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 failed;
 600
 601         ip = rec->ip;
 602
 603         nop = ftrace_nop_replace();
 604         call = ftrace_call_replace(ip, mcount_addr);
 605
 606         failed = ftrace_modify_code(ip, call, nop);
 607         if (failed) {
 608                 switch (failed) {
 609                 case 1:
 610                         WARN_ON_ONCE(1);
 611                         pr_info("ftrace faulted on modifying ");
 612                         print_ip_sym(ip);
 613                         break;
 614                 case 2:
 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                 }
 624
 625                 rec->flags |= FTRACE_FL_FAILED;
 626                 return 0;
 627         }
 628         return 1;
 629 }
 630
 631 static int __ftrace_update_code(void *ignore);
 632
 633 static int __ftrace_modify_code(void *data)
 634 {
 635         unsigned long addr;
 636         int *command = data;
 637
 638         if (*command & FTRACE_ENABLE_CALLS) {
 639                 /*
 640                  * Update any recorded ips now that we have the
 641                  * machine stopped
 642                  */
 643                 __ftrace_update_code(NULL);
 644                 ftrace_replace_code(1);
 645                 tracing_on = 1;
 646         } else if (*command & FTRACE_DISABLE_CALLS) {
 647                 ftrace_replace_code(0);
 648                 tracing_on = 0;
 649         }
 650
 651         if (*command & FTRACE_UPDATE_TRACE_FUNC)
 652                 ftrace_update_ftrace_func(ftrace_trace_function);
 653
 654         if (*command & FTRACE_ENABLE_MCOUNT) {
 655                 addr = (unsigned long)ftrace_record_ip;
 656                 ftrace_mcount_set(&addr);
 657         } else if (*command & FTRACE_DISABLE_MCOUNT) {
 658                 addr = (unsigned long)ftrace_stub;
 659                 ftrace_mcount_set(&addr);
 660         }
 661
 662         return 0;
 663 }
 664
 665 static void ftrace_run_update_code(int command)
 666 {
 667         stop_machine(__ftrace_modify_code, &command, NULL);
 668 }
 669
 670 void ftrace_disable_daemon(void)
 671 {
 672         /* Stop the daemon from calling kstop_machine */
 673         mutex_lock(&ftraced_lock);
 674         ftraced_stop = 1;
 675         mutex_unlock(&ftraced_lock);
 676
 677         ftrace_force_update();
 678 }
 679
 680 void ftrace_enable_daemon(void)
 681 {
 682         mutex_lock(&ftraced_lock);
 683         ftraced_stop = 0;
 684         mutex_unlock(&ftraced_lock);
 685
 686         ftrace_force_update();
 687 }
 688
 689 static ftrace_func_t saved_ftrace_func;
 690
 691 static void ftrace_startup(void)
 692 {
 693         int command = 0;
 694
 695         if (unlikely(ftrace_disabled))
 696                 return;
 697
 698         mutex_lock(&ftraced_lock);
 699         ftraced_suspend++;
 700         if (ftraced_suspend == 1)
 701                 command |= FTRACE_ENABLE_CALLS;
 702
 703         if (saved_ftrace_func != ftrace_trace_function) {
 704                 saved_ftrace_func = ftrace_trace_function;
 705                 command |= FTRACE_UPDATE_TRACE_FUNC;
 706         }
 707
 708         if (!command || !ftrace_enabled)
 709                 goto out;
 710
 711         ftrace_run_update_code(command);
 712  out:
 713         mutex_unlock(&ftraced_lock);
 714 }
 715
 716 static void ftrace_shutdown(void)
 717 {
 718         int command = 0;
 719
 720         if (unlikely(ftrace_disabled))
 721                 return;
 722
 723         mutex_lock(&ftraced_lock);
 724         ftraced_suspend--;
 725         if (!ftraced_suspend)
 726                 command |= FTRACE_DISABLE_CALLS;
 727
 728         if (saved_ftrace_func != ftrace_trace_function) {
 729                 saved_ftrace_func = ftrace_trace_function;
 730                 command |= FTRACE_UPDATE_TRACE_FUNC;
 731         }
 732
 733         if (!command || !ftrace_enabled)
 734                 goto out;
 735
 736         ftrace_run_update_code(command);
 737  out:
 738         mutex_unlock(&ftraced_lock);
 739 }
 740
 741 static void ftrace_startup_sysctl(void)
 742 {
 743         int command = FTRACE_ENABLE_MCOUNT;
 744
 745         if (unlikely(ftrace_disabled))
 746                 return;
 747
 748         mutex_lock(&ftraced_lock);
 749         /* Force update next time */
 750         saved_ftrace_func = NULL;
 751         /* ftraced_suspend is true if we want ftrace running */
 752         if (ftraced_suspend)
 753                 command |= FTRACE_ENABLE_CALLS;
 754
 755         ftrace_run_update_code(command);
 756         mutex_unlock(&ftraced_lock);
 757 }
 758
 759 static void ftrace_shutdown_sysctl(void)
 760 {
 761         int command = FTRACE_DISABLE_MCOUNT;
 762
 763         if (unlikely(ftrace_disabled))
 764                 return;
 765
 766         mutex_lock(&ftraced_lock);
 767         /* ftraced_suspend is true if ftrace is running */
 768         if (ftraced_suspend)
 769                 command |= FTRACE_DISABLE_CALLS;
 770
 771         ftrace_run_update_code(command);
 772         mutex_unlock(&ftraced_lock);
 773 }
 774
 775 static cycle_t          ftrace_update_time;
 776 static unsigned long    ftrace_update_cnt;
 777 unsigned long           ftrace_update_tot_cnt;
 778
 779 static int __ftrace_update_code(void *ignore)
 780 {
 781         int i, save_ftrace_enabled;
 782         cycle_t start, stop;
 783         struct dyn_ftrace *p;
 784         struct hlist_node *t, *n;
 785         struct hlist_head *head, temp_list;
 786
 787         /* Don't be recording funcs now */
 788         ftrace_record_suspend++;
 789         save_ftrace_enabled = ftrace_enabled;
 790         ftrace_enabled = 0;
 791
 792         start = ftrace_now(raw_smp_processor_id());
 793         ftrace_update_cnt = 0;
 794
 795         /* No locks needed, the machine is stopped! */
 796         for (i = 0; i < FTRACE_HASHSIZE; i++) {
 797                 INIT_HLIST_HEAD(&temp_list);
 798                 head = &ftrace_hash[i];
 799
 800                 /* all CPUS are stopped, we are safe to modify code */
 801                 hlist_for_each_entry_safe(p, t, n, head, node) {
 802                         /* Skip over failed records which have not been
 803                          * freed. */
 804                         if (p->flags & FTRACE_FL_FAILED)
 805                                 continue;
 806
 807                         /* Unconverted records are always at the head of the
 808                          * hash bucket. Once we encounter a converted record,
 809                          * simply skip over to the next bucket. Saves ftraced
 810                          * some processor cycles (ftrace does its bid for
 811                          * global warming :-p ). */
 812                         if (p->flags & (FTRACE_FL_CONVERTED))
 813                                 break;
 814
 815                         /* Ignore updates to this record's mcount site.
 816                          * Reintroduce this record at the head of this
 817                          * bucket to attempt to "convert" it again if
 818                          * the kprobe on it is unregistered before the
 819                          * next run. */
 820                         if (get_kprobe((void *)p->ip)) {
 821                                 ftrace_del_hash(p);
 822                                 INIT_HLIST_NODE(&p->node);
 823                                 hlist_add_head(&p->node, &temp_list);
 824                                 freeze_record(p);
 825                                 continue;
 826                         } else {
 827                                 unfreeze_record(p);
 828                         }
 829
 830                         /* convert record (i.e, patch mcount-call with NOP) */
 831                         if (ftrace_code_disable(p)) {
 832                                 p->flags |= FTRACE_FL_CONVERTED;
 833                                 ftrace_update_cnt++;
 834                         } else {
 835                                 if ((system_state == SYSTEM_BOOTING) ||
 836                                     !core_kernel_text(p->ip)) {
 837                                         ftrace_del_hash(p);
 838                                         ftrace_free_rec(p);
 839                                 }
 840                         }
 841                 }
 842
 843                 hlist_for_each_entry_safe(p, t, n, &temp_list, node) {
 844                         hlist_del(&p->node);
 845                         INIT_HLIST_NODE(&p->node);
 846                         hlist_add_head(&p->node, head);
 847                 }
 848         }
 849
 850         stop = ftrace_now(raw_smp_processor_id());
 851         ftrace_update_time = stop - start;
 852         ftrace_update_tot_cnt += ftrace_update_cnt;
 853         ftraced_trigger = 0;
 854
 855         ftrace_enabled = save_ftrace_enabled;
 856         ftrace_record_suspend--;
 857
 858         return 0;
 859 }
 860
 861 static int ftrace_update_code(void)
 862 {
 863         if (unlikely(ftrace_disabled) ||
 864             !ftrace_enabled || !ftraced_trigger)
 865                 return 0;
 866
 867         stop_machine(__ftrace_update_code, NULL, NULL);
 868
 869         return 1;
 870 }
 871
 872 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
 873 {
 874         struct ftrace_page *pg;
 875         int cnt;
 876         int i;
 877
 878         /* allocate a few pages */
 879         ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
 880         if (!ftrace_pages_start)
 881                 return -1;
 882
 883         /*
 884          * Allocate a few more pages.
 885          *
 886          * TODO: have some parser search vmlinux before
 887          *   final linking to find all calls to ftrace.
 888          *   Then we can:
 889          *    a) know how many pages to allocate.
 890          *     and/or
 891          *    b) set up the table then.
 892          *
 893          *  The dynamic code is still necessary for
 894          *  modules.
 895          */
 896
 897         pg = ftrace_pages = ftrace_pages_start;
 898
 899         cnt = num_to_init / ENTRIES_PER_PAGE;
 900         pr_info("ftrace: allocating %ld hash entries in %d pages\n",
 901                 num_to_init, cnt);
 902
 903         for (i = 0; i < cnt; i++) {
 904                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
 905
 906                 /* If we fail, we'll try later anyway */
 907                 if (!pg->next)
 908                         break;
 909
 910                 pg = pg->next;
 911         }
 912
 913         return 0;
 914 }
 915
 916 enum {
 917         FTRACE_ITER_FILTER      = (1 << 0),
 918         FTRACE_ITER_CONT        = (1 << 1),
 919         FTRACE_ITER_NOTRACE     = (1 << 2),
 920         FTRACE_ITER_FAILURES    = (1 << 3),
 921 };
 922
 923 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
 924
 925 struct ftrace_iterator {
 926         loff_t                  pos;
 927         struct ftrace_page      *pg;
 928         unsigned                idx;
 929         unsigned                flags;
 930         unsigned char           buffer[FTRACE_BUFF_MAX+1];
 931         unsigned                buffer_idx;
 932         unsigned                filtered;
 933 };
 934
 935 static void *
 936 t_next(struct seq_file *m, void *v, loff_t *pos)
 937 {
 938         struct ftrace_iterator *iter = m->private;
 939         struct dyn_ftrace *rec = NULL;
 940
 941         (*pos)++;
 942
 943         /* should not be called from interrupt context */
 944         spin_lock(&ftrace_lock);
 945  retry:
 946         if (iter->idx >= iter->pg->index) {
 947                 if (iter->pg->next) {
 948                         iter->pg = iter->pg->next;
 949                         iter->idx = 0;
 950                         goto retry;
 951                 }
 952         } else {
 953                 rec = &iter->pg->records[iter->idx++];
 954                 if ((rec->flags & FTRACE_FL_FREE) ||
 955
 956                     (!(iter->flags & FTRACE_ITER_FAILURES) &&
 957                      (rec->flags & FTRACE_FL_FAILED)) ||
 958
 959                     ((iter->flags & FTRACE_ITER_FAILURES) &&
 960                      !(rec->flags & FTRACE_FL_FAILED)) ||
 961
 962                     ((iter->flags & FTRACE_ITER_NOTRACE) &&
 963                      !(rec->flags & FTRACE_FL_NOTRACE))) {
 964                         rec = NULL;
 965                         goto retry;
 966                 }
 967         }
 968         spin_unlock(&ftrace_lock);
 969
 970         iter->pos = *pos;
 971
 972         return rec;
 973 }
 974
 975 static void *t_start(struct seq_file *m, loff_t *pos)
 976 {
 977         struct ftrace_iterator *iter = m->private;
 978         void *p = NULL;
 979         loff_t l = -1;
 980
 981         if (*pos != iter->pos) {
 982                 for (p = t_next(m, p, &l); p && l < *pos; p = t_next(m, p, &l))
 983                         ;
 984         } else {
 985                 l = *pos;
 986                 p = t_next(m, p, &l);
 987         }
 988
 989         return p;
 990 }
 991
 992 static void t_stop(struct seq_file *m, void *p)
 993 {
 994 }
 995
 996 static int t_show(struct seq_file *m, void *v)
 997 {
 998         struct dyn_ftrace *rec = v;
 999         char str[KSYM_SYMBOL_LEN];
1000
1001         if (!rec)
1002                 return 0;
1003
1004         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1005
1006         seq_printf(m, "%s\n", str);
1007
1008         return 0;
1009 }
1010
1011 static struct seq_operations show_ftrace_seq_ops = {
1012         .start = t_start,
1013         .next = t_next,
1014         .stop = t_stop,
1015         .show = t_show,
1016 };
1017
1018 static int
1019 ftrace_avail_open(struct inode *inode, struct file *file)
1020 {
1021         struct ftrace_iterator *iter;
1022         int ret;
1023
1024         if (unlikely(ftrace_disabled))
1025                 return -ENODEV;
1026
1027         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1028         if (!iter)
1029                 return -ENOMEM;
1030
1031         iter->pg = ftrace_pages_start;
1032         iter->pos = -1;
1033
1034         ret = seq_open(file, &show_ftrace_seq_ops);
1035         if (!ret) {
1036                 struct seq_file *m = file->private_data;
1037
1038                 m->private = iter;
1039         } else {
1040                 kfree(iter);
1041         }
1042
1043         return ret;
1044 }
1045
1046 int ftrace_avail_release(struct inode *inode, struct file *file)
1047 {
1048         struct seq_file *m = (struct seq_file *)file->private_data;
1049         struct ftrace_iterator *iter = m->private;
1050
1051         seq_release(inode, file);
1052         kfree(iter);
1053
1054         return 0;
1055 }
1056
1057 static int
1058 ftrace_failures_open(struct inode *inode, struct file *file)
1059 {
1060         int ret;
1061         struct seq_file *m;
1062         struct ftrace_iterator *iter;
1063
1064         ret = ftrace_avail_open(inode, file);
1065         if (!ret) {
1066                 m = (struct seq_file *)file->private_data;
1067                 iter = (struct ftrace_iterator *)m->private;
1068                 iter->flags = FTRACE_ITER_FAILURES;
1069         }
1070
1071         return ret;
1072 }
1073
1074
1075 static void ftrace_filter_reset(int enable)
1076 {
1077         struct ftrace_page *pg;
1078         struct dyn_ftrace *rec;
1079         unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1080         unsigned i;
1081
1082         /* should not be called from interrupt context */
1083         spin_lock(&ftrace_lock);
1084         if (enable)
1085                 ftrace_filtered = 0;
1086         pg = ftrace_pages_start;
1087         while (pg) {
1088                 for (i = 0; i < pg->index; i++) {
1089                         rec = &pg->records[i];
1090                         if (rec->flags & FTRACE_FL_FAILED)
1091                                 continue;
1092                         rec->flags &= ~type;
1093                 }
1094                 pg = pg->next;
1095         }
1096         spin_unlock(&ftrace_lock);
1097 }
1098
1099 static int
1100 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
1101 {
1102         struct ftrace_iterator *iter;
1103         int ret = 0;
1104
1105         if (unlikely(ftrace_disabled))
1106                 return -ENODEV;
1107
1108         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1109         if (!iter)
1110                 return -ENOMEM;
1111
1112         mutex_lock(&ftrace_regex_lock);
1113         if ((file->f_mode & FMODE_WRITE) &&
1114             !(file->f_flags & O_APPEND))
1115                 ftrace_filter_reset(enable);
1116
1117         if (file->f_mode & FMODE_READ) {
1118                 iter->pg = ftrace_pages_start;
1119                 iter->pos = -1;
1120                 iter->flags = enable ? FTRACE_ITER_FILTER :
1121                         FTRACE_ITER_NOTRACE;
1122
1123                 ret = seq_open(file, &show_ftrace_seq_ops);
1124                 if (!ret) {
1125                         struct seq_file *m = file->private_data;
1126                         m->private = iter;
1127                 } else
1128                         kfree(iter);
1129         } else
1130                 file->private_data = iter;
1131         mutex_unlock(&ftrace_regex_lock);
1132
1133         return ret;
1134 }
1135
1136 static int
1137 ftrace_filter_open(struct inode *inode, struct file *file)
1138 {
1139         return ftrace_regex_open(inode, file, 1);
1140 }
1141
1142 static int
1143 ftrace_notrace_open(struct inode *inode, struct file *file)
1144 {
1145         return ftrace_regex_open(inode, file, 0);
1146 }
1147
1148 static ssize_t
1149 ftrace_regex_read(struct file *file, char __user *ubuf,
1150                        size_t cnt, loff_t *ppos)
1151 {
1152         if (file->f_mode & FMODE_READ)
1153                 return seq_read(file, ubuf, cnt, ppos);
1154         else
1155                 return -EPERM;
1156 }
1157
1158 static loff_t
1159 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1160 {
1161         loff_t ret;
1162
1163         if (file->f_mode & FMODE_READ)
1164                 ret = seq_lseek(file, offset, origin);
1165         else
1166                 file->f_pos = ret = 1;
1167
1168         return ret;
1169 }
1170
1171 enum {
1172         MATCH_FULL,
1173         MATCH_FRONT_ONLY,
1174         MATCH_MIDDLE_ONLY,
1175         MATCH_END_ONLY,
1176 };
1177
1178 static void
1179 ftrace_match(unsigned char *buff, int len, int enable)
1180 {
1181         char str[KSYM_SYMBOL_LEN];
1182         char *search = NULL;
1183         struct ftrace_page *pg;
1184         struct dyn_ftrace *rec;
1185         int type = MATCH_FULL;
1186         unsigned long flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1187         unsigned i, match = 0, search_len = 0;
1188
1189         for (i = 0; i < len; i++) {
1190                 if (buff[i] == '*') {
1191                         if (!i) {
1192                                 search = buff + i + 1;
1193                                 type = MATCH_END_ONLY;
1194                                 search_len = len - (i + 1);
1195                         } else {
1196                                 if (type == MATCH_END_ONLY) {
1197                                         type = MATCH_MIDDLE_ONLY;
1198                                 } else {
1199                                         match = i;
1200                                         type = MATCH_FRONT_ONLY;
1201                                 }
1202                                 buff[i] = 0;
1203                                 break;
1204                         }
1205                 }
1206         }
1207
1208         /* should not be called from interrupt context */
1209         spin_lock(&ftrace_lock);
1210         if (enable)
1211                 ftrace_filtered = 1;
1212         pg = ftrace_pages_start;
1213         while (pg) {
1214                 for (i = 0; i < pg->index; i++) {
1215                         int matched = 0;
1216                         char *ptr;
1217
1218                         rec = &pg->records[i];
1219                         if (rec->flags & FTRACE_FL_FAILED)
1220                                 continue;
1221                         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1222                         switch (type) {
1223                         case MATCH_FULL:
1224                                 if (strcmp(str, buff) == 0)
1225                                         matched = 1;
1226                                 break;
1227                         case MATCH_FRONT_ONLY:
1228                                 if (memcmp(str, buff, match) == 0)
1229                                         matched = 1;
1230                                 break;
1231                         case MATCH_MIDDLE_ONLY:
1232                                 if (strstr(str, search))
1233                                         matched = 1;
1234                                 break;
1235                         case MATCH_END_ONLY:
1236                                 ptr = strstr(str, search);
1237                                 if (ptr && (ptr[search_len] == 0))
1238                                         matched = 1;
1239                                 break;
1240                         }
1241                         if (matched)
1242                                 rec->flags |= flag;
1243                 }
1244                 pg = pg->next;
1245         }
1246         spin_unlock(&ftrace_lock);
1247 }
1248
1249 static ssize_t
1250 ftrace_regex_write(struct file *file, const char __user *ubuf,
1251                    size_t cnt, loff_t *ppos, int enable)
1252 {
1253         struct ftrace_iterator *iter;
1254         char ch;
1255         size_t read = 0;
1256         ssize_t ret;
1257
1258         if (!cnt || cnt < 0)
1259                 return 0;
1260
1261         mutex_lock(&ftrace_regex_lock);
1262
1263         if (file->f_mode & FMODE_READ) {
1264                 struct seq_file *m = file->private_data;
1265                 iter = m->private;
1266         } else
1267                 iter = file->private_data;
1268
1269         if (!*ppos) {
1270                 iter->flags &= ~FTRACE_ITER_CONT;
1271                 iter->buffer_idx = 0;
1272         }
1273
1274         ret = get_user(ch, ubuf++);
1275         if (ret)
1276                 goto out;
1277         read++;
1278         cnt--;
1279
1280         if (!(iter->flags & ~FTRACE_ITER_CONT)) {
1281                 /* skip white space */
1282                 while (cnt && isspace(ch)) {
1283                         ret = get_user(ch, ubuf++);
1284                         if (ret)
1285                                 goto out;
1286                         read++;
1287                         cnt--;
1288                 }
1289
1290                 if (isspace(ch)) {
1291                         file->f_pos += read;
1292                         ret = read;
1293                         goto out;
1294                 }
1295
1296                 iter->buffer_idx = 0;
1297         }
1298
1299         while (cnt && !isspace(ch)) {
1300                 if (iter->buffer_idx < FTRACE_BUFF_MAX)
1301                         iter->buffer[iter->buffer_idx++] = ch;
1302                 else {
1303                         ret = -EINVAL;
1304                         goto out;
1305                 }
1306                 ret = get_user(ch, ubuf++);
1307                 if (ret)
1308                         goto out;
1309                 read++;
1310                 cnt--;
1311         }
1312
1313         if (isspace(ch)) {
1314                 iter->filtered++;
1315                 iter->buffer[iter->buffer_idx] = 0;
1316                 ftrace_match(iter->buffer, iter->buffer_idx, enable);
1317                 iter->buffer_idx = 0;
1318         } else
1319                 iter->flags |= FTRACE_ITER_CONT;
1320
1321
1322         file->f_pos += read;
1323
1324         ret = read;
1325  out:
1326         mutex_unlock(&ftrace_regex_lock);
1327
1328         return ret;
1329 }
1330
1331 static ssize_t
1332 ftrace_filter_write(struct file *file, const char __user *ubuf,
1333                     size_t cnt, loff_t *ppos)
1334 {
1335         return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
1336 }
1337
1338 static ssize_t
1339 ftrace_notrace_write(struct file *file, const char __user *ubuf,
1340                      size_t cnt, loff_t *ppos)
1341 {
1342         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
1343 }
1344
1345 static void
1346 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
1347 {
1348         if (unlikely(ftrace_disabled))
1349                 return;
1350
1351         mutex_lock(&ftrace_regex_lock);
1352         if (reset)
1353                 ftrace_filter_reset(enable);
1354         if (buf)
1355                 ftrace_match(buf, len, enable);
1356         mutex_unlock(&ftrace_regex_lock);
1357 }
1358
1359 /**
1360  * ftrace_set_filter - set a function to filter on in ftrace
1361  * @buf - the string that holds the function filter text.
1362  * @len - the length of the string.
1363  * @reset - non zero to reset all filters before applying this filter.
1364  *
1365  * Filters denote which functions should be enabled when tracing is enabled.
1366  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
1367  */
1368 void ftrace_set_filter(unsigned char *buf, int len, int reset)
1369 {
1370         ftrace_set_regex(buf, len, reset, 1);
1371 }
1372
1373 /**
1374  * ftrace_set_notrace - set a function to not trace in ftrace
1375  * @buf - the string that holds the function notrace text.
1376  * @len - the length of the string.
1377  * @reset - non zero to reset all filters before applying this filter.
1378  *
1379  * Notrace Filters denote which functions should not be enabled when tracing
1380  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
1381  * for tracing.
1382  */
1383 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
1384 {
1385         ftrace_set_regex(buf, len, reset, 0);
1386 }
1387
1388 static int
1389 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
1390 {
1391         struct seq_file *m = (struct seq_file *)file->private_data;
1392         struct ftrace_iterator *iter;
1393
1394         mutex_lock(&ftrace_regex_lock);
1395         if (file->f_mode & FMODE_READ) {
1396                 iter = m->private;
1397
1398                 seq_release(inode, file);
1399         } else
1400                 iter = file->private_data;
1401
1402         if (iter->buffer_idx) {
1403                 iter->filtered++;
1404                 iter->buffer[iter->buffer_idx] = 0;
1405                 ftrace_match(iter->buffer, iter->buffer_idx, enable);
1406         }
1407
1408         mutex_lock(&ftrace_sysctl_lock);
1409         mutex_lock(&ftraced_lock);
1410         if (iter->filtered && ftraced_suspend && ftrace_enabled)
1411                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
1412         mutex_unlock(&ftraced_lock);
1413         mutex_unlock(&ftrace_sysctl_lock);
1414
1415         kfree(iter);
1416         mutex_unlock(&ftrace_regex_lock);
1417         return 0;
1418 }
1419
1420 static int
1421 ftrace_filter_release(struct inode *inode, struct file *file)
1422 {
1423         return ftrace_regex_release(inode, file, 1);
1424 }
1425
1426 static int
1427 ftrace_notrace_release(struct inode *inode, struct file *file)
1428 {
1429         return ftrace_regex_release(inode, file, 0);
1430 }
1431
1432 static ssize_t
1433 ftraced_read(struct file *filp, char __user *ubuf,
1434                      size_t cnt, loff_t *ppos)
1435 {
1436         /* don't worry about races */
1437         char *buf = ftraced_stop ? "disabled\n" : "enabled\n";
1438         int r = strlen(buf);
1439
1440         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1441 }
1442
1443 static ssize_t
1444 ftraced_write(struct file *filp, const char __user *ubuf,
1445                       size_t cnt, loff_t *ppos)
1446 {
1447         char buf[64];
1448         long val;
1449         int ret;
1450
1451         if (cnt >= sizeof(buf))
1452                 return -EINVAL;
1453
1454         if (copy_from_user(&buf, ubuf, cnt))
1455                 return -EFAULT;
1456
1457         if (strncmp(buf, "enable", 6) == 0)
1458                 val = 1;
1459         else if (strncmp(buf, "disable", 7) == 0)
1460                 val = 0;
1461         else {
1462                 buf[cnt] = 0;
1463
1464                 ret = strict_strtoul(buf, 10, &val);
1465                 if (ret < 0)
1466                         return ret;
1467
1468                 val = !!val;
1469         }
1470
1471         if (val)
1472                 ftrace_enable_daemon();
1473         else
1474                 ftrace_disable_daemon();
1475
1476         filp->f_pos += cnt;
1477
1478         return cnt;
1479 }
1480
1481 static struct file_operations ftrace_avail_fops = {
1482         .open = ftrace_avail_open,
1483         .read = seq_read,
1484         .llseek = seq_lseek,
1485         .release = ftrace_avail_release,
1486 };
1487
1488 static struct file_operations ftrace_failures_fops = {
1489         .open = ftrace_failures_open,
1490         .read = seq_read,
1491         .llseek = seq_lseek,
1492         .release = ftrace_avail_release,
1493 };
1494
1495 static struct file_operations ftrace_filter_fops = {
1496         .open = ftrace_filter_open,
1497         .read = ftrace_regex_read,
1498         .write = ftrace_filter_write,
1499         .llseek = ftrace_regex_lseek,
1500         .release = ftrace_filter_release,
1501 };
1502
1503 static struct file_operations ftrace_notrace_fops = {
1504         .open = ftrace_notrace_open,
1505         .read = ftrace_regex_read,
1506         .write = ftrace_notrace_write,
1507         .llseek = ftrace_regex_lseek,
1508         .release = ftrace_notrace_release,
1509 };
1510
1511 static struct file_operations ftraced_fops = {
1512         .open = tracing_open_generic,
1513         .read = ftraced_read,
1514         .write = ftraced_write,
1515 };
1516
1517 /**
1518  * ftrace_force_update - force an update to all recording ftrace functions
1519  */
1520 int ftrace_force_update(void)
1521 {
1522         int ret = 0;
1523
1524         if (unlikely(ftrace_disabled))
1525                 return -ENODEV;
1526
1527         mutex_lock(&ftrace_sysctl_lock);
1528         mutex_lock(&ftraced_lock);
1529
1530         /*
1531          * If ftraced_trigger is not set, then there is nothing
1532          * to update.
1533          */
1534         if (ftraced_trigger && !ftrace_update_code())
1535                 ret = -EBUSY;
1536
1537         mutex_unlock(&ftraced_lock);
1538         mutex_unlock(&ftrace_sysctl_lock);
1539
1540         return ret;
1541 }
1542
1543 static void ftrace_force_shutdown(void)
1544 {
1545         struct task_struct *task;
1546         int command = FTRACE_DISABLE_CALLS | FTRACE_UPDATE_TRACE_FUNC;
1547
1548         mutex_lock(&ftraced_lock);
1549         task = ftraced_task;
1550         ftraced_task = NULL;
1551         ftraced_suspend = -1;
1552         ftrace_run_update_code(command);
1553         mutex_unlock(&ftraced_lock);
1554
1555         if (task)
1556                 kthread_stop(task);
1557 }
1558
1559 static __init int ftrace_init_debugfs(void)
1560 {
1561         struct dentry *d_tracer;
1562         struct dentry *entry;
1563
1564         d_tracer = tracing_init_dentry();
1565
1566         entry = debugfs_create_file("available_filter_functions", 0444,
1567                                     d_tracer, NULL, &ftrace_avail_fops);
1568         if (!entry)
1569                 pr_warning("Could not create debugfs "
1570                            "'available_filter_functions' entry\n");
1571
1572         entry = debugfs_create_file("failures", 0444,
1573                                     d_tracer, NULL, &ftrace_failures_fops);
1574         if (!entry)
1575                 pr_warning("Could not create debugfs 'failures' entry\n");
1576
1577         entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer,
1578                                     NULL, &ftrace_filter_fops);
1579         if (!entry)
1580                 pr_warning("Could not create debugfs "
1581                            "'set_ftrace_filter' entry\n");
1582
1583         entry = debugfs_create_file("set_ftrace_notrace", 0644, d_tracer,
1584                                     NULL, &ftrace_notrace_fops);
1585         if (!entry)
1586                 pr_warning("Could not create debugfs "
1587                            "'set_ftrace_notrace' entry\n");
1588
1589         entry = debugfs_create_file("ftraced_enabled", 0644, d_tracer,
1590                                     NULL, &ftraced_fops);
1591         if (!entry)
1592                 pr_warning("Could not create debugfs "
1593                            "'ftraced_enabled' entry\n");
1594         return 0;
1595 }
1596
1597 fs_initcall(ftrace_init_debugfs);
1598
1599 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
1600 static int ftrace_convert_nops(unsigned long *start,
1601                                unsigned long *end)
1602 {
1603         unsigned long *p;
1604         unsigned long addr;
1605         unsigned long flags;
1606
1607         p = start;
1608         while (p < end) {
1609                 addr = ftrace_call_adjust(*p++);
1610                 /* should not be called from interrupt context */
1611                 spin_lock(&ftrace_lock);
1612                 ftrace_record_ip(addr);
1613                 spin_unlock(&ftrace_lock);
1614                 ftrace_shutdown_replenish();
1615         }
1616
1617         /* p is ignored */
1618         local_irq_save(flags);
1619         __ftrace_update_code(p);
1620         local_irq_restore(flags);
1621
1622         return 0;
1623 }
1624
1625 void ftrace_init_module(unsigned long *start, unsigned long *end)
1626 {
1627         if (ftrace_disabled || start == end)
1628                 return;
1629         ftrace_convert_nops(start, end);
1630 }
1631
1632 extern unsigned long __start_mcount_loc[];
1633 extern unsigned long __stop_mcount_loc[];
1634
1635 void __init ftrace_init(void)
1636 {
1637         unsigned long count, addr, flags;
1638         int ret;
1639
1640         /* Keep the ftrace pointer to the stub */
1641         addr = (unsigned long)ftrace_stub;
1642
1643         local_irq_save(flags);
1644         ftrace_dyn_arch_init(&addr);
1645         local_irq_restore(flags);
1646
1647         /* ftrace_dyn_arch_init places the return code in addr */
1648         if (addr)
1649                 goto failed;
1650
1651         count = __stop_mcount_loc - __start_mcount_loc;
1652
1653         ret = ftrace_dyn_table_alloc(count);
1654         if (ret)
1655                 goto failed;
1656
1657         last_ftrace_enabled = ftrace_enabled = 1;
1658
1659         ret = ftrace_convert_nops(__start_mcount_loc,
1660                                   __stop_mcount_loc);
1661
1662         return;
1663  failed:
1664         ftrace_disabled = 1;
1665 }
1666 #else /* CONFIG_FTRACE_MCOUNT_RECORD */
1667
1668 static void ftrace_release_hash(unsigned long start, unsigned long end)
1669 {
1670         struct dyn_ftrace *rec;
1671         struct hlist_node *t, *n;
1672         struct hlist_head *head, temp_list;
1673         unsigned long flags;
1674         int i, cpu;
1675
1676         preempt_disable_notrace();
1677
1678         /* disable incase we call something that calls mcount */
1679         cpu = raw_smp_processor_id();
1680         per_cpu(ftrace_shutdown_disable_cpu, cpu)++;
1681
1682         ftrace_hash_lock(flags);
1683
1684         for (i = 0; i < FTRACE_HASHSIZE; i++) {
1685                 INIT_HLIST_HEAD(&temp_list);
1686                 head = &ftrace_hash[i];
1687
1688                 /* all CPUS are stopped, we are safe to modify code */
1689                 hlist_for_each_entry_safe(rec, t, n, head, node) {
1690                         if (rec->flags & FTRACE_FL_FREE)
1691                                 continue;
1692
1693                         if ((rec->ip >= start) && (rec->ip < end))
1694                                 ftrace_free_rec(rec);
1695                 }
1696         }
1697
1698         ftrace_hash_unlock(flags);
1699
1700         per_cpu(ftrace_shutdown_disable_cpu, cpu)--;
1701         preempt_enable_notrace();
1702
1703 }
1704
1705 static int ftraced(void *ignore)
1706 {
1707         unsigned long usecs;
1708
1709         while (!kthread_should_stop()) {
1710
1711                 set_current_state(TASK_INTERRUPTIBLE);
1712
1713                 /* check once a second */
1714                 schedule_timeout(HZ);
1715
1716                 if (unlikely(ftrace_disabled))
1717                         continue;
1718
1719                 mutex_lock(&ftrace_sysctl_lock);
1720                 mutex_lock(&ftraced_lock);
1721                 if (!ftraced_suspend && !ftraced_stop &&
1722                     ftrace_update_code()) {
1723                         usecs = nsecs_to_usecs(ftrace_update_time);
1724                         if (ftrace_update_tot_cnt > 100000) {
1725                                 ftrace_update_tot_cnt = 0;
1726                                 pr_info("hm, dftrace overflow: %lu change%s"
1727                                         " (%lu total) in %lu usec%s\n",
1728                                         ftrace_update_cnt,
1729                                         ftrace_update_cnt != 1 ? "s" : "",
1730                                         ftrace_update_tot_cnt,
1731                                         usecs, usecs != 1 ? "s" : "");
1732                                 ftrace_disabled = 1;
1733                                 WARN_ON_ONCE(1);
1734                         }
1735                 }
1736                 mutex_unlock(&ftraced_lock);
1737                 mutex_unlock(&ftrace_sysctl_lock);
1738
1739                 ftrace_shutdown_replenish();
1740         }
1741         __set_current_state(TASK_RUNNING);
1742         return 0;
1743 }
1744
1745 static int __init ftrace_dynamic_init(void)
1746 {
1747         struct task_struct *p;
1748         unsigned long addr;
1749         int ret;
1750
1751         addr = (unsigned long)ftrace_record_ip;
1752
1753         stop_machine(ftrace_dyn_arch_init, &addr, NULL);
1754
1755         /* ftrace_dyn_arch_init places the return code in addr */
1756         if (addr) {
1757                 ret = (int)addr;
1758                 goto failed;
1759         }
1760
1761         ret = ftrace_dyn_table_alloc(NR_TO_INIT);
1762         if (ret)
1763                 goto failed;
1764
1765         p = kthread_run(ftraced, NULL, "ftraced");
1766         if (IS_ERR(p)) {
1767                 ret = -1;
1768                 goto failed;
1769         }
1770
1771         last_ftrace_enabled = ftrace_enabled = 1;
1772         ftraced_task = p;
1773
1774         return 0;
1775
1776  failed:
1777         ftrace_disabled = 1;
1778         return ret;
1779 }
1780
1781 core_initcall(ftrace_dynamic_init);
1782 #endif /* CONFIG_FTRACE_MCOUNT_RECORD */
1783
1784 #else
1785 # define ftrace_startup()               do { } while (0)
1786 # define ftrace_shutdown()              do { } while (0)
1787 # define ftrace_startup_sysctl()        do { } while (0)
1788 # define ftrace_shutdown_sysctl()       do { } while (0)
1789 # define ftrace_force_shutdown()        do { } while (0)
1790 #endif /* CONFIG_DYNAMIC_FTRACE */
1791
1792 /**
1793  * ftrace_kill_atomic - kill ftrace from critical sections
1794  *
1795  * This function should be used by panic code. It stops ftrace
1796  * but in a not so nice way. If you need to simply kill ftrace
1797  * from a non-atomic section, use ftrace_kill.
1798  */
1799 void ftrace_kill_atomic(void)
1800 {
1801         ftrace_disabled = 1;
1802         ftrace_enabled = 0;
1803 #ifdef CONFIG_DYNAMIC_FTRACE
1804         ftraced_suspend = -1;
1805 #endif
1806         clear_ftrace_function();
1807 }
1808
1809 /**
1810  * ftrace_kill - totally shutdown ftrace
1811  *
1812  * This is a safety measure. If something was detected that seems
1813  * wrong, calling this function will keep ftrace from doing
1814  * any more modifications, and updates.
1815  * used when something went wrong.
1816  */
1817 void ftrace_kill(void)
1818 {
1819         mutex_lock(&ftrace_sysctl_lock);
1820         ftrace_disabled = 1;
1821         ftrace_enabled = 0;
1822
1823         clear_ftrace_function();
1824         mutex_unlock(&ftrace_sysctl_lock);
1825
1826         /* Try to totally disable ftrace */
1827         ftrace_force_shutdown();
1828 }
1829
1830 /**
1831  * register_ftrace_function - register a function for profiling
1832  * @ops - ops structure that holds the function for profiling.
1833  *
1834  * Register a function to be called by all functions in the
1835  * kernel.
1836  *
1837  * Note: @ops->func and all the functions it calls must be labeled
1838  *       with "notrace", otherwise it will go into a
1839  *       recursive loop.
1840  */
1841 int register_ftrace_function(struct ftrace_ops *ops)
1842 {
1843         int ret;
1844
1845         if (unlikely(ftrace_disabled))
1846                 return -1;
1847
1848         mutex_lock(&ftrace_sysctl_lock);
1849         ret = __register_ftrace_function(ops);
1850         ftrace_startup();
1851         mutex_unlock(&ftrace_sysctl_lock);
1852
1853         return ret;
1854 }
1855
1856 /**
1857  * unregister_ftrace_function - unresgister a function for profiling.
1858  * @ops - ops structure that holds the function to unregister
1859  *
1860  * Unregister a function that was added to be called by ftrace profiling.
1861  */
1862 int unregister_ftrace_function(struct ftrace_ops *ops)
1863 {
1864         int ret;
1865
1866         mutex_lock(&ftrace_sysctl_lock);
1867         ret = __unregister_ftrace_function(ops);
1868         ftrace_shutdown();
1869         mutex_unlock(&ftrace_sysctl_lock);
1870
1871         return ret;
1872 }
1873
1874 int
1875 ftrace_enable_sysctl(struct ctl_table *table, int write,
1876                      struct file *file, void __user *buffer, size_t *lenp,
1877                      loff_t *ppos)
1878 {
1879         int ret;
1880
1881         if (unlikely(ftrace_disabled))
1882                 return -ENODEV;
1883
1884         mutex_lock(&ftrace_sysctl_lock);
1885
1886         ret  = proc_dointvec(table, write, file, buffer, lenp, ppos);
1887
1888         if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
1889                 goto out;
1890
1891         last_ftrace_enabled = ftrace_enabled;
1892
1893         if (ftrace_enabled) {
1894
1895                 ftrace_startup_sysctl();
1896
1897                 /* we are starting ftrace again */
1898                 if (ftrace_list != &ftrace_list_end) {
1899                         if (ftrace_list->next == &ftrace_list_end)
1900                                 ftrace_trace_function = ftrace_list->func;
1901                         else
1902                                 ftrace_trace_function = ftrace_list_func;
1903                 }
1904
1905         } else {
1906                 /* stopping ftrace calls (just send to ftrace_stub) */
1907                 ftrace_trace_function = ftrace_stub;
1908
1909                 ftrace_shutdown_sysctl();
1910         }
1911
1912  out:
1913         mutex_unlock(&ftrace_sysctl_lock);
1914         return ret;
1915 }