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 #define FTRACE_WARN_ON(cond)                    \
  36         do {                                    \
  37                 if (WARN_ON(cond))              \
  38                         ftrace_kill();          \
  39         } while (0)
  40
  41 #define FTRACE_WARN_ON_ONCE(cond)               \
  42         do {                                    \
  43                 if (WARN_ON_ONCE(cond))         \
  44                         ftrace_kill();          \
  45         } while (0)
  46
  47 /* ftrace_enabled is a method to turn ftrace on or off */
  48 int ftrace_enabled __read_mostly;
  49 static int last_ftrace_enabled;
  50
  51 /*
  52  * ftrace_disabled is set when an anomaly is discovered.
  53  * ftrace_disabled is much stronger than ftrace_enabled.
  54  */
  55 static int ftrace_disabled __read_mostly;
  56
  57 static DEFINE_SPINLOCK(ftrace_lock);
  58 static DEFINE_MUTEX(ftrace_sysctl_lock);
  59
  60 static struct ftrace_ops ftrace_list_end __read_mostly =
  61 {
  62         .func = ftrace_stub,
  63 };
  64
  65 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
  66 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
  67
  68 static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
  69 {
  70         struct ftrace_ops *op = ftrace_list;
  71
  72         /* in case someone actually ports this to alpha! */
  73         read_barrier_depends();
  74
  75         while (op != &ftrace_list_end) {
  76                 /* silly alpha */
  77                 read_barrier_depends();
  78                 op->func(ip, parent_ip);
  79                 op = op->next;
  80         };
  81 }
  82
  83 /**
  84  * clear_ftrace_function - reset the ftrace function
  85  *
  86  * This NULLs the ftrace function and in essence stops
  87  * tracing.  There may be lag
  88  */
  89 void clear_ftrace_function(void)
  90 {
  91         ftrace_trace_function = ftrace_stub;
  92 }
  93
  94 static int __register_ftrace_function(struct ftrace_ops *ops)
  95 {
  96         /* should not be called from interrupt context */
  97         spin_lock(&ftrace_lock);
  98
  99         ops->next = ftrace_list;
 100         /*
 101          * We are entering ops into the ftrace_list but another
 102          * CPU might be walking that list. We need to make sure
 103          * the ops->next pointer is valid before another CPU sees
 104          * the ops pointer included into the ftrace_list.
 105          */
 106         smp_wmb();
 107         ftrace_list = ops;
 108
 109         if (ftrace_enabled) {
 110                 /*
 111                  * For one func, simply call it directly.
 112                  * For more than one func, call the chain.
 113                  */
 114                 if (ops->next == &ftrace_list_end)
 115                         ftrace_trace_function = ops->func;
 116                 else
 117                         ftrace_trace_function = ftrace_list_func;
 118         }
 119
 120         spin_unlock(&ftrace_lock);
 121
 122         return 0;
 123 }
 124
 125 static int __unregister_ftrace_function(struct ftrace_ops *ops)
 126 {
 127         struct ftrace_ops **p;
 128         int ret = 0;
 129
 130         /* should not be called from interrupt context */
 131         spin_lock(&ftrace_lock);
 132
 133         /*
 134          * If we are removing the last function, then simply point
 135          * to the ftrace_stub.
 136          */
 137         if (ftrace_list == ops && ops->next == &ftrace_list_end) {
 138                 ftrace_trace_function = ftrace_stub;
 139                 ftrace_list = &ftrace_list_end;
 140                 goto out;
 141         }
 142
 143         for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
 144                 if (*p == ops)
 145                         break;
 146
 147         if (*p != ops) {
 148                 ret = -1;
 149                 goto out;
 150         }
 151
 152         *p = (*p)->next;
 153
 154         if (ftrace_enabled) {
 155                 /* If we only have one func left, then call that directly */
 156                 if (ftrace_list == &ftrace_list_end ||
 157                     ftrace_list->next == &ftrace_list_end)
 158                         ftrace_trace_function = ftrace_list->func;
 159         }
 160
 161  out:
 162         spin_unlock(&ftrace_lock);
 163
 164         return ret;
 165 }
 166
 167 #ifdef CONFIG_DYNAMIC_FTRACE
 168
 169 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
 170 /*
 171  * The hash lock is only needed when the recording of the mcount
 172  * callers are dynamic. That is, by the caller themselves and
 173  * not recorded via the compilation.
 174  */
 175 static DEFINE_SPINLOCK(ftrace_hash_lock);
 176 #define ftrace_hash_lock(flags)   spin_lock_irqsave(&ftrace_hash_lock, flags)
 177 #define ftrace_hash_unlock(flags) \
 178                         spin_unlock_irqrestore(&ftrace_hash_lock, flags)
 179 static void ftrace_release_hash(unsigned long start, unsigned long end);
 180 #else
 181 /* This is protected via the ftrace_lock with MCOUNT_RECORD. */
 182 #define ftrace_hash_lock(flags)   do { (void)(flags); } while (0)
 183 #define ftrace_hash_unlock(flags) do { } while(0)
 184 static inline void ftrace_release_hash(unsigned long start, unsigned long end)
 185 {
 186 }
 187 #endif
 188
 189 /*
 190  * Since MCOUNT_ADDR may point to mcount itself, we do not want
 191  * to get it confused by reading a reference in the code as we
 192  * are parsing on objcopy output of text. Use a variable for
 193  * it instead.
 194  */
 195 static unsigned long mcount_addr = MCOUNT_ADDR;
 196
 197 static struct task_struct *ftraced_task;
 198
 199 enum {
 200         FTRACE_ENABLE_CALLS             = (1 << 0),
 201         FTRACE_DISABLE_CALLS            = (1 << 1),
 202         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 203         FTRACE_ENABLE_MCOUNT            = (1 << 3),
 204         FTRACE_DISABLE_MCOUNT           = (1 << 4),
 205 };
 206
 207 static int ftrace_filtered;
 208 static int tracing_on;
 209 static int frozen_record_count;
 210
 211 static struct hlist_head ftrace_hash[FTRACE_HASHSIZE];
 212
 213 static DEFINE_PER_CPU(int, ftrace_shutdown_disable_cpu);
 214
 215 static DEFINE_MUTEX(ftraced_lock);
 216 static DEFINE_MUTEX(ftrace_regex_lock);
 217
 218 struct ftrace_page {
 219         struct ftrace_page      *next;
 220         unsigned long           index;
 221         struct dyn_ftrace       records[];
 222 };
 223
 224 #define ENTRIES_PER_PAGE \
 225   ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
 226
 227 /* estimate from running different kernels */
 228 #define NR_TO_INIT              10000
 229
 230 static struct ftrace_page       *ftrace_pages_start;
 231 static struct ftrace_page       *ftrace_pages;
 232
 233 static int ftraced_trigger;
 234 static int ftraced_suspend;
 235 static int ftraced_stop;
 236
 237 static int ftrace_record_suspend;
 238
 239 static struct dyn_ftrace *ftrace_free_records;
 240
 241
 242 #ifdef CONFIG_KPROBES
 243 static inline void freeze_record(struct dyn_ftrace *rec)
 244 {
 245         if (!(rec->flags & FTRACE_FL_FROZEN)) {
 246                 rec->flags |= FTRACE_FL_FROZEN;
 247                 frozen_record_count++;
 248         }
 249 }
 250
 251 static inline void unfreeze_record(struct dyn_ftrace *rec)
 252 {
 253         if (rec->flags & FTRACE_FL_FROZEN) {
 254                 rec->flags &= ~FTRACE_FL_FROZEN;
 255                 frozen_record_count--;
 256         }
 257 }
 258
 259 static inline int record_frozen(struct dyn_ftrace *rec)
 260 {
 261         return rec->flags & FTRACE_FL_FROZEN;
 262 }
 263 #else
 264 # define freeze_record(rec)                     ({ 0; })
 265 # define unfreeze_record(rec)                   ({ 0; })
 266 # define record_frozen(rec)                     ({ 0; })
 267 #endif /* CONFIG_KPROBES */
 268
 269 int skip_trace(unsigned long ip)
 270 {
 271         unsigned long fl;
 272         struct dyn_ftrace *rec;
 273         struct hlist_node *t;
 274         struct hlist_head *head;
 275
 276         if (frozen_record_count == 0)
 277                 return 0;
 278
 279         head = &ftrace_hash[hash_long(ip, FTRACE_HASHBITS)];
 280         hlist_for_each_entry_rcu(rec, t, head, node) {
 281                 if (rec->ip == ip) {
 282                         if (record_frozen(rec)) {
 283                                 if (rec->flags & FTRACE_FL_FAILED)
 284                                         return 1;
 285
 286                                 if (!(rec->flags & FTRACE_FL_CONVERTED))
 287                                         return 1;
 288
 289                                 if (!tracing_on || !ftrace_enabled)
 290                                         return 1;
 291
 292                                 if (ftrace_filtered) {
 293                                         fl = rec->flags & (FTRACE_FL_FILTER |
 294                                                            FTRACE_FL_NOTRACE);
 295                                         if (!fl || (fl & FTRACE_FL_NOTRACE))
 296                                                 return 1;
 297                                 }
 298                         }
 299                         break;
 300                 }
 301         }
 302
 303         return 0;
 304 }
 305
 306 static inline int
 307 ftrace_ip_in_hash(unsigned long ip, unsigned long key)
 308 {
 309         struct dyn_ftrace *p;
 310         struct hlist_node *t;
 311         int found = 0;
 312
 313         hlist_for_each_entry_rcu(p, t, &ftrace_hash[key], node) {
 314                 if (p->ip == ip) {
 315                         found = 1;
 316                         break;
 317                 }
 318         }
 319
 320         return found;
 321 }
 322
 323 static inline void
 324 ftrace_add_hash(struct dyn_ftrace *node, unsigned long key)
 325 {
 326         hlist_add_head_rcu(&node->node, &ftrace_hash[key]);
 327 }
 328
 329 /* called from kstop_machine */
 330 static inline void ftrace_del_hash(struct dyn_ftrace *node)
 331 {
 332         hlist_del(&node->node);
 333 }
 334
 335 static void ftrace_free_rec(struct dyn_ftrace *rec)
 336 {
 337         rec->ip = (unsigned long)ftrace_free_records;
 338         ftrace_free_records = rec;
 339         rec->flags |= FTRACE_FL_FREE;
 340 }
 341
 342 void ftrace_release(void *start, unsigned long size)
 343 {
 344         struct dyn_ftrace *rec;
 345         struct ftrace_page *pg;
 346         unsigned long s = (unsigned long)start;
 347         unsigned long e = s + size;
 348         int i;
 349
 350         if (ftrace_disabled || !start)
 351                 return;
 352
 353         /* should not be called from interrupt context */
 354         spin_lock(&ftrace_lock);
 355
 356         for (pg = ftrace_pages_start; pg; pg = pg->next) {
 357                 for (i = 0; i < pg->index; i++) {
 358                         rec = &pg->records[i];
 359
 360                         if ((rec->ip >= s) && (rec->ip < e))
 361                                 ftrace_free_rec(rec);
 362                 }
 363         }
 364         spin_unlock(&ftrace_lock);
 365
 366         ftrace_release_hash(s, e);
 367 }
 368
 369 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
 370 {
 371         struct dyn_ftrace *rec;
 372
 373         /* First check for freed records */
 374         if (ftrace_free_records) {
 375                 rec = ftrace_free_records;
 376
 377                 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
 378                         FTRACE_WARN_ON_ONCE(1);
 379                         ftrace_free_records = NULL;
 380                         return NULL;
 381                 }
 382
 383                 ftrace_free_records = (void *)rec->ip;
 384                 memset(rec, 0, sizeof(*rec));
 385                 return rec;
 386         }
 387
 388         if (ftrace_pages->index == ENTRIES_PER_PAGE) {
 389                 if (!ftrace_pages->next)
 390                         return NULL;
 391                 ftrace_pages = ftrace_pages->next;
 392         }
 393
 394         return &ftrace_pages->records[ftrace_pages->index++];
 395 }
 396
 397 static void
 398 ftrace_record_ip(unsigned long ip)
 399 {
 400         struct dyn_ftrace *node;
 401         unsigned long flags;
 402         unsigned long key;
 403         int resched;
 404         int cpu;
 405
 406         if (!ftrace_enabled || ftrace_disabled)
 407                 return;
 408
 409         resched = need_resched();
 410         preempt_disable_notrace();
 411
 412         /*
 413          * We simply need to protect against recursion.
 414          * Use the the raw version of smp_processor_id and not
 415          * __get_cpu_var which can call debug hooks that can
 416          * cause a recursive crash here.
 417          */
 418         cpu = raw_smp_processor_id();
 419         per_cpu(ftrace_shutdown_disable_cpu, cpu)++;
 420         if (per_cpu(ftrace_shutdown_disable_cpu, cpu) != 1)
 421                 goto out;
 422
 423         if (unlikely(ftrace_record_suspend))
 424                 goto out;
 425
 426         key = hash_long(ip, FTRACE_HASHBITS);
 427
 428         FTRACE_WARN_ON_ONCE(key >= FTRACE_HASHSIZE);
 429
 430         if (ftrace_ip_in_hash(ip, key))
 431                 goto out;
 432
 433         ftrace_hash_lock(flags);
 434
 435         /* This ip may have hit the hash before the lock */
 436         if (ftrace_ip_in_hash(ip, key))
 437                 goto out_unlock;
 438
 439         node = ftrace_alloc_dyn_node(ip);
 440         if (!node)
 441                 goto out_unlock;
 442
 443         node->ip = ip;
 444
 445         ftrace_add_hash(node, key);
 446
 447         ftraced_trigger = 1;
 448
 449  out_unlock:
 450         ftrace_hash_unlock(flags);
 451  out:
 452         per_cpu(ftrace_shutdown_disable_cpu, cpu)--;
 453
 454         /* prevent recursion with scheduler */
 455         if (resched)
 456                 preempt_enable_no_resched_notrace();
 457         else
 458                 preempt_enable_notrace();
 459 }
 460
 461 #define FTRACE_ADDR ((long)(ftrace_caller))
 462
 463 static int
 464 __ftrace_replace_code(struct dyn_ftrace *rec,
 465                       unsigned char *old, unsigned char *new, int enable)
 466 {
 467         unsigned long ip, fl;
 468
 469         ip = rec->ip;
 470
 471         if (ftrace_filtered && enable) {
 472                 /*
 473                  * If filtering is on:
 474                  *
 475                  * If this record is set to be filtered and
 476                  * is enabled then do nothing.
 477                  *
 478                  * If this record is set to be filtered and
 479                  * it is not enabled, enable it.
 480                  *
 481                  * If this record is not set to be filtered
 482                  * and it is not enabled do nothing.
 483                  *
 484                  * If this record is set not to trace then
 485                  * do nothing.
 486                  *
 487                  * If this record is set not to trace and
 488                  * it is enabled then disable it.
 489                  *
 490                  * If this record is not set to be filtered and
 491                  * it is enabled, disable it.
 492                  */
 493
 494                 fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_NOTRACE |
 495                                    FTRACE_FL_ENABLED);
 496
 497                 if ((fl ==  (FTRACE_FL_FILTER | FTRACE_FL_ENABLED)) ||
 498                     (fl ==  (FTRACE_FL_FILTER | FTRACE_FL_NOTRACE)) ||
 499                     !fl || (fl == FTRACE_FL_NOTRACE))
 500                         return 0;
 501
 502                 /*
 503                  * If it is enabled disable it,
 504                  * otherwise enable it!
 505                  */
 506                 if (fl & FTRACE_FL_ENABLED) {
 507                         /* swap new and old */
 508                         new = old;
 509                         old = ftrace_call_replace(ip, FTRACE_ADDR);
 510                         rec->flags &= ~FTRACE_FL_ENABLED;
 511                 } else {
 512                         new = ftrace_call_replace(ip, FTRACE_ADDR);
 513                         rec->flags |= FTRACE_FL_ENABLED;
 514                 }
 515         } else {
 516
 517                 if (enable) {
 518                         /*
 519                          * If this record is set not to trace and is
 520                          * not enabled, do nothing.
 521                          */
 522                         fl = rec->flags & (FTRACE_FL_NOTRACE | FTRACE_FL_ENABLED);
 523                         if (fl == FTRACE_FL_NOTRACE)
 524                                 return 0;
 525
 526                         new = ftrace_call_replace(ip, FTRACE_ADDR);
 527                 } else
 528                         old = ftrace_call_replace(ip, FTRACE_ADDR);
 529
 530                 if (enable) {
 531                         if (rec->flags & FTRACE_FL_ENABLED)
 532                                 return 0;
 533                         rec->flags |= FTRACE_FL_ENABLED;
 534                 } else {
 535                         if (!(rec->flags & FTRACE_FL_ENABLED))
 536                                 return 0;
 537                         rec->flags &= ~FTRACE_FL_ENABLED;
 538                 }
 539         }
 540
 541         return ftrace_modify_code(ip, old, new);
 542 }
 543
 544 static void ftrace_replace_code(int enable)
 545 {
 546         int i, failed;
 547         unsigned char *new = NULL, *old = NULL;
 548         struct dyn_ftrace *rec;
 549         struct ftrace_page *pg;
 550
 551         if (enable)
 552                 old = ftrace_nop_replace();
 553         else
 554                 new = ftrace_nop_replace();
 555
 556         for (pg = ftrace_pages_start; pg; pg = pg->next) {
 557                 for (i = 0; i < pg->index; i++) {
 558                         rec = &pg->records[i];
 559
 560                         /* don't modify code that has already faulted */
 561                         if (rec->flags & FTRACE_FL_FAILED)
 562                                 continue;
 563
 564                         /* ignore updates to this record's mcount site */
 565                         if (get_kprobe((void *)rec->ip)) {
 566                                 freeze_record(rec);
 567                                 continue;
 568                         } else {
 569                                 unfreeze_record(rec);
 570                         }
 571
 572                         failed = __ftrace_replace_code(rec, old, new, enable);
 573                         if (failed && (rec->flags & FTRACE_FL_CONVERTED)) {
 574                                 rec->flags |= FTRACE_FL_FAILED;
 575                                 if ((system_state == SYSTEM_BOOTING) ||
 576                                     !core_kernel_text(rec->ip)) {
 577                                         ftrace_del_hash(rec);
 578                                         ftrace_free_rec(rec);
 579                                 }
 580                         }
 581                 }
 582         }
 583 }
 584
 585 static void ftrace_shutdown_replenish(void)
 586 {
 587         if (ftrace_pages->next)
 588                 return;
 589
 590         /* allocate another page */
 591         ftrace_pages->next = (void *)get_zeroed_page(GFP_KERNEL);
 592 }
 593
 594 static void print_ip_ins(const char *fmt, unsigned char *p)
 595 {
 596         int i;
 597
 598         printk(KERN_CONT "%s", fmt);
 599
 600         for (i = 0; i < MCOUNT_INSN_SIZE; i++)
 601                 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
 602 }
 603
 604 static int
 605 ftrace_code_disable(struct dyn_ftrace *rec)
 606 {
 607         unsigned long ip;
 608         unsigned char *nop, *call;
 609         int ret;
 610
 611         ip = rec->ip;
 612
 613         nop = ftrace_nop_replace();
 614         call = ftrace_call_replace(ip, mcount_addr);
 615
 616         ret = ftrace_modify_code(ip, call, nop);
 617         if (ret) {
 618                 switch (ret) {
 619                 case -EFAULT:
 620                         FTRACE_WARN_ON_ONCE(1);
 621                         pr_info("ftrace faulted on modifying ");
 622                         print_ip_sym(ip);
 623                         break;
 624                 case -EINVAL:
 625                         FTRACE_WARN_ON_ONCE(1);
 626                         pr_info("ftrace failed to modify ");
 627                         print_ip_sym(ip);
 628                         print_ip_ins(" expected: ", call);
 629                         print_ip_ins(" actual: ", (unsigned char *)ip);
 630                         print_ip_ins(" replace: ", nop);
 631                         printk(KERN_CONT "\n");
 632                         break;
 633                 case -EPERM:
 634                         FTRACE_WARN_ON_ONCE(1);
 635                         pr_info("ftrace faulted on writing ");
 636                         print_ip_sym(ip);
 637                         break;
 638                 default:
 639                         FTRACE_WARN_ON_ONCE(1);
 640                         pr_info("ftrace faulted on unknown error ");
 641                         print_ip_sym(ip);
 642                 }
 643
 644                 rec->flags |= FTRACE_FL_FAILED;
 645                 return 0;
 646         }
 647         return 1;
 648 }
 649
 650 static int __ftrace_update_code(void *ignore);
 651
 652 static int __ftrace_modify_code(void *data)
 653 {
 654         unsigned long addr;
 655         int *command = data;
 656
 657         if (*command & FTRACE_ENABLE_CALLS) {
 658                 /*
 659                  * Update any recorded ips now that we have the
 660                  * machine stopped
 661                  */
 662                 __ftrace_update_code(NULL);
 663                 ftrace_replace_code(1);
 664                 tracing_on = 1;
 665         } else if (*command & FTRACE_DISABLE_CALLS) {
 666                 ftrace_replace_code(0);
 667                 tracing_on = 0;
 668         }
 669
 670         if (*command & FTRACE_UPDATE_TRACE_FUNC)
 671                 ftrace_update_ftrace_func(ftrace_trace_function);
 672
 673         if (*command & FTRACE_ENABLE_MCOUNT) {
 674                 addr = (unsigned long)ftrace_record_ip;
 675                 ftrace_mcount_set(&addr);
 676         } else if (*command & FTRACE_DISABLE_MCOUNT) {
 677                 addr = (unsigned long)ftrace_stub;
 678                 ftrace_mcount_set(&addr);
 679         }
 680
 681         return 0;
 682 }
 683
 684 static void ftrace_run_update_code(int command)
 685 {
 686         stop_machine(__ftrace_modify_code, &command, NULL);
 687 }
 688
 689 void ftrace_disable_daemon(void)
 690 {
 691         /* Stop the daemon from calling kstop_machine */
 692         mutex_lock(&ftraced_lock);
 693         ftraced_stop = 1;
 694         mutex_unlock(&ftraced_lock);
 695
 696         ftrace_force_update();
 697 }
 698
 699 void ftrace_enable_daemon(void)
 700 {
 701         mutex_lock(&ftraced_lock);
 702         ftraced_stop = 0;
 703         mutex_unlock(&ftraced_lock);
 704
 705         ftrace_force_update();
 706 }
 707
 708 static ftrace_func_t saved_ftrace_func;
 709
 710 static void ftrace_startup(void)
 711 {
 712         int command = 0;
 713
 714         if (unlikely(ftrace_disabled))
 715                 return;
 716
 717         mutex_lock(&ftraced_lock);
 718         ftraced_suspend++;
 719         if (ftraced_suspend == 1)
 720                 command |= FTRACE_ENABLE_CALLS;
 721
 722         if (saved_ftrace_func != ftrace_trace_function) {
 723                 saved_ftrace_func = ftrace_trace_function;
 724                 command |= FTRACE_UPDATE_TRACE_FUNC;
 725         }
 726
 727         if (!command || !ftrace_enabled)
 728                 goto out;
 729
 730         ftrace_run_update_code(command);
 731  out:
 732         mutex_unlock(&ftraced_lock);
 733 }
 734
 735 static void ftrace_shutdown(void)
 736 {
 737         int command = 0;
 738
 739         if (unlikely(ftrace_disabled))
 740                 return;
 741
 742         mutex_lock(&ftraced_lock);
 743         ftraced_suspend--;
 744         if (!ftraced_suspend)
 745                 command |= FTRACE_DISABLE_CALLS;
 746
 747         if (saved_ftrace_func != ftrace_trace_function) {
 748                 saved_ftrace_func = ftrace_trace_function;
 749                 command |= FTRACE_UPDATE_TRACE_FUNC;
 750         }
 751
 752         if (!command || !ftrace_enabled)
 753                 goto out;
 754
 755         ftrace_run_update_code(command);
 756  out:
 757         mutex_unlock(&ftraced_lock);
 758 }
 759
 760 static void ftrace_startup_sysctl(void)
 761 {
 762         int command = FTRACE_ENABLE_MCOUNT;
 763
 764         if (unlikely(ftrace_disabled))
 765                 return;
 766
 767         mutex_lock(&ftraced_lock);
 768         /* Force update next time */
 769         saved_ftrace_func = NULL;
 770         /* ftraced_suspend is true if we want ftrace running */
 771         if (ftraced_suspend)
 772                 command |= FTRACE_ENABLE_CALLS;
 773
 774         ftrace_run_update_code(command);
 775         mutex_unlock(&ftraced_lock);
 776 }
 777
 778 static void ftrace_shutdown_sysctl(void)
 779 {
 780         int command = FTRACE_DISABLE_MCOUNT;
 781
 782         if (unlikely(ftrace_disabled))
 783                 return;
 784
 785         mutex_lock(&ftraced_lock);
 786         /* ftraced_suspend is true if ftrace is running */
 787         if (ftraced_suspend)
 788                 command |= FTRACE_DISABLE_CALLS;
 789
 790         ftrace_run_update_code(command);
 791         mutex_unlock(&ftraced_lock);
 792 }
 793
 794 static cycle_t          ftrace_update_time;
 795 static unsigned long    ftrace_update_cnt;
 796 unsigned long           ftrace_update_tot_cnt;
 797
 798 static int __ftrace_update_code(void *ignore)
 799 {
 800         int i, save_ftrace_enabled;
 801         cycle_t start, stop;
 802         struct dyn_ftrace *p;
 803         struct hlist_node *t, *n;
 804         struct hlist_head *head, temp_list;
 805
 806         /* Don't be recording funcs now */
 807         ftrace_record_suspend++;
 808         save_ftrace_enabled = ftrace_enabled;
 809         ftrace_enabled = 0;
 810
 811         start = ftrace_now(raw_smp_processor_id());
 812         ftrace_update_cnt = 0;
 813
 814         /* No locks needed, the machine is stopped! */
 815         for (i = 0; i < FTRACE_HASHSIZE; i++) {
 816                 INIT_HLIST_HEAD(&temp_list);
 817                 head = &ftrace_hash[i];
 818
 819                 /* all CPUS are stopped, we are safe to modify code */
 820                 hlist_for_each_entry_safe(p, t, n, head, node) {
 821                         /* Skip over failed records which have not been
 822                          * freed. */
 823                         if (p->flags & FTRACE_FL_FAILED)
 824                                 continue;
 825
 826                         /* Unconverted records are always at the head of the
 827                          * hash bucket. Once we encounter a converted record,
 828                          * simply skip over to the next bucket. Saves ftraced
 829                          * some processor cycles (ftrace does its bid for
 830                          * global warming :-p ). */
 831                         if (p->flags & (FTRACE_FL_CONVERTED))
 832                                 break;
 833
 834                         /* Ignore updates to this record's mcount site.
 835                          * Reintroduce this record at the head of this
 836                          * bucket to attempt to "convert" it again if
 837                          * the kprobe on it is unregistered before the
 838                          * next run. */
 839                         if (get_kprobe((void *)p->ip)) {
 840                                 ftrace_del_hash(p);
 841                                 INIT_HLIST_NODE(&p->node);
 842                                 hlist_add_head(&p->node, &temp_list);
 843                                 freeze_record(p);
 844                                 continue;
 845                         } else {
 846                                 unfreeze_record(p);
 847                         }
 848
 849                         /* convert record (i.e, patch mcount-call with NOP) */
 850                         if (ftrace_code_disable(p)) {
 851                                 p->flags |= FTRACE_FL_CONVERTED;
 852                                 ftrace_update_cnt++;
 853                         } else {
 854                                 if ((system_state == SYSTEM_BOOTING) ||
 855                                     !core_kernel_text(p->ip)) {
 856                                         ftrace_del_hash(p);
 857                                         ftrace_free_rec(p);
 858                                 }
 859                         }
 860                 }
 861
 862                 hlist_for_each_entry_safe(p, t, n, &temp_list, node) {
 863                         hlist_del(&p->node);
 864                         INIT_HLIST_NODE(&p->node);
 865                         hlist_add_head(&p->node, head);
 866                 }
 867         }
 868
 869         stop = ftrace_now(raw_smp_processor_id());
 870         ftrace_update_time = stop - start;
 871         ftrace_update_tot_cnt += ftrace_update_cnt;
 872         ftraced_trigger = 0;
 873
 874         ftrace_enabled = save_ftrace_enabled;
 875         ftrace_record_suspend--;
 876
 877         return 0;
 878 }
 879
 880 static int ftrace_update_code(void)
 881 {
 882         if (unlikely(ftrace_disabled) ||
 883             !ftrace_enabled || !ftraced_trigger)
 884                 return 0;
 885
 886         stop_machine(__ftrace_update_code, NULL, NULL);
 887
 888         return 1;
 889 }
 890
 891 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
 892 {
 893         struct ftrace_page *pg;
 894         int cnt;
 895         int i;
 896
 897         /* allocate a few pages */
 898         ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
 899         if (!ftrace_pages_start)
 900                 return -1;
 901
 902         /*
 903          * Allocate a few more pages.
 904          *
 905          * TODO: have some parser search vmlinux before
 906          *   final linking to find all calls to ftrace.
 907          *   Then we can:
 908          *    a) know how many pages to allocate.
 909          *     and/or
 910          *    b) set up the table then.
 911          *
 912          *  The dynamic code is still necessary for
 913          *  modules.
 914          */
 915
 916         pg = ftrace_pages = ftrace_pages_start;
 917
 918         cnt = num_to_init / ENTRIES_PER_PAGE;
 919         pr_info("ftrace: allocating %ld hash entries in %d pages\n",
 920                 num_to_init, cnt);
 921
 922         for (i = 0; i < cnt; i++) {
 923                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
 924
 925                 /* If we fail, we'll try later anyway */
 926                 if (!pg->next)
 927                         break;
 928
 929                 pg = pg->next;
 930         }
 931
 932         return 0;
 933 }
 934
 935 enum {
 936         FTRACE_ITER_FILTER      = (1 << 0),
 937         FTRACE_ITER_CONT        = (1 << 1),
 938         FTRACE_ITER_NOTRACE     = (1 << 2),
 939         FTRACE_ITER_FAILURES    = (1 << 3),
 940 };
 941
 942 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
 943
 944 struct ftrace_iterator {
 945         loff_t                  pos;
 946         struct ftrace_page      *pg;
 947         unsigned                idx;
 948         unsigned                flags;
 949         unsigned char           buffer[FTRACE_BUFF_MAX+1];
 950         unsigned                buffer_idx;
 951         unsigned                filtered;
 952 };
 953
 954 static void *
 955 t_next(struct seq_file *m, void *v, loff_t *pos)
 956 {
 957         struct ftrace_iterator *iter = m->private;
 958         struct dyn_ftrace *rec = NULL;
 959
 960         (*pos)++;
 961
 962         /* should not be called from interrupt context */
 963         spin_lock(&ftrace_lock);
 964  retry:
 965         if (iter->idx >= iter->pg->index) {
 966                 if (iter->pg->next) {
 967                         iter->pg = iter->pg->next;
 968                         iter->idx = 0;
 969                         goto retry;
 970                 }
 971         } else {
 972                 rec = &iter->pg->records[iter->idx++];
 973                 if ((rec->flags & FTRACE_FL_FREE) ||
 974
 975                     (!(iter->flags & FTRACE_ITER_FAILURES) &&
 976                      (rec->flags & FTRACE_FL_FAILED)) ||
 977
 978                     ((iter->flags & FTRACE_ITER_FAILURES) &&
 979                      !(rec->flags & FTRACE_FL_FAILED)) ||
 980
 981                     ((iter->flags & FTRACE_ITER_NOTRACE) &&
 982                      !(rec->flags & FTRACE_FL_NOTRACE))) {
 983                         rec = NULL;
 984                         goto retry;
 985                 }
 986         }
 987         spin_unlock(&ftrace_lock);
 988
 989         iter->pos = *pos;
 990
 991         return rec;
 992 }
 993
 994 static void *t_start(struct seq_file *m, loff_t *pos)
 995 {
 996         struct ftrace_iterator *iter = m->private;
 997         void *p = NULL;
 998         loff_t l = -1;
 999
1000         if (*pos != iter->pos) {
1001                 for (p = t_next(m, p, &l); p && l < *pos; p = t_next(m, p, &l))
1002                         ;
1003         } else {
1004                 l = *pos;
1005                 p = t_next(m, p, &l);
1006         }
1007
1008         return p;
1009 }
1010
1011 static void t_stop(struct seq_file *m, void *p)
1012 {
1013 }
1014
1015 static int t_show(struct seq_file *m, void *v)
1016 {
1017         struct dyn_ftrace *rec = v;
1018         char str[KSYM_SYMBOL_LEN];
1019
1020         if (!rec)
1021                 return 0;
1022
1023         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1024
1025         seq_printf(m, "%s\n", str);
1026
1027         return 0;
1028 }
1029
1030 static struct seq_operations show_ftrace_seq_ops = {
1031         .start = t_start,
1032         .next = t_next,
1033         .stop = t_stop,
1034         .show = t_show,
1035 };
1036
1037 static int
1038 ftrace_avail_open(struct inode *inode, struct file *file)
1039 {
1040         struct ftrace_iterator *iter;
1041         int ret;
1042
1043         if (unlikely(ftrace_disabled))
1044                 return -ENODEV;
1045
1046         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1047         if (!iter)
1048                 return -ENOMEM;
1049
1050         iter->pg = ftrace_pages_start;
1051         iter->pos = -1;
1052
1053         ret = seq_open(file, &show_ftrace_seq_ops);
1054         if (!ret) {
1055                 struct seq_file *m = file->private_data;
1056
1057                 m->private = iter;
1058         } else {
1059                 kfree(iter);
1060         }
1061
1062         return ret;
1063 }
1064
1065 int ftrace_avail_release(struct inode *inode, struct file *file)
1066 {
1067         struct seq_file *m = (struct seq_file *)file->private_data;
1068         struct ftrace_iterator *iter = m->private;
1069
1070         seq_release(inode, file);
1071         kfree(iter);
1072
1073         return 0;
1074 }
1075
1076 static int
1077 ftrace_failures_open(struct inode *inode, struct file *file)
1078 {
1079         int ret;
1080         struct seq_file *m;
1081         struct ftrace_iterator *iter;
1082
1083         ret = ftrace_avail_open(inode, file);
1084         if (!ret) {
1085                 m = (struct seq_file *)file->private_data;
1086                 iter = (struct ftrace_iterator *)m->private;
1087                 iter->flags = FTRACE_ITER_FAILURES;
1088         }
1089
1090         return ret;
1091 }
1092
1093
1094 static void ftrace_filter_reset(int enable)
1095 {
1096         struct ftrace_page *pg;
1097         struct dyn_ftrace *rec;
1098         unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1099         unsigned i;
1100
1101         /* should not be called from interrupt context */
1102         spin_lock(&ftrace_lock);
1103         if (enable)
1104                 ftrace_filtered = 0;
1105         pg = ftrace_pages_start;
1106         while (pg) {
1107                 for (i = 0; i < pg->index; i++) {
1108                         rec = &pg->records[i];
1109                         if (rec->flags & FTRACE_FL_FAILED)
1110                                 continue;
1111                         rec->flags &= ~type;
1112                 }
1113                 pg = pg->next;
1114         }
1115         spin_unlock(&ftrace_lock);
1116 }
1117
1118 static int
1119 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
1120 {
1121         struct ftrace_iterator *iter;
1122         int ret = 0;
1123
1124         if (unlikely(ftrace_disabled))
1125                 return -ENODEV;
1126
1127         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1128         if (!iter)
1129                 return -ENOMEM;
1130
1131         mutex_lock(&ftrace_regex_lock);
1132         if ((file->f_mode & FMODE_WRITE) &&
1133             !(file->f_flags & O_APPEND))
1134                 ftrace_filter_reset(enable);
1135
1136         if (file->f_mode & FMODE_READ) {
1137                 iter->pg = ftrace_pages_start;
1138                 iter->pos = -1;
1139                 iter->flags = enable ? FTRACE_ITER_FILTER :
1140                         FTRACE_ITER_NOTRACE;
1141
1142                 ret = seq_open(file, &show_ftrace_seq_ops);
1143                 if (!ret) {
1144                         struct seq_file *m = file->private_data;
1145                         m->private = iter;
1146                 } else
1147                         kfree(iter);
1148         } else
1149                 file->private_data = iter;
1150         mutex_unlock(&ftrace_regex_lock);
1151
1152         return ret;
1153 }
1154
1155 static int
1156 ftrace_filter_open(struct inode *inode, struct file *file)
1157 {
1158         return ftrace_regex_open(inode, file, 1);
1159 }
1160
1161 static int
1162 ftrace_notrace_open(struct inode *inode, struct file *file)
1163 {
1164         return ftrace_regex_open(inode, file, 0);
1165 }
1166
1167 static ssize_t
1168 ftrace_regex_read(struct file *file, char __user *ubuf,
1169                        size_t cnt, loff_t *ppos)
1170 {
1171         if (file->f_mode & FMODE_READ)
1172                 return seq_read(file, ubuf, cnt, ppos);
1173         else
1174                 return -EPERM;
1175 }
1176
1177 static loff_t
1178 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1179 {
1180         loff_t ret;
1181
1182         if (file->f_mode & FMODE_READ)
1183                 ret = seq_lseek(file, offset, origin);
1184         else
1185                 file->f_pos = ret = 1;
1186
1187         return ret;
1188 }
1189
1190 enum {
1191         MATCH_FULL,
1192         MATCH_FRONT_ONLY,
1193         MATCH_MIDDLE_ONLY,
1194         MATCH_END_ONLY,
1195 };
1196
1197 static void
1198 ftrace_match(unsigned char *buff, int len, int enable)
1199 {
1200         char str[KSYM_SYMBOL_LEN];
1201         char *search = NULL;
1202         struct ftrace_page *pg;
1203         struct dyn_ftrace *rec;
1204         int type = MATCH_FULL;
1205         unsigned long flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1206         unsigned i, match = 0, search_len = 0;
1207
1208         for (i = 0; i < len; i++) {
1209                 if (buff[i] == '*') {
1210                         if (!i) {
1211                                 search = buff + i + 1;
1212                                 type = MATCH_END_ONLY;
1213                                 search_len = len - (i + 1);
1214                         } else {
1215                                 if (type == MATCH_END_ONLY) {
1216                                         type = MATCH_MIDDLE_ONLY;
1217                                 } else {
1218                                         match = i;
1219                                         type = MATCH_FRONT_ONLY;
1220                                 }
1221                                 buff[i] = 0;
1222                                 break;
1223                         }
1224                 }
1225         }
1226
1227         /* should not be called from interrupt context */
1228         spin_lock(&ftrace_lock);
1229         if (enable)
1230                 ftrace_filtered = 1;
1231         pg = ftrace_pages_start;
1232         while (pg) {
1233                 for (i = 0; i < pg->index; i++) {
1234                         int matched = 0;
1235                         char *ptr;
1236
1237                         rec = &pg->records[i];
1238                         if (rec->flags & FTRACE_FL_FAILED)
1239                                 continue;
1240                         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1241                         switch (type) {
1242                         case MATCH_FULL:
1243                                 if (strcmp(str, buff) == 0)
1244                                         matched = 1;
1245                                 break;
1246                         case MATCH_FRONT_ONLY:
1247                                 if (memcmp(str, buff, match) == 0)
1248                                         matched = 1;
1249                                 break;
1250                         case MATCH_MIDDLE_ONLY:
1251                                 if (strstr(str, search))
1252                                         matched = 1;
1253                                 break;
1254                         case MATCH_END_ONLY:
1255                                 ptr = strstr(str, search);
1256                                 if (ptr && (ptr[search_len] == 0))
1257                                         matched = 1;
1258                                 break;
1259                         }
1260                         if (matched)
1261                                 rec->flags |= flag;
1262                 }
1263                 pg = pg->next;
1264         }
1265         spin_unlock(&ftrace_lock);
1266 }
1267
1268 static ssize_t
1269 ftrace_regex_write(struct file *file, const char __user *ubuf,
1270                    size_t cnt, loff_t *ppos, int enable)
1271 {
1272         struct ftrace_iterator *iter;
1273         char ch;
1274         size_t read = 0;
1275         ssize_t ret;
1276
1277         if (!cnt || cnt < 0)
1278                 return 0;
1279
1280         mutex_lock(&ftrace_regex_lock);
1281
1282         if (file->f_mode & FMODE_READ) {
1283                 struct seq_file *m = file->private_data;
1284                 iter = m->private;
1285         } else
1286                 iter = file->private_data;
1287
1288         if (!*ppos) {
1289                 iter->flags &= ~FTRACE_ITER_CONT;
1290                 iter->buffer_idx = 0;
1291         }
1292
1293         ret = get_user(ch, ubuf++);
1294         if (ret)
1295                 goto out;
1296         read++;
1297         cnt--;
1298
1299         if (!(iter->flags & ~FTRACE_ITER_CONT)) {
1300                 /* skip white space */
1301                 while (cnt && isspace(ch)) {
1302                         ret = get_user(ch, ubuf++);
1303                         if (ret)
1304                                 goto out;
1305                         read++;
1306                         cnt--;
1307                 }
1308
1309                 if (isspace(ch)) {
1310                         file->f_pos += read;
1311                         ret = read;
1312                         goto out;
1313                 }
1314
1315                 iter->buffer_idx = 0;
1316         }
1317
1318         while (cnt && !isspace(ch)) {
1319                 if (iter->buffer_idx < FTRACE_BUFF_MAX)
1320                         iter->buffer[iter->buffer_idx++] = ch;
1321                 else {
1322                         ret = -EINVAL;
1323                         goto out;
1324                 }
1325                 ret = get_user(ch, ubuf++);
1326                 if (ret)
1327                         goto out;
1328                 read++;
1329                 cnt--;
1330         }
1331
1332         if (isspace(ch)) {
1333                 iter->filtered++;
1334                 iter->buffer[iter->buffer_idx] = 0;
1335                 ftrace_match(iter->buffer, iter->buffer_idx, enable);
1336                 iter->buffer_idx = 0;
1337         } else
1338                 iter->flags |= FTRACE_ITER_CONT;
1339
1340
1341         file->f_pos += read;
1342
1343         ret = read;
1344  out:
1345         mutex_unlock(&ftrace_regex_lock);
1346
1347         return ret;
1348 }
1349
1350 static ssize_t
1351 ftrace_filter_write(struct file *file, const char __user *ubuf,
1352                     size_t cnt, loff_t *ppos)
1353 {
1354         return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
1355 }
1356
1357 static ssize_t
1358 ftrace_notrace_write(struct file *file, const char __user *ubuf,
1359                      size_t cnt, loff_t *ppos)
1360 {
1361         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
1362 }
1363
1364 static void
1365 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
1366 {
1367         if (unlikely(ftrace_disabled))
1368                 return;
1369
1370         mutex_lock(&ftrace_regex_lock);
1371         if (reset)
1372                 ftrace_filter_reset(enable);
1373         if (buf)
1374                 ftrace_match(buf, len, enable);
1375         mutex_unlock(&ftrace_regex_lock);
1376 }
1377
1378 /**
1379  * ftrace_set_filter - set a function to filter on in ftrace
1380  * @buf - the string that holds the function filter text.
1381  * @len - the length of the string.
1382  * @reset - non zero to reset all filters before applying this filter.
1383  *
1384  * Filters denote which functions should be enabled when tracing is enabled.
1385  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
1386  */
1387 void ftrace_set_filter(unsigned char *buf, int len, int reset)
1388 {
1389         ftrace_set_regex(buf, len, reset, 1);
1390 }
1391
1392 /**
1393  * ftrace_set_notrace - set a function to not trace in ftrace
1394  * @buf - the string that holds the function notrace text.
1395  * @len - the length of the string.
1396  * @reset - non zero to reset all filters before applying this filter.
1397  *
1398  * Notrace Filters denote which functions should not be enabled when tracing
1399  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
1400  * for tracing.
1401  */
1402 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
1403 {
1404         ftrace_set_regex(buf, len, reset, 0);
1405 }
1406
1407 static int
1408 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
1409 {
1410         struct seq_file *m = (struct seq_file *)file->private_data;
1411         struct ftrace_iterator *iter;
1412
1413         mutex_lock(&ftrace_regex_lock);
1414         if (file->f_mode & FMODE_READ) {
1415                 iter = m->private;
1416
1417                 seq_release(inode, file);
1418         } else
1419                 iter = file->private_data;
1420
1421         if (iter->buffer_idx) {
1422                 iter->filtered++;
1423                 iter->buffer[iter->buffer_idx] = 0;
1424                 ftrace_match(iter->buffer, iter->buffer_idx, enable);
1425         }
1426
1427         mutex_lock(&ftrace_sysctl_lock);
1428         mutex_lock(&ftraced_lock);
1429         if (iter->filtered && ftraced_suspend && ftrace_enabled)
1430                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
1431         mutex_unlock(&ftraced_lock);
1432         mutex_unlock(&ftrace_sysctl_lock);
1433
1434         kfree(iter);
1435         mutex_unlock(&ftrace_regex_lock);
1436         return 0;
1437 }
1438
1439 static int
1440 ftrace_filter_release(struct inode *inode, struct file *file)
1441 {
1442         return ftrace_regex_release(inode, file, 1);
1443 }
1444
1445 static int
1446 ftrace_notrace_release(struct inode *inode, struct file *file)
1447 {
1448         return ftrace_regex_release(inode, file, 0);
1449 }
1450
1451 static ssize_t
1452 ftraced_read(struct file *filp, char __user *ubuf,
1453                      size_t cnt, loff_t *ppos)
1454 {
1455         /* don't worry about races */
1456         char *buf = ftraced_stop ? "disabled\n" : "enabled\n";
1457         int r = strlen(buf);
1458
1459         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1460 }
1461
1462 static ssize_t
1463 ftraced_write(struct file *filp, const char __user *ubuf,
1464                       size_t cnt, loff_t *ppos)
1465 {
1466         char buf[64];
1467         long val;
1468         int ret;
1469
1470         if (cnt >= sizeof(buf))
1471                 return -EINVAL;
1472
1473         if (copy_from_user(&buf, ubuf, cnt))
1474                 return -EFAULT;
1475
1476         if (strncmp(buf, "enable", 6) == 0)
1477                 val = 1;
1478         else if (strncmp(buf, "disable", 7) == 0)
1479                 val = 0;
1480         else {
1481                 buf[cnt] = 0;
1482
1483                 ret = strict_strtoul(buf, 10, &val);
1484                 if (ret < 0)
1485                         return ret;
1486
1487                 val = !!val;
1488         }
1489
1490         if (val)
1491                 ftrace_enable_daemon();
1492         else
1493                 ftrace_disable_daemon();
1494
1495         filp->f_pos += cnt;
1496
1497         return cnt;
1498 }
1499
1500 static struct file_operations ftrace_avail_fops = {
1501         .open = ftrace_avail_open,
1502         .read = seq_read,
1503         .llseek = seq_lseek,
1504         .release = ftrace_avail_release,
1505 };
1506
1507 static struct file_operations ftrace_failures_fops = {
1508         .open = ftrace_failures_open,
1509         .read = seq_read,
1510         .llseek = seq_lseek,
1511         .release = ftrace_avail_release,
1512 };
1513
1514 static struct file_operations ftrace_filter_fops = {
1515         .open = ftrace_filter_open,
1516         .read = ftrace_regex_read,
1517         .write = ftrace_filter_write,
1518         .llseek = ftrace_regex_lseek,
1519         .release = ftrace_filter_release,
1520 };
1521
1522 static struct file_operations ftrace_notrace_fops = {
1523         .open = ftrace_notrace_open,
1524         .read = ftrace_regex_read,
1525         .write = ftrace_notrace_write,
1526         .llseek = ftrace_regex_lseek,
1527         .release = ftrace_notrace_release,
1528 };
1529
1530 static struct file_operations ftraced_fops = {
1531         .open = tracing_open_generic,
1532         .read = ftraced_read,
1533         .write = ftraced_write,
1534 };
1535
1536 /**
1537  * ftrace_force_update - force an update to all recording ftrace functions
1538  */
1539 int ftrace_force_update(void)
1540 {
1541         int ret = 0;
1542
1543         if (unlikely(ftrace_disabled))
1544                 return -ENODEV;
1545
1546         mutex_lock(&ftrace_sysctl_lock);
1547         mutex_lock(&ftraced_lock);
1548
1549         /*
1550          * If ftraced_trigger is not set, then there is nothing
1551          * to update.
1552          */
1553         if (ftraced_trigger && !ftrace_update_code())
1554                 ret = -EBUSY;
1555
1556         mutex_unlock(&ftraced_lock);
1557         mutex_unlock(&ftrace_sysctl_lock);
1558
1559         return ret;
1560 }
1561
1562 static __init int ftrace_init_debugfs(void)
1563 {
1564         struct dentry *d_tracer;
1565         struct dentry *entry;
1566
1567         d_tracer = tracing_init_dentry();
1568
1569         entry = debugfs_create_file("available_filter_functions", 0444,
1570                                     d_tracer, NULL, &ftrace_avail_fops);
1571         if (!entry)
1572                 pr_warning("Could not create debugfs "
1573                            "'available_filter_functions' entry\n");
1574
1575         entry = debugfs_create_file("failures", 0444,
1576                                     d_tracer, NULL, &ftrace_failures_fops);
1577         if (!entry)
1578                 pr_warning("Could not create debugfs 'failures' entry\n");
1579
1580         entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer,
1581                                     NULL, &ftrace_filter_fops);
1582         if (!entry)
1583                 pr_warning("Could not create debugfs "
1584                            "'set_ftrace_filter' entry\n");
1585
1586         entry = debugfs_create_file("set_ftrace_notrace", 0644, d_tracer,
1587                                     NULL, &ftrace_notrace_fops);
1588         if (!entry)
1589                 pr_warning("Could not create debugfs "
1590                            "'set_ftrace_notrace' entry\n");
1591
1592         entry = debugfs_create_file("ftraced_enabled", 0644, d_tracer,
1593                                     NULL, &ftraced_fops);
1594         if (!entry)
1595                 pr_warning("Could not create debugfs "
1596                            "'ftraced_enabled' entry\n");
1597         return 0;
1598 }
1599
1600 fs_initcall(ftrace_init_debugfs);
1601
1602 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
1603 static int ftrace_convert_nops(unsigned long *start,
1604                                unsigned long *end)
1605 {
1606         unsigned long *p;
1607         unsigned long addr;
1608         unsigned long flags;
1609
1610         p = start;
1611         while (p < end) {
1612                 addr = ftrace_call_adjust(*p++);
1613                 /* should not be called from interrupt context */
1614                 spin_lock(&ftrace_lock);
1615                 ftrace_record_ip(addr);
1616                 spin_unlock(&ftrace_lock);
1617                 ftrace_shutdown_replenish();
1618         }
1619
1620         /* p is ignored */
1621         local_irq_save(flags);
1622         __ftrace_update_code(p);
1623         local_irq_restore(flags);
1624
1625         return 0;
1626 }
1627
1628 void ftrace_init_module(unsigned long *start, unsigned long *end)
1629 {
1630         if (ftrace_disabled || start == end)
1631                 return;
1632         ftrace_convert_nops(start, end);
1633 }
1634
1635 extern unsigned long __start_mcount_loc[];
1636 extern unsigned long __stop_mcount_loc[];
1637
1638 void __init ftrace_init(void)
1639 {
1640         unsigned long count, addr, flags;
1641         int ret;
1642
1643         /* Keep the ftrace pointer to the stub */
1644         addr = (unsigned long)ftrace_stub;
1645
1646         local_irq_save(flags);
1647         ftrace_dyn_arch_init(&addr);
1648         local_irq_restore(flags);
1649
1650         /* ftrace_dyn_arch_init places the return code in addr */
1651         if (addr)
1652                 goto failed;
1653
1654         count = __stop_mcount_loc - __start_mcount_loc;
1655
1656         ret = ftrace_dyn_table_alloc(count);
1657         if (ret)
1658                 goto failed;
1659
1660         last_ftrace_enabled = ftrace_enabled = 1;
1661
1662         ret = ftrace_convert_nops(__start_mcount_loc,
1663                                   __stop_mcount_loc);
1664
1665         return;
1666  failed:
1667         ftrace_disabled = 1;
1668 }
1669 #else /* CONFIG_FTRACE_MCOUNT_RECORD */
1670
1671 static void ftrace_release_hash(unsigned long start, unsigned long end)
1672 {
1673         struct dyn_ftrace *rec;
1674         struct hlist_node *t, *n;
1675         struct hlist_head *head, temp_list;
1676         unsigned long flags;
1677         int i, cpu;
1678
1679         preempt_disable_notrace();
1680
1681         /* disable incase we call something that calls mcount */
1682         cpu = raw_smp_processor_id();
1683         per_cpu(ftrace_shutdown_disable_cpu, cpu)++;
1684
1685         ftrace_hash_lock(flags);
1686
1687         for (i = 0; i < FTRACE_HASHSIZE; i++) {
1688                 INIT_HLIST_HEAD(&temp_list);
1689                 head = &ftrace_hash[i];
1690
1691                 /* all CPUS are stopped, we are safe to modify code */
1692                 hlist_for_each_entry_safe(rec, t, n, head, node) {
1693                         if (rec->flags & FTRACE_FL_FREE)
1694                                 continue;
1695
1696                         if ((rec->ip >= start) && (rec->ip < end))
1697                                 ftrace_free_rec(rec);
1698                 }
1699         }
1700
1701         ftrace_hash_unlock(flags);
1702
1703         per_cpu(ftrace_shutdown_disable_cpu, cpu)--;
1704         preempt_enable_notrace();
1705
1706 }
1707
1708 static int ftraced(void *ignore)
1709 {
1710         unsigned long usecs;
1711
1712         while (!kthread_should_stop()) {
1713
1714                 set_current_state(TASK_INTERRUPTIBLE);
1715
1716                 /* check once a second */
1717                 schedule_timeout(HZ);
1718
1719                 if (unlikely(ftrace_disabled))
1720                         continue;
1721
1722                 mutex_lock(&ftrace_sysctl_lock);
1723                 mutex_lock(&ftraced_lock);
1724                 if (!ftraced_suspend && !ftraced_stop &&
1725                     ftrace_update_code()) {
1726                         usecs = nsecs_to_usecs(ftrace_update_time);
1727                         if (ftrace_update_tot_cnt > 100000) {
1728                                 ftrace_update_tot_cnt = 0;
1729                                 pr_info("hm, dftrace overflow: %lu change%s"
1730                                         " (%lu total) in %lu usec%s\n",
1731                                         ftrace_update_cnt,
1732                                         ftrace_update_cnt != 1 ? "s" : "",
1733                                         ftrace_update_tot_cnt,
1734                                         usecs, usecs != 1 ? "s" : "");
1735                                 FTRACE_WARN_ON_ONCE(1);
1736                         }
1737                 }
1738                 mutex_unlock(&ftraced_lock);
1739                 mutex_unlock(&ftrace_sysctl_lock);
1740
1741                 ftrace_shutdown_replenish();
1742         }
1743         __set_current_state(TASK_RUNNING);
1744         return 0;
1745 }
1746
1747 static int __init ftrace_dynamic_init(void)
1748 {
1749         struct task_struct *p;
1750         unsigned long addr;
1751         int ret;
1752
1753         addr = (unsigned long)ftrace_record_ip;
1754
1755         stop_machine(ftrace_dyn_arch_init, &addr, NULL);
1756
1757         /* ftrace_dyn_arch_init places the return code in addr */
1758         if (addr) {
1759                 ret = (int)addr;
1760                 goto failed;
1761         }
1762
1763         ret = ftrace_dyn_table_alloc(NR_TO_INIT);
1764         if (ret)
1765                 goto failed;
1766
1767         p = kthread_run(ftraced, NULL, "ftraced");
1768         if (IS_ERR(p)) {
1769                 ret = -1;
1770                 goto failed;
1771         }
1772
1773         last_ftrace_enabled = ftrace_enabled = 1;
1774         ftraced_task = p;
1775
1776         return 0;
1777
1778  failed:
1779         ftrace_disabled = 1;
1780         return ret;
1781 }
1782
1783 core_initcall(ftrace_dynamic_init);
1784 #endif /* CONFIG_FTRACE_MCOUNT_RECORD */
1785
1786 #else
1787 # define ftrace_startup()               do { } while (0)
1788 # define ftrace_shutdown()              do { } while (0)
1789 # define ftrace_startup_sysctl()        do { } while (0)
1790 # define ftrace_shutdown_sysctl()       do { } while (0)
1791 #endif /* CONFIG_DYNAMIC_FTRACE */
1792
1793 /**
1794  * ftrace_kill - kill ftrace
1795  *
1796  * This function should be used by panic code. It stops ftrace
1797  * but in a not so nice way. If you need to simply kill ftrace
1798  * from a non-atomic section, use ftrace_kill.
1799  */
1800 void ftrace_kill(void)
1801 {
1802         ftrace_disabled = 1;
1803         ftrace_enabled = 0;
1804 #ifdef CONFIG_DYNAMIC_FTRACE
1805         ftraced_suspend = -1;
1806 #endif
1807         clear_ftrace_function();
1808 }
1809
1810 /**
1811  * register_ftrace_function - register a function for profiling
1812  * @ops - ops structure that holds the function for profiling.
1813  *
1814  * Register a function to be called by all functions in the
1815  * kernel.
1816  *
1817  * Note: @ops->func and all the functions it calls must be labeled
1818  *       with "notrace", otherwise it will go into a
1819  *       recursive loop.
1820  */
1821 int register_ftrace_function(struct ftrace_ops *ops)
1822 {
1823         int ret;
1824
1825         if (unlikely(ftrace_disabled))
1826                 return -1;
1827
1828         mutex_lock(&ftrace_sysctl_lock);
1829         ret = __register_ftrace_function(ops);
1830         ftrace_startup();
1831         mutex_unlock(&ftrace_sysctl_lock);
1832
1833         return ret;
1834 }
1835
1836 /**
1837  * unregister_ftrace_function - unresgister a function for profiling.
1838  * @ops - ops structure that holds the function to unregister
1839  *
1840  * Unregister a function that was added to be called by ftrace profiling.
1841  */
1842 int unregister_ftrace_function(struct ftrace_ops *ops)
1843 {
1844         int ret;
1845
1846         mutex_lock(&ftrace_sysctl_lock);
1847         ret = __unregister_ftrace_function(ops);
1848         ftrace_shutdown();
1849         mutex_unlock(&ftrace_sysctl_lock);
1850
1851         return ret;
1852 }
1853
1854 int
1855 ftrace_enable_sysctl(struct ctl_table *table, int write,
1856                      struct file *file, void __user *buffer, size_t *lenp,
1857                      loff_t *ppos)
1858 {
1859         int ret;
1860
1861         if (unlikely(ftrace_disabled))
1862                 return -ENODEV;
1863
1864         mutex_lock(&ftrace_sysctl_lock);
1865
1866         ret  = proc_dointvec(table, write, file, buffer, lenp, ppos);
1867
1868         if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
1869                 goto out;
1870
1871         last_ftrace_enabled = ftrace_enabled;
1872
1873         if (ftrace_enabled) {
1874
1875                 ftrace_startup_sysctl();
1876
1877                 /* we are starting ftrace again */
1878                 if (ftrace_list != &ftrace_list_end) {
1879                         if (ftrace_list->next == &ftrace_list_end)
1880                                 ftrace_trace_function = ftrace_list->func;
1881                         else
1882                                 ftrace_trace_function = ftrace_list_func;
1883                 }
1884
1885         } else {
1886                 /* stopping ftrace calls (just send to ftrace_stub) */
1887                 ftrace_trace_function = ftrace_stub;
1888
1889                 ftrace_shutdown_sysctl();
1890         }
1891
1892  out:
1893         mutex_unlock(&ftrace_sysctl_lock);
1894         return ret;
1895 }