kernel/trace/ftrace.c

   1 /*
   2  * Infrastructure for profiling code inserted by 'gcc -pg'.
   3  *
   4  * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
   5  * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
   6  *
   7  * Originally ported from the -rt patch by:
   8  *   Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
   9  *
  10  * Based on code in the latency_tracer, that is:
  11  *
  12  *  Copyright (C) 2004-2006 Ingo Molnar
  13  *  Copyright (C) 2004 William Lee Irwin III
  14  */
  15
  16 #include <linux/stop_machine.h>
  17 #include <linux/clocksource.h>
  18 #include <linux/kallsyms.h>
  19 #include <linux/seq_file.h>
  20 #include <linux/debugfs.h>
  21 #include <linux/kthread.h>
  22 #include <linux/hardirq.h>
  23 #include <linux/ftrace.h>
  24 #include <linux/uaccess.h>
  25 #include <linux/sysctl.h>
  26 #include <linux/hash.h>
  27 #include <linux/ctype.h>
  28 #include <linux/list.h>
  29
  30 #include "trace.h"
  31
  32 int ftrace_enabled;
  33 static int last_ftrace_enabled;
  34
  35 static DEFINE_SPINLOCK(ftrace_lock);
  36 static DEFINE_MUTEX(ftrace_sysctl_lock);
  37
  38 static struct ftrace_ops ftrace_list_end __read_mostly =
  39 {
  40         .func = ftrace_stub,
  41 };
  42
  43 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
  44 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
  45
  46 /* mcount is defined per arch in assembly */
  47 EXPORT_SYMBOL(mcount);
  48
  49 notrace void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
  50 {
  51         struct ftrace_ops *op = ftrace_list;
  52
  53         /* in case someone actually ports this to alpha! */
  54         read_barrier_depends();
  55
  56         while (op != &ftrace_list_end) {
  57                 /* silly alpha */
  58                 read_barrier_depends();
  59                 op->func(ip, parent_ip);
  60                 op = op->next;
  61         };
  62 }
  63
  64 /**
  65  * clear_ftrace_function - reset the ftrace function
  66  *
  67  * This NULLs the ftrace function and in essence stops
  68  * tracing.  There may be lag
  69  */
  70 void clear_ftrace_function(void)
  71 {
  72         ftrace_trace_function = ftrace_stub;
  73 }
  74
  75 static int notrace __register_ftrace_function(struct ftrace_ops *ops)
  76 {
  77         /* Should never be called by interrupts */
  78         spin_lock(&ftrace_lock);
  79
  80         ops->next = ftrace_list;
  81         /*
  82          * We are entering ops into the ftrace_list but another
  83          * CPU might be walking that list. We need to make sure
  84          * the ops->next pointer is valid before another CPU sees
  85          * the ops pointer included into the ftrace_list.
  86          */
  87         smp_wmb();
  88         ftrace_list = ops;
  89
  90         if (ftrace_enabled) {
  91                 /*
  92                  * For one func, simply call it directly.
  93                  * For more than one func, call the chain.
  94                  */
  95                 if (ops->next == &ftrace_list_end)
  96                         ftrace_trace_function = ops->func;
  97                 else
  98                         ftrace_trace_function = ftrace_list_func;
  99         }
 100
 101         spin_unlock(&ftrace_lock);
 102
 103         return 0;
 104 }
 105
 106 static int notrace __unregister_ftrace_function(struct ftrace_ops *ops)
 107 {
 108         struct ftrace_ops **p;
 109         int ret = 0;
 110
 111         spin_lock(&ftrace_lock);
 112
 113         /*
 114          * If we are removing the last function, then simply point
 115          * to the ftrace_stub.
 116          */
 117         if (ftrace_list == ops && ops->next == &ftrace_list_end) {
 118                 ftrace_trace_function = ftrace_stub;
 119                 ftrace_list = &ftrace_list_end;
 120                 goto out;
 121         }
 122
 123         for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
 124                 if (*p == ops)
 125                         break;
 126
 127         if (*p != ops) {
 128                 ret = -1;
 129                 goto out;
 130         }
 131
 132         *p = (*p)->next;
 133
 134         if (ftrace_enabled) {
 135                 /* If we only have one func left, then call that directly */
 136                 if (ftrace_list == &ftrace_list_end ||
 137                     ftrace_list->next == &ftrace_list_end)
 138                         ftrace_trace_function = ftrace_list->func;
 139         }
 140
 141  out:
 142         spin_unlock(&ftrace_lock);
 143
 144         return ret;
 145 }
 146
 147 #ifdef CONFIG_DYNAMIC_FTRACE
 148
 149 static struct task_struct *ftraced_task;
 150 static DECLARE_WAIT_QUEUE_HEAD(ftraced_waiters);
 151 static unsigned long ftraced_iteration_counter;
 152
 153 enum {
 154         FTRACE_ENABLE_CALLS             = (1 << 0),
 155         FTRACE_DISABLE_CALLS            = (1 << 1),
 156         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 157         FTRACE_ENABLE_MCOUNT            = (1 << 3),
 158         FTRACE_DISABLE_MCOUNT           = (1 << 4),
 159 };
 160
 161 static int ftrace_filtered;
 162
 163 static struct hlist_head ftrace_hash[FTRACE_HASHSIZE];
 164
 165 static DEFINE_PER_CPU(int, ftrace_shutdown_disable_cpu);
 166
 167 static DEFINE_SPINLOCK(ftrace_shutdown_lock);
 168 static DEFINE_MUTEX(ftraced_lock);
 169 static DEFINE_MUTEX(ftrace_filter_lock);
 170
 171 struct ftrace_page {
 172         struct ftrace_page      *next;
 173         int                     index;
 174         struct dyn_ftrace       records[];
 175 } __attribute__((packed));
 176
 177 #define ENTRIES_PER_PAGE \
 178   ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
 179
 180 /* estimate from running different kernels */
 181 #define NR_TO_INIT              10000
 182
 183 static struct ftrace_page       *ftrace_pages_start;
 184 static struct ftrace_page       *ftrace_pages;
 185
 186 static int ftraced_trigger;
 187 static int ftraced_suspend;
 188
 189 static int ftrace_record_suspend;
 190
 191 static struct dyn_ftrace *ftrace_free_records;
 192
 193 static inline int
 194 notrace ftrace_ip_in_hash(unsigned long ip, unsigned long key)
 195 {
 196         struct dyn_ftrace *p;
 197         struct hlist_node *t;
 198         int found = 0;
 199
 200         hlist_for_each_entry(p, t, &ftrace_hash[key], node) {
 201                 if (p->ip == ip) {
 202                         found = 1;
 203                         break;
 204                 }
 205         }
 206
 207         return found;
 208 }
 209
 210 static inline void notrace
 211 ftrace_add_hash(struct dyn_ftrace *node, unsigned long key)
 212 {
 213         hlist_add_head(&node->node, &ftrace_hash[key]);
 214 }
 215
 216 static notrace void ftrace_free_rec(struct dyn_ftrace *rec)
 217 {
 218         /* no locking, only called from kstop_machine */
 219
 220         rec->ip = (unsigned long)ftrace_free_records;
 221         ftrace_free_records = rec;
 222         rec->flags |= FTRACE_FL_FREE;
 223 }
 224
 225 static notrace struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
 226 {
 227         struct dyn_ftrace *rec;
 228
 229         /* First check for freed records */
 230         if (ftrace_free_records) {
 231                 rec = ftrace_free_records;
 232
 233                 /* todo, disable tracing altogether on this warning */
 234                 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
 235                         WARN_ON_ONCE(1);
 236                         ftrace_free_records = NULL;
 237                         return NULL;
 238                 }
 239
 240                 ftrace_free_records = (void *)rec->ip;
 241                 memset(rec, 0, sizeof(*rec));
 242                 return rec;
 243         }
 244
 245         if (ftrace_pages->index == ENTRIES_PER_PAGE) {
 246                 if (!ftrace_pages->next)
 247                         return NULL;
 248                 ftrace_pages = ftrace_pages->next;
 249         }
 250
 251         return &ftrace_pages->records[ftrace_pages->index++];
 252 }
 253
 254 static void notrace
 255 ftrace_record_ip(unsigned long ip)
 256 {
 257         struct dyn_ftrace *node;
 258         unsigned long flags;
 259         unsigned long key;
 260         int resched;
 261         int atomic;
 262
 263         if (!ftrace_enabled)
 264                 return;
 265
 266         resched = need_resched();
 267         preempt_disable_notrace();
 268
 269         /* We simply need to protect against recursion */
 270         __get_cpu_var(ftrace_shutdown_disable_cpu)++;
 271         if (__get_cpu_var(ftrace_shutdown_disable_cpu) != 1)
 272                 goto out;
 273
 274         if (unlikely(ftrace_record_suspend))
 275                 goto out;
 276
 277         key = hash_long(ip, FTRACE_HASHBITS);
 278
 279         WARN_ON_ONCE(key >= FTRACE_HASHSIZE);
 280
 281         if (ftrace_ip_in_hash(ip, key))
 282                 goto out;
 283
 284         atomic = irqs_disabled();
 285
 286         spin_lock_irqsave(&ftrace_shutdown_lock, flags);
 287
 288         /* This ip may have hit the hash before the lock */
 289         if (ftrace_ip_in_hash(ip, key))
 290                 goto out_unlock;
 291
 292         /*
 293          * There's a slight race that the ftraced will update the
 294          * hash and reset here. If it is already converted, skip it.
 295          */
 296         if (ftrace_ip_converted(ip))
 297                 goto out_unlock;
 298
 299         node = ftrace_alloc_dyn_node(ip);
 300         if (!node)
 301                 goto out_unlock;
 302
 303         node->ip = ip;
 304
 305         ftrace_add_hash(node, key);
 306
 307         ftraced_trigger = 1;
 308
 309  out_unlock:
 310         spin_unlock_irqrestore(&ftrace_shutdown_lock, flags);
 311  out:
 312         __get_cpu_var(ftrace_shutdown_disable_cpu)--;
 313
 314         /* prevent recursion with scheduler */
 315         if (resched)
 316                 preempt_enable_no_resched_notrace();
 317         else
 318                 preempt_enable_notrace();
 319 }
 320
 321 #define FTRACE_ADDR ((long)(&ftrace_caller))
 322 #define MCOUNT_ADDR ((long)(&mcount))
 323
 324 static void notrace
 325 __ftrace_replace_code(struct dyn_ftrace *rec,
 326                       unsigned char *old, unsigned char *new, int enable)
 327 {
 328         unsigned long ip;
 329         int failed;
 330
 331         ip = rec->ip;
 332
 333         if (ftrace_filtered && enable) {
 334                 unsigned long fl;
 335                 /*
 336                  * If filtering is on:
 337                  *
 338                  * If this record is set to be filtered and
 339                  * is enabled then do nothing.
 340                  *
 341                  * If this record is set to be filtered and
 342                  * it is not enabled, enable it.
 343                  *
 344                  * If this record is not set to be filtered
 345                  * and it is not enabled do nothing.
 346                  *
 347                  * If this record is not set to be filtered and
 348                  * it is enabled, disable it.
 349                  */
 350                 fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED);
 351
 352                 if ((fl ==  (FTRACE_FL_FILTER | FTRACE_FL_ENABLED)) ||
 353                     (fl == 0))
 354                         return;
 355
 356                 /*
 357                  * If it is enabled disable it,
 358                  * otherwise enable it!
 359                  */
 360                 if (fl == FTRACE_FL_ENABLED) {
 361                         /* swap new and old */
 362                         new = old;
 363                         old = ftrace_call_replace(ip, FTRACE_ADDR);
 364                         rec->flags &= ~FTRACE_FL_ENABLED;
 365                 } else {
 366                         new = ftrace_call_replace(ip, FTRACE_ADDR);
 367                         rec->flags |= FTRACE_FL_ENABLED;
 368                 }
 369         } else {
 370
 371                 if (enable)
 372                         new = ftrace_call_replace(ip, FTRACE_ADDR);
 373                 else
 374                         old = ftrace_call_replace(ip, FTRACE_ADDR);
 375
 376                 if (enable) {
 377                         if (rec->flags & FTRACE_FL_ENABLED)
 378                                 return;
 379                         rec->flags |= FTRACE_FL_ENABLED;
 380                 } else {
 381                         if (!(rec->flags & FTRACE_FL_ENABLED))
 382                                 return;
 383                         rec->flags &= ~FTRACE_FL_ENABLED;
 384                 }
 385         }
 386
 387         failed = ftrace_modify_code(ip, old, new);
 388         if (failed) {
 389                 unsigned long key;
 390                 /* It is possible that the function hasn't been converted yet */
 391                 key = hash_long(ip, FTRACE_HASHBITS);
 392                 if (!ftrace_ip_in_hash(ip, key)) {
 393                         rec->flags |= FTRACE_FL_FAILED;
 394                         ftrace_free_rec(rec);
 395                 }
 396
 397         }
 398 }
 399
 400 static void notrace ftrace_replace_code(int enable)
 401 {
 402         unsigned char *new = NULL, *old = NULL;
 403         struct dyn_ftrace *rec;
 404         struct ftrace_page *pg;
 405         int i;
 406
 407         if (enable)
 408                 old = ftrace_nop_replace();
 409         else
 410                 new = ftrace_nop_replace();
 411
 412         for (pg = ftrace_pages_start; pg; pg = pg->next) {
 413                 for (i = 0; i < pg->index; i++) {
 414                         rec = &pg->records[i];
 415
 416                         /* don't modify code that has already faulted */
 417                         if (rec->flags & FTRACE_FL_FAILED)
 418                                 continue;
 419
 420                         __ftrace_replace_code(rec, old, new, enable);
 421                 }
 422         }
 423 }
 424
 425 static notrace void ftrace_shutdown_replenish(void)
 426 {
 427         if (ftrace_pages->next)
 428                 return;
 429
 430         /* allocate another page */
 431         ftrace_pages->next = (void *)get_zeroed_page(GFP_KERNEL);
 432 }
 433
 434 static notrace void
 435 ftrace_code_disable(struct dyn_ftrace *rec)
 436 {
 437         unsigned long ip;
 438         unsigned char *nop, *call;
 439         int failed;
 440
 441         ip = rec->ip;
 442
 443         nop = ftrace_nop_replace();
 444         call = ftrace_call_replace(ip, MCOUNT_ADDR);
 445
 446         failed = ftrace_modify_code(ip, call, nop);
 447         if (failed) {
 448                 rec->flags |= FTRACE_FL_FAILED;
 449                 ftrace_free_rec(rec);
 450         }
 451 }
 452
 453 static int notrace __ftrace_modify_code(void *data)
 454 {
 455         unsigned long addr;
 456         int *command = data;
 457
 458         if (*command & FTRACE_ENABLE_CALLS)
 459                 ftrace_replace_code(1);
 460         else if (*command & FTRACE_DISABLE_CALLS)
 461                 ftrace_replace_code(0);
 462
 463         if (*command & FTRACE_UPDATE_TRACE_FUNC)
 464                 ftrace_update_ftrace_func(ftrace_trace_function);
 465
 466         if (*command & FTRACE_ENABLE_MCOUNT) {
 467                 addr = (unsigned long)ftrace_record_ip;
 468                 ftrace_mcount_set(&addr);
 469         } else if (*command & FTRACE_DISABLE_MCOUNT) {
 470                 addr = (unsigned long)ftrace_stub;
 471                 ftrace_mcount_set(&addr);
 472         }
 473
 474         return 0;
 475 }
 476
 477 static void notrace ftrace_run_update_code(int command)
 478 {
 479         stop_machine_run(__ftrace_modify_code, &command, NR_CPUS);
 480 }
 481
 482 static ftrace_func_t saved_ftrace_func;
 483
 484 static void notrace ftrace_startup(void)
 485 {
 486         int command = 0;
 487
 488         mutex_lock(&ftraced_lock);
 489         ftraced_suspend++;
 490         if (ftraced_suspend == 1)
 491                 command |= FTRACE_ENABLE_CALLS;
 492
 493         if (saved_ftrace_func != ftrace_trace_function) {
 494                 saved_ftrace_func = ftrace_trace_function;
 495                 command |= FTRACE_UPDATE_TRACE_FUNC;
 496         }
 497
 498         if (!command || !ftrace_enabled)
 499                 goto out;
 500
 501         ftrace_run_update_code(command);
 502  out:
 503         mutex_unlock(&ftraced_lock);
 504 }
 505
 506 static void notrace ftrace_shutdown(void)
 507 {
 508         int command = 0;
 509
 510         mutex_lock(&ftraced_lock);
 511         ftraced_suspend--;
 512         if (!ftraced_suspend)
 513                 command |= FTRACE_DISABLE_CALLS;
 514
 515         if (saved_ftrace_func != ftrace_trace_function) {
 516                 saved_ftrace_func = ftrace_trace_function;
 517                 command |= FTRACE_UPDATE_TRACE_FUNC;
 518         }
 519
 520         if (!command || !ftrace_enabled)
 521                 goto out;
 522
 523         ftrace_run_update_code(command);
 524  out:
 525         mutex_unlock(&ftraced_lock);
 526 }
 527
 528 static void notrace ftrace_startup_sysctl(void)
 529 {
 530         int command = FTRACE_ENABLE_MCOUNT;
 531
 532         mutex_lock(&ftraced_lock);
 533         /* Force update next time */
 534         saved_ftrace_func = NULL;
 535         /* ftraced_suspend is true if we want ftrace running */
 536         if (ftraced_suspend)
 537                 command |= FTRACE_ENABLE_CALLS;
 538
 539         ftrace_run_update_code(command);
 540         mutex_unlock(&ftraced_lock);
 541 }
 542
 543 static void notrace ftrace_shutdown_sysctl(void)
 544 {
 545         int command = FTRACE_DISABLE_MCOUNT;
 546
 547         mutex_lock(&ftraced_lock);
 548         /* ftraced_suspend is true if ftrace is running */
 549         if (ftraced_suspend)
 550                 command |= FTRACE_DISABLE_CALLS;
 551
 552         ftrace_run_update_code(command);
 553         mutex_unlock(&ftraced_lock);
 554 }
 555
 556 static cycle_t          ftrace_update_time;
 557 static unsigned long    ftrace_update_cnt;
 558 unsigned long           ftrace_update_tot_cnt;
 559
 560 static int notrace __ftrace_update_code(void *ignore)
 561 {
 562         struct dyn_ftrace *p;
 563         struct hlist_head head;
 564         struct hlist_node *t;
 565         int save_ftrace_enabled;
 566         cycle_t start, stop;
 567         int i;
 568
 569         /* Don't be recording funcs now */
 570         save_ftrace_enabled = ftrace_enabled;
 571         ftrace_enabled = 0;
 572
 573         start = ftrace_now(raw_smp_processor_id());
 574         ftrace_update_cnt = 0;
 575
 576         /* No locks needed, the machine is stopped! */
 577         for (i = 0; i < FTRACE_HASHSIZE; i++) {
 578                 if (hlist_empty(&ftrace_hash[i]))
 579                         continue;
 580
 581                 head = ftrace_hash[i];
 582                 INIT_HLIST_HEAD(&ftrace_hash[i]);
 583
 584                 /* all CPUS are stopped, we are safe to modify code */
 585                 hlist_for_each_entry(p, t, &head, node) {
 586                         ftrace_code_disable(p);
 587                         ftrace_update_cnt++;
 588                 }
 589
 590         }
 591
 592         stop = ftrace_now(raw_smp_processor_id());
 593         ftrace_update_time = stop - start;
 594         ftrace_update_tot_cnt += ftrace_update_cnt;
 595
 596         ftrace_enabled = save_ftrace_enabled;
 597
 598         return 0;
 599 }
 600
 601 static void notrace ftrace_update_code(void)
 602 {
 603         stop_machine_run(__ftrace_update_code, NULL, NR_CPUS);
 604 }
 605
 606 static int notrace ftraced(void *ignore)
 607 {
 608         unsigned long usecs;
 609
 610         set_current_state(TASK_INTERRUPTIBLE);
 611
 612         while (!kthread_should_stop()) {
 613
 614                 /* check once a second */
 615                 schedule_timeout(HZ);
 616
 617                 mutex_lock(&ftrace_sysctl_lock);
 618                 mutex_lock(&ftraced_lock);
 619                 if (ftrace_enabled && ftraced_trigger && !ftraced_suspend) {
 620                         ftrace_record_suspend++;
 621                         ftrace_update_code();
 622                         usecs = nsecs_to_usecs(ftrace_update_time);
 623                         if (ftrace_update_tot_cnt > 100000) {
 624                                 ftrace_update_tot_cnt = 0;
 625                                 pr_info("hm, dftrace overflow: %lu change%s"
 626                                          " (%lu total) in %lu usec%s\n",
 627                                         ftrace_update_cnt,
 628                                         ftrace_update_cnt != 1 ? "s" : "",
 629                                         ftrace_update_tot_cnt,
 630                                         usecs, usecs != 1 ? "s" : "");
 631                                 WARN_ON_ONCE(1);
 632                         }
 633                         ftraced_trigger = 0;
 634                         ftrace_record_suspend--;
 635                 }
 636                 ftraced_iteration_counter++;
 637                 mutex_unlock(&ftraced_lock);
 638                 mutex_unlock(&ftrace_sysctl_lock);
 639
 640                 wake_up_interruptible(&ftraced_waiters);
 641
 642                 ftrace_shutdown_replenish();
 643
 644                 set_current_state(TASK_INTERRUPTIBLE);
 645         }
 646         __set_current_state(TASK_RUNNING);
 647         return 0;
 648 }
 649
 650 static int __init ftrace_dyn_table_alloc(void)
 651 {
 652         struct ftrace_page *pg;
 653         int cnt;
 654         int i;
 655
 656         /* allocate a few pages */
 657         ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
 658         if (!ftrace_pages_start)
 659                 return -1;
 660
 661         /*
 662          * Allocate a few more pages.
 663          *
 664          * TODO: have some parser search vmlinux before
 665          *   final linking to find all calls to ftrace.
 666          *   Then we can:
 667          *    a) know how many pages to allocate.
 668          *     and/or
 669          *    b) set up the table then.
 670          *
 671          *  The dynamic code is still necessary for
 672          *  modules.
 673          */
 674
 675         pg = ftrace_pages = ftrace_pages_start;
 676
 677         cnt = NR_TO_INIT / ENTRIES_PER_PAGE;
 678
 679         for (i = 0; i < cnt; i++) {
 680                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
 681
 682                 /* If we fail, we'll try later anyway */
 683                 if (!pg->next)
 684                         break;
 685
 686                 pg = pg->next;
 687         }
 688
 689         return 0;
 690 }
 691
 692 enum {
 693         FTRACE_ITER_FILTER      = (1 << 0),
 694         FTRACE_ITER_CONT        = (1 << 1),
 695 };
 696
 697 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
 698
 699 struct ftrace_iterator {
 700         loff_t                  pos;
 701         struct ftrace_page      *pg;
 702         unsigned                idx;
 703         unsigned                flags;
 704         unsigned char           buffer[FTRACE_BUFF_MAX+1];
 705         unsigned                buffer_idx;
 706         unsigned                filtered;
 707 };
 708
 709 static void notrace *
 710 t_next(struct seq_file *m, void *v, loff_t *pos)
 711 {
 712         struct ftrace_iterator *iter = m->private;
 713         struct dyn_ftrace *rec = NULL;
 714
 715         (*pos)++;
 716
 717  retry:
 718         if (iter->idx >= iter->pg->index) {
 719                 if (iter->pg->next) {
 720                         iter->pg = iter->pg->next;
 721                         iter->idx = 0;
 722                         goto retry;
 723                 }
 724         } else {
 725                 rec = &iter->pg->records[iter->idx++];
 726                 if ((rec->flags & FTRACE_FL_FAILED) ||
 727                     ((iter->flags & FTRACE_ITER_FILTER) &&
 728                      !(rec->flags & FTRACE_FL_FILTER))) {
 729                         rec = NULL;
 730                         goto retry;
 731                 }
 732         }
 733
 734         iter->pos = *pos;
 735
 736         return rec;
 737 }
 738
 739 static void *t_start(struct seq_file *m, loff_t *pos)
 740 {
 741         struct ftrace_iterator *iter = m->private;
 742         void *p = NULL;
 743         loff_t l = -1;
 744
 745         if (*pos != iter->pos) {
 746                 for (p = t_next(m, p, &l); p && l < *pos; p = t_next(m, p, &l))
 747                         ;
 748         } else {
 749                 l = *pos;
 750                 p = t_next(m, p, &l);
 751         }
 752
 753         return p;
 754 }
 755
 756 static void t_stop(struct seq_file *m, void *p)
 757 {
 758 }
 759
 760 static int t_show(struct seq_file *m, void *v)
 761 {
 762         struct dyn_ftrace *rec = v;
 763         char str[KSYM_SYMBOL_LEN];
 764
 765         if (!rec)
 766                 return 0;
 767
 768         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 769
 770         seq_printf(m, "%s\n", str);
 771
 772         return 0;
 773 }
 774
 775 static struct seq_operations show_ftrace_seq_ops = {
 776         .start = t_start,
 777         .next = t_next,
 778         .stop = t_stop,
 779         .show = t_show,
 780 };
 781
 782 static int notrace
 783 ftrace_avail_open(struct inode *inode, struct file *file)
 784 {
 785         struct ftrace_iterator *iter;
 786         int ret;
 787
 788         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
 789         if (!iter)
 790                 return -ENOMEM;
 791
 792         iter->pg = ftrace_pages_start;
 793         iter->pos = -1;
 794
 795         ret = seq_open(file, &show_ftrace_seq_ops);
 796         if (!ret) {
 797                 struct seq_file *m = file->private_data;
 798
 799                 m->private = iter;
 800         } else {
 801                 kfree(iter);
 802         }
 803
 804         return ret;
 805 }
 806
 807 int ftrace_avail_release(struct inode *inode, struct file *file)
 808 {
 809         struct seq_file *m = (struct seq_file *)file->private_data;
 810         struct ftrace_iterator *iter = m->private;
 811
 812         seq_release(inode, file);
 813         kfree(iter);
 814
 815         return 0;
 816 }
 817
 818 static void notrace ftrace_filter_reset(void)
 819 {
 820         struct ftrace_page *pg;
 821         struct dyn_ftrace *rec;
 822         unsigned i;
 823
 824         /* keep kstop machine from running */
 825         preempt_disable();
 826         ftrace_filtered = 0;
 827         pg = ftrace_pages_start;
 828         while (pg) {
 829                 for (i = 0; i < pg->index; i++) {
 830                         rec = &pg->records[i];
 831                         if (rec->flags & FTRACE_FL_FAILED)
 832                                 continue;
 833                         rec->flags &= ~FTRACE_FL_FILTER;
 834                 }
 835                 pg = pg->next;
 836         }
 837         preempt_enable();
 838 }
 839
 840 static int notrace
 841 ftrace_filter_open(struct inode *inode, struct file *file)
 842 {
 843         struct ftrace_iterator *iter;
 844         int ret = 0;
 845
 846         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
 847         if (!iter)
 848                 return -ENOMEM;
 849
 850         mutex_lock(&ftrace_filter_lock);
 851         if ((file->f_mode & FMODE_WRITE) &&
 852             !(file->f_flags & O_APPEND))
 853                 ftrace_filter_reset();
 854
 855         if (file->f_mode & FMODE_READ) {
 856                 iter->pg = ftrace_pages_start;
 857                 iter->pos = -1;
 858                 iter->flags = FTRACE_ITER_FILTER;
 859
 860                 ret = seq_open(file, &show_ftrace_seq_ops);
 861                 if (!ret) {
 862                         struct seq_file *m = file->private_data;
 863                         m->private = iter;
 864                 } else
 865                         kfree(iter);
 866         } else
 867                 file->private_data = iter;
 868         mutex_unlock(&ftrace_filter_lock);
 869
 870         return ret;
 871 }
 872
 873 static ssize_t notrace
 874 ftrace_filter_read(struct file *file, char __user *ubuf,
 875                        size_t cnt, loff_t *ppos)
 876 {
 877         if (file->f_mode & FMODE_READ)
 878                 return seq_read(file, ubuf, cnt, ppos);
 879         else
 880                 return -EPERM;
 881 }
 882
 883 static loff_t notrace
 884 ftrace_filter_lseek(struct file *file, loff_t offset, int origin)
 885 {
 886         loff_t ret;
 887
 888         if (file->f_mode & FMODE_READ)
 889                 ret = seq_lseek(file, offset, origin);
 890         else
 891                 file->f_pos = ret = 1;
 892
 893         return ret;
 894 }
 895
 896 enum {
 897         MATCH_FULL,
 898         MATCH_FRONT_ONLY,
 899         MATCH_MIDDLE_ONLY,
 900         MATCH_END_ONLY,
 901 };
 902
 903 static void notrace
 904 ftrace_match(unsigned char *buff, int len)
 905 {
 906         char str[KSYM_SYMBOL_LEN];
 907         char *search = NULL;
 908         struct ftrace_page *pg;
 909         struct dyn_ftrace *rec;
 910         int type = MATCH_FULL;
 911         unsigned i, match = 0, search_len = 0;
 912
 913         for (i = 0; i < len; i++) {
 914                 if (buff[i] == '*') {
 915                         if (!i) {
 916                                 search = buff + i + 1;
 917                                 type = MATCH_END_ONLY;
 918                                 search_len = len - (i + 1);
 919                         } else {
 920                                 if (type == MATCH_END_ONLY) {
 921                                         type = MATCH_MIDDLE_ONLY;
 922                                 } else {
 923                                         match = i;
 924                                         type = MATCH_FRONT_ONLY;
 925                                 }
 926                                 buff[i] = 0;
 927                                 break;
 928                         }
 929                 }
 930         }
 931
 932         /* keep kstop machine from running */
 933         preempt_disable();
 934         ftrace_filtered = 1;
 935         pg = ftrace_pages_start;
 936         while (pg) {
 937                 for (i = 0; i < pg->index; i++) {
 938                         int matched = 0;
 939                         char *ptr;
 940
 941                         rec = &pg->records[i];
 942                         if (rec->flags & FTRACE_FL_FAILED)
 943                                 continue;
 944                         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 945                         switch (type) {
 946                         case MATCH_FULL:
 947                                 if (strcmp(str, buff) == 0)
 948                                         matched = 1;
 949                                 break;
 950                         case MATCH_FRONT_ONLY:
 951                                 if (memcmp(str, buff, match) == 0)
 952                                         matched = 1;
 953                                 break;
 954                         case MATCH_MIDDLE_ONLY:
 955                                 if (strstr(str, search))
 956                                         matched = 1;
 957                                 break;
 958                         case MATCH_END_ONLY:
 959                                 ptr = strstr(str, search);
 960                                 if (ptr && (ptr[search_len] == 0))
 961                                         matched = 1;
 962                                 break;
 963                         }
 964                         if (matched)
 965                                 rec->flags |= FTRACE_FL_FILTER;
 966                 }
 967                 pg = pg->next;
 968         }
 969         preempt_enable();
 970 }
 971
 972 static ssize_t notrace
 973 ftrace_filter_write(struct file *file, const char __user *ubuf,
 974                     size_t cnt, loff_t *ppos)
 975 {
 976         struct ftrace_iterator *iter;
 977         char ch;
 978         size_t read = 0;
 979         ssize_t ret;
 980
 981         if (!cnt || cnt < 0)
 982                 return 0;
 983
 984         mutex_lock(&ftrace_filter_lock);
 985
 986         if (file->f_mode & FMODE_READ) {
 987                 struct seq_file *m = file->private_data;
 988                 iter = m->private;
 989         } else
 990                 iter = file->private_data;
 991
 992         if (!*ppos) {
 993                 iter->flags &= ~FTRACE_ITER_CONT;
 994                 iter->buffer_idx = 0;
 995         }
 996
 997         ret = get_user(ch, ubuf++);
 998         if (ret)
 999                 goto out;
1000         read++;
1001         cnt--;
1002
1003         if (!(iter->flags & ~FTRACE_ITER_CONT)) {
1004                 /* skip white space */
1005                 while (cnt && isspace(ch)) {
1006                         ret = get_user(ch, ubuf++);
1007                         if (ret)
1008                                 goto out;
1009                         read++;
1010                         cnt--;
1011                 }
1012
1013
1014                 if (isspace(ch)) {
1015                         file->f_pos += read;
1016                         ret = read;
1017                         goto out;
1018                 }
1019
1020                 iter->buffer_idx = 0;
1021         }
1022
1023         while (cnt && !isspace(ch)) {
1024                 if (iter->buffer_idx < FTRACE_BUFF_MAX)
1025                         iter->buffer[iter->buffer_idx++] = ch;
1026                 else {
1027                         ret = -EINVAL;
1028                         goto out;
1029                 }
1030                 ret = get_user(ch, ubuf++);
1031                 if (ret)
1032                         goto out;
1033                 read++;
1034                 cnt--;
1035         }
1036
1037         if (isspace(ch)) {
1038                 iter->filtered++;
1039                 iter->buffer[iter->buffer_idx] = 0;
1040                 ftrace_match(iter->buffer, iter->buffer_idx);
1041                 iter->buffer_idx = 0;
1042         } else
1043                 iter->flags |= FTRACE_ITER_CONT;
1044
1045
1046         file->f_pos += read;
1047
1048         ret = read;
1049  out:
1050         mutex_unlock(&ftrace_filter_lock);
1051
1052         return ret;
1053 }
1054
1055 /**
1056  * ftrace_set_filter - set a function to filter on in ftrace
1057  * @buf - the string that holds the function filter text.
1058  * @len - the length of the string.
1059  * @reset - non zero to reset all filters before applying this filter.
1060  *
1061  * Filters denote which functions should be enabled when tracing is enabled.
1062  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
1063  */
1064 notrace void ftrace_set_filter(unsigned char *buf, int len, int reset)
1065 {
1066         mutex_lock(&ftrace_filter_lock);
1067         if (reset)
1068                 ftrace_filter_reset();
1069         if (buf)
1070                 ftrace_match(buf, len);
1071         mutex_unlock(&ftrace_filter_lock);
1072 }
1073
1074 static int notrace
1075 ftrace_filter_release(struct inode *inode, struct file *file)
1076 {
1077         struct seq_file *m = (struct seq_file *)file->private_data;
1078         struct ftrace_iterator *iter;
1079
1080         mutex_lock(&ftrace_filter_lock);
1081         if (file->f_mode & FMODE_READ) {
1082                 iter = m->private;
1083
1084                 seq_release(inode, file);
1085         } else
1086                 iter = file->private_data;
1087
1088         if (iter->buffer_idx) {
1089                 iter->filtered++;
1090                 iter->buffer[iter->buffer_idx] = 0;
1091                 ftrace_match(iter->buffer, iter->buffer_idx);
1092         }
1093
1094         mutex_lock(&ftrace_sysctl_lock);
1095         mutex_lock(&ftraced_lock);
1096         if (iter->filtered && ftraced_suspend && ftrace_enabled)
1097                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
1098         mutex_unlock(&ftraced_lock);
1099         mutex_unlock(&ftrace_sysctl_lock);
1100
1101         kfree(iter);
1102         mutex_unlock(&ftrace_filter_lock);
1103         return 0;
1104 }
1105
1106 static struct file_operations ftrace_avail_fops = {
1107         .open = ftrace_avail_open,
1108         .read = seq_read,
1109         .llseek = seq_lseek,
1110         .release = ftrace_avail_release,
1111 };
1112
1113 static struct file_operations ftrace_filter_fops = {
1114         .open = ftrace_filter_open,
1115         .read = ftrace_filter_read,
1116         .write = ftrace_filter_write,
1117         .llseek = ftrace_filter_lseek,
1118         .release = ftrace_filter_release,
1119 };
1120
1121 /**
1122  * ftrace_force_update - force an update to all recording ftrace functions
1123  *
1124  * The ftrace dynamic update daemon only wakes up once a second.
1125  * There may be cases where an update needs to be done immediately
1126  * for tests or internal kernel tracing to begin. This function
1127  * wakes the daemon to do an update and will not return until the
1128  * update is complete.
1129  */
1130 int ftrace_force_update(void)
1131 {
1132         unsigned long last_counter;
1133         DECLARE_WAITQUEUE(wait, current);
1134         int ret = 0;
1135
1136         if (!ftraced_task)
1137                 return -ENODEV;
1138
1139         mutex_lock(&ftraced_lock);
1140         last_counter = ftraced_iteration_counter;
1141
1142         set_current_state(TASK_INTERRUPTIBLE);
1143         add_wait_queue(&ftraced_waiters, &wait);
1144
1145         do {
1146                 mutex_unlock(&ftraced_lock);
1147                 wake_up_process(ftraced_task);
1148                 schedule();
1149                 mutex_lock(&ftraced_lock);
1150                 if (signal_pending(current)) {
1151                         ret = -EINTR;
1152                         break;
1153                 }
1154                 set_current_state(TASK_INTERRUPTIBLE);
1155         } while (last_counter == ftraced_iteration_counter);
1156
1157         mutex_unlock(&ftraced_lock);
1158         remove_wait_queue(&ftraced_waiters, &wait);
1159         set_current_state(TASK_RUNNING);
1160
1161         return ret;
1162 }
1163
1164 static __init int ftrace_init_debugfs(void)
1165 {
1166         struct dentry *d_tracer;
1167         struct dentry *entry;
1168
1169         d_tracer = tracing_init_dentry();
1170
1171         entry = debugfs_create_file("available_filter_functions", 0444,
1172                                     d_tracer, NULL, &ftrace_avail_fops);
1173         if (!entry)
1174                 pr_warning("Could not create debugfs "
1175                            "'available_filter_functions' entry\n");
1176
1177         entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer,
1178                                     NULL, &ftrace_filter_fops);
1179         if (!entry)
1180                 pr_warning("Could not create debugfs "
1181                            "'set_ftrace_filter' entry\n");
1182         return 0;
1183 }
1184
1185 fs_initcall(ftrace_init_debugfs);
1186
1187 static int __init notrace ftrace_dynamic_init(void)
1188 {
1189         struct task_struct *p;
1190         unsigned long addr;
1191         int ret;
1192
1193         addr = (unsigned long)ftrace_record_ip;
1194         stop_machine_run(ftrace_dyn_arch_init, &addr, NR_CPUS);
1195
1196         /* ftrace_dyn_arch_init places the return code in addr */
1197         if (addr)
1198                 return addr;
1199
1200         ret = ftrace_dyn_table_alloc();
1201         if (ret)
1202                 return ret;
1203
1204         p = kthread_run(ftraced, NULL, "ftraced");
1205         if (IS_ERR(p))
1206                 return -1;
1207
1208         last_ftrace_enabled = ftrace_enabled = 1;
1209         ftraced_task = p;
1210
1211         return 0;
1212 }
1213
1214 core_initcall(ftrace_dynamic_init);
1215 #else
1216 # define ftrace_startup()               do { } while (0)
1217 # define ftrace_shutdown()              do { } while (0)
1218 # define ftrace_startup_sysctl()        do { } while (0)
1219 # define ftrace_shutdown_sysctl()       do { } while (0)
1220 #endif /* CONFIG_DYNAMIC_FTRACE */
1221
1222 /**
1223  * register_ftrace_function - register a function for profiling
1224  * @ops - ops structure that holds the function for profiling.
1225  *
1226  * Register a function to be called by all functions in the
1227  * kernel.
1228  *
1229  * Note: @ops->func and all the functions it calls must be labeled
1230  *       with "notrace", otherwise it will go into a
1231  *       recursive loop.
1232  */
1233 int register_ftrace_function(struct ftrace_ops *ops)
1234 {
1235         int ret;
1236
1237         mutex_lock(&ftrace_sysctl_lock);
1238         ret = __register_ftrace_function(ops);
1239         ftrace_startup();
1240         mutex_unlock(&ftrace_sysctl_lock);
1241
1242         return ret;
1243 }
1244
1245 /**
1246  * unregister_ftrace_function - unresgister a function for profiling.
1247  * @ops - ops structure that holds the function to unregister
1248  *
1249  * Unregister a function that was added to be called by ftrace profiling.
1250  */
1251 int unregister_ftrace_function(struct ftrace_ops *ops)
1252 {
1253         int ret;
1254
1255         mutex_lock(&ftrace_sysctl_lock);
1256         ret = __unregister_ftrace_function(ops);
1257         ftrace_shutdown();
1258         mutex_unlock(&ftrace_sysctl_lock);
1259
1260         return ret;
1261 }
1262
1263 notrace int
1264 ftrace_enable_sysctl(struct ctl_table *table, int write,
1265                      struct file *file, void __user *buffer, size_t *lenp,
1266                      loff_t *ppos)
1267 {
1268         int ret;
1269
1270         mutex_lock(&ftrace_sysctl_lock);
1271
1272         ret  = proc_dointvec(table, write, file, buffer, lenp, ppos);
1273
1274         if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
1275                 goto out;
1276
1277         last_ftrace_enabled = ftrace_enabled;
1278
1279         if (ftrace_enabled) {
1280
1281                 ftrace_startup_sysctl();
1282
1283                 /* we are starting ftrace again */
1284                 if (ftrace_list != &ftrace_list_end) {
1285                         if (ftrace_list->next == &ftrace_list_end)
1286                                 ftrace_trace_function = ftrace_list->func;
1287                         else
1288                                 ftrace_trace_function = ftrace_list_func;
1289                 }
1290
1291         } else {
1292                 /* stopping ftrace calls (just send to ftrace_stub) */
1293                 ftrace_trace_function = ftrace_stub;
1294
1295                 ftrace_shutdown_sysctl();
1296         }
1297
1298  out:
1299         mutex_unlock(&ftrace_sysctl_lock);
1300         return ret;
1301 }