Commit | Line | Data |
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f99be407 | 1 | /* |
b27f8e75 | 2 | * Copyright (C) 2008-2011 Mathieu Desnoyers |
1f8b0dff | 3 | * Copyright (C) 2009 Pierre-Marc Fournier |
f99be407 | 4 | * |
34e4b7db PMF |
5 | * This library is free software; you can redistribute it and/or |
6 | * modify it under the terms of the GNU Lesser General Public | |
f37142a4 MD |
7 | * License as published by the Free Software Foundation; |
8 | * version 2.1 of the License. | |
f99be407 | 9 | * |
34e4b7db | 10 | * This library is distributed in the hope that it will be useful, |
f99be407 | 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
34e4b7db PMF |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | * Lesser General Public License for more details. | |
f99be407 | 14 | * |
34e4b7db PMF |
15 | * You should have received a copy of the GNU Lesser General Public |
16 | * License along with this library; if not, write to the Free Software | |
17 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
1f8b0dff PMF |
18 | * |
19 | * Ported to userspace by Pierre-Marc Fournier. | |
f99be407 | 20 | */ |
1f8b0dff | 21 | |
b0c4126f | 22 | #define _LGPL_SOURCE |
474d745f | 23 | #include <errno.h> |
b728d87e MD |
24 | #include <stdint.h> |
25 | #include <stddef.h> | |
33661f97 | 26 | #include <stdio.h> |
44c72f10 | 27 | |
b728d87e | 28 | #include <urcu/arch.h> |
10544ee8 | 29 | #include <lttng/urcu/urcu-ust.h> |
10c56168 | 30 | #include <urcu/hlist.h> |
edaa1431 | 31 | #include <urcu/uatomic.h> |
b728d87e | 32 | #include <urcu/compiler.h> |
c082d14b | 33 | #include <urcu/system.h> |
44c72f10 MD |
34 | |
35 | #include <lttng/tracepoint.h> | |
ff412fb5 | 36 | #include <lttng/ust-abi.h> /* for LTTNG_UST_SYM_NAME_LEN */ |
44c72f10 MD |
37 | |
38 | #include <usterr-signal-safe.h> | |
35897f8b | 39 | #include <helper.h> |
474d745f | 40 | |
23c8854a | 41 | #include "tracepoint-internal.h" |
7dd08bec | 42 | #include "lttng-tracer-core.h" |
596c4223 | 43 | #include "jhash.h" |
8f3f8c99 | 44 | #include "error.h" |
b0c4126f | 45 | |
5517d34d | 46 | /* Test compiler support for weak symbols with hidden visibility. */ |
b0e63efd MD |
47 | int __tracepoint_test_symbol1 __attribute__((weak, visibility("hidden"))); |
48 | void *__tracepoint_test_symbol2 __attribute__((weak, visibility("hidden"))); | |
49 | struct { | |
50 | char a[24]; | |
51 | } __tracepoint_test_symbol3 __attribute__((weak, visibility("hidden"))); | |
5517d34d | 52 | |
f99be407 PMF |
53 | /* Set to 1 to enable tracepoint debug output */ |
54 | static const int tracepoint_debug; | |
b27f8e75 | 55 | static int initialized; |
0fd0de10 FD |
56 | |
57 | /* | |
58 | * If tracepoint_destructors_state = 1, tracepoint destructors are | |
59 | * enabled. They are disabled otherwise. | |
60 | */ | |
61 | static int tracepoint_destructors_state = 1; | |
62 | ||
63 | /* | |
64 | * Expose the now deprecated symbol __tracepoints__disable_destructors for | |
65 | * backward compatibility of applications built against old versions of | |
66 | * lttng-ust. We need to keep __tracepoints__disable_destructors up to date | |
67 | * within the new destructor disabling API because old applications read this | |
68 | * symbol directly. | |
69 | */ | |
70 | int __tracepoints__disable_destructors __attribute__((weak)); | |
71 | ||
1a206094 | 72 | static void (*new_tracepoint_cb)(struct lttng_ust_tracepoint *); |
f99be407 | 73 | |
8792fbae MD |
74 | /* |
75 | * tracepoint_mutex nests inside UST mutex. | |
76 | * | |
77 | * Note about interaction with fork/clone: UST does not hold the | |
78 | * tracepoint mutex across fork/clone because it is either: | |
79 | * - nested within UST mutex, in which case holding the UST mutex across | |
80 | * fork/clone suffice, | |
81 | * - taken by a library constructor, which should never race with a | |
82 | * fork/clone if the application is expected to continue running with | |
83 | * the same memory layout (no following exec()). | |
84 | */ | |
85 | static pthread_mutex_t tracepoint_mutex = PTHREAD_MUTEX_INITIALIZER; | |
86 | ||
efa2c591 MD |
87 | /* |
88 | * libraries that contain tracepoints (struct tracepoint_lib). | |
8792fbae | 89 | * Protected by tracepoint mutex. |
efa2c591 | 90 | */ |
0222e121 | 91 | static CDS_LIST_HEAD(libs); |
474d745f | 92 | |
f99be407 | 93 | /* |
8792fbae | 94 | * The tracepoint mutex protects the library tracepoints, the hash table, and |
17dfb34b | 95 | * the library list. |
8792fbae | 96 | * All calls to the tracepoint API must be protected by the tracepoint mutex, |
17dfb34b | 97 | * excepts calls to tracepoint_register_lib and |
8792fbae | 98 | * tracepoint_unregister_lib, which take the tracepoint mutex themselves. |
f99be407 | 99 | */ |
f99be407 PMF |
100 | |
101 | /* | |
102 | * Tracepoint hash table, containing the active tracepoints. | |
8792fbae | 103 | * Protected by tracepoint mutex. |
f99be407 | 104 | */ |
814f7df1 | 105 | #define TRACEPOINT_HASH_BITS 12 |
f99be407 | 106 | #define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS) |
10c56168 | 107 | static struct cds_hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE]; |
f99be407 | 108 | |
b27f8e75 MD |
109 | static CDS_LIST_HEAD(old_probes); |
110 | static int need_update; | |
111 | ||
baa1e0bc MD |
112 | static CDS_LIST_HEAD(release_queue); |
113 | static int release_queue_need_update; | |
114 | ||
f99be407 PMF |
115 | /* |
116 | * Note about RCU : | |
117 | * It is used to to delay the free of multiple probes array until a quiescent | |
118 | * state is reached. | |
8792fbae | 119 | * Tracepoint entries modifications are protected by the tracepoint mutex. |
f99be407 PMF |
120 | */ |
121 | struct tracepoint_entry { | |
10c56168 | 122 | struct cds_hlist_node hlist; |
1a206094 | 123 | struct lttng_ust_tracepoint_probe *probes; |
f99be407 | 124 | int refcount; /* Number of times armed. 0 if disarmed. */ |
8a7ad54b | 125 | int callsite_refcount; /* how many libs use this tracepoint */ |
2c05c691 FD |
126 | char *signature; |
127 | char *name; | |
f99be407 PMF |
128 | }; |
129 | ||
130 | struct tp_probes { | |
131 | union { | |
0222e121 | 132 | struct cds_list_head list; |
ade7037b MD |
133 | /* Field below only used for call_rcu scheme */ |
134 | /* struct rcu_head head; */ | |
f99be407 | 135 | } u; |
1a206094 | 136 | struct lttng_ust_tracepoint_probe probes[0]; |
f99be407 PMF |
137 | }; |
138 | ||
3469bbbe MD |
139 | /* |
140 | * Callsite hash table, containing the tracepoint call sites. | |
141 | * Protected by tracepoint mutex. | |
142 | */ | |
143 | #define CALLSITE_HASH_BITS 12 | |
144 | #define CALLSITE_TABLE_SIZE (1 << CALLSITE_HASH_BITS) | |
145 | static struct cds_hlist_head callsite_table[CALLSITE_TABLE_SIZE]; | |
146 | ||
147 | struct callsite_entry { | |
148 | struct cds_hlist_node hlist; /* hash table node */ | |
149 | struct cds_list_head node; /* lib list of callsites node */ | |
1a206094 | 150 | struct lttng_ust_tracepoint *tp; |
2c05c691 | 151 | bool tp_entry_callsite_ref; /* Has a tp_entry took a ref on this callsite */ |
3469bbbe MD |
152 | }; |
153 | ||
10544ee8 MD |
154 | static int tracepoint_v1_api_used; |
155 | static void (*lttng_ust_liburcu_bp_synchronize_rcu)(void); | |
156 | static void (*lttng_ust_liburcu_bp_rcu_read_lock)(void); | |
157 | static void (*lttng_ust_liburcu_bp_rcu_read_unlock)(void); | |
158 | void (*lttng_ust_liburcu_bp_before_fork)(void); | |
159 | void (*lttng_ust_liburcu_bp_after_fork_parent)(void); | |
160 | void (*lttng_ust_liburcu_bp_after_fork_child)(void); | |
161 | ||
162 | static bool lttng_ust_tracepoint_v1_used(void) | |
163 | { | |
164 | return uatomic_read(&tracepoint_v1_api_used); | |
165 | } | |
166 | ||
167 | static void lttng_ust_tracepoint_set_v1_used(void) | |
168 | { | |
169 | if (!lttng_ust_tracepoint_v1_used()) { | |
170 | /* | |
171 | * Perform dlsym here rather than lazily on first use to | |
172 | * eliminate nesting of dynamic loader lock (used within | |
173 | * dlsym) inside the ust lock. | |
174 | */ | |
175 | if (!lttng_ust_liburcu_bp_synchronize_rcu) { | |
176 | lttng_ust_liburcu_bp_synchronize_rcu = URCU_FORCE_CAST(void (*)(void), | |
177 | dlsym(RTLD_DEFAULT, "synchronize_rcu_bp")); | |
a58c831a MD |
178 | /* |
179 | * Allow legacy applications compiled without | |
180 | * _LGPL_SOURCE to use v1 API. Those are not | |
181 | * required to be linked against liburcu-bp, | |
182 | * so in those situations the liburcu-bp symbols | |
183 | * are not present in the global symbol table, | |
184 | * and we do not need to call urcu-bp | |
185 | * synchronize. | |
186 | * | |
187 | * However, nothing prevents a _LGPL_SOURCE | |
188 | * instrumented library loaded afterwards to | |
189 | * require liburcu-bp, so we need to check again | |
190 | * in that situation. | |
191 | */ | |
10544ee8 | 192 | if (!lttng_ust_liburcu_bp_synchronize_rcu) |
a58c831a | 193 | return; |
10544ee8 MD |
194 | } |
195 | if (!lttng_ust_liburcu_bp_before_fork) { | |
196 | lttng_ust_liburcu_bp_before_fork = URCU_FORCE_CAST(void (*)(void), | |
197 | dlsym(RTLD_DEFAULT, "rcu_bp_before_fork")); | |
198 | if (!lttng_ust_liburcu_bp_before_fork) | |
199 | abort(); | |
200 | } | |
201 | if (!lttng_ust_liburcu_bp_after_fork_parent) { | |
202 | lttng_ust_liburcu_bp_after_fork_parent = URCU_FORCE_CAST(void (*)(void), | |
203 | dlsym(RTLD_DEFAULT, "rcu_bp_after_fork_parent")); | |
204 | if (!lttng_ust_liburcu_bp_after_fork_parent) | |
205 | abort(); | |
206 | } | |
207 | if (!lttng_ust_liburcu_bp_after_fork_child) { | |
208 | lttng_ust_liburcu_bp_after_fork_child = URCU_FORCE_CAST(void (*)(void), | |
209 | dlsym(RTLD_DEFAULT, "rcu_bp_after_fork_child")); | |
210 | if (!lttng_ust_liburcu_bp_after_fork_child) | |
211 | abort(); | |
212 | } | |
213 | if (!lttng_ust_liburcu_bp_rcu_read_lock) { | |
214 | lttng_ust_liburcu_bp_rcu_read_lock = URCU_FORCE_CAST(void (*)(void), | |
215 | dlsym(RTLD_DEFAULT, "rcu_read_lock_bp")); | |
216 | if (!lttng_ust_liburcu_bp_rcu_read_lock) | |
217 | abort(); | |
218 | } | |
219 | if (!lttng_ust_liburcu_bp_rcu_read_unlock) { | |
220 | lttng_ust_liburcu_bp_rcu_read_unlock = URCU_FORCE_CAST(void (*)(void), | |
221 | dlsym(RTLD_DEFAULT, "rcu_read_unlock_bp")); | |
222 | if (!lttng_ust_liburcu_bp_rcu_read_unlock) | |
223 | abort(); | |
224 | } | |
225 | ||
226 | /* Fixup URCU bp TLS. */ | |
227 | lttng_ust_liburcu_bp_rcu_read_lock(); | |
228 | lttng_ust_liburcu_bp_rcu_read_unlock(); | |
229 | ||
230 | uatomic_set(&tracepoint_v1_api_used, 1); | |
231 | } | |
232 | } | |
233 | ||
5e6df7ea | 234 | /* coverity[+alloc] */ |
efa2c591 | 235 | static void *allocate_probes(int count) |
f99be407 | 236 | { |
1a206094 SM |
237 | struct tp_probes *p = |
238 | zmalloc(count * sizeof(struct lttng_ust_tracepoint_probe) | |
239 | + sizeof(struct tp_probes)); | |
f99be407 PMF |
240 | return p == NULL ? NULL : p->probes; |
241 | } | |
242 | ||
5e6df7ea | 243 | /* coverity[+free : arg-0] */ |
efa2c591 | 244 | static void release_probes(void *old) |
f99be407 PMF |
245 | { |
246 | if (old) { | |
b728d87e | 247 | struct tp_probes *tp_probes = caa_container_of(old, |
f99be407 | 248 | struct tp_probes, probes[0]); |
10544ee8 | 249 | lttng_ust_synchronize_trace(); |
909bc43f | 250 | free(tp_probes); |
f99be407 PMF |
251 | } |
252 | } | |
253 | ||
254 | static void debug_print_probes(struct tracepoint_entry *entry) | |
255 | { | |
256 | int i; | |
257 | ||
9dec086e | 258 | if (!tracepoint_debug || !entry->probes) |
f99be407 PMF |
259 | return; |
260 | ||
9dec086e NC |
261 | for (i = 0; entry->probes[i].func; i++) |
262 | DBG("Probe %d : %p", i, entry->probes[i].func); | |
f99be407 PMF |
263 | } |
264 | ||
265 | static void * | |
9dec086e | 266 | tracepoint_entry_add_probe(struct tracepoint_entry *entry, |
fbdeb5ec | 267 | void (*probe)(void), void *data) |
f99be407 PMF |
268 | { |
269 | int nr_probes = 0; | |
1a206094 | 270 | struct lttng_ust_tracepoint_probe *old, *new; |
f99be407 | 271 | |
d7509147 MD |
272 | if (!probe) { |
273 | WARN_ON(1); | |
274 | return ERR_PTR(-EINVAL); | |
275 | } | |
f99be407 | 276 | debug_print_probes(entry); |
9dec086e | 277 | old = entry->probes; |
f99be407 PMF |
278 | if (old) { |
279 | /* (N -> N+1), (N != 0, 1) probes */ | |
9dec086e NC |
280 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) |
281 | if (old[nr_probes].func == probe && | |
282 | old[nr_probes].data == data) | |
f99be407 PMF |
283 | return ERR_PTR(-EEXIST); |
284 | } | |
285 | /* + 2 : one for new probe, one for NULL func */ | |
286 | new = allocate_probes(nr_probes + 2); | |
287 | if (new == NULL) | |
288 | return ERR_PTR(-ENOMEM); | |
289 | if (old) | |
1a206094 SM |
290 | memcpy(new, old, |
291 | nr_probes * sizeof(struct lttng_ust_tracepoint_probe)); | |
9dec086e NC |
292 | new[nr_probes].func = probe; |
293 | new[nr_probes].data = data; | |
294 | new[nr_probes + 1].func = NULL; | |
f99be407 | 295 | entry->refcount = nr_probes + 1; |
9dec086e | 296 | entry->probes = new; |
f99be407 PMF |
297 | debug_print_probes(entry); |
298 | return old; | |
299 | } | |
300 | ||
301 | static void * | |
fbdeb5ec MD |
302 | tracepoint_entry_remove_probe(struct tracepoint_entry *entry, |
303 | void (*probe)(void), void *data) | |
f99be407 PMF |
304 | { |
305 | int nr_probes = 0, nr_del = 0, i; | |
1a206094 | 306 | struct lttng_ust_tracepoint_probe *old, *new; |
f99be407 | 307 | |
9dec086e | 308 | old = entry->probes; |
f99be407 PMF |
309 | |
310 | if (!old) | |
311 | return ERR_PTR(-ENOENT); | |
312 | ||
313 | debug_print_probes(entry); | |
314 | /* (N -> M), (N > 1, M >= 0) probes */ | |
956c6fab MD |
315 | if (probe) { |
316 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) { | |
317 | if (old[nr_probes].func == probe && | |
318 | old[nr_probes].data == data) | |
319 | nr_del++; | |
320 | } | |
f99be407 PMF |
321 | } |
322 | ||
323 | if (nr_probes - nr_del == 0) { | |
324 | /* N -> 0, (N > 1) */ | |
9dec086e | 325 | entry->probes = NULL; |
f99be407 PMF |
326 | entry->refcount = 0; |
327 | debug_print_probes(entry); | |
328 | return old; | |
329 | } else { | |
330 | int j = 0; | |
331 | /* N -> M, (N > 1, M > 0) */ | |
332 | /* + 1 for NULL */ | |
333 | new = allocate_probes(nr_probes - nr_del + 1); | |
334 | if (new == NULL) | |
335 | return ERR_PTR(-ENOMEM); | |
9dec086e | 336 | for (i = 0; old[i].func; i++) |
956c6fab | 337 | if (old[i].func != probe || old[i].data != data) |
f99be407 | 338 | new[j++] = old[i]; |
9dec086e | 339 | new[nr_probes - nr_del].func = NULL; |
f99be407 | 340 | entry->refcount = nr_probes - nr_del; |
9dec086e | 341 | entry->probes = new; |
f99be407 PMF |
342 | } |
343 | debug_print_probes(entry); | |
344 | return old; | |
345 | } | |
346 | ||
347 | /* | |
348 | * Get tracepoint if the tracepoint is present in the tracepoint hash table. | |
8792fbae | 349 | * Must be called with tracepoint mutex held. |
f99be407 PMF |
350 | * Returns NULL if not present. |
351 | */ | |
352 | static struct tracepoint_entry *get_tracepoint(const char *name) | |
353 | { | |
10c56168 DG |
354 | struct cds_hlist_head *head; |
355 | struct cds_hlist_node *node; | |
f99be407 | 356 | struct tracepoint_entry *e; |
ff412fb5 MD |
357 | size_t name_len = strlen(name); |
358 | uint32_t hash; | |
f99be407 | 359 | |
ff412fb5 MD |
360 | if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { |
361 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); | |
362 | name_len = LTTNG_UST_SYM_NAME_LEN - 1; | |
363 | } | |
364 | hash = jhash(name, name_len, 0); | |
f99be407 | 365 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
10c56168 | 366 | cds_hlist_for_each_entry(e, node, head, hlist) { |
ff412fb5 | 367 | if (!strncmp(name, e->name, LTTNG_UST_SYM_NAME_LEN - 1)) |
f99be407 PMF |
368 | return e; |
369 | } | |
370 | return NULL; | |
371 | } | |
372 | ||
373 | /* | |
374 | * Add the tracepoint to the tracepoint hash table. Must be called with | |
8792fbae | 375 | * tracepoint mutex held. |
f99be407 | 376 | */ |
67e5f391 MD |
377 | static struct tracepoint_entry *add_tracepoint(const char *name, |
378 | const char *signature) | |
f99be407 | 379 | { |
10c56168 DG |
380 | struct cds_hlist_head *head; |
381 | struct cds_hlist_node *node; | |
f99be407 | 382 | struct tracepoint_entry *e; |
ff412fb5 | 383 | size_t name_len = strlen(name); |
2c05c691 FD |
384 | size_t sig_len = strlen(signature); |
385 | size_t sig_off, name_off; | |
ff412fb5 | 386 | uint32_t hash; |
f99be407 | 387 | |
ff412fb5 MD |
388 | if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { |
389 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); | |
390 | name_len = LTTNG_UST_SYM_NAME_LEN - 1; | |
391 | } | |
392 | hash = jhash(name, name_len, 0); | |
f99be407 | 393 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
10c56168 | 394 | cds_hlist_for_each_entry(e, node, head, hlist) { |
ff412fb5 | 395 | if (!strncmp(name, e->name, LTTNG_UST_SYM_NAME_LEN - 1)) { |
c1f20530 | 396 | DBG("tracepoint %s busy", name); |
f99be407 PMF |
397 | return ERR_PTR(-EEXIST); /* Already there */ |
398 | } | |
399 | } | |
2c05c691 | 400 | |
f99be407 | 401 | /* |
2c05c691 FD |
402 | * Using zmalloc here to allocate a variable length elements: name and |
403 | * signature. Could cause some memory fragmentation if overused. | |
f99be407 | 404 | */ |
2c05c691 FD |
405 | name_off = sizeof(struct tracepoint_entry); |
406 | sig_off = name_off + name_len + 1; | |
407 | ||
408 | e = zmalloc(sizeof(struct tracepoint_entry) + name_len + 1 + sig_len + 1); | |
f99be407 PMF |
409 | if (!e) |
410 | return ERR_PTR(-ENOMEM); | |
2c05c691 FD |
411 | e->name = (char *) e + name_off; |
412 | memcpy(e->name, name, name_len + 1); | |
ff412fb5 | 413 | e->name[name_len] = '\0'; |
2c05c691 FD |
414 | |
415 | e->signature = (char *) e + sig_off; | |
416 | memcpy(e->signature, signature, sig_len + 1); | |
417 | e->signature[sig_len] = '\0'; | |
418 | ||
9dec086e | 419 | e->probes = NULL; |
f99be407 | 420 | e->refcount = 0; |
8a7ad54b | 421 | e->callsite_refcount = 0; |
2c05c691 | 422 | |
10c56168 | 423 | cds_hlist_add_head(&e->hlist, head); |
f99be407 PMF |
424 | return e; |
425 | } | |
426 | ||
427 | /* | |
428 | * Remove the tracepoint from the tracepoint hash table. Must be called with | |
8792fbae | 429 | * tracepoint mutex held. |
f99be407 | 430 | */ |
efa2c591 | 431 | static void remove_tracepoint(struct tracepoint_entry *e) |
f99be407 | 432 | { |
10c56168 | 433 | cds_hlist_del(&e->hlist); |
909bc43f | 434 | free(e); |
f99be407 PMF |
435 | } |
436 | ||
437 | /* | |
438 | * Sets the probe callback corresponding to one tracepoint. | |
439 | */ | |
440 | static void set_tracepoint(struct tracepoint_entry **entry, | |
1a206094 | 441 | struct lttng_ust_tracepoint *elem, int active) |
f99be407 | 442 | { |
ff412fb5 | 443 | WARN_ON(strncmp((*entry)->name, elem->name, LTTNG_UST_SYM_NAME_LEN - 1) != 0); |
67e5f391 MD |
444 | /* |
445 | * Check that signatures match before connecting a probe to a | |
446 | * tracepoint. Warn the user if they don't. | |
447 | */ | |
448 | if (strcmp(elem->signature, (*entry)->signature) != 0) { | |
449 | static int warned = 0; | |
450 | ||
451 | /* Only print once, don't flood console. */ | |
452 | if (!warned) { | |
453 | WARN("Tracepoint signature mismatch, not enabling one or more tracepoints. Ensure that the tracepoint probes prototypes match the application."); | |
454 | WARN("Tracepoint \"%s\" signatures: call: \"%s\" vs probe: \"%s\".", | |
455 | elem->name, elem->signature, (*entry)->signature); | |
456 | warned = 1; | |
457 | } | |
458 | /* Don't accept connecting non-matching signatures. */ | |
459 | return; | |
460 | } | |
f99be407 PMF |
461 | |
462 | /* | |
0222e121 | 463 | * rcu_assign_pointer has a cmm_smp_wmb() which makes sure that the new |
f99be407 PMF |
464 | * probe callbacks array is consistent before setting a pointer to it. |
465 | * This array is referenced by __DO_TRACE from | |
0222e121 | 466 | * include/linux/tracepoints.h. A matching cmm_smp_read_barrier_depends() |
f99be407 PMF |
467 | * is used. |
468 | */ | |
10544ee8 | 469 | lttng_ust_rcu_assign_pointer(elem->probes, (*entry)->probes); |
c082d14b | 470 | CMM_STORE_SHARED(elem->state, active); |
f99be407 PMF |
471 | } |
472 | ||
473 | /* | |
474 | * Disable a tracepoint and its probe callback. | |
475 | * Note: only waiting an RCU period after setting elem->call to the empty | |
476 | * function insures that the original callback is not used anymore. This insured | |
477 | * by preempt_disable around the call site. | |
478 | */ | |
1a206094 | 479 | static void disable_tracepoint(struct lttng_ust_tracepoint *elem) |
f99be407 | 480 | { |
c082d14b | 481 | CMM_STORE_SHARED(elem->state, 0); |
10544ee8 | 482 | lttng_ust_rcu_assign_pointer(elem->probes, NULL); |
f99be407 PMF |
483 | } |
484 | ||
33f8ed87 MD |
485 | /* |
486 | * Add the callsite to the callsite hash table. Must be called with | |
487 | * tracepoint mutex held. | |
488 | */ | |
1a206094 | 489 | static void add_callsite(struct tracepoint_lib * lib, struct lttng_ust_tracepoint *tp) |
33f8ed87 MD |
490 | { |
491 | struct cds_hlist_head *head; | |
492 | struct callsite_entry *e; | |
493 | const char *name = tp->name; | |
494 | size_t name_len = strlen(name); | |
495 | uint32_t hash; | |
8a7ad54b | 496 | struct tracepoint_entry *tp_entry; |
33f8ed87 MD |
497 | |
498 | if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { | |
499 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); | |
500 | name_len = LTTNG_UST_SYM_NAME_LEN - 1; | |
501 | } | |
502 | hash = jhash(name, name_len, 0); | |
503 | head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)]; | |
504 | e = zmalloc(sizeof(struct callsite_entry)); | |
d6297168 MD |
505 | if (!e) { |
506 | PERROR("Unable to add callsite for tracepoint \"%s\"", name); | |
507 | return; | |
508 | } | |
33f8ed87 MD |
509 | cds_hlist_add_head(&e->hlist, head); |
510 | e->tp = tp; | |
511 | cds_list_add(&e->node, &lib->callsites); | |
8a7ad54b IJ |
512 | |
513 | tp_entry = get_tracepoint(name); | |
514 | if (!tp_entry) | |
515 | return; | |
516 | tp_entry->callsite_refcount++; | |
2c05c691 | 517 | e->tp_entry_callsite_ref = true; |
33f8ed87 MD |
518 | } |
519 | ||
520 | /* | |
521 | * Remove the callsite from the callsite hash table and from lib | |
522 | * callsite list. Must be called with tracepoint mutex held. | |
523 | */ | |
524 | static void remove_callsite(struct callsite_entry *e) | |
525 | { | |
8a7ad54b IJ |
526 | struct tracepoint_entry *tp_entry; |
527 | ||
528 | tp_entry = get_tracepoint(e->tp->name); | |
529 | if (tp_entry) { | |
2c05c691 FD |
530 | if (e->tp_entry_callsite_ref) |
531 | tp_entry->callsite_refcount--; | |
8a7ad54b IJ |
532 | if (tp_entry->callsite_refcount == 0) |
533 | disable_tracepoint(e->tp); | |
534 | } | |
33f8ed87 MD |
535 | cds_hlist_del(&e->hlist); |
536 | cds_list_del(&e->node); | |
537 | free(e); | |
538 | } | |
539 | ||
3469bbbe MD |
540 | /* |
541 | * Enable/disable all callsites based on the state of a specific | |
542 | * tracepoint entry. | |
543 | * Must be called with tracepoint mutex held. | |
544 | */ | |
545 | static void tracepoint_sync_callsites(const char *name) | |
546 | { | |
547 | struct cds_hlist_head *head; | |
548 | struct cds_hlist_node *node; | |
549 | struct callsite_entry *e; | |
550 | size_t name_len = strlen(name); | |
551 | uint32_t hash; | |
552 | struct tracepoint_entry *tp_entry; | |
553 | ||
554 | tp_entry = get_tracepoint(name); | |
555 | if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { | |
556 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); | |
557 | name_len = LTTNG_UST_SYM_NAME_LEN - 1; | |
558 | } | |
559 | hash = jhash(name, name_len, 0); | |
560 | head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)]; | |
561 | cds_hlist_for_each_entry(e, node, head, hlist) { | |
1a206094 | 562 | struct lttng_ust_tracepoint *tp = e->tp; |
3469bbbe MD |
563 | |
564 | if (strncmp(name, tp->name, LTTNG_UST_SYM_NAME_LEN - 1)) | |
565 | continue; | |
566 | if (tp_entry) { | |
2c05c691 FD |
567 | if (!e->tp_entry_callsite_ref) { |
568 | tp_entry->callsite_refcount++; | |
569 | e->tp_entry_callsite_ref = true; | |
570 | } | |
3469bbbe MD |
571 | set_tracepoint(&tp_entry, tp, |
572 | !!tp_entry->refcount); | |
573 | } else { | |
574 | disable_tracepoint(tp); | |
2c05c691 | 575 | e->tp_entry_callsite_ref = false; |
3469bbbe MD |
576 | } |
577 | } | |
578 | } | |
579 | ||
f99be407 PMF |
580 | /** |
581 | * tracepoint_update_probe_range - Update a probe range | |
582 | * @begin: beginning of the range | |
583 | * @end: end of the range | |
584 | * | |
585 | * Updates the probe callback corresponding to a range of tracepoints. | |
586 | */ | |
b27f8e75 | 587 | static |
1a206094 SM |
588 | void tracepoint_update_probe_range(struct lttng_ust_tracepoint * const *begin, |
589 | struct lttng_ust_tracepoint * const *end) | |
f99be407 | 590 | { |
1a206094 | 591 | struct lttng_ust_tracepoint * const *iter; |
f99be407 PMF |
592 | struct tracepoint_entry *mark_entry; |
593 | ||
f99be407 | 594 | for (iter = begin; iter < end; iter++) { |
f08ebbe2 MD |
595 | if (!*iter) |
596 | continue; /* skip dummy */ | |
f218ff28 MD |
597 | if (!(*iter)->name) { |
598 | disable_tracepoint(*iter); | |
9dec086e NC |
599 | continue; |
600 | } | |
f218ff28 | 601 | mark_entry = get_tracepoint((*iter)->name); |
f99be407 | 602 | if (mark_entry) { |
f218ff28 | 603 | set_tracepoint(&mark_entry, *iter, |
f99be407 PMF |
604 | !!mark_entry->refcount); |
605 | } else { | |
f218ff28 | 606 | disable_tracepoint(*iter); |
f99be407 PMF |
607 | } |
608 | } | |
f99be407 PMF |
609 | } |
610 | ||
5da10905 | 611 | static void lib_update_tracepoints(struct tracepoint_lib *lib) |
772030fe | 612 | { |
5da10905 MD |
613 | tracepoint_update_probe_range(lib->tracepoints_start, |
614 | lib->tracepoints_start + lib->tracepoints_count); | |
772030fe PMF |
615 | } |
616 | ||
3469bbbe MD |
617 | static void lib_register_callsites(struct tracepoint_lib *lib) |
618 | { | |
1a206094 SM |
619 | struct lttng_ust_tracepoint * const *begin; |
620 | struct lttng_ust_tracepoint * const *end; | |
621 | struct lttng_ust_tracepoint * const *iter; | |
3469bbbe MD |
622 | |
623 | begin = lib->tracepoints_start; | |
624 | end = lib->tracepoints_start + lib->tracepoints_count; | |
625 | ||
626 | for (iter = begin; iter < end; iter++) { | |
627 | if (!*iter) | |
628 | continue; /* skip dummy */ | |
629 | if (!(*iter)->name) { | |
630 | continue; | |
631 | } | |
60d87029 | 632 | add_callsite(lib, *iter); |
3469bbbe MD |
633 | } |
634 | } | |
635 | ||
636 | static void lib_unregister_callsites(struct tracepoint_lib *lib) | |
637 | { | |
638 | struct callsite_entry *callsite, *tmp; | |
639 | ||
640 | cds_list_for_each_entry_safe(callsite, tmp, &lib->callsites, node) | |
641 | remove_callsite(callsite); | |
642 | } | |
643 | ||
f99be407 PMF |
644 | /* |
645 | * Update probes, removing the faulty probes. | |
646 | */ | |
647 | static void tracepoint_update_probes(void) | |
648 | { | |
5da10905 MD |
649 | struct tracepoint_lib *lib; |
650 | ||
b27f8e75 | 651 | /* tracepoints registered from libraries and executable. */ |
5da10905 MD |
652 | cds_list_for_each_entry(lib, &libs, list) |
653 | lib_update_tracepoints(lib); | |
f99be407 PMF |
654 | } |
655 | ||
1a206094 | 656 | static struct lttng_ust_tracepoint_probe * |
fbdeb5ec | 657 | tracepoint_add_probe(const char *name, void (*probe)(void), void *data, |
67e5f391 | 658 | const char *signature) |
f99be407 PMF |
659 | { |
660 | struct tracepoint_entry *entry; | |
1a206094 | 661 | struct lttng_ust_tracepoint_probe *old; |
f99be407 PMF |
662 | |
663 | entry = get_tracepoint(name); | |
2c05c691 FD |
664 | if (entry) { |
665 | if (strcmp(entry->signature, signature) != 0) { | |
666 | ERR("Tracepoint and probe signature do not match."); | |
667 | return ERR_PTR(-EINVAL); | |
668 | } | |
669 | } else { | |
67e5f391 | 670 | entry = add_tracepoint(name, signature); |
f99be407 | 671 | if (IS_ERR(entry)) |
1a206094 | 672 | return (struct lttng_ust_tracepoint_probe *)entry; |
f99be407 | 673 | } |
9dec086e | 674 | old = tracepoint_entry_add_probe(entry, probe, data); |
f99be407 PMF |
675 | if (IS_ERR(old) && !entry->refcount) |
676 | remove_tracepoint(entry); | |
677 | return old; | |
678 | } | |
679 | ||
baa1e0bc MD |
680 | static void tracepoint_release_queue_add_old_probes(void *old) |
681 | { | |
682 | release_queue_need_update = 1; | |
683 | if (old) { | |
684 | struct tp_probes *tp_probes = caa_container_of(old, | |
685 | struct tp_probes, probes[0]); | |
686 | cds_list_add(&tp_probes->u.list, &release_queue); | |
687 | } | |
688 | } | |
689 | ||
f99be407 | 690 | /** |
81614639 | 691 | * __tracepoint_probe_register - Connect a probe to a tracepoint |
f99be407 PMF |
692 | * @name: tracepoint name |
693 | * @probe: probe handler | |
694 | * | |
695 | * Returns 0 if ok, error value on error. | |
696 | * The probe address must at least be aligned on the architecture pointer size. | |
8792fbae | 697 | * Called with the tracepoint mutex held. |
f99be407 | 698 | */ |
fbdeb5ec MD |
699 | int __tracepoint_probe_register(const char *name, void (*probe)(void), |
700 | void *data, const char *signature) | |
f99be407 PMF |
701 | { |
702 | void *old; | |
8792fbae | 703 | int ret = 0; |
f99be407 | 704 | |
05780d81 MD |
705 | DBG("Registering probe to tracepoint %s", name); |
706 | ||
8792fbae | 707 | pthread_mutex_lock(&tracepoint_mutex); |
67e5f391 | 708 | old = tracepoint_add_probe(name, probe, data, signature); |
8792fbae MD |
709 | if (IS_ERR(old)) { |
710 | ret = PTR_ERR(old); | |
711 | goto end; | |
712 | } | |
f99be407 | 713 | |
3469bbbe | 714 | tracepoint_sync_callsites(name); |
f99be407 | 715 | release_probes(old); |
8792fbae MD |
716 | end: |
717 | pthread_mutex_unlock(&tracepoint_mutex); | |
718 | return ret; | |
f99be407 | 719 | } |
f99be407 | 720 | |
baa1e0bc MD |
721 | /* |
722 | * Caller needs to invoke __tracepoint_probe_release_queue() after | |
723 | * calling __tracepoint_probe_register_queue_release() one or multiple | |
724 | * times to ensure it does not leak memory. | |
725 | */ | |
726 | int __tracepoint_probe_register_queue_release(const char *name, | |
727 | void (*probe)(void), void *data, const char *signature) | |
728 | { | |
729 | void *old; | |
730 | int ret = 0; | |
731 | ||
732 | DBG("Registering probe to tracepoint %s. Queuing release.", name); | |
733 | ||
734 | pthread_mutex_lock(&tracepoint_mutex); | |
735 | old = tracepoint_add_probe(name, probe, data, signature); | |
736 | if (IS_ERR(old)) { | |
737 | ret = PTR_ERR(old); | |
738 | goto end; | |
739 | } | |
740 | ||
741 | tracepoint_sync_callsites(name); | |
742 | tracepoint_release_queue_add_old_probes(old); | |
743 | end: | |
744 | pthread_mutex_unlock(&tracepoint_mutex); | |
745 | return ret; | |
746 | } | |
747 | ||
fbdeb5ec MD |
748 | static void *tracepoint_remove_probe(const char *name, void (*probe)(void), |
749 | void *data) | |
f99be407 PMF |
750 | { |
751 | struct tracepoint_entry *entry; | |
752 | void *old; | |
753 | ||
754 | entry = get_tracepoint(name); | |
755 | if (!entry) | |
756 | return ERR_PTR(-ENOENT); | |
9dec086e | 757 | old = tracepoint_entry_remove_probe(entry, probe, data); |
f99be407 PMF |
758 | if (IS_ERR(old)) |
759 | return old; | |
760 | if (!entry->refcount) | |
761 | remove_tracepoint(entry); | |
762 | return old; | |
763 | } | |
764 | ||
765 | /** | |
766 | * tracepoint_probe_unregister - Disconnect a probe from a tracepoint | |
767 | * @name: tracepoint name | |
768 | * @probe: probe function pointer | |
9dec086e | 769 | * @probe: probe data pointer |
f99be407 | 770 | */ |
fbdeb5ec MD |
771 | int __tracepoint_probe_unregister(const char *name, void (*probe)(void), |
772 | void *data) | |
f99be407 PMF |
773 | { |
774 | void *old; | |
8792fbae | 775 | int ret = 0; |
f99be407 | 776 | |
05780d81 MD |
777 | DBG("Un-registering probe from tracepoint %s", name); |
778 | ||
8792fbae | 779 | pthread_mutex_lock(&tracepoint_mutex); |
9dec086e | 780 | old = tracepoint_remove_probe(name, probe, data); |
8792fbae MD |
781 | if (IS_ERR(old)) { |
782 | ret = PTR_ERR(old); | |
783 | goto end; | |
784 | } | |
3469bbbe | 785 | tracepoint_sync_callsites(name); |
f99be407 | 786 | release_probes(old); |
8792fbae MD |
787 | end: |
788 | pthread_mutex_unlock(&tracepoint_mutex); | |
789 | return ret; | |
f99be407 | 790 | } |
f99be407 | 791 | |
baa1e0bc MD |
792 | /* |
793 | * Caller needs to invoke __tracepoint_probe_release_queue() after | |
794 | * calling __tracepoint_probe_unregister_queue_release() one or multiple | |
795 | * times to ensure it does not leak memory. | |
796 | */ | |
797 | int __tracepoint_probe_unregister_queue_release(const char *name, | |
798 | void (*probe)(void), void *data) | |
799 | { | |
800 | void *old; | |
801 | int ret = 0; | |
802 | ||
803 | DBG("Un-registering probe from tracepoint %s. Queuing release.", name); | |
804 | ||
805 | pthread_mutex_lock(&tracepoint_mutex); | |
806 | old = tracepoint_remove_probe(name, probe, data); | |
807 | if (IS_ERR(old)) { | |
808 | ret = PTR_ERR(old); | |
809 | goto end; | |
810 | } | |
811 | tracepoint_sync_callsites(name); | |
812 | tracepoint_release_queue_add_old_probes(old); | |
813 | end: | |
814 | pthread_mutex_unlock(&tracepoint_mutex); | |
815 | return ret; | |
816 | } | |
817 | ||
818 | void __tracepoint_probe_prune_release_queue(void) | |
819 | { | |
820 | CDS_LIST_HEAD(release_probes); | |
821 | struct tp_probes *pos, *next; | |
822 | ||
823 | DBG("Release queue of unregistered tracepoint probes."); | |
824 | ||
825 | pthread_mutex_lock(&tracepoint_mutex); | |
826 | if (!release_queue_need_update) | |
827 | goto end; | |
828 | if (!cds_list_empty(&release_queue)) | |
829 | cds_list_replace_init(&release_queue, &release_probes); | |
830 | release_queue_need_update = 0; | |
831 | ||
832 | /* Wait for grace period between all sync_callsites and free. */ | |
10544ee8 | 833 | lttng_ust_synchronize_trace(); |
baa1e0bc MD |
834 | |
835 | cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) { | |
836 | cds_list_del(&pos->u.list); | |
837 | free(pos); | |
838 | } | |
839 | end: | |
840 | pthread_mutex_unlock(&tracepoint_mutex); | |
841 | } | |
842 | ||
f99be407 PMF |
843 | static void tracepoint_add_old_probes(void *old) |
844 | { | |
845 | need_update = 1; | |
846 | if (old) { | |
b728d87e | 847 | struct tp_probes *tp_probes = caa_container_of(old, |
f99be407 | 848 | struct tp_probes, probes[0]); |
0222e121 | 849 | cds_list_add(&tp_probes->u.list, &old_probes); |
f99be407 PMF |
850 | } |
851 | } | |
852 | ||
853 | /** | |
854 | * tracepoint_probe_register_noupdate - register a probe but not connect | |
855 | * @name: tracepoint name | |
856 | * @probe: probe handler | |
857 | * | |
858 | * caller must call tracepoint_probe_update_all() | |
859 | */ | |
fbdeb5ec | 860 | int tracepoint_probe_register_noupdate(const char *name, void (*probe)(void), |
67e5f391 | 861 | void *data, const char *signature) |
f99be407 PMF |
862 | { |
863 | void *old; | |
8792fbae | 864 | int ret = 0; |
f99be407 | 865 | |
8792fbae | 866 | pthread_mutex_lock(&tracepoint_mutex); |
67e5f391 | 867 | old = tracepoint_add_probe(name, probe, data, signature); |
f99be407 | 868 | if (IS_ERR(old)) { |
8792fbae MD |
869 | ret = PTR_ERR(old); |
870 | goto end; | |
f99be407 PMF |
871 | } |
872 | tracepoint_add_old_probes(old); | |
8792fbae MD |
873 | end: |
874 | pthread_mutex_unlock(&tracepoint_mutex); | |
875 | return ret; | |
f99be407 | 876 | } |
f99be407 PMF |
877 | |
878 | /** | |
879 | * tracepoint_probe_unregister_noupdate - remove a probe but not disconnect | |
880 | * @name: tracepoint name | |
881 | * @probe: probe function pointer | |
882 | * | |
883 | * caller must call tracepoint_probe_update_all() | |
8792fbae | 884 | * Called with the tracepoint mutex held. |
f99be407 | 885 | */ |
fbdeb5ec | 886 | int tracepoint_probe_unregister_noupdate(const char *name, void (*probe)(void), |
9dec086e | 887 | void *data) |
f99be407 PMF |
888 | { |
889 | void *old; | |
8792fbae | 890 | int ret = 0; |
f99be407 | 891 | |
05780d81 MD |
892 | DBG("Un-registering probe from tracepoint %s", name); |
893 | ||
8792fbae | 894 | pthread_mutex_lock(&tracepoint_mutex); |
9dec086e | 895 | old = tracepoint_remove_probe(name, probe, data); |
f99be407 | 896 | if (IS_ERR(old)) { |
8792fbae MD |
897 | ret = PTR_ERR(old); |
898 | goto end; | |
f99be407 PMF |
899 | } |
900 | tracepoint_add_old_probes(old); | |
8792fbae MD |
901 | end: |
902 | pthread_mutex_unlock(&tracepoint_mutex); | |
903 | return ret; | |
f99be407 | 904 | } |
f99be407 PMF |
905 | |
906 | /** | |
907 | * tracepoint_probe_update_all - update tracepoints | |
908 | */ | |
909 | void tracepoint_probe_update_all(void) | |
910 | { | |
0222e121 | 911 | CDS_LIST_HEAD(release_probes); |
f99be407 PMF |
912 | struct tp_probes *pos, *next; |
913 | ||
8792fbae | 914 | pthread_mutex_lock(&tracepoint_mutex); |
f99be407 | 915 | if (!need_update) { |
8792fbae | 916 | goto end; |
f99be407 | 917 | } |
0222e121 MD |
918 | if (!cds_list_empty(&old_probes)) |
919 | cds_list_replace_init(&old_probes, &release_probes); | |
f99be407 | 920 | need_update = 0; |
f99be407 PMF |
921 | |
922 | tracepoint_update_probes(); | |
baa1e0bc | 923 | /* Wait for grace period between update_probes and free. */ |
10544ee8 | 924 | lttng_ust_synchronize_trace(); |
0222e121 MD |
925 | cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) { |
926 | cds_list_del(&pos->u.list); | |
909bc43f | 927 | free(pos); |
f99be407 | 928 | } |
8792fbae MD |
929 | end: |
930 | pthread_mutex_unlock(&tracepoint_mutex); | |
f99be407 | 931 | } |
f99be407 | 932 | |
1a206094 | 933 | void tracepoint_set_new_tracepoint_cb(void (*cb)(struct lttng_ust_tracepoint *)) |
474d745f PMF |
934 | { |
935 | new_tracepoint_cb = cb; | |
936 | } | |
f99be407 | 937 | |
1a206094 SM |
938 | static void new_tracepoints(struct lttng_ust_tracepoint * const *start, |
939 | struct lttng_ust_tracepoint * const *end) | |
f99be407 | 940 | { |
f218ff28 | 941 | if (new_tracepoint_cb) { |
1a206094 | 942 | struct lttng_ust_tracepoint * const *t; |
f08ebbe2 | 943 | |
b27f8e75 | 944 | for (t = start; t < end; t++) { |
f08ebbe2 MD |
945 | if (*t) |
946 | new_tracepoint_cb(*t); | |
474d745f PMF |
947 | } |
948 | } | |
f99be407 | 949 | } |
f99be407 | 950 | |
10544ee8 MD |
951 | /* |
952 | * tracepoint_{un,}register_lib is meant to be looked up by instrumented | |
953 | * applications through dlsym(). If found, those can register their | |
954 | * tracepoints, else those tracepoints will not be available for | |
955 | * tracing. The number at the end of those symbols acts as a major | |
956 | * version for tracepoints. | |
957 | * | |
958 | * Older instrumented applications should still work with newer | |
959 | * liblttng-ust, but it is fine that instrumented applications compiled | |
960 | * against recent liblttng-ust headers require a recent liblttng-ust | |
961 | * runtime for those tracepoints to be taken into account. | |
962 | */ | |
963 | int tracepoint_register_lib2(struct lttng_ust_tracepoint * const *tracepoints_start, | |
964 | int tracepoints_count) | |
474d745f | 965 | { |
b467f7a7 | 966 | struct tracepoint_lib *pl, *iter; |
474d745f | 967 | |
edaa1431 MD |
968 | init_tracepoint(); |
969 | ||
1dba3e6c | 970 | pl = (struct tracepoint_lib *) zmalloc(sizeof(struct tracepoint_lib)); |
d6297168 MD |
971 | if (!pl) { |
972 | PERROR("Unable to register tracepoint lib"); | |
973 | return -1; | |
974 | } | |
474d745f PMF |
975 | pl->tracepoints_start = tracepoints_start; |
976 | pl->tracepoints_count = tracepoints_count; | |
3469bbbe | 977 | CDS_INIT_LIST_HEAD(&pl->callsites); |
474d745f | 978 | |
8792fbae | 979 | pthread_mutex_lock(&tracepoint_mutex); |
b467f7a7 MD |
980 | /* |
981 | * We sort the libs by struct lib pointer address. | |
982 | */ | |
983 | cds_list_for_each_entry_reverse(iter, &libs, list) { | |
984 | BUG_ON(iter == pl); /* Should never be in the list twice */ | |
985 | if (iter < pl) { | |
986 | /* We belong to the location right after iter. */ | |
987 | cds_list_add(&pl->list, &iter->list); | |
988 | goto lib_added; | |
989 | } | |
990 | } | |
991 | /* We should be added at the head of the list */ | |
0222e121 | 992 | cds_list_add(&pl->list, &libs); |
b467f7a7 | 993 | lib_added: |
474d745f | 994 | new_tracepoints(tracepoints_start, tracepoints_start + tracepoints_count); |
3469bbbe | 995 | lib_register_callsites(pl); |
5da10905 | 996 | lib_update_tracepoints(pl); |
8792fbae | 997 | pthread_mutex_unlock(&tracepoint_mutex); |
474d745f | 998 | |
1fcf7ad7 MD |
999 | DBG("just registered a tracepoints section from %p and having %d tracepoints", |
1000 | tracepoints_start, tracepoints_count); | |
05780d81 MD |
1001 | if (ust_debug()) { |
1002 | int i; | |
1003 | ||
1004 | for (i = 0; i < tracepoints_count; i++) { | |
1005 | DBG("registered tracepoint: %s", tracepoints_start[i]->name); | |
1006 | } | |
1007 | } | |
9dec086e | 1008 | |
474d745f PMF |
1009 | return 0; |
1010 | } | |
1011 | ||
10544ee8 MD |
1012 | /* Exposed for backward compatibility with old instrumented applications. */ |
1013 | int tracepoint_register_lib(struct lttng_ust_tracepoint * const *tracepoints_start, | |
1014 | int tracepoints_count) | |
1015 | { | |
1016 | lttng_ust_tracepoint_set_v1_used(); | |
1017 | return tracepoint_register_lib2(tracepoints_start, tracepoints_count); | |
1018 | } | |
1019 | ||
1020 | int tracepoint_unregister_lib2(struct lttng_ust_tracepoint * const *tracepoints_start) | |
474d745f | 1021 | { |
24b6668c PMF |
1022 | struct tracepoint_lib *lib; |
1023 | ||
8792fbae | 1024 | pthread_mutex_lock(&tracepoint_mutex); |
0222e121 | 1025 | cds_list_for_each_entry(lib, &libs, list) { |
3469bbbe MD |
1026 | if (lib->tracepoints_start != tracepoints_start) |
1027 | continue; | |
1622ba22 | 1028 | |
3469bbbe MD |
1029 | cds_list_del(&lib->list); |
1030 | /* | |
8a7ad54b IJ |
1031 | * Unregistering a callsite also decreases the |
1032 | * callsite reference count of the corresponding | |
1033 | * tracepoint, and disables the tracepoint if | |
1034 | * the reference count drops to zero. | |
3469bbbe | 1035 | */ |
3469bbbe MD |
1036 | lib_unregister_callsites(lib); |
1037 | DBG("just unregistered a tracepoints section from %p", | |
1038 | lib->tracepoints_start); | |
1039 | free(lib); | |
1040 | break; | |
24b6668c | 1041 | } |
8792fbae | 1042 | pthread_mutex_unlock(&tracepoint_mutex); |
474d745f PMF |
1043 | return 0; |
1044 | } | |
b27f8e75 | 1045 | |
10544ee8 MD |
1046 | /* Exposed for backward compatibility with old instrumented applications. */ |
1047 | int tracepoint_unregister_lib(struct lttng_ust_tracepoint * const *tracepoints_start) | |
1048 | { | |
1049 | lttng_ust_tracepoint_set_v1_used(); | |
1050 | return tracepoint_unregister_lib2(tracepoints_start); | |
1051 | } | |
1052 | ||
5517d34d MD |
1053 | /* |
1054 | * Report in debug message whether the compiler correctly supports weak | |
1055 | * hidden symbols. This test checks that the address associated with two | |
1056 | * weak symbols with hidden visibility is the same when declared within | |
1057 | * two compile units part of the same module. | |
1058 | */ | |
1059 | static void check_weak_hidden(void) | |
1060 | { | |
b0e63efd MD |
1061 | DBG("Your compiler treats weak symbols with hidden visibility for integer objects as %s between compile units part of the same module.", |
1062 | &__tracepoint_test_symbol1 == lttng_ust_tp_check_weak_hidden1() ? | |
1063 | "SAME address" : | |
1064 | "DIFFERENT addresses"); | |
1065 | DBG("Your compiler treats weak symbols with hidden visibility for pointer objects as %s between compile units part of the same module.", | |
1066 | &__tracepoint_test_symbol2 == lttng_ust_tp_check_weak_hidden2() ? | |
1067 | "SAME address" : | |
1068 | "DIFFERENT addresses"); | |
1069 | DBG("Your compiler treats weak symbols with hidden visibility for 24-byte structure objects as %s between compile units part of the same module.", | |
1070 | &__tracepoint_test_symbol3 == lttng_ust_tp_check_weak_hidden3() ? | |
1071 | "SAME address" : | |
1072 | "DIFFERENT addresses"); | |
5517d34d MD |
1073 | } |
1074 | ||
edaa1431 | 1075 | void init_tracepoint(void) |
b27f8e75 | 1076 | { |
edaa1431 MD |
1077 | if (uatomic_xchg(&initialized, 1) == 1) |
1078 | return; | |
5e96a467 | 1079 | init_usterr(); |
5517d34d | 1080 | check_weak_hidden(); |
b27f8e75 MD |
1081 | } |
1082 | ||
edaa1431 | 1083 | void exit_tracepoint(void) |
b27f8e75 | 1084 | { |
17dfb34b | 1085 | initialized = 0; |
b27f8e75 | 1086 | } |
40b2b5a4 MD |
1087 | |
1088 | /* | |
1089 | * Create the wrapper symbols. | |
1090 | */ | |
10544ee8 MD |
1091 | #undef tp_rcu_read_lock |
1092 | #undef tp_rcu_read_unlock | |
1093 | #undef tp_rcu_dereference | |
40b2b5a4 | 1094 | |
10544ee8 | 1095 | void tp_rcu_read_lock(void) |
40b2b5a4 | 1096 | { |
10544ee8 | 1097 | lttng_ust_urcu_read_lock(); |
40b2b5a4 MD |
1098 | } |
1099 | ||
10544ee8 | 1100 | void tp_rcu_read_unlock(void) |
40b2b5a4 | 1101 | { |
10544ee8 | 1102 | lttng_ust_urcu_read_unlock(); |
40b2b5a4 MD |
1103 | } |
1104 | ||
10544ee8 | 1105 | void *tp_rcu_dereference_sym(void *p) |
40b2b5a4 | 1106 | { |
10544ee8 | 1107 | return lttng_ust_rcu_dereference(p); |
40b2b5a4 | 1108 | } |
0fd0de10 FD |
1109 | |
1110 | /* | |
1111 | * Programs that have threads that survive after they exit, and therefore call | |
1112 | * library destructors, should disable the tracepoint destructors by calling | |
1113 | * tp_disable_destructors(). This will leak the tracepoint | |
1114 | * instrumentation library shared object, leaving its teardown to the operating | |
1115 | * system process teardown. | |
1116 | * | |
1117 | * To access and/or modify this value, users need to use a combination of | |
1118 | * dlopen(3) and dlsym(3) to get an handle on the | |
1119 | * tp_disable_destructors and tp_get_destructors_state symbols below. | |
1120 | */ | |
1121 | void tp_disable_destructors(void) | |
1122 | { | |
1123 | uatomic_set(&tracepoint_destructors_state, 0); | |
1124 | } | |
1125 | ||
1126 | /* | |
1127 | * Returns 1 if the destructors are enabled and should be executed. | |
1128 | * Returns 0 if the destructors are disabled. | |
1129 | */ | |
1130 | int tp_get_destructors_state(void) | |
1131 | { | |
1132 | return uatomic_read(&tracepoint_destructors_state); | |
1133 | } | |
10544ee8 MD |
1134 | |
1135 | void lttng_ust_synchronize_trace(void) | |
1136 | { | |
1137 | lttng_ust_urcu_synchronize_rcu(); | |
1138 | /* | |
1139 | * For legacy tracepoint instrumentation, also wait for urcu-bp | |
1140 | * grace period. | |
1141 | */ | |
1142 | if (lttng_ust_liburcu_bp_synchronize_rcu) | |
1143 | lttng_ust_liburcu_bp_synchronize_rcu(); | |
1144 | } | |
1145 | ||
1146 | /* | |
1147 | * Create the wrapper symbols for legacy v1 API. | |
1148 | */ | |
1149 | void tp_rcu_read_lock_bp(void) | |
1150 | { | |
1151 | lttng_ust_urcu_read_lock(); | |
1152 | } | |
1153 | ||
1154 | void tp_rcu_read_unlock_bp(void) | |
1155 | { | |
1156 | lttng_ust_urcu_read_unlock(); | |
1157 | } | |
1158 | ||
1159 | void *tp_rcu_dereference_sym_bp(void *p) | |
1160 | { | |
1161 | return lttng_ust_rcu_dereference(p); | |
1162 | } |