Commit | Line | Data |
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f99be407 | 1 | /* |
c0c0989a MJ |
2 | * SPDX-License-Identifier: LGPL-2.1-only |
3 | * | |
b27f8e75 | 4 | * Copyright (C) 2008-2011 Mathieu Desnoyers |
1f8b0dff | 5 | * Copyright (C) 2009 Pierre-Marc Fournier |
f99be407 | 6 | * |
1f8b0dff | 7 | * Ported to userspace by Pierre-Marc Fournier. |
f99be407 | 8 | */ |
1f8b0dff | 9 | |
b0c4126f | 10 | #define _LGPL_SOURCE |
474d745f | 11 | #include <errno.h> |
b728d87e MD |
12 | #include <stdint.h> |
13 | #include <stddef.h> | |
33661f97 | 14 | #include <stdio.h> |
44c72f10 | 15 | |
b728d87e | 16 | #include <urcu/arch.h> |
10544ee8 | 17 | #include <lttng/urcu/urcu-ust.h> |
10c56168 | 18 | #include <urcu/hlist.h> |
edaa1431 | 19 | #include <urcu/uatomic.h> |
b728d87e | 20 | #include <urcu/compiler.h> |
c082d14b | 21 | #include <urcu/system.h> |
44c72f10 MD |
22 | |
23 | #include <lttng/tracepoint.h> | |
fd17d7ce | 24 | #include <lttng/ust-abi.h> /* for LTTNG_UST_ABI_SYM_NAME_LEN */ |
44c72f10 MD |
25 | |
26 | #include <usterr-signal-safe.h> | |
864a1eda | 27 | #include <ust-helper.h> |
474d745f | 28 | |
23c8854a | 29 | #include "tracepoint-internal.h" |
7dd08bec | 30 | #include "lttng-tracer-core.h" |
596c4223 | 31 | #include "jhash.h" |
8f3f8c99 | 32 | #include "error.h" |
b0c4126f | 33 | |
5517d34d | 34 | /* Test compiler support for weak symbols with hidden visibility. */ |
b0e63efd MD |
35 | int __tracepoint_test_symbol1 __attribute__((weak, visibility("hidden"))); |
36 | void *__tracepoint_test_symbol2 __attribute__((weak, visibility("hidden"))); | |
37 | struct { | |
38 | char a[24]; | |
39 | } __tracepoint_test_symbol3 __attribute__((weak, visibility("hidden"))); | |
5517d34d | 40 | |
f99be407 PMF |
41 | /* Set to 1 to enable tracepoint debug output */ |
42 | static const int tracepoint_debug; | |
b27f8e75 | 43 | static int initialized; |
0fd0de10 FD |
44 | |
45 | /* | |
46 | * If tracepoint_destructors_state = 1, tracepoint destructors are | |
47 | * enabled. They are disabled otherwise. | |
48 | */ | |
49 | static int tracepoint_destructors_state = 1; | |
50 | ||
1a206094 | 51 | static void (*new_tracepoint_cb)(struct lttng_ust_tracepoint *); |
f99be407 | 52 | |
8792fbae MD |
53 | /* |
54 | * tracepoint_mutex nests inside UST mutex. | |
55 | * | |
56 | * Note about interaction with fork/clone: UST does not hold the | |
57 | * tracepoint mutex across fork/clone because it is either: | |
58 | * - nested within UST mutex, in which case holding the UST mutex across | |
59 | * fork/clone suffice, | |
60 | * - taken by a library constructor, which should never race with a | |
61 | * fork/clone if the application is expected to continue running with | |
62 | * the same memory layout (no following exec()). | |
63 | */ | |
64 | static pthread_mutex_t tracepoint_mutex = PTHREAD_MUTEX_INITIALIZER; | |
65 | ||
efa2c591 MD |
66 | /* |
67 | * libraries that contain tracepoints (struct tracepoint_lib). | |
8792fbae | 68 | * Protected by tracepoint mutex. |
efa2c591 | 69 | */ |
0222e121 | 70 | static CDS_LIST_HEAD(libs); |
474d745f | 71 | |
f99be407 | 72 | /* |
8792fbae | 73 | * The tracepoint mutex protects the library tracepoints, the hash table, and |
17dfb34b | 74 | * the library list. |
8792fbae | 75 | * All calls to the tracepoint API must be protected by the tracepoint mutex, |
17dfb34b | 76 | * excepts calls to tracepoint_register_lib and |
8792fbae | 77 | * tracepoint_unregister_lib, which take the tracepoint mutex themselves. |
f99be407 | 78 | */ |
f99be407 PMF |
79 | |
80 | /* | |
81 | * Tracepoint hash table, containing the active tracepoints. | |
8792fbae | 82 | * Protected by tracepoint mutex. |
f99be407 | 83 | */ |
814f7df1 | 84 | #define TRACEPOINT_HASH_BITS 12 |
f99be407 | 85 | #define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS) |
10c56168 | 86 | static struct cds_hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE]; |
f99be407 | 87 | |
b27f8e75 MD |
88 | static CDS_LIST_HEAD(old_probes); |
89 | static int need_update; | |
90 | ||
baa1e0bc MD |
91 | static CDS_LIST_HEAD(release_queue); |
92 | static int release_queue_need_update; | |
93 | ||
f99be407 PMF |
94 | /* |
95 | * Note about RCU : | |
96 | * It is used to to delay the free of multiple probes array until a quiescent | |
97 | * state is reached. | |
8792fbae | 98 | * Tracepoint entries modifications are protected by the tracepoint mutex. |
f99be407 PMF |
99 | */ |
100 | struct tracepoint_entry { | |
10c56168 | 101 | struct cds_hlist_node hlist; |
1a206094 | 102 | struct lttng_ust_tracepoint_probe *probes; |
f99be407 | 103 | int refcount; /* Number of times armed. 0 if disarmed. */ |
8a7ad54b | 104 | int callsite_refcount; /* how many libs use this tracepoint */ |
2c05c691 FD |
105 | char *signature; |
106 | char *name; | |
f99be407 PMF |
107 | }; |
108 | ||
109 | struct tp_probes { | |
110 | union { | |
0222e121 | 111 | struct cds_list_head list; |
ade7037b MD |
112 | /* Field below only used for call_rcu scheme */ |
113 | /* struct rcu_head head; */ | |
f99be407 | 114 | } u; |
1a206094 | 115 | struct lttng_ust_tracepoint_probe probes[0]; |
f99be407 PMF |
116 | }; |
117 | ||
3469bbbe MD |
118 | /* |
119 | * Callsite hash table, containing the tracepoint call sites. | |
120 | * Protected by tracepoint mutex. | |
121 | */ | |
122 | #define CALLSITE_HASH_BITS 12 | |
123 | #define CALLSITE_TABLE_SIZE (1 << CALLSITE_HASH_BITS) | |
124 | static struct cds_hlist_head callsite_table[CALLSITE_TABLE_SIZE]; | |
125 | ||
126 | struct callsite_entry { | |
127 | struct cds_hlist_node hlist; /* hash table node */ | |
128 | struct cds_list_head node; /* lib list of callsites node */ | |
1a206094 | 129 | struct lttng_ust_tracepoint *tp; |
2c05c691 | 130 | bool tp_entry_callsite_ref; /* Has a tp_entry took a ref on this callsite */ |
3469bbbe MD |
131 | }; |
132 | ||
5e6df7ea | 133 | /* coverity[+alloc] */ |
efa2c591 | 134 | static void *allocate_probes(int count) |
f99be407 | 135 | { |
1a206094 SM |
136 | struct tp_probes *p = |
137 | zmalloc(count * sizeof(struct lttng_ust_tracepoint_probe) | |
138 | + sizeof(struct tp_probes)); | |
f99be407 PMF |
139 | return p == NULL ? NULL : p->probes; |
140 | } | |
141 | ||
5e6df7ea | 142 | /* coverity[+free : arg-0] */ |
efa2c591 | 143 | static void release_probes(void *old) |
f99be407 PMF |
144 | { |
145 | if (old) { | |
b728d87e | 146 | struct tp_probes *tp_probes = caa_container_of(old, |
f99be407 | 147 | struct tp_probes, probes[0]); |
b653ddc1 | 148 | lttng_ust_urcu_synchronize_rcu(); |
909bc43f | 149 | free(tp_probes); |
f99be407 PMF |
150 | } |
151 | } | |
152 | ||
153 | static void debug_print_probes(struct tracepoint_entry *entry) | |
154 | { | |
155 | int i; | |
156 | ||
9dec086e | 157 | if (!tracepoint_debug || !entry->probes) |
f99be407 PMF |
158 | return; |
159 | ||
9dec086e NC |
160 | for (i = 0; entry->probes[i].func; i++) |
161 | DBG("Probe %d : %p", i, entry->probes[i].func); | |
f99be407 PMF |
162 | } |
163 | ||
164 | static void * | |
9dec086e | 165 | tracepoint_entry_add_probe(struct tracepoint_entry *entry, |
fbdeb5ec | 166 | void (*probe)(void), void *data) |
f99be407 PMF |
167 | { |
168 | int nr_probes = 0; | |
1a206094 | 169 | struct lttng_ust_tracepoint_probe *old, *new; |
f99be407 | 170 | |
d7509147 MD |
171 | if (!probe) { |
172 | WARN_ON(1); | |
173 | return ERR_PTR(-EINVAL); | |
174 | } | |
f99be407 | 175 | debug_print_probes(entry); |
9dec086e | 176 | old = entry->probes; |
f99be407 PMF |
177 | if (old) { |
178 | /* (N -> N+1), (N != 0, 1) probes */ | |
9dec086e NC |
179 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) |
180 | if (old[nr_probes].func == probe && | |
181 | old[nr_probes].data == data) | |
f99be407 PMF |
182 | return ERR_PTR(-EEXIST); |
183 | } | |
184 | /* + 2 : one for new probe, one for NULL func */ | |
185 | new = allocate_probes(nr_probes + 2); | |
186 | if (new == NULL) | |
187 | return ERR_PTR(-ENOMEM); | |
188 | if (old) | |
1a206094 SM |
189 | memcpy(new, old, |
190 | nr_probes * sizeof(struct lttng_ust_tracepoint_probe)); | |
9dec086e NC |
191 | new[nr_probes].func = probe; |
192 | new[nr_probes].data = data; | |
193 | new[nr_probes + 1].func = NULL; | |
f99be407 | 194 | entry->refcount = nr_probes + 1; |
9dec086e | 195 | entry->probes = new; |
f99be407 PMF |
196 | debug_print_probes(entry); |
197 | return old; | |
198 | } | |
199 | ||
200 | static void * | |
fbdeb5ec MD |
201 | tracepoint_entry_remove_probe(struct tracepoint_entry *entry, |
202 | void (*probe)(void), void *data) | |
f99be407 PMF |
203 | { |
204 | int nr_probes = 0, nr_del = 0, i; | |
1a206094 | 205 | struct lttng_ust_tracepoint_probe *old, *new; |
f99be407 | 206 | |
9dec086e | 207 | old = entry->probes; |
f99be407 PMF |
208 | |
209 | if (!old) | |
210 | return ERR_PTR(-ENOENT); | |
211 | ||
212 | debug_print_probes(entry); | |
213 | /* (N -> M), (N > 1, M >= 0) probes */ | |
956c6fab MD |
214 | if (probe) { |
215 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) { | |
216 | if (old[nr_probes].func == probe && | |
217 | old[nr_probes].data == data) | |
218 | nr_del++; | |
219 | } | |
f99be407 PMF |
220 | } |
221 | ||
222 | if (nr_probes - nr_del == 0) { | |
223 | /* N -> 0, (N > 1) */ | |
9dec086e | 224 | entry->probes = NULL; |
f99be407 PMF |
225 | entry->refcount = 0; |
226 | debug_print_probes(entry); | |
227 | return old; | |
228 | } else { | |
229 | int j = 0; | |
230 | /* N -> M, (N > 1, M > 0) */ | |
231 | /* + 1 for NULL */ | |
232 | new = allocate_probes(nr_probes - nr_del + 1); | |
233 | if (new == NULL) | |
234 | return ERR_PTR(-ENOMEM); | |
9dec086e | 235 | for (i = 0; old[i].func; i++) |
956c6fab | 236 | if (old[i].func != probe || old[i].data != data) |
f99be407 | 237 | new[j++] = old[i]; |
9dec086e | 238 | new[nr_probes - nr_del].func = NULL; |
f99be407 | 239 | entry->refcount = nr_probes - nr_del; |
9dec086e | 240 | entry->probes = new; |
f99be407 PMF |
241 | } |
242 | debug_print_probes(entry); | |
243 | return old; | |
244 | } | |
245 | ||
246 | /* | |
247 | * Get tracepoint if the tracepoint is present in the tracepoint hash table. | |
8792fbae | 248 | * Must be called with tracepoint mutex held. |
f99be407 PMF |
249 | * Returns NULL if not present. |
250 | */ | |
251 | static struct tracepoint_entry *get_tracepoint(const char *name) | |
252 | { | |
10c56168 DG |
253 | struct cds_hlist_head *head; |
254 | struct cds_hlist_node *node; | |
f99be407 | 255 | struct tracepoint_entry *e; |
ff412fb5 MD |
256 | size_t name_len = strlen(name); |
257 | uint32_t hash; | |
f99be407 | 258 | |
fd17d7ce MD |
259 | if (name_len > LTTNG_UST_ABI_SYM_NAME_LEN - 1) { |
260 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_ABI_SYM_NAME_LEN - 1); | |
261 | name_len = LTTNG_UST_ABI_SYM_NAME_LEN - 1; | |
ff412fb5 MD |
262 | } |
263 | hash = jhash(name, name_len, 0); | |
f99be407 | 264 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
10c56168 | 265 | cds_hlist_for_each_entry(e, node, head, hlist) { |
fd17d7ce | 266 | if (!strncmp(name, e->name, LTTNG_UST_ABI_SYM_NAME_LEN - 1)) |
f99be407 PMF |
267 | return e; |
268 | } | |
269 | return NULL; | |
270 | } | |
271 | ||
272 | /* | |
273 | * Add the tracepoint to the tracepoint hash table. Must be called with | |
8792fbae | 274 | * tracepoint mutex held. |
f99be407 | 275 | */ |
67e5f391 MD |
276 | static struct tracepoint_entry *add_tracepoint(const char *name, |
277 | const char *signature) | |
f99be407 | 278 | { |
10c56168 DG |
279 | struct cds_hlist_head *head; |
280 | struct cds_hlist_node *node; | |
f99be407 | 281 | struct tracepoint_entry *e; |
ff412fb5 | 282 | size_t name_len = strlen(name); |
2c05c691 FD |
283 | size_t sig_len = strlen(signature); |
284 | size_t sig_off, name_off; | |
ff412fb5 | 285 | uint32_t hash; |
f99be407 | 286 | |
fd17d7ce MD |
287 | if (name_len > LTTNG_UST_ABI_SYM_NAME_LEN - 1) { |
288 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_ABI_SYM_NAME_LEN - 1); | |
289 | name_len = LTTNG_UST_ABI_SYM_NAME_LEN - 1; | |
ff412fb5 MD |
290 | } |
291 | hash = jhash(name, name_len, 0); | |
f99be407 | 292 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
10c56168 | 293 | cds_hlist_for_each_entry(e, node, head, hlist) { |
fd17d7ce | 294 | if (!strncmp(name, e->name, LTTNG_UST_ABI_SYM_NAME_LEN - 1)) { |
c1f20530 | 295 | DBG("tracepoint %s busy", name); |
f99be407 PMF |
296 | return ERR_PTR(-EEXIST); /* Already there */ |
297 | } | |
298 | } | |
2c05c691 | 299 | |
f99be407 | 300 | /* |
2c05c691 FD |
301 | * Using zmalloc here to allocate a variable length elements: name and |
302 | * signature. Could cause some memory fragmentation if overused. | |
f99be407 | 303 | */ |
2c05c691 FD |
304 | name_off = sizeof(struct tracepoint_entry); |
305 | sig_off = name_off + name_len + 1; | |
306 | ||
307 | e = zmalloc(sizeof(struct tracepoint_entry) + name_len + 1 + sig_len + 1); | |
f99be407 PMF |
308 | if (!e) |
309 | return ERR_PTR(-ENOMEM); | |
2c05c691 FD |
310 | e->name = (char *) e + name_off; |
311 | memcpy(e->name, name, name_len + 1); | |
ff412fb5 | 312 | e->name[name_len] = '\0'; |
2c05c691 FD |
313 | |
314 | e->signature = (char *) e + sig_off; | |
315 | memcpy(e->signature, signature, sig_len + 1); | |
316 | e->signature[sig_len] = '\0'; | |
317 | ||
9dec086e | 318 | e->probes = NULL; |
f99be407 | 319 | e->refcount = 0; |
8a7ad54b | 320 | e->callsite_refcount = 0; |
2c05c691 | 321 | |
10c56168 | 322 | cds_hlist_add_head(&e->hlist, head); |
f99be407 PMF |
323 | return e; |
324 | } | |
325 | ||
326 | /* | |
327 | * Remove the tracepoint from the tracepoint hash table. Must be called with | |
8792fbae | 328 | * tracepoint mutex held. |
f99be407 | 329 | */ |
efa2c591 | 330 | static void remove_tracepoint(struct tracepoint_entry *e) |
f99be407 | 331 | { |
10c56168 | 332 | cds_hlist_del(&e->hlist); |
909bc43f | 333 | free(e); |
f99be407 PMF |
334 | } |
335 | ||
336 | /* | |
337 | * Sets the probe callback corresponding to one tracepoint. | |
338 | */ | |
339 | static void set_tracepoint(struct tracepoint_entry **entry, | |
1a206094 | 340 | struct lttng_ust_tracepoint *elem, int active) |
f99be407 | 341 | { |
fd17d7ce | 342 | WARN_ON(strncmp((*entry)->name, elem->name, LTTNG_UST_ABI_SYM_NAME_LEN - 1) != 0); |
67e5f391 MD |
343 | /* |
344 | * Check that signatures match before connecting a probe to a | |
345 | * tracepoint. Warn the user if they don't. | |
346 | */ | |
347 | if (strcmp(elem->signature, (*entry)->signature) != 0) { | |
348 | static int warned = 0; | |
349 | ||
350 | /* Only print once, don't flood console. */ | |
351 | if (!warned) { | |
352 | WARN("Tracepoint signature mismatch, not enabling one or more tracepoints. Ensure that the tracepoint probes prototypes match the application."); | |
353 | WARN("Tracepoint \"%s\" signatures: call: \"%s\" vs probe: \"%s\".", | |
354 | elem->name, elem->signature, (*entry)->signature); | |
355 | warned = 1; | |
356 | } | |
357 | /* Don't accept connecting non-matching signatures. */ | |
358 | return; | |
359 | } | |
f99be407 PMF |
360 | |
361 | /* | |
0222e121 | 362 | * rcu_assign_pointer has a cmm_smp_wmb() which makes sure that the new |
f99be407 PMF |
363 | * probe callbacks array is consistent before setting a pointer to it. |
364 | * This array is referenced by __DO_TRACE from | |
0222e121 | 365 | * include/linux/tracepoints.h. A matching cmm_smp_read_barrier_depends() |
f99be407 PMF |
366 | * is used. |
367 | */ | |
10544ee8 | 368 | lttng_ust_rcu_assign_pointer(elem->probes, (*entry)->probes); |
c082d14b | 369 | CMM_STORE_SHARED(elem->state, active); |
f99be407 PMF |
370 | } |
371 | ||
372 | /* | |
373 | * Disable a tracepoint and its probe callback. | |
374 | * Note: only waiting an RCU period after setting elem->call to the empty | |
375 | * function insures that the original callback is not used anymore. This insured | |
376 | * by preempt_disable around the call site. | |
377 | */ | |
1a206094 | 378 | static void disable_tracepoint(struct lttng_ust_tracepoint *elem) |
f99be407 | 379 | { |
c082d14b | 380 | CMM_STORE_SHARED(elem->state, 0); |
10544ee8 | 381 | lttng_ust_rcu_assign_pointer(elem->probes, NULL); |
f99be407 PMF |
382 | } |
383 | ||
33f8ed87 MD |
384 | /* |
385 | * Add the callsite to the callsite hash table. Must be called with | |
386 | * tracepoint mutex held. | |
387 | */ | |
1a206094 | 388 | static void add_callsite(struct tracepoint_lib * lib, struct lttng_ust_tracepoint *tp) |
33f8ed87 MD |
389 | { |
390 | struct cds_hlist_head *head; | |
391 | struct callsite_entry *e; | |
392 | const char *name = tp->name; | |
393 | size_t name_len = strlen(name); | |
394 | uint32_t hash; | |
8a7ad54b | 395 | struct tracepoint_entry *tp_entry; |
33f8ed87 | 396 | |
fd17d7ce MD |
397 | if (name_len > LTTNG_UST_ABI_SYM_NAME_LEN - 1) { |
398 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_ABI_SYM_NAME_LEN - 1); | |
399 | name_len = LTTNG_UST_ABI_SYM_NAME_LEN - 1; | |
33f8ed87 MD |
400 | } |
401 | hash = jhash(name, name_len, 0); | |
402 | head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)]; | |
403 | e = zmalloc(sizeof(struct callsite_entry)); | |
d6297168 MD |
404 | if (!e) { |
405 | PERROR("Unable to add callsite for tracepoint \"%s\"", name); | |
406 | return; | |
407 | } | |
33f8ed87 MD |
408 | cds_hlist_add_head(&e->hlist, head); |
409 | e->tp = tp; | |
410 | cds_list_add(&e->node, &lib->callsites); | |
8a7ad54b IJ |
411 | |
412 | tp_entry = get_tracepoint(name); | |
413 | if (!tp_entry) | |
414 | return; | |
415 | tp_entry->callsite_refcount++; | |
2c05c691 | 416 | e->tp_entry_callsite_ref = true; |
33f8ed87 MD |
417 | } |
418 | ||
419 | /* | |
420 | * Remove the callsite from the callsite hash table and from lib | |
421 | * callsite list. Must be called with tracepoint mutex held. | |
422 | */ | |
423 | static void remove_callsite(struct callsite_entry *e) | |
424 | { | |
8a7ad54b IJ |
425 | struct tracepoint_entry *tp_entry; |
426 | ||
427 | tp_entry = get_tracepoint(e->tp->name); | |
428 | if (tp_entry) { | |
2c05c691 FD |
429 | if (e->tp_entry_callsite_ref) |
430 | tp_entry->callsite_refcount--; | |
8a7ad54b IJ |
431 | if (tp_entry->callsite_refcount == 0) |
432 | disable_tracepoint(e->tp); | |
433 | } | |
33f8ed87 MD |
434 | cds_hlist_del(&e->hlist); |
435 | cds_list_del(&e->node); | |
436 | free(e); | |
437 | } | |
438 | ||
3469bbbe MD |
439 | /* |
440 | * Enable/disable all callsites based on the state of a specific | |
441 | * tracepoint entry. | |
442 | * Must be called with tracepoint mutex held. | |
443 | */ | |
444 | static void tracepoint_sync_callsites(const char *name) | |
445 | { | |
446 | struct cds_hlist_head *head; | |
447 | struct cds_hlist_node *node; | |
448 | struct callsite_entry *e; | |
449 | size_t name_len = strlen(name); | |
450 | uint32_t hash; | |
451 | struct tracepoint_entry *tp_entry; | |
452 | ||
453 | tp_entry = get_tracepoint(name); | |
fd17d7ce MD |
454 | if (name_len > LTTNG_UST_ABI_SYM_NAME_LEN - 1) { |
455 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_ABI_SYM_NAME_LEN - 1); | |
456 | name_len = LTTNG_UST_ABI_SYM_NAME_LEN - 1; | |
3469bbbe MD |
457 | } |
458 | hash = jhash(name, name_len, 0); | |
459 | head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)]; | |
460 | cds_hlist_for_each_entry(e, node, head, hlist) { | |
1a206094 | 461 | struct lttng_ust_tracepoint *tp = e->tp; |
3469bbbe | 462 | |
fd17d7ce | 463 | if (strncmp(name, tp->name, LTTNG_UST_ABI_SYM_NAME_LEN - 1)) |
3469bbbe MD |
464 | continue; |
465 | if (tp_entry) { | |
2c05c691 FD |
466 | if (!e->tp_entry_callsite_ref) { |
467 | tp_entry->callsite_refcount++; | |
468 | e->tp_entry_callsite_ref = true; | |
469 | } | |
3469bbbe MD |
470 | set_tracepoint(&tp_entry, tp, |
471 | !!tp_entry->refcount); | |
472 | } else { | |
473 | disable_tracepoint(tp); | |
2c05c691 | 474 | e->tp_entry_callsite_ref = false; |
3469bbbe MD |
475 | } |
476 | } | |
477 | } | |
478 | ||
f99be407 PMF |
479 | /** |
480 | * tracepoint_update_probe_range - Update a probe range | |
481 | * @begin: beginning of the range | |
482 | * @end: end of the range | |
483 | * | |
484 | * Updates the probe callback corresponding to a range of tracepoints. | |
485 | */ | |
b27f8e75 | 486 | static |
1a206094 SM |
487 | void tracepoint_update_probe_range(struct lttng_ust_tracepoint * const *begin, |
488 | struct lttng_ust_tracepoint * const *end) | |
f99be407 | 489 | { |
1a206094 | 490 | struct lttng_ust_tracepoint * const *iter; |
f99be407 PMF |
491 | struct tracepoint_entry *mark_entry; |
492 | ||
f99be407 | 493 | for (iter = begin; iter < end; iter++) { |
f08ebbe2 MD |
494 | if (!*iter) |
495 | continue; /* skip dummy */ | |
f218ff28 MD |
496 | if (!(*iter)->name) { |
497 | disable_tracepoint(*iter); | |
9dec086e NC |
498 | continue; |
499 | } | |
f218ff28 | 500 | mark_entry = get_tracepoint((*iter)->name); |
f99be407 | 501 | if (mark_entry) { |
f218ff28 | 502 | set_tracepoint(&mark_entry, *iter, |
f99be407 PMF |
503 | !!mark_entry->refcount); |
504 | } else { | |
f218ff28 | 505 | disable_tracepoint(*iter); |
f99be407 PMF |
506 | } |
507 | } | |
f99be407 PMF |
508 | } |
509 | ||
5da10905 | 510 | static void lib_update_tracepoints(struct tracepoint_lib *lib) |
772030fe | 511 | { |
5da10905 MD |
512 | tracepoint_update_probe_range(lib->tracepoints_start, |
513 | lib->tracepoints_start + lib->tracepoints_count); | |
772030fe PMF |
514 | } |
515 | ||
3469bbbe MD |
516 | static void lib_register_callsites(struct tracepoint_lib *lib) |
517 | { | |
1a206094 SM |
518 | struct lttng_ust_tracepoint * const *begin; |
519 | struct lttng_ust_tracepoint * const *end; | |
520 | struct lttng_ust_tracepoint * const *iter; | |
3469bbbe MD |
521 | |
522 | begin = lib->tracepoints_start; | |
523 | end = lib->tracepoints_start + lib->tracepoints_count; | |
524 | ||
525 | for (iter = begin; iter < end; iter++) { | |
526 | if (!*iter) | |
527 | continue; /* skip dummy */ | |
528 | if (!(*iter)->name) { | |
529 | continue; | |
530 | } | |
60d87029 | 531 | add_callsite(lib, *iter); |
3469bbbe MD |
532 | } |
533 | } | |
534 | ||
535 | static void lib_unregister_callsites(struct tracepoint_lib *lib) | |
536 | { | |
537 | struct callsite_entry *callsite, *tmp; | |
538 | ||
539 | cds_list_for_each_entry_safe(callsite, tmp, &lib->callsites, node) | |
540 | remove_callsite(callsite); | |
541 | } | |
542 | ||
f99be407 PMF |
543 | /* |
544 | * Update probes, removing the faulty probes. | |
545 | */ | |
546 | static void tracepoint_update_probes(void) | |
547 | { | |
5da10905 MD |
548 | struct tracepoint_lib *lib; |
549 | ||
b27f8e75 | 550 | /* tracepoints registered from libraries and executable. */ |
5da10905 MD |
551 | cds_list_for_each_entry(lib, &libs, list) |
552 | lib_update_tracepoints(lib); | |
f99be407 PMF |
553 | } |
554 | ||
1a206094 | 555 | static struct lttng_ust_tracepoint_probe * |
fbdeb5ec | 556 | tracepoint_add_probe(const char *name, void (*probe)(void), void *data, |
67e5f391 | 557 | const char *signature) |
f99be407 PMF |
558 | { |
559 | struct tracepoint_entry *entry; | |
1a206094 | 560 | struct lttng_ust_tracepoint_probe *old; |
f99be407 PMF |
561 | |
562 | entry = get_tracepoint(name); | |
2c05c691 FD |
563 | if (entry) { |
564 | if (strcmp(entry->signature, signature) != 0) { | |
565 | ERR("Tracepoint and probe signature do not match."); | |
566 | return ERR_PTR(-EINVAL); | |
567 | } | |
568 | } else { | |
67e5f391 | 569 | entry = add_tracepoint(name, signature); |
f99be407 | 570 | if (IS_ERR(entry)) |
1a206094 | 571 | return (struct lttng_ust_tracepoint_probe *)entry; |
f99be407 | 572 | } |
9dec086e | 573 | old = tracepoint_entry_add_probe(entry, probe, data); |
f99be407 PMF |
574 | if (IS_ERR(old) && !entry->refcount) |
575 | remove_tracepoint(entry); | |
576 | return old; | |
577 | } | |
578 | ||
baa1e0bc MD |
579 | static void tracepoint_release_queue_add_old_probes(void *old) |
580 | { | |
581 | release_queue_need_update = 1; | |
582 | if (old) { | |
583 | struct tp_probes *tp_probes = caa_container_of(old, | |
584 | struct tp_probes, probes[0]); | |
585 | cds_list_add(&tp_probes->u.list, &release_queue); | |
586 | } | |
587 | } | |
588 | ||
f99be407 | 589 | /** |
81614639 | 590 | * __tracepoint_probe_register - Connect a probe to a tracepoint |
f99be407 PMF |
591 | * @name: tracepoint name |
592 | * @probe: probe handler | |
593 | * | |
594 | * Returns 0 if ok, error value on error. | |
595 | * The probe address must at least be aligned on the architecture pointer size. | |
8792fbae | 596 | * Called with the tracepoint mutex held. |
f99be407 | 597 | */ |
fbdeb5ec MD |
598 | int __tracepoint_probe_register(const char *name, void (*probe)(void), |
599 | void *data, const char *signature) | |
f99be407 PMF |
600 | { |
601 | void *old; | |
8792fbae | 602 | int ret = 0; |
f99be407 | 603 | |
05780d81 MD |
604 | DBG("Registering probe to tracepoint %s", name); |
605 | ||
8792fbae | 606 | pthread_mutex_lock(&tracepoint_mutex); |
67e5f391 | 607 | old = tracepoint_add_probe(name, probe, data, signature); |
8792fbae MD |
608 | if (IS_ERR(old)) { |
609 | ret = PTR_ERR(old); | |
610 | goto end; | |
611 | } | |
f99be407 | 612 | |
3469bbbe | 613 | tracepoint_sync_callsites(name); |
f99be407 | 614 | release_probes(old); |
8792fbae MD |
615 | end: |
616 | pthread_mutex_unlock(&tracepoint_mutex); | |
617 | return ret; | |
f99be407 | 618 | } |
f99be407 | 619 | |
baa1e0bc MD |
620 | /* |
621 | * Caller needs to invoke __tracepoint_probe_release_queue() after | |
d10a2205 | 622 | * calling lttng_ust_tp_probe_register_queue_release() one or multiple |
baa1e0bc MD |
623 | * times to ensure it does not leak memory. |
624 | */ | |
d10a2205 | 625 | int lttng_ust_tp_probe_register_queue_release(const char *name, |
baa1e0bc MD |
626 | void (*probe)(void), void *data, const char *signature) |
627 | { | |
628 | void *old; | |
629 | int ret = 0; | |
630 | ||
631 | DBG("Registering probe to tracepoint %s. Queuing release.", name); | |
632 | ||
633 | pthread_mutex_lock(&tracepoint_mutex); | |
634 | old = tracepoint_add_probe(name, probe, data, signature); | |
635 | if (IS_ERR(old)) { | |
636 | ret = PTR_ERR(old); | |
637 | goto end; | |
638 | } | |
639 | ||
640 | tracepoint_sync_callsites(name); | |
641 | tracepoint_release_queue_add_old_probes(old); | |
642 | end: | |
643 | pthread_mutex_unlock(&tracepoint_mutex); | |
644 | return ret; | |
645 | } | |
646 | ||
fbdeb5ec MD |
647 | static void *tracepoint_remove_probe(const char *name, void (*probe)(void), |
648 | void *data) | |
f99be407 PMF |
649 | { |
650 | struct tracepoint_entry *entry; | |
651 | void *old; | |
652 | ||
653 | entry = get_tracepoint(name); | |
654 | if (!entry) | |
655 | return ERR_PTR(-ENOENT); | |
9dec086e | 656 | old = tracepoint_entry_remove_probe(entry, probe, data); |
f99be407 PMF |
657 | if (IS_ERR(old)) |
658 | return old; | |
659 | if (!entry->refcount) | |
660 | remove_tracepoint(entry); | |
661 | return old; | |
662 | } | |
663 | ||
664 | /** | |
665 | * tracepoint_probe_unregister - Disconnect a probe from a tracepoint | |
666 | * @name: tracepoint name | |
667 | * @probe: probe function pointer | |
9dec086e | 668 | * @probe: probe data pointer |
f99be407 | 669 | */ |
fbdeb5ec MD |
670 | int __tracepoint_probe_unregister(const char *name, void (*probe)(void), |
671 | void *data) | |
f99be407 PMF |
672 | { |
673 | void *old; | |
8792fbae | 674 | int ret = 0; |
f99be407 | 675 | |
05780d81 MD |
676 | DBG("Un-registering probe from tracepoint %s", name); |
677 | ||
8792fbae | 678 | pthread_mutex_lock(&tracepoint_mutex); |
9dec086e | 679 | old = tracepoint_remove_probe(name, probe, data); |
8792fbae MD |
680 | if (IS_ERR(old)) { |
681 | ret = PTR_ERR(old); | |
682 | goto end; | |
683 | } | |
3469bbbe | 684 | tracepoint_sync_callsites(name); |
f99be407 | 685 | release_probes(old); |
8792fbae MD |
686 | end: |
687 | pthread_mutex_unlock(&tracepoint_mutex); | |
688 | return ret; | |
f99be407 | 689 | } |
f99be407 | 690 | |
baa1e0bc MD |
691 | /* |
692 | * Caller needs to invoke __tracepoint_probe_release_queue() after | |
d10a2205 | 693 | * calling lttng_ust_tp_probe_unregister_queue_release() one or multiple |
baa1e0bc MD |
694 | * times to ensure it does not leak memory. |
695 | */ | |
d10a2205 | 696 | int lttng_ust_tp_probe_unregister_queue_release(const char *name, |
baa1e0bc MD |
697 | void (*probe)(void), void *data) |
698 | { | |
699 | void *old; | |
700 | int ret = 0; | |
701 | ||
702 | DBG("Un-registering probe from tracepoint %s. Queuing release.", name); | |
703 | ||
704 | pthread_mutex_lock(&tracepoint_mutex); | |
705 | old = tracepoint_remove_probe(name, probe, data); | |
706 | if (IS_ERR(old)) { | |
707 | ret = PTR_ERR(old); | |
708 | goto end; | |
709 | } | |
710 | tracepoint_sync_callsites(name); | |
711 | tracepoint_release_queue_add_old_probes(old); | |
712 | end: | |
713 | pthread_mutex_unlock(&tracepoint_mutex); | |
714 | return ret; | |
715 | } | |
716 | ||
d10a2205 | 717 | void lttng_ust_tp_probe_prune_release_queue(void) |
baa1e0bc MD |
718 | { |
719 | CDS_LIST_HEAD(release_probes); | |
720 | struct tp_probes *pos, *next; | |
721 | ||
722 | DBG("Release queue of unregistered tracepoint probes."); | |
723 | ||
724 | pthread_mutex_lock(&tracepoint_mutex); | |
725 | if (!release_queue_need_update) | |
726 | goto end; | |
727 | if (!cds_list_empty(&release_queue)) | |
728 | cds_list_replace_init(&release_queue, &release_probes); | |
729 | release_queue_need_update = 0; | |
730 | ||
731 | /* Wait for grace period between all sync_callsites and free. */ | |
b653ddc1 | 732 | lttng_ust_urcu_synchronize_rcu(); |
baa1e0bc MD |
733 | |
734 | cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) { | |
735 | cds_list_del(&pos->u.list); | |
736 | free(pos); | |
737 | } | |
738 | end: | |
739 | pthread_mutex_unlock(&tracepoint_mutex); | |
740 | } | |
741 | ||
f99be407 PMF |
742 | static void tracepoint_add_old_probes(void *old) |
743 | { | |
744 | need_update = 1; | |
745 | if (old) { | |
b728d87e | 746 | struct tp_probes *tp_probes = caa_container_of(old, |
f99be407 | 747 | struct tp_probes, probes[0]); |
0222e121 | 748 | cds_list_add(&tp_probes->u.list, &old_probes); |
f99be407 PMF |
749 | } |
750 | } | |
751 | ||
752 | /** | |
753 | * tracepoint_probe_register_noupdate - register a probe but not connect | |
754 | * @name: tracepoint name | |
755 | * @probe: probe handler | |
756 | * | |
757 | * caller must call tracepoint_probe_update_all() | |
758 | */ | |
fbdeb5ec | 759 | int tracepoint_probe_register_noupdate(const char *name, void (*probe)(void), |
67e5f391 | 760 | void *data, const char *signature) |
f99be407 PMF |
761 | { |
762 | void *old; | |
8792fbae | 763 | int ret = 0; |
f99be407 | 764 | |
8792fbae | 765 | pthread_mutex_lock(&tracepoint_mutex); |
67e5f391 | 766 | old = tracepoint_add_probe(name, probe, data, signature); |
f99be407 | 767 | if (IS_ERR(old)) { |
8792fbae MD |
768 | ret = PTR_ERR(old); |
769 | goto end; | |
f99be407 PMF |
770 | } |
771 | tracepoint_add_old_probes(old); | |
8792fbae MD |
772 | end: |
773 | pthread_mutex_unlock(&tracepoint_mutex); | |
774 | return ret; | |
f99be407 | 775 | } |
f99be407 PMF |
776 | |
777 | /** | |
778 | * tracepoint_probe_unregister_noupdate - remove a probe but not disconnect | |
779 | * @name: tracepoint name | |
780 | * @probe: probe function pointer | |
781 | * | |
782 | * caller must call tracepoint_probe_update_all() | |
8792fbae | 783 | * Called with the tracepoint mutex held. |
f99be407 | 784 | */ |
fbdeb5ec | 785 | int tracepoint_probe_unregister_noupdate(const char *name, void (*probe)(void), |
9dec086e | 786 | void *data) |
f99be407 PMF |
787 | { |
788 | void *old; | |
8792fbae | 789 | int ret = 0; |
f99be407 | 790 | |
05780d81 MD |
791 | DBG("Un-registering probe from tracepoint %s", name); |
792 | ||
8792fbae | 793 | pthread_mutex_lock(&tracepoint_mutex); |
9dec086e | 794 | old = tracepoint_remove_probe(name, probe, data); |
f99be407 | 795 | if (IS_ERR(old)) { |
8792fbae MD |
796 | ret = PTR_ERR(old); |
797 | goto end; | |
f99be407 PMF |
798 | } |
799 | tracepoint_add_old_probes(old); | |
8792fbae MD |
800 | end: |
801 | pthread_mutex_unlock(&tracepoint_mutex); | |
802 | return ret; | |
f99be407 | 803 | } |
f99be407 PMF |
804 | |
805 | /** | |
806 | * tracepoint_probe_update_all - update tracepoints | |
807 | */ | |
808 | void tracepoint_probe_update_all(void) | |
809 | { | |
0222e121 | 810 | CDS_LIST_HEAD(release_probes); |
f99be407 PMF |
811 | struct tp_probes *pos, *next; |
812 | ||
8792fbae | 813 | pthread_mutex_lock(&tracepoint_mutex); |
f99be407 | 814 | if (!need_update) { |
8792fbae | 815 | goto end; |
f99be407 | 816 | } |
0222e121 MD |
817 | if (!cds_list_empty(&old_probes)) |
818 | cds_list_replace_init(&old_probes, &release_probes); | |
f99be407 | 819 | need_update = 0; |
f99be407 PMF |
820 | |
821 | tracepoint_update_probes(); | |
baa1e0bc | 822 | /* Wait for grace period between update_probes and free. */ |
b653ddc1 | 823 | lttng_ust_urcu_synchronize_rcu(); |
0222e121 MD |
824 | cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) { |
825 | cds_list_del(&pos->u.list); | |
909bc43f | 826 | free(pos); |
f99be407 | 827 | } |
8792fbae MD |
828 | end: |
829 | pthread_mutex_unlock(&tracepoint_mutex); | |
f99be407 | 830 | } |
f99be407 | 831 | |
1a206094 SM |
832 | static void new_tracepoints(struct lttng_ust_tracepoint * const *start, |
833 | struct lttng_ust_tracepoint * const *end) | |
f99be407 | 834 | { |
f218ff28 | 835 | if (new_tracepoint_cb) { |
1a206094 | 836 | struct lttng_ust_tracepoint * const *t; |
f08ebbe2 | 837 | |
b27f8e75 | 838 | for (t = start; t < end; t++) { |
f08ebbe2 MD |
839 | if (*t) |
840 | new_tracepoint_cb(*t); | |
474d745f PMF |
841 | } |
842 | } | |
f99be407 | 843 | } |
f99be407 | 844 | |
10544ee8 MD |
845 | /* |
846 | * tracepoint_{un,}register_lib is meant to be looked up by instrumented | |
847 | * applications through dlsym(). If found, those can register their | |
848 | * tracepoints, else those tracepoints will not be available for | |
849 | * tracing. The number at the end of those symbols acts as a major | |
850 | * version for tracepoints. | |
851 | * | |
852 | * Older instrumented applications should still work with newer | |
853 | * liblttng-ust, but it is fine that instrumented applications compiled | |
854 | * against recent liblttng-ust headers require a recent liblttng-ust | |
855 | * runtime for those tracepoints to be taken into account. | |
856 | */ | |
4b4a1337 MJ |
857 | int tracepoint_register_lib(struct lttng_ust_tracepoint * const *tracepoints_start, |
858 | int tracepoints_count); | |
ae14f822 | 859 | int tracepoint_register_lib(struct lttng_ust_tracepoint * const *tracepoints_start, |
10544ee8 | 860 | int tracepoints_count) |
474d745f | 861 | { |
b467f7a7 | 862 | struct tracepoint_lib *pl, *iter; |
474d745f | 863 | |
25afb7ac | 864 | lttng_ust_tp_init(); |
edaa1431 | 865 | |
1dba3e6c | 866 | pl = (struct tracepoint_lib *) zmalloc(sizeof(struct tracepoint_lib)); |
d6297168 MD |
867 | if (!pl) { |
868 | PERROR("Unable to register tracepoint lib"); | |
869 | return -1; | |
870 | } | |
474d745f PMF |
871 | pl->tracepoints_start = tracepoints_start; |
872 | pl->tracepoints_count = tracepoints_count; | |
3469bbbe | 873 | CDS_INIT_LIST_HEAD(&pl->callsites); |
474d745f | 874 | |
8792fbae | 875 | pthread_mutex_lock(&tracepoint_mutex); |
b467f7a7 MD |
876 | /* |
877 | * We sort the libs by struct lib pointer address. | |
878 | */ | |
879 | cds_list_for_each_entry_reverse(iter, &libs, list) { | |
880 | BUG_ON(iter == pl); /* Should never be in the list twice */ | |
881 | if (iter < pl) { | |
882 | /* We belong to the location right after iter. */ | |
883 | cds_list_add(&pl->list, &iter->list); | |
884 | goto lib_added; | |
885 | } | |
886 | } | |
887 | /* We should be added at the head of the list */ | |
0222e121 | 888 | cds_list_add(&pl->list, &libs); |
b467f7a7 | 889 | lib_added: |
474d745f | 890 | new_tracepoints(tracepoints_start, tracepoints_start + tracepoints_count); |
3469bbbe | 891 | lib_register_callsites(pl); |
5da10905 | 892 | lib_update_tracepoints(pl); |
8792fbae | 893 | pthread_mutex_unlock(&tracepoint_mutex); |
474d745f | 894 | |
1fcf7ad7 MD |
895 | DBG("just registered a tracepoints section from %p and having %d tracepoints", |
896 | tracepoints_start, tracepoints_count); | |
2b6f4374 | 897 | if (ust_err_debug_enabled()) { |
05780d81 MD |
898 | int i; |
899 | ||
900 | for (i = 0; i < tracepoints_count; i++) { | |
901 | DBG("registered tracepoint: %s", tracepoints_start[i]->name); | |
902 | } | |
903 | } | |
9dec086e | 904 | |
474d745f PMF |
905 | return 0; |
906 | } | |
907 | ||
4b4a1337 | 908 | int tracepoint_unregister_lib(struct lttng_ust_tracepoint * const *tracepoints_start); |
ae14f822 | 909 | int tracepoint_unregister_lib(struct lttng_ust_tracepoint * const *tracepoints_start) |
474d745f | 910 | { |
24b6668c PMF |
911 | struct tracepoint_lib *lib; |
912 | ||
8792fbae | 913 | pthread_mutex_lock(&tracepoint_mutex); |
0222e121 | 914 | cds_list_for_each_entry(lib, &libs, list) { |
3469bbbe MD |
915 | if (lib->tracepoints_start != tracepoints_start) |
916 | continue; | |
1622ba22 | 917 | |
3469bbbe MD |
918 | cds_list_del(&lib->list); |
919 | /* | |
8a7ad54b IJ |
920 | * Unregistering a callsite also decreases the |
921 | * callsite reference count of the corresponding | |
922 | * tracepoint, and disables the tracepoint if | |
923 | * the reference count drops to zero. | |
3469bbbe | 924 | */ |
3469bbbe MD |
925 | lib_unregister_callsites(lib); |
926 | DBG("just unregistered a tracepoints section from %p", | |
927 | lib->tracepoints_start); | |
928 | free(lib); | |
929 | break; | |
24b6668c | 930 | } |
8792fbae | 931 | pthread_mutex_unlock(&tracepoint_mutex); |
474d745f PMF |
932 | return 0; |
933 | } | |
b27f8e75 | 934 | |
5517d34d MD |
935 | /* |
936 | * Report in debug message whether the compiler correctly supports weak | |
937 | * hidden symbols. This test checks that the address associated with two | |
938 | * weak symbols with hidden visibility is the same when declared within | |
939 | * two compile units part of the same module. | |
940 | */ | |
941 | static void check_weak_hidden(void) | |
942 | { | |
b0e63efd MD |
943 | DBG("Your compiler treats weak symbols with hidden visibility for integer objects as %s between compile units part of the same module.", |
944 | &__tracepoint_test_symbol1 == lttng_ust_tp_check_weak_hidden1() ? | |
945 | "SAME address" : | |
946 | "DIFFERENT addresses"); | |
947 | DBG("Your compiler treats weak symbols with hidden visibility for pointer objects as %s between compile units part of the same module.", | |
948 | &__tracepoint_test_symbol2 == lttng_ust_tp_check_weak_hidden2() ? | |
949 | "SAME address" : | |
950 | "DIFFERENT addresses"); | |
951 | DBG("Your compiler treats weak symbols with hidden visibility for 24-byte structure objects as %s between compile units part of the same module.", | |
952 | &__tracepoint_test_symbol3 == lttng_ust_tp_check_weak_hidden3() ? | |
953 | "SAME address" : | |
954 | "DIFFERENT addresses"); | |
5517d34d MD |
955 | } |
956 | ||
25afb7ac | 957 | void lttng_ust_tp_init(void) |
b27f8e75 | 958 | { |
edaa1431 MD |
959 | if (uatomic_xchg(&initialized, 1) == 1) |
960 | return; | |
2b6f4374 | 961 | ust_err_init(); |
5517d34d | 962 | check_weak_hidden(); |
b27f8e75 MD |
963 | } |
964 | ||
25afb7ac | 965 | void lttng_ust_tp_exit(void) |
b27f8e75 | 966 | { |
17dfb34b | 967 | initialized = 0; |
b27f8e75 | 968 | } |
40b2b5a4 MD |
969 | |
970 | /* | |
971 | * Create the wrapper symbols. | |
972 | */ | |
10544ee8 MD |
973 | #undef tp_rcu_read_lock |
974 | #undef tp_rcu_read_unlock | |
975 | #undef tp_rcu_dereference | |
40b2b5a4 | 976 | |
4b4a1337 | 977 | void tp_rcu_read_lock(void); |
10544ee8 | 978 | void tp_rcu_read_lock(void) |
40b2b5a4 | 979 | { |
10544ee8 | 980 | lttng_ust_urcu_read_lock(); |
40b2b5a4 MD |
981 | } |
982 | ||
4b4a1337 | 983 | void tp_rcu_read_unlock(void); |
10544ee8 | 984 | void tp_rcu_read_unlock(void) |
40b2b5a4 | 985 | { |
10544ee8 | 986 | lttng_ust_urcu_read_unlock(); |
40b2b5a4 MD |
987 | } |
988 | ||
4b4a1337 | 989 | void *tp_rcu_dereference_sym(void *p); |
10544ee8 | 990 | void *tp_rcu_dereference_sym(void *p) |
40b2b5a4 | 991 | { |
10544ee8 | 992 | return lttng_ust_rcu_dereference(p); |
40b2b5a4 | 993 | } |
0fd0de10 FD |
994 | |
995 | /* | |
996 | * Programs that have threads that survive after they exit, and therefore call | |
997 | * library destructors, should disable the tracepoint destructors by calling | |
998 | * tp_disable_destructors(). This will leak the tracepoint | |
999 | * instrumentation library shared object, leaving its teardown to the operating | |
1000 | * system process teardown. | |
1001 | * | |
1002 | * To access and/or modify this value, users need to use a combination of | |
1003 | * dlopen(3) and dlsym(3) to get an handle on the | |
1004 | * tp_disable_destructors and tp_get_destructors_state symbols below. | |
1005 | */ | |
4b4a1337 | 1006 | void tp_disable_destructors(void); |
0fd0de10 FD |
1007 | void tp_disable_destructors(void) |
1008 | { | |
1009 | uatomic_set(&tracepoint_destructors_state, 0); | |
1010 | } | |
1011 | ||
1012 | /* | |
1013 | * Returns 1 if the destructors are enabled and should be executed. | |
1014 | * Returns 0 if the destructors are disabled. | |
1015 | */ | |
4b4a1337 | 1016 | int tp_get_destructors_state(void); |
0fd0de10 FD |
1017 | int tp_get_destructors_state(void) |
1018 | { | |
1019 | return uatomic_read(&tracepoint_destructors_state); | |
1020 | } |