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> |
b7ea1a1c | 29 | #include <urcu-bp.h> |
10c56168 | 30 | #include <urcu/hlist.h> |
edaa1431 | 31 | #include <urcu/uatomic.h> |
b728d87e | 32 | #include <urcu/compiler.h> |
44c72f10 MD |
33 | |
34 | #include <lttng/tracepoint.h> | |
ff412fb5 | 35 | #include <lttng/ust-abi.h> /* for LTTNG_UST_SYM_NAME_LEN */ |
44c72f10 MD |
36 | |
37 | #include <usterr-signal-safe.h> | |
35897f8b | 38 | #include <helper.h> |
474d745f | 39 | |
23c8854a | 40 | #include "tracepoint-internal.h" |
7dd08bec | 41 | #include "lttng-tracer-core.h" |
596c4223 | 42 | #include "jhash.h" |
8f3f8c99 | 43 | #include "error.h" |
b0c4126f | 44 | |
f99be407 PMF |
45 | /* Set to 1 to enable tracepoint debug output */ |
46 | static const int tracepoint_debug; | |
b27f8e75 | 47 | static int initialized; |
1a206094 | 48 | static void (*new_tracepoint_cb)(struct lttng_ust_tracepoint *); |
f99be407 | 49 | |
8792fbae MD |
50 | /* |
51 | * tracepoint_mutex nests inside UST mutex. | |
52 | * | |
53 | * Note about interaction with fork/clone: UST does not hold the | |
54 | * tracepoint mutex across fork/clone because it is either: | |
55 | * - nested within UST mutex, in which case holding the UST mutex across | |
56 | * fork/clone suffice, | |
57 | * - taken by a library constructor, which should never race with a | |
58 | * fork/clone if the application is expected to continue running with | |
59 | * the same memory layout (no following exec()). | |
60 | */ | |
61 | static pthread_mutex_t tracepoint_mutex = PTHREAD_MUTEX_INITIALIZER; | |
62 | ||
efa2c591 MD |
63 | /* |
64 | * libraries that contain tracepoints (struct tracepoint_lib). | |
8792fbae | 65 | * Protected by tracepoint mutex. |
efa2c591 | 66 | */ |
0222e121 | 67 | static CDS_LIST_HEAD(libs); |
474d745f | 68 | |
f99be407 | 69 | /* |
8792fbae | 70 | * The tracepoint mutex protects the library tracepoints, the hash table, and |
17dfb34b | 71 | * the library list. |
8792fbae | 72 | * All calls to the tracepoint API must be protected by the tracepoint mutex, |
17dfb34b | 73 | * excepts calls to tracepoint_register_lib and |
8792fbae | 74 | * tracepoint_unregister_lib, which take the tracepoint mutex themselves. |
f99be407 | 75 | */ |
f99be407 PMF |
76 | |
77 | /* | |
78 | * Tracepoint hash table, containing the active tracepoints. | |
8792fbae | 79 | * Protected by tracepoint mutex. |
f99be407 | 80 | */ |
814f7df1 | 81 | #define TRACEPOINT_HASH_BITS 12 |
f99be407 | 82 | #define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS) |
10c56168 | 83 | static struct cds_hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE]; |
f99be407 | 84 | |
b27f8e75 MD |
85 | static CDS_LIST_HEAD(old_probes); |
86 | static int need_update; | |
87 | ||
f99be407 PMF |
88 | /* |
89 | * Note about RCU : | |
90 | * It is used to to delay the free of multiple probes array until a quiescent | |
91 | * state is reached. | |
8792fbae | 92 | * Tracepoint entries modifications are protected by the tracepoint mutex. |
f99be407 PMF |
93 | */ |
94 | struct tracepoint_entry { | |
10c56168 | 95 | struct cds_hlist_node hlist; |
1a206094 | 96 | struct lttng_ust_tracepoint_probe *probes; |
f99be407 | 97 | int refcount; /* Number of times armed. 0 if disarmed. */ |
8a7ad54b | 98 | int callsite_refcount; /* how many libs use this tracepoint */ |
67e5f391 | 99 | const char *signature; |
f99be407 PMF |
100 | char name[0]; |
101 | }; | |
102 | ||
103 | struct tp_probes { | |
104 | union { | |
0222e121 | 105 | struct cds_list_head list; |
ade7037b MD |
106 | /* Field below only used for call_rcu scheme */ |
107 | /* struct rcu_head head; */ | |
f99be407 | 108 | } u; |
1a206094 | 109 | struct lttng_ust_tracepoint_probe probes[0]; |
f99be407 PMF |
110 | }; |
111 | ||
3469bbbe MD |
112 | /* |
113 | * Callsite hash table, containing the tracepoint call sites. | |
114 | * Protected by tracepoint mutex. | |
115 | */ | |
116 | #define CALLSITE_HASH_BITS 12 | |
117 | #define CALLSITE_TABLE_SIZE (1 << CALLSITE_HASH_BITS) | |
118 | static struct cds_hlist_head callsite_table[CALLSITE_TABLE_SIZE]; | |
119 | ||
120 | struct callsite_entry { | |
121 | struct cds_hlist_node hlist; /* hash table node */ | |
122 | struct cds_list_head node; /* lib list of callsites node */ | |
1a206094 | 123 | struct lttng_ust_tracepoint *tp; |
3469bbbe MD |
124 | }; |
125 | ||
5e6df7ea | 126 | /* coverity[+alloc] */ |
efa2c591 | 127 | static void *allocate_probes(int count) |
f99be407 | 128 | { |
1a206094 SM |
129 | struct tp_probes *p = |
130 | zmalloc(count * sizeof(struct lttng_ust_tracepoint_probe) | |
131 | + sizeof(struct tp_probes)); | |
f99be407 PMF |
132 | return p == NULL ? NULL : p->probes; |
133 | } | |
134 | ||
5e6df7ea | 135 | /* coverity[+free : arg-0] */ |
efa2c591 | 136 | static void release_probes(void *old) |
f99be407 PMF |
137 | { |
138 | if (old) { | |
b728d87e | 139 | struct tp_probes *tp_probes = caa_container_of(old, |
f99be407 | 140 | struct tp_probes, probes[0]); |
474d745f | 141 | synchronize_rcu(); |
909bc43f | 142 | free(tp_probes); |
f99be407 PMF |
143 | } |
144 | } | |
145 | ||
146 | static void debug_print_probes(struct tracepoint_entry *entry) | |
147 | { | |
148 | int i; | |
149 | ||
9dec086e | 150 | if (!tracepoint_debug || !entry->probes) |
f99be407 PMF |
151 | return; |
152 | ||
9dec086e NC |
153 | for (i = 0; entry->probes[i].func; i++) |
154 | DBG("Probe %d : %p", i, entry->probes[i].func); | |
f99be407 PMF |
155 | } |
156 | ||
157 | static void * | |
9dec086e | 158 | tracepoint_entry_add_probe(struct tracepoint_entry *entry, |
fbdeb5ec | 159 | void (*probe)(void), void *data) |
f99be407 PMF |
160 | { |
161 | int nr_probes = 0; | |
1a206094 | 162 | struct lttng_ust_tracepoint_probe *old, *new; |
f99be407 | 163 | |
d7509147 MD |
164 | if (!probe) { |
165 | WARN_ON(1); | |
166 | return ERR_PTR(-EINVAL); | |
167 | } | |
f99be407 | 168 | debug_print_probes(entry); |
9dec086e | 169 | old = entry->probes; |
f99be407 PMF |
170 | if (old) { |
171 | /* (N -> N+1), (N != 0, 1) probes */ | |
9dec086e NC |
172 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) |
173 | if (old[nr_probes].func == probe && | |
174 | old[nr_probes].data == data) | |
f99be407 PMF |
175 | return ERR_PTR(-EEXIST); |
176 | } | |
177 | /* + 2 : one for new probe, one for NULL func */ | |
178 | new = allocate_probes(nr_probes + 2); | |
179 | if (new == NULL) | |
180 | return ERR_PTR(-ENOMEM); | |
181 | if (old) | |
1a206094 SM |
182 | memcpy(new, old, |
183 | nr_probes * sizeof(struct lttng_ust_tracepoint_probe)); | |
9dec086e NC |
184 | new[nr_probes].func = probe; |
185 | new[nr_probes].data = data; | |
186 | new[nr_probes + 1].func = NULL; | |
f99be407 | 187 | entry->refcount = nr_probes + 1; |
9dec086e | 188 | entry->probes = new; |
f99be407 PMF |
189 | debug_print_probes(entry); |
190 | return old; | |
191 | } | |
192 | ||
193 | static void * | |
fbdeb5ec MD |
194 | tracepoint_entry_remove_probe(struct tracepoint_entry *entry, |
195 | void (*probe)(void), void *data) | |
f99be407 PMF |
196 | { |
197 | int nr_probes = 0, nr_del = 0, i; | |
1a206094 | 198 | struct lttng_ust_tracepoint_probe *old, *new; |
f99be407 | 199 | |
9dec086e | 200 | old = entry->probes; |
f99be407 PMF |
201 | |
202 | if (!old) | |
203 | return ERR_PTR(-ENOENT); | |
204 | ||
205 | debug_print_probes(entry); | |
206 | /* (N -> M), (N > 1, M >= 0) probes */ | |
956c6fab MD |
207 | if (probe) { |
208 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) { | |
209 | if (old[nr_probes].func == probe && | |
210 | old[nr_probes].data == data) | |
211 | nr_del++; | |
212 | } | |
f99be407 PMF |
213 | } |
214 | ||
215 | if (nr_probes - nr_del == 0) { | |
216 | /* N -> 0, (N > 1) */ | |
9dec086e | 217 | entry->probes = NULL; |
f99be407 PMF |
218 | entry->refcount = 0; |
219 | debug_print_probes(entry); | |
220 | return old; | |
221 | } else { | |
222 | int j = 0; | |
223 | /* N -> M, (N > 1, M > 0) */ | |
224 | /* + 1 for NULL */ | |
225 | new = allocate_probes(nr_probes - nr_del + 1); | |
226 | if (new == NULL) | |
227 | return ERR_PTR(-ENOMEM); | |
9dec086e | 228 | for (i = 0; old[i].func; i++) |
956c6fab | 229 | if (old[i].func != probe || old[i].data != data) |
f99be407 | 230 | new[j++] = old[i]; |
9dec086e | 231 | new[nr_probes - nr_del].func = NULL; |
f99be407 | 232 | entry->refcount = nr_probes - nr_del; |
9dec086e | 233 | entry->probes = new; |
f99be407 PMF |
234 | } |
235 | debug_print_probes(entry); | |
236 | return old; | |
237 | } | |
238 | ||
239 | /* | |
240 | * Get tracepoint if the tracepoint is present in the tracepoint hash table. | |
8792fbae | 241 | * Must be called with tracepoint mutex held. |
f99be407 PMF |
242 | * Returns NULL if not present. |
243 | */ | |
244 | static struct tracepoint_entry *get_tracepoint(const char *name) | |
245 | { | |
10c56168 DG |
246 | struct cds_hlist_head *head; |
247 | struct cds_hlist_node *node; | |
f99be407 | 248 | struct tracepoint_entry *e; |
ff412fb5 MD |
249 | size_t name_len = strlen(name); |
250 | uint32_t hash; | |
f99be407 | 251 | |
ff412fb5 MD |
252 | if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { |
253 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); | |
254 | name_len = LTTNG_UST_SYM_NAME_LEN - 1; | |
255 | } | |
256 | hash = jhash(name, name_len, 0); | |
f99be407 | 257 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
10c56168 | 258 | cds_hlist_for_each_entry(e, node, head, hlist) { |
ff412fb5 | 259 | if (!strncmp(name, e->name, LTTNG_UST_SYM_NAME_LEN - 1)) |
f99be407 PMF |
260 | return e; |
261 | } | |
262 | return NULL; | |
263 | } | |
264 | ||
265 | /* | |
266 | * Add the tracepoint to the tracepoint hash table. Must be called with | |
8792fbae | 267 | * tracepoint mutex held. |
f99be407 | 268 | */ |
67e5f391 MD |
269 | static struct tracepoint_entry *add_tracepoint(const char *name, |
270 | const char *signature) | |
f99be407 | 271 | { |
10c56168 DG |
272 | struct cds_hlist_head *head; |
273 | struct cds_hlist_node *node; | |
f99be407 | 274 | struct tracepoint_entry *e; |
ff412fb5 MD |
275 | size_t name_len = strlen(name); |
276 | uint32_t hash; | |
f99be407 | 277 | |
ff412fb5 MD |
278 | if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { |
279 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); | |
280 | name_len = LTTNG_UST_SYM_NAME_LEN - 1; | |
281 | } | |
282 | hash = jhash(name, name_len, 0); | |
f99be407 | 283 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
10c56168 | 284 | cds_hlist_for_each_entry(e, node, head, hlist) { |
ff412fb5 | 285 | if (!strncmp(name, e->name, LTTNG_UST_SYM_NAME_LEN - 1)) { |
c1f20530 | 286 | DBG("tracepoint %s busy", name); |
f99be407 PMF |
287 | return ERR_PTR(-EEXIST); /* Already there */ |
288 | } | |
289 | } | |
290 | /* | |
1dba3e6c | 291 | * Using zmalloc here to allocate a variable length element. Could |
f99be407 PMF |
292 | * cause some memory fragmentation if overused. |
293 | */ | |
ff412fb5 | 294 | e = zmalloc(sizeof(struct tracepoint_entry) + name_len + 1); |
f99be407 PMF |
295 | if (!e) |
296 | return ERR_PTR(-ENOMEM); | |
ff412fb5 MD |
297 | memcpy(&e->name[0], name, name_len + 1); |
298 | e->name[name_len] = '\0'; | |
9dec086e | 299 | e->probes = NULL; |
f99be407 | 300 | e->refcount = 0; |
8a7ad54b | 301 | e->callsite_refcount = 0; |
67e5f391 | 302 | e->signature = signature; |
10c56168 | 303 | cds_hlist_add_head(&e->hlist, head); |
f99be407 PMF |
304 | return e; |
305 | } | |
306 | ||
307 | /* | |
308 | * Remove the tracepoint from the tracepoint hash table. Must be called with | |
8792fbae | 309 | * tracepoint mutex held. |
f99be407 | 310 | */ |
efa2c591 | 311 | static void remove_tracepoint(struct tracepoint_entry *e) |
f99be407 | 312 | { |
10c56168 | 313 | cds_hlist_del(&e->hlist); |
909bc43f | 314 | free(e); |
f99be407 PMF |
315 | } |
316 | ||
317 | /* | |
318 | * Sets the probe callback corresponding to one tracepoint. | |
319 | */ | |
320 | static void set_tracepoint(struct tracepoint_entry **entry, | |
1a206094 | 321 | struct lttng_ust_tracepoint *elem, int active) |
f99be407 | 322 | { |
ff412fb5 | 323 | WARN_ON(strncmp((*entry)->name, elem->name, LTTNG_UST_SYM_NAME_LEN - 1) != 0); |
67e5f391 MD |
324 | /* |
325 | * Check that signatures match before connecting a probe to a | |
326 | * tracepoint. Warn the user if they don't. | |
327 | */ | |
328 | if (strcmp(elem->signature, (*entry)->signature) != 0) { | |
329 | static int warned = 0; | |
330 | ||
331 | /* Only print once, don't flood console. */ | |
332 | if (!warned) { | |
333 | WARN("Tracepoint signature mismatch, not enabling one or more tracepoints. Ensure that the tracepoint probes prototypes match the application."); | |
334 | WARN("Tracepoint \"%s\" signatures: call: \"%s\" vs probe: \"%s\".", | |
335 | elem->name, elem->signature, (*entry)->signature); | |
336 | warned = 1; | |
337 | } | |
338 | /* Don't accept connecting non-matching signatures. */ | |
339 | return; | |
340 | } | |
f99be407 PMF |
341 | |
342 | /* | |
0222e121 | 343 | * rcu_assign_pointer has a cmm_smp_wmb() which makes sure that the new |
f99be407 PMF |
344 | * probe callbacks array is consistent before setting a pointer to it. |
345 | * This array is referenced by __DO_TRACE from | |
0222e121 | 346 | * include/linux/tracepoints.h. A matching cmm_smp_read_barrier_depends() |
f99be407 PMF |
347 | * is used. |
348 | */ | |
9dec086e | 349 | rcu_assign_pointer(elem->probes, (*entry)->probes); |
f36c12ab | 350 | elem->state = active; |
f99be407 PMF |
351 | } |
352 | ||
353 | /* | |
354 | * Disable a tracepoint and its probe callback. | |
355 | * Note: only waiting an RCU period after setting elem->call to the empty | |
356 | * function insures that the original callback is not used anymore. This insured | |
357 | * by preempt_disable around the call site. | |
358 | */ | |
1a206094 | 359 | static void disable_tracepoint(struct lttng_ust_tracepoint *elem) |
f99be407 | 360 | { |
f36c12ab | 361 | elem->state = 0; |
9dec086e | 362 | rcu_assign_pointer(elem->probes, NULL); |
f99be407 PMF |
363 | } |
364 | ||
33f8ed87 MD |
365 | /* |
366 | * Add the callsite to the callsite hash table. Must be called with | |
367 | * tracepoint mutex held. | |
368 | */ | |
1a206094 | 369 | static void add_callsite(struct tracepoint_lib * lib, struct lttng_ust_tracepoint *tp) |
33f8ed87 MD |
370 | { |
371 | struct cds_hlist_head *head; | |
372 | struct callsite_entry *e; | |
373 | const char *name = tp->name; | |
374 | size_t name_len = strlen(name); | |
375 | uint32_t hash; | |
8a7ad54b | 376 | struct tracepoint_entry *tp_entry; |
33f8ed87 MD |
377 | |
378 | if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { | |
379 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); | |
380 | name_len = LTTNG_UST_SYM_NAME_LEN - 1; | |
381 | } | |
382 | hash = jhash(name, name_len, 0); | |
383 | head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)]; | |
384 | e = zmalloc(sizeof(struct callsite_entry)); | |
d6297168 MD |
385 | if (!e) { |
386 | PERROR("Unable to add callsite for tracepoint \"%s\"", name); | |
387 | return; | |
388 | } | |
33f8ed87 MD |
389 | cds_hlist_add_head(&e->hlist, head); |
390 | e->tp = tp; | |
391 | cds_list_add(&e->node, &lib->callsites); | |
8a7ad54b IJ |
392 | |
393 | tp_entry = get_tracepoint(name); | |
394 | if (!tp_entry) | |
395 | return; | |
396 | tp_entry->callsite_refcount++; | |
33f8ed87 MD |
397 | } |
398 | ||
399 | /* | |
400 | * Remove the callsite from the callsite hash table and from lib | |
401 | * callsite list. Must be called with tracepoint mutex held. | |
402 | */ | |
403 | static void remove_callsite(struct callsite_entry *e) | |
404 | { | |
8a7ad54b IJ |
405 | struct tracepoint_entry *tp_entry; |
406 | ||
407 | tp_entry = get_tracepoint(e->tp->name); | |
408 | if (tp_entry) { | |
409 | tp_entry->callsite_refcount--; | |
410 | if (tp_entry->callsite_refcount == 0) | |
411 | disable_tracepoint(e->tp); | |
412 | } | |
33f8ed87 MD |
413 | cds_hlist_del(&e->hlist); |
414 | cds_list_del(&e->node); | |
415 | free(e); | |
416 | } | |
417 | ||
3469bbbe MD |
418 | /* |
419 | * Enable/disable all callsites based on the state of a specific | |
420 | * tracepoint entry. | |
421 | * Must be called with tracepoint mutex held. | |
422 | */ | |
423 | static void tracepoint_sync_callsites(const char *name) | |
424 | { | |
425 | struct cds_hlist_head *head; | |
426 | struct cds_hlist_node *node; | |
427 | struct callsite_entry *e; | |
428 | size_t name_len = strlen(name); | |
429 | uint32_t hash; | |
430 | struct tracepoint_entry *tp_entry; | |
431 | ||
432 | tp_entry = get_tracepoint(name); | |
433 | if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { | |
434 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); | |
435 | name_len = LTTNG_UST_SYM_NAME_LEN - 1; | |
436 | } | |
437 | hash = jhash(name, name_len, 0); | |
438 | head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)]; | |
439 | cds_hlist_for_each_entry(e, node, head, hlist) { | |
1a206094 | 440 | struct lttng_ust_tracepoint *tp = e->tp; |
3469bbbe MD |
441 | |
442 | if (strncmp(name, tp->name, LTTNG_UST_SYM_NAME_LEN - 1)) | |
443 | continue; | |
444 | if (tp_entry) { | |
445 | set_tracepoint(&tp_entry, tp, | |
446 | !!tp_entry->refcount); | |
447 | } else { | |
448 | disable_tracepoint(tp); | |
449 | } | |
450 | } | |
451 | } | |
452 | ||
f99be407 PMF |
453 | /** |
454 | * tracepoint_update_probe_range - Update a probe range | |
455 | * @begin: beginning of the range | |
456 | * @end: end of the range | |
457 | * | |
458 | * Updates the probe callback corresponding to a range of tracepoints. | |
459 | */ | |
b27f8e75 | 460 | static |
1a206094 SM |
461 | void tracepoint_update_probe_range(struct lttng_ust_tracepoint * const *begin, |
462 | struct lttng_ust_tracepoint * const *end) | |
f99be407 | 463 | { |
1a206094 | 464 | struct lttng_ust_tracepoint * const *iter; |
f99be407 PMF |
465 | struct tracepoint_entry *mark_entry; |
466 | ||
f99be407 | 467 | for (iter = begin; iter < end; iter++) { |
f08ebbe2 MD |
468 | if (!*iter) |
469 | continue; /* skip dummy */ | |
f218ff28 MD |
470 | if (!(*iter)->name) { |
471 | disable_tracepoint(*iter); | |
9dec086e NC |
472 | continue; |
473 | } | |
f218ff28 | 474 | mark_entry = get_tracepoint((*iter)->name); |
f99be407 | 475 | if (mark_entry) { |
f218ff28 | 476 | set_tracepoint(&mark_entry, *iter, |
f99be407 PMF |
477 | !!mark_entry->refcount); |
478 | } else { | |
f218ff28 | 479 | disable_tracepoint(*iter); |
f99be407 PMF |
480 | } |
481 | } | |
f99be407 PMF |
482 | } |
483 | ||
5da10905 | 484 | static void lib_update_tracepoints(struct tracepoint_lib *lib) |
772030fe | 485 | { |
5da10905 MD |
486 | tracepoint_update_probe_range(lib->tracepoints_start, |
487 | lib->tracepoints_start + lib->tracepoints_count); | |
772030fe PMF |
488 | } |
489 | ||
3469bbbe MD |
490 | static void lib_register_callsites(struct tracepoint_lib *lib) |
491 | { | |
1a206094 SM |
492 | struct lttng_ust_tracepoint * const *begin; |
493 | struct lttng_ust_tracepoint * const *end; | |
494 | struct lttng_ust_tracepoint * const *iter; | |
3469bbbe MD |
495 | |
496 | begin = lib->tracepoints_start; | |
497 | end = lib->tracepoints_start + lib->tracepoints_count; | |
498 | ||
499 | for (iter = begin; iter < end; iter++) { | |
500 | if (!*iter) | |
501 | continue; /* skip dummy */ | |
502 | if (!(*iter)->name) { | |
503 | continue; | |
504 | } | |
60d87029 | 505 | add_callsite(lib, *iter); |
3469bbbe MD |
506 | } |
507 | } | |
508 | ||
509 | static void lib_unregister_callsites(struct tracepoint_lib *lib) | |
510 | { | |
511 | struct callsite_entry *callsite, *tmp; | |
512 | ||
513 | cds_list_for_each_entry_safe(callsite, tmp, &lib->callsites, node) | |
514 | remove_callsite(callsite); | |
515 | } | |
516 | ||
f99be407 PMF |
517 | /* |
518 | * Update probes, removing the faulty probes. | |
519 | */ | |
520 | static void tracepoint_update_probes(void) | |
521 | { | |
5da10905 MD |
522 | struct tracepoint_lib *lib; |
523 | ||
b27f8e75 | 524 | /* tracepoints registered from libraries and executable. */ |
5da10905 MD |
525 | cds_list_for_each_entry(lib, &libs, list) |
526 | lib_update_tracepoints(lib); | |
f99be407 PMF |
527 | } |
528 | ||
1a206094 | 529 | static struct lttng_ust_tracepoint_probe * |
fbdeb5ec | 530 | tracepoint_add_probe(const char *name, void (*probe)(void), void *data, |
67e5f391 | 531 | const char *signature) |
f99be407 PMF |
532 | { |
533 | struct tracepoint_entry *entry; | |
1a206094 | 534 | struct lttng_ust_tracepoint_probe *old; |
f99be407 PMF |
535 | |
536 | entry = get_tracepoint(name); | |
537 | if (!entry) { | |
67e5f391 | 538 | entry = add_tracepoint(name, signature); |
f99be407 | 539 | if (IS_ERR(entry)) |
1a206094 | 540 | return (struct lttng_ust_tracepoint_probe *)entry; |
f99be407 | 541 | } |
9dec086e | 542 | old = tracepoint_entry_add_probe(entry, probe, data); |
f99be407 PMF |
543 | if (IS_ERR(old) && !entry->refcount) |
544 | remove_tracepoint(entry); | |
545 | return old; | |
546 | } | |
547 | ||
548 | /** | |
81614639 | 549 | * __tracepoint_probe_register - Connect a probe to a tracepoint |
f99be407 PMF |
550 | * @name: tracepoint name |
551 | * @probe: probe handler | |
552 | * | |
553 | * Returns 0 if ok, error value on error. | |
554 | * The probe address must at least be aligned on the architecture pointer size. | |
8792fbae | 555 | * Called with the tracepoint mutex held. |
f99be407 | 556 | */ |
fbdeb5ec MD |
557 | int __tracepoint_probe_register(const char *name, void (*probe)(void), |
558 | void *data, const char *signature) | |
f99be407 PMF |
559 | { |
560 | void *old; | |
8792fbae | 561 | int ret = 0; |
f99be407 | 562 | |
05780d81 MD |
563 | DBG("Registering probe to tracepoint %s", name); |
564 | ||
8792fbae | 565 | pthread_mutex_lock(&tracepoint_mutex); |
67e5f391 | 566 | old = tracepoint_add_probe(name, probe, data, signature); |
8792fbae MD |
567 | if (IS_ERR(old)) { |
568 | ret = PTR_ERR(old); | |
569 | goto end; | |
570 | } | |
f99be407 | 571 | |
3469bbbe | 572 | tracepoint_sync_callsites(name); |
f99be407 | 573 | release_probes(old); |
8792fbae MD |
574 | end: |
575 | pthread_mutex_unlock(&tracepoint_mutex); | |
576 | return ret; | |
f99be407 | 577 | } |
f99be407 | 578 | |
fbdeb5ec MD |
579 | static void *tracepoint_remove_probe(const char *name, void (*probe)(void), |
580 | void *data) | |
f99be407 PMF |
581 | { |
582 | struct tracepoint_entry *entry; | |
583 | void *old; | |
584 | ||
585 | entry = get_tracepoint(name); | |
586 | if (!entry) | |
587 | return ERR_PTR(-ENOENT); | |
9dec086e | 588 | old = tracepoint_entry_remove_probe(entry, probe, data); |
f99be407 PMF |
589 | if (IS_ERR(old)) |
590 | return old; | |
591 | if (!entry->refcount) | |
592 | remove_tracepoint(entry); | |
593 | return old; | |
594 | } | |
595 | ||
596 | /** | |
597 | * tracepoint_probe_unregister - Disconnect a probe from a tracepoint | |
598 | * @name: tracepoint name | |
599 | * @probe: probe function pointer | |
9dec086e | 600 | * @probe: probe data pointer |
f99be407 | 601 | */ |
fbdeb5ec MD |
602 | int __tracepoint_probe_unregister(const char *name, void (*probe)(void), |
603 | void *data) | |
f99be407 PMF |
604 | { |
605 | void *old; | |
8792fbae | 606 | int ret = 0; |
f99be407 | 607 | |
05780d81 MD |
608 | DBG("Un-registering probe from tracepoint %s", name); |
609 | ||
8792fbae | 610 | pthread_mutex_lock(&tracepoint_mutex); |
9dec086e | 611 | old = tracepoint_remove_probe(name, probe, data); |
8792fbae MD |
612 | if (IS_ERR(old)) { |
613 | ret = PTR_ERR(old); | |
614 | goto end; | |
615 | } | |
3469bbbe | 616 | tracepoint_sync_callsites(name); |
f99be407 | 617 | release_probes(old); |
8792fbae MD |
618 | end: |
619 | pthread_mutex_unlock(&tracepoint_mutex); | |
620 | return ret; | |
f99be407 | 621 | } |
f99be407 | 622 | |
f99be407 PMF |
623 | static void tracepoint_add_old_probes(void *old) |
624 | { | |
625 | need_update = 1; | |
626 | if (old) { | |
b728d87e | 627 | struct tp_probes *tp_probes = caa_container_of(old, |
f99be407 | 628 | struct tp_probes, probes[0]); |
0222e121 | 629 | cds_list_add(&tp_probes->u.list, &old_probes); |
f99be407 PMF |
630 | } |
631 | } | |
632 | ||
633 | /** | |
634 | * tracepoint_probe_register_noupdate - register a probe but not connect | |
635 | * @name: tracepoint name | |
636 | * @probe: probe handler | |
637 | * | |
638 | * caller must call tracepoint_probe_update_all() | |
639 | */ | |
fbdeb5ec | 640 | int tracepoint_probe_register_noupdate(const char *name, void (*probe)(void), |
67e5f391 | 641 | void *data, const char *signature) |
f99be407 PMF |
642 | { |
643 | void *old; | |
8792fbae | 644 | int ret = 0; |
f99be407 | 645 | |
8792fbae | 646 | pthread_mutex_lock(&tracepoint_mutex); |
67e5f391 | 647 | old = tracepoint_add_probe(name, probe, data, signature); |
f99be407 | 648 | if (IS_ERR(old)) { |
8792fbae MD |
649 | ret = PTR_ERR(old); |
650 | goto end; | |
f99be407 PMF |
651 | } |
652 | tracepoint_add_old_probes(old); | |
8792fbae MD |
653 | end: |
654 | pthread_mutex_unlock(&tracepoint_mutex); | |
655 | return ret; | |
f99be407 | 656 | } |
f99be407 PMF |
657 | |
658 | /** | |
659 | * tracepoint_probe_unregister_noupdate - remove a probe but not disconnect | |
660 | * @name: tracepoint name | |
661 | * @probe: probe function pointer | |
662 | * | |
663 | * caller must call tracepoint_probe_update_all() | |
8792fbae | 664 | * Called with the tracepoint mutex held. |
f99be407 | 665 | */ |
fbdeb5ec | 666 | int tracepoint_probe_unregister_noupdate(const char *name, void (*probe)(void), |
9dec086e | 667 | void *data) |
f99be407 PMF |
668 | { |
669 | void *old; | |
8792fbae | 670 | int ret = 0; |
f99be407 | 671 | |
05780d81 MD |
672 | DBG("Un-registering probe from tracepoint %s", name); |
673 | ||
8792fbae | 674 | pthread_mutex_lock(&tracepoint_mutex); |
9dec086e | 675 | old = tracepoint_remove_probe(name, probe, data); |
f99be407 | 676 | if (IS_ERR(old)) { |
8792fbae MD |
677 | ret = PTR_ERR(old); |
678 | goto end; | |
f99be407 PMF |
679 | } |
680 | tracepoint_add_old_probes(old); | |
8792fbae MD |
681 | end: |
682 | pthread_mutex_unlock(&tracepoint_mutex); | |
683 | return ret; | |
f99be407 | 684 | } |
f99be407 PMF |
685 | |
686 | /** | |
687 | * tracepoint_probe_update_all - update tracepoints | |
688 | */ | |
689 | void tracepoint_probe_update_all(void) | |
690 | { | |
0222e121 | 691 | CDS_LIST_HEAD(release_probes); |
f99be407 PMF |
692 | struct tp_probes *pos, *next; |
693 | ||
8792fbae | 694 | pthread_mutex_lock(&tracepoint_mutex); |
f99be407 | 695 | if (!need_update) { |
8792fbae | 696 | goto end; |
f99be407 | 697 | } |
0222e121 MD |
698 | if (!cds_list_empty(&old_probes)) |
699 | cds_list_replace_init(&old_probes, &release_probes); | |
f99be407 | 700 | need_update = 0; |
f99be407 PMF |
701 | |
702 | tracepoint_update_probes(); | |
0222e121 MD |
703 | cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) { |
704 | cds_list_del(&pos->u.list); | |
474d745f | 705 | synchronize_rcu(); |
909bc43f | 706 | free(pos); |
f99be407 | 707 | } |
8792fbae MD |
708 | end: |
709 | pthread_mutex_unlock(&tracepoint_mutex); | |
f99be407 | 710 | } |
f99be407 | 711 | |
1a206094 | 712 | void tracepoint_set_new_tracepoint_cb(void (*cb)(struct lttng_ust_tracepoint *)) |
474d745f PMF |
713 | { |
714 | new_tracepoint_cb = cb; | |
715 | } | |
f99be407 | 716 | |
1a206094 SM |
717 | static void new_tracepoints(struct lttng_ust_tracepoint * const *start, |
718 | struct lttng_ust_tracepoint * const *end) | |
f99be407 | 719 | { |
f218ff28 | 720 | if (new_tracepoint_cb) { |
1a206094 | 721 | struct lttng_ust_tracepoint * const *t; |
f08ebbe2 | 722 | |
b27f8e75 | 723 | for (t = start; t < end; t++) { |
f08ebbe2 MD |
724 | if (*t) |
725 | new_tracepoint_cb(*t); | |
474d745f PMF |
726 | } |
727 | } | |
f99be407 | 728 | } |
f99be407 | 729 | |
1a206094 | 730 | int tracepoint_register_lib(struct lttng_ust_tracepoint * const *tracepoints_start, |
b27f8e75 | 731 | int tracepoints_count) |
474d745f | 732 | { |
b467f7a7 | 733 | struct tracepoint_lib *pl, *iter; |
474d745f | 734 | |
edaa1431 MD |
735 | init_tracepoint(); |
736 | ||
1dba3e6c | 737 | pl = (struct tracepoint_lib *) zmalloc(sizeof(struct tracepoint_lib)); |
d6297168 MD |
738 | if (!pl) { |
739 | PERROR("Unable to register tracepoint lib"); | |
740 | return -1; | |
741 | } | |
474d745f PMF |
742 | pl->tracepoints_start = tracepoints_start; |
743 | pl->tracepoints_count = tracepoints_count; | |
3469bbbe | 744 | CDS_INIT_LIST_HEAD(&pl->callsites); |
474d745f | 745 | |
8792fbae | 746 | pthread_mutex_lock(&tracepoint_mutex); |
b467f7a7 MD |
747 | /* |
748 | * We sort the libs by struct lib pointer address. | |
749 | */ | |
750 | cds_list_for_each_entry_reverse(iter, &libs, list) { | |
751 | BUG_ON(iter == pl); /* Should never be in the list twice */ | |
752 | if (iter < pl) { | |
753 | /* We belong to the location right after iter. */ | |
754 | cds_list_add(&pl->list, &iter->list); | |
755 | goto lib_added; | |
756 | } | |
757 | } | |
758 | /* We should be added at the head of the list */ | |
0222e121 | 759 | cds_list_add(&pl->list, &libs); |
b467f7a7 | 760 | lib_added: |
474d745f | 761 | new_tracepoints(tracepoints_start, tracepoints_start + tracepoints_count); |
3469bbbe | 762 | lib_register_callsites(pl); |
5da10905 | 763 | lib_update_tracepoints(pl); |
8792fbae | 764 | pthread_mutex_unlock(&tracepoint_mutex); |
474d745f | 765 | |
1fcf7ad7 MD |
766 | DBG("just registered a tracepoints section from %p and having %d tracepoints", |
767 | tracepoints_start, tracepoints_count); | |
05780d81 MD |
768 | if (ust_debug()) { |
769 | int i; | |
770 | ||
771 | for (i = 0; i < tracepoints_count; i++) { | |
772 | DBG("registered tracepoint: %s", tracepoints_start[i]->name); | |
773 | } | |
774 | } | |
9dec086e | 775 | |
474d745f PMF |
776 | return 0; |
777 | } | |
778 | ||
1a206094 | 779 | int tracepoint_unregister_lib(struct lttng_ust_tracepoint * const *tracepoints_start) |
474d745f | 780 | { |
24b6668c PMF |
781 | struct tracepoint_lib *lib; |
782 | ||
8792fbae | 783 | pthread_mutex_lock(&tracepoint_mutex); |
0222e121 | 784 | cds_list_for_each_entry(lib, &libs, list) { |
3469bbbe MD |
785 | if (lib->tracepoints_start != tracepoints_start) |
786 | continue; | |
1622ba22 | 787 | |
3469bbbe MD |
788 | cds_list_del(&lib->list); |
789 | /* | |
8a7ad54b IJ |
790 | * Unregistering a callsite also decreases the |
791 | * callsite reference count of the corresponding | |
792 | * tracepoint, and disables the tracepoint if | |
793 | * the reference count drops to zero. | |
3469bbbe | 794 | */ |
3469bbbe MD |
795 | lib_unregister_callsites(lib); |
796 | DBG("just unregistered a tracepoints section from %p", | |
797 | lib->tracepoints_start); | |
798 | free(lib); | |
799 | break; | |
24b6668c | 800 | } |
8792fbae | 801 | pthread_mutex_unlock(&tracepoint_mutex); |
474d745f PMF |
802 | return 0; |
803 | } | |
b27f8e75 | 804 | |
edaa1431 | 805 | void init_tracepoint(void) |
b27f8e75 | 806 | { |
edaa1431 MD |
807 | if (uatomic_xchg(&initialized, 1) == 1) |
808 | return; | |
5e96a467 | 809 | init_usterr(); |
b27f8e75 MD |
810 | } |
811 | ||
edaa1431 | 812 | void exit_tracepoint(void) |
b27f8e75 | 813 | { |
17dfb34b | 814 | initialized = 0; |
b27f8e75 | 815 | } |
40b2b5a4 MD |
816 | |
817 | /* | |
818 | * Create the wrapper symbols. | |
819 | */ | |
820 | #undef tp_rcu_read_lock_bp | |
821 | #undef tp_rcu_read_unlock_bp | |
822 | #undef tp_rcu_dereference_bp | |
823 | ||
824 | void tp_rcu_read_lock_bp(void) | |
825 | { | |
826 | rcu_read_lock_bp(); | |
827 | } | |
828 | ||
829 | void tp_rcu_read_unlock_bp(void) | |
830 | { | |
831 | rcu_read_unlock_bp(); | |
832 | } | |
833 | ||
834 | void *tp_rcu_dereference_sym_bp(void *p) | |
835 | { | |
836 | return rcu_dereference_bp(p); | |
837 | } |