arch/arm/kernel/perf_event_cpu.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License version 2 as
   4  * published by the Free Software Foundation.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9  * GNU General Public License for more details.
  10  *
  11  * You should have received a copy of the GNU General Public License
  12  * along with this program; if not, write to the Free Software
  13  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  14  *
  15  * Copyright (C) 2012 ARM Limited
  16  *
  17  * Author: Will Deacon <will.deacon@arm.com>
  18  */
  19 #define pr_fmt(fmt) "CPU PMU: " fmt
  20
  21 #include <linux/bitmap.h>
  22 #include <linux/export.h>
  23 #include <linux/kernel.h>
  24 #include <linux/of.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/slab.h>
  27 #include <linux/spinlock.h>
  28
  29 #include <asm/cputype.h>
  30 #include <asm/irq_regs.h>
  31 #include <asm/pmu.h>
  32
  33 /* Set at runtime when we know what CPU type we are. */
  34 static struct arm_pmu *cpu_pmu;
  35
  36 static DEFINE_PER_CPU(struct perf_event * [ARMPMU_MAX_HWEVENTS], hw_events);
  37 static DEFINE_PER_CPU(unsigned long [BITS_TO_LONGS(ARMPMU_MAX_HWEVENTS)], used_mask);
  38 static DEFINE_PER_CPU(struct pmu_hw_events, cpu_hw_events);
  39
  40 /*
  41  * Despite the names, these two functions are CPU-specific and are used
  42  * by the OProfile/perf code.
  43  */
  44 const char *perf_pmu_name(void)
  45 {
  46         if (!cpu_pmu)
  47                 return NULL;
  48
  49         return cpu_pmu->name;
  50 }
  51 EXPORT_SYMBOL_GPL(perf_pmu_name);
  52
  53 int perf_num_counters(void)
  54 {
  55         int max_events = 0;
  56
  57         if (cpu_pmu != NULL)
  58                 max_events = cpu_pmu->num_events;
  59
  60         return max_events;
  61 }
  62 EXPORT_SYMBOL_GPL(perf_num_counters);
  63
  64 /* Include the PMU-specific implementations. */
  65 #include "perf_event_xscale.c"
  66 #include "perf_event_v6.c"
  67 #include "perf_event_v7.c"
  68
  69 static struct pmu_hw_events *cpu_pmu_get_cpu_events(void)
  70 {
  71         return this_cpu_ptr(&cpu_hw_events);
  72 }
  73
  74 static void cpu_pmu_free_irq(struct arm_pmu *cpu_pmu)
  75 {
  76         int i, irq, irqs;
  77         struct platform_device *pmu_device = cpu_pmu->plat_device;
  78
  79         irqs = min(pmu_device->num_resources, num_possible_cpus());
  80
  81         for (i = 0; i < irqs; ++i) {
  82                 if (!cpumask_test_and_clear_cpu(i, &cpu_pmu->active_irqs))
  83                         continue;
  84                 irq = platform_get_irq(pmu_device, i);
  85                 if (irq >= 0)
  86                         free_irq(irq, cpu_pmu);
  87         }
  88 }
  89
  90 static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
  91 {
  92         int i, err, irq, irqs;
  93         struct platform_device *pmu_device = cpu_pmu->plat_device;
  94
  95         if (!pmu_device)
  96                 return -ENODEV;
  97
  98         irqs = min(pmu_device->num_resources, num_possible_cpus());
  99         if (irqs < 1) {
 100                 pr_err("no irqs for PMUs defined\n");
 101                 return -ENODEV;
 102         }
 103
 104         for (i = 0; i < irqs; ++i) {
 105                 err = 0;
 106                 irq = platform_get_irq(pmu_device, i);
 107                 if (irq < 0)
 108                         continue;
 109
 110                 /*
 111                  * If we have a single PMU interrupt that we can't shift,
 112                  * assume that we're running on a uniprocessor machine and
 113                  * continue. Otherwise, continue without this interrupt.
 114                  */
 115                 if (irq_set_affinity(irq, cpumask_of(i)) && irqs > 1) {
 116                         pr_warning("unable to set irq affinity (irq=%d, cpu=%u)\n",
 117                                     irq, i);
 118                         continue;
 119                 }
 120
 121                 err = request_irq(irq, handler,
 122                                   IRQF_NOBALANCING | IRQF_NO_THREAD, "arm-pmu",
 123                                   cpu_pmu);
 124                 if (err) {
 125                         pr_err("unable to request IRQ%d for ARM PMU counters\n",
 126                                 irq);
 127                         return err;
 128                 }
 129
 130                 cpumask_set_cpu(i, &cpu_pmu->active_irqs);
 131         }
 132
 133         return 0;
 134 }
 135
 136 static void cpu_pmu_init(struct arm_pmu *cpu_pmu)
 137 {
 138         int cpu;
 139         for_each_possible_cpu(cpu) {
 140                 struct pmu_hw_events *events = &per_cpu(cpu_hw_events, cpu);
 141                 events->events = per_cpu(hw_events, cpu);
 142                 events->used_mask = per_cpu(used_mask, cpu);
 143                 raw_spin_lock_init(&events->pmu_lock);
 144         }
 145
 146         cpu_pmu->get_hw_events  = cpu_pmu_get_cpu_events;
 147         cpu_pmu->request_irq    = cpu_pmu_request_irq;
 148         cpu_pmu->free_irq       = cpu_pmu_free_irq;
 149
 150         /* Ensure the PMU has sane values out of reset. */
 151         if (cpu_pmu->reset)
 152                 on_each_cpu(cpu_pmu->reset, cpu_pmu, 1);
 153 }
 154
 155 /*
 156  * PMU hardware loses all context when a CPU goes offline.
 157  * When a CPU is hotplugged back in, since some hardware registers are
 158  * UNKNOWN at reset, the PMU must be explicitly reset to avoid reading
 159  * junk values out of them.
 160  */
 161 static int cpu_pmu_notify(struct notifier_block *b, unsigned long action,
 162                           void *hcpu)
 163 {
 164         if ((action & ~CPU_TASKS_FROZEN) != CPU_STARTING)
 165                 return NOTIFY_DONE;
 166
 167         if (cpu_pmu && cpu_pmu->reset)
 168                 cpu_pmu->reset(cpu_pmu);
 169         else
 170                 return NOTIFY_DONE;
 171
 172         return NOTIFY_OK;
 173 }
 174
 175 static struct notifier_block cpu_pmu_hotplug_notifier = {
 176         .notifier_call = cpu_pmu_notify,
 177 };
 178
 179 /*
 180  * PMU platform driver and devicetree bindings.
 181  */
 182 static struct of_device_id cpu_pmu_of_device_ids[] = {
 183         {.compatible = "arm,cortex-a15-pmu",    .data = armv7_a15_pmu_init},
 184         {.compatible = "arm,cortex-a9-pmu",     .data = armv7_a9_pmu_init},
 185         {.compatible = "arm,cortex-a8-pmu",     .data = armv7_a8_pmu_init},
 186         {.compatible = "arm,cortex-a7-pmu",     .data = armv7_a7_pmu_init},
 187         {.compatible = "arm,cortex-a5-pmu",     .data = armv7_a5_pmu_init},
 188         {.compatible = "arm,arm11mpcore-pmu",   .data = armv6mpcore_pmu_init},
 189         {.compatible = "arm,arm1176-pmu",       .data = armv6pmu_init},
 190         {.compatible = "arm,arm1136-pmu",       .data = armv6pmu_init},
 191         {},
 192 };
 193
 194 static struct platform_device_id cpu_pmu_plat_device_ids[] = {
 195         {.name = "arm-pmu"},
 196         {},
 197 };
 198
 199 /*
 200  * CPU PMU identification and probing.
 201  */
 202 static int probe_current_pmu(struct arm_pmu *pmu)
 203 {
 204         int cpu = get_cpu();
 205         unsigned long implementor = read_cpuid_implementor();
 206         unsigned long part_number = read_cpuid_part_number();
 207         int ret = -ENODEV;
 208
 209         pr_info("probing PMU on CPU %d\n", cpu);
 210
 211         /* ARM Ltd CPUs. */
 212         if (implementor == ARM_CPU_IMP_ARM) {
 213                 switch (part_number) {
 214                 case ARM_CPU_PART_ARM1136:
 215                 case ARM_CPU_PART_ARM1156:
 216                 case ARM_CPU_PART_ARM1176:
 217                         ret = armv6pmu_init(pmu);
 218                         break;
 219                 case ARM_CPU_PART_ARM11MPCORE:
 220                         ret = armv6mpcore_pmu_init(pmu);
 221                         break;
 222                 case ARM_CPU_PART_CORTEX_A8:
 223                         ret = armv7_a8_pmu_init(pmu);
 224                         break;
 225                 case ARM_CPU_PART_CORTEX_A9:
 226                         ret = armv7_a9_pmu_init(pmu);
 227                         break;
 228                 case ARM_CPU_PART_CORTEX_A5:
 229                         ret = armv7_a5_pmu_init(pmu);
 230                         break;
 231                 case ARM_CPU_PART_CORTEX_A15:
 232                         ret = armv7_a15_pmu_init(pmu);
 233                         break;
 234                 case ARM_CPU_PART_CORTEX_A7:
 235                         ret = armv7_a7_pmu_init(pmu);
 236                         break;
 237                 }
 238         /* Intel CPUs [xscale]. */
 239         } else if (implementor == ARM_CPU_IMP_INTEL) {
 240                 switch (xscale_cpu_arch_version()) {
 241                 case ARM_CPU_XSCALE_ARCH_V1:
 242                         ret = xscale1pmu_init(pmu);
 243                         break;
 244                 case ARM_CPU_XSCALE_ARCH_V2:
 245                         ret = xscale2pmu_init(pmu);
 246                         break;
 247                 }
 248         }
 249
 250         put_cpu();
 251         return ret;
 252 }
 253
 254 static int cpu_pmu_device_probe(struct platform_device *pdev)
 255 {
 256         const struct of_device_id *of_id;
 257         const int (*init_fn)(struct arm_pmu *);
 258         struct device_node *node = pdev->dev.of_node;
 259         struct arm_pmu *pmu;
 260         int ret = -ENODEV;
 261
 262         if (cpu_pmu) {
 263                 pr_info("attempt to register multiple PMU devices!");
 264                 return -ENOSPC;
 265         }
 266
 267         pmu = kzalloc(sizeof(struct arm_pmu), GFP_KERNEL);
 268         if (!pmu) {
 269                 pr_info("failed to allocate PMU device!");
 270                 return -ENOMEM;
 271         }
 272
 273         if (node && (of_id = of_match_node(cpu_pmu_of_device_ids, pdev->dev.of_node))) {
 274                 init_fn = of_id->data;
 275                 ret = init_fn(pmu);
 276         } else {
 277                 ret = probe_current_pmu(pmu);
 278         }
 279
 280         if (ret) {
 281                 pr_info("failed to probe PMU!");
 282                 goto out_free;
 283         }
 284
 285         cpu_pmu = pmu;
 286         cpu_pmu->plat_device = pdev;
 287         cpu_pmu_init(cpu_pmu);
 288         ret = armpmu_register(cpu_pmu, PERF_TYPE_RAW);
 289
 290         if (!ret)
 291                 return 0;
 292
 293 out_free:
 294         pr_info("failed to register PMU devices!");
 295         kfree(pmu);
 296         return ret;
 297 }
 298
 299 static struct platform_driver cpu_pmu_driver = {
 300         .driver         = {
 301                 .name   = "arm-pmu",
 302                 .pm     = &armpmu_dev_pm_ops,
 303                 .of_match_table = cpu_pmu_of_device_ids,
 304         },
 305         .probe          = cpu_pmu_device_probe,
 306         .id_table       = cpu_pmu_plat_device_ids,
 307 };
 308
 309 static int __init register_pmu_driver(void)
 310 {
 311         int err;
 312
 313         err = register_cpu_notifier(&cpu_pmu_hotplug_notifier);
 314         if (err)
 315                 return err;
 316
 317         err = platform_driver_register(&cpu_pmu_driver);
 318         if (err)
 319                 unregister_cpu_notifier(&cpu_pmu_hotplug_notifier);
 320
 321         return err;
 322 }
 323 device_initcall(register_pmu_driver);