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> |
d6ddec3f | 29 | #include <urcu/urcu-bp.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 | ||
5e6df7ea | 154 | /* coverity[+alloc] */ |
efa2c591 | 155 | static void *allocate_probes(int count) |
f99be407 | 156 | { |
1a206094 SM |
157 | struct tp_probes *p = |
158 | zmalloc(count * sizeof(struct lttng_ust_tracepoint_probe) | |
159 | + sizeof(struct tp_probes)); | |
f99be407 PMF |
160 | return p == NULL ? NULL : p->probes; |
161 | } | |
162 | ||
5e6df7ea | 163 | /* coverity[+free : arg-0] */ |
efa2c591 | 164 | static void release_probes(void *old) |
f99be407 PMF |
165 | { |
166 | if (old) { | |
b728d87e | 167 | struct tp_probes *tp_probes = caa_container_of(old, |
f99be407 | 168 | struct tp_probes, probes[0]); |
d6ddec3f | 169 | urcu_bp_synchronize_rcu(); |
909bc43f | 170 | free(tp_probes); |
f99be407 PMF |
171 | } |
172 | } | |
173 | ||
174 | static void debug_print_probes(struct tracepoint_entry *entry) | |
175 | { | |
176 | int i; | |
177 | ||
9dec086e | 178 | if (!tracepoint_debug || !entry->probes) |
f99be407 PMF |
179 | return; |
180 | ||
9dec086e NC |
181 | for (i = 0; entry->probes[i].func; i++) |
182 | DBG("Probe %d : %p", i, entry->probes[i].func); | |
f99be407 PMF |
183 | } |
184 | ||
185 | static void * | |
9dec086e | 186 | tracepoint_entry_add_probe(struct tracepoint_entry *entry, |
fbdeb5ec | 187 | void (*probe)(void), void *data) |
f99be407 PMF |
188 | { |
189 | int nr_probes = 0; | |
1a206094 | 190 | struct lttng_ust_tracepoint_probe *old, *new; |
f99be407 | 191 | |
d7509147 MD |
192 | if (!probe) { |
193 | WARN_ON(1); | |
194 | return ERR_PTR(-EINVAL); | |
195 | } | |
f99be407 | 196 | debug_print_probes(entry); |
9dec086e | 197 | old = entry->probes; |
f99be407 PMF |
198 | if (old) { |
199 | /* (N -> N+1), (N != 0, 1) probes */ | |
9dec086e NC |
200 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) |
201 | if (old[nr_probes].func == probe && | |
202 | old[nr_probes].data == data) | |
f99be407 PMF |
203 | return ERR_PTR(-EEXIST); |
204 | } | |
205 | /* + 2 : one for new probe, one for NULL func */ | |
206 | new = allocate_probes(nr_probes + 2); | |
207 | if (new == NULL) | |
208 | return ERR_PTR(-ENOMEM); | |
209 | if (old) | |
1a206094 SM |
210 | memcpy(new, old, |
211 | nr_probes * sizeof(struct lttng_ust_tracepoint_probe)); | |
9dec086e NC |
212 | new[nr_probes].func = probe; |
213 | new[nr_probes].data = data; | |
214 | new[nr_probes + 1].func = NULL; | |
f99be407 | 215 | entry->refcount = nr_probes + 1; |
9dec086e | 216 | entry->probes = new; |
f99be407 PMF |
217 | debug_print_probes(entry); |
218 | return old; | |
219 | } | |
220 | ||
221 | static void * | |
fbdeb5ec MD |
222 | tracepoint_entry_remove_probe(struct tracepoint_entry *entry, |
223 | void (*probe)(void), void *data) | |
f99be407 PMF |
224 | { |
225 | int nr_probes = 0, nr_del = 0, i; | |
1a206094 | 226 | struct lttng_ust_tracepoint_probe *old, *new; |
f99be407 | 227 | |
9dec086e | 228 | old = entry->probes; |
f99be407 PMF |
229 | |
230 | if (!old) | |
231 | return ERR_PTR(-ENOENT); | |
232 | ||
233 | debug_print_probes(entry); | |
234 | /* (N -> M), (N > 1, M >= 0) probes */ | |
956c6fab MD |
235 | if (probe) { |
236 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) { | |
237 | if (old[nr_probes].func == probe && | |
238 | old[nr_probes].data == data) | |
239 | nr_del++; | |
240 | } | |
f99be407 PMF |
241 | } |
242 | ||
243 | if (nr_probes - nr_del == 0) { | |
244 | /* N -> 0, (N > 1) */ | |
9dec086e | 245 | entry->probes = NULL; |
f99be407 PMF |
246 | entry->refcount = 0; |
247 | debug_print_probes(entry); | |
248 | return old; | |
249 | } else { | |
250 | int j = 0; | |
251 | /* N -> M, (N > 1, M > 0) */ | |
252 | /* + 1 for NULL */ | |
253 | new = allocate_probes(nr_probes - nr_del + 1); | |
254 | if (new == NULL) | |
255 | return ERR_PTR(-ENOMEM); | |
9dec086e | 256 | for (i = 0; old[i].func; i++) |
956c6fab | 257 | if (old[i].func != probe || old[i].data != data) |
f99be407 | 258 | new[j++] = old[i]; |
9dec086e | 259 | new[nr_probes - nr_del].func = NULL; |
f99be407 | 260 | entry->refcount = nr_probes - nr_del; |
9dec086e | 261 | entry->probes = new; |
f99be407 PMF |
262 | } |
263 | debug_print_probes(entry); | |
264 | return old; | |
265 | } | |
266 | ||
267 | /* | |
268 | * Get tracepoint if the tracepoint is present in the tracepoint hash table. | |
8792fbae | 269 | * Must be called with tracepoint mutex held. |
f99be407 PMF |
270 | * Returns NULL if not present. |
271 | */ | |
272 | static struct tracepoint_entry *get_tracepoint(const char *name) | |
273 | { | |
10c56168 DG |
274 | struct cds_hlist_head *head; |
275 | struct cds_hlist_node *node; | |
f99be407 | 276 | struct tracepoint_entry *e; |
ff412fb5 MD |
277 | size_t name_len = strlen(name); |
278 | uint32_t hash; | |
f99be407 | 279 | |
ff412fb5 MD |
280 | if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { |
281 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); | |
282 | name_len = LTTNG_UST_SYM_NAME_LEN - 1; | |
283 | } | |
284 | hash = jhash(name, name_len, 0); | |
f99be407 | 285 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
10c56168 | 286 | cds_hlist_for_each_entry(e, node, head, hlist) { |
ff412fb5 | 287 | if (!strncmp(name, e->name, LTTNG_UST_SYM_NAME_LEN - 1)) |
f99be407 PMF |
288 | return e; |
289 | } | |
290 | return NULL; | |
291 | } | |
292 | ||
293 | /* | |
294 | * Add the tracepoint to the tracepoint hash table. Must be called with | |
8792fbae | 295 | * tracepoint mutex held. |
f99be407 | 296 | */ |
67e5f391 MD |
297 | static struct tracepoint_entry *add_tracepoint(const char *name, |
298 | const char *signature) | |
f99be407 | 299 | { |
10c56168 DG |
300 | struct cds_hlist_head *head; |
301 | struct cds_hlist_node *node; | |
f99be407 | 302 | struct tracepoint_entry *e; |
ff412fb5 | 303 | size_t name_len = strlen(name); |
2c05c691 FD |
304 | size_t sig_len = strlen(signature); |
305 | size_t sig_off, name_off; | |
ff412fb5 | 306 | uint32_t hash; |
f99be407 | 307 | |
ff412fb5 MD |
308 | if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { |
309 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); | |
310 | name_len = LTTNG_UST_SYM_NAME_LEN - 1; | |
311 | } | |
312 | hash = jhash(name, name_len, 0); | |
f99be407 | 313 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
10c56168 | 314 | cds_hlist_for_each_entry(e, node, head, hlist) { |
ff412fb5 | 315 | if (!strncmp(name, e->name, LTTNG_UST_SYM_NAME_LEN - 1)) { |
c1f20530 | 316 | DBG("tracepoint %s busy", name); |
f99be407 PMF |
317 | return ERR_PTR(-EEXIST); /* Already there */ |
318 | } | |
319 | } | |
2c05c691 | 320 | |
f99be407 | 321 | /* |
2c05c691 FD |
322 | * Using zmalloc here to allocate a variable length elements: name and |
323 | * signature. Could cause some memory fragmentation if overused. | |
f99be407 | 324 | */ |
2c05c691 FD |
325 | name_off = sizeof(struct tracepoint_entry); |
326 | sig_off = name_off + name_len + 1; | |
327 | ||
328 | e = zmalloc(sizeof(struct tracepoint_entry) + name_len + 1 + sig_len + 1); | |
f99be407 PMF |
329 | if (!e) |
330 | return ERR_PTR(-ENOMEM); | |
2c05c691 FD |
331 | e->name = (char *) e + name_off; |
332 | memcpy(e->name, name, name_len + 1); | |
ff412fb5 | 333 | e->name[name_len] = '\0'; |
2c05c691 FD |
334 | |
335 | e->signature = (char *) e + sig_off; | |
336 | memcpy(e->signature, signature, sig_len + 1); | |
337 | e->signature[sig_len] = '\0'; | |
338 | ||
9dec086e | 339 | e->probes = NULL; |
f99be407 | 340 | e->refcount = 0; |
8a7ad54b | 341 | e->callsite_refcount = 0; |
2c05c691 | 342 | |
10c56168 | 343 | cds_hlist_add_head(&e->hlist, head); |
f99be407 PMF |
344 | return e; |
345 | } | |
346 | ||
347 | /* | |
348 | * Remove the tracepoint from the tracepoint hash table. Must be called with | |
8792fbae | 349 | * tracepoint mutex held. |
f99be407 | 350 | */ |
efa2c591 | 351 | static void remove_tracepoint(struct tracepoint_entry *e) |
f99be407 | 352 | { |
10c56168 | 353 | cds_hlist_del(&e->hlist); |
909bc43f | 354 | free(e); |
f99be407 PMF |
355 | } |
356 | ||
357 | /* | |
358 | * Sets the probe callback corresponding to one tracepoint. | |
359 | */ | |
360 | static void set_tracepoint(struct tracepoint_entry **entry, | |
1a206094 | 361 | struct lttng_ust_tracepoint *elem, int active) |
f99be407 | 362 | { |
ff412fb5 | 363 | WARN_ON(strncmp((*entry)->name, elem->name, LTTNG_UST_SYM_NAME_LEN - 1) != 0); |
67e5f391 MD |
364 | /* |
365 | * Check that signatures match before connecting a probe to a | |
366 | * tracepoint. Warn the user if they don't. | |
367 | */ | |
368 | if (strcmp(elem->signature, (*entry)->signature) != 0) { | |
369 | static int warned = 0; | |
370 | ||
371 | /* Only print once, don't flood console. */ | |
372 | if (!warned) { | |
373 | WARN("Tracepoint signature mismatch, not enabling one or more tracepoints. Ensure that the tracepoint probes prototypes match the application."); | |
374 | WARN("Tracepoint \"%s\" signatures: call: \"%s\" vs probe: \"%s\".", | |
375 | elem->name, elem->signature, (*entry)->signature); | |
376 | warned = 1; | |
377 | } | |
378 | /* Don't accept connecting non-matching signatures. */ | |
379 | return; | |
380 | } | |
f99be407 PMF |
381 | |
382 | /* | |
0222e121 | 383 | * rcu_assign_pointer has a cmm_smp_wmb() which makes sure that the new |
f99be407 PMF |
384 | * probe callbacks array is consistent before setting a pointer to it. |
385 | * This array is referenced by __DO_TRACE from | |
0222e121 | 386 | * include/linux/tracepoints.h. A matching cmm_smp_read_barrier_depends() |
f99be407 PMF |
387 | * is used. |
388 | */ | |
9dec086e | 389 | rcu_assign_pointer(elem->probes, (*entry)->probes); |
c082d14b | 390 | CMM_STORE_SHARED(elem->state, active); |
f99be407 PMF |
391 | } |
392 | ||
393 | /* | |
394 | * Disable a tracepoint and its probe callback. | |
395 | * Note: only waiting an RCU period after setting elem->call to the empty | |
396 | * function insures that the original callback is not used anymore. This insured | |
397 | * by preempt_disable around the call site. | |
398 | */ | |
1a206094 | 399 | static void disable_tracepoint(struct lttng_ust_tracepoint *elem) |
f99be407 | 400 | { |
c082d14b | 401 | CMM_STORE_SHARED(elem->state, 0); |
9dec086e | 402 | rcu_assign_pointer(elem->probes, NULL); |
f99be407 PMF |
403 | } |
404 | ||
33f8ed87 MD |
405 | /* |
406 | * Add the callsite to the callsite hash table. Must be called with | |
407 | * tracepoint mutex held. | |
408 | */ | |
1a206094 | 409 | static void add_callsite(struct tracepoint_lib * lib, struct lttng_ust_tracepoint *tp) |
33f8ed87 MD |
410 | { |
411 | struct cds_hlist_head *head; | |
412 | struct callsite_entry *e; | |
413 | const char *name = tp->name; | |
414 | size_t name_len = strlen(name); | |
415 | uint32_t hash; | |
8a7ad54b | 416 | struct tracepoint_entry *tp_entry; |
33f8ed87 MD |
417 | |
418 | if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { | |
419 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); | |
420 | name_len = LTTNG_UST_SYM_NAME_LEN - 1; | |
421 | } | |
422 | hash = jhash(name, name_len, 0); | |
423 | head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)]; | |
424 | e = zmalloc(sizeof(struct callsite_entry)); | |
d6297168 MD |
425 | if (!e) { |
426 | PERROR("Unable to add callsite for tracepoint \"%s\"", name); | |
427 | return; | |
428 | } | |
33f8ed87 MD |
429 | cds_hlist_add_head(&e->hlist, head); |
430 | e->tp = tp; | |
431 | cds_list_add(&e->node, &lib->callsites); | |
8a7ad54b IJ |
432 | |
433 | tp_entry = get_tracepoint(name); | |
434 | if (!tp_entry) | |
435 | return; | |
436 | tp_entry->callsite_refcount++; | |
2c05c691 | 437 | e->tp_entry_callsite_ref = true; |
33f8ed87 MD |
438 | } |
439 | ||
440 | /* | |
441 | * Remove the callsite from the callsite hash table and from lib | |
442 | * callsite list. Must be called with tracepoint mutex held. | |
443 | */ | |
444 | static void remove_callsite(struct callsite_entry *e) | |
445 | { | |
8a7ad54b IJ |
446 | struct tracepoint_entry *tp_entry; |
447 | ||
448 | tp_entry = get_tracepoint(e->tp->name); | |
449 | if (tp_entry) { | |
2c05c691 FD |
450 | if (e->tp_entry_callsite_ref) |
451 | tp_entry->callsite_refcount--; | |
8a7ad54b IJ |
452 | if (tp_entry->callsite_refcount == 0) |
453 | disable_tracepoint(e->tp); | |
454 | } | |
33f8ed87 MD |
455 | cds_hlist_del(&e->hlist); |
456 | cds_list_del(&e->node); | |
457 | free(e); | |
458 | } | |
459 | ||
3469bbbe MD |
460 | /* |
461 | * Enable/disable all callsites based on the state of a specific | |
462 | * tracepoint entry. | |
463 | * Must be called with tracepoint mutex held. | |
464 | */ | |
465 | static void tracepoint_sync_callsites(const char *name) | |
466 | { | |
467 | struct cds_hlist_head *head; | |
468 | struct cds_hlist_node *node; | |
469 | struct callsite_entry *e; | |
470 | size_t name_len = strlen(name); | |
471 | uint32_t hash; | |
472 | struct tracepoint_entry *tp_entry; | |
473 | ||
474 | tp_entry = get_tracepoint(name); | |
475 | if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { | |
476 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); | |
477 | name_len = LTTNG_UST_SYM_NAME_LEN - 1; | |
478 | } | |
479 | hash = jhash(name, name_len, 0); | |
480 | head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)]; | |
481 | cds_hlist_for_each_entry(e, node, head, hlist) { | |
1a206094 | 482 | struct lttng_ust_tracepoint *tp = e->tp; |
3469bbbe MD |
483 | |
484 | if (strncmp(name, tp->name, LTTNG_UST_SYM_NAME_LEN - 1)) | |
485 | continue; | |
486 | if (tp_entry) { | |
2c05c691 FD |
487 | if (!e->tp_entry_callsite_ref) { |
488 | tp_entry->callsite_refcount++; | |
489 | e->tp_entry_callsite_ref = true; | |
490 | } | |
3469bbbe MD |
491 | set_tracepoint(&tp_entry, tp, |
492 | !!tp_entry->refcount); | |
493 | } else { | |
494 | disable_tracepoint(tp); | |
2c05c691 | 495 | e->tp_entry_callsite_ref = false; |
3469bbbe MD |
496 | } |
497 | } | |
498 | } | |
499 | ||
f99be407 PMF |
500 | /** |
501 | * tracepoint_update_probe_range - Update a probe range | |
502 | * @begin: beginning of the range | |
503 | * @end: end of the range | |
504 | * | |
505 | * Updates the probe callback corresponding to a range of tracepoints. | |
506 | */ | |
b27f8e75 | 507 | static |
1a206094 SM |
508 | void tracepoint_update_probe_range(struct lttng_ust_tracepoint * const *begin, |
509 | struct lttng_ust_tracepoint * const *end) | |
f99be407 | 510 | { |
1a206094 | 511 | struct lttng_ust_tracepoint * const *iter; |
f99be407 PMF |
512 | struct tracepoint_entry *mark_entry; |
513 | ||
f99be407 | 514 | for (iter = begin; iter < end; iter++) { |
f08ebbe2 MD |
515 | if (!*iter) |
516 | continue; /* skip dummy */ | |
f218ff28 MD |
517 | if (!(*iter)->name) { |
518 | disable_tracepoint(*iter); | |
9dec086e NC |
519 | continue; |
520 | } | |
f218ff28 | 521 | mark_entry = get_tracepoint((*iter)->name); |
f99be407 | 522 | if (mark_entry) { |
f218ff28 | 523 | set_tracepoint(&mark_entry, *iter, |
f99be407 PMF |
524 | !!mark_entry->refcount); |
525 | } else { | |
f218ff28 | 526 | disable_tracepoint(*iter); |
f99be407 PMF |
527 | } |
528 | } | |
f99be407 PMF |
529 | } |
530 | ||
5da10905 | 531 | static void lib_update_tracepoints(struct tracepoint_lib *lib) |
772030fe | 532 | { |
5da10905 MD |
533 | tracepoint_update_probe_range(lib->tracepoints_start, |
534 | lib->tracepoints_start + lib->tracepoints_count); | |
772030fe PMF |
535 | } |
536 | ||
3469bbbe MD |
537 | static void lib_register_callsites(struct tracepoint_lib *lib) |
538 | { | |
1a206094 SM |
539 | struct lttng_ust_tracepoint * const *begin; |
540 | struct lttng_ust_tracepoint * const *end; | |
541 | struct lttng_ust_tracepoint * const *iter; | |
3469bbbe MD |
542 | |
543 | begin = lib->tracepoints_start; | |
544 | end = lib->tracepoints_start + lib->tracepoints_count; | |
545 | ||
546 | for (iter = begin; iter < end; iter++) { | |
547 | if (!*iter) | |
548 | continue; /* skip dummy */ | |
549 | if (!(*iter)->name) { | |
550 | continue; | |
551 | } | |
60d87029 | 552 | add_callsite(lib, *iter); |
3469bbbe MD |
553 | } |
554 | } | |
555 | ||
556 | static void lib_unregister_callsites(struct tracepoint_lib *lib) | |
557 | { | |
558 | struct callsite_entry *callsite, *tmp; | |
559 | ||
560 | cds_list_for_each_entry_safe(callsite, tmp, &lib->callsites, node) | |
561 | remove_callsite(callsite); | |
562 | } | |
563 | ||
f99be407 PMF |
564 | /* |
565 | * Update probes, removing the faulty probes. | |
566 | */ | |
567 | static void tracepoint_update_probes(void) | |
568 | { | |
5da10905 MD |
569 | struct tracepoint_lib *lib; |
570 | ||
b27f8e75 | 571 | /* tracepoints registered from libraries and executable. */ |
5da10905 MD |
572 | cds_list_for_each_entry(lib, &libs, list) |
573 | lib_update_tracepoints(lib); | |
f99be407 PMF |
574 | } |
575 | ||
1a206094 | 576 | static struct lttng_ust_tracepoint_probe * |
fbdeb5ec | 577 | tracepoint_add_probe(const char *name, void (*probe)(void), void *data, |
67e5f391 | 578 | const char *signature) |
f99be407 PMF |
579 | { |
580 | struct tracepoint_entry *entry; | |
1a206094 | 581 | struct lttng_ust_tracepoint_probe *old; |
f99be407 PMF |
582 | |
583 | entry = get_tracepoint(name); | |
2c05c691 FD |
584 | if (entry) { |
585 | if (strcmp(entry->signature, signature) != 0) { | |
586 | ERR("Tracepoint and probe signature do not match."); | |
587 | return ERR_PTR(-EINVAL); | |
588 | } | |
589 | } else { | |
67e5f391 | 590 | entry = add_tracepoint(name, signature); |
f99be407 | 591 | if (IS_ERR(entry)) |
1a206094 | 592 | return (struct lttng_ust_tracepoint_probe *)entry; |
f99be407 | 593 | } |
9dec086e | 594 | old = tracepoint_entry_add_probe(entry, probe, data); |
f99be407 PMF |
595 | if (IS_ERR(old) && !entry->refcount) |
596 | remove_tracepoint(entry); | |
597 | return old; | |
598 | } | |
599 | ||
baa1e0bc MD |
600 | static void tracepoint_release_queue_add_old_probes(void *old) |
601 | { | |
602 | release_queue_need_update = 1; | |
603 | if (old) { | |
604 | struct tp_probes *tp_probes = caa_container_of(old, | |
605 | struct tp_probes, probes[0]); | |
606 | cds_list_add(&tp_probes->u.list, &release_queue); | |
607 | } | |
608 | } | |
609 | ||
f99be407 | 610 | /** |
81614639 | 611 | * __tracepoint_probe_register - Connect a probe to a tracepoint |
f99be407 PMF |
612 | * @name: tracepoint name |
613 | * @probe: probe handler | |
614 | * | |
615 | * Returns 0 if ok, error value on error. | |
616 | * The probe address must at least be aligned on the architecture pointer size. | |
8792fbae | 617 | * Called with the tracepoint mutex held. |
f99be407 | 618 | */ |
fbdeb5ec MD |
619 | int __tracepoint_probe_register(const char *name, void (*probe)(void), |
620 | void *data, const char *signature) | |
f99be407 PMF |
621 | { |
622 | void *old; | |
8792fbae | 623 | int ret = 0; |
f99be407 | 624 | |
05780d81 MD |
625 | DBG("Registering probe to tracepoint %s", name); |
626 | ||
8792fbae | 627 | pthread_mutex_lock(&tracepoint_mutex); |
67e5f391 | 628 | old = tracepoint_add_probe(name, probe, data, signature); |
8792fbae MD |
629 | if (IS_ERR(old)) { |
630 | ret = PTR_ERR(old); | |
631 | goto end; | |
632 | } | |
f99be407 | 633 | |
3469bbbe | 634 | tracepoint_sync_callsites(name); |
f99be407 | 635 | release_probes(old); |
8792fbae MD |
636 | end: |
637 | pthread_mutex_unlock(&tracepoint_mutex); | |
638 | return ret; | |
f99be407 | 639 | } |
f99be407 | 640 | |
baa1e0bc MD |
641 | /* |
642 | * Caller needs to invoke __tracepoint_probe_release_queue() after | |
643 | * calling __tracepoint_probe_register_queue_release() one or multiple | |
644 | * times to ensure it does not leak memory. | |
645 | */ | |
646 | int __tracepoint_probe_register_queue_release(const char *name, | |
647 | void (*probe)(void), void *data, const char *signature) | |
648 | { | |
649 | void *old; | |
650 | int ret = 0; | |
651 | ||
652 | DBG("Registering probe to tracepoint %s. Queuing release.", name); | |
653 | ||
654 | pthread_mutex_lock(&tracepoint_mutex); | |
655 | old = tracepoint_add_probe(name, probe, data, signature); | |
656 | if (IS_ERR(old)) { | |
657 | ret = PTR_ERR(old); | |
658 | goto end; | |
659 | } | |
660 | ||
661 | tracepoint_sync_callsites(name); | |
662 | tracepoint_release_queue_add_old_probes(old); | |
663 | end: | |
664 | pthread_mutex_unlock(&tracepoint_mutex); | |
665 | return ret; | |
666 | } | |
667 | ||
fbdeb5ec MD |
668 | static void *tracepoint_remove_probe(const char *name, void (*probe)(void), |
669 | void *data) | |
f99be407 PMF |
670 | { |
671 | struct tracepoint_entry *entry; | |
672 | void *old; | |
673 | ||
674 | entry = get_tracepoint(name); | |
675 | if (!entry) | |
676 | return ERR_PTR(-ENOENT); | |
9dec086e | 677 | old = tracepoint_entry_remove_probe(entry, probe, data); |
f99be407 PMF |
678 | if (IS_ERR(old)) |
679 | return old; | |
680 | if (!entry->refcount) | |
681 | remove_tracepoint(entry); | |
682 | return old; | |
683 | } | |
684 | ||
685 | /** | |
686 | * tracepoint_probe_unregister - Disconnect a probe from a tracepoint | |
687 | * @name: tracepoint name | |
688 | * @probe: probe function pointer | |
9dec086e | 689 | * @probe: probe data pointer |
f99be407 | 690 | */ |
fbdeb5ec MD |
691 | int __tracepoint_probe_unregister(const char *name, void (*probe)(void), |
692 | void *data) | |
f99be407 PMF |
693 | { |
694 | void *old; | |
8792fbae | 695 | int ret = 0; |
f99be407 | 696 | |
05780d81 MD |
697 | DBG("Un-registering probe from tracepoint %s", name); |
698 | ||
8792fbae | 699 | pthread_mutex_lock(&tracepoint_mutex); |
9dec086e | 700 | old = tracepoint_remove_probe(name, probe, data); |
8792fbae MD |
701 | if (IS_ERR(old)) { |
702 | ret = PTR_ERR(old); | |
703 | goto end; | |
704 | } | |
3469bbbe | 705 | tracepoint_sync_callsites(name); |
f99be407 | 706 | release_probes(old); |
8792fbae MD |
707 | end: |
708 | pthread_mutex_unlock(&tracepoint_mutex); | |
709 | return ret; | |
f99be407 | 710 | } |
f99be407 | 711 | |
baa1e0bc MD |
712 | /* |
713 | * Caller needs to invoke __tracepoint_probe_release_queue() after | |
714 | * calling __tracepoint_probe_unregister_queue_release() one or multiple | |
715 | * times to ensure it does not leak memory. | |
716 | */ | |
717 | int __tracepoint_probe_unregister_queue_release(const char *name, | |
718 | void (*probe)(void), void *data) | |
719 | { | |
720 | void *old; | |
721 | int ret = 0; | |
722 | ||
723 | DBG("Un-registering probe from tracepoint %s. Queuing release.", name); | |
724 | ||
725 | pthread_mutex_lock(&tracepoint_mutex); | |
726 | old = tracepoint_remove_probe(name, probe, data); | |
727 | if (IS_ERR(old)) { | |
728 | ret = PTR_ERR(old); | |
729 | goto end; | |
730 | } | |
731 | tracepoint_sync_callsites(name); | |
732 | tracepoint_release_queue_add_old_probes(old); | |
733 | end: | |
734 | pthread_mutex_unlock(&tracepoint_mutex); | |
735 | return ret; | |
736 | } | |
737 | ||
738 | void __tracepoint_probe_prune_release_queue(void) | |
739 | { | |
740 | CDS_LIST_HEAD(release_probes); | |
741 | struct tp_probes *pos, *next; | |
742 | ||
743 | DBG("Release queue of unregistered tracepoint probes."); | |
744 | ||
745 | pthread_mutex_lock(&tracepoint_mutex); | |
746 | if (!release_queue_need_update) | |
747 | goto end; | |
748 | if (!cds_list_empty(&release_queue)) | |
749 | cds_list_replace_init(&release_queue, &release_probes); | |
750 | release_queue_need_update = 0; | |
751 | ||
752 | /* Wait for grace period between all sync_callsites and free. */ | |
d6ddec3f | 753 | urcu_bp_synchronize_rcu(); |
baa1e0bc MD |
754 | |
755 | cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) { | |
756 | cds_list_del(&pos->u.list); | |
757 | free(pos); | |
758 | } | |
759 | end: | |
760 | pthread_mutex_unlock(&tracepoint_mutex); | |
761 | } | |
762 | ||
f99be407 PMF |
763 | static void tracepoint_add_old_probes(void *old) |
764 | { | |
765 | need_update = 1; | |
766 | if (old) { | |
b728d87e | 767 | struct tp_probes *tp_probes = caa_container_of(old, |
f99be407 | 768 | struct tp_probes, probes[0]); |
0222e121 | 769 | cds_list_add(&tp_probes->u.list, &old_probes); |
f99be407 PMF |
770 | } |
771 | } | |
772 | ||
773 | /** | |
774 | * tracepoint_probe_register_noupdate - register a probe but not connect | |
775 | * @name: tracepoint name | |
776 | * @probe: probe handler | |
777 | * | |
778 | * caller must call tracepoint_probe_update_all() | |
779 | */ | |
fbdeb5ec | 780 | int tracepoint_probe_register_noupdate(const char *name, void (*probe)(void), |
67e5f391 | 781 | void *data, const char *signature) |
f99be407 PMF |
782 | { |
783 | void *old; | |
8792fbae | 784 | int ret = 0; |
f99be407 | 785 | |
8792fbae | 786 | pthread_mutex_lock(&tracepoint_mutex); |
67e5f391 | 787 | old = tracepoint_add_probe(name, probe, data, signature); |
f99be407 | 788 | if (IS_ERR(old)) { |
8792fbae MD |
789 | ret = PTR_ERR(old); |
790 | goto end; | |
f99be407 PMF |
791 | } |
792 | tracepoint_add_old_probes(old); | |
8792fbae MD |
793 | end: |
794 | pthread_mutex_unlock(&tracepoint_mutex); | |
795 | return ret; | |
f99be407 | 796 | } |
f99be407 PMF |
797 | |
798 | /** | |
799 | * tracepoint_probe_unregister_noupdate - remove a probe but not disconnect | |
800 | * @name: tracepoint name | |
801 | * @probe: probe function pointer | |
802 | * | |
803 | * caller must call tracepoint_probe_update_all() | |
8792fbae | 804 | * Called with the tracepoint mutex held. |
f99be407 | 805 | */ |
fbdeb5ec | 806 | int tracepoint_probe_unregister_noupdate(const char *name, void (*probe)(void), |
9dec086e | 807 | void *data) |
f99be407 PMF |
808 | { |
809 | void *old; | |
8792fbae | 810 | int ret = 0; |
f99be407 | 811 | |
05780d81 MD |
812 | DBG("Un-registering probe from tracepoint %s", name); |
813 | ||
8792fbae | 814 | pthread_mutex_lock(&tracepoint_mutex); |
9dec086e | 815 | old = tracepoint_remove_probe(name, probe, data); |
f99be407 | 816 | if (IS_ERR(old)) { |
8792fbae MD |
817 | ret = PTR_ERR(old); |
818 | goto end; | |
f99be407 PMF |
819 | } |
820 | tracepoint_add_old_probes(old); | |
8792fbae MD |
821 | end: |
822 | pthread_mutex_unlock(&tracepoint_mutex); | |
823 | return ret; | |
f99be407 | 824 | } |
f99be407 PMF |
825 | |
826 | /** | |
827 | * tracepoint_probe_update_all - update tracepoints | |
828 | */ | |
829 | void tracepoint_probe_update_all(void) | |
830 | { | |
0222e121 | 831 | CDS_LIST_HEAD(release_probes); |
f99be407 PMF |
832 | struct tp_probes *pos, *next; |
833 | ||
8792fbae | 834 | pthread_mutex_lock(&tracepoint_mutex); |
f99be407 | 835 | if (!need_update) { |
8792fbae | 836 | goto end; |
f99be407 | 837 | } |
0222e121 MD |
838 | if (!cds_list_empty(&old_probes)) |
839 | cds_list_replace_init(&old_probes, &release_probes); | |
f99be407 | 840 | need_update = 0; |
f99be407 PMF |
841 | |
842 | tracepoint_update_probes(); | |
baa1e0bc | 843 | /* Wait for grace period between update_probes and free. */ |
d6ddec3f | 844 | urcu_bp_synchronize_rcu(); |
0222e121 MD |
845 | cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) { |
846 | cds_list_del(&pos->u.list); | |
909bc43f | 847 | free(pos); |
f99be407 | 848 | } |
8792fbae MD |
849 | end: |
850 | pthread_mutex_unlock(&tracepoint_mutex); | |
f99be407 | 851 | } |
f99be407 | 852 | |
1a206094 | 853 | void tracepoint_set_new_tracepoint_cb(void (*cb)(struct lttng_ust_tracepoint *)) |
474d745f PMF |
854 | { |
855 | new_tracepoint_cb = cb; | |
856 | } | |
f99be407 | 857 | |
1a206094 SM |
858 | static void new_tracepoints(struct lttng_ust_tracepoint * const *start, |
859 | struct lttng_ust_tracepoint * const *end) | |
f99be407 | 860 | { |
f218ff28 | 861 | if (new_tracepoint_cb) { |
1a206094 | 862 | struct lttng_ust_tracepoint * const *t; |
f08ebbe2 | 863 | |
b27f8e75 | 864 | for (t = start; t < end; t++) { |
f08ebbe2 MD |
865 | if (*t) |
866 | new_tracepoint_cb(*t); | |
474d745f PMF |
867 | } |
868 | } | |
f99be407 | 869 | } |
f99be407 | 870 | |
1a206094 | 871 | int tracepoint_register_lib(struct lttng_ust_tracepoint * const *tracepoints_start, |
b27f8e75 | 872 | int tracepoints_count) |
474d745f | 873 | { |
b467f7a7 | 874 | struct tracepoint_lib *pl, *iter; |
474d745f | 875 | |
edaa1431 MD |
876 | init_tracepoint(); |
877 | ||
1dba3e6c | 878 | pl = (struct tracepoint_lib *) zmalloc(sizeof(struct tracepoint_lib)); |
d6297168 MD |
879 | if (!pl) { |
880 | PERROR("Unable to register tracepoint lib"); | |
881 | return -1; | |
882 | } | |
474d745f PMF |
883 | pl->tracepoints_start = tracepoints_start; |
884 | pl->tracepoints_count = tracepoints_count; | |
3469bbbe | 885 | CDS_INIT_LIST_HEAD(&pl->callsites); |
474d745f | 886 | |
8792fbae | 887 | pthread_mutex_lock(&tracepoint_mutex); |
b467f7a7 MD |
888 | /* |
889 | * We sort the libs by struct lib pointer address. | |
890 | */ | |
891 | cds_list_for_each_entry_reverse(iter, &libs, list) { | |
892 | BUG_ON(iter == pl); /* Should never be in the list twice */ | |
893 | if (iter < pl) { | |
894 | /* We belong to the location right after iter. */ | |
895 | cds_list_add(&pl->list, &iter->list); | |
896 | goto lib_added; | |
897 | } | |
898 | } | |
899 | /* We should be added at the head of the list */ | |
0222e121 | 900 | cds_list_add(&pl->list, &libs); |
b467f7a7 | 901 | lib_added: |
474d745f | 902 | new_tracepoints(tracepoints_start, tracepoints_start + tracepoints_count); |
3469bbbe | 903 | lib_register_callsites(pl); |
5da10905 | 904 | lib_update_tracepoints(pl); |
8792fbae | 905 | pthread_mutex_unlock(&tracepoint_mutex); |
474d745f | 906 | |
1fcf7ad7 MD |
907 | DBG("just registered a tracepoints section from %p and having %d tracepoints", |
908 | tracepoints_start, tracepoints_count); | |
05780d81 MD |
909 | if (ust_debug()) { |
910 | int i; | |
911 | ||
912 | for (i = 0; i < tracepoints_count; i++) { | |
913 | DBG("registered tracepoint: %s", tracepoints_start[i]->name); | |
914 | } | |
915 | } | |
9dec086e | 916 | |
474d745f PMF |
917 | return 0; |
918 | } | |
919 | ||
1a206094 | 920 | int tracepoint_unregister_lib(struct lttng_ust_tracepoint * const *tracepoints_start) |
474d745f | 921 | { |
24b6668c PMF |
922 | struct tracepoint_lib *lib; |
923 | ||
8792fbae | 924 | pthread_mutex_lock(&tracepoint_mutex); |
0222e121 | 925 | cds_list_for_each_entry(lib, &libs, list) { |
3469bbbe MD |
926 | if (lib->tracepoints_start != tracepoints_start) |
927 | continue; | |
1622ba22 | 928 | |
3469bbbe MD |
929 | cds_list_del(&lib->list); |
930 | /* | |
8a7ad54b IJ |
931 | * Unregistering a callsite also decreases the |
932 | * callsite reference count of the corresponding | |
933 | * tracepoint, and disables the tracepoint if | |
934 | * the reference count drops to zero. | |
3469bbbe | 935 | */ |
3469bbbe MD |
936 | lib_unregister_callsites(lib); |
937 | DBG("just unregistered a tracepoints section from %p", | |
938 | lib->tracepoints_start); | |
939 | free(lib); | |
940 | break; | |
24b6668c | 941 | } |
8792fbae | 942 | pthread_mutex_unlock(&tracepoint_mutex); |
474d745f PMF |
943 | return 0; |
944 | } | |
b27f8e75 | 945 | |
5517d34d MD |
946 | /* |
947 | * Report in debug message whether the compiler correctly supports weak | |
948 | * hidden symbols. This test checks that the address associated with two | |
949 | * weak symbols with hidden visibility is the same when declared within | |
950 | * two compile units part of the same module. | |
951 | */ | |
952 | static void check_weak_hidden(void) | |
953 | { | |
b0e63efd MD |
954 | DBG("Your compiler treats weak symbols with hidden visibility for integer objects as %s between compile units part of the same module.", |
955 | &__tracepoint_test_symbol1 == lttng_ust_tp_check_weak_hidden1() ? | |
956 | "SAME address" : | |
957 | "DIFFERENT addresses"); | |
958 | DBG("Your compiler treats weak symbols with hidden visibility for pointer objects as %s between compile units part of the same module.", | |
959 | &__tracepoint_test_symbol2 == lttng_ust_tp_check_weak_hidden2() ? | |
960 | "SAME address" : | |
961 | "DIFFERENT addresses"); | |
962 | DBG("Your compiler treats weak symbols with hidden visibility for 24-byte structure objects as %s between compile units part of the same module.", | |
963 | &__tracepoint_test_symbol3 == lttng_ust_tp_check_weak_hidden3() ? | |
964 | "SAME address" : | |
965 | "DIFFERENT addresses"); | |
5517d34d MD |
966 | } |
967 | ||
edaa1431 | 968 | void init_tracepoint(void) |
b27f8e75 | 969 | { |
edaa1431 MD |
970 | if (uatomic_xchg(&initialized, 1) == 1) |
971 | return; | |
5e96a467 | 972 | init_usterr(); |
5517d34d | 973 | check_weak_hidden(); |
b27f8e75 MD |
974 | } |
975 | ||
edaa1431 | 976 | void exit_tracepoint(void) |
b27f8e75 | 977 | { |
17dfb34b | 978 | initialized = 0; |
b27f8e75 | 979 | } |
40b2b5a4 MD |
980 | |
981 | /* | |
982 | * Create the wrapper symbols. | |
983 | */ | |
984 | #undef tp_rcu_read_lock_bp | |
985 | #undef tp_rcu_read_unlock_bp | |
986 | #undef tp_rcu_dereference_bp | |
987 | ||
988 | void tp_rcu_read_lock_bp(void) | |
989 | { | |
d6ddec3f | 990 | urcu_bp_read_lock(); |
40b2b5a4 MD |
991 | } |
992 | ||
993 | void tp_rcu_read_unlock_bp(void) | |
994 | { | |
d6ddec3f | 995 | urcu_bp_read_unlock(); |
40b2b5a4 MD |
996 | } |
997 | ||
998 | void *tp_rcu_dereference_sym_bp(void *p) | |
999 | { | |
d6ddec3f | 1000 | return urcu_bp_dereference(p); |
40b2b5a4 | 1001 | } |
0fd0de10 FD |
1002 | |
1003 | /* | |
1004 | * Programs that have threads that survive after they exit, and therefore call | |
1005 | * library destructors, should disable the tracepoint destructors by calling | |
1006 | * tp_disable_destructors(). This will leak the tracepoint | |
1007 | * instrumentation library shared object, leaving its teardown to the operating | |
1008 | * system process teardown. | |
1009 | * | |
1010 | * To access and/or modify this value, users need to use a combination of | |
1011 | * dlopen(3) and dlsym(3) to get an handle on the | |
1012 | * tp_disable_destructors and tp_get_destructors_state symbols below. | |
1013 | */ | |
1014 | void tp_disable_destructors(void) | |
1015 | { | |
1016 | uatomic_set(&tracepoint_destructors_state, 0); | |
1017 | } | |
1018 | ||
1019 | /* | |
1020 | * Returns 1 if the destructors are enabled and should be executed. | |
1021 | * Returns 0 if the destructors are disabled. | |
1022 | */ | |
1023 | int tp_get_destructors_state(void) | |
1024 | { | |
1025 | return uatomic_read(&tracepoint_destructors_state); | |
1026 | } |