xref: /openbmc/linux/tools/perf/util/thread.c (revision 5b394b2d) 
1 // SPDX-License-Identifier: GPL-2.0
2 #include "../perf.h"
3 #include <errno.h>
4 #include <stdlib.h>
5 #include <stdio.h>
6 #include <string.h>
7 #include <linux/kernel.h>
8 #include "session.h"
9 #include "thread.h"
10 #include "thread-stack.h"
11 #include "util.h"
12 #include "debug.h"
13 #include "namespaces.h"
14 #include "comm.h"
15 #include "unwind.h"
16 
17 #include <api/fs/fs.h>
18 
19 int thread__init_map_groups(struct thread *thread, struct machine *machine)
20 {
21 	pid_t pid = thread->pid_;
22 
23 	if (pid == thread->tid || pid == -1) {
24 		thread->mg = map_groups__new(machine);
25 	} else {
26 		struct thread *leader = __machine__findnew_thread(machine, pid, pid);
27 		if (leader) {
28 			thread->mg = map_groups__get(leader->mg);
29 			thread__put(leader);
30 		}
31 	}
32 
33 	return thread->mg ? 0 : -1;
34 }
35 
36 struct thread *thread__new(pid_t pid, pid_t tid)
37 {
38 	char *comm_str;
39 	struct comm *comm;
40 	struct thread *thread = zalloc(sizeof(*thread));
41 
42 	if (thread != NULL) {
43 		thread->pid_ = pid;
44 		thread->tid = tid;
45 		thread->ppid = -1;
46 		thread->cpu = -1;
47 		INIT_LIST_HEAD(&thread->namespaces_list);
48 		INIT_LIST_HEAD(&thread->comm_list);
49 		init_rwsem(&thread->namespaces_lock);
50 		init_rwsem(&thread->comm_lock);
51 
52 		comm_str = malloc(32);
53 		if (!comm_str)
54 			goto err_thread;
55 
56 		snprintf(comm_str, 32, ":%d", tid);
57 		comm = comm__new(comm_str, 0, false);
58 		free(comm_str);
59 		if (!comm)
60 			goto err_thread;
61 
62 		list_add(&comm->list, &thread->comm_list);
63 		refcount_set(&thread->refcnt, 1);
64 		RB_CLEAR_NODE(&thread->rb_node);
65 		/* Thread holds first ref to nsdata. */
66 		thread->nsinfo = nsinfo__new(pid);
67 	}
68 
69 	return thread;
70 
71 err_thread:
72 	free(thread);
73 	return NULL;
74 }
75 
76 void thread__delete(struct thread *thread)
77 {
78 	struct namespaces *namespaces, *tmp_namespaces;
79 	struct comm *comm, *tmp_comm;
80 
81 	BUG_ON(!RB_EMPTY_NODE(&thread->rb_node));
82 
83 	thread_stack__free(thread);
84 
85 	if (thread->mg) {
86 		map_groups__put(thread->mg);
87 		thread->mg = NULL;
88 	}
89 	down_write(&thread->namespaces_lock);
90 	list_for_each_entry_safe(namespaces, tmp_namespaces,
91 				 &thread->namespaces_list, list) {
92 		list_del(&namespaces->list);
93 		namespaces__free(namespaces);
94 	}
95 	up_write(&thread->namespaces_lock);
96 
97 	down_write(&thread->comm_lock);
98 	list_for_each_entry_safe(comm, tmp_comm, &thread->comm_list, list) {
99 		list_del(&comm->list);
100 		comm__free(comm);
101 	}
102 	up_write(&thread->comm_lock);
103 
104 	unwind__finish_access(thread);
105 	nsinfo__zput(thread->nsinfo);
106 
107 	exit_rwsem(&thread->namespaces_lock);
108 	exit_rwsem(&thread->comm_lock);
109 	free(thread);
110 }
111 
112 struct thread *thread__get(struct thread *thread)
113 {
114 	if (thread)
115 		refcount_inc(&thread->refcnt);
116 	return thread;
117 }
118 
119 void thread__put(struct thread *thread)
120 {
121 	if (thread && refcount_dec_and_test(&thread->refcnt)) {
122 		/*
123 		 * Remove it from the dead_threads list, as last reference
124 		 * is gone.
125 		 */
126 		list_del_init(&thread->node);
127 		thread__delete(thread);
128 	}
129 }
130 
131 struct namespaces *thread__namespaces(const struct thread *thread)
132 {
133 	if (list_empty(&thread->namespaces_list))
134 		return NULL;
135 
136 	return list_first_entry(&thread->namespaces_list, struct namespaces, list);
137 }
138 
139 static int __thread__set_namespaces(struct thread *thread, u64 timestamp,
140 				    struct namespaces_event *event)
141 {
142 	struct namespaces *new, *curr = thread__namespaces(thread);
143 
144 	new = namespaces__new(event);
145 	if (!new)
146 		return -ENOMEM;
147 
148 	list_add(&new->list, &thread->namespaces_list);
149 
150 	if (timestamp && curr) {
151 		/*
152 		 * setns syscall must have changed few or all the namespaces
153 		 * of this thread. Update end time for the namespaces
154 		 * previously used.
155 		 */
156 		curr = list_next_entry(new, list);
157 		curr->end_time = timestamp;
158 	}
159 
160 	return 0;
161 }
162 
163 int thread__set_namespaces(struct thread *thread, u64 timestamp,
164 			   struct namespaces_event *event)
165 {
166 	int ret;
167 
168 	down_write(&thread->namespaces_lock);
169 	ret = __thread__set_namespaces(thread, timestamp, event);
170 	up_write(&thread->namespaces_lock);
171 	return ret;
172 }
173 
174 struct comm *thread__comm(const struct thread *thread)
175 {
176 	if (list_empty(&thread->comm_list))
177 		return NULL;
178 
179 	return list_first_entry(&thread->comm_list, struct comm, list);
180 }
181 
182 struct comm *thread__exec_comm(const struct thread *thread)
183 {
184 	struct comm *comm, *last = NULL;
185 
186 	list_for_each_entry(comm, &thread->comm_list, list) {
187 		if (comm->exec)
188 			return comm;
189 		last = comm;
190 	}
191 
192 	return last;
193 }
194 
195 static int ____thread__set_comm(struct thread *thread, const char *str,
196 				u64 timestamp, bool exec)
197 {
198 	struct comm *new, *curr = thread__comm(thread);
199 
200 	/* Override the default :tid entry */
201 	if (!thread->comm_set) {
202 		int err = comm__override(curr, str, timestamp, exec);
203 		if (err)
204 			return err;
205 	} else {
206 		new = comm__new(str, timestamp, exec);
207 		if (!new)
208 			return -ENOMEM;
209 		list_add(&new->list, &thread->comm_list);
210 
211 		if (exec)
212 			unwind__flush_access(thread);
213 	}
214 
215 	thread->comm_set = true;
216 
217 	return 0;
218 }
219 
220 int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,
221 		       bool exec)
222 {
223 	int ret;
224 
225 	down_write(&thread->comm_lock);
226 	ret = ____thread__set_comm(thread, str, timestamp, exec);
227 	up_write(&thread->comm_lock);
228 	return ret;
229 }
230 
231 int thread__set_comm_from_proc(struct thread *thread)
232 {
233 	char path[64];
234 	char *comm = NULL;
235 	size_t sz;
236 	int err = -1;
237 
238 	if (!(snprintf(path, sizeof(path), "%d/task/%d/comm",
239 		       thread->pid_, thread->tid) >= (int)sizeof(path)) &&
240 	    procfs__read_str(path, &comm, &sz) == 0) {
241 		comm[sz - 1] = '\0';
242 		err = thread__set_comm(thread, comm, 0);
243 	}
244 
245 	return err;
246 }
247 
248 static const char *__thread__comm_str(const struct thread *thread)
249 {
250 	const struct comm *comm = thread__comm(thread);
251 
252 	if (!comm)
253 		return NULL;
254 
255 	return comm__str(comm);
256 }
257 
258 const char *thread__comm_str(const struct thread *thread)
259 {
260 	const char *str;
261 
262 	down_read((struct rw_semaphore *)&thread->comm_lock);
263 	str = __thread__comm_str(thread);
264 	up_read((struct rw_semaphore *)&thread->comm_lock);
265 
266 	return str;
267 }
268 
269 /* CHECKME: it should probably better return the max comm len from its comm list */
270 int thread__comm_len(struct thread *thread)
271 {
272 	if (!thread->comm_len) {
273 		const char *comm = thread__comm_str(thread);
274 		if (!comm)
275 			return 0;
276 		thread->comm_len = strlen(comm);
277 	}
278 
279 	return thread->comm_len;
280 }
281 
282 size_t thread__fprintf(struct thread *thread, FILE *fp)
283 {
284 	return fprintf(fp, "Thread %d %s\n", thread->tid, thread__comm_str(thread)) +
285 	       map_groups__fprintf(thread->mg, fp);
286 }
287 
288 int thread__insert_map(struct thread *thread, struct map *map)
289 {
290 	int ret;
291 
292 	ret = unwind__prepare_access(thread, map, NULL);
293 	if (ret)
294 		return ret;
295 
296 	map_groups__fixup_overlappings(thread->mg, map, stderr);
297 	map_groups__insert(thread->mg, map);
298 
299 	return 0;
300 }
301 
302 static int __thread__prepare_access(struct thread *thread)
303 {
304 	bool initialized = false;
305 	int err = 0;
306 	struct maps *maps = &thread->mg->maps;
307 	struct map *map;
308 
309 	down_read(&maps->lock);
310 
311 	for (map = maps__first(maps); map; map = map__next(map)) {
312 		err = unwind__prepare_access(thread, map, &initialized);
313 		if (err || initialized)
314 			break;
315 	}
316 
317 	up_read(&maps->lock);
318 
319 	return err;
320 }
321 
322 static int thread__prepare_access(struct thread *thread)
323 {
324 	int err = 0;
325 
326 	if (symbol_conf.use_callchain)
327 		err = __thread__prepare_access(thread);
328 
329 	return err;
330 }
331 
332 static int thread__clone_map_groups(struct thread *thread,
333 				    struct thread *parent)
334 {
335 	/* This is new thread, we share map groups for process. */
336 	if (thread->pid_ == parent->pid_)
337 		return thread__prepare_access(thread);
338 
339 	if (thread->mg == parent->mg) {
340 		pr_debug("broken map groups on thread %d/%d parent %d/%d\n",
341 			 thread->pid_, thread->tid, parent->pid_, parent->tid);
342 		return 0;
343 	}
344 
345 	/* But this one is new process, copy maps. */
346 	if (map_groups__clone(thread, parent->mg) < 0)
347 		return -ENOMEM;
348 
349 	return 0;
350 }
351 
352 int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp)
353 {
354 	if (parent->comm_set) {
355 		const char *comm = thread__comm_str(parent);
356 		int err;
357 		if (!comm)
358 			return -ENOMEM;
359 		err = thread__set_comm(thread, comm, timestamp);
360 		if (err)
361 			return err;
362 	}
363 
364 	thread->ppid = parent->tid;
365 	return thread__clone_map_groups(thread, parent);
366 }
367 
368 void thread__find_cpumode_addr_location(struct thread *thread, u64 addr,
369 					struct addr_location *al)
370 {
371 	size_t i;
372 	const u8 cpumodes[] = {
373 		PERF_RECORD_MISC_USER,
374 		PERF_RECORD_MISC_KERNEL,
375 		PERF_RECORD_MISC_GUEST_USER,
376 		PERF_RECORD_MISC_GUEST_KERNEL
377 	};
378 
379 	for (i = 0; i < ARRAY_SIZE(cpumodes); i++) {
380 		thread__find_symbol(thread, cpumodes[i], addr, al);
381 		if (al->map)
382 			break;
383 	}
384 }
385 
386 struct thread *thread__main_thread(struct machine *machine, struct thread *thread)
387 {
388 	if (thread->pid_ == thread->tid)
389 		return thread__get(thread);
390 
391 	if (thread->pid_ == -1)
392 		return NULL;
393 
394 	return machine__find_thread(machine, thread->pid_, thread->pid_);
395 }
396