SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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 inline int
 192 notrace ftrace_ip_in_hash(unsigned long ip, unsigned long key)
 193 {
 194         struct dyn_ftrace *p;
 195         struct hlist_node *t;
 196         int found = 0;
 197
 198         hlist_for_each_entry(p, t, &ftrace_hash[key], node) {
 199                 if (p->ip == ip) {
 200                         found = 1;
 201                         break;
 202                 }
 203         }
 204
 205         return found;
 206 }
 207
 208 static inline void notrace
 209 ftrace_add_hash(struct dyn_ftrace *node, unsigned long key)
 210 {
 211         hlist_add_head(&node->node, &ftrace_hash[key]);
 212 }
 213
 214 static notrace struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
 215 {
 216         if (ftrace_pages->index == ENTRIES_PER_PAGE) {
 217                 if (!ftrace_pages->next)
 218                         return NULL;
 219                 ftrace_pages = ftrace_pages->next;
 220         }
 221
 222         return &ftrace_pages->records[ftrace_pages->index++];
 223 }
 224
 225 static void notrace
 226 ftrace_record_ip(unsigned long ip)
 227 {
 228         struct dyn_ftrace *node;
 229         unsigned long flags;
 230         unsigned long key;
 231         int resched;
 232         int atomic;
 233
 234         if (!ftrace_enabled)
 235                 return;
 236
 237         resched = need_resched();
 238         preempt_disable_notrace();
 239
 240         /* We simply need to protect against recursion */
 241         __get_cpu_var(ftrace_shutdown_disable_cpu)++;
 242         if (__get_cpu_var(ftrace_shutdown_disable_cpu) != 1)
 243                 goto out;
 244
 245         if (unlikely(ftrace_record_suspend))
 246                 goto out;
 247
 248         key = hash_long(ip, FTRACE_HASHBITS);
 249
 250         WARN_ON_ONCE(key >= FTRACE_HASHSIZE);
 251
 252         if (ftrace_ip_in_hash(ip, key))
 253                 goto out;
 254
 255         atomic = irqs_disabled();
 256
 257         spin_lock_irqsave(&ftrace_shutdown_lock, flags);
 258
 259         /* This ip may have hit the hash before the lock */
 260         if (ftrace_ip_in_hash(ip, key))
 261                 goto out_unlock;
 262
 263         /*
 264          * There's a slight race that the ftraced will update the
 265          * hash and reset here. If it is already converted, skip it.
 266          */
 267         if (ftrace_ip_converted(ip))
 268                 goto out_unlock;
 269
 270         node = ftrace_alloc_dyn_node(ip);
 271         if (!node)
 272                 goto out_unlock;
 273
 274         node->ip = ip;
 275
 276         ftrace_add_hash(node, key);
 277
 278         ftraced_trigger = 1;
 279
 280  out_unlock:
 281         spin_unlock_irqrestore(&ftrace_shutdown_lock, flags);
 282  out:
 283         __get_cpu_var(ftrace_shutdown_disable_cpu)--;
 284
 285         /* prevent recursion with scheduler */
 286         if (resched)
 287                 preempt_enable_no_resched_notrace();
 288         else
 289                 preempt_enable_notrace();
 290 }
 291
 292 #define FTRACE_ADDR ((long)(&ftrace_caller))
 293 #define MCOUNT_ADDR ((long)(&mcount))
 294
 295 static void notrace
 296 __ftrace_replace_code(struct dyn_ftrace *rec,
 297                       unsigned char *old, unsigned char *new, int enable)
 298 {
 299         unsigned long ip;
 300         int failed;
 301
 302         ip = rec->ip;
 303
 304         if (ftrace_filtered && enable) {
 305                 unsigned long fl;
 306                 /*
 307                  * If filtering is on:
 308                  *
 309                  * If this record is set to be filtered and
 310                  * is enabled then do nothing.
 311                  *
 312                  * If this record is set to be filtered and
 313                  * it is not enabled, enable it.
 314                  *
 315                  * If this record is not set to be filtered
 316                  * and it is not enabled do nothing.
 317                  *
 318                  * If this record is not set to be filtered and
 319                  * it is enabled, disable it.
 320                  */
 321                 fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED);
 322
 323                 if ((fl ==  (FTRACE_FL_FILTER | FTRACE_FL_ENABLED)) ||
 324                     (fl == 0))
 325                         return;
 326
 327                 /*
 328                  * If it is enabled disable it,
 329                  * otherwise enable it!
 330                  */
 331                 if (fl == FTRACE_FL_ENABLED) {
 332                         /* swap new and old */
 333                         new = old;
 334                         old = ftrace_call_replace(ip, FTRACE_ADDR);
 335                         rec->flags &= ~FTRACE_FL_ENABLED;
 336                 } else {
 337                         new = ftrace_call_replace(ip, FTRACE_ADDR);
 338                         rec->flags |= FTRACE_FL_ENABLED;
 339                 }
 340         } else {
 341
 342                 if (enable)
 343                         new = ftrace_call_replace(ip, FTRACE_ADDR);
 344                 else
 345                         old = ftrace_call_replace(ip, FTRACE_ADDR);
 346
 347                 if (enable) {
 348                         if (rec->flags & FTRACE_FL_ENABLED)
 349                                 return;
 350                         rec->flags |= FTRACE_FL_ENABLED;
 351                 } else {
 352                         if (!(rec->flags & FTRACE_FL_ENABLED))
 353                                 return;
 354                         rec->flags &= ~FTRACE_FL_ENABLED;
 355                 }
 356         }
 357
 358         failed = ftrace_modify_code(ip, old, new);
 359         if (failed)
 360                 rec->flags |= FTRACE_FL_FAILED;
 361 }
 362
 363 static void notrace ftrace_replace_code(int enable)
 364 {
 365         unsigned char *new = NULL, *old = NULL;
 366         struct dyn_ftrace *rec;
 367         struct ftrace_page *pg;
 368         int i;
 369
 370         if (enable)
 371                 old = ftrace_nop_replace();
 372         else
 373                 new = ftrace_nop_replace();
 374
 375         for (pg = ftrace_pages_start; pg; pg = pg->next) {
 376                 for (i = 0; i < pg->index; i++) {
 377                         rec = &pg->records[i];
 378
 379                         /* don't modify code that has already faulted */
 380                         if (rec->flags & FTRACE_FL_FAILED)
 381                                 continue;
 382
 383                         __ftrace_replace_code(rec, old, new, enable);
 384                 }
 385         }
 386 }
 387
 388 static notrace void ftrace_shutdown_replenish(void)
 389 {
 390         if (ftrace_pages->next)
 391                 return;
 392
 393         /* allocate another page */
 394         ftrace_pages->next = (void *)get_zeroed_page(GFP_KERNEL);
 395 }
 396
 397 static notrace void
 398 ftrace_code_disable(struct dyn_ftrace *rec)
 399 {
 400         unsigned long ip;
 401         unsigned char *nop, *call;
 402         int failed;
 403
 404         ip = rec->ip;
 405
 406         nop = ftrace_nop_replace();
 407         call = ftrace_call_replace(ip, MCOUNT_ADDR);
 408
 409         failed = ftrace_modify_code(ip, call, nop);
 410         if (failed)
 411                 rec->flags |= FTRACE_FL_FAILED;
 412 }
 413
 414 static int notrace __ftrace_modify_code(void *data)
 415 {
 416         unsigned long addr;
 417         int *command = data;
 418
 419         if (*command & FTRACE_ENABLE_CALLS)
 420                 ftrace_replace_code(1);
 421         else if (*command & FTRACE_DISABLE_CALLS)
 422                 ftrace_replace_code(0);
 423
 424         if (*command & FTRACE_UPDATE_TRACE_FUNC)
 425                 ftrace_update_ftrace_func(ftrace_trace_function);
 426
 427         if (*command & FTRACE_ENABLE_MCOUNT) {
 428                 addr = (unsigned long)ftrace_record_ip;
 429                 ftrace_mcount_set(&addr);
 430         } else if (*command & FTRACE_DISABLE_MCOUNT) {
 431                 addr = (unsigned long)ftrace_stub;
 432                 ftrace_mcount_set(&addr);
 433         }
 434
 435         return 0;
 436 }
 437
 438 static void notrace ftrace_run_update_code(int command)
 439 {
 440         stop_machine_run(__ftrace_modify_code, &command, NR_CPUS);
 441 }
 442
 443 static ftrace_func_t saved_ftrace_func;
 444
 445 static void notrace ftrace_startup(void)
 446 {
 447         int command = 0;
 448
 449         mutex_lock(&ftraced_lock);
 450         ftraced_suspend++;
 451         if (ftraced_suspend == 1)
 452                 command |= FTRACE_ENABLE_CALLS;
 453
 454         if (saved_ftrace_func != ftrace_trace_function) {
 455                 saved_ftrace_func = ftrace_trace_function;
 456                 command |= FTRACE_UPDATE_TRACE_FUNC;
 457         }
 458
 459         if (!command || !ftrace_enabled)
 460                 goto out;
 461
 462         ftrace_run_update_code(command);
 463  out:
 464         mutex_unlock(&ftraced_lock);
 465 }
 466
 467 static void notrace ftrace_shutdown(void)
 468 {
 469         int command = 0;
 470
 471         mutex_lock(&ftraced_lock);
 472         ftraced_suspend--;
 473         if (!ftraced_suspend)
 474                 command |= FTRACE_DISABLE_CALLS;
 475
 476         if (saved_ftrace_func != ftrace_trace_function) {
 477                 saved_ftrace_func = ftrace_trace_function;
 478                 command |= FTRACE_UPDATE_TRACE_FUNC;
 479         }
 480
 481         if (!command || !ftrace_enabled)
 482                 goto out;
 483
 484         ftrace_run_update_code(command);
 485  out:
 486         mutex_unlock(&ftraced_lock);
 487 }
 488
 489 static void notrace ftrace_startup_sysctl(void)
 490 {
 491         int command = FTRACE_ENABLE_MCOUNT;
 492
 493         mutex_lock(&ftraced_lock);
 494         /* Force update next time */
 495         saved_ftrace_func = NULL;
 496         /* ftraced_suspend is true if we want ftrace running */
 497         if (ftraced_suspend)
 498                 command |= FTRACE_ENABLE_CALLS;
 499
 500         ftrace_run_update_code(command);
 501         mutex_unlock(&ftraced_lock);
 502 }
 503
 504 static void notrace ftrace_shutdown_sysctl(void)
 505 {
 506         int command = FTRACE_DISABLE_MCOUNT;
 507
 508         mutex_lock(&ftraced_lock);
 509         /* ftraced_suspend is true if ftrace is running */
 510         if (ftraced_suspend)
 511                 command |= FTRACE_DISABLE_CALLS;
 512
 513         ftrace_run_update_code(command);
 514         mutex_unlock(&ftraced_lock);
 515 }
 516
 517 static cycle_t          ftrace_update_time;
 518 static unsigned long    ftrace_update_cnt;
 519 unsigned long           ftrace_update_tot_cnt;
 520
 521 static int notrace __ftrace_update_code(void *ignore)
 522 {
 523         struct dyn_ftrace *p;
 524         struct hlist_head head;
 525         struct hlist_node *t;
 526         int save_ftrace_enabled;
 527         cycle_t start, stop;
 528         int i;
 529
 530         /* Don't be recording funcs now */
 531         save_ftrace_enabled = ftrace_enabled;
 532         ftrace_enabled = 0;
 533
 534         start = now(raw_smp_processor_id());
 535         ftrace_update_cnt = 0;
 536
 537         /* No locks needed, the machine is stopped! */
 538         for (i = 0; i < FTRACE_HASHSIZE; i++) {
 539                 if (hlist_empty(&ftrace_hash[i]))
 540                         continue;
 541
 542                 head = ftrace_hash[i];
 543                 INIT_HLIST_HEAD(&ftrace_hash[i]);
 544
 545                 /* all CPUS are stopped, we are safe to modify code */
 546                 hlist_for_each_entry(p, t, &head, node) {
 547                         ftrace_code_disable(p);
 548                         ftrace_update_cnt++;
 549                 }
 550
 551         }
 552
 553         stop = now(raw_smp_processor_id());
 554         ftrace_update_time = stop - start;
 555         ftrace_update_tot_cnt += ftrace_update_cnt;
 556
 557         ftrace_enabled = save_ftrace_enabled;
 558
 559         return 0;
 560 }
 561
 562 static void notrace ftrace_update_code(void)
 563 {
 564         stop_machine_run(__ftrace_update_code, NULL, NR_CPUS);
 565 }
 566
 567 static int notrace ftraced(void *ignore)
 568 {
 569         unsigned long usecs;
 570
 571         set_current_state(TASK_INTERRUPTIBLE);
 572
 573         while (!kthread_should_stop()) {
 574
 575                 /* check once a second */
 576                 schedule_timeout(HZ);
 577
 578                 mutex_lock(&ftrace_sysctl_lock);
 579                 mutex_lock(&ftraced_lock);
 580                 if (ftrace_enabled && ftraced_trigger && !ftraced_suspend) {
 581                         ftrace_record_suspend++;
 582                         ftrace_update_code();
 583                         usecs = nsecs_to_usecs(ftrace_update_time);
 584                         if (ftrace_update_tot_cnt > 100000) {
 585                                 ftrace_update_tot_cnt = 0;
 586                                 pr_info("hm, dftrace overflow: %lu change%s"
 587                                          " (%lu total) in %lu usec%s\n",
 588                                         ftrace_update_cnt,
 589                                         ftrace_update_cnt != 1 ? "s" : "",
 590                                         ftrace_update_tot_cnt,
 591                                         usecs, usecs != 1 ? "s" : "");
 592                                 WARN_ON_ONCE(1);
 593                         }
 594                         ftraced_trigger = 0;
 595                         ftrace_record_suspend--;
 596                 }
 597                 ftraced_iteration_counter++;
 598                 mutex_unlock(&ftraced_lock);
 599                 mutex_unlock(&ftrace_sysctl_lock);
 600
 601                 wake_up_interruptible(&ftraced_waiters);
 602
 603                 ftrace_shutdown_replenish();
 604
 605                 set_current_state(TASK_INTERRUPTIBLE);
 606         }
 607         __set_current_state(TASK_RUNNING);
 608         return 0;
 609 }
 610
 611 static int __init ftrace_dyn_table_alloc(void)
 612 {
 613         struct ftrace_page *pg;
 614         int cnt;
 615         int i;
 616
 617         /* allocate a few pages */
 618         ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
 619         if (!ftrace_pages_start)
 620                 return -1;
 621
 622         /*
 623          * Allocate a few more pages.
 624          *
 625          * TODO: have some parser search vmlinux before
 626          *   final linking to find all calls to ftrace.
 627          *   Then we can:
 628          *    a) know how many pages to allocate.
 629          *     and/or
 630          *    b) set up the table then.
 631          *
 632          *  The dynamic code is still necessary for
 633          *  modules.
 634          */
 635
 636         pg = ftrace_pages = ftrace_pages_start;
 637
 638         cnt = NR_TO_INIT / ENTRIES_PER_PAGE;
 639
 640         for (i = 0; i < cnt; i++) {
 641                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
 642
 643                 /* If we fail, we'll try later anyway */
 644                 if (!pg->next)
 645                         break;
 646
 647                 pg = pg->next;
 648         }
 649
 650         return 0;
 651 }
 652
 653 enum {
 654         FTRACE_ITER_FILTER      = (1 << 0),
 655         FTRACE_ITER_CONT        = (1 << 1),
 656 };
 657
 658 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
 659
 660 struct ftrace_iterator {
 661         loff_t                  pos;
 662         struct ftrace_page      *pg;
 663         unsigned                idx;
 664         unsigned                flags;
 665         unsigned char           buffer[FTRACE_BUFF_MAX+1];
 666         unsigned                buffer_idx;
 667         unsigned                filtered;
 668 };
 669
 670 static void notrace *
 671 t_next(struct seq_file *m, void *v, loff_t *pos)
 672 {
 673         struct ftrace_iterator *iter = m->private;
 674         struct dyn_ftrace *rec = NULL;
 675
 676         (*pos)++;
 677
 678  retry:
 679         if (iter->idx >= iter->pg->index) {
 680                 if (iter->pg->next) {
 681                         iter->pg = iter->pg->next;
 682                         iter->idx = 0;
 683                         goto retry;
 684                 }
 685         } else {
 686                 rec = &iter->pg->records[iter->idx++];
 687                 if ((rec->flags & FTRACE_FL_FAILED) ||
 688                     ((iter->flags & FTRACE_ITER_FILTER) &&
 689                      !(rec->flags & FTRACE_FL_FILTER))) {
 690                         rec = NULL;
 691                         goto retry;
 692                 }
 693         }
 694
 695         iter->pos = *pos;
 696
 697         return rec;
 698 }
 699
 700 static void *t_start(struct seq_file *m, loff_t *pos)
 701 {
 702         struct ftrace_iterator *iter = m->private;
 703         void *p = NULL;
 704         loff_t l = -1;
 705
 706         if (*pos != iter->pos) {
 707                 for (p = t_next(m, p, &l); p && l < *pos; p = t_next(m, p, &l))
 708                         ;
 709         } else {
 710                 l = *pos;
 711                 p = t_next(m, p, &l);
 712         }
 713
 714         return p;
 715 }
 716
 717 static void t_stop(struct seq_file *m, void *p)
 718 {
 719 }
 720
 721 static int t_show(struct seq_file *m, void *v)
 722 {
 723         struct dyn_ftrace *rec = v;
 724         char str[KSYM_SYMBOL_LEN];
 725
 726         if (!rec)
 727                 return 0;
 728
 729         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 730
 731         seq_printf(m, "%s\n", str);
 732
 733         return 0;
 734 }
 735
 736 static struct seq_operations show_ftrace_seq_ops = {
 737         .start = t_start,
 738         .next = t_next,
 739         .stop = t_stop,
 740         .show = t_show,
 741 };
 742
 743 static int notrace
 744 ftrace_avail_open(struct inode *inode, struct file *file)
 745 {
 746         struct ftrace_iterator *iter;
 747         int ret;
 748
 749         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
 750         if (!iter)
 751                 return -ENOMEM;
 752
 753         iter->pg = ftrace_pages_start;
 754         iter->pos = -1;
 755
 756         ret = seq_open(file, &show_ftrace_seq_ops);
 757         if (!ret) {
 758                 struct seq_file *m = file->private_data;
 759                 m->private = iter;
 760         } else
 761                 kfree(iter);
 762
 763         return ret;
 764 }
 765
 766 int ftrace_avail_release(struct inode *inode, struct file *file)
 767 {
 768         struct seq_file *m = (struct seq_file *)file->private_data;
 769         struct ftrace_iterator *iter = m->private;
 770
 771         seq_release(inode, file);
 772         kfree(iter);
 773         return 0;
 774 }
 775
 776 static void notrace ftrace_filter_reset(void)
 777 {
 778         struct ftrace_page *pg;
 779         struct dyn_ftrace *rec;
 780         unsigned i;
 781
 782         /* keep kstop machine from running */
 783         preempt_disable();
 784         ftrace_filtered = 0;
 785         pg = ftrace_pages_start;
 786         while (pg) {
 787                 for (i = 0; i < pg->index; i++) {
 788                         rec = &pg->records[i];
 789                         if (rec->flags & FTRACE_FL_FAILED)
 790                                 continue;
 791                         rec->flags &= ~FTRACE_FL_FILTER;
 792                 }
 793                 pg = pg->next;
 794         }
 795         preempt_enable();
 796 }
 797
 798 static int notrace
 799 ftrace_filter_open(struct inode *inode, struct file *file)
 800 {
 801         struct ftrace_iterator *iter;
 802         int ret = 0;
 803
 804         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
 805         if (!iter)
 806                 return -ENOMEM;
 807
 808         mutex_lock(&ftrace_filter_lock);
 809         if ((file->f_mode & FMODE_WRITE) &&
 810             !(file->f_flags & O_APPEND))
 811                 ftrace_filter_reset();
 812
 813         if (file->f_mode & FMODE_READ) {
 814                 iter->pg = ftrace_pages_start;
 815                 iter->pos = -1;
 816                 iter->flags = FTRACE_ITER_FILTER;
 817
 818                 ret = seq_open(file, &show_ftrace_seq_ops);
 819                 if (!ret) {
 820                         struct seq_file *m = file->private_data;
 821                         m->private = iter;
 822                 } else
 823                         kfree(iter);
 824         } else
 825                 file->private_data = iter;
 826         mutex_unlock(&ftrace_filter_lock);
 827
 828         return ret;
 829 }
 830
 831 static ssize_t notrace
 832 ftrace_filter_read(struct file *file, char __user *ubuf,
 833                        size_t cnt, loff_t *ppos)
 834 {
 835         if (file->f_mode & FMODE_READ)
 836                 return seq_read(file, ubuf, cnt, ppos);
 837         else
 838                 return -EPERM;
 839 }
 840
 841 static loff_t notrace
 842 ftrace_filter_lseek(struct file *file, loff_t offset, int origin)
 843 {
 844         loff_t ret;
 845
 846         if (file->f_mode & FMODE_READ)
 847                 ret = seq_lseek(file, offset, origin);
 848         else
 849                 file->f_pos = ret = 1;
 850
 851         return ret;
 852 }
 853
 854 enum {
 855         MATCH_FULL,
 856         MATCH_FRONT_ONLY,
 857         MATCH_MIDDLE_ONLY,
 858         MATCH_END_ONLY,
 859 };
 860
 861 static void notrace
 862 ftrace_match(unsigned char *buff, int len)
 863 {
 864         char str[KSYM_SYMBOL_LEN];
 865         char *search = NULL;
 866         struct ftrace_page *pg;
 867         struct dyn_ftrace *rec;
 868         int type = MATCH_FULL;
 869         unsigned i, match = 0, search_len = 0;
 870
 871         for (i = 0; i < len; i++) {
 872                 if (buff[i] == '*') {
 873                         if (!i) {
 874                                 search = buff + i + 1;
 875                                 type = MATCH_END_ONLY;
 876                                 search_len = len - (i + 1);
 877                         } else {
 878                                 if (type == MATCH_END_ONLY) {
 879                                         type = MATCH_MIDDLE_ONLY;
 880                                 } else {
 881                                         match = i;
 882                                         type = MATCH_FRONT_ONLY;
 883                                 }
 884                                 buff[i] = 0;
 885                                 break;
 886                         }
 887                 }
 888         }
 889
 890         /* keep kstop machine from running */
 891         preempt_disable();
 892         ftrace_filtered = 1;
 893         pg = ftrace_pages_start;
 894         while (pg) {
 895                 for (i = 0; i < pg->index; i++) {
 896                         int matched = 0;
 897                         char *ptr;
 898
 899                         rec = &pg->records[i];
 900                         if (rec->flags & FTRACE_FL_FAILED)
 901                                 continue;
 902                         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 903                         switch (type) {
 904                         case MATCH_FULL:
 905                                 if (strcmp(str, buff) == 0)
 906                                         matched = 1;
 907                                 break;
 908                         case MATCH_FRONT_ONLY:
 909                                 if (memcmp(str, buff, match) == 0)
 910                                         matched = 1;
 911                                 break;
 912                         case MATCH_MIDDLE_ONLY:
 913                                 if (strstr(str, search))
 914                                         matched = 1;
 915                                 break;
 916                         case MATCH_END_ONLY:
 917                                 ptr = strstr(str, search);
 918                                 if (ptr && (ptr[search_len] == 0))
 919                                         matched = 1;
 920                                 break;
 921                         }
 922                         if (matched)
 923                                 rec->flags |= FTRACE_FL_FILTER;
 924                 }
 925                 pg = pg->next;
 926         }
 927         preempt_enable();
 928 }
 929
 930 static ssize_t notrace
 931 ftrace_filter_write(struct file *file, const char __user *ubuf,
 932                     size_t cnt, loff_t *ppos)
 933 {
 934         struct ftrace_iterator *iter;
 935         char ch;
 936         size_t read = 0;
 937         ssize_t ret;
 938
 939         if (!cnt || cnt < 0)
 940                 return 0;
 941
 942         mutex_lock(&ftrace_filter_lock);
 943
 944         if (file->f_mode & FMODE_READ) {
 945                 struct seq_file *m = file->private_data;
 946                 iter = m->private;
 947         } else
 948                 iter = file->private_data;
 949
 950         if (!*ppos) {
 951                 iter->flags &= ~FTRACE_ITER_CONT;
 952                 iter->buffer_idx = 0;
 953         }
 954
 955         ret = get_user(ch, ubuf++);
 956         if (ret)
 957                 goto out;
 958         read++;
 959         cnt--;
 960
 961         if (!(iter->flags & ~FTRACE_ITER_CONT)) {
 962                 /* skip white space */
 963                 while (cnt && isspace(ch)) {
 964                         ret = get_user(ch, ubuf++);
 965                         if (ret)
 966                                 goto out;
 967                         read++;
 968                         cnt--;
 969                 }
 970
 971
 972                 if (isspace(ch)) {
 973                         file->f_pos += read;
 974                         ret = read;
 975                         goto out;
 976                 }
 977
 978                 iter->buffer_idx = 0;
 979         }
 980
 981         while (cnt && !isspace(ch)) {
 982                 if (iter->buffer_idx < FTRACE_BUFF_MAX)
 983                         iter->buffer[iter->buffer_idx++] = ch;
 984                 else {
 985                         ret = -EINVAL;
 986                         goto out;
 987                 }
 988                 ret = get_user(ch, ubuf++);
 989                 if (ret)
 990                         goto out;
 991                 read++;
 992                 cnt--;
 993         }
 994
 995         if (isspace(ch)) {
 996                 iter->filtered++;
 997                 iter->buffer[iter->buffer_idx] = 0;
 998                 ftrace_match(iter->buffer, iter->buffer_idx);
 999                 iter->buffer_idx = 0;
1000         } else
1001                 iter->flags |= FTRACE_ITER_CONT;
1002
1003
1004         file->f_pos += read;
1005
1006         ret = read;
1007  out:
1008         mutex_unlock(&ftrace_filter_lock);
1009
1010         return ret;
1011 }
1012
1013 static int notrace
1014 ftrace_filter_release(struct inode *inode, struct file *file)
1015 {
1016         struct seq_file *m = (struct seq_file *)file->private_data;
1017         struct ftrace_iterator *iter;
1018
1019         mutex_lock(&ftrace_filter_lock);
1020         if (file->f_mode & FMODE_READ) {
1021                 iter = m->private;
1022
1023                 seq_release(inode, file);
1024         } else
1025                 iter = file->private_data;
1026
1027         if (iter->buffer_idx) {
1028                 iter->filtered++;
1029                 iter->buffer[iter->buffer_idx] = 0;
1030                 ftrace_match(iter->buffer, iter->buffer_idx);
1031         }
1032
1033         mutex_lock(&ftrace_sysctl_lock);
1034         mutex_lock(&ftraced_lock);
1035         if (iter->filtered && ftraced_suspend && ftrace_enabled)
1036                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
1037         mutex_unlock(&ftraced_lock);
1038         mutex_unlock(&ftrace_sysctl_lock);
1039
1040         kfree(iter);
1041         mutex_unlock(&ftrace_filter_lock);
1042         return 0;
1043 }
1044
1045 static struct file_operations ftrace_avail_fops = {
1046         .open = ftrace_avail_open,
1047         .read = seq_read,
1048         .llseek = seq_lseek,
1049         .release = ftrace_avail_release,
1050 };
1051
1052 static struct file_operations ftrace_filter_fops = {
1053         .open = ftrace_filter_open,
1054         .read = ftrace_filter_read,
1055         .write = ftrace_filter_write,
1056         .llseek = ftrace_filter_lseek,
1057         .release = ftrace_filter_release,
1058 };
1059
1060 /**
1061  * ftrace_force_update - force an update to all recording ftrace functions
1062  *
1063  * The ftrace dynamic update daemon only wakes up once a second.
1064  * There may be cases where an update needs to be done immediately
1065  * for tests or internal kernel tracing to begin. This function
1066  * wakes the daemon to do an update and will not return until the
1067  * update is complete.
1068  */
1069 int ftrace_force_update(void)
1070 {
1071         unsigned long last_counter;
1072         DECLARE_WAITQUEUE(wait, current);
1073         int ret = 0;
1074
1075         if (!ftraced_task)
1076                 return -ENODEV;
1077
1078         mutex_lock(&ftraced_lock);
1079         last_counter = ftraced_iteration_counter;
1080
1081         set_current_state(TASK_INTERRUPTIBLE);
1082         add_wait_queue(&ftraced_waiters, &wait);
1083
1084         do {
1085                 mutex_unlock(&ftraced_lock);
1086                 wake_up_process(ftraced_task);
1087                 schedule();
1088                 mutex_lock(&ftraced_lock);
1089                 if (signal_pending(current)) {
1090                         ret = -EINTR;
1091                         break;
1092                 }
1093                 set_current_state(TASK_INTERRUPTIBLE);
1094         } while (last_counter == ftraced_iteration_counter);
1095
1096         mutex_unlock(&ftraced_lock);
1097         remove_wait_queue(&ftraced_waiters, &wait);
1098         set_current_state(TASK_RUNNING);
1099
1100         return ret;
1101 }
1102
1103 static __init int ftrace_init_debugfs(void)
1104 {
1105         struct dentry *d_tracer;
1106         struct dentry *entry;
1107
1108         d_tracer = tracing_init_dentry();
1109
1110         entry = debugfs_create_file("available_filter_functions", 0444,
1111                                     d_tracer, NULL, &ftrace_avail_fops);
1112         if (!entry)
1113                 pr_warning("Could not create debugfs "
1114                            "'available_filter_functions' entry\n");
1115
1116         entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer,
1117                                     NULL, &ftrace_filter_fops);
1118         if (!entry)
1119                 pr_warning("Could not create debugfs "
1120                            "'set_ftrace_filter' entry\n");
1121         return 0;
1122 }
1123
1124 fs_initcall(ftrace_init_debugfs);
1125
1126 static int __init notrace ftrace_dynamic_init(void)
1127 {
1128         struct task_struct *p;
1129         unsigned long addr;
1130         int ret;
1131
1132         addr = (unsigned long)ftrace_record_ip;
1133         stop_machine_run(ftrace_dyn_arch_init, &addr, NR_CPUS);
1134
1135         /* ftrace_dyn_arch_init places the return code in addr */
1136         if (addr)
1137                 return addr;
1138
1139         ret = ftrace_dyn_table_alloc();
1140         if (ret)
1141                 return ret;
1142
1143         p = kthread_run(ftraced, NULL, "ftraced");
1144         if (IS_ERR(p))
1145                 return -1;
1146
1147         last_ftrace_enabled = ftrace_enabled = 1;
1148         ftraced_task = p;
1149
1150         return 0;
1151 }
1152
1153 core_initcall(ftrace_dynamic_init);
1154 #else
1155 # define ftrace_startup()               do { } while (0)
1156 # define ftrace_shutdown()              do { } while (0)
1157 # define ftrace_startup_sysctl()        do { } while (0)
1158 # define ftrace_shutdown_sysctl()       do { } while (0)
1159 #endif /* CONFIG_DYNAMIC_FTRACE */
1160
1161 /**
1162  * register_ftrace_function - register a function for profiling
1163  * @ops - ops structure that holds the function for profiling.
1164  *
1165  * Register a function to be called by all functions in the
1166  * kernel.
1167  *
1168  * Note: @ops->func and all the functions it calls must be labeled
1169  *       with "notrace", otherwise it will go into a
1170  *       recursive loop.
1171  */
1172 int register_ftrace_function(struct ftrace_ops *ops)
1173 {
1174         int ret;
1175
1176         mutex_lock(&ftrace_sysctl_lock);
1177         ret = __register_ftrace_function(ops);
1178         ftrace_startup();
1179         mutex_unlock(&ftrace_sysctl_lock);
1180
1181         return ret;
1182 }
1183
1184 /**
1185  * unregister_ftrace_function - unresgister a function for profiling.
1186  * @ops - ops structure that holds the function to unregister
1187  *
1188  * Unregister a function that was added to be called by ftrace profiling.
1189  */
1190 int unregister_ftrace_function(struct ftrace_ops *ops)
1191 {
1192         int ret;
1193
1194         mutex_lock(&ftrace_sysctl_lock);
1195         ret = __unregister_ftrace_function(ops);
1196         ftrace_shutdown();
1197         mutex_unlock(&ftrace_sysctl_lock);
1198
1199         return ret;
1200 }
1201
1202 notrace int
1203 ftrace_enable_sysctl(struct ctl_table *table, int write,
1204                      struct file *file, void __user *buffer, size_t *lenp,
1205                      loff_t *ppos)
1206 {
1207         int ret;
1208
1209         mutex_lock(&ftrace_sysctl_lock);
1210
1211         ret  = proc_dointvec(table, write, file, buffer, lenp, ppos);
1212
1213         if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
1214                 goto out;
1215
1216         last_ftrace_enabled = ftrace_enabled;
1217
1218         if (ftrace_enabled) {
1219
1220                 ftrace_startup_sysctl();
1221
1222                 /* we are starting ftrace again */
1223                 if (ftrace_list != &ftrace_list_end) {
1224                         if (ftrace_list->next == &ftrace_list_end)
1225                                 ftrace_trace_function = ftrace_list->func;
1226                         else
1227                                 ftrace_trace_function = ftrace_list_func;
1228                 }
1229
1230         } else {
1231                 /* stopping ftrace calls (just send to ftrace_stub) */
1232                 ftrace_trace_function = ftrace_stub;
1233
1234                 ftrace_shutdown_sysctl();
1235         }
1236
1237  out:
1238         mutex_unlock(&ftrace_sysctl_lock);
1239         return ret;
1240 }