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 /*
  64  * ftrace_disabled is set when an anomaly is discovered.
  65  * ftrace_disabled is much stronger than ftrace_enabled.
  66  */
  67 static int ftrace_disabled __read_mostly;
  68
  69 static DEFINE_MUTEX(ftrace_lock);
  70
  71 static struct ftrace_ops ftrace_list_end __read_mostly =
  72 {
  73         .func           = ftrace_stub,
  74 };
  75
  76 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
  77 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
  78 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
  79 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
  80
  81 static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
  82 {
  83         struct ftrace_ops *op = ftrace_list;
  84
  85         /* in case someone actually ports this to alpha! */
  86         read_barrier_depends();
  87
  88         while (op != &ftrace_list_end) {
  89                 /* silly alpha */
  90                 read_barrier_depends();
  91                 op->func(ip, parent_ip);
  92                 op = op->next;
  93         };
  94 }
  95
  96 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
  97 {
  98         if (!test_tsk_trace_trace(current))
  99                 return;
 100
 101         ftrace_pid_function(ip, parent_ip);
 102 }
 103
 104 static void set_ftrace_pid_function(ftrace_func_t func)
 105 {
 106         /* do not set ftrace_pid_function to itself! */
 107         if (func != ftrace_pid_func)
 108                 ftrace_pid_function = func;
 109 }
 110
 111 /**
 112  * clear_ftrace_function - reset the ftrace function
 113  *
 114  * This NULLs the ftrace function and in essence stops
 115  * tracing.  There may be lag
 116  */
 117 void clear_ftrace_function(void)
 118 {
 119         ftrace_trace_function = ftrace_stub;
 120         __ftrace_trace_function = ftrace_stub;
 121         ftrace_pid_function = ftrace_stub;
 122 }
 123
 124 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 125 /*
 126  * For those archs that do not test ftrace_trace_stop in their
 127  * mcount call site, we need to do it from C.
 128  */
 129 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
 130 {
 131         if (function_trace_stop)
 132                 return;
 133
 134         __ftrace_trace_function(ip, parent_ip);
 135 }
 136 #endif
 137
 138 static int __register_ftrace_function(struct ftrace_ops *ops)
 139 {
 140         ops->next = ftrace_list;
 141         /*
 142          * We are entering ops into the ftrace_list but another
 143          * CPU might be walking that list. We need to make sure
 144          * the ops->next pointer is valid before another CPU sees
 145          * the ops pointer included into the ftrace_list.
 146          */
 147         smp_wmb();
 148         ftrace_list = ops;
 149
 150         if (ftrace_enabled) {
 151                 ftrace_func_t func;
 152
 153                 if (ops->next == &ftrace_list_end)
 154                         func = ops->func;
 155                 else
 156                         func = ftrace_list_func;
 157
 158                 if (ftrace_pid_trace) {
 159                         set_ftrace_pid_function(func);
 160                         func = ftrace_pid_func;
 161                 }
 162
 163                 /*
 164                  * For one func, simply call it directly.
 165                  * For more than one func, call the chain.
 166                  */
 167 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 168                 ftrace_trace_function = func;
 169 #else
 170                 __ftrace_trace_function = func;
 171                 ftrace_trace_function = ftrace_test_stop_func;
 172 #endif
 173         }
 174
 175         return 0;
 176 }
 177
 178 static int __unregister_ftrace_function(struct ftrace_ops *ops)
 179 {
 180         struct ftrace_ops **p;
 181
 182         /*
 183          * If we are removing the last function, then simply point
 184          * to the ftrace_stub.
 185          */
 186         if (ftrace_list == ops && ops->next == &ftrace_list_end) {
 187                 ftrace_trace_function = ftrace_stub;
 188                 ftrace_list = &ftrace_list_end;
 189                 return 0;
 190         }
 191
 192         for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
 193                 if (*p == ops)
 194                         break;
 195
 196         if (*p != ops)
 197                 return -1;
 198
 199         *p = (*p)->next;
 200
 201         if (ftrace_enabled) {
 202                 /* If we only have one func left, then call that directly */
 203                 if (ftrace_list->next == &ftrace_list_end) {
 204                         ftrace_func_t func = ftrace_list->func;
 205
 206                         if (ftrace_pid_trace) {
 207                                 set_ftrace_pid_function(func);
 208                                 func = ftrace_pid_func;
 209                         }
 210 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 211                         ftrace_trace_function = func;
 212 #else
 213                         __ftrace_trace_function = func;
 214 #endif
 215                 }
 216         }
 217
 218         return 0;
 219 }
 220
 221 static void ftrace_update_pid_func(void)
 222 {
 223         ftrace_func_t func;
 224
 225         if (ftrace_trace_function == ftrace_stub)
 226                 return;
 227
 228         func = ftrace_trace_function;
 229
 230         if (ftrace_pid_trace) {
 231                 set_ftrace_pid_function(func);
 232                 func = ftrace_pid_func;
 233         } else {
 234                 if (func == ftrace_pid_func)
 235                         func = ftrace_pid_function;
 236         }
 237
 238 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 239         ftrace_trace_function = func;
 240 #else
 241         __ftrace_trace_function = func;
 242 #endif
 243 }
 244
 245 #ifdef CONFIG_FUNCTION_PROFILER
 246 struct ftrace_profile {
 247         struct hlist_node               node;
 248         unsigned long                   ip;
 249         unsigned long                   counter;
 250 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 251         unsigned long long              time;
 252 #endif
 253 };
 254
 255 struct ftrace_profile_page {
 256         struct ftrace_profile_page      *next;
 257         unsigned long                   index;
 258         struct ftrace_profile           records[];
 259 };
 260
 261 struct ftrace_profile_stat {
 262         atomic_t                        disabled;
 263         struct hlist_head               *hash;
 264         struct ftrace_profile_page      *pages;
 265         struct ftrace_profile_page      *start;
 266         struct tracer_stat              stat;
 267 };
 268
 269 #define PROFILE_RECORDS_SIZE                                            \
 270         (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
 271
 272 #define PROFILES_PER_PAGE                                       \
 273         (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
 274
 275 static int ftrace_profile_bits __read_mostly;
 276 static int ftrace_profile_enabled __read_mostly;
 277
 278 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
 279 static DEFINE_MUTEX(ftrace_profile_lock);
 280
 281 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
 282
 283 #define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
 284
 285 static void *
 286 function_stat_next(void *v, int idx)
 287 {
 288         struct ftrace_profile *rec = v;
 289         struct ftrace_profile_page *pg;
 290
 291         pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
 292
 293  again:
 294         rec++;
 295         if ((void *)rec >= (void *)&pg->records[pg->index]) {
 296                 pg = pg->next;
 297                 if (!pg)
 298                         return NULL;
 299                 rec = &pg->records[0];
 300                 if (!rec->counter)
 301                         goto again;
 302         }
 303
 304         return rec;
 305 }
 306
 307 static void *function_stat_start(struct tracer_stat *trace)
 308 {
 309         struct ftrace_profile_stat *stat =
 310                 container_of(trace, struct ftrace_profile_stat, stat);
 311
 312         if (!stat || !stat->start)
 313                 return NULL;
 314
 315         return function_stat_next(&stat->start->records[0], 0);
 316 }
 317
 318 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 319 /* function graph compares on total time */
 320 static int function_stat_cmp(void *p1, void *p2)
 321 {
 322         struct ftrace_profile *a = p1;
 323         struct ftrace_profile *b = p2;
 324
 325         if (a->time < b->time)
 326                 return -1;
 327         if (a->time > b->time)
 328                 return 1;
 329         else
 330                 return 0;
 331 }
 332 #else
 333 /* not function graph compares against hits */
 334 static int function_stat_cmp(void *p1, void *p2)
 335 {
 336         struct ftrace_profile *a = p1;
 337         struct ftrace_profile *b = p2;
 338
 339         if (a->counter < b->counter)
 340                 return -1;
 341         if (a->counter > b->counter)
 342                 return 1;
 343         else
 344                 return 0;
 345 }
 346 #endif
 347
 348 static int function_stat_headers(struct seq_file *m)
 349 {
 350 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 351         seq_printf(m, "  Function                               "
 352                    "Hit    Time            Avg\n"
 353                       "  --------                               "
 354                    "---    ----            ---\n");
 355 #else
 356         seq_printf(m, "  Function                               Hit\n"
 357                       "  --------                               ---\n");
 358 #endif
 359         return 0;
 360 }
 361
 362 static int function_stat_show(struct seq_file *m, void *v)
 363 {
 364         struct ftrace_profile *rec = v;
 365         char str[KSYM_SYMBOL_LEN];
 366 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 367         static DEFINE_MUTEX(mutex);
 368         static struct trace_seq s;
 369         unsigned long long avg;
 370 #endif
 371
 372         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 373         seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);
 374
 375 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 376         seq_printf(m, "    ");
 377         avg = rec->time;
 378         do_div(avg, rec->counter);
 379
 380         mutex_lock(&mutex);
 381         trace_seq_init(&s);
 382         trace_print_graph_duration(rec->time, &s);
 383         trace_seq_puts(&s, "    ");
 384         trace_print_graph_duration(avg, &s);
 385         trace_print_seq(m, &s);
 386         mutex_unlock(&mutex);
 387 #endif
 388         seq_putc(m, '\n');
 389
 390         return 0;
 391 }
 392
 393 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
 394 {
 395         struct ftrace_profile_page *pg;
 396
 397         pg = stat->pages = stat->start;
 398
 399         while (pg) {
 400                 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
 401                 pg->index = 0;
 402                 pg = pg->next;
 403         }
 404
 405         memset(stat->hash, 0,
 406                FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
 407 }
 408
 409 int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
 410 {
 411         struct ftrace_profile_page *pg;
 412         int functions;
 413         int pages;
 414         int i;
 415
 416         /* If we already allocated, do nothing */
 417         if (stat->pages)
 418                 return 0;
 419
 420         stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
 421         if (!stat->pages)
 422                 return -ENOMEM;
 423
 424 #ifdef CONFIG_DYNAMIC_FTRACE
 425         functions = ftrace_update_tot_cnt;
 426 #else
 427         /*
 428          * We do not know the number of functions that exist because
 429          * dynamic tracing is what counts them. With past experience
 430          * we have around 20K functions. That should be more than enough.
 431          * It is highly unlikely we will execute every function in
 432          * the kernel.
 433          */
 434         functions = 20000;
 435 #endif
 436
 437         pg = stat->start = stat->pages;
 438
 439         pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
 440
 441         for (i = 0; i < pages; i++) {
 442                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
 443                 if (!pg->next)
 444                         goto out_free;
 445                 pg = pg->next;
 446         }
 447
 448         return 0;
 449
 450  out_free:
 451         pg = stat->start;
 452         while (pg) {
 453                 unsigned long tmp = (unsigned long)pg;
 454
 455                 pg = pg->next;
 456                 free_page(tmp);
 457         }
 458
 459         free_page((unsigned long)stat->pages);
 460         stat->pages = NULL;
 461         stat->start = NULL;
 462
 463         return -ENOMEM;
 464 }
 465
 466 static int ftrace_profile_init_cpu(int cpu)
 467 {
 468         struct ftrace_profile_stat *stat;
 469         int size;
 470
 471         stat = &per_cpu(ftrace_profile_stats, cpu);
 472
 473         if (stat->hash) {
 474                 /* If the profile is already created, simply reset it */
 475                 ftrace_profile_reset(stat);
 476                 return 0;
 477         }
 478
 479         /*
 480          * We are profiling all functions, but usually only a few thousand
 481          * functions are hit. We'll make a hash of 1024 items.
 482          */
 483         size = FTRACE_PROFILE_HASH_SIZE;
 484
 485         stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
 486
 487         if (!stat->hash)
 488                 return -ENOMEM;
 489
 490         if (!ftrace_profile_bits) {
 491                 size--;
 492
 493                 for (; size; size >>= 1)
 494                         ftrace_profile_bits++;
 495         }
 496
 497         /* Preallocate the function profiling pages */
 498         if (ftrace_profile_pages_init(stat) < 0) {
 499                 kfree(stat->hash);
 500                 stat->hash = NULL;
 501                 return -ENOMEM;
 502         }
 503
 504         return 0;
 505 }
 506
 507 static int ftrace_profile_init(void)
 508 {
 509         int cpu;
 510         int ret = 0;
 511
 512         for_each_online_cpu(cpu) {
 513                 ret = ftrace_profile_init_cpu(cpu);
 514                 if (ret)
 515                         break;
 516         }
 517
 518         return ret;
 519 }
 520
 521 /* interrupts must be disabled */
 522 static struct ftrace_profile *
 523 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
 524 {
 525         struct ftrace_profile *rec;
 526         struct hlist_head *hhd;
 527         struct hlist_node *n;
 528         unsigned long key;
 529
 530         key = hash_long(ip, ftrace_profile_bits);
 531         hhd = &stat->hash[key];
 532
 533         if (hlist_empty(hhd))
 534                 return NULL;
 535
 536         hlist_for_each_entry_rcu(rec, n, hhd, node) {
 537                 if (rec->ip == ip)
 538                         return rec;
 539         }
 540
 541         return NULL;
 542 }
 543
 544 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
 545                                struct ftrace_profile *rec)
 546 {
 547         unsigned long key;
 548
 549         key = hash_long(rec->ip, ftrace_profile_bits);
 550         hlist_add_head_rcu(&rec->node, &stat->hash[key]);
 551 }
 552
 553 /*
 554  * The memory is already allocated, this simply finds a new record to use.
 555  */
 556 static struct ftrace_profile *
 557 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
 558 {
 559         struct ftrace_profile *rec = NULL;
 560
 561         /* prevent recursion (from NMIs) */
 562         if (atomic_inc_return(&stat->disabled) != 1)
 563                 goto out;
 564
 565         /*
 566          * Try to find the function again since an NMI
 567          * could have added it
 568          */
 569         rec = ftrace_find_profiled_func(stat, ip);
 570         if (rec)
 571                 goto out;
 572
 573         if (stat->pages->index == PROFILES_PER_PAGE) {
 574                 if (!stat->pages->next)
 575                         goto out;
 576                 stat->pages = stat->pages->next;
 577         }
 578
 579         rec = &stat->pages->records[stat->pages->index++];
 580         rec->ip = ip;
 581         ftrace_add_profile(stat, rec);
 582
 583  out:
 584         atomic_dec(&stat->disabled);
 585
 586         return rec;
 587 }
 588
 589 static void
 590 function_profile_call(unsigned long ip, unsigned long parent_ip)
 591 {
 592         struct ftrace_profile_stat *stat;
 593         struct ftrace_profile *rec;
 594         unsigned long flags;
 595
 596         if (!ftrace_profile_enabled)
 597                 return;
 598
 599         local_irq_save(flags);
 600
 601         stat = &__get_cpu_var(ftrace_profile_stats);
 602         if (!stat->hash)
 603                 goto out;
 604
 605         rec = ftrace_find_profiled_func(stat, ip);
 606         if (!rec) {
 607                 rec = ftrace_profile_alloc(stat, ip);
 608                 if (!rec)
 609                         goto out;
 610         }
 611
 612         rec->counter++;
 613  out:
 614         local_irq_restore(flags);
 615 }
 616
 617 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 618 static int profile_graph_entry(struct ftrace_graph_ent *trace)
 619 {
 620         function_profile_call(trace->func, 0);
 621         return 1;
 622 }
 623
 624 static void profile_graph_return(struct ftrace_graph_ret *trace)
 625 {
 626         struct ftrace_profile_stat *stat;
 627         unsigned long long calltime;
 628         struct ftrace_profile *rec;
 629         unsigned long flags;
 630
 631         local_irq_save(flags);
 632         stat = &__get_cpu_var(ftrace_profile_stats);
 633         if (!stat->hash)
 634                 goto out;
 635
 636         calltime = trace->rettime - trace->calltime;
 637
 638         if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
 639                 int index;
 640
 641                 index = trace->depth;
 642
 643                 /* Append this call time to the parent time to subtract */
 644                 if (index)
 645                         current->ret_stack[index - 1].subtime += calltime;
 646
 647                 if (current->ret_stack[index].subtime < calltime)
 648                         calltime -= current->ret_stack[index].subtime;
 649                 else
 650                         calltime = 0;
 651         }
 652
 653         rec = ftrace_find_profiled_func(stat, trace->func);
 654         if (rec)
 655                 rec->time += calltime;
 656
 657  out:
 658         local_irq_restore(flags);
 659 }
 660
 661 static int register_ftrace_profiler(void)
 662 {
 663         return register_ftrace_graph(&profile_graph_return,
 664                                      &profile_graph_entry);
 665 }
 666
 667 static void unregister_ftrace_profiler(void)
 668 {
 669         unregister_ftrace_graph();
 670 }
 671 #else
 672 static struct ftrace_ops ftrace_profile_ops __read_mostly =
 673 {
 674         .func           = function_profile_call,
 675 };
 676
 677 static int register_ftrace_profiler(void)
 678 {
 679         return register_ftrace_function(&ftrace_profile_ops);
 680 }
 681
 682 static void unregister_ftrace_profiler(void)
 683 {
 684         unregister_ftrace_function(&ftrace_profile_ops);
 685 }
 686 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 687
 688 static ssize_t
 689 ftrace_profile_write(struct file *filp, const char __user *ubuf,
 690                      size_t cnt, loff_t *ppos)
 691 {
 692         unsigned long val;
 693         char buf[64];           /* big enough to hold a number */
 694         int ret;
 695
 696         if (cnt >= sizeof(buf))
 697                 return -EINVAL;
 698
 699         if (copy_from_user(&buf, ubuf, cnt))
 700                 return -EFAULT;
 701
 702         buf[cnt] = 0;
 703
 704         ret = strict_strtoul(buf, 10, &val);
 705         if (ret < 0)
 706                 return ret;
 707
 708         val = !!val;
 709
 710         mutex_lock(&ftrace_profile_lock);
 711         if (ftrace_profile_enabled ^ val) {
 712                 if (val) {
 713                         ret = ftrace_profile_init();
 714                         if (ret < 0) {
 715                                 cnt = ret;
 716                                 goto out;
 717                         }
 718
 719                         ret = register_ftrace_profiler();
 720                         if (ret < 0) {
 721                                 cnt = ret;
 722                                 goto out;
 723                         }
 724                         ftrace_profile_enabled = 1;
 725                 } else {
 726                         ftrace_profile_enabled = 0;
 727                         unregister_ftrace_profiler();
 728                 }
 729         }
 730  out:
 731         mutex_unlock(&ftrace_profile_lock);
 732
 733         filp->f_pos += cnt;
 734
 735         return cnt;
 736 }
 737
 738 static ssize_t
 739 ftrace_profile_read(struct file *filp, char __user *ubuf,
 740                      size_t cnt, loff_t *ppos)
 741 {
 742         char buf[64];           /* big enough to hold a number */
 743         int r;
 744
 745         r = sprintf(buf, "%u\n", ftrace_profile_enabled);
 746         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 747 }
 748
 749 static const struct file_operations ftrace_profile_fops = {
 750         .open           = tracing_open_generic,
 751         .read           = ftrace_profile_read,
 752         .write          = ftrace_profile_write,
 753 };
 754
 755 /* used to initialize the real stat files */
 756 static struct tracer_stat function_stats __initdata = {
 757         .name           = "functions",
 758         .stat_start     = function_stat_start,
 759         .stat_next      = function_stat_next,
 760         .stat_cmp       = function_stat_cmp,
 761         .stat_headers   = function_stat_headers,
 762         .stat_show      = function_stat_show
 763 };
 764
 765 static void ftrace_profile_debugfs(struct dentry *d_tracer)
 766 {
 767         struct ftrace_profile_stat *stat;
 768         struct dentry *entry;
 769         char *name;
 770         int ret;
 771         int cpu;
 772
 773         for_each_possible_cpu(cpu) {
 774                 stat = &per_cpu(ftrace_profile_stats, cpu);
 775
 776                 /* allocate enough for function name + cpu number */
 777                 name = kmalloc(32, GFP_KERNEL);
 778                 if (!name) {
 779                         /*
 780                          * The files created are permanent, if something happens
 781                          * we still do not free memory.
 782                          */
 783                         kfree(stat);
 784                         WARN(1,
 785                              "Could not allocate stat file for cpu %d\n",
 786                              cpu);
 787                         return;
 788                 }
 789                 stat->stat = function_stats;
 790                 snprintf(name, 32, "function%d", cpu);
 791                 stat->stat.name = name;
 792                 ret = register_stat_tracer(&stat->stat);
 793                 if (ret) {
 794                         WARN(1,
 795                              "Could not register function stat for cpu %d\n",
 796                              cpu);
 797                         kfree(name);
 798                         return;
 799                 }
 800         }
 801
 802         entry = debugfs_create_file("function_profile_enabled", 0644,
 803                                     d_tracer, NULL, &ftrace_profile_fops);
 804         if (!entry)
 805                 pr_warning("Could not create debugfs "
 806                            "'function_profile_enabled' entry\n");
 807 }
 808
 809 #else /* CONFIG_FUNCTION_PROFILER */
 810 static void ftrace_profile_debugfs(struct dentry *d_tracer)
 811 {
 812 }
 813 #endif /* CONFIG_FUNCTION_PROFILER */
 814
 815 /* set when tracing only a pid */
 816 struct pid *ftrace_pid_trace;
 817 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
 818
 819 #ifdef CONFIG_DYNAMIC_FTRACE
 820
 821 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
 822 # error Dynamic ftrace depends on MCOUNT_RECORD
 823 #endif
 824
 825 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
 826
 827 struct ftrace_func_probe {
 828         struct hlist_node       node;
 829         struct ftrace_probe_ops *ops;
 830         unsigned long           flags;
 831         unsigned long           ip;
 832         void                    *data;
 833         struct rcu_head         rcu;
 834 };
 835
 836 enum {
 837         FTRACE_ENABLE_CALLS             = (1 << 0),
 838         FTRACE_DISABLE_CALLS            = (1 << 1),
 839         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 840         FTRACE_ENABLE_MCOUNT            = (1 << 3),
 841         FTRACE_DISABLE_MCOUNT           = (1 << 4),
 842         FTRACE_START_FUNC_RET           = (1 << 5),
 843         FTRACE_STOP_FUNC_RET            = (1 << 6),
 844 };
 845
 846 static int ftrace_filtered;
 847
 848 static struct dyn_ftrace *ftrace_new_addrs;
 849
 850 static DEFINE_MUTEX(ftrace_regex_lock);
 851
 852 struct ftrace_page {
 853         struct ftrace_page      *next;
 854         int                     index;
 855         struct dyn_ftrace       records[];
 856 };
 857
 858 #define ENTRIES_PER_PAGE \
 859   ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
 860
 861 /* estimate from running different kernels */
 862 #define NR_TO_INIT              10000
 863
 864 static struct ftrace_page       *ftrace_pages_start;
 865 static struct ftrace_page       *ftrace_pages;
 866
 867 static struct dyn_ftrace *ftrace_free_records;
 868
 869 /*
 870  * This is a double for. Do not use 'break' to break out of the loop,
 871  * you must use a goto.
 872  */
 873 #define do_for_each_ftrace_rec(pg, rec)                                 \
 874         for (pg = ftrace_pages_start; pg; pg = pg->next) {              \
 875                 int _____i;                                             \
 876                 for (_____i = 0; _____i < pg->index; _____i++) {        \
 877                         rec = &pg->records[_____i];
 878
 879 #define while_for_each_ftrace_rec()             \
 880                 }                               \
 881         }
 882
 883 #ifdef CONFIG_KPROBES
 884
 885 static int frozen_record_count;
 886
 887 static inline void freeze_record(struct dyn_ftrace *rec)
 888 {
 889         if (!(rec->flags & FTRACE_FL_FROZEN)) {
 890                 rec->flags |= FTRACE_FL_FROZEN;
 891                 frozen_record_count++;
 892         }
 893 }
 894
 895 static inline void unfreeze_record(struct dyn_ftrace *rec)
 896 {
 897         if (rec->flags & FTRACE_FL_FROZEN) {
 898                 rec->flags &= ~FTRACE_FL_FROZEN;
 899                 frozen_record_count--;
 900         }
 901 }
 902
 903 static inline int record_frozen(struct dyn_ftrace *rec)
 904 {
 905         return rec->flags & FTRACE_FL_FROZEN;
 906 }
 907 #else
 908 # define freeze_record(rec)                     ({ 0; })
 909 # define unfreeze_record(rec)                   ({ 0; })
 910 # define record_frozen(rec)                     ({ 0; })
 911 #endif /* CONFIG_KPROBES */
 912
 913 static void ftrace_free_rec(struct dyn_ftrace *rec)
 914 {
 915         rec->freelist = ftrace_free_records;
 916         ftrace_free_records = rec;
 917         rec->flags |= FTRACE_FL_FREE;
 918 }
 919
 920 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
 921 {
 922         struct dyn_ftrace *rec;
 923
 924         /* First check for freed records */
 925         if (ftrace_free_records) {
 926                 rec = ftrace_free_records;
 927
 928                 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
 929                         FTRACE_WARN_ON_ONCE(1);
 930                         ftrace_free_records = NULL;
 931                         return NULL;
 932                 }
 933
 934                 ftrace_free_records = rec->freelist;
 935                 memset(rec, 0, sizeof(*rec));
 936                 return rec;
 937         }
 938
 939         if (ftrace_pages->index == ENTRIES_PER_PAGE) {
 940                 if (!ftrace_pages->next) {
 941                         /* allocate another page */
 942                         ftrace_pages->next =
 943                                 (void *)get_zeroed_page(GFP_KERNEL);
 944                         if (!ftrace_pages->next)
 945                                 return NULL;
 946                 }
 947                 ftrace_pages = ftrace_pages->next;
 948         }
 949
 950         return &ftrace_pages->records[ftrace_pages->index++];
 951 }
 952
 953 static struct dyn_ftrace *
 954 ftrace_record_ip(unsigned long ip)
 955 {
 956         struct dyn_ftrace *rec;
 957
 958         if (ftrace_disabled)
 959                 return NULL;
 960
 961         rec = ftrace_alloc_dyn_node(ip);
 962         if (!rec)
 963                 return NULL;
 964
 965         rec->ip = ip;
 966         rec->newlist = ftrace_new_addrs;
 967         ftrace_new_addrs = rec;
 968
 969         return rec;
 970 }
 971
 972 static void print_ip_ins(const char *fmt, unsigned char *p)
 973 {
 974         int i;
 975
 976         printk(KERN_CONT "%s", fmt);
 977
 978         for (i = 0; i < MCOUNT_INSN_SIZE; i++)
 979                 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
 980 }
 981
 982 static void ftrace_bug(int failed, unsigned long ip)
 983 {
 984         switch (failed) {
 985         case -EFAULT:
 986                 FTRACE_WARN_ON_ONCE(1);
 987                 pr_info("ftrace faulted on modifying ");
 988                 print_ip_sym(ip);
 989                 break;
 990         case -EINVAL:
 991                 FTRACE_WARN_ON_ONCE(1);
 992                 pr_info("ftrace failed to modify ");
 993                 print_ip_sym(ip);
 994                 print_ip_ins(" actual: ", (unsigned char *)ip);
 995                 printk(KERN_CONT "\n");
 996                 break;
 997         case -EPERM:
 998                 FTRACE_WARN_ON_ONCE(1);
 999                 pr_info("ftrace faulted on writing ");
1000                 print_ip_sym(ip);
1001                 break;
1002         default:
1003                 FTRACE_WARN_ON_ONCE(1);
1004                 pr_info("ftrace faulted on unknown error ");
1005                 print_ip_sym(ip);
1006         }
1007 }
1008
1009
1010 static int
1011 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1012 {
1013         unsigned long ftrace_addr;
1014         unsigned long ip, fl;
1015
1016         ftrace_addr = (unsigned long)FTRACE_ADDR;
1017
1018         ip = rec->ip;
1019
1020         /*
1021          * If this record is not to be traced and
1022          * it is not enabled then do nothing.
1023          *
1024          * If this record is not to be traced and
1025          * it is enabled then disable it.
1026          *
1027          */
1028         if (rec->flags & FTRACE_FL_NOTRACE) {
1029                 if (rec->flags & FTRACE_FL_ENABLED)
1030                         rec->flags &= ~FTRACE_FL_ENABLED;
1031                 else
1032                         return 0;
1033
1034         } else if (ftrace_filtered && enable) {
1035                 /*
1036                  * Filtering is on:
1037                  */
1038
1039                 fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED);
1040
1041                 /* Record is filtered and enabled, do nothing */
1042                 if (fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED))
1043                         return 0;
1044
1045                 /* Record is not filtered or enabled, do nothing */
1046                 if (!fl)
1047                         return 0;
1048
1049                 /* Record is not filtered but enabled, disable it */
1050                 if (fl == FTRACE_FL_ENABLED)
1051                         rec->flags &= ~FTRACE_FL_ENABLED;
1052                 else
1053                 /* Otherwise record is filtered but not enabled, enable it */
1054                         rec->flags |= FTRACE_FL_ENABLED;
1055         } else {
1056                 /* Disable or not filtered */
1057
1058                 if (enable) {
1059                         /* if record is enabled, do nothing */
1060                         if (rec->flags & FTRACE_FL_ENABLED)
1061                                 return 0;
1062
1063                         rec->flags |= FTRACE_FL_ENABLED;
1064
1065                 } else {
1066
1067                         /* if record is not enabled, do nothing */
1068                         if (!(rec->flags & FTRACE_FL_ENABLED))
1069                                 return 0;
1070
1071                         rec->flags &= ~FTRACE_FL_ENABLED;
1072                 }
1073         }
1074
1075         if (rec->flags & FTRACE_FL_ENABLED)
1076                 return ftrace_make_call(rec, ftrace_addr);
1077         else
1078                 return ftrace_make_nop(NULL, rec, ftrace_addr);
1079 }
1080
1081 static void ftrace_replace_code(int enable)
1082 {
1083         struct dyn_ftrace *rec;
1084         struct ftrace_page *pg;
1085         int failed;
1086
1087         do_for_each_ftrace_rec(pg, rec) {
1088                 /*
1089                  * Skip over free records, records that have
1090                  * failed and not converted.
1091                  */
1092                 if (rec->flags & FTRACE_FL_FREE ||
1093                     rec->flags & FTRACE_FL_FAILED ||
1094                     !(rec->flags & FTRACE_FL_CONVERTED))
1095                         continue;
1096
1097                 /* ignore updates to this record's mcount site */
1098                 if (get_kprobe((void *)rec->ip)) {
1099                         freeze_record(rec);
1100                         continue;
1101                 } else {
1102                         unfreeze_record(rec);
1103                 }
1104
1105                 failed = __ftrace_replace_code(rec, enable);
1106                 if (failed) {
1107                         rec->flags |= FTRACE_FL_FAILED;
1108                         if ((system_state == SYSTEM_BOOTING) ||
1109                             !core_kernel_text(rec->ip)) {
1110                                 ftrace_free_rec(rec);
1111                                 } else {
1112                                 ftrace_bug(failed, rec->ip);
1113                                         /* Stop processing */
1114                                         return;
1115                                 }
1116                 }
1117         } while_for_each_ftrace_rec();
1118 }
1119
1120 static int
1121 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1122 {
1123         unsigned long ip;
1124         int ret;
1125
1126         ip = rec->ip;
1127
1128         ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1129         if (ret) {
1130                 ftrace_bug(ret, ip);
1131                 rec->flags |= FTRACE_FL_FAILED;
1132                 return 0;
1133         }
1134         return 1;
1135 }
1136
1137 /*
1138  * archs can override this function if they must do something
1139  * before the modifying code is performed.
1140  */
1141 int __weak ftrace_arch_code_modify_prepare(void)
1142 {
1143         return 0;
1144 }
1145
1146 /*
1147  * archs can override this function if they must do something
1148  * after the modifying code is performed.
1149  */
1150 int __weak ftrace_arch_code_modify_post_process(void)
1151 {
1152         return 0;
1153 }
1154
1155 static int __ftrace_modify_code(void *data)
1156 {
1157         int *command = data;
1158
1159         if (*command & FTRACE_ENABLE_CALLS)
1160                 ftrace_replace_code(1);
1161         else if (*command & FTRACE_DISABLE_CALLS)
1162                 ftrace_replace_code(0);
1163
1164         if (*command & FTRACE_UPDATE_TRACE_FUNC)
1165                 ftrace_update_ftrace_func(ftrace_trace_function);
1166
1167         if (*command & FTRACE_START_FUNC_RET)
1168                 ftrace_enable_ftrace_graph_caller();
1169         else if (*command & FTRACE_STOP_FUNC_RET)
1170                 ftrace_disable_ftrace_graph_caller();
1171
1172         return 0;
1173 }
1174
1175 static void ftrace_run_update_code(int command)
1176 {
1177         int ret;
1178
1179         ret = ftrace_arch_code_modify_prepare();
1180         FTRACE_WARN_ON(ret);
1181         if (ret)
1182                 return;
1183
1184         stop_machine(__ftrace_modify_code, &command, NULL);
1185
1186         ret = ftrace_arch_code_modify_post_process();
1187         FTRACE_WARN_ON(ret);
1188 }
1189
1190 static ftrace_func_t saved_ftrace_func;
1191 static int ftrace_start_up;
1192
1193 static void ftrace_startup_enable(int command)
1194 {
1195         if (saved_ftrace_func != ftrace_trace_function) {
1196                 saved_ftrace_func = ftrace_trace_function;
1197                 command |= FTRACE_UPDATE_TRACE_FUNC;
1198         }
1199
1200         if (!command || !ftrace_enabled)
1201                 return;
1202
1203         ftrace_run_update_code(command);
1204 }
1205
1206 static void ftrace_startup(int command)
1207 {
1208         if (unlikely(ftrace_disabled))
1209                 return;
1210
1211         ftrace_start_up++;
1212         command |= FTRACE_ENABLE_CALLS;
1213
1214         ftrace_startup_enable(command);
1215 }
1216
1217 static void ftrace_shutdown(int command)
1218 {
1219         if (unlikely(ftrace_disabled))
1220                 return;
1221
1222         ftrace_start_up--;
1223         if (!ftrace_start_up)
1224                 command |= FTRACE_DISABLE_CALLS;
1225
1226         if (saved_ftrace_func != ftrace_trace_function) {
1227                 saved_ftrace_func = ftrace_trace_function;
1228                 command |= FTRACE_UPDATE_TRACE_FUNC;
1229         }
1230
1231         if (!command || !ftrace_enabled)
1232                 return;
1233
1234         ftrace_run_update_code(command);
1235 }
1236
1237 static void ftrace_startup_sysctl(void)
1238 {
1239         int command = FTRACE_ENABLE_MCOUNT;
1240
1241         if (unlikely(ftrace_disabled))
1242                 return;
1243
1244         /* Force update next time */
1245         saved_ftrace_func = NULL;
1246         /* ftrace_start_up is true if we want ftrace running */
1247         if (ftrace_start_up)
1248                 command |= FTRACE_ENABLE_CALLS;
1249
1250         ftrace_run_update_code(command);
1251 }
1252
1253 static void ftrace_shutdown_sysctl(void)
1254 {
1255         int command = FTRACE_DISABLE_MCOUNT;
1256
1257         if (unlikely(ftrace_disabled))
1258                 return;
1259
1260         /* ftrace_start_up is true if ftrace is running */
1261         if (ftrace_start_up)
1262                 command |= FTRACE_DISABLE_CALLS;
1263
1264         ftrace_run_update_code(command);
1265 }
1266
1267 static cycle_t          ftrace_update_time;
1268 static unsigned long    ftrace_update_cnt;
1269 unsigned long           ftrace_update_tot_cnt;
1270
1271 static int ftrace_update_code(struct module *mod)
1272 {
1273         struct dyn_ftrace *p;
1274         cycle_t start, stop;
1275
1276         start = ftrace_now(raw_smp_processor_id());
1277         ftrace_update_cnt = 0;
1278
1279         while (ftrace_new_addrs) {
1280
1281                 /* If something went wrong, bail without enabling anything */
1282                 if (unlikely(ftrace_disabled))
1283                         return -1;
1284
1285                 p = ftrace_new_addrs;
1286                 ftrace_new_addrs = p->newlist;
1287                 p->flags = 0L;
1288
1289                 /* convert record (i.e, patch mcount-call with NOP) */
1290                 if (ftrace_code_disable(mod, p)) {
1291                         p->flags |= FTRACE_FL_CONVERTED;
1292                         ftrace_update_cnt++;
1293                 } else
1294                         ftrace_free_rec(p);
1295         }
1296
1297         stop = ftrace_now(raw_smp_processor_id());
1298         ftrace_update_time = stop - start;
1299         ftrace_update_tot_cnt += ftrace_update_cnt;
1300
1301         return 0;
1302 }
1303
1304 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
1305 {
1306         struct ftrace_page *pg;
1307         int cnt;
1308         int i;
1309
1310         /* allocate a few pages */
1311         ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
1312         if (!ftrace_pages_start)
1313                 return -1;
1314
1315         /*
1316          * Allocate a few more pages.
1317          *
1318          * TODO: have some parser search vmlinux before
1319          *   final linking to find all calls to ftrace.
1320          *   Then we can:
1321          *    a) know how many pages to allocate.
1322          *     and/or
1323          *    b) set up the table then.
1324          *
1325          *  The dynamic code is still necessary for
1326          *  modules.
1327          */
1328
1329         pg = ftrace_pages = ftrace_pages_start;
1330
1331         cnt = num_to_init / ENTRIES_PER_PAGE;
1332         pr_info("ftrace: allocating %ld entries in %d pages\n",
1333                 num_to_init, cnt + 1);
1334
1335         for (i = 0; i < cnt; i++) {
1336                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
1337
1338                 /* If we fail, we'll try later anyway */
1339                 if (!pg->next)
1340                         break;
1341
1342                 pg = pg->next;
1343         }
1344
1345         return 0;
1346 }
1347
1348 enum {
1349         FTRACE_ITER_FILTER      = (1 << 0),
1350         FTRACE_ITER_CONT        = (1 << 1),
1351         FTRACE_ITER_NOTRACE     = (1 << 2),
1352         FTRACE_ITER_FAILURES    = (1 << 3),
1353         FTRACE_ITER_PRINTALL    = (1 << 4),
1354         FTRACE_ITER_HASH        = (1 << 5),
1355 };
1356
1357 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1358
1359 struct ftrace_iterator {
1360         struct ftrace_page      *pg;
1361         int                     hidx;
1362         int                     idx;
1363         unsigned                flags;
1364         unsigned char           buffer[FTRACE_BUFF_MAX+1];
1365         unsigned                buffer_idx;
1366         unsigned                filtered;
1367 };
1368
1369 static void *
1370 t_hash_next(struct seq_file *m, void *v, loff_t *pos)
1371 {
1372         struct ftrace_iterator *iter = m->private;
1373         struct hlist_node *hnd = v;
1374         struct hlist_head *hhd;
1375
1376         WARN_ON(!(iter->flags & FTRACE_ITER_HASH));
1377
1378         (*pos)++;
1379
1380  retry:
1381         if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
1382                 return NULL;
1383
1384         hhd = &ftrace_func_hash[iter->hidx];
1385
1386         if (hlist_empty(hhd)) {
1387                 iter->hidx++;
1388                 hnd = NULL;
1389                 goto retry;
1390         }
1391
1392         if (!hnd)
1393                 hnd = hhd->first;
1394         else {
1395                 hnd = hnd->next;
1396                 if (!hnd) {
1397                         iter->hidx++;
1398                         goto retry;
1399                 }
1400         }
1401
1402         return hnd;
1403 }
1404
1405 static void *t_hash_start(struct seq_file *m, loff_t *pos)
1406 {
1407         struct ftrace_iterator *iter = m->private;
1408         void *p = NULL;
1409
1410         iter->flags |= FTRACE_ITER_HASH;
1411
1412         return t_hash_next(m, p, pos);
1413 }
1414
1415 static int t_hash_show(struct seq_file *m, void *v)
1416 {
1417         struct ftrace_func_probe *rec;
1418         struct hlist_node *hnd = v;
1419         char str[KSYM_SYMBOL_LEN];
1420
1421         rec = hlist_entry(hnd, struct ftrace_func_probe, node);
1422
1423         if (rec->ops->print)
1424                 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
1425
1426         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1427         seq_printf(m, "%s:", str);
1428
1429         kallsyms_lookup((unsigned long)rec->ops->func, NULL, NULL, NULL, str);
1430         seq_printf(m, "%s", str);
1431
1432         if (rec->data)
1433                 seq_printf(m, ":%p", rec->data);
1434         seq_putc(m, '\n');
1435
1436         return 0;
1437 }
1438
1439 static void *
1440 t_next(struct seq_file *m, void *v, loff_t *pos)
1441 {
1442         struct ftrace_iterator *iter = m->private;
1443         struct dyn_ftrace *rec = NULL;
1444
1445         if (iter->flags & FTRACE_ITER_HASH)
1446                 return t_hash_next(m, v, pos);
1447
1448         (*pos)++;
1449
1450         if (iter->flags & FTRACE_ITER_PRINTALL)
1451                 return NULL;
1452
1453  retry:
1454         if (iter->idx >= iter->pg->index) {
1455                 if (iter->pg->next) {
1456                         iter->pg = iter->pg->next;
1457                         iter->idx = 0;
1458                         goto retry;
1459                 } else {
1460                         iter->idx = -1;
1461                 }
1462         } else {
1463                 rec = &iter->pg->records[iter->idx++];
1464                 if ((rec->flags & FTRACE_FL_FREE) ||
1465
1466                     (!(iter->flags & FTRACE_ITER_FAILURES) &&
1467                      (rec->flags & FTRACE_FL_FAILED)) ||
1468
1469                     ((iter->flags & FTRACE_ITER_FAILURES) &&
1470                      !(rec->flags & FTRACE_FL_FAILED)) ||
1471
1472                     ((iter->flags & FTRACE_ITER_FILTER) &&
1473                      !(rec->flags & FTRACE_FL_FILTER)) ||
1474
1475                     ((iter->flags & FTRACE_ITER_NOTRACE) &&
1476                      !(rec->flags & FTRACE_FL_NOTRACE))) {
1477                         rec = NULL;
1478                         goto retry;
1479                 }
1480         }
1481
1482         return rec;
1483 }
1484
1485 static void *t_start(struct seq_file *m, loff_t *pos)
1486 {
1487         struct ftrace_iterator *iter = m->private;
1488         void *p = NULL;
1489
1490         mutex_lock(&ftrace_lock);
1491         /*
1492          * For set_ftrace_filter reading, if we have the filter
1493          * off, we can short cut and just print out that all
1494          * functions are enabled.
1495          */
1496         if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) {
1497                 if (*pos > 0)
1498                         return t_hash_start(m, pos);
1499                 iter->flags |= FTRACE_ITER_PRINTALL;
1500                 (*pos)++;
1501                 return iter;
1502         }
1503
1504         if (iter->flags & FTRACE_ITER_HASH)
1505                 return t_hash_start(m, pos);
1506
1507         if (*pos > 0) {
1508                 if (iter->idx < 0)
1509                         return p;
1510                 (*pos)--;
1511                 iter->idx--;
1512         }
1513
1514         p = t_next(m, p, pos);
1515
1516         if (!p)
1517                 return t_hash_start(m, pos);
1518
1519         return p;
1520 }
1521
1522 static void t_stop(struct seq_file *m, void *p)
1523 {
1524         mutex_unlock(&ftrace_lock);
1525 }
1526
1527 static int t_show(struct seq_file *m, void *v)
1528 {
1529         struct ftrace_iterator *iter = m->private;
1530         struct dyn_ftrace *rec = v;
1531         char str[KSYM_SYMBOL_LEN];
1532
1533         if (iter->flags & FTRACE_ITER_HASH)
1534                 return t_hash_show(m, v);
1535
1536         if (iter->flags & FTRACE_ITER_PRINTALL) {
1537                 seq_printf(m, "#### all functions enabled ####\n");
1538                 return 0;
1539         }
1540
1541         if (!rec)
1542                 return 0;
1543
1544         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1545
1546         seq_printf(m, "%s\n", str);
1547
1548         return 0;
1549 }
1550
1551 static struct seq_operations show_ftrace_seq_ops = {
1552         .start = t_start,
1553         .next = t_next,
1554         .stop = t_stop,
1555         .show = t_show,
1556 };
1557
1558 static int
1559 ftrace_avail_open(struct inode *inode, struct file *file)
1560 {
1561         struct ftrace_iterator *iter;
1562         int ret;
1563
1564         if (unlikely(ftrace_disabled))
1565                 return -ENODEV;
1566
1567         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1568         if (!iter)
1569                 return -ENOMEM;
1570
1571         iter->pg = ftrace_pages_start;
1572
1573         ret = seq_open(file, &show_ftrace_seq_ops);
1574         if (!ret) {
1575                 struct seq_file *m = file->private_data;
1576
1577                 m->private = iter;
1578         } else {
1579                 kfree(iter);
1580         }
1581
1582         return ret;
1583 }
1584
1585 int ftrace_avail_release(struct inode *inode, struct file *file)
1586 {
1587         struct seq_file *m = (struct seq_file *)file->private_data;
1588         struct ftrace_iterator *iter = m->private;
1589
1590         seq_release(inode, file);
1591         kfree(iter);
1592
1593         return 0;
1594 }
1595
1596 static int
1597 ftrace_failures_open(struct inode *inode, struct file *file)
1598 {
1599         int ret;
1600         struct seq_file *m;
1601         struct ftrace_iterator *iter;
1602
1603         ret = ftrace_avail_open(inode, file);
1604         if (!ret) {
1605                 m = (struct seq_file *)file->private_data;
1606                 iter = (struct ftrace_iterator *)m->private;
1607                 iter->flags = FTRACE_ITER_FAILURES;
1608         }
1609
1610         return ret;
1611 }
1612
1613
1614 static void ftrace_filter_reset(int enable)
1615 {
1616         struct ftrace_page *pg;
1617         struct dyn_ftrace *rec;
1618         unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1619
1620         mutex_lock(&ftrace_lock);
1621         if (enable)
1622                 ftrace_filtered = 0;
1623         do_for_each_ftrace_rec(pg, rec) {
1624                 if (rec->flags & FTRACE_FL_FAILED)
1625                         continue;
1626                 rec->flags &= ~type;
1627         } while_for_each_ftrace_rec();
1628         mutex_unlock(&ftrace_lock);
1629 }
1630
1631 static int
1632 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
1633 {
1634         struct ftrace_iterator *iter;
1635         int ret = 0;
1636
1637         if (unlikely(ftrace_disabled))
1638                 return -ENODEV;
1639
1640         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1641         if (!iter)
1642                 return -ENOMEM;
1643
1644         mutex_lock(&ftrace_regex_lock);
1645         if ((file->f_mode & FMODE_WRITE) &&
1646             !(file->f_flags & O_APPEND))
1647                 ftrace_filter_reset(enable);
1648
1649         if (file->f_mode & FMODE_READ) {
1650                 iter->pg = ftrace_pages_start;
1651                 iter->flags = enable ? FTRACE_ITER_FILTER :
1652                         FTRACE_ITER_NOTRACE;
1653
1654                 ret = seq_open(file, &show_ftrace_seq_ops);
1655                 if (!ret) {
1656                         struct seq_file *m = file->private_data;
1657                         m->private = iter;
1658                 } else
1659                         kfree(iter);
1660         } else
1661                 file->private_data = iter;
1662         mutex_unlock(&ftrace_regex_lock);
1663
1664         return ret;
1665 }
1666
1667 static int
1668 ftrace_filter_open(struct inode *inode, struct file *file)
1669 {
1670         return ftrace_regex_open(inode, file, 1);
1671 }
1672
1673 static int
1674 ftrace_notrace_open(struct inode *inode, struct file *file)
1675 {
1676         return ftrace_regex_open(inode, file, 0);
1677 }
1678
1679 static loff_t
1680 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1681 {
1682         loff_t ret;
1683
1684         if (file->f_mode & FMODE_READ)
1685                 ret = seq_lseek(file, offset, origin);
1686         else
1687                 file->f_pos = ret = 1;
1688
1689         return ret;
1690 }
1691
1692 enum {
1693         MATCH_FULL,
1694         MATCH_FRONT_ONLY,
1695         MATCH_MIDDLE_ONLY,
1696         MATCH_END_ONLY,
1697 };
1698
1699 /*
1700  * (static function - no need for kernel doc)
1701  *
1702  * Pass in a buffer containing a glob and this function will
1703  * set search to point to the search part of the buffer and
1704  * return the type of search it is (see enum above).
1705  * This does modify buff.
1706  *
1707  * Returns enum type.
1708  *  search returns the pointer to use for comparison.
1709  *  not returns 1 if buff started with a '!'
1710  *     0 otherwise.
1711  */
1712 static int
1713 ftrace_setup_glob(char *buff, int len, char **search, int *not)
1714 {
1715         int type = MATCH_FULL;
1716         int i;
1717
1718         if (buff[0] == '!') {
1719                 *not = 1;
1720                 buff++;
1721                 len--;
1722         } else
1723                 *not = 0;
1724
1725         *search = buff;
1726
1727         for (i = 0; i < len; i++) {
1728                 if (buff[i] == '*') {
1729                         if (!i) {
1730                                 *search = buff + 1;
1731                                 type = MATCH_END_ONLY;
1732                         } else {
1733                                 if (type == MATCH_END_ONLY)
1734                                         type = MATCH_MIDDLE_ONLY;
1735                                 else
1736                                         type = MATCH_FRONT_ONLY;
1737                                 buff[i] = 0;
1738                                 break;
1739                         }
1740                 }
1741         }
1742
1743         return type;
1744 }
1745
1746 static int ftrace_match(char *str, char *regex, int len, int type)
1747 {
1748         int matched = 0;
1749         char *ptr;
1750
1751         switch (type) {
1752         case MATCH_FULL:
1753                 if (strcmp(str, regex) == 0)
1754                         matched = 1;
1755                 break;
1756         case MATCH_FRONT_ONLY:
1757                 if (strncmp(str, regex, len) == 0)
1758                         matched = 1;
1759                 break;
1760         case MATCH_MIDDLE_ONLY:
1761                 if (strstr(str, regex))
1762                         matched = 1;
1763                 break;
1764         case MATCH_END_ONLY:
1765                 ptr = strstr(str, regex);
1766                 if (ptr && (ptr[len] == 0))
1767                         matched = 1;
1768                 break;
1769         }
1770
1771         return matched;
1772 }
1773
1774 static int
1775 ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
1776 {
1777         char str[KSYM_SYMBOL_LEN];
1778
1779         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1780         return ftrace_match(str, regex, len, type);
1781 }
1782
1783 static void ftrace_match_records(char *buff, int len, int enable)
1784 {
1785         unsigned int search_len;
1786         struct ftrace_page *pg;
1787         struct dyn_ftrace *rec;
1788         unsigned long flag;
1789         char *search;
1790         int type;
1791         int not;
1792
1793         flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1794         type = ftrace_setup_glob(buff, len, &search, &not);
1795
1796         search_len = strlen(search);
1797
1798         mutex_lock(&ftrace_lock);
1799         do_for_each_ftrace_rec(pg, rec) {
1800
1801                 if (rec->flags & FTRACE_FL_FAILED)
1802                         continue;
1803
1804                 if (ftrace_match_record(rec, search, search_len, type)) {
1805                         if (not)
1806                                 rec->flags &= ~flag;
1807                         else
1808                                 rec->flags |= flag;
1809                 }
1810                 /*
1811                  * Only enable filtering if we have a function that
1812                  * is filtered on.
1813                  */
1814                 if (enable && (rec->flags & FTRACE_FL_FILTER))
1815                         ftrace_filtered = 1;
1816         } while_for_each_ftrace_rec();
1817         mutex_unlock(&ftrace_lock);
1818 }
1819
1820 static int
1821 ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
1822                            char *regex, int len, int type)
1823 {
1824         char str[KSYM_SYMBOL_LEN];
1825         char *modname;
1826
1827         kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
1828
1829         if (!modname || strcmp(modname, mod))
1830                 return 0;
1831
1832         /* blank search means to match all funcs in the mod */
1833         if (len)
1834                 return ftrace_match(str, regex, len, type);
1835         else
1836                 return 1;
1837 }
1838
1839 static void ftrace_match_module_records(char *buff, char *mod, int enable)
1840 {
1841         unsigned search_len = 0;
1842         struct ftrace_page *pg;
1843         struct dyn_ftrace *rec;
1844         int type = MATCH_FULL;
1845         char *search = buff;
1846         unsigned long flag;
1847         int not = 0;
1848
1849         flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1850
1851         /* blank or '*' mean the same */
1852         if (strcmp(buff, "*") == 0)
1853                 buff[0] = 0;
1854
1855         /* handle the case of 'dont filter this module' */
1856         if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
1857                 buff[0] = 0;
1858                 not = 1;
1859         }
1860
1861         if (strlen(buff)) {
1862                 type = ftrace_setup_glob(buff, strlen(buff), &search, &not);
1863                 search_len = strlen(search);
1864         }
1865
1866         mutex_lock(&ftrace_lock);
1867         do_for_each_ftrace_rec(pg, rec) {
1868
1869                 if (rec->flags & FTRACE_FL_FAILED)
1870                         continue;
1871
1872                 if (ftrace_match_module_record(rec, mod,
1873                                                search, search_len, type)) {
1874                         if (not)
1875                                 rec->flags &= ~flag;
1876                         else
1877                                 rec->flags |= flag;
1878                 }
1879                 if (enable && (rec->flags & FTRACE_FL_FILTER))
1880                         ftrace_filtered = 1;
1881
1882         } while_for_each_ftrace_rec();
1883         mutex_unlock(&ftrace_lock);
1884 }
1885
1886 /*
1887  * We register the module command as a template to show others how
1888  * to register the a command as well.
1889  */
1890
1891 static int
1892 ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
1893 {
1894         char *mod;
1895
1896         /*
1897          * cmd == 'mod' because we only registered this func
1898          * for the 'mod' ftrace_func_command.
1899          * But if you register one func with multiple commands,
1900          * you can tell which command was used by the cmd
1901          * parameter.
1902          */
1903
1904         /* we must have a module name */
1905         if (!param)
1906                 return -EINVAL;
1907
1908         mod = strsep(&param, ":");
1909         if (!strlen(mod))
1910                 return -EINVAL;
1911
1912         ftrace_match_module_records(func, mod, enable);
1913         return 0;
1914 }
1915
1916 static struct ftrace_func_command ftrace_mod_cmd = {
1917         .name                   = "mod",
1918         .func                   = ftrace_mod_callback,
1919 };
1920
1921 static int __init ftrace_mod_cmd_init(void)
1922 {
1923         return register_ftrace_command(&ftrace_mod_cmd);
1924 }
1925 device_initcall(ftrace_mod_cmd_init);
1926
1927 static void
1928 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
1929 {
1930         struct ftrace_func_probe *entry;
1931         struct hlist_head *hhd;
1932         struct hlist_node *n;
1933         unsigned long key;
1934         int resched;
1935
1936         key = hash_long(ip, FTRACE_HASH_BITS);
1937
1938         hhd = &ftrace_func_hash[key];
1939
1940         if (hlist_empty(hhd))
1941                 return;
1942
1943         /*
1944          * Disable preemption for these calls to prevent a RCU grace
1945          * period. This syncs the hash iteration and freeing of items
1946          * on the hash. rcu_read_lock is too dangerous here.
1947          */
1948         resched = ftrace_preempt_disable();
1949         hlist_for_each_entry_rcu(entry, n, hhd, node) {
1950                 if (entry->ip == ip)
1951                         entry->ops->func(ip, parent_ip, &entry->data);
1952         }
1953         ftrace_preempt_enable(resched);
1954 }
1955
1956 static struct ftrace_ops trace_probe_ops __read_mostly =
1957 {
1958         .func           = function_trace_probe_call,
1959 };
1960
1961 static int ftrace_probe_registered;
1962
1963 static void __enable_ftrace_function_probe(void)
1964 {
1965         int i;
1966
1967         if (ftrace_probe_registered)
1968                 return;
1969
1970         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1971                 struct hlist_head *hhd = &ftrace_func_hash[i];
1972                 if (hhd->first)
1973                         break;
1974         }
1975         /* Nothing registered? */
1976         if (i == FTRACE_FUNC_HASHSIZE)
1977                 return;
1978
1979         __register_ftrace_function(&trace_probe_ops);
1980         ftrace_startup(0);
1981         ftrace_probe_registered = 1;
1982 }
1983
1984 static void __disable_ftrace_function_probe(void)
1985 {
1986         int i;
1987
1988         if (!ftrace_probe_registered)
1989                 return;
1990
1991         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1992                 struct hlist_head *hhd = &ftrace_func_hash[i];
1993                 if (hhd->first)
1994                         return;
1995         }
1996
1997         /* no more funcs left */
1998         __unregister_ftrace_function(&trace_probe_ops);
1999         ftrace_shutdown(0);
2000         ftrace_probe_registered = 0;
2001 }
2002
2003
2004 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
2005 {
2006         struct ftrace_func_probe *entry =
2007                 container_of(rhp, struct ftrace_func_probe, rcu);
2008
2009         if (entry->ops->free)
2010                 entry->ops->free(&entry->data);
2011         kfree(entry);
2012 }
2013
2014
2015 int
2016 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2017                               void *data)
2018 {
2019         struct ftrace_func_probe *entry;
2020         struct ftrace_page *pg;
2021         struct dyn_ftrace *rec;
2022         int type, len, not;
2023         unsigned long key;
2024         int count = 0;
2025         char *search;
2026
2027         type = ftrace_setup_glob(glob, strlen(glob), &search, &not);
2028         len = strlen(search);
2029
2030         /* we do not support '!' for function probes */
2031         if (WARN_ON(not))
2032                 return -EINVAL;
2033
2034         mutex_lock(&ftrace_lock);
2035         do_for_each_ftrace_rec(pg, rec) {
2036
2037                 if (rec->flags & FTRACE_FL_FAILED)
2038                         continue;
2039
2040                 if (!ftrace_match_record(rec, search, len, type))
2041                         continue;
2042
2043                 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2044                 if (!entry) {
2045                         /* If we did not process any, then return error */
2046                         if (!count)
2047                                 count = -ENOMEM;
2048                         goto out_unlock;
2049                 }
2050
2051                 count++;
2052
2053                 entry->data = data;
2054
2055                 /*
2056                  * The caller might want to do something special
2057                  * for each function we find. We call the callback
2058                  * to give the caller an opportunity to do so.
2059                  */
2060                 if (ops->callback) {
2061                         if (ops->callback(rec->ip, &entry->data) < 0) {
2062                                 /* caller does not like this func */
2063                                 kfree(entry);
2064                                 continue;
2065                         }
2066                 }
2067
2068                 entry->ops = ops;
2069                 entry->ip = rec->ip;
2070
2071                 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2072                 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2073
2074         } while_for_each_ftrace_rec();
2075         __enable_ftrace_function_probe();
2076
2077  out_unlock:
2078         mutex_unlock(&ftrace_lock);
2079
2080         return count;
2081 }
2082
2083 enum {
2084         PROBE_TEST_FUNC         = 1,
2085         PROBE_TEST_DATA         = 2
2086 };
2087
2088 static void
2089 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2090                                   void *data, int flags)
2091 {
2092         struct ftrace_func_probe *entry;
2093         struct hlist_node *n, *tmp;
2094         char str[KSYM_SYMBOL_LEN];
2095         int type = MATCH_FULL;
2096         int i, len = 0;
2097         char *search;
2098
2099         if (glob && (strcmp(glob, "*") || !strlen(glob)))
2100                 glob = NULL;
2101         else {
2102                 int not;
2103
2104                 type = ftrace_setup_glob(glob, strlen(glob), &search, &not);
2105                 len = strlen(search);
2106
2107                 /* we do not support '!' for function probes */
2108                 if (WARN_ON(not))
2109                         return;
2110         }
2111
2112         mutex_lock(&ftrace_lock);
2113         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2114                 struct hlist_head *hhd = &ftrace_func_hash[i];
2115
2116                 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
2117
2118                         /* break up if statements for readability */
2119                         if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2120                                 continue;
2121
2122                         if ((flags & PROBE_TEST_DATA) && entry->data != data)
2123                                 continue;
2124
2125                         /* do this last, since it is the most expensive */
2126                         if (glob) {
2127                                 kallsyms_lookup(entry->ip, NULL, NULL,
2128                                                 NULL, str);
2129                                 if (!ftrace_match(str, glob, len, type))
2130                                         continue;
2131                         }
2132
2133                         hlist_del(&entry->node);
2134                         call_rcu(&entry->rcu, ftrace_free_entry_rcu);
2135                 }
2136         }
2137         __disable_ftrace_function_probe();
2138         mutex_unlock(&ftrace_lock);
2139 }
2140
2141 void
2142 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2143                                 void *data)
2144 {
2145         __unregister_ftrace_function_probe(glob, ops, data,
2146                                           PROBE_TEST_FUNC | PROBE_TEST_DATA);
2147 }
2148
2149 void
2150 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
2151 {
2152         __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
2153 }
2154
2155 void unregister_ftrace_function_probe_all(char *glob)
2156 {
2157         __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
2158 }
2159
2160 static LIST_HEAD(ftrace_commands);
2161 static DEFINE_MUTEX(ftrace_cmd_mutex);
2162
2163 int register_ftrace_command(struct ftrace_func_command *cmd)
2164 {
2165         struct ftrace_func_command *p;
2166         int ret = 0;
2167
2168         mutex_lock(&ftrace_cmd_mutex);
2169         list_for_each_entry(p, &ftrace_commands, list) {
2170                 if (strcmp(cmd->name, p->name) == 0) {
2171                         ret = -EBUSY;
2172                         goto out_unlock;
2173                 }
2174         }
2175         list_add(&cmd->list, &ftrace_commands);
2176  out_unlock:
2177         mutex_unlock(&ftrace_cmd_mutex);
2178
2179         return ret;
2180 }
2181
2182 int unregister_ftrace_command(struct ftrace_func_command *cmd)
2183 {
2184         struct ftrace_func_command *p, *n;
2185         int ret = -ENODEV;
2186
2187         mutex_lock(&ftrace_cmd_mutex);
2188         list_for_each_entry_safe(p, n, &ftrace_commands, list) {
2189                 if (strcmp(cmd->name, p->name) == 0) {
2190                         ret = 0;
2191                         list_del_init(&p->list);
2192                         goto out_unlock;
2193                 }
2194         }
2195  out_unlock:
2196         mutex_unlock(&ftrace_cmd_mutex);
2197
2198         return ret;
2199 }
2200
2201 static int ftrace_process_regex(char *buff, int len, int enable)
2202 {
2203         char *func, *command, *next = buff;
2204         struct ftrace_func_command *p;
2205         int ret = -EINVAL;
2206
2207         func = strsep(&next, ":");
2208
2209         if (!next) {
2210                 ftrace_match_records(func, len, enable);
2211                 return 0;
2212         }
2213
2214         /* command found */
2215
2216         command = strsep(&next, ":");
2217
2218         mutex_lock(&ftrace_cmd_mutex);
2219         list_for_each_entry(p, &ftrace_commands, list) {
2220                 if (strcmp(p->name, command) == 0) {
2221                         ret = p->func(func, command, next, enable);
2222                         goto out_unlock;
2223                 }
2224         }
2225  out_unlock:
2226         mutex_unlock(&ftrace_cmd_mutex);
2227
2228         return ret;
2229 }
2230
2231 static ssize_t
2232 ftrace_regex_write(struct file *file, const char __user *ubuf,
2233                    size_t cnt, loff_t *ppos, int enable)
2234 {
2235         struct ftrace_iterator *iter;
2236         char ch;
2237         size_t read = 0;
2238         ssize_t ret;
2239
2240         if (!cnt || cnt < 0)
2241                 return 0;
2242
2243         mutex_lock(&ftrace_regex_lock);
2244
2245         if (file->f_mode & FMODE_READ) {
2246                 struct seq_file *m = file->private_data;
2247                 iter = m->private;
2248         } else
2249                 iter = file->private_data;
2250
2251         if (!*ppos) {
2252                 iter->flags &= ~FTRACE_ITER_CONT;
2253                 iter->buffer_idx = 0;
2254         }
2255
2256         ret = get_user(ch, ubuf++);
2257         if (ret)
2258                 goto out;
2259         read++;
2260         cnt--;
2261
2262         if (!(iter->flags & ~FTRACE_ITER_CONT)) {
2263                 /* skip white space */
2264                 while (cnt && isspace(ch)) {
2265                         ret = get_user(ch, ubuf++);
2266                         if (ret)
2267                                 goto out;
2268                         read++;
2269                         cnt--;
2270                 }
2271
2272                 if (isspace(ch)) {
2273                         file->f_pos += read;
2274                         ret = read;
2275                         goto out;
2276                 }
2277
2278                 iter->buffer_idx = 0;
2279         }
2280
2281         while (cnt && !isspace(ch)) {
2282                 if (iter->buffer_idx < FTRACE_BUFF_MAX)
2283                         iter->buffer[iter->buffer_idx++] = ch;
2284                 else {
2285                         ret = -EINVAL;
2286                         goto out;
2287                 }
2288                 ret = get_user(ch, ubuf++);
2289                 if (ret)
2290                         goto out;
2291                 read++;
2292                 cnt--;
2293         }
2294
2295         if (isspace(ch)) {
2296                 iter->filtered++;
2297                 iter->buffer[iter->buffer_idx] = 0;
2298                 ret = ftrace_process_regex(iter->buffer,
2299                                            iter->buffer_idx, enable);
2300                 if (ret)
2301                         goto out;
2302                 iter->buffer_idx = 0;
2303         } else
2304                 iter->flags |= FTRACE_ITER_CONT;
2305
2306
2307         file->f_pos += read;
2308
2309         ret = read;
2310  out:
2311         mutex_unlock(&ftrace_regex_lock);
2312
2313         return ret;
2314 }
2315
2316 static ssize_t
2317 ftrace_filter_write(struct file *file, const char __user *ubuf,
2318                     size_t cnt, loff_t *ppos)
2319 {
2320         return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
2321 }
2322
2323 static ssize_t
2324 ftrace_notrace_write(struct file *file, const char __user *ubuf,
2325                      size_t cnt, loff_t *ppos)
2326 {
2327         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
2328 }
2329
2330 static void
2331 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
2332 {
2333         if (unlikely(ftrace_disabled))
2334                 return;
2335
2336         mutex_lock(&ftrace_regex_lock);
2337         if (reset)
2338                 ftrace_filter_reset(enable);
2339         if (buf)
2340                 ftrace_match_records(buf, len, enable);
2341         mutex_unlock(&ftrace_regex_lock);
2342 }
2343
2344 /**
2345  * ftrace_set_filter - set a function to filter on in ftrace
2346  * @buf - the string that holds the function filter text.
2347  * @len - the length of the string.
2348  * @reset - non zero to reset all filters before applying this filter.
2349  *
2350  * Filters denote which functions should be enabled when tracing is enabled.
2351  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2352  */
2353 void ftrace_set_filter(unsigned char *buf, int len, int reset)
2354 {
2355         ftrace_set_regex(buf, len, reset, 1);
2356 }
2357
2358 /**
2359  * ftrace_set_notrace - set a function to not trace in ftrace
2360  * @buf - the string that holds the function notrace text.
2361  * @len - the length of the string.
2362  * @reset - non zero to reset all filters before applying this filter.
2363  *
2364  * Notrace Filters denote which functions should not be enabled when tracing
2365  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2366  * for tracing.
2367  */
2368 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
2369 {
2370         ftrace_set_regex(buf, len, reset, 0);
2371 }
2372
2373 /*
2374  * command line interface to allow users to set filters on boot up.
2375  */
2376 #define FTRACE_FILTER_SIZE              COMMAND_LINE_SIZE
2377 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
2378 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
2379
2380 static int __init set_ftrace_notrace(char *str)
2381 {
2382         strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
2383         return 1;
2384 }
2385 __setup("ftrace_notrace=", set_ftrace_notrace);
2386
2387 static int __init set_ftrace_filter(char *str)
2388 {
2389         strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
2390         return 1;
2391 }
2392 __setup("ftrace_filter=", set_ftrace_filter);
2393
2394 static void __init set_ftrace_early_filter(char *buf, int enable)
2395 {
2396         char *func;
2397
2398         while (buf) {
2399                 func = strsep(&buf, ",");
2400                 ftrace_set_regex(func, strlen(func), 0, enable);
2401         }
2402 }
2403
2404 static void __init set_ftrace_early_filters(void)
2405 {
2406         if (ftrace_filter_buf[0])
2407                 set_ftrace_early_filter(ftrace_filter_buf, 1);
2408         if (ftrace_notrace_buf[0])
2409                 set_ftrace_early_filter(ftrace_notrace_buf, 0);
2410 }
2411
2412 static int
2413 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
2414 {
2415         struct seq_file *m = (struct seq_file *)file->private_data;
2416         struct ftrace_iterator *iter;
2417
2418         mutex_lock(&ftrace_regex_lock);
2419         if (file->f_mode & FMODE_READ) {
2420                 iter = m->private;
2421
2422                 seq_release(inode, file);
2423         } else
2424                 iter = file->private_data;
2425
2426         if (iter->buffer_idx) {
2427                 iter->filtered++;
2428                 iter->buffer[iter->buffer_idx] = 0;
2429                 ftrace_match_records(iter->buffer, iter->buffer_idx, enable);
2430         }
2431
2432         mutex_lock(&ftrace_lock);
2433         if (ftrace_start_up && ftrace_enabled)
2434                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
2435         mutex_unlock(&ftrace_lock);
2436
2437         kfree(iter);
2438         mutex_unlock(&ftrace_regex_lock);
2439         return 0;
2440 }
2441
2442 static int
2443 ftrace_filter_release(struct inode *inode, struct file *file)
2444 {
2445         return ftrace_regex_release(inode, file, 1);
2446 }
2447
2448 static int
2449 ftrace_notrace_release(struct inode *inode, struct file *file)
2450 {
2451         return ftrace_regex_release(inode, file, 0);
2452 }
2453
2454 static const struct file_operations ftrace_avail_fops = {
2455         .open = ftrace_avail_open,
2456         .read = seq_read,
2457         .llseek = seq_lseek,
2458         .release = ftrace_avail_release,
2459 };
2460
2461 static const struct file_operations ftrace_failures_fops = {
2462         .open = ftrace_failures_open,
2463         .read = seq_read,
2464         .llseek = seq_lseek,
2465         .release = ftrace_avail_release,
2466 };
2467
2468 static const struct file_operations ftrace_filter_fops = {
2469         .open = ftrace_filter_open,
2470         .read = seq_read,
2471         .write = ftrace_filter_write,
2472         .llseek = ftrace_regex_lseek,
2473         .release = ftrace_filter_release,
2474 };
2475
2476 static const struct file_operations ftrace_notrace_fops = {
2477         .open = ftrace_notrace_open,
2478         .read = seq_read,
2479         .write = ftrace_notrace_write,
2480         .llseek = ftrace_regex_lseek,
2481         .release = ftrace_notrace_release,
2482 };
2483
2484 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2485
2486 static DEFINE_MUTEX(graph_lock);
2487
2488 int ftrace_graph_count;
2489 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
2490
2491 static void *
2492 g_next(struct seq_file *m, void *v, loff_t *pos)
2493 {
2494         unsigned long *array = m->private;
2495         int index = *pos;
2496
2497         (*pos)++;
2498
2499         if (index >= ftrace_graph_count)
2500                 return NULL;
2501
2502         return &array[index];
2503 }
2504
2505 static void *g_start(struct seq_file *m, loff_t *pos)
2506 {
2507         void *p = NULL;
2508
2509         mutex_lock(&graph_lock);
2510
2511         /* Nothing, tell g_show to print all functions are enabled */
2512         if (!ftrace_graph_count && !*pos)
2513                 return (void *)1;
2514
2515         p = g_next(m, p, pos);
2516
2517         return p;
2518 }
2519
2520 static void g_stop(struct seq_file *m, void *p)
2521 {
2522         mutex_unlock(&graph_lock);
2523 }
2524
2525 static int g_show(struct seq_file *m, void *v)
2526 {
2527         unsigned long *ptr = v;
2528         char str[KSYM_SYMBOL_LEN];
2529
2530         if (!ptr)
2531                 return 0;
2532
2533         if (ptr == (unsigned long *)1) {
2534                 seq_printf(m, "#### all functions enabled ####\n");
2535                 return 0;
2536         }
2537
2538         kallsyms_lookup(*ptr, NULL, NULL, NULL, str);
2539
2540         seq_printf(m, "%s\n", str);
2541
2542         return 0;
2543 }
2544
2545 static struct seq_operations ftrace_graph_seq_ops = {
2546         .start = g_start,
2547         .next = g_next,
2548         .stop = g_stop,
2549         .show = g_show,
2550 };
2551
2552 static int
2553 ftrace_graph_open(struct inode *inode, struct file *file)
2554 {
2555         int ret = 0;
2556
2557         if (unlikely(ftrace_disabled))
2558                 return -ENODEV;
2559
2560         mutex_lock(&graph_lock);
2561         if ((file->f_mode & FMODE_WRITE) &&
2562             !(file->f_flags & O_APPEND)) {
2563                 ftrace_graph_count = 0;
2564                 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
2565         }
2566
2567         if (file->f_mode & FMODE_READ) {
2568                 ret = seq_open(file, &ftrace_graph_seq_ops);
2569                 if (!ret) {
2570                         struct seq_file *m = file->private_data;
2571                         m->private = ftrace_graph_funcs;
2572                 }
2573         } else
2574                 file->private_data = ftrace_graph_funcs;
2575         mutex_unlock(&graph_lock);
2576
2577         return ret;
2578 }
2579
2580 static int
2581 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
2582 {
2583         struct dyn_ftrace *rec;
2584         struct ftrace_page *pg;
2585         int search_len;
2586         int found = 0;
2587         int type, not;
2588         char *search;
2589         bool exists;
2590         int i;
2591
2592         if (ftrace_disabled)
2593                 return -ENODEV;
2594
2595         /* decode regex */
2596         type = ftrace_setup_glob(buffer, strlen(buffer), &search, &not);
2597         if (not)
2598                 return -EINVAL;
2599
2600         search_len = strlen(search);
2601
2602         mutex_lock(&ftrace_lock);
2603         do_for_each_ftrace_rec(pg, rec) {
2604
2605                 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
2606                         break;
2607
2608                 if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
2609                         continue;
2610
2611                 if (ftrace_match_record(rec, search, search_len, type)) {
2612                         /* ensure it is not already in the array */
2613                         exists = false;
2614                         for (i = 0; i < *idx; i++)
2615                                 if (array[i] == rec->ip) {
2616                                         exists = true;
2617                                         break;
2618                                 }
2619                         if (!exists) {
2620                                 array[(*idx)++] = rec->ip;
2621                                 found = 1;
2622                         }
2623                 }
2624         } while_for_each_ftrace_rec();
2625
2626         mutex_unlock(&ftrace_lock);
2627
2628         return found ? 0 : -EINVAL;
2629 }
2630
2631 static ssize_t
2632 ftrace_graph_write(struct file *file, const char __user *ubuf,
2633                    size_t cnt, loff_t *ppos)
2634 {
2635         unsigned char buffer[FTRACE_BUFF_MAX+1];
2636         unsigned long *array;
2637         size_t read = 0;
2638         ssize_t ret;
2639         int index = 0;
2640         char ch;
2641
2642         if (!cnt || cnt < 0)
2643                 return 0;
2644
2645         mutex_lock(&graph_lock);
2646
2647         if (ftrace_graph_count >= FTRACE_GRAPH_MAX_FUNCS) {
2648                 ret = -EBUSY;
2649                 goto out;
2650         }
2651
2652         if (file->f_mode & FMODE_READ) {
2653                 struct seq_file *m = file->private_data;
2654                 array = m->private;
2655         } else
2656                 array = file->private_data;
2657
2658         ret = get_user(ch, ubuf++);
2659         if (ret)
2660                 goto out;
2661         read++;
2662         cnt--;
2663
2664         /* skip white space */
2665         while (cnt && isspace(ch)) {
2666                 ret = get_user(ch, ubuf++);
2667                 if (ret)
2668                         goto out;
2669                 read++;
2670                 cnt--;
2671         }
2672
2673         if (isspace(ch)) {
2674                 *ppos += read;
2675                 ret = read;
2676                 goto out;
2677         }
2678
2679         while (cnt && !isspace(ch)) {
2680                 if (index < FTRACE_BUFF_MAX)
2681                         buffer[index++] = ch;
2682                 else {
2683                         ret = -EINVAL;
2684                         goto out;
2685                 }
2686                 ret = get_user(ch, ubuf++);
2687                 if (ret)
2688                         goto out;
2689                 read++;
2690                 cnt--;
2691         }
2692         buffer[index] = 0;
2693
2694         /* we allow only one expression at a time */
2695         ret = ftrace_set_func(array, &ftrace_graph_count, buffer);
2696         if (ret)
2697                 goto out;
2698
2699         file->f_pos += read;
2700
2701         ret = read;
2702  out:
2703         mutex_unlock(&graph_lock);
2704
2705         return ret;
2706 }
2707
2708 static const struct file_operations ftrace_graph_fops = {
2709         .open = ftrace_graph_open,
2710         .read = seq_read,
2711         .write = ftrace_graph_write,
2712 };
2713 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2714
2715 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
2716 {
2717
2718         trace_create_file("available_filter_functions", 0444,
2719                         d_tracer, NULL, &ftrace_avail_fops);
2720
2721         trace_create_file("failures", 0444,
2722                         d_tracer, NULL, &ftrace_failures_fops);
2723
2724         trace_create_file("set_ftrace_filter", 0644, d_tracer,
2725                         NULL, &ftrace_filter_fops);
2726
2727         trace_create_file("set_ftrace_notrace", 0644, d_tracer,
2728                                     NULL, &ftrace_notrace_fops);
2729
2730 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2731         trace_create_file("set_graph_function", 0444, d_tracer,
2732                                     NULL,
2733                                     &ftrace_graph_fops);
2734 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2735
2736         return 0;
2737 }
2738
2739 static int ftrace_convert_nops(struct module *mod,
2740                                unsigned long *start,
2741                                unsigned long *end)
2742 {
2743         unsigned long *p;
2744         unsigned long addr;
2745         unsigned long flags;
2746
2747         mutex_lock(&ftrace_lock);
2748         p = start;
2749         while (p < end) {
2750                 addr = ftrace_call_adjust(*p++);
2751                 /*
2752                  * Some architecture linkers will pad between
2753                  * the different mcount_loc sections of different
2754                  * object files to satisfy alignments.
2755                  * Skip any NULL pointers.
2756                  */
2757                 if (!addr)
2758                         continue;
2759                 ftrace_record_ip(addr);
2760         }
2761
2762         /* disable interrupts to prevent kstop machine */
2763         local_irq_save(flags);
2764         ftrace_update_code(mod);
2765         local_irq_restore(flags);
2766         mutex_unlock(&ftrace_lock);
2767
2768         return 0;
2769 }
2770
2771 #ifdef CONFIG_MODULES
2772 void ftrace_release(void *start, void *end)
2773 {
2774         struct dyn_ftrace *rec;
2775         struct ftrace_page *pg;
2776         unsigned long s = (unsigned long)start;
2777         unsigned long e = (unsigned long)end;
2778
2779         if (ftrace_disabled || !start || start == end)
2780                 return;
2781
2782         mutex_lock(&ftrace_lock);
2783         do_for_each_ftrace_rec(pg, rec) {
2784                 if ((rec->ip >= s) && (rec->ip < e)) {
2785                         /*
2786                          * rec->ip is changed in ftrace_free_rec()
2787                          * It should not between s and e if record was freed.
2788                          */
2789                         FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
2790                         ftrace_free_rec(rec);
2791                 }
2792         } while_for_each_ftrace_rec();
2793         mutex_unlock(&ftrace_lock);
2794 }
2795
2796 static void ftrace_init_module(struct module *mod,
2797                                unsigned long *start, unsigned long *end)
2798 {
2799         if (ftrace_disabled || start == end)
2800                 return;
2801         ftrace_convert_nops(mod, start, end);
2802 }
2803
2804 static int ftrace_module_notify(struct notifier_block *self,
2805                                 unsigned long val, void *data)
2806 {
2807         struct module *mod = data;
2808
2809         switch (val) {
2810         case MODULE_STATE_COMING:
2811                 ftrace_init_module(mod, mod->ftrace_callsites,
2812                                    mod->ftrace_callsites +
2813                                    mod->num_ftrace_callsites);
2814                 break;
2815         case MODULE_STATE_GOING:
2816                 ftrace_release(mod->ftrace_callsites,
2817                                mod->ftrace_callsites +
2818                                mod->num_ftrace_callsites);
2819                 break;
2820         }
2821
2822         return 0;
2823 }
2824 #else
2825 static int ftrace_module_notify(struct notifier_block *self,
2826                                 unsigned long val, void *data)
2827 {
2828         return 0;
2829 }
2830 #endif /* CONFIG_MODULES */
2831
2832 struct notifier_block ftrace_module_nb = {
2833         .notifier_call = ftrace_module_notify,
2834         .priority = 0,
2835 };
2836
2837 extern unsigned long __start_mcount_loc[];
2838 extern unsigned long __stop_mcount_loc[];
2839
2840 void __init ftrace_init(void)
2841 {
2842         unsigned long count, addr, flags;
2843         int ret;
2844
2845         /* Keep the ftrace pointer to the stub */
2846         addr = (unsigned long)ftrace_stub;
2847
2848         local_irq_save(flags);
2849         ftrace_dyn_arch_init(&addr);
2850         local_irq_restore(flags);
2851
2852         /* ftrace_dyn_arch_init places the return code in addr */
2853         if (addr)
2854                 goto failed;
2855
2856         count = __stop_mcount_loc - __start_mcount_loc;
2857
2858         ret = ftrace_dyn_table_alloc(count);
2859         if (ret)
2860                 goto failed;
2861
2862         last_ftrace_enabled = ftrace_enabled = 1;
2863
2864         ret = ftrace_convert_nops(NULL,
2865                                   __start_mcount_loc,
2866                                   __stop_mcount_loc);
2867
2868         ret = register_module_notifier(&ftrace_module_nb);
2869         if (ret)
2870                 pr_warning("Failed to register trace ftrace module notifier\n");
2871
2872         set_ftrace_early_filters();
2873
2874         return;
2875  failed:
2876         ftrace_disabled = 1;
2877 }
2878
2879 #else
2880
2881 static int __init ftrace_nodyn_init(void)
2882 {
2883         ftrace_enabled = 1;
2884         return 0;
2885 }
2886 device_initcall(ftrace_nodyn_init);
2887
2888 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
2889 static inline void ftrace_startup_enable(int command) { }
2890 /* Keep as macros so we do not need to define the commands */
2891 # define ftrace_startup(command)        do { } while (0)
2892 # define ftrace_shutdown(command)       do { } while (0)
2893 # define ftrace_startup_sysctl()        do { } while (0)
2894 # define ftrace_shutdown_sysctl()       do { } while (0)
2895 #endif /* CONFIG_DYNAMIC_FTRACE */
2896
2897 static ssize_t
2898 ftrace_pid_read(struct file *file, char __user *ubuf,
2899                        size_t cnt, loff_t *ppos)
2900 {
2901         char buf[64];
2902         int r;
2903
2904         if (ftrace_pid_trace == ftrace_swapper_pid)
2905                 r = sprintf(buf, "swapper tasks\n");
2906         else if (ftrace_pid_trace)
2907                 r = sprintf(buf, "%u\n", pid_vnr(ftrace_pid_trace));
2908         else
2909                 r = sprintf(buf, "no pid\n");
2910
2911         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2912 }
2913
2914 static void clear_ftrace_swapper(void)
2915 {
2916         struct task_struct *p;
2917         int cpu;
2918
2919         get_online_cpus();
2920         for_each_online_cpu(cpu) {
2921                 p = idle_task(cpu);
2922                 clear_tsk_trace_trace(p);
2923         }
2924         put_online_cpus();
2925 }
2926
2927 static void set_ftrace_swapper(void)
2928 {
2929         struct task_struct *p;
2930         int cpu;
2931
2932         get_online_cpus();
2933         for_each_online_cpu(cpu) {
2934                 p = idle_task(cpu);
2935                 set_tsk_trace_trace(p);
2936         }
2937         put_online_cpus();
2938 }
2939
2940 static void clear_ftrace_pid(struct pid *pid)
2941 {
2942         struct task_struct *p;
2943
2944         rcu_read_lock();
2945         do_each_pid_task(pid, PIDTYPE_PID, p) {
2946                 clear_tsk_trace_trace(p);
2947         } while_each_pid_task(pid, PIDTYPE_PID, p);
2948         rcu_read_unlock();
2949
2950         put_pid(pid);
2951 }
2952
2953 static void set_ftrace_pid(struct pid *pid)
2954 {
2955         struct task_struct *p;
2956
2957         rcu_read_lock();
2958         do_each_pid_task(pid, PIDTYPE_PID, p) {
2959                 set_tsk_trace_trace(p);
2960         } while_each_pid_task(pid, PIDTYPE_PID, p);
2961         rcu_read_unlock();
2962 }
2963
2964 static void clear_ftrace_pid_task(struct pid **pid)
2965 {
2966         if (*pid == ftrace_swapper_pid)
2967                 clear_ftrace_swapper();
2968         else
2969                 clear_ftrace_pid(*pid);
2970
2971         *pid = NULL;
2972 }
2973
2974 static void set_ftrace_pid_task(struct pid *pid)
2975 {
2976         if (pid == ftrace_swapper_pid)
2977                 set_ftrace_swapper();
2978         else
2979                 set_ftrace_pid(pid);
2980 }
2981
2982 static ssize_t
2983 ftrace_pid_write(struct file *filp, const char __user *ubuf,
2984                    size_t cnt, loff_t *ppos)
2985 {
2986         struct pid *pid;
2987         char buf[64];
2988         long val;
2989         int ret;
2990
2991         if (cnt >= sizeof(buf))
2992                 return -EINVAL;
2993
2994         if (copy_from_user(&buf, ubuf, cnt))
2995                 return -EFAULT;
2996
2997         buf[cnt] = 0;
2998
2999         ret = strict_strtol(buf, 10, &val);
3000         if (ret < 0)
3001                 return ret;
3002
3003         mutex_lock(&ftrace_lock);
3004         if (val < 0) {
3005                 /* disable pid tracing */
3006                 if (!ftrace_pid_trace)
3007                         goto out;
3008
3009                 clear_ftrace_pid_task(&ftrace_pid_trace);
3010
3011         } else {
3012                 /* swapper task is special */
3013                 if (!val) {
3014                         pid = ftrace_swapper_pid;
3015                         if (pid == ftrace_pid_trace)
3016                                 goto out;
3017                 } else {
3018                         pid = find_get_pid(val);
3019
3020                         if (pid == ftrace_pid_trace) {
3021                                 put_pid(pid);
3022                                 goto out;
3023                         }
3024                 }
3025
3026                 if (ftrace_pid_trace)
3027                         clear_ftrace_pid_task(&ftrace_pid_trace);
3028
3029                 if (!pid)
3030                         goto out;
3031
3032                 ftrace_pid_trace = pid;
3033
3034                 set_ftrace_pid_task(ftrace_pid_trace);
3035         }
3036
3037         /* update the function call */
3038         ftrace_update_pid_func();
3039         ftrace_startup_enable(0);
3040
3041  out:
3042         mutex_unlock(&ftrace_lock);
3043
3044         return cnt;
3045 }
3046
3047 static const struct file_operations ftrace_pid_fops = {
3048         .read = ftrace_pid_read,
3049         .write = ftrace_pid_write,
3050 };
3051
3052 static __init int ftrace_init_debugfs(void)
3053 {
3054         struct dentry *d_tracer;
3055
3056         d_tracer = tracing_init_dentry();
3057         if (!d_tracer)
3058                 return 0;
3059
3060         ftrace_init_dyn_debugfs(d_tracer);
3061
3062         trace_create_file("set_ftrace_pid", 0644, d_tracer,
3063                             NULL, &ftrace_pid_fops);
3064
3065         ftrace_profile_debugfs(d_tracer);
3066
3067         return 0;
3068 }
3069 fs_initcall(ftrace_init_debugfs);
3070
3071 /**
3072  * ftrace_kill - kill ftrace
3073  *
3074  * This function should be used by panic code. It stops ftrace
3075  * but in a not so nice way. If you need to simply kill ftrace
3076  * from a non-atomic section, use ftrace_kill.
3077  */
3078 void ftrace_kill(void)
3079 {
3080         ftrace_disabled = 1;
3081         ftrace_enabled = 0;
3082         clear_ftrace_function();
3083 }
3084
3085 /**
3086  * register_ftrace_function - register a function for profiling
3087  * @ops - ops structure that holds the function for profiling.
3088  *
3089  * Register a function to be called by all functions in the
3090  * kernel.
3091  *
3092  * Note: @ops->func and all the functions it calls must be labeled
3093  *       with "notrace", otherwise it will go into a
3094  *       recursive loop.
3095  */
3096 int register_ftrace_function(struct ftrace_ops *ops)
3097 {
3098         int ret;
3099
3100         if (unlikely(ftrace_disabled))
3101                 return -1;
3102
3103         mutex_lock(&ftrace_lock);
3104
3105         ret = __register_ftrace_function(ops);
3106         ftrace_startup(0);
3107
3108         mutex_unlock(&ftrace_lock);
3109         return ret;
3110 }
3111
3112 /**
3113  * unregister_ftrace_function - unregister a function for profiling.
3114  * @ops - ops structure that holds the function to unregister
3115  *
3116  * Unregister a function that was added to be called by ftrace profiling.
3117  */
3118 int unregister_ftrace_function(struct ftrace_ops *ops)
3119 {
3120         int ret;
3121
3122         mutex_lock(&ftrace_lock);
3123         ret = __unregister_ftrace_function(ops);
3124         ftrace_shutdown(0);
3125         mutex_unlock(&ftrace_lock);
3126
3127         return ret;
3128 }
3129
3130 int
3131 ftrace_enable_sysctl(struct ctl_table *table, int write,
3132                      struct file *file, void __user *buffer, size_t *lenp,
3133                      loff_t *ppos)
3134 {
3135         int ret;
3136
3137         if (unlikely(ftrace_disabled))
3138                 return -ENODEV;
3139
3140         mutex_lock(&ftrace_lock);
3141
3142         ret  = proc_dointvec(table, write, file, buffer, lenp, ppos);
3143
3144         if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
3145                 goto out;
3146
3147         last_ftrace_enabled = ftrace_enabled;
3148
3149         if (ftrace_enabled) {
3150
3151                 ftrace_startup_sysctl();
3152
3153                 /* we are starting ftrace again */
3154                 if (ftrace_list != &ftrace_list_end) {
3155                         if (ftrace_list->next == &ftrace_list_end)
3156                                 ftrace_trace_function = ftrace_list->func;
3157                         else
3158                                 ftrace_trace_function = ftrace_list_func;
3159                 }
3160
3161         } else {
3162                 /* stopping ftrace calls (just send to ftrace_stub) */
3163                 ftrace_trace_function = ftrace_stub;
3164
3165                 ftrace_shutdown_sysctl();
3166         }
3167
3168  out:
3169         mutex_unlock(&ftrace_lock);
3170         return ret;
3171 }
3172
3173 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3174
3175 static int ftrace_graph_active;
3176 static struct notifier_block ftrace_suspend_notifier;
3177
3178 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
3179 {
3180         return 0;
3181 }
3182
3183 /* The callbacks that hook a function */
3184 trace_func_graph_ret_t ftrace_graph_return =
3185                         (trace_func_graph_ret_t)ftrace_stub;
3186 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
3187
3188 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3189 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
3190 {
3191         int i;
3192         int ret = 0;
3193         unsigned long flags;
3194         int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
3195         struct task_struct *g, *t;
3196
3197         for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
3198                 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
3199                                         * sizeof(struct ftrace_ret_stack),
3200                                         GFP_KERNEL);
3201                 if (!ret_stack_list[i]) {
3202                         start = 0;
3203                         end = i;
3204                         ret = -ENOMEM;
3205                         goto free;
3206                 }
3207         }
3208
3209         read_lock_irqsave(&tasklist_lock, flags);
3210         do_each_thread(g, t) {
3211                 if (start == end) {
3212                         ret = -EAGAIN;
3213                         goto unlock;
3214                 }
3215
3216                 if (t->ret_stack == NULL) {
3217                         t->curr_ret_stack = -1;
3218                         /* Make sure IRQs see the -1 first: */
3219                         barrier();
3220                         t->ret_stack = ret_stack_list[start++];
3221                         atomic_set(&t->tracing_graph_pause, 0);
3222                         atomic_set(&t->trace_overrun, 0);
3223                 }
3224         } while_each_thread(g, t);
3225
3226 unlock:
3227         read_unlock_irqrestore(&tasklist_lock, flags);
3228 free:
3229         for (i = start; i < end; i++)
3230                 kfree(ret_stack_list[i]);
3231         return ret;
3232 }
3233
3234 static void
3235 ftrace_graph_probe_sched_switch(struct rq *__rq, struct task_struct *prev,
3236                                 struct task_struct *next)
3237 {
3238         unsigned long long timestamp;
3239         int index;
3240
3241         /*
3242          * Does the user want to count the time a function was asleep.
3243          * If so, do not update the time stamps.
3244          */
3245         if (trace_flags & TRACE_ITER_SLEEP_TIME)
3246                 return;
3247
3248         timestamp = trace_clock_local();
3249
3250         prev->ftrace_timestamp = timestamp;
3251
3252         /* only process tasks that we timestamped */
3253         if (!next->ftrace_timestamp)
3254                 return;
3255
3256         /*
3257          * Update all the counters in next to make up for the
3258          * time next was sleeping.
3259          */
3260         timestamp -= next->ftrace_timestamp;
3261
3262         for (index = next->curr_ret_stack; index >= 0; index--)
3263                 next->ret_stack[index].calltime += timestamp;
3264 }
3265
3266 /* Allocate a return stack for each task */
3267 static int start_graph_tracing(void)
3268 {
3269         struct ftrace_ret_stack **ret_stack_list;
3270         int ret, cpu;
3271
3272         ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
3273                                 sizeof(struct ftrace_ret_stack *),
3274                                 GFP_KERNEL);
3275
3276         if (!ret_stack_list)
3277                 return -ENOMEM;
3278
3279         /* The cpu_boot init_task->ret_stack will never be freed */
3280         for_each_online_cpu(cpu)
3281                 ftrace_graph_init_task(idle_task(cpu));
3282
3283         do {
3284                 ret = alloc_retstack_tasklist(ret_stack_list);
3285         } while (ret == -EAGAIN);
3286
3287         if (!ret) {
3288                 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch);
3289                 if (ret)
3290                         pr_info("ftrace_graph: Couldn't activate tracepoint"
3291                                 " probe to kernel_sched_switch\n");
3292         }
3293
3294         kfree(ret_stack_list);
3295         return ret;
3296 }
3297
3298 /*
3299  * Hibernation protection.
3300  * The state of the current task is too much unstable during
3301  * suspend/restore to disk. We want to protect against that.
3302  */
3303 static int
3304 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
3305                                                         void *unused)
3306 {
3307         switch (state) {
3308         case PM_HIBERNATION_PREPARE:
3309                 pause_graph_tracing();
3310                 break;
3311
3312         case PM_POST_HIBERNATION:
3313                 unpause_graph_tracing();
3314                 break;
3315         }
3316         return NOTIFY_DONE;
3317 }
3318
3319 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
3320                         trace_func_graph_ent_t entryfunc)
3321 {
3322         int ret = 0;
3323
3324         mutex_lock(&ftrace_lock);
3325
3326         /* we currently allow only one tracer registered at a time */
3327         if (ftrace_graph_active) {
3328                 ret = -EBUSY;
3329                 goto out;
3330         }
3331
3332         ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
3333         register_pm_notifier(&ftrace_suspend_notifier);
3334
3335         ftrace_graph_active++;
3336         ret = start_graph_tracing();
3337         if (ret) {
3338                 ftrace_graph_active--;
3339                 goto out;
3340         }
3341
3342         ftrace_graph_return = retfunc;
3343         ftrace_graph_entry = entryfunc;
3344
3345         ftrace_startup(FTRACE_START_FUNC_RET);
3346
3347 out:
3348         mutex_unlock(&ftrace_lock);
3349         return ret;
3350 }
3351
3352 void unregister_ftrace_graph(void)
3353 {
3354         mutex_lock(&ftrace_lock);
3355
3356         if (unlikely(!ftrace_graph_active))
3357                 goto out;
3358
3359         ftrace_graph_active--;
3360         unregister_trace_sched_switch(ftrace_graph_probe_sched_switch);
3361         ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
3362         ftrace_graph_entry = ftrace_graph_entry_stub;
3363         ftrace_shutdown(FTRACE_STOP_FUNC_RET);
3364         unregister_pm_notifier(&ftrace_suspend_notifier);
3365
3366  out:
3367         mutex_unlock(&ftrace_lock);
3368 }
3369
3370 /* Allocate a return stack for newly created task */
3371 void ftrace_graph_init_task(struct task_struct *t)
3372 {
3373         if (ftrace_graph_active) {
3374                 t->ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
3375                                 * sizeof(struct ftrace_ret_stack),
3376                                 GFP_KERNEL);
3377                 if (!t->ret_stack)
3378                         return;
3379                 t->curr_ret_stack = -1;
3380                 atomic_set(&t->tracing_graph_pause, 0);
3381                 atomic_set(&t->trace_overrun, 0);
3382                 t->ftrace_timestamp = 0;
3383         } else
3384                 t->ret_stack = NULL;
3385 }
3386
3387 void ftrace_graph_exit_task(struct task_struct *t)
3388 {
3389         struct ftrace_ret_stack *ret_stack = t->ret_stack;
3390
3391         t->ret_stack = NULL;
3392         /* NULL must become visible to IRQs before we free it: */
3393         barrier();
3394
3395         kfree(ret_stack);
3396 }
3397
3398 void ftrace_graph_stop(void)
3399 {
3400         ftrace_stop();
3401 }
3402 #endif
3403