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/hash.h>
  29 #include <linux/list.h>
  30
  31 #include <asm/ftrace.h>
  32
  33 #include "trace.h"
  34
  35 /* ftrace_enabled is a method to turn ftrace on or off */
  36 int ftrace_enabled __read_mostly;
  37 static int last_ftrace_enabled;
  38
  39 /*
  40  * ftrace_disabled is set when an anomaly is discovered.
  41  * ftrace_disabled is much stronger than ftrace_enabled.
  42  */
  43 static int ftrace_disabled __read_mostly;
  44
  45 static DEFINE_SPINLOCK(ftrace_lock);
  46 static DEFINE_MUTEX(ftrace_sysctl_lock);
  47
  48 static struct ftrace_ops ftrace_list_end __read_mostly =
  49 {
  50         .func = ftrace_stub,
  51 };
  52
  53 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
  54 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
  55
  56 static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
  57 {
  58         struct ftrace_ops *op = ftrace_list;
  59
  60         /* in case someone actually ports this to alpha! */
  61         read_barrier_depends();
  62
  63         while (op != &ftrace_list_end) {
  64                 /* silly alpha */
  65                 read_barrier_depends();
  66                 op->func(ip, parent_ip);
  67                 op = op->next;
  68         };
  69 }
  70
  71 /**
  72  * clear_ftrace_function - reset the ftrace function
  73  *
  74  * This NULLs the ftrace function and in essence stops
  75  * tracing.  There may be lag
  76  */
  77 void clear_ftrace_function(void)
  78 {
  79         ftrace_trace_function = ftrace_stub;
  80 }
  81
  82 static int __register_ftrace_function(struct ftrace_ops *ops)
  83 {
  84         /* should not be called from interrupt context */
  85         spin_lock(&ftrace_lock);
  86
  87         ops->next = ftrace_list;
  88         /*
  89          * We are entering ops into the ftrace_list but another
  90          * CPU might be walking that list. We need to make sure
  91          * the ops->next pointer is valid before another CPU sees
  92          * the ops pointer included into the ftrace_list.
  93          */
  94         smp_wmb();
  95         ftrace_list = ops;
  96
  97         if (ftrace_enabled) {
  98                 /*
  99                  * For one func, simply call it directly.
 100                  * For more than one func, call the chain.
 101                  */
 102                 if (ops->next == &ftrace_list_end)
 103                         ftrace_trace_function = ops->func;
 104                 else
 105                         ftrace_trace_function = ftrace_list_func;
 106         }
 107
 108         spin_unlock(&ftrace_lock);
 109
 110         return 0;
 111 }
 112
 113 static int __unregister_ftrace_function(struct ftrace_ops *ops)
 114 {
 115         struct ftrace_ops **p;
 116         int ret = 0;
 117
 118         /* should not be called from interrupt context */
 119         spin_lock(&ftrace_lock);
 120
 121         /*
 122          * If we are removing the last function, then simply point
 123          * to the ftrace_stub.
 124          */
 125         if (ftrace_list == ops && ops->next == &ftrace_list_end) {
 126                 ftrace_trace_function = ftrace_stub;
 127                 ftrace_list = &ftrace_list_end;
 128                 goto out;
 129         }
 130
 131         for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
 132                 if (*p == ops)
 133                         break;
 134
 135         if (*p != ops) {
 136                 ret = -1;
 137                 goto out;
 138         }
 139
 140         *p = (*p)->next;
 141
 142         if (ftrace_enabled) {
 143                 /* If we only have one func left, then call that directly */
 144                 if (ftrace_list == &ftrace_list_end ||
 145                     ftrace_list->next == &ftrace_list_end)
 146                         ftrace_trace_function = ftrace_list->func;
 147         }
 148
 149  out:
 150         spin_unlock(&ftrace_lock);
 151
 152         return ret;
 153 }
 154
 155 #ifdef CONFIG_DYNAMIC_FTRACE
 156
 157 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
 158 /*
 159  * The hash lock is only needed when the recording of the mcount
 160  * callers are dynamic. That is, by the caller themselves and
 161  * not recorded via the compilation.
 162  */
 163 static DEFINE_SPINLOCK(ftrace_hash_lock);
 164 #define ftrace_hash_lock(flags)   spin_lock_irqsave(&ftrace_hash_lock, flags)
 165 #define ftrace_hash_unlock(flags) \
 166                         spin_unlock_irqrestore(&ftrace_hash_lock, flags)
 167 static void ftrace_release_hash(unsigned long start, unsigned long end);
 168 #else
 169 /* This is protected via the ftrace_lock with MCOUNT_RECORD. */
 170 #define ftrace_hash_lock(flags)   do { (void)(flags); } while (0)
 171 #define ftrace_hash_unlock(flags) do { } while(0)
 172 static inline void ftrace_release_hash(unsigned long start, unsigned long end)
 173 {
 174 }
 175 #endif
 176
 177 /*
 178  * Since MCOUNT_ADDR may point to mcount itself, we do not want
 179  * to get it confused by reading a reference in the code as we
 180  * are parsing on objcopy output of text. Use a variable for
 181  * it instead.
 182  */
 183 static unsigned long mcount_addr = MCOUNT_ADDR;
 184
 185 static struct task_struct *ftraced_task;
 186
 187 enum {
 188         FTRACE_ENABLE_CALLS             = (1 << 0),
 189         FTRACE_DISABLE_CALLS            = (1 << 1),
 190         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 191         FTRACE_ENABLE_MCOUNT            = (1 << 3),
 192         FTRACE_DISABLE_MCOUNT           = (1 << 4),
 193 };
 194
 195 static int ftrace_filtered;
 196 static int tracing_on;
 197 static int frozen_record_count;
 198
 199 static struct hlist_head ftrace_hash[FTRACE_HASHSIZE];
 200
 201 static DEFINE_PER_CPU(int, ftrace_shutdown_disable_cpu);
 202
 203 static DEFINE_MUTEX(ftraced_lock);
 204 static DEFINE_MUTEX(ftrace_regex_lock);
 205
 206 struct ftrace_page {
 207         struct ftrace_page      *next;
 208         unsigned long           index;
 209         struct dyn_ftrace       records[];
 210 };
 211
 212 #define ENTRIES_PER_PAGE \
 213   ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
 214
 215 /* estimate from running different kernels */
 216 #define NR_TO_INIT              10000
 217
 218 static struct ftrace_page       *ftrace_pages_start;
 219 static struct ftrace_page       *ftrace_pages;
 220
 221 static int ftraced_trigger;
 222 static int ftraced_suspend;
 223 static int ftraced_stop;
 224
 225 static int ftrace_record_suspend;
 226
 227 static struct dyn_ftrace *ftrace_free_records;
 228
 229
 230 #ifdef CONFIG_KPROBES
 231 static inline void freeze_record(struct dyn_ftrace *rec)
 232 {
 233         if (!(rec->flags & FTRACE_FL_FROZEN)) {
 234                 rec->flags |= FTRACE_FL_FROZEN;
 235                 frozen_record_count++;
 236         }
 237 }
 238
 239 static inline void unfreeze_record(struct dyn_ftrace *rec)
 240 {
 241         if (rec->flags & FTRACE_FL_FROZEN) {
 242                 rec->flags &= ~FTRACE_FL_FROZEN;
 243                 frozen_record_count--;
 244         }
 245 }
 246
 247 static inline int record_frozen(struct dyn_ftrace *rec)
 248 {
 249         return rec->flags & FTRACE_FL_FROZEN;
 250 }
 251 #else
 252 # define freeze_record(rec)                     ({ 0; })
 253 # define unfreeze_record(rec)                   ({ 0; })
 254 # define record_frozen(rec)                     ({ 0; })
 255 #endif /* CONFIG_KPROBES */
 256
 257 int skip_trace(unsigned long ip)
 258 {
 259         unsigned long fl;
 260         struct dyn_ftrace *rec;
 261         struct hlist_node *t;
 262         struct hlist_head *head;
 263
 264         if (frozen_record_count == 0)
 265                 return 0;
 266
 267         head = &ftrace_hash[hash_long(ip, FTRACE_HASHBITS)];
 268         hlist_for_each_entry_rcu(rec, t, head, node) {
 269                 if (rec->ip == ip) {
 270                         if (record_frozen(rec)) {
 271                                 if (rec->flags & FTRACE_FL_FAILED)
 272                                         return 1;
 273
 274                                 if (!(rec->flags & FTRACE_FL_CONVERTED))
 275                                         return 1;
 276
 277                                 if (!tracing_on || !ftrace_enabled)
 278                                         return 1;
 279
 280                                 if (ftrace_filtered) {
 281                                         fl = rec->flags & (FTRACE_FL_FILTER |
 282                                                            FTRACE_FL_NOTRACE);
 283                                         if (!fl || (fl & FTRACE_FL_NOTRACE))
 284                                                 return 1;
 285                                 }
 286                         }
 287                         break;
 288                 }
 289         }
 290
 291         return 0;
 292 }
 293
 294 static inline int
 295 ftrace_ip_in_hash(unsigned long ip, unsigned long key)
 296 {
 297         struct dyn_ftrace *p;
 298         struct hlist_node *t;
 299         int found = 0;
 300
 301         hlist_for_each_entry_rcu(p, t, &ftrace_hash[key], node) {
 302                 if (p->ip == ip) {
 303                         found = 1;
 304                         break;
 305                 }
 306         }
 307
 308         return found;
 309 }
 310
 311 static inline void
 312 ftrace_add_hash(struct dyn_ftrace *node, unsigned long key)
 313 {
 314         hlist_add_head_rcu(&node->node, &ftrace_hash[key]);
 315 }
 316
 317 /* called from kstop_machine */
 318 static inline void ftrace_del_hash(struct dyn_ftrace *node)
 319 {
 320         hlist_del(&node->node);
 321 }
 322
 323 static void ftrace_free_rec(struct dyn_ftrace *rec)
 324 {
 325         rec->ip = (unsigned long)ftrace_free_records;
 326         ftrace_free_records = rec;
 327         rec->flags |= FTRACE_FL_FREE;
 328 }
 329
 330 void ftrace_release(void *start, unsigned long size)
 331 {
 332         struct dyn_ftrace *rec;
 333         struct ftrace_page *pg;
 334         unsigned long s = (unsigned long)start;
 335         unsigned long e = s + size;
 336         int i;
 337
 338         if (ftrace_disabled || !start)
 339                 return;
 340
 341         /* should not be called from interrupt context */
 342         spin_lock(&ftrace_lock);
 343
 344         for (pg = ftrace_pages_start; pg; pg = pg->next) {
 345                 for (i = 0; i < pg->index; i++) {
 346                         rec = &pg->records[i];
 347
 348                         if ((rec->ip >= s) && (rec->ip < e))
 349                                 ftrace_free_rec(rec);
 350                 }
 351         }
 352         spin_unlock(&ftrace_lock);
 353
 354         ftrace_release_hash(s, e);
 355 }
 356
 357 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
 358 {
 359         struct dyn_ftrace *rec;
 360
 361         /* First check for freed records */
 362         if (ftrace_free_records) {
 363                 rec = ftrace_free_records;
 364
 365                 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
 366                         WARN_ON_ONCE(1);
 367                         ftrace_free_records = NULL;
 368                         ftrace_disabled = 1;
 369                         ftrace_enabled = 0;
 370                         return NULL;
 371                 }
 372
 373                 ftrace_free_records = (void *)rec->ip;
 374                 memset(rec, 0, sizeof(*rec));
 375                 return rec;
 376         }
 377
 378         if (ftrace_pages->index == ENTRIES_PER_PAGE) {
 379                 if (!ftrace_pages->next)
 380                         return NULL;
 381                 ftrace_pages = ftrace_pages->next;
 382         }
 383
 384         return &ftrace_pages->records[ftrace_pages->index++];
 385 }
 386
 387 static void
 388 ftrace_record_ip(unsigned long ip)
 389 {
 390         struct dyn_ftrace *node;
 391         unsigned long flags;
 392         unsigned long key;
 393         int resched;
 394         int cpu;
 395
 396         if (!ftrace_enabled || ftrace_disabled)
 397                 return;
 398
 399         resched = need_resched();
 400         preempt_disable_notrace();
 401
 402         /*
 403          * We simply need to protect against recursion.
 404          * Use the the raw version of smp_processor_id and not
 405          * __get_cpu_var which can call debug hooks that can
 406          * cause a recursive crash here.
 407          */
 408         cpu = raw_smp_processor_id();
 409         per_cpu(ftrace_shutdown_disable_cpu, cpu)++;
 410         if (per_cpu(ftrace_shutdown_disable_cpu, cpu) != 1)
 411                 goto out;
 412
 413         if (unlikely(ftrace_record_suspend))
 414                 goto out;
 415
 416         key = hash_long(ip, FTRACE_HASHBITS);
 417
 418         WARN_ON_ONCE(key >= FTRACE_HASHSIZE);
 419
 420         if (ftrace_ip_in_hash(ip, key))
 421                 goto out;
 422
 423         ftrace_hash_lock(flags);
 424
 425         /* This ip may have hit the hash before the lock */
 426         if (ftrace_ip_in_hash(ip, key))
 427                 goto out_unlock;
 428
 429         node = ftrace_alloc_dyn_node(ip);
 430         if (!node)
 431                 goto out_unlock;
 432
 433         node->ip = ip;
 434
 435         ftrace_add_hash(node, key);
 436
 437         ftraced_trigger = 1;
 438
 439  out_unlock:
 440         ftrace_hash_unlock(flags);
 441  out:
 442         per_cpu(ftrace_shutdown_disable_cpu, cpu)--;
 443
 444         /* prevent recursion with scheduler */
 445         if (resched)
 446                 preempt_enable_no_resched_notrace();
 447         else
 448                 preempt_enable_notrace();
 449 }
 450
 451 #define FTRACE_ADDR ((long)(ftrace_caller))
 452
 453 static int
 454 __ftrace_replace_code(struct dyn_ftrace *rec,
 455                       unsigned char *old, unsigned char *new, int enable)
 456 {
 457         unsigned long ip, fl;
 458
 459         ip = rec->ip;
 460
 461         if (ftrace_filtered && enable) {
 462                 /*
 463                  * If filtering is on:
 464                  *
 465                  * If this record is set to be filtered and
 466                  * is enabled then do nothing.
 467                  *
 468                  * If this record is set to be filtered and
 469                  * it is not enabled, enable it.
 470                  *
 471                  * If this record is not set to be filtered
 472                  * and it is not enabled do nothing.
 473                  *
 474                  * If this record is set not to trace then
 475                  * do nothing.
 476                  *
 477                  * If this record is set not to trace and
 478                  * it is enabled then disable it.
 479                  *
 480                  * If this record is not set to be filtered and
 481                  * it is enabled, disable it.
 482                  */
 483
 484                 fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_NOTRACE |
 485                                    FTRACE_FL_ENABLED);
 486
 487                 if ((fl ==  (FTRACE_FL_FILTER | FTRACE_FL_ENABLED)) ||
 488                     (fl ==  (FTRACE_FL_FILTER | FTRACE_FL_NOTRACE)) ||
 489                     !fl || (fl == FTRACE_FL_NOTRACE))
 490                         return 0;
 491
 492                 /*
 493                  * If it is enabled disable it,
 494                  * otherwise enable it!
 495                  */
 496                 if (fl & FTRACE_FL_ENABLED) {
 497                         /* swap new and old */
 498                         new = old;
 499                         old = ftrace_call_replace(ip, FTRACE_ADDR);
 500                         rec->flags &= ~FTRACE_FL_ENABLED;
 501                 } else {
 502                         new = ftrace_call_replace(ip, FTRACE_ADDR);
 503                         rec->flags |= FTRACE_FL_ENABLED;
 504                 }
 505         } else {
 506
 507                 if (enable) {
 508                         /*
 509                          * If this record is set not to trace and is
 510                          * not enabled, do nothing.
 511                          */
 512                         fl = rec->flags & (FTRACE_FL_NOTRACE | FTRACE_FL_ENABLED);
 513                         if (fl == FTRACE_FL_NOTRACE)
 514                                 return 0;
 515
 516                         new = ftrace_call_replace(ip, FTRACE_ADDR);
 517                 } else
 518                         old = ftrace_call_replace(ip, FTRACE_ADDR);
 519
 520                 if (enable) {
 521                         if (rec->flags & FTRACE_FL_ENABLED)
 522                                 return 0;
 523                         rec->flags |= FTRACE_FL_ENABLED;
 524                 } else {
 525                         if (!(rec->flags & FTRACE_FL_ENABLED))
 526                                 return 0;
 527                         rec->flags &= ~FTRACE_FL_ENABLED;
 528                 }
 529         }
 530
 531         return ftrace_modify_code(ip, old, new);
 532 }
 533
 534 static void ftrace_replace_code(int enable)
 535 {
 536         int i, failed;
 537         unsigned char *new = NULL, *old = NULL;
 538         struct dyn_ftrace *rec;
 539         struct ftrace_page *pg;
 540
 541         if (enable)
 542                 old = ftrace_nop_replace();
 543         else
 544                 new = ftrace_nop_replace();
 545
 546         for (pg = ftrace_pages_start; pg; pg = pg->next) {
 547                 for (i = 0; i < pg->index; i++) {
 548                         rec = &pg->records[i];
 549
 550                         /* don't modify code that has already faulted */
 551                         if (rec->flags & FTRACE_FL_FAILED)
 552                                 continue;
 553
 554                         /* ignore updates to this record's mcount site */
 555                         if (get_kprobe((void *)rec->ip)) {
 556                                 freeze_record(rec);
 557                                 continue;
 558                         } else {
 559                                 unfreeze_record(rec);
 560                         }
 561
 562                         failed = __ftrace_replace_code(rec, old, new, enable);
 563                         if (failed && (rec->flags & FTRACE_FL_CONVERTED)) {
 564                                 rec->flags |= FTRACE_FL_FAILED;
 565                                 if ((system_state == SYSTEM_BOOTING) ||
 566                                     !core_kernel_text(rec->ip)) {
 567                                         ftrace_del_hash(rec);
 568                                         ftrace_free_rec(rec);
 569                                 }
 570                         }
 571                 }
 572         }
 573 }
 574
 575 static void ftrace_shutdown_replenish(void)
 576 {
 577         if (ftrace_pages->next)
 578                 return;
 579
 580         /* allocate another page */
 581         ftrace_pages->next = (void *)get_zeroed_page(GFP_KERNEL);
 582 }
 583
 584 static void print_ip_ins(const char *fmt, unsigned char *p)
 585 {
 586         int i;
 587
 588         printk(KERN_CONT "%s", fmt);
 589
 590         for (i = 0; i < MCOUNT_INSN_SIZE; i++)
 591                 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
 592 }
 593
 594 static int
 595 ftrace_code_disable(struct dyn_ftrace *rec)
 596 {
 597         unsigned long ip;
 598         unsigned char *nop, *call;
 599         int ret;
 600
 601         ip = rec->ip;
 602
 603         nop = ftrace_nop_replace();
 604         call = ftrace_call_replace(ip, mcount_addr);
 605
 606         ret = ftrace_modify_code(ip, call, nop);
 607         if (ret) {
 608                 switch (ret) {
 609                 case -EFAULT:
 610                         WARN_ON_ONCE(1);
 611                         pr_info("ftrace faulted on modifying ");
 612                         print_ip_sym(ip);
 613                         break;
 614                 case -EINVAL:
 615                         WARN_ON_ONCE(1);
 616                         pr_info("ftrace failed to modify ");
 617                         print_ip_sym(ip);
 618                         print_ip_ins(" expected: ", call);
 619                         print_ip_ins(" actual: ", (unsigned char *)ip);
 620                         print_ip_ins(" replace: ", nop);
 621                         printk(KERN_CONT "\n");
 622                         break;
 623                 case -EPERM:
 624                         WARN_ON_ONCE(1);
 625                         pr_info("ftrace faulted on writing ");
 626                         print_ip_sym(ip);
 627                         break;
 628                 default:
 629                         WARN_ON_ONCE(1);
 630                         pr_info("ftrace faulted on unknown error ");
 631                         print_ip_sym(ip);
 632                 }
 633
 634                 rec->flags |= FTRACE_FL_FAILED;
 635                 return 0;
 636         }
 637         return 1;
 638 }
 639
 640 static int __ftrace_update_code(void *ignore);
 641
 642 static int __ftrace_modify_code(void *data)
 643 {
 644         unsigned long addr;
 645         int *command = data;
 646
 647         if (*command & FTRACE_ENABLE_CALLS) {
 648                 /*
 649                  * Update any recorded ips now that we have the
 650                  * machine stopped
 651                  */
 652                 __ftrace_update_code(NULL);
 653                 ftrace_replace_code(1);
 654                 tracing_on = 1;
 655         } else if (*command & FTRACE_DISABLE_CALLS) {
 656                 ftrace_replace_code(0);
 657                 tracing_on = 0;
 658         }
 659
 660         if (*command & FTRACE_UPDATE_TRACE_FUNC)
 661                 ftrace_update_ftrace_func(ftrace_trace_function);
 662
 663         if (*command & FTRACE_ENABLE_MCOUNT) {
 664                 addr = (unsigned long)ftrace_record_ip;
 665                 ftrace_mcount_set(&addr);
 666         } else if (*command & FTRACE_DISABLE_MCOUNT) {
 667                 addr = (unsigned long)ftrace_stub;
 668                 ftrace_mcount_set(&addr);
 669         }
 670
 671         return 0;
 672 }
 673
 674 static void ftrace_run_update_code(int command)
 675 {
 676         stop_machine(__ftrace_modify_code, &command, NULL);
 677 }
 678
 679 void ftrace_disable_daemon(void)
 680 {
 681         /* Stop the daemon from calling kstop_machine */
 682         mutex_lock(&ftraced_lock);
 683         ftraced_stop = 1;
 684         mutex_unlock(&ftraced_lock);
 685
 686         ftrace_force_update();
 687 }
 688
 689 void ftrace_enable_daemon(void)
 690 {
 691         mutex_lock(&ftraced_lock);
 692         ftraced_stop = 0;
 693         mutex_unlock(&ftraced_lock);
 694
 695         ftrace_force_update();
 696 }
 697
 698 static ftrace_func_t saved_ftrace_func;
 699
 700 static void ftrace_startup(void)
 701 {
 702         int command = 0;
 703
 704         if (unlikely(ftrace_disabled))
 705                 return;
 706
 707         mutex_lock(&ftraced_lock);
 708         ftraced_suspend++;
 709         if (ftraced_suspend == 1)
 710                 command |= FTRACE_ENABLE_CALLS;
 711
 712         if (saved_ftrace_func != ftrace_trace_function) {
 713                 saved_ftrace_func = ftrace_trace_function;
 714                 command |= FTRACE_UPDATE_TRACE_FUNC;
 715         }
 716
 717         if (!command || !ftrace_enabled)
 718                 goto out;
 719
 720         ftrace_run_update_code(command);
 721  out:
 722         mutex_unlock(&ftraced_lock);
 723 }
 724
 725 static void ftrace_shutdown(void)
 726 {
 727         int command = 0;
 728
 729         if (unlikely(ftrace_disabled))
 730                 return;
 731
 732         mutex_lock(&ftraced_lock);
 733         ftraced_suspend--;
 734         if (!ftraced_suspend)
 735                 command |= FTRACE_DISABLE_CALLS;
 736
 737         if (saved_ftrace_func != ftrace_trace_function) {
 738                 saved_ftrace_func = ftrace_trace_function;
 739                 command |= FTRACE_UPDATE_TRACE_FUNC;
 740         }
 741
 742         if (!command || !ftrace_enabled)
 743                 goto out;
 744
 745         ftrace_run_update_code(command);
 746  out:
 747         mutex_unlock(&ftraced_lock);
 748 }
 749
 750 static void ftrace_startup_sysctl(void)
 751 {
 752         int command = FTRACE_ENABLE_MCOUNT;
 753
 754         if (unlikely(ftrace_disabled))
 755                 return;
 756
 757         mutex_lock(&ftraced_lock);
 758         /* Force update next time */
 759         saved_ftrace_func = NULL;
 760         /* ftraced_suspend is true if we want ftrace running */
 761         if (ftraced_suspend)
 762                 command |= FTRACE_ENABLE_CALLS;
 763
 764         ftrace_run_update_code(command);
 765         mutex_unlock(&ftraced_lock);
 766 }
 767
 768 static void ftrace_shutdown_sysctl(void)
 769 {
 770         int command = FTRACE_DISABLE_MCOUNT;
 771
 772         if (unlikely(ftrace_disabled))
 773                 return;
 774
 775         mutex_lock(&ftraced_lock);
 776         /* ftraced_suspend is true if ftrace is running */
 777         if (ftraced_suspend)
 778                 command |= FTRACE_DISABLE_CALLS;
 779
 780         ftrace_run_update_code(command);
 781         mutex_unlock(&ftraced_lock);
 782 }
 783
 784 static cycle_t          ftrace_update_time;
 785 static unsigned long    ftrace_update_cnt;
 786 unsigned long           ftrace_update_tot_cnt;
 787
 788 static int __ftrace_update_code(void *ignore)
 789 {
 790         int i, save_ftrace_enabled;
 791         cycle_t start, stop;
 792         struct dyn_ftrace *p;
 793         struct hlist_node *t, *n;
 794         struct hlist_head *head, temp_list;
 795
 796         /* Don't be recording funcs now */
 797         ftrace_record_suspend++;
 798         save_ftrace_enabled = ftrace_enabled;
 799         ftrace_enabled = 0;
 800
 801         start = ftrace_now(raw_smp_processor_id());
 802         ftrace_update_cnt = 0;
 803
 804         /* No locks needed, the machine is stopped! */
 805         for (i = 0; i < FTRACE_HASHSIZE; i++) {
 806                 INIT_HLIST_HEAD(&temp_list);
 807                 head = &ftrace_hash[i];
 808
 809                 /* all CPUS are stopped, we are safe to modify code */
 810                 hlist_for_each_entry_safe(p, t, n, head, node) {
 811                         /* Skip over failed records which have not been
 812                          * freed. */
 813                         if (p->flags & FTRACE_FL_FAILED)
 814                                 continue;
 815
 816                         /* Unconverted records are always at the head of the
 817                          * hash bucket. Once we encounter a converted record,
 818                          * simply skip over to the next bucket. Saves ftraced
 819                          * some processor cycles (ftrace does its bid for
 820                          * global warming :-p ). */
 821                         if (p->flags & (FTRACE_FL_CONVERTED))
 822                                 break;
 823
 824                         /* Ignore updates to this record's mcount site.
 825                          * Reintroduce this record at the head of this
 826                          * bucket to attempt to "convert" it again if
 827                          * the kprobe on it is unregistered before the
 828                          * next run. */
 829                         if (get_kprobe((void *)p->ip)) {
 830                                 ftrace_del_hash(p);
 831                                 INIT_HLIST_NODE(&p->node);
 832                                 hlist_add_head(&p->node, &temp_list);
 833                                 freeze_record(p);
 834                                 continue;
 835                         } else {
 836                                 unfreeze_record(p);
 837                         }
 838
 839                         /* convert record (i.e, patch mcount-call with NOP) */
 840                         if (ftrace_code_disable(p)) {
 841                                 p->flags |= FTRACE_FL_CONVERTED;
 842                                 ftrace_update_cnt++;
 843                         } else {
 844                                 if ((system_state == SYSTEM_BOOTING) ||
 845                                     !core_kernel_text(p->ip)) {
 846                                         ftrace_del_hash(p);
 847                                         ftrace_free_rec(p);
 848                                 }
 849                         }
 850                 }
 851
 852                 hlist_for_each_entry_safe(p, t, n, &temp_list, node) {
 853                         hlist_del(&p->node);
 854                         INIT_HLIST_NODE(&p->node);
 855                         hlist_add_head(&p->node, head);
 856                 }
 857         }
 858
 859         stop = ftrace_now(raw_smp_processor_id());
 860         ftrace_update_time = stop - start;
 861         ftrace_update_tot_cnt += ftrace_update_cnt;
 862         ftraced_trigger = 0;
 863
 864         ftrace_enabled = save_ftrace_enabled;
 865         ftrace_record_suspend--;
 866
 867         return 0;
 868 }
 869
 870 static int ftrace_update_code(void)
 871 {
 872         if (unlikely(ftrace_disabled) ||
 873             !ftrace_enabled || !ftraced_trigger)
 874                 return 0;
 875
 876         stop_machine(__ftrace_update_code, NULL, NULL);
 877
 878         return 1;
 879 }
 880
 881 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
 882 {
 883         struct ftrace_page *pg;
 884         int cnt;
 885         int i;
 886
 887         /* allocate a few pages */
 888         ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
 889         if (!ftrace_pages_start)
 890                 return -1;
 891
 892         /*
 893          * Allocate a few more pages.
 894          *
 895          * TODO: have some parser search vmlinux before
 896          *   final linking to find all calls to ftrace.
 897          *   Then we can:
 898          *    a) know how many pages to allocate.
 899          *     and/or
 900          *    b) set up the table then.
 901          *
 902          *  The dynamic code is still necessary for
 903          *  modules.
 904          */
 905
 906         pg = ftrace_pages = ftrace_pages_start;
 907
 908         cnt = num_to_init / ENTRIES_PER_PAGE;
 909         pr_info("ftrace: allocating %ld hash entries in %d pages\n",
 910                 num_to_init, cnt);
 911
 912         for (i = 0; i < cnt; i++) {
 913                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
 914
 915                 /* If we fail, we'll try later anyway */
 916                 if (!pg->next)
 917                         break;
 918
 919                 pg = pg->next;
 920         }
 921
 922         return 0;
 923 }
 924
 925 enum {
 926         FTRACE_ITER_FILTER      = (1 << 0),
 927         FTRACE_ITER_CONT        = (1 << 1),
 928         FTRACE_ITER_NOTRACE     = (1 << 2),
 929         FTRACE_ITER_FAILURES    = (1 << 3),
 930 };
 931
 932 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
 933
 934 struct ftrace_iterator {
 935         loff_t                  pos;
 936         struct ftrace_page      *pg;
 937         unsigned                idx;
 938         unsigned                flags;
 939         unsigned char           buffer[FTRACE_BUFF_MAX+1];
 940         unsigned                buffer_idx;
 941         unsigned                filtered;
 942 };
 943
 944 static void *
 945 t_next(struct seq_file *m, void *v, loff_t *pos)
 946 {
 947         struct ftrace_iterator *iter = m->private;
 948         struct dyn_ftrace *rec = NULL;
 949
 950         (*pos)++;
 951
 952         /* should not be called from interrupt context */
 953         spin_lock(&ftrace_lock);
 954  retry:
 955         if (iter->idx >= iter->pg->index) {
 956                 if (iter->pg->next) {
 957                         iter->pg = iter->pg->next;
 958                         iter->idx = 0;
 959                         goto retry;
 960                 }
 961         } else {
 962                 rec = &iter->pg->records[iter->idx++];
 963                 if ((rec->flags & FTRACE_FL_FREE) ||
 964
 965                     (!(iter->flags & FTRACE_ITER_FAILURES) &&
 966                      (rec->flags & FTRACE_FL_FAILED)) ||
 967
 968                     ((iter->flags & FTRACE_ITER_FAILURES) &&
 969                      !(rec->flags & FTRACE_FL_FAILED)) ||
 970
 971                     ((iter->flags & FTRACE_ITER_NOTRACE) &&
 972                      !(rec->flags & FTRACE_FL_NOTRACE))) {
 973                         rec = NULL;
 974                         goto retry;
 975                 }
 976         }
 977         spin_unlock(&ftrace_lock);
 978
 979         iter->pos = *pos;
 980
 981         return rec;
 982 }
 983
 984 static void *t_start(struct seq_file *m, loff_t *pos)
 985 {
 986         struct ftrace_iterator *iter = m->private;
 987         void *p = NULL;
 988         loff_t l = -1;
 989
 990         if (*pos != iter->pos) {
 991                 for (p = t_next(m, p, &l); p && l < *pos; p = t_next(m, p, &l))
 992                         ;
 993         } else {
 994                 l = *pos;
 995                 p = t_next(m, p, &l);
 996         }
 997
 998         return p;
 999 }
1000
1001 static void t_stop(struct seq_file *m, void *p)
1002 {
1003 }
1004
1005 static int t_show(struct seq_file *m, void *v)
1006 {
1007         struct dyn_ftrace *rec = v;
1008         char str[KSYM_SYMBOL_LEN];
1009
1010         if (!rec)
1011                 return 0;
1012
1013         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1014
1015         seq_printf(m, "%s\n", str);
1016
1017         return 0;
1018 }
1019
1020 static struct seq_operations show_ftrace_seq_ops = {
1021         .start = t_start,
1022         .next = t_next,
1023         .stop = t_stop,
1024         .show = t_show,
1025 };
1026
1027 static int
1028 ftrace_avail_open(struct inode *inode, struct file *file)
1029 {
1030         struct ftrace_iterator *iter;
1031         int ret;
1032
1033         if (unlikely(ftrace_disabled))
1034                 return -ENODEV;
1035
1036         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1037         if (!iter)
1038                 return -ENOMEM;
1039
1040         iter->pg = ftrace_pages_start;
1041         iter->pos = -1;
1042
1043         ret = seq_open(file, &show_ftrace_seq_ops);
1044         if (!ret) {
1045                 struct seq_file *m = file->private_data;
1046
1047                 m->private = iter;
1048         } else {
1049                 kfree(iter);
1050         }
1051
1052         return ret;
1053 }
1054
1055 int ftrace_avail_release(struct inode *inode, struct file *file)
1056 {
1057         struct seq_file *m = (struct seq_file *)file->private_data;
1058         struct ftrace_iterator *iter = m->private;
1059
1060         seq_release(inode, file);
1061         kfree(iter);
1062
1063         return 0;
1064 }
1065
1066 static int
1067 ftrace_failures_open(struct inode *inode, struct file *file)
1068 {
1069         int ret;
1070         struct seq_file *m;
1071         struct ftrace_iterator *iter;
1072
1073         ret = ftrace_avail_open(inode, file);
1074         if (!ret) {
1075                 m = (struct seq_file *)file->private_data;
1076                 iter = (struct ftrace_iterator *)m->private;
1077                 iter->flags = FTRACE_ITER_FAILURES;
1078         }
1079
1080         return ret;
1081 }
1082
1083
1084 static void ftrace_filter_reset(int enable)
1085 {
1086         struct ftrace_page *pg;
1087         struct dyn_ftrace *rec;
1088         unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1089         unsigned i;
1090
1091         /* should not be called from interrupt context */
1092         spin_lock(&ftrace_lock);
1093         if (enable)
1094                 ftrace_filtered = 0;
1095         pg = ftrace_pages_start;
1096         while (pg) {
1097                 for (i = 0; i < pg->index; i++) {
1098                         rec = &pg->records[i];
1099                         if (rec->flags & FTRACE_FL_FAILED)
1100                                 continue;
1101                         rec->flags &= ~type;
1102                 }
1103                 pg = pg->next;
1104         }
1105         spin_unlock(&ftrace_lock);
1106 }
1107
1108 static int
1109 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
1110 {
1111         struct ftrace_iterator *iter;
1112         int ret = 0;
1113
1114         if (unlikely(ftrace_disabled))
1115                 return -ENODEV;
1116
1117         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1118         if (!iter)
1119                 return -ENOMEM;
1120
1121         mutex_lock(&ftrace_regex_lock);
1122         if ((file->f_mode & FMODE_WRITE) &&
1123             !(file->f_flags & O_APPEND))
1124                 ftrace_filter_reset(enable);
1125
1126         if (file->f_mode & FMODE_READ) {
1127                 iter->pg = ftrace_pages_start;
1128                 iter->pos = -1;
1129                 iter->flags = enable ? FTRACE_ITER_FILTER :
1130                         FTRACE_ITER_NOTRACE;
1131
1132                 ret = seq_open(file, &show_ftrace_seq_ops);
1133                 if (!ret) {
1134                         struct seq_file *m = file->private_data;
1135                         m->private = iter;
1136                 } else
1137                         kfree(iter);
1138         } else
1139                 file->private_data = iter;
1140         mutex_unlock(&ftrace_regex_lock);
1141
1142         return ret;
1143 }
1144
1145 static int
1146 ftrace_filter_open(struct inode *inode, struct file *file)
1147 {
1148         return ftrace_regex_open(inode, file, 1);
1149 }
1150
1151 static int
1152 ftrace_notrace_open(struct inode *inode, struct file *file)
1153 {
1154         return ftrace_regex_open(inode, file, 0);
1155 }
1156
1157 static ssize_t
1158 ftrace_regex_read(struct file *file, char __user *ubuf,
1159                        size_t cnt, loff_t *ppos)
1160 {
1161         if (file->f_mode & FMODE_READ)
1162                 return seq_read(file, ubuf, cnt, ppos);
1163         else
1164                 return -EPERM;
1165 }
1166
1167 static loff_t
1168 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1169 {
1170         loff_t ret;
1171
1172         if (file->f_mode & FMODE_READ)
1173                 ret = seq_lseek(file, offset, origin);
1174         else
1175                 file->f_pos = ret = 1;
1176
1177         return ret;
1178 }
1179
1180 enum {
1181         MATCH_FULL,
1182         MATCH_FRONT_ONLY,
1183         MATCH_MIDDLE_ONLY,
1184         MATCH_END_ONLY,
1185 };
1186
1187 static void
1188 ftrace_match(unsigned char *buff, int len, int enable)
1189 {
1190         char str[KSYM_SYMBOL_LEN];
1191         char *search = NULL;
1192         struct ftrace_page *pg;
1193         struct dyn_ftrace *rec;
1194         int type = MATCH_FULL;
1195         unsigned long flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1196         unsigned i, match = 0, search_len = 0;
1197
1198         for (i = 0; i < len; i++) {
1199                 if (buff[i] == '*') {
1200                         if (!i) {
1201                                 search = buff + i + 1;
1202                                 type = MATCH_END_ONLY;
1203                                 search_len = len - (i + 1);
1204                         } else {
1205                                 if (type == MATCH_END_ONLY) {
1206                                         type = MATCH_MIDDLE_ONLY;
1207                                 } else {
1208                                         match = i;
1209                                         type = MATCH_FRONT_ONLY;
1210                                 }
1211                                 buff[i] = 0;
1212                                 break;
1213                         }
1214                 }
1215         }
1216
1217         /* should not be called from interrupt context */
1218         spin_lock(&ftrace_lock);
1219         if (enable)
1220                 ftrace_filtered = 1;
1221         pg = ftrace_pages_start;
1222         while (pg) {
1223                 for (i = 0; i < pg->index; i++) {
1224                         int matched = 0;
1225                         char *ptr;
1226
1227                         rec = &pg->records[i];
1228                         if (rec->flags & FTRACE_FL_FAILED)
1229                                 continue;
1230                         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1231                         switch (type) {
1232                         case MATCH_FULL:
1233                                 if (strcmp(str, buff) == 0)
1234                                         matched = 1;
1235                                 break;
1236                         case MATCH_FRONT_ONLY:
1237                                 if (memcmp(str, buff, match) == 0)
1238                                         matched = 1;
1239                                 break;
1240                         case MATCH_MIDDLE_ONLY:
1241                                 if (strstr(str, search))
1242                                         matched = 1;
1243                                 break;
1244                         case MATCH_END_ONLY:
1245                                 ptr = strstr(str, search);
1246                                 if (ptr && (ptr[search_len] == 0))
1247                                         matched = 1;
1248                                 break;
1249                         }
1250                         if (matched)
1251                                 rec->flags |= flag;
1252                 }
1253                 pg = pg->next;
1254         }
1255         spin_unlock(&ftrace_lock);
1256 }
1257
1258 static ssize_t
1259 ftrace_regex_write(struct file *file, const char __user *ubuf,
1260                    size_t cnt, loff_t *ppos, int enable)
1261 {
1262         struct ftrace_iterator *iter;
1263         char ch;
1264         size_t read = 0;
1265         ssize_t ret;
1266
1267         if (!cnt || cnt < 0)
1268                 return 0;
1269
1270         mutex_lock(&ftrace_regex_lock);
1271
1272         if (file->f_mode & FMODE_READ) {
1273                 struct seq_file *m = file->private_data;
1274                 iter = m->private;
1275         } else
1276                 iter = file->private_data;
1277
1278         if (!*ppos) {
1279                 iter->flags &= ~FTRACE_ITER_CONT;
1280                 iter->buffer_idx = 0;
1281         }
1282
1283         ret = get_user(ch, ubuf++);
1284         if (ret)
1285                 goto out;
1286         read++;
1287         cnt--;
1288
1289         if (!(iter->flags & ~FTRACE_ITER_CONT)) {
1290                 /* skip white space */
1291                 while (cnt && isspace(ch)) {
1292                         ret = get_user(ch, ubuf++);
1293                         if (ret)
1294                                 goto out;
1295                         read++;
1296                         cnt--;
1297                 }
1298
1299                 if (isspace(ch)) {
1300                         file->f_pos += read;
1301                         ret = read;
1302                         goto out;
1303                 }
1304
1305                 iter->buffer_idx = 0;
1306         }
1307
1308         while (cnt && !isspace(ch)) {
1309                 if (iter->buffer_idx < FTRACE_BUFF_MAX)
1310                         iter->buffer[iter->buffer_idx++] = ch;
1311                 else {
1312                         ret = -EINVAL;
1313                         goto out;
1314                 }
1315                 ret = get_user(ch, ubuf++);
1316                 if (ret)
1317                         goto out;
1318                 read++;
1319                 cnt--;
1320         }
1321
1322         if (isspace(ch)) {
1323                 iter->filtered++;
1324                 iter->buffer[iter->buffer_idx] = 0;
1325                 ftrace_match(iter->buffer, iter->buffer_idx, enable);
1326                 iter->buffer_idx = 0;
1327         } else
1328                 iter->flags |= FTRACE_ITER_CONT;
1329
1330
1331         file->f_pos += read;
1332
1333         ret = read;
1334  out:
1335         mutex_unlock(&ftrace_regex_lock);
1336
1337         return ret;
1338 }
1339
1340 static ssize_t
1341 ftrace_filter_write(struct file *file, const char __user *ubuf,
1342                     size_t cnt, loff_t *ppos)
1343 {
1344         return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
1345 }
1346
1347 static ssize_t
1348 ftrace_notrace_write(struct file *file, const char __user *ubuf,
1349                      size_t cnt, loff_t *ppos)
1350 {
1351         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
1352 }
1353
1354 static void
1355 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
1356 {
1357         if (unlikely(ftrace_disabled))
1358                 return;
1359
1360         mutex_lock(&ftrace_regex_lock);
1361         if (reset)
1362                 ftrace_filter_reset(enable);
1363         if (buf)
1364                 ftrace_match(buf, len, enable);
1365         mutex_unlock(&ftrace_regex_lock);
1366 }
1367
1368 /**
1369  * ftrace_set_filter - set a function to filter on in ftrace
1370  * @buf - the string that holds the function filter text.
1371  * @len - the length of the string.
1372  * @reset - non zero to reset all filters before applying this filter.
1373  *
1374  * Filters denote which functions should be enabled when tracing is enabled.
1375  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
1376  */
1377 void ftrace_set_filter(unsigned char *buf, int len, int reset)
1378 {
1379         ftrace_set_regex(buf, len, reset, 1);
1380 }
1381
1382 /**
1383  * ftrace_set_notrace - set a function to not trace in ftrace
1384  * @buf - the string that holds the function notrace text.
1385  * @len - the length of the string.
1386  * @reset - non zero to reset all filters before applying this filter.
1387  *
1388  * Notrace Filters denote which functions should not be enabled when tracing
1389  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
1390  * for tracing.
1391  */
1392 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
1393 {
1394         ftrace_set_regex(buf, len, reset, 0);
1395 }
1396
1397 static int
1398 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
1399 {
1400         struct seq_file *m = (struct seq_file *)file->private_data;
1401         struct ftrace_iterator *iter;
1402
1403         mutex_lock(&ftrace_regex_lock);
1404         if (file->f_mode & FMODE_READ) {
1405                 iter = m->private;
1406
1407                 seq_release(inode, file);
1408         } else
1409                 iter = file->private_data;
1410
1411         if (iter->buffer_idx) {
1412                 iter->filtered++;
1413                 iter->buffer[iter->buffer_idx] = 0;
1414                 ftrace_match(iter->buffer, iter->buffer_idx, enable);
1415         }
1416
1417         mutex_lock(&ftrace_sysctl_lock);
1418         mutex_lock(&ftraced_lock);
1419         if (iter->filtered && ftraced_suspend && ftrace_enabled)
1420                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
1421         mutex_unlock(&ftraced_lock);
1422         mutex_unlock(&ftrace_sysctl_lock);
1423
1424         kfree(iter);
1425         mutex_unlock(&ftrace_regex_lock);
1426         return 0;
1427 }
1428
1429 static int
1430 ftrace_filter_release(struct inode *inode, struct file *file)
1431 {
1432         return ftrace_regex_release(inode, file, 1);
1433 }
1434
1435 static int
1436 ftrace_notrace_release(struct inode *inode, struct file *file)
1437 {
1438         return ftrace_regex_release(inode, file, 0);
1439 }
1440
1441 static ssize_t
1442 ftraced_read(struct file *filp, char __user *ubuf,
1443                      size_t cnt, loff_t *ppos)
1444 {
1445         /* don't worry about races */
1446         char *buf = ftraced_stop ? "disabled\n" : "enabled\n";
1447         int r = strlen(buf);
1448
1449         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1450 }
1451
1452 static ssize_t
1453 ftraced_write(struct file *filp, const char __user *ubuf,
1454                       size_t cnt, loff_t *ppos)
1455 {
1456         char buf[64];
1457         long val;
1458         int ret;
1459
1460         if (cnt >= sizeof(buf))
1461                 return -EINVAL;
1462
1463         if (copy_from_user(&buf, ubuf, cnt))
1464                 return -EFAULT;
1465
1466         if (strncmp(buf, "enable", 6) == 0)
1467                 val = 1;
1468         else if (strncmp(buf, "disable", 7) == 0)
1469                 val = 0;
1470         else {
1471                 buf[cnt] = 0;
1472
1473                 ret = strict_strtoul(buf, 10, &val);
1474                 if (ret < 0)
1475                         return ret;
1476
1477                 val = !!val;
1478         }
1479
1480         if (val)
1481                 ftrace_enable_daemon();
1482         else
1483                 ftrace_disable_daemon();
1484
1485         filp->f_pos += cnt;
1486
1487         return cnt;
1488 }
1489
1490 static struct file_operations ftrace_avail_fops = {
1491         .open = ftrace_avail_open,
1492         .read = seq_read,
1493         .llseek = seq_lseek,
1494         .release = ftrace_avail_release,
1495 };
1496
1497 static struct file_operations ftrace_failures_fops = {
1498         .open = ftrace_failures_open,
1499         .read = seq_read,
1500         .llseek = seq_lseek,
1501         .release = ftrace_avail_release,
1502 };
1503
1504 static struct file_operations ftrace_filter_fops = {
1505         .open = ftrace_filter_open,
1506         .read = ftrace_regex_read,
1507         .write = ftrace_filter_write,
1508         .llseek = ftrace_regex_lseek,
1509         .release = ftrace_filter_release,
1510 };
1511
1512 static struct file_operations ftrace_notrace_fops = {
1513         .open = ftrace_notrace_open,
1514         .read = ftrace_regex_read,
1515         .write = ftrace_notrace_write,
1516         .llseek = ftrace_regex_lseek,
1517         .release = ftrace_notrace_release,
1518 };
1519
1520 static struct file_operations ftraced_fops = {
1521         .open = tracing_open_generic,
1522         .read = ftraced_read,
1523         .write = ftraced_write,
1524 };
1525
1526 /**
1527  * ftrace_force_update - force an update to all recording ftrace functions
1528  */
1529 int ftrace_force_update(void)
1530 {
1531         int ret = 0;
1532
1533         if (unlikely(ftrace_disabled))
1534                 return -ENODEV;
1535
1536         mutex_lock(&ftrace_sysctl_lock);
1537         mutex_lock(&ftraced_lock);
1538
1539         /*
1540          * If ftraced_trigger is not set, then there is nothing
1541          * to update.
1542          */
1543         if (ftraced_trigger && !ftrace_update_code())
1544                 ret = -EBUSY;
1545
1546         mutex_unlock(&ftraced_lock);
1547         mutex_unlock(&ftrace_sysctl_lock);
1548
1549         return ret;
1550 }
1551
1552 static __init int ftrace_init_debugfs(void)
1553 {
1554         struct dentry *d_tracer;
1555         struct dentry *entry;
1556
1557         d_tracer = tracing_init_dentry();
1558
1559         entry = debugfs_create_file("available_filter_functions", 0444,
1560                                     d_tracer, NULL, &ftrace_avail_fops);
1561         if (!entry)
1562                 pr_warning("Could not create debugfs "
1563                            "'available_filter_functions' entry\n");
1564
1565         entry = debugfs_create_file("failures", 0444,
1566                                     d_tracer, NULL, &ftrace_failures_fops);
1567         if (!entry)
1568                 pr_warning("Could not create debugfs 'failures' entry\n");
1569
1570         entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer,
1571                                     NULL, &ftrace_filter_fops);
1572         if (!entry)
1573                 pr_warning("Could not create debugfs "
1574                            "'set_ftrace_filter' entry\n");
1575
1576         entry = debugfs_create_file("set_ftrace_notrace", 0644, d_tracer,
1577                                     NULL, &ftrace_notrace_fops);
1578         if (!entry)
1579                 pr_warning("Could not create debugfs "
1580                            "'set_ftrace_notrace' entry\n");
1581
1582         entry = debugfs_create_file("ftraced_enabled", 0644, d_tracer,
1583                                     NULL, &ftraced_fops);
1584         if (!entry)
1585                 pr_warning("Could not create debugfs "
1586                            "'ftraced_enabled' entry\n");
1587         return 0;
1588 }
1589
1590 fs_initcall(ftrace_init_debugfs);
1591
1592 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
1593 static int ftrace_convert_nops(unsigned long *start,
1594                                unsigned long *end)
1595 {
1596         unsigned long *p;
1597         unsigned long addr;
1598         unsigned long flags;
1599
1600         p = start;
1601         while (p < end) {
1602                 addr = ftrace_call_adjust(*p++);
1603                 /* should not be called from interrupt context */
1604                 spin_lock(&ftrace_lock);
1605                 ftrace_record_ip(addr);
1606                 spin_unlock(&ftrace_lock);
1607                 ftrace_shutdown_replenish();
1608         }
1609
1610         /* p is ignored */
1611         local_irq_save(flags);
1612         __ftrace_update_code(p);
1613         local_irq_restore(flags);
1614
1615         return 0;
1616 }
1617
1618 void ftrace_init_module(unsigned long *start, unsigned long *end)
1619 {
1620         if (ftrace_disabled || start == end)
1621                 return;
1622         ftrace_convert_nops(start, end);
1623 }
1624
1625 extern unsigned long __start_mcount_loc[];
1626 extern unsigned long __stop_mcount_loc[];
1627
1628 void __init ftrace_init(void)
1629 {
1630         unsigned long count, addr, flags;
1631         int ret;
1632
1633         /* Keep the ftrace pointer to the stub */
1634         addr = (unsigned long)ftrace_stub;
1635
1636         local_irq_save(flags);
1637         ftrace_dyn_arch_init(&addr);
1638         local_irq_restore(flags);
1639
1640         /* ftrace_dyn_arch_init places the return code in addr */
1641         if (addr)
1642                 goto failed;
1643
1644         count = __stop_mcount_loc - __start_mcount_loc;
1645
1646         ret = ftrace_dyn_table_alloc(count);
1647         if (ret)
1648                 goto failed;
1649
1650         last_ftrace_enabled = ftrace_enabled = 1;
1651
1652         ret = ftrace_convert_nops(__start_mcount_loc,
1653                                   __stop_mcount_loc);
1654
1655         return;
1656  failed:
1657         ftrace_disabled = 1;
1658 }
1659 #else /* CONFIG_FTRACE_MCOUNT_RECORD */
1660
1661 static void ftrace_release_hash(unsigned long start, unsigned long end)
1662 {
1663         struct dyn_ftrace *rec;
1664         struct hlist_node *t, *n;
1665         struct hlist_head *head, temp_list;
1666         unsigned long flags;
1667         int i, cpu;
1668
1669         preempt_disable_notrace();
1670
1671         /* disable incase we call something that calls mcount */
1672         cpu = raw_smp_processor_id();
1673         per_cpu(ftrace_shutdown_disable_cpu, cpu)++;
1674
1675         ftrace_hash_lock(flags);
1676
1677         for (i = 0; i < FTRACE_HASHSIZE; i++) {
1678                 INIT_HLIST_HEAD(&temp_list);
1679                 head = &ftrace_hash[i];
1680
1681                 /* all CPUS are stopped, we are safe to modify code */
1682                 hlist_for_each_entry_safe(rec, t, n, head, node) {
1683                         if (rec->flags & FTRACE_FL_FREE)
1684                                 continue;
1685
1686                         if ((rec->ip >= start) && (rec->ip < end))
1687                                 ftrace_free_rec(rec);
1688                 }
1689         }
1690
1691         ftrace_hash_unlock(flags);
1692
1693         per_cpu(ftrace_shutdown_disable_cpu, cpu)--;
1694         preempt_enable_notrace();
1695
1696 }
1697
1698 static int ftraced(void *ignore)
1699 {
1700         unsigned long usecs;
1701
1702         while (!kthread_should_stop()) {
1703
1704                 set_current_state(TASK_INTERRUPTIBLE);
1705
1706                 /* check once a second */
1707                 schedule_timeout(HZ);
1708
1709                 if (unlikely(ftrace_disabled))
1710                         continue;
1711
1712                 mutex_lock(&ftrace_sysctl_lock);
1713                 mutex_lock(&ftraced_lock);
1714                 if (!ftraced_suspend && !ftraced_stop &&
1715                     ftrace_update_code()) {
1716                         usecs = nsecs_to_usecs(ftrace_update_time);
1717                         if (ftrace_update_tot_cnt > 100000) {
1718                                 ftrace_update_tot_cnt = 0;
1719                                 pr_info("hm, dftrace overflow: %lu change%s"
1720                                         " (%lu total) in %lu usec%s\n",
1721                                         ftrace_update_cnt,
1722                                         ftrace_update_cnt != 1 ? "s" : "",
1723                                         ftrace_update_tot_cnt,
1724                                         usecs, usecs != 1 ? "s" : "");
1725                                 ftrace_disabled = 1;
1726                                 WARN_ON_ONCE(1);
1727                         }
1728                 }
1729                 mutex_unlock(&ftraced_lock);
1730                 mutex_unlock(&ftrace_sysctl_lock);
1731
1732                 ftrace_shutdown_replenish();
1733         }
1734         __set_current_state(TASK_RUNNING);
1735         return 0;
1736 }
1737
1738 static int __init ftrace_dynamic_init(void)
1739 {
1740         struct task_struct *p;
1741         unsigned long addr;
1742         int ret;
1743
1744         addr = (unsigned long)ftrace_record_ip;
1745
1746         stop_machine(ftrace_dyn_arch_init, &addr, NULL);
1747
1748         /* ftrace_dyn_arch_init places the return code in addr */
1749         if (addr) {
1750                 ret = (int)addr;
1751                 goto failed;
1752         }
1753
1754         ret = ftrace_dyn_table_alloc(NR_TO_INIT);
1755         if (ret)
1756                 goto failed;
1757
1758         p = kthread_run(ftraced, NULL, "ftraced");
1759         if (IS_ERR(p)) {
1760                 ret = -1;
1761                 goto failed;
1762         }
1763
1764         last_ftrace_enabled = ftrace_enabled = 1;
1765         ftraced_task = p;
1766
1767         return 0;
1768
1769  failed:
1770         ftrace_disabled = 1;
1771         return ret;
1772 }
1773
1774 core_initcall(ftrace_dynamic_init);
1775 #endif /* CONFIG_FTRACE_MCOUNT_RECORD */
1776
1777 #else
1778 # define ftrace_startup()               do { } while (0)
1779 # define ftrace_shutdown()              do { } while (0)
1780 # define ftrace_startup_sysctl()        do { } while (0)
1781 # define ftrace_shutdown_sysctl()       do { } while (0)
1782 #endif /* CONFIG_DYNAMIC_FTRACE */
1783
1784 /**
1785  * ftrace_kill - kill ftrace
1786  *
1787  * This function should be used by panic code. It stops ftrace
1788  * but in a not so nice way. If you need to simply kill ftrace
1789  * from a non-atomic section, use ftrace_kill.
1790  */
1791 void ftrace_kill(void)
1792 {
1793         ftrace_disabled = 1;
1794         ftrace_enabled = 0;
1795 #ifdef CONFIG_DYNAMIC_FTRACE
1796         ftraced_suspend = -1;
1797 #endif
1798         clear_ftrace_function();
1799 }
1800
1801 /**
1802  * register_ftrace_function - register a function for profiling
1803  * @ops - ops structure that holds the function for profiling.
1804  *
1805  * Register a function to be called by all functions in the
1806  * kernel.
1807  *
1808  * Note: @ops->func and all the functions it calls must be labeled
1809  *       with "notrace", otherwise it will go into a
1810  *       recursive loop.
1811  */
1812 int register_ftrace_function(struct ftrace_ops *ops)
1813 {
1814         int ret;
1815
1816         if (unlikely(ftrace_disabled))
1817                 return -1;
1818
1819         mutex_lock(&ftrace_sysctl_lock);
1820         ret = __register_ftrace_function(ops);
1821         ftrace_startup();
1822         mutex_unlock(&ftrace_sysctl_lock);
1823
1824         return ret;
1825 }
1826
1827 /**
1828  * unregister_ftrace_function - unresgister a function for profiling.
1829  * @ops - ops structure that holds the function to unregister
1830  *
1831  * Unregister a function that was added to be called by ftrace profiling.
1832  */
1833 int unregister_ftrace_function(struct ftrace_ops *ops)
1834 {
1835         int ret;
1836
1837         mutex_lock(&ftrace_sysctl_lock);
1838         ret = __unregister_ftrace_function(ops);
1839         ftrace_shutdown();
1840         mutex_unlock(&ftrace_sysctl_lock);
1841
1842         return ret;
1843 }
1844
1845 int
1846 ftrace_enable_sysctl(struct ctl_table *table, int write,
1847                      struct file *file, void __user *buffer, size_t *lenp,
1848                      loff_t *ppos)
1849 {
1850         int ret;
1851
1852         if (unlikely(ftrace_disabled))
1853                 return -ENODEV;
1854
1855         mutex_lock(&ftrace_sysctl_lock);
1856
1857         ret  = proc_dointvec(table, write, file, buffer, lenp, ppos);
1858
1859         if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
1860                 goto out;
1861
1862         last_ftrace_enabled = ftrace_enabled;
1863
1864         if (ftrace_enabled) {
1865
1866                 ftrace_startup_sysctl();
1867
1868                 /* we are starting ftrace again */
1869                 if (ftrace_list != &ftrace_list_end) {
1870                         if (ftrace_list->next == &ftrace_list_end)
1871                                 ftrace_trace_function = ftrace_list->func;
1872                         else
1873                                 ftrace_trace_function = ftrace_list_func;
1874                 }
1875
1876         } else {
1877                 /* stopping ftrace calls (just send to ftrace_stub) */
1878                 ftrace_trace_function = ftrace_stub;
1879
1880                 ftrace_shutdown_sysctl();
1881         }
1882
1883  out:
1884         mutex_unlock(&ftrace_sysctl_lock);
1885         return ret;
1886 }