root/drivers/hwtracing/coresight/coresight-etm-perf.c

DEFINITIONS

1. etm_event_cpu_path_ptr
2. etm_event_cpu_path
3. etm_event_read
4. etm_addr_filters_alloc
5. etm_event_destroy
6. etm_event_init
7. free_sink_buffer
8. free_event_data
9. alloc_event_data
10. etm_free_aux
11. etm_setup_aux
12. etm_event_start
13. etm_event_stop
14. etm_event_add
15. etm_event_del
16. etm_addr_filters_validate
17. etm_addr_filters_sync
18. etm_perf_symlink
19. etm_perf_sink_name_show
20. etm_perf_add_symlink_sink
21. etm_perf_del_symlink_sink
22. etm_perf_init

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright(C) 2015 Linaro Limited. All rights reserved.
   4  * Author: Mathieu Poirier <mathieu.poirier@linaro.org>
   5  */
   6 
   7 #include <linux/coresight.h>
   8 #include <linux/coresight-pmu.h>
   9 #include <linux/cpumask.h>
  10 #include <linux/device.h>
  11 #include <linux/list.h>
  12 #include <linux/mm.h>
  13 #include <linux/init.h>
  14 #include <linux/perf_event.h>
  15 #include <linux/percpu-defs.h>
  16 #include <linux/slab.h>
  17 #include <linux/stringhash.h>
  18 #include <linux/types.h>
  19 #include <linux/workqueue.h>
  20 
  21 #include "coresight-etm-perf.h"
  22 #include "coresight-priv.h"
  23 
  24 static struct pmu etm_pmu;
  25 static bool etm_perf_up;
  26 
  27 static DEFINE_PER_CPU(struct perf_output_handle, ctx_handle);
  28 static DEFINE_PER_CPU(struct coresight_device *, csdev_src);
  29 
  30 /* ETMv3.5/PTM's ETMCR is 'config' */
  31 PMU_FORMAT_ATTR(cycacc,         "config:" __stringify(ETM_OPT_CYCACC));
  32 PMU_FORMAT_ATTR(contextid,      "config:" __stringify(ETM_OPT_CTXTID));
  33 PMU_FORMAT_ATTR(timestamp,      "config:" __stringify(ETM_OPT_TS));
  34 PMU_FORMAT_ATTR(retstack,       "config:" __stringify(ETM_OPT_RETSTK));
  35 /* Sink ID - same for all ETMs */
  36 PMU_FORMAT_ATTR(sinkid,         "config2:0-31");
  37 
  38 static struct attribute *etm_config_formats_attr[] = {
  39         &format_attr_cycacc.attr,
  40         &format_attr_contextid.attr,
  41         &format_attr_timestamp.attr,
  42         &format_attr_retstack.attr,
  43         &format_attr_sinkid.attr,
  44         NULL,
  45 };
  46 
  47 static const struct attribute_group etm_pmu_format_group = {
  48         .name   = "format",
  49         .attrs  = etm_config_formats_attr,
  50 };
  51 
  52 static struct attribute *etm_config_sinks_attr[] = {
  53         NULL,
  54 };
  55 
  56 static const struct attribute_group etm_pmu_sinks_group = {
  57         .name   = "sinks",
  58         .attrs  = etm_config_sinks_attr,
  59 };
  60 
  61 static const struct attribute_group *etm_pmu_attr_groups[] = {
  62         &etm_pmu_format_group,
  63         &etm_pmu_sinks_group,
  64         NULL,
  65 };
  66 
  67 static inline struct list_head **
  68 etm_event_cpu_path_ptr(struct etm_event_data *data, int cpu)
  69 {
  70         return per_cpu_ptr(data->path, cpu);
  71 }
  72 
  73 static inline struct list_head *
  74 etm_event_cpu_path(struct etm_event_data *data, int cpu)
  75 {
  76         return *etm_event_cpu_path_ptr(data, cpu);
  77 }
  78 
  79 static void etm_event_read(struct perf_event *event) {}
  80 
  81 static int etm_addr_filters_alloc(struct perf_event *event)
  82 {
  83         struct etm_filters *filters;
  84         int node = event->cpu == -1 ? -1 : cpu_to_node(event->cpu);
  85 
  86         filters = kzalloc_node(sizeof(struct etm_filters), GFP_KERNEL, node);
  87         if (!filters)
  88                 return -ENOMEM;
  89 
  90         if (event->parent)
  91                 memcpy(filters, event->parent->hw.addr_filters,
  92                        sizeof(*filters));
  93 
  94         event->hw.addr_filters = filters;
  95 
  96         return 0;
  97 }
  98 
  99 static void etm_event_destroy(struct perf_event *event)
 100 {
 101         kfree(event->hw.addr_filters);
 102         event->hw.addr_filters = NULL;
 103 }
 104 
 105 static int etm_event_init(struct perf_event *event)
 106 {
 107         int ret = 0;
 108 
 109         if (event->attr.type != etm_pmu.type) {
 110                 ret = -ENOENT;
 111                 goto out;
 112         }
 113 
 114         ret = etm_addr_filters_alloc(event);
 115         if (ret)
 116                 goto out;
 117 
 118         event->destroy = etm_event_destroy;
 119 out:
 120         return ret;
 121 }
 122 
 123 static void free_sink_buffer(struct etm_event_data *event_data)
 124 {
 125         int cpu;
 126         cpumask_t *mask = &event_data->mask;
 127         struct coresight_device *sink;
 128 
 129         if (WARN_ON(cpumask_empty(mask)))
 130                 return;
 131 
 132         if (!event_data->snk_config)
 133                 return;
 134 
 135         cpu = cpumask_first(mask);
 136         sink = coresight_get_sink(etm_event_cpu_path(event_data, cpu));
 137         sink_ops(sink)->free_buffer(event_data->snk_config);
 138 }
 139 
 140 static void free_event_data(struct work_struct *work)
 141 {
 142         int cpu;
 143         cpumask_t *mask;
 144         struct etm_event_data *event_data;
 145 
 146         event_data = container_of(work, struct etm_event_data, work);
 147         mask = &event_data->mask;
 148 
 149         /* Free the sink buffers, if there are any */
 150         free_sink_buffer(event_data);
 151 
 152         for_each_cpu(cpu, mask) {
 153                 struct list_head **ppath;
 154 
 155                 ppath = etm_event_cpu_path_ptr(event_data, cpu);
 156                 if (!(IS_ERR_OR_NULL(*ppath)))
 157                         coresight_release_path(*ppath);
 158                 *ppath = NULL;
 159         }
 160 
 161         free_percpu(event_data->path);
 162         kfree(event_data);
 163 }
 164 
 165 static void *alloc_event_data(int cpu)
 166 {
 167         cpumask_t *mask;
 168         struct etm_event_data *event_data;
 169 
 170         /* First get memory for the session's data */
 171         event_data = kzalloc(sizeof(struct etm_event_data), GFP_KERNEL);
 172         if (!event_data)
 173                 return NULL;
 174 
 175 
 176         mask = &event_data->mask;
 177         if (cpu != -1)
 178                 cpumask_set_cpu(cpu, mask);
 179         else
 180                 cpumask_copy(mask, cpu_present_mask);
 181 
 182         /*
 183          * Each CPU has a single path between source and destination.  As such
 184          * allocate an array using CPU numbers as indexes.  That way a path
 185          * for any CPU can easily be accessed at any given time.  We proceed
 186          * the same way for sessions involving a single CPU.  The cost of
 187          * unused memory when dealing with single CPU trace scenarios is small
 188          * compared to the cost of searching through an optimized array.
 189          */
 190         event_data->path = alloc_percpu(struct list_head *);
 191 
 192         if (!event_data->path) {
 193                 kfree(event_data);
 194                 return NULL;
 195         }
 196 
 197         return event_data;
 198 }
 199 
 200 static void etm_free_aux(void *data)
 201 {
 202         struct etm_event_data *event_data = data;
 203 
 204         schedule_work(&event_data->work);
 205 }
 206 
 207 static void *etm_setup_aux(struct perf_event *event, void **pages,
 208                            int nr_pages, bool overwrite)
 209 {
 210         u32 id;
 211         int cpu = event->cpu;
 212         cpumask_t *mask;
 213         struct coresight_device *sink;
 214         struct etm_event_data *event_data = NULL;
 215 
 216         event_data = alloc_event_data(cpu);
 217         if (!event_data)
 218                 return NULL;
 219         INIT_WORK(&event_data->work, free_event_data);
 220 
 221         /* First get the selected sink from user space. */
 222         if (event->attr.config2) {
 223                 id = (u32)event->attr.config2;
 224                 sink = coresight_get_sink_by_id(id);
 225         } else {
 226                 sink = coresight_get_enabled_sink(true);
 227         }
 228 
 229         if (!sink)
 230                 goto err;
 231 
 232         mask = &event_data->mask;
 233 
 234         /*
 235          * Setup the path for each CPU in a trace session. We try to build
 236          * trace path for each CPU in the mask. If we don't find an ETM
 237          * for the CPU or fail to build a path, we clear the CPU from the
 238          * mask and continue with the rest. If ever we try to trace on those
 239          * CPUs, we can handle it and fail the session.
 240          */
 241         for_each_cpu(cpu, mask) {
 242                 struct list_head *path;
 243                 struct coresight_device *csdev;
 244 
 245                 csdev = per_cpu(csdev_src, cpu);
 246                 /*
 247                  * If there is no ETM associated with this CPU clear it from
 248                  * the mask and continue with the rest. If ever we try to trace
 249                  * on this CPU, we handle it accordingly.
 250                  */
 251                 if (!csdev) {
 252                         cpumask_clear_cpu(cpu, mask);
 253                         continue;
 254                 }
 255 
 256                 /*
 257                  * Building a path doesn't enable it, it simply builds a
 258                  * list of devices from source to sink that can be
 259                  * referenced later when the path is actually needed.
 260                  */
 261                 path = coresight_build_path(csdev, sink);
 262                 if (IS_ERR(path)) {
 263                         cpumask_clear_cpu(cpu, mask);
 264                         continue;
 265                 }
 266 
 267                 *etm_event_cpu_path_ptr(event_data, cpu) = path;
 268         }
 269 
 270         /* If we don't have any CPUs ready for tracing, abort */
 271         cpu = cpumask_first(mask);
 272         if (cpu >= nr_cpu_ids)
 273                 goto err;
 274 
 275         if (!sink_ops(sink)->alloc_buffer || !sink_ops(sink)->free_buffer)
 276                 goto err;
 277 
 278         /* Allocate the sink buffer for this session */
 279         event_data->snk_config =
 280                         sink_ops(sink)->alloc_buffer(sink, event, pages,
 281                                                      nr_pages, overwrite);
 282         if (!event_data->snk_config)
 283                 goto err;
 284 
 285 out:
 286         return event_data;
 287 
 288 err:
 289         etm_free_aux(event_data);
 290         event_data = NULL;
 291         goto out;
 292 }
 293 
 294 static void etm_event_start(struct perf_event *event, int flags)
 295 {
 296         int cpu = smp_processor_id();
 297         struct etm_event_data *event_data;
 298         struct perf_output_handle *handle = this_cpu_ptr(&ctx_handle);
 299         struct coresight_device *sink, *csdev = per_cpu(csdev_src, cpu);
 300         struct list_head *path;
 301 
 302         if (!csdev)
 303                 goto fail;
 304 
 305         /*
 306          * Deal with the ring buffer API and get a handle on the
 307          * session's information.
 308          */
 309         event_data = perf_aux_output_begin(handle, event);
 310         if (!event_data)
 311                 goto fail;
 312 
 313         path = etm_event_cpu_path(event_data, cpu);
 314         /* We need a sink, no need to continue without one */
 315         sink = coresight_get_sink(path);
 316         if (WARN_ON_ONCE(!sink))
 317                 goto fail_end_stop;
 318 
 319         /* Nothing will happen without a path */
 320         if (coresight_enable_path(path, CS_MODE_PERF, handle))
 321                 goto fail_end_stop;
 322 
 323         /* Tell the perf core the event is alive */
 324         event->hw.state = 0;
 325 
 326         /* Finally enable the tracer */
 327         if (source_ops(csdev)->enable(csdev, event, CS_MODE_PERF))
 328                 goto fail_disable_path;
 329 
 330 out:
 331         return;
 332 
 333 fail_disable_path:
 334         coresight_disable_path(path);
 335 fail_end_stop:
 336         perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
 337         perf_aux_output_end(handle, 0);
 338 fail:
 339         event->hw.state = PERF_HES_STOPPED;
 340         goto out;
 341 }
 342 
 343 static void etm_event_stop(struct perf_event *event, int mode)
 344 {
 345         int cpu = smp_processor_id();
 346         unsigned long size;
 347         struct coresight_device *sink, *csdev = per_cpu(csdev_src, cpu);
 348         struct perf_output_handle *handle = this_cpu_ptr(&ctx_handle);
 349         struct etm_event_data *event_data = perf_get_aux(handle);
 350         struct list_head *path;
 351 
 352         if (event->hw.state == PERF_HES_STOPPED)
 353                 return;
 354 
 355         if (!csdev)
 356                 return;
 357 
 358         path = etm_event_cpu_path(event_data, cpu);
 359         if (!path)
 360                 return;
 361 
 362         sink = coresight_get_sink(path);
 363         if (!sink)
 364                 return;
 365 
 366         /* stop tracer */
 367         source_ops(csdev)->disable(csdev, event);
 368 
 369         /* tell the core */
 370         event->hw.state = PERF_HES_STOPPED;
 371 
 372         if (mode & PERF_EF_UPDATE) {
 373                 if (WARN_ON_ONCE(handle->event != event))
 374                         return;
 375 
 376                 /* update trace information */
 377                 if (!sink_ops(sink)->update_buffer)
 378                         return;
 379 
 380                 size = sink_ops(sink)->update_buffer(sink, handle,
 381                                               event_data->snk_config);
 382                 perf_aux_output_end(handle, size);
 383         }
 384 
 385         /* Disabling the path make its elements available to other sessions */
 386         coresight_disable_path(path);
 387 }
 388 
 389 static int etm_event_add(struct perf_event *event, int mode)
 390 {
 391         int ret = 0;
 392         struct hw_perf_event *hwc = &event->hw;
 393 
 394         if (mode & PERF_EF_START) {
 395                 etm_event_start(event, 0);
 396                 if (hwc->state & PERF_HES_STOPPED)
 397                         ret = -EINVAL;
 398         } else {
 399                 hwc->state = PERF_HES_STOPPED;
 400         }
 401 
 402         return ret;
 403 }
 404 
 405 static void etm_event_del(struct perf_event *event, int mode)
 406 {
 407         etm_event_stop(event, PERF_EF_UPDATE);
 408 }
 409 
 410 static int etm_addr_filters_validate(struct list_head *filters)
 411 {
 412         bool range = false, address = false;
 413         int index = 0;
 414         struct perf_addr_filter *filter;
 415 
 416         list_for_each_entry(filter, filters, entry) {
 417                 /*
 418                  * No need to go further if there's no more
 419                  * room for filters.
 420                  */
 421                 if (++index > ETM_ADDR_CMP_MAX)
 422                         return -EOPNOTSUPP;
 423 
 424                 /* filter::size==0 means single address trigger */
 425                 if (filter->size) {
 426                         /*
 427                          * The existing code relies on START/STOP filters
 428                          * being address filters.
 429                          */
 430                         if (filter->action == PERF_ADDR_FILTER_ACTION_START ||
 431                             filter->action == PERF_ADDR_FILTER_ACTION_STOP)
 432                                 return -EOPNOTSUPP;
 433 
 434                         range = true;
 435                 } else
 436                         address = true;
 437 
 438                 /*
 439                  * At this time we don't allow range and start/stop filtering
 440                  * to cohabitate, they have to be mutually exclusive.
 441                  */
 442                 if (range && address)
 443                         return -EOPNOTSUPP;
 444         }
 445 
 446         return 0;
 447 }
 448 
 449 static void etm_addr_filters_sync(struct perf_event *event)
 450 {
 451         struct perf_addr_filters_head *head = perf_event_addr_filters(event);
 452         unsigned long start, stop;
 453         struct perf_addr_filter_range *fr = event->addr_filter_ranges;
 454         struct etm_filters *filters = event->hw.addr_filters;
 455         struct etm_filter *etm_filter;
 456         struct perf_addr_filter *filter;
 457         int i = 0;
 458 
 459         list_for_each_entry(filter, &head->list, entry) {
 460                 start = fr[i].start;
 461                 stop = start + fr[i].size;
 462                 etm_filter = &filters->etm_filter[i];
 463 
 464                 switch (filter->action) {
 465                 case PERF_ADDR_FILTER_ACTION_FILTER:
 466                         etm_filter->start_addr = start;
 467                         etm_filter->stop_addr = stop;
 468                         etm_filter->type = ETM_ADDR_TYPE_RANGE;
 469                         break;
 470                 case PERF_ADDR_FILTER_ACTION_START:
 471                         etm_filter->start_addr = start;
 472                         etm_filter->type = ETM_ADDR_TYPE_START;
 473                         break;
 474                 case PERF_ADDR_FILTER_ACTION_STOP:
 475                         etm_filter->stop_addr = stop;
 476                         etm_filter->type = ETM_ADDR_TYPE_STOP;
 477                         break;
 478                 }
 479                 i++;
 480         }
 481 
 482         filters->nr_filters = i;
 483 }
 484 
 485 int etm_perf_symlink(struct coresight_device *csdev, bool link)
 486 {
 487         char entry[sizeof("cpu9999999")];
 488         int ret = 0, cpu = source_ops(csdev)->cpu_id(csdev);
 489         struct device *pmu_dev = etm_pmu.dev;
 490         struct device *cs_dev = &csdev->dev;
 491 
 492         sprintf(entry, "cpu%d", cpu);
 493 
 494         if (!etm_perf_up)
 495                 return -EPROBE_DEFER;
 496 
 497         if (link) {
 498                 ret = sysfs_create_link(&pmu_dev->kobj, &cs_dev->kobj, entry);
 499                 if (ret)
 500                         return ret;
 501                 per_cpu(csdev_src, cpu) = csdev;
 502         } else {
 503                 sysfs_remove_link(&pmu_dev->kobj, entry);
 504                 per_cpu(csdev_src, cpu) = NULL;
 505         }
 506 
 507         return 0;
 508 }
 509 
 510 static ssize_t etm_perf_sink_name_show(struct device *dev,
 511                                        struct device_attribute *dattr,
 512                                        char *buf)
 513 {
 514         struct dev_ext_attribute *ea;
 515 
 516         ea = container_of(dattr, struct dev_ext_attribute, attr);
 517         return scnprintf(buf, PAGE_SIZE, "0x%lx\n", (unsigned long)(ea->var));
 518 }
 519 
 520 int etm_perf_add_symlink_sink(struct coresight_device *csdev)
 521 {
 522         int ret;
 523         unsigned long hash;
 524         const char *name;
 525         struct device *pmu_dev = etm_pmu.dev;
 526         struct device *dev = &csdev->dev;
 527         struct dev_ext_attribute *ea;
 528 
 529         if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
 530             csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
 531                 return -EINVAL;
 532 
 533         if (csdev->ea != NULL)
 534                 return -EINVAL;
 535 
 536         if (!etm_perf_up)
 537                 return -EPROBE_DEFER;
 538 
 539         ea = devm_kzalloc(dev, sizeof(*ea), GFP_KERNEL);
 540         if (!ea)
 541                 return -ENOMEM;
 542 
 543         name = dev_name(dev);
 544         /* See function coresight_get_sink_by_id() to know where this is used */
 545         hash = hashlen_hash(hashlen_string(NULL, name));
 546 
 547         sysfs_attr_init(&ea->attr.attr);
 548         ea->attr.attr.name = devm_kstrdup(dev, name, GFP_KERNEL);
 549         if (!ea->attr.attr.name)
 550                 return -ENOMEM;
 551 
 552         ea->attr.attr.mode = 0444;
 553         ea->attr.show = etm_perf_sink_name_show;
 554         ea->var = (unsigned long *)hash;
 555 
 556         ret = sysfs_add_file_to_group(&pmu_dev->kobj,
 557                                       &ea->attr.attr, "sinks");
 558 
 559         if (!ret)
 560                 csdev->ea = ea;
 561 
 562         return ret;
 563 }
 564 
 565 void etm_perf_del_symlink_sink(struct coresight_device *csdev)
 566 {
 567         struct device *pmu_dev = etm_pmu.dev;
 568         struct dev_ext_attribute *ea = csdev->ea;
 569 
 570         if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
 571             csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
 572                 return;
 573 
 574         if (!ea)
 575                 return;
 576 
 577         sysfs_remove_file_from_group(&pmu_dev->kobj,
 578                                      &ea->attr.attr, "sinks");
 579         csdev->ea = NULL;
 580 }
 581 
 582 static int __init etm_perf_init(void)
 583 {
 584         int ret;
 585 
 586         etm_pmu.capabilities            = (PERF_PMU_CAP_EXCLUSIVE |
 587                                            PERF_PMU_CAP_ITRACE);
 588 
 589         etm_pmu.attr_groups             = etm_pmu_attr_groups;
 590         etm_pmu.task_ctx_nr             = perf_sw_context;
 591         etm_pmu.read                    = etm_event_read;
 592         etm_pmu.event_init              = etm_event_init;
 593         etm_pmu.setup_aux               = etm_setup_aux;
 594         etm_pmu.free_aux                = etm_free_aux;
 595         etm_pmu.start                   = etm_event_start;
 596         etm_pmu.stop                    = etm_event_stop;
 597         etm_pmu.add                     = etm_event_add;
 598         etm_pmu.del                     = etm_event_del;
 599         etm_pmu.addr_filters_sync       = etm_addr_filters_sync;
 600         etm_pmu.addr_filters_validate   = etm_addr_filters_validate;
 601         etm_pmu.nr_addr_filters         = ETM_ADDR_CMP_MAX;
 602 
 603         ret = perf_pmu_register(&etm_pmu, CORESIGHT_ETM_PMU_NAME, -1);
 604         if (ret == 0)
 605                 etm_perf_up = true;
 606 
 607         return ret;
 608 }
 609 device_initcall(etm_perf_init);