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 #include <linux/hash.h>
  31
  32 #include <asm/ftrace.h>
  33
  34 #include "trace.h"
  35
  36 #define FTRACE_WARN_ON(cond)                    \
  37         do {                                    \
  38                 if (WARN_ON(cond))              \
  39                         ftrace_kill();          \
  40         } while (0)
  41
  42 #define FTRACE_WARN_ON_ONCE(cond)               \
  43         do {                                    \
  44                 if (WARN_ON_ONCE(cond))         \
  45                         ftrace_kill();          \
  46         } while (0)
  47
  48 /* hash bits for specific function selection */
  49 #define FTRACE_HASH_BITS 7
  50 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
  51
  52 /* ftrace_enabled is a method to turn ftrace on or off */
  53 int ftrace_enabled __read_mostly;
  54 static int last_ftrace_enabled;
  55
  56 /* Quick disabling of function tracer. */
  57 int function_trace_stop;
  58
  59 /*
  60  * ftrace_disabled is set when an anomaly is discovered.
  61  * ftrace_disabled is much stronger than ftrace_enabled.
  62  */
  63 static int ftrace_disabled __read_mostly;
  64
  65 static DEFINE_MUTEX(ftrace_lock);
  66
  67 static struct ftrace_ops ftrace_list_end __read_mostly =
  68 {
  69         .func = ftrace_stub,
  70 };
  71
  72 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
  73 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
  74 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
  75 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
  76
  77 static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
  78 {
  79         struct ftrace_ops *op = ftrace_list;
  80
  81         /* in case someone actually ports this to alpha! */
  82         read_barrier_depends();
  83
  84         while (op != &ftrace_list_end) {
  85                 /* silly alpha */
  86                 read_barrier_depends();
  87                 op->func(ip, parent_ip);
  88                 op = op->next;
  89         };
  90 }
  91
  92 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
  93 {
  94         if (!test_tsk_trace_trace(current))
  95                 return;
  96
  97         ftrace_pid_function(ip, parent_ip);
  98 }
  99
 100 static void set_ftrace_pid_function(ftrace_func_t func)
 101 {
 102         /* do not set ftrace_pid_function to itself! */
 103         if (func != ftrace_pid_func)
 104                 ftrace_pid_function = func;
 105 }
 106
 107 /**
 108  * clear_ftrace_function - reset the ftrace function
 109  *
 110  * This NULLs the ftrace function and in essence stops
 111  * tracing.  There may be lag
 112  */
 113 void clear_ftrace_function(void)
 114 {
 115         ftrace_trace_function = ftrace_stub;
 116         __ftrace_trace_function = ftrace_stub;
 117         ftrace_pid_function = ftrace_stub;
 118 }
 119
 120 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 121 /*
 122  * For those archs that do not test ftrace_trace_stop in their
 123  * mcount call site, we need to do it from C.
 124  */
 125 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
 126 {
 127         if (function_trace_stop)
 128                 return;
 129
 130         __ftrace_trace_function(ip, parent_ip);
 131 }
 132 #endif
 133
 134 static int __register_ftrace_function(struct ftrace_ops *ops)
 135 {
 136         ops->next = ftrace_list;
 137         /*
 138          * We are entering ops into the ftrace_list but another
 139          * CPU might be walking that list. We need to make sure
 140          * the ops->next pointer is valid before another CPU sees
 141          * the ops pointer included into the ftrace_list.
 142          */
 143         smp_wmb();
 144         ftrace_list = ops;
 145
 146         if (ftrace_enabled) {
 147                 ftrace_func_t func;
 148
 149                 if (ops->next == &ftrace_list_end)
 150                         func = ops->func;
 151                 else
 152                         func = ftrace_list_func;
 153
 154                 if (ftrace_pid_trace) {
 155                         set_ftrace_pid_function(func);
 156                         func = ftrace_pid_func;
 157                 }
 158
 159                 /*
 160                  * For one func, simply call it directly.
 161                  * For more than one func, call the chain.
 162                  */
 163 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 164                 ftrace_trace_function = func;
 165 #else
 166                 __ftrace_trace_function = func;
 167                 ftrace_trace_function = ftrace_test_stop_func;
 168 #endif
 169         }
 170
 171         return 0;
 172 }
 173
 174 static int __unregister_ftrace_function(struct ftrace_ops *ops)
 175 {
 176         struct ftrace_ops **p;
 177
 178         /*
 179          * If we are removing the last function, then simply point
 180          * to the ftrace_stub.
 181          */
 182         if (ftrace_list == ops && ops->next == &ftrace_list_end) {
 183                 ftrace_trace_function = ftrace_stub;
 184                 ftrace_list = &ftrace_list_end;
 185                 return 0;
 186         }
 187
 188         for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
 189                 if (*p == ops)
 190                         break;
 191
 192         if (*p != ops)
 193                 return -1;
 194
 195         *p = (*p)->next;
 196
 197         if (ftrace_enabled) {
 198                 /* If we only have one func left, then call that directly */
 199                 if (ftrace_list->next == &ftrace_list_end) {
 200                         ftrace_func_t func = ftrace_list->func;
 201
 202                         if (ftrace_pid_trace) {
 203                                 set_ftrace_pid_function(func);
 204                                 func = ftrace_pid_func;
 205                         }
 206 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 207                         ftrace_trace_function = func;
 208 #else
 209                         __ftrace_trace_function = func;
 210 #endif
 211                 }
 212         }
 213
 214         return 0;
 215 }
 216
 217 static void ftrace_update_pid_func(void)
 218 {
 219         ftrace_func_t func;
 220
 221         mutex_lock(&ftrace_lock);
 222
 223         if (ftrace_trace_function == ftrace_stub)
 224                 goto out;
 225
 226         func = ftrace_trace_function;
 227
 228         if (ftrace_pid_trace) {
 229                 set_ftrace_pid_function(func);
 230                 func = ftrace_pid_func;
 231         } else {
 232                 if (func == ftrace_pid_func)
 233                         func = ftrace_pid_function;
 234         }
 235
 236 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 237         ftrace_trace_function = func;
 238 #else
 239         __ftrace_trace_function = func;
 240 #endif
 241
 242  out:
 243         mutex_unlock(&ftrace_lock);
 244 }
 245
 246 /* set when tracing only a pid */
 247 struct pid *ftrace_pid_trace;
 248 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
 249
 250 #ifdef CONFIG_DYNAMIC_FTRACE
 251
 252 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
 253 # error Dynamic ftrace depends on MCOUNT_RECORD
 254 #endif
 255
 256 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
 257
 258 struct ftrace_func_probe {
 259         struct hlist_node       node;
 260         struct ftrace_probe_ops *ops;
 261         unsigned long           flags;
 262         unsigned long           ip;
 263         void                    *data;
 264         struct rcu_head         rcu;
 265 };
 266
 267
 268 enum {
 269         FTRACE_ENABLE_CALLS             = (1 << 0),
 270         FTRACE_DISABLE_CALLS            = (1 << 1),
 271         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 272         FTRACE_ENABLE_MCOUNT            = (1 << 3),
 273         FTRACE_DISABLE_MCOUNT           = (1 << 4),
 274         FTRACE_START_FUNC_RET           = (1 << 5),
 275         FTRACE_STOP_FUNC_RET            = (1 << 6),
 276 };
 277
 278 static int ftrace_filtered;
 279
 280 static LIST_HEAD(ftrace_new_addrs);
 281
 282 static DEFINE_MUTEX(ftrace_regex_lock);
 283
 284 struct ftrace_page {
 285         struct ftrace_page      *next;
 286         int                     index;
 287         struct dyn_ftrace       records[];
 288 };
 289
 290 #define ENTRIES_PER_PAGE \
 291   ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
 292
 293 /* estimate from running different kernels */
 294 #define NR_TO_INIT              10000
 295
 296 static struct ftrace_page       *ftrace_pages_start;
 297 static struct ftrace_page       *ftrace_pages;
 298
 299 static struct dyn_ftrace *ftrace_free_records;
 300
 301 /*
 302  * This is a double for. Do not use 'break' to break out of the loop,
 303  * you must use a goto.
 304  */
 305 #define do_for_each_ftrace_rec(pg, rec)                                 \
 306         for (pg = ftrace_pages_start; pg; pg = pg->next) {              \
 307                 int _____i;                                             \
 308                 for (_____i = 0; _____i < pg->index; _____i++) {        \
 309                         rec = &pg->records[_____i];
 310
 311 #define while_for_each_ftrace_rec()             \
 312                 }                               \
 313         }
 314
 315 #ifdef CONFIG_KPROBES
 316
 317 static int frozen_record_count;
 318
 319 static inline void freeze_record(struct dyn_ftrace *rec)
 320 {
 321         if (!(rec->flags & FTRACE_FL_FROZEN)) {
 322                 rec->flags |= FTRACE_FL_FROZEN;
 323                 frozen_record_count++;
 324         }
 325 }
 326
 327 static inline void unfreeze_record(struct dyn_ftrace *rec)
 328 {
 329         if (rec->flags & FTRACE_FL_FROZEN) {
 330                 rec->flags &= ~FTRACE_FL_FROZEN;
 331                 frozen_record_count--;
 332         }
 333 }
 334
 335 static inline int record_frozen(struct dyn_ftrace *rec)
 336 {
 337         return rec->flags & FTRACE_FL_FROZEN;
 338 }
 339 #else
 340 # define freeze_record(rec)                     ({ 0; })
 341 # define unfreeze_record(rec)                   ({ 0; })
 342 # define record_frozen(rec)                     ({ 0; })
 343 #endif /* CONFIG_KPROBES */
 344
 345 static void ftrace_free_rec(struct dyn_ftrace *rec)
 346 {
 347         rec->ip = (unsigned long)ftrace_free_records;
 348         ftrace_free_records = rec;
 349         rec->flags |= FTRACE_FL_FREE;
 350 }
 351
 352 void ftrace_release(void *start, unsigned long size)
 353 {
 354         struct dyn_ftrace *rec;
 355         struct ftrace_page *pg;
 356         unsigned long s = (unsigned long)start;
 357         unsigned long e = s + size;
 358
 359         if (ftrace_disabled || !start)
 360                 return;
 361
 362         mutex_lock(&ftrace_lock);
 363         do_for_each_ftrace_rec(pg, rec) {
 364                 if ((rec->ip >= s) && (rec->ip < e))
 365                         ftrace_free_rec(rec);
 366         } while_for_each_ftrace_rec();
 367         mutex_unlock(&ftrace_lock);
 368 }
 369
 370 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
 371 {
 372         struct dyn_ftrace *rec;
 373
 374         /* First check for freed records */
 375         if (ftrace_free_records) {
 376                 rec = ftrace_free_records;
 377
 378                 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
 379                         FTRACE_WARN_ON_ONCE(1);
 380                         ftrace_free_records = NULL;
 381                         return NULL;
 382                 }
 383
 384                 ftrace_free_records = (void *)rec->ip;
 385                 memset(rec, 0, sizeof(*rec));
 386                 return rec;
 387         }
 388
 389         if (ftrace_pages->index == ENTRIES_PER_PAGE) {
 390                 if (!ftrace_pages->next) {
 391                         /* allocate another page */
 392                         ftrace_pages->next =
 393                                 (void *)get_zeroed_page(GFP_KERNEL);
 394                         if (!ftrace_pages->next)
 395                                 return NULL;
 396                 }
 397                 ftrace_pages = ftrace_pages->next;
 398         }
 399
 400         return &ftrace_pages->records[ftrace_pages->index++];
 401 }
 402
 403 static struct dyn_ftrace *
 404 ftrace_record_ip(unsigned long ip)
 405 {
 406         struct dyn_ftrace *rec;
 407
 408         if (ftrace_disabled)
 409                 return NULL;
 410
 411         rec = ftrace_alloc_dyn_node(ip);
 412         if (!rec)
 413                 return NULL;
 414
 415         rec->ip = ip;
 416
 417         list_add(&rec->list, &ftrace_new_addrs);
 418
 419         return rec;
 420 }
 421
 422 static void print_ip_ins(const char *fmt, unsigned char *p)
 423 {
 424         int i;
 425
 426         printk(KERN_CONT "%s", fmt);
 427
 428         for (i = 0; i < MCOUNT_INSN_SIZE; i++)
 429                 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
 430 }
 431
 432 static void ftrace_bug(int failed, unsigned long ip)
 433 {
 434         switch (failed) {
 435         case -EFAULT:
 436                 FTRACE_WARN_ON_ONCE(1);
 437                 pr_info("ftrace faulted on modifying ");
 438                 print_ip_sym(ip);
 439                 break;
 440         case -EINVAL:
 441                 FTRACE_WARN_ON_ONCE(1);
 442                 pr_info("ftrace failed to modify ");
 443                 print_ip_sym(ip);
 444                 print_ip_ins(" actual: ", (unsigned char *)ip);
 445                 printk(KERN_CONT "\n");
 446                 break;
 447         case -EPERM:
 448                 FTRACE_WARN_ON_ONCE(1);
 449                 pr_info("ftrace faulted on writing ");
 450                 print_ip_sym(ip);
 451                 break;
 452         default:
 453                 FTRACE_WARN_ON_ONCE(1);
 454                 pr_info("ftrace faulted on unknown error ");
 455                 print_ip_sym(ip);
 456         }
 457 }
 458
 459
 460 static int
 461 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
 462 {
 463         unsigned long ftrace_addr;
 464         unsigned long ip, fl;
 465
 466         ftrace_addr = (unsigned long)FTRACE_ADDR;
 467
 468         ip = rec->ip;
 469
 470         /*
 471          * If this record is not to be traced and
 472          * it is not enabled then do nothing.
 473          *
 474          * If this record is not to be traced and
 475          * it is enabled then disable it.
 476          *
 477          */
 478         if (rec->flags & FTRACE_FL_NOTRACE) {
 479                 if (rec->flags & FTRACE_FL_ENABLED)
 480                         rec->flags &= ~FTRACE_FL_ENABLED;
 481                 else
 482                         return 0;
 483
 484         } else if (ftrace_filtered && enable) {
 485                 /*
 486                  * Filtering is on:
 487                  */
 488
 489                 fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED);
 490
 491                 /* Record is filtered and enabled, do nothing */
 492                 if (fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED))
 493                         return 0;
 494
 495                 /* Record is not filtered or enabled, do nothing */
 496                 if (!fl)
 497                         return 0;
 498
 499                 /* Record is not filtered but enabled, disable it */
 500                 if (fl == FTRACE_FL_ENABLED)
 501                         rec->flags &= ~FTRACE_FL_ENABLED;
 502                 else
 503                 /* Otherwise record is filtered but not enabled, enable it */
 504                         rec->flags |= FTRACE_FL_ENABLED;
 505         } else {
 506                 /* Disable or not filtered */
 507
 508                 if (enable) {
 509                         /* if record is enabled, do nothing */
 510                         if (rec->flags & FTRACE_FL_ENABLED)
 511                                 return 0;
 512
 513                         rec->flags |= FTRACE_FL_ENABLED;
 514
 515                 } else {
 516
 517                         /* if record is not enabled, do nothing */
 518                         if (!(rec->flags & FTRACE_FL_ENABLED))
 519                                 return 0;
 520
 521                         rec->flags &= ~FTRACE_FL_ENABLED;
 522                 }
 523         }
 524
 525         if (rec->flags & FTRACE_FL_ENABLED)
 526                 return ftrace_make_call(rec, ftrace_addr);
 527         else
 528                 return ftrace_make_nop(NULL, rec, ftrace_addr);
 529 }
 530
 531 static void ftrace_replace_code(int enable)
 532 {
 533         struct dyn_ftrace *rec;
 534         struct ftrace_page *pg;
 535         int failed;
 536
 537         do_for_each_ftrace_rec(pg, rec) {
 538                 /*
 539                  * Skip over free records and records that have
 540                  * failed.
 541                  */
 542                 if (rec->flags & FTRACE_FL_FREE ||
 543                     rec->flags & FTRACE_FL_FAILED)
 544                         continue;
 545
 546                 /* ignore updates to this record's mcount site */
 547                 if (get_kprobe((void *)rec->ip)) {
 548                         freeze_record(rec);
 549                         continue;
 550                 } else {
 551                         unfreeze_record(rec);
 552                 }
 553
 554                 failed = __ftrace_replace_code(rec, enable);
 555                 if (failed && (rec->flags & FTRACE_FL_CONVERTED)) {
 556                         rec->flags |= FTRACE_FL_FAILED;
 557                         if ((system_state == SYSTEM_BOOTING) ||
 558                             !core_kernel_text(rec->ip)) {
 559                                 ftrace_free_rec(rec);
 560                         } else
 561                                 ftrace_bug(failed, rec->ip);
 562                 }
 563         } while_for_each_ftrace_rec();
 564 }
 565
 566 static int
 567 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
 568 {
 569         unsigned long ip;
 570         int ret;
 571
 572         ip = rec->ip;
 573
 574         ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
 575         if (ret) {
 576                 ftrace_bug(ret, ip);
 577                 rec->flags |= FTRACE_FL_FAILED;
 578                 return 0;
 579         }
 580         return 1;
 581 }
 582
 583 static int __ftrace_modify_code(void *data)
 584 {
 585         int *command = data;
 586
 587         if (*command & FTRACE_ENABLE_CALLS)
 588                 ftrace_replace_code(1);
 589         else if (*command & FTRACE_DISABLE_CALLS)
 590                 ftrace_replace_code(0);
 591
 592         if (*command & FTRACE_UPDATE_TRACE_FUNC)
 593                 ftrace_update_ftrace_func(ftrace_trace_function);
 594
 595         if (*command & FTRACE_START_FUNC_RET)
 596                 ftrace_enable_ftrace_graph_caller();
 597         else if (*command & FTRACE_STOP_FUNC_RET)
 598                 ftrace_disable_ftrace_graph_caller();
 599
 600         return 0;
 601 }
 602
 603 static void ftrace_run_update_code(int command)
 604 {
 605         stop_machine(__ftrace_modify_code, &command, NULL);
 606 }
 607
 608 static ftrace_func_t saved_ftrace_func;
 609 static int ftrace_start_up;
 610
 611 static void ftrace_startup_enable(int command)
 612 {
 613         if (saved_ftrace_func != ftrace_trace_function) {
 614                 saved_ftrace_func = ftrace_trace_function;
 615                 command |= FTRACE_UPDATE_TRACE_FUNC;
 616         }
 617
 618         if (!command || !ftrace_enabled)
 619                 return;
 620
 621         ftrace_run_update_code(command);
 622 }
 623
 624 static void ftrace_startup(int command)
 625 {
 626         if (unlikely(ftrace_disabled))
 627                 return;
 628
 629         ftrace_start_up++;
 630         command |= FTRACE_ENABLE_CALLS;
 631
 632         ftrace_startup_enable(command);
 633 }
 634
 635 static void ftrace_shutdown(int command)
 636 {
 637         if (unlikely(ftrace_disabled))
 638                 return;
 639
 640         ftrace_start_up--;
 641         if (!ftrace_start_up)
 642                 command |= FTRACE_DISABLE_CALLS;
 643
 644         if (saved_ftrace_func != ftrace_trace_function) {
 645                 saved_ftrace_func = ftrace_trace_function;
 646                 command |= FTRACE_UPDATE_TRACE_FUNC;
 647         }
 648
 649         if (!command || !ftrace_enabled)
 650                 return;
 651
 652         ftrace_run_update_code(command);
 653 }
 654
 655 static void ftrace_startup_sysctl(void)
 656 {
 657         int command = FTRACE_ENABLE_MCOUNT;
 658
 659         if (unlikely(ftrace_disabled))
 660                 return;
 661
 662         /* Force update next time */
 663         saved_ftrace_func = NULL;
 664         /* ftrace_start_up is true if we want ftrace running */
 665         if (ftrace_start_up)
 666                 command |= FTRACE_ENABLE_CALLS;
 667
 668         ftrace_run_update_code(command);
 669 }
 670
 671 static void ftrace_shutdown_sysctl(void)
 672 {
 673         int command = FTRACE_DISABLE_MCOUNT;
 674
 675         if (unlikely(ftrace_disabled))
 676                 return;
 677
 678         /* ftrace_start_up is true if ftrace is running */
 679         if (ftrace_start_up)
 680                 command |= FTRACE_DISABLE_CALLS;
 681
 682         ftrace_run_update_code(command);
 683 }
 684
 685 static cycle_t          ftrace_update_time;
 686 static unsigned long    ftrace_update_cnt;
 687 unsigned long           ftrace_update_tot_cnt;
 688
 689 static int ftrace_update_code(struct module *mod)
 690 {
 691         struct dyn_ftrace *p, *t;
 692         cycle_t start, stop;
 693
 694         start = ftrace_now(raw_smp_processor_id());
 695         ftrace_update_cnt = 0;
 696
 697         list_for_each_entry_safe(p, t, &ftrace_new_addrs, list) {
 698
 699                 /* If something went wrong, bail without enabling anything */
 700                 if (unlikely(ftrace_disabled))
 701                         return -1;
 702
 703                 list_del_init(&p->list);
 704
 705                 /* convert record (i.e, patch mcount-call with NOP) */
 706                 if (ftrace_code_disable(mod, p)) {
 707                         p->flags |= FTRACE_FL_CONVERTED;
 708                         ftrace_update_cnt++;
 709                 } else
 710                         ftrace_free_rec(p);
 711         }
 712
 713         stop = ftrace_now(raw_smp_processor_id());
 714         ftrace_update_time = stop - start;
 715         ftrace_update_tot_cnt += ftrace_update_cnt;
 716
 717         return 0;
 718 }
 719
 720 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
 721 {
 722         struct ftrace_page *pg;
 723         int cnt;
 724         int i;
 725
 726         /* allocate a few pages */
 727         ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
 728         if (!ftrace_pages_start)
 729                 return -1;
 730
 731         /*
 732          * Allocate a few more pages.
 733          *
 734          * TODO: have some parser search vmlinux before
 735          *   final linking to find all calls to ftrace.
 736          *   Then we can:
 737          *    a) know how many pages to allocate.
 738          *     and/or
 739          *    b) set up the table then.
 740          *
 741          *  The dynamic code is still necessary for
 742          *  modules.
 743          */
 744
 745         pg = ftrace_pages = ftrace_pages_start;
 746
 747         cnt = num_to_init / ENTRIES_PER_PAGE;
 748         pr_info("ftrace: allocating %ld entries in %d pages\n",
 749                 num_to_init, cnt + 1);
 750
 751         for (i = 0; i < cnt; i++) {
 752                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
 753
 754                 /* If we fail, we'll try later anyway */
 755                 if (!pg->next)
 756                         break;
 757
 758                 pg = pg->next;
 759         }
 760
 761         return 0;
 762 }
 763
 764 enum {
 765         FTRACE_ITER_FILTER      = (1 << 0),
 766         FTRACE_ITER_CONT        = (1 << 1),
 767         FTRACE_ITER_NOTRACE     = (1 << 2),
 768         FTRACE_ITER_FAILURES    = (1 << 3),
 769         FTRACE_ITER_PRINTALL    = (1 << 4),
 770         FTRACE_ITER_HASH        = (1 << 5),
 771 };
 772
 773 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
 774
 775 struct ftrace_iterator {
 776         struct ftrace_page      *pg;
 777         int                     hidx;
 778         int                     idx;
 779         unsigned                flags;
 780         unsigned char           buffer[FTRACE_BUFF_MAX+1];
 781         unsigned                buffer_idx;
 782         unsigned                filtered;
 783 };
 784
 785 static void *
 786 t_hash_next(struct seq_file *m, void *v, loff_t *pos)
 787 {
 788         struct ftrace_iterator *iter = m->private;
 789         struct hlist_node *hnd = v;
 790         struct hlist_head *hhd;
 791
 792         WARN_ON(!(iter->flags & FTRACE_ITER_HASH));
 793
 794         (*pos)++;
 795
 796  retry:
 797         if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
 798                 return NULL;
 799
 800         hhd = &ftrace_func_hash[iter->hidx];
 801
 802         if (hlist_empty(hhd)) {
 803                 iter->hidx++;
 804                 hnd = NULL;
 805                 goto retry;
 806         }
 807
 808         if (!hnd)
 809                 hnd = hhd->first;
 810         else {
 811                 hnd = hnd->next;
 812                 if (!hnd) {
 813                         iter->hidx++;
 814                         goto retry;
 815                 }
 816         }
 817
 818         return hnd;
 819 }
 820
 821 static void *t_hash_start(struct seq_file *m, loff_t *pos)
 822 {
 823         struct ftrace_iterator *iter = m->private;
 824         void *p = NULL;
 825
 826         iter->flags |= FTRACE_ITER_HASH;
 827
 828         return t_hash_next(m, p, pos);
 829 }
 830
 831 static int t_hash_show(struct seq_file *m, void *v)
 832 {
 833         struct ftrace_func_probe *rec;
 834         struct hlist_node *hnd = v;
 835         char str[KSYM_SYMBOL_LEN];
 836
 837         rec = hlist_entry(hnd, struct ftrace_func_probe, node);
 838
 839         if (rec->ops->print)
 840                 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
 841
 842         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 843         seq_printf(m, "%s:", str);
 844
 845         kallsyms_lookup((unsigned long)rec->ops->func, NULL, NULL, NULL, str);
 846         seq_printf(m, "%s", str);
 847
 848         if (rec->data)
 849                 seq_printf(m, ":%p", rec->data);
 850         seq_putc(m, '\n');
 851
 852         return 0;
 853 }
 854
 855 static void *
 856 t_next(struct seq_file *m, void *v, loff_t *pos)
 857 {
 858         struct ftrace_iterator *iter = m->private;
 859         struct dyn_ftrace *rec = NULL;
 860
 861         if (iter->flags & FTRACE_ITER_HASH)
 862                 return t_hash_next(m, v, pos);
 863
 864         (*pos)++;
 865
 866         if (iter->flags & FTRACE_ITER_PRINTALL)
 867                 return NULL;
 868
 869  retry:
 870         if (iter->idx >= iter->pg->index) {
 871                 if (iter->pg->next) {
 872                         iter->pg = iter->pg->next;
 873                         iter->idx = 0;
 874                         goto retry;
 875                 } else {
 876                         iter->idx = -1;
 877                 }
 878         } else {
 879                 rec = &iter->pg->records[iter->idx++];
 880                 if ((rec->flags & FTRACE_FL_FREE) ||
 881
 882                     (!(iter->flags & FTRACE_ITER_FAILURES) &&
 883                      (rec->flags & FTRACE_FL_FAILED)) ||
 884
 885                     ((iter->flags & FTRACE_ITER_FAILURES) &&
 886                      !(rec->flags & FTRACE_FL_FAILED)) ||
 887
 888                     ((iter->flags & FTRACE_ITER_FILTER) &&
 889                      !(rec->flags & FTRACE_FL_FILTER)) ||
 890
 891                     ((iter->flags & FTRACE_ITER_NOTRACE) &&
 892                      !(rec->flags & FTRACE_FL_NOTRACE))) {
 893                         rec = NULL;
 894                         goto retry;
 895                 }
 896         }
 897
 898         return rec;
 899 }
 900
 901 static void *t_start(struct seq_file *m, loff_t *pos)
 902 {
 903         struct ftrace_iterator *iter = m->private;
 904         void *p = NULL;
 905
 906         mutex_lock(&ftrace_lock);
 907         /*
 908          * For set_ftrace_filter reading, if we have the filter
 909          * off, we can short cut and just print out that all
 910          * functions are enabled.
 911          */
 912         if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) {
 913                 if (*pos > 0)
 914                         return t_hash_start(m, pos);
 915                 iter->flags |= FTRACE_ITER_PRINTALL;
 916                 (*pos)++;
 917                 return iter;
 918         }
 919
 920         if (iter->flags & FTRACE_ITER_HASH)
 921                 return t_hash_start(m, pos);
 922
 923         if (*pos > 0) {
 924                 if (iter->idx < 0)
 925                         return p;
 926                 (*pos)--;
 927                 iter->idx--;
 928         }
 929
 930         p = t_next(m, p, pos);
 931
 932         if (!p)
 933                 return t_hash_start(m, pos);
 934
 935         return p;
 936 }
 937
 938 static void t_stop(struct seq_file *m, void *p)
 939 {
 940         mutex_unlock(&ftrace_lock);
 941 }
 942
 943 static int t_show(struct seq_file *m, void *v)
 944 {
 945         struct ftrace_iterator *iter = m->private;
 946         struct dyn_ftrace *rec = v;
 947         char str[KSYM_SYMBOL_LEN];
 948
 949         if (iter->flags & FTRACE_ITER_HASH)
 950                 return t_hash_show(m, v);
 951
 952         if (iter->flags & FTRACE_ITER_PRINTALL) {
 953                 seq_printf(m, "#### all functions enabled ####\n");
 954                 return 0;
 955         }
 956
 957         if (!rec)
 958                 return 0;
 959
 960         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 961
 962         seq_printf(m, "%s\n", str);
 963
 964         return 0;
 965 }
 966
 967 static struct seq_operations show_ftrace_seq_ops = {
 968         .start = t_start,
 969         .next = t_next,
 970         .stop = t_stop,
 971         .show = t_show,
 972 };
 973
 974 static int
 975 ftrace_avail_open(struct inode *inode, struct file *file)
 976 {
 977         struct ftrace_iterator *iter;
 978         int ret;
 979
 980         if (unlikely(ftrace_disabled))
 981                 return -ENODEV;
 982
 983         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
 984         if (!iter)
 985                 return -ENOMEM;
 986
 987         iter->pg = ftrace_pages_start;
 988
 989         ret = seq_open(file, &show_ftrace_seq_ops);
 990         if (!ret) {
 991                 struct seq_file *m = file->private_data;
 992
 993                 m->private = iter;
 994         } else {
 995                 kfree(iter);
 996         }
 997
 998         return ret;
 999 }
1000
1001 int ftrace_avail_release(struct inode *inode, struct file *file)
1002 {
1003         struct seq_file *m = (struct seq_file *)file->private_data;
1004         struct ftrace_iterator *iter = m->private;
1005
1006         seq_release(inode, file);
1007         kfree(iter);
1008
1009         return 0;
1010 }
1011
1012 static int
1013 ftrace_failures_open(struct inode *inode, struct file *file)
1014 {
1015         int ret;
1016         struct seq_file *m;
1017         struct ftrace_iterator *iter;
1018
1019         ret = ftrace_avail_open(inode, file);
1020         if (!ret) {
1021                 m = (struct seq_file *)file->private_data;
1022                 iter = (struct ftrace_iterator *)m->private;
1023                 iter->flags = FTRACE_ITER_FAILURES;
1024         }
1025
1026         return ret;
1027 }
1028
1029
1030 static void ftrace_filter_reset(int enable)
1031 {
1032         struct ftrace_page *pg;
1033         struct dyn_ftrace *rec;
1034         unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1035
1036         mutex_lock(&ftrace_lock);
1037         if (enable)
1038                 ftrace_filtered = 0;
1039         do_for_each_ftrace_rec(pg, rec) {
1040                 if (rec->flags & FTRACE_FL_FAILED)
1041                         continue;
1042                 rec->flags &= ~type;
1043         } while_for_each_ftrace_rec();
1044         mutex_unlock(&ftrace_lock);
1045 }
1046
1047 static int
1048 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
1049 {
1050         struct ftrace_iterator *iter;
1051         int ret = 0;
1052
1053         if (unlikely(ftrace_disabled))
1054                 return -ENODEV;
1055
1056         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1057         if (!iter)
1058                 return -ENOMEM;
1059
1060         mutex_lock(&ftrace_regex_lock);
1061         if ((file->f_mode & FMODE_WRITE) &&
1062             !(file->f_flags & O_APPEND))
1063                 ftrace_filter_reset(enable);
1064
1065         if (file->f_mode & FMODE_READ) {
1066                 iter->pg = ftrace_pages_start;
1067                 iter->flags = enable ? FTRACE_ITER_FILTER :
1068                         FTRACE_ITER_NOTRACE;
1069
1070                 ret = seq_open(file, &show_ftrace_seq_ops);
1071                 if (!ret) {
1072                         struct seq_file *m = file->private_data;
1073                         m->private = iter;
1074                 } else
1075                         kfree(iter);
1076         } else
1077                 file->private_data = iter;
1078         mutex_unlock(&ftrace_regex_lock);
1079
1080         return ret;
1081 }
1082
1083 static int
1084 ftrace_filter_open(struct inode *inode, struct file *file)
1085 {
1086         return ftrace_regex_open(inode, file, 1);
1087 }
1088
1089 static int
1090 ftrace_notrace_open(struct inode *inode, struct file *file)
1091 {
1092         return ftrace_regex_open(inode, file, 0);
1093 }
1094
1095 static ssize_t
1096 ftrace_regex_read(struct file *file, char __user *ubuf,
1097                        size_t cnt, loff_t *ppos)
1098 {
1099         if (file->f_mode & FMODE_READ)
1100                 return seq_read(file, ubuf, cnt, ppos);
1101         else
1102                 return -EPERM;
1103 }
1104
1105 static loff_t
1106 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1107 {
1108         loff_t ret;
1109
1110         if (file->f_mode & FMODE_READ)
1111                 ret = seq_lseek(file, offset, origin);
1112         else
1113                 file->f_pos = ret = 1;
1114
1115         return ret;
1116 }
1117
1118 enum {
1119         MATCH_FULL,
1120         MATCH_FRONT_ONLY,
1121         MATCH_MIDDLE_ONLY,
1122         MATCH_END_ONLY,
1123 };
1124
1125 /*
1126  * (static function - no need for kernel doc)
1127  *
1128  * Pass in a buffer containing a glob and this function will
1129  * set search to point to the search part of the buffer and
1130  * return the type of search it is (see enum above).
1131  * This does modify buff.
1132  *
1133  * Returns enum type.
1134  *  search returns the pointer to use for comparison.
1135  *  not returns 1 if buff started with a '!'
1136  *     0 otherwise.
1137  */
1138 static int
1139 ftrace_setup_glob(char *buff, int len, char **search, int *not)
1140 {
1141         int type = MATCH_FULL;
1142         int i;
1143
1144         if (buff[0] == '!') {
1145                 *not = 1;
1146                 buff++;
1147                 len--;
1148         } else
1149                 *not = 0;
1150
1151         *search = buff;
1152
1153         for (i = 0; i < len; i++) {
1154                 if (buff[i] == '*') {
1155                         if (!i) {
1156                                 *search = buff + 1;
1157                                 type = MATCH_END_ONLY;
1158                         } else {
1159                                 if (type == MATCH_END_ONLY)
1160                                         type = MATCH_MIDDLE_ONLY;
1161                                 else
1162                                         type = MATCH_FRONT_ONLY;
1163                                 buff[i] = 0;
1164                                 break;
1165                         }
1166                 }
1167         }
1168
1169         return type;
1170 }
1171
1172 static int ftrace_match(char *str, char *regex, int len, int type)
1173 {
1174         int matched = 0;
1175         char *ptr;
1176
1177         switch (type) {
1178         case MATCH_FULL:
1179                 if (strcmp(str, regex) == 0)
1180                         matched = 1;
1181                 break;
1182         case MATCH_FRONT_ONLY:
1183                 if (strncmp(str, regex, len) == 0)
1184                         matched = 1;
1185                 break;
1186         case MATCH_MIDDLE_ONLY:
1187                 if (strstr(str, regex))
1188                         matched = 1;
1189                 break;
1190         case MATCH_END_ONLY:
1191                 ptr = strstr(str, regex);
1192                 if (ptr && (ptr[len] == 0))
1193                         matched = 1;
1194                 break;
1195         }
1196
1197         return matched;
1198 }
1199
1200 static int
1201 ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
1202 {
1203         char str[KSYM_SYMBOL_LEN];
1204
1205         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1206         return ftrace_match(str, regex, len, type);
1207 }
1208
1209 static void ftrace_match_records(char *buff, int len, int enable)
1210 {
1211         unsigned int search_len;
1212         struct ftrace_page *pg;
1213         struct dyn_ftrace *rec;
1214         unsigned long flag;
1215         char *search;
1216         int type;
1217         int not;
1218
1219         flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1220         type = ftrace_setup_glob(buff, len, &search, &not);
1221
1222         search_len = strlen(search);
1223
1224         mutex_lock(&ftrace_lock);
1225         do_for_each_ftrace_rec(pg, rec) {
1226
1227                 if (rec->flags & FTRACE_FL_FAILED)
1228                         continue;
1229
1230                 if (ftrace_match_record(rec, search, search_len, type)) {
1231                         if (not)
1232                                 rec->flags &= ~flag;
1233                         else
1234                                 rec->flags |= flag;
1235                 }
1236                 /*
1237                  * Only enable filtering if we have a function that
1238                  * is filtered on.
1239                  */
1240                 if (enable && (rec->flags & FTRACE_FL_FILTER))
1241                         ftrace_filtered = 1;
1242         } while_for_each_ftrace_rec();
1243         mutex_unlock(&ftrace_lock);
1244 }
1245
1246 static int
1247 ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
1248                            char *regex, int len, int type)
1249 {
1250         char str[KSYM_SYMBOL_LEN];
1251         char *modname;
1252
1253         kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
1254
1255         if (!modname || strcmp(modname, mod))
1256                 return 0;
1257
1258         /* blank search means to match all funcs in the mod */
1259         if (len)
1260                 return ftrace_match(str, regex, len, type);
1261         else
1262                 return 1;
1263 }
1264
1265 static void ftrace_match_module_records(char *buff, char *mod, int enable)
1266 {
1267         unsigned search_len = 0;
1268         struct ftrace_page *pg;
1269         struct dyn_ftrace *rec;
1270         int type = MATCH_FULL;
1271         char *search = buff;
1272         unsigned long flag;
1273         int not = 0;
1274
1275         flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1276
1277         /* blank or '*' mean the same */
1278         if (strcmp(buff, "*") == 0)
1279                 buff[0] = 0;
1280
1281         /* handle the case of 'dont filter this module' */
1282         if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
1283                 buff[0] = 0;
1284                 not = 1;
1285         }
1286
1287         if (strlen(buff)) {
1288                 type = ftrace_setup_glob(buff, strlen(buff), &search, &not);
1289                 search_len = strlen(search);
1290         }
1291
1292         mutex_lock(&ftrace_lock);
1293         do_for_each_ftrace_rec(pg, rec) {
1294
1295                 if (rec->flags & FTRACE_FL_FAILED)
1296                         continue;
1297
1298                 if (ftrace_match_module_record(rec, mod,
1299                                                search, search_len, type)) {
1300                         if (not)
1301                                 rec->flags &= ~flag;
1302                         else
1303                                 rec->flags |= flag;
1304                 }
1305                 if (enable && (rec->flags & FTRACE_FL_FILTER))
1306                         ftrace_filtered = 1;
1307
1308         } while_for_each_ftrace_rec();
1309         mutex_unlock(&ftrace_lock);
1310 }
1311
1312 /*
1313  * We register the module command as a template to show others how
1314  * to register the a command as well.
1315  */
1316
1317 static int
1318 ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
1319 {
1320         char *mod;
1321
1322         /*
1323          * cmd == 'mod' because we only registered this func
1324          * for the 'mod' ftrace_func_command.
1325          * But if you register one func with multiple commands,
1326          * you can tell which command was used by the cmd
1327          * parameter.
1328          */
1329
1330         /* we must have a module name */
1331         if (!param)
1332                 return -EINVAL;
1333
1334         mod = strsep(&param, ":");
1335         if (!strlen(mod))
1336                 return -EINVAL;
1337
1338         ftrace_match_module_records(func, mod, enable);
1339         return 0;
1340 }
1341
1342 static struct ftrace_func_command ftrace_mod_cmd = {
1343         .name                   = "mod",
1344         .func                   = ftrace_mod_callback,
1345 };
1346
1347 static int __init ftrace_mod_cmd_init(void)
1348 {
1349         return register_ftrace_command(&ftrace_mod_cmd);
1350 }
1351 device_initcall(ftrace_mod_cmd_init);
1352
1353 static void
1354 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
1355 {
1356         struct ftrace_func_probe *entry;
1357         struct hlist_head *hhd;
1358         struct hlist_node *n;
1359         unsigned long key;
1360         int resched;
1361
1362         key = hash_long(ip, FTRACE_HASH_BITS);
1363
1364         hhd = &ftrace_func_hash[key];
1365
1366         if (hlist_empty(hhd))
1367                 return;
1368
1369         /*
1370          * Disable preemption for these calls to prevent a RCU grace
1371          * period. This syncs the hash iteration and freeing of items
1372          * on the hash. rcu_read_lock is too dangerous here.
1373          */
1374         resched = ftrace_preempt_disable();
1375         hlist_for_each_entry_rcu(entry, n, hhd, node) {
1376                 if (entry->ip == ip)
1377                         entry->ops->func(ip, parent_ip, &entry->data);
1378         }
1379         ftrace_preempt_enable(resched);
1380 }
1381
1382 static struct ftrace_ops trace_probe_ops __read_mostly =
1383 {
1384         .func = function_trace_probe_call,
1385 };
1386
1387 static int ftrace_probe_registered;
1388
1389 static void __enable_ftrace_function_probe(void)
1390 {
1391         int i;
1392
1393         if (ftrace_probe_registered)
1394                 return;
1395
1396         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1397                 struct hlist_head *hhd = &ftrace_func_hash[i];
1398                 if (hhd->first)
1399                         break;
1400         }
1401         /* Nothing registered? */
1402         if (i == FTRACE_FUNC_HASHSIZE)
1403                 return;
1404
1405         __register_ftrace_function(&trace_probe_ops);
1406         ftrace_startup(0);
1407         ftrace_probe_registered = 1;
1408 }
1409
1410 static void __disable_ftrace_function_probe(void)
1411 {
1412         int i;
1413
1414         if (!ftrace_probe_registered)
1415                 return;
1416
1417         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1418                 struct hlist_head *hhd = &ftrace_func_hash[i];
1419                 if (hhd->first)
1420                         return;
1421         }
1422
1423         /* no more funcs left */
1424         __unregister_ftrace_function(&trace_probe_ops);
1425         ftrace_shutdown(0);
1426         ftrace_probe_registered = 0;
1427 }
1428
1429
1430 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
1431 {
1432         struct ftrace_func_probe *entry =
1433                 container_of(rhp, struct ftrace_func_probe, rcu);
1434
1435         if (entry->ops->free)
1436                 entry->ops->free(&entry->data);
1437         kfree(entry);
1438 }
1439
1440
1441 int
1442 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
1443                               void *data)
1444 {
1445         struct ftrace_func_probe *entry;
1446         struct ftrace_page *pg;
1447         struct dyn_ftrace *rec;
1448         int type, len, not;
1449         unsigned long key;
1450         int count = 0;
1451         char *search;
1452
1453         type = ftrace_setup_glob(glob, strlen(glob), &search, &not);
1454         len = strlen(search);
1455
1456         /* we do not support '!' for function probes */
1457         if (WARN_ON(not))
1458                 return -EINVAL;
1459
1460         mutex_lock(&ftrace_lock);
1461         do_for_each_ftrace_rec(pg, rec) {
1462
1463                 if (rec->flags & FTRACE_FL_FAILED)
1464                         continue;
1465
1466                 if (!ftrace_match_record(rec, search, len, type))
1467                         continue;
1468
1469                 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1470                 if (!entry) {
1471                         /* If we did not process any, then return error */
1472                         if (!count)
1473                                 count = -ENOMEM;
1474                         goto out_unlock;
1475                 }
1476
1477                 count++;
1478
1479                 entry->data = data;
1480
1481                 /*
1482                  * The caller might want to do something special
1483                  * for each function we find. We call the callback
1484                  * to give the caller an opportunity to do so.
1485                  */
1486                 if (ops->callback) {
1487                         if (ops->callback(rec->ip, &entry->data) < 0) {
1488                                 /* caller does not like this func */
1489                                 kfree(entry);
1490                                 continue;
1491                         }
1492                 }
1493
1494                 entry->ops = ops;
1495                 entry->ip = rec->ip;
1496
1497                 key = hash_long(entry->ip, FTRACE_HASH_BITS);
1498                 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
1499
1500         } while_for_each_ftrace_rec();
1501         __enable_ftrace_function_probe();
1502
1503  out_unlock:
1504         mutex_unlock(&ftrace_lock);
1505
1506         return count;
1507 }
1508
1509 enum {
1510         PROBE_TEST_FUNC         = 1,
1511         PROBE_TEST_DATA         = 2
1512 };
1513
1514 static void
1515 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
1516                                   void *data, int flags)
1517 {
1518         struct ftrace_func_probe *entry;
1519         struct hlist_node *n, *tmp;
1520         char str[KSYM_SYMBOL_LEN];
1521         int type = MATCH_FULL;
1522         int i, len = 0;
1523         char *search;
1524
1525         if (glob && (strcmp(glob, "*") || !strlen(glob)))
1526                 glob = NULL;
1527         else {
1528                 int not;
1529
1530                 type = ftrace_setup_glob(glob, strlen(glob), &search, &not);
1531                 len = strlen(search);
1532
1533                 /* we do not support '!' for function probes */
1534                 if (WARN_ON(not))
1535                         return;
1536         }
1537
1538         mutex_lock(&ftrace_lock);
1539         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1540                 struct hlist_head *hhd = &ftrace_func_hash[i];
1541
1542                 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
1543
1544                         /* break up if statements for readability */
1545                         if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
1546                                 continue;
1547
1548                         if ((flags & PROBE_TEST_DATA) && entry->data != data)
1549                                 continue;
1550
1551                         /* do this last, since it is the most expensive */
1552                         if (glob) {
1553                                 kallsyms_lookup(entry->ip, NULL, NULL,
1554                                                 NULL, str);
1555                                 if (!ftrace_match(str, glob, len, type))
1556                                         continue;
1557                         }
1558
1559                         hlist_del(&entry->node);
1560                         call_rcu(&entry->rcu, ftrace_free_entry_rcu);
1561                 }
1562         }
1563         __disable_ftrace_function_probe();
1564         mutex_unlock(&ftrace_lock);
1565 }
1566
1567 void
1568 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
1569                                 void *data)
1570 {
1571         __unregister_ftrace_function_probe(glob, ops, data,
1572                                           PROBE_TEST_FUNC | PROBE_TEST_DATA);
1573 }
1574
1575 void
1576 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
1577 {
1578         __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
1579 }
1580
1581 void unregister_ftrace_function_probe_all(char *glob)
1582 {
1583         __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
1584 }
1585
1586 static LIST_HEAD(ftrace_commands);
1587 static DEFINE_MUTEX(ftrace_cmd_mutex);
1588
1589 int register_ftrace_command(struct ftrace_func_command *cmd)
1590 {
1591         struct ftrace_func_command *p;
1592         int ret = 0;
1593
1594         mutex_lock(&ftrace_cmd_mutex);
1595         list_for_each_entry(p, &ftrace_commands, list) {
1596                 if (strcmp(cmd->name, p->name) == 0) {
1597                         ret = -EBUSY;
1598                         goto out_unlock;
1599                 }
1600         }
1601         list_add(&cmd->list, &ftrace_commands);
1602  out_unlock:
1603         mutex_unlock(&ftrace_cmd_mutex);
1604
1605         return ret;
1606 }
1607
1608 int unregister_ftrace_command(struct ftrace_func_command *cmd)
1609 {
1610         struct ftrace_func_command *p, *n;
1611         int ret = -ENODEV;
1612
1613         mutex_lock(&ftrace_cmd_mutex);
1614         list_for_each_entry_safe(p, n, &ftrace_commands, list) {
1615                 if (strcmp(cmd->name, p->name) == 0) {
1616                         ret = 0;
1617                         list_del_init(&p->list);
1618                         goto out_unlock;
1619                 }
1620         }
1621  out_unlock:
1622         mutex_unlock(&ftrace_cmd_mutex);
1623
1624         return ret;
1625 }
1626
1627 static int ftrace_process_regex(char *buff, int len, int enable)
1628 {
1629         char *func, *command, *next = buff;
1630         struct ftrace_func_command *p;
1631         int ret = -EINVAL;
1632
1633         func = strsep(&next, ":");
1634
1635         if (!next) {
1636                 ftrace_match_records(func, len, enable);
1637                 return 0;
1638         }
1639
1640         /* command found */
1641
1642         command = strsep(&next, ":");
1643
1644         mutex_lock(&ftrace_cmd_mutex);
1645         list_for_each_entry(p, &ftrace_commands, list) {
1646                 if (strcmp(p->name, command) == 0) {
1647                         ret = p->func(func, command, next, enable);
1648                         goto out_unlock;
1649                 }
1650         }
1651  out_unlock:
1652         mutex_unlock(&ftrace_cmd_mutex);
1653
1654         return ret;
1655 }
1656
1657 static ssize_t
1658 ftrace_regex_write(struct file *file, const char __user *ubuf,
1659                    size_t cnt, loff_t *ppos, int enable)
1660 {
1661         struct ftrace_iterator *iter;
1662         char ch;
1663         size_t read = 0;
1664         ssize_t ret;
1665
1666         if (!cnt || cnt < 0)
1667                 return 0;
1668
1669         mutex_lock(&ftrace_regex_lock);
1670
1671         if (file->f_mode & FMODE_READ) {
1672                 struct seq_file *m = file->private_data;
1673                 iter = m->private;
1674         } else
1675                 iter = file->private_data;
1676
1677         if (!*ppos) {
1678                 iter->flags &= ~FTRACE_ITER_CONT;
1679                 iter->buffer_idx = 0;
1680         }
1681
1682         ret = get_user(ch, ubuf++);
1683         if (ret)
1684                 goto out;
1685         read++;
1686         cnt--;
1687
1688         if (!(iter->flags & ~FTRACE_ITER_CONT)) {
1689                 /* skip white space */
1690                 while (cnt && isspace(ch)) {
1691                         ret = get_user(ch, ubuf++);
1692                         if (ret)
1693                                 goto out;
1694                         read++;
1695                         cnt--;
1696                 }
1697
1698                 if (isspace(ch)) {
1699                         file->f_pos += read;
1700                         ret = read;
1701                         goto out;
1702                 }
1703
1704                 iter->buffer_idx = 0;
1705         }
1706
1707         while (cnt && !isspace(ch)) {
1708                 if (iter->buffer_idx < FTRACE_BUFF_MAX)
1709                         iter->buffer[iter->buffer_idx++] = ch;
1710                 else {
1711                         ret = -EINVAL;
1712                         goto out;
1713                 }
1714                 ret = get_user(ch, ubuf++);
1715                 if (ret)
1716                         goto out;
1717                 read++;
1718                 cnt--;
1719         }
1720
1721         if (isspace(ch)) {
1722                 iter->filtered++;
1723                 iter->buffer[iter->buffer_idx] = 0;
1724                 ret = ftrace_process_regex(iter->buffer,
1725                                            iter->buffer_idx, enable);
1726                 if (ret)
1727                         goto out;
1728                 iter->buffer_idx = 0;
1729         } else
1730                 iter->flags |= FTRACE_ITER_CONT;
1731
1732
1733         file->f_pos += read;
1734
1735         ret = read;
1736  out:
1737         mutex_unlock(&ftrace_regex_lock);
1738
1739         return ret;
1740 }
1741
1742 static ssize_t
1743 ftrace_filter_write(struct file *file, const char __user *ubuf,
1744                     size_t cnt, loff_t *ppos)
1745 {
1746         return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
1747 }
1748
1749 static ssize_t
1750 ftrace_notrace_write(struct file *file, const char __user *ubuf,
1751                      size_t cnt, loff_t *ppos)
1752 {
1753         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
1754 }
1755
1756 static void
1757 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
1758 {
1759         if (unlikely(ftrace_disabled))
1760                 return;
1761
1762         mutex_lock(&ftrace_regex_lock);
1763         if (reset)
1764                 ftrace_filter_reset(enable);
1765         if (buf)
1766                 ftrace_match_records(buf, len, enable);
1767         mutex_unlock(&ftrace_regex_lock);
1768 }
1769
1770 /**
1771  * ftrace_set_filter - set a function to filter on in ftrace
1772  * @buf - the string that holds the function filter text.
1773  * @len - the length of the string.
1774  * @reset - non zero to reset all filters before applying this filter.
1775  *
1776  * Filters denote which functions should be enabled when tracing is enabled.
1777  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
1778  */
1779 void ftrace_set_filter(unsigned char *buf, int len, int reset)
1780 {
1781         ftrace_set_regex(buf, len, reset, 1);
1782 }
1783
1784 /**
1785  * ftrace_set_notrace - set a function to not trace in ftrace
1786  * @buf - the string that holds the function notrace text.
1787  * @len - the length of the string.
1788  * @reset - non zero to reset all filters before applying this filter.
1789  *
1790  * Notrace Filters denote which functions should not be enabled when tracing
1791  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
1792  * for tracing.
1793  */
1794 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
1795 {
1796         ftrace_set_regex(buf, len, reset, 0);
1797 }
1798
1799 static int
1800 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
1801 {
1802         struct seq_file *m = (struct seq_file *)file->private_data;
1803         struct ftrace_iterator *iter;
1804
1805         mutex_lock(&ftrace_regex_lock);
1806         if (file->f_mode & FMODE_READ) {
1807                 iter = m->private;
1808
1809                 seq_release(inode, file);
1810         } else
1811                 iter = file->private_data;
1812
1813         if (iter->buffer_idx) {
1814                 iter->filtered++;
1815                 iter->buffer[iter->buffer_idx] = 0;
1816                 ftrace_match_records(iter->buffer, iter->buffer_idx, enable);
1817         }
1818
1819         mutex_lock(&ftrace_lock);
1820         if (ftrace_start_up && ftrace_enabled)
1821                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
1822         mutex_unlock(&ftrace_lock);
1823
1824         kfree(iter);
1825         mutex_unlock(&ftrace_regex_lock);
1826         return 0;
1827 }
1828
1829 static int
1830 ftrace_filter_release(struct inode *inode, struct file *file)
1831 {
1832         return ftrace_regex_release(inode, file, 1);
1833 }
1834
1835 static int
1836 ftrace_notrace_release(struct inode *inode, struct file *file)
1837 {
1838         return ftrace_regex_release(inode, file, 0);
1839 }
1840
1841 static struct file_operations ftrace_avail_fops = {
1842         .open = ftrace_avail_open,
1843         .read = seq_read,
1844         .llseek = seq_lseek,
1845         .release = ftrace_avail_release,
1846 };
1847
1848 static struct file_operations ftrace_failures_fops = {
1849         .open = ftrace_failures_open,
1850         .read = seq_read,
1851         .llseek = seq_lseek,
1852         .release = ftrace_avail_release,
1853 };
1854
1855 static struct file_operations ftrace_filter_fops = {
1856         .open = ftrace_filter_open,
1857         .read = ftrace_regex_read,
1858         .write = ftrace_filter_write,
1859         .llseek = ftrace_regex_lseek,
1860         .release = ftrace_filter_release,
1861 };
1862
1863 static struct file_operations ftrace_notrace_fops = {
1864         .open = ftrace_notrace_open,
1865         .read = ftrace_regex_read,
1866         .write = ftrace_notrace_write,
1867         .llseek = ftrace_regex_lseek,
1868         .release = ftrace_notrace_release,
1869 };
1870
1871 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1872
1873 static DEFINE_MUTEX(graph_lock);
1874
1875 int ftrace_graph_count;
1876 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
1877
1878 static void *
1879 g_next(struct seq_file *m, void *v, loff_t *pos)
1880 {
1881         unsigned long *array = m->private;
1882         int index = *pos;
1883
1884         (*pos)++;
1885
1886         if (index >= ftrace_graph_count)
1887                 return NULL;
1888
1889         return &array[index];
1890 }
1891
1892 static void *g_start(struct seq_file *m, loff_t *pos)
1893 {
1894         void *p = NULL;
1895
1896         mutex_lock(&graph_lock);
1897
1898         /* Nothing, tell g_show to print all functions are enabled */
1899         if (!ftrace_graph_count && !*pos)
1900                 return (void *)1;
1901
1902         p = g_next(m, p, pos);
1903
1904         return p;
1905 }
1906
1907 static void g_stop(struct seq_file *m, void *p)
1908 {
1909         mutex_unlock(&graph_lock);
1910 }
1911
1912 static int g_show(struct seq_file *m, void *v)
1913 {
1914         unsigned long *ptr = v;
1915         char str[KSYM_SYMBOL_LEN];
1916
1917         if (!ptr)
1918                 return 0;
1919
1920         if (ptr == (unsigned long *)1) {
1921                 seq_printf(m, "#### all functions enabled ####\n");
1922                 return 0;
1923         }
1924
1925         kallsyms_lookup(*ptr, NULL, NULL, NULL, str);
1926
1927         seq_printf(m, "%s\n", str);
1928
1929         return 0;
1930 }
1931
1932 static struct seq_operations ftrace_graph_seq_ops = {
1933         .start = g_start,
1934         .next = g_next,
1935         .stop = g_stop,
1936         .show = g_show,
1937 };
1938
1939 static int
1940 ftrace_graph_open(struct inode *inode, struct file *file)
1941 {
1942         int ret = 0;
1943
1944         if (unlikely(ftrace_disabled))
1945                 return -ENODEV;
1946
1947         mutex_lock(&graph_lock);
1948         if ((file->f_mode & FMODE_WRITE) &&
1949             !(file->f_flags & O_APPEND)) {
1950                 ftrace_graph_count = 0;
1951                 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
1952         }
1953
1954         if (file->f_mode & FMODE_READ) {
1955                 ret = seq_open(file, &ftrace_graph_seq_ops);
1956                 if (!ret) {
1957                         struct seq_file *m = file->private_data;
1958                         m->private = ftrace_graph_funcs;
1959                 }
1960         } else
1961                 file->private_data = ftrace_graph_funcs;
1962         mutex_unlock(&graph_lock);
1963
1964         return ret;
1965 }
1966
1967 static ssize_t
1968 ftrace_graph_read(struct file *file, char __user *ubuf,
1969                        size_t cnt, loff_t *ppos)
1970 {
1971         if (file->f_mode & FMODE_READ)
1972                 return seq_read(file, ubuf, cnt, ppos);
1973         else
1974                 return -EPERM;
1975 }
1976
1977 static int
1978 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
1979 {
1980         struct dyn_ftrace *rec;
1981         struct ftrace_page *pg;
1982         int search_len;
1983         int found = 0;
1984         int type, not;
1985         char *search;
1986         bool exists;
1987         int i;
1988
1989         if (ftrace_disabled)
1990                 return -ENODEV;
1991
1992         /* decode regex */
1993         type = ftrace_setup_glob(buffer, strlen(buffer), &search, &not);
1994         if (not)
1995                 return -EINVAL;
1996
1997         search_len = strlen(search);
1998
1999         mutex_lock(&ftrace_lock);
2000         do_for_each_ftrace_rec(pg, rec) {
2001
2002                 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
2003                         break;
2004
2005                 if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
2006                         continue;
2007
2008                 if (ftrace_match_record(rec, search, search_len, type)) {
2009                         /* ensure it is not already in the array */
2010                         exists = false;
2011                         for (i = 0; i < *idx; i++)
2012                                 if (array[i] == rec->ip) {
2013                                         exists = true;
2014                                         break;
2015                                 }
2016                         if (!exists) {
2017                                 array[(*idx)++] = rec->ip;
2018                                 found = 1;
2019                         }
2020                 }
2021         } while_for_each_ftrace_rec();
2022
2023         mutex_unlock(&ftrace_lock);
2024
2025         return found ? 0 : -EINVAL;
2026 }
2027
2028 static ssize_t
2029 ftrace_graph_write(struct file *file, const char __user *ubuf,
2030                    size_t cnt, loff_t *ppos)
2031 {
2032         unsigned char buffer[FTRACE_BUFF_MAX+1];
2033         unsigned long *array;
2034         size_t read = 0;
2035         ssize_t ret;
2036         int index = 0;
2037         char ch;
2038
2039         if (!cnt || cnt < 0)
2040                 return 0;
2041
2042         mutex_lock(&graph_lock);
2043
2044         if (ftrace_graph_count >= FTRACE_GRAPH_MAX_FUNCS) {
2045                 ret = -EBUSY;
2046                 goto out;
2047         }
2048
2049         if (file->f_mode & FMODE_READ) {
2050                 struct seq_file *m = file->private_data;
2051                 array = m->private;
2052         } else
2053                 array = file->private_data;
2054
2055         ret = get_user(ch, ubuf++);
2056         if (ret)
2057                 goto out;
2058         read++;
2059         cnt--;
2060
2061         /* skip white space */
2062         while (cnt && isspace(ch)) {
2063                 ret = get_user(ch, ubuf++);
2064                 if (ret)
2065                         goto out;
2066                 read++;
2067                 cnt--;
2068         }
2069
2070         if (isspace(ch)) {
2071                 *ppos += read;
2072                 ret = read;
2073                 goto out;
2074         }
2075
2076         while (cnt && !isspace(ch)) {
2077                 if (index < FTRACE_BUFF_MAX)
2078                         buffer[index++] = ch;
2079                 else {
2080                         ret = -EINVAL;
2081                         goto out;
2082                 }
2083                 ret = get_user(ch, ubuf++);
2084                 if (ret)
2085                         goto out;
2086                 read++;
2087                 cnt--;
2088         }
2089         buffer[index] = 0;
2090
2091         /* we allow only one expression at a time */
2092         ret = ftrace_set_func(array, &ftrace_graph_count, buffer);
2093         if (ret)
2094                 goto out;
2095
2096         file->f_pos += read;
2097
2098         ret = read;
2099  out:
2100         mutex_unlock(&graph_lock);
2101
2102         return ret;
2103 }
2104
2105 static const struct file_operations ftrace_graph_fops = {
2106         .open = ftrace_graph_open,
2107         .read = ftrace_graph_read,
2108         .write = ftrace_graph_write,
2109 };
2110 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2111
2112 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
2113 {
2114         struct dentry *entry;
2115
2116         entry = debugfs_create_file("available_filter_functions", 0444,
2117                                     d_tracer, NULL, &ftrace_avail_fops);
2118         if (!entry)
2119                 pr_warning("Could not create debugfs "
2120                            "'available_filter_functions' entry\n");
2121
2122         entry = debugfs_create_file("failures", 0444,
2123                                     d_tracer, NULL, &ftrace_failures_fops);
2124         if (!entry)
2125                 pr_warning("Could not create debugfs 'failures' entry\n");
2126
2127         entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer,
2128                                     NULL, &ftrace_filter_fops);
2129         if (!entry)
2130                 pr_warning("Could not create debugfs "
2131                            "'set_ftrace_filter' entry\n");
2132
2133         entry = debugfs_create_file("set_ftrace_notrace", 0644, d_tracer,
2134                                     NULL, &ftrace_notrace_fops);
2135         if (!entry)
2136                 pr_warning("Could not create debugfs "
2137                            "'set_ftrace_notrace' entry\n");
2138
2139 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2140         entry = debugfs_create_file("set_graph_function", 0444, d_tracer,
2141                                     NULL,
2142                                     &ftrace_graph_fops);
2143         if (!entry)
2144                 pr_warning("Could not create debugfs "
2145                            "'set_graph_function' entry\n");
2146 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2147
2148         return 0;
2149 }
2150
2151 static int ftrace_convert_nops(struct module *mod,
2152                                unsigned long *start,
2153                                unsigned long *end)
2154 {
2155         unsigned long *p;
2156         unsigned long addr;
2157         unsigned long flags;
2158
2159         mutex_lock(&ftrace_lock);
2160         p = start;
2161         while (p < end) {
2162                 addr = ftrace_call_adjust(*p++);
2163                 /*
2164                  * Some architecture linkers will pad between
2165                  * the different mcount_loc sections of different
2166                  * object files to satisfy alignments.
2167                  * Skip any NULL pointers.
2168                  */
2169                 if (!addr)
2170                         continue;
2171                 ftrace_record_ip(addr);
2172         }
2173
2174         /* disable interrupts to prevent kstop machine */
2175         local_irq_save(flags);
2176         ftrace_update_code(mod);
2177         local_irq_restore(flags);
2178         mutex_unlock(&ftrace_lock);
2179
2180         return 0;
2181 }
2182
2183 void ftrace_init_module(struct module *mod,
2184                         unsigned long *start, unsigned long *end)
2185 {
2186         if (ftrace_disabled || start == end)
2187                 return;
2188         ftrace_convert_nops(mod, start, end);
2189 }
2190
2191 extern unsigned long __start_mcount_loc[];
2192 extern unsigned long __stop_mcount_loc[];
2193
2194 void __init ftrace_init(void)
2195 {
2196         unsigned long count, addr, flags;
2197         int ret;
2198
2199         /* Keep the ftrace pointer to the stub */
2200         addr = (unsigned long)ftrace_stub;
2201
2202         local_irq_save(flags);
2203         ftrace_dyn_arch_init(&addr);
2204         local_irq_restore(flags);
2205
2206         /* ftrace_dyn_arch_init places the return code in addr */
2207         if (addr)
2208                 goto failed;
2209
2210         count = __stop_mcount_loc - __start_mcount_loc;
2211
2212         ret = ftrace_dyn_table_alloc(count);
2213         if (ret)
2214                 goto failed;
2215
2216         last_ftrace_enabled = ftrace_enabled = 1;
2217
2218         ret = ftrace_convert_nops(NULL,
2219                                   __start_mcount_loc,
2220                                   __stop_mcount_loc);
2221
2222         return;
2223  failed:
2224         ftrace_disabled = 1;
2225 }
2226
2227 #else
2228
2229 static int __init ftrace_nodyn_init(void)
2230 {
2231         ftrace_enabled = 1;
2232         return 0;
2233 }
2234 device_initcall(ftrace_nodyn_init);
2235
2236 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
2237 static inline void ftrace_startup_enable(int command) { }
2238 /* Keep as macros so we do not need to define the commands */
2239 # define ftrace_startup(command)        do { } while (0)
2240 # define ftrace_shutdown(command)       do { } while (0)
2241 # define ftrace_startup_sysctl()        do { } while (0)
2242 # define ftrace_shutdown_sysctl()       do { } while (0)
2243 #endif /* CONFIG_DYNAMIC_FTRACE */
2244
2245 static ssize_t
2246 ftrace_pid_read(struct file *file, char __user *ubuf,
2247                        size_t cnt, loff_t *ppos)
2248 {
2249         char buf[64];
2250         int r;
2251
2252         if (ftrace_pid_trace == ftrace_swapper_pid)
2253                 r = sprintf(buf, "swapper tasks\n");
2254         else if (ftrace_pid_trace)
2255                 r = sprintf(buf, "%u\n", pid_nr(ftrace_pid_trace));
2256         else
2257                 r = sprintf(buf, "no pid\n");
2258
2259         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2260 }
2261
2262 static void clear_ftrace_swapper(void)
2263 {
2264         struct task_struct *p;
2265         int cpu;
2266
2267         get_online_cpus();
2268         for_each_online_cpu(cpu) {
2269                 p = idle_task(cpu);
2270                 clear_tsk_trace_trace(p);
2271         }
2272         put_online_cpus();
2273 }
2274
2275 static void set_ftrace_swapper(void)
2276 {
2277         struct task_struct *p;
2278         int cpu;
2279
2280         get_online_cpus();
2281         for_each_online_cpu(cpu) {
2282                 p = idle_task(cpu);
2283                 set_tsk_trace_trace(p);
2284         }
2285         put_online_cpus();
2286 }
2287
2288 static void clear_ftrace_pid(struct pid *pid)
2289 {
2290         struct task_struct *p;
2291
2292         rcu_read_lock();
2293         do_each_pid_task(pid, PIDTYPE_PID, p) {
2294                 clear_tsk_trace_trace(p);
2295         } while_each_pid_task(pid, PIDTYPE_PID, p);
2296         rcu_read_unlock();
2297
2298         put_pid(pid);
2299 }
2300
2301 static void set_ftrace_pid(struct pid *pid)
2302 {
2303         struct task_struct *p;
2304
2305         rcu_read_lock();
2306         do_each_pid_task(pid, PIDTYPE_PID, p) {
2307                 set_tsk_trace_trace(p);
2308         } while_each_pid_task(pid, PIDTYPE_PID, p);
2309         rcu_read_unlock();
2310 }
2311
2312 static void clear_ftrace_pid_task(struct pid **pid)
2313 {
2314         if (*pid == ftrace_swapper_pid)
2315                 clear_ftrace_swapper();
2316         else
2317                 clear_ftrace_pid(*pid);
2318
2319         *pid = NULL;
2320 }
2321
2322 static void set_ftrace_pid_task(struct pid *pid)
2323 {
2324         if (pid == ftrace_swapper_pid)
2325                 set_ftrace_swapper();
2326         else
2327                 set_ftrace_pid(pid);
2328 }
2329
2330 static ssize_t
2331 ftrace_pid_write(struct file *filp, const char __user *ubuf,
2332                    size_t cnt, loff_t *ppos)
2333 {
2334         struct pid *pid;
2335         char buf[64];
2336         long val;
2337         int ret;
2338
2339         if (cnt >= sizeof(buf))
2340                 return -EINVAL;
2341
2342         if (copy_from_user(&buf, ubuf, cnt))
2343                 return -EFAULT;
2344
2345         buf[cnt] = 0;
2346
2347         ret = strict_strtol(buf, 10, &val);
2348         if (ret < 0)
2349                 return ret;
2350
2351         mutex_lock(&ftrace_lock);
2352         if (val < 0) {
2353                 /* disable pid tracing */
2354                 if (!ftrace_pid_trace)
2355                         goto out;
2356
2357                 clear_ftrace_pid_task(&ftrace_pid_trace);
2358
2359         } else {
2360                 /* swapper task is special */
2361                 if (!val) {
2362                         pid = ftrace_swapper_pid;
2363                         if (pid == ftrace_pid_trace)
2364                                 goto out;
2365                 } else {
2366                         pid = find_get_pid(val);
2367
2368                         if (pid == ftrace_pid_trace) {
2369                                 put_pid(pid);
2370                                 goto out;
2371                         }
2372                 }
2373
2374                 if (ftrace_pid_trace)
2375                         clear_ftrace_pid_task(&ftrace_pid_trace);
2376
2377                 if (!pid)
2378                         goto out;
2379
2380                 ftrace_pid_trace = pid;
2381
2382                 set_ftrace_pid_task(ftrace_pid_trace);
2383         }
2384
2385         /* update the function call */
2386         ftrace_update_pid_func();
2387         ftrace_startup_enable(0);
2388
2389  out:
2390         mutex_unlock(&ftrace_lock);
2391
2392         return cnt;
2393 }
2394
2395 static struct file_operations ftrace_pid_fops = {
2396         .read = ftrace_pid_read,
2397         .write = ftrace_pid_write,
2398 };
2399
2400 static __init int ftrace_init_debugfs(void)
2401 {
2402         struct dentry *d_tracer;
2403         struct dentry *entry;
2404
2405         d_tracer = tracing_init_dentry();
2406         if (!d_tracer)
2407                 return 0;
2408
2409         ftrace_init_dyn_debugfs(d_tracer);
2410
2411         entry = debugfs_create_file("set_ftrace_pid", 0644, d_tracer,
2412                                     NULL, &ftrace_pid_fops);
2413         if (!entry)
2414                 pr_warning("Could not create debugfs "
2415                            "'set_ftrace_pid' entry\n");
2416         return 0;
2417 }
2418 fs_initcall(ftrace_init_debugfs);
2419
2420 /**
2421  * ftrace_kill - kill ftrace
2422  *
2423  * This function should be used by panic code. It stops ftrace
2424  * but in a not so nice way. If you need to simply kill ftrace
2425  * from a non-atomic section, use ftrace_kill.
2426  */
2427 void ftrace_kill(void)
2428 {
2429         ftrace_disabled = 1;
2430         ftrace_enabled = 0;
2431         clear_ftrace_function();
2432 }
2433
2434 /**
2435  * register_ftrace_function - register a function for profiling
2436  * @ops - ops structure that holds the function for profiling.
2437  *
2438  * Register a function to be called by all functions in the
2439  * kernel.
2440  *
2441  * Note: @ops->func and all the functions it calls must be labeled
2442  *       with "notrace", otherwise it will go into a
2443  *       recursive loop.
2444  */
2445 int register_ftrace_function(struct ftrace_ops *ops)
2446 {
2447         int ret;
2448
2449         if (unlikely(ftrace_disabled))
2450                 return -1;
2451
2452         mutex_lock(&ftrace_lock);
2453
2454         ret = __register_ftrace_function(ops);
2455         ftrace_startup(0);
2456
2457         mutex_unlock(&ftrace_lock);
2458         return ret;
2459 }
2460
2461 /**
2462  * unregister_ftrace_function - unregister a function for profiling.
2463  * @ops - ops structure that holds the function to unregister
2464  *
2465  * Unregister a function that was added to be called by ftrace profiling.
2466  */
2467 int unregister_ftrace_function(struct ftrace_ops *ops)
2468 {
2469         int ret;
2470
2471         mutex_lock(&ftrace_lock);
2472         ret = __unregister_ftrace_function(ops);
2473         ftrace_shutdown(0);
2474         mutex_unlock(&ftrace_lock);
2475
2476         return ret;
2477 }
2478
2479 int
2480 ftrace_enable_sysctl(struct ctl_table *table, int write,
2481                      struct file *file, void __user *buffer, size_t *lenp,
2482                      loff_t *ppos)
2483 {
2484         int ret;
2485
2486         if (unlikely(ftrace_disabled))
2487                 return -ENODEV;
2488
2489         mutex_lock(&ftrace_lock);
2490
2491         ret  = proc_dointvec(table, write, file, buffer, lenp, ppos);
2492
2493         if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
2494                 goto out;
2495
2496         last_ftrace_enabled = ftrace_enabled;
2497
2498         if (ftrace_enabled) {
2499
2500                 ftrace_startup_sysctl();
2501
2502                 /* we are starting ftrace again */
2503                 if (ftrace_list != &ftrace_list_end) {
2504                         if (ftrace_list->next == &ftrace_list_end)
2505                                 ftrace_trace_function = ftrace_list->func;
2506                         else
2507                                 ftrace_trace_function = ftrace_list_func;
2508                 }
2509
2510         } else {
2511                 /* stopping ftrace calls (just send to ftrace_stub) */
2512                 ftrace_trace_function = ftrace_stub;
2513
2514                 ftrace_shutdown_sysctl();
2515         }
2516
2517  out:
2518         mutex_unlock(&ftrace_lock);
2519         return ret;
2520 }
2521
2522 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2523
2524 static atomic_t ftrace_graph_active;
2525 static struct notifier_block ftrace_suspend_notifier;
2526
2527 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
2528 {
2529         return 0;
2530 }
2531
2532 /* The callbacks that hook a function */
2533 trace_func_graph_ret_t ftrace_graph_return =
2534                         (trace_func_graph_ret_t)ftrace_stub;
2535 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
2536
2537 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
2538 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
2539 {
2540         int i;
2541         int ret = 0;
2542         unsigned long flags;
2543         int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
2544         struct task_struct *g, *t;
2545
2546         for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
2547                 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
2548                                         * sizeof(struct ftrace_ret_stack),
2549                                         GFP_KERNEL);
2550                 if (!ret_stack_list[i]) {
2551                         start = 0;
2552                         end = i;
2553                         ret = -ENOMEM;
2554                         goto free;
2555                 }
2556         }
2557
2558         read_lock_irqsave(&tasklist_lock, flags);
2559         do_each_thread(g, t) {
2560                 if (start == end) {
2561                         ret = -EAGAIN;
2562                         goto unlock;
2563                 }
2564
2565                 if (t->ret_stack == NULL) {
2566                         t->curr_ret_stack = -1;
2567                         /* Make sure IRQs see the -1 first: */
2568                         barrier();
2569                         t->ret_stack = ret_stack_list[start++];
2570                         atomic_set(&t->tracing_graph_pause, 0);
2571                         atomic_set(&t->trace_overrun, 0);
2572                 }
2573         } while_each_thread(g, t);
2574
2575 unlock:
2576         read_unlock_irqrestore(&tasklist_lock, flags);
2577 free:
2578         for (i = start; i < end; i++)
2579                 kfree(ret_stack_list[i]);
2580         return ret;
2581 }
2582
2583 /* Allocate a return stack for each task */
2584 static int start_graph_tracing(void)
2585 {
2586         struct ftrace_ret_stack **ret_stack_list;
2587         int ret, cpu;
2588
2589         ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
2590                                 sizeof(struct ftrace_ret_stack *),
2591                                 GFP_KERNEL);
2592
2593         if (!ret_stack_list)
2594                 return -ENOMEM;
2595
2596         /* The cpu_boot init_task->ret_stack will never be freed */
2597         for_each_online_cpu(cpu)
2598                 ftrace_graph_init_task(idle_task(cpu));
2599
2600         do {
2601                 ret = alloc_retstack_tasklist(ret_stack_list);
2602         } while (ret == -EAGAIN);
2603
2604         kfree(ret_stack_list);
2605         return ret;
2606 }
2607
2608 /*
2609  * Hibernation protection.
2610  * The state of the current task is too much unstable during
2611  * suspend/restore to disk. We want to protect against that.
2612  */
2613 static int
2614 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
2615                                                         void *unused)
2616 {
2617         switch (state) {
2618         case PM_HIBERNATION_PREPARE:
2619                 pause_graph_tracing();
2620                 break;
2621
2622         case PM_POST_HIBERNATION:
2623                 unpause_graph_tracing();
2624                 break;
2625         }
2626         return NOTIFY_DONE;
2627 }
2628
2629 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
2630                         trace_func_graph_ent_t entryfunc)
2631 {
2632         int ret = 0;
2633
2634         mutex_lock(&ftrace_lock);
2635
2636         ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
2637         register_pm_notifier(&ftrace_suspend_notifier);
2638
2639         atomic_inc(&ftrace_graph_active);
2640         ret = start_graph_tracing();
2641         if (ret) {
2642                 atomic_dec(&ftrace_graph_active);
2643                 goto out;
2644         }
2645
2646         ftrace_graph_return = retfunc;
2647         ftrace_graph_entry = entryfunc;
2648
2649         ftrace_startup(FTRACE_START_FUNC_RET);
2650
2651 out:
2652         mutex_unlock(&ftrace_lock);
2653         return ret;
2654 }
2655
2656 void unregister_ftrace_graph(void)
2657 {
2658         mutex_lock(&ftrace_lock);
2659
2660         atomic_dec(&ftrace_graph_active);
2661         ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
2662         ftrace_graph_entry = ftrace_graph_entry_stub;
2663         ftrace_shutdown(FTRACE_STOP_FUNC_RET);
2664         unregister_pm_notifier(&ftrace_suspend_notifier);
2665
2666         mutex_unlock(&ftrace_lock);
2667 }
2668
2669 /* Allocate a return stack for newly created task */
2670 void ftrace_graph_init_task(struct task_struct *t)
2671 {
2672         if (atomic_read(&ftrace_graph_active)) {
2673                 t->ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
2674                                 * sizeof(struct ftrace_ret_stack),
2675                                 GFP_KERNEL);
2676                 if (!t->ret_stack)
2677                         return;
2678                 t->curr_ret_stack = -1;
2679                 atomic_set(&t->tracing_graph_pause, 0);
2680                 atomic_set(&t->trace_overrun, 0);
2681         } else
2682                 t->ret_stack = NULL;
2683 }
2684
2685 void ftrace_graph_exit_task(struct task_struct *t)
2686 {
2687         struct ftrace_ret_stack *ret_stack = t->ret_stack;
2688
2689         t->ret_stack = NULL;
2690         /* NULL must become visible to IRQs before we free it: */
2691         barrier();
2692
2693         kfree(ret_stack);
2694 }
2695
2696 void ftrace_graph_stop(void)
2697 {
2698         ftrace_stop();
2699 }
2700 #endif
2701