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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> | |
44c72f10 | 26 | |
b728d87e | 27 | #include <urcu/arch.h> |
b7ea1a1c | 28 | #include <urcu-bp.h> |
10c56168 | 29 | #include <urcu/hlist.h> |
edaa1431 | 30 | #include <urcu/uatomic.h> |
b728d87e | 31 | #include <urcu/compiler.h> |
44c72f10 MD |
32 | |
33 | #include <lttng/tracepoint.h> | |
34 | ||
35 | #include <usterr-signal-safe.h> | |
35897f8b | 36 | #include <helper.h> |
474d745f | 37 | |
23c8854a | 38 | #include "tracepoint-internal.h" |
b751f722 | 39 | #include "ltt-tracer-core.h" |
596c4223 | 40 | #include "jhash.h" |
8f3f8c99 | 41 | #include "error.h" |
b0c4126f | 42 | |
f99be407 PMF |
43 | /* Set to 1 to enable tracepoint debug output */ |
44 | static const int tracepoint_debug; | |
b27f8e75 MD |
45 | static int initialized; |
46 | static void (*new_tracepoint_cb)(struct tracepoint *); | |
f99be407 | 47 | |
efa2c591 MD |
48 | /* |
49 | * libraries that contain tracepoints (struct tracepoint_lib). | |
50 | * Protected by UST lock. | |
51 | */ | |
0222e121 | 52 | static CDS_LIST_HEAD(libs); |
474d745f | 53 | |
f99be407 | 54 | /* |
17dfb34b MD |
55 | * The UST lock protects the library tracepoints, the hash table, and |
56 | * the library list. | |
57 | * All calls to the tracepoint API must be protected by the UST lock, | |
58 | * excepts calls to tracepoint_register_lib and | |
59 | * tracepoint_unregister_lib, which take the UST lock themselves. | |
f99be407 | 60 | */ |
f99be407 PMF |
61 | |
62 | /* | |
63 | * Tracepoint hash table, containing the active tracepoints. | |
efa2c591 | 64 | * Protected by ust lock. |
f99be407 PMF |
65 | */ |
66 | #define TRACEPOINT_HASH_BITS 6 | |
67 | #define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS) | |
10c56168 | 68 | static struct cds_hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE]; |
f99be407 | 69 | |
b27f8e75 MD |
70 | static CDS_LIST_HEAD(old_probes); |
71 | static int need_update; | |
72 | ||
f99be407 PMF |
73 | /* |
74 | * Note about RCU : | |
75 | * It is used to to delay the free of multiple probes array until a quiescent | |
76 | * state is reached. | |
efa2c591 | 77 | * Tracepoint entries modifications are protected by the ust lock. |
f99be407 PMF |
78 | */ |
79 | struct tracepoint_entry { | |
10c56168 | 80 | struct cds_hlist_node hlist; |
b979b346 | 81 | struct tracepoint_probe *probes; |
f99be407 PMF |
82 | int refcount; /* Number of times armed. 0 if disarmed. */ |
83 | char name[0]; | |
84 | }; | |
85 | ||
86 | struct tp_probes { | |
87 | union { | |
0222e121 | 88 | struct cds_list_head list; |
f99be407 | 89 | } u; |
b979b346 | 90 | struct tracepoint_probe probes[0]; |
f99be407 PMF |
91 | }; |
92 | ||
efa2c591 | 93 | static void *allocate_probes(int count) |
f99be407 | 94 | { |
b979b346 | 95 | struct tp_probes *p = zmalloc(count * sizeof(struct tracepoint_probe) |
909bc43f | 96 | + sizeof(struct tp_probes)); |
f99be407 PMF |
97 | return p == NULL ? NULL : p->probes; |
98 | } | |
99 | ||
efa2c591 | 100 | static void release_probes(void *old) |
f99be407 PMF |
101 | { |
102 | if (old) { | |
b728d87e | 103 | struct tp_probes *tp_probes = caa_container_of(old, |
f99be407 | 104 | struct tp_probes, probes[0]); |
474d745f | 105 | synchronize_rcu(); |
909bc43f | 106 | free(tp_probes); |
f99be407 PMF |
107 | } |
108 | } | |
109 | ||
110 | static void debug_print_probes(struct tracepoint_entry *entry) | |
111 | { | |
112 | int i; | |
113 | ||
9dec086e | 114 | if (!tracepoint_debug || !entry->probes) |
f99be407 PMF |
115 | return; |
116 | ||
9dec086e NC |
117 | for (i = 0; entry->probes[i].func; i++) |
118 | DBG("Probe %d : %p", i, entry->probes[i].func); | |
f99be407 PMF |
119 | } |
120 | ||
121 | static void * | |
9dec086e NC |
122 | tracepoint_entry_add_probe(struct tracepoint_entry *entry, |
123 | void *probe, void *data) | |
f99be407 PMF |
124 | { |
125 | int nr_probes = 0; | |
b979b346 | 126 | struct tracepoint_probe *old, *new; |
f99be407 PMF |
127 | |
128 | WARN_ON(!probe); | |
129 | ||
130 | debug_print_probes(entry); | |
9dec086e | 131 | old = entry->probes; |
f99be407 PMF |
132 | if (old) { |
133 | /* (N -> N+1), (N != 0, 1) probes */ | |
9dec086e NC |
134 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) |
135 | if (old[nr_probes].func == probe && | |
136 | old[nr_probes].data == data) | |
f99be407 PMF |
137 | return ERR_PTR(-EEXIST); |
138 | } | |
139 | /* + 2 : one for new probe, one for NULL func */ | |
140 | new = allocate_probes(nr_probes + 2); | |
141 | if (new == NULL) | |
142 | return ERR_PTR(-ENOMEM); | |
143 | if (old) | |
b979b346 | 144 | memcpy(new, old, nr_probes * sizeof(struct tracepoint_probe)); |
9dec086e NC |
145 | new[nr_probes].func = probe; |
146 | new[nr_probes].data = data; | |
147 | new[nr_probes + 1].func = NULL; | |
f99be407 | 148 | entry->refcount = nr_probes + 1; |
9dec086e | 149 | entry->probes = new; |
f99be407 PMF |
150 | debug_print_probes(entry); |
151 | return old; | |
152 | } | |
153 | ||
154 | static void * | |
9dec086e NC |
155 | tracepoint_entry_remove_probe(struct tracepoint_entry *entry, void *probe, |
156 | void *data) | |
f99be407 PMF |
157 | { |
158 | int nr_probes = 0, nr_del = 0, i; | |
b979b346 | 159 | struct tracepoint_probe *old, *new; |
f99be407 | 160 | |
9dec086e | 161 | old = entry->probes; |
f99be407 PMF |
162 | |
163 | if (!old) | |
164 | return ERR_PTR(-ENOENT); | |
165 | ||
166 | debug_print_probes(entry); | |
167 | /* (N -> M), (N > 1, M >= 0) probes */ | |
9dec086e | 168 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) { |
c66428ac DG |
169 | if (!probe || |
170 | (old[nr_probes].func == probe && | |
9dec086e | 171 | old[nr_probes].data == data)) |
f99be407 PMF |
172 | nr_del++; |
173 | } | |
174 | ||
175 | if (nr_probes - nr_del == 0) { | |
176 | /* N -> 0, (N > 1) */ | |
9dec086e | 177 | entry->probes = NULL; |
f99be407 PMF |
178 | entry->refcount = 0; |
179 | debug_print_probes(entry); | |
180 | return old; | |
181 | } else { | |
182 | int j = 0; | |
183 | /* N -> M, (N > 1, M > 0) */ | |
184 | /* + 1 for NULL */ | |
185 | new = allocate_probes(nr_probes - nr_del + 1); | |
186 | if (new == NULL) | |
187 | return ERR_PTR(-ENOMEM); | |
9dec086e NC |
188 | for (i = 0; old[i].func; i++) |
189 | if (probe && | |
190 | (old[i].func != probe || old[i].data != data)) | |
f99be407 | 191 | new[j++] = old[i]; |
9dec086e | 192 | new[nr_probes - nr_del].func = NULL; |
f99be407 | 193 | entry->refcount = nr_probes - nr_del; |
9dec086e | 194 | entry->probes = new; |
f99be407 PMF |
195 | } |
196 | debug_print_probes(entry); | |
197 | return old; | |
198 | } | |
199 | ||
200 | /* | |
201 | * Get tracepoint if the tracepoint is present in the tracepoint hash table. | |
efa2c591 | 202 | * Must be called with ust lock held. |
f99be407 PMF |
203 | * Returns NULL if not present. |
204 | */ | |
205 | static struct tracepoint_entry *get_tracepoint(const char *name) | |
206 | { | |
10c56168 DG |
207 | struct cds_hlist_head *head; |
208 | struct cds_hlist_node *node; | |
f99be407 | 209 | struct tracepoint_entry *e; |
23c8854a | 210 | uint32_t hash = jhash(name, strlen(name), 0); |
f99be407 PMF |
211 | |
212 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; | |
10c56168 | 213 | cds_hlist_for_each_entry(e, node, head, hlist) { |
f99be407 PMF |
214 | if (!strcmp(name, e->name)) |
215 | return e; | |
216 | } | |
217 | return NULL; | |
218 | } | |
219 | ||
220 | /* | |
221 | * Add the tracepoint to the tracepoint hash table. Must be called with | |
efa2c591 | 222 | * ust lock held. |
f99be407 PMF |
223 | */ |
224 | static struct tracepoint_entry *add_tracepoint(const char *name) | |
225 | { | |
10c56168 DG |
226 | struct cds_hlist_head *head; |
227 | struct cds_hlist_node *node; | |
f99be407 PMF |
228 | struct tracepoint_entry *e; |
229 | size_t name_len = strlen(name) + 1; | |
23c8854a | 230 | uint32_t hash = jhash(name, name_len-1, 0); |
f99be407 PMF |
231 | |
232 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; | |
10c56168 | 233 | cds_hlist_for_each_entry(e, node, head, hlist) { |
f99be407 | 234 | if (!strcmp(name, e->name)) { |
c1f20530 | 235 | DBG("tracepoint %s busy", name); |
f99be407 PMF |
236 | return ERR_PTR(-EEXIST); /* Already there */ |
237 | } | |
238 | } | |
239 | /* | |
1dba3e6c | 240 | * Using zmalloc here to allocate a variable length element. Could |
f99be407 PMF |
241 | * cause some memory fragmentation if overused. |
242 | */ | |
1dba3e6c | 243 | e = zmalloc(sizeof(struct tracepoint_entry) + name_len); |
f99be407 PMF |
244 | if (!e) |
245 | return ERR_PTR(-ENOMEM); | |
246 | memcpy(&e->name[0], name, name_len); | |
9dec086e | 247 | e->probes = NULL; |
f99be407 | 248 | e->refcount = 0; |
10c56168 | 249 | cds_hlist_add_head(&e->hlist, head); |
f99be407 PMF |
250 | return e; |
251 | } | |
252 | ||
253 | /* | |
254 | * Remove the tracepoint from the tracepoint hash table. Must be called with | |
17dfb34b | 255 | * ust_lock held. |
f99be407 | 256 | */ |
efa2c591 | 257 | static void remove_tracepoint(struct tracepoint_entry *e) |
f99be407 | 258 | { |
10c56168 | 259 | cds_hlist_del(&e->hlist); |
909bc43f | 260 | free(e); |
f99be407 PMF |
261 | } |
262 | ||
263 | /* | |
264 | * Sets the probe callback corresponding to one tracepoint. | |
265 | */ | |
266 | static void set_tracepoint(struct tracepoint_entry **entry, | |
267 | struct tracepoint *elem, int active) | |
268 | { | |
269 | WARN_ON(strcmp((*entry)->name, elem->name) != 0); | |
270 | ||
271 | /* | |
0222e121 | 272 | * rcu_assign_pointer has a cmm_smp_wmb() which makes sure that the new |
f99be407 PMF |
273 | * probe callbacks array is consistent before setting a pointer to it. |
274 | * This array is referenced by __DO_TRACE from | |
0222e121 | 275 | * include/linux/tracepoints.h. A matching cmm_smp_read_barrier_depends() |
f99be407 PMF |
276 | * is used. |
277 | */ | |
9dec086e | 278 | rcu_assign_pointer(elem->probes, (*entry)->probes); |
f36c12ab | 279 | elem->state = active; |
f99be407 PMF |
280 | } |
281 | ||
282 | /* | |
283 | * Disable a tracepoint and its probe callback. | |
284 | * Note: only waiting an RCU period after setting elem->call to the empty | |
285 | * function insures that the original callback is not used anymore. This insured | |
286 | * by preempt_disable around the call site. | |
287 | */ | |
288 | static void disable_tracepoint(struct tracepoint *elem) | |
289 | { | |
f36c12ab | 290 | elem->state = 0; |
9dec086e | 291 | rcu_assign_pointer(elem->probes, NULL); |
f99be407 PMF |
292 | } |
293 | ||
294 | /** | |
295 | * tracepoint_update_probe_range - Update a probe range | |
296 | * @begin: beginning of the range | |
297 | * @end: end of the range | |
298 | * | |
299 | * Updates the probe callback corresponding to a range of tracepoints. | |
300 | */ | |
b27f8e75 | 301 | static |
f218ff28 MD |
302 | void tracepoint_update_probe_range(struct tracepoint * const *begin, |
303 | struct tracepoint * const *end) | |
f99be407 | 304 | { |
f218ff28 | 305 | struct tracepoint * const *iter; |
f99be407 PMF |
306 | struct tracepoint_entry *mark_entry; |
307 | ||
f99be407 | 308 | for (iter = begin; iter < end; iter++) { |
f08ebbe2 MD |
309 | if (!*iter) |
310 | continue; /* skip dummy */ | |
f218ff28 MD |
311 | if (!(*iter)->name) { |
312 | disable_tracepoint(*iter); | |
9dec086e NC |
313 | continue; |
314 | } | |
f218ff28 | 315 | mark_entry = get_tracepoint((*iter)->name); |
f99be407 | 316 | if (mark_entry) { |
f218ff28 | 317 | set_tracepoint(&mark_entry, *iter, |
f99be407 PMF |
318 | !!mark_entry->refcount); |
319 | } else { | |
f218ff28 | 320 | disable_tracepoint(*iter); |
f99be407 PMF |
321 | } |
322 | } | |
f99be407 PMF |
323 | } |
324 | ||
772030fe PMF |
325 | static void lib_update_tracepoints(void) |
326 | { | |
327 | struct tracepoint_lib *lib; | |
328 | ||
b27f8e75 | 329 | cds_list_for_each_entry(lib, &libs, list) { |
772030fe PMF |
330 | tracepoint_update_probe_range(lib->tracepoints_start, |
331 | lib->tracepoints_start + lib->tracepoints_count); | |
b27f8e75 | 332 | } |
772030fe PMF |
333 | } |
334 | ||
f99be407 PMF |
335 | /* |
336 | * Update probes, removing the faulty probes. | |
337 | */ | |
338 | static void tracepoint_update_probes(void) | |
339 | { | |
b27f8e75 | 340 | /* tracepoints registered from libraries and executable. */ |
474d745f | 341 | lib_update_tracepoints(); |
f99be407 PMF |
342 | } |
343 | ||
b979b346 | 344 | static struct tracepoint_probe * |
9dec086e | 345 | tracepoint_add_probe(const char *name, void *probe, void *data) |
f99be407 PMF |
346 | { |
347 | struct tracepoint_entry *entry; | |
b979b346 | 348 | struct tracepoint_probe *old; |
f99be407 PMF |
349 | |
350 | entry = get_tracepoint(name); | |
351 | if (!entry) { | |
352 | entry = add_tracepoint(name); | |
353 | if (IS_ERR(entry)) | |
b979b346 | 354 | return (struct tracepoint_probe *)entry; |
f99be407 | 355 | } |
9dec086e | 356 | old = tracepoint_entry_add_probe(entry, probe, data); |
f99be407 PMF |
357 | if (IS_ERR(old) && !entry->refcount) |
358 | remove_tracepoint(entry); | |
359 | return old; | |
360 | } | |
361 | ||
362 | /** | |
81614639 | 363 | * __tracepoint_probe_register - Connect a probe to a tracepoint |
f99be407 PMF |
364 | * @name: tracepoint name |
365 | * @probe: probe handler | |
366 | * | |
367 | * Returns 0 if ok, error value on error. | |
368 | * The probe address must at least be aligned on the architecture pointer size. | |
17dfb34b | 369 | * Called with the UST lock held. |
f99be407 | 370 | */ |
81614639 | 371 | int __tracepoint_probe_register(const char *name, void *probe, void *data) |
f99be407 PMF |
372 | { |
373 | void *old; | |
374 | ||
9dec086e | 375 | old = tracepoint_add_probe(name, probe, data); |
f99be407 PMF |
376 | if (IS_ERR(old)) |
377 | return PTR_ERR(old); | |
378 | ||
379 | tracepoint_update_probes(); /* may update entry */ | |
380 | release_probes(old); | |
381 | return 0; | |
382 | } | |
f99be407 | 383 | |
9dec086e | 384 | static void *tracepoint_remove_probe(const char *name, void *probe, void *data) |
f99be407 PMF |
385 | { |
386 | struct tracepoint_entry *entry; | |
387 | void *old; | |
388 | ||
389 | entry = get_tracepoint(name); | |
390 | if (!entry) | |
391 | return ERR_PTR(-ENOENT); | |
9dec086e | 392 | old = tracepoint_entry_remove_probe(entry, probe, data); |
f99be407 PMF |
393 | if (IS_ERR(old)) |
394 | return old; | |
395 | if (!entry->refcount) | |
396 | remove_tracepoint(entry); | |
397 | return old; | |
398 | } | |
399 | ||
400 | /** | |
401 | * tracepoint_probe_unregister - Disconnect a probe from a tracepoint | |
402 | * @name: tracepoint name | |
403 | * @probe: probe function pointer | |
9dec086e | 404 | * @probe: probe data pointer |
f99be407 | 405 | * |
17dfb34b | 406 | * Called with the UST lock held. |
f99be407 | 407 | */ |
81614639 | 408 | int __tracepoint_probe_unregister(const char *name, void *probe, void *data) |
f99be407 PMF |
409 | { |
410 | void *old; | |
411 | ||
9dec086e | 412 | old = tracepoint_remove_probe(name, probe, data); |
f99be407 PMF |
413 | if (IS_ERR(old)) |
414 | return PTR_ERR(old); | |
415 | ||
416 | tracepoint_update_probes(); /* may update entry */ | |
417 | release_probes(old); | |
418 | return 0; | |
419 | } | |
f99be407 | 420 | |
f99be407 PMF |
421 | static void tracepoint_add_old_probes(void *old) |
422 | { | |
423 | need_update = 1; | |
424 | if (old) { | |
b728d87e | 425 | struct tp_probes *tp_probes = caa_container_of(old, |
f99be407 | 426 | struct tp_probes, probes[0]); |
0222e121 | 427 | cds_list_add(&tp_probes->u.list, &old_probes); |
f99be407 PMF |
428 | } |
429 | } | |
430 | ||
431 | /** | |
432 | * tracepoint_probe_register_noupdate - register a probe but not connect | |
433 | * @name: tracepoint name | |
434 | * @probe: probe handler | |
435 | * | |
436 | * caller must call tracepoint_probe_update_all() | |
17dfb34b | 437 | * Called with the UST lock held. |
f99be407 | 438 | */ |
9dec086e NC |
439 | int tracepoint_probe_register_noupdate(const char *name, void *probe, |
440 | void *data) | |
f99be407 PMF |
441 | { |
442 | void *old; | |
443 | ||
9dec086e | 444 | old = tracepoint_add_probe(name, probe, data); |
f99be407 | 445 | if (IS_ERR(old)) { |
f99be407 PMF |
446 | return PTR_ERR(old); |
447 | } | |
448 | tracepoint_add_old_probes(old); | |
f99be407 PMF |
449 | return 0; |
450 | } | |
f99be407 PMF |
451 | |
452 | /** | |
453 | * tracepoint_probe_unregister_noupdate - remove a probe but not disconnect | |
454 | * @name: tracepoint name | |
455 | * @probe: probe function pointer | |
456 | * | |
457 | * caller must call tracepoint_probe_update_all() | |
17dfb34b | 458 | * Called with the UST lock held. |
f99be407 | 459 | */ |
9dec086e NC |
460 | int tracepoint_probe_unregister_noupdate(const char *name, void *probe, |
461 | void *data) | |
f99be407 PMF |
462 | { |
463 | void *old; | |
464 | ||
9dec086e | 465 | old = tracepoint_remove_probe(name, probe, data); |
f99be407 | 466 | if (IS_ERR(old)) { |
f99be407 PMF |
467 | return PTR_ERR(old); |
468 | } | |
469 | tracepoint_add_old_probes(old); | |
f99be407 PMF |
470 | return 0; |
471 | } | |
f99be407 PMF |
472 | |
473 | /** | |
474 | * tracepoint_probe_update_all - update tracepoints | |
17dfb34b | 475 | * Called with the UST lock held. |
f99be407 PMF |
476 | */ |
477 | void tracepoint_probe_update_all(void) | |
478 | { | |
0222e121 | 479 | CDS_LIST_HEAD(release_probes); |
f99be407 PMF |
480 | struct tp_probes *pos, *next; |
481 | ||
f99be407 | 482 | if (!need_update) { |
f99be407 PMF |
483 | return; |
484 | } | |
0222e121 MD |
485 | if (!cds_list_empty(&old_probes)) |
486 | cds_list_replace_init(&old_probes, &release_probes); | |
f99be407 | 487 | need_update = 0; |
f99be407 PMF |
488 | |
489 | tracepoint_update_probes(); | |
0222e121 MD |
490 | cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) { |
491 | cds_list_del(&pos->u.list); | |
474d745f | 492 | synchronize_rcu(); |
909bc43f | 493 | free(pos); |
f99be407 PMF |
494 | } |
495 | } | |
f99be407 | 496 | |
474d745f PMF |
497 | void tracepoint_set_new_tracepoint_cb(void (*cb)(struct tracepoint *)) |
498 | { | |
499 | new_tracepoint_cb = cb; | |
500 | } | |
f99be407 | 501 | |
f218ff28 | 502 | static void new_tracepoints(struct tracepoint * const *start, struct tracepoint * const *end) |
f99be407 | 503 | { |
f218ff28 MD |
504 | if (new_tracepoint_cb) { |
505 | struct tracepoint * const *t; | |
f08ebbe2 | 506 | |
b27f8e75 | 507 | for (t = start; t < end; t++) { |
f08ebbe2 MD |
508 | if (*t) |
509 | new_tracepoint_cb(*t); | |
474d745f PMF |
510 | } |
511 | } | |
f99be407 | 512 | } |
f99be407 | 513 | |
b27f8e75 MD |
514 | int tracepoint_register_lib(struct tracepoint * const *tracepoints_start, |
515 | int tracepoints_count) | |
474d745f | 516 | { |
b467f7a7 | 517 | struct tracepoint_lib *pl, *iter; |
474d745f | 518 | |
edaa1431 MD |
519 | init_tracepoint(); |
520 | ||
1dba3e6c | 521 | pl = (struct tracepoint_lib *) zmalloc(sizeof(struct tracepoint_lib)); |
474d745f PMF |
522 | |
523 | pl->tracepoints_start = tracepoints_start; | |
524 | pl->tracepoints_count = tracepoints_count; | |
525 | ||
17dfb34b | 526 | ust_lock(); |
b467f7a7 MD |
527 | /* |
528 | * We sort the libs by struct lib pointer address. | |
529 | */ | |
530 | cds_list_for_each_entry_reverse(iter, &libs, list) { | |
531 | BUG_ON(iter == pl); /* Should never be in the list twice */ | |
532 | if (iter < pl) { | |
533 | /* We belong to the location right after iter. */ | |
534 | cds_list_add(&pl->list, &iter->list); | |
535 | goto lib_added; | |
536 | } | |
537 | } | |
538 | /* We should be added at the head of the list */ | |
0222e121 | 539 | cds_list_add(&pl->list, &libs); |
b467f7a7 | 540 | lib_added: |
474d745f PMF |
541 | new_tracepoints(tracepoints_start, tracepoints_start + tracepoints_count); |
542 | ||
b27f8e75 | 543 | /* TODO: update just the loaded lib */ |
474d745f | 544 | lib_update_tracepoints(); |
17dfb34b | 545 | ust_unlock(); |
474d745f | 546 | |
1fcf7ad7 MD |
547 | DBG("just registered a tracepoints section from %p and having %d tracepoints", |
548 | tracepoints_start, tracepoints_count); | |
9dec086e | 549 | |
474d745f PMF |
550 | return 0; |
551 | } | |
552 | ||
f218ff28 | 553 | int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start) |
474d745f | 554 | { |
24b6668c PMF |
555 | struct tracepoint_lib *lib; |
556 | ||
17dfb34b | 557 | ust_lock(); |
0222e121 | 558 | cds_list_for_each_entry(lib, &libs, list) { |
f218ff28 | 559 | if (lib->tracepoints_start == tracepoints_start) { |
24b6668c | 560 | struct tracepoint_lib *lib2free = lib; |
0222e121 | 561 | cds_list_del(&lib->list); |
24b6668c PMF |
562 | free(lib2free); |
563 | break; | |
564 | } | |
565 | } | |
17dfb34b | 566 | ust_unlock(); |
474d745f PMF |
567 | |
568 | return 0; | |
569 | } | |
b27f8e75 | 570 | |
edaa1431 | 571 | void init_tracepoint(void) |
b27f8e75 | 572 | { |
edaa1431 MD |
573 | if (uatomic_xchg(&initialized, 1) == 1) |
574 | return; | |
5e96a467 | 575 | init_usterr(); |
b27f8e75 MD |
576 | } |
577 | ||
edaa1431 | 578 | void exit_tracepoint(void) |
b27f8e75 | 579 | { |
17dfb34b | 580 | initialized = 0; |
b27f8e75 | 581 | } |