Blame view
kernel/tracepoint.c
19.6 KB
97e1c18e8
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 |
/* * Copyright (C) 2008 Mathieu Desnoyers * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include <linux/module.h> #include <linux/mutex.h> #include <linux/types.h> #include <linux/jhash.h> #include <linux/list.h> #include <linux/rcupdate.h> #include <linux/tracepoint.h> #include <linux/err.h> #include <linux/slab.h> |
a871bd33a
|
27 |
#include <linux/sched.h> |
8f7b50c51
|
28 |
#include <linux/jump_label.h> |
97e1c18e8
|
29 |
|
654986462
|
30 31 |
extern struct tracepoint * const __start___tracepoints_ptrs[]; extern struct tracepoint * const __stop___tracepoints_ptrs[]; |
97e1c18e8
|
32 33 34 35 36 |
/* Set to 1 to enable tracepoint debug output */ static const int tracepoint_debug; /* |
b75ef8b44
|
37 38 |
* Tracepoints mutex protects the builtin and module tracepoints and the hash * table, as well as the local module list. |
97e1c18e8
|
39 40 |
*/ static DEFINE_MUTEX(tracepoints_mutex); |
b75ef8b44
|
41 42 43 44 |
#ifdef CONFIG_MODULES /* Local list of struct module */ static LIST_HEAD(tracepoint_module_list); #endif /* CONFIG_MODULES */ |
97e1c18e8
|
45 46 47 48 49 50 |
/* * Tracepoint hash table, containing the active tracepoints. * Protected by tracepoints_mutex. */ #define TRACEPOINT_HASH_BITS 6 #define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS) |
19dba33c4
|
51 |
static struct hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE]; |
97e1c18e8
|
52 53 54 |
/* * Note about RCU : |
fd589a8f0
|
55 |
* It is used to delay the free of multiple probes array until a quiescent |
97e1c18e8
|
56 57 58 59 60 |
* state is reached. * Tracepoint entries modifications are protected by the tracepoints_mutex. */ struct tracepoint_entry { struct hlist_node hlist; |
38516ab59
|
61 |
struct tracepoint_func *funcs; |
97e1c18e8
|
62 |
int refcount; /* Number of times armed. 0 if disarmed. */ |
97e1c18e8
|
63 64 |
char name[0]; }; |
19dba33c4
|
65 |
struct tp_probes { |
127cafbb2
|
66 67 68 69 |
union { struct rcu_head rcu; struct list_head list; } u; |
38516ab59
|
70 |
struct tracepoint_func probes[0]; |
19dba33c4
|
71 |
}; |
97e1c18e8
|
72 |
|
19dba33c4
|
73 |
static inline void *allocate_probes(int count) |
97e1c18e8
|
74 |
{ |
38516ab59
|
75 |
struct tp_probes *p = kmalloc(count * sizeof(struct tracepoint_func) |
19dba33c4
|
76 77 |
+ sizeof(struct tp_probes), GFP_KERNEL); return p == NULL ? NULL : p->probes; |
97e1c18e8
|
78 |
} |
19dba33c4
|
79 |
static void rcu_free_old_probes(struct rcu_head *head) |
97e1c18e8
|
80 |
{ |
127cafbb2
|
81 |
kfree(container_of(head, struct tp_probes, u.rcu)); |
19dba33c4
|
82 |
} |
38516ab59
|
83 |
static inline void release_probes(struct tracepoint_func *old) |
19dba33c4
|
84 85 86 87 |
{ if (old) { struct tp_probes *tp_probes = container_of(old, struct tp_probes, probes[0]); |
127cafbb2
|
88 |
call_rcu_sched(&tp_probes->u.rcu, rcu_free_old_probes); |
19dba33c4
|
89 |
} |
97e1c18e8
|
90 91 92 93 94 |
} static void debug_print_probes(struct tracepoint_entry *entry) { int i; |
19dba33c4
|
95 |
if (!tracepoint_debug || !entry->funcs) |
97e1c18e8
|
96 |
return; |
38516ab59
|
97 98 99 |
for (i = 0; entry->funcs[i].func; i++) printk(KERN_DEBUG "Probe %d : %p ", i, entry->funcs[i].func); |
97e1c18e8
|
100 |
} |
38516ab59
|
101 102 103 |
static struct tracepoint_func * tracepoint_entry_add_probe(struct tracepoint_entry *entry, void *probe, void *data) |
97e1c18e8
|
104 105 |
{ int nr_probes = 0; |
38516ab59
|
106 |
struct tracepoint_func *old, *new; |
97e1c18e8
|
107 108 109 110 111 112 113 |
WARN_ON(!probe); debug_print_probes(entry); old = entry->funcs; if (old) { /* (N -> N+1), (N != 0, 1) probes */ |
38516ab59
|
114 115 116 |
for (nr_probes = 0; old[nr_probes].func; nr_probes++) if (old[nr_probes].func == probe && old[nr_probes].data == data) |
97e1c18e8
|
117 118 119 |
return ERR_PTR(-EEXIST); } /* + 2 : one for new probe, one for NULL func */ |
19dba33c4
|
120 |
new = allocate_probes(nr_probes + 2); |
97e1c18e8
|
121 122 123 |
if (new == NULL) return ERR_PTR(-ENOMEM); if (old) |
38516ab59
|
124 125 126 127 |
memcpy(new, old, nr_probes * sizeof(struct tracepoint_func)); new[nr_probes].func = probe; new[nr_probes].data = data; new[nr_probes + 1].func = NULL; |
97e1c18e8
|
128 129 130 131 132 133 134 |
entry->refcount = nr_probes + 1; entry->funcs = new; debug_print_probes(entry); return old; } static void * |
38516ab59
|
135 136 |
tracepoint_entry_remove_probe(struct tracepoint_entry *entry, void *probe, void *data) |
97e1c18e8
|
137 138 |
{ int nr_probes = 0, nr_del = 0, i; |
38516ab59
|
139 |
struct tracepoint_func *old, *new; |
97e1c18e8
|
140 141 |
old = entry->funcs; |
f66af459a
|
142 |
if (!old) |
19dba33c4
|
143 |
return ERR_PTR(-ENOENT); |
f66af459a
|
144 |
|
97e1c18e8
|
145 146 |
debug_print_probes(entry); /* (N -> M), (N > 1, M >= 0) probes */ |
38516ab59
|
147 148 149 150 |
for (nr_probes = 0; old[nr_probes].func; nr_probes++) { if (!probe || (old[nr_probes].func == probe && old[nr_probes].data == data)) |
97e1c18e8
|
151 152 153 154 155 156 157 158 159 160 161 162 163 |
nr_del++; } if (nr_probes - nr_del == 0) { /* N -> 0, (N > 1) */ entry->funcs = NULL; entry->refcount = 0; debug_print_probes(entry); return old; } else { int j = 0; /* N -> M, (N > 1, M > 0) */ /* + 1 for NULL */ |
19dba33c4
|
164 |
new = allocate_probes(nr_probes - nr_del + 1); |
97e1c18e8
|
165 166 |
if (new == NULL) return ERR_PTR(-ENOMEM); |
38516ab59
|
167 168 169 |
for (i = 0; old[i].func; i++) if (probe && (old[i].func != probe || old[i].data != data)) |
97e1c18e8
|
170 |
new[j++] = old[i]; |
38516ab59
|
171 |
new[nr_probes - nr_del].func = NULL; |
97e1c18e8
|
172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 |
entry->refcount = nr_probes - nr_del; entry->funcs = new; } debug_print_probes(entry); return old; } /* * Get tracepoint if the tracepoint is present in the tracepoint hash table. * Must be called with tracepoints_mutex held. * Returns NULL if not present. */ static struct tracepoint_entry *get_tracepoint(const char *name) { struct hlist_head *head; struct hlist_node *node; struct tracepoint_entry *e; u32 hash = jhash(name, strlen(name), 0); |
9795302ac
|
190 |
head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
97e1c18e8
|
191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 |
hlist_for_each_entry(e, node, head, hlist) { if (!strcmp(name, e->name)) return e; } return NULL; } /* * Add the tracepoint to the tracepoint hash table. Must be called with * tracepoints_mutex held. */ static struct tracepoint_entry *add_tracepoint(const char *name) { struct hlist_head *head; struct hlist_node *node; struct tracepoint_entry *e; size_t name_len = strlen(name) + 1; u32 hash = jhash(name, name_len-1, 0); |
9795302ac
|
209 |
head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
97e1c18e8
|
210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 |
hlist_for_each_entry(e, node, head, hlist) { if (!strcmp(name, e->name)) { printk(KERN_NOTICE "tracepoint %s busy ", name); return ERR_PTR(-EEXIST); /* Already there */ } } /* * Using kmalloc here to allocate a variable length element. Could * cause some memory fragmentation if overused. */ e = kmalloc(sizeof(struct tracepoint_entry) + name_len, GFP_KERNEL); if (!e) return ERR_PTR(-ENOMEM); memcpy(&e->name[0], name, name_len); e->funcs = NULL; e->refcount = 0; |
97e1c18e8
|
228 229 230 231 232 233 234 235 |
hlist_add_head(&e->hlist, head); return e; } /* * Remove the tracepoint from the tracepoint hash table. Must be called with * mutex_lock held. */ |
19dba33c4
|
236 |
static inline void remove_tracepoint(struct tracepoint_entry *e) |
97e1c18e8
|
237 |
{ |
97e1c18e8
|
238 |
hlist_del(&e->hlist); |
97e1c18e8
|
239 |
kfree(e); |
97e1c18e8
|
240 241 242 243 244 245 246 247 248 |
} /* * Sets the probe callback corresponding to one tracepoint. */ static void set_tracepoint(struct tracepoint_entry **entry, struct tracepoint *elem, int active) { WARN_ON(strcmp((*entry)->name, elem->name) != 0); |
d430d3d7e
|
249 |
if (elem->regfunc && !jump_label_enabled(&elem->key) && active) |
974198758
|
250 |
elem->regfunc(); |
d430d3d7e
|
251 |
else if (elem->unregfunc && jump_label_enabled(&elem->key) && !active) |
974198758
|
252 |
elem->unregfunc(); |
97e1c18e8
|
253 254 255 256 257 258 259 260 |
/* * rcu_assign_pointer has a smp_wmb() which makes sure that the new * probe callbacks array is consistent before setting a pointer to it. * This array is referenced by __DO_TRACE from * include/linux/tracepoints.h. A matching smp_read_barrier_depends() * is used. */ rcu_assign_pointer(elem->funcs, (*entry)->funcs); |
d430d3d7e
|
261 262 263 264 |
if (active && !jump_label_enabled(&elem->key)) jump_label_inc(&elem->key); else if (!active && jump_label_enabled(&elem->key)) jump_label_dec(&elem->key); |
97e1c18e8
|
265 266 267 268 269 270 271 272 273 274 |
} /* * Disable a tracepoint and its probe callback. * Note: only waiting an RCU period after setting elem->call to the empty * function insures that the original callback is not used anymore. This insured * by preempt_disable around the call site. */ static void disable_tracepoint(struct tracepoint *elem) { |
d430d3d7e
|
275 |
if (elem->unregfunc && jump_label_enabled(&elem->key)) |
974198758
|
276 |
elem->unregfunc(); |
d430d3d7e
|
277 278 |
if (jump_label_enabled(&elem->key)) jump_label_dec(&elem->key); |
de0baf9ad
|
279 |
rcu_assign_pointer(elem->funcs, NULL); |
97e1c18e8
|
280 281 282 283 284 285 286 287 |
} /** * tracepoint_update_probe_range - Update a probe range * @begin: beginning of the range * @end: end of the range * * Updates the probe callback corresponding to a range of tracepoints. |
b75ef8b44
|
288 |
* Called with tracepoints_mutex held. |
97e1c18e8
|
289 |
*/ |
b75ef8b44
|
290 291 |
static void tracepoint_update_probe_range(struct tracepoint * const *begin, struct tracepoint * const *end) |
97e1c18e8
|
292 |
{ |
654986462
|
293 |
struct tracepoint * const *iter; |
97e1c18e8
|
294 |
struct tracepoint_entry *mark_entry; |
ec625cb29
|
295 |
if (!begin) |
09933a108
|
296 |
return; |
09933a108
|
297 |
|
97e1c18e8
|
298 |
for (iter = begin; iter < end; iter++) { |
654986462
|
299 |
mark_entry = get_tracepoint((*iter)->name); |
97e1c18e8
|
300 |
if (mark_entry) { |
654986462
|
301 |
set_tracepoint(&mark_entry, *iter, |
97e1c18e8
|
302 303 |
!!mark_entry->refcount); } else { |
654986462
|
304 |
disable_tracepoint(*iter); |
97e1c18e8
|
305 306 |
} } |
97e1c18e8
|
307 |
} |
b75ef8b44
|
308 309 310 311 312 313 314 315 316 317 318 319 320 321 |
#ifdef CONFIG_MODULES void module_update_tracepoints(void) { struct tp_module *tp_mod; list_for_each_entry(tp_mod, &tracepoint_module_list, list) tracepoint_update_probe_range(tp_mod->tracepoints_ptrs, tp_mod->tracepoints_ptrs + tp_mod->num_tracepoints); } #else /* CONFIG_MODULES */ void module_update_tracepoints(void) { } #endif /* CONFIG_MODULES */ |
97e1c18e8
|
322 323 |
/* * Update probes, removing the faulty probes. |
b75ef8b44
|
324 |
* Called with tracepoints_mutex held. |
97e1c18e8
|
325 326 327 328 |
*/ static void tracepoint_update_probes(void) { /* Core kernel tracepoints */ |
654986462
|
329 330 |
tracepoint_update_probe_range(__start___tracepoints_ptrs, __stop___tracepoints_ptrs); |
97e1c18e8
|
331 332 333 |
/* tracepoints in modules. */ module_update_tracepoints(); } |
38516ab59
|
334 335 |
static struct tracepoint_func * tracepoint_add_probe(const char *name, void *probe, void *data) |
127cafbb2
|
336 337 |
{ struct tracepoint_entry *entry; |
38516ab59
|
338 |
struct tracepoint_func *old; |
127cafbb2
|
339 340 341 342 343 |
entry = get_tracepoint(name); if (!entry) { entry = add_tracepoint(name); if (IS_ERR(entry)) |
38516ab59
|
344 |
return (struct tracepoint_func *)entry; |
127cafbb2
|
345 |
} |
38516ab59
|
346 |
old = tracepoint_entry_add_probe(entry, probe, data); |
127cafbb2
|
347 348 349 350 |
if (IS_ERR(old) && !entry->refcount) remove_tracepoint(entry); return old; } |
97e1c18e8
|
351 352 353 354 355 356 357 358 |
/** * tracepoint_probe_register - Connect a probe to a tracepoint * @name: tracepoint name * @probe: probe handler * * Returns 0 if ok, error value on error. * The probe address must at least be aligned on the architecture pointer size. */ |
38516ab59
|
359 |
int tracepoint_probe_register(const char *name, void *probe, void *data) |
97e1c18e8
|
360 |
{ |
38516ab59
|
361 |
struct tracepoint_func *old; |
97e1c18e8
|
362 363 |
mutex_lock(&tracepoints_mutex); |
38516ab59
|
364 |
old = tracepoint_add_probe(name, probe, data); |
b75ef8b44
|
365 366 |
if (IS_ERR(old)) { mutex_unlock(&tracepoints_mutex); |
127cafbb2
|
367 |
return PTR_ERR(old); |
b75ef8b44
|
368 |
} |
97e1c18e8
|
369 |
tracepoint_update_probes(); /* may update entry */ |
b75ef8b44
|
370 |
mutex_unlock(&tracepoints_mutex); |
19dba33c4
|
371 372 |
release_probes(old); return 0; |
97e1c18e8
|
373 374 |
} EXPORT_SYMBOL_GPL(tracepoint_probe_register); |
38516ab59
|
375 376 |
static struct tracepoint_func * tracepoint_remove_probe(const char *name, void *probe, void *data) |
127cafbb2
|
377 378 |
{ struct tracepoint_entry *entry; |
38516ab59
|
379 |
struct tracepoint_func *old; |
127cafbb2
|
380 381 382 383 |
entry = get_tracepoint(name); if (!entry) return ERR_PTR(-ENOENT); |
38516ab59
|
384 |
old = tracepoint_entry_remove_probe(entry, probe, data); |
127cafbb2
|
385 386 387 388 389 390 |
if (IS_ERR(old)) return old; if (!entry->refcount) remove_tracepoint(entry); return old; } |
97e1c18e8
|
391 392 393 394 395 396 397 398 399 400 |
/** * tracepoint_probe_unregister - Disconnect a probe from a tracepoint * @name: tracepoint name * @probe: probe function pointer * * We do not need to call a synchronize_sched to make sure the probes have * finished running before doing a module unload, because the module unload * itself uses stop_machine(), which insures that every preempt disabled section * have finished. */ |
38516ab59
|
401 |
int tracepoint_probe_unregister(const char *name, void *probe, void *data) |
97e1c18e8
|
402 |
{ |
38516ab59
|
403 |
struct tracepoint_func *old; |
97e1c18e8
|
404 405 |
mutex_lock(&tracepoints_mutex); |
38516ab59
|
406 |
old = tracepoint_remove_probe(name, probe, data); |
b75ef8b44
|
407 408 |
if (IS_ERR(old)) { mutex_unlock(&tracepoints_mutex); |
127cafbb2
|
409 |
return PTR_ERR(old); |
b75ef8b44
|
410 |
} |
97e1c18e8
|
411 |
tracepoint_update_probes(); /* may update entry */ |
b75ef8b44
|
412 |
mutex_unlock(&tracepoints_mutex); |
19dba33c4
|
413 414 |
release_probes(old); return 0; |
97e1c18e8
|
415 416 |
} EXPORT_SYMBOL_GPL(tracepoint_probe_unregister); |
127cafbb2
|
417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 |
static LIST_HEAD(old_probes); static int need_update; static void tracepoint_add_old_probes(void *old) { need_update = 1; if (old) { struct tp_probes *tp_probes = container_of(old, struct tp_probes, probes[0]); list_add(&tp_probes->u.list, &old_probes); } } /** * tracepoint_probe_register_noupdate - register a probe but not connect * @name: tracepoint name * @probe: probe handler * * caller must call tracepoint_probe_update_all() */ |
38516ab59
|
437 438 |
int tracepoint_probe_register_noupdate(const char *name, void *probe, void *data) |
127cafbb2
|
439 |
{ |
38516ab59
|
440 |
struct tracepoint_func *old; |
127cafbb2
|
441 442 |
mutex_lock(&tracepoints_mutex); |
38516ab59
|
443 |
old = tracepoint_add_probe(name, probe, data); |
127cafbb2
|
444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 |
if (IS_ERR(old)) { mutex_unlock(&tracepoints_mutex); return PTR_ERR(old); } tracepoint_add_old_probes(old); mutex_unlock(&tracepoints_mutex); return 0; } EXPORT_SYMBOL_GPL(tracepoint_probe_register_noupdate); /** * tracepoint_probe_unregister_noupdate - remove a probe but not disconnect * @name: tracepoint name * @probe: probe function pointer * * caller must call tracepoint_probe_update_all() */ |
38516ab59
|
461 462 |
int tracepoint_probe_unregister_noupdate(const char *name, void *probe, void *data) |
127cafbb2
|
463 |
{ |
38516ab59
|
464 |
struct tracepoint_func *old; |
127cafbb2
|
465 466 |
mutex_lock(&tracepoints_mutex); |
38516ab59
|
467 |
old = tracepoint_remove_probe(name, probe, data); |
127cafbb2
|
468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 |
if (IS_ERR(old)) { mutex_unlock(&tracepoints_mutex); return PTR_ERR(old); } tracepoint_add_old_probes(old); mutex_unlock(&tracepoints_mutex); return 0; } EXPORT_SYMBOL_GPL(tracepoint_probe_unregister_noupdate); /** * tracepoint_probe_update_all - update tracepoints */ void tracepoint_probe_update_all(void) { LIST_HEAD(release_probes); struct tp_probes *pos, *next; mutex_lock(&tracepoints_mutex); if (!need_update) { mutex_unlock(&tracepoints_mutex); return; } if (!list_empty(&old_probes)) list_replace_init(&old_probes, &release_probes); need_update = 0; |
127cafbb2
|
494 |
tracepoint_update_probes(); |
b75ef8b44
|
495 |
mutex_unlock(&tracepoints_mutex); |
127cafbb2
|
496 497 498 499 500 501 |
list_for_each_entry_safe(pos, next, &release_probes, u.list) { list_del(&pos->u.list); call_rcu_sched(&pos->u.rcu, rcu_free_old_probes); } } EXPORT_SYMBOL_GPL(tracepoint_probe_update_all); |
97e1c18e8
|
502 503 504 505 506 507 508 509 510 511 |
/** * tracepoint_get_iter_range - Get a next tracepoint iterator given a range. * @tracepoint: current tracepoints (in), next tracepoint (out) * @begin: beginning of the range * @end: end of the range * * Returns whether a next tracepoint has been found (1) or not (0). * Will return the first tracepoint in the range if the input tracepoint is * NULL. */ |
b75ef8b44
|
512 |
static int tracepoint_get_iter_range(struct tracepoint * const **tracepoint, |
654986462
|
513 |
struct tracepoint * const *begin, struct tracepoint * const *end) |
97e1c18e8
|
514 515 516 517 518 519 520 521 522 |
{ if (!*tracepoint && begin != end) { *tracepoint = begin; return 1; } if (*tracepoint >= begin && *tracepoint < end) return 1; return 0; } |
97e1c18e8
|
523 |
|
b75ef8b44
|
524 |
#ifdef CONFIG_MODULES |
97e1c18e8
|
525 526 527 |
static void tracepoint_get_iter(struct tracepoint_iter *iter) { int found = 0; |
b75ef8b44
|
528 |
struct tp_module *iter_mod; |
97e1c18e8
|
529 530 531 532 |
/* Core kernel tracepoints */ if (!iter->module) { found = tracepoint_get_iter_range(&iter->tracepoint, |
654986462
|
533 534 |
__start___tracepoints_ptrs, __stop___tracepoints_ptrs); |
97e1c18e8
|
535 536 537 |
if (found) goto end; } |
b75ef8b44
|
538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 |
/* Tracepoints in modules */ mutex_lock(&tracepoints_mutex); list_for_each_entry(iter_mod, &tracepoint_module_list, list) { /* * Sorted module list */ if (iter_mod < iter->module) continue; else if (iter_mod > iter->module) iter->tracepoint = NULL; found = tracepoint_get_iter_range(&iter->tracepoint, iter_mod->tracepoints_ptrs, iter_mod->tracepoints_ptrs + iter_mod->num_tracepoints); if (found) { iter->module = iter_mod; break; } } mutex_unlock(&tracepoints_mutex); |
97e1c18e8
|
558 559 560 561 |
end: if (!found) tracepoint_iter_reset(iter); } |
b75ef8b44
|
562 563 564 565 566 567 568 569 570 571 572 573 574 |
#else /* CONFIG_MODULES */ static void tracepoint_get_iter(struct tracepoint_iter *iter) { int found = 0; /* Core kernel tracepoints */ found = tracepoint_get_iter_range(&iter->tracepoint, __start___tracepoints_ptrs, __stop___tracepoints_ptrs); if (!found) tracepoint_iter_reset(iter); } #endif /* CONFIG_MODULES */ |
97e1c18e8
|
575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 |
void tracepoint_iter_start(struct tracepoint_iter *iter) { tracepoint_get_iter(iter); } EXPORT_SYMBOL_GPL(tracepoint_iter_start); void tracepoint_iter_next(struct tracepoint_iter *iter) { iter->tracepoint++; /* * iter->tracepoint may be invalid because we blindly incremented it. * Make sure it is valid by marshalling on the tracepoints, getting the * tracepoints from following modules if necessary. */ tracepoint_get_iter(iter); } EXPORT_SYMBOL_GPL(tracepoint_iter_next); void tracepoint_iter_stop(struct tracepoint_iter *iter) { } EXPORT_SYMBOL_GPL(tracepoint_iter_stop); void tracepoint_iter_reset(struct tracepoint_iter *iter) { |
b75ef8b44
|
601 |
#ifdef CONFIG_MODULES |
97e1c18e8
|
602 |
iter->module = NULL; |
b75ef8b44
|
603 |
#endif /* CONFIG_MODULES */ |
97e1c18e8
|
604 605 606 |
iter->tracepoint = NULL; } EXPORT_SYMBOL_GPL(tracepoint_iter_reset); |
32f857427
|
607 |
|
227a83756
|
608 |
#ifdef CONFIG_MODULES |
b75ef8b44
|
609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 |
static int tracepoint_module_coming(struct module *mod) { struct tp_module *tp_mod, *iter; int ret = 0; /* * We skip modules that tain the kernel, especially those with different * module header (for forced load), to make sure we don't cause a crash. */ if (mod->taints) return 0; mutex_lock(&tracepoints_mutex); tp_mod = kmalloc(sizeof(struct tp_module), GFP_KERNEL); if (!tp_mod) { ret = -ENOMEM; goto end; } tp_mod->num_tracepoints = mod->num_tracepoints; tp_mod->tracepoints_ptrs = mod->tracepoints_ptrs; /* * tracepoint_module_list is kept sorted by struct module pointer * address for iteration on tracepoints from a seq_file that can release * the mutex between calls. */ list_for_each_entry_reverse(iter, &tracepoint_module_list, list) { BUG_ON(iter == tp_mod); /* Should never be in the list twice */ if (iter < tp_mod) { /* We belong to the location right after iter. */ list_add(&tp_mod->list, &iter->list); goto module_added; } } /* We belong to the beginning of the list */ list_add(&tp_mod->list, &tracepoint_module_list); module_added: tracepoint_update_probe_range(mod->tracepoints_ptrs, mod->tracepoints_ptrs + mod->num_tracepoints); end: mutex_unlock(&tracepoints_mutex); return ret; } static int tracepoint_module_going(struct module *mod) { struct tp_module *pos; mutex_lock(&tracepoints_mutex); tracepoint_update_probe_range(mod->tracepoints_ptrs, mod->tracepoints_ptrs + mod->num_tracepoints); list_for_each_entry(pos, &tracepoint_module_list, list) { if (pos->tracepoints_ptrs == mod->tracepoints_ptrs) { list_del(&pos->list); kfree(pos); break; } } /* * In the case of modules that were tainted at "coming", we'll simply * walk through the list without finding it. We cannot use the "tainted" * flag on "going", in case a module taints the kernel only after being * loaded. */ mutex_unlock(&tracepoints_mutex); return 0; } |
227a83756
|
675 |
|
32f857427
|
676 677 678 679 |
int tracepoint_module_notify(struct notifier_block *self, unsigned long val, void *data) { struct module *mod = data; |
b75ef8b44
|
680 |
int ret = 0; |
32f857427
|
681 682 683 |
switch (val) { case MODULE_STATE_COMING: |
b75ef8b44
|
684 685 686 687 |
ret = tracepoint_module_coming(mod); break; case MODULE_STATE_LIVE: break; |
32f857427
|
688 |
case MODULE_STATE_GOING: |
b75ef8b44
|
689 |
ret = tracepoint_module_going(mod); |
32f857427
|
690 691 |
break; } |
b75ef8b44
|
692 |
return ret; |
32f857427
|
693 694 695 696 697 698 699 700 701 702 703 704 |
} struct notifier_block tracepoint_module_nb = { .notifier_call = tracepoint_module_notify, .priority = 0, }; static int init_tracepoints(void) { return register_module_notifier(&tracepoint_module_nb); } __initcall(init_tracepoints); |
227a83756
|
705 |
#endif /* CONFIG_MODULES */ |
a871bd33a
|
706 |
|
3d27d8cb3
|
707 |
#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS |
60d970c25
|
708 |
|
974198758
|
709 |
/* NB: reg/unreg are called while guarded with the tracepoints_mutex */ |
a871bd33a
|
710 711 712 713 714 715 |
static int sys_tracepoint_refcount; void syscall_regfunc(void) { unsigned long flags; struct task_struct *g, *t; |
a871bd33a
|
716 717 718 |
if (!sys_tracepoint_refcount) { read_lock_irqsave(&tasklist_lock, flags); do_each_thread(g, t) { |
cc3b13c11
|
719 720 721 |
/* Skip kernel threads. */ if (t->mm) set_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT); |
a871bd33a
|
722 723 724 725 |
} while_each_thread(g, t); read_unlock_irqrestore(&tasklist_lock, flags); } sys_tracepoint_refcount++; |
a871bd33a
|
726 727 728 729 730 731 |
} void syscall_unregfunc(void) { unsigned long flags; struct task_struct *g, *t; |
a871bd33a
|
732 733 734 735 |
sys_tracepoint_refcount--; if (!sys_tracepoint_refcount) { read_lock_irqsave(&tasklist_lock, flags); do_each_thread(g, t) { |
667000011
|
736 |
clear_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT); |
a871bd33a
|
737 738 739 |
} while_each_thread(g, t); read_unlock_irqrestore(&tasklist_lock, flags); } |
a871bd33a
|
740 |
} |
60d970c25
|
741 |
#endif |