git.oblomov.eu Git - linux-2.6/blob - 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 /*
1057  * (static function - no need for kernel doc)
1058  *
1059  * Pass in a buffer containing a glob and this function will
1060  * set search to point to the search part of the buffer and
1061  * return the type of search it is (see enum above).
1062  * This does modify buff.
1063  *
1064  * Returns enum type.
1065  *  search returns the pointer to use for comparison.
1066  *  not returns 1 if buff started with a '!'
1067  *     0 otherwise.
1068  */
1069 static int
1070 ftrace_setup_glob(char *buff, int len, char **search, int *not)
1071 {
1072         int type = MATCH_FULL;
1073         int i;
1074
1075         if (buff[0] == '!') {
1076                 *not = 1;
1077                 buff++;
1078                 len--;
1079         } else
1080                 *not = 0;
1081
1082         *search = buff;
1083
1084         for (i = 0; i < len; i++) {
1085                 if (buff[i] == '*') {
1086                         if (!i) {
1087                                 *search = buff + 1;
1088                                 type = MATCH_END_ONLY;
1089                         } else {
1090                                 if (type == MATCH_END_ONLY)
1091                                         type = MATCH_MIDDLE_ONLY;
1092                                 else
1093                                         type = MATCH_FRONT_ONLY;
1094                                 buff[i] = 0;
1095                                 break;
1096                         }
1097                 }
1098         }
1099
1100         return type;
1101 }
1102
1103 static int ftrace_match(char *str, char *regex, int len, int type)
1104 {
1105         int matched = 0;
1106         char *ptr;
1107
1108         switch (type) {
1109         case MATCH_FULL:
1110                 if (strcmp(str, regex) == 0)
1111                         matched = 1;
1112                 break;
1113         case MATCH_FRONT_ONLY:
1114                 if (strncmp(str, regex, len) == 0)
1115                         matched = 1;
1116                 break;
1117         case MATCH_MIDDLE_ONLY:
1118                 if (strstr(str, regex))
1119                         matched = 1;
1120                 break;
1121         case MATCH_END_ONLY:
1122                 ptr = strstr(str, regex);
1123                 if (ptr && (ptr[len] == 0))
1124                         matched = 1;
1125                 break;
1126         }
1127
1128         return matched;
1129 }
1130
1131 static int
1132 ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
1133 {
1134         char str[KSYM_SYMBOL_LEN];
1135
1136         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1137         return ftrace_match(str, regex, len, type);
1138 }
1139
1140 static void ftrace_match_records(char *buff, int len, int enable)
1141 {
1142         char *search;
1143         struct ftrace_page *pg;
1144         struct dyn_ftrace *rec;
1145         int type;
1146         unsigned long flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1147         unsigned search_len;
1148         int not;
1149
1150         type = ftrace_setup_glob(buff, len, &search, &not);
1151
1152         search_len = strlen(search);
1153
1154         /* should not be called from interrupt context */
1155         spin_lock(&ftrace_lock);
1156         do_for_each_ftrace_rec(pg, rec) {
1157
1158                 if (rec->flags & FTRACE_FL_FAILED)
1159                         continue;
1160
1161                 if (ftrace_match_record(rec, search, search_len, type)) {
1162                         if (not)
1163                                 rec->flags &= ~flag;
1164                         else
1165                                 rec->flags |= flag;
1166                 }
1167                 /*
1168                  * Only enable filtering if we have a function that
1169                  * is filtered on.
1170                  */
1171                 if (enable && (rec->flags & FTRACE_FL_FILTER))
1172                         ftrace_filtered = 1;
1173         } while_for_each_ftrace_rec();
1174         spin_unlock(&ftrace_lock);
1175 }
1176
1177 static int
1178 ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
1179                            char *regex, int len, int type)
1180 {
1181         char str[KSYM_SYMBOL_LEN];
1182         char *modname;
1183
1184         kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
1185
1186         if (!modname || strcmp(modname, mod))
1187                 return 0;
1188
1189         /* blank search means to match all funcs in the mod */
1190         if (len)
1191                 return ftrace_match(str, regex, len, type);
1192         else
1193                 return 1;
1194 }
1195
1196 static void ftrace_match_module_records(char *buff, char *mod, int enable)
1197 {
1198         char *search = buff;
1199         struct ftrace_page *pg;
1200         struct dyn_ftrace *rec;
1201         int type = MATCH_FULL;
1202         unsigned long flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1203         unsigned search_len = 0;
1204         int not = 0;
1205
1206         /* blank or '*' mean the same */
1207         if (strcmp(buff, "*") == 0)
1208                 buff[0] = 0;
1209
1210         /* handle the case of 'dont filter this module' */
1211         if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
1212                 buff[0] = 0;
1213                 not = 1;
1214         }
1215
1216         if (strlen(buff)) {
1217                 type = ftrace_setup_glob(buff, strlen(buff), &search, &not);
1218                 search_len = strlen(search);
1219         }
1220
1221         /* should not be called from interrupt context */
1222         spin_lock(&ftrace_lock);
1223         do_for_each_ftrace_rec(pg, rec) {
1224
1225                 if (rec->flags & FTRACE_FL_FAILED)
1226                         continue;
1227
1228                 if (ftrace_match_module_record(rec, mod,
1229                                                search, search_len, type)) {
1230                         if (not)
1231                                 rec->flags &= ~flag;
1232                         else
1233                                 rec->flags |= flag;
1234                 }
1235                 if (enable && (rec->flags & FTRACE_FL_FILTER))
1236                         ftrace_filtered = 1;
1237
1238         } while_for_each_ftrace_rec();
1239         spin_unlock(&ftrace_lock);
1240 }
1241
1242 /*
1243  * We register the module command as a template to show others how
1244  * to register the a command as well.
1245  */
1246
1247 static int
1248 ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
1249 {
1250         char *mod;
1251
1252         /*
1253          * cmd == 'mod' because we only registered this func
1254          * for the 'mod' ftrace_func_command.
1255          * But if you register one func with multiple commands,
1256          * you can tell which command was used by the cmd
1257          * parameter.
1258          */
1259
1260         /* we must have a module name */
1261         if (!param)
1262                 return -EINVAL;
1263
1264         mod = strsep(&param, ":");
1265         if (!strlen(mod))
1266                 return -EINVAL;
1267
1268         ftrace_match_module_records(func, mod, enable);
1269         return 0;
1270 }
1271
1272 static struct ftrace_func_command ftrace_mod_cmd = {
1273         .name                   = "mod",
1274         .func                   = ftrace_mod_callback,
1275 };
1276
1277 static int __init ftrace_mod_cmd_init(void)
1278 {
1279         return register_ftrace_command(&ftrace_mod_cmd);
1280 }
1281 device_initcall(ftrace_mod_cmd_init);
1282
1283 static LIST_HEAD(ftrace_commands);
1284 static DEFINE_MUTEX(ftrace_cmd_mutex);
1285
1286 int register_ftrace_command(struct ftrace_func_command *cmd)
1287 {
1288         struct ftrace_func_command *p;
1289         int ret = 0;
1290
1291         mutex_lock(&ftrace_cmd_mutex);
1292         list_for_each_entry(p, &ftrace_commands, list) {
1293                 if (strcmp(cmd->name, p->name) == 0) {
1294                         ret = -EBUSY;
1295                         goto out_unlock;
1296                 }
1297         }
1298         list_add(&cmd->list, &ftrace_commands);
1299  out_unlock:
1300         mutex_unlock(&ftrace_cmd_mutex);
1301
1302         return ret;
1303 }
1304
1305 int unregister_ftrace_command(struct ftrace_func_command *cmd)
1306 {
1307         struct ftrace_func_command *p, *n;
1308         int ret = -ENODEV;
1309
1310         mutex_lock(&ftrace_cmd_mutex);
1311         list_for_each_entry_safe(p, n, &ftrace_commands, list) {
1312                 if (strcmp(cmd->name, p->name) == 0) {
1313                         ret = 0;
1314                         list_del_init(&p->list);
1315                         goto out_unlock;
1316                 }
1317         }
1318  out_unlock:
1319         mutex_unlock(&ftrace_cmd_mutex);
1320
1321         return ret;
1322 }
1323
1324 static int ftrace_process_regex(char *buff, int len, int enable)
1325 {
1326         struct ftrace_func_command *p;
1327         char *func, *command, *next = buff;
1328         int ret = -EINVAL;
1329
1330         func = strsep(&next, ":");
1331
1332         if (!next) {
1333                 ftrace_match_records(func, len, enable);
1334                 return 0;
1335         }
1336
1337         /* command found */
1338
1339         command = strsep(&next, ":");
1340
1341         mutex_lock(&ftrace_cmd_mutex);
1342         list_for_each_entry(p, &ftrace_commands, list) {
1343                 if (strcmp(p->name, command) == 0) {
1344                         ret = p->func(func, command, next, enable);
1345                         goto out_unlock;
1346                 }
1347         }
1348  out_unlock:
1349         mutex_unlock(&ftrace_cmd_mutex);
1350
1351         return ret;
1352 }
1353
1354 static ssize_t
1355 ftrace_regex_write(struct file *file, const char __user *ubuf,
1356                    size_t cnt, loff_t *ppos, int enable)
1357 {
1358         struct ftrace_iterator *iter;
1359         char ch;
1360         size_t read = 0;
1361         ssize_t ret;
1362
1363         if (!cnt || cnt < 0)
1364                 return 0;
1365
1366         mutex_lock(&ftrace_regex_lock);
1367
1368         if (file->f_mode & FMODE_READ) {
1369                 struct seq_file *m = file->private_data;
1370                 iter = m->private;
1371         } else
1372                 iter = file->private_data;
1373
1374         if (!*ppos) {
1375                 iter->flags &= ~FTRACE_ITER_CONT;
1376                 iter->buffer_idx = 0;
1377         }
1378
1379         ret = get_user(ch, ubuf++);
1380         if (ret)
1381                 goto out;
1382         read++;
1383         cnt--;
1384
1385         if (!(iter->flags & ~FTRACE_ITER_CONT)) {
1386                 /* skip white space */
1387                 while (cnt && isspace(ch)) {
1388                         ret = get_user(ch, ubuf++);
1389                         if (ret)
1390                                 goto out;
1391                         read++;
1392                         cnt--;
1393                 }
1394
1395                 if (isspace(ch)) {
1396                         file->f_pos += read;
1397                         ret = read;
1398                         goto out;
1399                 }
1400
1401                 iter->buffer_idx = 0;
1402         }
1403
1404         while (cnt && !isspace(ch)) {
1405                 if (iter->buffer_idx < FTRACE_BUFF_MAX)
1406                         iter->buffer[iter->buffer_idx++] = ch;
1407                 else {
1408                         ret = -EINVAL;
1409                         goto out;
1410                 }
1411                 ret = get_user(ch, ubuf++);
1412                 if (ret)
1413                         goto out;
1414                 read++;
1415                 cnt--;
1416         }
1417
1418         if (isspace(ch)) {
1419                 iter->filtered++;
1420                 iter->buffer[iter->buffer_idx] = 0;
1421                 ret = ftrace_process_regex(iter->buffer,
1422                                            iter->buffer_idx, enable);
1423                 if (ret)
1424                         goto out;
1425                 iter->buffer_idx = 0;
1426         } else
1427                 iter->flags |= FTRACE_ITER_CONT;
1428
1429
1430         file->f_pos += read;
1431
1432         ret = read;
1433  out:
1434         mutex_unlock(&ftrace_regex_lock);
1435
1436         return ret;
1437 }
1438
1439 static ssize_t
1440 ftrace_filter_write(struct file *file, const char __user *ubuf,
1441                     size_t cnt, loff_t *ppos)
1442 {
1443         return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
1444 }
1445
1446 static ssize_t
1447 ftrace_notrace_write(struct file *file, const char __user *ubuf,
1448                      size_t cnt, loff_t *ppos)
1449 {
1450         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
1451 }
1452
1453 static void
1454 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
1455 {
1456         if (unlikely(ftrace_disabled))
1457                 return;
1458
1459         mutex_lock(&ftrace_regex_lock);
1460         if (reset)
1461                 ftrace_filter_reset(enable);
1462         if (buf)
1463                 ftrace_match_records(buf, len, enable);
1464         mutex_unlock(&ftrace_regex_lock);
1465 }
1466
1467 /**
1468  * ftrace_set_filter - set a function to filter on in ftrace
1469  * @buf - the string that holds the function filter text.
1470  * @len - the length of the string.
1471  * @reset - non zero to reset all filters before applying this filter.
1472  *
1473  * Filters denote which functions should be enabled when tracing is enabled.
1474  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
1475  */
1476 void ftrace_set_filter(unsigned char *buf, int len, int reset)
1477 {
1478         ftrace_set_regex(buf, len, reset, 1);
1479 }
1480
1481 /**
1482  * ftrace_set_notrace - set a function to not trace in ftrace
1483  * @buf - the string that holds the function notrace text.
1484  * @len - the length of the string.
1485  * @reset - non zero to reset all filters before applying this filter.
1486  *
1487  * Notrace Filters denote which functions should not be enabled when tracing
1488  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
1489  * for tracing.
1490  */
1491 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
1492 {
1493         ftrace_set_regex(buf, len, reset, 0);
1494 }
1495
1496 static int
1497 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
1498 {
1499         struct seq_file *m = (struct seq_file *)file->private_data;
1500         struct ftrace_iterator *iter;
1501
1502         mutex_lock(&ftrace_regex_lock);
1503         if (file->f_mode & FMODE_READ) {
1504                 iter = m->private;
1505
1506                 seq_release(inode, file);
1507         } else
1508                 iter = file->private_data;
1509
1510         if (iter->buffer_idx) {
1511                 iter->filtered++;
1512                 iter->buffer[iter->buffer_idx] = 0;
1513                 ftrace_match_records(iter->buffer, iter->buffer_idx, enable);
1514         }
1515
1516         mutex_lock(&ftrace_sysctl_lock);
1517         mutex_lock(&ftrace_start_lock);
1518         if (ftrace_start_up && ftrace_enabled)
1519                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
1520         mutex_unlock(&ftrace_start_lock);
1521         mutex_unlock(&ftrace_sysctl_lock);
1522
1523         kfree(iter);
1524         mutex_unlock(&ftrace_regex_lock);
1525         return 0;
1526 }
1527
1528 static int
1529 ftrace_filter_release(struct inode *inode, struct file *file)
1530 {
1531         return ftrace_regex_release(inode, file, 1);
1532 }
1533
1534 static int
1535 ftrace_notrace_release(struct inode *inode, struct file *file)
1536 {
1537         return ftrace_regex_release(inode, file, 0);
1538 }
1539
1540 static struct file_operations ftrace_avail_fops = {
1541         .open = ftrace_avail_open,
1542         .read = seq_read,
1543         .llseek = seq_lseek,
1544         .release = ftrace_avail_release,
1545 };
1546
1547 static struct file_operations ftrace_failures_fops = {
1548         .open = ftrace_failures_open,
1549         .read = seq_read,
1550         .llseek = seq_lseek,
1551         .release = ftrace_avail_release,
1552 };
1553
1554 static struct file_operations ftrace_filter_fops = {
1555         .open = ftrace_filter_open,
1556         .read = ftrace_regex_read,
1557         .write = ftrace_filter_write,
1558         .llseek = ftrace_regex_lseek,
1559         .release = ftrace_filter_release,
1560 };
1561
1562 static struct file_operations ftrace_notrace_fops = {
1563         .open = ftrace_notrace_open,
1564         .read = ftrace_regex_read,
1565         .write = ftrace_notrace_write,
1566         .llseek = ftrace_regex_lseek,
1567         .release = ftrace_notrace_release,
1568 };
1569
1570 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1571
1572 static DEFINE_MUTEX(graph_lock);
1573
1574 int ftrace_graph_count;
1575 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
1576
1577 static void *
1578 g_next(struct seq_file *m, void *v, loff_t *pos)
1579 {
1580         unsigned long *array = m->private;
1581         int index = *pos;
1582
1583         (*pos)++;
1584
1585         if (index >= ftrace_graph_count)
1586                 return NULL;
1587
1588         return &array[index];
1589 }
1590
1591 static void *g_start(struct seq_file *m, loff_t *pos)
1592 {
1593         void *p = NULL;
1594
1595         mutex_lock(&graph_lock);
1596
1597         p = g_next(m, p, pos);
1598
1599         return p;
1600 }
1601
1602 static void g_stop(struct seq_file *m, void *p)
1603 {
1604         mutex_unlock(&graph_lock);
1605 }
1606
1607 static int g_show(struct seq_file *m, void *v)
1608 {
1609         unsigned long *ptr = v;
1610         char str[KSYM_SYMBOL_LEN];
1611
1612         if (!ptr)
1613                 return 0;
1614
1615         kallsyms_lookup(*ptr, NULL, NULL, NULL, str);
1616
1617         seq_printf(m, "%s\n", str);
1618
1619         return 0;
1620 }
1621
1622 static struct seq_operations ftrace_graph_seq_ops = {
1623         .start = g_start,
1624         .next = g_next,
1625         .stop = g_stop,
1626         .show = g_show,
1627 };
1628
1629 static int
1630 ftrace_graph_open(struct inode *inode, struct file *file)
1631 {
1632         int ret = 0;
1633
1634         if (unlikely(ftrace_disabled))
1635                 return -ENODEV;
1636
1637         mutex_lock(&graph_lock);
1638         if ((file->f_mode & FMODE_WRITE) &&
1639             !(file->f_flags & O_APPEND)) {
1640                 ftrace_graph_count = 0;
1641                 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
1642         }
1643
1644         if (file->f_mode & FMODE_READ) {
1645                 ret = seq_open(file, &ftrace_graph_seq_ops);
1646                 if (!ret) {
1647                         struct seq_file *m = file->private_data;
1648                         m->private = ftrace_graph_funcs;
1649                 }
1650         } else
1651                 file->private_data = ftrace_graph_funcs;
1652         mutex_unlock(&graph_lock);
1653
1654         return ret;
1655 }
1656
1657 static ssize_t
1658 ftrace_graph_read(struct file *file, char __user *ubuf,
1659                        size_t cnt, loff_t *ppos)
1660 {
1661         if (file->f_mode & FMODE_READ)
1662                 return seq_read(file, ubuf, cnt, ppos);
1663         else
1664                 return -EPERM;
1665 }
1666
1667 static int
1668 ftrace_set_func(unsigned long *array, int idx, char *buffer)
1669 {
1670         char str[KSYM_SYMBOL_LEN];
1671         struct dyn_ftrace *rec;
1672         struct ftrace_page *pg;
1673         int found = 0;
1674         int j;
1675
1676         if (ftrace_disabled)
1677                 return -ENODEV;
1678
1679         /* should not be called from interrupt context */
1680         spin_lock(&ftrace_lock);
1681
1682         do_for_each_ftrace_rec(pg, rec) {
1683
1684                 if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
1685                         continue;
1686
1687                 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1688                 if (strcmp(str, buffer) == 0) {
1689                         /* Return 1 if we add it to the array */
1690                         found = 1;
1691                         for (j = 0; j < idx; j++)
1692                                 if (array[j] == rec->ip) {
1693                                         found = 0;
1694                                         break;
1695                                 }
1696                         if (found)
1697                                 array[idx] = rec->ip;
1698                         goto out;
1699                 }
1700         } while_for_each_ftrace_rec();
1701  out:
1702         spin_unlock(&ftrace_lock);
1703
1704         return found ? 0 : -EINVAL;
1705 }
1706
1707 static ssize_t
1708 ftrace_graph_write(struct file *file, const char __user *ubuf,
1709                    size_t cnt, loff_t *ppos)
1710 {
1711         unsigned char buffer[FTRACE_BUFF_MAX+1];
1712         unsigned long *array;
1713         size_t read = 0;
1714         ssize_t ret;
1715         int index = 0;
1716         char ch;
1717
1718         if (!cnt || cnt < 0)
1719                 return 0;
1720
1721         mutex_lock(&graph_lock);
1722
1723         if (ftrace_graph_count >= FTRACE_GRAPH_MAX_FUNCS) {
1724                 ret = -EBUSY;
1725                 goto out;
1726         }
1727
1728         if (file->f_mode & FMODE_READ) {
1729                 struct seq_file *m = file->private_data;
1730                 array = m->private;
1731         } else
1732                 array = file->private_data;
1733
1734         ret = get_user(ch, ubuf++);
1735         if (ret)
1736                 goto out;
1737         read++;
1738         cnt--;
1739
1740         /* skip white space */
1741         while (cnt && isspace(ch)) {
1742                 ret = get_user(ch, ubuf++);
1743                 if (ret)
1744                         goto out;
1745                 read++;
1746                 cnt--;
1747         }
1748
1749         if (isspace(ch)) {
1750                 *ppos += read;
1751                 ret = read;
1752                 goto out;
1753         }
1754
1755         while (cnt && !isspace(ch)) {
1756                 if (index < FTRACE_BUFF_MAX)
1757                         buffer[index++] = ch;
1758                 else {
1759                         ret = -EINVAL;
1760                         goto out;
1761                 }
1762                 ret = get_user(ch, ubuf++);
1763                 if (ret)
1764                         goto out;
1765                 read++;
1766                 cnt--;
1767         }
1768         buffer[index] = 0;
1769
1770         /* we allow only one at a time */
1771         ret = ftrace_set_func(array, ftrace_graph_count, buffer);
1772         if (ret)
1773                 goto out;
1774
1775         ftrace_graph_count++;
1776
1777         file->f_pos += read;
1778
1779         ret = read;
1780  out:
1781         mutex_unlock(&graph_lock);
1782
1783         return ret;
1784 }
1785
1786 static const struct file_operations ftrace_graph_fops = {
1787         .open = ftrace_graph_open,
1788         .read = ftrace_graph_read,
1789         .write = ftrace_graph_write,
1790 };
1791 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1792
1793 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
1794 {
1795         struct dentry *entry;
1796
1797         entry = debugfs_create_file("available_filter_functions", 0444,
1798                                     d_tracer, NULL, &ftrace_avail_fops);
1799         if (!entry)
1800                 pr_warning("Could not create debugfs "
1801                            "'available_filter_functions' entry\n");
1802
1803         entry = debugfs_create_file("failures", 0444,
1804                                     d_tracer, NULL, &ftrace_failures_fops);
1805         if (!entry)
1806                 pr_warning("Could not create debugfs 'failures' entry\n");
1807
1808         entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer,
1809                                     NULL, &ftrace_filter_fops);
1810         if (!entry)
1811                 pr_warning("Could not create debugfs "
1812                            "'set_ftrace_filter' entry\n");
1813
1814         entry = debugfs_create_file("set_ftrace_notrace", 0644, d_tracer,
1815                                     NULL, &ftrace_notrace_fops);
1816         if (!entry)
1817                 pr_warning("Could not create debugfs "
1818                            "'set_ftrace_notrace' entry\n");
1819
1820 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1821         entry = debugfs_create_file("set_graph_function", 0444, d_tracer,
1822                                     NULL,
1823                                     &ftrace_graph_fops);
1824         if (!entry)
1825                 pr_warning("Could not create debugfs "
1826                            "'set_graph_function' entry\n");
1827 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1828
1829         return 0;
1830 }
1831
1832 static int ftrace_convert_nops(struct module *mod,
1833                                unsigned long *start,
1834                                unsigned long *end)
1835 {
1836         unsigned long *p;
1837         unsigned long addr;
1838         unsigned long flags;
1839
1840         mutex_lock(&ftrace_start_lock);
1841         p = start;
1842         while (p < end) {
1843                 addr = ftrace_call_adjust(*p++);
1844                 /*
1845                  * Some architecture linkers will pad between
1846                  * the different mcount_loc sections of different
1847                  * object files to satisfy alignments.
1848                  * Skip any NULL pointers.
1849                  */
1850                 if (!addr)
1851                         continue;
1852                 ftrace_record_ip(addr);
1853         }
1854
1855         /* disable interrupts to prevent kstop machine */
1856         local_irq_save(flags);
1857         ftrace_update_code(mod);
1858         local_irq_restore(flags);
1859         mutex_unlock(&ftrace_start_lock);
1860
1861         return 0;
1862 }
1863
1864 void ftrace_init_module(struct module *mod,
1865                         unsigned long *start, unsigned long *end)
1866 {
1867         if (ftrace_disabled || start == end)
1868                 return;
1869         ftrace_convert_nops(mod, start, end);
1870 }
1871
1872 extern unsigned long __start_mcount_loc[];
1873 extern unsigned long __stop_mcount_loc[];
1874
1875 void __init ftrace_init(void)
1876 {
1877         unsigned long count, addr, flags;
1878         int ret;
1879
1880         /* Keep the ftrace pointer to the stub */
1881         addr = (unsigned long)ftrace_stub;
1882
1883         local_irq_save(flags);
1884         ftrace_dyn_arch_init(&addr);
1885         local_irq_restore(flags);
1886
1887         /* ftrace_dyn_arch_init places the return code in addr */
1888         if (addr)
1889                 goto failed;
1890
1891         count = __stop_mcount_loc - __start_mcount_loc;
1892
1893         ret = ftrace_dyn_table_alloc(count);
1894         if (ret)
1895                 goto failed;
1896
1897         last_ftrace_enabled = ftrace_enabled = 1;
1898
1899         ret = ftrace_convert_nops(NULL,
1900                                   __start_mcount_loc,
1901                                   __stop_mcount_loc);
1902
1903         return;
1904  failed:
1905         ftrace_disabled = 1;
1906 }
1907
1908 #else
1909
1910 static int __init ftrace_nodyn_init(void)
1911 {
1912         ftrace_enabled = 1;
1913         return 0;
1914 }
1915 device_initcall(ftrace_nodyn_init);
1916
1917 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
1918 static inline void ftrace_startup_enable(int command) { }
1919 /* Keep as macros so we do not need to define the commands */
1920 # define ftrace_startup(command)        do { } while (0)
1921 # define ftrace_shutdown(command)       do { } while (0)
1922 # define ftrace_startup_sysctl()        do { } while (0)
1923 # define ftrace_shutdown_sysctl()       do { } while (0)
1924 #endif /* CONFIG_DYNAMIC_FTRACE */
1925
1926 static ssize_t
1927 ftrace_pid_read(struct file *file, char __user *ubuf,
1928                        size_t cnt, loff_t *ppos)
1929 {
1930         char buf[64];
1931         int r;
1932
1933         if (ftrace_pid_trace == ftrace_swapper_pid)
1934                 r = sprintf(buf, "swapper tasks\n");
1935         else if (ftrace_pid_trace)
1936                 r = sprintf(buf, "%u\n", pid_nr(ftrace_pid_trace));
1937         else
1938                 r = sprintf(buf, "no pid\n");
1939
1940         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1941 }
1942
1943 static void clear_ftrace_swapper(void)
1944 {
1945         struct task_struct *p;
1946         int cpu;
1947
1948         get_online_cpus();
1949         for_each_online_cpu(cpu) {
1950                 p = idle_task(cpu);
1951                 clear_tsk_trace_trace(p);
1952         }
1953         put_online_cpus();
1954 }
1955
1956 static void set_ftrace_swapper(void)
1957 {
1958         struct task_struct *p;
1959         int cpu;
1960
1961         get_online_cpus();
1962         for_each_online_cpu(cpu) {
1963                 p = idle_task(cpu);
1964                 set_tsk_trace_trace(p);
1965         }
1966         put_online_cpus();
1967 }
1968
1969 static void clear_ftrace_pid(struct pid *pid)
1970 {
1971         struct task_struct *p;
1972
1973         rcu_read_lock();
1974         do_each_pid_task(pid, PIDTYPE_PID, p) {
1975                 clear_tsk_trace_trace(p);
1976         } while_each_pid_task(pid, PIDTYPE_PID, p);
1977         rcu_read_unlock();
1978
1979         put_pid(pid);
1980 }
1981
1982 static void set_ftrace_pid(struct pid *pid)
1983 {
1984         struct task_struct *p;
1985
1986         rcu_read_lock();
1987         do_each_pid_task(pid, PIDTYPE_PID, p) {
1988                 set_tsk_trace_trace(p);
1989         } while_each_pid_task(pid, PIDTYPE_PID, p);
1990         rcu_read_unlock();
1991 }
1992
1993 static void clear_ftrace_pid_task(struct pid **pid)
1994 {
1995         if (*pid == ftrace_swapper_pid)
1996                 clear_ftrace_swapper();
1997         else
1998                 clear_ftrace_pid(*pid);
1999
2000         *pid = NULL;
2001 }
2002
2003 static void set_ftrace_pid_task(struct pid *pid)
2004 {
2005         if (pid == ftrace_swapper_pid)
2006                 set_ftrace_swapper();
2007         else
2008                 set_ftrace_pid(pid);
2009 }
2010
2011 static ssize_t
2012 ftrace_pid_write(struct file *filp, const char __user *ubuf,
2013                    size_t cnt, loff_t *ppos)
2014 {
2015         struct pid *pid;
2016         char buf[64];
2017         long val;
2018         int ret;
2019
2020         if (cnt >= sizeof(buf))
2021                 return -EINVAL;
2022
2023         if (copy_from_user(&buf, ubuf, cnt))
2024                 return -EFAULT;
2025
2026         buf[cnt] = 0;
2027
2028         ret = strict_strtol(buf, 10, &val);
2029         if (ret < 0)
2030                 return ret;
2031
2032         mutex_lock(&ftrace_start_lock);
2033         if (val < 0) {
2034                 /* disable pid tracing */
2035                 if (!ftrace_pid_trace)
2036                         goto out;
2037
2038                 clear_ftrace_pid_task(&ftrace_pid_trace);
2039
2040         } else {
2041                 /* swapper task is special */
2042                 if (!val) {
2043                         pid = ftrace_swapper_pid;
2044                         if (pid == ftrace_pid_trace)
2045                                 goto out;
2046                 } else {
2047                         pid = find_get_pid(val);
2048
2049                         if (pid == ftrace_pid_trace) {
2050                                 put_pid(pid);
2051                                 goto out;
2052                         }
2053                 }
2054
2055                 if (ftrace_pid_trace)
2056                         clear_ftrace_pid_task(&ftrace_pid_trace);
2057
2058                 if (!pid)
2059                         goto out;
2060
2061                 ftrace_pid_trace = pid;
2062
2063                 set_ftrace_pid_task(ftrace_pid_trace);
2064         }
2065
2066         /* update the function call */
2067         ftrace_update_pid_func();
2068         ftrace_startup_enable(0);
2069
2070  out:
2071         mutex_unlock(&ftrace_start_lock);
2072
2073         return cnt;
2074 }
2075
2076 static struct file_operations ftrace_pid_fops = {
2077         .read = ftrace_pid_read,
2078         .write = ftrace_pid_write,
2079 };
2080
2081 static __init int ftrace_init_debugfs(void)
2082 {
2083         struct dentry *d_tracer;
2084         struct dentry *entry;
2085
2086         d_tracer = tracing_init_dentry();
2087         if (!d_tracer)
2088                 return 0;
2089
2090         ftrace_init_dyn_debugfs(d_tracer);
2091
2092         entry = debugfs_create_file("set_ftrace_pid", 0644, d_tracer,
2093                                     NULL, &ftrace_pid_fops);
2094         if (!entry)
2095                 pr_warning("Could not create debugfs "
2096                            "'set_ftrace_pid' entry\n");
2097         return 0;
2098 }
2099
2100 fs_initcall(ftrace_init_debugfs);
2101
2102 /**
2103  * ftrace_kill - kill ftrace
2104  *
2105  * This function should be used by panic code. It stops ftrace
2106  * but in a not so nice way. If you need to simply kill ftrace
2107  * from a non-atomic section, use ftrace_kill.
2108  */
2109 void ftrace_kill(void)
2110 {
2111         ftrace_disabled = 1;
2112         ftrace_enabled = 0;
2113         clear_ftrace_function();
2114 }
2115
2116 /**
2117  * register_ftrace_function - register a function for profiling
2118  * @ops - ops structure that holds the function for profiling.
2119  *
2120  * Register a function to be called by all functions in the
2121  * kernel.
2122  *
2123  * Note: @ops->func and all the functions it calls must be labeled
2124  *       with "notrace", otherwise it will go into a
2125  *       recursive loop.
2126  */
2127 int register_ftrace_function(struct ftrace_ops *ops)
2128 {
2129         int ret;
2130
2131         if (unlikely(ftrace_disabled))
2132                 return -1;
2133
2134         mutex_lock(&ftrace_sysctl_lock);
2135
2136         ret = __register_ftrace_function(ops);
2137         ftrace_startup(0);
2138
2139         mutex_unlock(&ftrace_sysctl_lock);
2140         return ret;
2141 }
2142
2143 /**
2144  * unregister_ftrace_function - unregister a function for profiling.
2145  * @ops - ops structure that holds the function to unregister
2146  *
2147  * Unregister a function that was added to be called by ftrace profiling.
2148  */
2149 int unregister_ftrace_function(struct ftrace_ops *ops)
2150 {
2151         int ret;
2152
2153         mutex_lock(&ftrace_sysctl_lock);
2154         ret = __unregister_ftrace_function(ops);
2155         ftrace_shutdown(0);
2156         mutex_unlock(&ftrace_sysctl_lock);
2157
2158         return ret;
2159 }
2160
2161 int
2162 ftrace_enable_sysctl(struct ctl_table *table, int write,
2163                      struct file *file, void __user *buffer, size_t *lenp,
2164                      loff_t *ppos)
2165 {
2166         int ret;
2167
2168         if (unlikely(ftrace_disabled))
2169                 return -ENODEV;
2170
2171         mutex_lock(&ftrace_sysctl_lock);
2172
2173         ret  = proc_dointvec(table, write, file, buffer, lenp, ppos);
2174
2175         if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
2176                 goto out;
2177
2178         last_ftrace_enabled = ftrace_enabled;
2179
2180         if (ftrace_enabled) {
2181
2182                 ftrace_startup_sysctl();
2183
2184                 /* we are starting ftrace again */
2185                 if (ftrace_list != &ftrace_list_end) {
2186                         if (ftrace_list->next == &ftrace_list_end)
2187                                 ftrace_trace_function = ftrace_list->func;
2188                         else
2189                                 ftrace_trace_function = ftrace_list_func;
2190                 }
2191
2192         } else {
2193                 /* stopping ftrace calls (just send to ftrace_stub) */
2194                 ftrace_trace_function = ftrace_stub;
2195
2196                 ftrace_shutdown_sysctl();
2197         }
2198
2199  out:
2200         mutex_unlock(&ftrace_sysctl_lock);
2201         return ret;
2202 }
2203
2204 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2205
2206 static atomic_t ftrace_graph_active;
2207 static struct notifier_block ftrace_suspend_notifier;
2208
2209 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
2210 {
2211         return 0;
2212 }
2213
2214 /* The callbacks that hook a function */
2215 trace_func_graph_ret_t ftrace_graph_return =
2216                         (trace_func_graph_ret_t)ftrace_stub;
2217 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
2218
2219 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
2220 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
2221 {
2222         int i;
2223         int ret = 0;
2224         unsigned long flags;
2225         int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
2226         struct task_struct *g, *t;
2227
2228         for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
2229                 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
2230                                         * sizeof(struct ftrace_ret_stack),
2231                                         GFP_KERNEL);
2232                 if (!ret_stack_list[i]) {
2233                         start = 0;
2234                         end = i;
2235                         ret = -ENOMEM;
2236                         goto free;
2237                 }
2238         }
2239
2240         read_lock_irqsave(&tasklist_lock, flags);
2241         do_each_thread(g, t) {
2242                 if (start == end) {
2243                         ret = -EAGAIN;
2244                         goto unlock;
2245                 }
2246
2247                 if (t->ret_stack == NULL) {
2248                         t->curr_ret_stack = -1;
2249                         /* Make sure IRQs see the -1 first: */
2250                         barrier();
2251                         t->ret_stack = ret_stack_list[start++];
2252                         atomic_set(&t->tracing_graph_pause, 0);
2253                         atomic_set(&t->trace_overrun, 0);
2254                 }
2255         } while_each_thread(g, t);
2256
2257 unlock:
2258         read_unlock_irqrestore(&tasklist_lock, flags);
2259 free:
2260         for (i = start; i < end; i++)
2261                 kfree(ret_stack_list[i]);
2262         return ret;
2263 }
2264
2265 /* Allocate a return stack for each task */
2266 static int start_graph_tracing(void)
2267 {
2268         struct ftrace_ret_stack **ret_stack_list;
2269         int ret;
2270
2271         ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
2272                                 sizeof(struct ftrace_ret_stack *),
2273                                 GFP_KERNEL);
2274
2275         if (!ret_stack_list)
2276                 return -ENOMEM;
2277
2278         do {
2279                 ret = alloc_retstack_tasklist(ret_stack_list);
2280         } while (ret == -EAGAIN);
2281
2282         kfree(ret_stack_list);
2283         return ret;
2284 }
2285
2286 /*
2287  * Hibernation protection.
2288  * The state of the current task is too much unstable during
2289  * suspend/restore to disk. We want to protect against that.
2290  */
2291 static int
2292 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
2293                                                         void *unused)
2294 {
2295         switch (state) {
2296         case PM_HIBERNATION_PREPARE:
2297                 pause_graph_tracing();
2298                 break;
2299
2300         case PM_POST_HIBERNATION:
2301                 unpause_graph_tracing();
2302                 break;
2303         }
2304         return NOTIFY_DONE;
2305 }
2306
2307 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
2308                         trace_func_graph_ent_t entryfunc)
2309 {
2310         int ret = 0;
2311
2312         mutex_lock(&ftrace_sysctl_lock);
2313
2314         ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
2315         register_pm_notifier(&ftrace_suspend_notifier);
2316
2317         atomic_inc(&ftrace_graph_active);
2318         ret = start_graph_tracing();
2319         if (ret) {
2320                 atomic_dec(&ftrace_graph_active);
2321                 goto out;
2322         }
2323
2324         ftrace_graph_return = retfunc;
2325         ftrace_graph_entry = entryfunc;
2326
2327         ftrace_startup(FTRACE_START_FUNC_RET);
2328
2329 out:
2330         mutex_unlock(&ftrace_sysctl_lock);
2331         return ret;
2332 }
2333
2334 void unregister_ftrace_graph(void)
2335 {
2336         mutex_lock(&ftrace_sysctl_lock);
2337
2338         atomic_dec(&ftrace_graph_active);
2339         ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
2340         ftrace_graph_entry = ftrace_graph_entry_stub;
2341         ftrace_shutdown(FTRACE_STOP_FUNC_RET);
2342         unregister_pm_notifier(&ftrace_suspend_notifier);
2343
2344         mutex_unlock(&ftrace_sysctl_lock);
2345 }
2346
2347 /* Allocate a return stack for newly created task */
2348 void ftrace_graph_init_task(struct task_struct *t)
2349 {
2350         if (atomic_read(&ftrace_graph_active)) {
2351                 t->ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
2352                                 * sizeof(struct ftrace_ret_stack),
2353                                 GFP_KERNEL);
2354                 if (!t->ret_stack)
2355                         return;
2356                 t->curr_ret_stack = -1;
2357                 atomic_set(&t->tracing_graph_pause, 0);
2358                 atomic_set(&t->trace_overrun, 0);
2359         } else
2360                 t->ret_stack = NULL;
2361 }
2362
2363 void ftrace_graph_exit_task(struct task_struct *t)
2364 {
2365         struct ftrace_ret_stack *ret_stack = t->ret_stack;
2366
2367         t->ret_stack = NULL;
2368         /* NULL must become visible to IRQs before we free it: */
2369         barrier();
2370
2371         kfree(ret_stack);
2372 }
2373
2374 void ftrace_graph_stop(void)
2375 {
2376         ftrace_stop();
2377 }
2378 #endif
2379