tools/perf/util/thread.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <errno.h>
   3 #include <stdlib.h>
   4 #include <stdio.h>
   5 #include <string.h>
   6 #include <linux/kernel.h>
   7 #include <linux/zalloc.h>
   8 #include "dso.h"
   9 #include "session.h"
  10 #include "thread.h"
  11 #include "thread-stack.h"
  12 #include "debug.h"
  13 #include "namespaces.h"
  14 #include "comm.h"
  15 #include "map.h"
  16 #include "symbol.h"
  17 #include "unwind.h"
  18 #include "callchain.h"
  19
  20 #include <api/fs/fs.h>
  21
  22 int thread__init_maps(struct thread *thread, struct machine *machine)
  23 {
  24         pid_t pid = thread__pid(thread);
  25
  26         if (pid == thread__tid(thread) || pid == -1) {
  27                 thread__set_maps(thread, maps__new(machine));
  28         } else {
  29                 struct thread *leader = __machine__findnew_thread(machine, pid, pid);
  30
  31                 if (leader) {
  32                         thread__set_maps(thread, maps__get(thread__maps(leader)));
  33                         thread__put(leader);
  34                 }
  35         }
  36
  37         return thread__maps(thread) ? 0 : -1;
  38 }
  39
  40 struct thread *thread__new(pid_t pid, pid_t tid)
  41 {
  42         char *comm_str;
  43         struct comm *comm;
  44         RC_STRUCT(thread) *_thread = zalloc(sizeof(*_thread));
  45         struct thread *thread;
  46
  47         if (ADD_RC_CHK(thread, _thread) != NULL) {
  48                 thread__set_pid(thread, pid);
  49                 thread__set_tid(thread, tid);
  50                 thread__set_ppid(thread, -1);
  51                 thread__set_cpu(thread, -1);
  52                 thread__set_guest_cpu(thread, -1);
  53                 thread__set_lbr_stitch_enable(thread, false);
  54                 INIT_LIST_HEAD(thread__namespaces_list(thread));
  55                 INIT_LIST_HEAD(thread__comm_list(thread));
  56                 init_rwsem(thread__namespaces_lock(thread));
  57                 init_rwsem(thread__comm_lock(thread));
  58
  59                 comm_str = malloc(32);
  60                 if (!comm_str)
  61                         goto err_thread;
  62
  63                 snprintf(comm_str, 32, ":%d", tid);
  64                 comm = comm__new(comm_str, 0, false);
  65                 free(comm_str);
  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         free(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         maps__fixup_overlappings(thread__maps(thread), map, stderr);
 349         return maps__insert(thread__maps(thread), map);
 350 }
 351
 352 static int __thread__prepare_access(struct thread *thread)
 353 {
 354         bool initialized = false;
 355         int err = 0;
 356         struct maps *maps = thread__maps(thread);
 357         struct map_rb_node *rb_node;
 358
 359         down_read(maps__lock(maps));
 360
 361         maps__for_each_entry(maps, rb_node) {
 362                 err = unwind__prepare_access(thread__maps(thread), rb_node->map, &initialized);
 363                 if (err || initialized)
 364                         break;
 365         }
 366
 367         up_read(maps__lock(maps));
 368
 369         return err;
 370 }
 371
 372 static int thread__prepare_access(struct thread *thread)
 373 {
 374         int err = 0;
 375
 376         if (dwarf_callchain_users)
 377                 err = __thread__prepare_access(thread);
 378
 379         return err;
 380 }
 381
 382 static int thread__clone_maps(struct thread *thread, struct thread *parent, bool do_maps_clone)
 383 {
 384         /* This is new thread, we share map groups for process. */
 385         if (thread__pid(thread) == thread__pid(parent))
 386                 return thread__prepare_access(thread);
 387
 388         if (thread__maps(thread) == thread__maps(parent)) {
 389                 pr_debug("broken map groups on thread %d/%d parent %d/%d\n",
 390                          thread__pid(thread), thread__tid(thread),
 391                          thread__pid(parent), thread__tid(parent));
 392                 return 0;
 393         }
 394         /* But this one is new process, copy maps. */
 395         return do_maps_clone ? maps__clone(thread, thread__maps(parent)) : 0;
 396 }
 397
 398 int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp, bool do_maps_clone)
 399 {
 400         if (thread__comm_set(parent)) {
 401                 const char *comm = thread__comm_str(parent);
 402                 int err;
 403                 if (!comm)
 404                         return -ENOMEM;
 405                 err = thread__set_comm(thread, comm, timestamp);
 406                 if (err)
 407                         return err;
 408         }
 409
 410         thread__set_ppid(thread, thread__tid(parent));
 411         return thread__clone_maps(thread, parent, do_maps_clone);
 412 }
 413
 414 void thread__find_cpumode_addr_location(struct thread *thread, u64 addr,
 415                                         struct addr_location *al)
 416 {
 417         size_t i;
 418         const u8 cpumodes[] = {
 419                 PERF_RECORD_MISC_USER,
 420                 PERF_RECORD_MISC_KERNEL,
 421                 PERF_RECORD_MISC_GUEST_USER,
 422                 PERF_RECORD_MISC_GUEST_KERNEL
 423         };
 424
 425         for (i = 0; i < ARRAY_SIZE(cpumodes); i++) {
 426                 thread__find_symbol(thread, cpumodes[i], addr, al);
 427                 if (al->map)
 428                         break;
 429         }
 430 }
 431
 432 struct thread *thread__main_thread(struct machine *machine, struct thread *thread)
 433 {
 434         if (thread__pid(thread) == thread__tid(thread))
 435                 return thread__get(thread);
 436
 437         if (thread__pid(thread) == -1)
 438                 return NULL;
 439
 440         return machine__find_thread(machine, thread__pid(thread), thread__pid(thread));
 441 }
 442
 443 int thread__memcpy(struct thread *thread, struct machine *machine,
 444                    void *buf, u64 ip, int len, bool *is64bit)
 445 {
 446         u8 cpumode = PERF_RECORD_MISC_USER;
 447         struct addr_location al;
 448         struct dso *dso;
 449         long offset;
 450
 451         if (machine__kernel_ip(machine, ip))
 452                 cpumode = PERF_RECORD_MISC_KERNEL;
 453
 454         addr_location__init(&al);
 455         if (!thread__find_map(thread, cpumode, ip, &al)) {
 456                 addr_location__exit(&al);
 457                 return -1;
 458         }
 459
 460         dso = map__dso(al.map);
 461
 462         if (!dso || dso->data.status == DSO_DATA_STATUS_ERROR || map__load(al.map) < 0) {
 463                 addr_location__exit(&al);
 464                 return -1;
 465         }
 466
 467         offset = map__map_ip(al.map, ip);
 468         if (is64bit)
 469                 *is64bit = dso->is_64_bit;
 470
 471         addr_location__exit(&al);
 472
 473         return dso__data_read_offset(dso, machine, offset, buf, len);
 474 }
 475
 476 void thread__free_stitch_list(struct thread *thread)
 477 {
 478         struct lbr_stitch *lbr_stitch = thread__lbr_stitch(thread);
 479         struct stitch_list *pos, *tmp;
 480
 481         if (!lbr_stitch)
 482                 return;
 483
 484         list_for_each_entry_safe(pos, tmp, &lbr_stitch->lists, node) {
 485                 list_del_init(&pos->node);
 486                 free(pos);
 487         }
 488
 489         list_for_each_entry_safe(pos, tmp, &lbr_stitch->free_lists, node) {
 490                 list_del_init(&pos->node);
 491                 free(pos);
 492         }
 493
 494         zfree(&lbr_stitch->prev_lbr_cursor);
 495         free(thread__lbr_stitch(thread));
 496         thread__set_lbr_stitch(thread, NULL);
 497 }