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