perf_event.c 19 KB

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  1. #undef DEBUG
  2. /*
  3. * ARM performance counter support.
  4. *
  5. * Copyright (C) 2009 picoChip Designs, Ltd., Jamie Iles
  6. * Copyright (C) 2010 ARM Ltd., Will Deacon <will.deacon@arm.com>
  7. *
  8. * This code is based on the sparc64 perf event code, which is in turn based
  9. * on the x86 code. Callchain code is based on the ARM OProfile backtrace
  10. * code.
  11. */
  12. #define pr_fmt(fmt) "hw perfevents: " fmt
  13. #include <linux/bitmap.h>
  14. #include <linux/interrupt.h>
  15. #include <linux/kernel.h>
  16. #include <linux/export.h>
  17. #include <linux/perf_event.h>
  18. #include <linux/platform_device.h>
  19. #include <linux/spinlock.h>
  20. #include <linux/uaccess.h>
  21. #include <asm/cputype.h>
  22. #include <asm/irq.h>
  23. #include <asm/irq_regs.h>
  24. #include <asm/pmu.h>
  25. #include <asm/stacktrace.h>
  26. /*
  27. * ARMv6 supports a maximum of 3 events, starting from index 0. If we add
  28. * another platform that supports more, we need to increase this to be the
  29. * largest of all platforms.
  30. *
  31. * ARMv7 supports up to 32 events:
  32. * cycle counter CCNT + 31 events counters CNT0..30.
  33. * Cortex-A8 has 1+4 counters, Cortex-A9 has 1+6 counters.
  34. */
  35. #define ARMPMU_MAX_HWEVENTS 32
  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. #define to_arm_pmu(p) (container_of(p, struct arm_pmu, pmu))
  40. /* Set at runtime when we know what CPU type we are. */
  41. static struct arm_pmu *cpu_pmu;
  42. enum arm_perf_pmu_ids
  43. armpmu_get_pmu_id(void)
  44. {
  45. int id = -ENODEV;
  46. if (cpu_pmu != NULL)
  47. id = cpu_pmu->id;
  48. return id;
  49. }
  50. EXPORT_SYMBOL_GPL(armpmu_get_pmu_id);
  51. int
  52. armpmu_get_max_events(void)
  53. {
  54. int max_events = 0;
  55. if (cpu_pmu != NULL)
  56. max_events = cpu_pmu->num_events;
  57. return max_events;
  58. }
  59. EXPORT_SYMBOL_GPL(armpmu_get_max_events);
  60. int perf_num_counters(void)
  61. {
  62. return armpmu_get_max_events();
  63. }
  64. EXPORT_SYMBOL_GPL(perf_num_counters);
  65. #define HW_OP_UNSUPPORTED 0xFFFF
  66. #define C(_x) \
  67. PERF_COUNT_HW_CACHE_##_x
  68. #define CACHE_OP_UNSUPPORTED 0xFFFF
  69. static int
  70. armpmu_map_cache_event(const unsigned (*cache_map)
  71. [PERF_COUNT_HW_CACHE_MAX]
  72. [PERF_COUNT_HW_CACHE_OP_MAX]
  73. [PERF_COUNT_HW_CACHE_RESULT_MAX],
  74. u64 config)
  75. {
  76. unsigned int cache_type, cache_op, cache_result, ret;
  77. cache_type = (config >> 0) & 0xff;
  78. if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
  79. return -EINVAL;
  80. cache_op = (config >> 8) & 0xff;
  81. if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
  82. return -EINVAL;
  83. cache_result = (config >> 16) & 0xff;
  84. if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
  85. return -EINVAL;
  86. ret = (int)(*cache_map)[cache_type][cache_op][cache_result];
  87. if (ret == CACHE_OP_UNSUPPORTED)
  88. return -ENOENT;
  89. return ret;
  90. }
  91. static int
  92. armpmu_map_event(const unsigned (*event_map)[PERF_COUNT_HW_MAX], u64 config)
  93. {
  94. int mapping = (*event_map)[config];
  95. return mapping == HW_OP_UNSUPPORTED ? -ENOENT : mapping;
  96. }
  97. static int
  98. armpmu_map_raw_event(u32 raw_event_mask, u64 config)
  99. {
  100. return (int)(config & raw_event_mask);
  101. }
  102. static int map_cpu_event(struct perf_event *event,
  103. const unsigned (*event_map)[PERF_COUNT_HW_MAX],
  104. const unsigned (*cache_map)
  105. [PERF_COUNT_HW_CACHE_MAX]
  106. [PERF_COUNT_HW_CACHE_OP_MAX]
  107. [PERF_COUNT_HW_CACHE_RESULT_MAX],
  108. u32 raw_event_mask)
  109. {
  110. u64 config = event->attr.config;
  111. switch (event->attr.type) {
  112. case PERF_TYPE_HARDWARE:
  113. return armpmu_map_event(event_map, config);
  114. case PERF_TYPE_HW_CACHE:
  115. return armpmu_map_cache_event(cache_map, config);
  116. case PERF_TYPE_RAW:
  117. return armpmu_map_raw_event(raw_event_mask, config);
  118. }
  119. return -ENOENT;
  120. }
  121. int
  122. armpmu_event_set_period(struct perf_event *event,
  123. struct hw_perf_event *hwc,
  124. int idx)
  125. {
  126. struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
  127. s64 left = local64_read(&hwc->period_left);
  128. s64 period = hwc->sample_period;
  129. int ret = 0;
  130. if (unlikely(left <= -period)) {
  131. left = period;
  132. local64_set(&hwc->period_left, left);
  133. hwc->last_period = period;
  134. ret = 1;
  135. }
  136. if (unlikely(left <= 0)) {
  137. left += period;
  138. local64_set(&hwc->period_left, left);
  139. hwc->last_period = period;
  140. ret = 1;
  141. }
  142. if (left > (s64)armpmu->max_period)
  143. left = armpmu->max_period;
  144. local64_set(&hwc->prev_count, (u64)-left);
  145. armpmu->write_counter(idx, (u64)(-left) & 0xffffffff);
  146. perf_event_update_userpage(event);
  147. return ret;
  148. }
  149. u64
  150. armpmu_event_update(struct perf_event *event,
  151. struct hw_perf_event *hwc,
  152. int idx, int overflow)
  153. {
  154. struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
  155. u64 delta, prev_raw_count, new_raw_count;
  156. again:
  157. prev_raw_count = local64_read(&hwc->prev_count);
  158. new_raw_count = armpmu->read_counter(idx);
  159. if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
  160. new_raw_count) != prev_raw_count)
  161. goto again;
  162. new_raw_count &= armpmu->max_period;
  163. prev_raw_count &= armpmu->max_period;
  164. if (overflow)
  165. delta = armpmu->max_period - prev_raw_count + new_raw_count + 1;
  166. else
  167. delta = new_raw_count - prev_raw_count;
  168. local64_add(delta, &event->count);
  169. local64_sub(delta, &hwc->period_left);
  170. return new_raw_count;
  171. }
  172. static void
  173. armpmu_read(struct perf_event *event)
  174. {
  175. struct hw_perf_event *hwc = &event->hw;
  176. /* Don't read disabled counters! */
  177. if (hwc->idx < 0)
  178. return;
  179. armpmu_event_update(event, hwc, hwc->idx, 0);
  180. }
  181. static void
  182. armpmu_stop(struct perf_event *event, int flags)
  183. {
  184. struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
  185. struct hw_perf_event *hwc = &event->hw;
  186. /*
  187. * ARM pmu always has to update the counter, so ignore
  188. * PERF_EF_UPDATE, see comments in armpmu_start().
  189. */
  190. if (!(hwc->state & PERF_HES_STOPPED)) {
  191. armpmu->disable(hwc, hwc->idx);
  192. barrier(); /* why? */
  193. armpmu_event_update(event, hwc, hwc->idx, 0);
  194. hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
  195. }
  196. }
  197. static void
  198. armpmu_start(struct perf_event *event, int flags)
  199. {
  200. struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
  201. struct hw_perf_event *hwc = &event->hw;
  202. /*
  203. * ARM pmu always has to reprogram the period, so ignore
  204. * PERF_EF_RELOAD, see the comment below.
  205. */
  206. if (flags & PERF_EF_RELOAD)
  207. WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
  208. hwc->state = 0;
  209. /*
  210. * Set the period again. Some counters can't be stopped, so when we
  211. * were stopped we simply disabled the IRQ source and the counter
  212. * may have been left counting. If we don't do this step then we may
  213. * get an interrupt too soon or *way* too late if the overflow has
  214. * happened since disabling.
  215. */
  216. armpmu_event_set_period(event, hwc, hwc->idx);
  217. armpmu->enable(hwc, hwc->idx);
  218. }
  219. static void
  220. armpmu_del(struct perf_event *event, int flags)
  221. {
  222. struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
  223. struct pmu_hw_events *hw_events = armpmu->get_hw_events();
  224. struct hw_perf_event *hwc = &event->hw;
  225. int idx = hwc->idx;
  226. WARN_ON(idx < 0);
  227. armpmu_stop(event, PERF_EF_UPDATE);
  228. hw_events->events[idx] = NULL;
  229. clear_bit(idx, hw_events->used_mask);
  230. perf_event_update_userpage(event);
  231. }
  232. static int
  233. armpmu_add(struct perf_event *event, int flags)
  234. {
  235. struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
  236. struct pmu_hw_events *hw_events = armpmu->get_hw_events();
  237. struct hw_perf_event *hwc = &event->hw;
  238. int idx;
  239. int err = 0;
  240. perf_pmu_disable(event->pmu);
  241. /* If we don't have a space for the counter then finish early. */
  242. idx = armpmu->get_event_idx(hw_events, hwc);
  243. if (idx < 0) {
  244. err = idx;
  245. goto out;
  246. }
  247. /*
  248. * If there is an event in the counter we are going to use then make
  249. * sure it is disabled.
  250. */
  251. event->hw.idx = idx;
  252. armpmu->disable(hwc, idx);
  253. hw_events->events[idx] = event;
  254. hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
  255. if (flags & PERF_EF_START)
  256. armpmu_start(event, PERF_EF_RELOAD);
  257. /* Propagate our changes to the userspace mapping. */
  258. perf_event_update_userpage(event);
  259. out:
  260. perf_pmu_enable(event->pmu);
  261. return err;
  262. }
  263. static int
  264. validate_event(struct pmu_hw_events *hw_events,
  265. struct perf_event *event)
  266. {
  267. struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
  268. struct hw_perf_event fake_event = event->hw;
  269. struct pmu *leader_pmu = event->group_leader->pmu;
  270. if (event->pmu != leader_pmu || event->state <= PERF_EVENT_STATE_OFF)
  271. return 1;
  272. return armpmu->get_event_idx(hw_events, &fake_event) >= 0;
  273. }
  274. static int
  275. validate_group(struct perf_event *event)
  276. {
  277. struct perf_event *sibling, *leader = event->group_leader;
  278. struct pmu_hw_events fake_pmu;
  279. DECLARE_BITMAP(fake_used_mask, ARMPMU_MAX_HWEVENTS);
  280. /*
  281. * Initialise the fake PMU. We only need to populate the
  282. * used_mask for the purposes of validation.
  283. */
  284. memset(fake_used_mask, 0, sizeof(fake_used_mask));
  285. fake_pmu.used_mask = fake_used_mask;
  286. if (!validate_event(&fake_pmu, leader))
  287. return -ENOSPC;
  288. list_for_each_entry(sibling, &leader->sibling_list, group_entry) {
  289. if (!validate_event(&fake_pmu, sibling))
  290. return -ENOSPC;
  291. }
  292. if (!validate_event(&fake_pmu, event))
  293. return -ENOSPC;
  294. return 0;
  295. }
  296. static irqreturn_t armpmu_platform_irq(int irq, void *dev)
  297. {
  298. struct arm_pmu *armpmu = (struct arm_pmu *) dev;
  299. struct platform_device *plat_device = armpmu->plat_device;
  300. struct arm_pmu_platdata *plat = dev_get_platdata(&plat_device->dev);
  301. return plat->handle_irq(irq, dev, armpmu->handle_irq);
  302. }
  303. static void
  304. armpmu_release_hardware(struct arm_pmu *armpmu)
  305. {
  306. int i, irq, irqs;
  307. struct platform_device *pmu_device = armpmu->plat_device;
  308. struct arm_pmu_platdata *plat =
  309. dev_get_platdata(&pmu_device->dev);
  310. irqs = min(pmu_device->num_resources, num_possible_cpus());
  311. for (i = 0; i < irqs; ++i) {
  312. if (!cpumask_test_and_clear_cpu(i, &armpmu->active_irqs))
  313. continue;
  314. irq = platform_get_irq(pmu_device, i);
  315. if (irq >= 0) {
  316. if (plat && plat->disable_irq)
  317. plat->disable_irq(irq);
  318. free_irq(irq, armpmu);
  319. }
  320. }
  321. release_pmu(armpmu->type);
  322. }
  323. static int
  324. armpmu_reserve_hardware(struct arm_pmu *armpmu)
  325. {
  326. struct arm_pmu_platdata *plat;
  327. irq_handler_t handle_irq;
  328. int i, err, irq, irqs;
  329. struct platform_device *pmu_device = armpmu->plat_device;
  330. if (!pmu_device)
  331. return -ENODEV;
  332. err = reserve_pmu(armpmu->type);
  333. if (err) {
  334. pr_warning("unable to reserve pmu\n");
  335. return err;
  336. }
  337. plat = dev_get_platdata(&pmu_device->dev);
  338. if (plat && plat->handle_irq)
  339. handle_irq = armpmu_platform_irq;
  340. else
  341. handle_irq = armpmu->handle_irq;
  342. irqs = min(pmu_device->num_resources, num_possible_cpus());
  343. if (irqs < 1) {
  344. pr_err("no irqs for PMUs defined\n");
  345. return -ENODEV;
  346. }
  347. for (i = 0; i < irqs; ++i) {
  348. err = 0;
  349. irq = platform_get_irq(pmu_device, i);
  350. if (irq < 0)
  351. continue;
  352. /*
  353. * If we have a single PMU interrupt that we can't shift,
  354. * assume that we're running on a uniprocessor machine and
  355. * continue. Otherwise, continue without this interrupt.
  356. */
  357. if (irq_set_affinity(irq, cpumask_of(i)) && irqs > 1) {
  358. pr_warning("unable to set irq affinity (irq=%d, cpu=%u)\n",
  359. irq, i);
  360. continue;
  361. }
  362. err = request_irq(irq, handle_irq,
  363. IRQF_DISABLED | IRQF_NOBALANCING,
  364. "arm-pmu", armpmu);
  365. if (err) {
  366. pr_err("unable to request IRQ%d for ARM PMU counters\n",
  367. irq);
  368. armpmu_release_hardware(armpmu);
  369. return err;
  370. } else if (plat && plat->enable_irq)
  371. plat->enable_irq(irq);
  372. cpumask_set_cpu(i, &armpmu->active_irqs);
  373. }
  374. return 0;
  375. }
  376. static void
  377. hw_perf_event_destroy(struct perf_event *event)
  378. {
  379. struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
  380. atomic_t *active_events = &armpmu->active_events;
  381. struct mutex *pmu_reserve_mutex = &armpmu->reserve_mutex;
  382. if (atomic_dec_and_mutex_lock(active_events, pmu_reserve_mutex)) {
  383. armpmu_release_hardware(armpmu);
  384. mutex_unlock(pmu_reserve_mutex);
  385. }
  386. }
  387. static int
  388. event_requires_mode_exclusion(struct perf_event_attr *attr)
  389. {
  390. return attr->exclude_idle || attr->exclude_user ||
  391. attr->exclude_kernel || attr->exclude_hv;
  392. }
  393. static int
  394. __hw_perf_event_init(struct perf_event *event)
  395. {
  396. struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
  397. struct hw_perf_event *hwc = &event->hw;
  398. int mapping, err;
  399. mapping = armpmu->map_event(event);
  400. if (mapping < 0) {
  401. pr_debug("event %x:%llx not supported\n", event->attr.type,
  402. event->attr.config);
  403. return mapping;
  404. }
  405. /*
  406. * We don't assign an index until we actually place the event onto
  407. * hardware. Use -1 to signify that we haven't decided where to put it
  408. * yet. For SMP systems, each core has it's own PMU so we can't do any
  409. * clever allocation or constraints checking at this point.
  410. */
  411. hwc->idx = -1;
  412. hwc->config_base = 0;
  413. hwc->config = 0;
  414. hwc->event_base = 0;
  415. /*
  416. * Check whether we need to exclude the counter from certain modes.
  417. */
  418. if ((!armpmu->set_event_filter ||
  419. armpmu->set_event_filter(hwc, &event->attr)) &&
  420. event_requires_mode_exclusion(&event->attr)) {
  421. pr_debug("ARM performance counters do not support "
  422. "mode exclusion\n");
  423. return -EPERM;
  424. }
  425. /*
  426. * Store the event encoding into the config_base field.
  427. */
  428. hwc->config_base |= (unsigned long)mapping;
  429. if (!hwc->sample_period) {
  430. hwc->sample_period = armpmu->max_period;
  431. hwc->last_period = hwc->sample_period;
  432. local64_set(&hwc->period_left, hwc->sample_period);
  433. }
  434. err = 0;
  435. if (event->group_leader != event) {
  436. err = validate_group(event);
  437. if (err)
  438. return -EINVAL;
  439. }
  440. return err;
  441. }
  442. static int armpmu_event_init(struct perf_event *event)
  443. {
  444. struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
  445. int err = 0;
  446. atomic_t *active_events = &armpmu->active_events;
  447. if (armpmu->map_event(event) == -ENOENT)
  448. return -ENOENT;
  449. event->destroy = hw_perf_event_destroy;
  450. if (!atomic_inc_not_zero(active_events)) {
  451. mutex_lock(&armpmu->reserve_mutex);
  452. if (atomic_read(active_events) == 0)
  453. err = armpmu_reserve_hardware(armpmu);
  454. if (!err)
  455. atomic_inc(active_events);
  456. mutex_unlock(&armpmu->reserve_mutex);
  457. }
  458. if (err)
  459. return err;
  460. err = __hw_perf_event_init(event);
  461. if (err)
  462. hw_perf_event_destroy(event);
  463. return err;
  464. }
  465. static void armpmu_enable(struct pmu *pmu)
  466. {
  467. struct arm_pmu *armpmu = to_arm_pmu(pmu);
  468. struct pmu_hw_events *hw_events = armpmu->get_hw_events();
  469. int enabled = bitmap_weight(hw_events->used_mask, armpmu->num_events);
  470. if (enabled)
  471. armpmu->start();
  472. }
  473. static void armpmu_disable(struct pmu *pmu)
  474. {
  475. struct arm_pmu *armpmu = to_arm_pmu(pmu);
  476. armpmu->stop();
  477. }
  478. static void __init armpmu_init(struct arm_pmu *armpmu)
  479. {
  480. atomic_set(&armpmu->active_events, 0);
  481. mutex_init(&armpmu->reserve_mutex);
  482. armpmu->pmu = (struct pmu) {
  483. .pmu_enable = armpmu_enable,
  484. .pmu_disable = armpmu_disable,
  485. .event_init = armpmu_event_init,
  486. .add = armpmu_add,
  487. .del = armpmu_del,
  488. .start = armpmu_start,
  489. .stop = armpmu_stop,
  490. .read = armpmu_read,
  491. };
  492. }
  493. int __init armpmu_register(struct arm_pmu *armpmu, char *name, int type)
  494. {
  495. armpmu_init(armpmu);
  496. return perf_pmu_register(&armpmu->pmu, name, type);
  497. }
  498. /* Include the PMU-specific implementations. */
  499. #include "perf_event_xscale.c"
  500. #include "perf_event_v6.c"
  501. #include "perf_event_v7.c"
  502. /*
  503. * Ensure the PMU has sane values out of reset.
  504. * This requires SMP to be available, so exists as a separate initcall.
  505. */
  506. static int __init
  507. cpu_pmu_reset(void)
  508. {
  509. if (cpu_pmu && cpu_pmu->reset)
  510. return on_each_cpu(cpu_pmu->reset, NULL, 1);
  511. return 0;
  512. }
  513. arch_initcall(cpu_pmu_reset);
  514. /*
  515. * PMU platform driver and devicetree bindings.
  516. */
  517. static struct of_device_id armpmu_of_device_ids[] = {
  518. {.compatible = "arm,cortex-a9-pmu"},
  519. {.compatible = "arm,cortex-a8-pmu"},
  520. {.compatible = "arm,arm1136-pmu"},
  521. {.compatible = "arm,arm1176-pmu"},
  522. {},
  523. };
  524. static struct platform_device_id armpmu_plat_device_ids[] = {
  525. {.name = "arm-pmu"},
  526. {},
  527. };
  528. static int __devinit armpmu_device_probe(struct platform_device *pdev)
  529. {
  530. cpu_pmu->plat_device = pdev;
  531. return 0;
  532. }
  533. static struct platform_driver armpmu_driver = {
  534. .driver = {
  535. .name = "arm-pmu",
  536. .of_match_table = armpmu_of_device_ids,
  537. },
  538. .probe = armpmu_device_probe,
  539. .id_table = armpmu_plat_device_ids,
  540. };
  541. static int __init register_pmu_driver(void)
  542. {
  543. return platform_driver_register(&armpmu_driver);
  544. }
  545. device_initcall(register_pmu_driver);
  546. static struct pmu_hw_events *armpmu_get_cpu_events(void)
  547. {
  548. return &__get_cpu_var(cpu_hw_events);
  549. }
  550. static void __init cpu_pmu_init(struct arm_pmu *armpmu)
  551. {
  552. int cpu;
  553. for_each_possible_cpu(cpu) {
  554. struct pmu_hw_events *events = &per_cpu(cpu_hw_events, cpu);
  555. events->events = per_cpu(hw_events, cpu);
  556. events->used_mask = per_cpu(used_mask, cpu);
  557. raw_spin_lock_init(&events->pmu_lock);
  558. }
  559. armpmu->get_hw_events = armpmu_get_cpu_events;
  560. armpmu->type = ARM_PMU_DEVICE_CPU;
  561. }
  562. /*
  563. * CPU PMU identification and registration.
  564. */
  565. static int __init
  566. init_hw_perf_events(void)
  567. {
  568. unsigned long cpuid = read_cpuid_id();
  569. unsigned long implementor = (cpuid & 0xFF000000) >> 24;
  570. unsigned long part_number = (cpuid & 0xFFF0);
  571. /* ARM Ltd CPUs. */
  572. if (0x41 == implementor) {
  573. switch (part_number) {
  574. case 0xB360: /* ARM1136 */
  575. case 0xB560: /* ARM1156 */
  576. case 0xB760: /* ARM1176 */
  577. cpu_pmu = armv6pmu_init();
  578. break;
  579. case 0xB020: /* ARM11mpcore */
  580. cpu_pmu = armv6mpcore_pmu_init();
  581. break;
  582. case 0xC080: /* Cortex-A8 */
  583. cpu_pmu = armv7_a8_pmu_init();
  584. break;
  585. case 0xC090: /* Cortex-A9 */
  586. cpu_pmu = armv7_a9_pmu_init();
  587. break;
  588. case 0xC050: /* Cortex-A5 */
  589. cpu_pmu = armv7_a5_pmu_init();
  590. break;
  591. case 0xC0F0: /* Cortex-A15 */
  592. cpu_pmu = armv7_a15_pmu_init();
  593. break;
  594. }
  595. /* Intel CPUs [xscale]. */
  596. } else if (0x69 == implementor) {
  597. part_number = (cpuid >> 13) & 0x7;
  598. switch (part_number) {
  599. case 1:
  600. cpu_pmu = xscale1pmu_init();
  601. break;
  602. case 2:
  603. cpu_pmu = xscale2pmu_init();
  604. break;
  605. }
  606. }
  607. if (cpu_pmu) {
  608. pr_info("enabled with %s PMU driver, %d counters available\n",
  609. cpu_pmu->name, cpu_pmu->num_events);
  610. cpu_pmu_init(cpu_pmu);
  611. armpmu_register(cpu_pmu, "cpu", PERF_TYPE_RAW);
  612. } else {
  613. pr_info("no hardware support available\n");
  614. }
  615. return 0;
  616. }
  617. early_initcall(init_hw_perf_events);
  618. /*
  619. * Callchain handling code.
  620. */
  621. /*
  622. * The registers we're interested in are at the end of the variable
  623. * length saved register structure. The fp points at the end of this
  624. * structure so the address of this struct is:
  625. * (struct frame_tail *)(xxx->fp)-1
  626. *
  627. * This code has been adapted from the ARM OProfile support.
  628. */
  629. struct frame_tail {
  630. struct frame_tail __user *fp;
  631. unsigned long sp;
  632. unsigned long lr;
  633. } __attribute__((packed));
  634. /*
  635. * Get the return address for a single stackframe and return a pointer to the
  636. * next frame tail.
  637. */
  638. static struct frame_tail __user *
  639. user_backtrace(struct frame_tail __user *tail,
  640. struct perf_callchain_entry *entry)
  641. {
  642. struct frame_tail buftail;
  643. /* Also check accessibility of one struct frame_tail beyond */
  644. if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
  645. return NULL;
  646. if (__copy_from_user_inatomic(&buftail, tail, sizeof(buftail)))
  647. return NULL;
  648. perf_callchain_store(entry, buftail.lr);
  649. /*
  650. * Frame pointers should strictly progress back up the stack
  651. * (towards higher addresses).
  652. */
  653. if (tail + 1 >= buftail.fp)
  654. return NULL;
  655. return buftail.fp - 1;
  656. }
  657. void
  658. perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs)
  659. {
  660. struct frame_tail __user *tail;
  661. tail = (struct frame_tail __user *)regs->ARM_fp - 1;
  662. while ((entry->nr < PERF_MAX_STACK_DEPTH) &&
  663. tail && !((unsigned long)tail & 0x3))
  664. tail = user_backtrace(tail, entry);
  665. }
  666. /*
  667. * Gets called by walk_stackframe() for every stackframe. This will be called
  668. * whist unwinding the stackframe and is like a subroutine return so we use
  669. * the PC.
  670. */
  671. static int
  672. callchain_trace(struct stackframe *fr,
  673. void *data)
  674. {
  675. struct perf_callchain_entry *entry = data;
  676. perf_callchain_store(entry, fr->pc);
  677. return 0;
  678. }
  679. void
  680. perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs)
  681. {
  682. struct stackframe fr;
  683. fr.fp = regs->ARM_fp;
  684. fr.sp = regs->ARM_sp;
  685. fr.lr = regs->ARM_lr;
  686. fr.pc = regs->ARM_pc;
  687. walk_stackframe(&fr, callchain_trace, entry);
  688. }