tools/perf/arch/arm/util/cs-etm.c

   1 /*
   2  * Copyright(C) 2015 Linaro Limited. All rights reserved.
   3  * Author: Mathieu Poirier <mathieu.poirier@linaro.org>
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 as published by
   7  * the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along with
  15  * this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include <api/fs/fs.h>
  19 #include <linux/bitops.h>
  20 #include <linux/coresight-pmu.h>
  21 #include <linux/kernel.h>
  22 #include <linux/log2.h>
  23 #include <linux/types.h>
  24
  25 #include "cs-etm.h"
  26 #include "../../perf.h"
  27 #include "../../util/auxtrace.h"
  28 #include "../../util/cpumap.h"
  29 #include "../../util/evlist.h"
  30 #include "../../util/evsel.h"
  31 #include "../../util/pmu.h"
  32 #include "../../util/thread_map.h"
  33 #include "../../util/cs-etm.h"
  34
  35 #include <stdlib.h>
  36
  37 #define ENABLE_SINK_MAX 128
  38 #define CS_BUS_DEVICE_PATH "/bus/coresight/devices/"
  39
  40 struct cs_etm_recording {
  41         struct auxtrace_record  itr;
  42         struct perf_pmu         *cs_etm_pmu;
  43         struct perf_evlist      *evlist;
  44         bool                    snapshot_mode;
  45         size_t                  snapshot_size;
  46 };
  47
  48 static bool cs_etm_is_etmv4(struct auxtrace_record *itr, int cpu);
  49
  50 static int cs_etm_parse_snapshot_options(struct auxtrace_record *itr,
  51                                          struct record_opts *opts,
  52                                          const char *str)
  53 {
  54         struct cs_etm_recording *ptr =
  55                                 container_of(itr, struct cs_etm_recording, itr);
  56         unsigned long long snapshot_size = 0;
  57         char *endptr;
  58
  59         if (str) {
  60                 snapshot_size = strtoull(str, &endptr, 0);
  61                 if (*endptr || snapshot_size > SIZE_MAX)
  62                         return -1;
  63         }
  64
  65         opts->auxtrace_snapshot_mode = true;
  66         opts->auxtrace_snapshot_size = snapshot_size;
  67         ptr->snapshot_size = snapshot_size;
  68
  69         return 0;
  70 }
  71
  72 static int cs_etm_recording_options(struct auxtrace_record *itr,
  73                                     struct perf_evlist *evlist,
  74                                     struct record_opts *opts)
  75 {
  76         struct cs_etm_recording *ptr =
  77                                 container_of(itr, struct cs_etm_recording, itr);
  78         struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
  79         struct perf_evsel *evsel, *cs_etm_evsel = NULL;
  80         const struct cpu_map *cpus = evlist->cpus;
  81         bool privileged = (geteuid() == 0 || perf_event_paranoid() < 0);
  82
  83         ptr->evlist = evlist;
  84         ptr->snapshot_mode = opts->auxtrace_snapshot_mode;
  85
  86         evlist__for_each_entry(evlist, evsel) {
  87                 if (evsel->attr.type == cs_etm_pmu->type) {
  88                         if (cs_etm_evsel) {
  89                                 pr_err("There may be only one %s event\n",
  90                                        CORESIGHT_ETM_PMU_NAME);
  91                                 return -EINVAL;
  92                         }
  93                         evsel->attr.freq = 0;
  94                         evsel->attr.sample_period = 1;
  95                         cs_etm_evsel = evsel;
  96                         opts->full_auxtrace = true;
  97                 }
  98         }
  99
 100         /* no need to continue if at least one event of interest was found */
 101         if (!cs_etm_evsel)
 102                 return 0;
 103
 104         if (opts->use_clockid) {
 105                 pr_err("Cannot use clockid (-k option) with %s\n",
 106                        CORESIGHT_ETM_PMU_NAME);
 107                 return -EINVAL;
 108         }
 109
 110         /* we are in snapshot mode */
 111         if (opts->auxtrace_snapshot_mode) {
 112                 /*
 113                  * No size were given to '-S' or '-m,', so go with
 114                  * the default
 115                  */
 116                 if (!opts->auxtrace_snapshot_size &&
 117                     !opts->auxtrace_mmap_pages) {
 118                         if (privileged) {
 119                                 opts->auxtrace_mmap_pages = MiB(4) / page_size;
 120                         } else {
 121                                 opts->auxtrace_mmap_pages =
 122                                                         KiB(128) / page_size;
 123                                 if (opts->mmap_pages == UINT_MAX)
 124                                         opts->mmap_pages = KiB(256) / page_size;
 125                         }
 126                 } else if (!opts->auxtrace_mmap_pages && !privileged &&
 127                                                 opts->mmap_pages == UINT_MAX) {
 128                         opts->mmap_pages = KiB(256) / page_size;
 129                 }
 130
 131                 /*
 132                  * '-m,xyz' was specified but no snapshot size, so make the
 133                  * snapshot size as big as the auxtrace mmap area.
 134                  */
 135                 if (!opts->auxtrace_snapshot_size) {
 136                         opts->auxtrace_snapshot_size =
 137                                 opts->auxtrace_mmap_pages * (size_t)page_size;
 138                 }
 139
 140                 /*
 141                  * -Sxyz was specified but no auxtrace mmap area, so make the
 142                  * auxtrace mmap area big enough to fit the requested snapshot
 143                  * size.
 144                  */
 145                 if (!opts->auxtrace_mmap_pages) {
 146                         size_t sz = opts->auxtrace_snapshot_size;
 147
 148                         sz = round_up(sz, page_size) / page_size;
 149                         opts->auxtrace_mmap_pages = roundup_pow_of_two(sz);
 150                 }
 151
 152                 /* Snapshost size can't be bigger than the auxtrace area */
 153                 if (opts->auxtrace_snapshot_size >
 154                                 opts->auxtrace_mmap_pages * (size_t)page_size) {
 155                         pr_err("Snapshot size %zu must not be greater than AUX area tracing mmap size %zu\n",
 156                                opts->auxtrace_snapshot_size,
 157                                opts->auxtrace_mmap_pages * (size_t)page_size);
 158                         return -EINVAL;
 159                 }
 160
 161                 /* Something went wrong somewhere - this shouldn't happen */
 162                 if (!opts->auxtrace_snapshot_size ||
 163                     !opts->auxtrace_mmap_pages) {
 164                         pr_err("Failed to calculate default snapshot size and/or AUX area tracing mmap pages\n");
 165                         return -EINVAL;
 166                 }
 167         }
 168
 169         /* We are in full trace mode but '-m,xyz' wasn't specified */
 170         if (opts->full_auxtrace && !opts->auxtrace_mmap_pages) {
 171                 if (privileged) {
 172                         opts->auxtrace_mmap_pages = MiB(4) / page_size;
 173                 } else {
 174                         opts->auxtrace_mmap_pages = KiB(128) / page_size;
 175                         if (opts->mmap_pages == UINT_MAX)
 176                                 opts->mmap_pages = KiB(256) / page_size;
 177                 }
 178
 179         }
 180
 181         /* Validate auxtrace_mmap_pages provided by user */
 182         if (opts->auxtrace_mmap_pages) {
 183                 unsigned int max_page = (KiB(128) / page_size);
 184                 size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size;
 185
 186                 if (!privileged &&
 187                     opts->auxtrace_mmap_pages > max_page) {
 188                         opts->auxtrace_mmap_pages = max_page;
 189                         pr_err("auxtrace too big, truncating to %d\n",
 190                                max_page);
 191                 }
 192
 193                 if (!is_power_of_2(sz)) {
 194                         pr_err("Invalid mmap size for %s: must be a power of 2\n",
 195                                CORESIGHT_ETM_PMU_NAME);
 196                         return -EINVAL;
 197                 }
 198         }
 199
 200         if (opts->auxtrace_snapshot_mode)
 201                 pr_debug2("%s snapshot size: %zu\n", CORESIGHT_ETM_PMU_NAME,
 202                           opts->auxtrace_snapshot_size);
 203
 204         if (cs_etm_evsel) {
 205                 /*
 206                  * To obtain the auxtrace buffer file descriptor, the auxtrace
 207                  * event must come first.
 208                  */
 209                 perf_evlist__to_front(evlist, cs_etm_evsel);
 210                 /*
 211                  * In the case of per-cpu mmaps, we need the CPU on the
 212                  * AUX event.
 213                  */
 214                 if (!cpu_map__empty(cpus))
 215                         perf_evsel__set_sample_bit(cs_etm_evsel, CPU);
 216         }
 217
 218         /* Add dummy event to keep tracking */
 219         if (opts->full_auxtrace) {
 220                 struct perf_evsel *tracking_evsel;
 221                 int err;
 222
 223                 err = parse_events(evlist, "dummy:u", NULL);
 224                 if (err)
 225                         return err;
 226
 227                 tracking_evsel = perf_evlist__last(evlist);
 228                 perf_evlist__set_tracking_event(evlist, tracking_evsel);
 229
 230                 tracking_evsel->attr.freq = 0;
 231                 tracking_evsel->attr.sample_period = 1;
 232
 233                 /* In per-cpu case, always need the time of mmap events etc */
 234                 if (!cpu_map__empty(cpus))
 235                         perf_evsel__set_sample_bit(tracking_evsel, TIME);
 236         }
 237
 238         return 0;
 239 }
 240
 241 static u64 cs_etm_get_config(struct auxtrace_record *itr)
 242 {
 243         u64 config = 0;
 244         struct cs_etm_recording *ptr =
 245                         container_of(itr, struct cs_etm_recording, itr);
 246         struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
 247         struct perf_evlist *evlist = ptr->evlist;
 248         struct perf_evsel *evsel;
 249
 250         evlist__for_each_entry(evlist, evsel) {
 251                 if (evsel->attr.type == cs_etm_pmu->type) {
 252                         /*
 253                          * Variable perf_event_attr::config is assigned to
 254                          * ETMv3/PTM.  The bit fields have been made to match
 255                          * the ETMv3.5 ETRMCR register specification.  See the
 256                          * PMU_FORMAT_ATTR() declarations in
 257                          * drivers/hwtracing/coresight/coresight-perf.c for
 258                          * details.
 259                          */
 260                         config = evsel->attr.config;
 261                         break;
 262                 }
 263         }
 264
 265         return config;
 266 }
 267
 268 static size_t
 269 cs_etm_info_priv_size(struct auxtrace_record *itr __maybe_unused,
 270                       struct perf_evlist *evlist __maybe_unused)
 271 {
 272         int i;
 273         int etmv3 = 0, etmv4 = 0;
 274         const struct cpu_map *cpus = evlist->cpus;
 275
 276         /* cpu map is not empty, we have specific CPUs to work with */
 277         if (!cpu_map__empty(cpus)) {
 278                 for (i = 0; i < cpu_map__nr(cpus); i++) {
 279                         if (cs_etm_is_etmv4(itr, cpus->map[i]))
 280                                 etmv4++;
 281                         else
 282                                 etmv3++;
 283                 }
 284         } else {
 285                 /* get configuration for all CPUs in the system */
 286                 for (i = 0; i < cpu__max_cpu(); i++) {
 287                         if (cs_etm_is_etmv4(itr, i))
 288                                 etmv4++;
 289                         else
 290                                 etmv3++;
 291                 }
 292         }
 293
 294         return (CS_ETM_HEADER_SIZE +
 295                (etmv4 * CS_ETMV4_PRIV_SIZE) +
 296                (etmv3 * CS_ETMV3_PRIV_SIZE));
 297 }
 298
 299 static const char *metadata_etmv3_ro[CS_ETM_PRIV_MAX] = {
 300         [CS_ETM_ETMCCER]        = "mgmt/etmccer",
 301         [CS_ETM_ETMIDR]         = "mgmt/etmidr",
 302 };
 303
 304 static const char *metadata_etmv4_ro[CS_ETMV4_PRIV_MAX] = {
 305         [CS_ETMV4_TRCIDR0]              = "trcidr/trcidr0",
 306         [CS_ETMV4_TRCIDR1]              = "trcidr/trcidr1",
 307         [CS_ETMV4_TRCIDR2]              = "trcidr/trcidr2",
 308         [CS_ETMV4_TRCIDR8]              = "trcidr/trcidr8",
 309         [CS_ETMV4_TRCAUTHSTATUS]        = "mgmt/trcauthstatus",
 310 };
 311
 312 static bool cs_etm_is_etmv4(struct auxtrace_record *itr, int cpu)
 313 {
 314         bool ret = false;
 315         char path[PATH_MAX];
 316         int scan;
 317         unsigned int val;
 318         struct cs_etm_recording *ptr =
 319                         container_of(itr, struct cs_etm_recording, itr);
 320         struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
 321
 322         /* Take any of the RO files for ETMv4 and see if it present */
 323         snprintf(path, PATH_MAX, "cpu%d/%s",
 324                  cpu, metadata_etmv4_ro[CS_ETMV4_TRCIDR0]);
 325         scan = perf_pmu__scan_file(cs_etm_pmu, path, "%x", &val);
 326
 327         /* The file was read successfully, we have a winner */
 328         if (scan == 1)
 329                 ret = true;
 330
 331         return ret;
 332 }
 333
 334 static int cs_etm_get_ro(struct perf_pmu *pmu, int cpu, const char *path)
 335 {
 336         char pmu_path[PATH_MAX];
 337         int scan;
 338         unsigned int val = 0;
 339
 340         /* Get RO metadata from sysfs */
 341         snprintf(pmu_path, PATH_MAX, "cpu%d/%s", cpu, path);
 342
 343         scan = perf_pmu__scan_file(pmu, pmu_path, "%x", &val);
 344         if (scan != 1)
 345                 pr_err("%s: error reading: %s\n", __func__, pmu_path);
 346
 347         return val;
 348 }
 349
 350 static void cs_etm_get_metadata(int cpu, u32 *offset,
 351                                 struct auxtrace_record *itr,
 352                                 struct auxtrace_info_event *info)
 353 {
 354         u32 increment;
 355         u64 magic;
 356         struct cs_etm_recording *ptr =
 357                         container_of(itr, struct cs_etm_recording, itr);
 358         struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
 359
 360         /* first see what kind of tracer this cpu is affined to */
 361         if (cs_etm_is_etmv4(itr, cpu)) {
 362                 magic = __perf_cs_etmv4_magic;
 363                 /* Get trace configuration register */
 364                 info->priv[*offset + CS_ETMV4_TRCCONFIGR] =
 365                                                 cs_etm_get_config(itr);
 366                 /* Get traceID from the framework */
 367                 info->priv[*offset + CS_ETMV4_TRCTRACEIDR] =
 368                                                 coresight_get_trace_id(cpu);
 369                 /* Get read-only information from sysFS */
 370                 info->priv[*offset + CS_ETMV4_TRCIDR0] =
 371                         cs_etm_get_ro(cs_etm_pmu, cpu,
 372                                       metadata_etmv4_ro[CS_ETMV4_TRCIDR0]);
 373                 info->priv[*offset + CS_ETMV4_TRCIDR1] =
 374                         cs_etm_get_ro(cs_etm_pmu, cpu,
 375                                       metadata_etmv4_ro[CS_ETMV4_TRCIDR1]);
 376                 info->priv[*offset + CS_ETMV4_TRCIDR2] =
 377                         cs_etm_get_ro(cs_etm_pmu, cpu,
 378                                       metadata_etmv4_ro[CS_ETMV4_TRCIDR2]);
 379                 info->priv[*offset + CS_ETMV4_TRCIDR8] =
 380                         cs_etm_get_ro(cs_etm_pmu, cpu,
 381                                       metadata_etmv4_ro[CS_ETMV4_TRCIDR8]);
 382                 info->priv[*offset + CS_ETMV4_TRCAUTHSTATUS] =
 383                         cs_etm_get_ro(cs_etm_pmu, cpu,
 384                                       metadata_etmv4_ro
 385                                       [CS_ETMV4_TRCAUTHSTATUS]);
 386
 387                 /* How much space was used */
 388                 increment = CS_ETMV4_PRIV_MAX;
 389         } else {
 390                 magic = __perf_cs_etmv3_magic;
 391                 /* Get configuration register */
 392                 info->priv[*offset + CS_ETM_ETMCR] = cs_etm_get_config(itr);
 393                 /* Get traceID from the framework */
 394                 info->priv[*offset + CS_ETM_ETMTRACEIDR] =
 395                                                 coresight_get_trace_id(cpu);
 396                 /* Get read-only information from sysFS */
 397                 info->priv[*offset + CS_ETM_ETMCCER] =
 398                         cs_etm_get_ro(cs_etm_pmu, cpu,
 399                                       metadata_etmv3_ro[CS_ETM_ETMCCER]);
 400                 info->priv[*offset + CS_ETM_ETMIDR] =
 401                         cs_etm_get_ro(cs_etm_pmu, cpu,
 402                                       metadata_etmv3_ro[CS_ETM_ETMIDR]);
 403
 404                 /* How much space was used */
 405                 increment = CS_ETM_PRIV_MAX;
 406         }
 407
 408         /* Build generic header portion */
 409         info->priv[*offset + CS_ETM_MAGIC] = magic;
 410         info->priv[*offset + CS_ETM_CPU] = cpu;
 411         /* Where the next CPU entry should start from */
 412         *offset += increment;
 413 }
 414
 415 static int cs_etm_info_fill(struct auxtrace_record *itr,
 416                             struct perf_session *session,
 417                             struct auxtrace_info_event *info,
 418                             size_t priv_size)
 419 {
 420         int i;
 421         u32 offset;
 422         u64 nr_cpu, type;
 423         const struct cpu_map *cpus = session->evlist->cpus;
 424         struct cs_etm_recording *ptr =
 425                         container_of(itr, struct cs_etm_recording, itr);
 426         struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
 427
 428         if (priv_size != cs_etm_info_priv_size(itr, session->evlist))
 429                 return -EINVAL;
 430
 431         if (!session->evlist->nr_mmaps)
 432                 return -EINVAL;
 433
 434         /* If the cpu_map is empty all CPUs are involved */
 435         nr_cpu = cpu_map__empty(cpus) ? cpu__max_cpu() : cpu_map__nr(cpus);
 436         /* Get PMU type as dynamically assigned by the core */
 437         type = cs_etm_pmu->type;
 438
 439         /* First fill out the session header */
 440         info->type = PERF_AUXTRACE_CS_ETM;
 441         info->priv[CS_HEADER_VERSION_0] = 0;
 442         info->priv[CS_PMU_TYPE_CPUS] = type << 32;
 443         info->priv[CS_PMU_TYPE_CPUS] |= nr_cpu;
 444         info->priv[CS_ETM_SNAPSHOT] = ptr->snapshot_mode;
 445
 446         offset = CS_ETM_SNAPSHOT + 1;
 447
 448         /* cpu map is not empty, we have specific CPUs to work with */
 449         if (!cpu_map__empty(cpus)) {
 450                 for (i = 0; i < cpu_map__nr(cpus) && offset < priv_size; i++)
 451                         cs_etm_get_metadata(cpus->map[i], &offset, itr, info);
 452         } else {
 453                 /* get configuration for all CPUs in the system */
 454                 for (i = 0; i < cpu__max_cpu(); i++)
 455                         cs_etm_get_metadata(i, &offset, itr, info);
 456         }
 457
 458         return 0;
 459 }
 460
 461 static int cs_etm_find_snapshot(struct auxtrace_record *itr __maybe_unused,
 462                                 int idx, struct auxtrace_mmap *mm,
 463                                 unsigned char *data __maybe_unused,
 464                                 u64 *head, u64 *old)
 465 {
 466         pr_debug3("%s: mmap index %d old head %zu new head %zu size %zu\n",
 467                   __func__, idx, (size_t)*old, (size_t)*head, mm->len);
 468
 469         *old = *head;
 470         *head += mm->len;
 471
 472         return 0;
 473 }
 474
 475 static int cs_etm_snapshot_start(struct auxtrace_record *itr)
 476 {
 477         struct cs_etm_recording *ptr =
 478                         container_of(itr, struct cs_etm_recording, itr);
 479         struct perf_evsel *evsel;
 480
 481         evlist__for_each_entry(ptr->evlist, evsel) {
 482                 if (evsel->attr.type == ptr->cs_etm_pmu->type)
 483                         return perf_evsel__disable(evsel);
 484         }
 485         return -EINVAL;
 486 }
 487
 488 static int cs_etm_snapshot_finish(struct auxtrace_record *itr)
 489 {
 490         struct cs_etm_recording *ptr =
 491                         container_of(itr, struct cs_etm_recording, itr);
 492         struct perf_evsel *evsel;
 493
 494         evlist__for_each_entry(ptr->evlist, evsel) {
 495                 if (evsel->attr.type == ptr->cs_etm_pmu->type)
 496                         return perf_evsel__enable(evsel);
 497         }
 498         return -EINVAL;
 499 }
 500
 501 static u64 cs_etm_reference(struct auxtrace_record *itr __maybe_unused)
 502 {
 503         return (((u64) rand() <<  0) & 0x00000000FFFFFFFFull) |
 504                 (((u64) rand() << 32) & 0xFFFFFFFF00000000ull);
 505 }
 506
 507 static void cs_etm_recording_free(struct auxtrace_record *itr)
 508 {
 509         struct cs_etm_recording *ptr =
 510                         container_of(itr, struct cs_etm_recording, itr);
 511         free(ptr);
 512 }
 513
 514 static int cs_etm_read_finish(struct auxtrace_record *itr, int idx)
 515 {
 516         struct cs_etm_recording *ptr =
 517                         container_of(itr, struct cs_etm_recording, itr);
 518         struct perf_evsel *evsel;
 519
 520         evlist__for_each_entry(ptr->evlist, evsel) {
 521                 if (evsel->attr.type == ptr->cs_etm_pmu->type)
 522                         return perf_evlist__enable_event_idx(ptr->evlist,
 523                                                              evsel, idx);
 524         }
 525
 526         return -EINVAL;
 527 }
 528
 529 struct auxtrace_record *cs_etm_record_init(int *err)
 530 {
 531         struct perf_pmu *cs_etm_pmu;
 532         struct cs_etm_recording *ptr;
 533
 534         cs_etm_pmu = perf_pmu__find(CORESIGHT_ETM_PMU_NAME);
 535
 536         if (!cs_etm_pmu) {
 537                 *err = -EINVAL;
 538                 goto out;
 539         }
 540
 541         ptr = zalloc(sizeof(struct cs_etm_recording));
 542         if (!ptr) {
 543                 *err = -ENOMEM;
 544                 goto out;
 545         }
 546
 547         ptr->cs_etm_pmu                 = cs_etm_pmu;
 548         ptr->itr.parse_snapshot_options = cs_etm_parse_snapshot_options;
 549         ptr->itr.recording_options      = cs_etm_recording_options;
 550         ptr->itr.info_priv_size         = cs_etm_info_priv_size;
 551         ptr->itr.info_fill              = cs_etm_info_fill;
 552         ptr->itr.find_snapshot          = cs_etm_find_snapshot;
 553         ptr->itr.snapshot_start         = cs_etm_snapshot_start;
 554         ptr->itr.snapshot_finish        = cs_etm_snapshot_finish;
 555         ptr->itr.reference              = cs_etm_reference;
 556         ptr->itr.free                   = cs_etm_recording_free;
 557         ptr->itr.read_finish            = cs_etm_read_finish;
 558
 559         *err = 0;
 560         return &ptr->itr;
 561 out:
 562         return NULL;
 563 }
 564
 565 static FILE *cs_device__open_file(const char *name)
 566 {
 567         struct stat st;
 568         char path[PATH_MAX];
 569         const char *sysfs;
 570
 571         sysfs = sysfs__mountpoint();
 572         if (!sysfs)
 573                 return NULL;
 574
 575         snprintf(path, PATH_MAX,
 576                  "%s" CS_BUS_DEVICE_PATH "%s", sysfs, name);
 577
 578         printf("path: %s\n", path);
 579
 580         if (stat(path, &st) < 0)
 581                 return NULL;
 582
 583         return fopen(path, "w");
 584
 585 }
 586
 587 static __attribute__((format(printf, 2, 3)))
 588 int cs_device__print_file(const char *name, const char *fmt, ...)
 589 {
 590         va_list args;
 591         FILE *file;
 592         int ret = -EINVAL;
 593
 594         va_start(args, fmt);
 595         file = cs_device__open_file(name);
 596         if (file) {
 597                 ret = vfprintf(file, fmt, args);
 598                 fclose(file);
 599         }
 600         va_end(args);
 601         return ret;
 602 }
 603
 604 int cs_etm_set_drv_config(struct perf_evsel_config_term *term)
 605 {
 606         int ret;
 607         char enable_sink[ENABLE_SINK_MAX];
 608
 609         snprintf(enable_sink, ENABLE_SINK_MAX, "%s/%s",
 610                  term->val.drv_cfg, "enable_sink");
 611
 612         ret = cs_device__print_file(enable_sink, "%d", 1);
 613         if (ret < 0)
 614                 return ret;
 615
 616         return 0;
 617 }