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 MD |
47 | static int initialized; |
48 | static void (*new_tracepoint_cb)(struct 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; |
b979b346 | 96 | struct tracepoint_probe *probes; |
f99be407 | 97 | int refcount; /* Number of times armed. 0 if disarmed. */ |
67e5f391 | 98 | const char *signature; |
f99be407 PMF |
99 | char name[0]; |
100 | }; | |
101 | ||
102 | struct tp_probes { | |
103 | union { | |
0222e121 | 104 | struct cds_list_head list; |
ade7037b MD |
105 | /* Field below only used for call_rcu scheme */ |
106 | /* struct rcu_head head; */ | |
f99be407 | 107 | } u; |
b979b346 | 108 | struct tracepoint_probe probes[0]; |
f99be407 PMF |
109 | }; |
110 | ||
3469bbbe MD |
111 | /* |
112 | * Callsite hash table, containing the tracepoint call sites. | |
113 | * Protected by tracepoint mutex. | |
114 | */ | |
115 | #define CALLSITE_HASH_BITS 12 | |
116 | #define CALLSITE_TABLE_SIZE (1 << CALLSITE_HASH_BITS) | |
117 | static struct cds_hlist_head callsite_table[CALLSITE_TABLE_SIZE]; | |
118 | ||
119 | struct callsite_entry { | |
120 | struct cds_hlist_node hlist; /* hash table node */ | |
121 | struct cds_list_head node; /* lib list of callsites node */ | |
122 | struct tracepoint *tp; | |
123 | }; | |
124 | ||
efa2c591 | 125 | static void *allocate_probes(int count) |
f99be407 | 126 | { |
b979b346 | 127 | struct tp_probes *p = zmalloc(count * sizeof(struct tracepoint_probe) |
909bc43f | 128 | + sizeof(struct tp_probes)); |
f99be407 PMF |
129 | return p == NULL ? NULL : p->probes; |
130 | } | |
131 | ||
efa2c591 | 132 | static void release_probes(void *old) |
f99be407 PMF |
133 | { |
134 | if (old) { | |
b728d87e | 135 | struct tp_probes *tp_probes = caa_container_of(old, |
f99be407 | 136 | struct tp_probes, probes[0]); |
474d745f | 137 | synchronize_rcu(); |
909bc43f | 138 | free(tp_probes); |
f99be407 PMF |
139 | } |
140 | } | |
141 | ||
142 | static void debug_print_probes(struct tracepoint_entry *entry) | |
143 | { | |
144 | int i; | |
145 | ||
9dec086e | 146 | if (!tracepoint_debug || !entry->probes) |
f99be407 PMF |
147 | return; |
148 | ||
9dec086e NC |
149 | for (i = 0; entry->probes[i].func; i++) |
150 | DBG("Probe %d : %p", i, entry->probes[i].func); | |
f99be407 PMF |
151 | } |
152 | ||
153 | static void * | |
9dec086e | 154 | tracepoint_entry_add_probe(struct tracepoint_entry *entry, |
fbdeb5ec | 155 | void (*probe)(void), void *data) |
f99be407 PMF |
156 | { |
157 | int nr_probes = 0; | |
b979b346 | 158 | struct tracepoint_probe *old, *new; |
f99be407 | 159 | |
d7509147 MD |
160 | if (!probe) { |
161 | WARN_ON(1); | |
162 | return ERR_PTR(-EINVAL); | |
163 | } | |
f99be407 | 164 | debug_print_probes(entry); |
9dec086e | 165 | old = entry->probes; |
f99be407 PMF |
166 | if (old) { |
167 | /* (N -> N+1), (N != 0, 1) probes */ | |
9dec086e NC |
168 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) |
169 | if (old[nr_probes].func == probe && | |
170 | old[nr_probes].data == data) | |
f99be407 PMF |
171 | return ERR_PTR(-EEXIST); |
172 | } | |
173 | /* + 2 : one for new probe, one for NULL func */ | |
174 | new = allocate_probes(nr_probes + 2); | |
175 | if (new == NULL) | |
176 | return ERR_PTR(-ENOMEM); | |
177 | if (old) | |
b979b346 | 178 | memcpy(new, old, nr_probes * sizeof(struct tracepoint_probe)); |
9dec086e NC |
179 | new[nr_probes].func = probe; |
180 | new[nr_probes].data = data; | |
181 | new[nr_probes + 1].func = NULL; | |
f99be407 | 182 | entry->refcount = nr_probes + 1; |
9dec086e | 183 | entry->probes = new; |
f99be407 PMF |
184 | debug_print_probes(entry); |
185 | return old; | |
186 | } | |
187 | ||
188 | static void * | |
fbdeb5ec MD |
189 | tracepoint_entry_remove_probe(struct tracepoint_entry *entry, |
190 | void (*probe)(void), void *data) | |
f99be407 PMF |
191 | { |
192 | int nr_probes = 0, nr_del = 0, i; | |
b979b346 | 193 | struct tracepoint_probe *old, *new; |
f99be407 | 194 | |
9dec086e | 195 | old = entry->probes; |
f99be407 PMF |
196 | |
197 | if (!old) | |
198 | return ERR_PTR(-ENOENT); | |
199 | ||
200 | debug_print_probes(entry); | |
201 | /* (N -> M), (N > 1, M >= 0) probes */ | |
956c6fab MD |
202 | if (probe) { |
203 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) { | |
204 | if (old[nr_probes].func == probe && | |
205 | old[nr_probes].data == data) | |
206 | nr_del++; | |
207 | } | |
f99be407 PMF |
208 | } |
209 | ||
210 | if (nr_probes - nr_del == 0) { | |
211 | /* N -> 0, (N > 1) */ | |
9dec086e | 212 | entry->probes = NULL; |
f99be407 PMF |
213 | entry->refcount = 0; |
214 | debug_print_probes(entry); | |
215 | return old; | |
216 | } else { | |
217 | int j = 0; | |
218 | /* N -> M, (N > 1, M > 0) */ | |
219 | /* + 1 for NULL */ | |
220 | new = allocate_probes(nr_probes - nr_del + 1); | |
221 | if (new == NULL) | |
222 | return ERR_PTR(-ENOMEM); | |
9dec086e | 223 | for (i = 0; old[i].func; i++) |
956c6fab | 224 | if (old[i].func != probe || old[i].data != data) |
f99be407 | 225 | new[j++] = old[i]; |
9dec086e | 226 | new[nr_probes - nr_del].func = NULL; |
f99be407 | 227 | entry->refcount = nr_probes - nr_del; |
9dec086e | 228 | entry->probes = new; |
f99be407 PMF |
229 | } |
230 | debug_print_probes(entry); | |
231 | return old; | |
232 | } | |
233 | ||
234 | /* | |
235 | * Get tracepoint if the tracepoint is present in the tracepoint hash table. | |
8792fbae | 236 | * Must be called with tracepoint mutex held. |
f99be407 PMF |
237 | * Returns NULL if not present. |
238 | */ | |
239 | static struct tracepoint_entry *get_tracepoint(const char *name) | |
240 | { | |
10c56168 DG |
241 | struct cds_hlist_head *head; |
242 | struct cds_hlist_node *node; | |
f99be407 | 243 | struct tracepoint_entry *e; |
ff412fb5 MD |
244 | size_t name_len = strlen(name); |
245 | uint32_t hash; | |
f99be407 | 246 | |
ff412fb5 MD |
247 | if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { |
248 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); | |
249 | name_len = LTTNG_UST_SYM_NAME_LEN - 1; | |
250 | } | |
251 | hash = jhash(name, name_len, 0); | |
f99be407 | 252 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
10c56168 | 253 | cds_hlist_for_each_entry(e, node, head, hlist) { |
ff412fb5 | 254 | if (!strncmp(name, e->name, LTTNG_UST_SYM_NAME_LEN - 1)) |
f99be407 PMF |
255 | return e; |
256 | } | |
257 | return NULL; | |
258 | } | |
259 | ||
260 | /* | |
261 | * Add the tracepoint to the tracepoint hash table. Must be called with | |
8792fbae | 262 | * tracepoint mutex held. |
f99be407 | 263 | */ |
67e5f391 MD |
264 | static struct tracepoint_entry *add_tracepoint(const char *name, |
265 | const char *signature) | |
f99be407 | 266 | { |
10c56168 DG |
267 | struct cds_hlist_head *head; |
268 | struct cds_hlist_node *node; | |
f99be407 | 269 | struct tracepoint_entry *e; |
ff412fb5 MD |
270 | size_t name_len = strlen(name); |
271 | uint32_t hash; | |
f99be407 | 272 | |
ff412fb5 MD |
273 | if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { |
274 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); | |
275 | name_len = LTTNG_UST_SYM_NAME_LEN - 1; | |
276 | } | |
277 | hash = jhash(name, name_len, 0); | |
f99be407 | 278 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
10c56168 | 279 | cds_hlist_for_each_entry(e, node, head, hlist) { |
ff412fb5 | 280 | if (!strncmp(name, e->name, LTTNG_UST_SYM_NAME_LEN - 1)) { |
c1f20530 | 281 | DBG("tracepoint %s busy", name); |
f99be407 PMF |
282 | return ERR_PTR(-EEXIST); /* Already there */ |
283 | } | |
284 | } | |
285 | /* | |
1dba3e6c | 286 | * Using zmalloc here to allocate a variable length element. Could |
f99be407 PMF |
287 | * cause some memory fragmentation if overused. |
288 | */ | |
ff412fb5 | 289 | e = zmalloc(sizeof(struct tracepoint_entry) + name_len + 1); |
f99be407 PMF |
290 | if (!e) |
291 | return ERR_PTR(-ENOMEM); | |
ff412fb5 MD |
292 | memcpy(&e->name[0], name, name_len + 1); |
293 | e->name[name_len] = '\0'; | |
9dec086e | 294 | e->probes = NULL; |
f99be407 | 295 | e->refcount = 0; |
67e5f391 | 296 | e->signature = signature; |
10c56168 | 297 | cds_hlist_add_head(&e->hlist, head); |
f99be407 PMF |
298 | return e; |
299 | } | |
300 | ||
301 | /* | |
302 | * Remove the tracepoint from the tracepoint hash table. Must be called with | |
8792fbae | 303 | * tracepoint mutex held. |
f99be407 | 304 | */ |
efa2c591 | 305 | static void remove_tracepoint(struct tracepoint_entry *e) |
f99be407 | 306 | { |
10c56168 | 307 | cds_hlist_del(&e->hlist); |
909bc43f | 308 | free(e); |
f99be407 PMF |
309 | } |
310 | ||
3469bbbe MD |
311 | /* |
312 | * Add the callsite to the callsite hash table. Must be called with | |
313 | * tracepoint mutex held. | |
314 | */ | |
315 | static void add_callsite(struct tracepoint *tp) | |
316 | { | |
317 | struct cds_hlist_head *head; | |
318 | struct callsite_entry *e; | |
319 | const char *name = tp->name; | |
320 | size_t name_len = strlen(name); | |
321 | uint32_t hash; | |
322 | ||
323 | if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { | |
324 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); | |
325 | name_len = LTTNG_UST_SYM_NAME_LEN - 1; | |
326 | } | |
327 | hash = jhash(name, name_len, 0); | |
328 | head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)]; | |
329 | e = zmalloc(sizeof(struct callsite_entry)); | |
330 | assert(e); | |
331 | cds_hlist_add_head(&e->hlist, head); | |
332 | e->tp = tp; | |
333 | } | |
334 | ||
335 | /* | |
336 | * Remove the callsite from the callsite hash table and from lib | |
337 | * callsite list. Must be called with tracepoint mutex held. | |
338 | */ | |
339 | static void remove_callsite(struct callsite_entry *e) | |
340 | { | |
341 | cds_hlist_del(&e->hlist); | |
342 | cds_list_del(&e->node); | |
343 | free(e); | |
344 | } | |
345 | ||
f99be407 PMF |
346 | /* |
347 | * Sets the probe callback corresponding to one tracepoint. | |
348 | */ | |
349 | static void set_tracepoint(struct tracepoint_entry **entry, | |
350 | struct tracepoint *elem, int active) | |
351 | { | |
ff412fb5 | 352 | WARN_ON(strncmp((*entry)->name, elem->name, LTTNG_UST_SYM_NAME_LEN - 1) != 0); |
67e5f391 MD |
353 | /* |
354 | * Check that signatures match before connecting a probe to a | |
355 | * tracepoint. Warn the user if they don't. | |
356 | */ | |
357 | if (strcmp(elem->signature, (*entry)->signature) != 0) { | |
358 | static int warned = 0; | |
359 | ||
360 | /* Only print once, don't flood console. */ | |
361 | if (!warned) { | |
362 | WARN("Tracepoint signature mismatch, not enabling one or more tracepoints. Ensure that the tracepoint probes prototypes match the application."); | |
363 | WARN("Tracepoint \"%s\" signatures: call: \"%s\" vs probe: \"%s\".", | |
364 | elem->name, elem->signature, (*entry)->signature); | |
365 | warned = 1; | |
366 | } | |
367 | /* Don't accept connecting non-matching signatures. */ | |
368 | return; | |
369 | } | |
f99be407 PMF |
370 | |
371 | /* | |
0222e121 | 372 | * rcu_assign_pointer has a cmm_smp_wmb() which makes sure that the new |
f99be407 PMF |
373 | * probe callbacks array is consistent before setting a pointer to it. |
374 | * This array is referenced by __DO_TRACE from | |
0222e121 | 375 | * include/linux/tracepoints.h. A matching cmm_smp_read_barrier_depends() |
f99be407 PMF |
376 | * is used. |
377 | */ | |
9dec086e | 378 | rcu_assign_pointer(elem->probes, (*entry)->probes); |
f36c12ab | 379 | elem->state = active; |
f99be407 PMF |
380 | } |
381 | ||
382 | /* | |
383 | * Disable a tracepoint and its probe callback. | |
384 | * Note: only waiting an RCU period after setting elem->call to the empty | |
385 | * function insures that the original callback is not used anymore. This insured | |
386 | * by preempt_disable around the call site. | |
387 | */ | |
388 | static void disable_tracepoint(struct tracepoint *elem) | |
389 | { | |
f36c12ab | 390 | elem->state = 0; |
9dec086e | 391 | rcu_assign_pointer(elem->probes, NULL); |
f99be407 PMF |
392 | } |
393 | ||
3469bbbe MD |
394 | /* |
395 | * Enable/disable all callsites based on the state of a specific | |
396 | * tracepoint entry. | |
397 | * Must be called with tracepoint mutex held. | |
398 | */ | |
399 | static void tracepoint_sync_callsites(const char *name) | |
400 | { | |
401 | struct cds_hlist_head *head; | |
402 | struct cds_hlist_node *node; | |
403 | struct callsite_entry *e; | |
404 | size_t name_len = strlen(name); | |
405 | uint32_t hash; | |
406 | struct tracepoint_entry *tp_entry; | |
407 | ||
408 | tp_entry = get_tracepoint(name); | |
409 | if (name_len > LTTNG_UST_SYM_NAME_LEN - 1) { | |
410 | WARN("Truncating tracepoint name %s which exceeds size limits of %u chars", name, LTTNG_UST_SYM_NAME_LEN - 1); | |
411 | name_len = LTTNG_UST_SYM_NAME_LEN - 1; | |
412 | } | |
413 | hash = jhash(name, name_len, 0); | |
414 | head = &callsite_table[hash & (CALLSITE_TABLE_SIZE - 1)]; | |
415 | cds_hlist_for_each_entry(e, node, head, hlist) { | |
416 | struct tracepoint *tp = e->tp; | |
417 | ||
418 | if (strncmp(name, tp->name, LTTNG_UST_SYM_NAME_LEN - 1)) | |
419 | continue; | |
420 | if (tp_entry) { | |
421 | set_tracepoint(&tp_entry, tp, | |
422 | !!tp_entry->refcount); | |
423 | } else { | |
424 | disable_tracepoint(tp); | |
425 | } | |
426 | } | |
427 | } | |
428 | ||
f99be407 PMF |
429 | /** |
430 | * tracepoint_update_probe_range - Update a probe range | |
431 | * @begin: beginning of the range | |
432 | * @end: end of the range | |
433 | * | |
434 | * Updates the probe callback corresponding to a range of tracepoints. | |
435 | */ | |
b27f8e75 | 436 | static |
f218ff28 MD |
437 | void tracepoint_update_probe_range(struct tracepoint * const *begin, |
438 | struct tracepoint * const *end) | |
f99be407 | 439 | { |
f218ff28 | 440 | struct tracepoint * const *iter; |
f99be407 PMF |
441 | struct tracepoint_entry *mark_entry; |
442 | ||
f99be407 | 443 | for (iter = begin; iter < end; iter++) { |
f08ebbe2 MD |
444 | if (!*iter) |
445 | continue; /* skip dummy */ | |
f218ff28 MD |
446 | if (!(*iter)->name) { |
447 | disable_tracepoint(*iter); | |
9dec086e NC |
448 | continue; |
449 | } | |
f218ff28 | 450 | mark_entry = get_tracepoint((*iter)->name); |
f99be407 | 451 | if (mark_entry) { |
f218ff28 | 452 | set_tracepoint(&mark_entry, *iter, |
f99be407 PMF |
453 | !!mark_entry->refcount); |
454 | } else { | |
f218ff28 | 455 | disable_tracepoint(*iter); |
f99be407 PMF |
456 | } |
457 | } | |
f99be407 PMF |
458 | } |
459 | ||
5da10905 | 460 | static void lib_update_tracepoints(struct tracepoint_lib *lib) |
772030fe | 461 | { |
5da10905 MD |
462 | tracepoint_update_probe_range(lib->tracepoints_start, |
463 | lib->tracepoints_start + lib->tracepoints_count); | |
772030fe PMF |
464 | } |
465 | ||
3469bbbe MD |
466 | static void lib_register_callsites(struct tracepoint_lib *lib) |
467 | { | |
468 | struct tracepoint * const *begin; | |
469 | struct tracepoint * const *end; | |
470 | struct tracepoint * const *iter; | |
471 | ||
472 | begin = lib->tracepoints_start; | |
473 | end = lib->tracepoints_start + lib->tracepoints_count; | |
474 | ||
475 | for (iter = begin; iter < end; iter++) { | |
476 | if (!*iter) | |
477 | continue; /* skip dummy */ | |
478 | if (!(*iter)->name) { | |
479 | continue; | |
480 | } | |
481 | add_callsite(*iter); | |
482 | } | |
483 | } | |
484 | ||
485 | static void lib_unregister_callsites(struct tracepoint_lib *lib) | |
486 | { | |
487 | struct callsite_entry *callsite, *tmp; | |
488 | ||
489 | cds_list_for_each_entry_safe(callsite, tmp, &lib->callsites, node) | |
490 | remove_callsite(callsite); | |
491 | } | |
492 | ||
f99be407 PMF |
493 | /* |
494 | * Update probes, removing the faulty probes. | |
495 | */ | |
496 | static void tracepoint_update_probes(void) | |
497 | { | |
5da10905 MD |
498 | struct tracepoint_lib *lib; |
499 | ||
b27f8e75 | 500 | /* tracepoints registered from libraries and executable. */ |
5da10905 MD |
501 | cds_list_for_each_entry(lib, &libs, list) |
502 | lib_update_tracepoints(lib); | |
f99be407 PMF |
503 | } |
504 | ||
b979b346 | 505 | static struct tracepoint_probe * |
fbdeb5ec | 506 | tracepoint_add_probe(const char *name, void (*probe)(void), void *data, |
67e5f391 | 507 | const char *signature) |
f99be407 PMF |
508 | { |
509 | struct tracepoint_entry *entry; | |
b979b346 | 510 | struct tracepoint_probe *old; |
f99be407 PMF |
511 | |
512 | entry = get_tracepoint(name); | |
513 | if (!entry) { | |
67e5f391 | 514 | entry = add_tracepoint(name, signature); |
f99be407 | 515 | if (IS_ERR(entry)) |
b979b346 | 516 | return (struct tracepoint_probe *)entry; |
f99be407 | 517 | } |
9dec086e | 518 | old = tracepoint_entry_add_probe(entry, probe, data); |
f99be407 PMF |
519 | if (IS_ERR(old) && !entry->refcount) |
520 | remove_tracepoint(entry); | |
521 | return old; | |
522 | } | |
523 | ||
524 | /** | |
81614639 | 525 | * __tracepoint_probe_register - Connect a probe to a tracepoint |
f99be407 PMF |
526 | * @name: tracepoint name |
527 | * @probe: probe handler | |
528 | * | |
529 | * Returns 0 if ok, error value on error. | |
530 | * The probe address must at least be aligned on the architecture pointer size. | |
8792fbae | 531 | * Called with the tracepoint mutex held. |
f99be407 | 532 | */ |
fbdeb5ec MD |
533 | int __tracepoint_probe_register(const char *name, void (*probe)(void), |
534 | void *data, const char *signature) | |
f99be407 PMF |
535 | { |
536 | void *old; | |
8792fbae | 537 | int ret = 0; |
f99be407 | 538 | |
05780d81 MD |
539 | DBG("Registering probe to tracepoint %s", name); |
540 | ||
8792fbae | 541 | pthread_mutex_lock(&tracepoint_mutex); |
67e5f391 | 542 | old = tracepoint_add_probe(name, probe, data, signature); |
8792fbae MD |
543 | if (IS_ERR(old)) { |
544 | ret = PTR_ERR(old); | |
545 | goto end; | |
546 | } | |
f99be407 | 547 | |
3469bbbe | 548 | tracepoint_sync_callsites(name); |
f99be407 | 549 | release_probes(old); |
8792fbae MD |
550 | end: |
551 | pthread_mutex_unlock(&tracepoint_mutex); | |
552 | return ret; | |
f99be407 | 553 | } |
f99be407 | 554 | |
fbdeb5ec MD |
555 | static void *tracepoint_remove_probe(const char *name, void (*probe)(void), |
556 | void *data) | |
f99be407 PMF |
557 | { |
558 | struct tracepoint_entry *entry; | |
559 | void *old; | |
560 | ||
561 | entry = get_tracepoint(name); | |
562 | if (!entry) | |
563 | return ERR_PTR(-ENOENT); | |
9dec086e | 564 | old = tracepoint_entry_remove_probe(entry, probe, data); |
f99be407 PMF |
565 | if (IS_ERR(old)) |
566 | return old; | |
567 | if (!entry->refcount) | |
568 | remove_tracepoint(entry); | |
569 | return old; | |
570 | } | |
571 | ||
572 | /** | |
573 | * tracepoint_probe_unregister - Disconnect a probe from a tracepoint | |
574 | * @name: tracepoint name | |
575 | * @probe: probe function pointer | |
9dec086e | 576 | * @probe: probe data pointer |
f99be407 | 577 | */ |
fbdeb5ec MD |
578 | int __tracepoint_probe_unregister(const char *name, void (*probe)(void), |
579 | void *data) | |
f99be407 PMF |
580 | { |
581 | void *old; | |
8792fbae | 582 | int ret = 0; |
f99be407 | 583 | |
05780d81 MD |
584 | DBG("Un-registering probe from tracepoint %s", name); |
585 | ||
8792fbae | 586 | pthread_mutex_lock(&tracepoint_mutex); |
9dec086e | 587 | old = tracepoint_remove_probe(name, probe, data); |
8792fbae MD |
588 | if (IS_ERR(old)) { |
589 | ret = PTR_ERR(old); | |
590 | goto end; | |
591 | } | |
3469bbbe | 592 | tracepoint_sync_callsites(name); |
f99be407 | 593 | release_probes(old); |
8792fbae MD |
594 | end: |
595 | pthread_mutex_unlock(&tracepoint_mutex); | |
596 | return ret; | |
f99be407 | 597 | } |
f99be407 | 598 | |
f99be407 PMF |
599 | static void tracepoint_add_old_probes(void *old) |
600 | { | |
601 | need_update = 1; | |
602 | if (old) { | |
b728d87e | 603 | struct tp_probes *tp_probes = caa_container_of(old, |
f99be407 | 604 | struct tp_probes, probes[0]); |
0222e121 | 605 | cds_list_add(&tp_probes->u.list, &old_probes); |
f99be407 PMF |
606 | } |
607 | } | |
608 | ||
609 | /** | |
610 | * tracepoint_probe_register_noupdate - register a probe but not connect | |
611 | * @name: tracepoint name | |
612 | * @probe: probe handler | |
613 | * | |
614 | * caller must call tracepoint_probe_update_all() | |
615 | */ | |
fbdeb5ec | 616 | int tracepoint_probe_register_noupdate(const char *name, void (*probe)(void), |
67e5f391 | 617 | void *data, const char *signature) |
f99be407 PMF |
618 | { |
619 | void *old; | |
8792fbae | 620 | int ret = 0; |
f99be407 | 621 | |
8792fbae | 622 | pthread_mutex_lock(&tracepoint_mutex); |
67e5f391 | 623 | old = tracepoint_add_probe(name, probe, data, signature); |
f99be407 | 624 | if (IS_ERR(old)) { |
8792fbae MD |
625 | ret = PTR_ERR(old); |
626 | goto end; | |
f99be407 PMF |
627 | } |
628 | tracepoint_add_old_probes(old); | |
8792fbae MD |
629 | end: |
630 | pthread_mutex_unlock(&tracepoint_mutex); | |
631 | return ret; | |
f99be407 | 632 | } |
f99be407 PMF |
633 | |
634 | /** | |
635 | * tracepoint_probe_unregister_noupdate - remove a probe but not disconnect | |
636 | * @name: tracepoint name | |
637 | * @probe: probe function pointer | |
638 | * | |
639 | * caller must call tracepoint_probe_update_all() | |
8792fbae | 640 | * Called with the tracepoint mutex held. |
f99be407 | 641 | */ |
fbdeb5ec | 642 | int tracepoint_probe_unregister_noupdate(const char *name, void (*probe)(void), |
9dec086e | 643 | void *data) |
f99be407 PMF |
644 | { |
645 | void *old; | |
8792fbae | 646 | int ret = 0; |
f99be407 | 647 | |
05780d81 MD |
648 | DBG("Un-registering probe from tracepoint %s", name); |
649 | ||
8792fbae | 650 | pthread_mutex_lock(&tracepoint_mutex); |
9dec086e | 651 | old = tracepoint_remove_probe(name, probe, data); |
f99be407 | 652 | if (IS_ERR(old)) { |
8792fbae MD |
653 | ret = PTR_ERR(old); |
654 | goto end; | |
f99be407 PMF |
655 | } |
656 | tracepoint_add_old_probes(old); | |
8792fbae MD |
657 | end: |
658 | pthread_mutex_unlock(&tracepoint_mutex); | |
659 | return ret; | |
f99be407 | 660 | } |
f99be407 PMF |
661 | |
662 | /** | |
663 | * tracepoint_probe_update_all - update tracepoints | |
664 | */ | |
665 | void tracepoint_probe_update_all(void) | |
666 | { | |
0222e121 | 667 | CDS_LIST_HEAD(release_probes); |
f99be407 PMF |
668 | struct tp_probes *pos, *next; |
669 | ||
8792fbae | 670 | pthread_mutex_lock(&tracepoint_mutex); |
f99be407 | 671 | if (!need_update) { |
8792fbae | 672 | goto end; |
f99be407 | 673 | } |
0222e121 MD |
674 | if (!cds_list_empty(&old_probes)) |
675 | cds_list_replace_init(&old_probes, &release_probes); | |
f99be407 | 676 | need_update = 0; |
f99be407 PMF |
677 | |
678 | tracepoint_update_probes(); | |
0222e121 MD |
679 | cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) { |
680 | cds_list_del(&pos->u.list); | |
474d745f | 681 | synchronize_rcu(); |
909bc43f | 682 | free(pos); |
f99be407 | 683 | } |
8792fbae MD |
684 | end: |
685 | pthread_mutex_unlock(&tracepoint_mutex); | |
f99be407 | 686 | } |
f99be407 | 687 | |
474d745f PMF |
688 | void tracepoint_set_new_tracepoint_cb(void (*cb)(struct tracepoint *)) |
689 | { | |
690 | new_tracepoint_cb = cb; | |
691 | } | |
f99be407 | 692 | |
f218ff28 | 693 | static void new_tracepoints(struct tracepoint * const *start, struct tracepoint * const *end) |
f99be407 | 694 | { |
f218ff28 MD |
695 | if (new_tracepoint_cb) { |
696 | struct tracepoint * const *t; | |
f08ebbe2 | 697 | |
b27f8e75 | 698 | for (t = start; t < end; t++) { |
f08ebbe2 MD |
699 | if (*t) |
700 | new_tracepoint_cb(*t); | |
474d745f PMF |
701 | } |
702 | } | |
f99be407 | 703 | } |
f99be407 | 704 | |
1622ba22 | 705 | static |
3469bbbe | 706 | void lib_disable_tracepoints(struct tracepoint_lib *lib) |
1622ba22 | 707 | { |
3469bbbe MD |
708 | struct tracepoint * const *begin; |
709 | struct tracepoint * const *end; | |
1622ba22 MD |
710 | struct tracepoint * const *iter; |
711 | ||
3469bbbe MD |
712 | begin = lib->tracepoints_start; |
713 | end = lib->tracepoints_start + lib->tracepoints_count; | |
714 | ||
1622ba22 MD |
715 | for (iter = begin; iter < end; iter++) { |
716 | if (!*iter) | |
717 | continue; /* skip dummy */ | |
718 | disable_tracepoint(*iter); | |
719 | } | |
720 | ||
721 | } | |
722 | ||
b27f8e75 MD |
723 | int tracepoint_register_lib(struct tracepoint * const *tracepoints_start, |
724 | int tracepoints_count) | |
474d745f | 725 | { |
b467f7a7 | 726 | struct tracepoint_lib *pl, *iter; |
474d745f | 727 | |
edaa1431 MD |
728 | init_tracepoint(); |
729 | ||
1dba3e6c | 730 | pl = (struct tracepoint_lib *) zmalloc(sizeof(struct tracepoint_lib)); |
474d745f PMF |
731 | |
732 | pl->tracepoints_start = tracepoints_start; | |
733 | pl->tracepoints_count = tracepoints_count; | |
3469bbbe | 734 | CDS_INIT_LIST_HEAD(&pl->callsites); |
474d745f | 735 | |
8792fbae | 736 | pthread_mutex_lock(&tracepoint_mutex); |
b467f7a7 MD |
737 | /* |
738 | * We sort the libs by struct lib pointer address. | |
739 | */ | |
740 | cds_list_for_each_entry_reverse(iter, &libs, list) { | |
741 | BUG_ON(iter == pl); /* Should never be in the list twice */ | |
742 | if (iter < pl) { | |
743 | /* We belong to the location right after iter. */ | |
744 | cds_list_add(&pl->list, &iter->list); | |
745 | goto lib_added; | |
746 | } | |
747 | } | |
748 | /* We should be added at the head of the list */ | |
0222e121 | 749 | cds_list_add(&pl->list, &libs); |
b467f7a7 | 750 | lib_added: |
474d745f | 751 | new_tracepoints(tracepoints_start, tracepoints_start + tracepoints_count); |
3469bbbe | 752 | lib_register_callsites(pl); |
5da10905 | 753 | lib_update_tracepoints(pl); |
8792fbae | 754 | pthread_mutex_unlock(&tracepoint_mutex); |
474d745f | 755 | |
1fcf7ad7 MD |
756 | DBG("just registered a tracepoints section from %p and having %d tracepoints", |
757 | tracepoints_start, tracepoints_count); | |
05780d81 MD |
758 | if (ust_debug()) { |
759 | int i; | |
760 | ||
761 | for (i = 0; i < tracepoints_count; i++) { | |
762 | DBG("registered tracepoint: %s", tracepoints_start[i]->name); | |
763 | } | |
764 | } | |
9dec086e | 765 | |
474d745f PMF |
766 | return 0; |
767 | } | |
768 | ||
f218ff28 | 769 | int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start) |
474d745f | 770 | { |
24b6668c PMF |
771 | struct tracepoint_lib *lib; |
772 | ||
8792fbae | 773 | pthread_mutex_lock(&tracepoint_mutex); |
0222e121 | 774 | cds_list_for_each_entry(lib, &libs, list) { |
3469bbbe MD |
775 | if (lib->tracepoints_start != tracepoints_start) |
776 | continue; | |
1622ba22 | 777 | |
3469bbbe MD |
778 | cds_list_del(&lib->list); |
779 | /* | |
780 | * Force tracepoint disarm for all tracepoints of this lib. | |
781 | * This takes care of destructor of library that would leave a | |
782 | * LD_PRELOAD wrapper override function enabled for tracing, but | |
783 | * the session teardown would not be able to reach the | |
784 | * tracepoint anymore to disable it. | |
785 | */ | |
786 | lib_disable_tracepoints(lib); | |
787 | lib_unregister_callsites(lib); | |
788 | DBG("just unregistered a tracepoints section from %p", | |
789 | lib->tracepoints_start); | |
790 | free(lib); | |
791 | break; | |
24b6668c | 792 | } |
8792fbae | 793 | pthread_mutex_unlock(&tracepoint_mutex); |
474d745f PMF |
794 | return 0; |
795 | } | |
b27f8e75 | 796 | |
edaa1431 | 797 | void init_tracepoint(void) |
b27f8e75 | 798 | { |
edaa1431 MD |
799 | if (uatomic_xchg(&initialized, 1) == 1) |
800 | return; | |
5e96a467 | 801 | init_usterr(); |
b27f8e75 MD |
802 | } |
803 | ||
edaa1431 | 804 | void exit_tracepoint(void) |
b27f8e75 | 805 | { |
17dfb34b | 806 | initialized = 0; |
b27f8e75 | 807 | } |
40b2b5a4 MD |
808 | |
809 | /* | |
810 | * Create the wrapper symbols. | |
811 | */ | |
812 | #undef tp_rcu_read_lock_bp | |
813 | #undef tp_rcu_read_unlock_bp | |
814 | #undef tp_rcu_dereference_bp | |
815 | ||
816 | void tp_rcu_read_lock_bp(void) | |
817 | { | |
818 | rcu_read_lock_bp(); | |
819 | } | |
820 | ||
821 | void tp_rcu_read_unlock_bp(void) | |
822 | { | |
823 | rcu_read_unlock_bp(); | |
824 | } | |
825 | ||
826 | void *tp_rcu_dereference_sym_bp(void *p) | |
827 | { | |
828 | return rcu_dereference_bp(p); | |
829 | } |