tools/perf/util/thread.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <elf.h>
   3 #include <errno.h>
   4 #include <fcntl.h>
   5 #include <stdlib.h>
   6 #include <stdio.h>
   7 #include <string.h>
   8 #include <linux/kernel.h>
   9 #include <linux/zalloc.h>
  10 #include "dso.h"
  11 #include "session.h"
  12 #include "thread.h"
  13 #include "thread-stack.h"
  14 #include "debug.h"
  15 #include "namespaces.h"
  16 #include "comm.h"
  17 #include "map.h"
  18 #include "symbol.h"
  19 #include "unwind.h"
  20 #include "callchain.h"
  21 #include "dwarf-regs.h"
  22
  23 #include <api/fs/fs.h>
  24
  25 int thread__init_maps(struct thread *thread, struct machine *machine)
  26 {
  27         pid_t pid = thread__pid(thread);
  28
  29         if (pid == thread__tid(thread) || pid == -1) {
  30                 thread__set_maps(thread, maps__new(machine));
  31         } else {
  32                 struct thread *leader = machine__findnew_thread(machine, pid, pid);
  33
  34                 if (leader) {
  35                         thread__set_maps(thread, maps__get(thread__maps(leader)));
  36                         thread__put(leader);
  37                 }
  38         }
  39
  40         return thread__maps(thread) ? 0 : -1;
  41 }
  42
  43 struct thread *thread__new(pid_t pid, pid_t tid)
  44 {
  45         RC_STRUCT(thread) *_thread = zalloc(sizeof(*_thread));
  46         struct thread *thread;
  47
  48         if (ADD_RC_CHK(thread, _thread) != NULL) {
  49                 struct comm *comm;
  50                 char comm_str[32];
  51
  52                 thread__set_pid(thread, pid);
  53                 thread__set_tid(thread, tid);
  54                 thread__set_ppid(thread, -1);
  55                 thread__set_cpu(thread, -1);
  56                 thread__set_guest_cpu(thread, -1);
  57                 thread__set_e_machine(thread, EM_NONE);
  58                 thread__set_lbr_stitch_enable(thread, false);
  59                 INIT_LIST_HEAD(thread__namespaces_list(thread));
  60                 INIT_LIST_HEAD(thread__comm_list(thread));
  61                 init_rwsem(thread__namespaces_lock(thread));
  62                 init_rwsem(thread__comm_lock(thread));
  63
  64                 snprintf(comm_str, sizeof(comm_str), ":%d", tid);
  65                 comm = comm__new(comm_str, 0, false);
  66                 if (!comm)
  67                         goto err_thread;
  68
  69                 list_add(&comm->list, thread__comm_list(thread));
  70                 refcount_set(thread__refcnt(thread), 1);
  71                 /* Thread holds first ref to nsdata. */
  72                 RC_CHK_ACCESS(thread)->nsinfo = nsinfo__new(pid);
  73                 srccode_state_init(thread__srccode_state(thread));
  74         }
  75
  76         return thread;
  77
  78 err_thread:
  79         thread__delete(thread);
  80         return NULL;
  81 }
  82
  83 static void (*thread__priv_destructor)(void *priv);
  84
  85 void thread__set_priv_destructor(void (*destructor)(void *priv))
  86 {
  87         assert(thread__priv_destructor == NULL);
  88
  89         thread__priv_destructor = destructor;
  90 }
  91
  92 void thread__delete(struct thread *thread)
  93 {
  94         struct namespaces *namespaces, *tmp_namespaces;
  95         struct comm *comm, *tmp_comm;
  96
  97         thread_stack__free(thread);
  98
  99         if (thread__maps(thread)) {
 100                 maps__put(thread__maps(thread));
 101                 thread__set_maps(thread, NULL);
 102         }
 103         down_write(thread__namespaces_lock(thread));
 104         list_for_each_entry_safe(namespaces, tmp_namespaces,
 105                                  thread__namespaces_list(thread), list) {
 106                 list_del_init(&namespaces->list);
 107                 namespaces__free(namespaces);
 108         }
 109         up_write(thread__namespaces_lock(thread));
 110
 111         down_write(thread__comm_lock(thread));
 112         list_for_each_entry_safe(comm, tmp_comm, thread__comm_list(thread), list) {
 113                 list_del_init(&comm->list);
 114                 comm__free(comm);
 115         }
 116         up_write(thread__comm_lock(thread));
 117
 118         nsinfo__zput(RC_CHK_ACCESS(thread)->nsinfo);
 119         srccode_state_free(thread__srccode_state(thread));
 120
 121         exit_rwsem(thread__namespaces_lock(thread));
 122         exit_rwsem(thread__comm_lock(thread));
 123         thread__free_stitch_list(thread);
 124
 125         if (thread__priv_destructor)
 126                 thread__priv_destructor(thread__priv(thread));
 127
 128         RC_CHK_FREE(thread);
 129 }
 130
 131 struct thread *thread__get(struct thread *thread)
 132 {
 133         struct thread *result;
 134
 135         if (RC_CHK_GET(result, thread))
 136                 refcount_inc(thread__refcnt(thread));
 137
 138         return result;
 139 }
 140
 141 void thread__put(struct thread *thread)
 142 {
 143         if (thread && refcount_dec_and_test(thread__refcnt(thread)))
 144                 thread__delete(thread);
 145         else
 146                 RC_CHK_PUT(thread);
 147 }
 148
 149 static struct namespaces *__thread__namespaces(struct thread *thread)
 150 {
 151         if (list_empty(thread__namespaces_list(thread)))
 152                 return NULL;
 153
 154         return list_first_entry(thread__namespaces_list(thread), struct namespaces, list);
 155 }
 156
 157 struct namespaces *thread__namespaces(struct thread *thread)
 158 {
 159         struct namespaces *ns;
 160
 161         down_read(thread__namespaces_lock(thread));
 162         ns = __thread__namespaces(thread);
 163         up_read(thread__namespaces_lock(thread));
 164
 165         return ns;
 166 }
 167
 168 static int __thread__set_namespaces(struct thread *thread, u64 timestamp,
 169                                     struct perf_record_namespaces *event)
 170 {
 171         struct namespaces *new, *curr = __thread__namespaces(thread);
 172
 173         new = namespaces__new(event);
 174         if (!new)
 175                 return -ENOMEM;
 176
 177         list_add(&new->list, thread__namespaces_list(thread));
 178
 179         if (timestamp && curr) {
 180                 /*
 181                  * setns syscall must have changed few or all the namespaces
 182                  * of this thread. Update end time for the namespaces
 183                  * previously used.
 184                  */
 185                 curr = list_next_entry(new, list);
 186                 curr->end_time = timestamp;
 187         }
 188
 189         return 0;
 190 }
 191
 192 int thread__set_namespaces(struct thread *thread, u64 timestamp,
 193                            struct perf_record_namespaces *event)
 194 {
 195         int ret;
 196
 197         down_write(thread__namespaces_lock(thread));
 198         ret = __thread__set_namespaces(thread, timestamp, event);
 199         up_write(thread__namespaces_lock(thread));
 200         return ret;
 201 }
 202
 203 struct comm *thread__comm(struct thread *thread)
 204 {
 205         if (list_empty(thread__comm_list(thread)))
 206                 return NULL;
 207
 208         return list_first_entry(thread__comm_list(thread), struct comm, list);
 209 }
 210
 211 struct comm *thread__exec_comm(struct thread *thread)
 212 {
 213         struct comm *comm, *last = NULL, *second_last = NULL;
 214
 215         list_for_each_entry(comm, thread__comm_list(thread), list) {
 216                 if (comm->exec)
 217                         return comm;
 218                 second_last = last;
 219                 last = comm;
 220         }
 221
 222         /*
 223          * 'last' with no start time might be the parent's comm of a synthesized
 224          * thread (created by processing a synthesized fork event). For a main
 225          * thread, that is very probably wrong. Prefer a later comm to avoid
 226          * that case.
 227          */
 228         if (second_last && !last->start && thread__pid(thread) == thread__tid(thread))
 229                 return second_last;
 230
 231         return last;
 232 }
 233
 234 static int ____thread__set_comm(struct thread *thread, const char *str,
 235                                 u64 timestamp, bool exec)
 236 {
 237         struct comm *new, *curr = thread__comm(thread);
 238
 239         /* Override the default :tid entry */
 240         if (!thread__comm_set(thread)) {
 241                 int err = comm__override(curr, str, timestamp, exec);
 242                 if (err)
 243                         return err;
 244         } else {
 245                 new = comm__new(str, timestamp, exec);
 246                 if (!new)
 247                         return -ENOMEM;
 248                 list_add(&new->list, thread__comm_list(thread));
 249
 250                 if (exec)
 251                         unwind__flush_access(thread__maps(thread));
 252         }
 253
 254         thread__set_comm_set(thread, true);
 255
 256         return 0;
 257 }
 258
 259 int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,
 260                        bool exec)
 261 {
 262         int ret;
 263
 264         down_write(thread__comm_lock(thread));
 265         ret = ____thread__set_comm(thread, str, timestamp, exec);
 266         up_write(thread__comm_lock(thread));
 267         return ret;
 268 }
 269
 270 int thread__set_comm_from_proc(struct thread *thread)
 271 {
 272         char path[64];
 273         char *comm = NULL;
 274         size_t sz;
 275         int err = -1;
 276
 277         if (!(snprintf(path, sizeof(path), "%d/task/%d/comm",
 278                        thread__pid(thread), thread__tid(thread)) >= (int)sizeof(path)) &&
 279             procfs__read_str(path, &comm, &sz) == 0) {
 280                 comm[sz - 1] = '\0';
 281                 err = thread__set_comm(thread, comm, 0);
 282         }
 283
 284         return err;
 285 }
 286
 287 static const char *__thread__comm_str(struct thread *thread)
 288 {
 289         const struct comm *comm = thread__comm(thread);
 290
 291         if (!comm)
 292                 return NULL;
 293
 294         return comm__str(comm);
 295 }
 296
 297 const char *thread__comm_str(struct thread *thread)
 298 {
 299         const char *str;
 300
 301         down_read(thread__comm_lock(thread));
 302         str = __thread__comm_str(thread);
 303         up_read(thread__comm_lock(thread));
 304
 305         return str;
 306 }
 307
 308 static int __thread__comm_len(struct thread *thread, const char *comm)
 309 {
 310         if (!comm)
 311                 return 0;
 312         thread__set_comm_len(thread, strlen(comm));
 313
 314         return thread__var_comm_len(thread);
 315 }
 316
 317 /* CHECKME: it should probably better return the max comm len from its comm list */
 318 int thread__comm_len(struct thread *thread)
 319 {
 320         int comm_len = thread__var_comm_len(thread);
 321
 322         if (!comm_len) {
 323                 const char *comm;
 324
 325                 down_read(thread__comm_lock(thread));
 326                 comm = __thread__comm_str(thread);
 327                 comm_len = __thread__comm_len(thread, comm);
 328                 up_read(thread__comm_lock(thread));
 329         }
 330
 331         return comm_len;
 332 }
 333
 334 size_t thread__fprintf(struct thread *thread, FILE *fp)
 335 {
 336         return fprintf(fp, "Thread %d %s\n", thread__tid(thread), thread__comm_str(thread)) +
 337                maps__fprintf(thread__maps(thread), fp);
 338 }
 339
 340 int thread__insert_map(struct thread *thread, struct map *map)
 341 {
 342         int ret;
 343
 344         ret = unwind__prepare_access(thread__maps(thread), map, NULL);
 345         if (ret)
 346                 return ret;
 347
 348         return maps__fixup_overlap_and_insert(thread__maps(thread), map);
 349 }
 350
 351 struct thread__prepare_access_maps_cb_args {
 352         int err;
 353         struct maps *maps;
 354 };
 355
 356 static int thread__prepare_access_maps_cb(struct map *map, void *data)
 357 {
 358         bool initialized = false;
 359         struct thread__prepare_access_maps_cb_args *args = data;
 360
 361         args->err = unwind__prepare_access(args->maps, map, &initialized);
 362
 363         return (args->err || initialized) ? 1 : 0;
 364 }
 365
 366 static int thread__prepare_access(struct thread *thread)
 367 {
 368         struct thread__prepare_access_maps_cb_args args = {
 369                 .err = 0,
 370         };
 371
 372         if (dwarf_callchain_users) {
 373                 args.maps = thread__maps(thread);
 374                 maps__for_each_map(thread__maps(thread), thread__prepare_access_maps_cb, &args);
 375         }
 376
 377         return args.err;
 378 }
 379
 380 static int thread__clone_maps(struct thread *thread, struct thread *parent, bool do_maps_clone)
 381 {
 382         /* This is new thread, we share map groups for process. */
 383         if (thread__pid(thread) == thread__pid(parent))
 384                 return thread__prepare_access(thread);
 385
 386         if (maps__equal(thread__maps(thread), thread__maps(parent))) {
 387                 pr_debug("broken map groups on thread %d/%d parent %d/%d\n",
 388                          thread__pid(thread), thread__tid(thread),
 389                          thread__pid(parent), thread__tid(parent));
 390                 return 0;
 391         }
 392         /* But this one is new process, copy maps. */
 393         return do_maps_clone ? maps__copy_from(thread__maps(thread), thread__maps(parent)) : 0;
 394 }
 395
 396 int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp, bool do_maps_clone)
 397 {
 398         if (thread__comm_set(parent)) {
 399                 const char *comm = thread__comm_str(parent);
 400                 int err;
 401                 if (!comm)
 402                         return -ENOMEM;
 403                 err = thread__set_comm(thread, comm, timestamp);
 404                 if (err)
 405                         return err;
 406         }
 407
 408         thread__set_ppid(thread, thread__tid(parent));
 409         return thread__clone_maps(thread, parent, do_maps_clone);
 410 }
 411
 412 void thread__find_cpumode_addr_location(struct thread *thread, u64 addr,
 413                                         bool symbols, struct addr_location *al)
 414 {
 415         size_t i;
 416         const u8 cpumodes[] = {
 417                 PERF_RECORD_MISC_USER,
 418                 PERF_RECORD_MISC_KERNEL,
 419                 PERF_RECORD_MISC_GUEST_USER,
 420                 PERF_RECORD_MISC_GUEST_KERNEL
 421         };
 422
 423         for (i = 0; i < ARRAY_SIZE(cpumodes); i++) {
 424                 if (symbols)
 425                         thread__find_symbol(thread, cpumodes[i], addr, al);
 426                 else
 427                         thread__find_map(thread, cpumodes[i], addr, al);
 428
 429                 if (al->map)
 430                         break;
 431         }
 432 }
 433
 434 static uint16_t read_proc_e_machine_for_pid(pid_t pid)
 435 {
 436         char path[6 /* "/proc/" */ + 11 /* max length of pid */ + 5 /* "/exe\0" */];
 437         int fd;
 438         uint16_t e_machine = EM_NONE;
 439
 440         snprintf(path, sizeof(path), "/proc/%d/exe", pid);
 441         fd = open(path, O_RDONLY);
 442         if (fd >= 0) {
 443                 _Static_assert(offsetof(Elf32_Ehdr, e_machine) == 18, "Unexpected offset");
 444                 _Static_assert(offsetof(Elf64_Ehdr, e_machine) == 18, "Unexpected offset");
 445                 if (pread(fd, &e_machine, sizeof(e_machine), 18) != sizeof(e_machine))
 446                         e_machine = EM_NONE;
 447                 close(fd);
 448         }
 449         return e_machine;
 450 }
 451
 452 static int thread__e_machine_callback(struct map *map, void *machine)
 453 {
 454         struct dso *dso = map__dso(map);
 455
 456         _Static_assert(0 == EM_NONE, "Unexpected EM_NONE");
 457         if (!dso)
 458                 return EM_NONE;
 459
 460         return dso__e_machine(dso, machine);
 461 }
 462
 463 uint16_t thread__e_machine(struct thread *thread, struct machine *machine)
 464 {
 465         pid_t tid, pid;
 466         uint16_t e_machine = RC_CHK_ACCESS(thread)->e_machine;
 467
 468         if (e_machine != EM_NONE)
 469                 return e_machine;
 470
 471         tid = thread__tid(thread);
 472         pid = thread__pid(thread);
 473         if (pid != tid) {
 474                 struct thread *parent = machine__findnew_thread(machine, pid, pid);
 475
 476                 if (parent) {
 477                         e_machine = thread__e_machine(parent, machine);
 478                         thread__put(parent);
 479                         thread__set_e_machine(thread, e_machine);
 480                         return e_machine;
 481                 }
 482                 /* Something went wrong, fallback. */
 483         }
 484         /* Reading on the PID thread. First try to find from the maps. */
 485         e_machine = maps__for_each_map(thread__maps(thread),
 486                                        thread__e_machine_callback,
 487                                        machine);
 488         if (e_machine == EM_NONE) {
 489                 /* Maps failed, perhaps we're live with map events disabled. */
 490                 bool is_live = machine->machines == NULL;
 491
 492                 if (!is_live) {
 493                         /* Check if the session has a data file. */
 494                         struct perf_session *session = container_of(machine->machines,
 495                                                                     struct perf_session,
 496                                                                     machines);
 497
 498                         is_live = !!session->data;
 499                 }
 500                 /* Read from /proc/pid/exe if live. */
 501                 if (is_live)
 502                         e_machine = read_proc_e_machine_for_pid(pid);
 503         }
 504         if (e_machine != EM_NONE)
 505                 thread__set_e_machine(thread, e_machine);
 506         else
 507                 e_machine = EM_HOST;
 508         return e_machine;
 509 }
 510
 511 struct thread *thread__main_thread(struct machine *machine, struct thread *thread)
 512 {
 513         if (thread__pid(thread) == thread__tid(thread))
 514                 return thread__get(thread);
 515
 516         if (thread__pid(thread) == -1)
 517                 return NULL;
 518
 519         return machine__find_thread(machine, thread__pid(thread), thread__pid(thread));
 520 }
 521
 522 int thread__memcpy(struct thread *thread, struct machine *machine,
 523                    void *buf, u64 ip, int len, bool *is64bit)
 524 {
 525         u8 cpumode = PERF_RECORD_MISC_USER;
 526         struct addr_location al;
 527         struct dso *dso;
 528         long offset;
 529
 530         if (machine__kernel_ip(machine, ip))
 531                 cpumode = PERF_RECORD_MISC_KERNEL;
 532
 533         addr_location__init(&al);
 534         if (!thread__find_map(thread, cpumode, ip, &al)) {
 535                 addr_location__exit(&al);
 536                 return -1;
 537         }
 538
 539         dso = map__dso(al.map);
 540
 541         if (!dso || dso__data(dso)->status == DSO_DATA_STATUS_ERROR || map__load(al.map) < 0) {
 542                 addr_location__exit(&al);
 543                 return -1;
 544         }
 545
 546         offset = map__map_ip(al.map, ip);
 547         if (is64bit)
 548                 *is64bit = dso__is_64_bit(dso);
 549
 550         addr_location__exit(&al);
 551
 552         return dso__data_read_offset(dso, machine, offset, buf, len);
 553 }
 554
 555 void thread__free_stitch_list(struct thread *thread)
 556 {
 557         struct lbr_stitch *lbr_stitch = thread__lbr_stitch(thread);
 558         struct stitch_list *pos, *tmp;
 559
 560         if (!lbr_stitch)
 561                 return;
 562
 563         list_for_each_entry_safe(pos, tmp, &lbr_stitch->lists, node) {
 564                 map_symbol__exit(&pos->cursor.ms);
 565                 list_del_init(&pos->node);
 566                 free(pos);
 567         }
 568
 569         list_for_each_entry_safe(pos, tmp, &lbr_stitch->free_lists, node) {
 570                 list_del_init(&pos->node);
 571                 free(pos);
 572         }
 573
 574         for (unsigned int i = 0 ; i < lbr_stitch->prev_lbr_cursor_size; i++)
 575                 map_symbol__exit(&lbr_stitch->prev_lbr_cursor[i].ms);
 576
 577         zfree(&lbr_stitch->prev_lbr_cursor);
 578         free(thread__lbr_stitch(thread));
 579         thread__set_lbr_stitch(thread, NULL);
 580 }