libust/tracepoint.c

   1 /*
   2  * Copyright (C) 2008 Mathieu Desnoyers
   3  * Copyright (C) 2009 Pierre-Marc Fournier
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; either version 2
   8  * of the License, or (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  18  *
  19  * Ported to userspace by Pierre-Marc Fournier.
  20  */
  21
  22 //ust// #include <linux/module.h>
  23 //ust// #include <linux/mutex.h>
  24 //ust// #include <linux/types.h>
  25 //ust// #include <linux/jhash.h>
  26 //ust// #include <linux/list.h>
  27 //ust// #include <linux/rcupdate.h>
  28 //ust// #include <linux/tracepoint.h>
  29 //ust// #include <linux/err.h>
  30 //ust// #include <linux/slab.h>
  31 //ust// #include <linux/immediate.h>
  32
  33 #include <errno.h>
  34
  35 #include "kernelcompat.h"
  36 #include "tracepoint.h"
  37 #include "usterr.h"
  38 #include "list.h"
  39 #include "urcu.h"
  40
  41 //extern struct tracepoint __start___tracepoints[] __attribute__((visibility("hidden")));
  42 //extern struct tracepoint __stop___tracepoints[] __attribute__((visibility("hidden")));
  43
  44 /* Set to 1 to enable tracepoint debug output */
  45 static const int tracepoint_debug;
  46
  47 /* libraries that contain tracepoints (struct tracepoint_lib) */
  48 static LIST_HEAD(libs);
  49
  50 /*
  51  * tracepoints_mutex nests inside module_mutex. Tracepoints mutex protects the
  52  * builtin and module tracepoints and the hash table.
  53  */
  54 static DEFINE_MUTEX(tracepoints_mutex);
  55
  56 /*
  57  * Tracepoint hash table, containing the active tracepoints.
  58  * Protected by tracepoints_mutex.
  59  */
  60 #define TRACEPOINT_HASH_BITS 6
  61 #define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS)
  62 static struct hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE];
  63
  64 /*
  65  * Note about RCU :
  66  * It is used to to delay the free of multiple probes array until a quiescent
  67  * state is reached.
  68  * Tracepoint entries modifications are protected by the tracepoints_mutex.
  69  */
  70 struct tracepoint_entry {
  71         struct hlist_node hlist;
  72         void **funcs;
  73         int refcount;   /* Number of times armed. 0 if disarmed. */
  74         char name[0];
  75 };
  76
  77 struct tp_probes {
  78         union {
  79 //ust//         struct rcu_head rcu;
  80                 struct list_head list;
  81         } u;
  82         void *probes[0];
  83 };
  84
  85 static inline void *allocate_probes(int count)
  86 {
  87         struct tp_probes *p  = kmalloc(count * sizeof(void *)
  88                         + sizeof(struct tp_probes), GFP_KERNEL);
  89         return p == NULL ? NULL : p->probes;
  90 }
  91
  92 //ust// static void rcu_free_old_probes(struct rcu_head *head)
  93 //ust// {
  94 //ust//         kfree(container_of(head, struct tp_probes, u.rcu));
  95 //ust// }
  96
  97 static inline void release_probes(void *old)
  98 {
  99         if (old) {
 100                 struct tp_probes *tp_probes = container_of(old,
 101                         struct tp_probes, probes[0]);
 102 //ust//         call_rcu_sched(&tp_probes->u.rcu, rcu_free_old_probes);
 103                 synchronize_rcu();
 104                 kfree(tp_probes);
 105         }
 106 }
 107
 108 static void debug_print_probes(struct tracepoint_entry *entry)
 109 {
 110         int i;
 111
 112         if (!tracepoint_debug || !entry->funcs)
 113                 return;
 114
 115         for (i = 0; entry->funcs[i]; i++)
 116                 printk(KERN_DEBUG "Probe %d : %p\n", i, entry->funcs[i]);
 117 }
 118
 119 static void *
 120 tracepoint_entry_add_probe(struct tracepoint_entry *entry, void *probe)
 121 {
 122         int nr_probes = 0;
 123         void **old, **new;
 124
 125         WARN_ON(!probe);
 126
 127         debug_print_probes(entry);
 128         old = entry->funcs;
 129         if (old) {
 130                 /* (N -> N+1), (N != 0, 1) probes */
 131                 for (nr_probes = 0; old[nr_probes]; nr_probes++)
 132                         if (old[nr_probes] == probe)
 133                                 return ERR_PTR(-EEXIST);
 134         }
 135         /* + 2 : one for new probe, one for NULL func */
 136         new = allocate_probes(nr_probes + 2);
 137         if (new == NULL)
 138                 return ERR_PTR(-ENOMEM);
 139         if (old)
 140                 memcpy(new, old, nr_probes * sizeof(void *));
 141         new[nr_probes] = probe;
 142         new[nr_probes + 1] = NULL;
 143         entry->refcount = nr_probes + 1;
 144         entry->funcs = new;
 145         debug_print_probes(entry);
 146         return old;
 147 }
 148
 149 static void *
 150 tracepoint_entry_remove_probe(struct tracepoint_entry *entry, void *probe)
 151 {
 152         int nr_probes = 0, nr_del = 0, i;
 153         void **old, **new;
 154
 155         old = entry->funcs;
 156
 157         if (!old)
 158                 return ERR_PTR(-ENOENT);
 159
 160         debug_print_probes(entry);
 161         /* (N -> M), (N > 1, M >= 0) probes */
 162         for (nr_probes = 0; old[nr_probes]; nr_probes++) {
 163                 if ((!probe || old[nr_probes] == probe))
 164                         nr_del++;
 165         }
 166
 167         if (nr_probes - nr_del == 0) {
 168                 /* N -> 0, (N > 1) */
 169                 entry->funcs = NULL;
 170                 entry->refcount = 0;
 171                 debug_print_probes(entry);
 172                 return old;
 173         } else {
 174                 int j = 0;
 175                 /* N -> M, (N > 1, M > 0) */
 176                 /* + 1 for NULL */
 177                 new = allocate_probes(nr_probes - nr_del + 1);
 178                 if (new == NULL)
 179                         return ERR_PTR(-ENOMEM);
 180                 for (i = 0; old[i]; i++)
 181                         if ((probe && old[i] != probe))
 182                                 new[j++] = old[i];
 183                 new[nr_probes - nr_del] = NULL;
 184                 entry->refcount = nr_probes - nr_del;
 185                 entry->funcs = new;
 186         }
 187         debug_print_probes(entry);
 188         return old;
 189 }
 190
 191 /*
 192  * Get tracepoint if the tracepoint is present in the tracepoint hash table.
 193  * Must be called with tracepoints_mutex held.
 194  * Returns NULL if not present.
 195  */
 196 static struct tracepoint_entry *get_tracepoint(const char *name)
 197 {
 198         struct hlist_head *head;
 199         struct hlist_node *node;
 200         struct tracepoint_entry *e;
 201         u32 hash = jhash(name, strlen(name), 0);
 202
 203         head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
 204         hlist_for_each_entry(e, node, head, hlist) {
 205                 if (!strcmp(name, e->name))
 206                         return e;
 207         }
 208         return NULL;
 209 }
 210
 211 /*
 212  * Add the tracepoint to the tracepoint hash table. Must be called with
 213  * tracepoints_mutex held.
 214  */
 215 static struct tracepoint_entry *add_tracepoint(const char *name)
 216 {
 217         struct hlist_head *head;
 218         struct hlist_node *node;
 219         struct tracepoint_entry *e;
 220         size_t name_len = strlen(name) + 1;
 221         u32 hash = jhash(name, name_len-1, 0);
 222
 223         head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
 224         hlist_for_each_entry(e, node, head, hlist) {
 225                 if (!strcmp(name, e->name)) {
 226                         printk(KERN_NOTICE
 227                                 "tracepoint %s busy\n", name);
 228                         return ERR_PTR(-EEXIST);        /* Already there */
 229                 }
 230         }
 231         /*
 232          * Using kmalloc here to allocate a variable length element. Could
 233          * cause some memory fragmentation if overused.
 234          */
 235         e = kmalloc(sizeof(struct tracepoint_entry) + name_len, GFP_KERNEL);
 236         if (!e)
 237                 return ERR_PTR(-ENOMEM);
 238         memcpy(&e->name[0], name, name_len);
 239         e->funcs = NULL;
 240         e->refcount = 0;
 241         hlist_add_head(&e->hlist, head);
 242         return e;
 243 }
 244
 245 /*
 246  * Remove the tracepoint from the tracepoint hash table. Must be called with
 247  * mutex_lock held.
 248  */
 249 static inline void remove_tracepoint(struct tracepoint_entry *e)
 250 {
 251         hlist_del(&e->hlist);
 252         kfree(e);
 253 }
 254
 255 /*
 256  * Sets the probe callback corresponding to one tracepoint.
 257  */
 258 static void set_tracepoint(struct tracepoint_entry **entry,
 259         struct tracepoint *elem, int active)
 260 {
 261         WARN_ON(strcmp((*entry)->name, elem->name) != 0);
 262
 263         /*
 264          * rcu_assign_pointer has a smp_wmb() which makes sure that the new
 265          * probe callbacks array is consistent before setting a pointer to it.
 266          * This array is referenced by __DO_TRACE from
 267          * include/linux/tracepoints.h. A matching smp_read_barrier_depends()
 268          * is used.
 269          */
 270         rcu_assign_pointer(elem->funcs, (*entry)->funcs);
 271         elem->state__imv = active;
 272 }
 273
 274 /*
 275  * Disable a tracepoint and its probe callback.
 276  * Note: only waiting an RCU period after setting elem->call to the empty
 277  * function insures that the original callback is not used anymore. This insured
 278  * by preempt_disable around the call site.
 279  */
 280 static void disable_tracepoint(struct tracepoint *elem)
 281 {
 282         elem->state__imv = 0;
 283         rcu_assign_pointer(elem->funcs, NULL);
 284 }
 285
 286 /**
 287  * tracepoint_update_probe_range - Update a probe range
 288  * @begin: beginning of the range
 289  * @end: end of the range
 290  *
 291  * Updates the probe callback corresponding to a range of tracepoints.
 292  */
 293 void tracepoint_update_probe_range(struct tracepoint *begin,
 294         struct tracepoint *end)
 295 {
 296         struct tracepoint *iter;
 297         struct tracepoint_entry *mark_entry;
 298
 299         mutex_lock(&tracepoints_mutex);
 300         for (iter = begin; iter < end; iter++) {
 301                 mark_entry = get_tracepoint(iter->name);
 302                 if (mark_entry) {
 303                         set_tracepoint(&mark_entry, iter,
 304                                         !!mark_entry->refcount);
 305                 } else {
 306                         disable_tracepoint(iter);
 307                 }
 308         }
 309         mutex_unlock(&tracepoints_mutex);
 310 }
 311
 312 /*
 313  * Update probes, removing the faulty probes.
 314  */
 315 static void tracepoint_update_probes(void)
 316 {
 317         /* Core kernel tracepoints */
 318 //ust// tracepoint_update_probe_range(__start___tracepoints,
 319 //ust//         __stop___tracepoints);
 320         /* tracepoints in modules. */
 321         lib_update_tracepoints();
 322         /* Update immediate values */
 323         core_imv_update();
 324 //ust// module_imv_update();
 325 }
 326
 327 static void *tracepoint_add_probe(const char *name, void *probe)
 328 {
 329         struct tracepoint_entry *entry;
 330         void *old;
 331
 332         entry = get_tracepoint(name);
 333         if (!entry) {
 334                 entry = add_tracepoint(name);
 335                 if (IS_ERR(entry))
 336                         return entry;
 337         }
 338         old = tracepoint_entry_add_probe(entry, probe);
 339         if (IS_ERR(old) && !entry->refcount)
 340                 remove_tracepoint(entry);
 341         return old;
 342 }
 343
 344 /**
 345  * tracepoint_probe_register -  Connect a probe to a tracepoint
 346  * @name: tracepoint name
 347  * @probe: probe handler
 348  *
 349  * Returns 0 if ok, error value on error.
 350  * The probe address must at least be aligned on the architecture pointer size.
 351  */
 352 int tracepoint_probe_register(const char *name, void *probe)
 353 {
 354         void *old;
 355
 356         mutex_lock(&tracepoints_mutex);
 357         old = tracepoint_add_probe(name, probe);
 358         mutex_unlock(&tracepoints_mutex);
 359         if (IS_ERR(old))
 360                 return PTR_ERR(old);
 361
 362         tracepoint_update_probes();             /* may update entry */
 363         release_probes(old);
 364         return 0;
 365 }
 366 //ust// EXPORT_SYMBOL_GPL(tracepoint_probe_register);
 367
 368 static void *tracepoint_remove_probe(const char *name, void *probe)
 369 {
 370         struct tracepoint_entry *entry;
 371         void *old;
 372
 373         entry = get_tracepoint(name);
 374         if (!entry)
 375                 return ERR_PTR(-ENOENT);
 376         old = tracepoint_entry_remove_probe(entry, probe);
 377         if (IS_ERR(old))
 378                 return old;
 379         if (!entry->refcount)
 380                 remove_tracepoint(entry);
 381         return old;
 382 }
 383
 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  */
 394 int tracepoint_probe_unregister(const char *name, void *probe)
 395 {
 396         void *old;
 397
 398         mutex_lock(&tracepoints_mutex);
 399         old = tracepoint_remove_probe(name, probe);
 400         mutex_unlock(&tracepoints_mutex);
 401         if (IS_ERR(old))
 402                 return PTR_ERR(old);
 403
 404         tracepoint_update_probes();             /* may update entry */
 405         release_probes(old);
 406         return 0;
 407 }
 408 //ust// EXPORT_SYMBOL_GPL(tracepoint_probe_unregister);
 409
 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  */
 430 int tracepoint_probe_register_noupdate(const char *name, void *probe)
 431 {
 432         void *old;
 433
 434         mutex_lock(&tracepoints_mutex);
 435         old = tracepoint_add_probe(name, probe);
 436         if (IS_ERR(old)) {
 437                 mutex_unlock(&tracepoints_mutex);
 438                 return PTR_ERR(old);
 439         }
 440         tracepoint_add_old_probes(old);
 441         mutex_unlock(&tracepoints_mutex);
 442         return 0;
 443 }
 444 //ust// EXPORT_SYMBOL_GPL(tracepoint_probe_register_noupdate);
 445
 446 /**
 447  * tracepoint_probe_unregister_noupdate -  remove a probe but not disconnect
 448  * @name: tracepoint name
 449  * @probe: probe function pointer
 450  *
 451  * caller must call tracepoint_probe_update_all()
 452  */
 453 int tracepoint_probe_unregister_noupdate(const char *name, void *probe)
 454 {
 455         void *old;
 456
 457         mutex_lock(&tracepoints_mutex);
 458         old = tracepoint_remove_probe(name, probe);
 459         if (IS_ERR(old)) {
 460                 mutex_unlock(&tracepoints_mutex);
 461                 return PTR_ERR(old);
 462         }
 463         tracepoint_add_old_probes(old);
 464         mutex_unlock(&tracepoints_mutex);
 465         return 0;
 466 }
 467 //ust// EXPORT_SYMBOL_GPL(tracepoint_probe_unregister_noupdate);
 468
 469 /**
 470  * tracepoint_probe_update_all -  update tracepoints
 471  */
 472 void tracepoint_probe_update_all(void)
 473 {
 474         LIST_HEAD(release_probes);
 475         struct tp_probes *pos, *next;
 476
 477         mutex_lock(&tracepoints_mutex);
 478         if (!need_update) {
 479                 mutex_unlock(&tracepoints_mutex);
 480                 return;
 481         }
 482         if (!list_empty(&old_probes))
 483                 list_replace_init(&old_probes, &release_probes);
 484         need_update = 0;
 485         mutex_unlock(&tracepoints_mutex);
 486
 487         tracepoint_update_probes();
 488         list_for_each_entry_safe(pos, next, &release_probes, u.list) {
 489                 list_del(&pos->u.list);
 490 //ust//         call_rcu_sched(&pos->u.rcu, rcu_free_old_probes);
 491                 synchronize_rcu();
 492                 kfree(pos);
 493         }
 494 }
 495 //ust// EXPORT_SYMBOL_GPL(tracepoint_probe_update_all);
 496
 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 //ust// 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 //ust// /* Core kernel tracepoints */
 525 //ust// if (!iter->module) {
 526 //ust//         found = tracepoint_get_iter_range(&iter->tracepoint,
 527 //ust//                         __start___tracepoints, __stop___tracepoints);
 528 //ust//         if (found)
 529 //ust//                 goto end;
 530 //ust// }
 531         /* tracepoints in libs. */
 532         found = lib_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 //ust// 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 //ust// EXPORT_SYMBOL_GPL(tracepoint_iter_next);
 555
 556 void tracepoint_iter_stop(struct tracepoint_iter *iter)
 557 {
 558 }
 559 //ust// EXPORT_SYMBOL_GPL(tracepoint_iter_stop);
 560
 561 void tracepoint_iter_reset(struct tracepoint_iter *iter)
 562 {
 563 //ust// iter->module = NULL;
 564         iter->tracepoint = NULL;
 565 }
 566 //ust// EXPORT_SYMBOL_GPL(tracepoint_iter_reset);
 567
 568 //ust// #ifdef CONFIG_MODULES
 569
 570 //ust// int tracepoint_module_notify(struct notifier_block *self,
 571 //ust//                              unsigned long val, void *data)
 572 //ust// {
 573 //ust//         struct module *mod = data;
 574 //ust//
 575 //ust//         switch (val) {
 576 //ust//         case MODULE_STATE_COMING:
 577 //ust//                 tracepoint_update_probe_range(mod->tracepoints,
 578 //ust//                         mod->tracepoints + mod->num_tracepoints);
 579 //ust//                 break;
 580 //ust//         case MODULE_STATE_GOING:
 581 //ust//                 tracepoint_update_probe_range(mod->tracepoints,
 582 //ust//                         mod->tracepoints + mod->num_tracepoints);
 583 //ust//                 break;
 584 //ust//         }
 585 //ust//         return 0;
 586 //ust// }
 587
 588 //ust// struct notifier_block tracepoint_module_nb = {
 589 //ust//         .notifier_call = tracepoint_module_notify,
 590 //ust//         .priority = 0,
 591 //ust// };
 592
 593 //ust// static int init_tracepoints(void)
 594 //ust// {
 595 //ust//         return register_module_notifier(&tracepoint_module_nb);
 596 //ust// }
 597 //ust// __initcall(init_tracepoints);
 598
 599 //ust// #endif /* CONFIG_MODULES */
 600
 601 /*
 602  * Returns 0 if current not found.
 603  * Returns 1 if current found.
 604  */
 605 int lib_get_iter_tracepoints(struct tracepoint_iter *iter)
 606 {
 607         struct tracepoint_lib *iter_lib;
 608         int found = 0;
 609
 610 //ust// mutex_lock(&module_mutex);
 611         list_for_each_entry(iter_lib, &libs, list) {
 612                 if (iter_lib < iter->lib)
 613                         continue;
 614                 else if (iter_lib > iter->lib)
 615                         iter->tracepoint = NULL;
 616                 found = marker_get_iter_range(&iter->tracepoint,
 617                         iter_lib->tracepoints_start,
 618                         iter_lib->tracepoints_start + iter_lib->tracepoints_count);
 619                 if (found) {
 620                         iter->lib = iter_lib;
 621                         break;
 622                 }
 623         }
 624 //ust// mutex_unlock(&module_mutex);
 625         return found;
 626 }
 627
 628 void lib_update_tracepoints(void)
 629 {
 630         struct tracepoint_lib *lib;
 631
 632 //ust// mutex_lock(&module_mutex);
 633         list_for_each_entry(lib, &libs, list)
 634                 tracepoint_update_probe_range(lib->tracepoints_start,
 635                                 lib->tracepoints_start + lib->tracepoints_count);
 636 //ust// mutex_unlock(&module_mutex);
 637 }
 638
 639 static void (*new_tracepoint_cb)(struct tracepoint *) = NULL;
 640
 641 void tracepoint_set_new_tracepoint_cb(void (*cb)(struct tracepoint *))
 642 {
 643         new_tracepoint_cb = cb;
 644 }
 645
 646 static void new_tracepoints(struct tracepoint *start, struct tracepoint *end)
 647 {
 648         if(new_tracepoint_cb) {
 649                 struct tracepoint *t;
 650                 for(t=start; t < end; t++) {
 651                         new_tracepoint_cb(t);
 652                 }
 653         }
 654 }
 655
 656 int tracepoint_register_lib(struct tracepoint *tracepoints_start, int tracepoints_count)
 657 {
 658         struct tracepoint_lib *pl;
 659
 660         pl = (struct tracepoint_lib *) malloc(sizeof(struct tracepoint_lib));
 661
 662         pl->tracepoints_start = tracepoints_start;
 663         pl->tracepoints_count = tracepoints_count;
 664
 665         /* FIXME: maybe protect this with its own mutex? */
 666         mutex_lock(&tracepoints_mutex);
 667         list_add(&pl->list, &libs);
 668         mutex_unlock(&tracepoints_mutex);
 669
 670         new_tracepoints(tracepoints_start, tracepoints_start + tracepoints_count);
 671
 672         /* FIXME: update just the loaded lib */
 673         lib_update_tracepoints();
 674
 675         DBG("just registered a tracepoints section from %p and having %d tracepoints", tracepoints_start, tracepoints_count);
 676
 677         return 0;
 678 }
 679
 680 int tracepoint_unregister_lib(struct tracepoint *tracepoints_start, int tracepoints_count)
 681 {
 682         /*FIXME: implement; but before implementing, tracepoint_register_lib must
 683           have appropriate locking. */
 684
 685         return 0;
 686 }