libust/tracer.c

   1 /*
   2  * ltt/ltt-tracer.c
   3  *
   4  * (C) Copyright        2005-2008 -
   5  *              Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca)
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  20  *
  21  * Tracing management internal kernel API. Trace buffer allocation/free, tracing
  22  * start/stop.
  23  *
  24  * Author:
  25  *      Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca)
  26  *
  27  * Inspired from LTT :
  28  *  Karim Yaghmour (karim@opersys.com)
  29  *  Tom Zanussi (zanussi@us.ibm.com)
  30  *  Bob Wisniewski (bob@watson.ibm.com)
  31  * And from K42 :
  32  *  Bob Wisniewski (bob@watson.ibm.com)
  33  *
  34  * Changelog:
  35  *  22/09/06, Move to the marker/probes mechanism.
  36  *  19/10/05, Complete lockless mechanism.
  37  *  27/05/05, Modular redesign and rewrite.
  38  */
  39
  40 //ust// #include <linux/time.h>
  41 //ust// #include <linux/ltt-tracer.h>
  42 //ust// #include <linux/module.h>
  43 //ust// #include <linux/string.h>
  44 //ust// #include <linux/slab.h>
  45 //ust// #include <linux/init.h>
  46 //ust// #include <linux/rcupdate.h>
  47 //ust// #include <linux/sched.h>
  48 //ust// #include <linux/bitops.h>
  49 //ust// #include <linux/fs.h>
  50 //ust// #include <linux/cpu.h>
  51 //ust// #include <linux/kref.h>
  52 //ust// #include <linux/delay.h>
  53 //ust// #include <linux/vmalloc.h>
  54 //ust// #include <asm/atomic.h>
  55 #include <urcu-bp.h>
  56 #include <urcu/rculist.h>
  57
  58 #include <ust/kernelcompat.h>
  59 #include "tracercore.h"
  60 #include "tracer.h"
  61 #include "usterr.h"
  62
  63 //ust// static void async_wakeup(unsigned long data);
  64 //ust//
  65 //ust// static DEFINE_TIMER(ltt_async_wakeup_timer, async_wakeup, 0, 0);
  66
  67 /* Default callbacks for modules */
  68 notrace int ltt_filter_control_default(enum ltt_filter_control_msg msg,
  69                 struct ltt_trace_struct *trace)
  70 {
  71         return 0;
  72 }
  73
  74 int ltt_statedump_default(struct ltt_trace_struct *trace)
  75 {
  76         return 0;
  77 }
  78
  79 /* Callbacks for registered modules */
  80
  81 int (*ltt_filter_control_functor)
  82         (enum ltt_filter_control_msg msg, struct ltt_trace_struct *trace) =
  83                                         ltt_filter_control_default;
  84 struct module *ltt_filter_control_owner;
  85
  86 /* These function pointers are protected by a trace activation check */
  87 struct module *ltt_run_filter_owner;
  88 int (*ltt_statedump_functor)(struct ltt_trace_struct *trace) =
  89                                         ltt_statedump_default;
  90 struct module *ltt_statedump_owner;
  91
  92 struct chan_info_struct {
  93         const char *name;
  94         unsigned int def_subbufsize;
  95         unsigned int def_subbufcount;
  96 } chan_infos[] = {
  97         [LTT_CHANNEL_METADATA] = {
  98                 LTT_METADATA_CHANNEL,
  99                 LTT_DEFAULT_SUBBUF_SIZE_LOW,
 100                 LTT_DEFAULT_N_SUBBUFS_LOW,
 101         },
 102         [LTT_CHANNEL_UST] = {
 103                 LTT_UST_CHANNEL,
 104                 LTT_DEFAULT_SUBBUF_SIZE_HIGH,
 105                 LTT_DEFAULT_N_SUBBUFS_HIGH,
 106         },
 107 };
 108
 109 static enum ltt_channels get_channel_type_from_name(const char *name)
 110 {
 111         int i;
 112
 113         if (!name)
 114                 return LTT_CHANNEL_UST;
 115
 116         for (i = 0; i < ARRAY_SIZE(chan_infos); i++)
 117                 if (chan_infos[i].name && !strcmp(name, chan_infos[i].name))
 118                         return (enum ltt_channels)i;
 119
 120         return LTT_CHANNEL_UST;
 121 }
 122
 123 /**
 124  * ltt_module_register - LTT module registration
 125  * @name: module type
 126  * @function: callback to register
 127  * @owner: module which owns the callback
 128  *
 129  * The module calling this registration function must ensure that no
 130  * trap-inducing code will be executed by "function". E.g. vmalloc_sync_all()
 131  * must be called between a vmalloc and the moment the memory is made visible to
 132  * "function". This registration acts as a vmalloc_sync_all. Therefore, only if
 133  * the module allocates virtual memory after its registration must it
 134  * synchronize the TLBs.
 135  */
 136 //ust// int ltt_module_register(enum ltt_module_function name, void *function,
 137 //ust//                 struct module *owner)
 138 //ust// {
 139 //ust//         int ret = 0;
 140 //ust//
 141 //ust//         /*
 142 //ust//          * Make sure no page fault can be triggered by the module about to be
 143 //ust//          * registered. We deal with this here so we don't have to call
 144 //ust//          * vmalloc_sync_all() in each module's init.
 145 //ust//          */
 146 //ust//         vmalloc_sync_all();
 147 //ust//
 148 //ust//         switch (name) {
 149 //ust//         case LTT_FUNCTION_RUN_FILTER:
 150 //ust//                 if (ltt_run_filter_owner != NULL) {
 151 //ust//                         ret = -EEXIST;
 152 //ust//                         goto end;
 153 //ust//                 }
 154 //ust//                 ltt_filter_register((ltt_run_filter_functor)function);
 155 //ust//                 ltt_run_filter_owner = owner;
 156 //ust//                 break;
 157 //ust//         case LTT_FUNCTION_FILTER_CONTROL:
 158 //ust//                 if (ltt_filter_control_owner != NULL) {
 159 //ust//                         ret = -EEXIST;
 160 //ust//                         goto end;
 161 //ust//                 }
 162 //ust//                 ltt_filter_control_functor =
 163 //ust//                         (int (*)(enum ltt_filter_control_msg,
 164 //ust//                         struct ltt_trace_struct *))function;
 165 //ust//                 ltt_filter_control_owner = owner;
 166 //ust//                 break;
 167 //ust//         case LTT_FUNCTION_STATEDUMP:
 168 //ust//                 if (ltt_statedump_owner != NULL) {
 169 //ust//                         ret = -EEXIST;
 170 //ust//                         goto end;
 171 //ust//                 }
 172 //ust//                 ltt_statedump_functor =
 173 //ust//                         (int (*)(struct ltt_trace_struct *))function;
 174 //ust//                 ltt_statedump_owner = owner;
 175 //ust//                 break;
 176 //ust//         }
 177 //ust//
 178 //ust// end:
 179 //ust//
 180 //ust//         return ret;
 181 //ust// }
 182 //ust// EXPORT_SYMBOL_GPL(ltt_module_register);
 183
 184 /**
 185  * ltt_module_unregister - LTT module unregistration
 186  * @name: module type
 187  */
 188 //ust// void ltt_module_unregister(enum ltt_module_function name)
 189 //ust// {
 190 //ust//         switch (name) {
 191 //ust//         case LTT_FUNCTION_RUN_FILTER:
 192 //ust//                 ltt_filter_unregister();
 193 //ust//                 ltt_run_filter_owner = NULL;
 194 //ust//                 /* Wait for preempt sections to finish */
 195 //ust//                 synchronize_sched();
 196 //ust//                 break;
 197 //ust//         case LTT_FUNCTION_FILTER_CONTROL:
 198 //ust//                 ltt_filter_control_functor = ltt_filter_control_default;
 199 //ust//                 ltt_filter_control_owner = NULL;
 200 //ust//                 break;
 201 //ust//         case LTT_FUNCTION_STATEDUMP:
 202 //ust//                 ltt_statedump_functor = ltt_statedump_default;
 203 //ust//                 ltt_statedump_owner = NULL;
 204 //ust//                 break;
 205 //ust//         }
 206 //ust//
 207 //ust// }
 208 //ust// EXPORT_SYMBOL_GPL(ltt_module_unregister);
 209
 210 static LIST_HEAD(ltt_transport_list);
 211
 212 /**
 213  * ltt_transport_register - LTT transport registration
 214  * @transport: transport structure
 215  *
 216  * Registers a transport which can be used as output to extract the data out of
 217  * LTTng. The module calling this registration function must ensure that no
 218  * trap-inducing code will be executed by the transport functions. E.g.
 219  * vmalloc_sync_all() must be called between a vmalloc and the moment the memory
 220  * is made visible to the transport function. This registration acts as a
 221  * vmalloc_sync_all. Therefore, only if the module allocates virtual memory
 222  * after its registration must it synchronize the TLBs.
 223  */
 224 void ltt_transport_register(struct ltt_transport *transport)
 225 {
 226         /*
 227          * Make sure no page fault can be triggered by the module about to be
 228          * registered. We deal with this here so we don't have to call
 229          * vmalloc_sync_all() in each module's init.
 230          */
 231 //ust// vmalloc_sync_all();
 232
 233         ltt_lock_traces();
 234         list_add_tail(&transport->node, &ltt_transport_list);
 235         ltt_unlock_traces();
 236 }
 237 //ust// EXPORT_SYMBOL_GPL(ltt_transport_register);
 238
 239 /**
 240  * ltt_transport_unregister - LTT transport unregistration
 241  * @transport: transport structure
 242  */
 243 void ltt_transport_unregister(struct ltt_transport *transport)
 244 {
 245         ltt_lock_traces();
 246         list_del(&transport->node);
 247         ltt_unlock_traces();
 248 }
 249 //ust// EXPORT_SYMBOL_GPL(ltt_transport_unregister);
 250
 251 static inline int is_channel_overwrite(enum ltt_channels chan,
 252         enum trace_mode mode)
 253 {
 254         switch (mode) {
 255         case LTT_TRACE_NORMAL:
 256                 return 0;
 257         case LTT_TRACE_FLIGHT:
 258                 switch (chan) {
 259                 case LTT_CHANNEL_METADATA:
 260                         return 0;
 261                 default:
 262                         return 1;
 263                 }
 264         case LTT_TRACE_HYBRID:
 265                 switch (chan) {
 266                 case LTT_CHANNEL_METADATA:
 267                         return 0;
 268                 default:
 269                         return 1;
 270                 }
 271         default:
 272                 return 0;
 273         }
 274 }
 275
 276 /**
 277  * ltt_write_trace_header - Write trace header
 278  * @trace: Trace information
 279  * @header: Memory address where the information must be written to
 280  */
 281 void notrace ltt_write_trace_header(struct ltt_trace_struct *trace,
 282                 struct ltt_subbuffer_header *header)
 283 {
 284         header->magic_number = LTT_TRACER_MAGIC_NUMBER;
 285         header->major_version = LTT_TRACER_VERSION_MAJOR;
 286         header->minor_version = LTT_TRACER_VERSION_MINOR;
 287         header->arch_size = sizeof(void *);
 288         header->alignment = ltt_get_alignment();
 289         header->start_time_sec = trace->start_time.tv_sec;
 290         header->start_time_usec = trace->start_time.tv_usec;
 291         header->start_freq = trace->start_freq;
 292         header->freq_scale = trace->freq_scale;
 293 }
 294 //ust// EXPORT_SYMBOL_GPL(ltt_write_trace_header);
 295
 296 static void trace_async_wakeup(struct ltt_trace_struct *trace)
 297 {
 298         int i;
 299         struct ust_channel *chan;
 300
 301         /* Must check each channel for pending read wakeup */
 302         for (i = 0; i < trace->nr_channels; i++) {
 303                 chan = &trace->channels[i];
 304                 if (chan->active)
 305                         trace->ops->wakeup_channel(chan);
 306         }
 307 }
 308
 309 //ust// /* Timer to send async wakeups to the readers */
 310 //ust// static void async_wakeup(unsigned long data)
 311 //ust// {
 312 //ust//         struct ltt_trace_struct *trace;
 313 //ust//
 314 //ust//         /*
 315 //ust//          * PREEMPT_RT does not allow spinlocks to be taken within preempt
 316 //ust//          * disable sections (spinlock taken in wake_up). However, mainline won't
 317 //ust//          * allow mutex to be taken in interrupt context. Ugly.
 318 //ust//          * A proper way to do this would be to turn the timer into a
 319 //ust//          * periodically woken up thread, but it adds to the footprint.
 320 //ust//          */
 321 //ust// #ifndef CONFIG_PREEMPT_RT
 322 //ust//         rcu_read_lock_sched();
 323 //ust// #else
 324 //ust//         ltt_lock_traces();
 325 //ust// #endif
 326 //ust//         list_for_each_entry_rcu(trace, &ltt_traces.head, list) {
 327 //ust//                 trace_async_wakeup(trace);
 328 //ust//         }
 329 //ust// #ifndef CONFIG_PREEMPT_RT
 330 //ust//         rcu_read_unlock_sched();
 331 //ust// #else
 332 //ust//         ltt_unlock_traces();
 333 //ust// #endif
 334 //ust//
 335 //ust//         mod_timer(&ltt_async_wakeup_timer, jiffies + LTT_PERCPU_TIMER_INTERVAL);
 336 //ust// }
 337
 338 /**
 339  * _ltt_trace_find - find a trace by given name.
 340  * trace_name: trace name
 341  *
 342  * Returns a pointer to the trace structure, NULL if not found.
 343  */
 344 struct ltt_trace_struct *_ltt_trace_find(const char *trace_name)
 345 {
 346         struct ltt_trace_struct *trace;
 347
 348         list_for_each_entry(trace, &ltt_traces.head, list)
 349                 if (!strncmp(trace->trace_name, trace_name, NAME_MAX))
 350                         return trace;
 351
 352         return NULL;
 353 }
 354
 355 /* _ltt_trace_find_setup :
 356  * find a trace in setup list by given name.
 357  *
 358  * Returns a pointer to the trace structure, NULL if not found.
 359  */
 360 struct ltt_trace_struct *_ltt_trace_find_setup(const char *trace_name)
 361 {
 362         struct ltt_trace_struct *trace;
 363
 364         list_for_each_entry(trace, &ltt_traces.setup_head, list)
 365                 if (!strncmp(trace->trace_name, trace_name, NAME_MAX))
 366                         return trace;
 367
 368         return NULL;
 369 }
 370 //ust// EXPORT_SYMBOL_GPL(_ltt_trace_find_setup);
 371
 372 /**
 373  * ltt_release_transport - Release an LTT transport
 374  * @kref : reference count on the transport
 375  */
 376 void ltt_release_transport(struct kref *kref)
 377 {
 378 //ust//         struct ltt_trace_struct *trace = container_of(kref,
 379 //ust//                         struct ltt_trace_struct, ltt_transport_kref);
 380 //ust//         trace->ops->remove_dirs(trace);
 381 }
 382 //ust// EXPORT_SYMBOL_GPL(ltt_release_transport);
 383
 384 /**
 385  * ltt_release_trace - Release a LTT trace
 386  * @kref : reference count on the trace
 387  */
 388 void ltt_release_trace(struct kref *kref)
 389 {
 390         struct ltt_trace_struct *trace = container_of(kref,
 391                         struct ltt_trace_struct, kref);
 392         ltt_channels_trace_free(trace->channels);
 393         kfree(trace);
 394 }
 395 //ust// EXPORT_SYMBOL_GPL(ltt_release_trace);
 396
 397 static inline void prepare_chan_size_num(unsigned int *subbuf_size,
 398                                          unsigned int *n_subbufs)
 399 {
 400         *subbuf_size = 1 << get_count_order(*subbuf_size);
 401         *n_subbufs = 1 << get_count_order(*n_subbufs);
 402
 403         /* Subbuf size and number must both be power of two */
 404         WARN_ON(hweight32(*subbuf_size) != 1);
 405         WARN_ON(hweight32(*n_subbufs) != 1);
 406 }
 407
 408 int _ltt_trace_setup(const char *trace_name)
 409 {
 410         int err = 0;
 411         struct ltt_trace_struct *new_trace = NULL;
 412         int metadata_index;
 413         unsigned int chan;
 414         enum ltt_channels chantype;
 415
 416         if (_ltt_trace_find_setup(trace_name)) {
 417                 printk(KERN_ERR "LTT : Trace name %s already used.\n",
 418                                 trace_name);
 419                 err = -EEXIST;
 420                 goto traces_error;
 421         }
 422
 423         if (_ltt_trace_find(trace_name)) {
 424                 printk(KERN_ERR "LTT : Trace name %s already used.\n",
 425                                 trace_name);
 426                 err = -EEXIST;
 427                 goto traces_error;
 428         }
 429
 430         new_trace = kzalloc(sizeof(struct ltt_trace_struct), GFP_KERNEL);
 431         if (!new_trace) {
 432                 printk(KERN_ERR
 433                         "LTT : Unable to allocate memory for trace %s\n",
 434                         trace_name);
 435                 err = -ENOMEM;
 436                 goto traces_error;
 437         }
 438         strncpy(new_trace->trace_name, trace_name, NAME_MAX);
 439         new_trace->channels = ltt_channels_trace_alloc(&new_trace->nr_channels,
 440                                                        0, 1);
 441         if (!new_trace->channels) {
 442                 printk(KERN_ERR
 443                         "LTT : Unable to allocate memory for chaninfo  %s\n",
 444                         trace_name);
 445                 err = -ENOMEM;
 446                 goto trace_free;
 447         }
 448
 449         /*
 450          * Force metadata channel to active, no overwrite.
 451          */
 452         metadata_index = ltt_channels_get_index_from_name("metadata");
 453         WARN_ON(metadata_index < 0);
 454         new_trace->channels[metadata_index].overwrite = 0;
 455         new_trace->channels[metadata_index].active = 1;
 456
 457         /*
 458          * Set hardcoded tracer defaults for some channels
 459          */
 460         for (chan = 0; chan < new_trace->nr_channels; chan++) {
 461                 if (!(new_trace->channels[chan].active))
 462                         continue;
 463
 464                 chantype = get_channel_type_from_name(
 465                         ltt_channels_get_name_from_index(chan));
 466                 new_trace->channels[chan].subbuf_size =
 467                         chan_infos[chantype].def_subbufsize;
 468                 new_trace->channels[chan].subbuf_cnt =
 469                         chan_infos[chantype].def_subbufcount;
 470         }
 471
 472         list_add(&new_trace->list, &ltt_traces.setup_head);
 473         return 0;
 474
 475 trace_free:
 476         kfree(new_trace);
 477 traces_error:
 478         return err;
 479 }
 480 //ust// EXPORT_SYMBOL_GPL(_ltt_trace_setup);
 481
 482
 483 int ltt_trace_setup(const char *trace_name)
 484 {
 485         int ret;
 486         ltt_lock_traces();
 487         ret = _ltt_trace_setup(trace_name);
 488         ltt_unlock_traces();
 489         return ret;
 490 }
 491 //ust// EXPORT_SYMBOL_GPL(ltt_trace_setup);
 492
 493 /* must be called from within a traces lock. */
 494 static void _ltt_trace_free(struct ltt_trace_struct *trace)
 495 {
 496         list_del(&trace->list);
 497         kfree(trace);
 498 }
 499
 500 int ltt_trace_set_type(const char *trace_name, const char *trace_type)
 501 {
 502         int err = 0;
 503         struct ltt_trace_struct *trace;
 504         struct ltt_transport *tran_iter, *transport = NULL;
 505
 506         ltt_lock_traces();
 507
 508         trace = _ltt_trace_find_setup(trace_name);
 509         if (!trace) {
 510                 printk(KERN_ERR "LTT : Trace not found %s\n", trace_name);
 511                 err = -ENOENT;
 512                 goto traces_error;
 513         }
 514
 515         list_for_each_entry(tran_iter, &ltt_transport_list, node) {
 516                 if (!strcmp(tran_iter->name, trace_type)) {
 517                         transport = tran_iter;
 518                         break;
 519                 }
 520         }
 521         if (!transport) {
 522                 printk(KERN_ERR "LTT : Transport %s is not present.\n",
 523                         trace_type);
 524                 err = -EINVAL;
 525                 goto traces_error;
 526         }
 527
 528         trace->transport = transport;
 529
 530 traces_error:
 531         ltt_unlock_traces();
 532         return err;
 533 }
 534 //ust// EXPORT_SYMBOL_GPL(ltt_trace_set_type);
 535
 536 int ltt_trace_set_channel_subbufsize(const char *trace_name,
 537                 const char *channel_name, unsigned int size)
 538 {
 539         int err = 0;
 540         struct ltt_trace_struct *trace;
 541         int index;
 542
 543         ltt_lock_traces();
 544
 545         trace = _ltt_trace_find_setup(trace_name);
 546         if (!trace) {
 547                 printk(KERN_ERR "LTT : Trace not found %s\n", trace_name);
 548                 err = -ENOENT;
 549                 goto traces_error;
 550         }
 551
 552         index = ltt_channels_get_index_from_name(channel_name);
 553         if (index < 0) {
 554                 printk(KERN_ERR "LTT : Channel %s not found\n", channel_name);
 555                 err = -ENOENT;
 556                 goto traces_error;
 557         }
 558         trace->channels[index].subbuf_size = size;
 559
 560 traces_error:
 561         ltt_unlock_traces();
 562         return err;
 563 }
 564 //ust// EXPORT_SYMBOL_GPL(ltt_trace_set_channel_subbufsize);
 565
 566 int ltt_trace_set_channel_subbufcount(const char *trace_name,
 567                 const char *channel_name, unsigned int cnt)
 568 {
 569         int err = 0;
 570         struct ltt_trace_struct *trace;
 571         int index;
 572
 573         ltt_lock_traces();
 574
 575         trace = _ltt_trace_find_setup(trace_name);
 576         if (!trace) {
 577                 printk(KERN_ERR "LTT : Trace not found %s\n", trace_name);
 578                 err = -ENOENT;
 579                 goto traces_error;
 580         }
 581
 582         index = ltt_channels_get_index_from_name(channel_name);
 583         if (index < 0) {
 584                 printk(KERN_ERR "LTT : Channel %s not found\n", channel_name);
 585                 err = -ENOENT;
 586                 goto traces_error;
 587         }
 588         trace->channels[index].subbuf_cnt = cnt;
 589
 590 traces_error:
 591         ltt_unlock_traces();
 592         return err;
 593 }
 594 //ust// EXPORT_SYMBOL_GPL(ltt_trace_set_channel_subbufcount);
 595
 596 int ltt_trace_set_channel_enable(const char *trace_name,
 597                 const char *channel_name, unsigned int enable)
 598 {
 599         int err = 0;
 600         struct ltt_trace_struct *trace;
 601         int index;
 602
 603         ltt_lock_traces();
 604
 605         trace = _ltt_trace_find_setup(trace_name);
 606         if (!trace) {
 607                 printk(KERN_ERR "LTT : Trace not found %s\n", trace_name);
 608                 err = -ENOENT;
 609                 goto traces_error;
 610         }
 611
 612         /*
 613          * Datas in metadata channel(marker info) is necessary to be able to
 614          * read the trace, we always enable this channel.
 615          */
 616         if (!enable && !strcmp(channel_name, "metadata")) {
 617                 printk(KERN_ERR "LTT : Trying to disable metadata channel\n");
 618                 err = -EINVAL;
 619                 goto traces_error;
 620         }
 621
 622         index = ltt_channels_get_index_from_name(channel_name);
 623         if (index < 0) {
 624                 printk(KERN_ERR "LTT : Channel %s not found\n", channel_name);
 625                 err = -ENOENT;
 626                 goto traces_error;
 627         }
 628
 629         trace->channels[index].active = enable;
 630
 631 traces_error:
 632         ltt_unlock_traces();
 633         return err;
 634 }
 635 //ust// EXPORT_SYMBOL_GPL(ltt_trace_set_channel_enable);
 636
 637 int ltt_trace_set_channel_overwrite(const char *trace_name,
 638                 const char *channel_name, unsigned int overwrite)
 639 {
 640         int err = 0;
 641         struct ltt_trace_struct *trace;
 642         int index;
 643
 644         ltt_lock_traces();
 645
 646         trace = _ltt_trace_find_setup(trace_name);
 647         if (!trace) {
 648                 printk(KERN_ERR "LTT : Trace not found %s\n", trace_name);
 649                 err = -ENOENT;
 650                 goto traces_error;
 651         }
 652
 653         /*
 654          * Always put the metadata channel in non-overwrite mode :
 655          * This is a very low traffic channel and it can't afford to have its
 656          * data overwritten : this data (marker info) is necessary to be
 657          * able to read the trace.
 658          */
 659         if (overwrite && !strcmp(channel_name, "metadata")) {
 660                 printk(KERN_ERR "LTT : Trying to set metadata channel to "
 661                                 "overwrite mode\n");
 662                 err = -EINVAL;
 663                 goto traces_error;
 664         }
 665
 666         index = ltt_channels_get_index_from_name(channel_name);
 667         if (index < 0) {
 668                 printk(KERN_ERR "LTT : Channel %s not found\n", channel_name);
 669                 err = -ENOENT;
 670                 goto traces_error;
 671         }
 672
 673         trace->channels[index].overwrite = overwrite;
 674
 675 traces_error:
 676         ltt_unlock_traces();
 677         return err;
 678 }
 679 //ust// EXPORT_SYMBOL_GPL(ltt_trace_set_channel_overwrite);
 680
 681 int ltt_trace_alloc(const char *trace_name)
 682 {
 683         int err = 0;
 684         struct ltt_trace_struct *trace;
 685         unsigned int subbuf_size, subbuf_cnt;
 686 //ust// unsigned long flags;
 687         int chan;
 688         const char *channel_name;
 689
 690         ltt_lock_traces();
 691
 692         trace = _ltt_trace_find_setup(trace_name);
 693         if (!trace) {
 694                 printk(KERN_ERR "LTT : Trace not found %s\n", trace_name);
 695                 err = -ENOENT;
 696                 goto traces_error;
 697         }
 698
 699         kref_init(&trace->kref);
 700         kref_init(&trace->ltt_transport_kref);
 701 //ust// init_waitqueue_head(&trace->kref_wq);
 702         trace->active = 0;
 703 //ust// get_trace_clock();
 704         trace->freq_scale = trace_clock_freq_scale();
 705
 706         if (!trace->transport) {
 707                 printk(KERN_ERR "LTT : Transport is not set.\n");
 708                 err = -EINVAL;
 709                 goto transport_error;
 710         }
 711 //ust// if (!try_module_get(trace->transport->owner)) {
 712 //ust//         printk(KERN_ERR "LTT : Can't lock transport module.\n");
 713 //ust//         err = -ENODEV;
 714 //ust//         goto transport_error;
 715 //ust// }
 716         trace->ops = &trace->transport->ops;
 717
 718 //ust// err = trace->ops->create_dirs(trace);
 719 //ust// if (err) {
 720 //ust//         printk(KERN_ERR "LTT : Can't create dir for trace %s.\n",
 721 //ust//                 trace_name);
 722 //ust//         goto dirs_error;
 723 //ust// }
 724
 725 //ust// local_irq_save(flags);
 726         trace->start_freq = trace_clock_frequency();
 727         trace->start_tsc = trace_clock_read64();
 728         gettimeofday(&trace->start_time, NULL); //ust// changed
 729 //ust// local_irq_restore(flags);
 730
 731         for (chan = 0; chan < trace->nr_channels; chan++) {
 732                 if (!(trace->channels[chan].active))
 733                         continue;
 734
 735                 channel_name = ltt_channels_get_name_from_index(chan);
 736                 WARN_ON(!channel_name);
 737                 subbuf_size = trace->channels[chan].subbuf_size;
 738                 subbuf_cnt = trace->channels[chan].subbuf_cnt;
 739                 prepare_chan_size_num(&subbuf_size, &subbuf_cnt);
 740                 err = trace->ops->create_channel(trace_name, trace,
 741                                 channel_name,
 742                                 &trace->channels[chan],
 743                                 subbuf_size,
 744                                 subbuf_cnt,
 745                                 trace->channels[chan].overwrite);
 746                 if (err != 0) {
 747                         printk(KERN_ERR "LTT : Can't create channel %s.\n",
 748                                 channel_name);
 749                         goto create_channel_error;
 750                 }
 751         }
 752
 753         list_del(&trace->list);
 754 //ust// if (list_empty(&ltt_traces.head)) {
 755 //ust//         mod_timer(&ltt_async_wakeup_timer,
 756 //ust//                         jiffies + LTT_PERCPU_TIMER_INTERVAL);
 757 //ust//         set_kernel_trace_flag_all_tasks();
 758 //ust// }
 759         list_add_rcu(&trace->list, &ltt_traces.head);
 760 //ust// synchronize_sched();
 761
 762         ltt_unlock_traces();
 763
 764         return 0;
 765
 766 create_channel_error:
 767         for (chan--; chan >= 0; chan--)
 768                 if (trace->channels[chan].active)
 769                         trace->ops->remove_channel(&trace->channels[chan]);
 770
 771 //ust// dirs_error:
 772 //ust// module_put(trace->transport->owner);
 773 transport_error:
 774 //ust// put_trace_clock();
 775 traces_error:
 776         ltt_unlock_traces();
 777         return err;
 778 }
 779 //ust// EXPORT_SYMBOL_GPL(ltt_trace_alloc);
 780
 781 /*
 782  * It is worked as a wrapper for current version of ltt_control.ko.
 783  * We will make a new ltt_control based on debugfs, and control each channel's
 784  * buffer.
 785  */
 786 //ust// static int ltt_trace_create(const char *trace_name, const char *trace_type,
 787 //ust//                 enum trace_mode mode,
 788 //ust//                 unsigned int subbuf_size_low, unsigned int n_subbufs_low,
 789 //ust//                 unsigned int subbuf_size_med, unsigned int n_subbufs_med,
 790 //ust//                 unsigned int subbuf_size_high, unsigned int n_subbufs_high)
 791 //ust// {
 792 //ust//         int err = 0;
 793 //ust//
 794 //ust//         err = ltt_trace_setup(trace_name);
 795 //ust//         if (IS_ERR_VALUE(err))
 796 //ust//                 return err;
 797 //ust//
 798 //ust//         err = ltt_trace_set_type(trace_name, trace_type);
 799 //ust//         if (IS_ERR_VALUE(err))
 800 //ust//                 return err;
 801 //ust//
 802 //ust//         err = ltt_trace_alloc(trace_name);
 803 //ust//         if (IS_ERR_VALUE(err))
 804 //ust//                 return err;
 805 //ust//
 806 //ust//         return err;
 807 //ust// }
 808
 809 /* Must be called while sure that trace is in the list. */
 810 static int _ltt_trace_destroy(struct ltt_trace_struct *trace)
 811 {
 812         int err = -EPERM;
 813
 814         if (trace == NULL) {
 815                 err = -ENOENT;
 816                 goto traces_error;
 817         }
 818         if (trace->active) {
 819                 printk(KERN_ERR
 820                         "LTT : Can't destroy trace %s : tracer is active\n",
 821                         trace->trace_name);
 822                 err = -EBUSY;
 823                 goto active_error;
 824         }
 825         /* Everything went fine */
 826         list_del_rcu(&trace->list);
 827         synchronize_rcu();
 828         if (list_empty(&ltt_traces.head)) {
 829 //ust//         clear_kernel_trace_flag_all_tasks();
 830                 /*
 831                  * We stop the asynchronous delivery of reader wakeup, but
 832                  * we must make one last check for reader wakeups pending
 833                  * later in __ltt_trace_destroy.
 834                  */
 835 //ust//         del_timer_sync(&ltt_async_wakeup_timer);
 836         }
 837         return 0;
 838
 839         /* error handling */
 840 active_error:
 841 traces_error:
 842         return err;
 843 }
 844
 845 /* Sleepable part of the destroy */
 846 static void __ltt_trace_destroy(struct ltt_trace_struct *trace)
 847 {
 848         int i;
 849         struct ust_channel *chan;
 850
 851         for (i = 0; i < trace->nr_channels; i++) {
 852                 chan = &trace->channels[i];
 853                 if (chan->active)
 854                         trace->ops->finish_channel(chan);
 855         }
 856
 857         return; /* FIXME: temporary for ust */
 858 //ust// flush_scheduled_work();
 859
 860         /*
 861          * The currently destroyed trace is not in the trace list anymore,
 862          * so it's safe to call the async wakeup ourself. It will deliver
 863          * the last subbuffers.
 864          */
 865         trace_async_wakeup(trace);
 866
 867         for (i = 0; i < trace->nr_channels; i++) {
 868                 chan = &trace->channels[i];
 869                 if (chan->active)
 870                         trace->ops->remove_channel(chan);
 871         }
 872
 873         kref_put(&trace->ltt_transport_kref, ltt_release_transport);
 874
 875 //ust// module_put(trace->transport->owner);
 876
 877         /*
 878          * Wait for lttd readers to release the files, therefore making sure
 879          * the last subbuffers have been read.
 880          */
 881 //ust// if (atomic_read(&trace->kref.refcount) > 1) {
 882 //ust//         int ret = 0;
 883 //ust//         __wait_event_interruptible(trace->kref_wq,
 884 //ust//                 (atomic_read(&trace->kref.refcount) == 1), ret);
 885 //ust// }
 886         kref_put(&trace->kref, ltt_release_trace);
 887 }
 888
 889 int ltt_trace_destroy(const char *trace_name)
 890 {
 891         int err = 0;
 892         struct ltt_trace_struct *trace;
 893
 894         ltt_lock_traces();
 895
 896         trace = _ltt_trace_find(trace_name);
 897         if (trace) {
 898                 err = _ltt_trace_destroy(trace);
 899                 if (err)
 900                         goto error;
 901
 902                 ltt_unlock_traces();
 903
 904                 __ltt_trace_destroy(trace);
 905 //ust//         put_trace_clock();
 906
 907                 return 0;
 908         }
 909
 910         trace = _ltt_trace_find_setup(trace_name);
 911         if (trace) {
 912                 _ltt_trace_free(trace);
 913                 ltt_unlock_traces();
 914                 return 0;
 915         }
 916
 917         err = -ENOENT;
 918
 919         /* Error handling */
 920 error:
 921         ltt_unlock_traces();
 922         return err;
 923 }
 924 //ust// EXPORT_SYMBOL_GPL(ltt_trace_destroy);
 925
 926 /* must be called from within a traces lock. */
 927 static int _ltt_trace_start(struct ltt_trace_struct *trace)
 928 {
 929         int err = 0;
 930
 931         if (trace == NULL) {
 932                 err = -ENOENT;
 933                 goto traces_error;
 934         }
 935         if (trace->active)
 936                 printk(KERN_INFO "LTT : Tracing already active for trace %s\n",
 937                                 trace->trace_name);
 938 //ust// if (!try_module_get(ltt_run_filter_owner)) {
 939 //ust//         err = -ENODEV;
 940 //ust//         printk(KERN_ERR "LTT : Can't lock filter module.\n");
 941 //ust//         goto get_ltt_run_filter_error;
 942 //ust// }
 943         trace->active = 1;
 944         /* Read by trace points without protection : be careful */
 945         ltt_traces.num_active_traces++;
 946         return err;
 947
 948         /* error handling */
 949 //ust// get_ltt_run_filter_error:
 950 traces_error:
 951         return err;
 952 }
 953
 954 int ltt_trace_start(const char *trace_name)
 955 {
 956         int err = 0;
 957         struct ltt_trace_struct *trace;
 958
 959         ltt_lock_traces();
 960
 961         trace = _ltt_trace_find(trace_name);
 962         err = _ltt_trace_start(trace);
 963         if (err)
 964                 goto no_trace;
 965
 966         ltt_unlock_traces();
 967
 968         /*
 969          * Call the kernel state dump.
 970          * Events will be mixed with real kernel events, it's ok.
 971          * Notice that there is no protection on the trace : that's exactly
 972          * why we iterate on the list and check for trace equality instead of
 973          * directly using this trace handle inside the logging function.
 974          */
 975
 976         ltt_dump_marker_state(trace);
 977
 978 //ust// if (!try_module_get(ltt_statedump_owner)) {
 979 //ust//         err = -ENODEV;
 980 //ust//         printk(KERN_ERR
 981 //ust//                 "LTT : Can't lock state dump module.\n");
 982 //ust// } else {
 983                 ltt_statedump_functor(trace);
 984 //ust//         module_put(ltt_statedump_owner);
 985 //ust// }
 986
 987         return err;
 988
 989         /* Error handling */
 990 no_trace:
 991         ltt_unlock_traces();
 992         return err;
 993 }
 994 //ust// EXPORT_SYMBOL_GPL(ltt_trace_start);
 995
 996 /* must be called from within traces lock */
 997 static int _ltt_trace_stop(struct ltt_trace_struct *trace)
 998 {
 999         int err = -EPERM;
1000
1001         if (trace == NULL) {
1002                 err = -ENOENT;
1003                 goto traces_error;
1004         }
1005         if (!trace->active)
1006                 printk(KERN_INFO "LTT : Tracing not active for trace %s\n",
1007                                 trace->trace_name);
1008         if (trace->active) {
1009                 trace->active = 0;
1010                 ltt_traces.num_active_traces--;
1011 //ust//         synchronize_sched(); /* Wait for each tracing to be finished */
1012         }
1013 //ust// module_put(ltt_run_filter_owner);
1014         /* Everything went fine */
1015         return 0;
1016
1017         /* Error handling */
1018 traces_error:
1019         return err;
1020 }
1021
1022 int ltt_trace_stop(const char *trace_name)
1023 {
1024         int err = 0;
1025         struct ltt_trace_struct *trace;
1026
1027         ltt_lock_traces();
1028         trace = _ltt_trace_find(trace_name);
1029         err = _ltt_trace_stop(trace);
1030         ltt_unlock_traces();
1031         return err;
1032 }
1033 //ust// EXPORT_SYMBOL_GPL(ltt_trace_stop);
1034
1035 /**
1036  * ltt_control - Trace control in-kernel API
1037  * @msg: Action to perform
1038  * @trace_name: Trace on which the action must be done
1039  * @trace_type: Type of trace (normal, flight, hybrid)
1040  * @args: Arguments specific to the action
1041  */
1042 //ust// int ltt_control(enum ltt_control_msg msg, const char *trace_name,
1043 //ust//                 const char *trace_type, union ltt_control_args args)
1044 //ust// {
1045 //ust//         int err = -EPERM;
1046 //ust//
1047 //ust//         printk(KERN_ALERT "ltt_control : trace %s\n", trace_name);
1048 //ust//         switch (msg) {
1049 //ust//         case LTT_CONTROL_START:
1050 //ust//                 printk(KERN_DEBUG "Start tracing %s\n", trace_name);
1051 //ust//                 err = ltt_trace_start(trace_name);
1052 //ust//                 break;
1053 //ust//         case LTT_CONTROL_STOP:
1054 //ust//                 printk(KERN_DEBUG "Stop tracing %s\n", trace_name);
1055 //ust//                 err = ltt_trace_stop(trace_name);
1056 //ust//                 break;
1057 //ust//         case LTT_CONTROL_CREATE_TRACE:
1058 //ust//                 printk(KERN_DEBUG "Creating trace %s\n", trace_name);
1059 //ust//                 err = ltt_trace_create(trace_name, trace_type,
1060 //ust//                         args.new_trace.mode,
1061 //ust//                         args.new_trace.subbuf_size_low,
1062 //ust//                         args.new_trace.n_subbufs_low,
1063 //ust//                         args.new_trace.subbuf_size_med,
1064 //ust//                         args.new_trace.n_subbufs_med,
1065 //ust//                         args.new_trace.subbuf_size_high,
1066 //ust//                         args.new_trace.n_subbufs_high);
1067 //ust//                 break;
1068 //ust//         case LTT_CONTROL_DESTROY_TRACE:
1069 //ust//                 printk(KERN_DEBUG "Destroying trace %s\n", trace_name);
1070 //ust//                 err = ltt_trace_destroy(trace_name);
1071 //ust//                 break;
1072 //ust//         }
1073 //ust//         return err;
1074 //ust// }
1075 //ust// EXPORT_SYMBOL_GPL(ltt_control);
1076
1077 /**
1078  * ltt_filter_control - Trace filter control in-kernel API
1079  * @msg: Action to perform on the filter
1080  * @trace_name: Trace on which the action must be done
1081  */
1082 int ltt_filter_control(enum ltt_filter_control_msg msg, const char *trace_name)
1083 {
1084         int err;
1085         struct ltt_trace_struct *trace;
1086
1087         printk(KERN_DEBUG "ltt_filter_control : trace %s\n", trace_name);
1088         ltt_lock_traces();
1089         trace = _ltt_trace_find(trace_name);
1090         if (trace == NULL) {
1091                 printk(KERN_ALERT
1092                         "Trace does not exist. Cannot proxy control request\n");
1093                 err = -ENOENT;
1094                 goto trace_error;
1095         }
1096 //ust// if (!try_module_get(ltt_filter_control_owner)) {
1097 //ust//         err = -ENODEV;
1098 //ust//         goto get_module_error;
1099 //ust// }
1100         switch (msg) {
1101         case LTT_FILTER_DEFAULT_ACCEPT:
1102                 printk(KERN_DEBUG
1103                         "Proxy filter default accept %s\n", trace_name);
1104                 err = (*ltt_filter_control_functor)(msg, trace);
1105                 break;
1106         case LTT_FILTER_DEFAULT_REJECT:
1107                 printk(KERN_DEBUG
1108                         "Proxy filter default reject %s\n", trace_name);
1109                 err = (*ltt_filter_control_functor)(msg, trace);
1110                 break;
1111         default:
1112                 err = -EPERM;
1113         }
1114 //ust// module_put(ltt_filter_control_owner);
1115
1116 //ust// get_module_error:
1117 trace_error:
1118         ltt_unlock_traces();
1119         return err;
1120 }
1121 //ust// EXPORT_SYMBOL_GPL(ltt_filter_control);
1122
1123 //ust// int __init ltt_init(void)
1124 //ust// {
1125 //ust//         /* Make sure no page fault can be triggered by this module */
1126 //ust//         vmalloc_sync_all();
1127 //ust//         return 0;
1128 //ust// }
1129
1130 //ust// module_init(ltt_init)
1131
1132 //ust// static void __exit ltt_exit(void)
1133 //ust// {
1134 //ust//         struct ltt_trace_struct *trace;
1135 //ust//         struct list_head *pos, *n;
1136 //ust//
1137 //ust//         ltt_lock_traces();
1138 //ust//         /* Stop each trace, currently being read by RCU read-side */
1139 //ust//         list_for_each_entry_rcu(trace, &ltt_traces.head, list)
1140 //ust//                 _ltt_trace_stop(trace);
1141 //ust//         /* Wait for quiescent state. Readers have preemption disabled. */
1142 //ust//         synchronize_sched();
1143 //ust//         /* Safe iteration is now permitted. It does not have to be RCU-safe
1144 //ust//          * because no readers are left. */
1145 //ust//         list_for_each_safe(pos, n, &ltt_traces.head) {
1146 //ust//                 trace = container_of(pos, struct ltt_trace_struct, list);
1147 //ust//                 /* _ltt_trace_destroy does a synchronize_sched() */
1148 //ust//                 _ltt_trace_destroy(trace);
1149 //ust//                 __ltt_trace_destroy(trace);
1150 //ust//         }
1151 //ust//         /* free traces in pre-alloc status */
1152 //ust//         list_for_each_safe(pos, n, &ltt_traces.setup_head) {
1153 //ust//                 trace = container_of(pos, struct ltt_trace_struct, list);
1154 //ust//                 _ltt_trace_free(trace);
1155 //ust//         }
1156 //ust//
1157 //ust//         ltt_unlock_traces();
1158 //ust// }
1159
1160 //ust// module_exit(ltt_exit)
1161
1162 //ust// MODULE_LICENSE("GPL");
1163 //ust// MODULE_AUTHOR("Mathieu Desnoyers");
1164 //ust// MODULE_DESCRIPTION("Linux Trace Toolkit Next Generation Tracer Kernel API");