libust/marker.c

   1 /*
   2  * Copyright (C) 2007 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 //ust// #include <linux/module.h>
  19 //ust// #include <linux/mutex.h>
  20 //ust// #include <linux/types.h>
  21 //#include "jhash.h"
  22 //#include "list.h"
  23 //#include "rcupdate.h"
  24 //ust// #include <linux/marker.h>
  25 #include <errno.h>
  26 //ust// #include <linux/slab.h>
  27 //ust// #include <linux/immediate.h>
  28 //ust// #include <linux/sched.h>
  29 //ust// #include <linux/uaccess.h>
  30 //ust// #include <linux/user_marker.h>
  31 //ust// #include <linux/ltt-tracer.h>
  32
  33 #include "marker.h"
  34 #include "kernelcompat.h"
  35 #include "usterr.h"
  36 #include "channels.h"
  37 #include "tracercore.h"
  38 #include "tracer.h"
  39 #include "urcu.h"
  40
  41 extern struct marker __start___markers[] __attribute__((visibility("hidden")));
  42 extern struct marker __stop___markers[] __attribute__((visibility("hidden")));
  43
  44 /* Set to 1 to enable marker debug output */
  45 static const int marker_debug;
  46
  47 /*
  48  * markers_mutex nests inside module_mutex. Markers mutex protects the builtin
  49  * and module markers and the hash table.
  50  */
  51 static DEFINE_MUTEX(markers_mutex);
  52
  53 void lock_markers(void)
  54 {
  55         mutex_lock(&markers_mutex);
  56 }
  57
  58 void unlock_markers(void)
  59 {
  60         mutex_unlock(&markers_mutex);
  61 }
  62
  63 /*
  64  * Marker hash table, containing the active markers.
  65  * Protected by module_mutex.
  66  */
  67 #define MARKER_HASH_BITS 6
  68 #define MARKER_TABLE_SIZE (1 << MARKER_HASH_BITS)
  69 static struct hlist_head marker_table[MARKER_TABLE_SIZE];
  70
  71 /*
  72  * Note about RCU :
  73  * It is used to make sure every handler has finished using its private data
  74  * between two consecutive operation (add or remove) on a given marker.  It is
  75  * also used to delay the free of multiple probes array until a quiescent state
  76  * is reached.
  77  * marker entries modifications are protected by the markers_mutex.
  78  */
  79 struct marker_entry {
  80         struct hlist_node hlist;
  81         char *format;
  82         char *name;
  83                         /* Probe wrapper */
  84         void (*call)(const struct marker *mdata, void *call_private, ...);
  85         struct marker_probe_closure single;
  86         struct marker_probe_closure *multi;
  87         int refcount;   /* Number of times armed. 0 if disarmed. */
  88         struct rcu_head rcu;
  89         void *oldptr;
  90         int rcu_pending;
  91         u16 channel_id;
  92         u16 event_id;
  93         unsigned char ptype:1;
  94         unsigned char format_allocated:1;
  95         char channel[0];        /* Contains channel'\0'name'\0'format'\0' */
  96 };
  97
  98 #ifdef CONFIG_MARKERS_USERSPACE
  99 static void marker_update_processes(void);
 100 #else
 101 static void marker_update_processes(void)
 102 {
 103 }
 104 #endif
 105
 106 /**
 107  * __mark_empty_function - Empty probe callback
 108  * @mdata: marker data
 109  * @probe_private: probe private data
 110  * @call_private: call site private data
 111  * @fmt: format string
 112  * @...: variable argument list
 113  *
 114  * Empty callback provided as a probe to the markers. By providing this to a
 115  * disabled marker, we make sure the  execution flow is always valid even
 116  * though the function pointer change and the marker enabling are two distinct
 117  * operations that modifies the execution flow of preemptible code.
 118  */
 119 notrace void __mark_empty_function(const struct marker *mdata,
 120         void *probe_private, void *call_private, const char *fmt, va_list *args)
 121 {
 122 }
 123 //ust// EXPORT_SYMBOL_GPL(__mark_empty_function);
 124
 125 /*
 126  * marker_probe_cb Callback that prepares the variable argument list for probes.
 127  * @mdata: pointer of type struct marker
 128  * @call_private: caller site private data
 129  * @...:  Variable argument list.
 130  *
 131  * Since we do not use "typical" pointer based RCU in the 1 argument case, we
 132  * need to put a full smp_rmb() in this branch. This is why we do not use
 133  * rcu_dereference() for the pointer read.
 134  */
 135 notrace void marker_probe_cb(const struct marker *mdata,
 136                 void *call_private, ...)
 137 {
 138         va_list args;
 139         char ptype;
 140
 141         /*
 142          * rcu_read_lock_sched does two things : disabling preemption to make
 143          * sure the teardown of the callbacks can be done correctly when they
 144          * are in modules and they insure RCU read coherency.
 145          */
 146 //ust// rcu_read_lock_sched_notrace();
 147         ptype = mdata->ptype;
 148         if (likely(!ptype)) {
 149                 marker_probe_func *func;
 150                 /* Must read the ptype before ptr. They are not data dependant,
 151                  * so we put an explicit smp_rmb() here. */
 152                 smp_rmb();
 153                 func = mdata->single.func;
 154                 /* Must read the ptr before private data. They are not data
 155                  * dependant, so we put an explicit smp_rmb() here. */
 156                 smp_rmb();
 157                 va_start(args, call_private);
 158                 func(mdata, mdata->single.probe_private, call_private,
 159                         mdata->format, &args);
 160                 va_end(args);
 161         } else {
 162                 struct marker_probe_closure *multi;
 163                 int i;
 164                 /*
 165                  * Read mdata->ptype before mdata->multi.
 166                  */
 167                 smp_rmb();
 168                 multi = mdata->multi;
 169                 /*
 170                  * multi points to an array, therefore accessing the array
 171                  * depends on reading multi. However, even in this case,
 172                  * we must insure that the pointer is read _before_ the array
 173                  * data. Same as rcu_dereference, but we need a full smp_rmb()
 174                  * in the fast path, so put the explicit barrier here.
 175                  */
 176                 smp_read_barrier_depends();
 177                 for (i = 0; multi[i].func; i++) {
 178                         va_start(args, call_private);
 179                         multi[i].func(mdata, multi[i].probe_private,
 180                                 call_private, mdata->format, &args);
 181                         va_end(args);
 182                 }
 183         }
 184 //ust// rcu_read_unlock_sched_notrace();
 185 }
 186 //ust// EXPORT_SYMBOL_GPL(marker_probe_cb);
 187
 188 /*
 189  * marker_probe_cb Callback that does not prepare the variable argument list.
 190  * @mdata: pointer of type struct marker
 191  * @call_private: caller site private data
 192  * @...:  Variable argument list.
 193  *
 194  * Should be connected to markers "MARK_NOARGS".
 195  */
 196 static notrace void marker_probe_cb_noarg(const struct marker *mdata,
 197                 void *call_private, ...)
 198 {
 199         va_list args;   /* not initialized */
 200         char ptype;
 201
 202 //ust// rcu_read_lock_sched_notrace();
 203         ptype = mdata->ptype;
 204         if (likely(!ptype)) {
 205                 marker_probe_func *func;
 206                 /* Must read the ptype before ptr. They are not data dependant,
 207                  * so we put an explicit smp_rmb() here. */
 208                 smp_rmb();
 209                 func = mdata->single.func;
 210                 /* Must read the ptr before private data. They are not data
 211                  * dependant, so we put an explicit smp_rmb() here. */
 212                 smp_rmb();
 213                 func(mdata, mdata->single.probe_private, call_private,
 214                         mdata->format, &args);
 215         } else {
 216                 struct marker_probe_closure *multi;
 217                 int i;
 218                 /*
 219                  * Read mdata->ptype before mdata->multi.
 220                  */
 221                 smp_rmb();
 222                 multi = mdata->multi;
 223                 /*
 224                  * multi points to an array, therefore accessing the array
 225                  * depends on reading multi. However, even in this case,
 226                  * we must insure that the pointer is read _before_ the array
 227                  * data. Same as rcu_dereference, but we need a full smp_rmb()
 228                  * in the fast path, so put the explicit barrier here.
 229                  */
 230                 smp_read_barrier_depends();
 231                 for (i = 0; multi[i].func; i++)
 232                         multi[i].func(mdata, multi[i].probe_private,
 233                                 call_private, mdata->format, &args);
 234         }
 235 //ust// rcu_read_unlock_sched_notrace();
 236 }
 237
 238 static void free_old_closure(struct rcu_head *head)
 239 {
 240         struct marker_entry *entry = container_of(head,
 241                 struct marker_entry, rcu);
 242         kfree(entry->oldptr);
 243         /* Make sure we free the data before setting the pending flag to 0 */
 244         smp_wmb();
 245         entry->rcu_pending = 0;
 246 }
 247
 248 static void debug_print_probes(struct marker_entry *entry)
 249 {
 250         int i;
 251
 252         if (!marker_debug)
 253                 return;
 254
 255         if (!entry->ptype) {
 256                 printk(KERN_DEBUG "Single probe : %p %p\n",
 257                         entry->single.func,
 258                         entry->single.probe_private);
 259         } else {
 260                 for (i = 0; entry->multi[i].func; i++)
 261                         printk(KERN_DEBUG "Multi probe %d : %p %p\n", i,
 262                                 entry->multi[i].func,
 263                                 entry->multi[i].probe_private);
 264         }
 265 }
 266
 267 static struct marker_probe_closure *
 268 marker_entry_add_probe(struct marker_entry *entry,
 269                 marker_probe_func *probe, void *probe_private)
 270 {
 271         int nr_probes = 0;
 272         struct marker_probe_closure *old, *new;
 273
 274         WARN_ON(!probe);
 275
 276         debug_print_probes(entry);
 277         old = entry->multi;
 278         if (!entry->ptype) {
 279                 if (entry->single.func == probe &&
 280                                 entry->single.probe_private == probe_private)
 281                         return ERR_PTR(-EBUSY);
 282                 if (entry->single.func == __mark_empty_function) {
 283                         /* 0 -> 1 probes */
 284                         entry->single.func = probe;
 285                         entry->single.probe_private = probe_private;
 286                         entry->refcount = 1;
 287                         entry->ptype = 0;
 288                         debug_print_probes(entry);
 289                         return NULL;
 290                 } else {
 291                         /* 1 -> 2 probes */
 292                         nr_probes = 1;
 293                         old = NULL;
 294                 }
 295         } else {
 296                 /* (N -> N+1), (N != 0, 1) probes */
 297                 for (nr_probes = 0; old[nr_probes].func; nr_probes++)
 298                         if (old[nr_probes].func == probe
 299                                         && old[nr_probes].probe_private
 300                                                 == probe_private)
 301                                 return ERR_PTR(-EBUSY);
 302         }
 303         /* + 2 : one for new probe, one for NULL func */
 304         new = kzalloc((nr_probes + 2) * sizeof(struct marker_probe_closure),
 305                         GFP_KERNEL);
 306         if (new == NULL)
 307                 return ERR_PTR(-ENOMEM);
 308         if (!old)
 309                 new[0] = entry->single;
 310         else
 311                 memcpy(new, old,
 312                         nr_probes * sizeof(struct marker_probe_closure));
 313         new[nr_probes].func = probe;
 314         new[nr_probes].probe_private = probe_private;
 315         entry->refcount = nr_probes + 1;
 316         entry->multi = new;
 317         entry->ptype = 1;
 318         debug_print_probes(entry);
 319         return old;
 320 }
 321
 322 static struct marker_probe_closure *
 323 marker_entry_remove_probe(struct marker_entry *entry,
 324                 marker_probe_func *probe, void *probe_private)
 325 {
 326         int nr_probes = 0, nr_del = 0, i;
 327         struct marker_probe_closure *old, *new;
 328
 329         old = entry->multi;
 330
 331         debug_print_probes(entry);
 332         if (!entry->ptype) {
 333                 /* 0 -> N is an error */
 334                 WARN_ON(entry->single.func == __mark_empty_function);
 335                 /* 1 -> 0 probes */
 336                 WARN_ON(probe && entry->single.func != probe);
 337                 WARN_ON(entry->single.probe_private != probe_private);
 338                 entry->single.func = __mark_empty_function;
 339                 entry->refcount = 0;
 340                 entry->ptype = 0;
 341                 debug_print_probes(entry);
 342                 return NULL;
 343         } else {
 344                 /* (N -> M), (N > 1, M >= 0) probes */
 345                 for (nr_probes = 0; old[nr_probes].func; nr_probes++) {
 346                         if ((!probe || old[nr_probes].func == probe)
 347                                         && old[nr_probes].probe_private
 348                                                 == probe_private)
 349                                 nr_del++;
 350                 }
 351         }
 352
 353         if (nr_probes - nr_del == 0) {
 354                 /* N -> 0, (N > 1) */
 355                 entry->single.func = __mark_empty_function;
 356                 entry->refcount = 0;
 357                 entry->ptype = 0;
 358         } else if (nr_probes - nr_del == 1) {
 359                 /* N -> 1, (N > 1) */
 360                 for (i = 0; old[i].func; i++)
 361                         if ((probe && old[i].func != probe) ||
 362                                         old[i].probe_private != probe_private)
 363                                 entry->single = old[i];
 364                 entry->refcount = 1;
 365                 entry->ptype = 0;
 366         } else {
 367                 int j = 0;
 368                 /* N -> M, (N > 1, M > 1) */
 369                 /* + 1 for NULL */
 370                 new = kzalloc((nr_probes - nr_del + 1)
 371                         * sizeof(struct marker_probe_closure), GFP_KERNEL);
 372                 if (new == NULL)
 373                         return ERR_PTR(-ENOMEM);
 374                 for (i = 0; old[i].func; i++)
 375                         if ((probe && old[i].func != probe) ||
 376                                         old[i].probe_private != probe_private)
 377                                 new[j++] = old[i];
 378                 entry->refcount = nr_probes - nr_del;
 379                 entry->ptype = 1;
 380                 entry->multi = new;
 381         }
 382         debug_print_probes(entry);
 383         return old;
 384 }
 385
 386 /*
 387  * Get marker if the marker is present in the marker hash table.
 388  * Must be called with markers_mutex held.
 389  * Returns NULL if not present.
 390  */
 391 static struct marker_entry *get_marker(const char *channel, const char *name)
 392 {
 393         struct hlist_head *head;
 394         struct hlist_node *node;
 395         struct marker_entry *e;
 396         size_t channel_len = strlen(channel) + 1;
 397         size_t name_len = strlen(name) + 1;
 398         u32 hash;
 399
 400         hash = jhash(channel, channel_len-1, 0) ^ jhash(name, name_len-1, 0);
 401         head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)];
 402         hlist_for_each_entry(e, node, head, hlist) {
 403                 if (!strcmp(channel, e->channel) && !strcmp(name, e->name))
 404                         return e;
 405         }
 406         return NULL;
 407 }
 408
 409 /*
 410  * Add the marker to the marker hash table. Must be called with markers_mutex
 411  * held.
 412  */
 413 static struct marker_entry *add_marker(const char *channel, const char *name,
 414                 const char *format)
 415 {
 416         struct hlist_head *head;
 417         struct hlist_node *node;
 418         struct marker_entry *e;
 419         size_t channel_len = strlen(channel) + 1;
 420         size_t name_len = strlen(name) + 1;
 421         size_t format_len = 0;
 422         u32 hash;
 423
 424         hash = jhash(channel, channel_len-1, 0) ^ jhash(name, name_len-1, 0);
 425         if (format)
 426                 format_len = strlen(format) + 1;
 427         head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)];
 428         hlist_for_each_entry(e, node, head, hlist) {
 429                 if (!strcmp(channel, e->channel) && !strcmp(name, e->name)) {
 430                         printk(KERN_NOTICE
 431                                 "Marker %s.%s busy\n", channel, name);
 432                         return ERR_PTR(-EBUSY); /* Already there */
 433                 }
 434         }
 435         /*
 436          * Using kmalloc here to allocate a variable length element. Could
 437          * cause some memory fragmentation if overused.
 438          */
 439         e = kmalloc(sizeof(struct marker_entry)
 440                     + channel_len + name_len + format_len,
 441                     GFP_KERNEL);
 442         if (!e)
 443                 return ERR_PTR(-ENOMEM);
 444         memcpy(e->channel, channel, channel_len);
 445         e->name = &e->channel[channel_len];
 446         memcpy(e->name, name, name_len);
 447         if (format) {
 448                 e->format = &e->name[channel_len + name_len];
 449                 memcpy(e->format, format, format_len);
 450                 if (strcmp(e->format, MARK_NOARGS) == 0)
 451                         e->call = marker_probe_cb_noarg;
 452                 else
 453                         e->call = marker_probe_cb;
 454                 trace_mark(metadata, core_marker_format,
 455                            "channel %s name %s format %s",
 456                            e->channel, e->name, e->format);
 457         } else {
 458                 e->format = NULL;
 459                 e->call = marker_probe_cb;
 460         }
 461         e->single.func = __mark_empty_function;
 462         e->single.probe_private = NULL;
 463         e->multi = NULL;
 464         e->ptype = 0;
 465         e->format_allocated = 0;
 466         e->refcount = 0;
 467         e->rcu_pending = 0;
 468         hlist_add_head(&e->hlist, head);
 469         return e;
 470 }
 471
 472 /*
 473  * Remove the marker from the marker hash table. Must be called with mutex_lock
 474  * held.
 475  */
 476 static int remove_marker(const char *channel, const char *name)
 477 {
 478         struct hlist_head *head;
 479         struct hlist_node *node;
 480         struct marker_entry *e;
 481         int found = 0;
 482         size_t channel_len = strlen(channel) + 1;
 483         size_t name_len = strlen(name) + 1;
 484         u32 hash;
 485         int ret;
 486
 487         hash = jhash(channel, channel_len-1, 0) ^ jhash(name, name_len-1, 0);
 488         head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)];
 489         hlist_for_each_entry(e, node, head, hlist) {
 490                 if (!strcmp(channel, e->channel) && !strcmp(name, e->name)) {
 491                         found = 1;
 492                         break;
 493                 }
 494         }
 495         if (!found)
 496                 return -ENOENT;
 497         if (e->single.func != __mark_empty_function)
 498                 return -EBUSY;
 499         hlist_del(&e->hlist);
 500         if (e->format_allocated)
 501                 kfree(e->format);
 502         ret = ltt_channels_unregister(e->channel);
 503         WARN_ON(ret);
 504         /* Make sure the call_rcu has been executed */
 505 //ust// if (e->rcu_pending)
 506 //ust//         rcu_barrier_sched();
 507         kfree(e);
 508         return 0;
 509 }
 510
 511 /*
 512  * Set the mark_entry format to the format found in the element.
 513  */
 514 static int marker_set_format(struct marker_entry *entry, const char *format)
 515 {
 516         entry->format = kstrdup(format, GFP_KERNEL);
 517         if (!entry->format)
 518                 return -ENOMEM;
 519         entry->format_allocated = 1;
 520
 521         trace_mark(metadata, core_marker_format,
 522                    "channel %s name %s format %s",
 523                    entry->channel, entry->name, entry->format);
 524         return 0;
 525 }
 526
 527 /*
 528  * Sets the probe callback corresponding to one marker.
 529  */
 530 static int set_marker(struct marker_entry *entry, struct marker *elem,
 531                 int active)
 532 {
 533         int ret = 0;
 534         WARN_ON(strcmp(entry->name, elem->name) != 0);
 535
 536         if (entry->format) {
 537                 if (strcmp(entry->format, elem->format) != 0) {
 538                         printk(KERN_NOTICE
 539                                 "Format mismatch for probe %s "
 540                                 "(%s), marker (%s)\n",
 541                                 entry->name,
 542                                 entry->format,
 543                                 elem->format);
 544                         return -EPERM;
 545                 }
 546         } else {
 547                 ret = marker_set_format(entry, elem->format);
 548                 if (ret)
 549                         return ret;
 550         }
 551
 552         /*
 553          * probe_cb setup (statically known) is done here. It is
 554          * asynchronous with the rest of execution, therefore we only
 555          * pass from a "safe" callback (with argument) to an "unsafe"
 556          * callback (does not set arguments).
 557          */
 558         elem->call = entry->call;
 559         elem->channel_id = entry->channel_id;
 560         elem->event_id = entry->event_id;
 561         /*
 562          * Sanity check :
 563          * We only update the single probe private data when the ptr is
 564          * set to a _non_ single probe! (0 -> 1 and N -> 1, N != 1)
 565          */
 566         WARN_ON(elem->single.func != __mark_empty_function
 567                 && elem->single.probe_private != entry->single.probe_private
 568                 && !elem->ptype);
 569         elem->single.probe_private = entry->single.probe_private;
 570         /*
 571          * Make sure the private data is valid when we update the
 572          * single probe ptr.
 573          */
 574         smp_wmb();
 575         elem->single.func = entry->single.func;
 576         /*
 577          * We also make sure that the new probe callbacks array is consistent
 578          * before setting a pointer to it.
 579          */
 580         rcu_assign_pointer(elem->multi, entry->multi);
 581         /*
 582          * Update the function or multi probe array pointer before setting the
 583          * ptype.
 584          */
 585         smp_wmb();
 586         elem->ptype = entry->ptype;
 587
 588 //ust// if (elem->tp_name && (active ^ _imv_read(elem->state))) {
 589 //ust//         WARN_ON(!elem->tp_cb);
 590 //ust//         /*
 591 //ust//          * It is ok to directly call the probe registration because type
 592 //ust//          * checking has been done in the __trace_mark_tp() macro.
 593 //ust//          */
 594 //ust//
 595 //ust//         if (active) {
 596 //ust//                 /*
 597 //ust//                  * try_module_get should always succeed because we hold
 598 //ust//                  * markers_mutex to get the tp_cb address.
 599 //ust//                  */
 600 //ust//                 ret = try_module_get(__module_text_address(
 601 //ust//                         (unsigned long)elem->tp_cb));
 602 //ust//                 BUG_ON(!ret);
 603 //ust//                 ret = tracepoint_probe_register_noupdate(
 604 //ust//                         elem->tp_name,
 605 //ust//                         elem->tp_cb);
 606 //ust//         } else {
 607 //ust//                 ret = tracepoint_probe_unregister_noupdate(
 608 //ust//                         elem->tp_name,
 609 //ust//                         elem->tp_cb);
 610 //ust//                 /*
 611 //ust//                  * tracepoint_probe_update_all() must be called
 612 //ust//                  * before the module containing tp_cb is unloaded.
 613 //ust//                  */
 614 //ust//                 module_put(__module_text_address(
 615 //ust//                         (unsigned long)elem->tp_cb));
 616 //ust//         }
 617 //ust// }
 618         elem->state__imv = active;
 619
 620         return ret;
 621 }
 622
 623 /*
 624  * Disable a marker and its probe callback.
 625  * Note: only waiting an RCU period after setting elem->call to the empty
 626  * function insures that the original callback is not used anymore. This insured
 627  * by rcu_read_lock_sched around the call site.
 628  */
 629 static void disable_marker(struct marker *elem)
 630 {
 631         int ret;
 632
 633         /* leave "call" as is. It is known statically. */
 634 //ust// if (elem->tp_name && _imv_read(elem->state)) {
 635 //ust//         WARN_ON(!elem->tp_cb);
 636 //ust//         /*
 637 //ust//          * It is ok to directly call the probe registration because type
 638 //ust//          * checking has been done in the __trace_mark_tp() macro.
 639 //ust//          */
 640 //ust//         ret = tracepoint_probe_unregister_noupdate(elem->tp_name,
 641 //ust//                 elem->tp_cb);
 642 //ust//         WARN_ON(ret);
 643 //ust//         /*
 644 //ust//          * tracepoint_probe_update_all() must be called
 645 //ust//          * before the module containing tp_cb is unloaded.
 646 //ust//          */
 647 //ust//         module_put(__module_text_address((unsigned long)elem->tp_cb));
 648 //ust// }
 649         elem->state__imv = 0;
 650         elem->single.func = __mark_empty_function;
 651         /* Update the function before setting the ptype */
 652         smp_wmb();
 653         elem->ptype = 0;        /* single probe */
 654         /*
 655          * Leave the private data and channel_id/event_id there, because removal
 656          * is racy and should be done only after an RCU period. These are never
 657          * used until the next initialization anyway.
 658          */
 659 }
 660
 661 /**
 662  * marker_update_probe_range - Update a probe range
 663  * @begin: beginning of the range
 664  * @end: end of the range
 665  *
 666  * Updates the probe callback corresponding to a range of markers.
 667  */
 668 void marker_update_probe_range(struct marker *begin,
 669         struct marker *end)
 670 {
 671         struct marker *iter;
 672         struct marker_entry *mark_entry;
 673
 674         mutex_lock(&markers_mutex);
 675         for (iter = begin; iter < end; iter++) {
 676                 mark_entry = get_marker(iter->channel, iter->name);
 677                 if (mark_entry) {
 678                         set_marker(mark_entry, iter, !!mark_entry->refcount);
 679                         /*
 680                          * ignore error, continue
 681                          */
 682
 683                         /* This is added for UST. We emit a core_marker_id event
 684                          * for markers that are already registered to a probe
 685                          * upon library load. Otherwise, no core_marker_id will
 686                          * be generated for these markers. Is this the right thing
 687                          * to do?
 688                          */
 689                         trace_mark(metadata, core_marker_id,
 690                                    "channel %s name %s event_id %hu "
 691                                    "int #1u%zu long #1u%zu pointer #1u%zu "
 692                                    "size_t #1u%zu alignment #1u%u",
 693                                    iter->channel, iter->name, mark_entry->event_id,
 694                                    sizeof(int), sizeof(long), sizeof(void *),
 695                                    sizeof(size_t), ltt_get_alignment());
 696                 } else {
 697                         disable_marker(iter);
 698                 }
 699         }
 700         mutex_unlock(&markers_mutex);
 701 }
 702
 703 /*
 704  * Update probes, removing the faulty probes.
 705  *
 706  * Internal callback only changed before the first probe is connected to it.
 707  * Single probe private data can only be changed on 0 -> 1 and 2 -> 1
 708  * transitions.  All other transitions will leave the old private data valid.
 709  * This makes the non-atomicity of the callback/private data updates valid.
 710  *
 711  * "special case" updates :
 712  * 0 -> 1 callback
 713  * 1 -> 0 callback
 714  * 1 -> 2 callbacks
 715  * 2 -> 1 callbacks
 716  * Other updates all behave the same, just like the 2 -> 3 or 3 -> 2 updates.
 717  * Site effect : marker_set_format may delete the marker entry (creating a
 718  * replacement).
 719  */
 720 static void marker_update_probes(void)
 721 {
 722         /* Core kernel markers */
 723 //ust// marker_update_probe_range(__start___markers, __stop___markers);
 724         /* Markers in modules. */
 725 //ust// module_update_markers();
 726         lib_update_markers();
 727 //ust// tracepoint_probe_update_all();
 728         /* Update immediate values */
 729         core_imv_update();
 730 //ust// module_imv_update(); /* FIXME: need to port for libs? */
 731         marker_update_processes();
 732 }
 733
 734 /**
 735  * marker_probe_register -  Connect a probe to a marker
 736  * @channel: marker channel
 737  * @name: marker name
 738  * @format: format string
 739  * @probe: probe handler
 740  * @probe_private: probe private data
 741  *
 742  * private data must be a valid allocated memory address, or NULL.
 743  * Returns 0 if ok, error value on error.
 744  * The probe address must at least be aligned on the architecture pointer size.
 745  */
 746 int marker_probe_register(const char *channel, const char *name,
 747                           const char *format, marker_probe_func *probe,
 748                           void *probe_private)
 749 {
 750         struct marker_entry *entry;
 751         int ret = 0, ret_err;
 752         struct marker_probe_closure *old;
 753         int first_probe = 0;
 754
 755         mutex_lock(&markers_mutex);
 756         entry = get_marker(channel, name);
 757         if (!entry) {
 758                 first_probe = 1;
 759                 entry = add_marker(channel, name, format);
 760                 if (IS_ERR(entry))
 761                         ret = PTR_ERR(entry);
 762                 if (ret)
 763                         goto end;
 764                 ret = ltt_channels_register(channel);
 765                 if (ret)
 766                         goto error_remove_marker;
 767                 ret = ltt_channels_get_index_from_name(channel);
 768                 if (ret < 0)
 769                         goto error_unregister_channel;
 770                 entry->channel_id = ret;
 771                 ret = ltt_channels_get_event_id(channel, name);
 772                 if (ret < 0)
 773                         goto error_unregister_channel;
 774                 entry->event_id = ret;
 775                 ret = 0;
 776                 trace_mark(metadata, core_marker_id,
 777                            "channel %s name %s event_id %hu "
 778                            "int #1u%zu long #1u%zu pointer #1u%zu "
 779                            "size_t #1u%zu alignment #1u%u",
 780                            channel, name, entry->event_id,
 781                            sizeof(int), sizeof(long), sizeof(void *),
 782                            sizeof(size_t), ltt_get_alignment());
 783         } else if (format) {
 784                 if (!entry->format)
 785                         ret = marker_set_format(entry, format);
 786                 else if (strcmp(entry->format, format))
 787                         ret = -EPERM;
 788                 if (ret)
 789                         goto end;
 790         }
 791
 792         /*
 793          * If we detect that a call_rcu is pending for this marker,
 794          * make sure it's executed now.
 795          */
 796 //ust// if (entry->rcu_pending)
 797 //ust//         rcu_barrier_sched();
 798         old = marker_entry_add_probe(entry, probe, probe_private);
 799         if (IS_ERR(old)) {
 800                 ret = PTR_ERR(old);
 801                 if (first_probe)
 802                         goto error_unregister_channel;
 803                 else
 804                         goto end;
 805         }
 806         mutex_unlock(&markers_mutex);
 807
 808         marker_update_probes();
 809
 810         mutex_lock(&markers_mutex);
 811         entry = get_marker(channel, name);
 812         if (!entry)
 813                 goto end;
 814 //ust// if (entry->rcu_pending)
 815 //ust//         rcu_barrier_sched();
 816         entry->oldptr = old;
 817         entry->rcu_pending = 1;
 818         /* write rcu_pending before calling the RCU callback */
 819         smp_wmb();
 820 //ust// call_rcu_sched(&entry->rcu, free_old_closure);
 821         synchronize_rcu(); free_old_closure(&entry->rcu);
 822         goto end;
 823
 824 error_unregister_channel:
 825         ret_err = ltt_channels_unregister(channel);
 826         WARN_ON(ret_err);
 827 error_remove_marker:
 828         ret_err = remove_marker(channel, name);
 829         WARN_ON(ret_err);
 830 end:
 831         mutex_unlock(&markers_mutex);
 832         return ret;
 833 }
 834 //ust// EXPORT_SYMBOL_GPL(marker_probe_register);
 835
 836 /**
 837  * marker_probe_unregister -  Disconnect a probe from a marker
 838  * @channel: marker channel
 839  * @name: marker name
 840  * @probe: probe function pointer
 841  * @probe_private: probe private data
 842  *
 843  * Returns the private data given to marker_probe_register, or an ERR_PTR().
 844  * We do not need to call a synchronize_sched to make sure the probes have
 845  * finished running before doing a module unload, because the module unload
 846  * itself uses stop_machine(), which insures that every preempt disabled section
 847  * have finished.
 848  */
 849 int marker_probe_unregister(const char *channel, const char *name,
 850                             marker_probe_func *probe, void *probe_private)
 851 {
 852         struct marker_entry *entry;
 853         struct marker_probe_closure *old;
 854         int ret = -ENOENT;
 855
 856         mutex_lock(&markers_mutex);
 857         entry = get_marker(channel, name);
 858         if (!entry)
 859                 goto end;
 860 //ust// if (entry->rcu_pending)
 861 //ust//         rcu_barrier_sched();
 862         old = marker_entry_remove_probe(entry, probe, probe_private);
 863         mutex_unlock(&markers_mutex);
 864
 865         marker_update_probes();
 866
 867         mutex_lock(&markers_mutex);
 868         entry = get_marker(channel, name);
 869         if (!entry)
 870                 goto end;
 871 //ust// if (entry->rcu_pending)
 872 //ust//         rcu_barrier_sched();
 873         entry->oldptr = old;
 874         entry->rcu_pending = 1;
 875         /* write rcu_pending before calling the RCU callback */
 876         smp_wmb();
 877 //ust// call_rcu_sched(&entry->rcu, free_old_closure);
 878         synchronize_rcu(); free_old_closure(&entry->rcu);
 879         remove_marker(channel, name);   /* Ignore busy error message */
 880         ret = 0;
 881 end:
 882         mutex_unlock(&markers_mutex);
 883         return ret;
 884 }
 885 //ust// EXPORT_SYMBOL_GPL(marker_probe_unregister);
 886
 887 static struct marker_entry *
 888 get_marker_from_private_data(marker_probe_func *probe, void *probe_private)
 889 {
 890         struct marker_entry *entry;
 891         unsigned int i;
 892         struct hlist_head *head;
 893         struct hlist_node *node;
 894
 895         for (i = 0; i < MARKER_TABLE_SIZE; i++) {
 896                 head = &marker_table[i];
 897                 hlist_for_each_entry(entry, node, head, hlist) {
 898                         if (!entry->ptype) {
 899                                 if (entry->single.func == probe
 900                                                 && entry->single.probe_private
 901                                                 == probe_private)
 902                                         return entry;
 903                         } else {
 904                                 struct marker_probe_closure *closure;
 905                                 closure = entry->multi;
 906                                 for (i = 0; closure[i].func; i++) {
 907                                         if (closure[i].func == probe &&
 908                                                         closure[i].probe_private
 909                                                         == probe_private)
 910                                                 return entry;
 911                                 }
 912                         }
 913                 }
 914         }
 915         return NULL;
 916 }
 917
 918 /**
 919  * marker_probe_unregister_private_data -  Disconnect a probe from a marker
 920  * @probe: probe function
 921  * @probe_private: probe private data
 922  *
 923  * Unregister a probe by providing the registered private data.
 924  * Only removes the first marker found in hash table.
 925  * Return 0 on success or error value.
 926  * We do not need to call a synchronize_sched to make sure the probes have
 927  * finished running before doing a module unload, because the module unload
 928  * itself uses stop_machine(), which insures that every preempt disabled section
 929  * have finished.
 930  */
 931 int marker_probe_unregister_private_data(marker_probe_func *probe,
 932                 void *probe_private)
 933 {
 934         struct marker_entry *entry;
 935         int ret = 0;
 936         struct marker_probe_closure *old;
 937         const char *channel = NULL, *name = NULL;
 938
 939         mutex_lock(&markers_mutex);
 940         entry = get_marker_from_private_data(probe, probe_private);
 941         if (!entry) {
 942                 ret = -ENOENT;
 943                 goto end;
 944         }
 945 //ust// if (entry->rcu_pending)
 946 //ust//         rcu_barrier_sched();
 947         old = marker_entry_remove_probe(entry, NULL, probe_private);
 948         channel = kstrdup(entry->channel, GFP_KERNEL);
 949         name = kstrdup(entry->name, GFP_KERNEL);
 950         mutex_unlock(&markers_mutex);
 951
 952         marker_update_probes();
 953
 954         mutex_lock(&markers_mutex);
 955         entry = get_marker(channel, name);
 956         if (!entry)
 957                 goto end;
 958 //ust// if (entry->rcu_pending)
 959 //ust//         rcu_barrier_sched();
 960         entry->oldptr = old;
 961         entry->rcu_pending = 1;
 962         /* write rcu_pending before calling the RCU callback */
 963         smp_wmb();
 964 //ust// call_rcu_sched(&entry->rcu, free_old_closure);
 965         synchronize_rcu(); free_old_closure(&entry->rcu);
 966         /* Ignore busy error message */
 967         remove_marker(channel, name);
 968 end:
 969         mutex_unlock(&markers_mutex);
 970         kfree(channel);
 971         kfree(name);
 972         return ret;
 973 }
 974 //ust// EXPORT_SYMBOL_GPL(marker_probe_unregister_private_data);
 975
 976 /**
 977  * marker_get_private_data - Get a marker's probe private data
 978  * @channel: marker channel
 979  * @name: marker name
 980  * @probe: probe to match
 981  * @num: get the nth matching probe's private data
 982  *
 983  * Returns the nth private data pointer (starting from 0) matching, or an
 984  * ERR_PTR.
 985  * Returns the private data pointer, or an ERR_PTR.
 986  * The private data pointer should _only_ be dereferenced if the caller is the
 987  * owner of the data, or its content could vanish. This is mostly used to
 988  * confirm that a caller is the owner of a registered probe.
 989  */
 990 void *marker_get_private_data(const char *channel, const char *name,
 991                               marker_probe_func *probe, int num)
 992 {
 993         struct hlist_head *head;
 994         struct hlist_node *node;
 995         struct marker_entry *e;
 996         size_t channel_len = strlen(channel) + 1;
 997         size_t name_len = strlen(name) + 1;
 998         int i;
 999         u32 hash;
1000
1001         hash = jhash(channel, channel_len-1, 0) ^ jhash(name, name_len-1, 0);
1002         head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)];
1003         hlist_for_each_entry(e, node, head, hlist) {
1004                 if (!strcmp(channel, e->channel) && !strcmp(name, e->name)) {
1005                         if (!e->ptype) {
1006                                 if (num == 0 && e->single.func == probe)
1007                                         return e->single.probe_private;
1008                         } else {
1009                                 struct marker_probe_closure *closure;
1010                                 int match = 0;
1011                                 closure = e->multi;
1012                                 for (i = 0; closure[i].func; i++) {
1013                                         if (closure[i].func != probe)
1014                                                 continue;
1015                                         if (match++ == num)
1016                                                 return closure[i].probe_private;
1017                                 }
1018                         }
1019                         break;
1020                 }
1021         }
1022         return ERR_PTR(-ENOENT);
1023 }
1024 //ust// EXPORT_SYMBOL_GPL(marker_get_private_data);
1025
1026 /**
1027  * markers_compact_event_ids - Compact markers event IDs and reassign channels
1028  *
1029  * Called when no channel users are active by the channel infrastructure.
1030  * Called with lock_markers() and channel mutex held.
1031  */
1032 //ust// void markers_compact_event_ids(void)
1033 //ust// {
1034 //ust//         struct marker_entry *entry;
1035 //ust//         unsigned int i;
1036 //ust//         struct hlist_head *head;
1037 //ust//         struct hlist_node *node;
1038 //ust//         int ret;
1039 //ust//
1040 //ust//         for (i = 0; i < MARKER_TABLE_SIZE; i++) {
1041 //ust//                 head = &marker_table[i];
1042 //ust//                 hlist_for_each_entry(entry, node, head, hlist) {
1043 //ust//                         ret = ltt_channels_get_index_from_name(entry->channel);
1044 //ust//                         WARN_ON(ret < 0);
1045 //ust//                         entry->channel_id = ret;
1046 //ust//                         ret = _ltt_channels_get_event_id(entry->channel,
1047 //ust//                                                          entry->name);
1048 //ust//                         WARN_ON(ret < 0);
1049 //ust//                         entry->event_id = ret;
1050 //ust//                 }
1051 //ust//         }
1052 //ust// }
1053
1054 //ust//#ifdef CONFIG_MODULES
1055
1056 /**
1057  * marker_get_iter_range - Get a next marker iterator given a range.
1058  * @marker: current markers (in), next marker (out)
1059  * @begin: beginning of the range
1060  * @end: end of the range
1061  *
1062  * Returns whether a next marker has been found (1) or not (0).
1063  * Will return the first marker in the range if the input marker is NULL.
1064  */
1065 int marker_get_iter_range(struct marker **marker, struct marker *begin,
1066         struct marker *end)
1067 {
1068         if (!*marker && begin != end) {
1069                 *marker = begin;
1070                 return 1;
1071         }
1072         if (*marker >= begin && *marker < end)
1073                 return 1;
1074         return 0;
1075 }
1076 //ust// EXPORT_SYMBOL_GPL(marker_get_iter_range);
1077
1078 static void marker_get_iter(struct marker_iter *iter)
1079 {
1080         int found = 0;
1081
1082         /* Core kernel markers */
1083         if (!iter->lib) {
1084                 /* ust FIXME: how come we cannot disable the following line? we shouldn't need core stuff */
1085                 found = marker_get_iter_range(&iter->marker,
1086                                 __start___markers, __stop___markers);
1087                 if (found)
1088                         goto end;
1089         }
1090         /* Markers in modules. */
1091         found = lib_get_iter_markers(iter);
1092 end:
1093         if (!found)
1094                 marker_iter_reset(iter);
1095 }
1096
1097 void marker_iter_start(struct marker_iter *iter)
1098 {
1099         marker_get_iter(iter);
1100 }
1101 //ust// EXPORT_SYMBOL_GPL(marker_iter_start);
1102
1103 void marker_iter_next(struct marker_iter *iter)
1104 {
1105         iter->marker++;
1106         /*
1107          * iter->marker may be invalid because we blindly incremented it.
1108          * Make sure it is valid by marshalling on the markers, getting the
1109          * markers from following modules if necessary.
1110          */
1111         marker_get_iter(iter);
1112 }
1113 //ust// EXPORT_SYMBOL_GPL(marker_iter_next);
1114
1115 void marker_iter_stop(struct marker_iter *iter)
1116 {
1117 }
1118 //ust// EXPORT_SYMBOL_GPL(marker_iter_stop);
1119
1120 void marker_iter_reset(struct marker_iter *iter)
1121 {
1122         iter->lib = NULL;
1123         iter->marker = NULL;
1124 }
1125 //ust// EXPORT_SYMBOL_GPL(marker_iter_reset);
1126
1127 #ifdef CONFIG_MARKERS_USERSPACE
1128 /*
1129  * must be called with current->user_markers_mutex held
1130  */
1131 static void free_user_marker(char __user *state, struct hlist_head *head)
1132 {
1133         struct user_marker *umark;
1134         struct hlist_node *pos, *n;
1135
1136         hlist_for_each_entry_safe(umark, pos, n, head, hlist) {
1137                 if (umark->state == state) {
1138                         hlist_del(&umark->hlist);
1139                         kfree(umark);
1140                 }
1141         }
1142 }
1143
1144 //ust// asmlinkage long sys_marker(char __user *name, char __user *format,
1145 //ust//                 char __user *state, int reg)
1146 //ust// {
1147 //ust//         struct user_marker *umark;
1148 //ust//         long len;
1149 //ust//         struct marker_entry *entry;
1150 //ust//         int ret = 0;
1151 //ust//
1152 //ust//         printk(KERN_DEBUG "Program %s %s marker [%p, %p]\n",
1153 //ust//                 current->comm, reg ? "registers" : "unregisters",
1154 //ust//                 name, state);
1155 //ust//         if (reg) {
1156 //ust//                 umark = kmalloc(sizeof(struct user_marker), GFP_KERNEL);
1157 //ust//                 umark->name[MAX_USER_MARKER_NAME_LEN - 1] = '\0';
1158 //ust//                 umark->format[MAX_USER_MARKER_FORMAT_LEN - 1] = '\0';
1159 //ust//                 umark->state = state;
1160 //ust//                 len = strncpy_from_user(umark->name, name,
1161 //ust//                         MAX_USER_MARKER_NAME_LEN - 1);
1162 //ust//                 if (len < 0) {
1163 //ust//                         ret = -EFAULT;
1164 //ust//                         goto error;
1165 //ust//                 }
1166 //ust//                 len = strncpy_from_user(umark->format, format,
1167 //ust//                         MAX_USER_MARKER_FORMAT_LEN - 1);
1168 //ust//                 if (len < 0) {
1169 //ust//                         ret = -EFAULT;
1170 //ust//                         goto error;
1171 //ust//                 }
1172 //ust//                 printk(KERN_DEBUG "Marker name : %s, format : %s", umark->name,
1173 //ust//                         umark->format);
1174 //ust//                 mutex_lock(&markers_mutex);
1175 //ust//                 entry = get_marker("userspace", umark->name);
1176 //ust//                 if (entry) {
1177 //ust//                         if (entry->format &&
1178 //ust//                                 strcmp(entry->format, umark->format) != 0) {
1179 //ust//                                 printk(" error, wrong format in process %s",
1180 //ust//                                         current->comm);
1181 //ust//                                 ret = -EPERM;
1182 //ust//                                 goto error_unlock;
1183 //ust//                         }
1184 //ust//                         printk(" %s", !!entry->refcount
1185 //ust//                                         ? "enabled" : "disabled");
1186 //ust//                         if (put_user(!!entry->refcount, state)) {
1187 //ust//                                 ret = -EFAULT;
1188 //ust//                                 goto error_unlock;
1189 //ust//                         }
1190 //ust//                         printk("\n");
1191 //ust//                 } else {
1192 //ust//                         printk(" disabled\n");
1193 //ust//                         if (put_user(0, umark->state)) {
1194 //ust//                                 printk(KERN_WARNING
1195 //ust//                                         "Marker in %s caused a fault\n",
1196 //ust//                                         current->comm);
1197 //ust//                                 goto error_unlock;
1198 //ust//                         }
1199 //ust//                 }
1200 //ust//                 mutex_lock(&current->group_leader->user_markers_mutex);
1201 //ust//                 hlist_add_head(&umark->hlist,
1202 //ust//                         &current->group_leader->user_markers);
1203 //ust//                 current->group_leader->user_markers_sequence++;
1204 //ust//                 mutex_unlock(&current->group_leader->user_markers_mutex);
1205 //ust//                 mutex_unlock(&markers_mutex);
1206 //ust//         } else {
1207 //ust//                 mutex_lock(&current->group_leader->user_markers_mutex);
1208 //ust//                 free_user_marker(state,
1209 //ust//                         &current->group_leader->user_markers);
1210 //ust//                 current->group_leader->user_markers_sequence++;
1211 //ust//                 mutex_unlock(&current->group_leader->user_markers_mutex);
1212 //ust//         }
1213 //ust//         goto end;
1214 //ust// error_unlock:
1215 //ust//         mutex_unlock(&markers_mutex);
1216 //ust// error:
1217 //ust//         kfree(umark);
1218 //ust// end:
1219 //ust//         return ret;
1220 //ust// }
1221 //ust//
1222 //ust// /*
1223 //ust//  * Types :
1224 //ust//  * string : 0
1225 //ust//  */
1226 //ust// asmlinkage long sys_trace(int type, uint16_t id,
1227 //ust//                 char __user *ubuf)
1228 //ust// {
1229 //ust//         long ret = -EPERM;
1230 //ust//         char *page;
1231 //ust//         int len;
1232 //ust//
1233 //ust//         switch (type) {
1234 //ust//         case 0: /* String */
1235 //ust//                 ret = -ENOMEM;
1236 //ust//                 page = (char *)__get_free_page(GFP_TEMPORARY);
1237 //ust//                 if (!page)
1238 //ust//                         goto string_out;
1239 //ust//                 len = strncpy_from_user(page, ubuf, PAGE_SIZE);
1240 //ust//                 if (len < 0) {
1241 //ust//                         ret = -EFAULT;
1242 //ust//                         goto string_err;
1243 //ust//                 }
1244 //ust//                 trace_mark(userspace, string, "string %s", page);
1245 //ust// string_err:
1246 //ust//                 free_page((unsigned long) page);
1247 //ust// string_out:
1248 //ust//                 break;
1249 //ust//         default:
1250 //ust//                 break;
1251 //ust//         }
1252 //ust//         return ret;
1253 //ust// }
1254
1255 //ust// static void marker_update_processes(void)
1256 //ust// {
1257 //ust//         struct task_struct *g, *t;
1258 //ust//
1259 //ust//         /*
1260 //ust//          * markers_mutex is taken to protect the p->user_markers read.
1261 //ust//          */
1262 //ust//         mutex_lock(&markers_mutex);
1263 //ust//         read_lock(&tasklist_lock);
1264 //ust//         for_each_process(g) {
1265 //ust//                 WARN_ON(!thread_group_leader(g));
1266 //ust//                 if (hlist_empty(&g->user_markers))
1267 //ust//                         continue;
1268 //ust//                 if (strcmp(g->comm, "testprog") == 0)
1269 //ust//                         printk(KERN_DEBUG "set update pending for testprog\n");
1270 //ust//                 t = g;
1271 //ust//                 do {
1272 //ust//                         /* TODO : implement this thread flag in each arch. */
1273 //ust//                         set_tsk_thread_flag(t, TIF_MARKER_PENDING);
1274 //ust//                 } while ((t = next_thread(t)) != g);
1275 //ust//         }
1276 //ust//         read_unlock(&tasklist_lock);
1277 //ust//         mutex_unlock(&markers_mutex);
1278 //ust// }
1279
1280 /*
1281  * Update current process.
1282  * Note that we have to wait a whole scheduler period before we are sure that
1283  * every running userspace threads have their markers updated.
1284  * (synchronize_sched() can be used to insure this).
1285  */
1286 void marker_update_process(void)
1287 {
1288         struct user_marker *umark;
1289         struct hlist_node *pos;
1290         struct marker_entry *entry;
1291
1292         mutex_lock(&markers_mutex);
1293         mutex_lock(&current->group_leader->user_markers_mutex);
1294         if (strcmp(current->comm, "testprog") == 0)
1295                 printk(KERN_DEBUG "do update pending for testprog\n");
1296         hlist_for_each_entry(umark, pos,
1297                         &current->group_leader->user_markers, hlist) {
1298                 printk(KERN_DEBUG "Updating marker %s in %s\n",
1299                         umark->name, current->comm);
1300                 entry = get_marker("userspace", umark->name);
1301                 if (entry) {
1302                         if (entry->format &&
1303                                 strcmp(entry->format, umark->format) != 0) {
1304                                 printk(KERN_WARNING
1305                                         " error, wrong format in process %s\n",
1306                                         current->comm);
1307                                 break;
1308                         }
1309                         if (put_user(!!entry->refcount, umark->state)) {
1310                                 printk(KERN_WARNING
1311                                         "Marker in %s caused a fault\n",
1312                                         current->comm);
1313                                 break;
1314                         }
1315                 } else {
1316                         if (put_user(0, umark->state)) {
1317                                 printk(KERN_WARNING
1318                                         "Marker in %s caused a fault\n",
1319                                         current->comm);
1320                                 break;
1321                         }
1322                 }
1323         }
1324         clear_thread_flag(TIF_MARKER_PENDING);
1325         mutex_unlock(&current->group_leader->user_markers_mutex);
1326         mutex_unlock(&markers_mutex);
1327 }
1328
1329 /*
1330  * Called at process exit and upon do_execve().
1331  * We assume that when the leader exits, no more references can be done to the
1332  * leader structure by the other threads.
1333  */
1334 void exit_user_markers(struct task_struct *p)
1335 {
1336         struct user_marker *umark;
1337         struct hlist_node *pos, *n;
1338
1339         if (thread_group_leader(p)) {
1340                 mutex_lock(&markers_mutex);
1341                 mutex_lock(&p->user_markers_mutex);
1342                 hlist_for_each_entry_safe(umark, pos, n, &p->user_markers,
1343                         hlist)
1344                     kfree(umark);
1345                 INIT_HLIST_HEAD(&p->user_markers);
1346                 p->user_markers_sequence++;
1347                 mutex_unlock(&p->user_markers_mutex);
1348                 mutex_unlock(&markers_mutex);
1349         }
1350 }
1351
1352 int is_marker_enabled(const char *channel, const char *name)
1353 {
1354         struct marker_entry *entry;
1355
1356         mutex_lock(&markers_mutex);
1357         entry = get_marker(channel, name);
1358         mutex_unlock(&markers_mutex);
1359
1360         return entry && !!entry->refcount;
1361 }
1362 //ust// #endif
1363
1364 int marker_module_notify(struct notifier_block *self,
1365                          unsigned long val, void *data)
1366 {
1367         struct module *mod = data;
1368
1369         switch (val) {
1370         case MODULE_STATE_COMING:
1371                 marker_update_probe_range(mod->markers,
1372                         mod->markers + mod->num_markers);
1373                 break;
1374         case MODULE_STATE_GOING:
1375                 marker_update_probe_range(mod->markers,
1376                         mod->markers + mod->num_markers);
1377                 break;
1378         }
1379         return 0;
1380 }
1381
1382 struct notifier_block marker_module_nb = {
1383         .notifier_call = marker_module_notify,
1384         .priority = 0,
1385 };
1386
1387 //ust// static int init_markers(void)
1388 //ust// {
1389 //ust//         return register_module_notifier(&marker_module_nb);
1390 //ust// }
1391 //ust// __initcall(init_markers);
1392 /* TODO: call marker_module_nb() when a library is linked at runtime (dlopen)? */
1393
1394 #endif /* CONFIG_MODULES */
1395
1396 void ltt_dump_marker_state(struct ltt_trace_struct *trace)
1397 {
1398         struct marker_iter iter;
1399         struct ltt_probe_private_data call_data;
1400         const char *channel;
1401
1402         call_data.trace = trace;
1403         call_data.serializer = NULL;
1404
1405         marker_iter_reset(&iter);
1406         marker_iter_start(&iter);
1407         for (; iter.marker != NULL; marker_iter_next(&iter)) {
1408                 if (!_imv_read(iter.marker->state))
1409                         continue;
1410                 channel = ltt_channels_get_name_from_index(
1411                                 iter.marker->channel_id);
1412                 __trace_mark(0, metadata, core_marker_id,
1413                         &call_data,
1414                         "channel %s name %s event_id %hu "
1415                         "int #1u%zu long #1u%zu pointer #1u%zu "
1416                         "size_t #1u%zu alignment #1u%u",
1417                         channel,
1418                         iter.marker->name,
1419                         iter.marker->event_id,
1420                         sizeof(int), sizeof(long),
1421                         sizeof(void *), sizeof(size_t),
1422                         ltt_get_alignment());
1423                 if (iter.marker->format)
1424                         __trace_mark(0, metadata,
1425                                 core_marker_format,
1426                                 &call_data,
1427                                 "channel %s name %s format %s",
1428                                 channel,
1429                                 iter.marker->name,
1430                                 iter.marker->format);
1431         }
1432         marker_iter_stop(&iter);
1433 }
1434 //ust// EXPORT_SYMBOL_GPL(ltt_dump_marker_state);
1435
1436
1437 static LIST_HEAD(libs);
1438
1439 /*
1440  * Returns 0 if current not found.
1441  * Returns 1 if current found.
1442  */
1443 int lib_get_iter_markers(struct marker_iter *iter)
1444 {
1445         struct lib *iter_lib;
1446         int found = 0;
1447
1448 //ust// mutex_lock(&module_mutex);
1449         list_for_each_entry(iter_lib, &libs, list) {
1450                 if (iter_lib < iter->lib)
1451                         continue;
1452                 else if (iter_lib > iter->lib)
1453                         iter->marker = NULL;
1454                 found = marker_get_iter_range(&iter->marker,
1455                         iter_lib->markers_start,
1456                         iter_lib->markers_start + iter_lib->markers_count);
1457                 if (found) {
1458                         iter->lib = iter_lib;
1459                         break;
1460                 }
1461         }
1462 //ust// mutex_unlock(&module_mutex);
1463         return found;
1464 }
1465
1466 void lib_update_markers(void)
1467 {
1468         struct lib *lib;
1469
1470 //ust// mutex_lock(&module_mutex);
1471         list_for_each_entry(lib, &libs, list)
1472                 marker_update_probe_range(lib->markers_start,
1473                                 lib->markers_start + lib->markers_count);
1474 //ust// mutex_unlock(&module_mutex);
1475 }
1476
1477 static void (*new_marker_cb)(struct marker *) = NULL;
1478
1479 void marker_set_new_marker_cb(void (*cb)(struct marker *))
1480 {
1481         new_marker_cb = cb;
1482 }
1483
1484 static void new_markers(struct marker *start, struct marker *end)
1485 {
1486         if(new_marker_cb) {
1487                 struct marker *m;
1488                 for(m=start; m < end; m++) {
1489                         new_marker_cb(m);
1490                 }
1491         }
1492 }
1493
1494 int marker_register_lib(struct marker *markers_start, int markers_count)
1495 {
1496         struct lib *pl;
1497
1498         pl = (struct lib *) malloc(sizeof(struct lib));
1499
1500         pl->markers_start = markers_start;
1501         pl->markers_count = markers_count;
1502
1503         /* FIXME: maybe protect this with its own mutex? */
1504         lock_markers();
1505         list_add(&pl->list, &libs);
1506         unlock_markers();
1507
1508         new_markers(markers_start, markers_start + markers_count);
1509
1510         /* FIXME: update just the loaded lib */
1511         lib_update_markers();
1512
1513         DBG("just registered a markers section from %p and having %d markers", markers_start, markers_count);
1514
1515         return 0;
1516 }
1517
1518 int marker_unregister_lib(struct marker *markers_start, int markers_count)
1519 {
1520         /*FIXME: implement; but before implementing, marker_register_lib must
1521           have appropriate locking. */
1522
1523         return 0;
1524 }
1525
1526 static int initialized = 0;
1527
1528 void __attribute__((constructor)) init_markers(void)
1529 {
1530         if(!initialized) {
1531                 marker_register_lib(__start___markers, (((long)__stop___markers)-((long)__start___markers))/sizeof(struct marker));
1532                 printf("markers_start: %p, markers_stop: %p\n", __start___markers, __stop___markers);
1533                 initialized = 1;
1534         }
1535 }