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/hardirq.h>
  22 #include <linux/kthread.h>
  23 #include <linux/uaccess.h>
  24 #include <linux/kprobes.h>
  25 #include <linux/ftrace.h>
  26 #include <linux/sysctl.h>
  27 #include <linux/ctype.h>
  28 #include <linux/list.h>
  29
  30 #include <asm/ftrace.h>
  31
  32 #include "trace.h"
  33
  34 #define FTRACE_WARN_ON(cond)                    \
  35         do {                                    \
  36                 if (WARN_ON(cond))              \
  37                         ftrace_kill();          \
  38         } while (0)
  39
  40 #define FTRACE_WARN_ON_ONCE(cond)               \
  41         do {                                    \
  42                 if (WARN_ON_ONCE(cond))         \
  43                         ftrace_kill();          \
  44         } while (0)
  45
  46 /* ftrace_enabled is a method to turn ftrace on or off */
  47 int ftrace_enabled __read_mostly;
  48 static int last_ftrace_enabled;
  49
  50 /* Quick disabling of function tracer. */
  51 int function_trace_stop;
  52
  53 /*
  54  * ftrace_disabled is set when an anomaly is discovered.
  55  * ftrace_disabled is much stronger than ftrace_enabled.
  56  */
  57 static int ftrace_disabled __read_mostly;
  58
  59 static DEFINE_SPINLOCK(ftrace_lock);
  60 static DEFINE_MUTEX(ftrace_sysctl_lock);
  61
  62 static struct ftrace_ops ftrace_list_end __read_mostly =
  63 {
  64         .func = ftrace_stub,
  65 };
  66
  67 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
  68 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
  69 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
  70
  71 static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
  72 {
  73         struct ftrace_ops *op = ftrace_list;
  74
  75         /* in case someone actually ports this to alpha! */
  76         read_barrier_depends();
  77
  78         while (op != &ftrace_list_end) {
  79                 /* silly alpha */
  80                 read_barrier_depends();
  81                 op->func(ip, parent_ip);
  82                 op = op->next;
  83         };
  84 }
  85
  86 /**
  87  * clear_ftrace_function - reset the ftrace function
  88  *
  89  * This NULLs the ftrace function and in essence stops
  90  * tracing.  There may be lag
  91  */
  92 void clear_ftrace_function(void)
  93 {
  94         ftrace_trace_function = ftrace_stub;
  95         __ftrace_trace_function = ftrace_stub;
  96 }
  97
  98 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
  99 /*
 100  * For those archs that do not test ftrace_trace_stop in their
 101  * mcount call site, we need to do it from C.
 102  */
 103 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
 104 {
 105         if (function_trace_stop)
 106                 return;
 107
 108         __ftrace_trace_function(ip, parent_ip);
 109 }
 110 #endif
 111
 112 static int __register_ftrace_function(struct ftrace_ops *ops)
 113 {
 114         /* should not be called from interrupt context */
 115         spin_lock(&ftrace_lock);
 116
 117         ops->next = ftrace_list;
 118         /*
 119          * We are entering ops into the ftrace_list but another
 120          * CPU might be walking that list. We need to make sure
 121          * the ops->next pointer is valid before another CPU sees
 122          * the ops pointer included into the ftrace_list.
 123          */
 124         smp_wmb();
 125         ftrace_list = ops;
 126
 127         if (ftrace_enabled) {
 128                 /*
 129                  * For one func, simply call it directly.
 130                  * For more than one func, call the chain.
 131                  */
 132 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 133                 if (ops->next == &ftrace_list_end)
 134                         ftrace_trace_function = ops->func;
 135                 else
 136                         ftrace_trace_function = ftrace_list_func;
 137 #else
 138                 if (ops->next == &ftrace_list_end)
 139                         __ftrace_trace_function = ops->func;
 140                 else
 141                         __ftrace_trace_function = ftrace_list_func;
 142                 ftrace_trace_function = ftrace_test_stop_func;
 143 #endif
 144         }
 145
 146         spin_unlock(&ftrace_lock);
 147
 148         return 0;
 149 }
 150
 151 static int __unregister_ftrace_function(struct ftrace_ops *ops)
 152 {
 153         struct ftrace_ops **p;
 154         int ret = 0;
 155
 156         /* should not be called from interrupt context */
 157         spin_lock(&ftrace_lock);
 158
 159         /*
 160          * If we are removing the last function, then simply point
 161          * to the ftrace_stub.
 162          */
 163         if (ftrace_list == ops && ops->next == &ftrace_list_end) {
 164                 ftrace_trace_function = ftrace_stub;
 165                 ftrace_list = &ftrace_list_end;
 166                 goto out;
 167         }
 168
 169         for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
 170                 if (*p == ops)
 171                         break;
 172
 173         if (*p != ops) {
 174                 ret = -1;
 175                 goto out;
 176         }
 177
 178         *p = (*p)->next;
 179
 180         if (ftrace_enabled) {
 181                 /* If we only have one func left, then call that directly */
 182                 if (ftrace_list->next == &ftrace_list_end)
 183                         ftrace_trace_function = ftrace_list->func;
 184         }
 185
 186  out:
 187         spin_unlock(&ftrace_lock);
 188
 189         return ret;
 190 }
 191
 192 #ifdef CONFIG_DYNAMIC_FTRACE
 193 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
 194 # error Dynamic ftrace depends on MCOUNT_RECORD
 195 #endif
 196
 197 /*
 198  * Since MCOUNT_ADDR may point to mcount itself, we do not want
 199  * to get it confused by reading a reference in the code as we
 200  * are parsing on objcopy output of text. Use a variable for
 201  * it instead.
 202  */
 203 static unsigned long mcount_addr = MCOUNT_ADDR;
 204
 205 enum {
 206         FTRACE_ENABLE_CALLS             = (1 << 0),
 207         FTRACE_DISABLE_CALLS            = (1 << 1),
 208         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 209         FTRACE_ENABLE_MCOUNT            = (1 << 3),
 210         FTRACE_DISABLE_MCOUNT           = (1 << 4),
 211 };
 212
 213 static int ftrace_filtered;
 214
 215 static LIST_HEAD(ftrace_new_addrs);
 216
 217 static DEFINE_MUTEX(ftrace_regex_lock);
 218
 219 struct ftrace_page {
 220         struct ftrace_page      *next;
 221         unsigned long           index;
 222         struct dyn_ftrace       records[];
 223 };
 224
 225 #define ENTRIES_PER_PAGE \
 226   ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
 227
 228 /* estimate from running different kernels */
 229 #define NR_TO_INIT              10000
 230
 231 static struct ftrace_page       *ftrace_pages_start;
 232 static struct ftrace_page       *ftrace_pages;
 233
 234 static struct dyn_ftrace *ftrace_free_records;
 235
 236
 237 #ifdef CONFIG_KPROBES
 238
 239 static int frozen_record_count;
 240
 241 static inline void freeze_record(struct dyn_ftrace *rec)
 242 {
 243         if (!(rec->flags & FTRACE_FL_FROZEN)) {
 244                 rec->flags |= FTRACE_FL_FROZEN;
 245                 frozen_record_count++;
 246         }
 247 }
 248
 249 static inline void unfreeze_record(struct dyn_ftrace *rec)
 250 {
 251         if (rec->flags & FTRACE_FL_FROZEN) {
 252                 rec->flags &= ~FTRACE_FL_FROZEN;
 253                 frozen_record_count--;
 254         }
 255 }
 256
 257 static inline int record_frozen(struct dyn_ftrace *rec)
 258 {
 259         return rec->flags & FTRACE_FL_FROZEN;
 260 }
 261 #else
 262 # define freeze_record(rec)                     ({ 0; })
 263 # define unfreeze_record(rec)                   ({ 0; })
 264 # define record_frozen(rec)                     ({ 0; })
 265 #endif /* CONFIG_KPROBES */
 266
 267 static void ftrace_free_rec(struct dyn_ftrace *rec)
 268 {
 269         rec->ip = (unsigned long)ftrace_free_records;
 270         ftrace_free_records = rec;
 271         rec->flags |= FTRACE_FL_FREE;
 272 }
 273
 274 void ftrace_release(void *start, unsigned long size)
 275 {
 276         struct dyn_ftrace *rec;
 277         struct ftrace_page *pg;
 278         unsigned long s = (unsigned long)start;
 279         unsigned long e = s + size;
 280         int i;
 281
 282         if (ftrace_disabled || !start)
 283                 return;
 284
 285         /* should not be called from interrupt context */
 286         spin_lock(&ftrace_lock);
 287
 288         for (pg = ftrace_pages_start; pg; pg = pg->next) {
 289                 for (i = 0; i < pg->index; i++) {
 290                         rec = &pg->records[i];
 291
 292                         if ((rec->ip >= s) && (rec->ip < e))
 293                                 ftrace_free_rec(rec);
 294                 }
 295         }
 296         spin_unlock(&ftrace_lock);
 297 }
 298
 299 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
 300 {
 301         struct dyn_ftrace *rec;
 302
 303         /* First check for freed records */
 304         if (ftrace_free_records) {
 305                 rec = ftrace_free_records;
 306
 307                 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
 308                         FTRACE_WARN_ON_ONCE(1);
 309                         ftrace_free_records = NULL;
 310                         return NULL;
 311                 }
 312
 313                 ftrace_free_records = (void *)rec->ip;
 314                 memset(rec, 0, sizeof(*rec));
 315                 return rec;
 316         }
 317
 318         if (ftrace_pages->index == ENTRIES_PER_PAGE) {
 319                 if (!ftrace_pages->next) {
 320                         /* allocate another page */
 321                         ftrace_pages->next =
 322                                 (void *)get_zeroed_page(GFP_KERNEL);
 323                         if (!ftrace_pages->next)
 324                                 return NULL;
 325                 }
 326                 ftrace_pages = ftrace_pages->next;
 327         }
 328
 329         return &ftrace_pages->records[ftrace_pages->index++];
 330 }
 331
 332 static struct dyn_ftrace *
 333 ftrace_record_ip(unsigned long ip)
 334 {
 335         struct dyn_ftrace *rec;
 336
 337         if (!ftrace_enabled || ftrace_disabled)
 338                 return NULL;
 339
 340         rec = ftrace_alloc_dyn_node(ip);
 341         if (!rec)
 342                 return NULL;
 343
 344         rec->ip = ip;
 345
 346         list_add(&rec->list, &ftrace_new_addrs);
 347
 348         return rec;
 349 }
 350
 351 #define FTRACE_ADDR ((long)(ftrace_caller))
 352
 353 static int
 354 __ftrace_replace_code(struct dyn_ftrace *rec,
 355                       unsigned char *old, unsigned char *new, int enable)
 356 {
 357         unsigned long ip, fl;
 358
 359         ip = rec->ip;
 360
 361         if (ftrace_filtered && enable) {
 362                 /*
 363                  * If filtering is on:
 364                  *
 365                  * If this record is set to be filtered and
 366                  * is enabled then do nothing.
 367                  *
 368                  * If this record is set to be filtered and
 369                  * it is not enabled, enable it.
 370                  *
 371                  * If this record is not set to be filtered
 372                  * and it is not enabled do nothing.
 373                  *
 374                  * If this record is set not to trace then
 375                  * do nothing.
 376                  *
 377                  * If this record is set not to trace and
 378                  * it is enabled then disable it.
 379                  *
 380                  * If this record is not set to be filtered and
 381                  * it is enabled, disable it.
 382                  */
 383
 384                 fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_NOTRACE |
 385                                    FTRACE_FL_ENABLED);
 386
 387                 if ((fl ==  (FTRACE_FL_FILTER | FTRACE_FL_ENABLED)) ||
 388                     (fl ==  (FTRACE_FL_FILTER | FTRACE_FL_NOTRACE)) ||
 389                     !fl || (fl == FTRACE_FL_NOTRACE))
 390                         return 0;
 391
 392                 /*
 393                  * If it is enabled disable it,
 394                  * otherwise enable it!
 395                  */
 396                 if (fl & FTRACE_FL_ENABLED) {
 397                         /* swap new and old */
 398                         new = old;
 399                         old = ftrace_call_replace(ip, FTRACE_ADDR);
 400                         rec->flags &= ~FTRACE_FL_ENABLED;
 401                 } else {
 402                         new = ftrace_call_replace(ip, FTRACE_ADDR);
 403                         rec->flags |= FTRACE_FL_ENABLED;
 404                 }
 405         } else {
 406
 407                 if (enable) {
 408                         /*
 409                          * If this record is set not to trace and is
 410                          * not enabled, do nothing.
 411                          */
 412                         fl = rec->flags & (FTRACE_FL_NOTRACE | FTRACE_FL_ENABLED);
 413                         if (fl == FTRACE_FL_NOTRACE)
 414                                 return 0;
 415
 416                         new = ftrace_call_replace(ip, FTRACE_ADDR);
 417                 } else
 418                         old = ftrace_call_replace(ip, FTRACE_ADDR);
 419
 420                 if (enable) {
 421                         if (rec->flags & FTRACE_FL_ENABLED)
 422                                 return 0;
 423                         rec->flags |= FTRACE_FL_ENABLED;
 424                 } else {
 425                         if (!(rec->flags & FTRACE_FL_ENABLED))
 426                                 return 0;
 427                         rec->flags &= ~FTRACE_FL_ENABLED;
 428                 }
 429         }
 430
 431         return ftrace_modify_code(ip, old, new);
 432 }
 433
 434 static void ftrace_replace_code(int enable)
 435 {
 436         int i, failed;
 437         unsigned char *new = NULL, *old = NULL;
 438         struct dyn_ftrace *rec;
 439         struct ftrace_page *pg;
 440
 441         if (enable)
 442                 old = ftrace_nop_replace();
 443         else
 444                 new = ftrace_nop_replace();
 445
 446         for (pg = ftrace_pages_start; pg; pg = pg->next) {
 447                 for (i = 0; i < pg->index; i++) {
 448                         rec = &pg->records[i];
 449
 450                         /* don't modify code that has already faulted */
 451                         if (rec->flags & FTRACE_FL_FAILED)
 452                                 continue;
 453
 454                         /* ignore updates to this record's mcount site */
 455                         if (get_kprobe((void *)rec->ip)) {
 456                                 freeze_record(rec);
 457                                 continue;
 458                         } else {
 459                                 unfreeze_record(rec);
 460                         }
 461
 462                         failed = __ftrace_replace_code(rec, old, new, enable);
 463                         if (failed && (rec->flags & FTRACE_FL_CONVERTED)) {
 464                                 rec->flags |= FTRACE_FL_FAILED;
 465                                 if ((system_state == SYSTEM_BOOTING) ||
 466                                     !core_kernel_text(rec->ip)) {
 467                                         ftrace_free_rec(rec);
 468                                 }
 469                         }
 470                 }
 471         }
 472 }
 473
 474 static void print_ip_ins(const char *fmt, unsigned char *p)
 475 {
 476         int i;
 477
 478         printk(KERN_CONT "%s", fmt);
 479
 480         for (i = 0; i < MCOUNT_INSN_SIZE; i++)
 481                 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
 482 }
 483
 484 static int
 485 ftrace_code_disable(struct dyn_ftrace *rec)
 486 {
 487         unsigned long ip;
 488         unsigned char *nop, *call;
 489         int ret;
 490
 491         ip = rec->ip;
 492
 493         nop = ftrace_nop_replace();
 494         call = ftrace_call_replace(ip, mcount_addr);
 495
 496         ret = ftrace_modify_code(ip, call, nop);
 497         if (ret) {
 498                 switch (ret) {
 499                 case -EFAULT:
 500                         FTRACE_WARN_ON_ONCE(1);
 501                         pr_info("ftrace faulted on modifying ");
 502                         print_ip_sym(ip);
 503                         break;
 504                 case -EINVAL:
 505                         FTRACE_WARN_ON_ONCE(1);
 506                         pr_info("ftrace failed to modify ");
 507                         print_ip_sym(ip);
 508                         print_ip_ins(" expected: ", call);
 509                         print_ip_ins(" actual: ", (unsigned char *)ip);
 510                         print_ip_ins(" replace: ", nop);
 511                         printk(KERN_CONT "\n");
 512                         break;
 513                 case -EPERM:
 514                         FTRACE_WARN_ON_ONCE(1);
 515                         pr_info("ftrace faulted on writing ");
 516                         print_ip_sym(ip);
 517                         break;
 518                 default:
 519                         FTRACE_WARN_ON_ONCE(1);
 520                         pr_info("ftrace faulted on unknown error ");
 521                         print_ip_sym(ip);
 522                 }
 523
 524                 rec->flags |= FTRACE_FL_FAILED;
 525                 return 0;
 526         }
 527         return 1;
 528 }
 529
 530 static int __ftrace_modify_code(void *data)
 531 {
 532         int *command = data;
 533
 534         if (*command & FTRACE_ENABLE_CALLS)
 535                 ftrace_replace_code(1);
 536         else if (*command & FTRACE_DISABLE_CALLS)
 537                 ftrace_replace_code(0);
 538
 539         if (*command & FTRACE_UPDATE_TRACE_FUNC)
 540                 ftrace_update_ftrace_func(ftrace_trace_function);
 541
 542         return 0;
 543 }
 544
 545 static void ftrace_run_update_code(int command)
 546 {
 547         stop_machine(__ftrace_modify_code, &command, NULL);
 548 }
 549
 550 static ftrace_func_t saved_ftrace_func;
 551 static int ftrace_start_up;
 552 static DEFINE_MUTEX(ftrace_start_lock);
 553
 554 static void ftrace_startup(void)
 555 {
 556         int command = 0;
 557
 558         if (unlikely(ftrace_disabled))
 559                 return;
 560
 561         mutex_lock(&ftrace_start_lock);
 562         ftrace_start_up++;
 563         if (ftrace_start_up == 1)
 564                 command |= FTRACE_ENABLE_CALLS;
 565
 566         if (saved_ftrace_func != ftrace_trace_function) {
 567                 saved_ftrace_func = ftrace_trace_function;
 568                 command |= FTRACE_UPDATE_TRACE_FUNC;
 569         }
 570
 571         if (!command || !ftrace_enabled)
 572                 goto out;
 573
 574         ftrace_run_update_code(command);
 575  out:
 576         mutex_unlock(&ftrace_start_lock);
 577 }
 578
 579 static void ftrace_shutdown(void)
 580 {
 581         int command = 0;
 582
 583         if (unlikely(ftrace_disabled))
 584                 return;
 585
 586         mutex_lock(&ftrace_start_lock);
 587         ftrace_start_up--;
 588         if (!ftrace_start_up)
 589                 command |= FTRACE_DISABLE_CALLS;
 590
 591         if (saved_ftrace_func != ftrace_trace_function) {
 592                 saved_ftrace_func = ftrace_trace_function;
 593                 command |= FTRACE_UPDATE_TRACE_FUNC;
 594         }
 595
 596         if (!command || !ftrace_enabled)
 597                 goto out;
 598
 599         ftrace_run_update_code(command);
 600  out:
 601         mutex_unlock(&ftrace_start_lock);
 602 }
 603
 604 static void ftrace_startup_sysctl(void)
 605 {
 606         int command = FTRACE_ENABLE_MCOUNT;
 607
 608         if (unlikely(ftrace_disabled))
 609                 return;
 610
 611         mutex_lock(&ftrace_start_lock);
 612         /* Force update next time */
 613         saved_ftrace_func = NULL;
 614         /* ftrace_start_up is true if we want ftrace running */
 615         if (ftrace_start_up)
 616                 command |= FTRACE_ENABLE_CALLS;
 617
 618         ftrace_run_update_code(command);
 619         mutex_unlock(&ftrace_start_lock);
 620 }
 621
 622 static void ftrace_shutdown_sysctl(void)
 623 {
 624         int command = FTRACE_DISABLE_MCOUNT;
 625
 626         if (unlikely(ftrace_disabled))
 627                 return;
 628
 629         mutex_lock(&ftrace_start_lock);
 630         /* ftrace_start_up is true if ftrace is running */
 631         if (ftrace_start_up)
 632                 command |= FTRACE_DISABLE_CALLS;
 633
 634         ftrace_run_update_code(command);
 635         mutex_unlock(&ftrace_start_lock);
 636 }
 637
 638 static cycle_t          ftrace_update_time;
 639 static unsigned long    ftrace_update_cnt;
 640 unsigned long           ftrace_update_tot_cnt;
 641
 642 static int ftrace_update_code(void)
 643 {
 644         struct dyn_ftrace *p, *t;
 645         cycle_t start, stop;
 646
 647         start = ftrace_now(raw_smp_processor_id());
 648         ftrace_update_cnt = 0;
 649
 650         list_for_each_entry_safe(p, t, &ftrace_new_addrs, list) {
 651
 652                 /* If something went wrong, bail without enabling anything */
 653                 if (unlikely(ftrace_disabled))
 654                         return -1;
 655
 656                 list_del_init(&p->list);
 657
 658                 /* convert record (i.e, patch mcount-call with NOP) */
 659                 if (ftrace_code_disable(p)) {
 660                         p->flags |= FTRACE_FL_CONVERTED;
 661                         ftrace_update_cnt++;
 662                 } else
 663                         ftrace_free_rec(p);
 664         }
 665
 666         stop = ftrace_now(raw_smp_processor_id());
 667         ftrace_update_time = stop - start;
 668         ftrace_update_tot_cnt += ftrace_update_cnt;
 669
 670         return 0;
 671 }
 672
 673 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
 674 {
 675         struct ftrace_page *pg;
 676         int cnt;
 677         int i;
 678
 679         /* allocate a few pages */
 680         ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
 681         if (!ftrace_pages_start)
 682                 return -1;
 683
 684         /*
 685          * Allocate a few more pages.
 686          *
 687          * TODO: have some parser search vmlinux before
 688          *   final linking to find all calls to ftrace.
 689          *   Then we can:
 690          *    a) know how many pages to allocate.
 691          *     and/or
 692          *    b) set up the table then.
 693          *
 694          *  The dynamic code is still necessary for
 695          *  modules.
 696          */
 697
 698         pg = ftrace_pages = ftrace_pages_start;
 699
 700         cnt = num_to_init / ENTRIES_PER_PAGE;
 701         pr_info("ftrace: allocating %ld entries in %d pages\n",
 702                 num_to_init, cnt);
 703
 704         for (i = 0; i < cnt; i++) {
 705                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
 706
 707                 /* If we fail, we'll try later anyway */
 708                 if (!pg->next)
 709                         break;
 710
 711                 pg = pg->next;
 712         }
 713
 714         return 0;
 715 }
 716
 717 enum {
 718         FTRACE_ITER_FILTER      = (1 << 0),
 719         FTRACE_ITER_CONT        = (1 << 1),
 720         FTRACE_ITER_NOTRACE     = (1 << 2),
 721         FTRACE_ITER_FAILURES    = (1 << 3),
 722 };
 723
 724 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
 725
 726 struct ftrace_iterator {
 727         loff_t                  pos;
 728         struct ftrace_page      *pg;
 729         unsigned                idx;
 730         unsigned                flags;
 731         unsigned char           buffer[FTRACE_BUFF_MAX+1];
 732         unsigned                buffer_idx;
 733         unsigned                filtered;
 734 };
 735
 736 static void *
 737 t_next(struct seq_file *m, void *v, loff_t *pos)
 738 {
 739         struct ftrace_iterator *iter = m->private;
 740         struct dyn_ftrace *rec = NULL;
 741
 742         (*pos)++;
 743
 744         /* should not be called from interrupt context */
 745         spin_lock(&ftrace_lock);
 746  retry:
 747         if (iter->idx >= iter->pg->index) {
 748                 if (iter->pg->next) {
 749                         iter->pg = iter->pg->next;
 750                         iter->idx = 0;
 751                         goto retry;
 752                 }
 753         } else {
 754                 rec = &iter->pg->records[iter->idx++];
 755                 if ((rec->flags & FTRACE_FL_FREE) ||
 756
 757                     (!(iter->flags & FTRACE_ITER_FAILURES) &&
 758                      (rec->flags & FTRACE_FL_FAILED)) ||
 759
 760                     ((iter->flags & FTRACE_ITER_FAILURES) &&
 761                      !(rec->flags & FTRACE_FL_FAILED)) ||
 762
 763                     ((iter->flags & FTRACE_ITER_FILTER) &&
 764                      !(rec->flags & FTRACE_FL_FILTER)) ||
 765
 766                     ((iter->flags & FTRACE_ITER_NOTRACE) &&
 767                      !(rec->flags & FTRACE_FL_NOTRACE))) {
 768                         rec = NULL;
 769                         goto retry;
 770                 }
 771         }
 772         spin_unlock(&ftrace_lock);
 773
 774         iter->pos = *pos;
 775
 776         return rec;
 777 }
 778
 779 static void *t_start(struct seq_file *m, loff_t *pos)
 780 {
 781         struct ftrace_iterator *iter = m->private;
 782         void *p = NULL;
 783         loff_t l = -1;
 784
 785         if (*pos != iter->pos) {
 786                 for (p = t_next(m, p, &l); p && l < *pos; p = t_next(m, p, &l))
 787                         ;
 788         } else {
 789                 l = *pos;
 790                 p = t_next(m, p, &l);
 791         }
 792
 793         return p;
 794 }
 795
 796 static void t_stop(struct seq_file *m, void *p)
 797 {
 798 }
 799
 800 static int t_show(struct seq_file *m, void *v)
 801 {
 802         struct dyn_ftrace *rec = v;
 803         char str[KSYM_SYMBOL_LEN];
 804
 805         if (!rec)
 806                 return 0;
 807
 808         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 809
 810         seq_printf(m, "%s\n", str);
 811
 812         return 0;
 813 }
 814
 815 static struct seq_operations show_ftrace_seq_ops = {
 816         .start = t_start,
 817         .next = t_next,
 818         .stop = t_stop,
 819         .show = t_show,
 820 };
 821
 822 static int
 823 ftrace_avail_open(struct inode *inode, struct file *file)
 824 {
 825         struct ftrace_iterator *iter;
 826         int ret;
 827
 828         if (unlikely(ftrace_disabled))
 829                 return -ENODEV;
 830
 831         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
 832         if (!iter)
 833                 return -ENOMEM;
 834
 835         iter->pg = ftrace_pages_start;
 836         iter->pos = -1;
 837
 838         ret = seq_open(file, &show_ftrace_seq_ops);
 839         if (!ret) {
 840                 struct seq_file *m = file->private_data;
 841
 842                 m->private = iter;
 843         } else {
 844                 kfree(iter);
 845         }
 846
 847         return ret;
 848 }
 849
 850 int ftrace_avail_release(struct inode *inode, struct file *file)
 851 {
 852         struct seq_file *m = (struct seq_file *)file->private_data;
 853         struct ftrace_iterator *iter = m->private;
 854
 855         seq_release(inode, file);
 856         kfree(iter);
 857
 858         return 0;
 859 }
 860
 861 static int
 862 ftrace_failures_open(struct inode *inode, struct file *file)
 863 {
 864         int ret;
 865         struct seq_file *m;
 866         struct ftrace_iterator *iter;
 867
 868         ret = ftrace_avail_open(inode, file);
 869         if (!ret) {
 870                 m = (struct seq_file *)file->private_data;
 871                 iter = (struct ftrace_iterator *)m->private;
 872                 iter->flags = FTRACE_ITER_FAILURES;
 873         }
 874
 875         return ret;
 876 }
 877
 878
 879 static void ftrace_filter_reset(int enable)
 880 {
 881         struct ftrace_page *pg;
 882         struct dyn_ftrace *rec;
 883         unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
 884         unsigned i;
 885
 886         /* should not be called from interrupt context */
 887         spin_lock(&ftrace_lock);
 888         if (enable)
 889                 ftrace_filtered = 0;
 890         pg = ftrace_pages_start;
 891         while (pg) {
 892                 for (i = 0; i < pg->index; i++) {
 893                         rec = &pg->records[i];
 894                         if (rec->flags & FTRACE_FL_FAILED)
 895                                 continue;
 896                         rec->flags &= ~type;
 897                 }
 898                 pg = pg->next;
 899         }
 900         spin_unlock(&ftrace_lock);
 901 }
 902
 903 static int
 904 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
 905 {
 906         struct ftrace_iterator *iter;
 907         int ret = 0;
 908
 909         if (unlikely(ftrace_disabled))
 910                 return -ENODEV;
 911
 912         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
 913         if (!iter)
 914                 return -ENOMEM;
 915
 916         mutex_lock(&ftrace_regex_lock);
 917         if ((file->f_mode & FMODE_WRITE) &&
 918             !(file->f_flags & O_APPEND))
 919                 ftrace_filter_reset(enable);
 920
 921         if (file->f_mode & FMODE_READ) {
 922                 iter->pg = ftrace_pages_start;
 923                 iter->pos = -1;
 924                 iter->flags = enable ? FTRACE_ITER_FILTER :
 925                         FTRACE_ITER_NOTRACE;
 926
 927                 ret = seq_open(file, &show_ftrace_seq_ops);
 928                 if (!ret) {
 929                         struct seq_file *m = file->private_data;
 930                         m->private = iter;
 931                 } else
 932                         kfree(iter);
 933         } else
 934                 file->private_data = iter;
 935         mutex_unlock(&ftrace_regex_lock);
 936
 937         return ret;
 938 }
 939
 940 static int
 941 ftrace_filter_open(struct inode *inode, struct file *file)
 942 {
 943         return ftrace_regex_open(inode, file, 1);
 944 }
 945
 946 static int
 947 ftrace_notrace_open(struct inode *inode, struct file *file)
 948 {
 949         return ftrace_regex_open(inode, file, 0);
 950 }
 951
 952 static ssize_t
 953 ftrace_regex_read(struct file *file, char __user *ubuf,
 954                        size_t cnt, loff_t *ppos)
 955 {
 956         if (file->f_mode & FMODE_READ)
 957                 return seq_read(file, ubuf, cnt, ppos);
 958         else
 959                 return -EPERM;
 960 }
 961
 962 static loff_t
 963 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
 964 {
 965         loff_t ret;
 966
 967         if (file->f_mode & FMODE_READ)
 968                 ret = seq_lseek(file, offset, origin);
 969         else
 970                 file->f_pos = ret = 1;
 971
 972         return ret;
 973 }
 974
 975 enum {
 976         MATCH_FULL,
 977         MATCH_FRONT_ONLY,
 978         MATCH_MIDDLE_ONLY,
 979         MATCH_END_ONLY,
 980 };
 981
 982 static void
 983 ftrace_match(unsigned char *buff, int len, int enable)
 984 {
 985         char str[KSYM_SYMBOL_LEN];
 986         char *search = NULL;
 987         struct ftrace_page *pg;
 988         struct dyn_ftrace *rec;
 989         int type = MATCH_FULL;
 990         unsigned long flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
 991         unsigned i, match = 0, search_len = 0;
 992
 993         for (i = 0; i < len; i++) {
 994                 if (buff[i] == '*') {
 995                         if (!i) {
 996                                 search = buff + i + 1;
 997                                 type = MATCH_END_ONLY;
 998                                 search_len = len - (i + 1);
 999                         } else {
1000                                 if (type == MATCH_END_ONLY) {
1001                                         type = MATCH_MIDDLE_ONLY;
1002                                 } else {
1003                                         match = i;
1004                                         type = MATCH_FRONT_ONLY;
1005                                 }
1006                                 buff[i] = 0;
1007                                 break;
1008                         }
1009                 }
1010         }
1011
1012         /* should not be called from interrupt context */
1013         spin_lock(&ftrace_lock);
1014         if (enable)
1015                 ftrace_filtered = 1;
1016         pg = ftrace_pages_start;
1017         while (pg) {
1018                 for (i = 0; i < pg->index; i++) {
1019                         int matched = 0;
1020                         char *ptr;
1021
1022                         rec = &pg->records[i];
1023                         if (rec->flags & FTRACE_FL_FAILED)
1024                                 continue;
1025                         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1026                         switch (type) {
1027                         case MATCH_FULL:
1028                                 if (strcmp(str, buff) == 0)
1029                                         matched = 1;
1030                                 break;
1031                         case MATCH_FRONT_ONLY:
1032                                 if (memcmp(str, buff, match) == 0)
1033                                         matched = 1;
1034                                 break;
1035                         case MATCH_MIDDLE_ONLY:
1036                                 if (strstr(str, search))
1037                                         matched = 1;
1038                                 break;
1039                         case MATCH_END_ONLY:
1040                                 ptr = strstr(str, search);
1041                                 if (ptr && (ptr[search_len] == 0))
1042                                         matched = 1;
1043                                 break;
1044                         }
1045                         if (matched)
1046                                 rec->flags |= flag;
1047                 }
1048                 pg = pg->next;
1049         }
1050         spin_unlock(&ftrace_lock);
1051 }
1052
1053 static ssize_t
1054 ftrace_regex_write(struct file *file, const char __user *ubuf,
1055                    size_t cnt, loff_t *ppos, int enable)
1056 {
1057         struct ftrace_iterator *iter;
1058         char ch;
1059         size_t read = 0;
1060         ssize_t ret;
1061
1062         if (!cnt || cnt < 0)
1063                 return 0;
1064
1065         mutex_lock(&ftrace_regex_lock);
1066
1067         if (file->f_mode & FMODE_READ) {
1068                 struct seq_file *m = file->private_data;
1069                 iter = m->private;
1070         } else
1071                 iter = file->private_data;
1072
1073         if (!*ppos) {
1074                 iter->flags &= ~FTRACE_ITER_CONT;
1075                 iter->buffer_idx = 0;
1076         }
1077
1078         ret = get_user(ch, ubuf++);
1079         if (ret)
1080                 goto out;
1081         read++;
1082         cnt--;
1083
1084         if (!(iter->flags & ~FTRACE_ITER_CONT)) {
1085                 /* skip white space */
1086                 while (cnt && isspace(ch)) {
1087                         ret = get_user(ch, ubuf++);
1088                         if (ret)
1089                                 goto out;
1090                         read++;
1091                         cnt--;
1092                 }
1093
1094                 if (isspace(ch)) {
1095                         file->f_pos += read;
1096                         ret = read;
1097                         goto out;
1098                 }
1099
1100                 iter->buffer_idx = 0;
1101         }
1102
1103         while (cnt && !isspace(ch)) {
1104                 if (iter->buffer_idx < FTRACE_BUFF_MAX)
1105                         iter->buffer[iter->buffer_idx++] = ch;
1106                 else {
1107                         ret = -EINVAL;
1108                         goto out;
1109                 }
1110                 ret = get_user(ch, ubuf++);
1111                 if (ret)
1112                         goto out;
1113                 read++;
1114                 cnt--;
1115         }
1116
1117         if (isspace(ch)) {
1118                 iter->filtered++;
1119                 iter->buffer[iter->buffer_idx] = 0;
1120                 ftrace_match(iter->buffer, iter->buffer_idx, enable);
1121                 iter->buffer_idx = 0;
1122         } else
1123                 iter->flags |= FTRACE_ITER_CONT;
1124
1125
1126         file->f_pos += read;
1127
1128         ret = read;
1129  out:
1130         mutex_unlock(&ftrace_regex_lock);
1131
1132         return ret;
1133 }
1134
1135 static ssize_t
1136 ftrace_filter_write(struct file *file, const char __user *ubuf,
1137                     size_t cnt, loff_t *ppos)
1138 {
1139         return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
1140 }
1141
1142 static ssize_t
1143 ftrace_notrace_write(struct file *file, const char __user *ubuf,
1144                      size_t cnt, loff_t *ppos)
1145 {
1146         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
1147 }
1148
1149 static void
1150 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
1151 {
1152         if (unlikely(ftrace_disabled))
1153                 return;
1154
1155         mutex_lock(&ftrace_regex_lock);
1156         if (reset)
1157                 ftrace_filter_reset(enable);
1158         if (buf)
1159                 ftrace_match(buf, len, enable);
1160         mutex_unlock(&ftrace_regex_lock);
1161 }
1162
1163 /**
1164  * ftrace_set_filter - set a function to filter on in ftrace
1165  * @buf - the string that holds the function filter text.
1166  * @len - the length of the string.
1167  * @reset - non zero to reset all filters before applying this filter.
1168  *
1169  * Filters denote which functions should be enabled when tracing is enabled.
1170  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
1171  */
1172 void ftrace_set_filter(unsigned char *buf, int len, int reset)
1173 {
1174         ftrace_set_regex(buf, len, reset, 1);
1175 }
1176
1177 /**
1178  * ftrace_set_notrace - set a function to not trace in ftrace
1179  * @buf - the string that holds the function notrace text.
1180  * @len - the length of the string.
1181  * @reset - non zero to reset all filters before applying this filter.
1182  *
1183  * Notrace Filters denote which functions should not be enabled when tracing
1184  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
1185  * for tracing.
1186  */
1187 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
1188 {
1189         ftrace_set_regex(buf, len, reset, 0);
1190 }
1191
1192 static int
1193 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
1194 {
1195         struct seq_file *m = (struct seq_file *)file->private_data;
1196         struct ftrace_iterator *iter;
1197
1198         mutex_lock(&ftrace_regex_lock);
1199         if (file->f_mode & FMODE_READ) {
1200                 iter = m->private;
1201
1202                 seq_release(inode, file);
1203         } else
1204                 iter = file->private_data;
1205
1206         if (iter->buffer_idx) {
1207                 iter->filtered++;
1208                 iter->buffer[iter->buffer_idx] = 0;
1209                 ftrace_match(iter->buffer, iter->buffer_idx, enable);
1210         }
1211
1212         mutex_lock(&ftrace_sysctl_lock);
1213         mutex_lock(&ftrace_start_lock);
1214         if (iter->filtered && ftrace_start_up && ftrace_enabled)
1215                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
1216         mutex_unlock(&ftrace_start_lock);
1217         mutex_unlock(&ftrace_sysctl_lock);
1218
1219         kfree(iter);
1220         mutex_unlock(&ftrace_regex_lock);
1221         return 0;
1222 }
1223
1224 static int
1225 ftrace_filter_release(struct inode *inode, struct file *file)
1226 {
1227         return ftrace_regex_release(inode, file, 1);
1228 }
1229
1230 static int
1231 ftrace_notrace_release(struct inode *inode, struct file *file)
1232 {
1233         return ftrace_regex_release(inode, file, 0);
1234 }
1235
1236 static struct file_operations ftrace_avail_fops = {
1237         .open = ftrace_avail_open,
1238         .read = seq_read,
1239         .llseek = seq_lseek,
1240         .release = ftrace_avail_release,
1241 };
1242
1243 static struct file_operations ftrace_failures_fops = {
1244         .open = ftrace_failures_open,
1245         .read = seq_read,
1246         .llseek = seq_lseek,
1247         .release = ftrace_avail_release,
1248 };
1249
1250 static struct file_operations ftrace_filter_fops = {
1251         .open = ftrace_filter_open,
1252         .read = ftrace_regex_read,
1253         .write = ftrace_filter_write,
1254         .llseek = ftrace_regex_lseek,
1255         .release = ftrace_filter_release,
1256 };
1257
1258 static struct file_operations ftrace_notrace_fops = {
1259         .open = ftrace_notrace_open,
1260         .read = ftrace_regex_read,
1261         .write = ftrace_notrace_write,
1262         .llseek = ftrace_regex_lseek,
1263         .release = ftrace_notrace_release,
1264 };
1265
1266 static __init int ftrace_init_debugfs(void)
1267 {
1268         struct dentry *d_tracer;
1269         struct dentry *entry;
1270
1271         d_tracer = tracing_init_dentry();
1272
1273         entry = debugfs_create_file("available_filter_functions", 0444,
1274                                     d_tracer, NULL, &ftrace_avail_fops);
1275         if (!entry)
1276                 pr_warning("Could not create debugfs "
1277                            "'available_filter_functions' entry\n");
1278
1279         entry = debugfs_create_file("failures", 0444,
1280                                     d_tracer, NULL, &ftrace_failures_fops);
1281         if (!entry)
1282                 pr_warning("Could not create debugfs 'failures' entry\n");
1283
1284         entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer,
1285                                     NULL, &ftrace_filter_fops);
1286         if (!entry)
1287                 pr_warning("Could not create debugfs "
1288                            "'set_ftrace_filter' entry\n");
1289
1290         entry = debugfs_create_file("set_ftrace_notrace", 0644, d_tracer,
1291                                     NULL, &ftrace_notrace_fops);
1292         if (!entry)
1293                 pr_warning("Could not create debugfs "
1294                            "'set_ftrace_notrace' entry\n");
1295
1296         return 0;
1297 }
1298
1299 fs_initcall(ftrace_init_debugfs);
1300
1301 static int ftrace_convert_nops(unsigned long *start,
1302                                unsigned long *end)
1303 {
1304         unsigned long *p;
1305         unsigned long addr;
1306         unsigned long flags;
1307
1308         mutex_lock(&ftrace_start_lock);
1309         p = start;
1310         while (p < end) {
1311                 addr = ftrace_call_adjust(*p++);
1312                 ftrace_record_ip(addr);
1313         }
1314
1315         /* disable interrupts to prevent kstop machine */
1316         local_irq_save(flags);
1317         ftrace_update_code();
1318         local_irq_restore(flags);
1319         mutex_unlock(&ftrace_start_lock);
1320
1321         return 0;
1322 }
1323
1324 void ftrace_init_module(unsigned long *start, unsigned long *end)
1325 {
1326         if (ftrace_disabled || start == end)
1327                 return;
1328         ftrace_convert_nops(start, end);
1329 }
1330
1331 extern unsigned long __start_mcount_loc[];
1332 extern unsigned long __stop_mcount_loc[];
1333
1334 void __init ftrace_init(void)
1335 {
1336         unsigned long count, addr, flags;
1337         int ret;
1338
1339         /* Keep the ftrace pointer to the stub */
1340         addr = (unsigned long)ftrace_stub;
1341
1342         local_irq_save(flags);
1343         ftrace_dyn_arch_init(&addr);
1344         local_irq_restore(flags);
1345
1346         /* ftrace_dyn_arch_init places the return code in addr */
1347         if (addr)
1348                 goto failed;
1349
1350         count = __stop_mcount_loc - __start_mcount_loc;
1351
1352         ret = ftrace_dyn_table_alloc(count);
1353         if (ret)
1354                 goto failed;
1355
1356         last_ftrace_enabled = ftrace_enabled = 1;
1357
1358         ret = ftrace_convert_nops(__start_mcount_loc,
1359                                   __stop_mcount_loc);
1360
1361         return;
1362  failed:
1363         ftrace_disabled = 1;
1364 }
1365
1366 #else
1367
1368 static int __init ftrace_nodyn_init(void)
1369 {
1370         ftrace_enabled = 1;
1371         return 0;
1372 }
1373 device_initcall(ftrace_nodyn_init);
1374
1375 # define ftrace_startup()               do { } while (0)
1376 # define ftrace_shutdown()              do { } while (0)
1377 # define ftrace_startup_sysctl()        do { } while (0)
1378 # define ftrace_shutdown_sysctl()       do { } while (0)
1379 #endif /* CONFIG_DYNAMIC_FTRACE */
1380
1381 /**
1382  * ftrace_kill - kill ftrace
1383  *
1384  * This function should be used by panic code. It stops ftrace
1385  * but in a not so nice way. If you need to simply kill ftrace
1386  * from a non-atomic section, use ftrace_kill.
1387  */
1388 void ftrace_kill(void)
1389 {
1390         ftrace_disabled = 1;
1391         ftrace_enabled = 0;
1392         clear_ftrace_function();
1393 }
1394
1395 /**
1396  * register_ftrace_function - register a function for profiling
1397  * @ops - ops structure that holds the function for profiling.
1398  *
1399  * Register a function to be called by all functions in the
1400  * kernel.
1401  *
1402  * Note: @ops->func and all the functions it calls must be labeled
1403  *       with "notrace", otherwise it will go into a
1404  *       recursive loop.
1405  */
1406 int register_ftrace_function(struct ftrace_ops *ops)
1407 {
1408         int ret;
1409
1410         if (unlikely(ftrace_disabled))
1411                 return -1;
1412
1413         mutex_lock(&ftrace_sysctl_lock);
1414         ret = __register_ftrace_function(ops);
1415         ftrace_startup();
1416         mutex_unlock(&ftrace_sysctl_lock);
1417
1418         return ret;
1419 }
1420
1421 /**
1422  * unregister_ftrace_function - unresgister a function for profiling.
1423  * @ops - ops structure that holds the function to unregister
1424  *
1425  * Unregister a function that was added to be called by ftrace profiling.
1426  */
1427 int unregister_ftrace_function(struct ftrace_ops *ops)
1428 {
1429         int ret;
1430
1431         mutex_lock(&ftrace_sysctl_lock);
1432         ret = __unregister_ftrace_function(ops);
1433         ftrace_shutdown();
1434         mutex_unlock(&ftrace_sysctl_lock);
1435
1436         return ret;
1437 }
1438
1439 int
1440 ftrace_enable_sysctl(struct ctl_table *table, int write,
1441                      struct file *file, void __user *buffer, size_t *lenp,
1442                      loff_t *ppos)
1443 {
1444         int ret;
1445
1446         if (unlikely(ftrace_disabled))
1447                 return -ENODEV;
1448
1449         mutex_lock(&ftrace_sysctl_lock);
1450
1451         ret  = proc_dointvec(table, write, file, buffer, lenp, ppos);
1452
1453         if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
1454                 goto out;
1455
1456         last_ftrace_enabled = ftrace_enabled;
1457
1458         if (ftrace_enabled) {
1459
1460                 ftrace_startup_sysctl();
1461
1462                 /* we are starting ftrace again */
1463                 if (ftrace_list != &ftrace_list_end) {
1464                         if (ftrace_list->next == &ftrace_list_end)
1465                                 ftrace_trace_function = ftrace_list->func;
1466                         else
1467                                 ftrace_trace_function = ftrace_list_func;
1468                 }
1469
1470         } else {
1471                 /* stopping ftrace calls (just send to ftrace_stub) */
1472                 ftrace_trace_function = ftrace_stub;
1473
1474                 ftrace_shutdown_sysctl();
1475         }
1476
1477  out:
1478         mutex_unlock(&ftrace_sysctl_lock);
1479         return ret;
1480 }
1481
1482 #ifdef CONFIG_FUNCTION_RET_TRACER
1483 trace_function_return_t ftrace_function_return =
1484                         (trace_function_return_t)ftrace_stub;
1485 void register_ftrace_return(trace_function_return_t func)
1486 {
1487         ftrace_function_return = func;
1488 }
1489
1490 void unregister_ftrace_return(void)
1491 {
1492         ftrace_function_return = (trace_function_return_t)ftrace_stub;
1493 }
1494 #endif
1495
1496
1497