTER: + armpmu->stop(armpmu); + cpu_pm_pmu_setup(armpmu, cmd); + break; + case CPU_PM_EXIT: + cpu_pm_pmu_setup(armpmu, cmd); + case CPU_PM_ENTER_FAILED: + armpmu->start(armpmu); + break; + default: + return NOTIFY_DONE; + } + + return NOTIFY_OK; +} + +static int cpu_pm_pmu_register(struct arm_pmu *cpu_pmu) +{ + cpu_pmu->cpu_pm_nb.notifier_call = cpu_pm_pmu_notify; + return cpu_pm_register_notifier(&cpu_pmu->cpu_pm_nb); +} + +static void cpu_pm_pmu_unregister(struct arm_pmu *cpu_pmu) +{ + cpu_pm_unregister_notifier(&cpu_pmu->cpu_pm_nb); +} +#else +static inline int cpu_pm_pmu_register(struct arm_pmu *cpu_pmu) { return 0; } +static inline void cpu_pm_pmu_unregister(struct arm_pmu *cpu_pmu) { } +#endif + static int cpu_pmu_init(struct arm_pmu *cpu_pmu) { int err; @@ -725,6 +813,10 @@ static int cpu_pmu_init(struct arm_pmu *cpu_pmu) if (err) goto out_hw_events; + 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); @@ -746,6 +838,8 @@ static int cpu_pmu_init(struct arm_pmu *cpu_pmu) return 0; +out_unregister: + unregister_cpu_notifier(&cpu_pmu->hotplug_nb); out_hw_events: free_percpu(cpu_hw_events); return err; @@ -753,6 +847,7 @@ out_hw_events: static void cpu_pmu_destroy(struct arm_pmu *cpu_pmu) { + cpu_pm_pmu_unregister(cpu_pmu); unregister_cpu_notifier(&cpu_pmu->hotplug_nb); free_percpu(cpu_pmu->hw_events); } diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h index 2d5eaaa90078..4196c90a3c88 100644 --- a/include/linux/perf/arm_pmu.h +++ b/include/linux/perf/arm_pmu.h @@ -108,6 +108,7 @@ struct arm_pmu { struct platform_device *plat_device; struct pmu_hw_events __percpu *hw_events; struct notifier_block hotplug_nb; + struct notifier_block cpu_pm_nb; }; #define to_arm_pmu(p) (container_of(p, struct arm_pmu, pmu)) -- cgit v1.2.3