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/module.h>
  26 #include <linux/ftrace.h>
  27 #include <linux/sysctl.h>
  28 #include <linux/slab.h>
  29 #include <linux/ctype.h>
  30 #include <linux/list.h>
  31 #include <linux/hash.h>
  32 #include <linux/rcupdate.h>
  33
  34 #include <trace/events/sched.h>
  35
  36 #include <asm/setup.h>
  37
  38 #include "trace_output.h"
  39 #include "trace_stat.h"
  40
  41 #define FTRACE_WARN_ON(cond)                    \
  42         ({                                      \
  43                 int ___r = cond;                \
  44                 if (WARN_ON(___r))              \
  45                         ftrace_kill();          \
  46                 ___r;                           \
  47         })
  48
  49 #define FTRACE_WARN_ON_ONCE(cond)               \
  50         ({                                      \
  51                 int ___r = cond;                \
  52                 if (WARN_ON_ONCE(___r))         \
  53                         ftrace_kill();          \
  54                 ___r;                           \
  55         })
  56
  57 /* hash bits for specific function selection */
  58 #define FTRACE_HASH_BITS 7
  59 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
  60 #define FTRACE_HASH_DEFAULT_BITS 10
  61 #define FTRACE_HASH_MAX_BITS 12
  62
  63 /* ftrace_enabled is a method to turn ftrace on or off */
  64 int ftrace_enabled __read_mostly;
  65 static int last_ftrace_enabled;
  66
  67 /* Quick disabling of function tracer. */
  68 int function_trace_stop;
  69
  70 /* List for set_ftrace_pid's pids. */
  71 LIST_HEAD(ftrace_pids);
  72 struct ftrace_pid {
  73         struct list_head list;
  74         struct pid *pid;
  75 };
  76
  77 /*
  78  * ftrace_disabled is set when an anomaly is discovered.
  79  * ftrace_disabled is much stronger than ftrace_enabled.
  80  */
  81 static int ftrace_disabled __read_mostly;
  82
  83 static DEFINE_MUTEX(ftrace_lock);
  84
  85 static struct ftrace_ops ftrace_list_end __read_mostly = {
  86         .func           = ftrace_stub,
  87 };
  88
  89 static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
  90 static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
  91 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
  92 static ftrace_func_t __ftrace_trace_function_delay __read_mostly = ftrace_stub;
  93 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
  94 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
  95 static struct ftrace_ops global_ops;
  96
  97 static void
  98 ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip);
  99
 100 /*
 101  * Traverse the ftrace_global_list, invoking all entries.  The reason that we
 102  * can use rcu_dereference_raw() is that elements removed from this list
 103  * are simply leaked, so there is no need to interact with a grace-period
 104  * mechanism.  The rcu_dereference_raw() calls are needed to handle
 105  * concurrent insertions into the ftrace_global_list.
 106  *
 107  * Silly Alpha and silly pointer-speculation compiler optimizations!
 108  */
 109 static void ftrace_global_list_func(unsigned long ip,
 110                                     unsigned long parent_ip)
 111 {
 112         struct ftrace_ops *op;
 113
 114         if (unlikely(trace_recursion_test(TRACE_GLOBAL_BIT)))
 115                 return;
 116
 117         trace_recursion_set(TRACE_GLOBAL_BIT);
 118         op = rcu_dereference_raw(ftrace_global_list); /*see above*/
 119         while (op != &ftrace_list_end) {
 120                 op->func(ip, parent_ip);
 121                 op = rcu_dereference_raw(op->next); /*see above*/
 122         };
 123         trace_recursion_clear(TRACE_GLOBAL_BIT);
 124 }
 125
 126 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
 127 {
 128         if (!test_tsk_trace_trace(current))
 129                 return;
 130
 131         ftrace_pid_function(ip, parent_ip);
 132 }
 133
 134 static void set_ftrace_pid_function(ftrace_func_t func)
 135 {
 136         /* do not set ftrace_pid_function to itself! */
 137         if (func != ftrace_pid_func)
 138                 ftrace_pid_function = func;
 139 }
 140
 141 /**
 142  * clear_ftrace_function - reset the ftrace function
 143  *
 144  * This NULLs the ftrace function and in essence stops
 145  * tracing.  There may be lag
 146  */
 147 void clear_ftrace_function(void)
 148 {
 149         ftrace_trace_function = ftrace_stub;
 150         __ftrace_trace_function = ftrace_stub;
 151         __ftrace_trace_function_delay = ftrace_stub;
 152         ftrace_pid_function = ftrace_stub;
 153 }
 154
 155 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 156 /*
 157  * For those archs that do not test ftrace_trace_stop in their
 158  * mcount call site, we need to do it from C.
 159  */
 160 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
 161 {
 162         if (function_trace_stop)
 163                 return;
 164
 165         __ftrace_trace_function(ip, parent_ip);
 166 }
 167 #endif
 168
 169 static void update_global_ops(void)
 170 {
 171         ftrace_func_t func;
 172
 173         /*
 174          * If there's only one function registered, then call that
 175          * function directly. Otherwise, we need to iterate over the
 176          * registered callers.
 177          */
 178         if (ftrace_global_list == &ftrace_list_end ||
 179             ftrace_global_list->next == &ftrace_list_end)
 180                 func = ftrace_global_list->func;
 181         else
 182                 func = ftrace_global_list_func;
 183
 184         /* If we filter on pids, update to use the pid function */
 185         if (!list_empty(&ftrace_pids)) {
 186                 set_ftrace_pid_function(func);
 187                 func = ftrace_pid_func;
 188         }
 189
 190         global_ops.func = func;
 191 }
 192
 193 static void update_ftrace_function(void)
 194 {
 195         ftrace_func_t func;
 196
 197         update_global_ops();
 198
 199         /*
 200          * If we are at the end of the list and this ops is
 201          * not dynamic, then have the mcount trampoline call
 202          * the function directly
 203          */
 204         if (ftrace_ops_list == &ftrace_list_end ||
 205             (ftrace_ops_list->next == &ftrace_list_end &&
 206              !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC)))
 207                 func = ftrace_ops_list->func;
 208         else
 209                 func = ftrace_ops_list_func;
 210
 211 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 212         ftrace_trace_function = func;
 213 #else
 214 #ifdef CONFIG_DYNAMIC_FTRACE
 215         /* do not update till all functions have been modified */
 216         __ftrace_trace_function_delay = func;
 217 #else
 218         __ftrace_trace_function = func;
 219 #endif
 220         ftrace_trace_function = ftrace_test_stop_func;
 221 #endif
 222 }
 223
 224 static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
 225 {
 226         ops->next = *list;
 227         /*
 228          * We are entering ops into the list but another
 229          * CPU might be walking that list. We need to make sure
 230          * the ops->next pointer is valid before another CPU sees
 231          * the ops pointer included into the list.
 232          */
 233         rcu_assign_pointer(*list, ops);
 234 }
 235
 236 static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
 237 {
 238         struct ftrace_ops **p;
 239
 240         /*
 241          * If we are removing the last function, then simply point
 242          * to the ftrace_stub.
 243          */
 244         if (*list == ops && ops->next == &ftrace_list_end) {
 245                 *list = &ftrace_list_end;
 246                 return 0;
 247         }
 248
 249         for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
 250                 if (*p == ops)
 251                         break;
 252
 253         if (*p != ops)
 254                 return -1;
 255
 256         *p = (*p)->next;
 257         return 0;
 258 }
 259
 260 static int __register_ftrace_function(struct ftrace_ops *ops)
 261 {
 262         if (ftrace_disabled)
 263                 return -ENODEV;
 264
 265         if (FTRACE_WARN_ON(ops == &global_ops))
 266                 return -EINVAL;
 267
 268         if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
 269                 return -EBUSY;
 270
 271         if (!core_kernel_data((unsigned long)ops))
 272                 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
 273
 274         if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
 275                 int first = ftrace_global_list == &ftrace_list_end;
 276                 add_ftrace_ops(&ftrace_global_list, ops);
 277                 ops->flags |= FTRACE_OPS_FL_ENABLED;
 278                 if (first)
 279                         add_ftrace_ops(&ftrace_ops_list, &global_ops);
 280         } else
 281                 add_ftrace_ops(&ftrace_ops_list, ops);
 282
 283         if (ftrace_enabled)
 284                 update_ftrace_function();
 285
 286         return 0;
 287 }
 288
 289 static int __unregister_ftrace_function(struct ftrace_ops *ops)
 290 {
 291         int ret;
 292
 293         if (ftrace_disabled)
 294                 return -ENODEV;
 295
 296         if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
 297                 return -EBUSY;
 298
 299         if (FTRACE_WARN_ON(ops == &global_ops))
 300                 return -EINVAL;
 301
 302         if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
 303                 ret = remove_ftrace_ops(&ftrace_global_list, ops);
 304                 if (!ret && ftrace_global_list == &ftrace_list_end)
 305                         ret = remove_ftrace_ops(&ftrace_ops_list, &global_ops);
 306                 if (!ret)
 307                         ops->flags &= ~FTRACE_OPS_FL_ENABLED;
 308         } else
 309                 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
 310
 311         if (ret < 0)
 312                 return ret;
 313
 314         if (ftrace_enabled)
 315                 update_ftrace_function();
 316
 317         /*
 318          * Dynamic ops may be freed, we must make sure that all
 319          * callers are done before leaving this function.
 320          */
 321         if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
 322                 synchronize_sched();
 323
 324         return 0;
 325 }
 326
 327 static void ftrace_update_pid_func(void)
 328 {
 329         /* Only do something if we are tracing something */
 330         if (ftrace_trace_function == ftrace_stub)
 331                 return;
 332
 333         update_ftrace_function();
 334 }
 335
 336 #ifdef CONFIG_FUNCTION_PROFILER
 337 struct ftrace_profile {
 338         struct hlist_node               node;
 339         unsigned long                   ip;
 340         unsigned long                   counter;
 341 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 342         unsigned long long              time;
 343         unsigned long long              time_squared;
 344 #endif
 345 };
 346
 347 struct ftrace_profile_page {
 348         struct ftrace_profile_page      *next;
 349         unsigned long                   index;
 350         struct ftrace_profile           records[];
 351 };
 352
 353 struct ftrace_profile_stat {
 354         atomic_t                        disabled;
 355         struct hlist_head               *hash;
 356         struct ftrace_profile_page      *pages;
 357         struct ftrace_profile_page      *start;
 358         struct tracer_stat              stat;
 359 };
 360
 361 #define PROFILE_RECORDS_SIZE                                            \
 362         (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
 363
 364 #define PROFILES_PER_PAGE                                       \
 365         (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
 366
 367 static int ftrace_profile_bits __read_mostly;
 368 static int ftrace_profile_enabled __read_mostly;
 369
 370 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
 371 static DEFINE_MUTEX(ftrace_profile_lock);
 372
 373 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
 374
 375 #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
 376
 377 static void *
 378 function_stat_next(void *v, int idx)
 379 {
 380         struct ftrace_profile *rec = v;
 381         struct ftrace_profile_page *pg;
 382
 383         pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
 384
 385  again:
 386         if (idx != 0)
 387                 rec++;
 388
 389         if ((void *)rec >= (void *)&pg->records[pg->index]) {
 390                 pg = pg->next;
 391                 if (!pg)
 392                         return NULL;
 393                 rec = &pg->records[0];
 394                 if (!rec->counter)
 395                         goto again;
 396         }
 397
 398         return rec;
 399 }
 400
 401 static void *function_stat_start(struct tracer_stat *trace)
 402 {
 403         struct ftrace_profile_stat *stat =
 404                 container_of(trace, struct ftrace_profile_stat, stat);
 405
 406         if (!stat || !stat->start)
 407                 return NULL;
 408
 409         return function_stat_next(&stat->start->records[0], 0);
 410 }
 411
 412 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 413 /* function graph compares on total time */
 414 static int function_stat_cmp(void *p1, void *p2)
 415 {
 416         struct ftrace_profile *a = p1;
 417         struct ftrace_profile *b = p2;
 418
 419         if (a->time < b->time)
 420                 return -1;
 421         if (a->time > b->time)
 422                 return 1;
 423         else
 424                 return 0;
 425 }
 426 #else
 427 /* not function graph compares against hits */
 428 static int function_stat_cmp(void *p1, void *p2)
 429 {
 430         struct ftrace_profile *a = p1;
 431         struct ftrace_profile *b = p2;
 432
 433         if (a->counter < b->counter)
 434                 return -1;
 435         if (a->counter > b->counter)
 436                 return 1;
 437         else
 438                 return 0;
 439 }
 440 #endif
 441
 442 static int function_stat_headers(struct seq_file *m)
 443 {
 444 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 445         seq_printf(m, "  Function                               "
 446                    "Hit    Time            Avg             s^2\n"
 447                       "  --------                               "
 448                    "---    ----            ---             ---\n");
 449 #else
 450         seq_printf(m, "  Function                               Hit\n"
 451                       "  --------                               ---\n");
 452 #endif
 453         return 0;
 454 }
 455
 456 static int function_stat_show(struct seq_file *m, void *v)
 457 {
 458         struct ftrace_profile *rec = v;
 459         char str[KSYM_SYMBOL_LEN];
 460         int ret = 0;
 461 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 462         static struct trace_seq s;
 463         unsigned long long avg;
 464         unsigned long long stddev;
 465 #endif
 466         mutex_lock(&ftrace_profile_lock);
 467
 468         /* we raced with function_profile_reset() */
 469         if (unlikely(rec->counter == 0)) {
 470                 ret = -EBUSY;
 471                 goto out;
 472         }
 473
 474         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 475         seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);
 476
 477 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 478         seq_printf(m, "    ");
 479         avg = rec->time;
 480         do_div(avg, rec->counter);
 481
 482         /* Sample standard deviation (s^2) */
 483         if (rec->counter <= 1)
 484                 stddev = 0;
 485         else {
 486                 stddev = rec->time_squared - rec->counter * avg * avg;
 487                 /*
 488                  * Divide only 1000 for ns^2 -> us^2 conversion.
 489                  * trace_print_graph_duration will divide 1000 again.
 490                  */
 491                 do_div(stddev, (rec->counter - 1) * 1000);
 492         }
 493
 494         trace_seq_init(&s);
 495         trace_print_graph_duration(rec->time, &s);
 496         trace_seq_puts(&s, "    ");
 497         trace_print_graph_duration(avg, &s);
 498         trace_seq_puts(&s, "    ");
 499         trace_print_graph_duration(stddev, &s);
 500         trace_print_seq(m, &s);
 501 #endif
 502         seq_putc(m, '\n');
 503 out:
 504         mutex_unlock(&ftrace_profile_lock);
 505
 506         return ret;
 507 }
 508
 509 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
 510 {
 511         struct ftrace_profile_page *pg;
 512
 513         pg = stat->pages = stat->start;
 514
 515         while (pg) {
 516                 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
 517                 pg->index = 0;
 518                 pg = pg->next;
 519         }
 520
 521         memset(stat->hash, 0,
 522                FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
 523 }
 524
 525 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
 526 {
 527         struct ftrace_profile_page *pg;
 528         int functions;
 529         int pages;
 530         int i;
 531
 532         /* If we already allocated, do nothing */
 533         if (stat->pages)
 534                 return 0;
 535
 536         stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
 537         if (!stat->pages)
 538                 return -ENOMEM;
 539
 540 #ifdef CONFIG_DYNAMIC_FTRACE
 541         functions = ftrace_update_tot_cnt;
 542 #else
 543         /*
 544          * We do not know the number of functions that exist because
 545          * dynamic tracing is what counts them. With past experience
 546          * we have around 20K functions. That should be more than enough.
 547          * It is highly unlikely we will execute every function in
 548          * the kernel.
 549          */
 550         functions = 20000;
 551 #endif
 552
 553         pg = stat->start = stat->pages;
 554
 555         pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
 556
 557         for (i = 0; i < pages; i++) {
 558                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
 559                 if (!pg->next)
 560                         goto out_free;
 561                 pg = pg->next;
 562         }
 563
 564         return 0;
 565
 566  out_free:
 567         pg = stat->start;
 568         while (pg) {
 569                 unsigned long tmp = (unsigned long)pg;
 570
 571                 pg = pg->next;
 572                 free_page(tmp);
 573         }
 574
 575         stat->pages = NULL;
 576         stat->start = NULL;
 577
 578         return -ENOMEM;
 579 }
 580
 581 static int ftrace_profile_init_cpu(int cpu)
 582 {
 583         struct ftrace_profile_stat *stat;
 584         int size;
 585
 586         stat = &per_cpu(ftrace_profile_stats, cpu);
 587
 588         if (stat->hash) {
 589                 /* If the profile is already created, simply reset it */
 590                 ftrace_profile_reset(stat);
 591                 return 0;
 592         }
 593
 594         /*
 595          * We are profiling all functions, but usually only a few thousand
 596          * functions are hit. We'll make a hash of 1024 items.
 597          */
 598         size = FTRACE_PROFILE_HASH_SIZE;
 599
 600         stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
 601
 602         if (!stat->hash)
 603                 return -ENOMEM;
 604
 605         if (!ftrace_profile_bits) {
 606                 size--;
 607
 608                 for (; size; size >>= 1)
 609                         ftrace_profile_bits++;
 610         }
 611
 612         /* Preallocate the function profiling pages */
 613         if (ftrace_profile_pages_init(stat) < 0) {
 614                 kfree(stat->hash);
 615                 stat->hash = NULL;
 616                 return -ENOMEM;
 617         }
 618
 619         return 0;
 620 }
 621
 622 static int ftrace_profile_init(void)
 623 {
 624         int cpu;
 625         int ret = 0;
 626
 627         for_each_online_cpu(cpu) {
 628                 ret = ftrace_profile_init_cpu(cpu);
 629                 if (ret)
 630                         break;
 631         }
 632
 633         return ret;
 634 }
 635
 636 /* interrupts must be disabled */
 637 static struct ftrace_profile *
 638 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
 639 {
 640         struct ftrace_profile *rec;
 641         struct hlist_head *hhd;
 642         struct hlist_node *n;
 643         unsigned long key;
 644
 645         key = hash_long(ip, ftrace_profile_bits);
 646         hhd = &stat->hash[key];
 647
 648         if (hlist_empty(hhd))
 649                 return NULL;
 650
 651         hlist_for_each_entry_rcu(rec, n, hhd, node) {
 652                 if (rec->ip == ip)
 653                         return rec;
 654         }
 655
 656         return NULL;
 657 }
 658
 659 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
 660                                struct ftrace_profile *rec)
 661 {
 662         unsigned long key;
 663
 664         key = hash_long(rec->ip, ftrace_profile_bits);
 665         hlist_add_head_rcu(&rec->node, &stat->hash[key]);
 666 }
 667
 668 /*
 669  * The memory is already allocated, this simply finds a new record to use.
 670  */
 671 static struct ftrace_profile *
 672 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
 673 {
 674         struct ftrace_profile *rec = NULL;
 675
 676         /* prevent recursion (from NMIs) */
 677         if (atomic_inc_return(&stat->disabled) != 1)
 678                 goto out;
 679
 680         /*
 681          * Try to find the function again since an NMI
 682          * could have added it
 683          */
 684         rec = ftrace_find_profiled_func(stat, ip);
 685         if (rec)
 686                 goto out;
 687
 688         if (stat->pages->index == PROFILES_PER_PAGE) {
 689                 if (!stat->pages->next)
 690                         goto out;
 691                 stat->pages = stat->pages->next;
 692         }
 693
 694         rec = &stat->pages->records[stat->pages->index++];
 695         rec->ip = ip;
 696         ftrace_add_profile(stat, rec);
 697
 698  out:
 699         atomic_dec(&stat->disabled);
 700
 701         return rec;
 702 }
 703
 704 static void
 705 function_profile_call(unsigned long ip, unsigned long parent_ip)
 706 {
 707         struct ftrace_profile_stat *stat;
 708         struct ftrace_profile *rec;
 709         unsigned long flags;
 710
 711         if (!ftrace_profile_enabled)
 712                 return;
 713
 714         local_irq_save(flags);
 715
 716         stat = &__get_cpu_var(ftrace_profile_stats);
 717         if (!stat->hash || !ftrace_profile_enabled)
 718                 goto out;
 719
 720         rec = ftrace_find_profiled_func(stat, ip);
 721         if (!rec) {
 722                 rec = ftrace_profile_alloc(stat, ip);
 723                 if (!rec)
 724                         goto out;
 725         }
 726
 727         rec->counter++;
 728  out:
 729         local_irq_restore(flags);
 730 }
 731
 732 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 733 static int profile_graph_entry(struct ftrace_graph_ent *trace)
 734 {
 735         function_profile_call(trace->func, 0);
 736         return 1;
 737 }
 738
 739 static void profile_graph_return(struct ftrace_graph_ret *trace)
 740 {
 741         struct ftrace_profile_stat *stat;
 742         unsigned long long calltime;
 743         struct ftrace_profile *rec;
 744         unsigned long flags;
 745
 746         local_irq_save(flags);
 747         stat = &__get_cpu_var(ftrace_profile_stats);
 748         if (!stat->hash || !ftrace_profile_enabled)
 749                 goto out;
 750
 751         /* If the calltime was zero'd ignore it */
 752         if (!trace->calltime)
 753                 goto out;
 754
 755         calltime = trace->rettime - trace->calltime;
 756
 757         if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
 758                 int index;
 759
 760                 index = trace->depth;
 761
 762                 /* Append this call time to the parent time to subtract */
 763                 if (index)
 764                         current->ret_stack[index - 1].subtime += calltime;
 765
 766                 if (current->ret_stack[index].subtime < calltime)
 767                         calltime -= current->ret_stack[index].subtime;
 768                 else
 769                         calltime = 0;
 770         }
 771
 772         rec = ftrace_find_profiled_func(stat, trace->func);
 773         if (rec) {
 774                 rec->time += calltime;
 775                 rec->time_squared += calltime * calltime;
 776         }
 777
 778  out:
 779         local_irq_restore(flags);
 780 }
 781
 782 static int register_ftrace_profiler(void)
 783 {
 784         return register_ftrace_graph(&profile_graph_return,
 785                                      &profile_graph_entry);
 786 }
 787
 788 static void unregister_ftrace_profiler(void)
 789 {
 790         unregister_ftrace_graph();
 791 }
 792 #else
 793 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
 794         .func           = function_profile_call,
 795 };
 796
 797 static int register_ftrace_profiler(void)
 798 {
 799         return register_ftrace_function(&ftrace_profile_ops);
 800 }
 801
 802 static void unregister_ftrace_profiler(void)
 803 {
 804         unregister_ftrace_function(&ftrace_profile_ops);
 805 }
 806 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 807
 808 static ssize_t
 809 ftrace_profile_write(struct file *filp, const char __user *ubuf,
 810                      size_t cnt, loff_t *ppos)
 811 {
 812         unsigned long val;
 813         int ret;
 814
 815         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
 816         if (ret)
 817                 return ret;
 818
 819         val = !!val;
 820
 821         mutex_lock(&ftrace_profile_lock);
 822         if (ftrace_profile_enabled ^ val) {
 823                 if (val) {
 824                         ret = ftrace_profile_init();
 825                         if (ret < 0) {
 826                                 cnt = ret;
 827                                 goto out;
 828                         }
 829
 830                         ret = register_ftrace_profiler();
 831                         if (ret < 0) {
 832                                 cnt = ret;
 833                                 goto out;
 834                         }
 835                         ftrace_profile_enabled = 1;
 836                 } else {
 837                         ftrace_profile_enabled = 0;
 838                         /*
 839                          * unregister_ftrace_profiler calls stop_machine
 840                          * so this acts like an synchronize_sched.
 841                          */
 842                         unregister_ftrace_profiler();
 843                 }
 844         }
 845  out:
 846         mutex_unlock(&ftrace_profile_lock);
 847
 848         *ppos += cnt;
 849
 850         return cnt;
 851 }
 852
 853 static ssize_t
 854 ftrace_profile_read(struct file *filp, char __user *ubuf,
 855                      size_t cnt, loff_t *ppos)
 856 {
 857         char buf[64];           /* big enough to hold a number */
 858         int r;
 859
 860         r = sprintf(buf, "%u\n", ftrace_profile_enabled);
 861         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 862 }
 863
 864 static const struct file_operations ftrace_profile_fops = {
 865         .open           = tracing_open_generic,
 866         .read           = ftrace_profile_read,
 867         .write          = ftrace_profile_write,
 868         .llseek         = default_llseek,
 869 };
 870
 871 /* used to initialize the real stat files */
 872 static struct tracer_stat function_stats __initdata = {
 873         .name           = "functions",
 874         .stat_start     = function_stat_start,
 875         .stat_next      = function_stat_next,
 876         .stat_cmp       = function_stat_cmp,
 877         .stat_headers   = function_stat_headers,
 878         .stat_show      = function_stat_show
 879 };
 880
 881 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
 882 {
 883         struct ftrace_profile_stat *stat;
 884         struct dentry *entry;
 885         char *name;
 886         int ret;
 887         int cpu;
 888
 889         for_each_possible_cpu(cpu) {
 890                 stat = &per_cpu(ftrace_profile_stats, cpu);
 891
 892                 /* allocate enough for function name + cpu number */
 893                 name = kmalloc(32, GFP_KERNEL);
 894                 if (!name) {
 895                         /*
 896                          * The files created are permanent, if something happens
 897                          * we still do not free memory.
 898                          */
 899                         WARN(1,
 900                              "Could not allocate stat file for cpu %d\n",
 901                              cpu);
 902                         return;
 903                 }
 904                 stat->stat = function_stats;
 905                 snprintf(name, 32, "function%d", cpu);
 906                 stat->stat.name = name;
 907                 ret = register_stat_tracer(&stat->stat);
 908                 if (ret) {
 909                         WARN(1,
 910                              "Could not register function stat for cpu %d\n",
 911                              cpu);
 912                         kfree(name);
 913                         return;
 914                 }
 915         }
 916
 917         entry = debugfs_create_file("function_profile_enabled", 0644,
 918                                     d_tracer, NULL, &ftrace_profile_fops);
 919         if (!entry)
 920                 pr_warning("Could not create debugfs "
 921                            "'function_profile_enabled' entry\n");
 922 }
 923
 924 #else /* CONFIG_FUNCTION_PROFILER */
 925 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
 926 {
 927 }
 928 #endif /* CONFIG_FUNCTION_PROFILER */
 929
 930 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
 931
 932 #ifdef CONFIG_DYNAMIC_FTRACE
 933
 934 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
 935 # error Dynamic ftrace depends on MCOUNT_RECORD
 936 #endif
 937
 938 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
 939
 940 struct ftrace_func_probe {
 941         struct hlist_node       node;
 942         struct ftrace_probe_ops *ops;
 943         unsigned long           flags;
 944         unsigned long           ip;
 945         void                    *data;
 946         struct rcu_head         rcu;
 947 };
 948
 949 enum {
 950         FTRACE_UPDATE_CALLS             = (1 << 0),
 951         FTRACE_DISABLE_CALLS            = (1 << 1),
 952         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 953         FTRACE_START_FUNC_RET           = (1 << 3),
 954         FTRACE_STOP_FUNC_RET            = (1 << 4),
 955 };
 956 struct ftrace_func_entry {
 957         struct hlist_node hlist;
 958         unsigned long ip;
 959 };
 960
 961 struct ftrace_hash {
 962         unsigned long           size_bits;
 963         struct hlist_head       *buckets;
 964         unsigned long           count;
 965         struct rcu_head         rcu;
 966 };
 967
 968 /*
 969  * We make these constant because no one should touch them,
 970  * but they are used as the default "empty hash", to avoid allocating
 971  * it all the time. These are in a read only section such that if
 972  * anyone does try to modify it, it will cause an exception.
 973  */
 974 static const struct hlist_head empty_buckets[1];
 975 static const struct ftrace_hash empty_hash = {
 976         .buckets = (struct hlist_head *)empty_buckets,
 977 };
 978 #define EMPTY_HASH      ((struct ftrace_hash *)&empty_hash)
 979
 980 static struct ftrace_ops global_ops = {
 981         .func                   = ftrace_stub,
 982         .notrace_hash           = EMPTY_HASH,
 983         .filter_hash            = EMPTY_HASH,
 984 };
 985
 986 static struct dyn_ftrace *ftrace_new_addrs;
 987
 988 static DEFINE_MUTEX(ftrace_regex_lock);
 989
 990 struct ftrace_page {
 991         struct ftrace_page      *next;
 992         int                     index;
 993         struct dyn_ftrace       records[];
 994 };
 995
 996 #define ENTRIES_PER_PAGE \
 997   ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
 998
 999 /* estimate from running different kernels */
1000 #define NR_TO_INIT              10000
1001
1002 static struct ftrace_page       *ftrace_pages_start;
1003 static struct ftrace_page       *ftrace_pages;
1004
1005 static struct dyn_ftrace *ftrace_free_records;
1006
1007 static struct ftrace_func_entry *
1008 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1009 {
1010         unsigned long key;
1011         struct ftrace_func_entry *entry;
1012         struct hlist_head *hhd;
1013         struct hlist_node *n;
1014
1015         if (!hash->count)
1016                 return NULL;
1017
1018         if (hash->size_bits > 0)
1019                 key = hash_long(ip, hash->size_bits);
1020         else
1021                 key = 0;
1022
1023         hhd = &hash->buckets[key];
1024
1025         hlist_for_each_entry_rcu(entry, n, hhd, hlist) {
1026                 if (entry->ip == ip)
1027                         return entry;
1028         }
1029         return NULL;
1030 }
1031
1032 static void __add_hash_entry(struct ftrace_hash *hash,
1033                              struct ftrace_func_entry *entry)
1034 {
1035         struct hlist_head *hhd;
1036         unsigned long key;
1037
1038         if (hash->size_bits)
1039                 key = hash_long(entry->ip, hash->size_bits);
1040         else
1041                 key = 0;
1042
1043         hhd = &hash->buckets[key];
1044         hlist_add_head(&entry->hlist, hhd);
1045         hash->count++;
1046 }
1047
1048 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1049 {
1050         struct ftrace_func_entry *entry;
1051
1052         entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1053         if (!entry)
1054                 return -ENOMEM;
1055
1056         entry->ip = ip;
1057         __add_hash_entry(hash, entry);
1058
1059         return 0;
1060 }
1061
1062 static void
1063 free_hash_entry(struct ftrace_hash *hash,
1064                   struct ftrace_func_entry *entry)
1065 {
1066         hlist_del(&entry->hlist);
1067         kfree(entry);
1068         hash->count--;
1069 }
1070
1071 static void
1072 remove_hash_entry(struct ftrace_hash *hash,
1073                   struct ftrace_func_entry *entry)
1074 {
1075         hlist_del(&entry->hlist);
1076         hash->count--;
1077 }
1078
1079 static void ftrace_hash_clear(struct ftrace_hash *hash)
1080 {
1081         struct hlist_head *hhd;
1082         struct hlist_node *tp, *tn;
1083         struct ftrace_func_entry *entry;
1084         int size = 1 << hash->size_bits;
1085         int i;
1086
1087         if (!hash->count)
1088                 return;
1089
1090         for (i = 0; i < size; i++) {
1091                 hhd = &hash->buckets[i];
1092                 hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist)
1093                         free_hash_entry(hash, entry);
1094         }
1095         FTRACE_WARN_ON(hash->count);
1096 }
1097
1098 static void free_ftrace_hash(struct ftrace_hash *hash)
1099 {
1100         if (!hash || hash == EMPTY_HASH)
1101                 return;
1102         ftrace_hash_clear(hash);
1103         kfree(hash->buckets);
1104         kfree(hash);
1105 }
1106
1107 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1108 {
1109         struct ftrace_hash *hash;
1110
1111         hash = container_of(rcu, struct ftrace_hash, rcu);
1112         free_ftrace_hash(hash);
1113 }
1114
1115 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1116 {
1117         if (!hash || hash == EMPTY_HASH)
1118                 return;
1119         call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1120 }
1121
1122 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1123 {
1124         struct ftrace_hash *hash;
1125         int size;
1126
1127         hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1128         if (!hash)
1129                 return NULL;
1130
1131         size = 1 << size_bits;
1132         hash->buckets = kzalloc(sizeof(*hash->buckets) * size, GFP_KERNEL);
1133
1134         if (!hash->buckets) {
1135                 kfree(hash);
1136                 return NULL;
1137         }
1138
1139         hash->size_bits = size_bits;
1140
1141         return hash;
1142 }
1143
1144 static struct ftrace_hash *
1145 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1146 {
1147         struct ftrace_func_entry *entry;
1148         struct ftrace_hash *new_hash;
1149         struct hlist_node *tp;
1150         int size;
1151         int ret;
1152         int i;
1153
1154         new_hash = alloc_ftrace_hash(size_bits);
1155         if (!new_hash)
1156                 return NULL;
1157
1158         /* Empty hash? */
1159         if (!hash || !hash->count)
1160                 return new_hash;
1161
1162         size = 1 << hash->size_bits;
1163         for (i = 0; i < size; i++) {
1164                 hlist_for_each_entry(entry, tp, &hash->buckets[i], hlist) {
1165                         ret = add_hash_entry(new_hash, entry->ip);
1166                         if (ret < 0)
1167                                 goto free_hash;
1168                 }
1169         }
1170
1171         FTRACE_WARN_ON(new_hash->count != hash->count);
1172
1173         return new_hash;
1174
1175  free_hash:
1176         free_ftrace_hash(new_hash);
1177         return NULL;
1178 }
1179
1180 static void
1181 ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
1182 static void
1183 ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
1184
1185 static int
1186 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1187                  struct ftrace_hash **dst, struct ftrace_hash *src)
1188 {
1189         struct ftrace_func_entry *entry;
1190         struct hlist_node *tp, *tn;
1191         struct hlist_head *hhd;
1192         struct ftrace_hash *old_hash;
1193         struct ftrace_hash *new_hash;
1194         unsigned long key;
1195         int size = src->count;
1196         int bits = 0;
1197         int ret;
1198         int i;
1199
1200         /*
1201          * Remove the current set, update the hash and add
1202          * them back.
1203          */
1204         ftrace_hash_rec_disable(ops, enable);
1205
1206         /*
1207          * If the new source is empty, just free dst and assign it
1208          * the empty_hash.
1209          */
1210         if (!src->count) {
1211                 free_ftrace_hash_rcu(*dst);
1212                 rcu_assign_pointer(*dst, EMPTY_HASH);
1213                 /* still need to update the function records */
1214                 ret = 0;
1215                 goto out;
1216         }
1217
1218         /*
1219          * Make the hash size about 1/2 the # found
1220          */
1221         for (size /= 2; size; size >>= 1)
1222                 bits++;
1223
1224         /* Don't allocate too much */
1225         if (bits > FTRACE_HASH_MAX_BITS)
1226                 bits = FTRACE_HASH_MAX_BITS;
1227
1228         ret = -ENOMEM;
1229         new_hash = alloc_ftrace_hash(bits);
1230         if (!new_hash)
1231                 goto out;
1232
1233         size = 1 << src->size_bits;
1234         for (i = 0; i < size; i++) {
1235                 hhd = &src->buckets[i];
1236                 hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist) {
1237                         if (bits > 0)
1238                                 key = hash_long(entry->ip, bits);
1239                         else
1240                                 key = 0;
1241                         remove_hash_entry(src, entry);
1242                         __add_hash_entry(new_hash, entry);
1243                 }
1244         }
1245
1246         old_hash = *dst;
1247         rcu_assign_pointer(*dst, new_hash);
1248         free_ftrace_hash_rcu(old_hash);
1249
1250         ret = 0;
1251  out:
1252         /*
1253          * Enable regardless of ret:
1254          *  On success, we enable the new hash.
1255          *  On failure, we re-enable the original hash.
1256          */
1257         ftrace_hash_rec_enable(ops, enable);
1258
1259         return ret;
1260 }
1261
1262 /*
1263  * Test the hashes for this ops to see if we want to call
1264  * the ops->func or not.
1265  *
1266  * It's a match if the ip is in the ops->filter_hash or
1267  * the filter_hash does not exist or is empty,
1268  *  AND
1269  * the ip is not in the ops->notrace_hash.
1270  *
1271  * This needs to be called with preemption disabled as
1272  * the hashes are freed with call_rcu_sched().
1273  */
1274 static int
1275 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
1276 {
1277         struct ftrace_hash *filter_hash;
1278         struct ftrace_hash *notrace_hash;
1279         int ret;
1280
1281         filter_hash = rcu_dereference_raw(ops->filter_hash);
1282         notrace_hash = rcu_dereference_raw(ops->notrace_hash);
1283
1284         if ((!filter_hash || !filter_hash->count ||
1285              ftrace_lookup_ip(filter_hash, ip)) &&
1286             (!notrace_hash || !notrace_hash->count ||
1287              !ftrace_lookup_ip(notrace_hash, ip)))
1288                 ret = 1;
1289         else
1290                 ret = 0;
1291
1292         return ret;
1293 }
1294
1295 /*
1296  * This is a double for. Do not use 'break' to break out of the loop,
1297  * you must use a goto.
1298  */
1299 #define do_for_each_ftrace_rec(pg, rec)                                 \
1300         for (pg = ftrace_pages_start; pg; pg = pg->next) {              \
1301                 int _____i;                                             \
1302                 for (_____i = 0; _____i < pg->index; _____i++) {        \
1303                         rec = &pg->records[_____i];
1304
1305 #define while_for_each_ftrace_rec()             \
1306                 }                               \
1307         }
1308
1309 static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
1310                                      int filter_hash,
1311                                      bool inc)
1312 {
1313         struct ftrace_hash *hash;
1314         struct ftrace_hash *other_hash;
1315         struct ftrace_page *pg;
1316         struct dyn_ftrace *rec;
1317         int count = 0;
1318         int all = 0;
1319
1320         /* Only update if the ops has been registered */
1321         if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1322                 return;
1323
1324         /*
1325          * In the filter_hash case:
1326          *   If the count is zero, we update all records.
1327          *   Otherwise we just update the items in the hash.
1328          *
1329          * In the notrace_hash case:
1330          *   We enable the update in the hash.
1331          *   As disabling notrace means enabling the tracing,
1332          *   and enabling notrace means disabling, the inc variable
1333          *   gets inversed.
1334          */
1335         if (filter_hash) {
1336                 hash = ops->filter_hash;
1337                 other_hash = ops->notrace_hash;
1338                 if (!hash || !hash->count)
1339                         all = 1;
1340         } else {
1341                 inc = !inc;
1342                 hash = ops->notrace_hash;
1343                 other_hash = ops->filter_hash;
1344                 /*
1345                  * If the notrace hash has no items,
1346                  * then there's nothing to do.
1347                  */
1348                 if (hash && !hash->count)
1349                         return;
1350         }
1351
1352         do_for_each_ftrace_rec(pg, rec) {
1353                 int in_other_hash = 0;
1354                 int in_hash = 0;
1355                 int match = 0;
1356
1357                 if (all) {
1358                         /*
1359                          * Only the filter_hash affects all records.
1360                          * Update if the record is not in the notrace hash.
1361                          */
1362                         if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1363                                 match = 1;
1364                 } else {
1365                         in_hash = hash && !!ftrace_lookup_ip(hash, rec->ip);
1366                         in_other_hash = other_hash && !!ftrace_lookup_ip(other_hash, rec->ip);
1367
1368                         /*
1369                          *
1370                          */
1371                         if (filter_hash && in_hash && !in_other_hash)
1372                                 match = 1;
1373                         else if (!filter_hash && in_hash &&
1374                                  (in_other_hash || !other_hash->count))
1375                                 match = 1;
1376                 }
1377                 if (!match)
1378                         continue;
1379
1380                 if (inc) {
1381                         rec->flags++;
1382                         if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
1383                                 return;
1384                 } else {
1385                         if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
1386                                 return;
1387                         rec->flags--;
1388                 }
1389                 count++;
1390                 /* Shortcut, if we handled all records, we are done. */
1391                 if (!all && count == hash->count)
1392                         return;
1393         } while_for_each_ftrace_rec();
1394 }
1395
1396 static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1397                                     int filter_hash)
1398 {
1399         __ftrace_hash_rec_update(ops, filter_hash, 0);
1400 }
1401
1402 static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1403                                    int filter_hash)
1404 {
1405         __ftrace_hash_rec_update(ops, filter_hash, 1);
1406 }
1407
1408 static void ftrace_free_rec(struct dyn_ftrace *rec)
1409 {
1410         rec->freelist = ftrace_free_records;
1411         ftrace_free_records = rec;
1412         rec->flags |= FTRACE_FL_FREE;
1413 }
1414
1415 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
1416 {
1417         struct dyn_ftrace *rec;
1418
1419         /* First check for freed records */
1420         if (ftrace_free_records) {
1421                 rec = ftrace_free_records;
1422
1423                 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
1424                         FTRACE_WARN_ON_ONCE(1);
1425                         ftrace_free_records = NULL;
1426                         return NULL;
1427                 }
1428
1429                 ftrace_free_records = rec->freelist;
1430                 memset(rec, 0, sizeof(*rec));
1431                 return rec;
1432         }
1433
1434         if (ftrace_pages->index == ENTRIES_PER_PAGE) {
1435                 if (!ftrace_pages->next) {
1436                         /* allocate another page */
1437                         ftrace_pages->next =
1438                                 (void *)get_zeroed_page(GFP_KERNEL);
1439                         if (!ftrace_pages->next)
1440                                 return NULL;
1441                 }
1442                 ftrace_pages = ftrace_pages->next;
1443         }
1444
1445         return &ftrace_pages->records[ftrace_pages->index++];
1446 }
1447
1448 static struct dyn_ftrace *
1449 ftrace_record_ip(unsigned long ip)
1450 {
1451         struct dyn_ftrace *rec;
1452
1453         if (ftrace_disabled)
1454                 return NULL;
1455
1456         rec = ftrace_alloc_dyn_node(ip);
1457         if (!rec)
1458                 return NULL;
1459
1460         rec->ip = ip;
1461         rec->newlist = ftrace_new_addrs;
1462         ftrace_new_addrs = rec;
1463
1464         return rec;
1465 }
1466
1467 static void print_ip_ins(const char *fmt, unsigned char *p)
1468 {
1469         int i;
1470
1471         printk(KERN_CONT "%s", fmt);
1472
1473         for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1474                 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1475 }
1476
1477 static void ftrace_bug(int failed, unsigned long ip)
1478 {
1479         switch (failed) {
1480         case -EFAULT:
1481                 FTRACE_WARN_ON_ONCE(1);
1482                 pr_info("ftrace faulted on modifying ");
1483                 print_ip_sym(ip);
1484                 break;
1485         case -EINVAL:
1486                 FTRACE_WARN_ON_ONCE(1);
1487                 pr_info("ftrace failed to modify ");
1488                 print_ip_sym(ip);
1489                 print_ip_ins(" actual: ", (unsigned char *)ip);
1490                 printk(KERN_CONT "\n");
1491                 break;
1492         case -EPERM:
1493                 FTRACE_WARN_ON_ONCE(1);
1494                 pr_info("ftrace faulted on writing ");
1495                 print_ip_sym(ip);
1496                 break;
1497         default:
1498                 FTRACE_WARN_ON_ONCE(1);
1499                 pr_info("ftrace faulted on unknown error ");
1500                 print_ip_sym(ip);
1501         }
1502 }
1503
1504
1505 /* Return 1 if the address range is reserved for ftrace */
1506 int ftrace_text_reserved(void *start, void *end)
1507 {
1508         struct dyn_ftrace *rec;
1509         struct ftrace_page *pg;
1510
1511         do_for_each_ftrace_rec(pg, rec) {
1512                 if (rec->ip <= (unsigned long)end &&
1513                     rec->ip + MCOUNT_INSN_SIZE > (unsigned long)start)
1514                         return 1;
1515         } while_for_each_ftrace_rec();
1516         return 0;
1517 }
1518
1519
1520 static int
1521 __ftrace_replace_code(struct dyn_ftrace *rec, int update)
1522 {
1523         unsigned long ftrace_addr;
1524         unsigned long flag = 0UL;
1525
1526         ftrace_addr = (unsigned long)FTRACE_ADDR;
1527
1528         /*
1529          * If we are updating calls:
1530          *
1531          *   If the record has a ref count, then we need to enable it
1532          *   because someone is using it.
1533          *
1534          *   Otherwise we make sure its disabled.
1535          *
1536          * If we are disabling calls, then disable all records that
1537          * are enabled.
1538          */
1539         if (update && (rec->flags & ~FTRACE_FL_MASK))
1540                 flag = FTRACE_FL_ENABLED;
1541
1542         /* If the state of this record hasn't changed, then do nothing */
1543         if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1544                 return 0;
1545
1546         if (flag) {
1547                 rec->flags |= FTRACE_FL_ENABLED;
1548                 return ftrace_make_call(rec, ftrace_addr);
1549         }
1550
1551         rec->flags &= ~FTRACE_FL_ENABLED;
1552         return ftrace_make_nop(NULL, rec, ftrace_addr);
1553 }
1554
1555 static void ftrace_replace_code(int update)
1556 {
1557         struct dyn_ftrace *rec;
1558         struct ftrace_page *pg;
1559         int failed;
1560
1561         if (unlikely(ftrace_disabled))
1562                 return;
1563
1564         do_for_each_ftrace_rec(pg, rec) {
1565                 /* Skip over free records */
1566                 if (rec->flags & FTRACE_FL_FREE)
1567                         continue;
1568
1569                 failed = __ftrace_replace_code(rec, update);
1570                 if (failed) {
1571                         ftrace_bug(failed, rec->ip);
1572                         /* Stop processing */
1573                         return;
1574                 }
1575         } while_for_each_ftrace_rec();
1576 }
1577
1578 static int
1579 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1580 {
1581         unsigned long ip;
1582         int ret;
1583
1584         ip = rec->ip;
1585
1586         if (unlikely(ftrace_disabled))
1587                 return 0;
1588
1589         ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1590         if (ret) {
1591                 ftrace_bug(ret, ip);
1592                 return 0;
1593         }
1594         return 1;
1595 }
1596
1597 /*
1598  * archs can override this function if they must do something
1599  * before the modifying code is performed.
1600  */
1601 int __weak ftrace_arch_code_modify_prepare(void)
1602 {
1603         return 0;
1604 }
1605
1606 /*
1607  * archs can override this function if they must do something
1608  * after the modifying code is performed.
1609  */
1610 int __weak ftrace_arch_code_modify_post_process(void)
1611 {
1612         return 0;
1613 }
1614
1615 static int __ftrace_modify_code(void *data)
1616 {
1617         int *command = data;
1618
1619         /*
1620          * Do not call function tracer while we update the code.
1621          * We are in stop machine, no worrying about races.
1622          */
1623         function_trace_stop++;
1624
1625         if (*command & FTRACE_UPDATE_CALLS)
1626                 ftrace_replace_code(1);
1627         else if (*command & FTRACE_DISABLE_CALLS)
1628                 ftrace_replace_code(0);
1629
1630         if (*command & FTRACE_UPDATE_TRACE_FUNC)
1631                 ftrace_update_ftrace_func(ftrace_trace_function);
1632
1633         if (*command & FTRACE_START_FUNC_RET)
1634                 ftrace_enable_ftrace_graph_caller();
1635         else if (*command & FTRACE_STOP_FUNC_RET)
1636                 ftrace_disable_ftrace_graph_caller();
1637
1638 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
1639         /*
1640          * For archs that call ftrace_test_stop_func(), we must
1641          * wait till after we update all the function callers
1642          * before we update the callback. This keeps different
1643          * ops that record different functions from corrupting
1644          * each other.
1645          */
1646         __ftrace_trace_function = __ftrace_trace_function_delay;
1647 #endif
1648         function_trace_stop--;
1649
1650         return 0;
1651 }
1652
1653 static void ftrace_run_update_code(int command)
1654 {
1655         int ret;
1656
1657         ret = ftrace_arch_code_modify_prepare();
1658         FTRACE_WARN_ON(ret);
1659         if (ret)
1660                 return;
1661
1662         stop_machine(__ftrace_modify_code, &command, NULL);
1663
1664         ret = ftrace_arch_code_modify_post_process();
1665         FTRACE_WARN_ON(ret);
1666 }
1667
1668 static ftrace_func_t saved_ftrace_func;
1669 static int ftrace_start_up;
1670 static int global_start_up;
1671
1672 static void ftrace_startup_enable(int command)
1673 {
1674         if (saved_ftrace_func != ftrace_trace_function) {
1675                 saved_ftrace_func = ftrace_trace_function;
1676                 command |= FTRACE_UPDATE_TRACE_FUNC;
1677         }
1678
1679         if (!command || !ftrace_enabled)
1680                 return;
1681
1682         ftrace_run_update_code(command);
1683 }
1684
1685 static int ftrace_startup(struct ftrace_ops *ops, int command)
1686 {
1687         bool hash_enable = true;
1688
1689         if (unlikely(ftrace_disabled))
1690                 return -ENODEV;
1691
1692         ftrace_start_up++;
1693         command |= FTRACE_UPDATE_CALLS;
1694
1695         /* ops marked global share the filter hashes */
1696         if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1697                 ops = &global_ops;
1698                 /* Don't update hash if global is already set */
1699                 if (global_start_up)
1700                         hash_enable = false;
1701                 global_start_up++;
1702         }
1703
1704         ops->flags |= FTRACE_OPS_FL_ENABLED;
1705         if (hash_enable)
1706                 ftrace_hash_rec_enable(ops, 1);
1707
1708         ftrace_startup_enable(command);
1709
1710         return 0;
1711 }
1712
1713 static void ftrace_shutdown(struct ftrace_ops *ops, int command)
1714 {
1715         bool hash_disable = true;
1716
1717         if (unlikely(ftrace_disabled))
1718                 return;
1719
1720         ftrace_start_up--;
1721         /*
1722          * Just warn in case of unbalance, no need to kill ftrace, it's not
1723          * critical but the ftrace_call callers may be never nopped again after
1724          * further ftrace uses.
1725          */
1726         WARN_ON_ONCE(ftrace_start_up < 0);
1727
1728         if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1729                 ops = &global_ops;
1730                 global_start_up--;
1731                 WARN_ON_ONCE(global_start_up < 0);
1732                 /* Don't update hash if global still has users */
1733                 if (global_start_up) {
1734                         WARN_ON_ONCE(!ftrace_start_up);
1735                         hash_disable = false;
1736                 }
1737         }
1738
1739         if (hash_disable)
1740                 ftrace_hash_rec_disable(ops, 1);
1741
1742         if (ops != &global_ops || !global_start_up)
1743                 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
1744
1745         command |= FTRACE_UPDATE_CALLS;
1746
1747         if (saved_ftrace_func != ftrace_trace_function) {
1748                 saved_ftrace_func = ftrace_trace_function;
1749                 command |= FTRACE_UPDATE_TRACE_FUNC;
1750         }
1751
1752         if (!command || !ftrace_enabled)
1753                 return;
1754
1755         ftrace_run_update_code(command);
1756 }
1757
1758 static void ftrace_startup_sysctl(void)
1759 {
1760         if (unlikely(ftrace_disabled))
1761                 return;
1762
1763         /* Force update next time */
1764         saved_ftrace_func = NULL;
1765         /* ftrace_start_up is true if we want ftrace running */
1766         if (ftrace_start_up)
1767                 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
1768 }
1769
1770 static void ftrace_shutdown_sysctl(void)
1771 {
1772         if (unlikely(ftrace_disabled))
1773                 return;
1774
1775         /* ftrace_start_up is true if ftrace is running */
1776         if (ftrace_start_up)
1777                 ftrace_run_update_code(FTRACE_DISABLE_CALLS);
1778 }
1779
1780 static cycle_t          ftrace_update_time;
1781 static unsigned long    ftrace_update_cnt;
1782 unsigned long           ftrace_update_tot_cnt;
1783
1784 static int ops_traces_mod(struct ftrace_ops *ops)
1785 {
1786         struct ftrace_hash *hash;
1787
1788         hash = ops->filter_hash;
1789         return !!(!hash || !hash->count);
1790 }
1791
1792 static int ftrace_update_code(struct module *mod)
1793 {
1794         struct dyn_ftrace *p;
1795         cycle_t start, stop;
1796         unsigned long ref = 0;
1797
1798         /*
1799          * When adding a module, we need to check if tracers are
1800          * currently enabled and if they are set to trace all functions.
1801          * If they are, we need to enable the module functions as well
1802          * as update the reference counts for those function records.
1803          */
1804         if (mod) {
1805                 struct ftrace_ops *ops;
1806
1807                 for (ops = ftrace_ops_list;
1808                      ops != &ftrace_list_end; ops = ops->next) {
1809                         if (ops->flags & FTRACE_OPS_FL_ENABLED &&
1810                             ops_traces_mod(ops))
1811                                 ref++;
1812                 }
1813         }
1814
1815         start = ftrace_now(raw_smp_processor_id());
1816         ftrace_update_cnt = 0;
1817
1818         while (ftrace_new_addrs) {
1819
1820                 /* If something went wrong, bail without enabling anything */
1821                 if (unlikely(ftrace_disabled))
1822                         return -1;
1823
1824                 p = ftrace_new_addrs;
1825                 ftrace_new_addrs = p->newlist;
1826                 p->flags = ref;
1827
1828                 /*
1829                  * Do the initial record conversion from mcount jump
1830                  * to the NOP instructions.
1831                  */
1832                 if (!ftrace_code_disable(mod, p)) {
1833                         ftrace_free_rec(p);
1834                         /* Game over */
1835                         break;
1836                 }
1837
1838                 ftrace_update_cnt++;
1839
1840                 /*
1841                  * If the tracing is enabled, go ahead and enable the record.
1842                  *
1843                  * The reason not to enable the record immediatelly is the
1844                  * inherent check of ftrace_make_nop/ftrace_make_call for
1845                  * correct previous instructions.  Making first the NOP
1846                  * conversion puts the module to the correct state, thus
1847                  * passing the ftrace_make_call check.
1848                  */
1849                 if (ftrace_start_up && ref) {
1850                         int failed = __ftrace_replace_code(p, 1);
1851                         if (failed) {
1852                                 ftrace_bug(failed, p->ip);
1853                                 ftrace_free_rec(p);
1854                         }
1855                 }
1856         }
1857
1858         stop = ftrace_now(raw_smp_processor_id());
1859         ftrace_update_time = stop - start;
1860         ftrace_update_tot_cnt += ftrace_update_cnt;
1861
1862         return 0;
1863 }
1864
1865 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
1866 {
1867         struct ftrace_page *pg;
1868         int cnt;
1869         int i;
1870
1871         /* allocate a few pages */
1872         ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
1873         if (!ftrace_pages_start)
1874                 return -1;
1875
1876         /*
1877          * Allocate a few more pages.
1878          *
1879          * TODO: have some parser search vmlinux before
1880          *   final linking to find all calls to ftrace.
1881          *   Then we can:
1882          *    a) know how many pages to allocate.
1883          *     and/or
1884          *    b) set up the table then.
1885          *
1886          *  The dynamic code is still necessary for
1887          *  modules.
1888          */
1889
1890         pg = ftrace_pages = ftrace_pages_start;
1891
1892         cnt = num_to_init / ENTRIES_PER_PAGE;
1893         pr_info("ftrace: allocating %ld entries in %d pages\n",
1894                 num_to_init, cnt + 1);
1895
1896         for (i = 0; i < cnt; i++) {
1897                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
1898
1899                 /* If we fail, we'll try later anyway */
1900                 if (!pg->next)
1901                         break;
1902
1903                 pg = pg->next;
1904         }
1905
1906         return 0;
1907 }
1908
1909 enum {
1910         FTRACE_ITER_FILTER      = (1 << 0),
1911         FTRACE_ITER_NOTRACE     = (1 << 1),
1912         FTRACE_ITER_PRINTALL    = (1 << 2),
1913         FTRACE_ITER_HASH        = (1 << 3),
1914         FTRACE_ITER_ENABLED     = (1 << 4),
1915 };
1916
1917 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1918
1919 struct ftrace_iterator {
1920         loff_t                          pos;
1921         loff_t                          func_pos;
1922         struct ftrace_page              *pg;
1923         struct dyn_ftrace               *func;
1924         struct ftrace_func_probe        *probe;
1925         struct trace_parser             parser;
1926         struct ftrace_hash              *hash;
1927         struct ftrace_ops               *ops;
1928         int                             hidx;
1929         int                             idx;
1930         unsigned                        flags;
1931 };
1932
1933 static void *
1934 t_hash_next(struct seq_file *m, loff_t *pos)
1935 {
1936         struct ftrace_iterator *iter = m->private;
1937         struct hlist_node *hnd = NULL;
1938         struct hlist_head *hhd;
1939
1940         (*pos)++;
1941         iter->pos = *pos;
1942
1943         if (iter->probe)
1944                 hnd = &iter->probe->node;
1945  retry:
1946         if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
1947                 return NULL;
1948
1949         hhd = &ftrace_func_hash[iter->hidx];
1950
1951         if (hlist_empty(hhd)) {
1952                 iter->hidx++;
1953                 hnd = NULL;
1954                 goto retry;
1955         }
1956
1957         if (!hnd)
1958                 hnd = hhd->first;
1959         else {
1960                 hnd = hnd->next;
1961                 if (!hnd) {
1962                         iter->hidx++;
1963                         goto retry;
1964                 }
1965         }
1966
1967         if (WARN_ON_ONCE(!hnd))
1968                 return NULL;
1969
1970         iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
1971
1972         return iter;
1973 }
1974
1975 static void *t_hash_start(struct seq_file *m, loff_t *pos)
1976 {
1977         struct ftrace_iterator *iter = m->private;
1978         void *p = NULL;
1979         loff_t l;
1980
1981         if (iter->func_pos > *pos)
1982                 return NULL;
1983
1984         iter->hidx = 0;
1985         for (l = 0; l <= (*pos - iter->func_pos); ) {
1986                 p = t_hash_next(m, &l);
1987                 if (!p)
1988                         break;
1989         }
1990         if (!p)
1991                 return NULL;
1992
1993         /* Only set this if we have an item */
1994         iter->flags |= FTRACE_ITER_HASH;
1995
1996         return iter;
1997 }
1998
1999 static int
2000 t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
2001 {
2002         struct ftrace_func_probe *rec;
2003
2004         rec = iter->probe;
2005         if (WARN_ON_ONCE(!rec))
2006                 return -EIO;
2007
2008         if (rec->ops->print)
2009                 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
2010
2011         seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
2012
2013         if (rec->data)
2014                 seq_printf(m, ":%p", rec->data);
2015         seq_putc(m, '\n');
2016
2017         return 0;
2018 }
2019
2020 static void *
2021 t_next(struct seq_file *m, void *v, loff_t *pos)
2022 {
2023         struct ftrace_iterator *iter = m->private;
2024         struct ftrace_ops *ops = &global_ops;
2025         struct dyn_ftrace *rec = NULL;
2026
2027         if (unlikely(ftrace_disabled))
2028                 return NULL;
2029
2030         if (iter->flags & FTRACE_ITER_HASH)
2031                 return t_hash_next(m, pos);
2032
2033         (*pos)++;
2034         iter->pos = iter->func_pos = *pos;
2035
2036         if (iter->flags & FTRACE_ITER_PRINTALL)
2037                 return t_hash_start(m, pos);
2038
2039  retry:
2040         if (iter->idx >= iter->pg->index) {
2041                 if (iter->pg->next) {
2042                         iter->pg = iter->pg->next;
2043                         iter->idx = 0;
2044                         goto retry;
2045                 }
2046         } else {
2047                 rec = &iter->pg->records[iter->idx++];
2048                 if ((rec->flags & FTRACE_FL_FREE) ||
2049
2050                     ((iter->flags & FTRACE_ITER_FILTER) &&
2051                      !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
2052
2053                     ((iter->flags & FTRACE_ITER_NOTRACE) &&
2054                      !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
2055
2056                     ((iter->flags & FTRACE_ITER_ENABLED) &&
2057                      !(rec->flags & ~FTRACE_FL_MASK))) {
2058
2059                         rec = NULL;
2060                         goto retry;
2061                 }
2062         }
2063
2064         if (!rec)
2065                 return t_hash_start(m, pos);
2066
2067         iter->func = rec;
2068
2069         return iter;
2070 }
2071
2072 static void reset_iter_read(struct ftrace_iterator *iter)
2073 {
2074         iter->pos = 0;
2075         iter->func_pos = 0;
2076         iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH);
2077 }
2078
2079 static void *t_start(struct seq_file *m, loff_t *pos)
2080 {
2081         struct ftrace_iterator *iter = m->private;
2082         struct ftrace_ops *ops = &global_ops;
2083         void *p = NULL;
2084         loff_t l;
2085
2086         mutex_lock(&ftrace_lock);
2087
2088         if (unlikely(ftrace_disabled))
2089                 return NULL;
2090
2091         /*
2092          * If an lseek was done, then reset and start from beginning.
2093          */
2094         if (*pos < iter->pos)
2095                 reset_iter_read(iter);
2096
2097         /*
2098          * For set_ftrace_filter reading, if we have the filter
2099          * off, we can short cut and just print out that all
2100          * functions are enabled.
2101          */
2102         if (iter->flags & FTRACE_ITER_FILTER && !ops->filter_hash->count) {
2103                 if (*pos > 0)
2104                         return t_hash_start(m, pos);
2105                 iter->flags |= FTRACE_ITER_PRINTALL;
2106                 /* reset in case of seek/pread */
2107                 iter->flags &= ~FTRACE_ITER_HASH;
2108                 return iter;
2109         }
2110
2111         if (iter->flags & FTRACE_ITER_HASH)
2112                 return t_hash_start(m, pos);
2113
2114         /*
2115          * Unfortunately, we need to restart at ftrace_pages_start
2116          * every time we let go of the ftrace_mutex. This is because
2117          * those pointers can change without the lock.
2118          */
2119         iter->pg = ftrace_pages_start;
2120         iter->idx = 0;
2121         for (l = 0; l <= *pos; ) {
2122                 p = t_next(m, p, &l);
2123                 if (!p)
2124                         break;
2125         }
2126
2127         if (!p) {
2128                 if (iter->flags & FTRACE_ITER_FILTER)
2129                         return t_hash_start(m, pos);
2130
2131                 return NULL;
2132         }
2133
2134         return iter;
2135 }
2136
2137 static void t_stop(struct seq_file *m, void *p)
2138 {
2139         mutex_unlock(&ftrace_lock);
2140 }
2141
2142 static int t_show(struct seq_file *m, void *v)
2143 {
2144         struct ftrace_iterator *iter = m->private;
2145         struct dyn_ftrace *rec;
2146
2147         if (iter->flags & FTRACE_ITER_HASH)
2148                 return t_hash_show(m, iter);
2149
2150         if (iter->flags & FTRACE_ITER_PRINTALL) {
2151                 seq_printf(m, "#### all functions enabled ####\n");
2152                 return 0;
2153         }
2154
2155         rec = iter->func;
2156
2157         if (!rec)
2158                 return 0;
2159
2160         seq_printf(m, "%ps", (void *)rec->ip);
2161         if (iter->flags & FTRACE_ITER_ENABLED)
2162                 seq_printf(m, " (%ld)",
2163                            rec->flags & ~FTRACE_FL_MASK);
2164         seq_printf(m, "\n");
2165
2166         return 0;
2167 }
2168
2169 static const struct seq_operations show_ftrace_seq_ops = {
2170         .start = t_start,
2171         .next = t_next,
2172         .stop = t_stop,
2173         .show = t_show,
2174 };
2175
2176 static int
2177 ftrace_avail_open(struct inode *inode, struct file *file)
2178 {
2179         struct ftrace_iterator *iter;
2180         int ret;
2181
2182         if (unlikely(ftrace_disabled))
2183                 return -ENODEV;
2184
2185         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2186         if (!iter)
2187                 return -ENOMEM;
2188
2189         iter->pg = ftrace_pages_start;
2190
2191         ret = seq_open(file, &show_ftrace_seq_ops);
2192         if (!ret) {
2193                 struct seq_file *m = file->private_data;
2194
2195                 m->private = iter;
2196         } else {
2197                 kfree(iter);
2198         }
2199
2200         return ret;
2201 }
2202
2203 static int
2204 ftrace_enabled_open(struct inode *inode, struct file *file)
2205 {
2206         struct ftrace_iterator *iter;
2207         int ret;
2208
2209         if (unlikely(ftrace_disabled))
2210                 return -ENODEV;
2211
2212         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2213         if (!iter)
2214                 return -ENOMEM;
2215
2216         iter->pg = ftrace_pages_start;
2217         iter->flags = FTRACE_ITER_ENABLED;
2218
2219         ret = seq_open(file, &show_ftrace_seq_ops);
2220         if (!ret) {
2221                 struct seq_file *m = file->private_data;
2222
2223                 m->private = iter;
2224         } else {
2225                 kfree(iter);
2226         }
2227
2228         return ret;
2229 }
2230
2231 static void ftrace_filter_reset(struct ftrace_hash *hash)
2232 {
2233         mutex_lock(&ftrace_lock);
2234         ftrace_hash_clear(hash);
2235         mutex_unlock(&ftrace_lock);
2236 }
2237
2238 static int
2239 ftrace_regex_open(struct ftrace_ops *ops, int flag,
2240                   struct inode *inode, struct file *file)
2241 {
2242         struct ftrace_iterator *iter;
2243         struct ftrace_hash *hash;
2244         int ret = 0;
2245
2246         if (unlikely(ftrace_disabled))
2247                 return -ENODEV;
2248
2249         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2250         if (!iter)
2251                 return -ENOMEM;
2252
2253         if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
2254                 kfree(iter);
2255                 return -ENOMEM;
2256         }
2257
2258         if (flag & FTRACE_ITER_NOTRACE)
2259                 hash = ops->notrace_hash;
2260         else
2261                 hash = ops->filter_hash;
2262
2263         iter->ops = ops;
2264         iter->flags = flag;
2265
2266         if (file->f_mode & FMODE_WRITE) {
2267                 mutex_lock(&ftrace_lock);
2268                 iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
2269                 mutex_unlock(&ftrace_lock);
2270
2271                 if (!iter->hash) {
2272                         trace_parser_put(&iter->parser);
2273                         kfree(iter);
2274                         return -ENOMEM;
2275                 }
2276         }
2277
2278         mutex_lock(&ftrace_regex_lock);
2279
2280         if ((file->f_mode & FMODE_WRITE) &&
2281             (file->f_flags & O_TRUNC))
2282                 ftrace_filter_reset(iter->hash);
2283
2284         if (file->f_mode & FMODE_READ) {
2285                 iter->pg = ftrace_pages_start;
2286
2287                 ret = seq_open(file, &show_ftrace_seq_ops);
2288                 if (!ret) {
2289                         struct seq_file *m = file->private_data;
2290                         m->private = iter;
2291                 } else {
2292                         /* Failed */
2293                         free_ftrace_hash(iter->hash);
2294                         trace_parser_put(&iter->parser);
2295                         kfree(iter);
2296                 }
2297         } else
2298                 file->private_data = iter;
2299         mutex_unlock(&ftrace_regex_lock);
2300
2301         return ret;
2302 }
2303
2304 static int
2305 ftrace_filter_open(struct inode *inode, struct file *file)
2306 {
2307         return ftrace_regex_open(&global_ops, FTRACE_ITER_FILTER,
2308                                  inode, file);
2309 }
2310
2311 static int
2312 ftrace_notrace_open(struct inode *inode, struct file *file)
2313 {
2314         return ftrace_regex_open(&global_ops, FTRACE_ITER_NOTRACE,
2315                                  inode, file);
2316 }
2317
2318 static loff_t
2319 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
2320 {
2321         loff_t ret;
2322
2323         if (file->f_mode & FMODE_READ)
2324                 ret = seq_lseek(file, offset, origin);
2325         else
2326                 file->f_pos = ret = 1;
2327
2328         return ret;
2329 }
2330
2331 static int ftrace_match(char *str, char *regex, int len, int type)
2332 {
2333         int matched = 0;
2334         int slen;
2335
2336         switch (type) {
2337         case MATCH_FULL:
2338                 if (strcmp(str, regex) == 0)
2339                         matched = 1;
2340                 break;
2341         case MATCH_FRONT_ONLY:
2342                 if (strncmp(str, regex, len) == 0)
2343                         matched = 1;
2344                 break;
2345         case MATCH_MIDDLE_ONLY:
2346                 if (strstr(str, regex))
2347                         matched = 1;
2348                 break;
2349         case MATCH_END_ONLY:
2350                 slen = strlen(str);
2351                 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
2352                         matched = 1;
2353                 break;
2354         }
2355
2356         return matched;
2357 }
2358
2359 static int
2360 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
2361 {
2362         struct ftrace_func_entry *entry;
2363         int ret = 0;
2364
2365         entry = ftrace_lookup_ip(hash, rec->ip);
2366         if (not) {
2367                 /* Do nothing if it doesn't exist */
2368                 if (!entry)
2369                         return 0;
2370
2371                 free_hash_entry(hash, entry);
2372         } else {
2373                 /* Do nothing if it exists */
2374                 if (entry)
2375                         return 0;
2376
2377                 ret = add_hash_entry(hash, rec->ip);
2378         }
2379         return ret;
2380 }
2381
2382 static int
2383 ftrace_match_record(struct dyn_ftrace *rec, char *mod,
2384                     char *regex, int len, int type)
2385 {
2386         char str[KSYM_SYMBOL_LEN];
2387         char *modname;
2388
2389         kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
2390
2391         if (mod) {
2392                 /* module lookup requires matching the module */
2393                 if (!modname || strcmp(modname, mod))
2394                         return 0;
2395
2396                 /* blank search means to match all funcs in the mod */
2397                 if (!len)
2398                         return 1;
2399         }
2400
2401         return ftrace_match(str, regex, len, type);
2402 }
2403
2404 static int
2405 match_records(struct ftrace_hash *hash, char *buff,
2406               int len, char *mod, int not)
2407 {
2408         unsigned search_len = 0;
2409         struct ftrace_page *pg;
2410         struct dyn_ftrace *rec;
2411         int type = MATCH_FULL;
2412         char *search = buff;
2413         int found = 0;
2414         int ret;
2415
2416         if (len) {
2417                 type = filter_parse_regex(buff, len, &search, &not);
2418                 search_len = strlen(search);
2419         }
2420
2421         mutex_lock(&ftrace_lock);
2422
2423         if (unlikely(ftrace_disabled))
2424                 goto out_unlock;
2425
2426         do_for_each_ftrace_rec(pg, rec) {
2427
2428                 if (ftrace_match_record(rec, mod, search, search_len, type)) {
2429                         ret = enter_record(hash, rec, not);
2430                         if (ret < 0) {
2431                                 found = ret;
2432                                 goto out_unlock;
2433                         }
2434                         found = 1;
2435                 }
2436         } while_for_each_ftrace_rec();
2437  out_unlock:
2438         mutex_unlock(&ftrace_lock);
2439
2440         return found;
2441 }
2442
2443 static int
2444 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
2445 {
2446         return match_records(hash, buff, len, NULL, 0);
2447 }
2448
2449 static int
2450 ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
2451 {
2452         int not = 0;
2453
2454         /* blank or '*' mean the same */
2455         if (strcmp(buff, "*") == 0)
2456                 buff[0] = 0;
2457
2458         /* handle the case of 'dont filter this module' */
2459         if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
2460                 buff[0] = 0;
2461                 not = 1;
2462         }
2463
2464         return match_records(hash, buff, strlen(buff), mod, not);
2465 }
2466
2467 /*
2468  * We register the module command as a template to show others how
2469  * to register the a command as well.
2470  */
2471
2472 static int
2473 ftrace_mod_callback(struct ftrace_hash *hash,
2474                     char *func, char *cmd, char *param, int enable)
2475 {
2476         char *mod;
2477         int ret = -EINVAL;
2478
2479         /*
2480          * cmd == 'mod' because we only registered this func
2481          * for the 'mod' ftrace_func_command.
2482          * But if you register one func with multiple commands,
2483          * you can tell which command was used by the cmd
2484          * parameter.
2485          */
2486
2487         /* we must have a module name */
2488         if (!param)
2489                 return ret;
2490
2491         mod = strsep(&param, ":");
2492         if (!strlen(mod))
2493                 return ret;
2494
2495         ret = ftrace_match_module_records(hash, func, mod);
2496         if (!ret)
2497                 ret = -EINVAL;
2498         if (ret < 0)
2499                 return ret;
2500
2501         return 0;
2502 }
2503
2504 static struct ftrace_func_command ftrace_mod_cmd = {
2505         .name                   = "mod",
2506         .func                   = ftrace_mod_callback,
2507 };
2508
2509 static int __init ftrace_mod_cmd_init(void)
2510 {
2511         return register_ftrace_command(&ftrace_mod_cmd);
2512 }
2513 device_initcall(ftrace_mod_cmd_init);
2514
2515 static void
2516 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
2517 {
2518         struct ftrace_func_probe *entry;
2519         struct hlist_head *hhd;
2520         struct hlist_node *n;
2521         unsigned long key;
2522
2523         key = hash_long(ip, FTRACE_HASH_BITS);
2524
2525         hhd = &ftrace_func_hash[key];
2526
2527         if (hlist_empty(hhd))
2528                 return;
2529
2530         /*
2531          * Disable preemption for these calls to prevent a RCU grace
2532          * period. This syncs the hash iteration and freeing of items
2533          * on the hash. rcu_read_lock is too dangerous here.
2534          */
2535         preempt_disable_notrace();
2536         hlist_for_each_entry_rcu(entry, n, hhd, node) {
2537                 if (entry->ip == ip)
2538                         entry->ops->func(ip, parent_ip, &entry->data);
2539         }
2540         preempt_enable_notrace();
2541 }
2542
2543 static struct ftrace_ops trace_probe_ops __read_mostly =
2544 {
2545         .func           = function_trace_probe_call,
2546 };
2547
2548 static int ftrace_probe_registered;
2549
2550 static void __enable_ftrace_function_probe(void)
2551 {
2552         int ret;
2553         int i;
2554
2555         if (ftrace_probe_registered)
2556                 return;
2557
2558         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2559                 struct hlist_head *hhd = &ftrace_func_hash[i];
2560                 if (hhd->first)
2561                         break;
2562         }
2563         /* Nothing registered? */
2564         if (i == FTRACE_FUNC_HASHSIZE)
2565                 return;
2566
2567         ret = __register_ftrace_function(&trace_probe_ops);
2568         if (!ret)
2569                 ret = ftrace_startup(&trace_probe_ops, 0);
2570
2571         ftrace_probe_registered = 1;
2572 }
2573
2574 static void __disable_ftrace_function_probe(void)
2575 {
2576         int ret;
2577         int i;
2578
2579         if (!ftrace_probe_registered)
2580                 return;
2581
2582         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2583                 struct hlist_head *hhd = &ftrace_func_hash[i];
2584                 if (hhd->first)
2585                         return;
2586         }
2587
2588         /* no more funcs left */
2589         ret = __unregister_ftrace_function(&trace_probe_ops);
2590         if (!ret)
2591                 ftrace_shutdown(&trace_probe_ops, 0);
2592
2593         ftrace_probe_registered = 0;
2594 }
2595
2596
2597 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
2598 {
2599         struct ftrace_func_probe *entry =
2600                 container_of(rhp, struct ftrace_func_probe, rcu);
2601
2602         if (entry->ops->free)
2603                 entry->ops->free(&entry->data);
2604         kfree(entry);
2605 }
2606
2607
2608 int
2609 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2610                               void *data)
2611 {
2612         struct ftrace_func_probe *entry;
2613         struct ftrace_page *pg;
2614         struct dyn_ftrace *rec;
2615         int type, len, not;
2616         unsigned long key;
2617         int count = 0;
2618         char *search;
2619
2620         type = filter_parse_regex(glob, strlen(glob), &search, &not);
2621         len = strlen(search);
2622
2623         /* we do not support '!' for function probes */
2624         if (WARN_ON(not))
2625                 return -EINVAL;
2626
2627         mutex_lock(&ftrace_lock);
2628
2629         if (unlikely(ftrace_disabled))
2630                 goto out_unlock;
2631
2632         do_for_each_ftrace_rec(pg, rec) {
2633
2634                 if (!ftrace_match_record(rec, NULL, search, len, type))
2635                         continue;
2636
2637                 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2638                 if (!entry) {
2639                         /* If we did not process any, then return error */
2640                         if (!count)
2641                                 count = -ENOMEM;
2642                         goto out_unlock;
2643                 }
2644
2645                 count++;
2646
2647                 entry->data = data;
2648
2649                 /*
2650                  * The caller might want to do something special
2651                  * for each function we find. We call the callback
2652                  * to give the caller an opportunity to do so.
2653                  */
2654                 if (ops->callback) {
2655                         if (ops->callback(rec->ip, &entry->data) < 0) {
2656                                 /* caller does not like this func */
2657                                 kfree(entry);
2658                                 continue;
2659                         }
2660                 }
2661
2662                 entry->ops = ops;
2663                 entry->ip = rec->ip;
2664
2665                 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2666                 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2667
2668         } while_for_each_ftrace_rec();
2669         __enable_ftrace_function_probe();
2670
2671  out_unlock:
2672         mutex_unlock(&ftrace_lock);
2673
2674         return count;
2675 }
2676
2677 enum {
2678         PROBE_TEST_FUNC         = 1,
2679         PROBE_TEST_DATA         = 2
2680 };
2681
2682 static void
2683 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2684                                   void *data, int flags)
2685 {
2686         struct ftrace_func_probe *entry;
2687         struct hlist_node *n, *tmp;
2688         char str[KSYM_SYMBOL_LEN];
2689         int type = MATCH_FULL;
2690         int i, len = 0;
2691         char *search;
2692
2693         if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
2694                 glob = NULL;
2695         else if (glob) {
2696                 int not;
2697
2698                 type = filter_parse_regex(glob, strlen(glob), &search, &not);
2699                 len = strlen(search);
2700
2701                 /* we do not support '!' for function probes */
2702                 if (WARN_ON(not))
2703                         return;
2704         }
2705
2706         mutex_lock(&ftrace_lock);
2707         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2708                 struct hlist_head *hhd = &ftrace_func_hash[i];
2709
2710                 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
2711
2712                         /* break up if statements for readability */
2713                         if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2714                                 continue;
2715
2716                         if ((flags & PROBE_TEST_DATA) && entry->data != data)
2717                                 continue;
2718
2719                         /* do this last, since it is the most expensive */
2720                         if (glob) {
2721                                 kallsyms_lookup(entry->ip, NULL, NULL,
2722                                                 NULL, str);
2723                                 if (!ftrace_match(str, glob, len, type))
2724                                         continue;
2725                         }
2726
2727                         hlist_del_rcu(&entry->node);
2728                         call_rcu_sched(&entry->rcu, ftrace_free_entry_rcu);
2729                 }
2730         }
2731         __disable_ftrace_function_probe();
2732         mutex_unlock(&ftrace_lock);
2733 }
2734
2735 void
2736 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2737                                 void *data)
2738 {
2739         __unregister_ftrace_function_probe(glob, ops, data,
2740                                           PROBE_TEST_FUNC | PROBE_TEST_DATA);
2741 }
2742
2743 void
2744 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
2745 {
2746         __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
2747 }
2748
2749 void unregister_ftrace_function_probe_all(char *glob)
2750 {
2751         __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
2752 }
2753
2754 static LIST_HEAD(ftrace_commands);
2755 static DEFINE_MUTEX(ftrace_cmd_mutex);
2756
2757 int register_ftrace_command(struct ftrace_func_command *cmd)
2758 {
2759         struct ftrace_func_command *p;
2760         int ret = 0;
2761
2762         mutex_lock(&ftrace_cmd_mutex);
2763         list_for_each_entry(p, &ftrace_commands, list) {
2764                 if (strcmp(cmd->name, p->name) == 0) {
2765                         ret = -EBUSY;
2766                         goto out_unlock;
2767                 }
2768         }
2769         list_add(&cmd->list, &ftrace_commands);
2770  out_unlock:
2771         mutex_unlock(&ftrace_cmd_mutex);
2772
2773         return ret;
2774 }
2775
2776 int unregister_ftrace_command(struct ftrace_func_command *cmd)
2777 {
2778         struct ftrace_func_command *p, *n;
2779         int ret = -ENODEV;
2780
2781         mutex_lock(&ftrace_cmd_mutex);
2782         list_for_each_entry_safe(p, n, &ftrace_commands, list) {
2783                 if (strcmp(cmd->name, p->name) == 0) {
2784                         ret = 0;
2785                         list_del_init(&p->list);
2786                         goto out_unlock;
2787                 }
2788         }
2789  out_unlock:
2790         mutex_unlock(&ftrace_cmd_mutex);
2791
2792         return ret;
2793 }
2794
2795 static int ftrace_process_regex(struct ftrace_hash *hash,
2796                                 char *buff, int len, int enable)
2797 {
2798         char *func, *command, *next = buff;
2799         struct ftrace_func_command *p;
2800         int ret = -EINVAL;
2801
2802         func = strsep(&next, ":");
2803
2804         if (!next) {
2805                 ret = ftrace_match_records(hash, func, len);
2806                 if (!ret)
2807                         ret = -EINVAL;
2808                 if (ret < 0)
2809                         return ret;
2810                 return 0;
2811         }
2812
2813         /* command found */
2814
2815         command = strsep(&next, ":");
2816
2817         mutex_lock(&ftrace_cmd_mutex);
2818         list_for_each_entry(p, &ftrace_commands, list) {
2819                 if (strcmp(p->name, command) == 0) {
2820                         ret = p->func(hash, func, command, next, enable);
2821                         goto out_unlock;
2822                 }
2823         }
2824  out_unlock:
2825         mutex_unlock(&ftrace_cmd_mutex);
2826
2827         return ret;
2828 }
2829
2830 static ssize_t
2831 ftrace_regex_write(struct file *file, const char __user *ubuf,
2832                    size_t cnt, loff_t *ppos, int enable)
2833 {
2834         struct ftrace_iterator *iter;
2835         struct trace_parser *parser;
2836         ssize_t ret, read;
2837
2838         if (!cnt)
2839                 return 0;
2840
2841         mutex_lock(&ftrace_regex_lock);
2842
2843         ret = -ENODEV;
2844         if (unlikely(ftrace_disabled))
2845                 goto out_unlock;
2846
2847         if (file->f_mode & FMODE_READ) {
2848                 struct seq_file *m = file->private_data;
2849                 iter = m->private;
2850         } else
2851                 iter = file->private_data;
2852
2853         parser = &iter->parser;
2854         read = trace_get_user(parser, ubuf, cnt, ppos);
2855
2856         if (read >= 0 && trace_parser_loaded(parser) &&
2857             !trace_parser_cont(parser)) {
2858                 ret = ftrace_process_regex(iter->hash, parser->buffer,
2859                                            parser->idx, enable);
2860                 trace_parser_clear(parser);
2861                 if (ret)
2862                         goto out_unlock;
2863         }
2864
2865         ret = read;
2866 out_unlock:
2867         mutex_unlock(&ftrace_regex_lock);
2868
2869         return ret;
2870 }
2871
2872 static ssize_t
2873 ftrace_filter_write(struct file *file, const char __user *ubuf,
2874                     size_t cnt, loff_t *ppos)
2875 {
2876         return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
2877 }
2878
2879 static ssize_t
2880 ftrace_notrace_write(struct file *file, const char __user *ubuf,
2881                      size_t cnt, loff_t *ppos)
2882 {
2883         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
2884 }
2885
2886 static int
2887 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
2888                  int reset, int enable)
2889 {
2890         struct ftrace_hash **orig_hash;
2891         struct ftrace_hash *hash;
2892         int ret;
2893
2894         /* All global ops uses the global ops filters */
2895         if (ops->flags & FTRACE_OPS_FL_GLOBAL)
2896                 ops = &global_ops;
2897
2898         if (unlikely(ftrace_disabled))
2899                 return -ENODEV;
2900
2901         if (enable)
2902                 orig_hash = &ops->filter_hash;
2903         else
2904                 orig_hash = &ops->notrace_hash;
2905
2906         hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
2907         if (!hash)
2908                 return -ENOMEM;
2909
2910         mutex_lock(&ftrace_regex_lock);
2911         if (reset)
2912                 ftrace_filter_reset(hash);
2913         if (buf)
2914                 ftrace_match_records(hash, buf, len);
2915
2916         mutex_lock(&ftrace_lock);
2917         ret = ftrace_hash_move(ops, enable, orig_hash, hash);
2918         if (!ret && ops->flags & FTRACE_OPS_FL_ENABLED
2919             && ftrace_enabled)
2920                 ftrace_run_update_code(FTRACE_UPDATE_CALLS);
2921
2922         mutex_unlock(&ftrace_lock);
2923
2924         mutex_unlock(&ftrace_regex_lock);
2925
2926         free_ftrace_hash(hash);
2927         return ret;
2928 }
2929
2930 /**
2931  * ftrace_set_filter - set a function to filter on in ftrace
2932  * @ops - the ops to set the filter with
2933  * @buf - the string that holds the function filter text.
2934  * @len - the length of the string.
2935  * @reset - non zero to reset all filters before applying this filter.
2936  *
2937  * Filters denote which functions should be enabled when tracing is enabled.
2938  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2939  */
2940 void ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
2941                        int len, int reset)
2942 {
2943         ftrace_set_regex(ops, buf, len, reset, 1);
2944 }
2945 EXPORT_SYMBOL_GPL(ftrace_set_filter);
2946
2947 /**
2948  * ftrace_set_notrace - set a function to not trace in ftrace
2949  * @ops - the ops to set the notrace filter with
2950  * @buf - the string that holds the function notrace text.
2951  * @len - the length of the string.
2952  * @reset - non zero to reset all filters before applying this filter.
2953  *
2954  * Notrace Filters denote which functions should not be enabled when tracing
2955  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2956  * for tracing.
2957  */
2958 void ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
2959                         int len, int reset)
2960 {
2961         ftrace_set_regex(ops, buf, len, reset, 0);
2962 }
2963 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
2964 /**
2965  * ftrace_set_filter - set a function to filter on in ftrace
2966  * @ops - the ops to set the filter with
2967  * @buf - the string that holds the function filter text.
2968  * @len - the length of the string.
2969  * @reset - non zero to reset all filters before applying this filter.
2970  *
2971  * Filters denote which functions should be enabled when tracing is enabled.
2972  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2973  */
2974 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
2975 {
2976         ftrace_set_regex(&global_ops, buf, len, reset, 1);
2977 }
2978 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
2979
2980 /**
2981  * ftrace_set_notrace - set a function to not trace in ftrace
2982  * @ops - the ops to set the notrace filter with
2983  * @buf - the string that holds the function notrace text.
2984  * @len - the length of the string.
2985  * @reset - non zero to reset all filters before applying this filter.
2986  *
2987  * Notrace Filters denote which functions should not be enabled when tracing
2988  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2989  * for tracing.
2990  */
2991 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
2992 {
2993         ftrace_set_regex(&global_ops, buf, len, reset, 0);
2994 }
2995 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
2996
2997 /*
2998  * command line interface to allow users to set filters on boot up.
2999  */
3000 #define FTRACE_FILTER_SIZE              COMMAND_LINE_SIZE
3001 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
3002 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
3003
3004 static int __init set_ftrace_notrace(char *str)
3005 {
3006         strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
3007         return 1;
3008 }
3009 __setup("ftrace_notrace=", set_ftrace_notrace);
3010
3011 static int __init set_ftrace_filter(char *str)
3012 {
3013         strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
3014         return 1;
3015 }
3016 __setup("ftrace_filter=", set_ftrace_filter);
3017
3018 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3019 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
3020 static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
3021
3022 static int __init set_graph_function(char *str)
3023 {
3024         strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
3025         return 1;
3026 }
3027 __setup("ftrace_graph_filter=", set_graph_function);
3028
3029 static void __init set_ftrace_early_graph(char *buf)
3030 {
3031         int ret;
3032         char *func;
3033
3034         while (buf) {
3035                 func = strsep(&buf, ",");
3036                 /* we allow only one expression at a time */
3037                 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3038                                       func);
3039                 if (ret)
3040                         printk(KERN_DEBUG "ftrace: function %s not "
3041                                           "traceable\n", func);
3042         }
3043 }
3044 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3045
3046 static void __init
3047 set_ftrace_early_filter(struct ftrace_ops *ops, char *buf, int enable)
3048 {
3049         char *func;
3050
3051         while (buf) {
3052                 func = strsep(&buf, ",");
3053                 ftrace_set_regex(ops, func, strlen(func), 0, enable);
3054         }
3055 }
3056
3057 static void __init set_ftrace_early_filters(void)
3058 {
3059         if (ftrace_filter_buf[0])
3060                 set_ftrace_early_filter(&global_ops, ftrace_filter_buf, 1);
3061         if (ftrace_notrace_buf[0])
3062                 set_ftrace_early_filter(&global_ops, ftrace_notrace_buf, 0);
3063 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3064         if (ftrace_graph_buf[0])
3065                 set_ftrace_early_graph(ftrace_graph_buf);
3066 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3067 }
3068
3069 static int
3070 ftrace_regex_release(struct inode *inode, struct file *file)
3071 {
3072         struct seq_file *m = (struct seq_file *)file->private_data;
3073         struct ftrace_iterator *iter;
3074         struct ftrace_hash **orig_hash;
3075         struct trace_parser *parser;
3076         int filter_hash;
3077         int ret;
3078
3079         mutex_lock(&ftrace_regex_lock);
3080         if (file->f_mode & FMODE_READ) {
3081                 iter = m->private;
3082
3083                 seq_release(inode, file);
3084         } else
3085                 iter = file->private_data;
3086
3087         parser = &iter->parser;
3088         if (trace_parser_loaded(parser)) {
3089                 parser->buffer[parser->idx] = 0;
3090                 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
3091         }
3092
3093         trace_parser_put(parser);
3094
3095         if (file->f_mode & FMODE_WRITE) {
3096                 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
3097
3098                 if (filter_hash)
3099                         orig_hash = &iter->ops->filter_hash;
3100                 else
3101                         orig_hash = &iter->ops->notrace_hash;
3102
3103                 mutex_lock(&ftrace_lock);
3104                 ret = ftrace_hash_move(iter->ops, filter_hash,
3105                                        orig_hash, iter->hash);
3106                 if (!ret && (iter->ops->flags & FTRACE_OPS_FL_ENABLED)
3107                     && ftrace_enabled)
3108                         ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3109
3110                 mutex_unlock(&ftrace_lock);
3111         }
3112         free_ftrace_hash(iter->hash);
3113         kfree(iter);
3114
3115         mutex_unlock(&ftrace_regex_lock);
3116         return 0;
3117 }
3118
3119 static const struct file_operations ftrace_avail_fops = {
3120         .open = ftrace_avail_open,
3121         .read = seq_read,
3122         .llseek = seq_lseek,
3123         .release = seq_release_private,
3124 };
3125
3126 static const struct file_operations ftrace_enabled_fops = {
3127         .open = ftrace_enabled_open,
3128         .read = seq_read,
3129         .llseek = seq_lseek,
3130         .release = seq_release_private,
3131 };
3132
3133 static const struct file_operations ftrace_filter_fops = {
3134         .open = ftrace_filter_open,
3135         .read = seq_read,
3136         .write = ftrace_filter_write,
3137         .llseek = ftrace_regex_lseek,
3138         .release = ftrace_regex_release,
3139 };
3140
3141 static const struct file_operations ftrace_notrace_fops = {
3142         .open = ftrace_notrace_open,
3143         .read = seq_read,
3144         .write = ftrace_notrace_write,
3145         .llseek = ftrace_regex_lseek,
3146         .release = ftrace_regex_release,
3147 };
3148
3149 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3150
3151 static DEFINE_MUTEX(graph_lock);
3152
3153 int ftrace_graph_count;
3154 int ftrace_graph_filter_enabled;
3155 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
3156
3157 static void *
3158 __g_next(struct seq_file *m, loff_t *pos)
3159 {
3160         if (*pos >= ftrace_graph_count)
3161                 return NULL;
3162         return &ftrace_graph_funcs[*pos];
3163 }
3164
3165 static void *
3166 g_next(struct seq_file *m, void *v, loff_t *pos)
3167 {
3168         (*pos)++;
3169         return __g_next(m, pos);
3170 }
3171
3172 static void *g_start(struct seq_file *m, loff_t *pos)
3173 {
3174         mutex_lock(&graph_lock);
3175
3176         /* Nothing, tell g_show to print all functions are enabled */
3177         if (!ftrace_graph_filter_enabled && !*pos)
3178                 return (void *)1;
3179
3180         return __g_next(m, pos);
3181 }
3182
3183 static void g_stop(struct seq_file *m, void *p)
3184 {
3185         mutex_unlock(&graph_lock);
3186 }
3187
3188 static int g_show(struct seq_file *m, void *v)
3189 {
3190         unsigned long *ptr = v;
3191
3192         if (!ptr)
3193                 return 0;
3194
3195         if (ptr == (unsigned long *)1) {
3196                 seq_printf(m, "#### all functions enabled ####\n");
3197                 return 0;
3198         }
3199
3200         seq_printf(m, "%ps\n", (void *)*ptr);
3201
3202         return 0;
3203 }
3204
3205 static const struct seq_operations ftrace_graph_seq_ops = {
3206         .start = g_start,
3207         .next = g_next,
3208         .stop = g_stop,
3209         .show = g_show,
3210 };
3211
3212 static int
3213 ftrace_graph_open(struct inode *inode, struct file *file)
3214 {
3215         int ret = 0;
3216
3217         if (unlikely(ftrace_disabled))
3218                 return -ENODEV;
3219
3220         mutex_lock(&graph_lock);
3221         if ((file->f_mode & FMODE_WRITE) &&
3222             (file->f_flags & O_TRUNC)) {
3223                 ftrace_graph_filter_enabled = 0;
3224                 ftrace_graph_count = 0;
3225                 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
3226         }
3227         mutex_unlock(&graph_lock);
3228
3229         if (file->f_mode & FMODE_READ)
3230                 ret = seq_open(file, &ftrace_graph_seq_ops);
3231
3232         return ret;
3233 }
3234
3235 static int
3236 ftrace_graph_release(struct inode *inode, struct file *file)
3237 {
3238         if (file->f_mode & FMODE_READ)
3239                 seq_release(inode, file);
3240         return 0;
3241 }
3242
3243 static int
3244 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
3245 {
3246         struct dyn_ftrace *rec;
3247         struct ftrace_page *pg;
3248         int search_len;
3249         int fail = 1;
3250         int type, not;
3251         char *search;
3252         bool exists;
3253         int i;
3254
3255         /* decode regex */
3256         type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
3257         if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
3258                 return -EBUSY;
3259
3260         search_len = strlen(search);
3261
3262         mutex_lock(&ftrace_lock);
3263
3264         if (unlikely(ftrace_disabled)) {
3265                 mutex_unlock(&ftrace_lock);
3266                 return -ENODEV;
3267         }
3268
3269         do_for_each_ftrace_rec(pg, rec) {
3270
3271                 if (rec->flags & FTRACE_FL_FREE)
3272                         continue;
3273
3274                 if (ftrace_match_record(rec, NULL, search, search_len, type)) {
3275                         /* if it is in the array */
3276                         exists = false;
3277                         for (i = 0; i < *idx; i++) {
3278                                 if (array[i] == rec->ip) {
3279                                         exists = true;
3280                                         break;
3281                                 }
3282                         }
3283
3284                         if (!not) {
3285                                 fail = 0;
3286                                 if (!exists) {
3287                                         array[(*idx)++] = rec->ip;
3288                                         if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
3289                                                 goto out;
3290                                 }
3291                         } else {
3292                                 if (exists) {
3293                                         array[i] = array[--(*idx)];
3294                                         array[*idx] = 0;
3295                                         fail = 0;
3296                                 }
3297                         }
3298                 }
3299         } while_for_each_ftrace_rec();
3300 out:
3301         mutex_unlock(&ftrace_lock);
3302
3303         if (fail)
3304                 return -EINVAL;
3305
3306         ftrace_graph_filter_enabled = 1;
3307         return 0;
3308 }
3309
3310 static ssize_t
3311 ftrace_graph_write(struct file *file, const char __user *ubuf,
3312                    size_t cnt, loff_t *ppos)
3313 {
3314         struct trace_parser parser;
3315         ssize_t read, ret;
3316
3317         if (!cnt)
3318                 return 0;
3319
3320         mutex_lock(&graph_lock);
3321
3322         if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
3323                 ret = -ENOMEM;
3324                 goto out_unlock;
3325         }
3326
3327         read = trace_get_user(&parser, ubuf, cnt, ppos);
3328
3329         if (read >= 0 && trace_parser_loaded((&parser))) {
3330                 parser.buffer[parser.idx] = 0;
3331
3332                 /* we allow only one expression at a time */
3333                 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3334                                         parser.buffer);
3335                 if (ret)
3336                         goto out_free;
3337         }
3338
3339         ret = read;
3340
3341 out_free:
3342         trace_parser_put(&parser);
3343 out_unlock:
3344         mutex_unlock(&graph_lock);
3345
3346         return ret;
3347 }
3348
3349 static const struct file_operations ftrace_graph_fops = {
3350         .open           = ftrace_graph_open,
3351         .read           = seq_read,
3352         .write          = ftrace_graph_write,
3353         .release        = ftrace_graph_release,
3354         .llseek         = seq_lseek,
3355 };
3356 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3357
3358 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
3359 {
3360
3361         trace_create_file("available_filter_functions", 0444,
3362                         d_tracer, NULL, &ftrace_avail_fops);
3363
3364         trace_create_file("enabled_functions", 0444,
3365                         d_tracer, NULL, &ftrace_enabled_fops);
3366
3367         trace_create_file("set_ftrace_filter", 0644, d_tracer,
3368                         NULL, &ftrace_filter_fops);
3369
3370         trace_create_file("set_ftrace_notrace", 0644, d_tracer,
3371                                     NULL, &ftrace_notrace_fops);
3372
3373 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3374         trace_create_file("set_graph_function", 0444, d_tracer,
3375                                     NULL,
3376                                     &ftrace_graph_fops);
3377 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3378
3379         return 0;
3380 }
3381
3382 static int ftrace_process_locs(struct module *mod,
3383                                unsigned long *start,
3384                                unsigned long *end)
3385 {
3386         unsigned long *p;
3387         unsigned long addr;
3388         unsigned long flags = 0; /* Shut up gcc */
3389
3390         mutex_lock(&ftrace_lock);
3391         p = start;
3392         while (p < end) {
3393                 addr = ftrace_call_adjust(*p++);
3394                 /*
3395                  * Some architecture linkers will pad between
3396                  * the different mcount_loc sections of different
3397                  * object files to satisfy alignments.
3398                  * Skip any NULL pointers.
3399                  */
3400                 if (!addr)
3401                         continue;
3402                 ftrace_record_ip(addr);
3403         }
3404
3405         /*
3406          * We only need to disable interrupts on start up
3407          * because we are modifying code that an interrupt
3408          * may execute, and the modification is not atomic.
3409          * But for modules, nothing runs the code we modify
3410          * until we are finished with it, and there's no
3411          * reason to cause large interrupt latencies while we do it.
3412          */
3413         if (!mod)
3414                 local_irq_save(flags);
3415         ftrace_update_code(mod);
3416         if (!mod)
3417                 local_irq_restore(flags);
3418         mutex_unlock(&ftrace_lock);
3419
3420         return 0;
3421 }
3422
3423 #ifdef CONFIG_MODULES
3424 void ftrace_release_mod(struct module *mod)
3425 {
3426         struct dyn_ftrace *rec;
3427         struct ftrace_page *pg;
3428
3429         mutex_lock(&ftrace_lock);
3430
3431         if (ftrace_disabled)
3432                 goto out_unlock;
3433
3434         do_for_each_ftrace_rec(pg, rec) {
3435                 if (within_module_core(rec->ip, mod)) {
3436                         /*
3437                          * rec->ip is changed in ftrace_free_rec()
3438                          * It should not between s and e if record was freed.
3439                          */
3440                         FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
3441                         ftrace_free_rec(rec);
3442                 }
3443         } while_for_each_ftrace_rec();
3444  out_unlock:
3445         mutex_unlock(&ftrace_lock);
3446 }
3447
3448 static void ftrace_init_module(struct module *mod,
3449                                unsigned long *start, unsigned long *end)
3450 {
3451         if (ftrace_disabled || start == end)
3452                 return;
3453         ftrace_process_locs(mod, start, end);
3454 }
3455
3456 static int ftrace_module_notify_enter(struct notifier_block *self,
3457                                       unsigned long val, void *data)
3458 {
3459         struct module *mod = data;
3460
3461         if (val == MODULE_STATE_COMING)
3462                 ftrace_init_module(mod, mod->ftrace_callsites,
3463                                    mod->ftrace_callsites +
3464                                    mod->num_ftrace_callsites);
3465         return 0;
3466 }
3467
3468 static int ftrace_module_notify_exit(struct notifier_block *self,
3469                                      unsigned long val, void *data)
3470 {
3471         struct module *mod = data;
3472
3473         if (val == MODULE_STATE_GOING)
3474                 ftrace_release_mod(mod);
3475
3476         return 0;
3477 }
3478 #else
3479 static int ftrace_module_notify_enter(struct notifier_block *self,
3480                                       unsigned long val, void *data)
3481 {
3482         return 0;
3483 }
3484 static int ftrace_module_notify_exit(struct notifier_block *self,
3485                                      unsigned long val, void *data)
3486 {
3487         return 0;
3488 }
3489 #endif /* CONFIG_MODULES */
3490
3491 struct notifier_block ftrace_module_enter_nb = {
3492         .notifier_call = ftrace_module_notify_enter,
3493         .priority = INT_MAX,    /* Run before anything that can use kprobes */
3494 };
3495
3496 struct notifier_block ftrace_module_exit_nb = {
3497         .notifier_call = ftrace_module_notify_exit,
3498         .priority = INT_MIN,    /* Run after anything that can remove kprobes */
3499 };
3500
3501 extern unsigned long __start_mcount_loc[];
3502 extern unsigned long __stop_mcount_loc[];
3503
3504 void __init ftrace_init(void)
3505 {
3506         unsigned long count, addr, flags;
3507         int ret;
3508
3509         /* Keep the ftrace pointer to the stub */
3510         addr = (unsigned long)ftrace_stub;
3511
3512         local_irq_save(flags);
3513         ftrace_dyn_arch_init(&addr);
3514         local_irq_restore(flags);
3515
3516         /* ftrace_dyn_arch_init places the return code in addr */
3517         if (addr)
3518                 goto failed;
3519
3520         count = __stop_mcount_loc - __start_mcount_loc;
3521
3522         ret = ftrace_dyn_table_alloc(count);
3523         if (ret)
3524                 goto failed;
3525
3526         last_ftrace_enabled = ftrace_enabled = 1;
3527
3528         ret = ftrace_process_locs(NULL,
3529                                   __start_mcount_loc,
3530                                   __stop_mcount_loc);
3531
3532         ret = register_module_notifier(&ftrace_module_enter_nb);
3533         if (ret)
3534                 pr_warning("Failed to register trace ftrace module enter notifier\n");
3535
3536         ret = register_module_notifier(&ftrace_module_exit_nb);
3537         if (ret)
3538                 pr_warning("Failed to register trace ftrace module exit notifier\n");
3539
3540         set_ftrace_early_filters();
3541
3542         return;
3543  failed:
3544         ftrace_disabled = 1;
3545 }
3546
3547 #else
3548
3549 static struct ftrace_ops global_ops = {
3550         .func                   = ftrace_stub,
3551 };
3552
3553 static int __init ftrace_nodyn_init(void)
3554 {
3555         ftrace_enabled = 1;
3556         return 0;
3557 }
3558 device_initcall(ftrace_nodyn_init);
3559
3560 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
3561 static inline void ftrace_startup_enable(int command) { }
3562 /* Keep as macros so we do not need to define the commands */
3563 # define ftrace_startup(ops, command)                   \
3564         ({                                              \
3565                 (ops)->flags |= FTRACE_OPS_FL_ENABLED;  \
3566                 0;                                      \
3567         })
3568 # define ftrace_shutdown(ops, command)  do { } while (0)
3569 # define ftrace_startup_sysctl()        do { } while (0)
3570 # define ftrace_shutdown_sysctl()       do { } while (0)
3571
3572 static inline int
3573 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
3574 {
3575         return 1;
3576 }
3577
3578 #endif /* CONFIG_DYNAMIC_FTRACE */
3579
3580 static void
3581 ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
3582 {
3583         struct ftrace_ops *op;
3584
3585         if (unlikely(trace_recursion_test(TRACE_INTERNAL_BIT)))
3586                 return;
3587
3588         trace_recursion_set(TRACE_INTERNAL_BIT);
3589         /*
3590          * Some of the ops may be dynamically allocated,
3591          * they must be freed after a synchronize_sched().
3592          */
3593         preempt_disable_notrace();
3594         op = rcu_dereference_raw(ftrace_ops_list);
3595         while (op != &ftrace_list_end) {
3596                 if (ftrace_ops_test(op, ip))
3597                         op->func(ip, parent_ip);
3598                 op = rcu_dereference_raw(op->next);
3599         };
3600         preempt_enable_notrace();
3601         trace_recursion_clear(TRACE_INTERNAL_BIT);
3602 }
3603
3604 static void clear_ftrace_swapper(void)
3605 {
3606         struct task_struct *p;
3607         int cpu;
3608
3609         get_online_cpus();
3610         for_each_online_cpu(cpu) {
3611                 p = idle_task(cpu);
3612                 clear_tsk_trace_trace(p);
3613         }
3614         put_online_cpus();
3615 }
3616
3617 static void set_ftrace_swapper(void)
3618 {
3619         struct task_struct *p;
3620         int cpu;
3621
3622         get_online_cpus();
3623         for_each_online_cpu(cpu) {
3624                 p = idle_task(cpu);
3625                 set_tsk_trace_trace(p);
3626         }
3627         put_online_cpus();
3628 }
3629
3630 static void clear_ftrace_pid(struct pid *pid)
3631 {
3632         struct task_struct *p;
3633
3634         rcu_read_lock();
3635         do_each_pid_task(pid, PIDTYPE_PID, p) {
3636                 clear_tsk_trace_trace(p);
3637         } while_each_pid_task(pid, PIDTYPE_PID, p);
3638         rcu_read_unlock();
3639
3640         put_pid(pid);
3641 }
3642
3643 static void set_ftrace_pid(struct pid *pid)
3644 {
3645         struct task_struct *p;
3646
3647         rcu_read_lock();
3648         do_each_pid_task(pid, PIDTYPE_PID, p) {
3649                 set_tsk_trace_trace(p);
3650         } while_each_pid_task(pid, PIDTYPE_PID, p);
3651         rcu_read_unlock();
3652 }
3653
3654 static void clear_ftrace_pid_task(struct pid *pid)
3655 {
3656         if (pid == ftrace_swapper_pid)
3657                 clear_ftrace_swapper();
3658         else
3659                 clear_ftrace_pid(pid);
3660 }
3661
3662 static void set_ftrace_pid_task(struct pid *pid)
3663 {
3664         if (pid == ftrace_swapper_pid)
3665                 set_ftrace_swapper();
3666         else
3667                 set_ftrace_pid(pid);
3668 }
3669
3670 static int ftrace_pid_add(int p)
3671 {
3672         struct pid *pid;
3673         struct ftrace_pid *fpid;
3674         int ret = -EINVAL;
3675
3676         mutex_lock(&ftrace_lock);
3677
3678         if (!p)
3679                 pid = ftrace_swapper_pid;
3680         else
3681                 pid = find_get_pid(p);
3682
3683         if (!pid)
3684                 goto out;
3685
3686         ret = 0;
3687
3688         list_for_each_entry(fpid, &ftrace_pids, list)
3689                 if (fpid->pid == pid)
3690                         goto out_put;
3691
3692         ret = -ENOMEM;
3693
3694         fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
3695         if (!fpid)
3696                 goto out_put;
3697
3698         list_add(&fpid->list, &ftrace_pids);
3699         fpid->pid = pid;
3700
3701         set_ftrace_pid_task(pid);
3702
3703         ftrace_update_pid_func();
3704         ftrace_startup_enable(0);
3705
3706         mutex_unlock(&ftrace_lock);
3707         return 0;
3708
3709 out_put:
3710         if (pid != ftrace_swapper_pid)
3711                 put_pid(pid);
3712
3713 out:
3714         mutex_unlock(&ftrace_lock);
3715         return ret;
3716 }
3717
3718 static void ftrace_pid_reset(void)
3719 {
3720         struct ftrace_pid *fpid, *safe;
3721
3722         mutex_lock(&ftrace_lock);
3723         list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
3724                 struct pid *pid = fpid->pid;
3725
3726                 clear_ftrace_pid_task(pid);
3727
3728                 list_del(&fpid->list);
3729                 kfree(fpid);
3730         }
3731
3732         ftrace_update_pid_func();
3733         ftrace_startup_enable(0);
3734
3735         mutex_unlock(&ftrace_lock);
3736 }
3737
3738 static void *fpid_start(struct seq_file *m, loff_t *pos)
3739 {
3740         mutex_lock(&ftrace_lock);
3741
3742         if (list_empty(&ftrace_pids) && (!*pos))
3743                 return (void *) 1;
3744
3745         return seq_list_start(&ftrace_pids, *pos);
3746 }
3747
3748 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
3749 {
3750         if (v == (void *)1)
3751                 return NULL;
3752
3753         return seq_list_next(v, &ftrace_pids, pos);
3754 }
3755
3756 static void fpid_stop(struct seq_file *m, void *p)
3757 {
3758         mutex_unlock(&ftrace_lock);
3759 }
3760
3761 static int fpid_show(struct seq_file *m, void *v)
3762 {
3763         const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
3764
3765         if (v == (void *)1) {
3766                 seq_printf(m, "no pid\n");
3767                 return 0;
3768         }
3769
3770         if (fpid->pid == ftrace_swapper_pid)
3771                 seq_printf(m, "swapper tasks\n");
3772         else
3773                 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
3774
3775         return 0;
3776 }
3777
3778 static const struct seq_operations ftrace_pid_sops = {
3779         .start = fpid_start,
3780         .next = fpid_next,
3781         .stop = fpid_stop,
3782         .show = fpid_show,
3783 };
3784
3785 static int
3786 ftrace_pid_open(struct inode *inode, struct file *file)
3787 {
3788         int ret = 0;
3789
3790         if ((file->f_mode & FMODE_WRITE) &&
3791             (file->f_flags & O_TRUNC))
3792                 ftrace_pid_reset();
3793
3794         if (file->f_mode & FMODE_READ)
3795                 ret = seq_open(file, &ftrace_pid_sops);
3796
3797         return ret;
3798 }
3799
3800 static ssize_t
3801 ftrace_pid_write(struct file *filp, const char __user *ubuf,
3802                    size_t cnt, loff_t *ppos)
3803 {
3804         char buf[64], *tmp;
3805         long val;
3806         int ret;
3807
3808         if (cnt >= sizeof(buf))
3809                 return -EINVAL;
3810
3811         if (copy_from_user(&buf, ubuf, cnt))
3812                 return -EFAULT;
3813
3814         buf[cnt] = 0;
3815
3816         /*
3817          * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
3818          * to clean the filter quietly.
3819          */
3820         tmp = strstrip(buf);
3821         if (strlen(tmp) == 0)
3822                 return 1;
3823
3824         ret = strict_strtol(tmp, 10, &val);
3825         if (ret < 0)
3826                 return ret;
3827
3828         ret = ftrace_pid_add(val);
3829
3830         return ret ? ret : cnt;
3831 }
3832
3833 static int
3834 ftrace_pid_release(struct inode *inode, struct file *file)
3835 {
3836         if (file->f_mode & FMODE_READ)
3837                 seq_release(inode, file);
3838
3839         return 0;
3840 }
3841
3842 static const struct file_operations ftrace_pid_fops = {
3843         .open           = ftrace_pid_open,
3844         .write          = ftrace_pid_write,
3845         .read           = seq_read,
3846         .llseek         = seq_lseek,
3847         .release        = ftrace_pid_release,
3848 };
3849
3850 static __init int ftrace_init_debugfs(void)
3851 {
3852         struct dentry *d_tracer;
3853
3854         d_tracer = tracing_init_dentry();
3855         if (!d_tracer)
3856                 return 0;
3857
3858         ftrace_init_dyn_debugfs(d_tracer);
3859
3860         trace_create_file("set_ftrace_pid", 0644, d_tracer,
3861                             NULL, &ftrace_pid_fops);
3862
3863         ftrace_profile_debugfs(d_tracer);
3864
3865         return 0;
3866 }
3867 fs_initcall(ftrace_init_debugfs);
3868
3869 /**
3870  * ftrace_kill - kill ftrace
3871  *
3872  * This function should be used by panic code. It stops ftrace
3873  * but in a not so nice way. If you need to simply kill ftrace
3874  * from a non-atomic section, use ftrace_kill.
3875  */
3876 void ftrace_kill(void)
3877 {
3878         ftrace_disabled = 1;
3879         ftrace_enabled = 0;
3880         clear_ftrace_function();
3881 }
3882
3883 /**
3884  * Test if ftrace is dead or not.
3885  */
3886 int ftrace_is_dead(void)
3887 {
3888         return ftrace_disabled;
3889 }
3890
3891 /**
3892  * register_ftrace_function - register a function for profiling
3893  * @ops - ops structure that holds the function for profiling.
3894  *
3895  * Register a function to be called by all functions in the
3896  * kernel.
3897  *
3898  * Note: @ops->func and all the functions it calls must be labeled
3899  *       with "notrace", otherwise it will go into a
3900  *       recursive loop.
3901  */
3902 int register_ftrace_function(struct ftrace_ops *ops)
3903 {
3904         int ret = -1;
3905
3906         mutex_lock(&ftrace_lock);
3907
3908         if (unlikely(ftrace_disabled))
3909                 goto out_unlock;
3910
3911         ret = __register_ftrace_function(ops);
3912         if (!ret)
3913                 ret = ftrace_startup(ops, 0);
3914
3915
3916  out_unlock:
3917         mutex_unlock(&ftrace_lock);
3918         return ret;
3919 }
3920 EXPORT_SYMBOL_GPL(register_ftrace_function);
3921
3922 /**
3923  * unregister_ftrace_function - unregister a function for profiling.
3924  * @ops - ops structure that holds the function to unregister
3925  *
3926  * Unregister a function that was added to be called by ftrace profiling.
3927  */
3928 int unregister_ftrace_function(struct ftrace_ops *ops)
3929 {
3930         int ret;
3931
3932         mutex_lock(&ftrace_lock);
3933         ret = __unregister_ftrace_function(ops);
3934         if (!ret)
3935                 ftrace_shutdown(ops, 0);
3936         mutex_unlock(&ftrace_lock);
3937
3938         return ret;
3939 }
3940 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
3941
3942 int
3943 ftrace_enable_sysctl(struct ctl_table *table, int write,
3944                      void __user *buffer, size_t *lenp,
3945                      loff_t *ppos)
3946 {
3947         int ret = -ENODEV;
3948
3949         mutex_lock(&ftrace_lock);
3950
3951         if (unlikely(ftrace_disabled))
3952                 goto out;
3953
3954         ret = proc_dointvec(table, write, buffer, lenp, ppos);
3955
3956         if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
3957                 goto out;
3958
3959         last_ftrace_enabled = !!ftrace_enabled;
3960
3961         if (ftrace_enabled) {
3962
3963                 ftrace_startup_sysctl();
3964
3965                 /* we are starting ftrace again */
3966                 if (ftrace_ops_list != &ftrace_list_end)
3967                         update_ftrace_function();
3968
3969         } else {
3970                 /* stopping ftrace calls (just send to ftrace_stub) */
3971                 ftrace_trace_function = ftrace_stub;
3972
3973                 ftrace_shutdown_sysctl();
3974         }
3975
3976  out:
3977         mutex_unlock(&ftrace_lock);
3978         return ret;
3979 }
3980
3981 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3982
3983 static int ftrace_graph_active;
3984 static struct notifier_block ftrace_suspend_notifier;
3985
3986 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
3987 {
3988         return 0;
3989 }
3990
3991 /* The callbacks that hook a function */
3992 trace_func_graph_ret_t ftrace_graph_return =
3993                         (trace_func_graph_ret_t)ftrace_stub;
3994 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
3995
3996 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3997 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
3998 {
3999         int i;
4000         int ret = 0;
4001         unsigned long flags;
4002         int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
4003         struct task_struct *g, *t;
4004
4005         for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
4006                 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
4007                                         * sizeof(struct ftrace_ret_stack),
4008                                         GFP_KERNEL);
4009                 if (!ret_stack_list[i]) {
4010                         start = 0;
4011                         end = i;
4012                         ret = -ENOMEM;
4013                         goto free;
4014                 }
4015         }
4016
4017         read_lock_irqsave(&tasklist_lock, flags);
4018         do_each_thread(g, t) {
4019                 if (start == end) {
4020                         ret = -EAGAIN;
4021                         goto unlock;
4022                 }
4023
4024                 if (t->ret_stack == NULL) {
4025                         atomic_set(&t->tracing_graph_pause, 0);
4026                         atomic_set(&t->trace_overrun, 0);
4027                         t->curr_ret_stack = -1;
4028                         /* Make sure the tasks see the -1 first: */
4029                         smp_wmb();
4030                         t->ret_stack = ret_stack_list[start++];
4031                 }
4032         } while_each_thread(g, t);
4033
4034 unlock:
4035         read_unlock_irqrestore(&tasklist_lock, flags);
4036 free:
4037         for (i = start; i < end; i++)
4038                 kfree(ret_stack_list[i]);
4039         return ret;
4040 }
4041
4042 static void
4043 ftrace_graph_probe_sched_switch(void *ignore,
4044                         struct task_struct *prev, struct task_struct *next)
4045 {
4046         unsigned long long timestamp;
4047         int index;
4048
4049         /*
4050          * Does the user want to count the time a function was asleep.
4051          * If so, do not update the time stamps.
4052          */
4053         if (trace_flags & TRACE_ITER_SLEEP_TIME)
4054                 return;
4055
4056         timestamp = trace_clock_local();
4057
4058         prev->ftrace_timestamp = timestamp;
4059
4060         /* only process tasks that we timestamped */
4061         if (!next->ftrace_timestamp)
4062                 return;
4063
4064         /*
4065          * Update all the counters in next to make up for the
4066          * time next was sleeping.
4067          */
4068         timestamp -= next->ftrace_timestamp;
4069
4070         for (index = next->curr_ret_stack; index >= 0; index--)
4071                 next->ret_stack[index].calltime += timestamp;
4072 }
4073
4074 /* Allocate a return stack for each task */
4075 static int start_graph_tracing(void)
4076 {
4077         struct ftrace_ret_stack **ret_stack_list;
4078         int ret, cpu;
4079
4080         ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
4081                                 sizeof(struct ftrace_ret_stack *),
4082                                 GFP_KERNEL);
4083
4084         if (!ret_stack_list)
4085                 return -ENOMEM;
4086
4087         /* The cpu_boot init_task->ret_stack will never be freed */
4088         for_each_online_cpu(cpu) {
4089                 if (!idle_task(cpu)->ret_stack)
4090                         ftrace_graph_init_idle_task(idle_task(cpu), cpu);
4091         }
4092
4093         do {
4094                 ret = alloc_retstack_tasklist(ret_stack_list);
4095         } while (ret == -EAGAIN);
4096
4097         if (!ret) {
4098                 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4099                 if (ret)
4100                         pr_info("ftrace_graph: Couldn't activate tracepoint"
4101                                 " probe to kernel_sched_switch\n");
4102         }
4103
4104         kfree(ret_stack_list);
4105         return ret;
4106 }
4107
4108 /*
4109  * Hibernation protection.
4110  * The state of the current task is too much unstable during
4111  * suspend/restore to disk. We want to protect against that.
4112  */
4113 static int
4114 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
4115                                                         void *unused)
4116 {
4117         switch (state) {
4118         case PM_HIBERNATION_PREPARE:
4119                 pause_graph_tracing();
4120                 break;
4121
4122         case PM_POST_HIBERNATION:
4123                 unpause_graph_tracing();
4124                 break;
4125         }
4126         return NOTIFY_DONE;
4127 }
4128
4129 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
4130                         trace_func_graph_ent_t entryfunc)
4131 {
4132         int ret = 0;
4133
4134         mutex_lock(&ftrace_lock);
4135
4136         /* we currently allow only one tracer registered at a time */
4137         if (ftrace_graph_active) {
4138                 ret = -EBUSY;
4139                 goto out;
4140         }
4141
4142         ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
4143         register_pm_notifier(&ftrace_suspend_notifier);
4144
4145         ftrace_graph_active++;
4146         ret = start_graph_tracing();
4147         if (ret) {
4148                 ftrace_graph_active--;
4149                 goto out;
4150         }
4151
4152         ftrace_graph_return = retfunc;
4153         ftrace_graph_entry = entryfunc;
4154
4155         ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
4156
4157 out:
4158         mutex_unlock(&ftrace_lock);
4159         return ret;
4160 }
4161
4162 void unregister_ftrace_graph(void)
4163 {
4164         mutex_lock(&ftrace_lock);
4165
4166         if (unlikely(!ftrace_graph_active))
4167                 goto out;
4168
4169         ftrace_graph_active--;
4170         ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
4171         ftrace_graph_entry = ftrace_graph_entry_stub;
4172         ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET);
4173         unregister_pm_notifier(&ftrace_suspend_notifier);
4174         unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4175
4176  out:
4177         mutex_unlock(&ftrace_lock);
4178 }
4179
4180 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
4181
4182 static void
4183 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
4184 {
4185         atomic_set(&t->tracing_graph_pause, 0);
4186         atomic_set(&t->trace_overrun, 0);
4187         t->ftrace_timestamp = 0;
4188         /* make curr_ret_stack visible before we add the ret_stack */
4189         smp_wmb();
4190         t->ret_stack = ret_stack;
4191 }
4192
4193 /*
4194  * Allocate a return stack for the idle task. May be the first
4195  * time through, or it may be done by CPU hotplug online.
4196  */
4197 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
4198 {
4199         t->curr_ret_stack = -1;
4200         /*
4201          * The idle task has no parent, it either has its own
4202          * stack or no stack at all.
4203          */
4204         if (t->ret_stack)
4205                 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
4206
4207         if (ftrace_graph_active) {
4208                 struct ftrace_ret_stack *ret_stack;
4209
4210                 ret_stack = per_cpu(idle_ret_stack, cpu);
4211                 if (!ret_stack) {
4212                         ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4213                                             * sizeof(struct ftrace_ret_stack),
4214                                             GFP_KERNEL);
4215                         if (!ret_stack)
4216                                 return;
4217                         per_cpu(idle_ret_stack, cpu) = ret_stack;
4218                 }
4219                 graph_init_task(t, ret_stack);
4220         }
4221 }
4222
4223 /* Allocate a return stack for newly created task */
4224 void ftrace_graph_init_task(struct task_struct *t)
4225 {
4226         /* Make sure we do not use the parent ret_stack */
4227         t->ret_stack = NULL;
4228         t->curr_ret_stack = -1;
4229
4230         if (ftrace_graph_active) {
4231                 struct ftrace_ret_stack *ret_stack;
4232
4233                 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4234                                 * sizeof(struct ftrace_ret_stack),
4235                                 GFP_KERNEL);
4236                 if (!ret_stack)
4237                         return;
4238                 graph_init_task(t, ret_stack);
4239         }
4240 }
4241
4242 void ftrace_graph_exit_task(struct task_struct *t)
4243 {
4244         struct ftrace_ret_stack *ret_stack = t->ret_stack;
4245
4246         t->ret_stack = NULL;
4247         /* NULL must become visible to IRQs before we free it: */
4248         barrier();
4249
4250         kfree(ret_stack);
4251 }
4252
4253 void ftrace_graph_stop(void)
4254 {
4255         ftrace_stop();
4256 }
4257 #endif