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 */ |
fca97dfd | 25 | #include <lttng/ust-common.h> |
44c72f10 | 26 | |
9d315d6d MJ |
27 | #include "common/logging.h" |
28 | #include "common/macros.h" | |
474d745f | 29 | |
8f51c684 MJ |
30 | #include "lib/lttng-ust-tracepoint/tracepoint.h" |
31 | #include "common/tracepoint.h" | |
e58e5ad5 | 32 | #include "common/jhash.h" |
9c4fe08d | 33 | #include "common/err-ptr.h" |
b0c4126f | 34 | |
5517d34d | 35 | /* Test compiler support for weak symbols with hidden visibility. */ |
b0e63efd MD |
36 | int __tracepoint_test_symbol1 __attribute__((weak, visibility("hidden"))); |
37 | void *__tracepoint_test_symbol2 __attribute__((weak, visibility("hidden"))); | |
38 | struct { | |
39 | char a[24]; | |
40 | } __tracepoint_test_symbol3 __attribute__((weak, visibility("hidden"))); | |
5517d34d | 41 | |
f99be407 PMF |
42 | /* Set to 1 to enable tracepoint debug output */ |
43 | static const int tracepoint_debug; | |
b27f8e75 | 44 | static int initialized; |
0fd0de10 FD |
45 | |
46 | /* | |
47 | * If tracepoint_destructors_state = 1, tracepoint destructors are | |
48 | * enabled. They are disabled otherwise. | |
49 | */ | |
50 | static int tracepoint_destructors_state = 1; | |
51 | ||
1a206094 | 52 | static void (*new_tracepoint_cb)(struct lttng_ust_tracepoint *); |
f99be407 | 53 | |
8792fbae MD |
54 | /* |
55 | * tracepoint_mutex nests inside UST mutex. | |
56 | * | |
57 | * Note about interaction with fork/clone: UST does not hold the | |
58 | * tracepoint mutex across fork/clone because it is either: | |
59 | * - nested within UST mutex, in which case holding the UST mutex across | |
60 | * fork/clone suffice, | |
61 | * - taken by a library constructor, which should never race with a | |
62 | * fork/clone if the application is expected to continue running with | |
63 | * the same memory layout (no following exec()). | |
64 | */ | |
65 | static pthread_mutex_t tracepoint_mutex = PTHREAD_MUTEX_INITIALIZER; | |
66 | ||
efa2c591 MD |
67 | /* |
68 | * libraries that contain tracepoints (struct tracepoint_lib). | |
8792fbae | 69 | * Protected by tracepoint mutex. |
efa2c591 | 70 | */ |
0222e121 | 71 | static CDS_LIST_HEAD(libs); |
474d745f | 72 | |
f99be407 | 73 | /* |
8792fbae | 74 | * The tracepoint mutex protects the library tracepoints, the hash table, and |
17dfb34b | 75 | * the library list. |
8792fbae | 76 | * All calls to the tracepoint API must be protected by the tracepoint mutex, |
17dfb34b | 77 | * excepts calls to tracepoint_register_lib and |
8792fbae | 78 | * tracepoint_unregister_lib, which take the tracepoint mutex themselves. |
f99be407 | 79 | */ |
f99be407 PMF |
80 | |
81 | /* | |
82 | * Tracepoint hash table, containing the active tracepoints. | |
8792fbae | 83 | * Protected by tracepoint mutex. |
f99be407 | 84 | */ |
814f7df1 | 85 | #define TRACEPOINT_HASH_BITS 12 |
f99be407 | 86 | #define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS) |
10c56168 | 87 | static struct cds_hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE]; |
f99be407 | 88 | |
b27f8e75 MD |
89 | static CDS_LIST_HEAD(old_probes); |
90 | static int need_update; | |
91 | ||
baa1e0bc MD |
92 | static CDS_LIST_HEAD(release_queue); |
93 | static int release_queue_need_update; | |
94 | ||
f99be407 PMF |
95 | /* |
96 | * Note about RCU : | |
97 | * It is used to to delay the free of multiple probes array until a quiescent | |
98 | * state is reached. | |
8792fbae | 99 | * Tracepoint entries modifications are protected by the tracepoint mutex. |
f99be407 PMF |
100 | */ |
101 | struct tracepoint_entry { | |
10c56168 | 102 | struct cds_hlist_node hlist; |
1a206094 | 103 | struct lttng_ust_tracepoint_probe *probes; |
f99be407 | 104 | int refcount; /* Number of times armed. 0 if disarmed. */ |
8a7ad54b | 105 | int callsite_refcount; /* how many libs use this tracepoint */ |
2c05c691 FD |
106 | char *signature; |
107 | char *name; | |
f99be407 PMF |
108 | }; |
109 | ||
110 | struct tp_probes { | |
111 | union { | |
0222e121 | 112 | struct cds_list_head list; |
ade7037b MD |
113 | /* Field below only used for call_rcu scheme */ |
114 | /* struct rcu_head head; */ | |
f99be407 | 115 | } u; |
1a206094 | 116 | struct lttng_ust_tracepoint_probe probes[0]; |
f99be407 PMF |
117 | }; |
118 | ||
3469bbbe MD |
119 | /* |
120 | * Callsite hash table, containing the tracepoint call sites. | |
121 | * Protected by tracepoint mutex. | |
122 | */ | |
123 | #define CALLSITE_HASH_BITS 12 | |
124 | #define CALLSITE_TABLE_SIZE (1 << CALLSITE_HASH_BITS) | |
125 | static struct cds_hlist_head callsite_table[CALLSITE_TABLE_SIZE]; | |
126 | ||
127 | struct callsite_entry { | |
128 | struct cds_hlist_node hlist; /* hash table node */ | |
129 | struct cds_list_head node; /* lib list of callsites node */ | |
1a206094 | 130 | struct lttng_ust_tracepoint *tp; |
2c05c691 | 131 | bool tp_entry_callsite_ref; /* Has a tp_entry took a ref on this callsite */ |
3469bbbe MD |
132 | }; |
133 | ||
81b16412 MD |
134 | lttng_ust_static_assert(LTTNG_UST_TRACEPOINT_NAME_LEN_MAX == LTTNG_UST_ABI_SYM_NAME_LEN, |
135 | "Tracepoint name max length mismatch between UST ABI and tracepoint API", | |
136 | Tracepoint_name_max_length_mismatch); | |
137 | ||
5e6df7ea | 138 | /* coverity[+alloc] */ |
efa2c591 | 139 | static void *allocate_probes(int count) |
f99be407 | 140 | { |
1a206094 SM |
141 | struct tp_probes *p = |
142 | zmalloc(count * sizeof(struct lttng_ust_tracepoint_probe) | |
143 | + sizeof(struct tp_probes)); | |
f99be407 PMF |
144 | return p == NULL ? NULL : p->probes; |
145 | } | |
146 | ||
5e6df7ea | 147 | /* coverity[+free : arg-0] */ |
efa2c591 | 148 | static void release_probes(void *old) |
f99be407 PMF |
149 | { |
150 | if (old) { | |
b728d87e | 151 | struct tp_probes *tp_probes = caa_container_of(old, |
f99be407 | 152 | struct tp_probes, probes[0]); |
b653ddc1 | 153 | lttng_ust_urcu_synchronize_rcu(); |
909bc43f | 154 | free(tp_probes); |
f99be407 PMF |
155 | } |
156 | } | |
157 | ||
158 | static void debug_print_probes(struct tracepoint_entry *entry) | |
159 | { | |
160 | int i; | |
161 | ||
9dec086e | 162 | if (!tracepoint_debug || !entry->probes) |
f99be407 PMF |
163 | return; |
164 | ||
9dec086e NC |
165 | for (i = 0; entry->probes[i].func; i++) |
166 | DBG("Probe %d : %p", i, entry->probes[i].func); | |
f99be407 PMF |
167 | } |
168 | ||
169 | static void * | |
9dec086e | 170 | tracepoint_entry_add_probe(struct tracepoint_entry *entry, |
fbdeb5ec | 171 | void (*probe)(void), void *data) |
f99be407 PMF |
172 | { |
173 | int nr_probes = 0; | |
1a206094 | 174 | struct lttng_ust_tracepoint_probe *old, *new; |
f99be407 | 175 | |
d7509147 MD |
176 | if (!probe) { |
177 | WARN_ON(1); | |
178 | return ERR_PTR(-EINVAL); | |
179 | } | |
f99be407 | 180 | debug_print_probes(entry); |
9dec086e | 181 | old = entry->probes; |
f99be407 PMF |
182 | if (old) { |
183 | /* (N -> N+1), (N != 0, 1) probes */ | |
9dec086e NC |
184 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) |
185 | if (old[nr_probes].func == probe && | |
186 | old[nr_probes].data == data) | |
f99be407 PMF |
187 | return ERR_PTR(-EEXIST); |
188 | } | |
189 | /* + 2 : one for new probe, one for NULL func */ | |
190 | new = allocate_probes(nr_probes + 2); | |
191 | if (new == NULL) | |
192 | return ERR_PTR(-ENOMEM); | |
193 | if (old) | |
1a206094 SM |
194 | memcpy(new, old, |
195 | nr_probes * sizeof(struct lttng_ust_tracepoint_probe)); | |
9dec086e NC |
196 | new[nr_probes].func = probe; |
197 | new[nr_probes].data = data; | |
198 | new[nr_probes + 1].func = NULL; | |
f99be407 | 199 | entry->refcount = nr_probes + 1; |
9dec086e | 200 | entry->probes = new; |
f99be407 PMF |
201 | debug_print_probes(entry); |
202 | return old; | |
203 | } | |
204 | ||
205 | static void * | |
fbdeb5ec MD |
206 | tracepoint_entry_remove_probe(struct tracepoint_entry *entry, |
207 | void (*probe)(void), void *data) | |
f99be407 PMF |
208 | { |
209 | int nr_probes = 0, nr_del = 0, i; | |
1a206094 | 210 | struct lttng_ust_tracepoint_probe *old, *new; |
f99be407 | 211 | |
9dec086e | 212 | old = entry->probes; |
f99be407 PMF |
213 | |
214 | if (!old) | |
215 | return ERR_PTR(-ENOENT); | |
216 | ||
217 | debug_print_probes(entry); | |
218 | /* (N -> M), (N > 1, M >= 0) probes */ | |
956c6fab MD |
219 | if (probe) { |
220 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) { | |
221 | if (old[nr_probes].func == probe && | |
222 | old[nr_probes].data == data) | |
223 | nr_del++; | |
224 | } | |
f99be407 PMF |
225 | } |
226 | ||
227 | if (nr_probes - nr_del == 0) { | |
228 | /* N -> 0, (N > 1) */ | |
9dec086e | 229 | entry->probes = NULL; |
f99be407 PMF |
230 | entry->refcount = 0; |
231 | debug_print_probes(entry); | |
232 | return old; | |
233 | } else { | |
234 | int j = 0; | |
235 | /* N -> M, (N > 1, M > 0) */ | |
236 | /* + 1 for NULL */ | |
237 | new = allocate_probes(nr_probes - nr_del + 1); | |
238 | if (new == NULL) | |
239 | return ERR_PTR(-ENOMEM); | |
9dec086e | 240 | for (i = 0; old[i].func; i++) |
956c6fab | 241 | if (old[i].func != probe || old[i].data != data) |
f99be407 | 242 | new[j++] = old[i]; |
9dec086e | 243 | new[nr_probes - nr_del].func = NULL; |
f99be407 | 244 | entry->refcount = nr_probes - nr_del; |
9dec086e | 245 | entry->probes = new; |
f99be407 PMF |
246 | } |
247 | debug_print_probes(entry); | |
248 | return old; | |
249 | } | |
250 | ||
251 | /* | |
252 | * Get tracepoint if the tracepoint is present in the tracepoint hash table. | |
8792fbae | 253 | * Must be called with tracepoint mutex held. |
f99be407 PMF |
254 | * Returns NULL if not present. |
255 | */ | |
256 | static struct tracepoint_entry *get_tracepoint(const char *name) | |
257 | { | |
10c56168 DG |
258 | struct cds_hlist_head *head; |
259 | struct cds_hlist_node *node; | |
f99be407 | 260 | struct tracepoint_entry *e; |
ff412fb5 MD |
261 | size_t name_len = strlen(name); |
262 | uint32_t hash; | |
f99be407 | 263 | |
fd17d7ce MD |
264 | if (name_len > LTTNG_UST_ABI_SYM_NAME_LEN - 1) { |
265 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_ABI_SYM_NAME_LEN - 1); | |
266 | name_len = LTTNG_UST_ABI_SYM_NAME_LEN - 1; | |
ff412fb5 MD |
267 | } |
268 | hash = jhash(name, name_len, 0); | |
f99be407 | 269 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
10c56168 | 270 | cds_hlist_for_each_entry(e, node, head, hlist) { |
fd17d7ce | 271 | if (!strncmp(name, e->name, LTTNG_UST_ABI_SYM_NAME_LEN - 1)) |
f99be407 PMF |
272 | return e; |
273 | } | |
274 | return NULL; | |
275 | } | |
276 | ||
277 | /* | |
278 | * Add the tracepoint to the tracepoint hash table. Must be called with | |
8792fbae | 279 | * tracepoint mutex held. |
f99be407 | 280 | */ |
67e5f391 MD |
281 | static struct tracepoint_entry *add_tracepoint(const char *name, |
282 | const char *signature) | |
f99be407 | 283 | { |
10c56168 DG |
284 | struct cds_hlist_head *head; |
285 | struct cds_hlist_node *node; | |
f99be407 | 286 | struct tracepoint_entry *e; |
ff412fb5 | 287 | size_t name_len = strlen(name); |
2c05c691 FD |
288 | size_t sig_len = strlen(signature); |
289 | size_t sig_off, name_off; | |
ff412fb5 | 290 | uint32_t hash; |
f99be407 | 291 | |
fd17d7ce MD |
292 | if (name_len > LTTNG_UST_ABI_SYM_NAME_LEN - 1) { |
293 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_ABI_SYM_NAME_LEN - 1); | |
294 | name_len = LTTNG_UST_ABI_SYM_NAME_LEN - 1; | |
ff412fb5 MD |
295 | } |
296 | hash = jhash(name, name_len, 0); | |
f99be407 | 297 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
10c56168 | 298 | cds_hlist_for_each_entry(e, node, head, hlist) { |
fd17d7ce | 299 | if (!strncmp(name, e->name, LTTNG_UST_ABI_SYM_NAME_LEN - 1)) { |
c1f20530 | 300 | DBG("tracepoint %s busy", name); |
f99be407 PMF |
301 | return ERR_PTR(-EEXIST); /* Already there */ |
302 | } | |
303 | } | |
2c05c691 | 304 | |
f99be407 | 305 | /* |
2c05c691 FD |
306 | * Using zmalloc here to allocate a variable length elements: name and |
307 | * signature. Could cause some memory fragmentation if overused. | |
f99be407 | 308 | */ |
2c05c691 FD |
309 | name_off = sizeof(struct tracepoint_entry); |
310 | sig_off = name_off + name_len + 1; | |
311 | ||
312 | e = zmalloc(sizeof(struct tracepoint_entry) + name_len + 1 + sig_len + 1); | |
f99be407 PMF |
313 | if (!e) |
314 | return ERR_PTR(-ENOMEM); | |
2c05c691 FD |
315 | e->name = (char *) e + name_off; |
316 | memcpy(e->name, name, name_len + 1); | |
ff412fb5 | 317 | e->name[name_len] = '\0'; |
2c05c691 FD |
318 | |
319 | e->signature = (char *) e + sig_off; | |
320 | memcpy(e->signature, signature, sig_len + 1); | |
321 | e->signature[sig_len] = '\0'; | |
322 | ||
9dec086e | 323 | e->probes = NULL; |
f99be407 | 324 | e->refcount = 0; |
8a7ad54b | 325 | e->callsite_refcount = 0; |
2c05c691 | 326 | |
10c56168 | 327 | cds_hlist_add_head(&e->hlist, head); |
f99be407 PMF |
328 | return e; |
329 | } | |
330 | ||
331 | /* | |
332 | * Remove the tracepoint from the tracepoint hash table. Must be called with | |
8792fbae | 333 | * tracepoint mutex held. |
f99be407 | 334 | */ |
efa2c591 | 335 | static void remove_tracepoint(struct tracepoint_entry *e) |
f99be407 | 336 | { |
10c56168 | 337 | cds_hlist_del(&e->hlist); |
909bc43f | 338 | free(e); |
f99be407 PMF |
339 | } |
340 | ||
341 | /* | |
342 | * Sets the probe callback corresponding to one tracepoint. | |
343 | */ | |
344 | static void set_tracepoint(struct tracepoint_entry **entry, | |
1a206094 | 345 | struct lttng_ust_tracepoint *elem, int active) |
f99be407 | 346 | { |
fd17d7ce | 347 | WARN_ON(strncmp((*entry)->name, elem->name, LTTNG_UST_ABI_SYM_NAME_LEN - 1) != 0); |
67e5f391 MD |
348 | /* |
349 | * Check that signatures match before connecting a probe to a | |
350 | * tracepoint. Warn the user if they don't. | |
351 | */ | |
352 | if (strcmp(elem->signature, (*entry)->signature) != 0) { | |
353 | static int warned = 0; | |
354 | ||
355 | /* Only print once, don't flood console. */ | |
356 | if (!warned) { | |
357 | WARN("Tracepoint signature mismatch, not enabling one or more tracepoints. Ensure that the tracepoint probes prototypes match the application."); | |
358 | WARN("Tracepoint \"%s\" signatures: call: \"%s\" vs probe: \"%s\".", | |
359 | elem->name, elem->signature, (*entry)->signature); | |
360 | warned = 1; | |
361 | } | |
362 | /* Don't accept connecting non-matching signatures. */ | |
363 | return; | |
364 | } | |
f99be407 PMF |
365 | |
366 | /* | |
0222e121 | 367 | * rcu_assign_pointer has a cmm_smp_wmb() which makes sure that the new |
f99be407 PMF |
368 | * probe callbacks array is consistent before setting a pointer to it. |
369 | * This array is referenced by __DO_TRACE from | |
0222e121 | 370 | * include/linux/tracepoints.h. A matching cmm_smp_read_barrier_depends() |
f99be407 PMF |
371 | * is used. |
372 | */ | |
10544ee8 | 373 | lttng_ust_rcu_assign_pointer(elem->probes, (*entry)->probes); |
c082d14b | 374 | CMM_STORE_SHARED(elem->state, active); |
f99be407 PMF |
375 | } |
376 | ||
377 | /* | |
378 | * Disable a tracepoint and its probe callback. | |
379 | * Note: only waiting an RCU period after setting elem->call to the empty | |
380 | * function insures that the original callback is not used anymore. This insured | |
381 | * by preempt_disable around the call site. | |
382 | */ | |
1a206094 | 383 | static void disable_tracepoint(struct lttng_ust_tracepoint *elem) |
f99be407 | 384 | { |
c082d14b | 385 | CMM_STORE_SHARED(elem->state, 0); |
10544ee8 | 386 | lttng_ust_rcu_assign_pointer(elem->probes, NULL); |
f99be407 PMF |
387 | } |
388 | ||
33f8ed87 MD |
389 | /* |
390 | * Add the callsite to the callsite hash table. Must be called with | |
391 | * tracepoint mutex held. | |
392 | */ | |
1a206094 | 393 | static void add_callsite(struct tracepoint_lib * lib, struct lttng_ust_tracepoint *tp) |
33f8ed87 MD |
394 | { |
395 | struct cds_hlist_head *head; | |
396 | struct callsite_entry *e; | |
397 | const char *name = tp->name; | |
398 | size_t name_len = strlen(name); | |
399 | uint32_t hash; | |
8a7ad54b | 400 | struct tracepoint_entry *tp_entry; |
33f8ed87 | 401 | |
fd17d7ce MD |
402 | if (name_len > LTTNG_UST_ABI_SYM_NAME_LEN - 1) { |
403 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_ABI_SYM_NAME_LEN - 1); | |
404 | name_len = LTTNG_UST_ABI_SYM_NAME_LEN - 1; | |
33f8ed87 MD |
405 | } |
406 | hash = jhash(name, name_len, 0); | |
407 | head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)]; | |
408 | e = zmalloc(sizeof(struct callsite_entry)); | |
d6297168 MD |
409 | if (!e) { |
410 | PERROR("Unable to add callsite for tracepoint \"%s\"", name); | |
411 | return; | |
412 | } | |
33f8ed87 MD |
413 | cds_hlist_add_head(&e->hlist, head); |
414 | e->tp = tp; | |
415 | cds_list_add(&e->node, &lib->callsites); | |
8a7ad54b IJ |
416 | |
417 | tp_entry = get_tracepoint(name); | |
418 | if (!tp_entry) | |
419 | return; | |
420 | tp_entry->callsite_refcount++; | |
2c05c691 | 421 | e->tp_entry_callsite_ref = true; |
33f8ed87 MD |
422 | } |
423 | ||
424 | /* | |
425 | * Remove the callsite from the callsite hash table and from lib | |
426 | * callsite list. Must be called with tracepoint mutex held. | |
427 | */ | |
428 | static void remove_callsite(struct callsite_entry *e) | |
429 | { | |
8a7ad54b IJ |
430 | struct tracepoint_entry *tp_entry; |
431 | ||
432 | tp_entry = get_tracepoint(e->tp->name); | |
433 | if (tp_entry) { | |
2c05c691 FD |
434 | if (e->tp_entry_callsite_ref) |
435 | tp_entry->callsite_refcount--; | |
8a7ad54b IJ |
436 | if (tp_entry->callsite_refcount == 0) |
437 | disable_tracepoint(e->tp); | |
438 | } | |
33f8ed87 MD |
439 | cds_hlist_del(&e->hlist); |
440 | cds_list_del(&e->node); | |
441 | free(e); | |
442 | } | |
443 | ||
3469bbbe MD |
444 | /* |
445 | * Enable/disable all callsites based on the state of a specific | |
446 | * tracepoint entry. | |
447 | * Must be called with tracepoint mutex held. | |
448 | */ | |
449 | static void tracepoint_sync_callsites(const char *name) | |
450 | { | |
451 | struct cds_hlist_head *head; | |
452 | struct cds_hlist_node *node; | |
453 | struct callsite_entry *e; | |
454 | size_t name_len = strlen(name); | |
455 | uint32_t hash; | |
456 | struct tracepoint_entry *tp_entry; | |
457 | ||
458 | tp_entry = get_tracepoint(name); | |
fd17d7ce MD |
459 | if (name_len > LTTNG_UST_ABI_SYM_NAME_LEN - 1) { |
460 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_ABI_SYM_NAME_LEN - 1); | |
461 | name_len = LTTNG_UST_ABI_SYM_NAME_LEN - 1; | |
3469bbbe MD |
462 | } |
463 | hash = jhash(name, name_len, 0); | |
464 | head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)]; | |
465 | cds_hlist_for_each_entry(e, node, head, hlist) { | |
1a206094 | 466 | struct lttng_ust_tracepoint *tp = e->tp; |
3469bbbe | 467 | |
fd17d7ce | 468 | if (strncmp(name, tp->name, LTTNG_UST_ABI_SYM_NAME_LEN - 1)) |
3469bbbe MD |
469 | continue; |
470 | if (tp_entry) { | |
2c05c691 FD |
471 | if (!e->tp_entry_callsite_ref) { |
472 | tp_entry->callsite_refcount++; | |
473 | e->tp_entry_callsite_ref = true; | |
474 | } | |
3469bbbe MD |
475 | set_tracepoint(&tp_entry, tp, |
476 | !!tp_entry->refcount); | |
477 | } else { | |
478 | disable_tracepoint(tp); | |
2c05c691 | 479 | e->tp_entry_callsite_ref = false; |
3469bbbe MD |
480 | } |
481 | } | |
482 | } | |
483 | ||
f99be407 PMF |
484 | /** |
485 | * tracepoint_update_probe_range - Update a probe range | |
486 | * @begin: beginning of the range | |
487 | * @end: end of the range | |
488 | * | |
489 | * Updates the probe callback corresponding to a range of tracepoints. | |
490 | */ | |
b27f8e75 | 491 | static |
1a206094 SM |
492 | void tracepoint_update_probe_range(struct lttng_ust_tracepoint * const *begin, |
493 | struct lttng_ust_tracepoint * const *end) | |
f99be407 | 494 | { |
1a206094 | 495 | struct lttng_ust_tracepoint * const *iter; |
f99be407 PMF |
496 | struct tracepoint_entry *mark_entry; |
497 | ||
f99be407 | 498 | for (iter = begin; iter < end; iter++) { |
f08ebbe2 MD |
499 | if (!*iter) |
500 | continue; /* skip dummy */ | |
f218ff28 MD |
501 | if (!(*iter)->name) { |
502 | disable_tracepoint(*iter); | |
9dec086e NC |
503 | continue; |
504 | } | |
f218ff28 | 505 | mark_entry = get_tracepoint((*iter)->name); |
f99be407 | 506 | if (mark_entry) { |
f218ff28 | 507 | set_tracepoint(&mark_entry, *iter, |
f99be407 PMF |
508 | !!mark_entry->refcount); |
509 | } else { | |
f218ff28 | 510 | disable_tracepoint(*iter); |
f99be407 PMF |
511 | } |
512 | } | |
f99be407 PMF |
513 | } |
514 | ||
5da10905 | 515 | static void lib_update_tracepoints(struct tracepoint_lib *lib) |
772030fe | 516 | { |
5da10905 MD |
517 | tracepoint_update_probe_range(lib->tracepoints_start, |
518 | lib->tracepoints_start + lib->tracepoints_count); | |
772030fe PMF |
519 | } |
520 | ||
3469bbbe MD |
521 | static void lib_register_callsites(struct tracepoint_lib *lib) |
522 | { | |
1a206094 SM |
523 | struct lttng_ust_tracepoint * const *begin; |
524 | struct lttng_ust_tracepoint * const *end; | |
525 | struct lttng_ust_tracepoint * const *iter; | |
3469bbbe MD |
526 | |
527 | begin = lib->tracepoints_start; | |
528 | end = lib->tracepoints_start + lib->tracepoints_count; | |
529 | ||
530 | for (iter = begin; iter < end; iter++) { | |
531 | if (!*iter) | |
532 | continue; /* skip dummy */ | |
533 | if (!(*iter)->name) { | |
534 | continue; | |
535 | } | |
60d87029 | 536 | add_callsite(lib, *iter); |
3469bbbe MD |
537 | } |
538 | } | |
539 | ||
540 | static void lib_unregister_callsites(struct tracepoint_lib *lib) | |
541 | { | |
542 | struct callsite_entry *callsite, *tmp; | |
543 | ||
544 | cds_list_for_each_entry_safe(callsite, tmp, &lib->callsites, node) | |
545 | remove_callsite(callsite); | |
546 | } | |
547 | ||
f99be407 PMF |
548 | /* |
549 | * Update probes, removing the faulty probes. | |
550 | */ | |
551 | static void tracepoint_update_probes(void) | |
552 | { | |
5da10905 MD |
553 | struct tracepoint_lib *lib; |
554 | ||
b27f8e75 | 555 | /* tracepoints registered from libraries and executable. */ |
5da10905 MD |
556 | cds_list_for_each_entry(lib, &libs, list) |
557 | lib_update_tracepoints(lib); | |
f99be407 PMF |
558 | } |
559 | ||
1a206094 | 560 | static struct lttng_ust_tracepoint_probe * |
fbdeb5ec | 561 | tracepoint_add_probe(const char *name, void (*probe)(void), void *data, |
67e5f391 | 562 | const char *signature) |
f99be407 PMF |
563 | { |
564 | struct tracepoint_entry *entry; | |
1a206094 | 565 | struct lttng_ust_tracepoint_probe *old; |
f99be407 PMF |
566 | |
567 | entry = get_tracepoint(name); | |
2c05c691 FD |
568 | if (entry) { |
569 | if (strcmp(entry->signature, signature) != 0) { | |
570 | ERR("Tracepoint and probe signature do not match."); | |
571 | return ERR_PTR(-EINVAL); | |
572 | } | |
573 | } else { | |
67e5f391 | 574 | entry = add_tracepoint(name, signature); |
f99be407 | 575 | if (IS_ERR(entry)) |
1a206094 | 576 | return (struct lttng_ust_tracepoint_probe *)entry; |
f99be407 | 577 | } |
9dec086e | 578 | old = tracepoint_entry_add_probe(entry, probe, data); |
f99be407 PMF |
579 | if (IS_ERR(old) && !entry->refcount) |
580 | remove_tracepoint(entry); | |
581 | return old; | |
582 | } | |
583 | ||
baa1e0bc MD |
584 | static void tracepoint_release_queue_add_old_probes(void *old) |
585 | { | |
586 | release_queue_need_update = 1; | |
587 | if (old) { | |
588 | struct tp_probes *tp_probes = caa_container_of(old, | |
589 | struct tp_probes, probes[0]); | |
590 | cds_list_add(&tp_probes->u.list, &release_queue); | |
591 | } | |
592 | } | |
593 | ||
f99be407 | 594 | /** |
81614639 | 595 | * __tracepoint_probe_register - Connect a probe to a tracepoint |
f99be407 PMF |
596 | * @name: tracepoint name |
597 | * @probe: probe handler | |
598 | * | |
599 | * Returns 0 if ok, error value on error. | |
600 | * The probe address must at least be aligned on the architecture pointer size. | |
8792fbae | 601 | * Called with the tracepoint mutex held. |
f99be407 | 602 | */ |
fbdeb5ec MD |
603 | int __tracepoint_probe_register(const char *name, void (*probe)(void), |
604 | void *data, const char *signature) | |
f99be407 PMF |
605 | { |
606 | void *old; | |
8792fbae | 607 | int ret = 0; |
f99be407 | 608 | |
05780d81 MD |
609 | DBG("Registering probe to tracepoint %s", name); |
610 | ||
8792fbae | 611 | pthread_mutex_lock(&tracepoint_mutex); |
67e5f391 | 612 | old = tracepoint_add_probe(name, probe, data, signature); |
8792fbae MD |
613 | if (IS_ERR(old)) { |
614 | ret = PTR_ERR(old); | |
615 | goto end; | |
616 | } | |
f99be407 | 617 | |
3469bbbe | 618 | tracepoint_sync_callsites(name); |
f99be407 | 619 | release_probes(old); |
8792fbae MD |
620 | end: |
621 | pthread_mutex_unlock(&tracepoint_mutex); | |
622 | return ret; | |
f99be407 | 623 | } |
f99be407 | 624 | |
baa1e0bc MD |
625 | /* |
626 | * Caller needs to invoke __tracepoint_probe_release_queue() after | |
d10a2205 | 627 | * calling lttng_ust_tp_probe_register_queue_release() one or multiple |
baa1e0bc MD |
628 | * times to ensure it does not leak memory. |
629 | */ | |
d10a2205 | 630 | int lttng_ust_tp_probe_register_queue_release(const char *name, |
baa1e0bc MD |
631 | void (*probe)(void), void *data, const char *signature) |
632 | { | |
633 | void *old; | |
634 | int ret = 0; | |
635 | ||
636 | DBG("Registering probe to tracepoint %s. Queuing release.", name); | |
637 | ||
638 | pthread_mutex_lock(&tracepoint_mutex); | |
639 | old = tracepoint_add_probe(name, probe, data, signature); | |
640 | if (IS_ERR(old)) { | |
641 | ret = PTR_ERR(old); | |
642 | goto end; | |
643 | } | |
644 | ||
645 | tracepoint_sync_callsites(name); | |
646 | tracepoint_release_queue_add_old_probes(old); | |
647 | end: | |
648 | pthread_mutex_unlock(&tracepoint_mutex); | |
649 | return ret; | |
650 | } | |
651 | ||
fbdeb5ec MD |
652 | static void *tracepoint_remove_probe(const char *name, void (*probe)(void), |
653 | void *data) | |
f99be407 PMF |
654 | { |
655 | struct tracepoint_entry *entry; | |
656 | void *old; | |
657 | ||
658 | entry = get_tracepoint(name); | |
659 | if (!entry) | |
660 | return ERR_PTR(-ENOENT); | |
9dec086e | 661 | old = tracepoint_entry_remove_probe(entry, probe, data); |
f99be407 PMF |
662 | if (IS_ERR(old)) |
663 | return old; | |
664 | if (!entry->refcount) | |
665 | remove_tracepoint(entry); | |
666 | return old; | |
667 | } | |
668 | ||
669 | /** | |
670 | * tracepoint_probe_unregister - Disconnect a probe from a tracepoint | |
671 | * @name: tracepoint name | |
672 | * @probe: probe function pointer | |
9dec086e | 673 | * @probe: probe data pointer |
f99be407 | 674 | */ |
fbdeb5ec MD |
675 | int __tracepoint_probe_unregister(const char *name, void (*probe)(void), |
676 | void *data) | |
f99be407 PMF |
677 | { |
678 | void *old; | |
8792fbae | 679 | int ret = 0; |
f99be407 | 680 | |
05780d81 MD |
681 | DBG("Un-registering probe from tracepoint %s", name); |
682 | ||
8792fbae | 683 | pthread_mutex_lock(&tracepoint_mutex); |
9dec086e | 684 | old = tracepoint_remove_probe(name, probe, data); |
8792fbae MD |
685 | if (IS_ERR(old)) { |
686 | ret = PTR_ERR(old); | |
687 | goto end; | |
688 | } | |
3469bbbe | 689 | tracepoint_sync_callsites(name); |
f99be407 | 690 | release_probes(old); |
8792fbae MD |
691 | end: |
692 | pthread_mutex_unlock(&tracepoint_mutex); | |
693 | return ret; | |
f99be407 | 694 | } |
f99be407 | 695 | |
baa1e0bc MD |
696 | /* |
697 | * Caller needs to invoke __tracepoint_probe_release_queue() after | |
d10a2205 | 698 | * calling lttng_ust_tp_probe_unregister_queue_release() one or multiple |
baa1e0bc MD |
699 | * times to ensure it does not leak memory. |
700 | */ | |
d10a2205 | 701 | int lttng_ust_tp_probe_unregister_queue_release(const char *name, |
baa1e0bc MD |
702 | void (*probe)(void), void *data) |
703 | { | |
704 | void *old; | |
705 | int ret = 0; | |
706 | ||
707 | DBG("Un-registering probe from tracepoint %s. Queuing release.", name); | |
708 | ||
709 | pthread_mutex_lock(&tracepoint_mutex); | |
710 | old = tracepoint_remove_probe(name, probe, data); | |
711 | if (IS_ERR(old)) { | |
712 | ret = PTR_ERR(old); | |
713 | goto end; | |
714 | } | |
715 | tracepoint_sync_callsites(name); | |
716 | tracepoint_release_queue_add_old_probes(old); | |
717 | end: | |
718 | pthread_mutex_unlock(&tracepoint_mutex); | |
719 | return ret; | |
720 | } | |
721 | ||
d10a2205 | 722 | void lttng_ust_tp_probe_prune_release_queue(void) |
baa1e0bc MD |
723 | { |
724 | CDS_LIST_HEAD(release_probes); | |
725 | struct tp_probes *pos, *next; | |
726 | ||
727 | DBG("Release queue of unregistered tracepoint probes."); | |
728 | ||
729 | pthread_mutex_lock(&tracepoint_mutex); | |
730 | if (!release_queue_need_update) | |
731 | goto end; | |
732 | if (!cds_list_empty(&release_queue)) | |
733 | cds_list_replace_init(&release_queue, &release_probes); | |
734 | release_queue_need_update = 0; | |
735 | ||
736 | /* Wait for grace period between all sync_callsites and free. */ | |
b653ddc1 | 737 | lttng_ust_urcu_synchronize_rcu(); |
baa1e0bc MD |
738 | |
739 | cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) { | |
740 | cds_list_del(&pos->u.list); | |
741 | free(pos); | |
742 | } | |
743 | end: | |
744 | pthread_mutex_unlock(&tracepoint_mutex); | |
745 | } | |
746 | ||
f99be407 PMF |
747 | static void tracepoint_add_old_probes(void *old) |
748 | { | |
749 | need_update = 1; | |
750 | if (old) { | |
b728d87e | 751 | struct tp_probes *tp_probes = caa_container_of(old, |
f99be407 | 752 | struct tp_probes, probes[0]); |
0222e121 | 753 | cds_list_add(&tp_probes->u.list, &old_probes); |
f99be407 PMF |
754 | } |
755 | } | |
756 | ||
757 | /** | |
758 | * tracepoint_probe_register_noupdate - register a probe but not connect | |
759 | * @name: tracepoint name | |
760 | * @probe: probe handler | |
761 | * | |
762 | * caller must call tracepoint_probe_update_all() | |
763 | */ | |
fbdeb5ec | 764 | int tracepoint_probe_register_noupdate(const char *name, void (*probe)(void), |
67e5f391 | 765 | void *data, const char *signature) |
f99be407 PMF |
766 | { |
767 | void *old; | |
8792fbae | 768 | int ret = 0; |
f99be407 | 769 | |
8792fbae | 770 | pthread_mutex_lock(&tracepoint_mutex); |
67e5f391 | 771 | old = tracepoint_add_probe(name, probe, data, signature); |
f99be407 | 772 | if (IS_ERR(old)) { |
8792fbae MD |
773 | ret = PTR_ERR(old); |
774 | goto end; | |
f99be407 PMF |
775 | } |
776 | tracepoint_add_old_probes(old); | |
8792fbae MD |
777 | end: |
778 | pthread_mutex_unlock(&tracepoint_mutex); | |
779 | return ret; | |
f99be407 | 780 | } |
f99be407 PMF |
781 | |
782 | /** | |
783 | * tracepoint_probe_unregister_noupdate - remove a probe but not disconnect | |
784 | * @name: tracepoint name | |
785 | * @probe: probe function pointer | |
786 | * | |
787 | * caller must call tracepoint_probe_update_all() | |
8792fbae | 788 | * Called with the tracepoint mutex held. |
f99be407 | 789 | */ |
fbdeb5ec | 790 | int tracepoint_probe_unregister_noupdate(const char *name, void (*probe)(void), |
9dec086e | 791 | void *data) |
f99be407 PMF |
792 | { |
793 | void *old; | |
8792fbae | 794 | int ret = 0; |
f99be407 | 795 | |
05780d81 MD |
796 | DBG("Un-registering probe from tracepoint %s", name); |
797 | ||
8792fbae | 798 | pthread_mutex_lock(&tracepoint_mutex); |
9dec086e | 799 | old = tracepoint_remove_probe(name, probe, data); |
f99be407 | 800 | if (IS_ERR(old)) { |
8792fbae MD |
801 | ret = PTR_ERR(old); |
802 | goto end; | |
f99be407 PMF |
803 | } |
804 | tracepoint_add_old_probes(old); | |
8792fbae MD |
805 | end: |
806 | pthread_mutex_unlock(&tracepoint_mutex); | |
807 | return ret; | |
f99be407 | 808 | } |
f99be407 PMF |
809 | |
810 | /** | |
811 | * tracepoint_probe_update_all - update tracepoints | |
812 | */ | |
813 | void tracepoint_probe_update_all(void) | |
814 | { | |
0222e121 | 815 | CDS_LIST_HEAD(release_probes); |
f99be407 PMF |
816 | struct tp_probes *pos, *next; |
817 | ||
8792fbae | 818 | pthread_mutex_lock(&tracepoint_mutex); |
f99be407 | 819 | if (!need_update) { |
8792fbae | 820 | goto end; |
f99be407 | 821 | } |
0222e121 MD |
822 | if (!cds_list_empty(&old_probes)) |
823 | cds_list_replace_init(&old_probes, &release_probes); | |
f99be407 | 824 | need_update = 0; |
f99be407 PMF |
825 | |
826 | tracepoint_update_probes(); | |
baa1e0bc | 827 | /* Wait for grace period between update_probes and free. */ |
b653ddc1 | 828 | lttng_ust_urcu_synchronize_rcu(); |
0222e121 MD |
829 | cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) { |
830 | cds_list_del(&pos->u.list); | |
909bc43f | 831 | free(pos); |
f99be407 | 832 | } |
8792fbae MD |
833 | end: |
834 | pthread_mutex_unlock(&tracepoint_mutex); | |
f99be407 | 835 | } |
f99be407 | 836 | |
1a206094 SM |
837 | static void new_tracepoints(struct lttng_ust_tracepoint * const *start, |
838 | struct lttng_ust_tracepoint * const *end) | |
f99be407 | 839 | { |
f218ff28 | 840 | if (new_tracepoint_cb) { |
1a206094 | 841 | struct lttng_ust_tracepoint * const *t; |
f08ebbe2 | 842 | |
b27f8e75 | 843 | for (t = start; t < end; t++) { |
f08ebbe2 MD |
844 | if (*t) |
845 | new_tracepoint_cb(*t); | |
474d745f PMF |
846 | } |
847 | } | |
f99be407 | 848 | } |
f99be407 | 849 | |
10544ee8 MD |
850 | /* |
851 | * tracepoint_{un,}register_lib is meant to be looked up by instrumented | |
852 | * applications through dlsym(). If found, those can register their | |
853 | * tracepoints, else those tracepoints will not be available for | |
854 | * tracing. The number at the end of those symbols acts as a major | |
855 | * version for tracepoints. | |
856 | * | |
857 | * Older instrumented applications should still work with newer | |
858 | * liblttng-ust, but it is fine that instrumented applications compiled | |
859 | * against recent liblttng-ust headers require a recent liblttng-ust | |
860 | * runtime for those tracepoints to be taken into account. | |
861 | */ | |
4b4a1337 MJ |
862 | int tracepoint_register_lib(struct lttng_ust_tracepoint * const *tracepoints_start, |
863 | int tracepoints_count); | |
ae14f822 | 864 | int tracepoint_register_lib(struct lttng_ust_tracepoint * const *tracepoints_start, |
10544ee8 | 865 | int tracepoints_count) |
474d745f | 866 | { |
b467f7a7 | 867 | struct tracepoint_lib *pl, *iter; |
474d745f | 868 | |
25afb7ac | 869 | lttng_ust_tp_init(); |
edaa1431 | 870 | |
1dba3e6c | 871 | pl = (struct tracepoint_lib *) zmalloc(sizeof(struct tracepoint_lib)); |
d6297168 MD |
872 | if (!pl) { |
873 | PERROR("Unable to register tracepoint lib"); | |
874 | return -1; | |
875 | } | |
474d745f PMF |
876 | pl->tracepoints_start = tracepoints_start; |
877 | pl->tracepoints_count = tracepoints_count; | |
3469bbbe | 878 | CDS_INIT_LIST_HEAD(&pl->callsites); |
474d745f | 879 | |
8792fbae | 880 | pthread_mutex_lock(&tracepoint_mutex); |
b467f7a7 MD |
881 | /* |
882 | * We sort the libs by struct lib pointer address. | |
883 | */ | |
884 | cds_list_for_each_entry_reverse(iter, &libs, list) { | |
885 | BUG_ON(iter == pl); /* Should never be in the list twice */ | |
886 | if (iter < pl) { | |
887 | /* We belong to the location right after iter. */ | |
888 | cds_list_add(&pl->list, &iter->list); | |
889 | goto lib_added; | |
890 | } | |
891 | } | |
892 | /* We should be added at the head of the list */ | |
0222e121 | 893 | cds_list_add(&pl->list, &libs); |
b467f7a7 | 894 | lib_added: |
474d745f | 895 | new_tracepoints(tracepoints_start, tracepoints_start + tracepoints_count); |
3469bbbe | 896 | lib_register_callsites(pl); |
5da10905 | 897 | lib_update_tracepoints(pl); |
8792fbae | 898 | pthread_mutex_unlock(&tracepoint_mutex); |
474d745f | 899 | |
1fcf7ad7 MD |
900 | DBG("just registered a tracepoints section from %p and having %d tracepoints", |
901 | tracepoints_start, tracepoints_count); | |
c6e6343c | 902 | if (lttng_ust_logging_debug_enabled()) { |
05780d81 MD |
903 | int i; |
904 | ||
905 | for (i = 0; i < tracepoints_count; i++) { | |
906 | DBG("registered tracepoint: %s", tracepoints_start[i]->name); | |
907 | } | |
908 | } | |
9dec086e | 909 | |
474d745f PMF |
910 | return 0; |
911 | } | |
912 | ||
4b4a1337 | 913 | int tracepoint_unregister_lib(struct lttng_ust_tracepoint * const *tracepoints_start); |
ae14f822 | 914 | int tracepoint_unregister_lib(struct lttng_ust_tracepoint * const *tracepoints_start) |
474d745f | 915 | { |
24b6668c PMF |
916 | struct tracepoint_lib *lib; |
917 | ||
8792fbae | 918 | pthread_mutex_lock(&tracepoint_mutex); |
0222e121 | 919 | cds_list_for_each_entry(lib, &libs, list) { |
3469bbbe MD |
920 | if (lib->tracepoints_start != tracepoints_start) |
921 | continue; | |
1622ba22 | 922 | |
3469bbbe MD |
923 | cds_list_del(&lib->list); |
924 | /* | |
8a7ad54b IJ |
925 | * Unregistering a callsite also decreases the |
926 | * callsite reference count of the corresponding | |
927 | * tracepoint, and disables the tracepoint if | |
928 | * the reference count drops to zero. | |
3469bbbe | 929 | */ |
3469bbbe MD |
930 | lib_unregister_callsites(lib); |
931 | DBG("just unregistered a tracepoints section from %p", | |
932 | lib->tracepoints_start); | |
933 | free(lib); | |
934 | break; | |
24b6668c | 935 | } |
8792fbae | 936 | pthread_mutex_unlock(&tracepoint_mutex); |
474d745f PMF |
937 | return 0; |
938 | } | |
b27f8e75 | 939 | |
5517d34d MD |
940 | /* |
941 | * Report in debug message whether the compiler correctly supports weak | |
942 | * hidden symbols. This test checks that the address associated with two | |
943 | * weak symbols with hidden visibility is the same when declared within | |
944 | * two compile units part of the same module. | |
945 | */ | |
946 | static void check_weak_hidden(void) | |
947 | { | |
b0e63efd MD |
948 | DBG("Your compiler treats weak symbols with hidden visibility for integer objects as %s between compile units part of the same module.", |
949 | &__tracepoint_test_symbol1 == lttng_ust_tp_check_weak_hidden1() ? | |
950 | "SAME address" : | |
951 | "DIFFERENT addresses"); | |
952 | DBG("Your compiler treats weak symbols with hidden visibility for pointer objects as %s between compile units part of the same module.", | |
953 | &__tracepoint_test_symbol2 == lttng_ust_tp_check_weak_hidden2() ? | |
954 | "SAME address" : | |
955 | "DIFFERENT addresses"); | |
956 | DBG("Your compiler treats weak symbols with hidden visibility for 24-byte structure objects as %s between compile units part of the same module.", | |
957 | &__tracepoint_test_symbol3 == lttng_ust_tp_check_weak_hidden3() ? | |
958 | "SAME address" : | |
959 | "DIFFERENT addresses"); | |
5517d34d MD |
960 | } |
961 | ||
25afb7ac | 962 | void lttng_ust_tp_init(void) |
b27f8e75 | 963 | { |
edaa1431 MD |
964 | if (uatomic_xchg(&initialized, 1) == 1) |
965 | return; | |
c6e6343c | 966 | lttng_ust_logging_init(); |
fca97dfd | 967 | lttng_ust_common_ctor(); |
5517d34d | 968 | check_weak_hidden(); |
b27f8e75 MD |
969 | } |
970 | ||
25afb7ac | 971 | void lttng_ust_tp_exit(void) |
b27f8e75 | 972 | { |
17dfb34b | 973 | initialized = 0; |
b27f8e75 | 974 | } |
40b2b5a4 MD |
975 | |
976 | /* | |
977 | * Create the wrapper symbols. | |
978 | */ | |
10544ee8 MD |
979 | #undef tp_rcu_read_lock |
980 | #undef tp_rcu_read_unlock | |
981 | #undef tp_rcu_dereference | |
40b2b5a4 | 982 | |
4b4a1337 | 983 | void tp_rcu_read_lock(void); |
10544ee8 | 984 | void tp_rcu_read_lock(void) |
40b2b5a4 | 985 | { |
10544ee8 | 986 | lttng_ust_urcu_read_lock(); |
40b2b5a4 MD |
987 | } |
988 | ||
4b4a1337 | 989 | void tp_rcu_read_unlock(void); |
10544ee8 | 990 | void tp_rcu_read_unlock(void) |
40b2b5a4 | 991 | { |
10544ee8 | 992 | lttng_ust_urcu_read_unlock(); |
40b2b5a4 MD |
993 | } |
994 | ||
4b4a1337 | 995 | void *tp_rcu_dereference_sym(void *p); |
10544ee8 | 996 | void *tp_rcu_dereference_sym(void *p) |
40b2b5a4 | 997 | { |
10544ee8 | 998 | return lttng_ust_rcu_dereference(p); |
40b2b5a4 | 999 | } |
0fd0de10 FD |
1000 | |
1001 | /* | |
1002 | * Programs that have threads that survive after they exit, and therefore call | |
1003 | * library destructors, should disable the tracepoint destructors by calling | |
1004 | * tp_disable_destructors(). This will leak the tracepoint | |
1005 | * instrumentation library shared object, leaving its teardown to the operating | |
1006 | * system process teardown. | |
1007 | * | |
1008 | * To access and/or modify this value, users need to use a combination of | |
1009 | * dlopen(3) and dlsym(3) to get an handle on the | |
1010 | * tp_disable_destructors and tp_get_destructors_state symbols below. | |
1011 | */ | |
4b4a1337 | 1012 | void tp_disable_destructors(void); |
0fd0de10 FD |
1013 | void tp_disable_destructors(void) |
1014 | { | |
1015 | uatomic_set(&tracepoint_destructors_state, 0); | |
1016 | } | |
1017 | ||
1018 | /* | |
1019 | * Returns 1 if the destructors are enabled and should be executed. | |
1020 | * Returns 0 if the destructors are disabled. | |
1021 | */ | |
4b4a1337 | 1022 | int tp_get_destructors_state(void); |
0fd0de10 FD |
1023 | int tp_get_destructors_state(void) |
1024 | { | |
1025 | return uatomic_read(&tracepoint_destructors_state); | |
1026 | } |