diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/include/asm/pmu.h | 10 | ||||
| -rw-r--r-- | arch/arm/kernel/perf_event.c | 11 | ||||
| -rw-r--r-- | arch/arm/kernel/perf_event_cpu.c | 94 | ||||
| -rw-r--r-- | arch/arm/mach-ux500/cpu-db8500.c | 29 |
4 files changed, 107 insertions, 37 deletions
diff --git a/arch/arm/include/asm/pmu.h b/arch/arm/include/asm/pmu.h index 0b648c541293..36472c3cc283 100644 --- a/arch/arm/include/asm/pmu.h +++ b/arch/arm/include/asm/pmu.h @@ -81,6 +81,12 @@ struct pmu_hw_events { raw_spinlock_t pmu_lock; }; +struct arm_pmu_work { + struct irq_work work; + struct arm_pmu *arm_pmu; + atomic_t ret; +}; + struct arm_pmu { struct pmu pmu; cpumask_t active_irqs; @@ -101,6 +107,7 @@ struct arm_pmu { void (*reset)(void *); int (*request_irq)(struct arm_pmu *, irq_handler_t handler); void (*free_irq)(struct arm_pmu *); + irqreturn_t (*handle_irq_none)(struct arm_pmu *); int (*map_event)(struct perf_event *event); int num_events; atomic_t active_events; @@ -108,6 +115,9 @@ struct arm_pmu { u64 max_period; struct platform_device *plat_device; struct pmu_hw_events *(*get_hw_events)(void); + int single_irq; + struct arm_pmu_work __percpu *work; + atomic_t remaining_work; }; #define to_arm_pmu(p) (container_of(p, struct arm_pmu, pmu)) diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c index b50a770f8c99..48eaae5427f9 100644 --- a/arch/arm/kernel/perf_event.c +++ b/arch/arm/kernel/perf_event.c @@ -306,22 +306,17 @@ validate_group(struct perf_event *event) static irqreturn_t armpmu_dispatch_irq(int irq, void *dev) { struct arm_pmu *armpmu; - struct platform_device *plat_device; - struct arm_pmu_platdata *plat; int ret; u64 start_clock, finish_clock; if (irq_is_percpu(irq)) dev = *(void **)dev; armpmu = dev; - plat_device = armpmu->plat_device; - plat = dev_get_platdata(&plat_device->dev); start_clock = sched_clock(); - if (plat && plat->handle_irq) - ret = plat->handle_irq(irq, dev, armpmu->handle_irq); - else - ret = armpmu->handle_irq(irq, dev); + ret = armpmu->handle_irq(irq, dev); + if (unlikely(ret == IRQ_NONE) && armpmu->handle_irq_none) + ret = armpmu->handle_irq_none(dev); finish_clock = sched_clock(); perf_sample_event_took(finish_clock - start_clock); diff --git a/arch/arm/kernel/perf_event_cpu.c b/arch/arm/kernel/perf_event_cpu.c index eb2c4d55666b..e7153dc3b489 100644 --- a/arch/arm/kernel/perf_event_cpu.c +++ b/arch/arm/kernel/perf_event_cpu.c @@ -88,6 +88,75 @@ static void cpu_pmu_disable_percpu_irq(void *data) disable_percpu_irq(irq); } +/* + * Workaround logic that is distributed to all cores if the PMU has only + * a single IRQ and the CPU receiving that IRQ cannot handle it. Its + * job is to try to service the interrupt on the current CPU. It will + * also enable the IRQ again if all the other CPUs have already tried to + * service it. + */ +static void cpu_pmu_do_percpu_work(struct irq_work *w) +{ + struct arm_pmu_work *work = container_of(w, struct arm_pmu_work, work); + struct arm_pmu *cpu_pmu = work->arm_pmu; + + atomic_set(&work->ret, + cpu_pmu->handle_irq(cpu_pmu->single_irq, cpu_pmu)); + + if (atomic_dec_and_test(&cpu_pmu->remaining_work)) + enable_irq(cpu_pmu->single_irq); +} + +/* + * This callback, which is enabled only on SMP platforms that are + * running with a single IRQ, is called when the PMU handler running in + * the current CPU cannot service the interrupt. + * + * It will disable the interrupt and distribute irqwork to all other + * processors in the system. Hopefully one of them will clear the + * interrupt... + */ +static irqreturn_t cpu_pmu_handle_irq_none(struct arm_pmu *cpu_pmu) +{ + int num_online = num_online_cpus(); + irqreturn_t ret = IRQ_NONE; + int cpu, cret; + + if (num_online <= 1) + return IRQ_NONE; + + disable_irq_nosync(cpu_pmu->single_irq); + atomic_add(num_online, &cpu_pmu->remaining_work); + smp_mb__after_atomic(); + + for_each_online_cpu(cpu) { + struct arm_pmu_work *work = per_cpu_ptr(cpu_pmu->work, cpu); + + if (cpu == smp_processor_id()) + continue; + + /* + * We can be extremely relaxed about memory ordering + * here. All we are doing is gathering information + * about the past to help us give a return value that + * will keep the spurious interrupt detector both happy + * *and* functional. We are not shared so we can + * tolerate the occasional spurious IRQ_HANDLED. + */ + cret = atomic_read(&work->ret); + if (cret != IRQ_NONE) + ret = cret; + + if (!irq_work_queue_on(&work->work, cpu)) + atomic_dec(&cpu_pmu->remaining_work); + } + + if (atomic_dec_and_test(&cpu_pmu->remaining_work)) + enable_irq(cpu_pmu->single_irq); + + return ret; +} + static void cpu_pmu_free_irq(struct arm_pmu *cpu_pmu) { int i, irq, irqs; @@ -107,6 +176,9 @@ static void cpu_pmu_free_irq(struct arm_pmu *cpu_pmu) if (irq >= 0) free_irq(irq, cpu_pmu); } + + cpu_pmu->handle_irq_none = cpu_pmu_handle_irq_none; + free_percpu(cpu_pmu->work); } } @@ -162,6 +234,28 @@ static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler) cpumask_set_cpu(i, &cpu_pmu->active_irqs); } + + /* + * If we are running SMP and have only one interrupt source + * then get ready to share that single irq among the cores. + */ + if (nr_cpu_ids > 1 && irqs == 1) { + cpu_pmu->single_irq = platform_get_irq(pmu_device, 0); + cpu_pmu->work = alloc_percpu(struct arm_pmu_work); + if (!cpu_pmu->work) { + pr_err("no memory for shared IRQ workaround\n"); + return -ENOMEM; + } + + for_each_possible_cpu(i) { + struct arm_pmu_work *w = + per_cpu_ptr(cpu_pmu->work, i); + init_irq_work(&w->work, cpu_pmu_do_percpu_work); + w->arm_pmu = cpu_pmu; + } + + cpu_pmu->handle_irq_none = cpu_pmu_handle_irq_none; + } } return 0; diff --git a/arch/arm/mach-ux500/cpu-db8500.c b/arch/arm/mach-ux500/cpu-db8500.c index 6f63954c8bde..917774999c5c 100644 --- a/arch/arm/mach-ux500/cpu-db8500.c +++ b/arch/arm/mach-ux500/cpu-db8500.c @@ -12,8 +12,6 @@ #include <linux/init.h> #include <linux/device.h> #include <linux/amba/bus.h> -#include <linux/interrupt.h> -#include <linux/irq.h> #include <linux/platform_device.h> #include <linux/io.h> #include <linux/mfd/abx500/ab8500.h> @@ -23,7 +21,6 @@ #include <linux/regulator/machine.h> #include <linux/random.h> -#include <asm/pmu.h> #include <asm/mach/map.h> #include "setup.h" @@ -99,30 +96,6 @@ static void __init u8500_map_io(void) iotable_init(u8500_io_desc, ARRAY_SIZE(u8500_io_desc)); } -/* - * The PMU IRQ lines of two cores are wired together into a single interrupt. - * Bounce the interrupt to the other core if it's not ours. - */ -static irqreturn_t db8500_pmu_handler(int irq, void *dev, irq_handler_t handler) -{ - irqreturn_t ret = handler(irq, dev); - int other = !smp_processor_id(); - - if (ret == IRQ_NONE && cpu_online(other)) - irq_set_affinity(irq, cpumask_of(other)); - - /* - * We should be able to get away with the amount of IRQ_NONEs we give, - * while still having the spurious IRQ detection code kick in if the - * interrupt really starts hitting spuriously. - */ - return ret; -} - -static struct arm_pmu_platdata db8500_pmu_platdata = { - .handle_irq = db8500_pmu_handler, -}; - static const char *db8500_read_soc_id(void) { void __iomem *uid = __io_address(U8500_BB_UID_BASE); @@ -143,8 +116,6 @@ static struct device * __init db8500_soc_device_init(void) } static struct of_dev_auxdata u8500_auxdata_lookup[] __initdata = { - /* Requires call-back bindings. */ - OF_DEV_AUXDATA("arm,cortex-a9-pmu", 0, "arm-pmu", &db8500_pmu_platdata), /* Requires DMA bindings. */ OF_DEV_AUXDATA("stericsson,ux500-msp-i2s", 0x80123000, "ux500-msp-i2s.0", &msp0_platform_data), |