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         RC_STRUCT(thread) *_thread = zalloc(sizeof(*_thread));
  43         struct thread *thread;
  44
  45         if (ADD_RC_CHK(thread, _thread) != NULL) {
  46                 struct comm *comm;
  47                 char comm_str[32];
  48
  49                 thread__set_pid(thread, pid);
  50                 thread__set_tid(thread, tid);
  51                 thread__set_ppid(thread, -1);
  52                 thread__set_cpu(thread, -1);
  53                 thread__set_guest_cpu(thread, -1);
  54                 thread__set_lbr_stitch_enable(thread, false);
  55                 INIT_LIST_HEAD(thread__namespaces_list(thread));
  56                 INIT_LIST_HEAD(thread__comm_list(thread));
  57                 init_rwsem(thread__namespaces_lock(thread));
  58                 init_rwsem(thread__comm_lock(thread));
  59
  60                 snprintf(comm_str, sizeof(comm_str), ":%d", tid);
  61                 comm = comm__new(comm_str, 0, false);
  62                 if (!comm)
  63                         goto err_thread;
  64
  65                 list_add(&comm->list, thread__comm_list(thread));
  66                 refcount_set(thread__refcnt(thread), 1);
  67                 /* Thread holds first ref to nsdata. */
  68                 RC_CHK_ACCESS(thread)->nsinfo = nsinfo__new(pid);
  69                 srccode_state_init(thread__srccode_state(thread));
  70         }
  71
  72         return thread;
  73
  74 err_thread:
  75         thread__delete(thread);
  76         return NULL;
  77 }
  78
  79 static void (*thread__priv_destructor)(void *priv);
  80
  81 void thread__set_priv_destructor(void (*destructor)(void *priv))
  82 {
  83         assert(thread__priv_destructor == NULL);
  84
  85         thread__priv_destructor = destructor;
  86 }
  87
  88 void thread__delete(struct thread *thread)
  89 {
  90         struct namespaces *namespaces, *tmp_namespaces;
  91         struct comm *comm, *tmp_comm;
  92
  93         thread_stack__free(thread);
  94
  95         if (thread__maps(thread)) {
  96                 maps__put(thread__maps(thread));
  97                 thread__set_maps(thread, NULL);
  98         }
  99         down_write(thread__namespaces_lock(thread));
 100         list_for_each_entry_safe(namespaces, tmp_namespaces,
 101                                  thread__namespaces_list(thread), list) {
 102                 list_del_init(&namespaces->list);
 103                 namespaces__free(namespaces);
 104         }
 105         up_write(thread__namespaces_lock(thread));
 106
 107         down_write(thread__comm_lock(thread));
 108         list_for_each_entry_safe(comm, tmp_comm, thread__comm_list(thread), list) {
 109                 list_del_init(&comm->list);
 110                 comm__free(comm);
 111         }
 112         up_write(thread__comm_lock(thread));
 113
 114         nsinfo__zput(RC_CHK_ACCESS(thread)->nsinfo);
 115         srccode_state_free(thread__srccode_state(thread));
 116
 117         exit_rwsem(thread__namespaces_lock(thread));
 118         exit_rwsem(thread__comm_lock(thread));
 119         thread__free_stitch_list(thread);
 120
 121         if (thread__priv_destructor)
 122                 thread__priv_destructor(thread__priv(thread));
 123
 124         RC_CHK_FREE(thread);
 125 }
 126
 127 struct thread *thread__get(struct thread *thread)
 128 {
 129         struct thread *result;
 130
 131         if (RC_CHK_GET(result, thread))
 132                 refcount_inc(thread__refcnt(thread));
 133
 134         return result;
 135 }
 136
 137 void thread__put(struct thread *thread)
 138 {
 139         if (thread && refcount_dec_and_test(thread__refcnt(thread)))
 140                 thread__delete(thread);
 141         else
 142                 RC_CHK_PUT(thread);
 143 }
 144
 145 static struct namespaces *__thread__namespaces(struct thread *thread)
 146 {
 147         if (list_empty(thread__namespaces_list(thread)))
 148                 return NULL;
 149
 150         return list_first_entry(thread__namespaces_list(thread), struct namespaces, list);
 151 }
 152
 153 struct namespaces *thread__namespaces(struct thread *thread)
 154 {
 155         struct namespaces *ns;
 156
 157         down_read(thread__namespaces_lock(thread));
 158         ns = __thread__namespaces(thread);
 159         up_read(thread__namespaces_lock(thread));
 160
 161         return ns;
 162 }
 163
 164 static int __thread__set_namespaces(struct thread *thread, u64 timestamp,
 165                                     struct perf_record_namespaces *event)
 166 {
 167         struct namespaces *new, *curr = __thread__namespaces(thread);
 168
 169         new = namespaces__new(event);
 170         if (!new)
 171                 return -ENOMEM;
 172
 173         list_add(&new->list, thread__namespaces_list(thread));
 174
 175         if (timestamp && curr) {
 176                 /*
 177                  * setns syscall must have changed few or all the namespaces
 178                  * of this thread. Update end time for the namespaces
 179                  * previously used.
 180                  */
 181                 curr = list_next_entry(new, list);
 182                 curr->end_time = timestamp;
 183         }
 184
 185         return 0;
 186 }
 187
 188 int thread__set_namespaces(struct thread *thread, u64 timestamp,
 189                            struct perf_record_namespaces *event)
 190 {
 191         int ret;
 192
 193         down_write(thread__namespaces_lock(thread));
 194         ret = __thread__set_namespaces(thread, timestamp, event);
 195         up_write(thread__namespaces_lock(thread));
 196         return ret;
 197 }
 198
 199 struct comm *thread__comm(struct thread *thread)
 200 {
 201         if (list_empty(thread__comm_list(thread)))
 202                 return NULL;
 203
 204         return list_first_entry(thread__comm_list(thread), struct comm, list);
 205 }
 206
 207 struct comm *thread__exec_comm(struct thread *thread)
 208 {
 209         struct comm *comm, *last = NULL, *second_last = NULL;
 210
 211         list_for_each_entry(comm, thread__comm_list(thread), list) {
 212                 if (comm->exec)
 213                         return comm;
 214                 second_last = last;
 215                 last = comm;
 216         }
 217
 218         /*
 219          * 'last' with no start time might be the parent's comm of a synthesized
 220          * thread (created by processing a synthesized fork event). For a main
 221          * thread, that is very probably wrong. Prefer a later comm to avoid
 222          * that case.
 223          */
 224         if (second_last && !last->start && thread__pid(thread) == thread__tid(thread))
 225                 return second_last;
 226
 227         return last;
 228 }
 229
 230 static int ____thread__set_comm(struct thread *thread, const char *str,
 231                                 u64 timestamp, bool exec)
 232 {
 233         struct comm *new, *curr = thread__comm(thread);
 234
 235         /* Override the default :tid entry */
 236         if (!thread__comm_set(thread)) {
 237                 int err = comm__override(curr, str, timestamp, exec);
 238                 if (err)
 239                         return err;
 240         } else {
 241                 new = comm__new(str, timestamp, exec);
 242                 if (!new)
 243                         return -ENOMEM;
 244                 list_add(&new->list, thread__comm_list(thread));
 245
 246                 if (exec)
 247                         unwind__flush_access(thread__maps(thread));
 248         }
 249
 250         thread__set_comm_set(thread, true);
 251
 252         return 0;
 253 }
 254
 255 int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,
 256                        bool exec)
 257 {
 258         int ret;
 259
 260         down_write(thread__comm_lock(thread));
 261         ret = ____thread__set_comm(thread, str, timestamp, exec);
 262         up_write(thread__comm_lock(thread));
 263         return ret;
 264 }
 265
 266 int thread__set_comm_from_proc(struct thread *thread)
 267 {
 268         char path[64];
 269         char *comm = NULL;
 270         size_t sz;
 271         int err = -1;
 272
 273         if (!(snprintf(path, sizeof(path), "%d/task/%d/comm",
 274                        thread__pid(thread), thread__tid(thread)) >= (int)sizeof(path)) &&
 275             procfs__read_str(path, &comm, &sz) == 0) {
 276                 comm[sz - 1] = '\0';
 277                 err = thread__set_comm(thread, comm, 0);
 278         }
 279
 280         return err;
 281 }
 282
 283 static const char *__thread__comm_str(struct thread *thread)
 284 {
 285         const struct comm *comm = thread__comm(thread);
 286
 287         if (!comm)
 288                 return NULL;
 289
 290         return comm__str(comm);
 291 }
 292
 293 const char *thread__comm_str(struct thread *thread)
 294 {
 295         const char *str;
 296
 297         down_read(thread__comm_lock(thread));
 298         str = __thread__comm_str(thread);
 299         up_read(thread__comm_lock(thread));
 300
 301         return str;
 302 }
 303
 304 static int __thread__comm_len(struct thread *thread, const char *comm)
 305 {
 306         if (!comm)
 307                 return 0;
 308         thread__set_comm_len(thread, strlen(comm));
 309
 310         return thread__var_comm_len(thread);
 311 }
 312
 313 /* CHECKME: it should probably better return the max comm len from its comm list */
 314 int thread__comm_len(struct thread *thread)
 315 {
 316         int comm_len = thread__var_comm_len(thread);
 317
 318         if (!comm_len) {
 319                 const char *comm;
 320
 321                 down_read(thread__comm_lock(thread));
 322                 comm = __thread__comm_str(thread);
 323                 comm_len = __thread__comm_len(thread, comm);
 324                 up_read(thread__comm_lock(thread));
 325         }
 326
 327         return comm_len;
 328 }
 329
 330 size_t thread__fprintf(struct thread *thread, FILE *fp)
 331 {
 332         return fprintf(fp, "Thread %d %s\n", thread__tid(thread), thread__comm_str(thread)) +
 333                maps__fprintf(thread__maps(thread), fp);
 334 }
 335
 336 int thread__insert_map(struct thread *thread, struct map *map)
 337 {
 338         int ret;
 339
 340         ret = unwind__prepare_access(thread__maps(thread), map, NULL);
 341         if (ret)
 342                 return ret;
 343
 344         return maps__fixup_overlap_and_insert(thread__maps(thread), map);
 345 }
 346
 347 struct thread__prepare_access_maps_cb_args {
 348         int err;
 349         struct maps *maps;
 350 };
 351
 352 static int thread__prepare_access_maps_cb(struct map *map, void *data)
 353 {
 354         bool initialized = false;
 355         struct thread__prepare_access_maps_cb_args *args = data;
 356
 357         args->err = unwind__prepare_access(args->maps, map, &initialized);
 358
 359         return (args->err || initialized) ? 1 : 0;
 360 }
 361
 362 static int thread__prepare_access(struct thread *thread)
 363 {
 364         struct thread__prepare_access_maps_cb_args args = {
 365                 .err = 0,
 366         };
 367
 368         if (dwarf_callchain_users) {
 369                 args.maps = thread__maps(thread);
 370                 maps__for_each_map(thread__maps(thread), thread__prepare_access_maps_cb, &args);
 371         }
 372
 373         return args.err;
 374 }
 375
 376 static int thread__clone_maps(struct thread *thread, struct thread *parent, bool do_maps_clone)
 377 {
 378         /* This is new thread, we share map groups for process. */
 379         if (thread__pid(thread) == thread__pid(parent))
 380                 return thread__prepare_access(thread);
 381
 382         if (maps__equal(thread__maps(thread), thread__maps(parent))) {
 383                 pr_debug("broken map groups on thread %d/%d parent %d/%d\n",
 384                          thread__pid(thread), thread__tid(thread),
 385                          thread__pid(parent), thread__tid(parent));
 386                 return 0;
 387         }
 388         /* But this one is new process, copy maps. */
 389         return do_maps_clone ? maps__copy_from(thread__maps(thread), thread__maps(parent)) : 0;
 390 }
 391
 392 int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp, bool do_maps_clone)
 393 {
 394         if (thread__comm_set(parent)) {
 395                 const char *comm = thread__comm_str(parent);
 396                 int err;
 397                 if (!comm)
 398                         return -ENOMEM;
 399                 err = thread__set_comm(thread, comm, timestamp);
 400                 if (err)
 401                         return err;
 402         }
 403
 404         thread__set_ppid(thread, thread__tid(parent));
 405         return thread__clone_maps(thread, parent, do_maps_clone);
 406 }
 407
 408 void thread__find_cpumode_addr_location(struct thread *thread, u64 addr,
 409                                         struct addr_location *al)
 410 {
 411         size_t i;
 412         const u8 cpumodes[] = {
 413                 PERF_RECORD_MISC_USER,
 414                 PERF_RECORD_MISC_KERNEL,
 415                 PERF_RECORD_MISC_GUEST_USER,
 416                 PERF_RECORD_MISC_GUEST_KERNEL
 417         };
 418
 419         for (i = 0; i < ARRAY_SIZE(cpumodes); i++) {
 420                 thread__find_symbol(thread, cpumodes[i], addr, al);
 421                 if (al->map)
 422                         break;
 423         }
 424 }
 425
 426 struct thread *thread__main_thread(struct machine *machine, struct thread *thread)
 427 {
 428         if (thread__pid(thread) == thread__tid(thread))
 429                 return thread__get(thread);
 430
 431         if (thread__pid(thread) == -1)
 432                 return NULL;
 433
 434         return machine__find_thread(machine, thread__pid(thread), thread__pid(thread));
 435 }
 436
 437 int thread__memcpy(struct thread *thread, struct machine *machine,
 438                    void *buf, u64 ip, int len, bool *is64bit)
 439 {
 440         u8 cpumode = PERF_RECORD_MISC_USER;
 441         struct addr_location al;
 442         struct dso *dso;
 443         long offset;
 444
 445         if (machine__kernel_ip(machine, ip))
 446                 cpumode = PERF_RECORD_MISC_KERNEL;
 447
 448         addr_location__init(&al);
 449         if (!thread__find_map(thread, cpumode, ip, &al)) {
 450                 addr_location__exit(&al);
 451                 return -1;
 452         }
 453
 454         dso = map__dso(al.map);
 455
 456         if (!dso || dso__data(dso)->status == DSO_DATA_STATUS_ERROR || map__load(al.map) < 0) {
 457                 addr_location__exit(&al);
 458                 return -1;
 459         }
 460
 461         offset = map__map_ip(al.map, ip);
 462         if (is64bit)
 463                 *is64bit = dso__is_64_bit(dso);
 464
 465         addr_location__exit(&al);
 466
 467         return dso__data_read_offset(dso, machine, offset, buf, len);
 468 }
 469
 470 void thread__free_stitch_list(struct thread *thread)
 471 {
 472         struct lbr_stitch *lbr_stitch = thread__lbr_stitch(thread);
 473         struct stitch_list *pos, *tmp;
 474
 475         if (!lbr_stitch)
 476                 return;
 477
 478         list_for_each_entry_safe(pos, tmp, &lbr_stitch->lists, node) {
 479                 map_symbol__exit(&pos->cursor.ms);
 480                 list_del_init(&pos->node);
 481                 free(pos);
 482         }
 483
 484         list_for_each_entry_safe(pos, tmp, &lbr_stitch->free_lists, node) {
 485                 list_del_init(&pos->node);
 486                 free(pos);
 487         }
 488
 489         for (unsigned int i = 0 ; i < lbr_stitch->prev_lbr_cursor_size; i++)
 490                 map_symbol__exit(&lbr_stitch->prev_lbr_cursor[i].ms);
 491
 492         zfree(&lbr_stitch->prev_lbr_cursor);
 493         free(thread__lbr_stitch(thread));
 494         thread__set_lbr_stitch(thread, NULL);
 495 }