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/suspend.h>
  21 #include <linux/debugfs.h>
  22 #include <linux/hardirq.h>
  23 #include <linux/kthread.h>
  24 #include <linux/uaccess.h>
  25 #include <linux/kprobes.h>
  26 #include <linux/ftrace.h>
  27 #include <linux/sysctl.h>
  28 #include <linux/ctype.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 /* set when tracing only a pid */
  52 struct pid *ftrace_pid_trace;
  53 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
  54
  55 /* Quick disabling of function tracer. */
  56 int function_trace_stop;
  57
  58 /*
  59  * ftrace_disabled is set when an anomaly is discovered.
  60  * ftrace_disabled is much stronger than ftrace_enabled.
  61  */
  62 static int ftrace_disabled __read_mostly;
  63
  64 static DEFINE_SPINLOCK(ftrace_lock);
  65 static DEFINE_MUTEX(ftrace_sysctl_lock);
  66 static DEFINE_MUTEX(ftrace_start_lock);
  67
  68 static struct ftrace_ops ftrace_list_end __read_mostly =
  69 {
  70         .func = ftrace_stub,
  71 };
  72
  73 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
  74 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
  75 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
  76 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
  77
  78 static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
  79 {
  80         struct ftrace_ops *op = ftrace_list;
  81
  82         /* in case someone actually ports this to alpha! */
  83         read_barrier_depends();
  84
  85         while (op != &ftrace_list_end) {
  86                 /* silly alpha */
  87                 read_barrier_depends();
  88                 op->func(ip, parent_ip);
  89                 op = op->next;
  90         };
  91 }
  92
  93 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
  94 {
  95         if (!test_tsk_trace_trace(current))
  96                 return;
  97
  98         ftrace_pid_function(ip, parent_ip);
  99 }
 100
 101 static void set_ftrace_pid_function(ftrace_func_t func)
 102 {
 103         /* do not set ftrace_pid_function to itself! */
 104         if (func != ftrace_pid_func)
 105                 ftrace_pid_function = func;
 106 }
 107
 108 /**
 109  * clear_ftrace_function - reset the ftrace function
 110  *
 111  * This NULLs the ftrace function and in essence stops
 112  * tracing.  There may be lag
 113  */
 114 void clear_ftrace_function(void)
 115 {
 116         ftrace_trace_function = ftrace_stub;
 117         __ftrace_trace_function = ftrace_stub;
 118         ftrace_pid_function = ftrace_stub;
 119 }
 120
 121 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 122 /*
 123  * For those archs that do not test ftrace_trace_stop in their
 124  * mcount call site, we need to do it from C.
 125  */
 126 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
 127 {
 128         if (function_trace_stop)
 129                 return;
 130
 131         __ftrace_trace_function(ip, parent_ip);
 132 }
 133 #endif
 134
 135 static int __register_ftrace_function(struct ftrace_ops *ops)
 136 {
 137         /* should not be called from interrupt context */
 138         spin_lock(&ftrace_lock);
 139
 140         ops->next = ftrace_list;
 141         /*
 142          * We are entering ops into the ftrace_list but another
 143          * CPU might be walking that list. We need to make sure
 144          * the ops->next pointer is valid before another CPU sees
 145          * the ops pointer included into the ftrace_list.
 146          */
 147         smp_wmb();
 148         ftrace_list = ops;
 149
 150         if (ftrace_enabled) {
 151                 ftrace_func_t func;
 152
 153                 if (ops->next == &ftrace_list_end)
 154                         func = ops->func;
 155                 else
 156                         func = ftrace_list_func;
 157
 158                 if (ftrace_pid_trace) {
 159                         set_ftrace_pid_function(func);
 160                         func = ftrace_pid_func;
 161                 }
 162
 163                 /*
 164                  * For one func, simply call it directly.
 165                  * For more than one func, call the chain.
 166                  */
 167 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 168                 ftrace_trace_function = func;
 169 #else
 170                 __ftrace_trace_function = func;
 171                 ftrace_trace_function = ftrace_test_stop_func;
 172 #endif
 173         }
 174
 175         spin_unlock(&ftrace_lock);
 176
 177         return 0;
 178 }
 179
 180 static int __unregister_ftrace_function(struct ftrace_ops *ops)
 181 {
 182         struct ftrace_ops **p;
 183         int ret = 0;
 184
 185         /* should not be called from interrupt context */
 186         spin_lock(&ftrace_lock);
 187
 188         /*
 189          * If we are removing the last function, then simply point
 190          * to the ftrace_stub.
 191          */
 192         if (ftrace_list == ops && ops->next == &ftrace_list_end) {
 193                 ftrace_trace_function = ftrace_stub;
 194                 ftrace_list = &ftrace_list_end;
 195                 goto out;
 196         }
 197
 198         for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
 199                 if (*p == ops)
 200                         break;
 201
 202         if (*p != ops) {
 203                 ret = -1;
 204                 goto out;
 205         }
 206
 207         *p = (*p)->next;
 208
 209         if (ftrace_enabled) {
 210                 /* If we only have one func left, then call that directly */
 211                 if (ftrace_list->next == &ftrace_list_end) {
 212                         ftrace_func_t func = ftrace_list->func;
 213
 214                         if (ftrace_pid_trace) {
 215                                 set_ftrace_pid_function(func);
 216                                 func = ftrace_pid_func;
 217                         }
 218 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 219                         ftrace_trace_function = func;
 220 #else
 221                         __ftrace_trace_function = func;
 222 #endif
 223                 }
 224         }
 225
 226  out:
 227         spin_unlock(&ftrace_lock);
 228
 229         return ret;
 230 }
 231
 232 static void ftrace_update_pid_func(void)
 233 {
 234         ftrace_func_t func;
 235
 236         /* should not be called from interrupt context */
 237         spin_lock(&ftrace_lock);
 238
 239         if (ftrace_trace_function == ftrace_stub)
 240                 goto out;
 241
 242         func = ftrace_trace_function;
 243
 244         if (ftrace_pid_trace) {
 245                 set_ftrace_pid_function(func);
 246                 func = ftrace_pid_func;
 247         } else {
 248                 if (func == ftrace_pid_func)
 249                         func = ftrace_pid_function;
 250         }
 251
 252 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 253         ftrace_trace_function = func;
 254 #else
 255         __ftrace_trace_function = func;
 256 #endif
 257
 258  out:
 259         spin_unlock(&ftrace_lock);
 260 }
 261
 262 #ifdef CONFIG_DYNAMIC_FTRACE
 263 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
 264 # error Dynamic ftrace depends on MCOUNT_RECORD
 265 #endif
 266
 267 enum {
 268         FTRACE_ENABLE_CALLS             = (1 << 0),
 269         FTRACE_DISABLE_CALLS            = (1 << 1),
 270         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 271         FTRACE_ENABLE_MCOUNT            = (1 << 3),
 272         FTRACE_DISABLE_MCOUNT           = (1 << 4),
 273         FTRACE_START_FUNC_RET           = (1 << 5),
 274         FTRACE_STOP_FUNC_RET            = (1 << 6),
 275 };
 276
 277 static int ftrace_filtered;
 278
 279 static LIST_HEAD(ftrace_new_addrs);
 280
 281 static DEFINE_MUTEX(ftrace_regex_lock);
 282
 283 struct ftrace_page {
 284         struct ftrace_page      *next;
 285         int                     index;
 286         struct dyn_ftrace       records[];
 287 };
 288
 289 #define ENTRIES_PER_PAGE \
 290   ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
 291
 292 /* estimate from running different kernels */
 293 #define NR_TO_INIT              10000
 294
 295 static struct ftrace_page       *ftrace_pages_start;
 296 static struct ftrace_page       *ftrace_pages;
 297
 298 static struct dyn_ftrace *ftrace_free_records;
 299
 300 /*
 301  * This is a double for. Do not use 'break' to break out of the loop,
 302  * you must use a goto.
 303  */
 304 #define do_for_each_ftrace_rec(pg, rec)                                 \
 305         for (pg = ftrace_pages_start; pg; pg = pg->next) {              \
 306                 int _____i;                                             \
 307                 for (_____i = 0; _____i < pg->index; _____i++) {        \
 308                         rec = &pg->records[_____i];
 309
 310 #define while_for_each_ftrace_rec()             \
 311                 }                               \
 312         }
 313
 314 #ifdef CONFIG_KPROBES
 315
 316 static int frozen_record_count;
 317
 318 static inline void freeze_record(struct dyn_ftrace *rec)
 319 {
 320         if (!(rec->flags & FTRACE_FL_FROZEN)) {
 321                 rec->flags |= FTRACE_FL_FROZEN;
 322                 frozen_record_count++;
 323         }
 324 }
 325
 326 static inline void unfreeze_record(struct dyn_ftrace *rec)
 327 {
 328         if (rec->flags & FTRACE_FL_FROZEN) {
 329                 rec->flags &= ~FTRACE_FL_FROZEN;
 330                 frozen_record_count--;
 331         }
 332 }
 333
 334 static inline int record_frozen(struct dyn_ftrace *rec)
 335 {
 336         return rec->flags & FTRACE_FL_FROZEN;
 337 }
 338 #else
 339 # define freeze_record(rec)                     ({ 0; })
 340 # define unfreeze_record(rec)                   ({ 0; })
 341 # define record_frozen(rec)                     ({ 0; })
 342 #endif /* CONFIG_KPROBES */
 343
 344 static void ftrace_free_rec(struct dyn_ftrace *rec)
 345 {
 346         rec->ip = (unsigned long)ftrace_free_records;
 347         ftrace_free_records = rec;
 348         rec->flags |= FTRACE_FL_FREE;
 349 }
 350
 351 void ftrace_release(void *start, unsigned long size)
 352 {
 353         struct dyn_ftrace *rec;
 354         struct ftrace_page *pg;
 355         unsigned long s = (unsigned long)start;
 356         unsigned long e = s + size;
 357
 358         if (ftrace_disabled || !start)
 359                 return;
 360
 361         /* should not be called from interrupt context */
 362         spin_lock(&ftrace_lock);
 363
 364         do_for_each_ftrace_rec(pg, rec) {
 365                 if ((rec->ip >= s) && (rec->ip < e))
 366                         ftrace_free_rec(rec);
 367         } while_for_each_ftrace_rec();
 368
 369         spin_unlock(&ftrace_lock);
 370 }
 371
 372 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
 373 {
 374         struct dyn_ftrace *rec;
 375
 376         /* First check for freed records */
 377         if (ftrace_free_records) {
 378                 rec = ftrace_free_records;
 379
 380                 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
 381                         FTRACE_WARN_ON_ONCE(1);
 382                         ftrace_free_records = NULL;
 383                         return NULL;
 384                 }
 385
 386                 ftrace_free_records = (void *)rec->ip;
 387                 memset(rec, 0, sizeof(*rec));
 388                 return rec;
 389         }
 390
 391         if (ftrace_pages->index == ENTRIES_PER_PAGE) {
 392                 if (!ftrace_pages->next) {
 393                         /* allocate another page */
 394                         ftrace_pages->next =
 395                                 (void *)get_zeroed_page(GFP_KERNEL);
 396                         if (!ftrace_pages->next)
 397                                 return NULL;
 398                 }
 399                 ftrace_pages = ftrace_pages->next;
 400         }
 401
 402         return &ftrace_pages->records[ftrace_pages->index++];
 403 }
 404
 405 static struct dyn_ftrace *
 406 ftrace_record_ip(unsigned long ip)
 407 {
 408         struct dyn_ftrace *rec;
 409
 410         if (ftrace_disabled)
 411                 return NULL;
 412
 413         rec = ftrace_alloc_dyn_node(ip);
 414         if (!rec)
 415                 return NULL;
 416
 417         rec->ip = ip;
 418
 419         list_add(&rec->list, &ftrace_new_addrs);
 420
 421         return rec;
 422 }
 423
 424 static void print_ip_ins(const char *fmt, unsigned char *p)
 425 {
 426         int i;
 427
 428         printk(KERN_CONT "%s", fmt);
 429
 430         for (i = 0; i < MCOUNT_INSN_SIZE; i++)
 431                 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
 432 }
 433
 434 static void ftrace_bug(int failed, unsigned long ip)
 435 {
 436         switch (failed) {
 437         case -EFAULT:
 438                 FTRACE_WARN_ON_ONCE(1);
 439                 pr_info("ftrace faulted on modifying ");
 440                 print_ip_sym(ip);
 441                 break;
 442         case -EINVAL:
 443                 FTRACE_WARN_ON_ONCE(1);
 444                 pr_info("ftrace failed to modify ");
 445                 print_ip_sym(ip);
 446                 print_ip_ins(" actual: ", (unsigned char *)ip);
 447                 printk(KERN_CONT "\n");
 448                 break;
 449         case -EPERM:
 450                 FTRACE_WARN_ON_ONCE(1);
 451                 pr_info("ftrace faulted on writing ");
 452                 print_ip_sym(ip);
 453                 break;
 454         default:
 455                 FTRACE_WARN_ON_ONCE(1);
 456                 pr_info("ftrace faulted on unknown error ");
 457                 print_ip_sym(ip);
 458         }
 459 }
 460
 461
 462 static int
 463 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
 464 {
 465         unsigned long ip, fl;
 466         unsigned long ftrace_addr;
 467
 468         ftrace_addr = (unsigned long)FTRACE_ADDR;
 469
 470         ip = rec->ip;
 471
 472         /*
 473          * If this record is not to be traced and
 474          * it is not enabled then do nothing.
 475          *
 476          * If this record is not to be traced and
 477          * it is enabled then disable it.
 478          *
 479          */
 480         if (rec->flags & FTRACE_FL_NOTRACE) {
 481                 if (rec->flags & FTRACE_FL_ENABLED)
 482                         rec->flags &= ~FTRACE_FL_ENABLED;
 483                 else
 484                         return 0;
 485
 486         } else if (ftrace_filtered && enable) {
 487                 /*
 488                  * Filtering is on:
 489                  */
 490
 491                 fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED);
 492
 493                 /* Record is filtered and enabled, do nothing */
 494                 if (fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED))
 495                         return 0;
 496
 497                 /* Record is not filtered or enabled, do nothing */
 498                 if (!fl)
 499                         return 0;
 500
 501                 /* Record is not filtered but enabled, disable it */
 502                 if (fl == FTRACE_FL_ENABLED)
 503                         rec->flags &= ~FTRACE_FL_ENABLED;
 504                 else
 505                 /* Otherwise record is filtered but not enabled, enable it */
 506                         rec->flags |= FTRACE_FL_ENABLED;
 507         } else {
 508                 /* Disable or not filtered */
 509
 510                 if (enable) {
 511                         /* if record is enabled, do nothing */
 512                         if (rec->flags & FTRACE_FL_ENABLED)
 513                                 return 0;
 514
 515                         rec->flags |= FTRACE_FL_ENABLED;
 516
 517                 } else {
 518
 519                         /* if record is not enabled, do nothing */
 520                         if (!(rec->flags & FTRACE_FL_ENABLED))
 521                                 return 0;
 522
 523                         rec->flags &= ~FTRACE_FL_ENABLED;
 524                 }
 525         }
 526
 527         if (rec->flags & FTRACE_FL_ENABLED)
 528                 return ftrace_make_call(rec, ftrace_addr);
 529         else
 530                 return ftrace_make_nop(NULL, rec, ftrace_addr);
 531 }
 532
 533 static void ftrace_replace_code(int enable)
 534 {
 535         int failed;
 536         struct dyn_ftrace *rec;
 537         struct ftrace_page *pg;
 538
 539         do_for_each_ftrace_rec(pg, rec) {
 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         } while_for_each_ftrace_rec();
 566 }
 567
 568 static int
 569 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
 570 {
 571         unsigned long ip;
 572         int ret;
 573
 574         ip = rec->ip;
 575
 576         ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
 577         if (ret) {
 578                 ftrace_bug(ret, ip);
 579                 rec->flags |= FTRACE_FL_FAILED;
 580                 return 0;
 581         }
 582         return 1;
 583 }
 584
 585 static int __ftrace_modify_code(void *data)
 586 {
 587         int *command = data;
 588
 589         if (*command & FTRACE_ENABLE_CALLS)
 590                 ftrace_replace_code(1);
 591         else if (*command & FTRACE_DISABLE_CALLS)
 592                 ftrace_replace_code(0);
 593
 594         if (*command & FTRACE_UPDATE_TRACE_FUNC)
 595                 ftrace_update_ftrace_func(ftrace_trace_function);
 596
 597         if (*command & FTRACE_START_FUNC_RET)
 598                 ftrace_enable_ftrace_graph_caller();
 599         else if (*command & FTRACE_STOP_FUNC_RET)
 600                 ftrace_disable_ftrace_graph_caller();
 601
 602         return 0;
 603 }
 604
 605 static void ftrace_run_update_code(int command)
 606 {
 607         stop_machine(__ftrace_modify_code, &command, NULL);
 608 }
 609
 610 static ftrace_func_t saved_ftrace_func;
 611 static int ftrace_start_up;
 612
 613 static void ftrace_startup_enable(int command)
 614 {
 615         if (saved_ftrace_func != ftrace_trace_function) {
 616                 saved_ftrace_func = ftrace_trace_function;
 617                 command |= FTRACE_UPDATE_TRACE_FUNC;
 618         }
 619
 620         if (!command || !ftrace_enabled)
 621                 return;
 622
 623         ftrace_run_update_code(command);
 624 }
 625
 626 static void ftrace_startup(int command)
 627 {
 628         if (unlikely(ftrace_disabled))
 629                 return;
 630
 631         mutex_lock(&ftrace_start_lock);
 632         ftrace_start_up++;
 633         command |= FTRACE_ENABLE_CALLS;
 634
 635         ftrace_startup_enable(command);
 636
 637         mutex_unlock(&ftrace_start_lock);
 638 }
 639
 640 static void ftrace_shutdown(int command)
 641 {
 642         if (unlikely(ftrace_disabled))
 643                 return;
 644
 645         mutex_lock(&ftrace_start_lock);
 646         ftrace_start_up--;
 647         if (!ftrace_start_up)
 648                 command |= FTRACE_DISABLE_CALLS;
 649
 650         if (saved_ftrace_func != ftrace_trace_function) {
 651                 saved_ftrace_func = ftrace_trace_function;
 652                 command |= FTRACE_UPDATE_TRACE_FUNC;
 653         }
 654
 655         if (!command || !ftrace_enabled)
 656                 goto out;
 657
 658         ftrace_run_update_code(command);
 659  out:
 660         mutex_unlock(&ftrace_start_lock);
 661 }
 662
 663 static void ftrace_startup_sysctl(void)
 664 {
 665         int command = FTRACE_ENABLE_MCOUNT;
 666
 667         if (unlikely(ftrace_disabled))
 668                 return;
 669
 670         mutex_lock(&ftrace_start_lock);
 671         /* Force update next time */
 672         saved_ftrace_func = NULL;
 673         /* ftrace_start_up is true if we want ftrace running */
 674         if (ftrace_start_up)
 675                 command |= FTRACE_ENABLE_CALLS;
 676
 677         ftrace_run_update_code(command);
 678         mutex_unlock(&ftrace_start_lock);
 679 }
 680
 681 static void ftrace_shutdown_sysctl(void)
 682 {
 683         int command = FTRACE_DISABLE_MCOUNT;
 684
 685         if (unlikely(ftrace_disabled))
 686                 return;
 687
 688         mutex_lock(&ftrace_start_lock);
 689         /* ftrace_start_up is true if ftrace is running */
 690         if (ftrace_start_up)
 691                 command |= FTRACE_DISABLE_CALLS;
 692
 693         ftrace_run_update_code(command);
 694         mutex_unlock(&ftrace_start_lock);
 695 }
 696
 697 static cycle_t          ftrace_update_time;
 698 static unsigned long    ftrace_update_cnt;
 699 unsigned long           ftrace_update_tot_cnt;
 700
 701 static int ftrace_update_code(struct module *mod)
 702 {
 703         struct dyn_ftrace *p, *t;
 704         cycle_t start, stop;
 705
 706         start = ftrace_now(raw_smp_processor_id());
 707         ftrace_update_cnt = 0;
 708
 709         list_for_each_entry_safe(p, t, &ftrace_new_addrs, list) {
 710
 711                 /* If something went wrong, bail without enabling anything */
 712                 if (unlikely(ftrace_disabled))
 713                         return -1;
 714
 715                 list_del_init(&p->list);
 716
 717                 /* convert record (i.e, patch mcount-call with NOP) */
 718                 if (ftrace_code_disable(mod, p)) {
 719                         p->flags |= FTRACE_FL_CONVERTED;
 720                         ftrace_update_cnt++;
 721                 } else
 722                         ftrace_free_rec(p);
 723         }
 724
 725         stop = ftrace_now(raw_smp_processor_id());
 726         ftrace_update_time = stop - start;
 727         ftrace_update_tot_cnt += ftrace_update_cnt;
 728
 729         return 0;
 730 }
 731
 732 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
 733 {
 734         struct ftrace_page *pg;
 735         int cnt;
 736         int i;
 737
 738         /* allocate a few pages */
 739         ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
 740         if (!ftrace_pages_start)
 741                 return -1;
 742
 743         /*
 744          * Allocate a few more pages.
 745          *
 746          * TODO: have some parser search vmlinux before
 747          *   final linking to find all calls to ftrace.
 748          *   Then we can:
 749          *    a) know how many pages to allocate.
 750          *     and/or
 751          *    b) set up the table then.
 752          *
 753          *  The dynamic code is still necessary for
 754          *  modules.
 755          */
 756
 757         pg = ftrace_pages = ftrace_pages_start;
 758
 759         cnt = num_to_init / ENTRIES_PER_PAGE;
 760         pr_info("ftrace: allocating %ld entries in %d pages\n",
 761                 num_to_init, cnt + 1);
 762
 763         for (i = 0; i < cnt; i++) {
 764                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
 765
 766                 /* If we fail, we'll try later anyway */
 767                 if (!pg->next)
 768                         break;
 769
 770                 pg = pg->next;
 771         }
 772
 773         return 0;
 774 }
 775
 776 enum {
 777         FTRACE_ITER_FILTER      = (1 << 0),
 778         FTRACE_ITER_CONT        = (1 << 1),
 779         FTRACE_ITER_NOTRACE     = (1 << 2),
 780         FTRACE_ITER_FAILURES    = (1 << 3),
 781         FTRACE_ITER_PRINTALL    = (1 << 4),
 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         int                     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         if (iter->flags & FTRACE_ITER_PRINTALL)
 804                 return NULL;
 805
 806         /* should not be called from interrupt context */
 807         spin_lock(&ftrace_lock);
 808  retry:
 809         if (iter->idx >= iter->pg->index) {
 810                 if (iter->pg->next) {
 811                         iter->pg = iter->pg->next;
 812                         iter->idx = 0;
 813                         goto retry;
 814                 } else {
 815                         iter->idx = -1;
 816                 }
 817         } else {
 818                 rec = &iter->pg->records[iter->idx++];
 819                 if ((rec->flags & FTRACE_FL_FREE) ||
 820
 821                     (!(iter->flags & FTRACE_ITER_FAILURES) &&
 822                      (rec->flags & FTRACE_FL_FAILED)) ||
 823
 824                     ((iter->flags & FTRACE_ITER_FAILURES) &&
 825                      !(rec->flags & FTRACE_FL_FAILED)) ||
 826
 827                     ((iter->flags & FTRACE_ITER_FILTER) &&
 828                      !(rec->flags & FTRACE_FL_FILTER)) ||
 829
 830                     ((iter->flags & FTRACE_ITER_NOTRACE) &&
 831                      !(rec->flags & FTRACE_FL_NOTRACE))) {
 832                         rec = NULL;
 833                         goto retry;
 834                 }
 835         }
 836         spin_unlock(&ftrace_lock);
 837
 838         return rec;
 839 }
 840
 841 static void *t_start(struct seq_file *m, loff_t *pos)
 842 {
 843         struct ftrace_iterator *iter = m->private;
 844         void *p = NULL;
 845
 846         /*
 847          * For set_ftrace_filter reading, if we have the filter
 848          * off, we can short cut and just print out that all
 849          * functions are enabled.
 850          */
 851         if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) {
 852                 if (*pos > 0)
 853                         return NULL;
 854                 iter->flags |= FTRACE_ITER_PRINTALL;
 855                 (*pos)++;
 856                 return iter;
 857         }
 858
 859         if (*pos > 0) {
 860                 if (iter->idx < 0)
 861                         return p;
 862                 (*pos)--;
 863                 iter->idx--;
 864         }
 865
 866         p = t_next(m, p, pos);
 867
 868         return p;
 869 }
 870
 871 static void t_stop(struct seq_file *m, void *p)
 872 {
 873 }
 874
 875 static int t_show(struct seq_file *m, void *v)
 876 {
 877         struct ftrace_iterator *iter = m->private;
 878         struct dyn_ftrace *rec = v;
 879         char str[KSYM_SYMBOL_LEN];
 880
 881         if (iter->flags & FTRACE_ITER_PRINTALL) {
 882                 seq_printf(m, "#### all functions enabled ####\n");
 883                 return 0;
 884         }
 885
 886         if (!rec)
 887                 return 0;
 888
 889         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 890
 891         seq_printf(m, "%s\n", str);
 892
 893         return 0;
 894 }
 895
 896 static struct seq_operations show_ftrace_seq_ops = {
 897         .start = t_start,
 898         .next = t_next,
 899         .stop = t_stop,
 900         .show = t_show,
 901 };
 902
 903 static int
 904 ftrace_avail_open(struct inode *inode, struct file *file)
 905 {
 906         struct ftrace_iterator *iter;
 907         int ret;
 908
 909         if (unlikely(ftrace_disabled))
 910                 return -ENODEV;
 911
 912         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
 913         if (!iter)
 914                 return -ENOMEM;
 915
 916         iter->pg = ftrace_pages_start;
 917
 918         ret = seq_open(file, &show_ftrace_seq_ops);
 919         if (!ret) {
 920                 struct seq_file *m = file->private_data;
 921
 922                 m->private = iter;
 923         } else {
 924                 kfree(iter);
 925         }
 926
 927         return ret;
 928 }
 929
 930 int ftrace_avail_release(struct inode *inode, struct file *file)
 931 {
 932         struct seq_file *m = (struct seq_file *)file->private_data;
 933         struct ftrace_iterator *iter = m->private;
 934
 935         seq_release(inode, file);
 936         kfree(iter);
 937
 938         return 0;
 939 }
 940
 941 static int
 942 ftrace_failures_open(struct inode *inode, struct file *file)
 943 {
 944         int ret;
 945         struct seq_file *m;
 946         struct ftrace_iterator *iter;
 947
 948         ret = ftrace_avail_open(inode, file);
 949         if (!ret) {
 950                 m = (struct seq_file *)file->private_data;
 951                 iter = (struct ftrace_iterator *)m->private;
 952                 iter->flags = FTRACE_ITER_FAILURES;
 953         }
 954
 955         return ret;
 956 }
 957
 958
 959 static void ftrace_filter_reset(int enable)
 960 {
 961         struct ftrace_page *pg;
 962         struct dyn_ftrace *rec;
 963         unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
 964
 965         /* should not be called from interrupt context */
 966         spin_lock(&ftrace_lock);
 967         if (enable)
 968                 ftrace_filtered = 0;
 969         do_for_each_ftrace_rec(pg, rec) {
 970                 if (rec->flags & FTRACE_FL_FAILED)
 971                         continue;
 972                 rec->flags &= ~type;
 973         } while_for_each_ftrace_rec();
 974
 975         spin_unlock(&ftrace_lock);
 976 }
 977
 978 static int
 979 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
 980 {
 981         struct ftrace_iterator *iter;
 982         int ret = 0;
 983
 984         if (unlikely(ftrace_disabled))
 985                 return -ENODEV;
 986
 987         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
 988         if (!iter)
 989                 return -ENOMEM;
 990
 991         mutex_lock(&ftrace_regex_lock);
 992         if ((file->f_mode & FMODE_WRITE) &&
 993             !(file->f_flags & O_APPEND))
 994                 ftrace_filter_reset(enable);
 995
 996         if (file->f_mode & FMODE_READ) {
 997                 iter->pg = ftrace_pages_start;
 998                 iter->flags = enable ? FTRACE_ITER_FILTER :
 999                         FTRACE_ITER_NOTRACE;
1000
1001                 ret = seq_open(file, &show_ftrace_seq_ops);
1002                 if (!ret) {
1003                         struct seq_file *m = file->private_data;
1004                         m->private = iter;
1005                 } else
1006                         kfree(iter);
1007         } else
1008                 file->private_data = iter;
1009         mutex_unlock(&ftrace_regex_lock);
1010
1011         return ret;
1012 }
1013
1014 static int
1015 ftrace_filter_open(struct inode *inode, struct file *file)
1016 {
1017         return ftrace_regex_open(inode, file, 1);
1018 }
1019
1020 static int
1021 ftrace_notrace_open(struct inode *inode, struct file *file)
1022 {
1023         return ftrace_regex_open(inode, file, 0);
1024 }
1025
1026 static ssize_t
1027 ftrace_regex_read(struct file *file, char __user *ubuf,
1028                        size_t cnt, loff_t *ppos)
1029 {
1030         if (file->f_mode & FMODE_READ)
1031                 return seq_read(file, ubuf, cnt, ppos);
1032         else
1033                 return -EPERM;
1034 }
1035
1036 static loff_t
1037 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1038 {
1039         loff_t ret;
1040
1041         if (file->f_mode & FMODE_READ)
1042                 ret = seq_lseek(file, offset, origin);
1043         else
1044                 file->f_pos = ret = 1;
1045
1046         return ret;
1047 }
1048
1049 enum {
1050         MATCH_FULL,
1051         MATCH_FRONT_ONLY,
1052         MATCH_MIDDLE_ONLY,
1053         MATCH_END_ONLY,
1054 };
1055
1056 static void
1057 ftrace_match(unsigned char *buff, int len, int enable)
1058 {
1059         char str[KSYM_SYMBOL_LEN];
1060         char *search = NULL;
1061         struct ftrace_page *pg;
1062         struct dyn_ftrace *rec;
1063         int type = MATCH_FULL;
1064         unsigned long flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1065         unsigned i, match = 0, search_len = 0;
1066         int not = 0;
1067
1068         if (buff[0] == '!') {
1069                 not = 1;
1070                 buff++;
1071                 len--;
1072         }
1073
1074         for (i = 0; i < len; i++) {
1075                 if (buff[i] == '*') {
1076                         if (!i) {
1077                                 search = buff + i + 1;
1078                                 type = MATCH_END_ONLY;
1079                                 search_len = len - (i + 1);
1080                         } else {
1081                                 if (type == MATCH_END_ONLY) {
1082                                         type = MATCH_MIDDLE_ONLY;
1083                                 } else {
1084                                         match = i;
1085                                         type = MATCH_FRONT_ONLY;
1086                                 }
1087                                 buff[i] = 0;
1088                                 break;
1089                         }
1090                 }
1091         }
1092
1093         /* should not be called from interrupt context */
1094         spin_lock(&ftrace_lock);
1095         if (enable)
1096                 ftrace_filtered = 1;
1097         do_for_each_ftrace_rec(pg, rec) {
1098                 int matched = 0;
1099                 char *ptr;
1100
1101                 if (rec->flags & FTRACE_FL_FAILED)
1102                         continue;
1103                 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1104                 switch (type) {
1105                 case MATCH_FULL:
1106                         if (strcmp(str, buff) == 0)
1107                                 matched = 1;
1108                         break;
1109                 case MATCH_FRONT_ONLY:
1110                         if (memcmp(str, buff, match) == 0)
1111                                 matched = 1;
1112                         break;
1113                 case MATCH_MIDDLE_ONLY:
1114                         if (strstr(str, search))
1115                                 matched = 1;
1116                         break;
1117                 case MATCH_END_ONLY:
1118                         ptr = strstr(str, search);
1119                         if (ptr && (ptr[search_len] == 0))
1120                                 matched = 1;
1121                         break;
1122                 }
1123                 if (matched) {
1124                         if (not)
1125                                 rec->flags &= ~flag;
1126                         else
1127                                 rec->flags |= flag;
1128                 }
1129         } while_for_each_ftrace_rec();
1130         spin_unlock(&ftrace_lock);
1131 }
1132
1133 static ssize_t
1134 ftrace_regex_write(struct file *file, const char __user *ubuf,
1135                    size_t cnt, loff_t *ppos, int enable)
1136 {
1137         struct ftrace_iterator *iter;
1138         char ch;
1139         size_t read = 0;
1140         ssize_t ret;
1141
1142         if (!cnt || cnt < 0)
1143                 return 0;
1144
1145         mutex_lock(&ftrace_regex_lock);
1146
1147         if (file->f_mode & FMODE_READ) {
1148                 struct seq_file *m = file->private_data;
1149                 iter = m->private;
1150         } else
1151                 iter = file->private_data;
1152
1153         if (!*ppos) {
1154                 iter->flags &= ~FTRACE_ITER_CONT;
1155                 iter->buffer_idx = 0;
1156         }
1157
1158         ret = get_user(ch, ubuf++);
1159         if (ret)
1160                 goto out;
1161         read++;
1162         cnt--;
1163
1164         if (!(iter->flags & ~FTRACE_ITER_CONT)) {
1165                 /* skip white space */
1166                 while (cnt && isspace(ch)) {
1167                         ret = get_user(ch, ubuf++);
1168                         if (ret)
1169                                 goto out;
1170                         read++;
1171                         cnt--;
1172                 }
1173
1174                 if (isspace(ch)) {
1175                         file->f_pos += read;
1176                         ret = read;
1177                         goto out;
1178                 }
1179
1180                 iter->buffer_idx = 0;
1181         }
1182
1183         while (cnt && !isspace(ch)) {
1184                 if (iter->buffer_idx < FTRACE_BUFF_MAX)
1185                         iter->buffer[iter->buffer_idx++] = ch;
1186                 else {
1187                         ret = -EINVAL;
1188                         goto out;
1189                 }
1190                 ret = get_user(ch, ubuf++);
1191                 if (ret)
1192                         goto out;
1193                 read++;
1194                 cnt--;
1195         }
1196
1197         if (isspace(ch)) {
1198                 iter->filtered++;
1199                 iter->buffer[iter->buffer_idx] = 0;
1200                 ftrace_match(iter->buffer, iter->buffer_idx, enable);
1201                 iter->buffer_idx = 0;
1202         } else
1203                 iter->flags |= FTRACE_ITER_CONT;
1204
1205
1206         file->f_pos += read;
1207
1208         ret = read;
1209  out:
1210         mutex_unlock(&ftrace_regex_lock);
1211
1212         return ret;
1213 }
1214
1215 static ssize_t
1216 ftrace_filter_write(struct file *file, const char __user *ubuf,
1217                     size_t cnt, loff_t *ppos)
1218 {
1219         return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
1220 }
1221
1222 static ssize_t
1223 ftrace_notrace_write(struct file *file, const char __user *ubuf,
1224                      size_t cnt, loff_t *ppos)
1225 {
1226         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
1227 }
1228
1229 static void
1230 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
1231 {
1232         if (unlikely(ftrace_disabled))
1233                 return;
1234
1235         mutex_lock(&ftrace_regex_lock);
1236         if (reset)
1237                 ftrace_filter_reset(enable);
1238         if (buf)
1239                 ftrace_match(buf, len, enable);
1240         mutex_unlock(&ftrace_regex_lock);
1241 }
1242
1243 /**
1244  * ftrace_set_filter - set a function to filter on in ftrace
1245  * @buf - the string that holds the function filter text.
1246  * @len - the length of the string.
1247  * @reset - non zero to reset all filters before applying this filter.
1248  *
1249  * Filters denote which functions should be enabled when tracing is enabled.
1250  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
1251  */
1252 void ftrace_set_filter(unsigned char *buf, int len, int reset)
1253 {
1254         ftrace_set_regex(buf, len, reset, 1);
1255 }
1256
1257 /**
1258  * ftrace_set_notrace - set a function to not trace in ftrace
1259  * @buf - the string that holds the function notrace text.
1260  * @len - the length of the string.
1261  * @reset - non zero to reset all filters before applying this filter.
1262  *
1263  * Notrace Filters denote which functions should not be enabled when tracing
1264  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
1265  * for tracing.
1266  */
1267 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
1268 {
1269         ftrace_set_regex(buf, len, reset, 0);
1270 }
1271
1272 static int
1273 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
1274 {
1275         struct seq_file *m = (struct seq_file *)file->private_data;
1276         struct ftrace_iterator *iter;
1277
1278         mutex_lock(&ftrace_regex_lock);
1279         if (file->f_mode & FMODE_READ) {
1280                 iter = m->private;
1281
1282                 seq_release(inode, file);
1283         } else
1284                 iter = file->private_data;
1285
1286         if (iter->buffer_idx) {
1287                 iter->filtered++;
1288                 iter->buffer[iter->buffer_idx] = 0;
1289                 ftrace_match(iter->buffer, iter->buffer_idx, enable);
1290         }
1291
1292         mutex_lock(&ftrace_sysctl_lock);
1293         mutex_lock(&ftrace_start_lock);
1294         if (ftrace_start_up && ftrace_enabled)
1295                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
1296         mutex_unlock(&ftrace_start_lock);
1297         mutex_unlock(&ftrace_sysctl_lock);
1298
1299         kfree(iter);
1300         mutex_unlock(&ftrace_regex_lock);
1301         return 0;
1302 }
1303
1304 static int
1305 ftrace_filter_release(struct inode *inode, struct file *file)
1306 {
1307         return ftrace_regex_release(inode, file, 1);
1308 }
1309
1310 static int
1311 ftrace_notrace_release(struct inode *inode, struct file *file)
1312 {
1313         return ftrace_regex_release(inode, file, 0);
1314 }
1315
1316 static struct file_operations ftrace_avail_fops = {
1317         .open = ftrace_avail_open,
1318         .read = seq_read,
1319         .llseek = seq_lseek,
1320         .release = ftrace_avail_release,
1321 };
1322
1323 static struct file_operations ftrace_failures_fops = {
1324         .open = ftrace_failures_open,
1325         .read = seq_read,
1326         .llseek = seq_lseek,
1327         .release = ftrace_avail_release,
1328 };
1329
1330 static struct file_operations ftrace_filter_fops = {
1331         .open = ftrace_filter_open,
1332         .read = ftrace_regex_read,
1333         .write = ftrace_filter_write,
1334         .llseek = ftrace_regex_lseek,
1335         .release = ftrace_filter_release,
1336 };
1337
1338 static struct file_operations ftrace_notrace_fops = {
1339         .open = ftrace_notrace_open,
1340         .read = ftrace_regex_read,
1341         .write = ftrace_notrace_write,
1342         .llseek = ftrace_regex_lseek,
1343         .release = ftrace_notrace_release,
1344 };
1345
1346 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1347
1348 static DEFINE_MUTEX(graph_lock);
1349
1350 int ftrace_graph_count;
1351 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
1352
1353 static void *
1354 g_next(struct seq_file *m, void *v, loff_t *pos)
1355 {
1356         unsigned long *array = m->private;
1357         int index = *pos;
1358
1359         (*pos)++;
1360
1361         if (index >= ftrace_graph_count)
1362                 return NULL;
1363
1364         return &array[index];
1365 }
1366
1367 static void *g_start(struct seq_file *m, loff_t *pos)
1368 {
1369         void *p = NULL;
1370
1371         mutex_lock(&graph_lock);
1372
1373         p = g_next(m, p, pos);
1374
1375         return p;
1376 }
1377
1378 static void g_stop(struct seq_file *m, void *p)
1379 {
1380         mutex_unlock(&graph_lock);
1381 }
1382
1383 static int g_show(struct seq_file *m, void *v)
1384 {
1385         unsigned long *ptr = v;
1386         char str[KSYM_SYMBOL_LEN];
1387
1388         if (!ptr)
1389                 return 0;
1390
1391         kallsyms_lookup(*ptr, NULL, NULL, NULL, str);
1392
1393         seq_printf(m, "%s\n", str);
1394
1395         return 0;
1396 }
1397
1398 static struct seq_operations ftrace_graph_seq_ops = {
1399         .start = g_start,
1400         .next = g_next,
1401         .stop = g_stop,
1402         .show = g_show,
1403 };
1404
1405 static int
1406 ftrace_graph_open(struct inode *inode, struct file *file)
1407 {
1408         int ret = 0;
1409
1410         if (unlikely(ftrace_disabled))
1411                 return -ENODEV;
1412
1413         mutex_lock(&graph_lock);
1414         if ((file->f_mode & FMODE_WRITE) &&
1415             !(file->f_flags & O_APPEND)) {
1416                 ftrace_graph_count = 0;
1417                 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
1418         }
1419
1420         if (file->f_mode & FMODE_READ) {
1421                 ret = seq_open(file, &ftrace_graph_seq_ops);
1422                 if (!ret) {
1423                         struct seq_file *m = file->private_data;
1424                         m->private = ftrace_graph_funcs;
1425                 }
1426         } else
1427                 file->private_data = ftrace_graph_funcs;
1428         mutex_unlock(&graph_lock);
1429
1430         return ret;
1431 }
1432
1433 static ssize_t
1434 ftrace_graph_read(struct file *file, char __user *ubuf,
1435                        size_t cnt, loff_t *ppos)
1436 {
1437         if (file->f_mode & FMODE_READ)
1438                 return seq_read(file, ubuf, cnt, ppos);
1439         else
1440                 return -EPERM;
1441 }
1442
1443 static int
1444 ftrace_set_func(unsigned long *array, int idx, char *buffer)
1445 {
1446         char str[KSYM_SYMBOL_LEN];
1447         struct dyn_ftrace *rec;
1448         struct ftrace_page *pg;
1449         int found = 0;
1450         int j;
1451
1452         if (ftrace_disabled)
1453                 return -ENODEV;
1454
1455         /* should not be called from interrupt context */
1456         spin_lock(&ftrace_lock);
1457
1458         do_for_each_ftrace_rec(pg, rec) {
1459
1460                 if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
1461                         continue;
1462
1463                 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1464                 if (strcmp(str, buffer) == 0) {
1465                         /* Return 1 if we add it to the array */
1466                         found = 1;
1467                         for (j = 0; j < idx; j++)
1468                                 if (array[j] == rec->ip) {
1469                                         found = 0;
1470                                         break;
1471                                 }
1472                         if (found)
1473                                 array[idx] = rec->ip;
1474                         goto out;
1475                 }
1476         } while_for_each_ftrace_rec();
1477  out:
1478         spin_unlock(&ftrace_lock);
1479
1480         return found ? 0 : -EINVAL;
1481 }
1482
1483 static ssize_t
1484 ftrace_graph_write(struct file *file, const char __user *ubuf,
1485                    size_t cnt, loff_t *ppos)
1486 {
1487         unsigned char buffer[FTRACE_BUFF_MAX+1];
1488         unsigned long *array;
1489         size_t read = 0;
1490         ssize_t ret;
1491         int index = 0;
1492         char ch;
1493
1494         if (!cnt || cnt < 0)
1495                 return 0;
1496
1497         mutex_lock(&graph_lock);
1498
1499         if (ftrace_graph_count >= FTRACE_GRAPH_MAX_FUNCS) {
1500                 ret = -EBUSY;
1501                 goto out;
1502         }
1503
1504         if (file->f_mode & FMODE_READ) {
1505                 struct seq_file *m = file->private_data;
1506                 array = m->private;
1507         } else
1508                 array = file->private_data;
1509
1510         ret = get_user(ch, ubuf++);
1511         if (ret)
1512                 goto out;
1513         read++;
1514         cnt--;
1515
1516         /* skip white space */
1517         while (cnt && isspace(ch)) {
1518                 ret = get_user(ch, ubuf++);
1519                 if (ret)
1520                         goto out;
1521                 read++;
1522                 cnt--;
1523         }
1524
1525         if (isspace(ch)) {
1526                 *ppos += read;
1527                 ret = read;
1528                 goto out;
1529         }
1530
1531         while (cnt && !isspace(ch)) {
1532                 if (index < FTRACE_BUFF_MAX)
1533                         buffer[index++] = ch;
1534                 else {
1535                         ret = -EINVAL;
1536                         goto out;
1537                 }
1538                 ret = get_user(ch, ubuf++);
1539                 if (ret)
1540                         goto out;
1541                 read++;
1542                 cnt--;
1543         }
1544         buffer[index] = 0;
1545
1546         /* we allow only one at a time */
1547         ret = ftrace_set_func(array, ftrace_graph_count, buffer);
1548         if (ret)
1549                 goto out;
1550
1551         ftrace_graph_count++;
1552
1553         file->f_pos += read;
1554
1555         ret = read;
1556  out:
1557         mutex_unlock(&graph_lock);
1558
1559         return ret;
1560 }
1561
1562 static const struct file_operations ftrace_graph_fops = {
1563         .open = ftrace_graph_open,
1564         .read = ftrace_graph_read,
1565         .write = ftrace_graph_write,
1566 };
1567 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1568
1569 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
1570 {
1571         struct dentry *entry;
1572
1573         entry = debugfs_create_file("available_filter_functions", 0444,
1574                                     d_tracer, NULL, &ftrace_avail_fops);
1575         if (!entry)
1576                 pr_warning("Could not create debugfs "
1577                            "'available_filter_functions' entry\n");
1578
1579         entry = debugfs_create_file("failures", 0444,
1580                                     d_tracer, NULL, &ftrace_failures_fops);
1581         if (!entry)
1582                 pr_warning("Could not create debugfs 'failures' entry\n");
1583
1584         entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer,
1585                                     NULL, &ftrace_filter_fops);
1586         if (!entry)
1587                 pr_warning("Could not create debugfs "
1588                            "'set_ftrace_filter' entry\n");
1589
1590         entry = debugfs_create_file("set_ftrace_notrace", 0644, d_tracer,
1591                                     NULL, &ftrace_notrace_fops);
1592         if (!entry)
1593                 pr_warning("Could not create debugfs "
1594                            "'set_ftrace_notrace' entry\n");
1595
1596 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1597         entry = debugfs_create_file("set_graph_function", 0444, d_tracer,
1598                                     NULL,
1599                                     &ftrace_graph_fops);
1600         if (!entry)
1601                 pr_warning("Could not create debugfs "
1602                            "'set_graph_function' entry\n");
1603 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1604
1605         return 0;
1606 }
1607
1608 static int ftrace_convert_nops(struct module *mod,
1609                                unsigned long *start,
1610                                unsigned long *end)
1611 {
1612         unsigned long *p;
1613         unsigned long addr;
1614         unsigned long flags;
1615
1616         mutex_lock(&ftrace_start_lock);
1617         p = start;
1618         while (p < end) {
1619                 addr = ftrace_call_adjust(*p++);
1620                 /*
1621                  * Some architecture linkers will pad between
1622                  * the different mcount_loc sections of different
1623                  * object files to satisfy alignments.
1624                  * Skip any NULL pointers.
1625                  */
1626                 if (!addr)
1627                         continue;
1628                 ftrace_record_ip(addr);
1629         }
1630
1631         /* disable interrupts to prevent kstop machine */
1632         local_irq_save(flags);
1633         ftrace_update_code(mod);
1634         local_irq_restore(flags);
1635         mutex_unlock(&ftrace_start_lock);
1636
1637         return 0;
1638 }
1639
1640 void ftrace_init_module(struct module *mod,
1641                         unsigned long *start, unsigned long *end)
1642 {
1643         if (ftrace_disabled || start == end)
1644                 return;
1645         ftrace_convert_nops(mod, start, end);
1646 }
1647
1648 extern unsigned long __start_mcount_loc[];
1649 extern unsigned long __stop_mcount_loc[];
1650
1651 void __init ftrace_init(void)
1652 {
1653         unsigned long count, addr, flags;
1654         int ret;
1655
1656         /* Keep the ftrace pointer to the stub */
1657         addr = (unsigned long)ftrace_stub;
1658
1659         local_irq_save(flags);
1660         ftrace_dyn_arch_init(&addr);
1661         local_irq_restore(flags);
1662
1663         /* ftrace_dyn_arch_init places the return code in addr */
1664         if (addr)
1665                 goto failed;
1666
1667         count = __stop_mcount_loc - __start_mcount_loc;
1668
1669         ret = ftrace_dyn_table_alloc(count);
1670         if (ret)
1671                 goto failed;
1672
1673         last_ftrace_enabled = ftrace_enabled = 1;
1674
1675         ret = ftrace_convert_nops(NULL,
1676                                   __start_mcount_loc,
1677                                   __stop_mcount_loc);
1678
1679         return;
1680  failed:
1681         ftrace_disabled = 1;
1682 }
1683
1684 #else
1685
1686 static int __init ftrace_nodyn_init(void)
1687 {
1688         ftrace_enabled = 1;
1689         return 0;
1690 }
1691 device_initcall(ftrace_nodyn_init);
1692
1693 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
1694 static inline void ftrace_startup_enable(int command) { }
1695 /* Keep as macros so we do not need to define the commands */
1696 # define ftrace_startup(command)        do { } while (0)
1697 # define ftrace_shutdown(command)       do { } while (0)
1698 # define ftrace_startup_sysctl()        do { } while (0)
1699 # define ftrace_shutdown_sysctl()       do { } while (0)
1700 #endif /* CONFIG_DYNAMIC_FTRACE */
1701
1702 static ssize_t
1703 ftrace_pid_read(struct file *file, char __user *ubuf,
1704                        size_t cnt, loff_t *ppos)
1705 {
1706         char buf[64];
1707         int r;
1708
1709         if (ftrace_pid_trace == ftrace_swapper_pid)
1710                 r = sprintf(buf, "swapper tasks\n");
1711         else if (ftrace_pid_trace)
1712                 r = sprintf(buf, "%u\n", pid_nr(ftrace_pid_trace));
1713         else
1714                 r = sprintf(buf, "no pid\n");
1715
1716         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1717 }
1718
1719 static void clear_ftrace_swapper(void)
1720 {
1721         struct task_struct *p;
1722         int cpu;
1723
1724         get_online_cpus();
1725         for_each_online_cpu(cpu) {
1726                 p = idle_task(cpu);
1727                 clear_tsk_trace_trace(p);
1728         }
1729         put_online_cpus();
1730 }
1731
1732 static void set_ftrace_swapper(void)
1733 {
1734         struct task_struct *p;
1735         int cpu;
1736
1737         get_online_cpus();
1738         for_each_online_cpu(cpu) {
1739                 p = idle_task(cpu);
1740                 set_tsk_trace_trace(p);
1741         }
1742         put_online_cpus();
1743 }
1744
1745 static void clear_ftrace_pid(struct pid *pid)
1746 {
1747         struct task_struct *p;
1748
1749         rcu_read_lock();
1750         do_each_pid_task(pid, PIDTYPE_PID, p) {
1751                 clear_tsk_trace_trace(p);
1752         } while_each_pid_task(pid, PIDTYPE_PID, p);
1753         rcu_read_unlock();
1754
1755         put_pid(pid);
1756 }
1757
1758 static void set_ftrace_pid(struct pid *pid)
1759 {
1760         struct task_struct *p;
1761
1762         rcu_read_lock();
1763         do_each_pid_task(pid, PIDTYPE_PID, p) {
1764                 set_tsk_trace_trace(p);
1765         } while_each_pid_task(pid, PIDTYPE_PID, p);
1766         rcu_read_unlock();
1767 }
1768
1769 static void clear_ftrace_pid_task(struct pid **pid)
1770 {
1771         if (*pid == ftrace_swapper_pid)
1772                 clear_ftrace_swapper();
1773         else
1774                 clear_ftrace_pid(*pid);
1775
1776         *pid = NULL;
1777 }
1778
1779 static void set_ftrace_pid_task(struct pid *pid)
1780 {
1781         if (pid == ftrace_swapper_pid)
1782                 set_ftrace_swapper();
1783         else
1784                 set_ftrace_pid(pid);
1785 }
1786
1787 static ssize_t
1788 ftrace_pid_write(struct file *filp, const char __user *ubuf,
1789                    size_t cnt, loff_t *ppos)
1790 {
1791         struct pid *pid;
1792         char buf[64];
1793         long val;
1794         int ret;
1795
1796         if (cnt >= sizeof(buf))
1797                 return -EINVAL;
1798
1799         if (copy_from_user(&buf, ubuf, cnt))
1800                 return -EFAULT;
1801
1802         buf[cnt] = 0;
1803
1804         ret = strict_strtol(buf, 10, &val);
1805         if (ret < 0)
1806                 return ret;
1807
1808         mutex_lock(&ftrace_start_lock);
1809         if (val < 0) {
1810                 /* disable pid tracing */
1811                 if (!ftrace_pid_trace)
1812                         goto out;
1813
1814                 clear_ftrace_pid_task(&ftrace_pid_trace);
1815
1816         } else {
1817                 /* swapper task is special */
1818                 if (!val) {
1819                         pid = ftrace_swapper_pid;
1820                         if (pid == ftrace_pid_trace)
1821                                 goto out;
1822                 } else {
1823                         pid = find_get_pid(val);
1824
1825                         if (pid == ftrace_pid_trace) {
1826                                 put_pid(pid);
1827                                 goto out;
1828                         }
1829                 }
1830
1831                 if (ftrace_pid_trace)
1832                         clear_ftrace_pid_task(&ftrace_pid_trace);
1833
1834                 if (!pid)
1835                         goto out;
1836
1837                 ftrace_pid_trace = pid;
1838
1839                 set_ftrace_pid_task(ftrace_pid_trace);
1840         }
1841
1842         /* update the function call */
1843         ftrace_update_pid_func();
1844         ftrace_startup_enable(0);
1845
1846  out:
1847         mutex_unlock(&ftrace_start_lock);
1848
1849         return cnt;
1850 }
1851
1852 static struct file_operations ftrace_pid_fops = {
1853         .read = ftrace_pid_read,
1854         .write = ftrace_pid_write,
1855 };
1856
1857 static __init int ftrace_init_debugfs(void)
1858 {
1859         struct dentry *d_tracer;
1860         struct dentry *entry;
1861
1862         d_tracer = tracing_init_dentry();
1863         if (!d_tracer)
1864                 return 0;
1865
1866         ftrace_init_dyn_debugfs(d_tracer);
1867
1868         entry = debugfs_create_file("set_ftrace_pid", 0644, d_tracer,
1869                                     NULL, &ftrace_pid_fops);
1870         if (!entry)
1871                 pr_warning("Could not create debugfs "
1872                            "'set_ftrace_pid' entry\n");
1873         return 0;
1874 }
1875
1876 fs_initcall(ftrace_init_debugfs);
1877
1878 /**
1879  * ftrace_kill - kill ftrace
1880  *
1881  * This function should be used by panic code. It stops ftrace
1882  * but in a not so nice way. If you need to simply kill ftrace
1883  * from a non-atomic section, use ftrace_kill.
1884  */
1885 void ftrace_kill(void)
1886 {
1887         ftrace_disabled = 1;
1888         ftrace_enabled = 0;
1889         clear_ftrace_function();
1890 }
1891
1892 /**
1893  * register_ftrace_function - register a function for profiling
1894  * @ops - ops structure that holds the function for profiling.
1895  *
1896  * Register a function to be called by all functions in the
1897  * kernel.
1898  *
1899  * Note: @ops->func and all the functions it calls must be labeled
1900  *       with "notrace", otherwise it will go into a
1901  *       recursive loop.
1902  */
1903 int register_ftrace_function(struct ftrace_ops *ops)
1904 {
1905         int ret;
1906
1907         if (unlikely(ftrace_disabled))
1908                 return -1;
1909
1910         mutex_lock(&ftrace_sysctl_lock);
1911
1912         ret = __register_ftrace_function(ops);
1913         ftrace_startup(0);
1914
1915         mutex_unlock(&ftrace_sysctl_lock);
1916         return ret;
1917 }
1918
1919 /**
1920  * unregister_ftrace_function - unregister a function for profiling.
1921  * @ops - ops structure that holds the function to unregister
1922  *
1923  * Unregister a function that was added to be called by ftrace profiling.
1924  */
1925 int unregister_ftrace_function(struct ftrace_ops *ops)
1926 {
1927         int ret;
1928
1929         mutex_lock(&ftrace_sysctl_lock);
1930         ret = __unregister_ftrace_function(ops);
1931         ftrace_shutdown(0);
1932         mutex_unlock(&ftrace_sysctl_lock);
1933
1934         return ret;
1935 }
1936
1937 int
1938 ftrace_enable_sysctl(struct ctl_table *table, int write,
1939                      struct file *file, void __user *buffer, size_t *lenp,
1940                      loff_t *ppos)
1941 {
1942         int ret;
1943
1944         if (unlikely(ftrace_disabled))
1945                 return -ENODEV;
1946
1947         mutex_lock(&ftrace_sysctl_lock);
1948
1949         ret  = proc_dointvec(table, write, file, buffer, lenp, ppos);
1950
1951         if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
1952                 goto out;
1953
1954         last_ftrace_enabled = ftrace_enabled;
1955
1956         if (ftrace_enabled) {
1957
1958                 ftrace_startup_sysctl();
1959
1960                 /* we are starting ftrace again */
1961                 if (ftrace_list != &ftrace_list_end) {
1962                         if (ftrace_list->next == &ftrace_list_end)
1963                                 ftrace_trace_function = ftrace_list->func;
1964                         else
1965                                 ftrace_trace_function = ftrace_list_func;
1966                 }
1967
1968         } else {
1969                 /* stopping ftrace calls (just send to ftrace_stub) */
1970                 ftrace_trace_function = ftrace_stub;
1971
1972                 ftrace_shutdown_sysctl();
1973         }
1974
1975  out:
1976         mutex_unlock(&ftrace_sysctl_lock);
1977         return ret;
1978 }
1979
1980 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1981
1982 static atomic_t ftrace_graph_active;
1983 static struct notifier_block ftrace_suspend_notifier;
1984
1985 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
1986 {
1987         return 0;
1988 }
1989
1990 /* The callbacks that hook a function */
1991 trace_func_graph_ret_t ftrace_graph_return =
1992                         (trace_func_graph_ret_t)ftrace_stub;
1993 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
1994
1995 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
1996 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
1997 {
1998         int i;
1999         int ret = 0;
2000         unsigned long flags;
2001         int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
2002         struct task_struct *g, *t;
2003
2004         for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
2005                 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
2006                                         * sizeof(struct ftrace_ret_stack),
2007                                         GFP_KERNEL);
2008                 if (!ret_stack_list[i]) {
2009                         start = 0;
2010                         end = i;
2011                         ret = -ENOMEM;
2012                         goto free;
2013                 }
2014         }
2015
2016         read_lock_irqsave(&tasklist_lock, flags);
2017         do_each_thread(g, t) {
2018                 if (start == end) {
2019                         ret = -EAGAIN;
2020                         goto unlock;
2021                 }
2022
2023                 if (t->ret_stack == NULL) {
2024                         t->curr_ret_stack = -1;
2025                         /* Make sure IRQs see the -1 first: */
2026                         barrier();
2027                         t->ret_stack = ret_stack_list[start++];
2028                         atomic_set(&t->tracing_graph_pause, 0);
2029                         atomic_set(&t->trace_overrun, 0);
2030                 }
2031         } while_each_thread(g, t);
2032
2033 unlock:
2034         read_unlock_irqrestore(&tasklist_lock, flags);
2035 free:
2036         for (i = start; i < end; i++)
2037                 kfree(ret_stack_list[i]);
2038         return ret;
2039 }
2040
2041 /* Allocate a return stack for each task */
2042 static int start_graph_tracing(void)
2043 {
2044         struct ftrace_ret_stack **ret_stack_list;
2045         int ret;
2046
2047         ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
2048                                 sizeof(struct ftrace_ret_stack *),
2049                                 GFP_KERNEL);
2050
2051         if (!ret_stack_list)
2052                 return -ENOMEM;
2053
2054         do {
2055                 ret = alloc_retstack_tasklist(ret_stack_list);
2056         } while (ret == -EAGAIN);
2057
2058         kfree(ret_stack_list);
2059         return ret;
2060 }
2061
2062 /*
2063  * Hibernation protection.
2064  * The state of the current task is too much unstable during
2065  * suspend/restore to disk. We want to protect against that.
2066  */
2067 static int
2068 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
2069                                                         void *unused)
2070 {
2071         switch (state) {
2072         case PM_HIBERNATION_PREPARE:
2073                 pause_graph_tracing();
2074                 break;
2075
2076         case PM_POST_HIBERNATION:
2077                 unpause_graph_tracing();
2078                 break;
2079         }
2080         return NOTIFY_DONE;
2081 }
2082
2083 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
2084                         trace_func_graph_ent_t entryfunc)
2085 {
2086         int ret = 0;
2087
2088         mutex_lock(&ftrace_sysctl_lock);
2089
2090         ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
2091         register_pm_notifier(&ftrace_suspend_notifier);
2092
2093         atomic_inc(&ftrace_graph_active);
2094         ret = start_graph_tracing();
2095         if (ret) {
2096                 atomic_dec(&ftrace_graph_active);
2097                 goto out;
2098         }
2099
2100         ftrace_graph_return = retfunc;
2101         ftrace_graph_entry = entryfunc;
2102
2103         ftrace_startup(FTRACE_START_FUNC_RET);
2104
2105 out:
2106         mutex_unlock(&ftrace_sysctl_lock);
2107         return ret;
2108 }
2109
2110 void unregister_ftrace_graph(void)
2111 {
2112         mutex_lock(&ftrace_sysctl_lock);
2113
2114         atomic_dec(&ftrace_graph_active);
2115         ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
2116         ftrace_graph_entry = ftrace_graph_entry_stub;
2117         ftrace_shutdown(FTRACE_STOP_FUNC_RET);
2118         unregister_pm_notifier(&ftrace_suspend_notifier);
2119
2120         mutex_unlock(&ftrace_sysctl_lock);
2121 }
2122
2123 /* Allocate a return stack for newly created task */
2124 void ftrace_graph_init_task(struct task_struct *t)
2125 {
2126         if (atomic_read(&ftrace_graph_active)) {
2127                 t->ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
2128                                 * sizeof(struct ftrace_ret_stack),
2129                                 GFP_KERNEL);
2130                 if (!t->ret_stack)
2131                         return;
2132                 t->curr_ret_stack = -1;
2133                 atomic_set(&t->tracing_graph_pause, 0);
2134                 atomic_set(&t->trace_overrun, 0);
2135         } else
2136                 t->ret_stack = NULL;
2137 }
2138
2139 void ftrace_graph_exit_task(struct task_struct *t)
2140 {
2141         struct ftrace_ret_stack *ret_stack = t->ret_stack;
2142
2143         t->ret_stack = NULL;
2144         /* NULL must become visible to IRQs before we free it: */
2145         barrier();
2146
2147         kfree(ret_stack);
2148 }
2149
2150 void ftrace_graph_stop(void)
2151 {
2152         ftrace_stop();
2153 }
2154 #endif
2155