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> |
8f7b50c5 | 28 | #include <linux/jump_label.h> |
97e1c18e | 29 | |
65498646 MD |
30 | extern struct tracepoint * const __start___tracepoints_ptrs[]; |
31 | extern struct tracepoint * const __stop___tracepoints_ptrs[]; | |
97e1c18e MD |
32 | |
33 | /* Set to 1 to enable tracepoint debug output */ | |
34 | static const int tracepoint_debug; | |
35 | ||
36 | /* | |
37 | * tracepoints_mutex nests inside module_mutex. Tracepoints mutex protects the | |
38 | * builtin and module tracepoints and the hash table. | |
39 | */ | |
40 | static DEFINE_MUTEX(tracepoints_mutex); | |
41 | ||
42 | /* | |
43 | * Tracepoint hash table, containing the active tracepoints. | |
44 | * Protected by tracepoints_mutex. | |
45 | */ | |
46 | #define TRACEPOINT_HASH_BITS 6 | |
47 | #define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS) | |
19dba33c | 48 | static struct hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE]; |
97e1c18e MD |
49 | |
50 | /* | |
51 | * Note about RCU : | |
fd589a8f | 52 | * It is used to delay the free of multiple probes array until a quiescent |
97e1c18e MD |
53 | * state is reached. |
54 | * Tracepoint entries modifications are protected by the tracepoints_mutex. | |
55 | */ | |
56 | struct tracepoint_entry { | |
57 | struct hlist_node hlist; | |
38516ab5 | 58 | struct tracepoint_func *funcs; |
97e1c18e | 59 | int refcount; /* Number of times armed. 0 if disarmed. */ |
97e1c18e MD |
60 | char name[0]; |
61 | }; | |
62 | ||
19dba33c | 63 | struct tp_probes { |
127cafbb LJ |
64 | union { |
65 | struct rcu_head rcu; | |
66 | struct list_head list; | |
67 | } u; | |
38516ab5 | 68 | struct tracepoint_func probes[0]; |
19dba33c | 69 | }; |
97e1c18e | 70 | |
19dba33c | 71 | static inline void *allocate_probes(int count) |
97e1c18e | 72 | { |
38516ab5 | 73 | struct tp_probes *p = kmalloc(count * sizeof(struct tracepoint_func) |
19dba33c LJ |
74 | + sizeof(struct tp_probes), GFP_KERNEL); |
75 | return p == NULL ? NULL : p->probes; | |
97e1c18e MD |
76 | } |
77 | ||
19dba33c | 78 | static void rcu_free_old_probes(struct rcu_head *head) |
97e1c18e | 79 | { |
127cafbb | 80 | kfree(container_of(head, struct tp_probes, u.rcu)); |
19dba33c LJ |
81 | } |
82 | ||
38516ab5 | 83 | static inline void release_probes(struct tracepoint_func *old) |
19dba33c LJ |
84 | { |
85 | if (old) { | |
86 | struct tp_probes *tp_probes = container_of(old, | |
87 | struct tp_probes, probes[0]); | |
127cafbb | 88 | call_rcu_sched(&tp_probes->u.rcu, rcu_free_old_probes); |
19dba33c | 89 | } |
97e1c18e MD |
90 | } |
91 | ||
92 | static void debug_print_probes(struct tracepoint_entry *entry) | |
93 | { | |
94 | int i; | |
95 | ||
19dba33c | 96 | if (!tracepoint_debug || !entry->funcs) |
97e1c18e MD |
97 | return; |
98 | ||
38516ab5 SR |
99 | for (i = 0; entry->funcs[i].func; i++) |
100 | printk(KERN_DEBUG "Probe %d : %p\n", i, entry->funcs[i].func); | |
97e1c18e MD |
101 | } |
102 | ||
38516ab5 SR |
103 | static struct tracepoint_func * |
104 | tracepoint_entry_add_probe(struct tracepoint_entry *entry, | |
105 | void *probe, void *data) | |
97e1c18e MD |
106 | { |
107 | int nr_probes = 0; | |
38516ab5 | 108 | struct tracepoint_func *old, *new; |
97e1c18e MD |
109 | |
110 | WARN_ON(!probe); | |
111 | ||
112 | debug_print_probes(entry); | |
113 | old = entry->funcs; | |
114 | if (old) { | |
115 | /* (N -> N+1), (N != 0, 1) probes */ | |
38516ab5 SR |
116 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) |
117 | if (old[nr_probes].func == probe && | |
118 | old[nr_probes].data == data) | |
97e1c18e MD |
119 | return ERR_PTR(-EEXIST); |
120 | } | |
121 | /* + 2 : one for new probe, one for NULL func */ | |
19dba33c | 122 | new = allocate_probes(nr_probes + 2); |
97e1c18e MD |
123 | if (new == NULL) |
124 | return ERR_PTR(-ENOMEM); | |
125 | if (old) | |
38516ab5 SR |
126 | memcpy(new, old, nr_probes * sizeof(struct tracepoint_func)); |
127 | new[nr_probes].func = probe; | |
128 | new[nr_probes].data = data; | |
129 | new[nr_probes + 1].func = NULL; | |
97e1c18e MD |
130 | entry->refcount = nr_probes + 1; |
131 | entry->funcs = new; | |
132 | debug_print_probes(entry); | |
133 | return old; | |
134 | } | |
135 | ||
136 | static void * | |
38516ab5 SR |
137 | tracepoint_entry_remove_probe(struct tracepoint_entry *entry, |
138 | void *probe, void *data) | |
97e1c18e MD |
139 | { |
140 | int nr_probes = 0, nr_del = 0, i; | |
38516ab5 | 141 | struct tracepoint_func *old, *new; |
97e1c18e MD |
142 | |
143 | old = entry->funcs; | |
144 | ||
f66af459 | 145 | if (!old) |
19dba33c | 146 | return ERR_PTR(-ENOENT); |
f66af459 | 147 | |
97e1c18e MD |
148 | debug_print_probes(entry); |
149 | /* (N -> M), (N > 1, M >= 0) probes */ | |
38516ab5 SR |
150 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) { |
151 | if (!probe || | |
152 | (old[nr_probes].func == probe && | |
153 | old[nr_probes].data == data)) | |
97e1c18e MD |
154 | nr_del++; |
155 | } | |
156 | ||
157 | if (nr_probes - nr_del == 0) { | |
158 | /* N -> 0, (N > 1) */ | |
159 | entry->funcs = NULL; | |
160 | entry->refcount = 0; | |
161 | debug_print_probes(entry); | |
162 | return old; | |
163 | } else { | |
164 | int j = 0; | |
165 | /* N -> M, (N > 1, M > 0) */ | |
166 | /* + 1 for NULL */ | |
19dba33c | 167 | new = allocate_probes(nr_probes - nr_del + 1); |
97e1c18e MD |
168 | if (new == NULL) |
169 | return ERR_PTR(-ENOMEM); | |
38516ab5 SR |
170 | for (i = 0; old[i].func; i++) |
171 | if (probe && | |
172 | (old[i].func != probe || old[i].data != data)) | |
97e1c18e | 173 | new[j++] = old[i]; |
38516ab5 | 174 | new[nr_probes - nr_del].func = NULL; |
97e1c18e MD |
175 | entry->refcount = nr_probes - nr_del; |
176 | entry->funcs = new; | |
177 | } | |
178 | debug_print_probes(entry); | |
179 | return old; | |
180 | } | |
181 | ||
182 | /* | |
183 | * Get tracepoint if the tracepoint is present in the tracepoint hash table. | |
184 | * Must be called with tracepoints_mutex held. | |
185 | * Returns NULL if not present. | |
186 | */ | |
187 | static struct tracepoint_entry *get_tracepoint(const char *name) | |
188 | { | |
189 | struct hlist_head *head; | |
190 | struct hlist_node *node; | |
191 | struct tracepoint_entry *e; | |
192 | u32 hash = jhash(name, strlen(name), 0); | |
193 | ||
9795302a | 194 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
97e1c18e MD |
195 | hlist_for_each_entry(e, node, head, hlist) { |
196 | if (!strcmp(name, e->name)) | |
197 | return e; | |
198 | } | |
199 | return NULL; | |
200 | } | |
201 | ||
202 | /* | |
203 | * Add the tracepoint to the tracepoint hash table. Must be called with | |
204 | * tracepoints_mutex held. | |
205 | */ | |
206 | static struct tracepoint_entry *add_tracepoint(const char *name) | |
207 | { | |
208 | struct hlist_head *head; | |
209 | struct hlist_node *node; | |
210 | struct tracepoint_entry *e; | |
211 | size_t name_len = strlen(name) + 1; | |
212 | u32 hash = jhash(name, name_len-1, 0); | |
213 | ||
9795302a | 214 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
97e1c18e MD |
215 | hlist_for_each_entry(e, node, head, hlist) { |
216 | if (!strcmp(name, e->name)) { | |
217 | printk(KERN_NOTICE | |
218 | "tracepoint %s busy\n", name); | |
219 | return ERR_PTR(-EEXIST); /* Already there */ | |
220 | } | |
221 | } | |
222 | /* | |
223 | * Using kmalloc here to allocate a variable length element. Could | |
224 | * cause some memory fragmentation if overused. | |
225 | */ | |
226 | e = kmalloc(sizeof(struct tracepoint_entry) + name_len, GFP_KERNEL); | |
227 | if (!e) | |
228 | return ERR_PTR(-ENOMEM); | |
229 | memcpy(&e->name[0], name, name_len); | |
230 | e->funcs = NULL; | |
231 | e->refcount = 0; | |
97e1c18e MD |
232 | hlist_add_head(&e->hlist, head); |
233 | return e; | |
234 | } | |
235 | ||
236 | /* | |
237 | * Remove the tracepoint from the tracepoint hash table. Must be called with | |
238 | * mutex_lock held. | |
239 | */ | |
19dba33c | 240 | static inline void remove_tracepoint(struct tracepoint_entry *e) |
97e1c18e | 241 | { |
97e1c18e | 242 | hlist_del(&e->hlist); |
97e1c18e | 243 | kfree(e); |
97e1c18e MD |
244 | } |
245 | ||
246 | /* | |
247 | * Sets the probe callback corresponding to one tracepoint. | |
248 | */ | |
249 | static void set_tracepoint(struct tracepoint_entry **entry, | |
250 | struct tracepoint *elem, int active) | |
251 | { | |
252 | WARN_ON(strcmp((*entry)->name, elem->name) != 0); | |
253 | ||
d430d3d7 | 254 | if (elem->regfunc && !jump_label_enabled(&elem->key) && active) |
97419875 | 255 | elem->regfunc(); |
d430d3d7 | 256 | else if (elem->unregfunc && jump_label_enabled(&elem->key) && !active) |
97419875 JS |
257 | elem->unregfunc(); |
258 | ||
97e1c18e MD |
259 | /* |
260 | * rcu_assign_pointer has a smp_wmb() which makes sure that the new | |
261 | * probe callbacks array is consistent before setting a pointer to it. | |
262 | * This array is referenced by __DO_TRACE from | |
263 | * include/linux/tracepoints.h. A matching smp_read_barrier_depends() | |
264 | * is used. | |
265 | */ | |
266 | rcu_assign_pointer(elem->funcs, (*entry)->funcs); | |
d430d3d7 JB |
267 | if (active && !jump_label_enabled(&elem->key)) |
268 | jump_label_inc(&elem->key); | |
269 | else if (!active && jump_label_enabled(&elem->key)) | |
270 | jump_label_dec(&elem->key); | |
97e1c18e MD |
271 | } |
272 | ||
273 | /* | |
274 | * Disable a tracepoint and its probe callback. | |
275 | * Note: only waiting an RCU period after setting elem->call to the empty | |
276 | * function insures that the original callback is not used anymore. This insured | |
277 | * by preempt_disable around the call site. | |
278 | */ | |
279 | static void disable_tracepoint(struct tracepoint *elem) | |
280 | { | |
d430d3d7 | 281 | if (elem->unregfunc && jump_label_enabled(&elem->key)) |
97419875 JS |
282 | elem->unregfunc(); |
283 | ||
d430d3d7 JB |
284 | if (jump_label_enabled(&elem->key)) |
285 | jump_label_dec(&elem->key); | |
de0baf9a | 286 | rcu_assign_pointer(elem->funcs, NULL); |
97e1c18e MD |
287 | } |
288 | ||
289 | /** | |
290 | * tracepoint_update_probe_range - Update a probe range | |
291 | * @begin: beginning of the range | |
292 | * @end: end of the range | |
293 | * | |
294 | * Updates the probe callback corresponding to a range of tracepoints. | |
295 | */ | |
65498646 MD |
296 | void tracepoint_update_probe_range(struct tracepoint * const *begin, |
297 | struct tracepoint * const *end) | |
97e1c18e | 298 | { |
65498646 | 299 | struct tracepoint * const *iter; |
97e1c18e MD |
300 | struct tracepoint_entry *mark_entry; |
301 | ||
ec625cb2 | 302 | if (!begin) |
09933a10 | 303 | return; |
09933a10 | 304 | |
97e1c18e MD |
305 | mutex_lock(&tracepoints_mutex); |
306 | for (iter = begin; iter < end; iter++) { | |
65498646 | 307 | mark_entry = get_tracepoint((*iter)->name); |
97e1c18e | 308 | if (mark_entry) { |
65498646 | 309 | set_tracepoint(&mark_entry, *iter, |
97e1c18e MD |
310 | !!mark_entry->refcount); |
311 | } else { | |
65498646 | 312 | disable_tracepoint(*iter); |
97e1c18e MD |
313 | } |
314 | } | |
315 | mutex_unlock(&tracepoints_mutex); | |
316 | } | |
317 | ||
318 | /* | |
319 | * Update probes, removing the faulty probes. | |
320 | */ | |
321 | static void tracepoint_update_probes(void) | |
322 | { | |
323 | /* Core kernel tracepoints */ | |
65498646 MD |
324 | tracepoint_update_probe_range(__start___tracepoints_ptrs, |
325 | __stop___tracepoints_ptrs); | |
97e1c18e MD |
326 | /* tracepoints in modules. */ |
327 | module_update_tracepoints(); | |
328 | } | |
329 | ||
38516ab5 SR |
330 | static struct tracepoint_func * |
331 | tracepoint_add_probe(const char *name, void *probe, void *data) | |
127cafbb LJ |
332 | { |
333 | struct tracepoint_entry *entry; | |
38516ab5 | 334 | struct tracepoint_func *old; |
127cafbb LJ |
335 | |
336 | entry = get_tracepoint(name); | |
337 | if (!entry) { | |
338 | entry = add_tracepoint(name); | |
339 | if (IS_ERR(entry)) | |
38516ab5 | 340 | return (struct tracepoint_func *)entry; |
127cafbb | 341 | } |
38516ab5 | 342 | old = tracepoint_entry_add_probe(entry, probe, data); |
127cafbb LJ |
343 | if (IS_ERR(old) && !entry->refcount) |
344 | remove_tracepoint(entry); | |
345 | return old; | |
346 | } | |
347 | ||
97e1c18e MD |
348 | /** |
349 | * tracepoint_probe_register - Connect a probe to a tracepoint | |
350 | * @name: tracepoint name | |
351 | * @probe: probe handler | |
352 | * | |
353 | * Returns 0 if ok, error value on error. | |
354 | * The probe address must at least be aligned on the architecture pointer size. | |
355 | */ | |
38516ab5 | 356 | int tracepoint_probe_register(const char *name, void *probe, void *data) |
97e1c18e | 357 | { |
38516ab5 | 358 | struct tracepoint_func *old; |
97e1c18e MD |
359 | |
360 | mutex_lock(&tracepoints_mutex); | |
38516ab5 | 361 | old = tracepoint_add_probe(name, probe, data); |
97e1c18e | 362 | mutex_unlock(&tracepoints_mutex); |
127cafbb LJ |
363 | if (IS_ERR(old)) |
364 | return PTR_ERR(old); | |
365 | ||
97e1c18e | 366 | tracepoint_update_probes(); /* may update entry */ |
19dba33c LJ |
367 | release_probes(old); |
368 | return 0; | |
97e1c18e MD |
369 | } |
370 | EXPORT_SYMBOL_GPL(tracepoint_probe_register); | |
371 | ||
38516ab5 SR |
372 | static struct tracepoint_func * |
373 | tracepoint_remove_probe(const char *name, void *probe, void *data) | |
127cafbb LJ |
374 | { |
375 | struct tracepoint_entry *entry; | |
38516ab5 | 376 | struct tracepoint_func *old; |
127cafbb LJ |
377 | |
378 | entry = get_tracepoint(name); | |
379 | if (!entry) | |
380 | return ERR_PTR(-ENOENT); | |
38516ab5 | 381 | old = tracepoint_entry_remove_probe(entry, probe, data); |
127cafbb LJ |
382 | if (IS_ERR(old)) |
383 | return old; | |
384 | if (!entry->refcount) | |
385 | remove_tracepoint(entry); | |
386 | return old; | |
387 | } | |
388 | ||
97e1c18e MD |
389 | /** |
390 | * tracepoint_probe_unregister - Disconnect a probe from a tracepoint | |
391 | * @name: tracepoint name | |
392 | * @probe: probe function pointer | |
393 | * | |
394 | * We do not need to call a synchronize_sched to make sure the probes have | |
395 | * finished running before doing a module unload, because the module unload | |
396 | * itself uses stop_machine(), which insures that every preempt disabled section | |
397 | * have finished. | |
398 | */ | |
38516ab5 | 399 | int tracepoint_probe_unregister(const char *name, void *probe, void *data) |
97e1c18e | 400 | { |
38516ab5 | 401 | struct tracepoint_func *old; |
97e1c18e MD |
402 | |
403 | mutex_lock(&tracepoints_mutex); | |
38516ab5 | 404 | old = tracepoint_remove_probe(name, probe, data); |
97e1c18e | 405 | mutex_unlock(&tracepoints_mutex); |
127cafbb LJ |
406 | if (IS_ERR(old)) |
407 | return PTR_ERR(old); | |
408 | ||
97e1c18e | 409 | tracepoint_update_probes(); /* may update entry */ |
19dba33c LJ |
410 | release_probes(old); |
411 | return 0; | |
97e1c18e MD |
412 | } |
413 | EXPORT_SYMBOL_GPL(tracepoint_probe_unregister); | |
414 | ||
127cafbb LJ |
415 | static LIST_HEAD(old_probes); |
416 | static int need_update; | |
417 | ||
418 | static void tracepoint_add_old_probes(void *old) | |
419 | { | |
420 | need_update = 1; | |
421 | if (old) { | |
422 | struct tp_probes *tp_probes = container_of(old, | |
423 | struct tp_probes, probes[0]); | |
424 | list_add(&tp_probes->u.list, &old_probes); | |
425 | } | |
426 | } | |
427 | ||
428 | /** | |
429 | * tracepoint_probe_register_noupdate - register a probe but not connect | |
430 | * @name: tracepoint name | |
431 | * @probe: probe handler | |
432 | * | |
433 | * caller must call tracepoint_probe_update_all() | |
434 | */ | |
38516ab5 SR |
435 | int tracepoint_probe_register_noupdate(const char *name, void *probe, |
436 | void *data) | |
127cafbb | 437 | { |
38516ab5 | 438 | struct tracepoint_func *old; |
127cafbb LJ |
439 | |
440 | mutex_lock(&tracepoints_mutex); | |
38516ab5 | 441 | old = tracepoint_add_probe(name, probe, data); |
127cafbb LJ |
442 | if (IS_ERR(old)) { |
443 | mutex_unlock(&tracepoints_mutex); | |
444 | return PTR_ERR(old); | |
445 | } | |
446 | tracepoint_add_old_probes(old); | |
447 | mutex_unlock(&tracepoints_mutex); | |
448 | return 0; | |
449 | } | |
450 | EXPORT_SYMBOL_GPL(tracepoint_probe_register_noupdate); | |
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() | |
458 | */ | |
38516ab5 SR |
459 | int tracepoint_probe_unregister_noupdate(const char *name, void *probe, |
460 | void *data) | |
127cafbb | 461 | { |
38516ab5 | 462 | struct tracepoint_func *old; |
127cafbb LJ |
463 | |
464 | mutex_lock(&tracepoints_mutex); | |
38516ab5 | 465 | old = tracepoint_remove_probe(name, probe, data); |
127cafbb LJ |
466 | if (IS_ERR(old)) { |
467 | mutex_unlock(&tracepoints_mutex); | |
468 | return PTR_ERR(old); | |
469 | } | |
470 | tracepoint_add_old_probes(old); | |
471 | mutex_unlock(&tracepoints_mutex); | |
472 | return 0; | |
473 | } | |
474 | EXPORT_SYMBOL_GPL(tracepoint_probe_unregister_noupdate); | |
475 | ||
476 | /** | |
477 | * tracepoint_probe_update_all - update tracepoints | |
478 | */ | |
479 | void tracepoint_probe_update_all(void) | |
480 | { | |
481 | LIST_HEAD(release_probes); | |
482 | struct tp_probes *pos, *next; | |
483 | ||
484 | mutex_lock(&tracepoints_mutex); | |
485 | if (!need_update) { | |
486 | mutex_unlock(&tracepoints_mutex); | |
487 | return; | |
488 | } | |
489 | if (!list_empty(&old_probes)) | |
490 | list_replace_init(&old_probes, &release_probes); | |
491 | need_update = 0; | |
492 | mutex_unlock(&tracepoints_mutex); | |
493 | ||
494 | tracepoint_update_probes(); | |
495 | list_for_each_entry_safe(pos, next, &release_probes, u.list) { | |
496 | list_del(&pos->u.list); | |
497 | call_rcu_sched(&pos->u.rcu, rcu_free_old_probes); | |
498 | } | |
499 | } | |
500 | EXPORT_SYMBOL_GPL(tracepoint_probe_update_all); | |
501 | ||
97e1c18e MD |
502 | /** |
503 | * tracepoint_get_iter_range - Get a next tracepoint iterator given a range. | |
504 | * @tracepoint: current tracepoints (in), next tracepoint (out) | |
505 | * @begin: beginning of the range | |
506 | * @end: end of the range | |
507 | * | |
508 | * Returns whether a next tracepoint has been found (1) or not (0). | |
509 | * Will return the first tracepoint in the range if the input tracepoint is | |
510 | * NULL. | |
511 | */ | |
65498646 MD |
512 | int tracepoint_get_iter_range(struct tracepoint * const **tracepoint, |
513 | struct tracepoint * const *begin, struct tracepoint * const *end) | |
97e1c18e MD |
514 | { |
515 | if (!*tracepoint && begin != end) { | |
516 | *tracepoint = begin; | |
517 | return 1; | |
518 | } | |
519 | if (*tracepoint >= begin && *tracepoint < end) | |
520 | return 1; | |
521 | return 0; | |
522 | } | |
523 | EXPORT_SYMBOL_GPL(tracepoint_get_iter_range); | |
524 | ||
525 | static void tracepoint_get_iter(struct tracepoint_iter *iter) | |
526 | { | |
527 | int found = 0; | |
528 | ||
529 | /* Core kernel tracepoints */ | |
530 | if (!iter->module) { | |
531 | found = tracepoint_get_iter_range(&iter->tracepoint, | |
65498646 MD |
532 | __start___tracepoints_ptrs, |
533 | __stop___tracepoints_ptrs); | |
97e1c18e MD |
534 | if (found) |
535 | goto end; | |
536 | } | |
537 | /* tracepoints in modules. */ | |
538 | found = module_get_iter_tracepoints(iter); | |
539 | end: | |
540 | if (!found) | |
541 | tracepoint_iter_reset(iter); | |
542 | } | |
543 | ||
544 | void tracepoint_iter_start(struct tracepoint_iter *iter) | |
545 | { | |
546 | tracepoint_get_iter(iter); | |
547 | } | |
548 | EXPORT_SYMBOL_GPL(tracepoint_iter_start); | |
549 | ||
550 | void tracepoint_iter_next(struct tracepoint_iter *iter) | |
551 | { | |
552 | iter->tracepoint++; | |
553 | /* | |
554 | * iter->tracepoint may be invalid because we blindly incremented it. | |
555 | * Make sure it is valid by marshalling on the tracepoints, getting the | |
556 | * tracepoints from following modules if necessary. | |
557 | */ | |
558 | tracepoint_get_iter(iter); | |
559 | } | |
560 | EXPORT_SYMBOL_GPL(tracepoint_iter_next); | |
561 | ||
562 | void tracepoint_iter_stop(struct tracepoint_iter *iter) | |
563 | { | |
564 | } | |
565 | EXPORT_SYMBOL_GPL(tracepoint_iter_stop); | |
566 | ||
567 | void tracepoint_iter_reset(struct tracepoint_iter *iter) | |
568 | { | |
569 | iter->module = NULL; | |
570 | iter->tracepoint = NULL; | |
571 | } | |
572 | EXPORT_SYMBOL_GPL(tracepoint_iter_reset); | |
32f85742 | 573 | |
227a8375 IM |
574 | #ifdef CONFIG_MODULES |
575 | ||
32f85742 MD |
576 | int tracepoint_module_notify(struct notifier_block *self, |
577 | unsigned long val, void *data) | |
578 | { | |
579 | struct module *mod = data; | |
580 | ||
581 | switch (val) { | |
582 | case MODULE_STATE_COMING: | |
32f85742 | 583 | case MODULE_STATE_GOING: |
65498646 MD |
584 | tracepoint_update_probe_range(mod->tracepoints_ptrs, |
585 | mod->tracepoints_ptrs + mod->num_tracepoints); | |
32f85742 MD |
586 | break; |
587 | } | |
588 | return 0; | |
589 | } | |
590 | ||
591 | struct notifier_block tracepoint_module_nb = { | |
592 | .notifier_call = tracepoint_module_notify, | |
593 | .priority = 0, | |
594 | }; | |
595 | ||
596 | static int init_tracepoints(void) | |
597 | { | |
598 | return register_module_notifier(&tracepoint_module_nb); | |
599 | } | |
600 | __initcall(init_tracepoints); | |
227a8375 IM |
601 | |
602 | #endif /* CONFIG_MODULES */ | |
a871bd33 | 603 | |
3d27d8cb | 604 | #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS |
60d970c2 | 605 | |
97419875 | 606 | /* NB: reg/unreg are called while guarded with the tracepoints_mutex */ |
a871bd33 JB |
607 | static int sys_tracepoint_refcount; |
608 | ||
609 | void syscall_regfunc(void) | |
610 | { | |
611 | unsigned long flags; | |
612 | struct task_struct *g, *t; | |
613 | ||
a871bd33 JB |
614 | if (!sys_tracepoint_refcount) { |
615 | read_lock_irqsave(&tasklist_lock, flags); | |
616 | do_each_thread(g, t) { | |
cc3b13c1 HB |
617 | /* Skip kernel threads. */ |
618 | if (t->mm) | |
619 | set_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT); | |
a871bd33 JB |
620 | } while_each_thread(g, t); |
621 | read_unlock_irqrestore(&tasklist_lock, flags); | |
622 | } | |
623 | sys_tracepoint_refcount++; | |
a871bd33 JB |
624 | } |
625 | ||
626 | void syscall_unregfunc(void) | |
627 | { | |
628 | unsigned long flags; | |
629 | struct task_struct *g, *t; | |
630 | ||
a871bd33 JB |
631 | sys_tracepoint_refcount--; |
632 | if (!sys_tracepoint_refcount) { | |
633 | read_lock_irqsave(&tasklist_lock, flags); | |
634 | do_each_thread(g, t) { | |
66700001 | 635 | clear_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT); |
a871bd33 JB |
636 | } while_each_thread(g, t); |
637 | read_unlock_irqrestore(&tasklist_lock, flags); | |
638 | } | |
a871bd33 | 639 | } |
60d970c2 | 640 | #endif |