kernel/trace/ftrace.c

   1 /*
   2  * Infrastructure for profiling code inserted by 'gcc -pg'.
   3  *
   4  * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
   5  * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
   6  *
   7  * Originally ported from the -rt patch by:
   8  *   Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
   9  *
  10  * Based on code in the latency_tracer, that is:
  11  *
  12  *  Copyright (C) 2004-2006 Ingo Molnar
  13  *  Copyright (C) 2004 William Lee Irwin III
  14  */
  15
  16 #include <linux/stop_machine.h>
  17 #include <linux/clocksource.h>
  18 #include <linux/kallsyms.h>
  19 #include <linux/seq_file.h>
  20 #include <linux/suspend.h>
  21 #include <linux/debugfs.h>
  22 #include <linux/hardirq.h>
  23 #include <linux/kthread.h>
  24 #include <linux/uaccess.h>
  25 #include <linux/module.h>
  26 #include <linux/ftrace.h>
  27 #include <linux/sysctl.h>
  28 #include <linux/slab.h>
  29 #include <linux/ctype.h>
  30 #include <linux/list.h>
  31 #include <linux/hash.h>
  32 #include <linux/rcupdate.h>
  33
  34 #include <trace/events/sched.h>
  35
  36 #include <asm/setup.h>
  37
  38 #include "trace_output.h"
  39 #include "trace_stat.h"
  40
  41 #define FTRACE_WARN_ON(cond)                    \
  42         ({                                      \
  43                 int ___r = cond;                \
  44                 if (WARN_ON(___r))              \
  45                         ftrace_kill();          \
  46                 ___r;                           \
  47         })
  48
  49 #define FTRACE_WARN_ON_ONCE(cond)               \
  50         ({                                      \
  51                 int ___r = cond;                \
  52                 if (WARN_ON_ONCE(___r))         \
  53                         ftrace_kill();          \
  54                 ___r;                           \
  55         })
  56
  57 /* hash bits for specific function selection */
  58 #define FTRACE_HASH_BITS 7
  59 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
  60 #define FTRACE_HASH_DEFAULT_BITS 10
  61 #define FTRACE_HASH_MAX_BITS 12
  62
  63 /* ftrace_enabled is a method to turn ftrace on or off */
  64 int ftrace_enabled __read_mostly;
  65 static int last_ftrace_enabled;
  66
  67 /* Quick disabling of function tracer. */
  68 int function_trace_stop;
  69
  70 /* List for set_ftrace_pid's pids. */
  71 LIST_HEAD(ftrace_pids);
  72 struct ftrace_pid {
  73         struct list_head list;
  74         struct pid *pid;
  75 };
  76
  77 /*
  78  * ftrace_disabled is set when an anomaly is discovered.
  79  * ftrace_disabled is much stronger than ftrace_enabled.
  80  */
  81 static int ftrace_disabled __read_mostly;
  82
  83 static DEFINE_MUTEX(ftrace_lock);
  84
  85 static struct ftrace_ops ftrace_list_end __read_mostly = {
  86         .func           = ftrace_stub,
  87 };
  88
  89 static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
  90 static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
  91 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
  92 static ftrace_func_t __ftrace_trace_function_delay __read_mostly = ftrace_stub;
  93 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
  94 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
  95 static struct ftrace_ops global_ops;
  96
  97 static void
  98 ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip);
  99
 100 /*
 101  * Traverse the ftrace_global_list, invoking all entries.  The reason that we
 102  * can use rcu_dereference_raw() is that elements removed from this list
 103  * are simply leaked, so there is no need to interact with a grace-period
 104  * mechanism.  The rcu_dereference_raw() calls are needed to handle
 105  * concurrent insertions into the ftrace_global_list.
 106  *
 107  * Silly Alpha and silly pointer-speculation compiler optimizations!
 108  */
 109 static void ftrace_global_list_func(unsigned long ip,
 110                                     unsigned long parent_ip)
 111 {
 112         struct ftrace_ops *op;
 113
 114         if (unlikely(trace_recursion_test(TRACE_GLOBAL_BIT)))
 115                 return;
 116
 117         trace_recursion_set(TRACE_GLOBAL_BIT);
 118         op = rcu_dereference_raw(ftrace_global_list); /*see above*/
 119         while (op != &ftrace_list_end) {
 120                 op->func(ip, parent_ip);
 121                 op = rcu_dereference_raw(op->next); /*see above*/
 122         };
 123         trace_recursion_clear(TRACE_GLOBAL_BIT);
 124 }
 125
 126 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
 127 {
 128         if (!test_tsk_trace_trace(current))
 129                 return;
 130
 131         ftrace_pid_function(ip, parent_ip);
 132 }
 133
 134 static void set_ftrace_pid_function(ftrace_func_t func)
 135 {
 136         /* do not set ftrace_pid_function to itself! */
 137         if (func != ftrace_pid_func)
 138                 ftrace_pid_function = func;
 139 }
 140
 141 /**
 142  * clear_ftrace_function - reset the ftrace function
 143  *
 144  * This NULLs the ftrace function and in essence stops
 145  * tracing.  There may be lag
 146  */
 147 void clear_ftrace_function(void)
 148 {
 149         ftrace_trace_function = ftrace_stub;
 150         __ftrace_trace_function = ftrace_stub;
 151         __ftrace_trace_function_delay = ftrace_stub;
 152         ftrace_pid_function = ftrace_stub;
 153 }
 154
 155 #undef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 156 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 157 /*
 158  * For those archs that do not test ftrace_trace_stop in their
 159  * mcount call site, we need to do it from C.
 160  */
 161 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
 162 {
 163         if (function_trace_stop)
 164                 return;
 165
 166         __ftrace_trace_function(ip, parent_ip);
 167 }
 168 #endif
 169
 170 static void update_global_ops(void)
 171 {
 172         ftrace_func_t func;
 173
 174         /*
 175          * If there's only one function registered, then call that
 176          * function directly. Otherwise, we need to iterate over the
 177          * registered callers.
 178          */
 179         if (ftrace_global_list == &ftrace_list_end ||
 180             ftrace_global_list->next == &ftrace_list_end)
 181                 func = ftrace_global_list->func;
 182         else
 183                 func = ftrace_global_list_func;
 184
 185         /* If we filter on pids, update to use the pid function */
 186         if (!list_empty(&ftrace_pids)) {
 187                 set_ftrace_pid_function(func);
 188                 func = ftrace_pid_func;
 189         }
 190
 191         global_ops.func = func;
 192 }
 193
 194 static void update_ftrace_function(void)
 195 {
 196         ftrace_func_t func;
 197
 198         update_global_ops();
 199
 200         /*
 201          * If we are at the end of the list and this ops is
 202          * not dynamic, then have the mcount trampoline call
 203          * the function directly
 204          */
 205         if (ftrace_ops_list == &ftrace_list_end ||
 206             (ftrace_ops_list->next == &ftrace_list_end &&
 207              !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC)))
 208                 func = ftrace_ops_list->func;
 209         else
 210                 func = ftrace_ops_list_func;
 211
 212 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 213         ftrace_trace_function = func;
 214 #else
 215 #ifdef CONFIG_DYNAMIC_FTRACE
 216         /* do not update till all functions have been modified */
 217         __ftrace_trace_function_delay = func;
 218 #else
 219         __ftrace_trace_function = func;
 220 #endif
 221         ftrace_trace_function = ftrace_test_stop_func;
 222 #endif
 223 }
 224
 225 static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
 226 {
 227         ops->next = *list;
 228         /*
 229          * We are entering ops into the list but another
 230          * CPU might be walking that list. We need to make sure
 231          * the ops->next pointer is valid before another CPU sees
 232          * the ops pointer included into the list.
 233          */
 234         rcu_assign_pointer(*list, ops);
 235 }
 236
 237 static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
 238 {
 239         struct ftrace_ops **p;
 240
 241         /*
 242          * If we are removing the last function, then simply point
 243          * to the ftrace_stub.
 244          */
 245         if (*list == ops && ops->next == &ftrace_list_end) {
 246                 *list = &ftrace_list_end;
 247                 return 0;
 248         }
 249
 250         for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
 251                 if (*p == ops)
 252                         break;
 253
 254         if (*p != ops)
 255                 return -1;
 256
 257         *p = (*p)->next;
 258         return 0;
 259 }
 260
 261 static int __register_ftrace_function(struct ftrace_ops *ops)
 262 {
 263         if (ftrace_disabled)
 264                 return -ENODEV;
 265
 266         if (FTRACE_WARN_ON(ops == &global_ops))
 267                 return -EINVAL;
 268
 269         if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
 270                 return -EBUSY;
 271
 272         if (!core_kernel_data((unsigned long)ops))
 273                 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
 274
 275         if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
 276                 int first = ftrace_global_list == &ftrace_list_end;
 277                 add_ftrace_ops(&ftrace_global_list, ops);
 278                 ops->flags |= FTRACE_OPS_FL_ENABLED;
 279                 if (first)
 280                         add_ftrace_ops(&ftrace_ops_list, &global_ops);
 281         } else
 282                 add_ftrace_ops(&ftrace_ops_list, ops);
 283
 284         if (ftrace_enabled)
 285                 update_ftrace_function();
 286
 287         return 0;
 288 }
 289
 290 static int __unregister_ftrace_function(struct ftrace_ops *ops)
 291 {
 292         int ret;
 293
 294         if (ftrace_disabled)
 295                 return -ENODEV;
 296
 297         if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
 298                 return -EBUSY;
 299
 300         if (FTRACE_WARN_ON(ops == &global_ops))
 301                 return -EINVAL;
 302
 303         if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
 304                 ret = remove_ftrace_ops(&ftrace_global_list, ops);
 305                 if (!ret && ftrace_global_list == &ftrace_list_end)
 306                         ret = remove_ftrace_ops(&ftrace_ops_list, &global_ops);
 307                 if (!ret)
 308                         ops->flags &= ~FTRACE_OPS_FL_ENABLED;
 309         } else
 310                 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
 311
 312         if (ret < 0)
 313                 return ret;
 314
 315         if (ftrace_enabled)
 316                 update_ftrace_function();
 317
 318         /*
 319          * Dynamic ops may be freed, we must make sure that all
 320          * callers are done before leaving this function.
 321          */
 322         if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
 323                 synchronize_sched();
 324
 325         return 0;
 326 }
 327
 328 static void ftrace_update_pid_func(void)
 329 {
 330         /* Only do something if we are tracing something */
 331         if (ftrace_trace_function == ftrace_stub)
 332                 return;
 333
 334         update_ftrace_function();
 335 }
 336
 337 #ifdef CONFIG_FUNCTION_PROFILER
 338 struct ftrace_profile {
 339         struct hlist_node               node;
 340         unsigned long                   ip;
 341         unsigned long                   counter;
 342 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 343         unsigned long long              time;
 344         unsigned long long              time_squared;
 345 #endif
 346 };
 347
 348 struct ftrace_profile_page {
 349         struct ftrace_profile_page      *next;
 350         unsigned long                   index;
 351         struct ftrace_profile           records[];
 352 };
 353
 354 struct ftrace_profile_stat {
 355         atomic_t                        disabled;
 356         struct hlist_head               *hash;
 357         struct ftrace_profile_page      *pages;
 358         struct ftrace_profile_page      *start;
 359         struct tracer_stat              stat;
 360 };
 361
 362 #define PROFILE_RECORDS_SIZE                                            \
 363         (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
 364
 365 #define PROFILES_PER_PAGE                                       \
 366         (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
 367
 368 static int ftrace_profile_bits __read_mostly;
 369 static int ftrace_profile_enabled __read_mostly;
 370
 371 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
 372 static DEFINE_MUTEX(ftrace_profile_lock);
 373
 374 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
 375
 376 #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
 377
 378 static void *
 379 function_stat_next(void *v, int idx)
 380 {
 381         struct ftrace_profile *rec = v;
 382         struct ftrace_profile_page *pg;
 383
 384         pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
 385
 386  again:
 387         if (idx != 0)
 388                 rec++;
 389
 390         if ((void *)rec >= (void *)&pg->records[pg->index]) {
 391                 pg = pg->next;
 392                 if (!pg)
 393                         return NULL;
 394                 rec = &pg->records[0];
 395                 if (!rec->counter)
 396                         goto again;
 397         }
 398
 399         return rec;
 400 }
 401
 402 static void *function_stat_start(struct tracer_stat *trace)
 403 {
 404         struct ftrace_profile_stat *stat =
 405                 container_of(trace, struct ftrace_profile_stat, stat);
 406
 407         if (!stat || !stat->start)
 408                 return NULL;
 409
 410         return function_stat_next(&stat->start->records[0], 0);
 411 }
 412
 413 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 414 /* function graph compares on total time */
 415 static int function_stat_cmp(void *p1, void *p2)
 416 {
 417         struct ftrace_profile *a = p1;
 418         struct ftrace_profile *b = p2;
 419
 420         if (a->time < b->time)
 421                 return -1;
 422         if (a->time > b->time)
 423                 return 1;
 424         else
 425                 return 0;
 426 }
 427 #else
 428 /* not function graph compares against hits */
 429 static int function_stat_cmp(void *p1, void *p2)
 430 {
 431         struct ftrace_profile *a = p1;
 432         struct ftrace_profile *b = p2;
 433
 434         if (a->counter < b->counter)
 435                 return -1;
 436         if (a->counter > b->counter)
 437                 return 1;
 438         else
 439                 return 0;
 440 }
 441 #endif
 442
 443 static int function_stat_headers(struct seq_file *m)
 444 {
 445 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 446         seq_printf(m, "  Function                               "
 447                    "Hit    Time            Avg             s^2\n"
 448                       "  --------                               "
 449                    "---    ----            ---             ---\n");
 450 #else
 451         seq_printf(m, "  Function                               Hit\n"
 452                       "  --------                               ---\n");
 453 #endif
 454         return 0;
 455 }
 456
 457 static int function_stat_show(struct seq_file *m, void *v)
 458 {
 459         struct ftrace_profile *rec = v;
 460         char str[KSYM_SYMBOL_LEN];
 461         int ret = 0;
 462 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 463         static struct trace_seq s;
 464         unsigned long long avg;
 465         unsigned long long stddev;
 466 #endif
 467         mutex_lock(&ftrace_profile_lock);
 468
 469         /* we raced with function_profile_reset() */
 470         if (unlikely(rec->counter == 0)) {
 471                 ret = -EBUSY;
 472                 goto out;
 473         }
 474
 475         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 476         seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);
 477
 478 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 479         seq_printf(m, "    ");
 480         avg = rec->time;
 481         do_div(avg, rec->counter);
 482
 483         /* Sample standard deviation (s^2) */
 484         if (rec->counter <= 1)
 485                 stddev = 0;
 486         else {
 487                 stddev = rec->time_squared - rec->counter * avg * avg;
 488                 /*
 489                  * Divide only 1000 for ns^2 -> us^2 conversion.
 490                  * trace_print_graph_duration will divide 1000 again.
 491                  */
 492                 do_div(stddev, (rec->counter - 1) * 1000);
 493         }
 494
 495         trace_seq_init(&s);
 496         trace_print_graph_duration(rec->time, &s);
 497         trace_seq_puts(&s, "    ");
 498         trace_print_graph_duration(avg, &s);
 499         trace_seq_puts(&s, "    ");
 500         trace_print_graph_duration(stddev, &s);
 501         trace_print_seq(m, &s);
 502 #endif
 503         seq_putc(m, '\n');
 504 out:
 505         mutex_unlock(&ftrace_profile_lock);
 506
 507         return ret;
 508 }
 509
 510 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
 511 {
 512         struct ftrace_profile_page *pg;
 513
 514         pg = stat->pages = stat->start;
 515
 516         while (pg) {
 517                 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
 518                 pg->index = 0;
 519                 pg = pg->next;
 520         }
 521
 522         memset(stat->hash, 0,
 523                FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
 524 }
 525
 526 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
 527 {
 528         struct ftrace_profile_page *pg;
 529         int functions;
 530         int pages;
 531         int i;
 532
 533         /* If we already allocated, do nothing */
 534         if (stat->pages)
 535                 return 0;
 536
 537         stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
 538         if (!stat->pages)
 539                 return -ENOMEM;
 540
 541 #ifdef CONFIG_DYNAMIC_FTRACE
 542         functions = ftrace_update_tot_cnt;
 543 #else
 544         /*
 545          * We do not know the number of functions that exist because
 546          * dynamic tracing is what counts them. With past experience
 547          * we have around 20K functions. That should be more than enough.
 548          * It is highly unlikely we will execute every function in
 549          * the kernel.
 550          */
 551         functions = 20000;
 552 #endif
 553
 554         pg = stat->start = stat->pages;
 555
 556         pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
 557
 558         for (i = 0; i < pages; i++) {
 559                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
 560                 if (!pg->next)
 561                         goto out_free;
 562                 pg = pg->next;
 563         }
 564
 565         return 0;
 566
 567  out_free:
 568         pg = stat->start;
 569         while (pg) {
 570                 unsigned long tmp = (unsigned long)pg;
 571
 572                 pg = pg->next;
 573                 free_page(tmp);
 574         }
 575
 576         free_page((unsigned long)stat->pages);
 577         stat->pages = NULL;
 578         stat->start = NULL;
 579
 580         return -ENOMEM;
 581 }
 582
 583 static int ftrace_profile_init_cpu(int cpu)
 584 {
 585         struct ftrace_profile_stat *stat;
 586         int size;
 587
 588         stat = &per_cpu(ftrace_profile_stats, cpu);
 589
 590         if (stat->hash) {
 591                 /* If the profile is already created, simply reset it */
 592                 ftrace_profile_reset(stat);
 593                 return 0;
 594         }
 595
 596         /*
 597          * We are profiling all functions, but usually only a few thousand
 598          * functions are hit. We'll make a hash of 1024 items.
 599          */
 600         size = FTRACE_PROFILE_HASH_SIZE;
 601
 602         stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
 603
 604         if (!stat->hash)
 605                 return -ENOMEM;
 606
 607         if (!ftrace_profile_bits) {
 608                 size--;
 609
 610                 for (; size; size >>= 1)
 611                         ftrace_profile_bits++;
 612         }
 613
 614         /* Preallocate the function profiling pages */
 615         if (ftrace_profile_pages_init(stat) < 0) {
 616                 kfree(stat->hash);
 617                 stat->hash = NULL;
 618                 return -ENOMEM;
 619         }
 620
 621         return 0;
 622 }
 623
 624 static int ftrace_profile_init(void)
 625 {
 626         int cpu;
 627         int ret = 0;
 628
 629         for_each_online_cpu(cpu) {
 630                 ret = ftrace_profile_init_cpu(cpu);
 631                 if (ret)
 632                         break;
 633         }
 634
 635         return ret;
 636 }
 637
 638 /* interrupts must be disabled */
 639 static struct ftrace_profile *
 640 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
 641 {
 642         struct ftrace_profile *rec;
 643         struct hlist_head *hhd;
 644         struct hlist_node *n;
 645         unsigned long key;
 646
 647         key = hash_long(ip, ftrace_profile_bits);
 648         hhd = &stat->hash[key];
 649
 650         if (hlist_empty(hhd))
 651                 return NULL;
 652
 653         hlist_for_each_entry_rcu(rec, n, hhd, node) {
 654                 if (rec->ip == ip)
 655                         return rec;
 656         }
 657
 658         return NULL;
 659 }
 660
 661 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
 662                                struct ftrace_profile *rec)
 663 {
 664         unsigned long key;
 665
 666         key = hash_long(rec->ip, ftrace_profile_bits);
 667         hlist_add_head_rcu(&rec->node, &stat->hash[key]);
 668 }
 669
 670 /*
 671  * The memory is already allocated, this simply finds a new record to use.
 672  */
 673 static struct ftrace_profile *
 674 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
 675 {
 676         struct ftrace_profile *rec = NULL;
 677
 678         /* prevent recursion (from NMIs) */
 679         if (atomic_inc_return(&stat->disabled) != 1)
 680                 goto out;
 681
 682         /*
 683          * Try to find the function again since an NMI
 684          * could have added it
 685          */
 686         rec = ftrace_find_profiled_func(stat, ip);
 687         if (rec)
 688                 goto out;
 689
 690         if (stat->pages->index == PROFILES_PER_PAGE) {
 691                 if (!stat->pages->next)
 692                         goto out;
 693                 stat->pages = stat->pages->next;
 694         }
 695
 696         rec = &stat->pages->records[stat->pages->index++];
 697         rec->ip = ip;
 698         ftrace_add_profile(stat, rec);
 699
 700  out:
 701         atomic_dec(&stat->disabled);
 702
 703         return rec;
 704 }
 705
 706 static void
 707 function_profile_call(unsigned long ip, unsigned long parent_ip)
 708 {
 709         struct ftrace_profile_stat *stat;
 710         struct ftrace_profile *rec;
 711         unsigned long flags;
 712
 713         if (!ftrace_profile_enabled)
 714                 return;
 715
 716         local_irq_save(flags);
 717
 718         stat = &__get_cpu_var(ftrace_profile_stats);
 719         if (!stat->hash || !ftrace_profile_enabled)
 720                 goto out;
 721
 722         rec = ftrace_find_profiled_func(stat, ip);
 723         if (!rec) {
 724                 rec = ftrace_profile_alloc(stat, ip);
 725                 if (!rec)
 726                         goto out;
 727         }
 728
 729         rec->counter++;
 730  out:
 731         local_irq_restore(flags);
 732 }
 733
 734 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 735 static int profile_graph_entry(struct ftrace_graph_ent *trace)
 736 {
 737         function_profile_call(trace->func, 0);
 738         return 1;
 739 }
 740
 741 static void profile_graph_return(struct ftrace_graph_ret *trace)
 742 {
 743         struct ftrace_profile_stat *stat;
 744         unsigned long long calltime;
 745         struct ftrace_profile *rec;
 746         unsigned long flags;
 747
 748         local_irq_save(flags);
 749         stat = &__get_cpu_var(ftrace_profile_stats);
 750         if (!stat->hash || !ftrace_profile_enabled)
 751                 goto out;
 752
 753         /* If the calltime was zero'd ignore it */
 754         if (!trace->calltime)
 755                 goto out;
 756
 757         calltime = trace->rettime - trace->calltime;
 758
 759         if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
 760                 int index;
 761
 762                 index = trace->depth;
 763
 764                 /* Append this call time to the parent time to subtract */
 765                 if (index)
 766                         current->ret_stack[index - 1].subtime += calltime;
 767
 768                 if (current->ret_stack[index].subtime < calltime)
 769                         calltime -= current->ret_stack[index].subtime;
 770                 else
 771                         calltime = 0;
 772         }
 773
 774         rec = ftrace_find_profiled_func(stat, trace->func);
 775         if (rec) {
 776                 rec->time += calltime;
 777                 rec->time_squared += calltime * calltime;
 778         }
 779
 780  out:
 781         local_irq_restore(flags);
 782 }
 783
 784 static int register_ftrace_profiler(void)
 785 {
 786         return register_ftrace_graph(&profile_graph_return,
 787                                      &profile_graph_entry);
 788 }
 789
 790 static void unregister_ftrace_profiler(void)
 791 {
 792         unregister_ftrace_graph();
 793 }
 794 #else
 795 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
 796         .func           = function_profile_call,
 797 };
 798
 799 static int register_ftrace_profiler(void)
 800 {
 801         return register_ftrace_function(&ftrace_profile_ops);
 802 }
 803
 804 static void unregister_ftrace_profiler(void)
 805 {
 806         unregister_ftrace_function(&ftrace_profile_ops);
 807 }
 808 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 809
 810 static ssize_t
 811 ftrace_profile_write(struct file *filp, const char __user *ubuf,
 812                      size_t cnt, loff_t *ppos)
 813 {
 814         unsigned long val;
 815         int ret;
 816
 817         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
 818         if (ret)
 819                 return ret;
 820
 821         val = !!val;
 822
 823         mutex_lock(&ftrace_profile_lock);
 824         if (ftrace_profile_enabled ^ val) {
 825                 if (val) {
 826                         ret = ftrace_profile_init();
 827                         if (ret < 0) {
 828                                 cnt = ret;
 829                                 goto out;
 830                         }
 831
 832                         ret = register_ftrace_profiler();
 833                         if (ret < 0) {
 834                                 cnt = ret;
 835                                 goto out;
 836                         }
 837                         ftrace_profile_enabled = 1;
 838                 } else {
 839                         ftrace_profile_enabled = 0;
 840                         /*
 841                          * unregister_ftrace_profiler calls stop_machine
 842                          * so this acts like an synchronize_sched.
 843                          */
 844                         unregister_ftrace_profiler();
 845                 }
 846         }
 847  out:
 848         mutex_unlock(&ftrace_profile_lock);
 849
 850         *ppos += cnt;
 851
 852         return cnt;
 853 }
 854
 855 static ssize_t
 856 ftrace_profile_read(struct file *filp, char __user *ubuf,
 857                      size_t cnt, loff_t *ppos)
 858 {
 859         char buf[64];           /* big enough to hold a number */
 860         int r;
 861
 862         r = sprintf(buf, "%u\n", ftrace_profile_enabled);
 863         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 864 }
 865
 866 static const struct file_operations ftrace_profile_fops = {
 867         .open           = tracing_open_generic,
 868         .read           = ftrace_profile_read,
 869         .write          = ftrace_profile_write,
 870         .llseek         = default_llseek,
 871 };
 872
 873 /* used to initialize the real stat files */
 874 static struct tracer_stat function_stats __initdata = {
 875         .name           = "functions",
 876         .stat_start     = function_stat_start,
 877         .stat_next      = function_stat_next,
 878         .stat_cmp       = function_stat_cmp,
 879         .stat_headers   = function_stat_headers,
 880         .stat_show      = function_stat_show
 881 };
 882
 883 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
 884 {
 885         struct ftrace_profile_stat *stat;
 886         struct dentry *entry;
 887         char *name;
 888         int ret;
 889         int cpu;
 890
 891         for_each_possible_cpu(cpu) {
 892                 stat = &per_cpu(ftrace_profile_stats, cpu);
 893
 894                 /* allocate enough for function name + cpu number */
 895                 name = kmalloc(32, GFP_KERNEL);
 896                 if (!name) {
 897                         /*
 898                          * The files created are permanent, if something happens
 899                          * we still do not free memory.
 900                          */
 901                         WARN(1,
 902                              "Could not allocate stat file for cpu %d\n",
 903                              cpu);
 904                         return;
 905                 }
 906                 stat->stat = function_stats;
 907                 snprintf(name, 32, "function%d", cpu);
 908                 stat->stat.name = name;
 909                 ret = register_stat_tracer(&stat->stat);
 910                 if (ret) {
 911                         WARN(1,
 912                              "Could not register function stat for cpu %d\n",
 913                              cpu);
 914                         kfree(name);
 915                         return;
 916                 }
 917         }
 918
 919         entry = debugfs_create_file("function_profile_enabled", 0644,
 920                                     d_tracer, NULL, &ftrace_profile_fops);
 921         if (!entry)
 922                 pr_warning("Could not create debugfs "
 923                            "'function_profile_enabled' entry\n");
 924 }
 925
 926 #else /* CONFIG_FUNCTION_PROFILER */
 927 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
 928 {
 929 }
 930 #endif /* CONFIG_FUNCTION_PROFILER */
 931
 932 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
 933
 934 #ifdef CONFIG_DYNAMIC_FTRACE
 935
 936 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
 937 # error Dynamic ftrace depends on MCOUNT_RECORD
 938 #endif
 939
 940 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
 941
 942 struct ftrace_func_probe {
 943         struct hlist_node       node;
 944         struct ftrace_probe_ops *ops;
 945         unsigned long           flags;
 946         unsigned long           ip;
 947         void                    *data;
 948         struct rcu_head         rcu;
 949 };
 950
 951 enum {
 952         FTRACE_ENABLE_CALLS             = (1 << 0),
 953         FTRACE_DISABLE_CALLS            = (1 << 1),
 954         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 955         FTRACE_START_FUNC_RET           = (1 << 3),
 956         FTRACE_STOP_FUNC_RET            = (1 << 4),
 957 };
 958 struct ftrace_func_entry {
 959         struct hlist_node hlist;
 960         unsigned long ip;
 961 };
 962
 963 struct ftrace_hash {
 964         unsigned long           size_bits;
 965         struct hlist_head       *buckets;
 966         unsigned long           count;
 967         struct rcu_head         rcu;
 968 };
 969
 970 /*
 971  * We make these constant because no one should touch them,
 972  * but they are used as the default "empty hash", to avoid allocating
 973  * it all the time. These are in a read only section such that if
 974  * anyone does try to modify it, it will cause an exception.
 975  */
 976 static const struct hlist_head empty_buckets[1];
 977 static const struct ftrace_hash empty_hash = {
 978         .buckets = (struct hlist_head *)empty_buckets,
 979 };
 980 #define EMPTY_HASH      ((struct ftrace_hash *)&empty_hash)
 981
 982 static struct ftrace_ops global_ops = {
 983         .func                   = ftrace_stub,
 984         .notrace_hash           = EMPTY_HASH,
 985         .filter_hash            = EMPTY_HASH,
 986 };
 987
 988 static struct dyn_ftrace *ftrace_new_addrs;
 989
 990 static DEFINE_MUTEX(ftrace_regex_lock);
 991
 992 struct ftrace_page {
 993         struct ftrace_page      *next;
 994         int                     index;
 995         struct dyn_ftrace       records[];
 996 };
 997
 998 #define ENTRIES_PER_PAGE \
 999   ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
1000
1001 /* estimate from running different kernels */
1002 #define NR_TO_INIT              10000
1003
1004 static struct ftrace_page       *ftrace_pages_start;
1005 static struct ftrace_page       *ftrace_pages;
1006
1007 static struct dyn_ftrace *ftrace_free_records;
1008
1009 static struct ftrace_func_entry *
1010 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1011 {
1012         unsigned long key;
1013         struct ftrace_func_entry *entry;
1014         struct hlist_head *hhd;
1015         struct hlist_node *n;
1016
1017         if (!hash->count)
1018                 return NULL;
1019
1020         if (hash->size_bits > 0)
1021                 key = hash_long(ip, hash->size_bits);
1022         else
1023                 key = 0;
1024
1025         hhd = &hash->buckets[key];
1026
1027         hlist_for_each_entry_rcu(entry, n, hhd, hlist) {
1028                 if (entry->ip == ip)
1029                         return entry;
1030         }
1031         return NULL;
1032 }
1033
1034 static void __add_hash_entry(struct ftrace_hash *hash,
1035                              struct ftrace_func_entry *entry)
1036 {
1037         struct hlist_head *hhd;
1038         unsigned long key;
1039
1040         if (hash->size_bits)
1041                 key = hash_long(entry->ip, hash->size_bits);
1042         else
1043                 key = 0;
1044
1045         hhd = &hash->buckets[key];
1046         hlist_add_head(&entry->hlist, hhd);
1047         hash->count++;
1048 }
1049
1050 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1051 {
1052         struct ftrace_func_entry *entry;
1053
1054         entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1055         if (!entry)
1056                 return -ENOMEM;
1057
1058         entry->ip = ip;
1059         __add_hash_entry(hash, entry);
1060
1061         return 0;
1062 }
1063
1064 static void
1065 free_hash_entry(struct ftrace_hash *hash,
1066                   struct ftrace_func_entry *entry)
1067 {
1068         hlist_del(&entry->hlist);
1069         kfree(entry);
1070         hash->count--;
1071 }
1072
1073 static void
1074 remove_hash_entry(struct ftrace_hash *hash,
1075                   struct ftrace_func_entry *entry)
1076 {
1077         hlist_del(&entry->hlist);
1078         hash->count--;
1079 }
1080
1081 static void ftrace_hash_clear(struct ftrace_hash *hash)
1082 {
1083         struct hlist_head *hhd;
1084         struct hlist_node *tp, *tn;
1085         struct ftrace_func_entry *entry;
1086         int size = 1 << hash->size_bits;
1087         int i;
1088
1089         if (!hash->count)
1090                 return;
1091
1092         for (i = 0; i < size; i++) {
1093                 hhd = &hash->buckets[i];
1094                 hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist)
1095                         free_hash_entry(hash, entry);
1096         }
1097         FTRACE_WARN_ON(hash->count);
1098 }
1099
1100 static void free_ftrace_hash(struct ftrace_hash *hash)
1101 {
1102         if (!hash || hash == EMPTY_HASH)
1103                 return;
1104         ftrace_hash_clear(hash);
1105         kfree(hash->buckets);
1106         kfree(hash);
1107 }
1108
1109 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1110 {
1111         struct ftrace_hash *hash;
1112
1113         hash = container_of(rcu, struct ftrace_hash, rcu);
1114         free_ftrace_hash(hash);
1115 }
1116
1117 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1118 {
1119         if (!hash || hash == EMPTY_HASH)
1120                 return;
1121         call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1122 }
1123
1124 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1125 {
1126         struct ftrace_hash *hash;
1127         int size;
1128
1129         hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1130         if (!hash)
1131                 return NULL;
1132
1133         size = 1 << size_bits;
1134         hash->buckets = kzalloc(sizeof(*hash->buckets) * size, GFP_KERNEL);
1135
1136         if (!hash->buckets) {
1137                 kfree(hash);
1138                 return NULL;
1139         }
1140
1141         hash->size_bits = size_bits;
1142
1143         return hash;
1144 }
1145
1146 static struct ftrace_hash *
1147 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1148 {
1149         struct ftrace_func_entry *entry;
1150         struct ftrace_hash *new_hash;
1151         struct hlist_node *tp;
1152         int size;
1153         int ret;
1154         int i;
1155
1156         new_hash = alloc_ftrace_hash(size_bits);
1157         if (!new_hash)
1158                 return NULL;
1159
1160         /* Empty hash? */
1161         if (!hash || !hash->count)
1162                 return new_hash;
1163
1164         size = 1 << hash->size_bits;
1165         for (i = 0; i < size; i++) {
1166                 hlist_for_each_entry(entry, tp, &hash->buckets[i], hlist) {
1167                         ret = add_hash_entry(new_hash, entry->ip);
1168                         if (ret < 0)
1169                                 goto free_hash;
1170                 }
1171         }
1172
1173         FTRACE_WARN_ON(new_hash->count != hash->count);
1174
1175         return new_hash;
1176
1177  free_hash:
1178         free_ftrace_hash(new_hash);
1179         return NULL;
1180 }
1181
1182 static void
1183 ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
1184 static void
1185 ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
1186
1187 static int
1188 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1189                  struct ftrace_hash **dst, struct ftrace_hash *src)
1190 {
1191         struct ftrace_func_entry *entry;
1192         struct hlist_node *tp, *tn;
1193         struct hlist_head *hhd;
1194         struct ftrace_hash *old_hash;
1195         struct ftrace_hash *new_hash;
1196         unsigned long key;
1197         int size = src->count;
1198         int bits = 0;
1199         int ret;
1200         int i;
1201
1202         /*
1203          * Remove the current set, update the hash and add
1204          * them back.
1205          */
1206         ftrace_hash_rec_disable(ops, enable);
1207
1208         /*
1209          * If the new source is empty, just free dst and assign it
1210          * the empty_hash.
1211          */
1212         if (!src->count) {
1213                 free_ftrace_hash_rcu(*dst);
1214                 rcu_assign_pointer(*dst, EMPTY_HASH);
1215                 return 0;
1216         }
1217
1218         /*
1219          * Make the hash size about 1/2 the # found
1220          */
1221         for (size /= 2; size; size >>= 1)
1222                 bits++;
1223
1224         /* Don't allocate too much */
1225         if (bits > FTRACE_HASH_MAX_BITS)
1226                 bits = FTRACE_HASH_MAX_BITS;
1227
1228         ret = -ENOMEM;
1229         new_hash = alloc_ftrace_hash(bits);
1230         if (!new_hash)
1231                 goto out;
1232
1233         size = 1 << src->size_bits;
1234         for (i = 0; i < size; i++) {
1235                 hhd = &src->buckets[i];
1236                 hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist) {
1237                         if (bits > 0)
1238                                 key = hash_long(entry->ip, bits);
1239                         else
1240                                 key = 0;
1241                         remove_hash_entry(src, entry);
1242                         __add_hash_entry(new_hash, entry);
1243                 }
1244         }
1245
1246         old_hash = *dst;
1247         rcu_assign_pointer(*dst, new_hash);
1248         free_ftrace_hash_rcu(old_hash);
1249
1250         ret = 0;
1251  out:
1252         /*
1253          * Enable regardless of ret:
1254          *  On success, we enable the new hash.
1255          *  On failure, we re-enable the original hash.
1256          */
1257         ftrace_hash_rec_enable(ops, enable);
1258
1259         return ret;
1260 }
1261
1262 /*
1263  * Test the hashes for this ops to see if we want to call
1264  * the ops->func or not.
1265  *
1266  * It's a match if the ip is in the ops->filter_hash or
1267  * the filter_hash does not exist or is empty,
1268  *  AND
1269  * the ip is not in the ops->notrace_hash.
1270  *
1271  * This needs to be called with preemption disabled as
1272  * the hashes are freed with call_rcu_sched().
1273  */
1274 static int
1275 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
1276 {
1277         struct ftrace_hash *filter_hash;
1278         struct ftrace_hash *notrace_hash;
1279         int ret;
1280
1281         filter_hash = rcu_dereference_raw(ops->filter_hash);
1282         notrace_hash = rcu_dereference_raw(ops->notrace_hash);
1283
1284         if ((!filter_hash || !filter_hash->count ||
1285              ftrace_lookup_ip(filter_hash, ip)) &&
1286             (!notrace_hash || !notrace_hash->count ||
1287              !ftrace_lookup_ip(notrace_hash, ip)))
1288                 ret = 1;
1289         else
1290                 ret = 0;
1291
1292         return ret;
1293 }
1294
1295 /*
1296  * This is a double for. Do not use 'break' to break out of the loop,
1297  * you must use a goto.
1298  */
1299 #define do_for_each_ftrace_rec(pg, rec)                                 \
1300         for (pg = ftrace_pages_start; pg; pg = pg->next) {              \
1301                 int _____i;                                             \
1302                 for (_____i = 0; _____i < pg->index; _____i++) {        \
1303                         rec = &pg->records[_____i];
1304
1305 #define while_for_each_ftrace_rec()             \
1306                 }                               \
1307         }
1308
1309 static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
1310                                      int filter_hash,
1311                                      bool inc)
1312 {
1313         struct ftrace_hash *hash;
1314         struct ftrace_hash *other_hash;
1315         struct ftrace_page *pg;
1316         struct dyn_ftrace *rec;
1317         int count = 0;
1318         int all = 0;
1319
1320         /* Only update if the ops has been registered */
1321         if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1322                 return;
1323
1324         /*
1325          * In the filter_hash case:
1326          *   If the count is zero, we update all records.
1327          *   Otherwise we just update the items in the hash.
1328          *
1329          * In the notrace_hash case:
1330          *   We enable the update in the hash.
1331          *   As disabling notrace means enabling the tracing,
1332          *   and enabling notrace means disabling, the inc variable
1333          *   gets inversed.
1334          */
1335         if (filter_hash) {
1336                 hash = ops->filter_hash;
1337                 other_hash = ops->notrace_hash;
1338                 if (!hash || !hash->count)
1339                         all = 1;
1340         } else {
1341                 inc = !inc;
1342                 hash = ops->notrace_hash;
1343                 other_hash = ops->filter_hash;
1344                 /*
1345                  * If the notrace hash has no items,
1346                  * then there's nothing to do.
1347                  */
1348                 if (hash && !hash->count)
1349                         return;
1350         }
1351
1352         do_for_each_ftrace_rec(pg, rec) {
1353                 int in_other_hash = 0;
1354                 int in_hash = 0;
1355                 int match = 0;
1356
1357                 if (all) {
1358                         /*
1359                          * Only the filter_hash affects all records.
1360                          * Update if the record is not in the notrace hash.
1361                          */
1362                         if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1363                                 match = 1;
1364                 } else {
1365                         in_hash = hash && !!ftrace_lookup_ip(hash, rec->ip);
1366                         in_other_hash = other_hash && !!ftrace_lookup_ip(other_hash, rec->ip);
1367
1368                         /*
1369                          *
1370                          */
1371                         if (filter_hash && in_hash && !in_other_hash)
1372                                 match = 1;
1373                         else if (!filter_hash && in_hash &&
1374                                  (in_other_hash || !other_hash->count))
1375                                 match = 1;
1376                 }
1377                 if (!match)
1378                         continue;
1379
1380                 if (inc) {
1381                         rec->flags++;
1382                         if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
1383                                 return;
1384                 } else {
1385                         if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
1386                                 return;
1387                         rec->flags--;
1388                 }
1389                 count++;
1390                 /* Shortcut, if we handled all records, we are done. */
1391                 if (!all && count == hash->count)
1392                         return;
1393         } while_for_each_ftrace_rec();
1394 }
1395
1396 static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1397                                     int filter_hash)
1398 {
1399         __ftrace_hash_rec_update(ops, filter_hash, 0);
1400 }
1401
1402 static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1403                                    int filter_hash)
1404 {
1405         __ftrace_hash_rec_update(ops, filter_hash, 1);
1406 }
1407
1408 static void ftrace_free_rec(struct dyn_ftrace *rec)
1409 {
1410         rec->freelist = ftrace_free_records;
1411         ftrace_free_records = rec;
1412         rec->flags |= FTRACE_FL_FREE;
1413 }
1414
1415 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
1416 {
1417         struct dyn_ftrace *rec;
1418
1419         /* First check for freed records */
1420         if (ftrace_free_records) {
1421                 rec = ftrace_free_records;
1422
1423                 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
1424                         FTRACE_WARN_ON_ONCE(1);
1425                         ftrace_free_records = NULL;
1426                         return NULL;
1427                 }
1428
1429                 ftrace_free_records = rec->freelist;
1430                 memset(rec, 0, sizeof(*rec));
1431                 return rec;
1432         }
1433
1434         if (ftrace_pages->index == ENTRIES_PER_PAGE) {
1435                 if (!ftrace_pages->next) {
1436                         /* allocate another page */
1437                         ftrace_pages->next =
1438                                 (void *)get_zeroed_page(GFP_KERNEL);
1439                         if (!ftrace_pages->next)
1440                                 return NULL;
1441                 }
1442                 ftrace_pages = ftrace_pages->next;
1443         }
1444
1445         return &ftrace_pages->records[ftrace_pages->index++];
1446 }
1447
1448 static struct dyn_ftrace *
1449 ftrace_record_ip(unsigned long ip)
1450 {
1451         struct dyn_ftrace *rec;
1452
1453         if (ftrace_disabled)
1454                 return NULL;
1455
1456         rec = ftrace_alloc_dyn_node(ip);
1457         if (!rec)
1458                 return NULL;
1459
1460         rec->ip = ip;
1461         rec->newlist = ftrace_new_addrs;
1462         ftrace_new_addrs = rec;
1463
1464         return rec;
1465 }
1466
1467 static void print_ip_ins(const char *fmt, unsigned char *p)
1468 {
1469         int i;
1470
1471         printk(KERN_CONT "%s", fmt);
1472
1473         for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1474                 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1475 }
1476
1477 static void ftrace_bug(int failed, unsigned long ip)
1478 {
1479         switch (failed) {
1480         case -EFAULT:
1481                 FTRACE_WARN_ON_ONCE(1);
1482                 pr_info("ftrace faulted on modifying ");
1483                 print_ip_sym(ip);
1484                 break;
1485         case -EINVAL:
1486                 FTRACE_WARN_ON_ONCE(1);
1487                 pr_info("ftrace failed to modify ");
1488                 print_ip_sym(ip);
1489                 print_ip_ins(" actual: ", (unsigned char *)ip);
1490                 printk(KERN_CONT "\n");
1491                 break;
1492         case -EPERM:
1493                 FTRACE_WARN_ON_ONCE(1);
1494                 pr_info("ftrace faulted on writing ");
1495                 print_ip_sym(ip);
1496                 break;
1497         default:
1498                 FTRACE_WARN_ON_ONCE(1);
1499                 pr_info("ftrace faulted on unknown error ");
1500                 print_ip_sym(ip);
1501         }
1502 }
1503
1504
1505 /* Return 1 if the address range is reserved for ftrace */
1506 int ftrace_text_reserved(void *start, void *end)
1507 {
1508         struct dyn_ftrace *rec;
1509         struct ftrace_page *pg;
1510
1511         do_for_each_ftrace_rec(pg, rec) {
1512                 if (rec->ip <= (unsigned long)end &&
1513                     rec->ip + MCOUNT_INSN_SIZE > (unsigned long)start)
1514                         return 1;
1515         } while_for_each_ftrace_rec();
1516         return 0;
1517 }
1518
1519
1520 static int
1521 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1522 {
1523         unsigned long ftrace_addr;
1524         unsigned long flag = 0UL;
1525
1526         ftrace_addr = (unsigned long)FTRACE_ADDR;
1527
1528         /*
1529          * If we are enabling tracing:
1530          *
1531          *   If the record has a ref count, then we need to enable it
1532          *   because someone is using it.
1533          *
1534          *   Otherwise we make sure its disabled.
1535          *
1536          * If we are disabling tracing, then disable all records that
1537          * are enabled.
1538          */
1539         if (enable && (rec->flags & ~FTRACE_FL_MASK))
1540                 flag = FTRACE_FL_ENABLED;
1541
1542         /* If the state of this record hasn't changed, then do nothing */
1543         if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1544                 return 0;
1545
1546         if (flag) {
1547                 rec->flags |= FTRACE_FL_ENABLED;
1548                 return ftrace_make_call(rec, ftrace_addr);
1549         }
1550
1551         rec->flags &= ~FTRACE_FL_ENABLED;
1552         return ftrace_make_nop(NULL, rec, ftrace_addr);
1553 }
1554
1555 static void ftrace_replace_code(int enable)
1556 {
1557         struct dyn_ftrace *rec;
1558         struct ftrace_page *pg;
1559         int failed;
1560
1561         if (unlikely(ftrace_disabled))
1562                 return;
1563
1564         do_for_each_ftrace_rec(pg, rec) {
1565                 /* Skip over free records */
1566                 if (rec->flags & FTRACE_FL_FREE)
1567                         continue;
1568
1569                 failed = __ftrace_replace_code(rec, enable);
1570                 if (failed) {
1571                         ftrace_bug(failed, rec->ip);
1572                         /* Stop processing */
1573                         return;
1574                 }
1575         } while_for_each_ftrace_rec();
1576 }
1577
1578 static int
1579 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1580 {
1581         unsigned long ip;
1582         int ret;
1583
1584         ip = rec->ip;
1585
1586         if (unlikely(ftrace_disabled))
1587                 return 0;
1588
1589         ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1590         if (ret) {
1591                 ftrace_bug(ret, ip);
1592                 return 0;
1593         }
1594         return 1;
1595 }
1596
1597 /*
1598  * archs can override this function if they must do something
1599  * before the modifying code is performed.
1600  */
1601 int __weak ftrace_arch_code_modify_prepare(void)
1602 {
1603         return 0;
1604 }
1605
1606 /*
1607  * archs can override this function if they must do something
1608  * after the modifying code is performed.
1609  */
1610 int __weak ftrace_arch_code_modify_post_process(void)
1611 {
1612         return 0;
1613 }
1614
1615 static int __ftrace_modify_code(void *data)
1616 {
1617         int *command = data;
1618
1619         /*
1620          * Do not call function tracer while we update the code.
1621          * We are in stop machine, no worrying about races.
1622          */
1623         function_trace_stop++;
1624
1625         if (*command & FTRACE_ENABLE_CALLS)
1626                 ftrace_replace_code(1);
1627         else if (*command & FTRACE_DISABLE_CALLS)
1628                 ftrace_replace_code(0);
1629
1630         if (*command & FTRACE_UPDATE_TRACE_FUNC)
1631                 ftrace_update_ftrace_func(ftrace_trace_function);
1632
1633         if (*command & FTRACE_START_FUNC_RET)
1634                 ftrace_enable_ftrace_graph_caller();
1635         else if (*command & FTRACE_STOP_FUNC_RET)
1636                 ftrace_disable_ftrace_graph_caller();
1637
1638 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
1639         /*
1640          * For archs that call ftrace_test_stop_func(), we must
1641          * wait till after we update all the function callers
1642          * before we update the callback. This keeps different
1643          * ops that record different functions from corrupting
1644          * each other.
1645          */
1646         __ftrace_trace_function = __ftrace_trace_function_delay;
1647 #endif
1648         function_trace_stop--;
1649
1650         return 0;
1651 }
1652
1653 static void ftrace_run_update_code(int command)
1654 {
1655         int ret;
1656
1657         ret = ftrace_arch_code_modify_prepare();
1658         FTRACE_WARN_ON(ret);
1659         if (ret)
1660                 return;
1661
1662         stop_machine(__ftrace_modify_code, &command, NULL);
1663
1664         ret = ftrace_arch_code_modify_post_process();
1665         FTRACE_WARN_ON(ret);
1666 }
1667
1668 static ftrace_func_t saved_ftrace_func;
1669 static int ftrace_start_up;
1670 static int global_start_up;
1671
1672 static void ftrace_startup_enable(int command)
1673 {
1674         if (saved_ftrace_func != ftrace_trace_function) {
1675                 saved_ftrace_func = ftrace_trace_function;
1676                 command |= FTRACE_UPDATE_TRACE_FUNC;
1677         }
1678
1679         if (!command || !ftrace_enabled)
1680                 return;
1681
1682         ftrace_run_update_code(command);
1683 }
1684
1685 static int ftrace_startup(struct ftrace_ops *ops, int command)
1686 {
1687         bool hash_enable = true;
1688
1689         if (unlikely(ftrace_disabled))
1690                 return -ENODEV;
1691
1692         ftrace_start_up++;
1693         command |= FTRACE_ENABLE_CALLS;
1694
1695         /* ops marked global share the filter hashes */
1696         if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1697                 ops = &global_ops;
1698                 /* Don't update hash if global is already set */
1699                 if (global_start_up)
1700                         hash_enable = false;
1701                 global_start_up++;
1702         }
1703
1704         ops->flags |= FTRACE_OPS_FL_ENABLED;
1705         if (hash_enable)
1706                 ftrace_hash_rec_enable(ops, 1);
1707
1708         ftrace_startup_enable(command);
1709
1710         return 0;
1711 }
1712
1713 static void ftrace_shutdown(struct ftrace_ops *ops, int command)
1714 {
1715         bool hash_disable = true;
1716
1717         if (unlikely(ftrace_disabled))
1718                 return;
1719
1720         ftrace_start_up--;
1721         /*
1722          * Just warn in case of unbalance, no need to kill ftrace, it's not
1723          * critical but the ftrace_call callers may be never nopped again after
1724          * further ftrace uses.
1725          */
1726         WARN_ON_ONCE(ftrace_start_up < 0);
1727
1728         if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1729                 ops = &global_ops;
1730                 global_start_up--;
1731                 WARN_ON_ONCE(global_start_up < 0);
1732                 /* Don't update hash if global still has users */
1733                 if (global_start_up) {
1734                         WARN_ON_ONCE(!ftrace_start_up);
1735                         hash_disable = false;
1736                 }
1737         }
1738
1739         if (hash_disable)
1740                 ftrace_hash_rec_disable(ops, 1);
1741
1742         if (ops != &global_ops || !global_start_up)
1743                 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
1744
1745         if (!ftrace_start_up)
1746                 command |= FTRACE_DISABLE_CALLS;
1747
1748         if (saved_ftrace_func != ftrace_trace_function) {
1749                 saved_ftrace_func = ftrace_trace_function;
1750                 command |= FTRACE_UPDATE_TRACE_FUNC;
1751         }
1752
1753         if (!command || !ftrace_enabled)
1754                 return;
1755
1756         ftrace_run_update_code(command);
1757 }
1758
1759 static void ftrace_startup_sysctl(void)
1760 {
1761         if (unlikely(ftrace_disabled))
1762                 return;
1763
1764         /* Force update next time */
1765         saved_ftrace_func = NULL;
1766         /* ftrace_start_up is true if we want ftrace running */
1767         if (ftrace_start_up)
1768                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
1769 }
1770
1771 static void ftrace_shutdown_sysctl(void)
1772 {
1773         if (unlikely(ftrace_disabled))
1774                 return;
1775
1776         /* ftrace_start_up is true if ftrace is running */
1777         if (ftrace_start_up)
1778                 ftrace_run_update_code(FTRACE_DISABLE_CALLS);
1779 }
1780
1781 static cycle_t          ftrace_update_time;
1782 static unsigned long    ftrace_update_cnt;
1783 unsigned long           ftrace_update_tot_cnt;
1784
1785 static int ops_traces_mod(struct ftrace_ops *ops)
1786 {
1787         struct ftrace_hash *hash;
1788
1789         hash = ops->filter_hash;
1790         return !!(!hash || !hash->count);
1791 }
1792
1793 static int ftrace_update_code(struct module *mod)
1794 {
1795         struct dyn_ftrace *p;
1796         cycle_t start, stop;
1797         unsigned long ref = 0;
1798
1799         /*
1800          * When adding a module, we need to check if tracers are
1801          * currently enabled and if they are set to trace all functions.
1802          * If they are, we need to enable the module functions as well
1803          * as update the reference counts for those function records.
1804          */
1805         if (mod) {
1806                 struct ftrace_ops *ops;
1807
1808                 for (ops = ftrace_ops_list;
1809                      ops != &ftrace_list_end; ops = ops->next) {
1810                         if (ops->flags & FTRACE_OPS_FL_ENABLED &&
1811                             ops_traces_mod(ops))
1812                                 ref++;
1813                 }
1814         }
1815
1816         start = ftrace_now(raw_smp_processor_id());
1817         ftrace_update_cnt = 0;
1818
1819         while (ftrace_new_addrs) {
1820
1821                 /* If something went wrong, bail without enabling anything */
1822                 if (unlikely(ftrace_disabled))
1823                         return -1;
1824
1825                 p = ftrace_new_addrs;
1826                 ftrace_new_addrs = p->newlist;
1827                 p->flags = ref;
1828
1829                 /*
1830                  * Do the initial record conversion from mcount jump
1831                  * to the NOP instructions.
1832                  */
1833                 if (!ftrace_code_disable(mod, p)) {
1834                         ftrace_free_rec(p);
1835                         /* Game over */
1836                         break;
1837                 }
1838
1839                 ftrace_update_cnt++;
1840
1841                 /*
1842                  * If the tracing is enabled, go ahead and enable the record.
1843                  *
1844                  * The reason not to enable the record immediatelly is the
1845                  * inherent check of ftrace_make_nop/ftrace_make_call for
1846                  * correct previous instructions.  Making first the NOP
1847                  * conversion puts the module to the correct state, thus
1848                  * passing the ftrace_make_call check.
1849                  */
1850                 if (ftrace_start_up && ref) {
1851                         int failed = __ftrace_replace_code(p, 1);
1852                         if (failed) {
1853                                 ftrace_bug(failed, p->ip);
1854                                 ftrace_free_rec(p);
1855                         }
1856                 }
1857         }
1858
1859         stop = ftrace_now(raw_smp_processor_id());
1860         ftrace_update_time = stop - start;
1861         ftrace_update_tot_cnt += ftrace_update_cnt;
1862
1863         return 0;
1864 }
1865
1866 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
1867 {
1868         struct ftrace_page *pg;
1869         int cnt;
1870         int i;
1871
1872         /* allocate a few pages */
1873         ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
1874         if (!ftrace_pages_start)
1875                 return -1;
1876
1877         /*
1878          * Allocate a few more pages.
1879          *
1880          * TODO: have some parser search vmlinux before
1881          *   final linking to find all calls to ftrace.
1882          *   Then we can:
1883          *    a) know how many pages to allocate.
1884          *     and/or
1885          *    b) set up the table then.
1886          *
1887          *  The dynamic code is still necessary for
1888          *  modules.
1889          */
1890
1891         pg = ftrace_pages = ftrace_pages_start;
1892
1893         cnt = num_to_init / ENTRIES_PER_PAGE;
1894         pr_info("ftrace: allocating %ld entries in %d pages\n",
1895                 num_to_init, cnt + 1);
1896
1897         for (i = 0; i < cnt; i++) {
1898                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
1899
1900                 /* If we fail, we'll try later anyway */
1901                 if (!pg->next)
1902                         break;
1903
1904                 pg = pg->next;
1905         }
1906
1907         return 0;
1908 }
1909
1910 enum {
1911         FTRACE_ITER_FILTER      = (1 << 0),
1912         FTRACE_ITER_NOTRACE     = (1 << 1),
1913         FTRACE_ITER_PRINTALL    = (1 << 2),
1914         FTRACE_ITER_HASH        = (1 << 3),
1915         FTRACE_ITER_ENABLED     = (1 << 4),
1916 };
1917
1918 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1919
1920 struct ftrace_iterator {
1921         loff_t                          pos;
1922         loff_t                          func_pos;
1923         struct ftrace_page              *pg;
1924         struct dyn_ftrace               *func;
1925         struct ftrace_func_probe        *probe;
1926         struct trace_parser             parser;
1927         struct ftrace_hash              *hash;
1928         struct ftrace_ops               *ops;
1929         int                             hidx;
1930         int                             idx;
1931         unsigned                        flags;
1932 };
1933
1934 static void *
1935 t_hash_next(struct seq_file *m, loff_t *pos)
1936 {
1937         struct ftrace_iterator *iter = m->private;
1938         struct hlist_node *hnd = NULL;
1939         struct hlist_head *hhd;
1940
1941         (*pos)++;
1942         iter->pos = *pos;
1943
1944         if (iter->probe)
1945                 hnd = &iter->probe->node;
1946  retry:
1947         if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
1948                 return NULL;
1949
1950         hhd = &ftrace_func_hash[iter->hidx];
1951
1952         if (hlist_empty(hhd)) {
1953                 iter->hidx++;
1954                 hnd = NULL;
1955                 goto retry;
1956         }
1957
1958         if (!hnd)
1959                 hnd = hhd->first;
1960         else {
1961                 hnd = hnd->next;
1962                 if (!hnd) {
1963                         iter->hidx++;
1964                         goto retry;
1965                 }
1966         }
1967
1968         if (WARN_ON_ONCE(!hnd))
1969                 return NULL;
1970
1971         iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
1972
1973         return iter;
1974 }
1975
1976 static void *t_hash_start(struct seq_file *m, loff_t *pos)
1977 {
1978         struct ftrace_iterator *iter = m->private;
1979         void *p = NULL;
1980         loff_t l;
1981
1982         if (iter->func_pos > *pos)
1983                 return NULL;
1984
1985         iter->hidx = 0;
1986         for (l = 0; l <= (*pos - iter->func_pos); ) {
1987                 p = t_hash_next(m, &l);
1988                 if (!p)
1989                         break;
1990         }
1991         if (!p)
1992                 return NULL;
1993
1994         /* Only set this if we have an item */
1995         iter->flags |= FTRACE_ITER_HASH;
1996
1997         return iter;
1998 }
1999
2000 static int
2001 t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
2002 {
2003         struct ftrace_func_probe *rec;
2004
2005         rec = iter->probe;
2006         if (WARN_ON_ONCE(!rec))
2007                 return -EIO;
2008
2009         if (rec->ops->print)
2010                 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
2011
2012         seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
2013
2014         if (rec->data)
2015                 seq_printf(m, ":%p", rec->data);
2016         seq_putc(m, '\n');
2017
2018         return 0;
2019 }
2020
2021 static void *
2022 t_next(struct seq_file *m, void *v, loff_t *pos)
2023 {
2024         struct ftrace_iterator *iter = m->private;
2025         struct ftrace_ops *ops = &global_ops;
2026         struct dyn_ftrace *rec = NULL;
2027
2028         if (unlikely(ftrace_disabled))
2029                 return NULL;
2030
2031         if (iter->flags & FTRACE_ITER_HASH)
2032                 return t_hash_next(m, pos);
2033
2034         (*pos)++;
2035         iter->pos = iter->func_pos = *pos;
2036
2037         if (iter->flags & FTRACE_ITER_PRINTALL)
2038                 return t_hash_start(m, pos);
2039
2040  retry:
2041         if (iter->idx >= iter->pg->index) {
2042                 if (iter->pg->next) {
2043                         iter->pg = iter->pg->next;
2044                         iter->idx = 0;
2045                         goto retry;
2046                 }
2047         } else {
2048                 rec = &iter->pg->records[iter->idx++];
2049                 if ((rec->flags & FTRACE_FL_FREE) ||
2050
2051                     ((iter->flags & FTRACE_ITER_FILTER) &&
2052                      !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
2053
2054                     ((iter->flags & FTRACE_ITER_NOTRACE) &&
2055                      !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
2056
2057                     ((iter->flags & FTRACE_ITER_ENABLED) &&
2058                      !(rec->flags & ~FTRACE_FL_MASK))) {
2059
2060                         rec = NULL;
2061                         goto retry;
2062                 }
2063         }
2064
2065         if (!rec)
2066                 return t_hash_start(m, pos);
2067
2068         iter->func = rec;
2069
2070         return iter;
2071 }
2072
2073 static void reset_iter_read(struct ftrace_iterator *iter)
2074 {
2075         iter->pos = 0;
2076         iter->func_pos = 0;
2077         iter->flags &= ~(FTRACE_ITER_PRINTALL & FTRACE_ITER_HASH);
2078 }
2079
2080 static void *t_start(struct seq_file *m, loff_t *pos)
2081 {
2082         struct ftrace_iterator *iter = m->private;
2083         struct ftrace_ops *ops = &global_ops;
2084         void *p = NULL;
2085         loff_t l;
2086
2087         mutex_lock(&ftrace_lock);
2088
2089         if (unlikely(ftrace_disabled))
2090                 return NULL;
2091
2092         /*
2093          * If an lseek was done, then reset and start from beginning.
2094          */
2095         if (*pos < iter->pos)
2096                 reset_iter_read(iter);
2097
2098         /*
2099          * For set_ftrace_filter reading, if we have the filter
2100          * off, we can short cut and just print out that all
2101          * functions are enabled.
2102          */
2103         if (iter->flags & FTRACE_ITER_FILTER && !ops->filter_hash->count) {
2104                 if (*pos > 0)
2105                         return t_hash_start(m, pos);
2106                 iter->flags |= FTRACE_ITER_PRINTALL;
2107                 /* reset in case of seek/pread */
2108                 iter->flags &= ~FTRACE_ITER_HASH;
2109                 return iter;
2110         }
2111
2112         if (iter->flags & FTRACE_ITER_HASH)
2113                 return t_hash_start(m, pos);
2114
2115         /*
2116          * Unfortunately, we need to restart at ftrace_pages_start
2117          * every time we let go of the ftrace_mutex. This is because
2118          * those pointers can change without the lock.
2119          */
2120         iter->pg = ftrace_pages_start;
2121         iter->idx = 0;
2122         for (l = 0; l <= *pos; ) {
2123                 p = t_next(m, p, &l);
2124                 if (!p)
2125                         break;
2126         }
2127
2128         if (!p) {
2129                 if (iter->flags & FTRACE_ITER_FILTER)
2130                         return t_hash_start(m, pos);
2131
2132                 return NULL;
2133         }
2134
2135         return iter;
2136 }
2137
2138 static void t_stop(struct seq_file *m, void *p)
2139 {
2140         mutex_unlock(&ftrace_lock);
2141 }
2142
2143 static int t_show(struct seq_file *m, void *v)
2144 {
2145         struct ftrace_iterator *iter = m->private;
2146         struct dyn_ftrace *rec;
2147
2148         if (iter->flags & FTRACE_ITER_HASH)
2149                 return t_hash_show(m, iter);
2150
2151         if (iter->flags & FTRACE_ITER_PRINTALL) {
2152                 seq_printf(m, "#### all functions enabled ####\n");
2153                 return 0;
2154         }
2155
2156         rec = iter->func;
2157
2158         if (!rec)
2159                 return 0;
2160
2161         seq_printf(m, "%ps", (void *)rec->ip);
2162         if (iter->flags & FTRACE_ITER_ENABLED)
2163                 seq_printf(m, " (%ld)",
2164                            rec->flags & ~FTRACE_FL_MASK);
2165         seq_printf(m, "\n");
2166
2167         return 0;
2168 }
2169
2170 static const struct seq_operations show_ftrace_seq_ops = {
2171         .start = t_start,
2172         .next = t_next,
2173         .stop = t_stop,
2174         .show = t_show,
2175 };
2176
2177 static int
2178 ftrace_avail_open(struct inode *inode, struct file *file)
2179 {
2180         struct ftrace_iterator *iter;
2181         int ret;
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         iter->pg = ftrace_pages_start;
2191
2192         ret = seq_open(file, &show_ftrace_seq_ops);
2193         if (!ret) {
2194                 struct seq_file *m = file->private_data;
2195
2196                 m->private = iter;
2197         } else {
2198                 kfree(iter);
2199         }
2200
2201         return ret;
2202 }
2203
2204 static int
2205 ftrace_enabled_open(struct inode *inode, struct file *file)
2206 {
2207         struct ftrace_iterator *iter;
2208         int ret;
2209
2210         if (unlikely(ftrace_disabled))
2211                 return -ENODEV;
2212
2213         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2214         if (!iter)
2215                 return -ENOMEM;
2216
2217         iter->pg = ftrace_pages_start;
2218         iter->flags = FTRACE_ITER_ENABLED;
2219
2220         ret = seq_open(file, &show_ftrace_seq_ops);
2221         if (!ret) {
2222                 struct seq_file *m = file->private_data;
2223
2224                 m->private = iter;
2225         } else {
2226                 kfree(iter);
2227         }
2228
2229         return ret;
2230 }
2231
2232 static void ftrace_filter_reset(struct ftrace_hash *hash)
2233 {
2234         mutex_lock(&ftrace_lock);
2235         ftrace_hash_clear(hash);
2236         mutex_unlock(&ftrace_lock);
2237 }
2238
2239 static int
2240 ftrace_regex_open(struct ftrace_ops *ops, int flag,
2241                   struct inode *inode, struct file *file)
2242 {
2243         struct ftrace_iterator *iter;
2244         struct ftrace_hash *hash;
2245         int ret = 0;
2246
2247         if (unlikely(ftrace_disabled))
2248                 return -ENODEV;
2249
2250         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2251         if (!iter)
2252                 return -ENOMEM;
2253
2254         if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
2255                 kfree(iter);
2256                 return -ENOMEM;
2257         }
2258
2259         if (flag & FTRACE_ITER_NOTRACE)
2260                 hash = ops->notrace_hash;
2261         else
2262                 hash = ops->filter_hash;
2263
2264         iter->ops = ops;
2265         iter->flags = flag;
2266
2267         if (file->f_mode & FMODE_WRITE) {
2268                 mutex_lock(&ftrace_lock);
2269                 iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
2270                 mutex_unlock(&ftrace_lock);
2271
2272                 if (!iter->hash) {
2273                         trace_parser_put(&iter->parser);
2274                         kfree(iter);
2275                         return -ENOMEM;
2276                 }
2277         }
2278
2279         mutex_lock(&ftrace_regex_lock);
2280
2281         if ((file->f_mode & FMODE_WRITE) &&
2282             (file->f_flags & O_TRUNC))
2283                 ftrace_filter_reset(iter->hash);
2284
2285         if (file->f_mode & FMODE_READ) {
2286                 iter->pg = ftrace_pages_start;
2287
2288                 ret = seq_open(file, &show_ftrace_seq_ops);
2289                 if (!ret) {
2290                         struct seq_file *m = file->private_data;
2291                         m->private = iter;
2292                 } else {
2293                         /* Failed */
2294                         free_ftrace_hash(iter->hash);
2295                         trace_parser_put(&iter->parser);
2296                         kfree(iter);
2297                 }
2298         } else
2299                 file->private_data = iter;
2300         mutex_unlock(&ftrace_regex_lock);
2301
2302         return ret;
2303 }
2304
2305 static int
2306 ftrace_filter_open(struct inode *inode, struct file *file)
2307 {
2308         return ftrace_regex_open(&global_ops, FTRACE_ITER_FILTER,
2309                                  inode, file);
2310 }
2311
2312 static int
2313 ftrace_notrace_open(struct inode *inode, struct file *file)
2314 {
2315         return ftrace_regex_open(&global_ops, FTRACE_ITER_NOTRACE,
2316                                  inode, file);
2317 }
2318
2319 static loff_t
2320 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
2321 {
2322         loff_t ret;
2323
2324         if (file->f_mode & FMODE_READ)
2325                 ret = seq_lseek(file, offset, origin);
2326         else
2327                 file->f_pos = ret = 1;
2328
2329         return ret;
2330 }
2331
2332 static int ftrace_match(char *str, char *regex, int len, int type)
2333 {
2334         int matched = 0;
2335         int slen;
2336
2337         switch (type) {
2338         case MATCH_FULL:
2339                 if (strcmp(str, regex) == 0)
2340                         matched = 1;
2341                 break;
2342         case MATCH_FRONT_ONLY:
2343                 if (strncmp(str, regex, len) == 0)
2344                         matched = 1;
2345                 break;
2346         case MATCH_MIDDLE_ONLY:
2347                 if (strstr(str, regex))
2348                         matched = 1;
2349                 break;
2350         case MATCH_END_ONLY:
2351                 slen = strlen(str);
2352                 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
2353                         matched = 1;
2354                 break;
2355         }
2356
2357         return matched;
2358 }
2359
2360 static int
2361 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
2362 {
2363         struct ftrace_func_entry *entry;
2364         int ret = 0;
2365
2366         entry = ftrace_lookup_ip(hash, rec->ip);
2367         if (not) {
2368                 /* Do nothing if it doesn't exist */
2369                 if (!entry)
2370                         return 0;
2371
2372                 free_hash_entry(hash, entry);
2373         } else {
2374                 /* Do nothing if it exists */
2375                 if (entry)
2376                         return 0;
2377
2378                 ret = add_hash_entry(hash, rec->ip);
2379         }
2380         return ret;
2381 }
2382
2383 static int
2384 ftrace_match_record(struct dyn_ftrace *rec, char *mod,
2385                     char *regex, int len, int type)
2386 {
2387         char str[KSYM_SYMBOL_LEN];
2388         char *modname;
2389
2390         kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
2391
2392         if (mod) {
2393                 /* module lookup requires matching the module */
2394                 if (!modname || strcmp(modname, mod))
2395                         return 0;
2396
2397                 /* blank search means to match all funcs in the mod */
2398                 if (!len)
2399                         return 1;
2400         }
2401
2402         return ftrace_match(str, regex, len, type);
2403 }
2404
2405 static int
2406 match_records(struct ftrace_hash *hash, char *buff,
2407               int len, char *mod, int not)
2408 {
2409         unsigned search_len = 0;
2410         struct ftrace_page *pg;
2411         struct dyn_ftrace *rec;
2412         int type = MATCH_FULL;
2413         char *search = buff;
2414         int found = 0;
2415         int ret;
2416
2417         if (len) {
2418                 type = filter_parse_regex(buff, len, &search, &not);
2419                 search_len = strlen(search);
2420         }
2421
2422         mutex_lock(&ftrace_lock);
2423
2424         if (unlikely(ftrace_disabled))
2425                 goto out_unlock;
2426
2427         do_for_each_ftrace_rec(pg, rec) {
2428
2429                 if (ftrace_match_record(rec, mod, search, search_len, type)) {
2430                         ret = enter_record(hash, rec, not);
2431                         if (ret < 0) {
2432                                 found = ret;
2433                                 goto out_unlock;
2434                         }
2435                         found = 1;
2436                 }
2437         } while_for_each_ftrace_rec();
2438  out_unlock:
2439         mutex_unlock(&ftrace_lock);
2440
2441         return found;
2442 }
2443
2444 static int
2445 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
2446 {
2447         return match_records(hash, buff, len, NULL, 0);
2448 }
2449
2450 static int
2451 ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
2452 {
2453         int not = 0;
2454
2455         /* blank or '*' mean the same */
2456         if (strcmp(buff, "*") == 0)
2457                 buff[0] = 0;
2458
2459         /* handle the case of 'dont filter this module' */
2460         if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
2461                 buff[0] = 0;
2462                 not = 1;
2463         }
2464
2465         return match_records(hash, buff, strlen(buff), mod, not);
2466 }
2467
2468 /*
2469  * We register the module command as a template to show others how
2470  * to register the a command as well.
2471  */
2472
2473 static int
2474 ftrace_mod_callback(struct ftrace_hash *hash,
2475                     char *func, char *cmd, char *param, int enable)
2476 {
2477         char *mod;
2478         int ret = -EINVAL;
2479
2480         /*
2481          * cmd == 'mod' because we only registered this func
2482          * for the 'mod' ftrace_func_command.
2483          * But if you register one func with multiple commands,
2484          * you can tell which command was used by the cmd
2485          * parameter.
2486          */
2487
2488         /* we must have a module name */
2489         if (!param)
2490                 return ret;
2491
2492         mod = strsep(&param, ":");
2493         if (!strlen(mod))
2494                 return ret;
2495
2496         ret = ftrace_match_module_records(hash, func, mod);
2497         if (!ret)
2498                 ret = -EINVAL;
2499         if (ret < 0)
2500                 return ret;
2501
2502         return 0;
2503 }
2504
2505 static struct ftrace_func_command ftrace_mod_cmd = {
2506         .name                   = "mod",
2507         .func                   = ftrace_mod_callback,
2508 };
2509
2510 static int __init ftrace_mod_cmd_init(void)
2511 {
2512         return register_ftrace_command(&ftrace_mod_cmd);
2513 }
2514 device_initcall(ftrace_mod_cmd_init);
2515
2516 static void
2517 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
2518 {
2519         struct ftrace_func_probe *entry;
2520         struct hlist_head *hhd;
2521         struct hlist_node *n;
2522         unsigned long key;
2523
2524         key = hash_long(ip, FTRACE_HASH_BITS);
2525
2526         hhd = &ftrace_func_hash[key];
2527
2528         if (hlist_empty(hhd))
2529                 return;
2530
2531         /*
2532          * Disable preemption for these calls to prevent a RCU grace
2533          * period. This syncs the hash iteration and freeing of items
2534          * on the hash. rcu_read_lock is too dangerous here.
2535          */
2536         preempt_disable_notrace();
2537         hlist_for_each_entry_rcu(entry, n, hhd, node) {
2538                 if (entry->ip == ip)
2539                         entry->ops->func(ip, parent_ip, &entry->data);
2540         }
2541         preempt_enable_notrace();
2542 }
2543
2544 static struct ftrace_ops trace_probe_ops __read_mostly =
2545 {
2546         .func           = function_trace_probe_call,
2547 };
2548
2549 static int ftrace_probe_registered;
2550
2551 static void __enable_ftrace_function_probe(void)
2552 {
2553         int ret;
2554         int i;
2555
2556         if (ftrace_probe_registered)
2557                 return;
2558
2559         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2560                 struct hlist_head *hhd = &ftrace_func_hash[i];
2561                 if (hhd->first)
2562                         break;
2563         }
2564         /* Nothing registered? */
2565         if (i == FTRACE_FUNC_HASHSIZE)
2566                 return;
2567
2568         ret = __register_ftrace_function(&trace_probe_ops);
2569         if (!ret)
2570                 ret = ftrace_startup(&trace_probe_ops, 0);
2571
2572         ftrace_probe_registered = 1;
2573 }
2574
2575 static void __disable_ftrace_function_probe(void)
2576 {
2577         int ret;
2578         int i;
2579
2580         if (!ftrace_probe_registered)
2581                 return;
2582
2583         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2584                 struct hlist_head *hhd = &ftrace_func_hash[i];
2585                 if (hhd->first)
2586                         return;
2587         }
2588
2589         /* no more funcs left */
2590         ret = __unregister_ftrace_function(&trace_probe_ops);
2591         if (!ret)
2592                 ftrace_shutdown(&trace_probe_ops, 0);
2593
2594         ftrace_probe_registered = 0;
2595 }
2596
2597
2598 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
2599 {
2600         struct ftrace_func_probe *entry =
2601                 container_of(rhp, struct ftrace_func_probe, rcu);
2602
2603         if (entry->ops->free)
2604                 entry->ops->free(&entry->data);
2605         kfree(entry);
2606 }
2607
2608
2609 int
2610 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2611                               void *data)
2612 {
2613         struct ftrace_func_probe *entry;
2614         struct ftrace_page *pg;
2615         struct dyn_ftrace *rec;
2616         int type, len, not;
2617         unsigned long key;
2618         int count = 0;
2619         char *search;
2620
2621         type = filter_parse_regex(glob, strlen(glob), &search, &not);
2622         len = strlen(search);
2623
2624         /* we do not support '!' for function probes */
2625         if (WARN_ON(not))
2626                 return -EINVAL;
2627
2628         mutex_lock(&ftrace_lock);
2629
2630         if (unlikely(ftrace_disabled))
2631                 goto out_unlock;
2632
2633         do_for_each_ftrace_rec(pg, rec) {
2634
2635                 if (!ftrace_match_record(rec, NULL, search, len, type))
2636                         continue;
2637
2638                 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2639                 if (!entry) {
2640                         /* If we did not process any, then return error */
2641                         if (!count)
2642                                 count = -ENOMEM;
2643                         goto out_unlock;
2644                 }
2645
2646                 count++;
2647
2648                 entry->data = data;
2649
2650                 /*
2651                  * The caller might want to do something special
2652                  * for each function we find. We call the callback
2653                  * to give the caller an opportunity to do so.
2654                  */
2655                 if (ops->callback) {
2656                         if (ops->callback(rec->ip, &entry->data) < 0) {
2657                                 /* caller does not like this func */
2658                                 kfree(entry);
2659                                 continue;
2660                         }
2661                 }
2662
2663                 entry->ops = ops;
2664                 entry->ip = rec->ip;
2665
2666                 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2667                 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2668
2669         } while_for_each_ftrace_rec();
2670         __enable_ftrace_function_probe();
2671
2672  out_unlock:
2673         mutex_unlock(&ftrace_lock);
2674
2675         return count;
2676 }
2677
2678 enum {
2679         PROBE_TEST_FUNC         = 1,
2680         PROBE_TEST_DATA         = 2
2681 };
2682
2683 static void
2684 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2685                                   void *data, int flags)
2686 {
2687         struct ftrace_func_probe *entry;
2688         struct hlist_node *n, *tmp;
2689         char str[KSYM_SYMBOL_LEN];
2690         int type = MATCH_FULL;
2691         int i, len = 0;
2692         char *search;
2693
2694         if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
2695                 glob = NULL;
2696         else if (glob) {
2697                 int not;
2698
2699                 type = filter_parse_regex(glob, strlen(glob), &search, &not);
2700                 len = strlen(search);
2701
2702                 /* we do not support '!' for function probes */
2703                 if (WARN_ON(not))
2704                         return;
2705         }
2706
2707         mutex_lock(&ftrace_lock);
2708         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2709                 struct hlist_head *hhd = &ftrace_func_hash[i];
2710
2711                 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
2712
2713                         /* break up if statements for readability */
2714                         if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2715                                 continue;
2716
2717                         if ((flags & PROBE_TEST_DATA) && entry->data != data)
2718                                 continue;
2719
2720                         /* do this last, since it is the most expensive */
2721                         if (glob) {
2722                                 kallsyms_lookup(entry->ip, NULL, NULL,
2723                                                 NULL, str);
2724                                 if (!ftrace_match(str, glob, len, type))
2725                                         continue;
2726                         }
2727
2728                         hlist_del(&entry->node);
2729                         call_rcu(&entry->rcu, ftrace_free_entry_rcu);
2730                 }
2731         }
2732         __disable_ftrace_function_probe();
2733         mutex_unlock(&ftrace_lock);
2734 }
2735
2736 void
2737 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2738                                 void *data)
2739 {
2740         __unregister_ftrace_function_probe(glob, ops, data,
2741                                           PROBE_TEST_FUNC | PROBE_TEST_DATA);
2742 }
2743
2744 void
2745 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
2746 {
2747         __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
2748 }
2749
2750 void unregister_ftrace_function_probe_all(char *glob)
2751 {
2752         __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
2753 }
2754
2755 static LIST_HEAD(ftrace_commands);
2756 static DEFINE_MUTEX(ftrace_cmd_mutex);
2757
2758 int register_ftrace_command(struct ftrace_func_command *cmd)
2759 {
2760         struct ftrace_func_command *p;
2761         int ret = 0;
2762
2763         mutex_lock(&ftrace_cmd_mutex);
2764         list_for_each_entry(p, &ftrace_commands, list) {
2765                 if (strcmp(cmd->name, p->name) == 0) {
2766                         ret = -EBUSY;
2767                         goto out_unlock;
2768                 }
2769         }
2770         list_add(&cmd->list, &ftrace_commands);
2771  out_unlock:
2772         mutex_unlock(&ftrace_cmd_mutex);
2773
2774         return ret;
2775 }
2776
2777 int unregister_ftrace_command(struct ftrace_func_command *cmd)
2778 {
2779         struct ftrace_func_command *p, *n;
2780         int ret = -ENODEV;
2781
2782         mutex_lock(&ftrace_cmd_mutex);
2783         list_for_each_entry_safe(p, n, &ftrace_commands, list) {
2784                 if (strcmp(cmd->name, p->name) == 0) {
2785                         ret = 0;
2786                         list_del_init(&p->list);
2787                         goto out_unlock;
2788                 }
2789         }
2790  out_unlock:
2791         mutex_unlock(&ftrace_cmd_mutex);
2792
2793         return ret;
2794 }
2795
2796 static int ftrace_process_regex(struct ftrace_hash *hash,
2797                                 char *buff, int len, int enable)
2798 {
2799         char *func, *command, *next = buff;
2800         struct ftrace_func_command *p;
2801         int ret = -EINVAL;
2802
2803         func = strsep(&next, ":");
2804
2805         if (!next) {
2806                 ret = ftrace_match_records(hash, func, len);
2807                 if (!ret)
2808                         ret = -EINVAL;
2809                 if (ret < 0)
2810                         return ret;
2811                 return 0;
2812         }
2813
2814         /* command found */
2815
2816         command = strsep(&next, ":");
2817
2818         mutex_lock(&ftrace_cmd_mutex);
2819         list_for_each_entry(p, &ftrace_commands, list) {
2820                 if (strcmp(p->name, command) == 0) {
2821                         ret = p->func(hash, func, command, next, enable);
2822                         goto out_unlock;
2823                 }
2824         }
2825  out_unlock:
2826         mutex_unlock(&ftrace_cmd_mutex);
2827
2828         return ret;
2829 }
2830
2831 static ssize_t
2832 ftrace_regex_write(struct file *file, const char __user *ubuf,
2833                    size_t cnt, loff_t *ppos, int enable)
2834 {
2835         struct ftrace_iterator *iter;
2836         struct trace_parser *parser;
2837         ssize_t ret, read;
2838
2839         if (!cnt)
2840                 return 0;
2841
2842         mutex_lock(&ftrace_regex_lock);
2843
2844         ret = -ENODEV;
2845         if (unlikely(ftrace_disabled))
2846                 goto out_unlock;
2847
2848         if (file->f_mode & FMODE_READ) {
2849                 struct seq_file *m = file->private_data;
2850                 iter = m->private;
2851         } else
2852                 iter = file->private_data;
2853
2854         parser = &iter->parser;
2855         read = trace_get_user(parser, ubuf, cnt, ppos);
2856
2857         if (read >= 0 && trace_parser_loaded(parser) &&
2858             !trace_parser_cont(parser)) {
2859                 ret = ftrace_process_regex(iter->hash, parser->buffer,
2860                                            parser->idx, enable);
2861                 trace_parser_clear(parser);
2862                 if (ret)
2863                         goto out_unlock;
2864         }
2865
2866         ret = read;
2867 out_unlock:
2868         mutex_unlock(&ftrace_regex_lock);
2869
2870         return ret;
2871 }
2872
2873 static ssize_t
2874 ftrace_filter_write(struct file *file, const char __user *ubuf,
2875                     size_t cnt, loff_t *ppos)
2876 {
2877         return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
2878 }
2879
2880 static ssize_t
2881 ftrace_notrace_write(struct file *file, const char __user *ubuf,
2882                      size_t cnt, loff_t *ppos)
2883 {
2884         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
2885 }
2886
2887 static int
2888 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
2889                  int reset, int enable)
2890 {
2891         struct ftrace_hash **orig_hash;
2892         struct ftrace_hash *hash;
2893         int ret;
2894
2895         /* All global ops uses the global ops filters */
2896         if (ops->flags & FTRACE_OPS_FL_GLOBAL)
2897                 ops = &global_ops;
2898
2899         if (unlikely(ftrace_disabled))
2900                 return -ENODEV;
2901
2902         if (enable)
2903                 orig_hash = &ops->filter_hash;
2904         else
2905                 orig_hash = &ops->notrace_hash;
2906
2907         hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
2908         if (!hash)
2909                 return -ENOMEM;
2910
2911         mutex_lock(&ftrace_regex_lock);
2912         if (reset)
2913                 ftrace_filter_reset(hash);
2914         if (buf)
2915                 ftrace_match_records(hash, buf, len);
2916
2917         mutex_lock(&ftrace_lock);
2918         ret = ftrace_hash_move(ops, enable, orig_hash, hash);
2919         if (!ret && ops->flags & FTRACE_OPS_FL_ENABLED
2920             && ftrace_enabled)
2921                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
2922
2923         mutex_unlock(&ftrace_lock);
2924
2925         mutex_unlock(&ftrace_regex_lock);
2926
2927         free_ftrace_hash(hash);
2928         return ret;
2929 }
2930
2931 /**
2932  * ftrace_set_filter - set a function to filter on in ftrace
2933  * @ops - the ops to set the filter with
2934  * @buf - the string that holds the function filter text.
2935  * @len - the length of the string.
2936  * @reset - non zero to reset all filters before applying this filter.
2937  *
2938  * Filters denote which functions should be enabled when tracing is enabled.
2939  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2940  */
2941 void ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
2942                        int len, int reset)
2943 {
2944         ftrace_set_regex(ops, buf, len, reset, 1);
2945 }
2946 EXPORT_SYMBOL_GPL(ftrace_set_filter);
2947
2948 /**
2949  * ftrace_set_notrace - set a function to not trace in ftrace
2950  * @ops - the ops to set the notrace filter with
2951  * @buf - the string that holds the function notrace text.
2952  * @len - the length of the string.
2953  * @reset - non zero to reset all filters before applying this filter.
2954  *
2955  * Notrace Filters denote which functions should not be enabled when tracing
2956  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2957  * for tracing.
2958  */
2959 void ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
2960                         int len, int reset)
2961 {
2962         ftrace_set_regex(ops, buf, len, reset, 0);
2963 }
2964 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
2965 /**
2966  * ftrace_set_filter - set a function to filter on in ftrace
2967  * @ops - the ops to set the filter with
2968  * @buf - the string that holds the function filter text.
2969  * @len - the length of the string.
2970  * @reset - non zero to reset all filters before applying this filter.
2971  *
2972  * Filters denote which functions should be enabled when tracing is enabled.
2973  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2974  */
2975 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
2976 {
2977         ftrace_set_regex(&global_ops, buf, len, reset, 1);
2978 }
2979 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
2980
2981 /**
2982  * ftrace_set_notrace - set a function to not trace in ftrace
2983  * @ops - the ops to set the notrace filter with
2984  * @buf - the string that holds the function notrace text.
2985  * @len - the length of the string.
2986  * @reset - non zero to reset all filters before applying this filter.
2987  *
2988  * Notrace Filters denote which functions should not be enabled when tracing
2989  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2990  * for tracing.
2991  */
2992 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
2993 {
2994         ftrace_set_regex(&global_ops, buf, len, reset, 0);
2995 }
2996 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
2997
2998 /*
2999  * command line interface to allow users to set filters on boot up.
3000  */
3001 #define FTRACE_FILTER_SIZE              COMMAND_LINE_SIZE
3002 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
3003 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
3004
3005 static int __init set_ftrace_notrace(char *str)
3006 {
3007         strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
3008         return 1;
3009 }
3010 __setup("ftrace_notrace=", set_ftrace_notrace);
3011
3012 static int __init set_ftrace_filter(char *str)
3013 {
3014         strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
3015         return 1;
3016 }
3017 __setup("ftrace_filter=", set_ftrace_filter);
3018
3019 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3020 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
3021 static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
3022
3023 static int __init set_graph_function(char *str)
3024 {
3025         strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
3026         return 1;
3027 }
3028 __setup("ftrace_graph_filter=", set_graph_function);
3029
3030 static void __init set_ftrace_early_graph(char *buf)
3031 {
3032         int ret;
3033         char *func;
3034
3035         while (buf) {
3036                 func = strsep(&buf, ",");
3037                 /* we allow only one expression at a time */
3038                 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3039                                       func);
3040                 if (ret)
3041                         printk(KERN_DEBUG "ftrace: function %s not "
3042                                           "traceable\n", func);
3043         }
3044 }
3045 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3046
3047 static void __init
3048 set_ftrace_early_filter(struct ftrace_ops *ops, char *buf, int enable)
3049 {
3050         char *func;
3051
3052         while (buf) {
3053                 func = strsep(&buf, ",");
3054                 ftrace_set_regex(ops, func, strlen(func), 0, enable);
3055         }
3056 }
3057
3058 static void __init set_ftrace_early_filters(void)
3059 {
3060         if (ftrace_filter_buf[0])
3061                 set_ftrace_early_filter(&global_ops, ftrace_filter_buf, 1);
3062         if (ftrace_notrace_buf[0])
3063                 set_ftrace_early_filter(&global_ops, ftrace_notrace_buf, 0);
3064 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3065         if (ftrace_graph_buf[0])
3066                 set_ftrace_early_graph(ftrace_graph_buf);
3067 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3068 }
3069
3070 static int
3071 ftrace_regex_release(struct inode *inode, struct file *file)
3072 {
3073         struct seq_file *m = (struct seq_file *)file->private_data;
3074         struct ftrace_iterator *iter;
3075         struct ftrace_hash **orig_hash;
3076         struct trace_parser *parser;
3077         int filter_hash;
3078         int ret;
3079
3080         mutex_lock(&ftrace_regex_lock);
3081         if (file->f_mode & FMODE_READ) {
3082                 iter = m->private;
3083
3084                 seq_release(inode, file);
3085         } else
3086                 iter = file->private_data;
3087
3088         parser = &iter->parser;
3089         if (trace_parser_loaded(parser)) {
3090                 parser->buffer[parser->idx] = 0;
3091                 ftrace_match_records(iter->hash, parser->buffer, parser->idx);
3092         }
3093
3094         trace_parser_put(parser);
3095
3096         if (file->f_mode & FMODE_WRITE) {
3097                 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
3098
3099                 if (filter_hash)
3100                         orig_hash = &iter->ops->filter_hash;
3101                 else
3102                         orig_hash = &iter->ops->notrace_hash;
3103
3104                 mutex_lock(&ftrace_lock);
3105                 ret = ftrace_hash_move(iter->ops, filter_hash,
3106                                        orig_hash, iter->hash);
3107                 if (!ret && (iter->ops->flags & FTRACE_OPS_FL_ENABLED)
3108                     && ftrace_enabled)
3109                         ftrace_run_update_code(FTRACE_ENABLE_CALLS);
3110
3111                 mutex_unlock(&ftrace_lock);
3112         }
3113         free_ftrace_hash(iter->hash);
3114         kfree(iter);
3115
3116         mutex_unlock(&ftrace_regex_lock);
3117         return 0;
3118 }
3119
3120 static const struct file_operations ftrace_avail_fops = {
3121         .open = ftrace_avail_open,
3122         .read = seq_read,
3123         .llseek = seq_lseek,
3124         .release = seq_release_private,
3125 };
3126
3127 static const struct file_operations ftrace_enabled_fops = {
3128         .open = ftrace_enabled_open,
3129         .read = seq_read,
3130         .llseek = seq_lseek,
3131         .release = seq_release_private,
3132 };
3133
3134 static const struct file_operations ftrace_filter_fops = {
3135         .open = ftrace_filter_open,
3136         .read = seq_read,
3137         .write = ftrace_filter_write,
3138         .llseek = ftrace_regex_lseek,
3139         .release = ftrace_regex_release,
3140 };
3141
3142 static const struct file_operations ftrace_notrace_fops = {
3143         .open = ftrace_notrace_open,
3144         .read = seq_read,
3145         .write = ftrace_notrace_write,
3146         .llseek = ftrace_regex_lseek,
3147         .release = ftrace_regex_release,
3148 };
3149
3150 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3151
3152 static DEFINE_MUTEX(graph_lock);
3153
3154 int ftrace_graph_count;
3155 int ftrace_graph_filter_enabled;
3156 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
3157
3158 static void *
3159 __g_next(struct seq_file *m, loff_t *pos)
3160 {
3161         if (*pos >= ftrace_graph_count)
3162                 return NULL;
3163         return &ftrace_graph_funcs[*pos];
3164 }
3165
3166 static void *
3167 g_next(struct seq_file *m, void *v, loff_t *pos)
3168 {
3169         (*pos)++;
3170         return __g_next(m, pos);
3171 }
3172
3173 static void *g_start(struct seq_file *m, loff_t *pos)
3174 {
3175         mutex_lock(&graph_lock);
3176
3177         /* Nothing, tell g_show to print all functions are enabled */
3178         if (!ftrace_graph_filter_enabled && !*pos)
3179                 return (void *)1;
3180
3181         return __g_next(m, pos);
3182 }
3183
3184 static void g_stop(struct seq_file *m, void *p)
3185 {
3186         mutex_unlock(&graph_lock);
3187 }
3188
3189 static int g_show(struct seq_file *m, void *v)
3190 {
3191         unsigned long *ptr = v;
3192
3193         if (!ptr)
3194                 return 0;
3195
3196         if (ptr == (unsigned long *)1) {
3197                 seq_printf(m, "#### all functions enabled ####\n");
3198                 return 0;
3199         }
3200
3201         seq_printf(m, "%ps\n", (void *)*ptr);
3202
3203         return 0;
3204 }
3205
3206 static const struct seq_operations ftrace_graph_seq_ops = {
3207         .start = g_start,
3208         .next = g_next,
3209         .stop = g_stop,
3210         .show = g_show,
3211 };
3212
3213 static int
3214 ftrace_graph_open(struct inode *inode, struct file *file)
3215 {
3216         int ret = 0;
3217
3218         if (unlikely(ftrace_disabled))
3219                 return -ENODEV;
3220
3221         mutex_lock(&graph_lock);
3222         if ((file->f_mode & FMODE_WRITE) &&
3223             (file->f_flags & O_TRUNC)) {
3224                 ftrace_graph_filter_enabled = 0;
3225                 ftrace_graph_count = 0;
3226                 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
3227         }
3228         mutex_unlock(&graph_lock);
3229
3230         if (file->f_mode & FMODE_READ)
3231                 ret = seq_open(file, &ftrace_graph_seq_ops);
3232
3233         return ret;
3234 }
3235
3236 static int
3237 ftrace_graph_release(struct inode *inode, struct file *file)
3238 {
3239         if (file->f_mode & FMODE_READ)
3240                 seq_release(inode, file);
3241         return 0;
3242 }
3243
3244 static int
3245 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
3246 {
3247         struct dyn_ftrace *rec;
3248         struct ftrace_page *pg;
3249         int search_len;
3250         int fail = 1;
3251         int type, not;
3252         char *search;
3253         bool exists;
3254         int i;
3255
3256         /* decode regex */
3257         type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
3258         if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
3259                 return -EBUSY;
3260
3261         search_len = strlen(search);
3262
3263         mutex_lock(&ftrace_lock);
3264
3265         if (unlikely(ftrace_disabled)) {
3266                 mutex_unlock(&ftrace_lock);
3267                 return -ENODEV;
3268         }
3269
3270         do_for_each_ftrace_rec(pg, rec) {
3271
3272                 if (rec->flags & FTRACE_FL_FREE)
3273                         continue;
3274
3275                 if (ftrace_match_record(rec, NULL, search, search_len, type)) {
3276                         /* if it is in the array */
3277                         exists = false;
3278                         for (i = 0; i < *idx; i++) {
3279                                 if (array[i] == rec->ip) {
3280                                         exists = true;
3281                                         break;
3282                                 }
3283                         }
3284
3285                         if (!not) {
3286                                 fail = 0;
3287                                 if (!exists) {
3288                                         array[(*idx)++] = rec->ip;
3289                                         if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
3290                                                 goto out;
3291                                 }
3292                         } else {
3293                                 if (exists) {
3294                                         array[i] = array[--(*idx)];
3295                                         array[*idx] = 0;
3296                                         fail = 0;
3297                                 }
3298                         }
3299                 }
3300         } while_for_each_ftrace_rec();
3301 out:
3302         mutex_unlock(&ftrace_lock);
3303
3304         if (fail)
3305                 return -EINVAL;
3306
3307         ftrace_graph_filter_enabled = 1;
3308         return 0;
3309 }
3310
3311 static ssize_t
3312 ftrace_graph_write(struct file *file, const char __user *ubuf,
3313                    size_t cnt, loff_t *ppos)
3314 {
3315         struct trace_parser parser;
3316         ssize_t read, ret;
3317
3318         if (!cnt)
3319                 return 0;
3320
3321         mutex_lock(&graph_lock);
3322
3323         if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
3324                 ret = -ENOMEM;
3325                 goto out_unlock;
3326         }
3327
3328         read = trace_get_user(&parser, ubuf, cnt, ppos);
3329
3330         if (read >= 0 && trace_parser_loaded((&parser))) {
3331                 parser.buffer[parser.idx] = 0;
3332
3333                 /* we allow only one expression at a time */
3334                 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3335                                         parser.buffer);
3336                 if (ret)
3337                         goto out_free;
3338         }
3339
3340         ret = read;
3341
3342 out_free:
3343         trace_parser_put(&parser);
3344 out_unlock:
3345         mutex_unlock(&graph_lock);
3346
3347         return ret;
3348 }
3349
3350 static const struct file_operations ftrace_graph_fops = {
3351         .open           = ftrace_graph_open,
3352         .read           = seq_read,
3353         .write          = ftrace_graph_write,
3354         .release        = ftrace_graph_release,
3355         .llseek         = seq_lseek,
3356 };
3357 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3358
3359 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
3360 {
3361
3362         trace_create_file("available_filter_functions", 0444,
3363                         d_tracer, NULL, &ftrace_avail_fops);
3364
3365         trace_create_file("enabled_functions", 0444,
3366                         d_tracer, NULL, &ftrace_enabled_fops);
3367
3368         trace_create_file("set_ftrace_filter", 0644, d_tracer,
3369                         NULL, &ftrace_filter_fops);
3370
3371         trace_create_file("set_ftrace_notrace", 0644, d_tracer,
3372                                     NULL, &ftrace_notrace_fops);
3373
3374 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3375         trace_create_file("set_graph_function", 0444, d_tracer,
3376                                     NULL,
3377                                     &ftrace_graph_fops);
3378 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3379
3380         return 0;
3381 }
3382
3383 static int ftrace_process_locs(struct module *mod,
3384                                unsigned long *start,
3385                                unsigned long *end)
3386 {
3387         unsigned long *p;
3388         unsigned long addr;
3389         unsigned long flags = 0; /* Shut up gcc */
3390
3391         mutex_lock(&ftrace_lock);
3392         p = start;
3393         while (p < end) {
3394                 addr = ftrace_call_adjust(*p++);
3395                 /*
3396                  * Some architecture linkers will pad between
3397                  * the different mcount_loc sections of different
3398                  * object files to satisfy alignments.
3399                  * Skip any NULL pointers.
3400                  */
3401                 if (!addr)
3402                         continue;
3403                 ftrace_record_ip(addr);
3404         }
3405
3406         /*
3407          * We only need to disable interrupts on start up
3408          * because we are modifying code that an interrupt
3409          * may execute, and the modification is not atomic.
3410          * But for modules, nothing runs the code we modify
3411          * until we are finished with it, and there's no
3412          * reason to cause large interrupt latencies while we do it.
3413          */
3414         if (!mod)
3415                 local_irq_save(flags);
3416         ftrace_update_code(mod);
3417         if (!mod)
3418                 local_irq_restore(flags);
3419         mutex_unlock(&ftrace_lock);
3420
3421         return 0;
3422 }
3423
3424 #ifdef CONFIG_MODULES
3425 void ftrace_release_mod(struct module *mod)
3426 {
3427         struct dyn_ftrace *rec;
3428         struct ftrace_page *pg;
3429
3430         mutex_lock(&ftrace_lock);
3431
3432         if (ftrace_disabled)
3433                 goto out_unlock;
3434
3435         do_for_each_ftrace_rec(pg, rec) {
3436                 if (within_module_core(rec->ip, mod)) {
3437                         /*
3438                          * rec->ip is changed in ftrace_free_rec()
3439                          * It should not between s and e if record was freed.
3440                          */
3441                         FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
3442                         ftrace_free_rec(rec);
3443                 }
3444         } while_for_each_ftrace_rec();
3445  out_unlock:
3446         mutex_unlock(&ftrace_lock);
3447 }
3448
3449 static void ftrace_init_module(struct module *mod,
3450                                unsigned long *start, unsigned long *end)
3451 {
3452         if (ftrace_disabled || start == end)
3453                 return;
3454         ftrace_process_locs(mod, start, end);
3455 }
3456
3457 static int ftrace_module_notify(struct notifier_block *self,
3458                                 unsigned long val, void *data)
3459 {
3460         struct module *mod = data;
3461
3462         switch (val) {
3463         case MODULE_STATE_COMING:
3464                 ftrace_init_module(mod, mod->ftrace_callsites,
3465                                    mod->ftrace_callsites +
3466                                    mod->num_ftrace_callsites);
3467                 break;
3468         case MODULE_STATE_GOING:
3469                 ftrace_release_mod(mod);
3470                 break;
3471         }
3472
3473         return 0;
3474 }
3475 #else
3476 static int ftrace_module_notify(struct notifier_block *self,
3477                                 unsigned long val, void *data)
3478 {
3479         return 0;
3480 }
3481 #endif /* CONFIG_MODULES */
3482
3483 struct notifier_block ftrace_module_nb = {
3484         .notifier_call = ftrace_module_notify,
3485         .priority = 0,
3486 };
3487
3488 extern unsigned long __start_mcount_loc[];
3489 extern unsigned long __stop_mcount_loc[];
3490
3491 void __init ftrace_init(void)
3492 {
3493         unsigned long count, addr, flags;
3494         int ret;
3495
3496         /* Keep the ftrace pointer to the stub */
3497         addr = (unsigned long)ftrace_stub;
3498
3499         local_irq_save(flags);
3500         ftrace_dyn_arch_init(&addr);
3501         local_irq_restore(flags);
3502
3503         /* ftrace_dyn_arch_init places the return code in addr */
3504         if (addr)
3505                 goto failed;
3506
3507         count = __stop_mcount_loc - __start_mcount_loc;
3508
3509         ret = ftrace_dyn_table_alloc(count);
3510         if (ret)
3511                 goto failed;
3512
3513         last_ftrace_enabled = ftrace_enabled = 1;
3514
3515         ret = ftrace_process_locs(NULL,
3516                                   __start_mcount_loc,
3517                                   __stop_mcount_loc);
3518
3519         ret = register_module_notifier(&ftrace_module_nb);
3520         if (ret)
3521                 pr_warning("Failed to register trace ftrace module notifier\n");
3522
3523         set_ftrace_early_filters();
3524
3525         return;
3526  failed:
3527         ftrace_disabled = 1;
3528 }
3529
3530 #else
3531
3532 static struct ftrace_ops global_ops = {
3533         .func                   = ftrace_stub,
3534 };
3535
3536 static int __init ftrace_nodyn_init(void)
3537 {
3538         ftrace_enabled = 1;
3539         return 0;
3540 }
3541 device_initcall(ftrace_nodyn_init);
3542
3543 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
3544 static inline void ftrace_startup_enable(int command) { }
3545 /* Keep as macros so we do not need to define the commands */
3546 # define ftrace_startup(ops, command)                   \
3547         ({                                              \
3548                 (ops)->flags |= FTRACE_OPS_FL_ENABLED;  \
3549                 0;                                      \
3550         })
3551 # define ftrace_shutdown(ops, command)  do { } while (0)
3552 # define ftrace_startup_sysctl()        do { } while (0)
3553 # define ftrace_shutdown_sysctl()       do { } while (0)
3554
3555 static inline int
3556 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
3557 {
3558         return 1;
3559 }
3560
3561 #endif /* CONFIG_DYNAMIC_FTRACE */
3562
3563 static void
3564 ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
3565 {
3566         struct ftrace_ops *op;
3567
3568         if (unlikely(trace_recursion_test(TRACE_INTERNAL_BIT)))
3569                 return;
3570
3571         trace_recursion_set(TRACE_INTERNAL_BIT);
3572         /*
3573          * Some of the ops may be dynamically allocated,
3574          * they must be freed after a synchronize_sched().
3575          */
3576         preempt_disable_notrace();
3577         op = rcu_dereference_raw(ftrace_ops_list);
3578         while (op != &ftrace_list_end) {
3579                 if (ftrace_ops_test(op, ip))
3580                         op->func(ip, parent_ip);
3581                 op = rcu_dereference_raw(op->next);
3582         };
3583         preempt_enable_notrace();
3584         trace_recursion_clear(TRACE_INTERNAL_BIT);
3585 }
3586
3587 static void clear_ftrace_swapper(void)
3588 {
3589         struct task_struct *p;
3590         int cpu;
3591
3592         get_online_cpus();
3593         for_each_online_cpu(cpu) {
3594                 p = idle_task(cpu);
3595                 clear_tsk_trace_trace(p);
3596         }
3597         put_online_cpus();
3598 }
3599
3600 static void set_ftrace_swapper(void)
3601 {
3602         struct task_struct *p;
3603         int cpu;
3604
3605         get_online_cpus();
3606         for_each_online_cpu(cpu) {
3607                 p = idle_task(cpu);
3608                 set_tsk_trace_trace(p);
3609         }
3610         put_online_cpus();
3611 }
3612
3613 static void clear_ftrace_pid(struct pid *pid)
3614 {
3615         struct task_struct *p;
3616
3617         rcu_read_lock();
3618         do_each_pid_task(pid, PIDTYPE_PID, p) {
3619                 clear_tsk_trace_trace(p);
3620         } while_each_pid_task(pid, PIDTYPE_PID, p);
3621         rcu_read_unlock();
3622
3623         put_pid(pid);
3624 }
3625
3626 static void set_ftrace_pid(struct pid *pid)
3627 {
3628         struct task_struct *p;
3629
3630         rcu_read_lock();
3631         do_each_pid_task(pid, PIDTYPE_PID, p) {
3632                 set_tsk_trace_trace(p);
3633         } while_each_pid_task(pid, PIDTYPE_PID, p);
3634         rcu_read_unlock();
3635 }
3636
3637 static void clear_ftrace_pid_task(struct pid *pid)
3638 {
3639         if (pid == ftrace_swapper_pid)
3640                 clear_ftrace_swapper();
3641         else
3642                 clear_ftrace_pid(pid);
3643 }
3644
3645 static void set_ftrace_pid_task(struct pid *pid)
3646 {
3647         if (pid == ftrace_swapper_pid)
3648                 set_ftrace_swapper();
3649         else
3650                 set_ftrace_pid(pid);
3651 }
3652
3653 static int ftrace_pid_add(int p)
3654 {
3655         struct pid *pid;
3656         struct ftrace_pid *fpid;
3657         int ret = -EINVAL;
3658
3659         mutex_lock(&ftrace_lock);
3660
3661         if (!p)
3662                 pid = ftrace_swapper_pid;
3663         else
3664                 pid = find_get_pid(p);
3665
3666         if (!pid)
3667                 goto out;
3668
3669         ret = 0;
3670
3671         list_for_each_entry(fpid, &ftrace_pids, list)
3672                 if (fpid->pid == pid)
3673                         goto out_put;
3674
3675         ret = -ENOMEM;
3676
3677         fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
3678         if (!fpid)
3679                 goto out_put;
3680
3681         list_add(&fpid->list, &ftrace_pids);
3682         fpid->pid = pid;
3683
3684         set_ftrace_pid_task(pid);
3685
3686         ftrace_update_pid_func();
3687         ftrace_startup_enable(0);
3688
3689         mutex_unlock(&ftrace_lock);
3690         return 0;
3691
3692 out_put:
3693         if (pid != ftrace_swapper_pid)
3694                 put_pid(pid);
3695
3696 out:
3697         mutex_unlock(&ftrace_lock);
3698         return ret;
3699 }
3700
3701 static void ftrace_pid_reset(void)
3702 {
3703         struct ftrace_pid *fpid, *safe;
3704
3705         mutex_lock(&ftrace_lock);
3706         list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
3707                 struct pid *pid = fpid->pid;
3708
3709                 clear_ftrace_pid_task(pid);
3710
3711                 list_del(&fpid->list);
3712                 kfree(fpid);
3713         }
3714
3715         ftrace_update_pid_func();
3716         ftrace_startup_enable(0);
3717
3718         mutex_unlock(&ftrace_lock);
3719 }
3720
3721 static void *fpid_start(struct seq_file *m, loff_t *pos)
3722 {
3723         mutex_lock(&ftrace_lock);
3724
3725         if (list_empty(&ftrace_pids) && (!*pos))
3726                 return (void *) 1;
3727
3728         return seq_list_start(&ftrace_pids, *pos);
3729 }
3730
3731 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
3732 {
3733         if (v == (void *)1)
3734                 return NULL;
3735
3736         return seq_list_next(v, &ftrace_pids, pos);
3737 }
3738
3739 static void fpid_stop(struct seq_file *m, void *p)
3740 {
3741         mutex_unlock(&ftrace_lock);
3742 }
3743
3744 static int fpid_show(struct seq_file *m, void *v)
3745 {
3746         const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
3747
3748         if (v == (void *)1) {
3749                 seq_printf(m, "no pid\n");
3750                 return 0;
3751         }
3752
3753         if (fpid->pid == ftrace_swapper_pid)
3754                 seq_printf(m, "swapper tasks\n");
3755         else
3756                 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
3757
3758         return 0;
3759 }
3760
3761 static const struct seq_operations ftrace_pid_sops = {
3762         .start = fpid_start,
3763         .next = fpid_next,
3764         .stop = fpid_stop,
3765         .show = fpid_show,
3766 };
3767
3768 static int
3769 ftrace_pid_open(struct inode *inode, struct file *file)
3770 {
3771         int ret = 0;
3772
3773         if ((file->f_mode & FMODE_WRITE) &&
3774             (file->f_flags & O_TRUNC))
3775                 ftrace_pid_reset();
3776
3777         if (file->f_mode & FMODE_READ)
3778                 ret = seq_open(file, &ftrace_pid_sops);
3779
3780         return ret;
3781 }
3782
3783 static ssize_t
3784 ftrace_pid_write(struct file *filp, const char __user *ubuf,
3785                    size_t cnt, loff_t *ppos)
3786 {
3787         char buf[64], *tmp;
3788         long val;
3789         int ret;
3790
3791         if (cnt >= sizeof(buf))
3792                 return -EINVAL;
3793
3794         if (copy_from_user(&buf, ubuf, cnt))
3795                 return -EFAULT;
3796
3797         buf[cnt] = 0;
3798
3799         /*
3800          * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
3801          * to clean the filter quietly.
3802          */
3803         tmp = strstrip(buf);
3804         if (strlen(tmp) == 0)
3805                 return 1;
3806
3807         ret = strict_strtol(tmp, 10, &val);
3808         if (ret < 0)
3809                 return ret;
3810
3811         ret = ftrace_pid_add(val);
3812
3813         return ret ? ret : cnt;
3814 }
3815
3816 static int
3817 ftrace_pid_release(struct inode *inode, struct file *file)
3818 {
3819         if (file->f_mode & FMODE_READ)
3820                 seq_release(inode, file);
3821
3822         return 0;
3823 }
3824
3825 static const struct file_operations ftrace_pid_fops = {
3826         .open           = ftrace_pid_open,
3827         .write          = ftrace_pid_write,
3828         .read           = seq_read,
3829         .llseek         = seq_lseek,
3830         .release        = ftrace_pid_release,
3831 };
3832
3833 static __init int ftrace_init_debugfs(void)
3834 {
3835         struct dentry *d_tracer;
3836
3837         d_tracer = tracing_init_dentry();
3838         if (!d_tracer)
3839                 return 0;
3840
3841         ftrace_init_dyn_debugfs(d_tracer);
3842
3843         trace_create_file("set_ftrace_pid", 0644, d_tracer,
3844                             NULL, &ftrace_pid_fops);
3845
3846         ftrace_profile_debugfs(d_tracer);
3847
3848         return 0;
3849 }
3850 fs_initcall(ftrace_init_debugfs);
3851
3852 /**
3853  * ftrace_kill - kill ftrace
3854  *
3855  * This function should be used by panic code. It stops ftrace
3856  * but in a not so nice way. If you need to simply kill ftrace
3857  * from a non-atomic section, use ftrace_kill.
3858  */
3859 void ftrace_kill(void)
3860 {
3861         ftrace_disabled = 1;
3862         ftrace_enabled = 0;
3863         clear_ftrace_function();
3864 }
3865
3866 /**
3867  * Test if ftrace is dead or not.
3868  */
3869 int ftrace_is_dead(void)
3870 {
3871         return ftrace_disabled;
3872 }
3873
3874 /**
3875  * register_ftrace_function - register a function for profiling
3876  * @ops - ops structure that holds the function for profiling.
3877  *
3878  * Register a function to be called by all functions in the
3879  * kernel.
3880  *
3881  * Note: @ops->func and all the functions it calls must be labeled
3882  *       with "notrace", otherwise it will go into a
3883  *       recursive loop.
3884  */
3885 int register_ftrace_function(struct ftrace_ops *ops)
3886 {
3887         int ret = -1;
3888
3889         mutex_lock(&ftrace_lock);
3890
3891         if (unlikely(ftrace_disabled))
3892                 goto out_unlock;
3893
3894         ret = __register_ftrace_function(ops);
3895         if (!ret)
3896                 ret = ftrace_startup(ops, 0);
3897
3898
3899  out_unlock:
3900         mutex_unlock(&ftrace_lock);
3901         return ret;
3902 }
3903 EXPORT_SYMBOL_GPL(register_ftrace_function);
3904
3905 /**
3906  * unregister_ftrace_function - unregister a function for profiling.
3907  * @ops - ops structure that holds the function to unregister
3908  *
3909  * Unregister a function that was added to be called by ftrace profiling.
3910  */
3911 int unregister_ftrace_function(struct ftrace_ops *ops)
3912 {
3913         int ret;
3914
3915         mutex_lock(&ftrace_lock);
3916         ret = __unregister_ftrace_function(ops);
3917         if (!ret)
3918                 ftrace_shutdown(ops, 0);
3919         mutex_unlock(&ftrace_lock);
3920
3921         return ret;
3922 }
3923 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
3924
3925 int
3926 ftrace_enable_sysctl(struct ctl_table *table, int write,
3927                      void __user *buffer, size_t *lenp,
3928                      loff_t *ppos)
3929 {
3930         int ret = -ENODEV;
3931
3932         mutex_lock(&ftrace_lock);
3933
3934         if (unlikely(ftrace_disabled))
3935                 goto out;
3936
3937         ret = proc_dointvec(table, write, buffer, lenp, ppos);
3938
3939         if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
3940                 goto out;
3941
3942         last_ftrace_enabled = !!ftrace_enabled;
3943
3944         if (ftrace_enabled) {
3945
3946                 ftrace_startup_sysctl();
3947
3948                 /* we are starting ftrace again */
3949                 if (ftrace_ops_list != &ftrace_list_end) {
3950                         if (ftrace_ops_list->next == &ftrace_list_end)
3951                                 ftrace_trace_function = ftrace_ops_list->func;
3952                         else
3953                                 ftrace_trace_function = ftrace_ops_list_func;
3954                 }
3955
3956         } else {
3957                 /* stopping ftrace calls (just send to ftrace_stub) */
3958                 ftrace_trace_function = ftrace_stub;
3959
3960                 ftrace_shutdown_sysctl();
3961         }
3962
3963  out:
3964         mutex_unlock(&ftrace_lock);
3965         return ret;
3966 }
3967
3968 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3969
3970 static int ftrace_graph_active;
3971 static struct notifier_block ftrace_suspend_notifier;
3972
3973 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
3974 {
3975         return 0;
3976 }
3977
3978 /* The callbacks that hook a function */
3979 trace_func_graph_ret_t ftrace_graph_return =
3980                         (trace_func_graph_ret_t)ftrace_stub;
3981 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
3982
3983 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3984 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
3985 {
3986         int i;
3987         int ret = 0;
3988         unsigned long flags;
3989         int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
3990         struct task_struct *g, *t;
3991
3992         for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
3993                 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
3994                                         * sizeof(struct ftrace_ret_stack),
3995                                         GFP_KERNEL);
3996                 if (!ret_stack_list[i]) {
3997                         start = 0;
3998                         end = i;
3999                         ret = -ENOMEM;
4000                         goto free;
4001                 }
4002         }
4003
4004         read_lock_irqsave(&tasklist_lock, flags);
4005         do_each_thread(g, t) {
4006                 if (start == end) {
4007                         ret = -EAGAIN;
4008                         goto unlock;
4009                 }
4010
4011                 if (t->ret_stack == NULL) {
4012                         atomic_set(&t->tracing_graph_pause, 0);
4013                         atomic_set(&t->trace_overrun, 0);
4014                         t->curr_ret_stack = -1;
4015                         /* Make sure the tasks see the -1 first: */
4016                         smp_wmb();
4017                         t->ret_stack = ret_stack_list[start++];
4018                 }
4019         } while_each_thread(g, t);
4020
4021 unlock:
4022         read_unlock_irqrestore(&tasklist_lock, flags);
4023 free:
4024         for (i = start; i < end; i++)
4025                 kfree(ret_stack_list[i]);
4026         return ret;
4027 }
4028
4029 static void
4030 ftrace_graph_probe_sched_switch(void *ignore,
4031                         struct task_struct *prev, struct task_struct *next)
4032 {
4033         unsigned long long timestamp;
4034         int index;
4035
4036         /*
4037          * Does the user want to count the time a function was asleep.
4038          * If so, do not update the time stamps.
4039          */
4040         if (trace_flags & TRACE_ITER_SLEEP_TIME)
4041                 return;
4042
4043         timestamp = trace_clock_local();
4044
4045         prev->ftrace_timestamp = timestamp;
4046
4047         /* only process tasks that we timestamped */
4048         if (!next->ftrace_timestamp)
4049                 return;
4050
4051         /*
4052          * Update all the counters in next to make up for the
4053          * time next was sleeping.
4054          */
4055         timestamp -= next->ftrace_timestamp;
4056
4057         for (index = next->curr_ret_stack; index >= 0; index--)
4058                 next->ret_stack[index].calltime += timestamp;
4059 }
4060
4061 /* Allocate a return stack for each task */
4062 static int start_graph_tracing(void)
4063 {
4064         struct ftrace_ret_stack **ret_stack_list;
4065         int ret, cpu;
4066
4067         ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
4068                                 sizeof(struct ftrace_ret_stack *),
4069                                 GFP_KERNEL);
4070
4071         if (!ret_stack_list)
4072                 return -ENOMEM;
4073
4074         /* The cpu_boot init_task->ret_stack will never be freed */
4075         for_each_online_cpu(cpu) {
4076                 if (!idle_task(cpu)->ret_stack)
4077                         ftrace_graph_init_idle_task(idle_task(cpu), cpu);
4078         }
4079
4080         do {
4081                 ret = alloc_retstack_tasklist(ret_stack_list);
4082         } while (ret == -EAGAIN);
4083
4084         if (!ret) {
4085                 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4086                 if (ret)
4087                         pr_info("ftrace_graph: Couldn't activate tracepoint"
4088                                 " probe to kernel_sched_switch\n");
4089         }
4090
4091         kfree(ret_stack_list);
4092         return ret;
4093 }
4094
4095 /*
4096  * Hibernation protection.
4097  * The state of the current task is too much unstable during
4098  * suspend/restore to disk. We want to protect against that.
4099  */
4100 static int
4101 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
4102                                                         void *unused)
4103 {
4104         switch (state) {
4105         case PM_HIBERNATION_PREPARE:
4106                 pause_graph_tracing();
4107                 break;
4108
4109         case PM_POST_HIBERNATION:
4110                 unpause_graph_tracing();
4111                 break;
4112         }
4113         return NOTIFY_DONE;
4114 }
4115
4116 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
4117                         trace_func_graph_ent_t entryfunc)
4118 {
4119         int ret = 0;
4120
4121         mutex_lock(&ftrace_lock);
4122
4123         /* we currently allow only one tracer registered at a time */
4124         if (ftrace_graph_active) {
4125                 ret = -EBUSY;
4126                 goto out;
4127         }
4128
4129         ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
4130         register_pm_notifier(&ftrace_suspend_notifier);
4131
4132         ftrace_graph_active++;
4133         ret = start_graph_tracing();
4134         if (ret) {
4135                 ftrace_graph_active--;
4136                 goto out;
4137         }
4138
4139         ftrace_graph_return = retfunc;
4140         ftrace_graph_entry = entryfunc;
4141
4142         ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
4143
4144 out:
4145         mutex_unlock(&ftrace_lock);
4146         return ret;
4147 }
4148
4149 void unregister_ftrace_graph(void)
4150 {
4151         mutex_lock(&ftrace_lock);
4152
4153         if (unlikely(!ftrace_graph_active))
4154                 goto out;
4155
4156         ftrace_graph_active--;
4157         ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
4158         ftrace_graph_entry = ftrace_graph_entry_stub;
4159         ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET);
4160         unregister_pm_notifier(&ftrace_suspend_notifier);
4161         unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4162
4163  out:
4164         mutex_unlock(&ftrace_lock);
4165 }
4166
4167 static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
4168
4169 static void
4170 graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
4171 {
4172         atomic_set(&t->tracing_graph_pause, 0);
4173         atomic_set(&t->trace_overrun, 0);
4174         t->ftrace_timestamp = 0;
4175         /* make curr_ret_stack visible before we add the ret_stack */
4176         smp_wmb();
4177         t->ret_stack = ret_stack;
4178 }
4179
4180 /*
4181  * Allocate a return stack for the idle task. May be the first
4182  * time through, or it may be done by CPU hotplug online.
4183  */
4184 void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
4185 {
4186         t->curr_ret_stack = -1;
4187         /*
4188          * The idle task has no parent, it either has its own
4189          * stack or no stack at all.
4190          */
4191         if (t->ret_stack)
4192                 WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
4193
4194         if (ftrace_graph_active) {
4195                 struct ftrace_ret_stack *ret_stack;
4196
4197                 ret_stack = per_cpu(idle_ret_stack, cpu);
4198                 if (!ret_stack) {
4199                         ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4200                                             * sizeof(struct ftrace_ret_stack),
4201                                             GFP_KERNEL);
4202                         if (!ret_stack)
4203                                 return;
4204                         per_cpu(idle_ret_stack, cpu) = ret_stack;
4205                 }
4206                 graph_init_task(t, ret_stack);
4207         }
4208 }
4209
4210 /* Allocate a return stack for newly created task */
4211 void ftrace_graph_init_task(struct task_struct *t)
4212 {
4213         /* Make sure we do not use the parent ret_stack */
4214         t->ret_stack = NULL;
4215         t->curr_ret_stack = -1;
4216
4217         if (ftrace_graph_active) {
4218                 struct ftrace_ret_stack *ret_stack;
4219
4220                 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4221                                 * sizeof(struct ftrace_ret_stack),
4222                                 GFP_KERNEL);
4223                 if (!ret_stack)
4224                         return;
4225                 graph_init_task(t, ret_stack);
4226         }
4227 }
4228
4229 void ftrace_graph_exit_task(struct task_struct *t)
4230 {
4231         struct ftrace_ret_stack *ret_stack = t->ret_stack;
4232
4233         t->ret_stack = NULL;
4234         /* NULL must become visible to IRQs before we free it: */
4235         barrier();
4236
4237         kfree(ret_stack);
4238 }
4239
4240 void ftrace_graph_stop(void)
4241 {
4242         ftrace_stop();
4243 }
4244 #endif