Commit | Line | Data |
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97e1c18e MD |
1 | /* |
2 | * Copyright (C) 2008 Mathieu Desnoyers | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, write to the Free Software | |
16 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
17 | */ | |
18 | #include <linux/module.h> | |
19 | #include <linux/mutex.h> | |
20 | #include <linux/types.h> | |
21 | #include <linux/jhash.h> | |
22 | #include <linux/list.h> | |
23 | #include <linux/rcupdate.h> | |
24 | #include <linux/tracepoint.h> | |
25 | #include <linux/err.h> | |
26 | #include <linux/slab.h> | |
a871bd33 | 27 | #include <linux/sched.h> |
97e1c18e MD |
28 | |
29 | extern struct tracepoint __start___tracepoints[]; | |
30 | extern struct tracepoint __stop___tracepoints[]; | |
31 | ||
32 | /* Set to 1 to enable tracepoint debug output */ | |
33 | static const int tracepoint_debug; | |
34 | ||
35 | /* | |
36 | * tracepoints_mutex nests inside module_mutex. Tracepoints mutex protects the | |
37 | * builtin and module tracepoints and the hash table. | |
38 | */ | |
39 | static DEFINE_MUTEX(tracepoints_mutex); | |
40 | ||
41 | /* | |
42 | * Tracepoint hash table, containing the active tracepoints. | |
43 | * Protected by tracepoints_mutex. | |
44 | */ | |
45 | #define TRACEPOINT_HASH_BITS 6 | |
46 | #define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS) | |
19dba33c | 47 | static struct hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE]; |
97e1c18e MD |
48 | |
49 | /* | |
50 | * Note about RCU : | |
fd589a8f | 51 | * It is used to delay the free of multiple probes array until a quiescent |
97e1c18e MD |
52 | * state is reached. |
53 | * Tracepoint entries modifications are protected by the tracepoints_mutex. | |
54 | */ | |
55 | struct tracepoint_entry { | |
56 | struct hlist_node hlist; | |
38516ab5 | 57 | struct tracepoint_func *funcs; |
97e1c18e | 58 | int refcount; /* Number of times armed. 0 if disarmed. */ |
97e1c18e MD |
59 | char name[0]; |
60 | }; | |
61 | ||
19dba33c | 62 | struct tp_probes { |
127cafbb LJ |
63 | union { |
64 | struct rcu_head rcu; | |
65 | struct list_head list; | |
66 | } u; | |
38516ab5 | 67 | struct tracepoint_func probes[0]; |
19dba33c | 68 | }; |
97e1c18e | 69 | |
19dba33c | 70 | static inline void *allocate_probes(int count) |
97e1c18e | 71 | { |
38516ab5 | 72 | struct tp_probes *p = kmalloc(count * sizeof(struct tracepoint_func) |
19dba33c LJ |
73 | + sizeof(struct tp_probes), GFP_KERNEL); |
74 | return p == NULL ? NULL : p->probes; | |
97e1c18e MD |
75 | } |
76 | ||
19dba33c | 77 | static void rcu_free_old_probes(struct rcu_head *head) |
97e1c18e | 78 | { |
127cafbb | 79 | kfree(container_of(head, struct tp_probes, u.rcu)); |
19dba33c LJ |
80 | } |
81 | ||
38516ab5 | 82 | static inline void release_probes(struct tracepoint_func *old) |
19dba33c LJ |
83 | { |
84 | if (old) { | |
85 | struct tp_probes *tp_probes = container_of(old, | |
86 | struct tp_probes, probes[0]); | |
127cafbb | 87 | call_rcu_sched(&tp_probes->u.rcu, rcu_free_old_probes); |
19dba33c | 88 | } |
97e1c18e MD |
89 | } |
90 | ||
91 | static void debug_print_probes(struct tracepoint_entry *entry) | |
92 | { | |
93 | int i; | |
94 | ||
19dba33c | 95 | if (!tracepoint_debug || !entry->funcs) |
97e1c18e MD |
96 | return; |
97 | ||
38516ab5 SR |
98 | for (i = 0; entry->funcs[i].func; i++) |
99 | printk(KERN_DEBUG "Probe %d : %p\n", i, entry->funcs[i].func); | |
97e1c18e MD |
100 | } |
101 | ||
38516ab5 SR |
102 | static struct tracepoint_func * |
103 | tracepoint_entry_add_probe(struct tracepoint_entry *entry, | |
104 | void *probe, void *data) | |
97e1c18e MD |
105 | { |
106 | int nr_probes = 0; | |
38516ab5 | 107 | struct tracepoint_func *old, *new; |
97e1c18e MD |
108 | |
109 | WARN_ON(!probe); | |
110 | ||
111 | debug_print_probes(entry); | |
112 | old = entry->funcs; | |
113 | if (old) { | |
114 | /* (N -> N+1), (N != 0, 1) probes */ | |
38516ab5 SR |
115 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) |
116 | if (old[nr_probes].func == probe && | |
117 | old[nr_probes].data == data) | |
97e1c18e MD |
118 | return ERR_PTR(-EEXIST); |
119 | } | |
120 | /* + 2 : one for new probe, one for NULL func */ | |
19dba33c | 121 | new = allocate_probes(nr_probes + 2); |
97e1c18e MD |
122 | if (new == NULL) |
123 | return ERR_PTR(-ENOMEM); | |
124 | if (old) | |
38516ab5 SR |
125 | memcpy(new, old, nr_probes * sizeof(struct tracepoint_func)); |
126 | new[nr_probes].func = probe; | |
127 | new[nr_probes].data = data; | |
128 | new[nr_probes + 1].func = NULL; | |
97e1c18e MD |
129 | entry->refcount = nr_probes + 1; |
130 | entry->funcs = new; | |
131 | debug_print_probes(entry); | |
132 | return old; | |
133 | } | |
134 | ||
135 | static void * | |
38516ab5 SR |
136 | tracepoint_entry_remove_probe(struct tracepoint_entry *entry, |
137 | void *probe, void *data) | |
97e1c18e MD |
138 | { |
139 | int nr_probes = 0, nr_del = 0, i; | |
38516ab5 | 140 | struct tracepoint_func *old, *new; |
97e1c18e MD |
141 | |
142 | old = entry->funcs; | |
143 | ||
f66af459 | 144 | if (!old) |
19dba33c | 145 | return ERR_PTR(-ENOENT); |
f66af459 | 146 | |
97e1c18e MD |
147 | debug_print_probes(entry); |
148 | /* (N -> M), (N > 1, M >= 0) probes */ | |
38516ab5 SR |
149 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) { |
150 | if (!probe || | |
151 | (old[nr_probes].func == probe && | |
152 | old[nr_probes].data == data)) | |
97e1c18e MD |
153 | nr_del++; |
154 | } | |
155 | ||
156 | if (nr_probes - nr_del == 0) { | |
157 | /* N -> 0, (N > 1) */ | |
158 | entry->funcs = NULL; | |
159 | entry->refcount = 0; | |
160 | debug_print_probes(entry); | |
161 | return old; | |
162 | } else { | |
163 | int j = 0; | |
164 | /* N -> M, (N > 1, M > 0) */ | |
165 | /* + 1 for NULL */ | |
19dba33c | 166 | new = allocate_probes(nr_probes - nr_del + 1); |
97e1c18e MD |
167 | if (new == NULL) |
168 | return ERR_PTR(-ENOMEM); | |
38516ab5 SR |
169 | for (i = 0; old[i].func; i++) |
170 | if (probe && | |
171 | (old[i].func != probe || old[i].data != data)) | |
97e1c18e | 172 | new[j++] = old[i]; |
38516ab5 | 173 | new[nr_probes - nr_del].func = NULL; |
97e1c18e MD |
174 | entry->refcount = nr_probes - nr_del; |
175 | entry->funcs = new; | |
176 | } | |
177 | debug_print_probes(entry); | |
178 | return old; | |
179 | } | |
180 | ||
181 | /* | |
182 | * Get tracepoint if the tracepoint is present in the tracepoint hash table. | |
183 | * Must be called with tracepoints_mutex held. | |
184 | * Returns NULL if not present. | |
185 | */ | |
186 | static struct tracepoint_entry *get_tracepoint(const char *name) | |
187 | { | |
188 | struct hlist_head *head; | |
189 | struct hlist_node *node; | |
190 | struct tracepoint_entry *e; | |
191 | u32 hash = jhash(name, strlen(name), 0); | |
192 | ||
9795302a | 193 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
97e1c18e MD |
194 | hlist_for_each_entry(e, node, head, hlist) { |
195 | if (!strcmp(name, e->name)) | |
196 | return e; | |
197 | } | |
198 | return NULL; | |
199 | } | |
200 | ||
201 | /* | |
202 | * Add the tracepoint to the tracepoint hash table. Must be called with | |
203 | * tracepoints_mutex held. | |
204 | */ | |
205 | static struct tracepoint_entry *add_tracepoint(const char *name) | |
206 | { | |
207 | struct hlist_head *head; | |
208 | struct hlist_node *node; | |
209 | struct tracepoint_entry *e; | |
210 | size_t name_len = strlen(name) + 1; | |
211 | u32 hash = jhash(name, name_len-1, 0); | |
212 | ||
9795302a | 213 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
97e1c18e MD |
214 | hlist_for_each_entry(e, node, head, hlist) { |
215 | if (!strcmp(name, e->name)) { | |
216 | printk(KERN_NOTICE | |
217 | "tracepoint %s busy\n", name); | |
218 | return ERR_PTR(-EEXIST); /* Already there */ | |
219 | } | |
220 | } | |
221 | /* | |
222 | * Using kmalloc here to allocate a variable length element. Could | |
223 | * cause some memory fragmentation if overused. | |
224 | */ | |
225 | e = kmalloc(sizeof(struct tracepoint_entry) + name_len, GFP_KERNEL); | |
226 | if (!e) | |
227 | return ERR_PTR(-ENOMEM); | |
228 | memcpy(&e->name[0], name, name_len); | |
229 | e->funcs = NULL; | |
230 | e->refcount = 0; | |
97e1c18e MD |
231 | hlist_add_head(&e->hlist, head); |
232 | return e; | |
233 | } | |
234 | ||
235 | /* | |
236 | * Remove the tracepoint from the tracepoint hash table. Must be called with | |
237 | * mutex_lock held. | |
238 | */ | |
19dba33c | 239 | static inline void remove_tracepoint(struct tracepoint_entry *e) |
97e1c18e | 240 | { |
97e1c18e | 241 | hlist_del(&e->hlist); |
97e1c18e | 242 | kfree(e); |
97e1c18e MD |
243 | } |
244 | ||
245 | /* | |
246 | * Sets the probe callback corresponding to one tracepoint. | |
247 | */ | |
248 | static void set_tracepoint(struct tracepoint_entry **entry, | |
249 | struct tracepoint *elem, int active) | |
250 | { | |
251 | WARN_ON(strcmp((*entry)->name, elem->name) != 0); | |
252 | ||
97419875 JS |
253 | if (elem->regfunc && !elem->state && active) |
254 | elem->regfunc(); | |
255 | else if (elem->unregfunc && elem->state && !active) | |
256 | elem->unregfunc(); | |
257 | ||
97e1c18e MD |
258 | /* |
259 | * rcu_assign_pointer has a smp_wmb() which makes sure that the new | |
260 | * probe callbacks array is consistent before setting a pointer to it. | |
261 | * This array is referenced by __DO_TRACE from | |
262 | * include/linux/tracepoints.h. A matching smp_read_barrier_depends() | |
263 | * is used. | |
264 | */ | |
265 | rcu_assign_pointer(elem->funcs, (*entry)->funcs); | |
266 | elem->state = active; | |
267 | } | |
268 | ||
269 | /* | |
270 | * Disable a tracepoint and its probe callback. | |
271 | * Note: only waiting an RCU period after setting elem->call to the empty | |
272 | * function insures that the original callback is not used anymore. This insured | |
273 | * by preempt_disable around the call site. | |
274 | */ | |
275 | static void disable_tracepoint(struct tracepoint *elem) | |
276 | { | |
97419875 JS |
277 | if (elem->unregfunc && elem->state) |
278 | elem->unregfunc(); | |
279 | ||
97e1c18e | 280 | elem->state = 0; |
de0baf9a | 281 | rcu_assign_pointer(elem->funcs, NULL); |
97e1c18e MD |
282 | } |
283 | ||
284 | /** | |
285 | * tracepoint_update_probe_range - Update a probe range | |
286 | * @begin: beginning of the range | |
287 | * @end: end of the range | |
288 | * | |
289 | * Updates the probe callback corresponding to a range of tracepoints. | |
290 | */ | |
09933a10 JSR |
291 | void |
292 | tracepoint_update_probe_range(struct tracepoint *begin, struct tracepoint *end) | |
97e1c18e MD |
293 | { |
294 | struct tracepoint *iter; | |
295 | struct tracepoint_entry *mark_entry; | |
296 | ||
ec625cb2 | 297 | if (!begin) |
09933a10 | 298 | return; |
09933a10 | 299 | |
97e1c18e MD |
300 | mutex_lock(&tracepoints_mutex); |
301 | for (iter = begin; iter < end; iter++) { | |
302 | mark_entry = get_tracepoint(iter->name); | |
303 | if (mark_entry) { | |
304 | set_tracepoint(&mark_entry, iter, | |
305 | !!mark_entry->refcount); | |
306 | } else { | |
307 | disable_tracepoint(iter); | |
308 | } | |
309 | } | |
310 | mutex_unlock(&tracepoints_mutex); | |
311 | } | |
312 | ||
313 | /* | |
314 | * Update probes, removing the faulty probes. | |
315 | */ | |
316 | static void tracepoint_update_probes(void) | |
317 | { | |
318 | /* Core kernel tracepoints */ | |
319 | tracepoint_update_probe_range(__start___tracepoints, | |
320 | __stop___tracepoints); | |
321 | /* tracepoints in modules. */ | |
322 | module_update_tracepoints(); | |
323 | } | |
324 | ||
38516ab5 SR |
325 | static struct tracepoint_func * |
326 | tracepoint_add_probe(const char *name, void *probe, void *data) | |
127cafbb LJ |
327 | { |
328 | struct tracepoint_entry *entry; | |
38516ab5 | 329 | struct tracepoint_func *old; |
127cafbb LJ |
330 | |
331 | entry = get_tracepoint(name); | |
332 | if (!entry) { | |
333 | entry = add_tracepoint(name); | |
334 | if (IS_ERR(entry)) | |
38516ab5 | 335 | return (struct tracepoint_func *)entry; |
127cafbb | 336 | } |
38516ab5 | 337 | old = tracepoint_entry_add_probe(entry, probe, data); |
127cafbb LJ |
338 | if (IS_ERR(old) && !entry->refcount) |
339 | remove_tracepoint(entry); | |
340 | return old; | |
341 | } | |
342 | ||
97e1c18e MD |
343 | /** |
344 | * tracepoint_probe_register - Connect a probe to a tracepoint | |
345 | * @name: tracepoint name | |
346 | * @probe: probe handler | |
347 | * | |
348 | * Returns 0 if ok, error value on error. | |
349 | * The probe address must at least be aligned on the architecture pointer size. | |
350 | */ | |
38516ab5 | 351 | int tracepoint_probe_register(const char *name, void *probe, void *data) |
97e1c18e | 352 | { |
38516ab5 | 353 | struct tracepoint_func *old; |
97e1c18e MD |
354 | |
355 | mutex_lock(&tracepoints_mutex); | |
38516ab5 | 356 | old = tracepoint_add_probe(name, probe, data); |
97e1c18e | 357 | mutex_unlock(&tracepoints_mutex); |
127cafbb LJ |
358 | if (IS_ERR(old)) |
359 | return PTR_ERR(old); | |
360 | ||
97e1c18e | 361 | tracepoint_update_probes(); /* may update entry */ |
19dba33c LJ |
362 | release_probes(old); |
363 | return 0; | |
97e1c18e MD |
364 | } |
365 | EXPORT_SYMBOL_GPL(tracepoint_probe_register); | |
366 | ||
38516ab5 SR |
367 | static struct tracepoint_func * |
368 | tracepoint_remove_probe(const char *name, void *probe, void *data) | |
127cafbb LJ |
369 | { |
370 | struct tracepoint_entry *entry; | |
38516ab5 | 371 | struct tracepoint_func *old; |
127cafbb LJ |
372 | |
373 | entry = get_tracepoint(name); | |
374 | if (!entry) | |
375 | return ERR_PTR(-ENOENT); | |
38516ab5 | 376 | old = tracepoint_entry_remove_probe(entry, probe, data); |
127cafbb LJ |
377 | if (IS_ERR(old)) |
378 | return old; | |
379 | if (!entry->refcount) | |
380 | remove_tracepoint(entry); | |
381 | return old; | |
382 | } | |
383 | ||
97e1c18e MD |
384 | /** |
385 | * tracepoint_probe_unregister - Disconnect a probe from a tracepoint | |
386 | * @name: tracepoint name | |
387 | * @probe: probe function pointer | |
388 | * | |
389 | * We do not need to call a synchronize_sched to make sure the probes have | |
390 | * finished running before doing a module unload, because the module unload | |
391 | * itself uses stop_machine(), which insures that every preempt disabled section | |
392 | * have finished. | |
393 | */ | |
38516ab5 | 394 | int tracepoint_probe_unregister(const char *name, void *probe, void *data) |
97e1c18e | 395 | { |
38516ab5 | 396 | struct tracepoint_func *old; |
97e1c18e MD |
397 | |
398 | mutex_lock(&tracepoints_mutex); | |
38516ab5 | 399 | old = tracepoint_remove_probe(name, probe, data); |
97e1c18e | 400 | mutex_unlock(&tracepoints_mutex); |
127cafbb LJ |
401 | if (IS_ERR(old)) |
402 | return PTR_ERR(old); | |
403 | ||
97e1c18e | 404 | tracepoint_update_probes(); /* may update entry */ |
19dba33c LJ |
405 | release_probes(old); |
406 | return 0; | |
97e1c18e MD |
407 | } |
408 | EXPORT_SYMBOL_GPL(tracepoint_probe_unregister); | |
409 | ||
127cafbb LJ |
410 | static LIST_HEAD(old_probes); |
411 | static int need_update; | |
412 | ||
413 | static void tracepoint_add_old_probes(void *old) | |
414 | { | |
415 | need_update = 1; | |
416 | if (old) { | |
417 | struct tp_probes *tp_probes = container_of(old, | |
418 | struct tp_probes, probes[0]); | |
419 | list_add(&tp_probes->u.list, &old_probes); | |
420 | } | |
421 | } | |
422 | ||
423 | /** | |
424 | * tracepoint_probe_register_noupdate - register a probe but not connect | |
425 | * @name: tracepoint name | |
426 | * @probe: probe handler | |
427 | * | |
428 | * caller must call tracepoint_probe_update_all() | |
429 | */ | |
38516ab5 SR |
430 | int tracepoint_probe_register_noupdate(const char *name, void *probe, |
431 | void *data) | |
127cafbb | 432 | { |
38516ab5 | 433 | struct tracepoint_func *old; |
127cafbb LJ |
434 | |
435 | mutex_lock(&tracepoints_mutex); | |
38516ab5 | 436 | old = tracepoint_add_probe(name, probe, data); |
127cafbb LJ |
437 | if (IS_ERR(old)) { |
438 | mutex_unlock(&tracepoints_mutex); | |
439 | return PTR_ERR(old); | |
440 | } | |
441 | tracepoint_add_old_probes(old); | |
442 | mutex_unlock(&tracepoints_mutex); | |
443 | return 0; | |
444 | } | |
445 | EXPORT_SYMBOL_GPL(tracepoint_probe_register_noupdate); | |
446 | ||
447 | /** | |
448 | * tracepoint_probe_unregister_noupdate - remove a probe but not disconnect | |
449 | * @name: tracepoint name | |
450 | * @probe: probe function pointer | |
451 | * | |
452 | * caller must call tracepoint_probe_update_all() | |
453 | */ | |
38516ab5 SR |
454 | int tracepoint_probe_unregister_noupdate(const char *name, void *probe, |
455 | void *data) | |
127cafbb | 456 | { |
38516ab5 | 457 | struct tracepoint_func *old; |
127cafbb LJ |
458 | |
459 | mutex_lock(&tracepoints_mutex); | |
38516ab5 | 460 | old = tracepoint_remove_probe(name, probe, data); |
127cafbb LJ |
461 | if (IS_ERR(old)) { |
462 | mutex_unlock(&tracepoints_mutex); | |
463 | return PTR_ERR(old); | |
464 | } | |
465 | tracepoint_add_old_probes(old); | |
466 | mutex_unlock(&tracepoints_mutex); | |
467 | return 0; | |
468 | } | |
469 | EXPORT_SYMBOL_GPL(tracepoint_probe_unregister_noupdate); | |
470 | ||
471 | /** | |
472 | * tracepoint_probe_update_all - update tracepoints | |
473 | */ | |
474 | void tracepoint_probe_update_all(void) | |
475 | { | |
476 | LIST_HEAD(release_probes); | |
477 | struct tp_probes *pos, *next; | |
478 | ||
479 | mutex_lock(&tracepoints_mutex); | |
480 | if (!need_update) { | |
481 | mutex_unlock(&tracepoints_mutex); | |
482 | return; | |
483 | } | |
484 | if (!list_empty(&old_probes)) | |
485 | list_replace_init(&old_probes, &release_probes); | |
486 | need_update = 0; | |
487 | mutex_unlock(&tracepoints_mutex); | |
488 | ||
489 | tracepoint_update_probes(); | |
490 | list_for_each_entry_safe(pos, next, &release_probes, u.list) { | |
491 | list_del(&pos->u.list); | |
492 | call_rcu_sched(&pos->u.rcu, rcu_free_old_probes); | |
493 | } | |
494 | } | |
495 | EXPORT_SYMBOL_GPL(tracepoint_probe_update_all); | |
496 | ||
97e1c18e MD |
497 | /** |
498 | * tracepoint_get_iter_range - Get a next tracepoint iterator given a range. | |
499 | * @tracepoint: current tracepoints (in), next tracepoint (out) | |
500 | * @begin: beginning of the range | |
501 | * @end: end of the range | |
502 | * | |
503 | * Returns whether a next tracepoint has been found (1) or not (0). | |
504 | * Will return the first tracepoint in the range if the input tracepoint is | |
505 | * NULL. | |
506 | */ | |
507 | int tracepoint_get_iter_range(struct tracepoint **tracepoint, | |
508 | struct tracepoint *begin, struct tracepoint *end) | |
509 | { | |
510 | if (!*tracepoint && begin != end) { | |
511 | *tracepoint = begin; | |
512 | return 1; | |
513 | } | |
514 | if (*tracepoint >= begin && *tracepoint < end) | |
515 | return 1; | |
516 | return 0; | |
517 | } | |
518 | EXPORT_SYMBOL_GPL(tracepoint_get_iter_range); | |
519 | ||
520 | static void tracepoint_get_iter(struct tracepoint_iter *iter) | |
521 | { | |
522 | int found = 0; | |
523 | ||
524 | /* Core kernel tracepoints */ | |
525 | if (!iter->module) { | |
526 | found = tracepoint_get_iter_range(&iter->tracepoint, | |
527 | __start___tracepoints, __stop___tracepoints); | |
528 | if (found) | |
529 | goto end; | |
530 | } | |
531 | /* tracepoints in modules. */ | |
532 | found = module_get_iter_tracepoints(iter); | |
533 | end: | |
534 | if (!found) | |
535 | tracepoint_iter_reset(iter); | |
536 | } | |
537 | ||
538 | void tracepoint_iter_start(struct tracepoint_iter *iter) | |
539 | { | |
540 | tracepoint_get_iter(iter); | |
541 | } | |
542 | EXPORT_SYMBOL_GPL(tracepoint_iter_start); | |
543 | ||
544 | void tracepoint_iter_next(struct tracepoint_iter *iter) | |
545 | { | |
546 | iter->tracepoint++; | |
547 | /* | |
548 | * iter->tracepoint may be invalid because we blindly incremented it. | |
549 | * Make sure it is valid by marshalling on the tracepoints, getting the | |
550 | * tracepoints from following modules if necessary. | |
551 | */ | |
552 | tracepoint_get_iter(iter); | |
553 | } | |
554 | EXPORT_SYMBOL_GPL(tracepoint_iter_next); | |
555 | ||
556 | void tracepoint_iter_stop(struct tracepoint_iter *iter) | |
557 | { | |
558 | } | |
559 | EXPORT_SYMBOL_GPL(tracepoint_iter_stop); | |
560 | ||
561 | void tracepoint_iter_reset(struct tracepoint_iter *iter) | |
562 | { | |
563 | iter->module = NULL; | |
564 | iter->tracepoint = NULL; | |
565 | } | |
566 | EXPORT_SYMBOL_GPL(tracepoint_iter_reset); | |
32f85742 | 567 | |
227a8375 IM |
568 | #ifdef CONFIG_MODULES |
569 | ||
32f85742 MD |
570 | int tracepoint_module_notify(struct notifier_block *self, |
571 | unsigned long val, void *data) | |
572 | { | |
573 | struct module *mod = data; | |
574 | ||
575 | switch (val) { | |
576 | case MODULE_STATE_COMING: | |
32f85742 MD |
577 | case MODULE_STATE_GOING: |
578 | tracepoint_update_probe_range(mod->tracepoints, | |
579 | mod->tracepoints + mod->num_tracepoints); | |
580 | break; | |
581 | } | |
582 | return 0; | |
583 | } | |
584 | ||
585 | struct notifier_block tracepoint_module_nb = { | |
586 | .notifier_call = tracepoint_module_notify, | |
587 | .priority = 0, | |
588 | }; | |
589 | ||
590 | static int init_tracepoints(void) | |
591 | { | |
592 | return register_module_notifier(&tracepoint_module_nb); | |
593 | } | |
594 | __initcall(init_tracepoints); | |
227a8375 IM |
595 | |
596 | #endif /* CONFIG_MODULES */ | |
a871bd33 | 597 | |
3d27d8cb | 598 | #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS |
60d970c2 | 599 | |
97419875 | 600 | /* NB: reg/unreg are called while guarded with the tracepoints_mutex */ |
a871bd33 JB |
601 | static int sys_tracepoint_refcount; |
602 | ||
603 | void syscall_regfunc(void) | |
604 | { | |
605 | unsigned long flags; | |
606 | struct task_struct *g, *t; | |
607 | ||
a871bd33 JB |
608 | if (!sys_tracepoint_refcount) { |
609 | read_lock_irqsave(&tasklist_lock, flags); | |
610 | do_each_thread(g, t) { | |
cc3b13c1 HB |
611 | /* Skip kernel threads. */ |
612 | if (t->mm) | |
613 | set_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT); | |
a871bd33 JB |
614 | } while_each_thread(g, t); |
615 | read_unlock_irqrestore(&tasklist_lock, flags); | |
616 | } | |
617 | sys_tracepoint_refcount++; | |
a871bd33 JB |
618 | } |
619 | ||
620 | void syscall_unregfunc(void) | |
621 | { | |
622 | unsigned long flags; | |
623 | struct task_struct *g, *t; | |
624 | ||
a871bd33 JB |
625 | sys_tracepoint_refcount--; |
626 | if (!sys_tracepoint_refcount) { | |
627 | read_lock_irqsave(&tasklist_lock, flags); | |
628 | do_each_thread(g, t) { | |
66700001 | 629 | clear_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT); |
a871bd33 JB |
630 | } while_each_thread(g, t); |
631 | read_unlock_irqrestore(&tasklist_lock, flags); | |
632 | } | |
a871bd33 | 633 | } |
60d970c2 | 634 | #endif |