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