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 || !ftrace_profile_enabled)
 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 || !ftrace_profile_enabled)
 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                         /*
 728                          * unregister_ftrace_profiler calls stop_machine
 729                          * so this acts like an synchronize_sched.
 730                          */
 731                         unregister_ftrace_profiler();
 732                 }
 733         }
 734  out:
 735         mutex_unlock(&ftrace_profile_lock);
 736
 737         filp->f_pos += cnt;
 738
 739         return cnt;
 740 }
 741
 742 static ssize_t
 743 ftrace_profile_read(struct file *filp, char __user *ubuf,
 744                      size_t cnt, loff_t *ppos)
 745 {
 746         char buf[64];           /* big enough to hold a number */
 747         int r;
 748
 749         r = sprintf(buf, "%u\n", ftrace_profile_enabled);
 750         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 751 }
 752
 753 static const struct file_operations ftrace_profile_fops = {
 754         .open           = tracing_open_generic,
 755         .read           = ftrace_profile_read,
 756         .write          = ftrace_profile_write,
 757 };
 758
 759 /* used to initialize the real stat files */
 760 static struct tracer_stat function_stats __initdata = {
 761         .name           = "functions",
 762         .stat_start     = function_stat_start,
 763         .stat_next      = function_stat_next,
 764         .stat_cmp       = function_stat_cmp,
 765         .stat_headers   = function_stat_headers,
 766         .stat_show      = function_stat_show
 767 };
 768
 769 static void ftrace_profile_debugfs(struct dentry *d_tracer)
 770 {
 771         struct ftrace_profile_stat *stat;
 772         struct dentry *entry;
 773         char *name;
 774         int ret;
 775         int cpu;
 776
 777         for_each_possible_cpu(cpu) {
 778                 stat = &per_cpu(ftrace_profile_stats, cpu);
 779
 780                 /* allocate enough for function name + cpu number */
 781                 name = kmalloc(32, GFP_KERNEL);
 782                 if (!name) {
 783                         /*
 784                          * The files created are permanent, if something happens
 785                          * we still do not free memory.
 786                          */
 787                         kfree(stat);
 788                         WARN(1,
 789                              "Could not allocate stat file for cpu %d\n",
 790                              cpu);
 791                         return;
 792                 }
 793                 stat->stat = function_stats;
 794                 snprintf(name, 32, "function%d", cpu);
 795                 stat->stat.name = name;
 796                 ret = register_stat_tracer(&stat->stat);
 797                 if (ret) {
 798                         WARN(1,
 799                              "Could not register function stat for cpu %d\n",
 800                              cpu);
 801                         kfree(name);
 802                         return;
 803                 }
 804         }
 805
 806         entry = debugfs_create_file("function_profile_enabled", 0644,
 807                                     d_tracer, NULL, &ftrace_profile_fops);
 808         if (!entry)
 809                 pr_warning("Could not create debugfs "
 810                            "'function_profile_enabled' entry\n");
 811 }
 812
 813 #else /* CONFIG_FUNCTION_PROFILER */
 814 static void ftrace_profile_debugfs(struct dentry *d_tracer)
 815 {
 816 }
 817 #endif /* CONFIG_FUNCTION_PROFILER */
 818
 819 /* set when tracing only a pid */
 820 struct pid *ftrace_pid_trace;
 821 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
 822
 823 #ifdef CONFIG_DYNAMIC_FTRACE
 824
 825 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
 826 # error Dynamic ftrace depends on MCOUNT_RECORD
 827 #endif
 828
 829 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
 830
 831 struct ftrace_func_probe {
 832         struct hlist_node       node;
 833         struct ftrace_probe_ops *ops;
 834         unsigned long           flags;
 835         unsigned long           ip;
 836         void                    *data;
 837         struct rcu_head         rcu;
 838 };
 839
 840 enum {
 841         FTRACE_ENABLE_CALLS             = (1 << 0),
 842         FTRACE_DISABLE_CALLS            = (1 << 1),
 843         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 844         FTRACE_ENABLE_MCOUNT            = (1 << 3),
 845         FTRACE_DISABLE_MCOUNT           = (1 << 4),
 846         FTRACE_START_FUNC_RET           = (1 << 5),
 847         FTRACE_STOP_FUNC_RET            = (1 << 6),
 848 };
 849
 850 static int ftrace_filtered;
 851
 852 static struct dyn_ftrace *ftrace_new_addrs;
 853
 854 static DEFINE_MUTEX(ftrace_regex_lock);
 855
 856 struct ftrace_page {
 857         struct ftrace_page      *next;
 858         int                     index;
 859         struct dyn_ftrace       records[];
 860 };
 861
 862 #define ENTRIES_PER_PAGE \
 863   ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
 864
 865 /* estimate from running different kernels */
 866 #define NR_TO_INIT              10000
 867
 868 static struct ftrace_page       *ftrace_pages_start;
 869 static struct ftrace_page       *ftrace_pages;
 870
 871 static struct dyn_ftrace *ftrace_free_records;
 872
 873 /*
 874  * This is a double for. Do not use 'break' to break out of the loop,
 875  * you must use a goto.
 876  */
 877 #define do_for_each_ftrace_rec(pg, rec)                                 \
 878         for (pg = ftrace_pages_start; pg; pg = pg->next) {              \
 879                 int _____i;                                             \
 880                 for (_____i = 0; _____i < pg->index; _____i++) {        \
 881                         rec = &pg->records[_____i];
 882
 883 #define while_for_each_ftrace_rec()             \
 884                 }                               \
 885         }
 886
 887 #ifdef CONFIG_KPROBES
 888
 889 static int frozen_record_count;
 890
 891 static inline void freeze_record(struct dyn_ftrace *rec)
 892 {
 893         if (!(rec->flags & FTRACE_FL_FROZEN)) {
 894                 rec->flags |= FTRACE_FL_FROZEN;
 895                 frozen_record_count++;
 896         }
 897 }
 898
 899 static inline void unfreeze_record(struct dyn_ftrace *rec)
 900 {
 901         if (rec->flags & FTRACE_FL_FROZEN) {
 902                 rec->flags &= ~FTRACE_FL_FROZEN;
 903                 frozen_record_count--;
 904         }
 905 }
 906
 907 static inline int record_frozen(struct dyn_ftrace *rec)
 908 {
 909         return rec->flags & FTRACE_FL_FROZEN;
 910 }
 911 #else
 912 # define freeze_record(rec)                     ({ 0; })
 913 # define unfreeze_record(rec)                   ({ 0; })
 914 # define record_frozen(rec)                     ({ 0; })
 915 #endif /* CONFIG_KPROBES */
 916
 917 static void ftrace_free_rec(struct dyn_ftrace *rec)
 918 {
 919         rec->freelist = ftrace_free_records;
 920         ftrace_free_records = rec;
 921         rec->flags |= FTRACE_FL_FREE;
 922 }
 923
 924 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
 925 {
 926         struct dyn_ftrace *rec;
 927
 928         /* First check for freed records */
 929         if (ftrace_free_records) {
 930                 rec = ftrace_free_records;
 931
 932                 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
 933                         FTRACE_WARN_ON_ONCE(1);
 934                         ftrace_free_records = NULL;
 935                         return NULL;
 936                 }
 937
 938                 ftrace_free_records = rec->freelist;
 939                 memset(rec, 0, sizeof(*rec));
 940                 return rec;
 941         }
 942
 943         if (ftrace_pages->index == ENTRIES_PER_PAGE) {
 944                 if (!ftrace_pages->next) {
 945                         /* allocate another page */
 946                         ftrace_pages->next =
 947                                 (void *)get_zeroed_page(GFP_KERNEL);
 948                         if (!ftrace_pages->next)
 949                                 return NULL;
 950                 }
 951                 ftrace_pages = ftrace_pages->next;
 952         }
 953
 954         return &ftrace_pages->records[ftrace_pages->index++];
 955 }
 956
 957 static struct dyn_ftrace *
 958 ftrace_record_ip(unsigned long ip)
 959 {
 960         struct dyn_ftrace *rec;
 961
 962         if (ftrace_disabled)
 963                 return NULL;
 964
 965         rec = ftrace_alloc_dyn_node(ip);
 966         if (!rec)
 967                 return NULL;
 968
 969         rec->ip = ip;
 970         rec->newlist = ftrace_new_addrs;
 971         ftrace_new_addrs = rec;
 972
 973         return rec;
 974 }
 975
 976 static void print_ip_ins(const char *fmt, unsigned char *p)
 977 {
 978         int i;
 979
 980         printk(KERN_CONT "%s", fmt);
 981
 982         for (i = 0; i < MCOUNT_INSN_SIZE; i++)
 983                 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
 984 }
 985
 986 static void ftrace_bug(int failed, unsigned long ip)
 987 {
 988         switch (failed) {
 989         case -EFAULT:
 990                 FTRACE_WARN_ON_ONCE(1);
 991                 pr_info("ftrace faulted on modifying ");
 992                 print_ip_sym(ip);
 993                 break;
 994         case -EINVAL:
 995                 FTRACE_WARN_ON_ONCE(1);
 996                 pr_info("ftrace failed to modify ");
 997                 print_ip_sym(ip);
 998                 print_ip_ins(" actual: ", (unsigned char *)ip);
 999                 printk(KERN_CONT "\n");
1000                 break;
1001         case -EPERM:
1002                 FTRACE_WARN_ON_ONCE(1);
1003                 pr_info("ftrace faulted on writing ");
1004                 print_ip_sym(ip);
1005                 break;
1006         default:
1007                 FTRACE_WARN_ON_ONCE(1);
1008                 pr_info("ftrace faulted on unknown error ");
1009                 print_ip_sym(ip);
1010         }
1011 }
1012
1013
1014 static int
1015 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1016 {
1017         unsigned long ftrace_addr;
1018         unsigned long ip, fl;
1019
1020         ftrace_addr = (unsigned long)FTRACE_ADDR;
1021
1022         ip = rec->ip;
1023
1024         /*
1025          * If this record is not to be traced and
1026          * it is not enabled then do nothing.
1027          *
1028          * If this record is not to be traced and
1029          * it is enabled then disable it.
1030          *
1031          */
1032         if (rec->flags & FTRACE_FL_NOTRACE) {
1033                 if (rec->flags & FTRACE_FL_ENABLED)
1034                         rec->flags &= ~FTRACE_FL_ENABLED;
1035                 else
1036                         return 0;
1037
1038         } else if (ftrace_filtered && enable) {
1039                 /*
1040                  * Filtering is on:
1041                  */
1042
1043                 fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED);
1044
1045                 /* Record is filtered and enabled, do nothing */
1046                 if (fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED))
1047                         return 0;
1048
1049                 /* Record is not filtered or enabled, do nothing */
1050                 if (!fl)
1051                         return 0;
1052
1053                 /* Record is not filtered but enabled, disable it */
1054                 if (fl == FTRACE_FL_ENABLED)
1055                         rec->flags &= ~FTRACE_FL_ENABLED;
1056                 else
1057                 /* Otherwise record is filtered but not enabled, enable it */
1058                         rec->flags |= FTRACE_FL_ENABLED;
1059         } else {
1060                 /* Disable or not filtered */
1061
1062                 if (enable) {
1063                         /* if record is enabled, do nothing */
1064                         if (rec->flags & FTRACE_FL_ENABLED)
1065                                 return 0;
1066
1067                         rec->flags |= FTRACE_FL_ENABLED;
1068
1069                 } else {
1070
1071                         /* if record is not enabled, do nothing */
1072                         if (!(rec->flags & FTRACE_FL_ENABLED))
1073                                 return 0;
1074
1075                         rec->flags &= ~FTRACE_FL_ENABLED;
1076                 }
1077         }
1078
1079         if (rec->flags & FTRACE_FL_ENABLED)
1080                 return ftrace_make_call(rec, ftrace_addr);
1081         else
1082                 return ftrace_make_nop(NULL, rec, ftrace_addr);
1083 }
1084
1085 static void ftrace_replace_code(int enable)
1086 {
1087         struct dyn_ftrace *rec;
1088         struct ftrace_page *pg;
1089         int failed;
1090
1091         do_for_each_ftrace_rec(pg, rec) {
1092                 /*
1093                  * Skip over free records, records that have
1094                  * failed and not converted.
1095                  */
1096                 if (rec->flags & FTRACE_FL_FREE ||
1097                     rec->flags & FTRACE_FL_FAILED ||
1098                     !(rec->flags & FTRACE_FL_CONVERTED))
1099                         continue;
1100
1101                 /* ignore updates to this record's mcount site */
1102                 if (get_kprobe((void *)rec->ip)) {
1103                         freeze_record(rec);
1104                         continue;
1105                 } else {
1106                         unfreeze_record(rec);
1107                 }
1108
1109                 failed = __ftrace_replace_code(rec, enable);
1110                 if (failed) {
1111                         rec->flags |= FTRACE_FL_FAILED;
1112                         if ((system_state == SYSTEM_BOOTING) ||
1113                             !core_kernel_text(rec->ip)) {
1114                                 ftrace_free_rec(rec);
1115                                 } else {
1116                                 ftrace_bug(failed, rec->ip);
1117                                         /* Stop processing */
1118                                         return;
1119                                 }
1120                 }
1121         } while_for_each_ftrace_rec();
1122 }
1123
1124 static int
1125 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1126 {
1127         unsigned long ip;
1128         int ret;
1129
1130         ip = rec->ip;
1131
1132         ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1133         if (ret) {
1134                 ftrace_bug(ret, ip);
1135                 rec->flags |= FTRACE_FL_FAILED;
1136                 return 0;
1137         }
1138         return 1;
1139 }
1140
1141 /*
1142  * archs can override this function if they must do something
1143  * before the modifying code is performed.
1144  */
1145 int __weak ftrace_arch_code_modify_prepare(void)
1146 {
1147         return 0;
1148 }
1149
1150 /*
1151  * archs can override this function if they must do something
1152  * after the modifying code is performed.
1153  */
1154 int __weak ftrace_arch_code_modify_post_process(void)
1155 {
1156         return 0;
1157 }
1158
1159 static int __ftrace_modify_code(void *data)
1160 {
1161         int *command = data;
1162
1163         if (*command & FTRACE_ENABLE_CALLS)
1164                 ftrace_replace_code(1);
1165         else if (*command & FTRACE_DISABLE_CALLS)
1166                 ftrace_replace_code(0);
1167
1168         if (*command & FTRACE_UPDATE_TRACE_FUNC)
1169                 ftrace_update_ftrace_func(ftrace_trace_function);
1170
1171         if (*command & FTRACE_START_FUNC_RET)
1172                 ftrace_enable_ftrace_graph_caller();
1173         else if (*command & FTRACE_STOP_FUNC_RET)
1174                 ftrace_disable_ftrace_graph_caller();
1175
1176         return 0;
1177 }
1178
1179 static void ftrace_run_update_code(int command)
1180 {
1181         int ret;
1182
1183         ret = ftrace_arch_code_modify_prepare();
1184         FTRACE_WARN_ON(ret);
1185         if (ret)
1186                 return;
1187
1188         stop_machine(__ftrace_modify_code, &command, NULL);
1189
1190         ret = ftrace_arch_code_modify_post_process();
1191         FTRACE_WARN_ON(ret);
1192 }
1193
1194 static ftrace_func_t saved_ftrace_func;
1195 static int ftrace_start_up;
1196
1197 static void ftrace_startup_enable(int command)
1198 {
1199         if (saved_ftrace_func != ftrace_trace_function) {
1200                 saved_ftrace_func = ftrace_trace_function;
1201                 command |= FTRACE_UPDATE_TRACE_FUNC;
1202         }
1203
1204         if (!command || !ftrace_enabled)
1205                 return;
1206
1207         ftrace_run_update_code(command);
1208 }
1209
1210 static void ftrace_startup(int command)
1211 {
1212         if (unlikely(ftrace_disabled))
1213                 return;
1214
1215         ftrace_start_up++;
1216         command |= FTRACE_ENABLE_CALLS;
1217
1218         ftrace_startup_enable(command);
1219 }
1220
1221 static void ftrace_shutdown(int command)
1222 {
1223         if (unlikely(ftrace_disabled))
1224                 return;
1225
1226         ftrace_start_up--;
1227         /*
1228          * Just warn in case of unbalance, no need to kill ftrace, it's not
1229          * critical but the ftrace_call callers may be never nopped again after
1230          * further ftrace uses.
1231          */
1232         WARN_ON_ONCE(ftrace_start_up < 0);
1233
1234         if (!ftrace_start_up)
1235                 command |= FTRACE_DISABLE_CALLS;
1236
1237         if (saved_ftrace_func != ftrace_trace_function) {
1238                 saved_ftrace_func = ftrace_trace_function;
1239                 command |= FTRACE_UPDATE_TRACE_FUNC;
1240         }
1241
1242         if (!command || !ftrace_enabled)
1243                 return;
1244
1245         ftrace_run_update_code(command);
1246 }
1247
1248 static void ftrace_startup_sysctl(void)
1249 {
1250         int command = FTRACE_ENABLE_MCOUNT;
1251
1252         if (unlikely(ftrace_disabled))
1253                 return;
1254
1255         /* Force update next time */
1256         saved_ftrace_func = NULL;
1257         /* ftrace_start_up is true if we want ftrace running */
1258         if (ftrace_start_up)
1259                 command |= FTRACE_ENABLE_CALLS;
1260
1261         ftrace_run_update_code(command);
1262 }
1263
1264 static void ftrace_shutdown_sysctl(void)
1265 {
1266         int command = FTRACE_DISABLE_MCOUNT;
1267
1268         if (unlikely(ftrace_disabled))
1269                 return;
1270
1271         /* ftrace_start_up is true if ftrace is running */
1272         if (ftrace_start_up)
1273                 command |= FTRACE_DISABLE_CALLS;
1274
1275         ftrace_run_update_code(command);
1276 }
1277
1278 static cycle_t          ftrace_update_time;
1279 static unsigned long    ftrace_update_cnt;
1280 unsigned long           ftrace_update_tot_cnt;
1281
1282 static int ftrace_update_code(struct module *mod)
1283 {
1284         struct dyn_ftrace *p;
1285         cycle_t start, stop;
1286
1287         start = ftrace_now(raw_smp_processor_id());
1288         ftrace_update_cnt = 0;
1289
1290         while (ftrace_new_addrs) {
1291
1292                 /* If something went wrong, bail without enabling anything */
1293                 if (unlikely(ftrace_disabled))
1294                         return -1;
1295
1296                 p = ftrace_new_addrs;
1297                 ftrace_new_addrs = p->newlist;
1298                 p->flags = 0L;
1299
1300                 /* convert record (i.e, patch mcount-call with NOP) */
1301                 if (ftrace_code_disable(mod, p)) {
1302                         p->flags |= FTRACE_FL_CONVERTED;
1303                         ftrace_update_cnt++;
1304                 } else
1305                         ftrace_free_rec(p);
1306         }
1307
1308         stop = ftrace_now(raw_smp_processor_id());
1309         ftrace_update_time = stop - start;
1310         ftrace_update_tot_cnt += ftrace_update_cnt;
1311
1312         return 0;
1313 }
1314
1315 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
1316 {
1317         struct ftrace_page *pg;
1318         int cnt;
1319         int i;
1320
1321         /* allocate a few pages */
1322         ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
1323         if (!ftrace_pages_start)
1324                 return -1;
1325
1326         /*
1327          * Allocate a few more pages.
1328          *
1329          * TODO: have some parser search vmlinux before
1330          *   final linking to find all calls to ftrace.
1331          *   Then we can:
1332          *    a) know how many pages to allocate.
1333          *     and/or
1334          *    b) set up the table then.
1335          *
1336          *  The dynamic code is still necessary for
1337          *  modules.
1338          */
1339
1340         pg = ftrace_pages = ftrace_pages_start;
1341
1342         cnt = num_to_init / ENTRIES_PER_PAGE;
1343         pr_info("ftrace: allocating %ld entries in %d pages\n",
1344                 num_to_init, cnt + 1);
1345
1346         for (i = 0; i < cnt; i++) {
1347                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
1348
1349                 /* If we fail, we'll try later anyway */
1350                 if (!pg->next)
1351                         break;
1352
1353                 pg = pg->next;
1354         }
1355
1356         return 0;
1357 }
1358
1359 enum {
1360         FTRACE_ITER_FILTER      = (1 << 0),
1361         FTRACE_ITER_CONT        = (1 << 1),
1362         FTRACE_ITER_NOTRACE     = (1 << 2),
1363         FTRACE_ITER_FAILURES    = (1 << 3),
1364         FTRACE_ITER_PRINTALL    = (1 << 4),
1365         FTRACE_ITER_HASH        = (1 << 5),
1366 };
1367
1368 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1369
1370 struct ftrace_iterator {
1371         struct ftrace_page      *pg;
1372         int                     hidx;
1373         int                     idx;
1374         unsigned                flags;
1375         unsigned char           buffer[FTRACE_BUFF_MAX+1];
1376         unsigned                buffer_idx;
1377         unsigned                filtered;
1378 };
1379
1380 static void *
1381 t_hash_next(struct seq_file *m, void *v, loff_t *pos)
1382 {
1383         struct ftrace_iterator *iter = m->private;
1384         struct hlist_node *hnd = v;
1385         struct hlist_head *hhd;
1386
1387         WARN_ON(!(iter->flags & FTRACE_ITER_HASH));
1388
1389         (*pos)++;
1390
1391  retry:
1392         if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
1393                 return NULL;
1394
1395         hhd = &ftrace_func_hash[iter->hidx];
1396
1397         if (hlist_empty(hhd)) {
1398                 iter->hidx++;
1399                 hnd = NULL;
1400                 goto retry;
1401         }
1402
1403         if (!hnd)
1404                 hnd = hhd->first;
1405         else {
1406                 hnd = hnd->next;
1407                 if (!hnd) {
1408                         iter->hidx++;
1409                         goto retry;
1410                 }
1411         }
1412
1413         return hnd;
1414 }
1415
1416 static void *t_hash_start(struct seq_file *m, loff_t *pos)
1417 {
1418         struct ftrace_iterator *iter = m->private;
1419         void *p = NULL;
1420         loff_t l;
1421
1422         if (!(iter->flags & FTRACE_ITER_HASH))
1423                 *pos = 0;
1424
1425         iter->flags |= FTRACE_ITER_HASH;
1426
1427         iter->hidx = 0;
1428         for (l = 0; l <= *pos; ) {
1429                 p = t_hash_next(m, p, &l);
1430                 if (!p)
1431                         break;
1432         }
1433         return p;
1434 }
1435
1436 static int t_hash_show(struct seq_file *m, void *v)
1437 {
1438         struct ftrace_func_probe *rec;
1439         struct hlist_node *hnd = v;
1440         char str[KSYM_SYMBOL_LEN];
1441
1442         rec = hlist_entry(hnd, struct ftrace_func_probe, node);
1443
1444         if (rec->ops->print)
1445                 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
1446
1447         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1448         seq_printf(m, "%s:", str);
1449
1450         kallsyms_lookup((unsigned long)rec->ops->func, NULL, NULL, NULL, str);
1451         seq_printf(m, "%s", str);
1452
1453         if (rec->data)
1454                 seq_printf(m, ":%p", rec->data);
1455         seq_putc(m, '\n');
1456
1457         return 0;
1458 }
1459
1460 static void *
1461 t_next(struct seq_file *m, void *v, loff_t *pos)
1462 {
1463         struct ftrace_iterator *iter = m->private;
1464         struct dyn_ftrace *rec = NULL;
1465
1466         if (iter->flags & FTRACE_ITER_HASH)
1467                 return t_hash_next(m, v, pos);
1468
1469         (*pos)++;
1470
1471         if (iter->flags & FTRACE_ITER_PRINTALL)
1472                 return NULL;
1473
1474  retry:
1475         if (iter->idx >= iter->pg->index) {
1476                 if (iter->pg->next) {
1477                         iter->pg = iter->pg->next;
1478                         iter->idx = 0;
1479                         goto retry;
1480                 }
1481         } else {
1482                 rec = &iter->pg->records[iter->idx++];
1483                 if ((rec->flags & FTRACE_FL_FREE) ||
1484
1485                     (!(iter->flags & FTRACE_ITER_FAILURES) &&
1486                      (rec->flags & FTRACE_FL_FAILED)) ||
1487
1488                     ((iter->flags & FTRACE_ITER_FAILURES) &&
1489                      !(rec->flags & FTRACE_FL_FAILED)) ||
1490
1491                     ((iter->flags & FTRACE_ITER_FILTER) &&
1492                      !(rec->flags & FTRACE_FL_FILTER)) ||
1493
1494                     ((iter->flags & FTRACE_ITER_NOTRACE) &&
1495                      !(rec->flags & FTRACE_FL_NOTRACE))) {
1496                         rec = NULL;
1497                         goto retry;
1498                 }
1499         }
1500
1501         return rec;
1502 }
1503
1504 static void *t_start(struct seq_file *m, loff_t *pos)
1505 {
1506         struct ftrace_iterator *iter = m->private;
1507         void *p = NULL;
1508         loff_t l;
1509
1510         mutex_lock(&ftrace_lock);
1511         /*
1512          * For set_ftrace_filter reading, if we have the filter
1513          * off, we can short cut and just print out that all
1514          * functions are enabled.
1515          */
1516         if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) {
1517                 if (*pos > 0)
1518                         return t_hash_start(m, pos);
1519                 iter->flags |= FTRACE_ITER_PRINTALL;
1520                 return iter;
1521         }
1522
1523         if (iter->flags & FTRACE_ITER_HASH)
1524                 return t_hash_start(m, pos);
1525
1526         iter->pg = ftrace_pages_start;
1527         iter->idx = 0;
1528         for (l = 0; l <= *pos; ) {
1529                 p = t_next(m, p, &l);
1530                 if (!p)
1531                         break;
1532         }
1533
1534         if (!p && iter->flags & FTRACE_ITER_FILTER)
1535                 return t_hash_start(m, pos);
1536
1537         return p;
1538 }
1539
1540 static void t_stop(struct seq_file *m, void *p)
1541 {
1542         mutex_unlock(&ftrace_lock);
1543 }
1544
1545 static int t_show(struct seq_file *m, void *v)
1546 {
1547         struct ftrace_iterator *iter = m->private;
1548         struct dyn_ftrace *rec = v;
1549         char str[KSYM_SYMBOL_LEN];
1550
1551         if (iter->flags & FTRACE_ITER_HASH)
1552                 return t_hash_show(m, v);
1553
1554         if (iter->flags & FTRACE_ITER_PRINTALL) {
1555                 seq_printf(m, "#### all functions enabled ####\n");
1556                 return 0;
1557         }
1558
1559         if (!rec)
1560                 return 0;
1561
1562         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1563
1564         seq_printf(m, "%s\n", str);
1565
1566         return 0;
1567 }
1568
1569 static struct seq_operations show_ftrace_seq_ops = {
1570         .start = t_start,
1571         .next = t_next,
1572         .stop = t_stop,
1573         .show = t_show,
1574 };
1575
1576 static int
1577 ftrace_avail_open(struct inode *inode, struct file *file)
1578 {
1579         struct ftrace_iterator *iter;
1580         int ret;
1581
1582         if (unlikely(ftrace_disabled))
1583                 return -ENODEV;
1584
1585         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1586         if (!iter)
1587                 return -ENOMEM;
1588
1589         iter->pg = ftrace_pages_start;
1590
1591         ret = seq_open(file, &show_ftrace_seq_ops);
1592         if (!ret) {
1593                 struct seq_file *m = file->private_data;
1594
1595                 m->private = iter;
1596         } else {
1597                 kfree(iter);
1598         }
1599
1600         return ret;
1601 }
1602
1603 int ftrace_avail_release(struct inode *inode, struct file *file)
1604 {
1605         struct seq_file *m = (struct seq_file *)file->private_data;
1606         struct ftrace_iterator *iter = m->private;
1607
1608         seq_release(inode, file);
1609         kfree(iter);
1610
1611         return 0;
1612 }
1613
1614 static int
1615 ftrace_failures_open(struct inode *inode, struct file *file)
1616 {
1617         int ret;
1618         struct seq_file *m;
1619         struct ftrace_iterator *iter;
1620
1621         ret = ftrace_avail_open(inode, file);
1622         if (!ret) {
1623                 m = (struct seq_file *)file->private_data;
1624                 iter = (struct ftrace_iterator *)m->private;
1625                 iter->flags = FTRACE_ITER_FAILURES;
1626         }
1627
1628         return ret;
1629 }
1630
1631
1632 static void ftrace_filter_reset(int enable)
1633 {
1634         struct ftrace_page *pg;
1635         struct dyn_ftrace *rec;
1636         unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1637
1638         mutex_lock(&ftrace_lock);
1639         if (enable)
1640                 ftrace_filtered = 0;
1641         do_for_each_ftrace_rec(pg, rec) {
1642                 if (rec->flags & FTRACE_FL_FAILED)
1643                         continue;
1644                 rec->flags &= ~type;
1645         } while_for_each_ftrace_rec();
1646         mutex_unlock(&ftrace_lock);
1647 }
1648
1649 static int
1650 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
1651 {
1652         struct ftrace_iterator *iter;
1653         int ret = 0;
1654
1655         if (unlikely(ftrace_disabled))
1656                 return -ENODEV;
1657
1658         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1659         if (!iter)
1660                 return -ENOMEM;
1661
1662         mutex_lock(&ftrace_regex_lock);
1663         if ((file->f_mode & FMODE_WRITE) &&
1664             !(file->f_flags & O_APPEND))
1665                 ftrace_filter_reset(enable);
1666
1667         if (file->f_mode & FMODE_READ) {
1668                 iter->pg = ftrace_pages_start;
1669                 iter->flags = enable ? FTRACE_ITER_FILTER :
1670                         FTRACE_ITER_NOTRACE;
1671
1672                 ret = seq_open(file, &show_ftrace_seq_ops);
1673                 if (!ret) {
1674                         struct seq_file *m = file->private_data;
1675                         m->private = iter;
1676                 } else
1677                         kfree(iter);
1678         } else
1679                 file->private_data = iter;
1680         mutex_unlock(&ftrace_regex_lock);
1681
1682         return ret;
1683 }
1684
1685 static int
1686 ftrace_filter_open(struct inode *inode, struct file *file)
1687 {
1688         return ftrace_regex_open(inode, file, 1);
1689 }
1690
1691 static int
1692 ftrace_notrace_open(struct inode *inode, struct file *file)
1693 {
1694         return ftrace_regex_open(inode, file, 0);
1695 }
1696
1697 static loff_t
1698 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1699 {
1700         loff_t ret;
1701
1702         if (file->f_mode & FMODE_READ)
1703                 ret = seq_lseek(file, offset, origin);
1704         else
1705                 file->f_pos = ret = 1;
1706
1707         return ret;
1708 }
1709
1710 enum {
1711         MATCH_FULL,
1712         MATCH_FRONT_ONLY,
1713         MATCH_MIDDLE_ONLY,
1714         MATCH_END_ONLY,
1715 };
1716
1717 /*
1718  * (static function - no need for kernel doc)
1719  *
1720  * Pass in a buffer containing a glob and this function will
1721  * set search to point to the search part of the buffer and
1722  * return the type of search it is (see enum above).
1723  * This does modify buff.
1724  *
1725  * Returns enum type.
1726  *  search returns the pointer to use for comparison.
1727  *  not returns 1 if buff started with a '!'
1728  *     0 otherwise.
1729  */
1730 static int
1731 ftrace_setup_glob(char *buff, int len, char **search, int *not)
1732 {
1733         int type = MATCH_FULL;
1734         int i;
1735
1736         if (buff[0] == '!') {
1737                 *not = 1;
1738                 buff++;
1739                 len--;
1740         } else
1741                 *not = 0;
1742
1743         *search = buff;
1744
1745         for (i = 0; i < len; i++) {
1746                 if (buff[i] == '*') {
1747                         if (!i) {
1748                                 *search = buff + 1;
1749                                 type = MATCH_END_ONLY;
1750                         } else {
1751                                 if (type == MATCH_END_ONLY)
1752                                         type = MATCH_MIDDLE_ONLY;
1753                                 else
1754                                         type = MATCH_FRONT_ONLY;
1755                                 buff[i] = 0;
1756                                 break;
1757                         }
1758                 }
1759         }
1760
1761         return type;
1762 }
1763
1764 static int ftrace_match(char *str, char *regex, int len, int type)
1765 {
1766         int matched = 0;
1767         char *ptr;
1768
1769         switch (type) {
1770         case MATCH_FULL:
1771                 if (strcmp(str, regex) == 0)
1772                         matched = 1;
1773                 break;
1774         case MATCH_FRONT_ONLY:
1775                 if (strncmp(str, regex, len) == 0)
1776                         matched = 1;
1777                 break;
1778         case MATCH_MIDDLE_ONLY:
1779                 if (strstr(str, regex))
1780                         matched = 1;
1781                 break;
1782         case MATCH_END_ONLY:
1783                 ptr = strstr(str, regex);
1784                 if (ptr && (ptr[len] == 0))
1785                         matched = 1;
1786                 break;
1787         }
1788
1789         return matched;
1790 }
1791
1792 static int
1793 ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
1794 {
1795         char str[KSYM_SYMBOL_LEN];
1796
1797         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1798         return ftrace_match(str, regex, len, type);
1799 }
1800
1801 static void ftrace_match_records(char *buff, int len, int enable)
1802 {
1803         unsigned int search_len;
1804         struct ftrace_page *pg;
1805         struct dyn_ftrace *rec;
1806         unsigned long flag;
1807         char *search;
1808         int type;
1809         int not;
1810
1811         flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1812         type = ftrace_setup_glob(buff, len, &search, &not);
1813
1814         search_len = strlen(search);
1815
1816         mutex_lock(&ftrace_lock);
1817         do_for_each_ftrace_rec(pg, rec) {
1818
1819                 if (rec->flags & FTRACE_FL_FAILED)
1820                         continue;
1821
1822                 if (ftrace_match_record(rec, search, search_len, type)) {
1823                         if (not)
1824                                 rec->flags &= ~flag;
1825                         else
1826                                 rec->flags |= flag;
1827                 }
1828                 /*
1829                  * Only enable filtering if we have a function that
1830                  * is filtered on.
1831                  */
1832                 if (enable && (rec->flags & FTRACE_FL_FILTER))
1833                         ftrace_filtered = 1;
1834         } while_for_each_ftrace_rec();
1835         mutex_unlock(&ftrace_lock);
1836 }
1837
1838 static int
1839 ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
1840                            char *regex, int len, int type)
1841 {
1842         char str[KSYM_SYMBOL_LEN];
1843         char *modname;
1844
1845         kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
1846
1847         if (!modname || strcmp(modname, mod))
1848                 return 0;
1849
1850         /* blank search means to match all funcs in the mod */
1851         if (len)
1852                 return ftrace_match(str, regex, len, type);
1853         else
1854                 return 1;
1855 }
1856
1857 static void ftrace_match_module_records(char *buff, char *mod, int enable)
1858 {
1859         unsigned search_len = 0;
1860         struct ftrace_page *pg;
1861         struct dyn_ftrace *rec;
1862         int type = MATCH_FULL;
1863         char *search = buff;
1864         unsigned long flag;
1865         int not = 0;
1866
1867         flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1868
1869         /* blank or '*' mean the same */
1870         if (strcmp(buff, "*") == 0)
1871                 buff[0] = 0;
1872
1873         /* handle the case of 'dont filter this module' */
1874         if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
1875                 buff[0] = 0;
1876                 not = 1;
1877         }
1878
1879         if (strlen(buff)) {
1880                 type = ftrace_setup_glob(buff, strlen(buff), &search, &not);
1881                 search_len = strlen(search);
1882         }
1883
1884         mutex_lock(&ftrace_lock);
1885         do_for_each_ftrace_rec(pg, rec) {
1886
1887                 if (rec->flags & FTRACE_FL_FAILED)
1888                         continue;
1889
1890                 if (ftrace_match_module_record(rec, mod,
1891                                                search, search_len, type)) {
1892                         if (not)
1893                                 rec->flags &= ~flag;
1894                         else
1895                                 rec->flags |= flag;
1896                 }
1897                 if (enable && (rec->flags & FTRACE_FL_FILTER))
1898                         ftrace_filtered = 1;
1899
1900         } while_for_each_ftrace_rec();
1901         mutex_unlock(&ftrace_lock);
1902 }
1903
1904 /*
1905  * We register the module command as a template to show others how
1906  * to register the a command as well.
1907  */
1908
1909 static int
1910 ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
1911 {
1912         char *mod;
1913
1914         /*
1915          * cmd == 'mod' because we only registered this func
1916          * for the 'mod' ftrace_func_command.
1917          * But if you register one func with multiple commands,
1918          * you can tell which command was used by the cmd
1919          * parameter.
1920          */
1921
1922         /* we must have a module name */
1923         if (!param)
1924                 return -EINVAL;
1925
1926         mod = strsep(&param, ":");
1927         if (!strlen(mod))
1928                 return -EINVAL;
1929
1930         ftrace_match_module_records(func, mod, enable);
1931         return 0;
1932 }
1933
1934 static struct ftrace_func_command ftrace_mod_cmd = {
1935         .name                   = "mod",
1936         .func                   = ftrace_mod_callback,
1937 };
1938
1939 static int __init ftrace_mod_cmd_init(void)
1940 {
1941         return register_ftrace_command(&ftrace_mod_cmd);
1942 }
1943 device_initcall(ftrace_mod_cmd_init);
1944
1945 static void
1946 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
1947 {
1948         struct ftrace_func_probe *entry;
1949         struct hlist_head *hhd;
1950         struct hlist_node *n;
1951         unsigned long key;
1952         int resched;
1953
1954         key = hash_long(ip, FTRACE_HASH_BITS);
1955
1956         hhd = &ftrace_func_hash[key];
1957
1958         if (hlist_empty(hhd))
1959                 return;
1960
1961         /*
1962          * Disable preemption for these calls to prevent a RCU grace
1963          * period. This syncs the hash iteration and freeing of items
1964          * on the hash. rcu_read_lock is too dangerous here.
1965          */
1966         resched = ftrace_preempt_disable();
1967         hlist_for_each_entry_rcu(entry, n, hhd, node) {
1968                 if (entry->ip == ip)
1969                         entry->ops->func(ip, parent_ip, &entry->data);
1970         }
1971         ftrace_preempt_enable(resched);
1972 }
1973
1974 static struct ftrace_ops trace_probe_ops __read_mostly =
1975 {
1976         .func           = function_trace_probe_call,
1977 };
1978
1979 static int ftrace_probe_registered;
1980
1981 static void __enable_ftrace_function_probe(void)
1982 {
1983         int i;
1984
1985         if (ftrace_probe_registered)
1986                 return;
1987
1988         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1989                 struct hlist_head *hhd = &ftrace_func_hash[i];
1990                 if (hhd->first)
1991                         break;
1992         }
1993         /* Nothing registered? */
1994         if (i == FTRACE_FUNC_HASHSIZE)
1995                 return;
1996
1997         __register_ftrace_function(&trace_probe_ops);
1998         ftrace_startup(0);
1999         ftrace_probe_registered = 1;
2000 }
2001
2002 static void __disable_ftrace_function_probe(void)
2003 {
2004         int i;
2005
2006         if (!ftrace_probe_registered)
2007                 return;
2008
2009         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2010                 struct hlist_head *hhd = &ftrace_func_hash[i];
2011                 if (hhd->first)
2012                         return;
2013         }
2014
2015         /* no more funcs left */
2016         __unregister_ftrace_function(&trace_probe_ops);
2017         ftrace_shutdown(0);
2018         ftrace_probe_registered = 0;
2019 }
2020
2021
2022 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
2023 {
2024         struct ftrace_func_probe *entry =
2025                 container_of(rhp, struct ftrace_func_probe, rcu);
2026
2027         if (entry->ops->free)
2028                 entry->ops->free(&entry->data);
2029         kfree(entry);
2030 }
2031
2032
2033 int
2034 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2035                               void *data)
2036 {
2037         struct ftrace_func_probe *entry;
2038         struct ftrace_page *pg;
2039         struct dyn_ftrace *rec;
2040         int type, len, not;
2041         unsigned long key;
2042         int count = 0;
2043         char *search;
2044
2045         type = ftrace_setup_glob(glob, strlen(glob), &search, &not);
2046         len = strlen(search);
2047
2048         /* we do not support '!' for function probes */
2049         if (WARN_ON(not))
2050                 return -EINVAL;
2051
2052         mutex_lock(&ftrace_lock);
2053         do_for_each_ftrace_rec(pg, rec) {
2054
2055                 if (rec->flags & FTRACE_FL_FAILED)
2056                         continue;
2057
2058                 if (!ftrace_match_record(rec, search, len, type))
2059                         continue;
2060
2061                 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2062                 if (!entry) {
2063                         /* If we did not process any, then return error */
2064                         if (!count)
2065                                 count = -ENOMEM;
2066                         goto out_unlock;
2067                 }
2068
2069                 count++;
2070
2071                 entry->data = data;
2072
2073                 /*
2074                  * The caller might want to do something special
2075                  * for each function we find. We call the callback
2076                  * to give the caller an opportunity to do so.
2077                  */
2078                 if (ops->callback) {
2079                         if (ops->callback(rec->ip, &entry->data) < 0) {
2080                                 /* caller does not like this func */
2081                                 kfree(entry);
2082                                 continue;
2083                         }
2084                 }
2085
2086                 entry->ops = ops;
2087                 entry->ip = rec->ip;
2088
2089                 key = hash_long(entry->ip, FTRACE_HASH_BITS);
2090                 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
2091
2092         } while_for_each_ftrace_rec();
2093         __enable_ftrace_function_probe();
2094
2095  out_unlock:
2096         mutex_unlock(&ftrace_lock);
2097
2098         return count;
2099 }
2100
2101 enum {
2102         PROBE_TEST_FUNC         = 1,
2103         PROBE_TEST_DATA         = 2
2104 };
2105
2106 static void
2107 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2108                                   void *data, int flags)
2109 {
2110         struct ftrace_func_probe *entry;
2111         struct hlist_node *n, *tmp;
2112         char str[KSYM_SYMBOL_LEN];
2113         int type = MATCH_FULL;
2114         int i, len = 0;
2115         char *search;
2116
2117         if (glob && (strcmp(glob, "*") || !strlen(glob)))
2118                 glob = NULL;
2119         else {
2120                 int not;
2121
2122                 type = ftrace_setup_glob(glob, strlen(glob), &search, &not);
2123                 len = strlen(search);
2124
2125                 /* we do not support '!' for function probes */
2126                 if (WARN_ON(not))
2127                         return;
2128         }
2129
2130         mutex_lock(&ftrace_lock);
2131         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2132                 struct hlist_head *hhd = &ftrace_func_hash[i];
2133
2134                 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
2135
2136                         /* break up if statements for readability */
2137                         if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2138                                 continue;
2139
2140                         if ((flags & PROBE_TEST_DATA) && entry->data != data)
2141                                 continue;
2142
2143                         /* do this last, since it is the most expensive */
2144                         if (glob) {
2145                                 kallsyms_lookup(entry->ip, NULL, NULL,
2146                                                 NULL, str);
2147                                 if (!ftrace_match(str, glob, len, type))
2148                                         continue;
2149                         }
2150
2151                         hlist_del(&entry->node);
2152                         call_rcu(&entry->rcu, ftrace_free_entry_rcu);
2153                 }
2154         }
2155         __disable_ftrace_function_probe();
2156         mutex_unlock(&ftrace_lock);
2157 }
2158
2159 void
2160 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2161                                 void *data)
2162 {
2163         __unregister_ftrace_function_probe(glob, ops, data,
2164                                           PROBE_TEST_FUNC | PROBE_TEST_DATA);
2165 }
2166
2167 void
2168 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
2169 {
2170         __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
2171 }
2172
2173 void unregister_ftrace_function_probe_all(char *glob)
2174 {
2175         __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
2176 }
2177
2178 static LIST_HEAD(ftrace_commands);
2179 static DEFINE_MUTEX(ftrace_cmd_mutex);
2180
2181 int register_ftrace_command(struct ftrace_func_command *cmd)
2182 {
2183         struct ftrace_func_command *p;
2184         int ret = 0;
2185
2186         mutex_lock(&ftrace_cmd_mutex);
2187         list_for_each_entry(p, &ftrace_commands, list) {
2188                 if (strcmp(cmd->name, p->name) == 0) {
2189                         ret = -EBUSY;
2190                         goto out_unlock;
2191                 }
2192         }
2193         list_add(&cmd->list, &ftrace_commands);
2194  out_unlock:
2195         mutex_unlock(&ftrace_cmd_mutex);
2196
2197         return ret;
2198 }
2199
2200 int unregister_ftrace_command(struct ftrace_func_command *cmd)
2201 {
2202         struct ftrace_func_command *p, *n;
2203         int ret = -ENODEV;
2204
2205         mutex_lock(&ftrace_cmd_mutex);
2206         list_for_each_entry_safe(p, n, &ftrace_commands, list) {
2207                 if (strcmp(cmd->name, p->name) == 0) {
2208                         ret = 0;
2209                         list_del_init(&p->list);
2210                         goto out_unlock;
2211                 }
2212         }
2213  out_unlock:
2214         mutex_unlock(&ftrace_cmd_mutex);
2215
2216         return ret;
2217 }
2218
2219 static int ftrace_process_regex(char *buff, int len, int enable)
2220 {
2221         char *func, *command, *next = buff;
2222         struct ftrace_func_command *p;
2223         int ret = -EINVAL;
2224
2225         func = strsep(&next, ":");
2226
2227         if (!next) {
2228                 ftrace_match_records(func, len, enable);
2229                 return 0;
2230         }
2231
2232         /* command found */
2233
2234         command = strsep(&next, ":");
2235
2236         mutex_lock(&ftrace_cmd_mutex);
2237         list_for_each_entry(p, &ftrace_commands, list) {
2238                 if (strcmp(p->name, command) == 0) {
2239                         ret = p->func(func, command, next, enable);
2240                         goto out_unlock;
2241                 }
2242         }
2243  out_unlock:
2244         mutex_unlock(&ftrace_cmd_mutex);
2245
2246         return ret;
2247 }
2248
2249 static ssize_t
2250 ftrace_regex_write(struct file *file, const char __user *ubuf,
2251                    size_t cnt, loff_t *ppos, int enable)
2252 {
2253         struct ftrace_iterator *iter;
2254         char ch;
2255         size_t read = 0;
2256         ssize_t ret;
2257
2258         if (!cnt || cnt < 0)
2259                 return 0;
2260
2261         mutex_lock(&ftrace_regex_lock);
2262
2263         if (file->f_mode & FMODE_READ) {
2264                 struct seq_file *m = file->private_data;
2265                 iter = m->private;
2266         } else
2267                 iter = file->private_data;
2268
2269         if (!*ppos) {
2270                 iter->flags &= ~FTRACE_ITER_CONT;
2271                 iter->buffer_idx = 0;
2272         }
2273
2274         ret = get_user(ch, ubuf++);
2275         if (ret)
2276                 goto out;
2277         read++;
2278         cnt--;
2279
2280         if (!(iter->flags & ~FTRACE_ITER_CONT)) {
2281                 /* skip white space */
2282                 while (cnt && isspace(ch)) {
2283                         ret = get_user(ch, ubuf++);
2284                         if (ret)
2285                                 goto out;
2286                         read++;
2287                         cnt--;
2288                 }
2289
2290                 if (isspace(ch)) {
2291                         file->f_pos += read;
2292                         ret = read;
2293                         goto out;
2294                 }
2295
2296                 iter->buffer_idx = 0;
2297         }
2298
2299         while (cnt && !isspace(ch)) {
2300                 if (iter->buffer_idx < FTRACE_BUFF_MAX)
2301                         iter->buffer[iter->buffer_idx++] = ch;
2302                 else {
2303                         ret = -EINVAL;
2304                         goto out;
2305                 }
2306                 ret = get_user(ch, ubuf++);
2307                 if (ret)
2308                         goto out;
2309                 read++;
2310                 cnt--;
2311         }
2312
2313         if (isspace(ch)) {
2314                 iter->filtered++;
2315                 iter->buffer[iter->buffer_idx] = 0;
2316                 ret = ftrace_process_regex(iter->buffer,
2317                                            iter->buffer_idx, enable);
2318                 if (ret)
2319                         goto out;
2320                 iter->buffer_idx = 0;
2321         } else
2322                 iter->flags |= FTRACE_ITER_CONT;
2323
2324
2325         file->f_pos += read;
2326
2327         ret = read;
2328  out:
2329         mutex_unlock(&ftrace_regex_lock);
2330
2331         return ret;
2332 }
2333
2334 static ssize_t
2335 ftrace_filter_write(struct file *file, const char __user *ubuf,
2336                     size_t cnt, loff_t *ppos)
2337 {
2338         return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
2339 }
2340
2341 static ssize_t
2342 ftrace_notrace_write(struct file *file, const char __user *ubuf,
2343                      size_t cnt, loff_t *ppos)
2344 {
2345         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
2346 }
2347
2348 static void
2349 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
2350 {
2351         if (unlikely(ftrace_disabled))
2352                 return;
2353
2354         mutex_lock(&ftrace_regex_lock);
2355         if (reset)
2356                 ftrace_filter_reset(enable);
2357         if (buf)
2358                 ftrace_match_records(buf, len, enable);
2359         mutex_unlock(&ftrace_regex_lock);
2360 }
2361
2362 /**
2363  * ftrace_set_filter - set a function to filter on in ftrace
2364  * @buf - the string that holds the function filter text.
2365  * @len - the length of the string.
2366  * @reset - non zero to reset all filters before applying this filter.
2367  *
2368  * Filters denote which functions should be enabled when tracing is enabled.
2369  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2370  */
2371 void ftrace_set_filter(unsigned char *buf, int len, int reset)
2372 {
2373         ftrace_set_regex(buf, len, reset, 1);
2374 }
2375
2376 /**
2377  * ftrace_set_notrace - set a function to not trace in ftrace
2378  * @buf - the string that holds the function notrace text.
2379  * @len - the length of the string.
2380  * @reset - non zero to reset all filters before applying this filter.
2381  *
2382  * Notrace Filters denote which functions should not be enabled when tracing
2383  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2384  * for tracing.
2385  */
2386 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
2387 {
2388         ftrace_set_regex(buf, len, reset, 0);
2389 }
2390
2391 /*
2392  * command line interface to allow users to set filters on boot up.
2393  */
2394 #define FTRACE_FILTER_SIZE              COMMAND_LINE_SIZE
2395 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
2396 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
2397
2398 static int __init set_ftrace_notrace(char *str)
2399 {
2400         strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
2401         return 1;
2402 }
2403 __setup("ftrace_notrace=", set_ftrace_notrace);
2404
2405 static int __init set_ftrace_filter(char *str)
2406 {
2407         strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
2408         return 1;
2409 }
2410 __setup("ftrace_filter=", set_ftrace_filter);
2411
2412 static void __init set_ftrace_early_filter(char *buf, int enable)
2413 {
2414         char *func;
2415
2416         while (buf) {
2417                 func = strsep(&buf, ",");
2418                 ftrace_set_regex(func, strlen(func), 0, enable);
2419         }
2420 }
2421
2422 static void __init set_ftrace_early_filters(void)
2423 {
2424         if (ftrace_filter_buf[0])
2425                 set_ftrace_early_filter(ftrace_filter_buf, 1);
2426         if (ftrace_notrace_buf[0])
2427                 set_ftrace_early_filter(ftrace_notrace_buf, 0);
2428 }
2429
2430 static int
2431 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
2432 {
2433         struct seq_file *m = (struct seq_file *)file->private_data;
2434         struct ftrace_iterator *iter;
2435
2436         mutex_lock(&ftrace_regex_lock);
2437         if (file->f_mode & FMODE_READ) {
2438                 iter = m->private;
2439
2440                 seq_release(inode, file);
2441         } else
2442                 iter = file->private_data;
2443
2444         if (iter->buffer_idx) {
2445                 iter->filtered++;
2446                 iter->buffer[iter->buffer_idx] = 0;
2447                 ftrace_match_records(iter->buffer, iter->buffer_idx, enable);
2448         }
2449
2450         mutex_lock(&ftrace_lock);
2451         if (ftrace_start_up && ftrace_enabled)
2452                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
2453         mutex_unlock(&ftrace_lock);
2454
2455         kfree(iter);
2456         mutex_unlock(&ftrace_regex_lock);
2457         return 0;
2458 }
2459
2460 static int
2461 ftrace_filter_release(struct inode *inode, struct file *file)
2462 {
2463         return ftrace_regex_release(inode, file, 1);
2464 }
2465
2466 static int
2467 ftrace_notrace_release(struct inode *inode, struct file *file)
2468 {
2469         return ftrace_regex_release(inode, file, 0);
2470 }
2471
2472 static const struct file_operations ftrace_avail_fops = {
2473         .open = ftrace_avail_open,
2474         .read = seq_read,
2475         .llseek = seq_lseek,
2476         .release = ftrace_avail_release,
2477 };
2478
2479 static const struct file_operations ftrace_failures_fops = {
2480         .open = ftrace_failures_open,
2481         .read = seq_read,
2482         .llseek = seq_lseek,
2483         .release = ftrace_avail_release,
2484 };
2485
2486 static const struct file_operations ftrace_filter_fops = {
2487         .open = ftrace_filter_open,
2488         .read = seq_read,
2489         .write = ftrace_filter_write,
2490         .llseek = ftrace_regex_lseek,
2491         .release = ftrace_filter_release,
2492 };
2493
2494 static const struct file_operations ftrace_notrace_fops = {
2495         .open = ftrace_notrace_open,
2496         .read = seq_read,
2497         .write = ftrace_notrace_write,
2498         .llseek = ftrace_regex_lseek,
2499         .release = ftrace_notrace_release,
2500 };
2501
2502 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2503
2504 static DEFINE_MUTEX(graph_lock);
2505
2506 int ftrace_graph_count;
2507 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
2508
2509 static void *
2510 __g_next(struct seq_file *m, loff_t *pos)
2511 {
2512         unsigned long *array = m->private;
2513
2514         if (*pos >= ftrace_graph_count)
2515                 return NULL;
2516         return &array[*pos];
2517 }
2518
2519 static void *
2520 g_next(struct seq_file *m, void *v, loff_t *pos)
2521 {
2522         (*pos)++;
2523         return __g_next(m, pos);
2524 }
2525
2526 static void *g_start(struct seq_file *m, loff_t *pos)
2527 {
2528         mutex_lock(&graph_lock);
2529
2530         /* Nothing, tell g_show to print all functions are enabled */
2531         if (!ftrace_graph_count && !*pos)
2532                 return (void *)1;
2533
2534         return __g_next(m, pos);
2535 }
2536
2537 static void g_stop(struct seq_file *m, void *p)
2538 {
2539         mutex_unlock(&graph_lock);
2540 }
2541
2542 static int g_show(struct seq_file *m, void *v)
2543 {
2544         unsigned long *ptr = v;
2545         char str[KSYM_SYMBOL_LEN];
2546
2547         if (!ptr)
2548                 return 0;
2549
2550         if (ptr == (unsigned long *)1) {
2551                 seq_printf(m, "#### all functions enabled ####\n");
2552                 return 0;
2553         }
2554
2555         kallsyms_lookup(*ptr, NULL, NULL, NULL, str);
2556
2557         seq_printf(m, "%s\n", str);
2558
2559         return 0;
2560 }
2561
2562 static struct seq_operations ftrace_graph_seq_ops = {
2563         .start = g_start,
2564         .next = g_next,
2565         .stop = g_stop,
2566         .show = g_show,
2567 };
2568
2569 static int
2570 ftrace_graph_open(struct inode *inode, struct file *file)
2571 {
2572         int ret = 0;
2573
2574         if (unlikely(ftrace_disabled))
2575                 return -ENODEV;
2576
2577         mutex_lock(&graph_lock);
2578         if ((file->f_mode & FMODE_WRITE) &&
2579             !(file->f_flags & O_APPEND)) {
2580                 ftrace_graph_count = 0;
2581                 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
2582         }
2583
2584         if (file->f_mode & FMODE_READ) {
2585                 ret = seq_open(file, &ftrace_graph_seq_ops);
2586                 if (!ret) {
2587                         struct seq_file *m = file->private_data;
2588                         m->private = ftrace_graph_funcs;
2589                 }
2590         } else
2591                 file->private_data = ftrace_graph_funcs;
2592         mutex_unlock(&graph_lock);
2593
2594         return ret;
2595 }
2596
2597 static int
2598 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
2599 {
2600         struct dyn_ftrace *rec;
2601         struct ftrace_page *pg;
2602         int search_len;
2603         int found = 0;
2604         int type, not;
2605         char *search;
2606         bool exists;
2607         int i;
2608
2609         if (ftrace_disabled)
2610                 return -ENODEV;
2611
2612         /* decode regex */
2613         type = ftrace_setup_glob(buffer, strlen(buffer), &search, &not);
2614         if (not)
2615                 return -EINVAL;
2616
2617         search_len = strlen(search);
2618
2619         mutex_lock(&ftrace_lock);
2620         do_for_each_ftrace_rec(pg, rec) {
2621
2622                 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
2623                         break;
2624
2625                 if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
2626                         continue;
2627
2628                 if (ftrace_match_record(rec, search, search_len, type)) {
2629                         /* ensure it is not already in the array */
2630                         exists = false;
2631                         for (i = 0; i < *idx; i++)
2632                                 if (array[i] == rec->ip) {
2633                                         exists = true;
2634                                         break;
2635                                 }
2636                         if (!exists) {
2637                                 array[(*idx)++] = rec->ip;
2638                                 found = 1;
2639                         }
2640                 }
2641         } while_for_each_ftrace_rec();
2642
2643         mutex_unlock(&ftrace_lock);
2644
2645         return found ? 0 : -EINVAL;
2646 }
2647
2648 static ssize_t
2649 ftrace_graph_write(struct file *file, const char __user *ubuf,
2650                    size_t cnt, loff_t *ppos)
2651 {
2652         unsigned char buffer[FTRACE_BUFF_MAX+1];
2653         unsigned long *array;
2654         size_t read = 0;
2655         ssize_t ret;
2656         int index = 0;
2657         char ch;
2658
2659         if (!cnt || cnt < 0)
2660                 return 0;
2661
2662         mutex_lock(&graph_lock);
2663
2664         if (ftrace_graph_count >= FTRACE_GRAPH_MAX_FUNCS) {
2665                 ret = -EBUSY;
2666                 goto out;
2667         }
2668
2669         if (file->f_mode & FMODE_READ) {
2670                 struct seq_file *m = file->private_data;
2671                 array = m->private;
2672         } else
2673                 array = file->private_data;
2674
2675         ret = get_user(ch, ubuf++);
2676         if (ret)
2677                 goto out;
2678         read++;
2679         cnt--;
2680
2681         /* skip white space */
2682         while (cnt && isspace(ch)) {
2683                 ret = get_user(ch, ubuf++);
2684                 if (ret)
2685                         goto out;
2686                 read++;
2687                 cnt--;
2688         }
2689
2690         if (isspace(ch)) {
2691                 *ppos += read;
2692                 ret = read;
2693                 goto out;
2694         }
2695
2696         while (cnt && !isspace(ch)) {
2697                 if (index < FTRACE_BUFF_MAX)
2698                         buffer[index++] = ch;
2699                 else {
2700                         ret = -EINVAL;
2701                         goto out;
2702                 }
2703                 ret = get_user(ch, ubuf++);
2704                 if (ret)
2705                         goto out;
2706                 read++;
2707                 cnt--;
2708         }
2709         buffer[index] = 0;
2710
2711         /* we allow only one expression at a time */
2712         ret = ftrace_set_func(array, &ftrace_graph_count, buffer);
2713         if (ret)
2714                 goto out;
2715
2716         file->f_pos += read;
2717
2718         ret = read;
2719  out:
2720         mutex_unlock(&graph_lock);
2721
2722         return ret;
2723 }
2724
2725 static const struct file_operations ftrace_graph_fops = {
2726         .open = ftrace_graph_open,
2727         .read = seq_read,
2728         .write = ftrace_graph_write,
2729 };
2730 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2731
2732 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
2733 {
2734
2735         trace_create_file("available_filter_functions", 0444,
2736                         d_tracer, NULL, &ftrace_avail_fops);
2737
2738         trace_create_file("failures", 0444,
2739                         d_tracer, NULL, &ftrace_failures_fops);
2740
2741         trace_create_file("set_ftrace_filter", 0644, d_tracer,
2742                         NULL, &ftrace_filter_fops);
2743
2744         trace_create_file("set_ftrace_notrace", 0644, d_tracer,
2745                                     NULL, &ftrace_notrace_fops);
2746
2747 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2748         trace_create_file("set_graph_function", 0444, d_tracer,
2749                                     NULL,
2750                                     &ftrace_graph_fops);
2751 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2752
2753         return 0;
2754 }
2755
2756 static int ftrace_convert_nops(struct module *mod,
2757                                unsigned long *start,
2758                                unsigned long *end)
2759 {
2760         unsigned long *p;
2761         unsigned long addr;
2762         unsigned long flags;
2763
2764         mutex_lock(&ftrace_lock);
2765         p = start;
2766         while (p < end) {
2767                 addr = ftrace_call_adjust(*p++);
2768                 /*
2769                  * Some architecture linkers will pad between
2770                  * the different mcount_loc sections of different
2771                  * object files to satisfy alignments.
2772                  * Skip any NULL pointers.
2773                  */
2774                 if (!addr)
2775                         continue;
2776                 ftrace_record_ip(addr);
2777         }
2778
2779         /* disable interrupts to prevent kstop machine */
2780         local_irq_save(flags);
2781         ftrace_update_code(mod);
2782         local_irq_restore(flags);
2783         mutex_unlock(&ftrace_lock);
2784
2785         return 0;
2786 }
2787
2788 #ifdef CONFIG_MODULES
2789 void ftrace_release(void *start, void *end)
2790 {
2791         struct dyn_ftrace *rec;
2792         struct ftrace_page *pg;
2793         unsigned long s = (unsigned long)start;
2794         unsigned long e = (unsigned long)end;
2795
2796         if (ftrace_disabled || !start || start == end)
2797                 return;
2798
2799         mutex_lock(&ftrace_lock);
2800         do_for_each_ftrace_rec(pg, rec) {
2801                 if ((rec->ip >= s) && (rec->ip < e)) {
2802                         /*
2803                          * rec->ip is changed in ftrace_free_rec()
2804                          * It should not between s and e if record was freed.
2805                          */
2806                         FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
2807                         ftrace_free_rec(rec);
2808                 }
2809         } while_for_each_ftrace_rec();
2810         mutex_unlock(&ftrace_lock);
2811 }
2812
2813 static void ftrace_init_module(struct module *mod,
2814                                unsigned long *start, unsigned long *end)
2815 {
2816         if (ftrace_disabled || start == end)
2817                 return;
2818         ftrace_convert_nops(mod, start, end);
2819 }
2820
2821 static int ftrace_module_notify(struct notifier_block *self,
2822                                 unsigned long val, void *data)
2823 {
2824         struct module *mod = data;
2825
2826         switch (val) {
2827         case MODULE_STATE_COMING:
2828                 ftrace_init_module(mod, mod->ftrace_callsites,
2829                                    mod->ftrace_callsites +
2830                                    mod->num_ftrace_callsites);
2831                 break;
2832         case MODULE_STATE_GOING:
2833                 ftrace_release(mod->ftrace_callsites,
2834                                mod->ftrace_callsites +
2835                                mod->num_ftrace_callsites);
2836                 break;
2837         }
2838
2839         return 0;
2840 }
2841 #else
2842 static int ftrace_module_notify(struct notifier_block *self,
2843                                 unsigned long val, void *data)
2844 {
2845         return 0;
2846 }
2847 #endif /* CONFIG_MODULES */
2848
2849 struct notifier_block ftrace_module_nb = {
2850         .notifier_call = ftrace_module_notify,
2851         .priority = 0,
2852 };
2853
2854 extern unsigned long __start_mcount_loc[];
2855 extern unsigned long __stop_mcount_loc[];
2856
2857 void __init ftrace_init(void)
2858 {
2859         unsigned long count, addr, flags;
2860         int ret;
2861
2862         /* Keep the ftrace pointer to the stub */
2863         addr = (unsigned long)ftrace_stub;
2864
2865         local_irq_save(flags);
2866         ftrace_dyn_arch_init(&addr);
2867         local_irq_restore(flags);
2868
2869         /* ftrace_dyn_arch_init places the return code in addr */
2870         if (addr)
2871                 goto failed;
2872
2873         count = __stop_mcount_loc - __start_mcount_loc;
2874
2875         ret = ftrace_dyn_table_alloc(count);
2876         if (ret)
2877                 goto failed;
2878
2879         last_ftrace_enabled = ftrace_enabled = 1;
2880
2881         ret = ftrace_convert_nops(NULL,
2882                                   __start_mcount_loc,
2883                                   __stop_mcount_loc);
2884
2885         ret = register_module_notifier(&ftrace_module_nb);
2886         if (ret)
2887                 pr_warning("Failed to register trace ftrace module notifier\n");
2888
2889         set_ftrace_early_filters();
2890
2891         return;
2892  failed:
2893         ftrace_disabled = 1;
2894 }
2895
2896 #else
2897
2898 static int __init ftrace_nodyn_init(void)
2899 {
2900         ftrace_enabled = 1;
2901         return 0;
2902 }
2903 device_initcall(ftrace_nodyn_init);
2904
2905 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
2906 static inline void ftrace_startup_enable(int command) { }
2907 /* Keep as macros so we do not need to define the commands */
2908 # define ftrace_startup(command)        do { } while (0)
2909 # define ftrace_shutdown(command)       do { } while (0)
2910 # define ftrace_startup_sysctl()        do { } while (0)
2911 # define ftrace_shutdown_sysctl()       do { } while (0)
2912 #endif /* CONFIG_DYNAMIC_FTRACE */
2913
2914 static ssize_t
2915 ftrace_pid_read(struct file *file, char __user *ubuf,
2916                        size_t cnt, loff_t *ppos)
2917 {
2918         char buf[64];
2919         int r;
2920
2921         if (ftrace_pid_trace == ftrace_swapper_pid)
2922                 r = sprintf(buf, "swapper tasks\n");
2923         else if (ftrace_pid_trace)
2924                 r = sprintf(buf, "%u\n", pid_vnr(ftrace_pid_trace));
2925         else
2926                 r = sprintf(buf, "no pid\n");
2927
2928         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2929 }
2930
2931 static void clear_ftrace_swapper(void)
2932 {
2933         struct task_struct *p;
2934         int cpu;
2935
2936         get_online_cpus();
2937         for_each_online_cpu(cpu) {
2938                 p = idle_task(cpu);
2939                 clear_tsk_trace_trace(p);
2940         }
2941         put_online_cpus();
2942 }
2943
2944 static void set_ftrace_swapper(void)
2945 {
2946         struct task_struct *p;
2947         int cpu;
2948
2949         get_online_cpus();
2950         for_each_online_cpu(cpu) {
2951                 p = idle_task(cpu);
2952                 set_tsk_trace_trace(p);
2953         }
2954         put_online_cpus();
2955 }
2956
2957 static void clear_ftrace_pid(struct pid *pid)
2958 {
2959         struct task_struct *p;
2960
2961         rcu_read_lock();
2962         do_each_pid_task(pid, PIDTYPE_PID, p) {
2963                 clear_tsk_trace_trace(p);
2964         } while_each_pid_task(pid, PIDTYPE_PID, p);
2965         rcu_read_unlock();
2966
2967         put_pid(pid);
2968 }
2969
2970 static void set_ftrace_pid(struct pid *pid)
2971 {
2972         struct task_struct *p;
2973
2974         rcu_read_lock();
2975         do_each_pid_task(pid, PIDTYPE_PID, p) {
2976                 set_tsk_trace_trace(p);
2977         } while_each_pid_task(pid, PIDTYPE_PID, p);
2978         rcu_read_unlock();
2979 }
2980
2981 static void clear_ftrace_pid_task(struct pid **pid)
2982 {
2983         if (*pid == ftrace_swapper_pid)
2984                 clear_ftrace_swapper();
2985         else
2986                 clear_ftrace_pid(*pid);
2987
2988         *pid = NULL;
2989 }
2990
2991 static void set_ftrace_pid_task(struct pid *pid)
2992 {
2993         if (pid == ftrace_swapper_pid)
2994                 set_ftrace_swapper();
2995         else
2996                 set_ftrace_pid(pid);
2997 }
2998
2999 static ssize_t
3000 ftrace_pid_write(struct file *filp, const char __user *ubuf,
3001                    size_t cnt, loff_t *ppos)
3002 {
3003         struct pid *pid;
3004         char buf[64];
3005         long val;
3006         int ret;
3007
3008         if (cnt >= sizeof(buf))
3009                 return -EINVAL;
3010
3011         if (copy_from_user(&buf, ubuf, cnt))
3012                 return -EFAULT;
3013
3014         buf[cnt] = 0;
3015
3016         ret = strict_strtol(buf, 10, &val);
3017         if (ret < 0)
3018                 return ret;
3019
3020         mutex_lock(&ftrace_lock);
3021         if (val < 0) {
3022                 /* disable pid tracing */
3023                 if (!ftrace_pid_trace)
3024                         goto out;
3025
3026                 clear_ftrace_pid_task(&ftrace_pid_trace);
3027
3028         } else {
3029                 /* swapper task is special */
3030                 if (!val) {
3031                         pid = ftrace_swapper_pid;
3032                         if (pid == ftrace_pid_trace)
3033                                 goto out;
3034                 } else {
3035                         pid = find_get_pid(val);
3036
3037                         if (pid == ftrace_pid_trace) {
3038                                 put_pid(pid);
3039                                 goto out;
3040                         }
3041                 }
3042
3043                 if (ftrace_pid_trace)
3044                         clear_ftrace_pid_task(&ftrace_pid_trace);
3045
3046                 if (!pid)
3047                         goto out;
3048
3049                 ftrace_pid_trace = pid;
3050
3051                 set_ftrace_pid_task(ftrace_pid_trace);
3052         }
3053
3054         /* update the function call */
3055         ftrace_update_pid_func();
3056         ftrace_startup_enable(0);
3057
3058  out:
3059         mutex_unlock(&ftrace_lock);
3060
3061         return cnt;
3062 }
3063
3064 static const struct file_operations ftrace_pid_fops = {
3065         .read = ftrace_pid_read,
3066         .write = ftrace_pid_write,
3067 };
3068
3069 static __init int ftrace_init_debugfs(void)
3070 {
3071         struct dentry *d_tracer;
3072
3073         d_tracer = tracing_init_dentry();
3074         if (!d_tracer)
3075                 return 0;
3076
3077         ftrace_init_dyn_debugfs(d_tracer);
3078
3079         trace_create_file("set_ftrace_pid", 0644, d_tracer,
3080                             NULL, &ftrace_pid_fops);
3081
3082         ftrace_profile_debugfs(d_tracer);
3083
3084         return 0;
3085 }
3086 fs_initcall(ftrace_init_debugfs);
3087
3088 /**
3089  * ftrace_kill - kill ftrace
3090  *
3091  * This function should be used by panic code. It stops ftrace
3092  * but in a not so nice way. If you need to simply kill ftrace
3093  * from a non-atomic section, use ftrace_kill.
3094  */
3095 void ftrace_kill(void)
3096 {
3097         ftrace_disabled = 1;
3098         ftrace_enabled = 0;
3099         clear_ftrace_function();
3100 }
3101
3102 /**
3103  * register_ftrace_function - register a function for profiling
3104  * @ops - ops structure that holds the function for profiling.
3105  *
3106  * Register a function to be called by all functions in the
3107  * kernel.
3108  *
3109  * Note: @ops->func and all the functions it calls must be labeled
3110  *       with "notrace", otherwise it will go into a
3111  *       recursive loop.
3112  */
3113 int register_ftrace_function(struct ftrace_ops *ops)
3114 {
3115         int ret;
3116
3117         if (unlikely(ftrace_disabled))
3118                 return -1;
3119
3120         mutex_lock(&ftrace_lock);
3121
3122         ret = __register_ftrace_function(ops);
3123         ftrace_startup(0);
3124
3125         mutex_unlock(&ftrace_lock);
3126         return ret;
3127 }
3128
3129 /**
3130  * unregister_ftrace_function - unregister a function for profiling.
3131  * @ops - ops structure that holds the function to unregister
3132  *
3133  * Unregister a function that was added to be called by ftrace profiling.
3134  */
3135 int unregister_ftrace_function(struct ftrace_ops *ops)
3136 {
3137         int ret;
3138
3139         mutex_lock(&ftrace_lock);
3140         ret = __unregister_ftrace_function(ops);
3141         ftrace_shutdown(0);
3142         mutex_unlock(&ftrace_lock);
3143
3144         return ret;
3145 }
3146
3147 int
3148 ftrace_enable_sysctl(struct ctl_table *table, int write,
3149                      struct file *file, void __user *buffer, size_t *lenp,
3150                      loff_t *ppos)
3151 {
3152         int ret;
3153
3154         if (unlikely(ftrace_disabled))
3155                 return -ENODEV;
3156
3157         mutex_lock(&ftrace_lock);
3158
3159         ret  = proc_dointvec(table, write, file, buffer, lenp, ppos);
3160
3161         if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
3162                 goto out;
3163
3164         last_ftrace_enabled = ftrace_enabled;
3165
3166         if (ftrace_enabled) {
3167
3168                 ftrace_startup_sysctl();
3169
3170                 /* we are starting ftrace again */
3171                 if (ftrace_list != &ftrace_list_end) {
3172                         if (ftrace_list->next == &ftrace_list_end)
3173                                 ftrace_trace_function = ftrace_list->func;
3174                         else
3175                                 ftrace_trace_function = ftrace_list_func;
3176                 }
3177
3178         } else {
3179                 /* stopping ftrace calls (just send to ftrace_stub) */
3180                 ftrace_trace_function = ftrace_stub;
3181
3182                 ftrace_shutdown_sysctl();
3183         }
3184
3185  out:
3186         mutex_unlock(&ftrace_lock);
3187         return ret;
3188 }
3189
3190 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3191
3192 static int ftrace_graph_active;
3193 static struct notifier_block ftrace_suspend_notifier;
3194
3195 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
3196 {
3197         return 0;
3198 }
3199
3200 /* The callbacks that hook a function */
3201 trace_func_graph_ret_t ftrace_graph_return =
3202                         (trace_func_graph_ret_t)ftrace_stub;
3203 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
3204
3205 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3206 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
3207 {
3208         int i;
3209         int ret = 0;
3210         unsigned long flags;
3211         int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
3212         struct task_struct *g, *t;
3213
3214         for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
3215                 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
3216                                         * sizeof(struct ftrace_ret_stack),
3217                                         GFP_KERNEL);
3218                 if (!ret_stack_list[i]) {
3219                         start = 0;
3220                         end = i;
3221                         ret = -ENOMEM;
3222                         goto free;
3223                 }
3224         }
3225
3226         read_lock_irqsave(&tasklist_lock, flags);
3227         do_each_thread(g, t) {
3228                 if (start == end) {
3229                         ret = -EAGAIN;
3230                         goto unlock;
3231                 }
3232
3233                 if (t->ret_stack == NULL) {
3234                         atomic_set(&t->tracing_graph_pause, 0);
3235                         atomic_set(&t->trace_overrun, 0);
3236                         t->curr_ret_stack = -1;
3237                         /* Make sure the tasks see the -1 first: */
3238                         smp_wmb();
3239                         t->ret_stack = ret_stack_list[start++];
3240                 }
3241         } while_each_thread(g, t);
3242
3243 unlock:
3244         read_unlock_irqrestore(&tasklist_lock, flags);
3245 free:
3246         for (i = start; i < end; i++)
3247                 kfree(ret_stack_list[i]);
3248         return ret;
3249 }
3250
3251 static void
3252 ftrace_graph_probe_sched_switch(struct rq *__rq, struct task_struct *prev,
3253                                 struct task_struct *next)
3254 {
3255         unsigned long long timestamp;
3256         int index;
3257
3258         /*
3259          * Does the user want to count the time a function was asleep.
3260          * If so, do not update the time stamps.
3261          */
3262         if (trace_flags & TRACE_ITER_SLEEP_TIME)
3263                 return;
3264
3265         timestamp = trace_clock_local();
3266
3267         prev->ftrace_timestamp = timestamp;
3268
3269         /* only process tasks that we timestamped */
3270         if (!next->ftrace_timestamp)
3271                 return;
3272
3273         /*
3274          * Update all the counters in next to make up for the
3275          * time next was sleeping.
3276          */
3277         timestamp -= next->ftrace_timestamp;
3278
3279         for (index = next->curr_ret_stack; index >= 0; index--)
3280                 next->ret_stack[index].calltime += timestamp;
3281 }
3282
3283 /* Allocate a return stack for each task */
3284 static int start_graph_tracing(void)
3285 {
3286         struct ftrace_ret_stack **ret_stack_list;
3287         int ret, cpu;
3288
3289         ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
3290                                 sizeof(struct ftrace_ret_stack *),
3291                                 GFP_KERNEL);
3292
3293         if (!ret_stack_list)
3294                 return -ENOMEM;
3295
3296         /* The cpu_boot init_task->ret_stack will never be freed */
3297         for_each_online_cpu(cpu) {
3298                 if (!idle_task(cpu)->ret_stack)
3299                         ftrace_graph_init_task(idle_task(cpu));
3300         }
3301
3302         do {
3303                 ret = alloc_retstack_tasklist(ret_stack_list);
3304         } while (ret == -EAGAIN);
3305
3306         if (!ret) {
3307                 ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch);
3308                 if (ret)
3309                         pr_info("ftrace_graph: Couldn't activate tracepoint"
3310                                 " probe to kernel_sched_switch\n");
3311         }
3312
3313         kfree(ret_stack_list);
3314         return ret;
3315 }
3316
3317 /*
3318  * Hibernation protection.
3319  * The state of the current task is too much unstable during
3320  * suspend/restore to disk. We want to protect against that.
3321  */
3322 static int
3323 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
3324                                                         void *unused)
3325 {
3326         switch (state) {
3327         case PM_HIBERNATION_PREPARE:
3328                 pause_graph_tracing();
3329                 break;
3330
3331         case PM_POST_HIBERNATION:
3332                 unpause_graph_tracing();
3333                 break;
3334         }
3335         return NOTIFY_DONE;
3336 }
3337
3338 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
3339                         trace_func_graph_ent_t entryfunc)
3340 {
3341         int ret = 0;
3342
3343         mutex_lock(&ftrace_lock);
3344
3345         /* we currently allow only one tracer registered at a time */
3346         if (ftrace_graph_active) {
3347                 ret = -EBUSY;
3348                 goto out;
3349         }
3350
3351         ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
3352         register_pm_notifier(&ftrace_suspend_notifier);
3353
3354         ftrace_graph_active++;
3355         ret = start_graph_tracing();
3356         if (ret) {
3357                 ftrace_graph_active--;
3358                 goto out;
3359         }
3360
3361         ftrace_graph_return = retfunc;
3362         ftrace_graph_entry = entryfunc;
3363
3364         ftrace_startup(FTRACE_START_FUNC_RET);
3365
3366 out:
3367         mutex_unlock(&ftrace_lock);
3368         return ret;
3369 }
3370
3371 void unregister_ftrace_graph(void)
3372 {
3373         mutex_lock(&ftrace_lock);
3374
3375         if (unlikely(!ftrace_graph_active))
3376                 goto out;
3377
3378         ftrace_graph_active--;
3379         unregister_trace_sched_switch(ftrace_graph_probe_sched_switch);
3380         ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
3381         ftrace_graph_entry = ftrace_graph_entry_stub;
3382         ftrace_shutdown(FTRACE_STOP_FUNC_RET);
3383         unregister_pm_notifier(&ftrace_suspend_notifier);
3384
3385  out:
3386         mutex_unlock(&ftrace_lock);
3387 }
3388
3389 /* Allocate a return stack for newly created task */
3390 void ftrace_graph_init_task(struct task_struct *t)
3391 {
3392         /* Make sure we do not use the parent ret_stack */
3393         t->ret_stack = NULL;
3394
3395         if (ftrace_graph_active) {
3396                 struct ftrace_ret_stack *ret_stack;
3397
3398                 ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
3399                                 * sizeof(struct ftrace_ret_stack),
3400                                 GFP_KERNEL);
3401                 if (!ret_stack)
3402                         return;
3403                 t->curr_ret_stack = -1;
3404                 atomic_set(&t->tracing_graph_pause, 0);
3405                 atomic_set(&t->trace_overrun, 0);
3406                 t->ftrace_timestamp = 0;
3407                 /* make curr_ret_stack visable before we add the ret_stack */
3408                 smp_wmb();
3409                 t->ret_stack = ret_stack;
3410         }
3411 }
3412
3413 void ftrace_graph_exit_task(struct task_struct *t)
3414 {
3415         struct ftrace_ret_stack *ret_stack = t->ret_stack;
3416
3417         t->ret_stack = NULL;
3418         /* NULL must become visible to IRQs before we free it: */
3419         barrier();
3420
3421         kfree(ret_stack);
3422 }
3423
3424 void ftrace_graph_stop(void)
3425 {
3426         ftrace_stop();
3427 }
3428 #endif
3429