kernel/trace/ftrace.c

   1 /*
   2  * Infrastructure for profiling code inserted by 'gcc -pg'.
   3  *
   4  * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
   5  * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
   6  *
   7  * Originally ported from the -rt patch by:
   8  *   Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
   9  *
  10  * Based on code in the latency_tracer, that is:
  11  *
  12  *  Copyright (C) 2004-2006 Ingo Molnar
  13  *  Copyright (C) 2004 William Lee Irwin III
  14  */
  15
  16 #include <linux/stop_machine.h>
  17 #include <linux/clocksource.h>
  18 #include <linux/kallsyms.h>
  19 #include <linux/seq_file.h>
  20 #include <linux/suspend.h>
  21 #include <linux/debugfs.h>
  22 #include <linux/hardirq.h>
  23 #include <linux/kthread.h>
  24 #include <linux/uaccess.h>
  25 #include <linux/kprobes.h>
  26 #include <linux/ftrace.h>
  27 #include <linux/sysctl.h>
  28 #include <linux/ctype.h>
  29 #include <linux/list.h>
  30 #include <linux/hash.h>
  31
  32 #include <trace/events/sched.h>
  33
  34 #include <asm/ftrace.h>
  35 #include <asm/setup.h>
  36
  37 #include "trace_output.h"
  38 #include "trace_stat.h"
  39
  40 #define FTRACE_WARN_ON(cond)                    \
  41         do {                                    \
  42                 if (WARN_ON(cond))              \
  43                         ftrace_kill();          \
  44         } while (0)
  45
  46 #define FTRACE_WARN_ON_ONCE(cond)               \
  47         do {                                    \
  48                 if (WARN_ON_ONCE(cond))         \
  49                         ftrace_kill();          \
  50         } while (0)
  51
  52 /* hash bits for specific function selection */
  53 #define FTRACE_HASH_BITS 7
  54 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
  55
  56 /* ftrace_enabled is a method to turn ftrace on or off */
  57 int ftrace_enabled __read_mostly;
  58 static int last_ftrace_enabled;
  59
  60 /* Quick disabling of function tracer. */
  61 int function_trace_stop;
  62
  63 /* List for set_ftrace_pid's pids. */
  64 LIST_HEAD(ftrace_pids);
  65 struct ftrace_pid {
  66         struct list_head list;
  67         struct pid *pid;
  68 };
  69
  70 /*
  71  * ftrace_disabled is set when an anomaly is discovered.
  72  * ftrace_disabled is much stronger than ftrace_enabled.
  73  */
  74 static int ftrace_disabled __read_mostly;
  75
  76 static DEFINE_MUTEX(ftrace_lock);
  77
  78 static struct ftrace_ops ftrace_list_end __read_mostly =
  79 {
  80         .func           = ftrace_stub,
  81 };
  82
  83 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
  84 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
  85 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
  86 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
  87
  88 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  89 static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
  90 #endif
  91
  92 static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
  93 {
  94         struct ftrace_ops *op = ftrace_list;
  95
  96         /* in case someone actually ports this to alpha! */
  97         read_barrier_depends();
  98
  99         while (op != &ftrace_list_end) {
 100                 /* silly alpha */
 101                 read_barrier_depends();
 102                 op->func(ip, parent_ip);
 103                 op = op->next;
 104         };
 105 }
 106
 107 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
 108 {
 109         if (!test_tsk_trace_trace(current))
 110                 return;
 111
 112         ftrace_pid_function(ip, parent_ip);
 113 }
 114
 115 static void set_ftrace_pid_function(ftrace_func_t func)
 116 {
 117         /* do not set ftrace_pid_function to itself! */
 118         if (func != ftrace_pid_func)
 119                 ftrace_pid_function = func;
 120 }
 121
 122 /**
 123  * clear_ftrace_function - reset the ftrace function
 124  *
 125  * This NULLs the ftrace function and in essence stops
 126  * tracing.  There may be lag
 127  */
 128 void clear_ftrace_function(void)
 129 {
 130         ftrace_trace_function = ftrace_stub;
 131         __ftrace_trace_function = ftrace_stub;
 132         ftrace_pid_function = ftrace_stub;
 133 }
 134
 135 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 136 /*
 137  * For those archs that do not test ftrace_trace_stop in their
 138  * mcount call site, we need to do it from C.
 139  */
 140 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
 141 {
 142         if (function_trace_stop)
 143                 return;
 144
 145         __ftrace_trace_function(ip, parent_ip);
 146 }
 147 #endif
 148
 149 static int __register_ftrace_function(struct ftrace_ops *ops)
 150 {
 151         ops->next = ftrace_list;
 152         /*
 153          * We are entering ops into the ftrace_list but another
 154          * CPU might be walking that list. We need to make sure
 155          * the ops->next pointer is valid before another CPU sees
 156          * the ops pointer included into the ftrace_list.
 157          */
 158         smp_wmb();
 159         ftrace_list = ops;
 160
 161         if (ftrace_enabled) {
 162                 ftrace_func_t func;
 163
 164                 if (ops->next == &ftrace_list_end)
 165                         func = ops->func;
 166                 else
 167                         func = ftrace_list_func;
 168
 169                 if (!list_empty(&ftrace_pids)) {
 170                         set_ftrace_pid_function(func);
 171                         func = ftrace_pid_func;
 172                 }
 173
 174                 /*
 175                  * For one func, simply call it directly.
 176                  * For more than one func, call the chain.
 177                  */
 178 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 179                 ftrace_trace_function = func;
 180 #else
 181                 __ftrace_trace_function = func;
 182                 ftrace_trace_function = ftrace_test_stop_func;
 183 #endif
 184         }
 185
 186         return 0;
 187 }
 188
 189 static int __unregister_ftrace_function(struct ftrace_ops *ops)
 190 {
 191         struct ftrace_ops **p;
 192
 193         /*
 194          * If we are removing the last function, then simply point
 195          * to the ftrace_stub.
 196          */
 197         if (ftrace_list == ops && ops->next == &ftrace_list_end) {
 198                 ftrace_trace_function = ftrace_stub;
 199                 ftrace_list = &ftrace_list_end;
 200                 return 0;
 201         }
 202
 203         for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
 204                 if (*p == ops)
 205                         break;
 206
 207         if (*p != ops)
 208                 return -1;
 209
 210         *p = (*p)->next;
 211
 212         if (ftrace_enabled) {
 213                 /* If we only have one func left, then call that directly */
 214                 if (ftrace_list->next == &ftrace_list_end) {
 215                         ftrace_func_t func = ftrace_list->func;
 216
 217                         if (!list_empty(&ftrace_pids)) {
 218                                 set_ftrace_pid_function(func);
 219                                 func = ftrace_pid_func;
 220                         }
 221 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 222                         ftrace_trace_function = func;
 223 #else
 224                         __ftrace_trace_function = func;
 225 #endif
 226                 }
 227         }
 228
 229         return 0;
 230 }
 231
 232 static void ftrace_update_pid_func(void)
 233 {
 234         ftrace_func_t func;
 235
 236         if (ftrace_trace_function == ftrace_stub)
 237                 return;
 238
 239 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 240         func = ftrace_trace_function;
 241 #else
 242         func = __ftrace_trace_function;
 243 #endif
 244
 245         if (!list_empty(&ftrace_pids)) {
 246                 set_ftrace_pid_function(func);
 247                 func = ftrace_pid_func;
 248         } else {
 249                 if (func == ftrace_pid_func)
 250                         func = ftrace_pid_function;
 251         }
 252
 253 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 254         ftrace_trace_function = func;
 255 #else
 256         __ftrace_trace_function = func;
 257 #endif
 258 }
 259
 260 #ifdef CONFIG_FUNCTION_PROFILER
 261 struct ftrace_profile {
 262         struct hlist_node               node;
 263         unsigned long                   ip;
 264         unsigned long                   counter;
 265 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 266         unsigned long long              time;
 267 #endif
 268 };
 269
 270 struct ftrace_profile_page {
 271         struct ftrace_profile_page      *next;
 272         unsigned long                   index;
 273         struct ftrace_profile           records[];
 274 };
 275
 276 struct ftrace_profile_stat {
 277         atomic_t                        disabled;
 278         struct hlist_head               *hash;
 279         struct ftrace_profile_page      *pages;
 280         struct ftrace_profile_page      *start;
 281         struct tracer_stat              stat;
 282 };
 283
 284 #define PROFILE_RECORDS_SIZE                                            \
 285         (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
 286
 287 #define PROFILES_PER_PAGE                                       \
 288         (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
 289
 290 static int ftrace_profile_bits __read_mostly;
 291 static int ftrace_profile_enabled __read_mostly;
 292
 293 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
 294 static DEFINE_MUTEX(ftrace_profile_lock);
 295
 296 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
 297
 298 #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
 299
 300 static void *
 301 function_stat_next(void *v, int idx)
 302 {
 303         struct ftrace_profile *rec = v;
 304         struct ftrace_profile_page *pg;
 305
 306         pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
 307
 308  again:
 309         if (idx != 0)
 310                 rec++;
 311
 312         if ((void *)rec >= (void *)&pg->records[pg->index]) {
 313                 pg = pg->next;
 314                 if (!pg)
 315                         return NULL;
 316                 rec = &pg->records[0];
 317                 if (!rec->counter)
 318                         goto again;
 319         }
 320
 321         return rec;
 322 }
 323
 324 static void *function_stat_start(struct tracer_stat *trace)
 325 {
 326         struct ftrace_profile_stat *stat =
 327                 container_of(trace, struct ftrace_profile_stat, stat);
 328
 329         if (!stat || !stat->start)
 330                 return NULL;
 331
 332         return function_stat_next(&stat->start->records[0], 0);
 333 }
 334
 335 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 336 /* function graph compares on total time */
 337 static int function_stat_cmp(void *p1, void *p2)
 338 {
 339         struct ftrace_profile *a = p1;
 340         struct ftrace_profile *b = p2;
 341
 342         if (a->time < b->time)
 343                 return -1;
 344         if (a->time > b->time)
 345                 return 1;
 346         else
 347                 return 0;
 348 }
 349 #else
 350 /* not function graph compares against hits */
 351 static int function_stat_cmp(void *p1, void *p2)
 352 {
 353         struct ftrace_profile *a = p1;
 354         struct ftrace_profile *b = p2;
 355
 356         if (a->counter < b->counter)
 357                 return -1;
 358         if (a->counter > b->counter)
 359                 return 1;
 360         else
 361                 return 0;
 362 }
 363 #endif
 364
 365 static int function_stat_headers(struct seq_file *m)
 366 {
 367 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 368         seq_printf(m, "  Function                               "
 369                    "Hit    Time            Avg\n"
 370                       "  --------                               "
 371                    "---    ----            ---\n");
 372 #else
 373         seq_printf(m, "  Function                               Hit\n"
 374                       "  --------                               ---\n");
 375 #endif
 376         return 0;
 377 }
 378
 379 static int function_stat_show(struct seq_file *m, void *v)
 380 {
 381         struct ftrace_profile *rec = v;
 382         char str[KSYM_SYMBOL_LEN];
 383 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 384         static DEFINE_MUTEX(mutex);
 385         static struct trace_seq s;
 386         unsigned long long avg;
 387 #endif
 388
 389         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 390         seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);
 391
 392 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 393         seq_printf(m, "    ");
 394         avg = rec->time;
 395         do_div(avg, rec->counter);
 396
 397         mutex_lock(&mutex);
 398         trace_seq_init(&s);
 399         trace_print_graph_duration(rec->time, &s);
 400         trace_seq_puts(&s, "    ");
 401         trace_print_graph_duration(avg, &s);
 402         trace_print_seq(m, &s);
 403         mutex_unlock(&mutex);
 404 #endif
 405         seq_putc(m, '\n');
 406
 407         return 0;
 408 }
 409
 410 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
 411 {
 412         struct ftrace_profile_page *pg;
 413
 414         pg = stat->pages = stat->start;
 415
 416         while (pg) {
 417                 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
 418                 pg->index = 0;
 419                 pg = pg->next;
 420         }
 421
 422         memset(stat->hash, 0,
 423                FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
 424 }
 425
 426 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
 427 {
 428         struct ftrace_profile_page *pg;
 429         int functions;
 430         int pages;
 431         int i;
 432
 433         /* If we already allocated, do nothing */
 434         if (stat->pages)
 435                 return 0;
 436
 437         stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
 438         if (!stat->pages)
 439                 return -ENOMEM;
 440
 441 #ifdef CONFIG_DYNAMIC_FTRACE
 442         functions = ftrace_update_tot_cnt;
 443 #else
 444         /*
 445          * We do not know the number of functions that exist because
 446          * dynamic tracing is what counts them. With past experience
 447          * we have around 20K functions. That should be more than enough.
 448          * It is highly unlikely we will execute every function in
 449          * the kernel.
 450          */
 451         functions = 20000;
 452 #endif
 453
 454         pg = stat->start = stat->pages;
 455
 456         pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
 457
 458         for (i = 0; i < pages; i++) {
 459                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
 460                 if (!pg->next)
 461                         goto out_free;
 462                 pg = pg->next;
 463         }
 464
 465         return 0;
 466
 467  out_free:
 468         pg = stat->start;
 469         while (pg) {
 470                 unsigned long tmp = (unsigned long)pg;
 471
 472                 pg = pg->next;
 473                 free_page(tmp);
 474         }
 475
 476         free_page((unsigned long)stat->pages);
 477         stat->pages = NULL;
 478         stat->start = NULL;
 479
 480         return -ENOMEM;
 481 }
 482
 483 static int ftrace_profile_init_cpu(int cpu)
 484 {
 485         struct ftrace_profile_stat *stat;
 486         int size;
 487
 488         stat = &per_cpu(ftrace_profile_stats, cpu);
 489
 490         if (stat->hash) {
 491                 /* If the profile is already created, simply reset it */
 492                 ftrace_profile_reset(stat);
 493                 return 0;
 494         }
 495
 496         /*
 497          * We are profiling all functions, but usually only a few thousand
 498          * functions are hit. We'll make a hash of 1024 items.
 499          */
 500         size = FTRACE_PROFILE_HASH_SIZE;
 501
 502         stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
 503
 504         if (!stat->hash)
 505                 return -ENOMEM;
 506
 507         if (!ftrace_profile_bits) {
 508                 size--;
 509
 510                 for (; size; size >>= 1)
 511                         ftrace_profile_bits++;
 512         }
 513
 514         /* Preallocate the function profiling pages */
 515         if (ftrace_profile_pages_init(stat) < 0) {
 516                 kfree(stat->hash);
 517                 stat->hash = NULL;
 518                 return -ENOMEM;
 519         }
 520
 521         return 0;
 522 }
 523
 524 static int ftrace_profile_init(void)
 525 {
 526         int cpu;
 527         int ret = 0;
 528
 529         for_each_online_cpu(cpu) {
 530                 ret = ftrace_profile_init_cpu(cpu);
 531                 if (ret)
 532                         break;
 533         }
 534
 535         return ret;
 536 }
 537
 538 /* interrupts must be disabled */
 539 static struct ftrace_profile *
 540 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
 541 {
 542         struct ftrace_profile *rec;
 543         struct hlist_head *hhd;
 544         struct hlist_node *n;
 545         unsigned long key;
 546
 547         key = hash_long(ip, ftrace_profile_bits);
 548         hhd = &stat->hash[key];
 549
 550         if (hlist_empty(hhd))
 551                 return NULL;
 552
 553         hlist_for_each_entry_rcu(rec, n, hhd, node) {
 554                 if (rec->ip == ip)
 555                         return rec;
 556         }
 557
 558         return NULL;
 559 }
 560
 561 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
 562                                struct ftrace_profile *rec)
 563 {
 564         unsigned long key;
 565
 566         key = hash_long(rec->ip, ftrace_profile_bits);
 567         hlist_add_head_rcu(&rec->node, &stat->hash[key]);
 568 }
 569
 570 /*
 571  * The memory is already allocated, this simply finds a new record to use.
 572  */
 573 static struct ftrace_profile *
 574 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
 575 {
 576         struct ftrace_profile *rec = NULL;
 577
 578         /* prevent recursion (from NMIs) */
 579         if (atomic_inc_return(&stat->disabled) != 1)
 580                 goto out;
 581
 582         /*
 583          * Try to find the function again since an NMI
 584          * could have added it
 585          */
 586         rec = ftrace_find_profiled_func(stat, ip);
 587         if (rec)
 588                 goto out;
 589
 590         if (stat->pages->index == PROFILES_PER_PAGE) {
 591                 if (!stat->pages->next)
 592                         goto out;
 593                 stat->pages = stat->pages->next;
 594         }
 595
 596         rec = &stat->pages->records[stat->pages->index++];
 597         rec->ip = ip;
 598         ftrace_add_profile(stat, rec);
 599
 600  out:
 601         atomic_dec(&stat->disabled);
 602
 603         return rec;
 604 }
 605
 606 static void
 607 function_profile_call(unsigned long ip, unsigned long parent_ip)
 608 {
 609         struct ftrace_profile_stat *stat;
 610         struct ftrace_profile *rec;
 611         unsigned long flags;
 612
 613         if (!ftrace_profile_enabled)
 614                 return;
 615
 616         local_irq_save(flags);
 617
 618         stat = &__get_cpu_var(ftrace_profile_stats);
 619         if (!stat->hash || !ftrace_profile_enabled)
 620                 goto out;
 621
 622         rec = ftrace_find_profiled_func(stat, ip);
 623         if (!rec) {
 624                 rec = ftrace_profile_alloc(stat, ip);
 625                 if (!rec)
 626                         goto out;
 627         }
 628
 629         rec->counter++;
 630  out:
 631         local_irq_restore(flags);
 632 }
 633
 634 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 635 static int profile_graph_entry(struct ftrace_graph_ent *trace)
 636 {
 637         function_profile_call(trace->func, 0);
 638         return 1;
 639 }
 640
 641 static void profile_graph_return(struct ftrace_graph_ret *trace)
 642 {
 643         struct ftrace_profile_stat *stat;
 644         unsigned long long calltime;
 645         struct ftrace_profile *rec;
 646         unsigned long flags;
 647
 648         local_irq_save(flags);
 649         stat = &__get_cpu_var(ftrace_profile_stats);
 650         if (!stat->hash || !ftrace_profile_enabled)
 651                 goto out;
 652
 653         calltime = trace->rettime - trace->calltime;
 654
 655         if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
 656                 int index;
 657
 658                 index = trace->depth;
 659
 660                 /* Append this call time to the parent time to subtract */
 661                 if (index)
 662                         current->ret_stack[index - 1].subtime += calltime;
 663
 664                 if (current->ret_stack[index].subtime < calltime)
 665                         calltime -= current->ret_stack[index].subtime;
 666                 else
 667                         calltime = 0;
 668         }
 669
 670         rec = ftrace_find_profiled_func(stat, trace->func);
 671         if (rec)
 672                 rec->time += calltime;
 673
 674  out:
 675         local_irq_restore(flags);
 676 }
 677
 678 static int register_ftrace_profiler(void)
 679 {
 680         return register_ftrace_graph(&profile_graph_return,
 681                                      &profile_graph_entry);
 682 }
 683
 684 static void unregister_ftrace_profiler(void)
 685 {
 686         unregister_ftrace_graph();
 687 }
 688 #else
 689 static struct ftrace_ops ftrace_profile_ops __read_mostly =
 690 {
 691         .func           = function_profile_call,
 692 };
 693
 694 static int register_ftrace_profiler(void)
 695 {
 696         return register_ftrace_function(&ftrace_profile_ops);
 697 }
 698
 699 static void unregister_ftrace_profiler(void)
 700 {
 701         unregister_ftrace_function(&ftrace_profile_ops);
 702 }
 703 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 704
 705 static ssize_t
 706 ftrace_profile_write(struct file *filp, const char __user *ubuf,
 707                      size_t cnt, loff_t *ppos)
 708 {
 709         unsigned long val;
 710         char buf[64];           /* big enough to hold a number */
 711         int ret;
 712
 713         if (cnt >= sizeof(buf))
 714                 return -EINVAL;
 715
 716         if (copy_from_user(&buf, ubuf, cnt))
 717                 return -EFAULT;
 718
 719         buf[cnt] = 0;
 720
 721         ret = strict_strtoul(buf, 10, &val);
 722         if (ret < 0)
 723                 return ret;
 724
 725         val = !!val;
 726
 727         mutex_lock(&ftrace_profile_lock);
 728         if (ftrace_profile_enabled ^ val) {
 729                 if (val) {
 730                         ret = ftrace_profile_init();
 731                         if (ret < 0) {
 732                                 cnt = ret;
 733                                 goto out;
 734                         }
 735
 736                         ret = register_ftrace_profiler();
 737                         if (ret < 0) {
 738                                 cnt = ret;
 739                                 goto out;
 740                         }
 741                         ftrace_profile_enabled = 1;
 742                 } else {
 743                         ftrace_profile_enabled = 0;
 744                         /*
 745                          * unregister_ftrace_profiler calls stop_machine
 746                          * so this acts like an synchronize_sched.
 747                          */
 748                         unregister_ftrace_profiler();
 749                 }
 750         }
 751  out:
 752         mutex_unlock(&ftrace_profile_lock);
 753
 754         *ppos += cnt;
 755
 756         return cnt;
 757 }
 758
 759 static ssize_t
 760 ftrace_profile_read(struct file *filp, char __user *ubuf,
 761                      size_t cnt, loff_t *ppos)
 762 {
 763         char buf[64];           /* big enough to hold a number */
 764         int r;
 765
 766         r = sprintf(buf, "%u\n", ftrace_profile_enabled);
 767         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 768 }
 769
 770 static const struct file_operations ftrace_profile_fops = {
 771         .open           = tracing_open_generic,
 772         .read           = ftrace_profile_read,
 773         .write          = ftrace_profile_write,
 774 };
 775
 776 /* used to initialize the real stat files */
 777 static struct tracer_stat function_stats __initdata = {
 778         .name           = "functions",
 779         .stat_start     = function_stat_start,
 780         .stat_next      = function_stat_next,
 781         .stat_cmp       = function_stat_cmp,
 782         .stat_headers   = function_stat_headers,
 783         .stat_show      = function_stat_show
 784 };
 785
 786 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
 787 {
 788         struct ftrace_profile_stat *stat;
 789         struct dentry *entry;
 790         char *name;
 791         int ret;
 792         int cpu;
 793
 794         for_each_possible_cpu(cpu) {
 795                 stat = &per_cpu(ftrace_profile_stats, cpu);
 796
 797                 /* allocate enough for function name + cpu number */
 798                 name = kmalloc(32, GFP_KERNEL);
 799                 if (!name) {
 800                         /*
 801                          * The files created are permanent, if something happens
 802                          * we still do not free memory.
 803                          */
 804                         WARN(1,
 805                              "Could not allocate stat file for cpu %d\n",
 806                              cpu);
 807                         return;
 808                 }
 809                 stat->stat = function_stats;
 810                 snprintf(name, 32, "function%d", cpu);
 811                 stat->stat.name = name;
 812                 ret = register_stat_tracer(&stat->stat);
 813                 if (ret) {
 814                         WARN(1,
 815                              "Could not register function stat for cpu %d\n",
 816                              cpu);
 817                         kfree(name);
 818                         return;
 819                 }
 820         }
 821
 822         entry = debugfs_create_file("function_profile_enabled", 0644,
 823                                     d_tracer, NULL, &ftrace_profile_fops);
 824         if (!entry)
 825                 pr_warning("Could not create debugfs "
 826                            "'function_profile_enabled' entry\n");
 827 }
 828
 829 #else /* CONFIG_FUNCTION_PROFILER */
 830 static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
 831 {
 832 }
 833 #endif /* CONFIG_FUNCTION_PROFILER */
 834
 835 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
 836
 837 #ifdef CONFIG_DYNAMIC_FTRACE
 838
 839 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
 840 # error Dynamic ftrace depends on MCOUNT_RECORD
 841 #endif
 842
 843 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
 844
 845 struct ftrace_func_probe {
 846         struct hlist_node       node;
 847         struct ftrace_probe_ops *ops;
 848         unsigned long           flags;
 849         unsigned long           ip;
 850         void                    *data;
 851         struct rcu_head         rcu;
 852 };
 853
 854 enum {
 855         FTRACE_ENABLE_CALLS             = (1 << 0),
 856         FTRACE_DISABLE_CALLS            = (1 << 1),
 857         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 858         FTRACE_ENABLE_MCOUNT            = (1 << 3),
 859         FTRACE_DISABLE_MCOUNT           = (1 << 4),
 860         FTRACE_START_FUNC_RET           = (1 << 5),
 861         FTRACE_STOP_FUNC_RET            = (1 << 6),
 862 };
 863
 864 static int ftrace_filtered;
 865
 866 static struct dyn_ftrace *ftrace_new_addrs;
 867
 868 static DEFINE_MUTEX(ftrace_regex_lock);
 869
 870 struct ftrace_page {
 871         struct ftrace_page      *next;
 872         int                     index;
 873         struct dyn_ftrace       records[];
 874 };
 875
 876 #define ENTRIES_PER_PAGE \
 877   ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
 878
 879 /* estimate from running different kernels */
 880 #define NR_TO_INIT              10000
 881
 882 static struct ftrace_page       *ftrace_pages_start;
 883 static struct ftrace_page       *ftrace_pages;
 884
 885 static struct dyn_ftrace *ftrace_free_records;
 886
 887 /*
 888  * This is a double for. Do not use 'break' to break out of the loop,
 889  * you must use a goto.
 890  */
 891 #define do_for_each_ftrace_rec(pg, rec)                                 \
 892         for (pg = ftrace_pages_start; pg; pg = pg->next) {              \
 893                 int _____i;                                             \
 894                 for (_____i = 0; _____i < pg->index; _____i++) {        \
 895                         rec = &pg->records[_____i];
 896
 897 #define while_for_each_ftrace_rec()             \
 898                 }                               \
 899         }
 900
 901 #ifdef CONFIG_KPROBES
 902
 903 static int frozen_record_count;
 904
 905 static inline void freeze_record(struct dyn_ftrace *rec)
 906 {
 907         if (!(rec->flags & FTRACE_FL_FROZEN)) {
 908                 rec->flags |= FTRACE_FL_FROZEN;
 909                 frozen_record_count++;
 910         }
 911 }
 912
 913 static inline void unfreeze_record(struct dyn_ftrace *rec)
 914 {
 915         if (rec->flags & FTRACE_FL_FROZEN) {
 916                 rec->flags &= ~FTRACE_FL_FROZEN;
 917                 frozen_record_count--;
 918         }
 919 }
 920
 921 static inline int record_frozen(struct dyn_ftrace *rec)
 922 {
 923         return rec->flags & FTRACE_FL_FROZEN;
 924 }
 925 #else
 926 # define freeze_record(rec)                     ({ 0; })
 927 # define unfreeze_record(rec)                   ({ 0; })
 928 # define record_frozen(rec)                     ({ 0; })
 929 #endif /* CONFIG_KPROBES */
 930
 931 static void ftrace_free_rec(struct dyn_ftrace *rec)
 932 {
 933         rec->freelist = ftrace_free_records;
 934         ftrace_free_records = rec;
 935         rec->flags |= FTRACE_FL_FREE;
 936 }
 937
 938 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
 939 {
 940         struct dyn_ftrace *rec;
 941
 942         /* First check for freed records */
 943         if (ftrace_free_records) {
 944                 rec = ftrace_free_records;
 945
 946                 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
 947                         FTRACE_WARN_ON_ONCE(1);
 948                         ftrace_free_records = NULL;
 949                         return NULL;
 950                 }
 951
 952                 ftrace_free_records = rec->freelist;
 953                 memset(rec, 0, sizeof(*rec));
 954                 return rec;
 955         }
 956
 957         if (ftrace_pages->index == ENTRIES_PER_PAGE) {
 958                 if (!ftrace_pages->next) {
 959                         /* allocate another page */
 960                         ftrace_pages->next =
 961                                 (void *)get_zeroed_page(GFP_KERNEL);
 962                         if (!ftrace_pages->next)
 963                                 return NULL;
 964                 }
 965                 ftrace_pages = ftrace_pages->next;
 966         }
 967
 968         return &ftrace_pages->records[ftrace_pages->index++];
 969 }
 970
 971 static struct dyn_ftrace *
 972 ftrace_record_ip(unsigned long ip)
 973 {
 974         struct dyn_ftrace *rec;
 975
 976         if (ftrace_disabled)
 977                 return NULL;
 978
 979         rec = ftrace_alloc_dyn_node(ip);
 980         if (!rec)
 981                 return NULL;
 982
 983         rec->ip = ip;
 984         rec->newlist = ftrace_new_addrs;
 985         ftrace_new_addrs = rec;
 986
 987         return rec;
 988 }
 989
 990 static void print_ip_ins(const char *fmt, unsigned char *p)
 991 {
 992         int i;
 993
 994         printk(KERN_CONT "%s", fmt);
 995
 996         for (i = 0; i < MCOUNT_INSN_SIZE; i++)
 997                 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
 998 }
 999
1000 static void ftrace_bug(int failed, unsigned long ip)
1001 {
1002         switch (failed) {
1003         case -EFAULT:
1004                 FTRACE_WARN_ON_ONCE(1);
1005                 pr_info("ftrace faulted on modifying ");
1006                 print_ip_sym(ip);
1007                 break;
1008         case -EINVAL:
1009                 FTRACE_WARN_ON_ONCE(1);
1010                 pr_info("ftrace failed to modify ");
1011                 print_ip_sym(ip);
1012                 print_ip_ins(" actual: ", (unsigned char *)ip);
1013                 printk(KERN_CONT "\n");
1014                 break;
1015         case -EPERM:
1016                 FTRACE_WARN_ON_ONCE(1);
1017                 pr_info("ftrace faulted on writing ");
1018                 print_ip_sym(ip);
1019                 break;
1020         default:
1021                 FTRACE_WARN_ON_ONCE(1);
1022                 pr_info("ftrace faulted on unknown error ");
1023                 print_ip_sym(ip);
1024         }
1025 }
1026
1027
1028 static int
1029 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1030 {
1031         unsigned long ftrace_addr;
1032         unsigned long flag = 0UL;
1033
1034         ftrace_addr = (unsigned long)FTRACE_ADDR;
1035
1036         /*
1037          * If this record is not to be traced or we want to disable it,
1038          * then disable it.
1039          *
1040          * If we want to enable it and filtering is off, then enable it.
1041          *
1042          * If we want to enable it and filtering is on, enable it only if
1043          * it's filtered
1044          */
1045         if (enable && !(rec->flags & FTRACE_FL_NOTRACE)) {
1046                 if (!ftrace_filtered || (rec->flags & FTRACE_FL_FILTER))
1047                         flag = FTRACE_FL_ENABLED;
1048         }
1049
1050         /* If the state of this record hasn't changed, then do nothing */
1051         if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1052                 return 0;
1053
1054         if (flag) {
1055                 rec->flags |= FTRACE_FL_ENABLED;
1056                 return ftrace_make_call(rec, ftrace_addr);
1057         }
1058
1059         rec->flags &= ~FTRACE_FL_ENABLED;
1060         return ftrace_make_nop(NULL, rec, ftrace_addr);
1061 }
1062
1063 static void ftrace_replace_code(int enable)
1064 {
1065         struct dyn_ftrace *rec;
1066         struct ftrace_page *pg;
1067         int failed;
1068
1069         do_for_each_ftrace_rec(pg, rec) {
1070                 /*
1071                  * Skip over free records, records that have
1072                  * failed and not converted.
1073                  */
1074                 if (rec->flags & FTRACE_FL_FREE ||
1075                     rec->flags & FTRACE_FL_FAILED ||
1076                     !(rec->flags & FTRACE_FL_CONVERTED))
1077                         continue;
1078
1079                 /* ignore updates to this record's mcount site */
1080                 if (get_kprobe((void *)rec->ip)) {
1081                         freeze_record(rec);
1082                         continue;
1083                 } else {
1084                         unfreeze_record(rec);
1085                 }
1086
1087                 failed = __ftrace_replace_code(rec, enable);
1088                 if (failed) {
1089                         rec->flags |= FTRACE_FL_FAILED;
1090                         ftrace_bug(failed, rec->ip);
1091                         /* Stop processing */
1092                         return;
1093                 }
1094         } while_for_each_ftrace_rec();
1095 }
1096
1097 static int
1098 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1099 {
1100         unsigned long ip;
1101         int ret;
1102
1103         ip = rec->ip;
1104
1105         ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1106         if (ret) {
1107                 ftrace_bug(ret, ip);
1108                 rec->flags |= FTRACE_FL_FAILED;
1109                 return 0;
1110         }
1111         return 1;
1112 }
1113
1114 /*
1115  * archs can override this function if they must do something
1116  * before the modifying code is performed.
1117  */
1118 int __weak ftrace_arch_code_modify_prepare(void)
1119 {
1120         return 0;
1121 }
1122
1123 /*
1124  * archs can override this function if they must do something
1125  * after the modifying code is performed.
1126  */
1127 int __weak ftrace_arch_code_modify_post_process(void)
1128 {
1129         return 0;
1130 }
1131
1132 static int __ftrace_modify_code(void *data)
1133 {
1134         int *command = data;
1135
1136         if (*command & FTRACE_ENABLE_CALLS)
1137                 ftrace_replace_code(1);
1138         else if (*command & FTRACE_DISABLE_CALLS)
1139                 ftrace_replace_code(0);
1140
1141         if (*command & FTRACE_UPDATE_TRACE_FUNC)
1142                 ftrace_update_ftrace_func(ftrace_trace_function);
1143
1144         if (*command & FTRACE_START_FUNC_RET)
1145                 ftrace_enable_ftrace_graph_caller();
1146         else if (*command & FTRACE_STOP_FUNC_RET)
1147                 ftrace_disable_ftrace_graph_caller();
1148
1149         return 0;
1150 }
1151
1152 static void ftrace_run_update_code(int command)
1153 {
1154         int ret;
1155
1156         ret = ftrace_arch_code_modify_prepare();
1157         FTRACE_WARN_ON(ret);
1158         if (ret)
1159                 return;
1160
1161         stop_machine(__ftrace_modify_code, &command, NULL);
1162
1163         ret = ftrace_arch_code_modify_post_process();
1164         FTRACE_WARN_ON(ret);
1165 }
1166
1167 static ftrace_func_t saved_ftrace_func;
1168 static int ftrace_start_up;
1169
1170 static void ftrace_startup_enable(int command)
1171 {
1172         if (saved_ftrace_func != ftrace_trace_function) {
1173                 saved_ftrace_func = ftrace_trace_function;
1174                 command |= FTRACE_UPDATE_TRACE_FUNC;
1175         }
1176
1177         if (!command || !ftrace_enabled)
1178                 return;
1179
1180         ftrace_run_update_code(command);
1181 }
1182
1183 static void ftrace_startup(int command)
1184 {
1185         if (unlikely(ftrace_disabled))
1186                 return;
1187
1188         ftrace_start_up++;
1189         command |= FTRACE_ENABLE_CALLS;
1190
1191         ftrace_startup_enable(command);
1192 }
1193
1194 static void ftrace_shutdown(int command)
1195 {
1196         if (unlikely(ftrace_disabled))
1197                 return;
1198
1199         ftrace_start_up--;
1200         /*
1201          * Just warn in case of unbalance, no need to kill ftrace, it's not
1202          * critical but the ftrace_call callers may be never nopped again after
1203          * further ftrace uses.
1204          */
1205         WARN_ON_ONCE(ftrace_start_up < 0);
1206
1207         if (!ftrace_start_up)
1208                 command |= FTRACE_DISABLE_CALLS;
1209
1210         if (saved_ftrace_func != ftrace_trace_function) {
1211                 saved_ftrace_func = ftrace_trace_function;
1212                 command |= FTRACE_UPDATE_TRACE_FUNC;
1213         }
1214
1215         if (!command || !ftrace_enabled)
1216                 return;
1217
1218         ftrace_run_update_code(command);
1219 }
1220
1221 static void ftrace_startup_sysctl(void)
1222 {
1223         int command = FTRACE_ENABLE_MCOUNT;
1224
1225         if (unlikely(ftrace_disabled))
1226                 return;
1227
1228         /* Force update next time */
1229         saved_ftrace_func = NULL;
1230         /* ftrace_start_up is true if we want ftrace running */
1231         if (ftrace_start_up)
1232                 command |= FTRACE_ENABLE_CALLS;
1233
1234         ftrace_run_update_code(command);
1235 }
1236
1237 static void ftrace_shutdown_sysctl(void)
1238 {
1239         int command = FTRACE_DISABLE_MCOUNT;
1240
1241         if (unlikely(ftrace_disabled))
1242                 return;
1243
1244         /* ftrace_start_up is true if ftrace is running */
1245         if (ftrace_start_up)
1246                 command |= FTRACE_DISABLE_CALLS;
1247
1248         ftrace_run_update_code(command);
1249 }
1250
1251 static cycle_t          ftrace_update_time;
1252 static unsigned long    ftrace_update_cnt;
1253 unsigned long           ftrace_update_tot_cnt;
1254
1255 static int ftrace_update_code(struct module *mod)
1256 {
1257         struct dyn_ftrace *p;
1258         cycle_t start, stop;
1259
1260         start = ftrace_now(raw_smp_processor_id());
1261         ftrace_update_cnt = 0;
1262
1263         while (ftrace_new_addrs) {
1264
1265                 /* If something went wrong, bail without enabling anything */
1266                 if (unlikely(ftrace_disabled))
1267                         return -1;
1268
1269                 p = ftrace_new_addrs;
1270                 ftrace_new_addrs = p->newlist;
1271                 p->flags = 0L;
1272
1273                 /*
1274                  * Do the initial record convertion from mcount jump
1275                  * to the NOP instructions.
1276                  */
1277                 if (!ftrace_code_disable(mod, p)) {
1278                         ftrace_free_rec(p);
1279                         continue;
1280                 }
1281
1282                 p->flags |= FTRACE_FL_CONVERTED;
1283                 ftrace_update_cnt++;
1284
1285                 /*
1286                  * If the tracing is enabled, go ahead and enable the record.
1287                  *
1288                  * The reason not to enable the record immediatelly is the
1289                  * inherent check of ftrace_make_nop/ftrace_make_call for
1290                  * correct previous instructions.  Making first the NOP
1291                  * conversion puts the module to the correct state, thus
1292                  * passing the ftrace_make_call check.
1293                  */
1294                 if (ftrace_start_up) {
1295                         int failed = __ftrace_replace_code(p, 1);
1296                         if (failed) {
1297                                 ftrace_bug(failed, p->ip);
1298                                 ftrace_free_rec(p);
1299                         }
1300                 }
1301         }
1302
1303         stop = ftrace_now(raw_smp_processor_id());
1304         ftrace_update_time = stop - start;
1305         ftrace_update_tot_cnt += ftrace_update_cnt;
1306
1307         return 0;
1308 }
1309
1310 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
1311 {
1312         struct ftrace_page *pg;
1313         int cnt;
1314         int i;
1315
1316         /* allocate a few pages */
1317         ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
1318         if (!ftrace_pages_start)
1319                 return -1;
1320
1321         /*
1322          * Allocate a few more pages.
1323          *
1324          * TODO: have some parser search vmlinux before
1325          *   final linking to find all calls to ftrace.
1326          *   Then we can:
1327          *    a) know how many pages to allocate.
1328          *     and/or
1329          *    b) set up the table then.
1330          *
1331          *  The dynamic code is still necessary for
1332          *  modules.
1333          */
1334
1335         pg = ftrace_pages = ftrace_pages_start;
1336
1337         cnt = num_to_init / ENTRIES_PER_PAGE;
1338         pr_info("ftrace: allocating %ld entries in %d pages\n",
1339                 num_to_init, cnt + 1);
1340
1341         for (i = 0; i < cnt; i++) {
1342                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
1343
1344                 /* If we fail, we'll try later anyway */
1345                 if (!pg->next)
1346                         break;
1347
1348                 pg = pg->next;
1349         }
1350
1351         return 0;
1352 }
1353
1354 enum {
1355         FTRACE_ITER_FILTER      = (1 << 0),
1356         FTRACE_ITER_NOTRACE     = (1 << 1),
1357         FTRACE_ITER_FAILURES    = (1 << 2),
1358         FTRACE_ITER_PRINTALL    = (1 << 3),
1359         FTRACE_ITER_HASH        = (1 << 4),
1360 };
1361
1362 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1363
1364 struct ftrace_iterator {
1365         struct ftrace_page      *pg;
1366         int                     hidx;
1367         int                     idx;
1368         unsigned                flags;
1369         struct trace_parser     parser;
1370 };
1371
1372 static void *
1373 t_hash_next(struct seq_file *m, void *v, loff_t *pos)
1374 {
1375         struct ftrace_iterator *iter = m->private;
1376         struct hlist_node *hnd = v;
1377         struct hlist_head *hhd;
1378
1379         WARN_ON(!(iter->flags & FTRACE_ITER_HASH));
1380
1381         (*pos)++;
1382
1383  retry:
1384         if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
1385                 return NULL;
1386
1387         hhd = &ftrace_func_hash[iter->hidx];
1388
1389         if (hlist_empty(hhd)) {
1390                 iter->hidx++;
1391                 hnd = NULL;
1392                 goto retry;
1393         }
1394
1395         if (!hnd)
1396                 hnd = hhd->first;
1397         else {
1398                 hnd = hnd->next;
1399                 if (!hnd) {
1400                         iter->hidx++;
1401                         goto retry;
1402                 }
1403         }
1404
1405         return hnd;
1406 }
1407
1408 static void *t_hash_start(struct seq_file *m, loff_t *pos)
1409 {
1410         struct ftrace_iterator *iter = m->private;
1411         void *p = NULL;
1412         loff_t l;
1413
1414         if (!(iter->flags & FTRACE_ITER_HASH))
1415                 *pos = 0;
1416
1417         iter->flags |= FTRACE_ITER_HASH;
1418
1419         iter->hidx = 0;
1420         for (l = 0; l <= *pos; ) {
1421                 p = t_hash_next(m, p, &l);
1422                 if (!p)
1423                         break;
1424         }
1425         return p;
1426 }
1427
1428 static int t_hash_show(struct seq_file *m, void *v)
1429 {
1430         struct ftrace_func_probe *rec;
1431         struct hlist_node *hnd = v;
1432
1433         rec = hlist_entry(hnd, struct ftrace_func_probe, node);
1434
1435         if (rec->ops->print)
1436                 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
1437
1438         seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
1439
1440         if (rec->data)
1441                 seq_printf(m, ":%p", rec->data);
1442         seq_putc(m, '\n');
1443
1444         return 0;
1445 }
1446
1447 static void *
1448 t_next(struct seq_file *m, void *v, loff_t *pos)
1449 {
1450         struct ftrace_iterator *iter = m->private;
1451         struct dyn_ftrace *rec = NULL;
1452
1453         if (iter->flags & FTRACE_ITER_HASH)
1454                 return t_hash_next(m, v, pos);
1455
1456         (*pos)++;
1457
1458         if (iter->flags & FTRACE_ITER_PRINTALL)
1459                 return NULL;
1460
1461  retry:
1462         if (iter->idx >= iter->pg->index) {
1463                 if (iter->pg->next) {
1464                         iter->pg = iter->pg->next;
1465                         iter->idx = 0;
1466                         goto retry;
1467                 }
1468         } else {
1469                 rec = &iter->pg->records[iter->idx++];
1470                 if ((rec->flags & FTRACE_FL_FREE) ||
1471
1472                     (!(iter->flags & FTRACE_ITER_FAILURES) &&
1473                      (rec->flags & FTRACE_FL_FAILED)) ||
1474
1475                     ((iter->flags & FTRACE_ITER_FAILURES) &&
1476                      !(rec->flags & FTRACE_FL_FAILED)) ||
1477
1478                     ((iter->flags & FTRACE_ITER_FILTER) &&
1479                      !(rec->flags & FTRACE_FL_FILTER)) ||
1480
1481                     ((iter->flags & FTRACE_ITER_NOTRACE) &&
1482                      !(rec->flags & FTRACE_FL_NOTRACE))) {
1483                         rec = NULL;
1484                         goto retry;
1485                 }
1486         }
1487
1488         return rec;
1489 }
1490
1491 static void *t_start(struct seq_file *m, loff_t *pos)
1492 {
1493         struct ftrace_iterator *iter = m->private;
1494         void *p = NULL;
1495         loff_t l;
1496
1497         mutex_lock(&ftrace_lock);
1498         /*
1499          * For set_ftrace_filter reading, if we have the filter
1500          * off, we can short cut and just print out that all
1501          * functions are enabled.
1502          */
1503         if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) {
1504                 if (*pos > 0)
1505                         return t_hash_start(m, pos);
1506                 iter->flags |= FTRACE_ITER_PRINTALL;
1507                 return iter;
1508         }
1509
1510         if (iter->flags & FTRACE_ITER_HASH)
1511                 return t_hash_start(m, pos);
1512
1513         iter->pg = ftrace_pages_start;
1514         iter->idx = 0;
1515         for (l = 0; l <= *pos; ) {
1516                 p = t_next(m, p, &l);
1517                 if (!p)
1518                         break;
1519         }
1520
1521         if (!p && iter->flags & FTRACE_ITER_FILTER)
1522                 return t_hash_start(m, pos);
1523
1524         return p;
1525 }
1526
1527 static void t_stop(struct seq_file *m, void *p)
1528 {
1529         mutex_unlock(&ftrace_lock);
1530 }
1531
1532 static int t_show(struct seq_file *m, void *v)
1533 {
1534         struct ftrace_iterator *iter = m->private;
1535         struct dyn_ftrace *rec = v;
1536
1537         if (iter->flags & FTRACE_ITER_HASH)
1538                 return t_hash_show(m, v);
1539
1540         if (iter->flags & FTRACE_ITER_PRINTALL) {
1541                 seq_printf(m, "#### all functions enabled ####\n");
1542                 return 0;
1543         }
1544
1545         if (!rec)
1546                 return 0;
1547
1548         seq_printf(m, "%ps\n", (void *)rec->ip);
1549
1550         return 0;
1551 }
1552
1553 static const struct seq_operations show_ftrace_seq_ops = {
1554         .start = t_start,
1555         .next = t_next,
1556         .stop = t_stop,
1557         .show = t_show,
1558 };
1559
1560 static int
1561 ftrace_avail_open(struct inode *inode, struct file *file)
1562 {
1563         struct ftrace_iterator *iter;
1564         int ret;
1565
1566         if (unlikely(ftrace_disabled))
1567                 return -ENODEV;
1568
1569         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1570         if (!iter)
1571                 return -ENOMEM;
1572
1573         iter->pg = ftrace_pages_start;
1574
1575         ret = seq_open(file, &show_ftrace_seq_ops);
1576         if (!ret) {
1577                 struct seq_file *m = file->private_data;
1578
1579                 m->private = iter;
1580         } else {
1581                 kfree(iter);
1582         }
1583
1584         return ret;
1585 }
1586
1587 static int
1588 ftrace_failures_open(struct inode *inode, struct file *file)
1589 {
1590         int ret;
1591         struct seq_file *m;
1592         struct ftrace_iterator *iter;
1593
1594         ret = ftrace_avail_open(inode, file);
1595         if (!ret) {
1596                 m = (struct seq_file *)file->private_data;
1597                 iter = (struct ftrace_iterator *)m->private;
1598                 iter->flags = FTRACE_ITER_FAILURES;
1599         }
1600
1601         return ret;
1602 }
1603
1604
1605 static void ftrace_filter_reset(int enable)
1606 {
1607         struct ftrace_page *pg;
1608         struct dyn_ftrace *rec;
1609         unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1610
1611         mutex_lock(&ftrace_lock);
1612         if (enable)
1613                 ftrace_filtered = 0;
1614         do_for_each_ftrace_rec(pg, rec) {
1615                 if (rec->flags & FTRACE_FL_FAILED)
1616                         continue;
1617                 rec->flags &= ~type;
1618         } while_for_each_ftrace_rec();
1619         mutex_unlock(&ftrace_lock);
1620 }
1621
1622 static int
1623 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
1624 {
1625         struct ftrace_iterator *iter;
1626         int ret = 0;
1627
1628         if (unlikely(ftrace_disabled))
1629                 return -ENODEV;
1630
1631         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1632         if (!iter)
1633                 return -ENOMEM;
1634
1635         if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
1636                 kfree(iter);
1637                 return -ENOMEM;
1638         }
1639
1640         mutex_lock(&ftrace_regex_lock);
1641         if ((file->f_mode & FMODE_WRITE) &&
1642             (file->f_flags & O_TRUNC))
1643                 ftrace_filter_reset(enable);
1644
1645         if (file->f_mode & FMODE_READ) {
1646                 iter->pg = ftrace_pages_start;
1647                 iter->flags = enable ? FTRACE_ITER_FILTER :
1648                         FTRACE_ITER_NOTRACE;
1649
1650                 ret = seq_open(file, &show_ftrace_seq_ops);
1651                 if (!ret) {
1652                         struct seq_file *m = file->private_data;
1653                         m->private = iter;
1654                 } else {
1655                         trace_parser_put(&iter->parser);
1656                         kfree(iter);
1657                 }
1658         } else
1659                 file->private_data = iter;
1660         mutex_unlock(&ftrace_regex_lock);
1661
1662         return ret;
1663 }
1664
1665 static int
1666 ftrace_filter_open(struct inode *inode, struct file *file)
1667 {
1668         return ftrace_regex_open(inode, file, 1);
1669 }
1670
1671 static int
1672 ftrace_notrace_open(struct inode *inode, struct file *file)
1673 {
1674         return ftrace_regex_open(inode, file, 0);
1675 }
1676
1677 static loff_t
1678 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1679 {
1680         loff_t ret;
1681
1682         if (file->f_mode & FMODE_READ)
1683                 ret = seq_lseek(file, offset, origin);
1684         else
1685                 file->f_pos = ret = 1;
1686
1687         return ret;
1688 }
1689
1690 static int ftrace_match(char *str, char *regex, int len, int type)
1691 {
1692         int matched = 0;
1693         int slen;
1694
1695         switch (type) {
1696         case MATCH_FULL:
1697                 if (strcmp(str, regex) == 0)
1698                         matched = 1;
1699                 break;
1700         case MATCH_FRONT_ONLY:
1701                 if (strncmp(str, regex, len) == 0)
1702                         matched = 1;
1703                 break;
1704         case MATCH_MIDDLE_ONLY:
1705                 if (strstr(str, regex))
1706                         matched = 1;
1707                 break;
1708         case MATCH_END_ONLY:
1709                 slen = strlen(str);
1710                 if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
1711                         matched = 1;
1712                 break;
1713         }
1714
1715         return matched;
1716 }
1717
1718 static int
1719 ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
1720 {
1721         char str[KSYM_SYMBOL_LEN];
1722
1723         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1724         return ftrace_match(str, regex, len, type);
1725 }
1726
1727 static int ftrace_match_records(char *buff, int len, int enable)
1728 {
1729         unsigned int search_len;
1730         struct ftrace_page *pg;
1731         struct dyn_ftrace *rec;
1732         unsigned long flag;
1733         char *search;
1734         int type;
1735         int not;
1736         int found = 0;
1737
1738         flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1739         type = filter_parse_regex(buff, len, &search, &not);
1740
1741         search_len = strlen(search);
1742
1743         mutex_lock(&ftrace_lock);
1744         do_for_each_ftrace_rec(pg, rec) {
1745
1746                 if (rec->flags & FTRACE_FL_FAILED)
1747                         continue;
1748
1749                 if (ftrace_match_record(rec, search, search_len, type)) {
1750                         if (not)
1751                                 rec->flags &= ~flag;
1752                         else
1753                                 rec->flags |= flag;
1754                         found = 1;
1755                 }
1756                 /*
1757                  * Only enable filtering if we have a function that
1758                  * is filtered on.
1759                  */
1760                 if (enable && (rec->flags & FTRACE_FL_FILTER))
1761                         ftrace_filtered = 1;
1762         } while_for_each_ftrace_rec();
1763         mutex_unlock(&ftrace_lock);
1764
1765         return found;
1766 }
1767
1768 static int
1769 ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
1770                            char *regex, int len, int type)
1771 {
1772         char str[KSYM_SYMBOL_LEN];
1773         char *modname;
1774
1775         kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
1776
1777         if (!modname || strcmp(modname, mod))
1778                 return 0;
1779
1780         /* blank search means to match all funcs in the mod */
1781         if (len)
1782                 return ftrace_match(str, regex, len, type);
1783         else
1784                 return 1;
1785 }
1786
1787 static int ftrace_match_module_records(char *buff, char *mod, int enable)
1788 {
1789         unsigned search_len = 0;
1790         struct ftrace_page *pg;
1791         struct dyn_ftrace *rec;
1792         int type = MATCH_FULL;
1793         char *search = buff;
1794         unsigned long flag;
1795         int not = 0;
1796         int found = 0;
1797
1798         flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1799
1800         /* blank or '*' mean the same */
1801         if (strcmp(buff, "*") == 0)
1802                 buff[0] = 0;
1803
1804         /* handle the case of 'dont filter this module' */
1805         if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
1806                 buff[0] = 0;
1807                 not = 1;
1808         }
1809
1810         if (strlen(buff)) {
1811                 type = filter_parse_regex(buff, strlen(buff), &search, &not);
1812                 search_len = strlen(search);
1813         }
1814
1815         mutex_lock(&ftrace_lock);
1816         do_for_each_ftrace_rec(pg, rec) {
1817
1818                 if (rec->flags & FTRACE_FL_FAILED)
1819                         continue;
1820
1821                 if (ftrace_match_module_record(rec, mod,
1822                                                search, search_len, type)) {
1823                         if (not)
1824                                 rec->flags &= ~flag;
1825                         else
1826                                 rec->flags |= flag;
1827                         found = 1;
1828                 }
1829                 if (enable && (rec->flags & FTRACE_FL_FILTER))
1830                         ftrace_filtered = 1;
1831
1832         } while_for_each_ftrace_rec();
1833         mutex_unlock(&ftrace_lock);
1834
1835         return found;
1836 }
1837
1838 /*
1839  * We register the module command as a template to show others how
1840  * to register the a command as well.
1841  */
1842
1843 static int
1844 ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
1845 {
1846         char *mod;
1847
1848         /*
1849          * cmd == 'mod' because we only registered this func
1850          * for the 'mod' ftrace_func_command.
1851          * But if you register one func with multiple commands,
1852          * you can tell which command was used by the cmd
1853          * parameter.
1854          */
1855
1856         /* we must have a module name */
1857         if (!param)
1858                 return -EINVAL;
1859
1860         mod = strsep(&param, ":");
1861         if (!strlen(mod))
1862                 return -EINVAL;
1863
1864         if (ftrace_match_module_records(func, mod, enable))
1865                 return 0;
1866         return -EINVAL;
1867 }
1868
1869 static struct ftrace_func_command ftrace_mod_cmd = {
1870         .name                   = "mod",
1871         .func                   = ftrace_mod_callback,
1872 };
1873
1874 static int __init ftrace_mod_cmd_init(void)
1875 {
1876         return register_ftrace_command(&ftrace_mod_cmd);
1877 }
1878 device_initcall(ftrace_mod_cmd_init);
1879
1880 static void
1881 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
1882 {
1883         struct ftrace_func_probe *entry;
1884         struct hlist_head *hhd;
1885         struct hlist_node *n;
1886         unsigned long key;
1887         int resched;
1888
1889         key = hash_long(ip, FTRACE_HASH_BITS);
1890
1891         hhd = &ftrace_func_hash[key];
1892
1893         if (hlist_empty(hhd))
1894                 return;
1895
1896         /*
1897          * Disable preemption for these calls to prevent a RCU grace
1898          * period. This syncs the hash iteration and freeing of items
1899          * on the hash. rcu_read_lock is too dangerous here.
1900          */
1901         resched = ftrace_preempt_disable();
1902         hlist_for_each_entry_rcu(entry, n, hhd, node) {
1903                 if (entry->ip == ip)
1904                         entry->ops->func(ip, parent_ip, &entry->data);
1905         }
1906         ftrace_preempt_enable(resched);
1907 }
1908
1909 static struct ftrace_ops trace_probe_ops __read_mostly =
1910 {
1911         .func           = function_trace_probe_call,
1912 };
1913
1914 static int ftrace_probe_registered;
1915
1916 static void __enable_ftrace_function_probe(void)
1917 {
1918         int i;
1919
1920         if (ftrace_probe_registered)
1921                 return;
1922
1923         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1924                 struct hlist_head *hhd = &ftrace_func_hash[i];
1925                 if (hhd->first)
1926                         break;
1927         }
1928         /* Nothing registered? */
1929         if (i == FTRACE_FUNC_HASHSIZE)
1930                 return;
1931
1932         __register_ftrace_function(&trace_probe_ops);
1933         ftrace_startup(0);
1934         ftrace_probe_registered = 1;
1935 }
1936
1937 static void __disable_ftrace_function_probe(void)
1938 {
1939         int i;
1940
1941         if (!ftrace_probe_registered)
1942                 return;
1943
1944         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1945                 struct hlist_head *hhd = &ftrace_func_hash[i];
1946                 if (hhd->first)
1947                         return;
1948         }
1949
1950         /* no more funcs left */
1951         __unregister_ftrace_function(&trace_probe_ops);
1952         ftrace_shutdown(0);
1953         ftrace_probe_registered = 0;
1954 }
1955
1956
1957 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
1958 {
1959         struct ftrace_func_probe *entry =
1960                 container_of(rhp, struct ftrace_func_probe, rcu);
1961
1962         if (entry->ops->free)
1963                 entry->ops->free(&entry->data);
1964         kfree(entry);
1965 }
1966
1967
1968 int
1969 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
1970                               void *data)
1971 {
1972         struct ftrace_func_probe *entry;
1973         struct ftrace_page *pg;
1974         struct dyn_ftrace *rec;
1975         int type, len, not;
1976         unsigned long key;
1977         int count = 0;
1978         char *search;
1979
1980         type = filter_parse_regex(glob, strlen(glob), &search, &not);
1981         len = strlen(search);
1982
1983         /* we do not support '!' for function probes */
1984         if (WARN_ON(not))
1985                 return -EINVAL;
1986
1987         mutex_lock(&ftrace_lock);
1988         do_for_each_ftrace_rec(pg, rec) {
1989
1990                 if (rec->flags & FTRACE_FL_FAILED)
1991                         continue;
1992
1993                 if (!ftrace_match_record(rec, search, len, type))
1994                         continue;
1995
1996                 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1997                 if (!entry) {
1998                         /* If we did not process any, then return error */
1999                         if (!count)
2000                                 count = -ENOMEM;
2001                         goto out_unlock;
2002                 }
2003
2004                 count++;
2005
2006                 entry->data = data;
2007
2008                 /*
2009                  * The caller might want to do something special
2010                  * for each function we find. We call the callback
2011                  * to give the caller an opportunity to do so.
2012                  */
2013                 if (ops->callback) {
2014                         if (ops->callback(rec->ip, &entry->data) < 0) {
2015                                 /* caller does not like this func */
2016                                 kfree(entry);
2017                                 continue;
2018                         }
2019                 }
2020
2021                 entry->ops = ops;
2022                 entry->ip = rec->ip;
2023
2024                 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2025                 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2026
2027         } while_for_each_ftrace_rec();
2028         __enable_ftrace_function_probe();
2029
2030  out_unlock:
2031         mutex_unlock(&ftrace_lock);
2032
2033         return count;
2034 }
2035
2036 enum {
2037         PROBE_TEST_FUNC         = 1,
2038         PROBE_TEST_DATA         = 2
2039 };
2040
2041 static void
2042 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2043                                   void *data, int flags)
2044 {
2045         struct ftrace_func_probe *entry;
2046         struct hlist_node *n, *tmp;
2047         char str[KSYM_SYMBOL_LEN];
2048         int type = MATCH_FULL;
2049         int i, len = 0;
2050         char *search;
2051
2052         if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
2053                 glob = NULL;
2054         else if (glob) {
2055                 int not;
2056
2057                 type = filter_parse_regex(glob, strlen(glob), &search, &not);
2058                 len = strlen(search);
2059
2060                 /* we do not support '!' for function probes */
2061                 if (WARN_ON(not))
2062                         return;
2063         }
2064
2065         mutex_lock(&ftrace_lock);
2066         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2067                 struct hlist_head *hhd = &ftrace_func_hash[i];
2068
2069                 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
2070
2071                         /* break up if statements for readability */
2072                         if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2073                                 continue;
2074
2075                         if ((flags & PROBE_TEST_DATA) && entry->data != data)
2076                                 continue;
2077
2078                         /* do this last, since it is the most expensive */
2079                         if (glob) {
2080                                 kallsyms_lookup(entry->ip, NULL, NULL,
2081                                                 NULL, str);
2082                                 if (!ftrace_match(str, glob, len, type))
2083                                         continue;
2084                         }
2085
2086                         hlist_del(&entry->node);
2087                         call_rcu(&entry->rcu, ftrace_free_entry_rcu);
2088                 }
2089         }
2090         __disable_ftrace_function_probe();
2091         mutex_unlock(&ftrace_lock);
2092 }
2093
2094 void
2095 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2096                                 void *data)
2097 {
2098         __unregister_ftrace_function_probe(glob, ops, data,
2099                                           PROBE_TEST_FUNC | PROBE_TEST_DATA);
2100 }
2101
2102 void
2103 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
2104 {
2105         __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
2106 }
2107
2108 void unregister_ftrace_function_probe_all(char *glob)
2109 {
2110         __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
2111 }
2112
2113 static LIST_HEAD(ftrace_commands);
2114 static DEFINE_MUTEX(ftrace_cmd_mutex);
2115
2116 int register_ftrace_command(struct ftrace_func_command *cmd)
2117 {
2118         struct ftrace_func_command *p;
2119         int ret = 0;
2120
2121         mutex_lock(&ftrace_cmd_mutex);
2122         list_for_each_entry(p, &ftrace_commands, list) {
2123                 if (strcmp(cmd->name, p->name) == 0) {
2124                         ret = -EBUSY;
2125                         goto out_unlock;
2126                 }
2127         }
2128         list_add(&cmd->list, &ftrace_commands);
2129  out_unlock:
2130         mutex_unlock(&ftrace_cmd_mutex);
2131
2132         return ret;
2133 }
2134
2135 int unregister_ftrace_command(struct ftrace_func_command *cmd)
2136 {
2137         struct ftrace_func_command *p, *n;
2138         int ret = -ENODEV;
2139
2140         mutex_lock(&ftrace_cmd_mutex);
2141         list_for_each_entry_safe(p, n, &ftrace_commands, list) {
2142                 if (strcmp(cmd->name, p->name) == 0) {
2143                         ret = 0;
2144                         list_del_init(&p->list);
2145                         goto out_unlock;
2146                 }
2147         }
2148  out_unlock:
2149         mutex_unlock(&ftrace_cmd_mutex);
2150
2151         return ret;
2152 }
2153
2154 static int ftrace_process_regex(char *buff, int len, int enable)
2155 {
2156         char *func, *command, *next = buff;
2157         struct ftrace_func_command *p;
2158         int ret = -EINVAL;
2159
2160         func = strsep(&next, ":");
2161
2162         if (!next) {
2163                 if (ftrace_match_records(func, len, enable))
2164                         return 0;
2165                 return ret;
2166         }
2167
2168         /* command found */
2169
2170         command = strsep(&next, ":");
2171
2172         mutex_lock(&ftrace_cmd_mutex);
2173         list_for_each_entry(p, &ftrace_commands, list) {
2174                 if (strcmp(p->name, command) == 0) {
2175                         ret = p->func(func, command, next, enable);
2176                         goto out_unlock;
2177                 }
2178         }
2179  out_unlock:
2180         mutex_unlock(&ftrace_cmd_mutex);
2181
2182         return ret;
2183 }
2184
2185 static ssize_t
2186 ftrace_regex_write(struct file *file, const char __user *ubuf,
2187                    size_t cnt, loff_t *ppos, int enable)
2188 {
2189         struct ftrace_iterator *iter;
2190         struct trace_parser *parser;
2191         ssize_t ret, read;
2192
2193         if (!cnt)
2194                 return 0;
2195
2196         mutex_lock(&ftrace_regex_lock);
2197
2198         if (file->f_mode & FMODE_READ) {
2199                 struct seq_file *m = file->private_data;
2200                 iter = m->private;
2201         } else
2202                 iter = file->private_data;
2203
2204         parser = &iter->parser;
2205         read = trace_get_user(parser, ubuf, cnt, ppos);
2206
2207         if (read >= 0 && trace_parser_loaded(parser) &&
2208             !trace_parser_cont(parser)) {
2209                 ret = ftrace_process_regex(parser->buffer,
2210                                            parser->idx, enable);
2211                 trace_parser_clear(parser);
2212                 if (ret)
2213                         goto out_unlock;
2214         }
2215
2216         ret = read;
2217 out_unlock:
2218         mutex_unlock(&ftrace_regex_lock);
2219
2220         return ret;
2221 }
2222
2223 static ssize_t
2224 ftrace_filter_write(struct file *file, const char __user *ubuf,
2225                     size_t cnt, loff_t *ppos)
2226 {
2227         return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
2228 }
2229
2230 static ssize_t
2231 ftrace_notrace_write(struct file *file, const char __user *ubuf,
2232                      size_t cnt, loff_t *ppos)
2233 {
2234         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
2235 }
2236
2237 static void
2238 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
2239 {
2240         if (unlikely(ftrace_disabled))
2241                 return;
2242
2243         mutex_lock(&ftrace_regex_lock);
2244         if (reset)
2245                 ftrace_filter_reset(enable);
2246         if (buf)
2247                 ftrace_match_records(buf, len, enable);
2248         mutex_unlock(&ftrace_regex_lock);
2249 }
2250
2251 /**
2252  * ftrace_set_filter - set a function to filter on in ftrace
2253  * @buf - the string that holds the function filter text.
2254  * @len - the length of the string.
2255  * @reset - non zero to reset all filters before applying this filter.
2256  *
2257  * Filters denote which functions should be enabled when tracing is enabled.
2258  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2259  */
2260 void ftrace_set_filter(unsigned char *buf, int len, int reset)
2261 {
2262         ftrace_set_regex(buf, len, reset, 1);
2263 }
2264
2265 /**
2266  * ftrace_set_notrace - set a function to not trace in ftrace
2267  * @buf - the string that holds the function notrace text.
2268  * @len - the length of the string.
2269  * @reset - non zero to reset all filters before applying this filter.
2270  *
2271  * Notrace Filters denote which functions should not be enabled when tracing
2272  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2273  * for tracing.
2274  */
2275 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
2276 {
2277         ftrace_set_regex(buf, len, reset, 0);
2278 }
2279
2280 /*
2281  * command line interface to allow users to set filters on boot up.
2282  */
2283 #define FTRACE_FILTER_SIZE              COMMAND_LINE_SIZE
2284 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
2285 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
2286
2287 static int __init set_ftrace_notrace(char *str)
2288 {
2289         strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
2290         return 1;
2291 }
2292 __setup("ftrace_notrace=", set_ftrace_notrace);
2293
2294 static int __init set_ftrace_filter(char *str)
2295 {
2296         strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
2297         return 1;
2298 }
2299 __setup("ftrace_filter=", set_ftrace_filter);
2300
2301 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2302 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
2303 static int __init set_graph_function(char *str)
2304 {
2305         strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
2306         return 1;
2307 }
2308 __setup("ftrace_graph_filter=", set_graph_function);
2309
2310 static void __init set_ftrace_early_graph(char *buf)
2311 {
2312         int ret;
2313         char *func;
2314
2315         while (buf) {
2316                 func = strsep(&buf, ",");
2317                 /* we allow only one expression at a time */
2318                 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
2319                                       func);
2320                 if (ret)
2321                         printk(KERN_DEBUG "ftrace: function %s not "
2322                                           "traceable\n", func);
2323         }
2324 }
2325 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2326
2327 static void __init set_ftrace_early_filter(char *buf, int enable)
2328 {
2329         char *func;
2330
2331         while (buf) {
2332                 func = strsep(&buf, ",");
2333                 ftrace_set_regex(func, strlen(func), 0, enable);
2334         }
2335 }
2336
2337 static void __init set_ftrace_early_filters(void)
2338 {
2339         if (ftrace_filter_buf[0])
2340                 set_ftrace_early_filter(ftrace_filter_buf, 1);
2341         if (ftrace_notrace_buf[0])
2342                 set_ftrace_early_filter(ftrace_notrace_buf, 0);
2343 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2344         if (ftrace_graph_buf[0])
2345                 set_ftrace_early_graph(ftrace_graph_buf);
2346 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2347 }
2348
2349 static int
2350 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
2351 {
2352         struct seq_file *m = (struct seq_file *)file->private_data;
2353         struct ftrace_iterator *iter;
2354         struct trace_parser *parser;
2355
2356         mutex_lock(&ftrace_regex_lock);
2357         if (file->f_mode & FMODE_READ) {
2358                 iter = m->private;
2359
2360                 seq_release(inode, file);
2361         } else
2362                 iter = file->private_data;
2363
2364         parser = &iter->parser;
2365         if (trace_parser_loaded(parser)) {
2366                 parser->buffer[parser->idx] = 0;
2367                 ftrace_match_records(parser->buffer, parser->idx, enable);
2368         }
2369
2370         mutex_lock(&ftrace_lock);
2371         if (ftrace_start_up && ftrace_enabled)
2372                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
2373         mutex_unlock(&ftrace_lock);
2374
2375         trace_parser_put(parser);
2376         kfree(iter);
2377
2378         mutex_unlock(&ftrace_regex_lock);
2379         return 0;
2380 }
2381
2382 static int
2383 ftrace_filter_release(struct inode *inode, struct file *file)
2384 {
2385         return ftrace_regex_release(inode, file, 1);
2386 }
2387
2388 static int
2389 ftrace_notrace_release(struct inode *inode, struct file *file)
2390 {
2391         return ftrace_regex_release(inode, file, 0);
2392 }
2393
2394 static const struct file_operations ftrace_avail_fops = {
2395         .open = ftrace_avail_open,
2396         .read = seq_read,
2397         .llseek = seq_lseek,
2398         .release = seq_release_private,
2399 };
2400
2401 static const struct file_operations ftrace_failures_fops = {
2402         .open = ftrace_failures_open,
2403         .read = seq_read,
2404         .llseek = seq_lseek,
2405         .release = seq_release_private,
2406 };
2407
2408 static const struct file_operations ftrace_filter_fops = {
2409         .open = ftrace_filter_open,
2410         .read = seq_read,
2411         .write = ftrace_filter_write,
2412         .llseek = ftrace_regex_lseek,
2413         .release = ftrace_filter_release,
2414 };
2415
2416 static const struct file_operations ftrace_notrace_fops = {
2417         .open = ftrace_notrace_open,
2418         .read = seq_read,
2419         .write = ftrace_notrace_write,
2420         .llseek = ftrace_regex_lseek,
2421         .release = ftrace_notrace_release,
2422 };
2423
2424 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2425
2426 static DEFINE_MUTEX(graph_lock);
2427
2428 int ftrace_graph_count;
2429 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
2430
2431 static void *
2432 __g_next(struct seq_file *m, loff_t *pos)
2433 {
2434         if (*pos >= ftrace_graph_count)
2435                 return NULL;
2436         return &ftrace_graph_funcs[*pos];
2437 }
2438
2439 static void *
2440 g_next(struct seq_file *m, void *v, loff_t *pos)
2441 {
2442         (*pos)++;
2443         return __g_next(m, pos);
2444 }
2445
2446 static void *g_start(struct seq_file *m, loff_t *pos)
2447 {
2448         mutex_lock(&graph_lock);
2449
2450         /* Nothing, tell g_show to print all functions are enabled */
2451         if (!ftrace_graph_count && !*pos)
2452                 return (void *)1;
2453
2454         return __g_next(m, pos);
2455 }
2456
2457 static void g_stop(struct seq_file *m, void *p)
2458 {
2459         mutex_unlock(&graph_lock);
2460 }
2461
2462 static int g_show(struct seq_file *m, void *v)
2463 {
2464         unsigned long *ptr = v;
2465
2466         if (!ptr)
2467                 return 0;
2468
2469         if (ptr == (unsigned long *)1) {
2470                 seq_printf(m, "#### all functions enabled ####\n");
2471                 return 0;
2472         }
2473
2474         seq_printf(m, "%ps\n", (void *)*ptr);
2475
2476         return 0;
2477 }
2478
2479 static const struct seq_operations ftrace_graph_seq_ops = {
2480         .start = g_start,
2481         .next = g_next,
2482         .stop = g_stop,
2483         .show = g_show,
2484 };
2485
2486 static int
2487 ftrace_graph_open(struct inode *inode, struct file *file)
2488 {
2489         int ret = 0;
2490
2491         if (unlikely(ftrace_disabled))
2492                 return -ENODEV;
2493
2494         mutex_lock(&graph_lock);
2495         if ((file->f_mode & FMODE_WRITE) &&
2496             (file->f_flags & O_TRUNC)) {
2497                 ftrace_graph_count = 0;
2498                 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
2499         }
2500         mutex_unlock(&graph_lock);
2501
2502         if (file->f_mode & FMODE_READ)
2503                 ret = seq_open(file, &ftrace_graph_seq_ops);
2504
2505         return ret;
2506 }
2507
2508 static int
2509 ftrace_graph_release(struct inode *inode, struct file *file)
2510 {
2511         if (file->f_mode & FMODE_READ)
2512                 seq_release(inode, file);
2513         return 0;
2514 }
2515
2516 static int
2517 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
2518 {
2519         struct dyn_ftrace *rec;
2520         struct ftrace_page *pg;
2521         int search_len;
2522         int found = 0;
2523         int type, not;
2524         char *search;
2525         bool exists;
2526         int i;
2527
2528         if (ftrace_disabled)
2529                 return -ENODEV;
2530
2531         /* decode regex */
2532         type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
2533         if (not)
2534                 return -EINVAL;
2535
2536         search_len = strlen(search);
2537
2538         mutex_lock(&ftrace_lock);
2539         do_for_each_ftrace_rec(pg, rec) {
2540
2541                 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
2542                         break;
2543
2544                 if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
2545                         continue;
2546
2547                 if (ftrace_match_record(rec, search, search_len, type)) {
2548                         /* ensure it is not already in the array */
2549                         exists = false;
2550                         for (i = 0; i < *idx; i++)
2551                                 if (array[i] == rec->ip) {
2552                                         exists = true;
2553                                         break;
2554                                 }
2555                         if (!exists)
2556                                 array[(*idx)++] = rec->ip;
2557                         found = 1;
2558                 }
2559         } while_for_each_ftrace_rec();
2560
2561         mutex_unlock(&ftrace_lock);
2562
2563         return found ? 0 : -EINVAL;
2564 }
2565
2566 static ssize_t
2567 ftrace_graph_write(struct file *file, const char __user *ubuf,
2568                    size_t cnt, loff_t *ppos)
2569 {
2570         struct trace_parser parser;
2571         ssize_t read, ret;
2572
2573         if (!cnt || cnt < 0)
2574                 return 0;
2575
2576         mutex_lock(&graph_lock);
2577
2578         if (ftrace_graph_count >= FTRACE_GRAPH_MAX_FUNCS) {
2579                 ret = -EBUSY;
2580                 goto out_unlock;
2581         }
2582
2583         if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
2584                 ret = -ENOMEM;
2585                 goto out_unlock;
2586         }
2587
2588         read = trace_get_user(&parser, ubuf, cnt, ppos);
2589
2590         if (read >= 0 && trace_parser_loaded((&parser))) {
2591                 parser.buffer[parser.idx] = 0;
2592
2593                 /* we allow only one expression at a time */
2594                 ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
2595                                         parser.buffer);
2596                 if (ret)
2597                         goto out_free;
2598         }
2599
2600         ret = read;
2601
2602 out_free:
2603         trace_parser_put(&parser);
2604 out_unlock:
2605         mutex_unlock(&graph_lock);
2606
2607         return ret;
2608 }
2609
2610 static const struct file_operations ftrace_graph_fops = {
2611         .open           = ftrace_graph_open,
2612         .read           = seq_read,
2613         .write          = ftrace_graph_write,
2614         .release        = ftrace_graph_release,
2615 };
2616 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2617
2618 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
2619 {
2620
2621         trace_create_file("available_filter_functions", 0444,
2622                         d_tracer, NULL, &ftrace_avail_fops);
2623
2624         trace_create_file("failures", 0444,
2625                         d_tracer, NULL, &ftrace_failures_fops);
2626
2627         trace_create_file("set_ftrace_filter", 0644, d_tracer,
2628                         NULL, &ftrace_filter_fops);
2629
2630         trace_create_file("set_ftrace_notrace", 0644, d_tracer,
2631                                     NULL, &ftrace_notrace_fops);
2632
2633 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2634         trace_create_file("set_graph_function", 0444, d_tracer,
2635                                     NULL,
2636                                     &ftrace_graph_fops);
2637 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2638
2639         return 0;
2640 }
2641
2642 static int ftrace_process_locs(struct module *mod,
2643                                unsigned long *start,
2644                                unsigned long *end)
2645 {
2646         unsigned long *p;
2647         unsigned long addr;
2648         unsigned long flags;
2649
2650         mutex_lock(&ftrace_lock);
2651         p = start;
2652         while (p < end) {
2653                 addr = ftrace_call_adjust(*p++);
2654                 /*
2655                  * Some architecture linkers will pad between
2656                  * the different mcount_loc sections of different
2657                  * object files to satisfy alignments.
2658                  * Skip any NULL pointers.
2659                  */
2660                 if (!addr)
2661                         continue;
2662                 ftrace_record_ip(addr);
2663         }
2664
2665         /* disable interrupts to prevent kstop machine */
2666         local_irq_save(flags);
2667         ftrace_update_code(mod);
2668         local_irq_restore(flags);
2669         mutex_unlock(&ftrace_lock);
2670
2671         return 0;
2672 }
2673
2674 #ifdef CONFIG_MODULES
2675 void ftrace_release_mod(struct module *mod)
2676 {
2677         struct dyn_ftrace *rec;
2678         struct ftrace_page *pg;
2679
2680         if (ftrace_disabled)
2681                 return;
2682
2683         mutex_lock(&ftrace_lock);
2684         do_for_each_ftrace_rec(pg, rec) {
2685                 if (within_module_core(rec->ip, mod)) {
2686                         /*
2687                          * rec->ip is changed in ftrace_free_rec()
2688                          * It should not between s and e if record was freed.
2689                          */
2690                         FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
2691                         ftrace_free_rec(rec);
2692                 }
2693         } while_for_each_ftrace_rec();
2694         mutex_unlock(&ftrace_lock);
2695 }
2696
2697 static void ftrace_init_module(struct module *mod,
2698                                unsigned long *start, unsigned long *end)
2699 {
2700         if (ftrace_disabled || start == end)
2701                 return;
2702         ftrace_process_locs(mod, start, end);
2703 }
2704
2705 static int ftrace_module_notify(struct notifier_block *self,
2706                                 unsigned long val, void *data)
2707 {
2708         struct module *mod = data;
2709
2710         switch (val) {
2711         case MODULE_STATE_COMING:
2712                 ftrace_init_module(mod, mod->ftrace_callsites,
2713                                    mod->ftrace_callsites +
2714                                    mod->num_ftrace_callsites);
2715                 break;
2716         case MODULE_STATE_GOING:
2717                 ftrace_release_mod(mod);
2718                 break;
2719         }
2720
2721         return 0;
2722 }
2723 #else
2724 static int ftrace_module_notify(struct notifier_block *self,
2725                                 unsigned long val, void *data)
2726 {
2727         return 0;
2728 }
2729 #endif /* CONFIG_MODULES */
2730
2731 struct notifier_block ftrace_module_nb = {
2732         .notifier_call = ftrace_module_notify,
2733         .priority = 0,
2734 };
2735
2736 extern unsigned long __start_mcount_loc[];
2737 extern unsigned long __stop_mcount_loc[];
2738
2739 void __init ftrace_init(void)
2740 {
2741         unsigned long count, addr, flags;
2742         int ret;
2743
2744         /* Keep the ftrace pointer to the stub */
2745         addr = (unsigned long)ftrace_stub;
2746
2747         local_irq_save(flags);
2748         ftrace_dyn_arch_init(&addr);
2749         local_irq_restore(flags);
2750
2751         /* ftrace_dyn_arch_init places the return code in addr */
2752         if (addr)
2753                 goto failed;
2754
2755         count = __stop_mcount_loc - __start_mcount_loc;
2756
2757         ret = ftrace_dyn_table_alloc(count);
2758         if (ret)
2759                 goto failed;
2760
2761         last_ftrace_enabled = ftrace_enabled = 1;
2762
2763         ret = ftrace_process_locs(NULL,
2764                                   __start_mcount_loc,
2765                                   __stop_mcount_loc);
2766
2767         ret = register_module_notifier(&ftrace_module_nb);
2768         if (ret)
2769                 pr_warning("Failed to register trace ftrace module notifier\n");
2770
2771         set_ftrace_early_filters();
2772
2773         return;
2774  failed:
2775         ftrace_disabled = 1;
2776 }
2777
2778 #else
2779
2780 static int __init ftrace_nodyn_init(void)
2781 {
2782         ftrace_enabled = 1;
2783         return 0;
2784 }
2785 device_initcall(ftrace_nodyn_init);
2786
2787 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
2788 static inline void ftrace_startup_enable(int command) { }
2789 /* Keep as macros so we do not need to define the commands */
2790 # define ftrace_startup(command)        do { } while (0)
2791 # define ftrace_shutdown(command)       do { } while (0)
2792 # define ftrace_startup_sysctl()        do { } while (0)
2793 # define ftrace_shutdown_sysctl()       do { } while (0)
2794 #endif /* CONFIG_DYNAMIC_FTRACE */
2795
2796 static void clear_ftrace_swapper(void)
2797 {
2798         struct task_struct *p;
2799         int cpu;
2800
2801         get_online_cpus();
2802         for_each_online_cpu(cpu) {
2803                 p = idle_task(cpu);
2804                 clear_tsk_trace_trace(p);
2805         }
2806         put_online_cpus();
2807 }
2808
2809 static void set_ftrace_swapper(void)
2810 {
2811         struct task_struct *p;
2812         int cpu;
2813
2814         get_online_cpus();
2815         for_each_online_cpu(cpu) {
2816                 p = idle_task(cpu);
2817                 set_tsk_trace_trace(p);
2818         }
2819         put_online_cpus();
2820 }
2821
2822 static void clear_ftrace_pid(struct pid *pid)
2823 {
2824         struct task_struct *p;
2825
2826         rcu_read_lock();
2827         do_each_pid_task(pid, PIDTYPE_PID, p) {
2828                 clear_tsk_trace_trace(p);
2829         } while_each_pid_task(pid, PIDTYPE_PID, p);
2830         rcu_read_unlock();
2831
2832         put_pid(pid);
2833 }
2834
2835 static void set_ftrace_pid(struct pid *pid)
2836 {
2837         struct task_struct *p;
2838
2839         rcu_read_lock();
2840         do_each_pid_task(pid, PIDTYPE_PID, p) {
2841                 set_tsk_trace_trace(p);
2842         } while_each_pid_task(pid, PIDTYPE_PID, p);
2843         rcu_read_unlock();
2844 }
2845
2846 static void clear_ftrace_pid_task(struct pid *pid)
2847 {
2848         if (pid == ftrace_swapper_pid)
2849                 clear_ftrace_swapper();
2850         else
2851                 clear_ftrace_pid(pid);
2852 }
2853
2854 static void set_ftrace_pid_task(struct pid *pid)
2855 {
2856         if (pid == ftrace_swapper_pid)
2857                 set_ftrace_swapper();
2858         else
2859                 set_ftrace_pid(pid);
2860 }
2861
2862 static int ftrace_pid_add(int p)
2863 {
2864         struct pid *pid;
2865         struct ftrace_pid *fpid;
2866         int ret = -EINVAL;
2867
2868         mutex_lock(&ftrace_lock);
2869
2870         if (!p)
2871                 pid = ftrace_swapper_pid;
2872         else
2873                 pid = find_get_pid(p);
2874
2875         if (!pid)
2876                 goto out;
2877
2878         ret = 0;
2879
2880         list_for_each_entry(fpid, &ftrace_pids, list)
2881                 if (fpid->pid == pid)
2882                         goto out_put;
2883
2884         ret = -ENOMEM;
2885
2886         fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
2887         if (!fpid)
2888                 goto out_put;
2889
2890         list_add(&fpid->list, &ftrace_pids);
2891         fpid->pid = pid;
2892
2893         set_ftrace_pid_task(pid);
2894
2895         ftrace_update_pid_func();
2896         ftrace_startup_enable(0);
2897
2898         mutex_unlock(&ftrace_lock);
2899         return 0;
2900
2901 out_put:
2902         if (pid != ftrace_swapper_pid)
2903                 put_pid(pid);
2904
2905 out:
2906         mutex_unlock(&ftrace_lock);
2907         return ret;
2908 }
2909
2910 static void ftrace_pid_reset(void)
2911 {
2912         struct ftrace_pid *fpid, *safe;
2913
2914         mutex_lock(&ftrace_lock);
2915         list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
2916                 struct pid *pid = fpid->pid;
2917
2918                 clear_ftrace_pid_task(pid);
2919
2920                 list_del(&fpid->list);
2921                 kfree(fpid);
2922         }
2923
2924         ftrace_update_pid_func();
2925         ftrace_startup_enable(0);
2926
2927         mutex_unlock(&ftrace_lock);
2928 }
2929
2930 static void *fpid_start(struct seq_file *m, loff_t *pos)
2931 {
2932         mutex_lock(&ftrace_lock);
2933
2934         if (list_empty(&ftrace_pids) && (!*pos))
2935                 return (void *) 1;
2936
2937         return seq_list_start(&ftrace_pids, *pos);
2938 }
2939
2940 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
2941 {
2942         if (v == (void *)1)
2943                 return NULL;
2944
2945         return seq_list_next(v, &ftrace_pids, pos);
2946 }
2947
2948 static void fpid_stop(struct seq_file *m, void *p)
2949 {
2950         mutex_unlock(&ftrace_lock);
2951 }
2952
2953 static int fpid_show(struct seq_file *m, void *v)
2954 {
2955         const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
2956
2957         if (v == (void *)1) {
2958                 seq_printf(m, "no pid\n");
2959                 return 0;
2960         }
2961
2962         if (fpid->pid == ftrace_swapper_pid)
2963                 seq_printf(m, "swapper tasks\n");
2964         else
2965                 seq_printf(m, "%u\n", pid_vnr(fpid->pid));
2966
2967         return 0;
2968 }
2969
2970 static const struct seq_operations ftrace_pid_sops = {
2971         .start = fpid_start,
2972         .next = fpid_next,
2973         .stop = fpid_stop,
2974         .show = fpid_show,
2975 };
2976
2977 static int
2978 ftrace_pid_open(struct inode *inode, struct file *file)
2979 {
2980         int ret = 0;
2981
2982         if ((file->f_mode & FMODE_WRITE) &&
2983             (file->f_flags & O_TRUNC))
2984                 ftrace_pid_reset();
2985
2986         if (file->f_mode & FMODE_READ)
2987                 ret = seq_open(file, &ftrace_pid_sops);
2988
2989         return ret;
2990 }
2991
2992 static ssize_t
2993 ftrace_pid_write(struct file *filp, const char __user *ubuf,
2994                    size_t cnt, loff_t *ppos)
2995 {
2996         char buf[64], *tmp;
2997         long val;
2998         int ret;
2999
3000         if (cnt >= sizeof(buf))
3001                 return -EINVAL;
3002
3003         if (copy_from_user(&buf, ubuf, cnt))
3004                 return -EFAULT;
3005
3006         buf[cnt] = 0;
3007
3008         /*
3009          * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
3010          * to clean the filter quietly.
3011          */
3012         tmp = strstrip(buf);
3013         if (strlen(tmp) == 0)
3014                 return 1;
3015
3016         ret = strict_strtol(tmp, 10, &val);
3017         if (ret < 0)
3018                 return ret;
3019
3020         ret = ftrace_pid_add(val);
3021
3022         return ret ? ret : cnt;
3023 }
3024
3025 static int
3026 ftrace_pid_release(struct inode *inode, struct file *file)
3027 {
3028         if (file->f_mode & FMODE_READ)
3029                 seq_release(inode, file);
3030
3031         return 0;
3032 }
3033
3034 static const struct file_operations ftrace_pid_fops = {
3035         .open           = ftrace_pid_open,
3036         .write          = ftrace_pid_write,
3037         .read           = seq_read,
3038         .llseek         = seq_lseek,
3039         .release        = ftrace_pid_release,
3040 };
3041
3042 static __init int ftrace_init_debugfs(void)
3043 {
3044         struct dentry *d_tracer;
3045
3046         d_tracer = tracing_init_dentry();
3047         if (!d_tracer)
3048                 return 0;
3049
3050         ftrace_init_dyn_debugfs(d_tracer);
3051
3052         trace_create_file("set_ftrace_pid", 0644, d_tracer,
3053                             NULL, &ftrace_pid_fops);
3054
3055         ftrace_profile_debugfs(d_tracer);
3056
3057         return 0;
3058 }
3059 fs_initcall(ftrace_init_debugfs);
3060
3061 /**
3062  * ftrace_kill - kill ftrace
3063  *
3064  * This function should be used by panic code. It stops ftrace
3065  * but in a not so nice way. If you need to simply kill ftrace
3066  * from a non-atomic section, use ftrace_kill.
3067  */
3068 void ftrace_kill(void)
3069 {
3070         ftrace_disabled = 1;
3071         ftrace_enabled = 0;
3072         clear_ftrace_function();
3073 }
3074
3075 /**
3076  * register_ftrace_function - register a function for profiling
3077  * @ops - ops structure that holds the function for profiling.
3078  *
3079  * Register a function to be called by all functions in the
3080  * kernel.
3081  *
3082  * Note: @ops->func and all the functions it calls must be labeled
3083  *       with "notrace", otherwise it will go into a
3084  *       recursive loop.
3085  */
3086 int register_ftrace_function(struct ftrace_ops *ops)
3087 {
3088         int ret;
3089
3090         if (unlikely(ftrace_disabled))
3091                 return -1;
3092
3093         mutex_lock(&ftrace_lock);
3094
3095         ret = __register_ftrace_function(ops);
3096         ftrace_startup(0);
3097
3098         mutex_unlock(&ftrace_lock);
3099         return ret;
3100 }
3101
3102 /**
3103  * unregister_ftrace_function - unregister a function for profiling.
3104  * @ops - ops structure that holds the function to unregister
3105  *
3106  * Unregister a function that was added to be called by ftrace profiling.
3107  */
3108 int unregister_ftrace_function(struct ftrace_ops *ops)
3109 {
3110         int ret;
3111
3112         mutex_lock(&ftrace_lock);
3113         ret = __unregister_ftrace_function(ops);
3114         ftrace_shutdown(0);
3115         mutex_unlock(&ftrace_lock);
3116
3117         return ret;
3118 }
3119
3120 int
3121 ftrace_enable_sysctl(struct ctl_table *table, int write,
3122                      void __user *buffer, size_t *lenp,
3123                      loff_t *ppos)
3124 {
3125         int ret;
3126
3127         if (unlikely(ftrace_disabled))
3128                 return -ENODEV;
3129
3130         mutex_lock(&ftrace_lock);
3131
3132         ret  = proc_dointvec(table, write, buffer, lenp, ppos);
3133
3134         if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
3135                 goto out;
3136
3137         last_ftrace_enabled = !!ftrace_enabled;
3138
3139         if (ftrace_enabled) {
3140
3141                 ftrace_startup_sysctl();
3142
3143                 /* we are starting ftrace again */
3144                 if (ftrace_list != &ftrace_list_end) {
3145                         if (ftrace_list->next == &ftrace_list_end)
3146                                 ftrace_trace_function = ftrace_list->func;
3147                         else
3148                                 ftrace_trace_function = ftrace_list_func;
3149                 }
3150
3151         } else {
3152                 /* stopping ftrace calls (just send to ftrace_stub) */
3153                 ftrace_trace_function = ftrace_stub;
3154
3155                 ftrace_shutdown_sysctl();
3156         }
3157
3158  out:
3159         mutex_unlock(&ftrace_lock);
3160         return ret;
3161 }
3162
3163 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3164
3165 static int ftrace_graph_active;
3166 static struct notifier_block ftrace_suspend_notifier;
3167
3168 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
3169 {
3170         return 0;
3171 }
3172
3173 /* The callbacks that hook a function */
3174 trace_func_graph_ret_t ftrace_graph_return =
3175                         (trace_func_graph_ret_t)ftrace_stub;
3176 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
3177
3178 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3179 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
3180 {
3181         int i;
3182         int ret = 0;
3183         unsigned long flags;
3184         int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
3185         struct task_struct *g, *t;
3186
3187         for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
3188                 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
3189                                         * sizeof(struct ftrace_ret_stack),
3190                                         GFP_KERNEL);
3191                 if (!ret_stack_list[i]) {
3192                         start = 0;
3193                         end = i;
3194                         ret = -ENOMEM;
3195                         goto free;
3196                 }
3197         }
3198
3199         read_lock_irqsave(&tasklist_lock, flags);
3200         do_each_thread(g, t) {
3201                 if (start == end) {
3202                         ret = -EAGAIN;
3203                         goto unlock;
3204                 }
3205
3206                 if (t->ret_stack == NULL) {
3207                         atomic_set(&t->tracing_graph_pause, 0);
3208                         atomic_set(&t->trace_overrun, 0);
3209                         t->curr_ret_stack = -1;
3210                         /* Make sure the tasks see the -1 first: */
3211                         smp_wmb();
3212                         t->ret_stack = ret_stack_list[start++];
3213                 }
3214         } while_each_thread(g, t);
3215
3216 unlock:
3217         read_unlock_irqrestore(&tasklist_lock, flags);
3218 free:
3219         for (i = start; i < end; i++)
3220                 kfree(ret_stack_list[i]);
3221         return ret;
3222 }
3223
3224 static void
3225 ftrace_graph_probe_sched_switch(struct rq *__rq, struct task_struct *prev,
3226                                 struct task_struct *next)
3227 {
3228         unsigned long long timestamp;
3229         int index;
3230
3231         /*
3232          * Does the user want to count the time a function was asleep.
3233          * If so, do not update the time stamps.
3234          */
3235         if (trace_flags & TRACE_ITER_SLEEP_TIME)
3236                 return;
3237
3238         timestamp = trace_clock_local();
3239
3240         prev->ftrace_timestamp = timestamp;
3241
3242         /* only process tasks that we timestamped */
3243         if (!next->ftrace_timestamp)
3244                 return;
3245
3246         /*
3247          * Update all the counters in next to make up for the
3248          * time next was sleeping.
3249          */
3250         timestamp -= next->ftrace_timestamp;
3251
3252         for (index = next->curr_ret_stack; index >= 0; index--)
3253                 next->ret_stack[index].calltime += timestamp;
3254 }
3255
3256 /* Allocate a return stack for each task */
3257 static int start_graph_tracing(void)
3258 {
3259         struct ftrace_ret_stack **ret_stack_list;
3260         int ret, cpu;
3261
3262         ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
3263                                 sizeof(struct ftrace_ret_stack *),
3264                                 GFP_KERNEL);
3265
3266         if (!ret_stack_list)
3267                 return -ENOMEM;
3268
3269         /* The cpu_boot init_task->ret_stack will never be freed */
3270         for_each_online_cpu(cpu) {
3271                 if (!idle_task(cpu)->ret_stack)
3272                         ftrace_graph_init_task(idle_task(cpu));
3273         }
3274
3275         do {
3276                 ret = alloc_retstack_tasklist(ret_stack_list);
3277         } while (ret == -EAGAIN);
3278
3279         if (!ret) {
3280                 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch);
3281                 if (ret)
3282                         pr_info("ftrace_graph: Couldn't activate tracepoint"
3283                                 " probe to kernel_sched_switch\n");
3284         }
3285
3286         kfree(ret_stack_list);
3287         return ret;
3288 }
3289
3290 /*
3291  * Hibernation protection.
3292  * The state of the current task is too much unstable during
3293  * suspend/restore to disk. We want to protect against that.
3294  */
3295 static int
3296 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
3297                                                         void *unused)
3298 {
3299         switch (state) {
3300         case PM_HIBERNATION_PREPARE:
3301                 pause_graph_tracing();
3302                 break;
3303
3304         case PM_POST_HIBERNATION:
3305                 unpause_graph_tracing();
3306                 break;
3307         }
3308         return NOTIFY_DONE;
3309 }
3310
3311 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
3312                         trace_func_graph_ent_t entryfunc)
3313 {
3314         int ret = 0;
3315
3316         mutex_lock(&ftrace_lock);
3317
3318         /* we currently allow only one tracer registered at a time */
3319         if (ftrace_graph_active) {
3320                 ret = -EBUSY;
3321                 goto out;
3322         }
3323
3324         ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
3325         register_pm_notifier(&ftrace_suspend_notifier);
3326
3327         ftrace_graph_active++;
3328         ret = start_graph_tracing();
3329         if (ret) {
3330                 ftrace_graph_active--;
3331                 goto out;
3332         }
3333
3334         ftrace_graph_return = retfunc;
3335         ftrace_graph_entry = entryfunc;
3336
3337         ftrace_startup(FTRACE_START_FUNC_RET);
3338
3339 out:
3340         mutex_unlock(&ftrace_lock);
3341         return ret;
3342 }
3343
3344 void unregister_ftrace_graph(void)
3345 {
3346         mutex_lock(&ftrace_lock);
3347
3348         if (unlikely(!ftrace_graph_active))
3349                 goto out;
3350
3351         ftrace_graph_active--;
3352         unregister_trace_sched_switch(ftrace_graph_probe_sched_switch);
3353         ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
3354         ftrace_graph_entry = ftrace_graph_entry_stub;
3355         ftrace_shutdown(FTRACE_STOP_FUNC_RET);
3356         unregister_pm_notifier(&ftrace_suspend_notifier);
3357
3358  out:
3359         mutex_unlock(&ftrace_lock);
3360 }
3361
3362 /* Allocate a return stack for newly created task */
3363 void ftrace_graph_init_task(struct task_struct *t)
3364 {
3365         /* Make sure we do not use the parent ret_stack */
3366         t->ret_stack = NULL;
3367
3368         if (ftrace_graph_active) {
3369                 struct ftrace_ret_stack *ret_stack;
3370
3371                 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
3372                                 * sizeof(struct ftrace_ret_stack),
3373                                 GFP_KERNEL);
3374                 if (!ret_stack)
3375                         return;
3376                 t->curr_ret_stack = -1;
3377                 atomic_set(&t->tracing_graph_pause, 0);
3378                 atomic_set(&t->trace_overrun, 0);
3379                 t->ftrace_timestamp = 0;
3380                 /* make curr_ret_stack visable before we add the ret_stack */
3381                 smp_wmb();
3382                 t->ret_stack = ret_stack;
3383         }
3384 }
3385
3386 void ftrace_graph_exit_task(struct task_struct *t)
3387 {
3388         struct ftrace_ret_stack *ret_stack = t->ret_stack;
3389
3390         t->ret_stack = NULL;
3391         /* NULL must become visible to IRQs before we free it: */
3392         barrier();
3393
3394         kfree(ret_stack);
3395 }
3396
3397 void ftrace_graph_stop(void)
3398 {
3399         ftrace_stop();
3400 }
3401 #endif