projects/linux·blob master · refs

638 lines · 15.9 KiB

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
25int 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
43struct thread *thread__new(pid_t pid, pid_t tid)
44 NO_THREAD_SAFETY_ANALYSIS /* Allocation/creation is inherently single threaded. */
45{
46 RC_STRUCT(thread) *_thread = zalloc(sizeof(*_thread));
47 struct thread *thread;
48
49 if (ADD_RC_CHK(thread, _thread) != NULL) {
50 struct comm *comm;
51 char comm_str[32];
52
53 thread__set_pid(thread, pid);
54 thread__set_tid(thread, tid);
55 thread__set_ppid(thread, -1);
56 thread__set_cpu(thread, -1);
57 thread__set_guest_cpu(thread, -1);
58 thread__set_e_machine(thread, EM_NONE);
59 thread__set_e_is_big_endian(thread, false);
60 thread__set_lbr_stitch_enable(thread, false);
61 INIT_LIST_HEAD(thread__namespaces_list(thread));
62 INIT_LIST_HEAD(thread__comm_list(thread));
63 init_rwsem(thread__namespaces_lock(thread));
64 init_rwsem(thread__comm_lock(thread));
65
66 snprintf(comm_str, sizeof(comm_str), ":%d", tid);
67 comm = comm__new(comm_str, 0, false);
68 if (!comm)
69 goto err_thread;
70
71 list_add(&comm->list, thread__comm_list(thread));
72 refcount_set(thread__refcnt(thread), 1);
73 /* Thread holds first ref to nsdata. */
74 RC_CHK_ACCESS(thread)->nsinfo = nsinfo__new(pid);
75 srccode_state_init(thread__srccode_state(thread));
76 }
77
78 return thread;
79
80err_thread:
81 thread__delete(thread);
82 return NULL;
83}
84
85static void (*thread__priv_destructor)(void *priv);
86
87void thread__set_priv_destructor(void (*destructor)(void *priv))
88{
89 assert(thread__priv_destructor == NULL);
90
91 thread__priv_destructor = destructor;
92}
93
94void thread__delete(struct thread *thread)
95{
96 struct namespaces *namespaces, *tmp_namespaces;
97 struct comm *comm, *tmp_comm;
98
99 thread_stack__free(thread);
100
101 if (thread__maps(thread)) {
102 maps__put(thread__maps(thread));
103 thread__set_maps(thread, NULL);
104 }
105 down_write(thread__namespaces_lock(thread));
106 list_for_each_entry_safe(namespaces, tmp_namespaces,
107 thread__namespaces_list(thread), list) {
108 list_del_init(&namespaces->list);
109 namespaces__free(namespaces);
110 }
111 up_write(thread__namespaces_lock(thread));
112
113 down_write(thread__comm_lock(thread));
114 list_for_each_entry_safe(comm, tmp_comm, thread__comm_list(thread), list) {
115 list_del_init(&comm->list);
116 comm__free(comm);
117 }
118 up_write(thread__comm_lock(thread));
119
120 nsinfo__zput(RC_CHK_ACCESS(thread)->nsinfo);
121 srccode_state_free(thread__srccode_state(thread));
122
123 exit_rwsem(thread__namespaces_lock(thread));
124 exit_rwsem(thread__comm_lock(thread));
125 thread__free_stitch_list(thread);
126
127 if (thread__priv_destructor)
128 thread__priv_destructor(thread__priv(thread));
129
130 RC_CHK_FREE(thread);
131}
132
133struct thread *thread__get(struct thread *thread)
134{
135 struct thread *result;
136
137 if (RC_CHK_GET(result, thread))
138 refcount_inc(thread__refcnt(thread));
139
140 return result;
141}
142
143void thread__put(struct thread *thread)
144{
145 if (thread && refcount_dec_and_test(thread__refcnt(thread)))
146 thread__delete(thread);
147 else
148 RC_CHK_PUT(thread);
149}
150
151static struct namespaces *__thread__namespaces(struct thread *thread)
152{
153 if (list_empty(thread__namespaces_list(thread)))
154 return NULL;
155
156 return list_first_entry(thread__namespaces_list(thread), struct namespaces, list);
157}
158
159struct namespaces *thread__namespaces(struct thread *thread)
160{
161 struct namespaces *ns;
162
163 down_read(thread__namespaces_lock(thread));
164 ns = __thread__namespaces(thread);
165 up_read(thread__namespaces_lock(thread));
166
167 return ns;
168}
169
170static int __thread__set_namespaces(struct thread *thread, u64 timestamp,
171 struct perf_record_namespaces *event)
172{
173 struct namespaces *new, *curr = __thread__namespaces(thread);
174
175 new = namespaces__new(event);
176 if (!new)
177 return -ENOMEM;
178
179 list_add(&new->list, thread__namespaces_list(thread));
180
181 if (timestamp && curr) {
182 /*
183 * setns syscall must have changed few or all the namespaces
184 * of this thread. Update end time for the namespaces
185 * previously used.
186 */
187 curr = list_next_entry(new, list);
188 curr->end_time = timestamp;
189 }
190
191 return 0;
192}
193
194int thread__set_namespaces(struct thread *thread, u64 timestamp,
195 struct perf_record_namespaces *event)
196{
197 int ret;
198
199 down_write(thread__namespaces_lock(thread));
200 ret = __thread__set_namespaces(thread, timestamp, event);
201 up_write(thread__namespaces_lock(thread));
202 return ret;
203}
204
205static struct comm *__thread__comm(struct thread *thread)
206 SHARED_LOCKS_REQUIRED(thread__comm_lock(thread))
207{
208 if (list_empty(thread__comm_list(thread)))
209 return NULL;
210
211 return list_first_entry(thread__comm_list(thread), struct comm, list);
212}
213
214struct comm *thread__comm(struct thread *thread)
215{
216 struct comm *res = NULL;
217
218 down_read(thread__comm_lock(thread));
219 res = __thread__comm(thread);
220 up_read(thread__comm_lock(thread));
221 return res;
222}
223
224struct comm *thread__exec_comm(struct thread *thread)
225{
226 struct comm *comm, *last = NULL, *second_last = NULL;
227
228 down_read(thread__comm_lock(thread));
229 list_for_each_entry(comm, thread__comm_list(thread), list) {
230 if (comm->exec) {
231 up_read(thread__comm_lock(thread));
232 return comm;
233 }
234 second_last = last;
235 last = comm;
236 }
237 up_read(thread__comm_lock(thread));
238
239 /*
240 * 'last' with no start time might be the parent's comm of a synthesized
241 * thread (created by processing a synthesized fork event). For a main
242 * thread, that is very probably wrong. Prefer a later comm to avoid
243 * that case.
244 */
245 if (second_last && !last->start && thread__pid(thread) == thread__tid(thread))
246 return second_last;
247
248 return last;
249}
250
251static int ____thread__set_comm(struct thread *thread, const char *str,
252 u64 timestamp, bool exec)
253 EXCLUSIVE_LOCKS_REQUIRED(thread__comm_lock(thread))
254{
255 struct comm *new, *curr = __thread__comm(thread);
256
257 /* Override the default :tid entry */
258 if (!thread__comm_set(thread)) {
259 int err = comm__override(curr, str, timestamp, exec);
260 if (err)
261 return err;
262 } else {
263 new = comm__new(str, timestamp, exec);
264 if (!new)
265 return -ENOMEM;
266 list_add(&new->list, thread__comm_list(thread));
267
268 if (exec)
269 unwind__flush_access(thread__maps(thread));
270 }
271
272 thread__set_comm_set(thread, true);
273
274 return 0;
275}
276
277int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,
278 bool exec)
279{
280 int ret;
281
282 down_write(thread__comm_lock(thread));
283 ret = ____thread__set_comm(thread, str, timestamp, exec);
284 up_write(thread__comm_lock(thread));
285 return ret;
286}
287
288int thread__set_comm_from_proc(struct thread *thread)
289{
290 char path[64];
291 char *comm = NULL;
292 size_t sz;
293 int err = -1;
294
295 if (!(snprintf(path, sizeof(path), "%d/task/%d/comm",
296 thread__pid(thread), thread__tid(thread)) >= (int)sizeof(path)) &&
297 procfs__read_str(path, &comm, &sz) == 0) {
298 /* sz==0: read got nothing, e.g. race during exit teardown */
299 if (sz == 0) {
300 free(comm);
301 return -1;
302 }
303 comm[sz - 1] = '\0';
304 err = thread__set_comm(thread, comm, 0);
305 }
306
307 return err;
308}
309
310static const char *__thread__comm_str(struct thread *thread)
311 SHARED_LOCKS_REQUIRED(thread__comm_lock(thread))
312{
313 const struct comm *comm = __thread__comm(thread);
314
315 if (!comm)
316 return NULL;
317
318 return comm__str(comm);
319}
320
321const char *thread__comm_str(struct thread *thread)
322{
323 const char *str;
324
325 down_read(thread__comm_lock(thread));
326 str = __thread__comm_str(thread);
327 up_read(thread__comm_lock(thread));
328
329 return str;
330}
331
332static int __thread__comm_len(struct thread *thread, const char *comm)
333{
334 if (!comm)
335 return 0;
336 thread__set_comm_len(thread, strlen(comm));
337
338 return thread__var_comm_len(thread);
339}
340
341/* CHECKME: it should probably better return the max comm len from its comm list */
342int thread__comm_len(struct thread *thread)
343{
344 int comm_len = thread__var_comm_len(thread);
345
346 if (!comm_len) {
347 const char *comm;
348
349 down_read(thread__comm_lock(thread));
350 comm = __thread__comm_str(thread);
351 comm_len = __thread__comm_len(thread, comm);
352 up_read(thread__comm_lock(thread));
353 }
354
355 return comm_len;
356}
357
358size_t thread__fprintf(struct thread *thread, FILE *fp)
359{
360 return fprintf(fp, "Thread %d %s\n", thread__tid(thread), thread__comm_str(thread)) +
361 maps__fprintf(thread__maps(thread), fp);
362}
363
364int thread__insert_map(struct thread *thread, struct map *map)
365{
366 int ret;
367 uint16_t e_machine;
368
369 ret = maps__fixup_overlap_and_insert(thread__maps(thread), map);
370 if (ret)
371 return ret;
372
373 e_machine = thread__e_machine(thread, /*machine=*/NULL, /*e_flags=*/NULL);
374 return unwind__prepare_access(thread__maps(thread), e_machine);
375}
376
377static int thread__prepare_access(struct thread *thread)
378{
379 uint16_t e_machine = thread__e_machine(thread, /*machine=*/NULL, /*e_flags=*/NULL);
380
381 return unwind__prepare_access(thread__maps(thread), e_machine);
382}
383
384static int thread__clone_maps(struct thread *thread, struct thread *parent, bool do_maps_clone)
385{
386 /* This is new thread, we share map groups for process. */
387 if (thread__pid(thread) == thread__pid(parent))
388 return thread__prepare_access(thread);
389
390 if (maps__equal(thread__maps(thread), thread__maps(parent))) {
391 pr_debug("broken map groups on thread %d/%d parent %d/%d\n",
392 thread__pid(thread), thread__tid(thread),
393 thread__pid(parent), thread__tid(parent));
394 return 0;
395 }
396 /* But this one is new process, copy maps. */
397 return do_maps_clone ? maps__copy_from(thread__maps(thread), thread__maps(parent)) : 0;
398}
399
400int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp, bool do_maps_clone)
401{
402 if (thread__comm_set(parent)) {
403 const char *comm = thread__comm_str(parent);
404 int err;
405 if (!comm)
406 return -ENOMEM;
407 err = thread__set_comm(thread, comm, timestamp);
408 if (err)
409 return err;
410 }
411
412 thread__set_ppid(thread, thread__tid(parent));
413 return thread__clone_maps(thread, parent, do_maps_clone);
414}
415
416void thread__find_cpumode_addr_location(struct thread *thread, u64 addr,
417 bool symbols, struct addr_location *al)
418{
419 size_t i;
420 const u8 cpumodes[] = {
421 PERF_RECORD_MISC_USER,
422 PERF_RECORD_MISC_KERNEL,
423 PERF_RECORD_MISC_GUEST_USER,
424 PERF_RECORD_MISC_GUEST_KERNEL
425 };
426
427 for (i = 0; i < ARRAY_SIZE(cpumodes); i++) {
428 if (symbols)
429 thread__find_symbol(thread, cpumodes[i], addr, al);
430 else
431 thread__find_map(thread, cpumodes[i], addr, al);
432
433 if (al->map)
434 break;
435 }
436}
437
438static uint16_t read_proc_e_machine_for_pid(pid_t pid, uint32_t *e_flags, bool *is_big_endian)
439{
440 char path[6 /* "/proc/" */ + 11 /* max length of pid */ + 5 /* "/exe\0" */];
441 int fd;
442 uint16_t e_machine = EM_NONE;
443
444 snprintf(path, sizeof(path), "/proc/%d/exe", pid);
445 fd = open(path, O_RDONLY);
446 if (fd >= 0) {
447 e_machine = dso__read_e_machine_endian(/*optional_dso=*/NULL, fd, e_flags,
448 is_big_endian);
449 close(fd);
450 }
451 return e_machine;
452}
453
454struct thread__e_machine_callback_args {
455 struct machine *machine;
456 uint32_t e_flags;
457 uint16_t e_machine;
458 bool is_big_endian;
459};
460
461static int thread__e_machine_callback(struct map *map, void *_args)
462{
463 struct thread__e_machine_callback_args *args = _args;
464 struct dso *dso = map__dso(map);
465
466 if (!dso)
467 return 0; // No dso, continue search.
468
469 args->e_machine =
470 dso__e_machine_endian(dso, args->machine, &args->e_flags, &args->is_big_endian);
471 return args->e_machine != EM_NONE ? 1 /* stop search */ : 0 /* continue search */;
472}
473
474uint16_t thread__e_machine_endian(struct thread *thread, struct machine *machine, uint32_t *e_flags,
475 bool *is_big_endian)
476{
477 pid_t tid, pid;
478 uint16_t e_machine;
479 uint32_t local_e_flags = 0;
480 struct thread__e_machine_callback_args args;
481
482 if (!thread) {
483 if (is_big_endian) {
484 *is_big_endian = perf_arch_is_big_endian(
485 machine && machine->env ? perf_env__arch(machine->env) : NULL);
486 }
487 return perf_env__e_machine(machine ? machine->env : NULL, e_flags);
488 }
489
490 e_machine = RC_CHK_ACCESS(thread)->e_machine;
491 args.machine = machine;
492 args.e_flags = 0;
493 args.e_machine = EM_NONE;
494 args.is_big_endian = false;
495
496 if (e_machine != EM_NONE) {
497 if (e_flags)
498 *e_flags = thread__e_flags(thread);
499 if (is_big_endian)
500 *is_big_endian = thread__e_is_big_endian(thread);
501 return e_machine;
502 }
503
504 if (machine == NULL) {
505 struct maps *maps = thread__maps(thread);
506
507 machine = maps__machine(maps);
508 args.machine = machine;
509 }
510 tid = thread__tid(thread);
511 pid = thread__pid(thread);
512 if (pid != tid) {
513 struct thread *parent = machine__findnew_thread(machine, pid, pid);
514
515 if (parent) {
516 e_machine = thread__e_machine_endian(parent, machine, &local_e_flags,
517 &args.is_big_endian);
518 thread__put(parent);
519 goto out;
520 }
521 /* Something went wrong, fallback. */
522 }
523 /* Reading on the PID thread. First try to find from the maps. */
524 maps__for_each_map(thread__maps(thread), thread__e_machine_callback, &args);
525
526 if (args.e_machine != EM_NONE) {
527 e_machine = args.e_machine;
528 local_e_flags = args.e_flags;
529 } else {
530 /* Maps failed, perhaps we're live with map events disabled. */
531 bool is_live = machine->machines == NULL;
532
533 if (!is_live) {
534 /* Check if the session has a data file. */
535 struct perf_session *session = container_of(machine->machines,
536 struct perf_session,
537 machines);
538
539 is_live = !!session->data;
540 }
541 /* Read from /proc/pid/exe if live. */
542 if (is_live) {
543 e_machine = read_proc_e_machine_for_pid(pid, &local_e_flags,
544 &args.is_big_endian);
545 } else if (machine && machine->env) {
546 /* Offline analysis: fallback to environment metadata. */
547 e_machine = perf_env__e_machine(machine->env, &local_e_flags);
548 args.is_big_endian = perf_arch_is_big_endian(perf_env__arch(machine->env));
549 }
550 }
551out:
552 if (e_machine != EM_NONE) {
553 thread__set_e_flags(thread, local_e_flags);
554 thread__set_e_is_big_endian(thread, args.is_big_endian);
555 thread__set_e_machine(thread, e_machine);
556 if (is_big_endian)
557 *is_big_endian = args.is_big_endian;
558 } else {
559 e_machine = EM_HOST;
560 local_e_flags = EF_HOST;
561 if (is_big_endian)
562 *is_big_endian = (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__);
563 }
564 if (e_flags)
565 *e_flags = local_e_flags;
566 return e_machine;
567}
568
569struct thread *thread__main_thread(struct machine *machine, struct thread *thread)
570{
571 if (thread__pid(thread) == thread__tid(thread))
572 return thread__get(thread);
573
574 if (thread__pid(thread) == -1)
575 return NULL;
576
577 return machine__find_thread(machine, thread__pid(thread), thread__pid(thread));
578}
579
580int thread__memcpy(struct thread *thread, struct machine *machine,
581 void *buf, u64 ip, int len, bool *is64bit)
582{
583 u8 cpumode = PERF_RECORD_MISC_USER;
584 struct addr_location al;
585 struct dso *dso;
586 long offset;
587
588 if (machine__kernel_ip(machine, ip))
589 cpumode = PERF_RECORD_MISC_KERNEL;
590
591 addr_location__init(&al);
592 if (!thread__find_map(thread, cpumode, ip, &al)) {
593 addr_location__exit(&al);
594 return -1;
595 }
596
597 dso = map__dso(al.map);
598
599 if (!dso || dso__data(dso)->status == DSO_DATA_STATUS_ERROR || map__load(al.map) < 0) {
600 addr_location__exit(&al);
601 return -1;
602 }
603
604 offset = map__map_ip(al.map, ip);
605 if (is64bit)
606 *is64bit = dso__is_64_bit(dso);
607
608 addr_location__exit(&al);
609
610 return dso__data_read_offset(dso, machine, offset, buf, len);
611}
612
613void thread__free_stitch_list(struct thread *thread)
614{
615 struct lbr_stitch *lbr_stitch = thread__lbr_stitch(thread);
616 struct stitch_list *pos, *tmp;
617
618 if (!lbr_stitch)
619 return;
620
621 list_for_each_entry_safe(pos, tmp, &lbr_stitch->lists, node) {
622 map_symbol__exit(&pos->cursor.ms);
623 list_del_init(&pos->node);
624 free(pos);
625 }
626
627 list_for_each_entry_safe(pos, tmp, &lbr_stitch->free_lists, node) {
628 list_del_init(&pos->node);
629 free(pos);
630 }
631
632 for (unsigned int i = 0 ; i < lbr_stitch->prev_lbr_cursor_size; i++)
633 map_symbol__exit(&lbr_stitch->prev_lbr_cursor[i].ms);
634
635 zfree(&lbr_stitch->prev_lbr_cursor);
636 free(thread__lbr_stitch(thread));
637 thread__set_lbr_stitch(thread, NULL);
638}