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