kernel/trace/ftrace.c

   1 /*
   2  * Infrastructure for profiling code inserted by 'gcc -pg'.
   3  *
   4  * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
   5  * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
   6  *
   7  * Originally ported from the -rt patch by:
   8  *   Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
   9  *
  10  * Based on code in the latency_tracer, that is:
  11  *
  12  *  Copyright (C) 2004-2006 Ingo Molnar
  13  *  Copyright (C) 2004 William Lee Irwin III
  14  */
  15
  16 #include <linux/stop_machine.h>
  17 #include <linux/clocksource.h>
  18 #include <linux/kallsyms.h>
  19 #include <linux/seq_file.h>
  20 #include <linux/debugfs.h>
  21 #include <linux/hardirq.h>
  22 #include <linux/kthread.h>
  23 #include <linux/uaccess.h>
  24 #include <linux/kprobes.h>
  25 #include <linux/ftrace.h>
  26 #include <linux/sysctl.h>
  27 #include <linux/ctype.h>
  28 #include <linux/list.h>
  29
  30 #include <asm/ftrace.h>
  31
  32 #include "trace.h"
  33
  34 #define FTRACE_WARN_ON(cond)                    \
  35         do {                                    \
  36                 if (WARN_ON(cond))              \
  37                         ftrace_kill();          \
  38         } while (0)
  39
  40 #define FTRACE_WARN_ON_ONCE(cond)               \
  41         do {                                    \
  42                 if (WARN_ON_ONCE(cond))         \
  43                         ftrace_kill();          \
  44         } while (0)
  45
  46 /* ftrace_enabled is a method to turn ftrace on or off */
  47 int ftrace_enabled __read_mostly;
  48 static int last_ftrace_enabled;
  49
  50 /* ftrace_pid_trace >= 0 will only trace threads with this pid */
  51 static int ftrace_pid_trace = -1;
  52
  53 /* Quick disabling of function tracer. */
  54 int function_trace_stop;
  55
  56 /*
  57  * ftrace_disabled is set when an anomaly is discovered.
  58  * ftrace_disabled is much stronger than ftrace_enabled.
  59  */
  60 static int ftrace_disabled __read_mostly;
  61
  62 static DEFINE_SPINLOCK(ftrace_lock);
  63 static DEFINE_MUTEX(ftrace_sysctl_lock);
  64 static DEFINE_MUTEX(ftrace_start_lock);
  65
  66 static struct ftrace_ops ftrace_list_end __read_mostly =
  67 {
  68         .func = ftrace_stub,
  69 };
  70
  71 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
  72 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
  73 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
  74 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
  75
  76 static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
  77 {
  78         struct ftrace_ops *op = ftrace_list;
  79
  80         /* in case someone actually ports this to alpha! */
  81         read_barrier_depends();
  82
  83         while (op != &ftrace_list_end) {
  84                 /* silly alpha */
  85                 read_barrier_depends();
  86                 op->func(ip, parent_ip);
  87                 op = op->next;
  88         };
  89 }
  90
  91 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
  92 {
  93         if (current->pid != ftrace_pid_trace)
  94                 return;
  95
  96         ftrace_pid_function(ip, parent_ip);
  97 }
  98
  99 static void set_ftrace_pid_function(ftrace_func_t func)
 100 {
 101         /* do not set ftrace_pid_function to itself! */
 102         if (func != ftrace_pid_func)
 103                 ftrace_pid_function = func;
 104 }
 105
 106 /**
 107  * clear_ftrace_function - reset the ftrace function
 108  *
 109  * This NULLs the ftrace function and in essence stops
 110  * tracing.  There may be lag
 111  */
 112 void clear_ftrace_function(void)
 113 {
 114         ftrace_trace_function = ftrace_stub;
 115         __ftrace_trace_function = ftrace_stub;
 116         ftrace_pid_function = ftrace_stub;
 117 }
 118
 119 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 120 /*
 121  * For those archs that do not test ftrace_trace_stop in their
 122  * mcount call site, we need to do it from C.
 123  */
 124 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
 125 {
 126         if (function_trace_stop)
 127                 return;
 128
 129         __ftrace_trace_function(ip, parent_ip);
 130 }
 131 #endif
 132
 133 static int __register_ftrace_function(struct ftrace_ops *ops)
 134 {
 135         /* should not be called from interrupt context */
 136         spin_lock(&ftrace_lock);
 137
 138         ops->next = ftrace_list;
 139         /*
 140          * We are entering ops into the ftrace_list but another
 141          * CPU might be walking that list. We need to make sure
 142          * the ops->next pointer is valid before another CPU sees
 143          * the ops pointer included into the ftrace_list.
 144          */
 145         smp_wmb();
 146         ftrace_list = ops;
 147
 148         if (ftrace_enabled) {
 149                 ftrace_func_t func;
 150
 151                 if (ops->next == &ftrace_list_end)
 152                         func = ops->func;
 153                 else
 154                         func = ftrace_list_func;
 155
 156                 if (ftrace_pid_trace >= 0) {
 157                         set_ftrace_pid_function(func);
 158                         func = ftrace_pid_func;
 159                 }
 160
 161                 /*
 162                  * For one func, simply call it directly.
 163                  * For more than one func, call the chain.
 164                  */
 165 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 166                 ftrace_trace_function = func;
 167 #else
 168                 __ftrace_trace_function = func;
 169                 ftrace_trace_function = ftrace_test_stop_func;
 170 #endif
 171         }
 172
 173         spin_unlock(&ftrace_lock);
 174
 175         return 0;
 176 }
 177
 178 static int __unregister_ftrace_function(struct ftrace_ops *ops)
 179 {
 180         struct ftrace_ops **p;
 181         int ret = 0;
 182
 183         /* should not be called from interrupt context */
 184         spin_lock(&ftrace_lock);
 185
 186         /*
 187          * If we are removing the last function, then simply point
 188          * to the ftrace_stub.
 189          */
 190         if (ftrace_list == ops && ops->next == &ftrace_list_end) {
 191                 ftrace_trace_function = ftrace_stub;
 192                 ftrace_list = &ftrace_list_end;
 193                 goto out;
 194         }
 195
 196         for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
 197                 if (*p == ops)
 198                         break;
 199
 200         if (*p != ops) {
 201                 ret = -1;
 202                 goto out;
 203         }
 204
 205         *p = (*p)->next;
 206
 207         if (ftrace_enabled) {
 208                 /* If we only have one func left, then call that directly */
 209                 if (ftrace_list->next == &ftrace_list_end) {
 210                         ftrace_func_t func = ftrace_list->func;
 211
 212                         if (ftrace_pid_trace >= 0) {
 213                                 set_ftrace_pid_function(func);
 214                                 func = ftrace_pid_func;
 215                         }
 216 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 217                         ftrace_trace_function = func;
 218 #else
 219                         __ftrace_trace_function = func;
 220 #endif
 221                 }
 222         }
 223
 224  out:
 225         spin_unlock(&ftrace_lock);
 226
 227         return ret;
 228 }
 229
 230 static void ftrace_update_pid_func(void)
 231 {
 232         ftrace_func_t func;
 233
 234         /* should not be called from interrupt context */
 235         spin_lock(&ftrace_lock);
 236
 237         if (ftrace_trace_function == ftrace_stub)
 238                 goto out;
 239
 240         func = ftrace_trace_function;
 241
 242         if (ftrace_pid_trace >= 0) {
 243                 set_ftrace_pid_function(func);
 244                 func = ftrace_pid_func;
 245         } else {
 246                 if (func == ftrace_pid_func)
 247                         func = ftrace_pid_function;
 248         }
 249
 250 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 251         ftrace_trace_function = func;
 252 #else
 253         __ftrace_trace_function = func;
 254 #endif
 255
 256  out:
 257         spin_unlock(&ftrace_lock);
 258 }
 259
 260 #ifdef CONFIG_DYNAMIC_FTRACE
 261 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
 262 # error Dynamic ftrace depends on MCOUNT_RECORD
 263 #endif
 264
 265 /*
 266  * Since MCOUNT_ADDR may point to mcount itself, we do not want
 267  * to get it confused by reading a reference in the code as we
 268  * are parsing on objcopy output of text. Use a variable for
 269  * it instead.
 270  */
 271 static unsigned long mcount_addr = MCOUNT_ADDR;
 272
 273 enum {
 274         FTRACE_ENABLE_CALLS             = (1 << 0),
 275         FTRACE_DISABLE_CALLS            = (1 << 1),
 276         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 277         FTRACE_ENABLE_MCOUNT            = (1 << 3),
 278         FTRACE_DISABLE_MCOUNT           = (1 << 4),
 279         FTRACE_START_FUNC_RET           = (1 << 5),
 280         FTRACE_STOP_FUNC_RET            = (1 << 6),
 281 };
 282
 283 static int ftrace_filtered;
 284
 285 static LIST_HEAD(ftrace_new_addrs);
 286
 287 static DEFINE_MUTEX(ftrace_regex_lock);
 288
 289 struct ftrace_page {
 290         struct ftrace_page      *next;
 291         unsigned long           index;
 292         struct dyn_ftrace       records[];
 293 };
 294
 295 #define ENTRIES_PER_PAGE \
 296   ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
 297
 298 /* estimate from running different kernels */
 299 #define NR_TO_INIT              10000
 300
 301 static struct ftrace_page       *ftrace_pages_start;
 302 static struct ftrace_page       *ftrace_pages;
 303
 304 static struct dyn_ftrace *ftrace_free_records;
 305
 306
 307 #ifdef CONFIG_KPROBES
 308
 309 static int frozen_record_count;
 310
 311 static inline void freeze_record(struct dyn_ftrace *rec)
 312 {
 313         if (!(rec->flags & FTRACE_FL_FROZEN)) {
 314                 rec->flags |= FTRACE_FL_FROZEN;
 315                 frozen_record_count++;
 316         }
 317 }
 318
 319 static inline void unfreeze_record(struct dyn_ftrace *rec)
 320 {
 321         if (rec->flags & FTRACE_FL_FROZEN) {
 322                 rec->flags &= ~FTRACE_FL_FROZEN;
 323                 frozen_record_count--;
 324         }
 325 }
 326
 327 static inline int record_frozen(struct dyn_ftrace *rec)
 328 {
 329         return rec->flags & FTRACE_FL_FROZEN;
 330 }
 331 #else
 332 # define freeze_record(rec)                     ({ 0; })
 333 # define unfreeze_record(rec)                   ({ 0; })
 334 # define record_frozen(rec)                     ({ 0; })
 335 #endif /* CONFIG_KPROBES */
 336
 337 static void ftrace_free_rec(struct dyn_ftrace *rec)
 338 {
 339         rec->ip = (unsigned long)ftrace_free_records;
 340         ftrace_free_records = rec;
 341         rec->flags |= FTRACE_FL_FREE;
 342 }
 343
 344 void ftrace_release(void *start, unsigned long size)
 345 {
 346         struct dyn_ftrace *rec;
 347         struct ftrace_page *pg;
 348         unsigned long s = (unsigned long)start;
 349         unsigned long e = s + size;
 350         int i;
 351
 352         if (ftrace_disabled || !start)
 353                 return;
 354
 355         /* should not be called from interrupt context */
 356         spin_lock(&ftrace_lock);
 357
 358         for (pg = ftrace_pages_start; pg; pg = pg->next) {
 359                 for (i = 0; i < pg->index; i++) {
 360                         rec = &pg->records[i];
 361
 362                         if ((rec->ip >= s) && (rec->ip < e))
 363                                 ftrace_free_rec(rec);
 364                 }
 365         }
 366         spin_unlock(&ftrace_lock);
 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                         /* allocate another page */
 391                         ftrace_pages->next =
 392                                 (void *)get_zeroed_page(GFP_KERNEL);
 393                         if (!ftrace_pages->next)
 394                                 return NULL;
 395                 }
 396                 ftrace_pages = ftrace_pages->next;
 397         }
 398
 399         return &ftrace_pages->records[ftrace_pages->index++];
 400 }
 401
 402 static struct dyn_ftrace *
 403 ftrace_record_ip(unsigned long ip)
 404 {
 405         struct dyn_ftrace *rec;
 406
 407         if (ftrace_disabled)
 408                 return NULL;
 409
 410         rec = ftrace_alloc_dyn_node(ip);
 411         if (!rec)
 412                 return NULL;
 413
 414         rec->ip = ip;
 415
 416         list_add(&rec->list, &ftrace_new_addrs);
 417
 418         return rec;
 419 }
 420
 421 static void print_ip_ins(const char *fmt, unsigned char *p)
 422 {
 423         int i;
 424
 425         printk(KERN_CONT "%s", fmt);
 426
 427         for (i = 0; i < MCOUNT_INSN_SIZE; i++)
 428                 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
 429 }
 430
 431 static void ftrace_bug(int failed, unsigned long ip)
 432 {
 433         switch (failed) {
 434         case -EFAULT:
 435                 FTRACE_WARN_ON_ONCE(1);
 436                 pr_info("ftrace faulted on modifying ");
 437                 print_ip_sym(ip);
 438                 break;
 439         case -EINVAL:
 440                 FTRACE_WARN_ON_ONCE(1);
 441                 pr_info("ftrace failed to modify ");
 442                 print_ip_sym(ip);
 443                 print_ip_ins(" actual: ", (unsigned char *)ip);
 444                 printk(KERN_CONT "\n");
 445                 break;
 446         case -EPERM:
 447                 FTRACE_WARN_ON_ONCE(1);
 448                 pr_info("ftrace faulted on writing ");
 449                 print_ip_sym(ip);
 450                 break;
 451         default:
 452                 FTRACE_WARN_ON_ONCE(1);
 453                 pr_info("ftrace faulted on unknown error ");
 454                 print_ip_sym(ip);
 455         }
 456 }
 457
 458
 459 static int
 460 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
 461 {
 462         unsigned long ip, fl;
 463         unsigned long ftrace_addr;
 464
 465         ftrace_addr = (unsigned long)ftrace_caller;
 466
 467         ip = rec->ip;
 468
 469         /*
 470          * If this record is not to be traced and
 471          * it is not enabled then do nothing.
 472          *
 473          * If this record is not to be traced and
 474          * it is enabled then disabled it.
 475          *
 476          */
 477         if (rec->flags & FTRACE_FL_NOTRACE) {
 478                 if (rec->flags & FTRACE_FL_ENABLED)
 479                         rec->flags &= ~FTRACE_FL_ENABLED;
 480                 else
 481                         return 0;
 482
 483         } else if (ftrace_filtered && enable) {
 484                 /*
 485                  * Filtering is on:
 486                  */
 487
 488                 fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED);
 489
 490                 /* Record is filtered and enabled, do nothing */
 491                 if (fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED))
 492                         return 0;
 493
 494                 /* Record is not filtered and is not enabled do nothing */
 495                 if (!fl)
 496                         return 0;
 497
 498                 /* Record is not filtered but enabled, disable it */
 499                 if (fl == FTRACE_FL_ENABLED)
 500                         rec->flags &= ~FTRACE_FL_ENABLED;
 501                 else
 502                 /* Otherwise record is filtered but not enabled, enable it */
 503                         rec->flags |= FTRACE_FL_ENABLED;
 504         } else {
 505                 /* Disable or not filtered */
 506
 507                 if (enable) {
 508                         /* if record is enabled, do nothing */
 509                         if (rec->flags & FTRACE_FL_ENABLED)
 510                                 return 0;
 511
 512                         rec->flags |= FTRACE_FL_ENABLED;
 513
 514                 } else {
 515
 516                         /* if record is not enabled do nothing */
 517                         if (!(rec->flags & FTRACE_FL_ENABLED))
 518                                 return 0;
 519
 520                         rec->flags &= ~FTRACE_FL_ENABLED;
 521                 }
 522         }
 523
 524         if (rec->flags & FTRACE_FL_ENABLED)
 525                 return ftrace_make_call(rec, ftrace_addr);
 526         else
 527                 return ftrace_make_nop(NULL, rec, ftrace_addr);
 528 }
 529
 530 static void ftrace_replace_code(int enable)
 531 {
 532         int i, failed;
 533         struct dyn_ftrace *rec;
 534         struct ftrace_page *pg;
 535
 536         for (pg = ftrace_pages_start; pg; pg = pg->next) {
 537                 for (i = 0; i < pg->index; i++) {
 538                         rec = &pg->records[i];
 539
 540                         /*
 541                          * Skip over free records and records that have
 542                          * failed.
 543                          */
 544                         if (rec->flags & FTRACE_FL_FREE ||
 545                             rec->flags & FTRACE_FL_FAILED)
 546                                 continue;
 547
 548                         /* ignore updates to this record's mcount site */
 549                         if (get_kprobe((void *)rec->ip)) {
 550                                 freeze_record(rec);
 551                                 continue;
 552                         } else {
 553                                 unfreeze_record(rec);
 554                         }
 555
 556                         failed = __ftrace_replace_code(rec, enable);
 557                         if (failed && (rec->flags & FTRACE_FL_CONVERTED)) {
 558                                 rec->flags |= FTRACE_FL_FAILED;
 559                                 if ((system_state == SYSTEM_BOOTING) ||
 560                                     !core_kernel_text(rec->ip)) {
 561                                         ftrace_free_rec(rec);
 562                                 } else
 563                                         ftrace_bug(failed, rec->ip);
 564                         }
 565                 }
 566         }
 567 }
 568
 569 static int
 570 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
 571 {
 572         unsigned long ip;
 573         int ret;
 574
 575         ip = rec->ip;
 576
 577         ret = ftrace_make_nop(mod, rec, mcount_addr);
 578         if (ret) {
 579                 ftrace_bug(ret, ip);
 580                 rec->flags |= FTRACE_FL_FAILED;
 581                 return 0;
 582         }
 583         return 1;
 584 }
 585
 586 static int __ftrace_modify_code(void *data)
 587 {
 588         int *command = data;
 589
 590         if (*command & FTRACE_ENABLE_CALLS)
 591                 ftrace_replace_code(1);
 592         else if (*command & FTRACE_DISABLE_CALLS)
 593                 ftrace_replace_code(0);
 594
 595         if (*command & FTRACE_UPDATE_TRACE_FUNC)
 596                 ftrace_update_ftrace_func(ftrace_trace_function);
 597
 598         if (*command & FTRACE_START_FUNC_RET)
 599                 ftrace_enable_ftrace_graph_caller();
 600         else if (*command & FTRACE_STOP_FUNC_RET)
 601                 ftrace_disable_ftrace_graph_caller();
 602
 603         return 0;
 604 }
 605
 606 static void ftrace_run_update_code(int command)
 607 {
 608         stop_machine(__ftrace_modify_code, &command, NULL);
 609 }
 610
 611 static ftrace_func_t saved_ftrace_func;
 612 static int ftrace_start_up;
 613
 614 static void ftrace_startup_enable(int command)
 615 {
 616         if (saved_ftrace_func != ftrace_trace_function) {
 617                 saved_ftrace_func = ftrace_trace_function;
 618                 command |= FTRACE_UPDATE_TRACE_FUNC;
 619         }
 620
 621         if (!command || !ftrace_enabled)
 622                 return;
 623
 624         ftrace_run_update_code(command);
 625 }
 626
 627 static void ftrace_startup(int command)
 628 {
 629         if (unlikely(ftrace_disabled))
 630                 return;
 631
 632         mutex_lock(&ftrace_start_lock);
 633         ftrace_start_up++;
 634         command |= FTRACE_ENABLE_CALLS;
 635
 636         ftrace_startup_enable(command);
 637
 638         mutex_unlock(&ftrace_start_lock);
 639 }
 640
 641 static void ftrace_shutdown(int command)
 642 {
 643         if (unlikely(ftrace_disabled))
 644                 return;
 645
 646         mutex_lock(&ftrace_start_lock);
 647         ftrace_start_up--;
 648         if (!ftrace_start_up)
 649                 command |= FTRACE_DISABLE_CALLS;
 650
 651         if (saved_ftrace_func != ftrace_trace_function) {
 652                 saved_ftrace_func = ftrace_trace_function;
 653                 command |= FTRACE_UPDATE_TRACE_FUNC;
 654         }
 655
 656         if (!command || !ftrace_enabled)
 657                 goto out;
 658
 659         ftrace_run_update_code(command);
 660  out:
 661         mutex_unlock(&ftrace_start_lock);
 662 }
 663
 664 static void ftrace_startup_sysctl(void)
 665 {
 666         int command = FTRACE_ENABLE_MCOUNT;
 667
 668         if (unlikely(ftrace_disabled))
 669                 return;
 670
 671         mutex_lock(&ftrace_start_lock);
 672         /* Force update next time */
 673         saved_ftrace_func = NULL;
 674         /* ftrace_start_up is true if we want ftrace running */
 675         if (ftrace_start_up)
 676                 command |= FTRACE_ENABLE_CALLS;
 677
 678         ftrace_run_update_code(command);
 679         mutex_unlock(&ftrace_start_lock);
 680 }
 681
 682 static void ftrace_shutdown_sysctl(void)
 683 {
 684         int command = FTRACE_DISABLE_MCOUNT;
 685
 686         if (unlikely(ftrace_disabled))
 687                 return;
 688
 689         mutex_lock(&ftrace_start_lock);
 690         /* ftrace_start_up is true if ftrace is running */
 691         if (ftrace_start_up)
 692                 command |= FTRACE_DISABLE_CALLS;
 693
 694         ftrace_run_update_code(command);
 695         mutex_unlock(&ftrace_start_lock);
 696 }
 697
 698 static cycle_t          ftrace_update_time;
 699 static unsigned long    ftrace_update_cnt;
 700 unsigned long           ftrace_update_tot_cnt;
 701
 702 static int ftrace_update_code(struct module *mod)
 703 {
 704         struct dyn_ftrace *p, *t;
 705         cycle_t start, stop;
 706
 707         start = ftrace_now(raw_smp_processor_id());
 708         ftrace_update_cnt = 0;
 709
 710         list_for_each_entry_safe(p, t, &ftrace_new_addrs, list) {
 711
 712                 /* If something went wrong, bail without enabling anything */
 713                 if (unlikely(ftrace_disabled))
 714                         return -1;
 715
 716                 list_del_init(&p->list);
 717
 718                 /* convert record (i.e, patch mcount-call with NOP) */
 719                 if (ftrace_code_disable(mod, p)) {
 720                         p->flags |= FTRACE_FL_CONVERTED;
 721                         ftrace_update_cnt++;
 722                 } else
 723                         ftrace_free_rec(p);
 724         }
 725
 726         stop = ftrace_now(raw_smp_processor_id());
 727         ftrace_update_time = stop - start;
 728         ftrace_update_tot_cnt += ftrace_update_cnt;
 729
 730         return 0;
 731 }
 732
 733 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
 734 {
 735         struct ftrace_page *pg;
 736         int cnt;
 737         int i;
 738
 739         /* allocate a few pages */
 740         ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
 741         if (!ftrace_pages_start)
 742                 return -1;
 743
 744         /*
 745          * Allocate a few more pages.
 746          *
 747          * TODO: have some parser search vmlinux before
 748          *   final linking to find all calls to ftrace.
 749          *   Then we can:
 750          *    a) know how many pages to allocate.
 751          *     and/or
 752          *    b) set up the table then.
 753          *
 754          *  The dynamic code is still necessary for
 755          *  modules.
 756          */
 757
 758         pg = ftrace_pages = ftrace_pages_start;
 759
 760         cnt = num_to_init / ENTRIES_PER_PAGE;
 761         pr_info("ftrace: allocating %ld entries in %d pages\n",
 762                 num_to_init, cnt + 1);
 763
 764         for (i = 0; i < cnt; i++) {
 765                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
 766
 767                 /* If we fail, we'll try later anyway */
 768                 if (!pg->next)
 769                         break;
 770
 771                 pg = pg->next;
 772         }
 773
 774         return 0;
 775 }
 776
 777 enum {
 778         FTRACE_ITER_FILTER      = (1 << 0),
 779         FTRACE_ITER_CONT        = (1 << 1),
 780         FTRACE_ITER_NOTRACE     = (1 << 2),
 781         FTRACE_ITER_FAILURES    = (1 << 3),
 782 };
 783
 784 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
 785
 786 struct ftrace_iterator {
 787         struct ftrace_page      *pg;
 788         unsigned                idx;
 789         unsigned                flags;
 790         unsigned char           buffer[FTRACE_BUFF_MAX+1];
 791         unsigned                buffer_idx;
 792         unsigned                filtered;
 793 };
 794
 795 static void *
 796 t_next(struct seq_file *m, void *v, loff_t *pos)
 797 {
 798         struct ftrace_iterator *iter = m->private;
 799         struct dyn_ftrace *rec = NULL;
 800
 801         (*pos)++;
 802
 803         /* should not be called from interrupt context */
 804         spin_lock(&ftrace_lock);
 805  retry:
 806         if (iter->idx >= iter->pg->index) {
 807                 if (iter->pg->next) {
 808                         iter->pg = iter->pg->next;
 809                         iter->idx = 0;
 810                         goto retry;
 811                 } else {
 812                         iter->idx = -1;
 813                 }
 814         } else {
 815                 rec = &iter->pg->records[iter->idx++];
 816                 if ((rec->flags & FTRACE_FL_FREE) ||
 817
 818                     (!(iter->flags & FTRACE_ITER_FAILURES) &&
 819                      (rec->flags & FTRACE_FL_FAILED)) ||
 820
 821                     ((iter->flags & FTRACE_ITER_FAILURES) &&
 822                      !(rec->flags & FTRACE_FL_FAILED)) ||
 823
 824                     ((iter->flags & FTRACE_ITER_FILTER) &&
 825                      !(rec->flags & FTRACE_FL_FILTER)) ||
 826
 827                     ((iter->flags & FTRACE_ITER_NOTRACE) &&
 828                      !(rec->flags & FTRACE_FL_NOTRACE))) {
 829                         rec = NULL;
 830                         goto retry;
 831                 }
 832         }
 833         spin_unlock(&ftrace_lock);
 834
 835         return rec;
 836 }
 837
 838 static void *t_start(struct seq_file *m, loff_t *pos)
 839 {
 840         struct ftrace_iterator *iter = m->private;
 841         void *p = NULL;
 842
 843         if (*pos > 0) {
 844                 if (iter->idx < 0)
 845                         return p;
 846                 (*pos)--;
 847                 iter->idx--;
 848         }
 849
 850         p = t_next(m, p, pos);
 851
 852         return p;
 853 }
 854
 855 static void t_stop(struct seq_file *m, void *p)
 856 {
 857 }
 858
 859 static int t_show(struct seq_file *m, void *v)
 860 {
 861         struct dyn_ftrace *rec = v;
 862         char str[KSYM_SYMBOL_LEN];
 863
 864         if (!rec)
 865                 return 0;
 866
 867         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 868
 869         seq_printf(m, "%s\n", str);
 870
 871         return 0;
 872 }
 873
 874 static struct seq_operations show_ftrace_seq_ops = {
 875         .start = t_start,
 876         .next = t_next,
 877         .stop = t_stop,
 878         .show = t_show,
 879 };
 880
 881 static int
 882 ftrace_avail_open(struct inode *inode, struct file *file)
 883 {
 884         struct ftrace_iterator *iter;
 885         int ret;
 886
 887         if (unlikely(ftrace_disabled))
 888                 return -ENODEV;
 889
 890         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
 891         if (!iter)
 892                 return -ENOMEM;
 893
 894         iter->pg = ftrace_pages_start;
 895
 896         ret = seq_open(file, &show_ftrace_seq_ops);
 897         if (!ret) {
 898                 struct seq_file *m = file->private_data;
 899
 900                 m->private = iter;
 901         } else {
 902                 kfree(iter);
 903         }
 904
 905         return ret;
 906 }
 907
 908 int ftrace_avail_release(struct inode *inode, struct file *file)
 909 {
 910         struct seq_file *m = (struct seq_file *)file->private_data;
 911         struct ftrace_iterator *iter = m->private;
 912
 913         seq_release(inode, file);
 914         kfree(iter);
 915
 916         return 0;
 917 }
 918
 919 static int
 920 ftrace_failures_open(struct inode *inode, struct file *file)
 921 {
 922         int ret;
 923         struct seq_file *m;
 924         struct ftrace_iterator *iter;
 925
 926         ret = ftrace_avail_open(inode, file);
 927         if (!ret) {
 928                 m = (struct seq_file *)file->private_data;
 929                 iter = (struct ftrace_iterator *)m->private;
 930                 iter->flags = FTRACE_ITER_FAILURES;
 931         }
 932
 933         return ret;
 934 }
 935
 936
 937 static void ftrace_filter_reset(int enable)
 938 {
 939         struct ftrace_page *pg;
 940         struct dyn_ftrace *rec;
 941         unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
 942         unsigned i;
 943
 944         /* should not be called from interrupt context */
 945         spin_lock(&ftrace_lock);
 946         if (enable)
 947                 ftrace_filtered = 0;
 948         pg = ftrace_pages_start;
 949         while (pg) {
 950                 for (i = 0; i < pg->index; i++) {
 951                         rec = &pg->records[i];
 952                         if (rec->flags & FTRACE_FL_FAILED)
 953                                 continue;
 954                         rec->flags &= ~type;
 955                 }
 956                 pg = pg->next;
 957         }
 958         spin_unlock(&ftrace_lock);
 959 }
 960
 961 static int
 962 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
 963 {
 964         struct ftrace_iterator *iter;
 965         int ret = 0;
 966
 967         if (unlikely(ftrace_disabled))
 968                 return -ENODEV;
 969
 970         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
 971         if (!iter)
 972                 return -ENOMEM;
 973
 974         mutex_lock(&ftrace_regex_lock);
 975         if ((file->f_mode & FMODE_WRITE) &&
 976             !(file->f_flags & O_APPEND))
 977                 ftrace_filter_reset(enable);
 978
 979         if (file->f_mode & FMODE_READ) {
 980                 iter->pg = ftrace_pages_start;
 981                 iter->flags = enable ? FTRACE_ITER_FILTER :
 982                         FTRACE_ITER_NOTRACE;
 983
 984                 ret = seq_open(file, &show_ftrace_seq_ops);
 985                 if (!ret) {
 986                         struct seq_file *m = file->private_data;
 987                         m->private = iter;
 988                 } else
 989                         kfree(iter);
 990         } else
 991                 file->private_data = iter;
 992         mutex_unlock(&ftrace_regex_lock);
 993
 994         return ret;
 995 }
 996
 997 static int
 998 ftrace_filter_open(struct inode *inode, struct file *file)
 999 {
1000         return ftrace_regex_open(inode, file, 1);
1001 }
1002
1003 static int
1004 ftrace_notrace_open(struct inode *inode, struct file *file)
1005 {
1006         return ftrace_regex_open(inode, file, 0);
1007 }
1008
1009 static ssize_t
1010 ftrace_regex_read(struct file *file, char __user *ubuf,
1011                        size_t cnt, loff_t *ppos)
1012 {
1013         if (file->f_mode & FMODE_READ)
1014                 return seq_read(file, ubuf, cnt, ppos);
1015         else
1016                 return -EPERM;
1017 }
1018
1019 static loff_t
1020 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1021 {
1022         loff_t ret;
1023
1024         if (file->f_mode & FMODE_READ)
1025                 ret = seq_lseek(file, offset, origin);
1026         else
1027                 file->f_pos = ret = 1;
1028
1029         return ret;
1030 }
1031
1032 enum {
1033         MATCH_FULL,
1034         MATCH_FRONT_ONLY,
1035         MATCH_MIDDLE_ONLY,
1036         MATCH_END_ONLY,
1037 };
1038
1039 static void
1040 ftrace_match(unsigned char *buff, int len, int enable)
1041 {
1042         char str[KSYM_SYMBOL_LEN];
1043         char *search = NULL;
1044         struct ftrace_page *pg;
1045         struct dyn_ftrace *rec;
1046         int type = MATCH_FULL;
1047         unsigned long flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1048         unsigned i, match = 0, search_len = 0;
1049
1050         for (i = 0; i < len; i++) {
1051                 if (buff[i] == '*') {
1052                         if (!i) {
1053                                 search = buff + i + 1;
1054                                 type = MATCH_END_ONLY;
1055                                 search_len = len - (i + 1);
1056                         } else {
1057                                 if (type == MATCH_END_ONLY) {
1058                                         type = MATCH_MIDDLE_ONLY;
1059                                 } else {
1060                                         match = i;
1061                                         type = MATCH_FRONT_ONLY;
1062                                 }
1063                                 buff[i] = 0;
1064                                 break;
1065                         }
1066                 }
1067         }
1068
1069         /* should not be called from interrupt context */
1070         spin_lock(&ftrace_lock);
1071         if (enable)
1072                 ftrace_filtered = 1;
1073         pg = ftrace_pages_start;
1074         while (pg) {
1075                 for (i = 0; i < pg->index; i++) {
1076                         int matched = 0;
1077                         char *ptr;
1078
1079                         rec = &pg->records[i];
1080                         if (rec->flags & FTRACE_FL_FAILED)
1081                                 continue;
1082                         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1083                         switch (type) {
1084                         case MATCH_FULL:
1085                                 if (strcmp(str, buff) == 0)
1086                                         matched = 1;
1087                                 break;
1088                         case MATCH_FRONT_ONLY:
1089                                 if (memcmp(str, buff, match) == 0)
1090                                         matched = 1;
1091                                 break;
1092                         case MATCH_MIDDLE_ONLY:
1093                                 if (strstr(str, search))
1094                                         matched = 1;
1095                                 break;
1096                         case MATCH_END_ONLY:
1097                                 ptr = strstr(str, search);
1098                                 if (ptr && (ptr[search_len] == 0))
1099                                         matched = 1;
1100                                 break;
1101                         }
1102                         if (matched)
1103                                 rec->flags |= flag;
1104                 }
1105                 pg = pg->next;
1106         }
1107         spin_unlock(&ftrace_lock);
1108 }
1109
1110 static ssize_t
1111 ftrace_regex_write(struct file *file, const char __user *ubuf,
1112                    size_t cnt, loff_t *ppos, int enable)
1113 {
1114         struct ftrace_iterator *iter;
1115         char ch;
1116         size_t read = 0;
1117         ssize_t ret;
1118
1119         if (!cnt || cnt < 0)
1120                 return 0;
1121
1122         mutex_lock(&ftrace_regex_lock);
1123
1124         if (file->f_mode & FMODE_READ) {
1125                 struct seq_file *m = file->private_data;
1126                 iter = m->private;
1127         } else
1128                 iter = file->private_data;
1129
1130         if (!*ppos) {
1131                 iter->flags &= ~FTRACE_ITER_CONT;
1132                 iter->buffer_idx = 0;
1133         }
1134
1135         ret = get_user(ch, ubuf++);
1136         if (ret)
1137                 goto out;
1138         read++;
1139         cnt--;
1140
1141         if (!(iter->flags & ~FTRACE_ITER_CONT)) {
1142                 /* skip white space */
1143                 while (cnt && isspace(ch)) {
1144                         ret = get_user(ch, ubuf++);
1145                         if (ret)
1146                                 goto out;
1147                         read++;
1148                         cnt--;
1149                 }
1150
1151                 if (isspace(ch)) {
1152                         file->f_pos += read;
1153                         ret = read;
1154                         goto out;
1155                 }
1156
1157                 iter->buffer_idx = 0;
1158         }
1159
1160         while (cnt && !isspace(ch)) {
1161                 if (iter->buffer_idx < FTRACE_BUFF_MAX)
1162                         iter->buffer[iter->buffer_idx++] = ch;
1163                 else {
1164                         ret = -EINVAL;
1165                         goto out;
1166                 }
1167                 ret = get_user(ch, ubuf++);
1168                 if (ret)
1169                         goto out;
1170                 read++;
1171                 cnt--;
1172         }
1173
1174         if (isspace(ch)) {
1175                 iter->filtered++;
1176                 iter->buffer[iter->buffer_idx] = 0;
1177                 ftrace_match(iter->buffer, iter->buffer_idx, enable);
1178                 iter->buffer_idx = 0;
1179         } else
1180                 iter->flags |= FTRACE_ITER_CONT;
1181
1182
1183         file->f_pos += read;
1184
1185         ret = read;
1186  out:
1187         mutex_unlock(&ftrace_regex_lock);
1188
1189         return ret;
1190 }
1191
1192 static ssize_t
1193 ftrace_filter_write(struct file *file, const char __user *ubuf,
1194                     size_t cnt, loff_t *ppos)
1195 {
1196         return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
1197 }
1198
1199 static ssize_t
1200 ftrace_notrace_write(struct file *file, const char __user *ubuf,
1201                      size_t cnt, loff_t *ppos)
1202 {
1203         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
1204 }
1205
1206 static void
1207 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
1208 {
1209         if (unlikely(ftrace_disabled))
1210                 return;
1211
1212         mutex_lock(&ftrace_regex_lock);
1213         if (reset)
1214                 ftrace_filter_reset(enable);
1215         if (buf)
1216                 ftrace_match(buf, len, enable);
1217         mutex_unlock(&ftrace_regex_lock);
1218 }
1219
1220 /**
1221  * ftrace_set_filter - set a function to filter on in ftrace
1222  * @buf - the string that holds the function filter text.
1223  * @len - the length of the string.
1224  * @reset - non zero to reset all filters before applying this filter.
1225  *
1226  * Filters denote which functions should be enabled when tracing is enabled.
1227  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
1228  */
1229 void ftrace_set_filter(unsigned char *buf, int len, int reset)
1230 {
1231         ftrace_set_regex(buf, len, reset, 1);
1232 }
1233
1234 /**
1235  * ftrace_set_notrace - set a function to not trace in ftrace
1236  * @buf - the string that holds the function notrace text.
1237  * @len - the length of the string.
1238  * @reset - non zero to reset all filters before applying this filter.
1239  *
1240  * Notrace Filters denote which functions should not be enabled when tracing
1241  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
1242  * for tracing.
1243  */
1244 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
1245 {
1246         ftrace_set_regex(buf, len, reset, 0);
1247 }
1248
1249 static int
1250 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
1251 {
1252         struct seq_file *m = (struct seq_file *)file->private_data;
1253         struct ftrace_iterator *iter;
1254
1255         mutex_lock(&ftrace_regex_lock);
1256         if (file->f_mode & FMODE_READ) {
1257                 iter = m->private;
1258
1259                 seq_release(inode, file);
1260         } else
1261                 iter = file->private_data;
1262
1263         if (iter->buffer_idx) {
1264                 iter->filtered++;
1265                 iter->buffer[iter->buffer_idx] = 0;
1266                 ftrace_match(iter->buffer, iter->buffer_idx, enable);
1267         }
1268
1269         mutex_lock(&ftrace_sysctl_lock);
1270         mutex_lock(&ftrace_start_lock);
1271         if (ftrace_start_up && ftrace_enabled)
1272                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
1273         mutex_unlock(&ftrace_start_lock);
1274         mutex_unlock(&ftrace_sysctl_lock);
1275
1276         kfree(iter);
1277         mutex_unlock(&ftrace_regex_lock);
1278         return 0;
1279 }
1280
1281 static int
1282 ftrace_filter_release(struct inode *inode, struct file *file)
1283 {
1284         return ftrace_regex_release(inode, file, 1);
1285 }
1286
1287 static int
1288 ftrace_notrace_release(struct inode *inode, struct file *file)
1289 {
1290         return ftrace_regex_release(inode, file, 0);
1291 }
1292
1293 static struct file_operations ftrace_avail_fops = {
1294         .open = ftrace_avail_open,
1295         .read = seq_read,
1296         .llseek = seq_lseek,
1297         .release = ftrace_avail_release,
1298 };
1299
1300 static struct file_operations ftrace_failures_fops = {
1301         .open = ftrace_failures_open,
1302         .read = seq_read,
1303         .llseek = seq_lseek,
1304         .release = ftrace_avail_release,
1305 };
1306
1307 static struct file_operations ftrace_filter_fops = {
1308         .open = ftrace_filter_open,
1309         .read = ftrace_regex_read,
1310         .write = ftrace_filter_write,
1311         .llseek = ftrace_regex_lseek,
1312         .release = ftrace_filter_release,
1313 };
1314
1315 static struct file_operations ftrace_notrace_fops = {
1316         .open = ftrace_notrace_open,
1317         .read = ftrace_regex_read,
1318         .write = ftrace_notrace_write,
1319         .llseek = ftrace_regex_lseek,
1320         .release = ftrace_notrace_release,
1321 };
1322
1323 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
1324 {
1325         struct dentry *entry;
1326
1327         entry = debugfs_create_file("available_filter_functions", 0444,
1328                                     d_tracer, NULL, &ftrace_avail_fops);
1329         if (!entry)
1330                 pr_warning("Could not create debugfs "
1331                            "'available_filter_functions' entry\n");
1332
1333         entry = debugfs_create_file("failures", 0444,
1334                                     d_tracer, NULL, &ftrace_failures_fops);
1335         if (!entry)
1336                 pr_warning("Could not create debugfs 'failures' entry\n");
1337
1338         entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer,
1339                                     NULL, &ftrace_filter_fops);
1340         if (!entry)
1341                 pr_warning("Could not create debugfs "
1342                            "'set_ftrace_filter' entry\n");
1343
1344         entry = debugfs_create_file("set_ftrace_notrace", 0644, d_tracer,
1345                                     NULL, &ftrace_notrace_fops);
1346         if (!entry)
1347                 pr_warning("Could not create debugfs "
1348                            "'set_ftrace_notrace' entry\n");
1349
1350         return 0;
1351 }
1352
1353 static int ftrace_convert_nops(struct module *mod,
1354                                unsigned long *start,
1355                                unsigned long *end)
1356 {
1357         unsigned long *p;
1358         unsigned long addr;
1359         unsigned long flags;
1360
1361         mutex_lock(&ftrace_start_lock);
1362         p = start;
1363         while (p < end) {
1364                 addr = ftrace_call_adjust(*p++);
1365                 /*
1366                  * Some architecture linkers will pad between
1367                  * the different mcount_loc sections of different
1368                  * object files to satisfy alignments.
1369                  * Skip any NULL pointers.
1370                  */
1371                 if (!addr)
1372                         continue;
1373                 ftrace_record_ip(addr);
1374         }
1375
1376         /* disable interrupts to prevent kstop machine */
1377         local_irq_save(flags);
1378         ftrace_update_code(mod);
1379         local_irq_restore(flags);
1380         mutex_unlock(&ftrace_start_lock);
1381
1382         return 0;
1383 }
1384
1385 void ftrace_init_module(struct module *mod,
1386                         unsigned long *start, unsigned long *end)
1387 {
1388         if (ftrace_disabled || start == end)
1389                 return;
1390         ftrace_convert_nops(mod, start, end);
1391 }
1392
1393 extern unsigned long __start_mcount_loc[];
1394 extern unsigned long __stop_mcount_loc[];
1395
1396 void __init ftrace_init(void)
1397 {
1398         unsigned long count, addr, flags;
1399         int ret;
1400
1401         /* Keep the ftrace pointer to the stub */
1402         addr = (unsigned long)ftrace_stub;
1403
1404         local_irq_save(flags);
1405         ftrace_dyn_arch_init(&addr);
1406         local_irq_restore(flags);
1407
1408         /* ftrace_dyn_arch_init places the return code in addr */
1409         if (addr)
1410                 goto failed;
1411
1412         count = __stop_mcount_loc - __start_mcount_loc;
1413
1414         ret = ftrace_dyn_table_alloc(count);
1415         if (ret)
1416                 goto failed;
1417
1418         last_ftrace_enabled = ftrace_enabled = 1;
1419
1420         ret = ftrace_convert_nops(NULL,
1421                                   __start_mcount_loc,
1422                                   __stop_mcount_loc);
1423
1424         return;
1425  failed:
1426         ftrace_disabled = 1;
1427 }
1428
1429 #else
1430
1431 static int __init ftrace_nodyn_init(void)
1432 {
1433         ftrace_enabled = 1;
1434         return 0;
1435 }
1436 device_initcall(ftrace_nodyn_init);
1437
1438 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
1439 static inline void ftrace_startup_enable(int command) { }
1440 /* Keep as macros so we do not need to define the commands */
1441 # define ftrace_startup(command)        do { } while (0)
1442 # define ftrace_shutdown(command)       do { } while (0)
1443 # define ftrace_startup_sysctl()        do { } while (0)
1444 # define ftrace_shutdown_sysctl()       do { } while (0)
1445 #endif /* CONFIG_DYNAMIC_FTRACE */
1446
1447 static ssize_t
1448 ftrace_pid_read(struct file *file, char __user *ubuf,
1449                        size_t cnt, loff_t *ppos)
1450 {
1451         char buf[64];
1452         int r;
1453
1454         if (ftrace_pid_trace >= 0)
1455                 r = sprintf(buf, "%u\n", ftrace_pid_trace);
1456         else
1457                 r = sprintf(buf, "no pid\n");
1458
1459         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1460 }
1461
1462 static ssize_t
1463 ftrace_pid_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         buf[cnt] = 0;
1477
1478         ret = strict_strtol(buf, 10, &val);
1479         if (ret < 0)
1480                 return ret;
1481
1482         mutex_lock(&ftrace_start_lock);
1483         if (ret < 0) {
1484                 /* disable pid tracing */
1485                 if (ftrace_pid_trace < 0)
1486                         goto out;
1487                 ftrace_pid_trace = -1;
1488
1489         } else {
1490
1491                 if (ftrace_pid_trace == val)
1492                         goto out;
1493
1494                 ftrace_pid_trace = val;
1495         }
1496
1497         /* update the function call */
1498         ftrace_update_pid_func();
1499         ftrace_startup_enable(0);
1500
1501  out:
1502         mutex_unlock(&ftrace_start_lock);
1503
1504         return cnt;
1505 }
1506
1507 static struct file_operations ftrace_pid_fops = {
1508         .read = ftrace_pid_read,
1509         .write = ftrace_pid_write,
1510 };
1511
1512 static __init int ftrace_init_debugfs(void)
1513 {
1514         struct dentry *d_tracer;
1515         struct dentry *entry;
1516
1517         d_tracer = tracing_init_dentry();
1518         if (!d_tracer)
1519                 return 0;
1520
1521         ftrace_init_dyn_debugfs(d_tracer);
1522
1523         entry = debugfs_create_file("set_ftrace_pid", 0644, d_tracer,
1524                                     NULL, &ftrace_pid_fops);
1525         if (!entry)
1526                 pr_warning("Could not create debugfs "
1527                            "'set_ftrace_pid' entry\n");
1528         return 0;
1529 }
1530
1531 fs_initcall(ftrace_init_debugfs);
1532
1533 /**
1534  * ftrace_kill - kill ftrace
1535  *
1536  * This function should be used by panic code. It stops ftrace
1537  * but in a not so nice way. If you need to simply kill ftrace
1538  * from a non-atomic section, use ftrace_kill.
1539  */
1540 void ftrace_kill(void)
1541 {
1542         ftrace_disabled = 1;
1543         ftrace_enabled = 0;
1544         clear_ftrace_function();
1545 }
1546
1547 /**
1548  * register_ftrace_function - register a function for profiling
1549  * @ops - ops structure that holds the function for profiling.
1550  *
1551  * Register a function to be called by all functions in the
1552  * kernel.
1553  *
1554  * Note: @ops->func and all the functions it calls must be labeled
1555  *       with "notrace", otherwise it will go into a
1556  *       recursive loop.
1557  */
1558 int register_ftrace_function(struct ftrace_ops *ops)
1559 {
1560         int ret;
1561
1562         if (unlikely(ftrace_disabled))
1563                 return -1;
1564
1565         mutex_lock(&ftrace_sysctl_lock);
1566
1567         ret = __register_ftrace_function(ops);
1568         ftrace_startup(0);
1569
1570         mutex_unlock(&ftrace_sysctl_lock);
1571         return ret;
1572 }
1573
1574 /**
1575  * unregister_ftrace_function - unresgister a function for profiling.
1576  * @ops - ops structure that holds the function to unregister
1577  *
1578  * Unregister a function that was added to be called by ftrace profiling.
1579  */
1580 int unregister_ftrace_function(struct ftrace_ops *ops)
1581 {
1582         int ret;
1583
1584         mutex_lock(&ftrace_sysctl_lock);
1585         ret = __unregister_ftrace_function(ops);
1586         ftrace_shutdown(0);
1587         mutex_unlock(&ftrace_sysctl_lock);
1588
1589         return ret;
1590 }
1591
1592 int
1593 ftrace_enable_sysctl(struct ctl_table *table, int write,
1594                      struct file *file, void __user *buffer, size_t *lenp,
1595                      loff_t *ppos)
1596 {
1597         int ret;
1598
1599         if (unlikely(ftrace_disabled))
1600                 return -ENODEV;
1601
1602         mutex_lock(&ftrace_sysctl_lock);
1603
1604         ret  = proc_dointvec(table, write, file, buffer, lenp, ppos);
1605
1606         if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
1607                 goto out;
1608
1609         last_ftrace_enabled = ftrace_enabled;
1610
1611         if (ftrace_enabled) {
1612
1613                 ftrace_startup_sysctl();
1614
1615                 /* we are starting ftrace again */
1616                 if (ftrace_list != &ftrace_list_end) {
1617                         if (ftrace_list->next == &ftrace_list_end)
1618                                 ftrace_trace_function = ftrace_list->func;
1619                         else
1620                                 ftrace_trace_function = ftrace_list_func;
1621                 }
1622
1623         } else {
1624                 /* stopping ftrace calls (just send to ftrace_stub) */
1625                 ftrace_trace_function = ftrace_stub;
1626
1627                 ftrace_shutdown_sysctl();
1628         }
1629
1630  out:
1631         mutex_unlock(&ftrace_sysctl_lock);
1632         return ret;
1633 }
1634
1635 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1636
1637 static atomic_t ftrace_graph_active;
1638
1639 /* The callbacks that hook a function */
1640 trace_func_graph_ret_t ftrace_graph_return =
1641                         (trace_func_graph_ret_t)ftrace_stub;
1642 trace_func_graph_ent_t ftrace_graph_entry =
1643                         (trace_func_graph_ent_t)ftrace_stub;
1644
1645 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
1646 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
1647 {
1648         int i;
1649         int ret = 0;
1650         unsigned long flags;
1651         int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
1652         struct task_struct *g, *t;
1653
1654         for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
1655                 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
1656                                         * sizeof(struct ftrace_ret_stack),
1657                                         GFP_KERNEL);
1658                 if (!ret_stack_list[i]) {
1659                         start = 0;
1660                         end = i;
1661                         ret = -ENOMEM;
1662                         goto free;
1663                 }
1664         }
1665
1666         read_lock_irqsave(&tasklist_lock, flags);
1667         do_each_thread(g, t) {
1668                 if (start == end) {
1669                         ret = -EAGAIN;
1670                         goto unlock;
1671                 }
1672
1673                 if (t->ret_stack == NULL) {
1674                         t->curr_ret_stack = -1;
1675                         /* Make sure IRQs see the -1 first: */
1676                         barrier();
1677                         t->ret_stack = ret_stack_list[start++];
1678                         atomic_set(&t->trace_overrun, 0);
1679                 }
1680         } while_each_thread(g, t);
1681
1682 unlock:
1683         read_unlock_irqrestore(&tasklist_lock, flags);
1684 free:
1685         for (i = start; i < end; i++)
1686                 kfree(ret_stack_list[i]);
1687         return ret;
1688 }
1689
1690 /* Allocate a return stack for each task */
1691 static int start_graph_tracing(void)
1692 {
1693         struct ftrace_ret_stack **ret_stack_list;
1694         int ret;
1695
1696         ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
1697                                 sizeof(struct ftrace_ret_stack *),
1698                                 GFP_KERNEL);
1699
1700         if (!ret_stack_list)
1701                 return -ENOMEM;
1702
1703         do {
1704                 ret = alloc_retstack_tasklist(ret_stack_list);
1705         } while (ret == -EAGAIN);
1706
1707         kfree(ret_stack_list);
1708         return ret;
1709 }
1710
1711 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
1712                         trace_func_graph_ent_t entryfunc)
1713 {
1714         int ret = 0;
1715
1716         mutex_lock(&ftrace_sysctl_lock);
1717
1718         atomic_inc(&ftrace_graph_active);
1719         ret = start_graph_tracing();
1720         if (ret) {
1721                 atomic_dec(&ftrace_graph_active);
1722                 goto out;
1723         }
1724
1725         ftrace_graph_return = retfunc;
1726         ftrace_graph_entry = entryfunc;
1727
1728         ftrace_startup(FTRACE_START_FUNC_RET);
1729
1730 out:
1731         mutex_unlock(&ftrace_sysctl_lock);
1732         return ret;
1733 }
1734
1735 void unregister_ftrace_graph(void)
1736 {
1737         mutex_lock(&ftrace_sysctl_lock);
1738
1739         atomic_dec(&ftrace_graph_active);
1740         ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
1741         ftrace_graph_entry = (trace_func_graph_ent_t)ftrace_stub;
1742         ftrace_shutdown(FTRACE_STOP_FUNC_RET);
1743
1744         mutex_unlock(&ftrace_sysctl_lock);
1745 }
1746
1747 /* Allocate a return stack for newly created task */
1748 void ftrace_graph_init_task(struct task_struct *t)
1749 {
1750         if (atomic_read(&ftrace_graph_active)) {
1751                 t->ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
1752                                 * sizeof(struct ftrace_ret_stack),
1753                                 GFP_KERNEL);
1754                 if (!t->ret_stack)
1755                         return;
1756                 t->curr_ret_stack = -1;
1757                 atomic_set(&t->trace_overrun, 0);
1758         } else
1759                 t->ret_stack = NULL;
1760 }
1761
1762 void ftrace_graph_exit_task(struct task_struct *t)
1763 {
1764         struct ftrace_ret_stack *ret_stack = t->ret_stack;
1765
1766         t->ret_stack = NULL;
1767         /* NULL must become visible to IRQs before we free it: */
1768         barrier();
1769
1770         kfree(ret_stack);
1771 }
1772 #endif
1773