SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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 <asm/ftrace.h>
  33
  34 #include "trace.h"
  35
  36 #define FTRACE_WARN_ON(cond)                    \
  37         do {                                    \
  38                 if (WARN_ON(cond))              \
  39                         ftrace_kill();          \
  40         } while (0)
  41
  42 #define FTRACE_WARN_ON_ONCE(cond)               \
  43         do {                                    \
  44                 if (WARN_ON_ONCE(cond))         \
  45                         ftrace_kill();          \
  46         } while (0)
  47
  48 /* hash bits for specific function selection */
  49 #define FTRACE_HASH_BITS 7
  50 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
  51
  52 /* ftrace_enabled is a method to turn ftrace on or off */
  53 int ftrace_enabled __read_mostly;
  54 static int last_ftrace_enabled;
  55
  56 /* Quick disabling of function tracer. */
  57 int function_trace_stop;
  58
  59 /*
  60  * ftrace_disabled is set when an anomaly is discovered.
  61  * ftrace_disabled is much stronger than ftrace_enabled.
  62  */
  63 static int ftrace_disabled __read_mostly;
  64
  65 static DEFINE_MUTEX(ftrace_lock);
  66
  67 static struct ftrace_ops ftrace_list_end __read_mostly =
  68 {
  69         .func = ftrace_stub,
  70 };
  71
  72 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
  73 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
  74 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
  75 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
  76
  77 static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
  78 {
  79         struct ftrace_ops *op = ftrace_list;
  80
  81         /* in case someone actually ports this to alpha! */
  82         read_barrier_depends();
  83
  84         while (op != &ftrace_list_end) {
  85                 /* silly alpha */
  86                 read_barrier_depends();
  87                 op->func(ip, parent_ip);
  88                 op = op->next;
  89         };
  90 }
  91
  92 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
  93 {
  94         if (!test_tsk_trace_trace(current))
  95                 return;
  96
  97         ftrace_pid_function(ip, parent_ip);
  98 }
  99
 100 static void set_ftrace_pid_function(ftrace_func_t func)
 101 {
 102         /* do not set ftrace_pid_function to itself! */
 103         if (func != ftrace_pid_func)
 104                 ftrace_pid_function = func;
 105 }
 106
 107 /**
 108  * clear_ftrace_function - reset the ftrace function
 109  *
 110  * This NULLs the ftrace function and in essence stops
 111  * tracing.  There may be lag
 112  */
 113 void clear_ftrace_function(void)
 114 {
 115         ftrace_trace_function = ftrace_stub;
 116         __ftrace_trace_function = ftrace_stub;
 117         ftrace_pid_function = ftrace_stub;
 118 }
 119
 120 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 121 /*
 122  * For those archs that do not test ftrace_trace_stop in their
 123  * mcount call site, we need to do it from C.
 124  */
 125 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
 126 {
 127         if (function_trace_stop)
 128                 return;
 129
 130         __ftrace_trace_function(ip, parent_ip);
 131 }
 132 #endif
 133
 134 static int __register_ftrace_function(struct ftrace_ops *ops)
 135 {
 136         ops->next = ftrace_list;
 137         /*
 138          * We are entering ops into the ftrace_list but another
 139          * CPU might be walking that list. We need to make sure
 140          * the ops->next pointer is valid before another CPU sees
 141          * the ops pointer included into the ftrace_list.
 142          */
 143         smp_wmb();
 144         ftrace_list = ops;
 145
 146         if (ftrace_enabled) {
 147                 ftrace_func_t func;
 148
 149                 if (ops->next == &ftrace_list_end)
 150                         func = ops->func;
 151                 else
 152                         func = ftrace_list_func;
 153
 154                 if (ftrace_pid_trace) {
 155                         set_ftrace_pid_function(func);
 156                         func = ftrace_pid_func;
 157                 }
 158
 159                 /*
 160                  * For one func, simply call it directly.
 161                  * For more than one func, call the chain.
 162                  */
 163 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 164                 ftrace_trace_function = func;
 165 #else
 166                 __ftrace_trace_function = func;
 167                 ftrace_trace_function = ftrace_test_stop_func;
 168 #endif
 169         }
 170
 171         return 0;
 172 }
 173
 174 static int __unregister_ftrace_function(struct ftrace_ops *ops)
 175 {
 176         struct ftrace_ops **p;
 177
 178         /*
 179          * If we are removing the last function, then simply point
 180          * to the ftrace_stub.
 181          */
 182         if (ftrace_list == ops && ops->next == &ftrace_list_end) {
 183                 ftrace_trace_function = ftrace_stub;
 184                 ftrace_list = &ftrace_list_end;
 185                 return 0;
 186         }
 187
 188         for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
 189                 if (*p == ops)
 190                         break;
 191
 192         if (*p != ops)
 193                 return -1;
 194
 195         *p = (*p)->next;
 196
 197         if (ftrace_enabled) {
 198                 /* If we only have one func left, then call that directly */
 199                 if (ftrace_list->next == &ftrace_list_end) {
 200                         ftrace_func_t func = ftrace_list->func;
 201
 202                         if (ftrace_pid_trace) {
 203                                 set_ftrace_pid_function(func);
 204                                 func = ftrace_pid_func;
 205                         }
 206 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 207                         ftrace_trace_function = func;
 208 #else
 209                         __ftrace_trace_function = func;
 210 #endif
 211                 }
 212         }
 213
 214         return 0;
 215 }
 216
 217 static void ftrace_update_pid_func(void)
 218 {
 219         ftrace_func_t func;
 220
 221         if (ftrace_trace_function == ftrace_stub)
 222                 return;
 223
 224         func = ftrace_trace_function;
 225
 226         if (ftrace_pid_trace) {
 227                 set_ftrace_pid_function(func);
 228                 func = ftrace_pid_func;
 229         } else {
 230                 if (func == ftrace_pid_func)
 231                         func = ftrace_pid_function;
 232         }
 233
 234 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 235         ftrace_trace_function = func;
 236 #else
 237         __ftrace_trace_function = func;
 238 #endif
 239 }
 240
 241 /* set when tracing only a pid */
 242 struct pid *ftrace_pid_trace;
 243 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
 244
 245 #ifdef CONFIG_DYNAMIC_FTRACE
 246
 247 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
 248 # error Dynamic ftrace depends on MCOUNT_RECORD
 249 #endif
 250
 251 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
 252
 253 struct ftrace_func_probe {
 254         struct hlist_node       node;
 255         struct ftrace_probe_ops *ops;
 256         unsigned long           flags;
 257         unsigned long           ip;
 258         void                    *data;
 259         struct rcu_head         rcu;
 260 };
 261
 262
 263 enum {
 264         FTRACE_ENABLE_CALLS             = (1 << 0),
 265         FTRACE_DISABLE_CALLS            = (1 << 1),
 266         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
 267         FTRACE_ENABLE_MCOUNT            = (1 << 3),
 268         FTRACE_DISABLE_MCOUNT           = (1 << 4),
 269         FTRACE_START_FUNC_RET           = (1 << 5),
 270         FTRACE_STOP_FUNC_RET            = (1 << 6),
 271 };
 272
 273 static int ftrace_filtered;
 274
 275 static LIST_HEAD(ftrace_new_addrs);
 276
 277 static DEFINE_MUTEX(ftrace_regex_lock);
 278
 279 struct ftrace_page {
 280         struct ftrace_page      *next;
 281         int                     index;
 282         struct dyn_ftrace       records[];
 283 };
 284
 285 #define ENTRIES_PER_PAGE \
 286   ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
 287
 288 /* estimate from running different kernels */
 289 #define NR_TO_INIT              10000
 290
 291 static struct ftrace_page       *ftrace_pages_start;
 292 static struct ftrace_page       *ftrace_pages;
 293
 294 static struct dyn_ftrace *ftrace_free_records;
 295
 296 /*
 297  * This is a double for. Do not use 'break' to break out of the loop,
 298  * you must use a goto.
 299  */
 300 #define do_for_each_ftrace_rec(pg, rec)                                 \
 301         for (pg = ftrace_pages_start; pg; pg = pg->next) {              \
 302                 int _____i;                                             \
 303                 for (_____i = 0; _____i < pg->index; _____i++) {        \
 304                         rec = &pg->records[_____i];
 305
 306 #define while_for_each_ftrace_rec()             \
 307                 }                               \
 308         }
 309
 310 #ifdef CONFIG_KPROBES
 311
 312 static int frozen_record_count;
 313
 314 static inline void freeze_record(struct dyn_ftrace *rec)
 315 {
 316         if (!(rec->flags & FTRACE_FL_FROZEN)) {
 317                 rec->flags |= FTRACE_FL_FROZEN;
 318                 frozen_record_count++;
 319         }
 320 }
 321
 322 static inline void unfreeze_record(struct dyn_ftrace *rec)
 323 {
 324         if (rec->flags & FTRACE_FL_FROZEN) {
 325                 rec->flags &= ~FTRACE_FL_FROZEN;
 326                 frozen_record_count--;
 327         }
 328 }
 329
 330 static inline int record_frozen(struct dyn_ftrace *rec)
 331 {
 332         return rec->flags & FTRACE_FL_FROZEN;
 333 }
 334 #else
 335 # define freeze_record(rec)                     ({ 0; })
 336 # define unfreeze_record(rec)                   ({ 0; })
 337 # define record_frozen(rec)                     ({ 0; })
 338 #endif /* CONFIG_KPROBES */
 339
 340 static void ftrace_free_rec(struct dyn_ftrace *rec)
 341 {
 342         rec->ip = (unsigned long)ftrace_free_records;
 343         ftrace_free_records = rec;
 344         rec->flags |= FTRACE_FL_FREE;
 345 }
 346
 347 void ftrace_release(void *start, unsigned long size)
 348 {
 349         struct dyn_ftrace *rec;
 350         struct ftrace_page *pg;
 351         unsigned long s = (unsigned long)start;
 352         unsigned long e = s + size;
 353
 354         if (ftrace_disabled || !start)
 355                 return;
 356
 357         mutex_lock(&ftrace_lock);
 358         do_for_each_ftrace_rec(pg, rec) {
 359                 if ((rec->ip >= s) && (rec->ip < e) &&
 360                     !(rec->flags & FTRACE_FL_FREE))
 361                         ftrace_free_rec(rec);
 362         } while_for_each_ftrace_rec();
 363         mutex_unlock(&ftrace_lock);
 364 }
 365
 366 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
 367 {
 368         struct dyn_ftrace *rec;
 369
 370         /* First check for freed records */
 371         if (ftrace_free_records) {
 372                 rec = ftrace_free_records;
 373
 374                 if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
 375                         FTRACE_WARN_ON_ONCE(1);
 376                         ftrace_free_records = NULL;
 377                         return NULL;
 378                 }
 379
 380                 ftrace_free_records = (void *)rec->ip;
 381                 memset(rec, 0, sizeof(*rec));
 382                 return rec;
 383         }
 384
 385         if (ftrace_pages->index == ENTRIES_PER_PAGE) {
 386                 if (!ftrace_pages->next) {
 387                         /* allocate another page */
 388                         ftrace_pages->next =
 389                                 (void *)get_zeroed_page(GFP_KERNEL);
 390                         if (!ftrace_pages->next)
 391                                 return NULL;
 392                 }
 393                 ftrace_pages = ftrace_pages->next;
 394         }
 395
 396         return &ftrace_pages->records[ftrace_pages->index++];
 397 }
 398
 399 static struct dyn_ftrace *
 400 ftrace_record_ip(unsigned long ip)
 401 {
 402         struct dyn_ftrace *rec;
 403
 404         if (ftrace_disabled)
 405                 return NULL;
 406
 407         rec = ftrace_alloc_dyn_node(ip);
 408         if (!rec)
 409                 return NULL;
 410
 411         rec->ip = ip;
 412
 413         list_add(&rec->list, &ftrace_new_addrs);
 414
 415         return rec;
 416 }
 417
 418 static void print_ip_ins(const char *fmt, unsigned char *p)
 419 {
 420         int i;
 421
 422         printk(KERN_CONT "%s", fmt);
 423
 424         for (i = 0; i < MCOUNT_INSN_SIZE; i++)
 425                 printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
 426 }
 427
 428 static void ftrace_bug(int failed, unsigned long ip)
 429 {
 430         switch (failed) {
 431         case -EFAULT:
 432                 FTRACE_WARN_ON_ONCE(1);
 433                 pr_info("ftrace faulted on modifying ");
 434                 print_ip_sym(ip);
 435                 break;
 436         case -EINVAL:
 437                 FTRACE_WARN_ON_ONCE(1);
 438                 pr_info("ftrace failed to modify ");
 439                 print_ip_sym(ip);
 440                 print_ip_ins(" actual: ", (unsigned char *)ip);
 441                 printk(KERN_CONT "\n");
 442                 break;
 443         case -EPERM:
 444                 FTRACE_WARN_ON_ONCE(1);
 445                 pr_info("ftrace faulted on writing ");
 446                 print_ip_sym(ip);
 447                 break;
 448         default:
 449                 FTRACE_WARN_ON_ONCE(1);
 450                 pr_info("ftrace faulted on unknown error ");
 451                 print_ip_sym(ip);
 452         }
 453 }
 454
 455
 456 static int
 457 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
 458 {
 459         unsigned long ftrace_addr;
 460         unsigned long ip, fl;
 461
 462         ftrace_addr = (unsigned long)FTRACE_ADDR;
 463
 464         ip = rec->ip;
 465
 466         /*
 467          * If this record is not to be traced and
 468          * it is not enabled then do nothing.
 469          *
 470          * If this record is not to be traced and
 471          * it is enabled then disable it.
 472          *
 473          */
 474         if (rec->flags & FTRACE_FL_NOTRACE) {
 475                 if (rec->flags & FTRACE_FL_ENABLED)
 476                         rec->flags &= ~FTRACE_FL_ENABLED;
 477                 else
 478                         return 0;
 479
 480         } else if (ftrace_filtered && enable) {
 481                 /*
 482                  * Filtering is on:
 483                  */
 484
 485                 fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED);
 486
 487                 /* Record is filtered and enabled, do nothing */
 488                 if (fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED))
 489                         return 0;
 490
 491                 /* Record is not filtered or enabled, do nothing */
 492                 if (!fl)
 493                         return 0;
 494
 495                 /* Record is not filtered but enabled, disable it */
 496                 if (fl == FTRACE_FL_ENABLED)
 497                         rec->flags &= ~FTRACE_FL_ENABLED;
 498                 else
 499                 /* Otherwise record is filtered but not enabled, enable it */
 500                         rec->flags |= FTRACE_FL_ENABLED;
 501         } else {
 502                 /* Disable or not filtered */
 503
 504                 if (enable) {
 505                         /* if record is enabled, do nothing */
 506                         if (rec->flags & FTRACE_FL_ENABLED)
 507                                 return 0;
 508
 509                         rec->flags |= FTRACE_FL_ENABLED;
 510
 511                 } else {
 512
 513                         /* if record is not enabled, do nothing */
 514                         if (!(rec->flags & FTRACE_FL_ENABLED))
 515                                 return 0;
 516
 517                         rec->flags &= ~FTRACE_FL_ENABLED;
 518                 }
 519         }
 520
 521         if (rec->flags & FTRACE_FL_ENABLED)
 522                 return ftrace_make_call(rec, ftrace_addr);
 523         else
 524                 return ftrace_make_nop(NULL, rec, ftrace_addr);
 525 }
 526
 527 static void ftrace_replace_code(int enable)
 528 {
 529         struct dyn_ftrace *rec;
 530         struct ftrace_page *pg;
 531         int failed;
 532
 533         do_for_each_ftrace_rec(pg, rec) {
 534                 /*
 535                  * Skip over free records, records that have
 536                  * failed and not converted.
 537                  */
 538                 if (rec->flags & FTRACE_FL_FREE ||
 539                     rec->flags & FTRACE_FL_FAILED ||
 540                     rec->flags & FTRACE_FL_CONVERTED)
 541                         continue;
 542
 543                 /* ignore updates to this record's mcount site */
 544                 if (get_kprobe((void *)rec->ip)) {
 545                         freeze_record(rec);
 546                         continue;
 547                 } else {
 548                         unfreeze_record(rec);
 549                 }
 550
 551                 failed = __ftrace_replace_code(rec, enable);
 552                 if (failed) {
 553                         rec->flags |= FTRACE_FL_FAILED;
 554                         if ((system_state == SYSTEM_BOOTING) ||
 555                             !core_kernel_text(rec->ip)) {
 556                                 ftrace_free_rec(rec);
 557                                 } else {
 558                                 ftrace_bug(failed, rec->ip);
 559                                         /* Stop processing */
 560                                         return;
 561                                 }
 562                 }
 563         } while_for_each_ftrace_rec();
 564 }
 565
 566 static int
 567 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
 568 {
 569         unsigned long ip;
 570         int ret;
 571
 572         ip = rec->ip;
 573
 574         ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
 575         if (ret) {
 576                 ftrace_bug(ret, ip);
 577                 rec->flags |= FTRACE_FL_FAILED;
 578                 return 0;
 579         }
 580         return 1;
 581 }
 582
 583 /*
 584  * archs can override this function if they must do something
 585  * before the modifying code is performed.
 586  */
 587 int __weak ftrace_arch_code_modify_prepare(void)
 588 {
 589         return 0;
 590 }
 591
 592 /*
 593  * archs can override this function if they must do something
 594  * after the modifying code is performed.
 595  */
 596 int __weak ftrace_arch_code_modify_post_process(void)
 597 {
 598         return 0;
 599 }
 600
 601 static int __ftrace_modify_code(void *data)
 602 {
 603         int *command = data;
 604
 605         if (*command & FTRACE_ENABLE_CALLS)
 606                 ftrace_replace_code(1);
 607         else if (*command & FTRACE_DISABLE_CALLS)
 608                 ftrace_replace_code(0);
 609
 610         if (*command & FTRACE_UPDATE_TRACE_FUNC)
 611                 ftrace_update_ftrace_func(ftrace_trace_function);
 612
 613         if (*command & FTRACE_START_FUNC_RET)
 614                 ftrace_enable_ftrace_graph_caller();
 615         else if (*command & FTRACE_STOP_FUNC_RET)
 616                 ftrace_disable_ftrace_graph_caller();
 617
 618         return 0;
 619 }
 620
 621 static void ftrace_run_update_code(int command)
 622 {
 623         int ret;
 624
 625         ret = ftrace_arch_code_modify_prepare();
 626         FTRACE_WARN_ON(ret);
 627         if (ret)
 628                 return;
 629
 630         stop_machine(__ftrace_modify_code, &command, NULL);
 631
 632         ret = ftrace_arch_code_modify_post_process();
 633         FTRACE_WARN_ON(ret);
 634 }
 635
 636 static ftrace_func_t saved_ftrace_func;
 637 static int ftrace_start_up;
 638
 639 static void ftrace_startup_enable(int command)
 640 {
 641         if (saved_ftrace_func != ftrace_trace_function) {
 642                 saved_ftrace_func = ftrace_trace_function;
 643                 command |= FTRACE_UPDATE_TRACE_FUNC;
 644         }
 645
 646         if (!command || !ftrace_enabled)
 647                 return;
 648
 649         ftrace_run_update_code(command);
 650 }
 651
 652 static void ftrace_startup(int command)
 653 {
 654         if (unlikely(ftrace_disabled))
 655                 return;
 656
 657         ftrace_start_up++;
 658         command |= FTRACE_ENABLE_CALLS;
 659
 660         ftrace_startup_enable(command);
 661 }
 662
 663 static void ftrace_shutdown(int command)
 664 {
 665         if (unlikely(ftrace_disabled))
 666                 return;
 667
 668         ftrace_start_up--;
 669         if (!ftrace_start_up)
 670                 command |= FTRACE_DISABLE_CALLS;
 671
 672         if (saved_ftrace_func != ftrace_trace_function) {
 673                 saved_ftrace_func = ftrace_trace_function;
 674                 command |= FTRACE_UPDATE_TRACE_FUNC;
 675         }
 676
 677         if (!command || !ftrace_enabled)
 678                 return;
 679
 680         ftrace_run_update_code(command);
 681 }
 682
 683 static void ftrace_startup_sysctl(void)
 684 {
 685         int command = FTRACE_ENABLE_MCOUNT;
 686
 687         if (unlikely(ftrace_disabled))
 688                 return;
 689
 690         /* Force update next time */
 691         saved_ftrace_func = NULL;
 692         /* ftrace_start_up is true if we want ftrace running */
 693         if (ftrace_start_up)
 694                 command |= FTRACE_ENABLE_CALLS;
 695
 696         ftrace_run_update_code(command);
 697 }
 698
 699 static void ftrace_shutdown_sysctl(void)
 700 {
 701         int command = FTRACE_DISABLE_MCOUNT;
 702
 703         if (unlikely(ftrace_disabled))
 704                 return;
 705
 706         /* ftrace_start_up is true if ftrace is running */
 707         if (ftrace_start_up)
 708                 command |= FTRACE_DISABLE_CALLS;
 709
 710         ftrace_run_update_code(command);
 711 }
 712
 713 static cycle_t          ftrace_update_time;
 714 static unsigned long    ftrace_update_cnt;
 715 unsigned long           ftrace_update_tot_cnt;
 716
 717 static int ftrace_update_code(struct module *mod)
 718 {
 719         struct dyn_ftrace *p, *t;
 720         cycle_t start, stop;
 721
 722         start = ftrace_now(raw_smp_processor_id());
 723         ftrace_update_cnt = 0;
 724
 725         list_for_each_entry_safe(p, t, &ftrace_new_addrs, list) {
 726
 727                 /* If something went wrong, bail without enabling anything */
 728                 if (unlikely(ftrace_disabled))
 729                         return -1;
 730
 731                 list_del_init(&p->list);
 732
 733                 /* convert record (i.e, patch mcount-call with NOP) */
 734                 if (ftrace_code_disable(mod, p)) {
 735                         p->flags |= FTRACE_FL_CONVERTED;
 736                         ftrace_update_cnt++;
 737                 } else
 738                         ftrace_free_rec(p);
 739         }
 740
 741         stop = ftrace_now(raw_smp_processor_id());
 742         ftrace_update_time = stop - start;
 743         ftrace_update_tot_cnt += ftrace_update_cnt;
 744
 745         return 0;
 746 }
 747
 748 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
 749 {
 750         struct ftrace_page *pg;
 751         int cnt;
 752         int i;
 753
 754         /* allocate a few pages */
 755         ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
 756         if (!ftrace_pages_start)
 757                 return -1;
 758
 759         /*
 760          * Allocate a few more pages.
 761          *
 762          * TODO: have some parser search vmlinux before
 763          *   final linking to find all calls to ftrace.
 764          *   Then we can:
 765          *    a) know how many pages to allocate.
 766          *     and/or
 767          *    b) set up the table then.
 768          *
 769          *  The dynamic code is still necessary for
 770          *  modules.
 771          */
 772
 773         pg = ftrace_pages = ftrace_pages_start;
 774
 775         cnt = num_to_init / ENTRIES_PER_PAGE;
 776         pr_info("ftrace: allocating %ld entries in %d pages\n",
 777                 num_to_init, cnt + 1);
 778
 779         for (i = 0; i < cnt; i++) {
 780                 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
 781
 782                 /* If we fail, we'll try later anyway */
 783                 if (!pg->next)
 784                         break;
 785
 786                 pg = pg->next;
 787         }
 788
 789         return 0;
 790 }
 791
 792 enum {
 793         FTRACE_ITER_FILTER      = (1 << 0),
 794         FTRACE_ITER_CONT        = (1 << 1),
 795         FTRACE_ITER_NOTRACE     = (1 << 2),
 796         FTRACE_ITER_FAILURES    = (1 << 3),
 797         FTRACE_ITER_PRINTALL    = (1 << 4),
 798         FTRACE_ITER_HASH        = (1 << 5),
 799 };
 800
 801 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
 802
 803 struct ftrace_iterator {
 804         struct ftrace_page      *pg;
 805         int                     hidx;
 806         int                     idx;
 807         unsigned                flags;
 808         unsigned char           buffer[FTRACE_BUFF_MAX+1];
 809         unsigned                buffer_idx;
 810         unsigned                filtered;
 811 };
 812
 813 static void *
 814 t_hash_next(struct seq_file *m, void *v, loff_t *pos)
 815 {
 816         struct ftrace_iterator *iter = m->private;
 817         struct hlist_node *hnd = v;
 818         struct hlist_head *hhd;
 819
 820         WARN_ON(!(iter->flags & FTRACE_ITER_HASH));
 821
 822         (*pos)++;
 823
 824  retry:
 825         if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
 826                 return NULL;
 827
 828         hhd = &ftrace_func_hash[iter->hidx];
 829
 830         if (hlist_empty(hhd)) {
 831                 iter->hidx++;
 832                 hnd = NULL;
 833                 goto retry;
 834         }
 835
 836         if (!hnd)
 837                 hnd = hhd->first;
 838         else {
 839                 hnd = hnd->next;
 840                 if (!hnd) {
 841                         iter->hidx++;
 842                         goto retry;
 843                 }
 844         }
 845
 846         return hnd;
 847 }
 848
 849 static void *t_hash_start(struct seq_file *m, loff_t *pos)
 850 {
 851         struct ftrace_iterator *iter = m->private;
 852         void *p = NULL;
 853
 854         iter->flags |= FTRACE_ITER_HASH;
 855
 856         return t_hash_next(m, p, pos);
 857 }
 858
 859 static int t_hash_show(struct seq_file *m, void *v)
 860 {
 861         struct ftrace_func_probe *rec;
 862         struct hlist_node *hnd = v;
 863         char str[KSYM_SYMBOL_LEN];
 864
 865         rec = hlist_entry(hnd, struct ftrace_func_probe, node);
 866
 867         if (rec->ops->print)
 868                 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
 869
 870         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 871         seq_printf(m, "%s:", str);
 872
 873         kallsyms_lookup((unsigned long)rec->ops->func, NULL, NULL, NULL, str);
 874         seq_printf(m, "%s", str);
 875
 876         if (rec->data)
 877                 seq_printf(m, ":%p", rec->data);
 878         seq_putc(m, '\n');
 879
 880         return 0;
 881 }
 882
 883 static void *
 884 t_next(struct seq_file *m, void *v, loff_t *pos)
 885 {
 886         struct ftrace_iterator *iter = m->private;
 887         struct dyn_ftrace *rec = NULL;
 888
 889         if (iter->flags & FTRACE_ITER_HASH)
 890                 return t_hash_next(m, v, pos);
 891
 892         (*pos)++;
 893
 894         if (iter->flags & FTRACE_ITER_PRINTALL)
 895                 return NULL;
 896
 897  retry:
 898         if (iter->idx >= iter->pg->index) {
 899                 if (iter->pg->next) {
 900                         iter->pg = iter->pg->next;
 901                         iter->idx = 0;
 902                         goto retry;
 903                 } else {
 904                         iter->idx = -1;
 905                 }
 906         } else {
 907                 rec = &iter->pg->records[iter->idx++];
 908                 if ((rec->flags & FTRACE_FL_FREE) ||
 909
 910                     (!(iter->flags & FTRACE_ITER_FAILURES) &&
 911                      (rec->flags & FTRACE_FL_FAILED)) ||
 912
 913                     ((iter->flags & FTRACE_ITER_FAILURES) &&
 914                      !(rec->flags & FTRACE_FL_FAILED)) ||
 915
 916                     ((iter->flags & FTRACE_ITER_FILTER) &&
 917                      !(rec->flags & FTRACE_FL_FILTER)) ||
 918
 919                     ((iter->flags & FTRACE_ITER_NOTRACE) &&
 920                      !(rec->flags & FTRACE_FL_NOTRACE))) {
 921                         rec = NULL;
 922                         goto retry;
 923                 }
 924         }
 925
 926         return rec;
 927 }
 928
 929 static void *t_start(struct seq_file *m, loff_t *pos)
 930 {
 931         struct ftrace_iterator *iter = m->private;
 932         void *p = NULL;
 933
 934         mutex_lock(&ftrace_lock);
 935         /*
 936          * For set_ftrace_filter reading, if we have the filter
 937          * off, we can short cut and just print out that all
 938          * functions are enabled.
 939          */
 940         if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) {
 941                 if (*pos > 0)
 942                         return t_hash_start(m, pos);
 943                 iter->flags |= FTRACE_ITER_PRINTALL;
 944                 (*pos)++;
 945                 return iter;
 946         }
 947
 948         if (iter->flags & FTRACE_ITER_HASH)
 949                 return t_hash_start(m, pos);
 950
 951         if (*pos > 0) {
 952                 if (iter->idx < 0)
 953                         return p;
 954                 (*pos)--;
 955                 iter->idx--;
 956         }
 957
 958         p = t_next(m, p, pos);
 959
 960         if (!p)
 961                 return t_hash_start(m, pos);
 962
 963         return p;
 964 }
 965
 966 static void t_stop(struct seq_file *m, void *p)
 967 {
 968         mutex_unlock(&ftrace_lock);
 969 }
 970
 971 static int t_show(struct seq_file *m, void *v)
 972 {
 973         struct ftrace_iterator *iter = m->private;
 974         struct dyn_ftrace *rec = v;
 975         char str[KSYM_SYMBOL_LEN];
 976
 977         if (iter->flags & FTRACE_ITER_HASH)
 978                 return t_hash_show(m, v);
 979
 980         if (iter->flags & FTRACE_ITER_PRINTALL) {
 981                 seq_printf(m, "#### all functions enabled ####\n");
 982                 return 0;
 983         }
 984
 985         if (!rec)
 986                 return 0;
 987
 988         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 989
 990         seq_printf(m, "%s\n", str);
 991
 992         return 0;
 993 }
 994
 995 static struct seq_operations show_ftrace_seq_ops = {
 996         .start = t_start,
 997         .next = t_next,
 998         .stop = t_stop,
 999         .show = t_show,
1000 };
1001
1002 static int
1003 ftrace_avail_open(struct inode *inode, struct file *file)
1004 {
1005         struct ftrace_iterator *iter;
1006         int ret;
1007
1008         if (unlikely(ftrace_disabled))
1009                 return -ENODEV;
1010
1011         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1012         if (!iter)
1013                 return -ENOMEM;
1014
1015         iter->pg = ftrace_pages_start;
1016
1017         ret = seq_open(file, &show_ftrace_seq_ops);
1018         if (!ret) {
1019                 struct seq_file *m = file->private_data;
1020
1021                 m->private = iter;
1022         } else {
1023                 kfree(iter);
1024         }
1025
1026         return ret;
1027 }
1028
1029 int ftrace_avail_release(struct inode *inode, struct file *file)
1030 {
1031         struct seq_file *m = (struct seq_file *)file->private_data;
1032         struct ftrace_iterator *iter = m->private;
1033
1034         seq_release(inode, file);
1035         kfree(iter);
1036
1037         return 0;
1038 }
1039
1040 static int
1041 ftrace_failures_open(struct inode *inode, struct file *file)
1042 {
1043         int ret;
1044         struct seq_file *m;
1045         struct ftrace_iterator *iter;
1046
1047         ret = ftrace_avail_open(inode, file);
1048         if (!ret) {
1049                 m = (struct seq_file *)file->private_data;
1050                 iter = (struct ftrace_iterator *)m->private;
1051                 iter->flags = FTRACE_ITER_FAILURES;
1052         }
1053
1054         return ret;
1055 }
1056
1057
1058 static void ftrace_filter_reset(int enable)
1059 {
1060         struct ftrace_page *pg;
1061         struct dyn_ftrace *rec;
1062         unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1063
1064         mutex_lock(&ftrace_lock);
1065         if (enable)
1066                 ftrace_filtered = 0;
1067         do_for_each_ftrace_rec(pg, rec) {
1068                 if (rec->flags & FTRACE_FL_FAILED)
1069                         continue;
1070                 rec->flags &= ~type;
1071         } while_for_each_ftrace_rec();
1072         mutex_unlock(&ftrace_lock);
1073 }
1074
1075 static int
1076 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
1077 {
1078         struct ftrace_iterator *iter;
1079         int ret = 0;
1080
1081         if (unlikely(ftrace_disabled))
1082                 return -ENODEV;
1083
1084         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1085         if (!iter)
1086                 return -ENOMEM;
1087
1088         mutex_lock(&ftrace_regex_lock);
1089         if ((file->f_mode & FMODE_WRITE) &&
1090             !(file->f_flags & O_APPEND))
1091                 ftrace_filter_reset(enable);
1092
1093         if (file->f_mode & FMODE_READ) {
1094                 iter->pg = ftrace_pages_start;
1095                 iter->flags = enable ? FTRACE_ITER_FILTER :
1096                         FTRACE_ITER_NOTRACE;
1097
1098                 ret = seq_open(file, &show_ftrace_seq_ops);
1099                 if (!ret) {
1100                         struct seq_file *m = file->private_data;
1101                         m->private = iter;
1102                 } else
1103                         kfree(iter);
1104         } else
1105                 file->private_data = iter;
1106         mutex_unlock(&ftrace_regex_lock);
1107
1108         return ret;
1109 }
1110
1111 static int
1112 ftrace_filter_open(struct inode *inode, struct file *file)
1113 {
1114         return ftrace_regex_open(inode, file, 1);
1115 }
1116
1117 static int
1118 ftrace_notrace_open(struct inode *inode, struct file *file)
1119 {
1120         return ftrace_regex_open(inode, file, 0);
1121 }
1122
1123 static loff_t
1124 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
1125 {
1126         loff_t ret;
1127
1128         if (file->f_mode & FMODE_READ)
1129                 ret = seq_lseek(file, offset, origin);
1130         else
1131                 file->f_pos = ret = 1;
1132
1133         return ret;
1134 }
1135
1136 enum {
1137         MATCH_FULL,
1138         MATCH_FRONT_ONLY,
1139         MATCH_MIDDLE_ONLY,
1140         MATCH_END_ONLY,
1141 };
1142
1143 /*
1144  * (static function - no need for kernel doc)
1145  *
1146  * Pass in a buffer containing a glob and this function will
1147  * set search to point to the search part of the buffer and
1148  * return the type of search it is (see enum above).
1149  * This does modify buff.
1150  *
1151  * Returns enum type.
1152  *  search returns the pointer to use for comparison.
1153  *  not returns 1 if buff started with a '!'
1154  *     0 otherwise.
1155  */
1156 static int
1157 ftrace_setup_glob(char *buff, int len, char **search, int *not)
1158 {
1159         int type = MATCH_FULL;
1160         int i;
1161
1162         if (buff[0] == '!') {
1163                 *not = 1;
1164                 buff++;
1165                 len--;
1166         } else
1167                 *not = 0;
1168
1169         *search = buff;
1170
1171         for (i = 0; i < len; i++) {
1172                 if (buff[i] == '*') {
1173                         if (!i) {
1174                                 *search = buff + 1;
1175                                 type = MATCH_END_ONLY;
1176                         } else {
1177                                 if (type == MATCH_END_ONLY)
1178                                         type = MATCH_MIDDLE_ONLY;
1179                                 else
1180                                         type = MATCH_FRONT_ONLY;
1181                                 buff[i] = 0;
1182                                 break;
1183                         }
1184                 }
1185         }
1186
1187         return type;
1188 }
1189
1190 static int ftrace_match(char *str, char *regex, int len, int type)
1191 {
1192         int matched = 0;
1193         char *ptr;
1194
1195         switch (type) {
1196         case MATCH_FULL:
1197                 if (strcmp(str, regex) == 0)
1198                         matched = 1;
1199                 break;
1200         case MATCH_FRONT_ONLY:
1201                 if (strncmp(str, regex, len) == 0)
1202                         matched = 1;
1203                 break;
1204         case MATCH_MIDDLE_ONLY:
1205                 if (strstr(str, regex))
1206                         matched = 1;
1207                 break;
1208         case MATCH_END_ONLY:
1209                 ptr = strstr(str, regex);
1210                 if (ptr && (ptr[len] == 0))
1211                         matched = 1;
1212                 break;
1213         }
1214
1215         return matched;
1216 }
1217
1218 static int
1219 ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
1220 {
1221         char str[KSYM_SYMBOL_LEN];
1222
1223         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
1224         return ftrace_match(str, regex, len, type);
1225 }
1226
1227 static void ftrace_match_records(char *buff, int len, int enable)
1228 {
1229         unsigned int search_len;
1230         struct ftrace_page *pg;
1231         struct dyn_ftrace *rec;
1232         unsigned long flag;
1233         char *search;
1234         int type;
1235         int not;
1236
1237         flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1238         type = ftrace_setup_glob(buff, len, &search, &not);
1239
1240         search_len = strlen(search);
1241
1242         mutex_lock(&ftrace_lock);
1243         do_for_each_ftrace_rec(pg, rec) {
1244
1245                 if (rec->flags & FTRACE_FL_FAILED)
1246                         continue;
1247
1248                 if (ftrace_match_record(rec, search, search_len, type)) {
1249                         if (not)
1250                                 rec->flags &= ~flag;
1251                         else
1252                                 rec->flags |= flag;
1253                 }
1254                 /*
1255                  * Only enable filtering if we have a function that
1256                  * is filtered on.
1257                  */
1258                 if (enable && (rec->flags & FTRACE_FL_FILTER))
1259                         ftrace_filtered = 1;
1260         } while_for_each_ftrace_rec();
1261         mutex_unlock(&ftrace_lock);
1262 }
1263
1264 static int
1265 ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
1266                            char *regex, int len, int type)
1267 {
1268         char str[KSYM_SYMBOL_LEN];
1269         char *modname;
1270
1271         kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
1272
1273         if (!modname || strcmp(modname, mod))
1274                 return 0;
1275
1276         /* blank search means to match all funcs in the mod */
1277         if (len)
1278                 return ftrace_match(str, regex, len, type);
1279         else
1280                 return 1;
1281 }
1282
1283 static void ftrace_match_module_records(char *buff, char *mod, int enable)
1284 {
1285         unsigned search_len = 0;
1286         struct ftrace_page *pg;
1287         struct dyn_ftrace *rec;
1288         int type = MATCH_FULL;
1289         char *search = buff;
1290         unsigned long flag;
1291         int not = 0;
1292
1293         flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
1294
1295         /* blank or '*' mean the same */
1296         if (strcmp(buff, "*") == 0)
1297                 buff[0] = 0;
1298
1299         /* handle the case of 'dont filter this module' */
1300         if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
1301                 buff[0] = 0;
1302                 not = 1;
1303         }
1304
1305         if (strlen(buff)) {
1306                 type = ftrace_setup_glob(buff, strlen(buff), &search, &not);
1307                 search_len = strlen(search);
1308         }
1309
1310         mutex_lock(&ftrace_lock);
1311         do_for_each_ftrace_rec(pg, rec) {
1312
1313                 if (rec->flags & FTRACE_FL_FAILED)
1314                         continue;
1315
1316                 if (ftrace_match_module_record(rec, mod,
1317                                                search, search_len, type)) {
1318                         if (not)
1319                                 rec->flags &= ~flag;
1320                         else
1321                                 rec->flags |= flag;
1322                 }
1323                 if (enable && (rec->flags & FTRACE_FL_FILTER))
1324                         ftrace_filtered = 1;
1325
1326         } while_for_each_ftrace_rec();
1327         mutex_unlock(&ftrace_lock);
1328 }
1329
1330 /*
1331  * We register the module command as a template to show others how
1332  * to register the a command as well.
1333  */
1334
1335 static int
1336 ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
1337 {
1338         char *mod;
1339
1340         /*
1341          * cmd == 'mod' because we only registered this func
1342          * for the 'mod' ftrace_func_command.
1343          * But if you register one func with multiple commands,
1344          * you can tell which command was used by the cmd
1345          * parameter.
1346          */
1347
1348         /* we must have a module name */
1349         if (!param)
1350                 return -EINVAL;
1351
1352         mod = strsep(&param, ":");
1353         if (!strlen(mod))
1354                 return -EINVAL;
1355
1356         ftrace_match_module_records(func, mod, enable);
1357         return 0;
1358 }
1359
1360 static struct ftrace_func_command ftrace_mod_cmd = {
1361         .name                   = "mod",
1362         .func                   = ftrace_mod_callback,
1363 };
1364
1365 static int __init ftrace_mod_cmd_init(void)
1366 {
1367         return register_ftrace_command(&ftrace_mod_cmd);
1368 }
1369 device_initcall(ftrace_mod_cmd_init);
1370
1371 static void
1372 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
1373 {
1374         struct ftrace_func_probe *entry;
1375         struct hlist_head *hhd;
1376         struct hlist_node *n;
1377         unsigned long key;
1378         int resched;
1379
1380         key = hash_long(ip, FTRACE_HASH_BITS);
1381
1382         hhd = &ftrace_func_hash[key];
1383
1384         if (hlist_empty(hhd))
1385                 return;
1386
1387         /*
1388          * Disable preemption for these calls to prevent a RCU grace
1389          * period. This syncs the hash iteration and freeing of items
1390          * on the hash. rcu_read_lock is too dangerous here.
1391          */
1392         resched = ftrace_preempt_disable();
1393         hlist_for_each_entry_rcu(entry, n, hhd, node) {
1394                 if (entry->ip == ip)
1395                         entry->ops->func(ip, parent_ip, &entry->data);
1396         }
1397         ftrace_preempt_enable(resched);
1398 }
1399
1400 static struct ftrace_ops trace_probe_ops __read_mostly =
1401 {
1402         .func = function_trace_probe_call,
1403 };
1404
1405 static int ftrace_probe_registered;
1406
1407 static void __enable_ftrace_function_probe(void)
1408 {
1409         int i;
1410
1411         if (ftrace_probe_registered)
1412                 return;
1413
1414         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1415                 struct hlist_head *hhd = &ftrace_func_hash[i];
1416                 if (hhd->first)
1417                         break;
1418         }
1419         /* Nothing registered? */
1420         if (i == FTRACE_FUNC_HASHSIZE)
1421                 return;
1422
1423         __register_ftrace_function(&trace_probe_ops);
1424         ftrace_startup(0);
1425         ftrace_probe_registered = 1;
1426 }
1427
1428 static void __disable_ftrace_function_probe(void)
1429 {
1430         int i;
1431
1432         if (!ftrace_probe_registered)
1433                 return;
1434
1435         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1436                 struct hlist_head *hhd = &ftrace_func_hash[i];
1437                 if (hhd->first)
1438                         return;
1439         }
1440
1441         /* no more funcs left */
1442         __unregister_ftrace_function(&trace_probe_ops);
1443         ftrace_shutdown(0);
1444         ftrace_probe_registered = 0;
1445 }
1446
1447
1448 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
1449 {
1450         struct ftrace_func_probe *entry =
1451                 container_of(rhp, struct ftrace_func_probe, rcu);
1452
1453         if (entry->ops->free)
1454                 entry->ops->free(&entry->data);
1455         kfree(entry);
1456 }
1457
1458
1459 int
1460 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
1461                               void *data)
1462 {
1463         struct ftrace_func_probe *entry;
1464         struct ftrace_page *pg;
1465         struct dyn_ftrace *rec;
1466         int type, len, not;
1467         unsigned long key;
1468         int count = 0;
1469         char *search;
1470
1471         type = ftrace_setup_glob(glob, strlen(glob), &search, &not);
1472         len = strlen(search);
1473
1474         /* we do not support '!' for function probes */
1475         if (WARN_ON(not))
1476                 return -EINVAL;
1477
1478         mutex_lock(&ftrace_lock);
1479         do_for_each_ftrace_rec(pg, rec) {
1480
1481                 if (rec->flags & FTRACE_FL_FAILED)
1482                         continue;
1483
1484                 if (!ftrace_match_record(rec, search, len, type))
1485                         continue;
1486
1487                 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1488                 if (!entry) {
1489                         /* If we did not process any, then return error */
1490                         if (!count)
1491                                 count = -ENOMEM;
1492                         goto out_unlock;
1493                 }
1494
1495                 count++;
1496
1497                 entry->data = data;
1498
1499                 /*
1500                  * The caller might want to do something special
1501                  * for each function we find. We call the callback
1502                  * to give the caller an opportunity to do so.
1503                  */
1504                 if (ops->callback) {
1505                         if (ops->callback(rec->ip, &entry->data) < 0) {
1506                                 /* caller does not like this func */
1507                                 kfree(entry);
1508                                 continue;
1509                         }
1510                 }
1511
1512                 entry->ops = ops;
1513                 entry->ip = rec->ip;
1514
1515                 key = hash_long(entry->ip, FTRACE_HASH_BITS);
1516                 hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
1517
1518         } while_for_each_ftrace_rec();
1519         __enable_ftrace_function_probe();
1520
1521  out_unlock:
1522         mutex_unlock(&ftrace_lock);
1523
1524         return count;
1525 }
1526
1527 enum {
1528         PROBE_TEST_FUNC         = 1,
1529         PROBE_TEST_DATA         = 2
1530 };
1531
1532 static void
1533 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
1534                                   void *data, int flags)
1535 {
1536         struct ftrace_func_probe *entry;
1537         struct hlist_node *n, *tmp;
1538         char str[KSYM_SYMBOL_LEN];
1539         int type = MATCH_FULL;
1540         int i, len = 0;
1541         char *search;
1542
1543         if (glob && (strcmp(glob, "*") || !strlen(glob)))
1544                 glob = NULL;
1545         else {
1546                 int not;
1547
1548                 type = ftrace_setup_glob(glob, strlen(glob), &search, &not);
1549                 len = strlen(search);
1550
1551                 /* we do not support '!' for function probes */
1552                 if (WARN_ON(not))
1553                         return;
1554         }
1555
1556         mutex_lock(&ftrace_lock);
1557         for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
1558                 struct hlist_head *hhd = &ftrace_func_hash[i];
1559
1560                 hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
1561
1562                         /* break up if statements for readability */
1563                         if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
1564                                 continue;
1565
1566                         if ((flags & PROBE_TEST_DATA) && entry->data != data)
1567                                 continue;
1568
1569                         /* do this last, since it is the most expensive */
1570                         if (glob) {
1571                                 kallsyms_lookup(entry->ip, NULL, NULL,
1572                                                 NULL, str);
1573                                 if (!ftrace_match(str, glob, len, type))
1574                                         continue;
1575                         }
1576
1577                         hlist_del(&entry->node);
1578                         call_rcu(&entry->rcu, ftrace_free_entry_rcu);
1579                 }
1580         }
1581         __disable_ftrace_function_probe();
1582         mutex_unlock(&ftrace_lock);
1583 }
1584
1585 void
1586 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
1587                                 void *data)
1588 {
1589         __unregister_ftrace_function_probe(glob, ops, data,
1590                                           PROBE_TEST_FUNC | PROBE_TEST_DATA);
1591 }
1592
1593 void
1594 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
1595 {
1596         __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
1597 }
1598
1599 void unregister_ftrace_function_probe_all(char *glob)
1600 {
1601         __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
1602 }
1603
1604 static LIST_HEAD(ftrace_commands);
1605 static DEFINE_MUTEX(ftrace_cmd_mutex);
1606
1607 int register_ftrace_command(struct ftrace_func_command *cmd)
1608 {
1609         struct ftrace_func_command *p;
1610         int ret = 0;
1611
1612         mutex_lock(&ftrace_cmd_mutex);
1613         list_for_each_entry(p, &ftrace_commands, list) {
1614                 if (strcmp(cmd->name, p->name) == 0) {
1615                         ret = -EBUSY;
1616                         goto out_unlock;
1617                 }
1618         }
1619         list_add(&cmd->list, &ftrace_commands);
1620  out_unlock:
1621         mutex_unlock(&ftrace_cmd_mutex);
1622
1623         return ret;
1624 }
1625
1626 int unregister_ftrace_command(struct ftrace_func_command *cmd)
1627 {
1628         struct ftrace_func_command *p, *n;
1629         int ret = -ENODEV;
1630
1631         mutex_lock(&ftrace_cmd_mutex);
1632         list_for_each_entry_safe(p, n, &ftrace_commands, list) {
1633                 if (strcmp(cmd->name, p->name) == 0) {
1634                         ret = 0;
1635                         list_del_init(&p->list);
1636                         goto out_unlock;
1637                 }
1638         }
1639  out_unlock:
1640         mutex_unlock(&ftrace_cmd_mutex);
1641
1642         return ret;
1643 }
1644
1645 static int ftrace_process_regex(char *buff, int len, int enable)
1646 {
1647         char *func, *command, *next = buff;
1648         struct ftrace_func_command *p;
1649         int ret = -EINVAL;
1650
1651         func = strsep(&next, ":");
1652
1653         if (!next) {
1654                 ftrace_match_records(func, len, enable);
1655                 return 0;
1656         }
1657
1658         /* command found */
1659
1660         command = strsep(&next, ":");
1661
1662         mutex_lock(&ftrace_cmd_mutex);
1663         list_for_each_entry(p, &ftrace_commands, list) {
1664                 if (strcmp(p->name, command) == 0) {
1665                         ret = p->func(func, command, next, enable);
1666                         goto out_unlock;
1667                 }
1668         }
1669  out_unlock:
1670         mutex_unlock(&ftrace_cmd_mutex);
1671
1672         return ret;
1673 }
1674
1675 static ssize_t
1676 ftrace_regex_write(struct file *file, const char __user *ubuf,
1677                    size_t cnt, loff_t *ppos, int enable)
1678 {
1679         struct ftrace_iterator *iter;
1680         char ch;
1681         size_t read = 0;
1682         ssize_t ret;
1683
1684         if (!cnt || cnt < 0)
1685                 return 0;
1686
1687         mutex_lock(&ftrace_regex_lock);
1688
1689         if (file->f_mode & FMODE_READ) {
1690                 struct seq_file *m = file->private_data;
1691                 iter = m->private;
1692         } else
1693                 iter = file->private_data;
1694
1695         if (!*ppos) {
1696                 iter->flags &= ~FTRACE_ITER_CONT;
1697                 iter->buffer_idx = 0;
1698         }
1699
1700         ret = get_user(ch, ubuf++);
1701         if (ret)
1702                 goto out;
1703         read++;
1704         cnt--;
1705
1706         if (!(iter->flags & ~FTRACE_ITER_CONT)) {
1707                 /* skip white space */
1708                 while (cnt && isspace(ch)) {
1709                         ret = get_user(ch, ubuf++);
1710                         if (ret)
1711                                 goto out;
1712                         read++;
1713                         cnt--;
1714                 }
1715
1716                 if (isspace(ch)) {
1717                         file->f_pos += read;
1718                         ret = read;
1719                         goto out;
1720                 }
1721
1722                 iter->buffer_idx = 0;
1723         }
1724
1725         while (cnt && !isspace(ch)) {
1726                 if (iter->buffer_idx < FTRACE_BUFF_MAX)
1727                         iter->buffer[iter->buffer_idx++] = ch;
1728                 else {
1729                         ret = -EINVAL;
1730                         goto out;
1731                 }
1732                 ret = get_user(ch, ubuf++);
1733                 if (ret)
1734                         goto out;
1735                 read++;
1736                 cnt--;
1737         }
1738
1739         if (isspace(ch)) {
1740                 iter->filtered++;
1741                 iter->buffer[iter->buffer_idx] = 0;
1742                 ret = ftrace_process_regex(iter->buffer,
1743                                            iter->buffer_idx, enable);
1744                 if (ret)
1745                         goto out;
1746                 iter->buffer_idx = 0;
1747         } else
1748                 iter->flags |= FTRACE_ITER_CONT;
1749
1750
1751         file->f_pos += read;
1752
1753         ret = read;
1754  out:
1755         mutex_unlock(&ftrace_regex_lock);
1756
1757         return ret;
1758 }
1759
1760 static ssize_t
1761 ftrace_filter_write(struct file *file, const char __user *ubuf,
1762                     size_t cnt, loff_t *ppos)
1763 {
1764         return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
1765 }
1766
1767 static ssize_t
1768 ftrace_notrace_write(struct file *file, const char __user *ubuf,
1769                      size_t cnt, loff_t *ppos)
1770 {
1771         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
1772 }
1773
1774 static void
1775 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
1776 {
1777         if (unlikely(ftrace_disabled))
1778                 return;
1779
1780         mutex_lock(&ftrace_regex_lock);
1781         if (reset)
1782                 ftrace_filter_reset(enable);
1783         if (buf)
1784                 ftrace_match_records(buf, len, enable);
1785         mutex_unlock(&ftrace_regex_lock);
1786 }
1787
1788 /**
1789  * ftrace_set_filter - set a function to filter on in ftrace
1790  * @buf - the string that holds the function filter text.
1791  * @len - the length of the string.
1792  * @reset - non zero to reset all filters before applying this filter.
1793  *
1794  * Filters denote which functions should be enabled when tracing is enabled.
1795  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
1796  */
1797 void ftrace_set_filter(unsigned char *buf, int len, int reset)
1798 {
1799         ftrace_set_regex(buf, len, reset, 1);
1800 }
1801
1802 /**
1803  * ftrace_set_notrace - set a function to not trace in ftrace
1804  * @buf - the string that holds the function notrace text.
1805  * @len - the length of the string.
1806  * @reset - non zero to reset all filters before applying this filter.
1807  *
1808  * Notrace Filters denote which functions should not be enabled when tracing
1809  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
1810  * for tracing.
1811  */
1812 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
1813 {
1814         ftrace_set_regex(buf, len, reset, 0);
1815 }
1816
1817 static int
1818 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
1819 {
1820         struct seq_file *m = (struct seq_file *)file->private_data;
1821         struct ftrace_iterator *iter;
1822
1823         mutex_lock(&ftrace_regex_lock);
1824         if (file->f_mode & FMODE_READ) {
1825                 iter = m->private;
1826
1827                 seq_release(inode, file);
1828         } else
1829                 iter = file->private_data;
1830
1831         if (iter->buffer_idx) {
1832                 iter->filtered++;
1833                 iter->buffer[iter->buffer_idx] = 0;
1834                 ftrace_match_records(iter->buffer, iter->buffer_idx, enable);
1835         }
1836
1837         mutex_lock(&ftrace_lock);
1838         if (ftrace_start_up && ftrace_enabled)
1839                 ftrace_run_update_code(FTRACE_ENABLE_CALLS);
1840         mutex_unlock(&ftrace_lock);
1841
1842         kfree(iter);
1843         mutex_unlock(&ftrace_regex_lock);
1844         return 0;
1845 }
1846
1847 static int
1848 ftrace_filter_release(struct inode *inode, struct file *file)
1849 {
1850         return ftrace_regex_release(inode, file, 1);
1851 }
1852
1853 static int
1854 ftrace_notrace_release(struct inode *inode, struct file *file)
1855 {
1856         return ftrace_regex_release(inode, file, 0);
1857 }
1858
1859 static const struct file_operations ftrace_avail_fops = {
1860         .open = ftrace_avail_open,
1861         .read = seq_read,
1862         .llseek = seq_lseek,
1863         .release = ftrace_avail_release,
1864 };
1865
1866 static const struct file_operations ftrace_failures_fops = {
1867         .open = ftrace_failures_open,
1868         .read = seq_read,
1869         .llseek = seq_lseek,
1870         .release = ftrace_avail_release,
1871 };
1872
1873 static const struct file_operations ftrace_filter_fops = {
1874         .open = ftrace_filter_open,
1875         .read = seq_read,
1876         .write = ftrace_filter_write,
1877         .llseek = ftrace_regex_lseek,
1878         .release = ftrace_filter_release,
1879 };
1880
1881 static const struct file_operations ftrace_notrace_fops = {
1882         .open = ftrace_notrace_open,
1883         .read = seq_read,
1884         .write = ftrace_notrace_write,
1885         .llseek = ftrace_regex_lseek,
1886         .release = ftrace_notrace_release,
1887 };
1888
1889 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1890
1891 static DEFINE_MUTEX(graph_lock);
1892
1893 int ftrace_graph_count;
1894 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
1895
1896 static void *
1897 g_next(struct seq_file *m, void *v, loff_t *pos)
1898 {
1899         unsigned long *array = m->private;
1900         int index = *pos;
1901
1902         (*pos)++;
1903
1904         if (index >= ftrace_graph_count)
1905                 return NULL;
1906
1907         return &array[index];
1908 }
1909
1910 static void *g_start(struct seq_file *m, loff_t *pos)
1911 {
1912         void *p = NULL;
1913
1914         mutex_lock(&graph_lock);
1915
1916         /* Nothing, tell g_show to print all functions are enabled */
1917         if (!ftrace_graph_count && !*pos)
1918                 return (void *)1;
1919
1920         p = g_next(m, p, pos);
1921
1922         return p;
1923 }
1924
1925 static void g_stop(struct seq_file *m, void *p)
1926 {
1927         mutex_unlock(&graph_lock);
1928 }
1929
1930 static int g_show(struct seq_file *m, void *v)
1931 {
1932         unsigned long *ptr = v;
1933         char str[KSYM_SYMBOL_LEN];
1934
1935         if (!ptr)
1936                 return 0;
1937
1938         if (ptr == (unsigned long *)1) {
1939                 seq_printf(m, "#### all functions enabled ####\n");
1940                 return 0;
1941         }
1942
1943         kallsyms_lookup(*ptr, NULL, NULL, NULL, str);
1944
1945         seq_printf(m, "%s\n", str);
1946
1947         return 0;
1948 }
1949
1950 static struct seq_operations ftrace_graph_seq_ops = {
1951         .start = g_start,
1952         .next = g_next,
1953         .stop = g_stop,
1954         .show = g_show,
1955 };
1956
1957 static int
1958 ftrace_graph_open(struct inode *inode, struct file *file)
1959 {
1960         int ret = 0;
1961
1962         if (unlikely(ftrace_disabled))
1963                 return -ENODEV;
1964
1965         mutex_lock(&graph_lock);
1966         if ((file->f_mode & FMODE_WRITE) &&
1967             !(file->f_flags & O_APPEND)) {
1968                 ftrace_graph_count = 0;
1969                 memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
1970         }
1971
1972         if (file->f_mode & FMODE_READ) {
1973                 ret = seq_open(file, &ftrace_graph_seq_ops);
1974                 if (!ret) {
1975                         struct seq_file *m = file->private_data;
1976                         m->private = ftrace_graph_funcs;
1977                 }
1978         } else
1979                 file->private_data = ftrace_graph_funcs;
1980         mutex_unlock(&graph_lock);
1981
1982         return ret;
1983 }
1984
1985 static int
1986 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
1987 {
1988         struct dyn_ftrace *rec;
1989         struct ftrace_page *pg;
1990         int search_len;
1991         int found = 0;
1992         int type, not;
1993         char *search;
1994         bool exists;
1995         int i;
1996
1997         if (ftrace_disabled)
1998                 return -ENODEV;
1999
2000         /* decode regex */
2001         type = ftrace_setup_glob(buffer, strlen(buffer), &search, &not);
2002         if (not)
2003                 return -EINVAL;
2004
2005         search_len = strlen(search);
2006
2007         mutex_lock(&ftrace_lock);
2008         do_for_each_ftrace_rec(pg, rec) {
2009
2010                 if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
2011                         break;
2012
2013                 if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
2014                         continue;
2015
2016                 if (ftrace_match_record(rec, search, search_len, type)) {
2017                         /* ensure it is not already in the array */
2018                         exists = false;
2019                         for (i = 0; i < *idx; i++)
2020                                 if (array[i] == rec->ip) {
2021                                         exists = true;
2022                                         break;
2023                                 }
2024                         if (!exists) {
2025                                 array[(*idx)++] = rec->ip;
2026                                 found = 1;
2027                         }
2028                 }
2029         } while_for_each_ftrace_rec();
2030
2031         mutex_unlock(&ftrace_lock);
2032
2033         return found ? 0 : -EINVAL;
2034 }
2035
2036 static ssize_t
2037 ftrace_graph_write(struct file *file, const char __user *ubuf,
2038                    size_t cnt, loff_t *ppos)
2039 {
2040         unsigned char buffer[FTRACE_BUFF_MAX+1];
2041         unsigned long *array;
2042         size_t read = 0;
2043         ssize_t ret;
2044         int index = 0;
2045         char ch;
2046
2047         if (!cnt || cnt < 0)
2048                 return 0;
2049
2050         mutex_lock(&graph_lock);
2051
2052         if (ftrace_graph_count >= FTRACE_GRAPH_MAX_FUNCS) {
2053                 ret = -EBUSY;
2054                 goto out;
2055         }
2056
2057         if (file->f_mode & FMODE_READ) {
2058                 struct seq_file *m = file->private_data;
2059                 array = m->private;
2060         } else
2061                 array = file->private_data;
2062
2063         ret = get_user(ch, ubuf++);
2064         if (ret)
2065                 goto out;
2066         read++;
2067         cnt--;
2068
2069         /* skip white space */
2070         while (cnt && isspace(ch)) {
2071                 ret = get_user(ch, ubuf++);
2072                 if (ret)
2073                         goto out;
2074                 read++;
2075                 cnt--;
2076         }
2077
2078         if (isspace(ch)) {
2079                 *ppos += read;
2080                 ret = read;
2081                 goto out;
2082         }
2083
2084         while (cnt && !isspace(ch)) {
2085                 if (index < FTRACE_BUFF_MAX)
2086                         buffer[index++] = ch;
2087                 else {
2088                         ret = -EINVAL;
2089                         goto out;
2090                 }
2091                 ret = get_user(ch, ubuf++);
2092                 if (ret)
2093                         goto out;
2094                 read++;
2095                 cnt--;
2096         }
2097         buffer[index] = 0;
2098
2099         /* we allow only one expression at a time */
2100         ret = ftrace_set_func(array, &ftrace_graph_count, buffer);
2101         if (ret)
2102                 goto out;
2103
2104         file->f_pos += read;
2105
2106         ret = read;
2107  out:
2108         mutex_unlock(&graph_lock);
2109
2110         return ret;
2111 }
2112
2113 static const struct file_operations ftrace_graph_fops = {
2114         .open = ftrace_graph_open,
2115         .read = seq_read,
2116         .write = ftrace_graph_write,
2117 };
2118 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2119
2120 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
2121 {
2122         struct dentry *entry;
2123
2124         entry = debugfs_create_file("available_filter_functions", 0444,
2125                                     d_tracer, NULL, &ftrace_avail_fops);
2126         if (!entry)
2127                 pr_warning("Could not create debugfs "
2128                            "'available_filter_functions' entry\n");
2129
2130         entry = debugfs_create_file("failures", 0444,
2131                                     d_tracer, NULL, &ftrace_failures_fops);
2132         if (!entry)
2133                 pr_warning("Could not create debugfs 'failures' entry\n");
2134
2135         entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer,
2136                                     NULL, &ftrace_filter_fops);
2137         if (!entry)
2138                 pr_warning("Could not create debugfs "
2139                            "'set_ftrace_filter' entry\n");
2140
2141         entry = debugfs_create_file("set_ftrace_notrace", 0644, d_tracer,
2142                                     NULL, &ftrace_notrace_fops);
2143         if (!entry)
2144                 pr_warning("Could not create debugfs "
2145                            "'set_ftrace_notrace' entry\n");
2146
2147 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2148         entry = debugfs_create_file("set_graph_function", 0444, d_tracer,
2149                                     NULL,
2150                                     &ftrace_graph_fops);
2151         if (!entry)
2152                 pr_warning("Could not create debugfs "
2153                            "'set_graph_function' entry\n");
2154 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
2155
2156         return 0;
2157 }
2158
2159 static int ftrace_convert_nops(struct module *mod,
2160                                unsigned long *start,
2161                                unsigned long *end)
2162 {
2163         unsigned long *p;
2164         unsigned long addr;
2165         unsigned long flags;
2166
2167         mutex_lock(&ftrace_lock);
2168         p = start;
2169         while (p < end) {
2170                 addr = ftrace_call_adjust(*p++);
2171                 /*
2172                  * Some architecture linkers will pad between
2173                  * the different mcount_loc sections of different
2174                  * object files to satisfy alignments.
2175                  * Skip any NULL pointers.
2176                  */
2177                 if (!addr)
2178                         continue;
2179                 ftrace_record_ip(addr);
2180         }
2181
2182         /* disable interrupts to prevent kstop machine */
2183         local_irq_save(flags);
2184         ftrace_update_code(mod);
2185         local_irq_restore(flags);
2186         mutex_unlock(&ftrace_lock);
2187
2188         return 0;
2189 }
2190
2191 void ftrace_init_module(struct module *mod,
2192                         unsigned long *start, unsigned long *end)
2193 {
2194         if (ftrace_disabled || start == end)
2195                 return;
2196         ftrace_convert_nops(mod, start, end);
2197 }
2198
2199 extern unsigned long __start_mcount_loc[];
2200 extern unsigned long __stop_mcount_loc[];
2201
2202 void __init ftrace_init(void)
2203 {
2204         unsigned long count, addr, flags;
2205         int ret;
2206
2207         /* Keep the ftrace pointer to the stub */
2208         addr = (unsigned long)ftrace_stub;
2209
2210         local_irq_save(flags);
2211         ftrace_dyn_arch_init(&addr);
2212         local_irq_restore(flags);
2213
2214         /* ftrace_dyn_arch_init places the return code in addr */
2215         if (addr)
2216                 goto failed;
2217
2218         count = __stop_mcount_loc - __start_mcount_loc;
2219
2220         ret = ftrace_dyn_table_alloc(count);
2221         if (ret)
2222                 goto failed;
2223
2224         last_ftrace_enabled = ftrace_enabled = 1;
2225
2226         ret = ftrace_convert_nops(NULL,
2227                                   __start_mcount_loc,
2228                                   __stop_mcount_loc);
2229
2230         return;
2231  failed:
2232         ftrace_disabled = 1;
2233 }
2234
2235 #else
2236
2237 static int __init ftrace_nodyn_init(void)
2238 {
2239         ftrace_enabled = 1;
2240         return 0;
2241 }
2242 device_initcall(ftrace_nodyn_init);
2243
2244 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
2245 static inline void ftrace_startup_enable(int command) { }
2246 /* Keep as macros so we do not need to define the commands */
2247 # define ftrace_startup(command)        do { } while (0)
2248 # define ftrace_shutdown(command)       do { } while (0)
2249 # define ftrace_startup_sysctl()        do { } while (0)
2250 # define ftrace_shutdown_sysctl()       do { } while (0)
2251 #endif /* CONFIG_DYNAMIC_FTRACE */
2252
2253 static ssize_t
2254 ftrace_pid_read(struct file *file, char __user *ubuf,
2255                        size_t cnt, loff_t *ppos)
2256 {
2257         char buf[64];
2258         int r;
2259
2260         if (ftrace_pid_trace == ftrace_swapper_pid)
2261                 r = sprintf(buf, "swapper tasks\n");
2262         else if (ftrace_pid_trace)
2263                 r = sprintf(buf, "%u\n", pid_nr(ftrace_pid_trace));
2264         else
2265                 r = sprintf(buf, "no pid\n");
2266
2267         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2268 }
2269
2270 static void clear_ftrace_swapper(void)
2271 {
2272         struct task_struct *p;
2273         int cpu;
2274
2275         get_online_cpus();
2276         for_each_online_cpu(cpu) {
2277                 p = idle_task(cpu);
2278                 clear_tsk_trace_trace(p);
2279         }
2280         put_online_cpus();
2281 }
2282
2283 static void set_ftrace_swapper(void)
2284 {
2285         struct task_struct *p;
2286         int cpu;
2287
2288         get_online_cpus();
2289         for_each_online_cpu(cpu) {
2290                 p = idle_task(cpu);
2291                 set_tsk_trace_trace(p);
2292         }
2293         put_online_cpus();
2294 }
2295
2296 static void clear_ftrace_pid(struct pid *pid)
2297 {
2298         struct task_struct *p;
2299
2300         rcu_read_lock();
2301         do_each_pid_task(pid, PIDTYPE_PID, p) {
2302                 clear_tsk_trace_trace(p);
2303         } while_each_pid_task(pid, PIDTYPE_PID, p);
2304         rcu_read_unlock();
2305
2306         put_pid(pid);
2307 }
2308
2309 static void set_ftrace_pid(struct pid *pid)
2310 {
2311         struct task_struct *p;
2312
2313         rcu_read_lock();
2314         do_each_pid_task(pid, PIDTYPE_PID, p) {
2315                 set_tsk_trace_trace(p);
2316         } while_each_pid_task(pid, PIDTYPE_PID, p);
2317         rcu_read_unlock();
2318 }
2319
2320 static void clear_ftrace_pid_task(struct pid **pid)
2321 {
2322         if (*pid == ftrace_swapper_pid)
2323                 clear_ftrace_swapper();
2324         else
2325                 clear_ftrace_pid(*pid);
2326
2327         *pid = NULL;
2328 }
2329
2330 static void set_ftrace_pid_task(struct pid *pid)
2331 {
2332         if (pid == ftrace_swapper_pid)
2333                 set_ftrace_swapper();
2334         else
2335                 set_ftrace_pid(pid);
2336 }
2337
2338 static ssize_t
2339 ftrace_pid_write(struct file *filp, const char __user *ubuf,
2340                    size_t cnt, loff_t *ppos)
2341 {
2342         struct pid *pid;
2343         char buf[64];
2344         long val;
2345         int ret;
2346
2347         if (cnt >= sizeof(buf))
2348                 return -EINVAL;
2349
2350         if (copy_from_user(&buf, ubuf, cnt))
2351                 return -EFAULT;
2352
2353         buf[cnt] = 0;
2354
2355         ret = strict_strtol(buf, 10, &val);
2356         if (ret < 0)
2357                 return ret;
2358
2359         mutex_lock(&ftrace_lock);
2360         if (val < 0) {
2361                 /* disable pid tracing */
2362                 if (!ftrace_pid_trace)
2363                         goto out;
2364
2365                 clear_ftrace_pid_task(&ftrace_pid_trace);
2366
2367         } else {
2368                 /* swapper task is special */
2369                 if (!val) {
2370                         pid = ftrace_swapper_pid;
2371                         if (pid == ftrace_pid_trace)
2372                                 goto out;
2373                 } else {
2374                         pid = find_get_pid(val);
2375
2376                         if (pid == ftrace_pid_trace) {
2377                                 put_pid(pid);
2378                                 goto out;
2379                         }
2380                 }
2381
2382                 if (ftrace_pid_trace)
2383                         clear_ftrace_pid_task(&ftrace_pid_trace);
2384
2385                 if (!pid)
2386                         goto out;
2387
2388                 ftrace_pid_trace = pid;
2389
2390                 set_ftrace_pid_task(ftrace_pid_trace);
2391         }
2392
2393         /* update the function call */
2394         ftrace_update_pid_func();
2395         ftrace_startup_enable(0);
2396
2397  out:
2398         mutex_unlock(&ftrace_lock);
2399
2400         return cnt;
2401 }
2402
2403 static const struct file_operations ftrace_pid_fops = {
2404         .read = ftrace_pid_read,
2405         .write = ftrace_pid_write,
2406 };
2407
2408 static __init int ftrace_init_debugfs(void)
2409 {
2410         struct dentry *d_tracer;
2411         struct dentry *entry;
2412
2413         d_tracer = tracing_init_dentry();
2414         if (!d_tracer)
2415                 return 0;
2416
2417         ftrace_init_dyn_debugfs(d_tracer);
2418
2419         entry = debugfs_create_file("set_ftrace_pid", 0644, d_tracer,
2420                                     NULL, &ftrace_pid_fops);
2421         if (!entry)
2422                 pr_warning("Could not create debugfs "
2423                            "'set_ftrace_pid' entry\n");
2424         return 0;
2425 }
2426 fs_initcall(ftrace_init_debugfs);
2427
2428 /**
2429  * ftrace_kill - kill ftrace
2430  *
2431  * This function should be used by panic code. It stops ftrace
2432  * but in a not so nice way. If you need to simply kill ftrace
2433  * from a non-atomic section, use ftrace_kill.
2434  */
2435 void ftrace_kill(void)
2436 {
2437         ftrace_disabled = 1;
2438         ftrace_enabled = 0;
2439         clear_ftrace_function();
2440 }
2441
2442 /**
2443  * register_ftrace_function - register a function for profiling
2444  * @ops - ops structure that holds the function for profiling.
2445  *
2446  * Register a function to be called by all functions in the
2447  * kernel.
2448  *
2449  * Note: @ops->func and all the functions it calls must be labeled
2450  *       with "notrace", otherwise it will go into a
2451  *       recursive loop.
2452  */
2453 int register_ftrace_function(struct ftrace_ops *ops)
2454 {
2455         int ret;
2456
2457         if (unlikely(ftrace_disabled))
2458                 return -1;
2459
2460         mutex_lock(&ftrace_lock);
2461
2462         ret = __register_ftrace_function(ops);
2463         ftrace_startup(0);
2464
2465         mutex_unlock(&ftrace_lock);
2466         return ret;
2467 }
2468
2469 /**
2470  * unregister_ftrace_function - unregister a function for profiling.
2471  * @ops - ops structure that holds the function to unregister
2472  *
2473  * Unregister a function that was added to be called by ftrace profiling.
2474  */
2475 int unregister_ftrace_function(struct ftrace_ops *ops)
2476 {
2477         int ret;
2478
2479         mutex_lock(&ftrace_lock);
2480         ret = __unregister_ftrace_function(ops);
2481         ftrace_shutdown(0);
2482         mutex_unlock(&ftrace_lock);
2483
2484         return ret;
2485 }
2486
2487 int
2488 ftrace_enable_sysctl(struct ctl_table *table, int write,
2489                      struct file *file, void __user *buffer, size_t *lenp,
2490                      loff_t *ppos)
2491 {
2492         int ret;
2493
2494         if (unlikely(ftrace_disabled))
2495                 return -ENODEV;
2496
2497         mutex_lock(&ftrace_lock);
2498
2499         ret  = proc_dointvec(table, write, file, buffer, lenp, ppos);
2500
2501         if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
2502                 goto out;
2503
2504         last_ftrace_enabled = ftrace_enabled;
2505
2506         if (ftrace_enabled) {
2507
2508                 ftrace_startup_sysctl();
2509
2510                 /* we are starting ftrace again */
2511                 if (ftrace_list != &ftrace_list_end) {
2512                         if (ftrace_list->next == &ftrace_list_end)
2513                                 ftrace_trace_function = ftrace_list->func;
2514                         else
2515                                 ftrace_trace_function = ftrace_list_func;
2516                 }
2517
2518         } else {
2519                 /* stopping ftrace calls (just send to ftrace_stub) */
2520                 ftrace_trace_function = ftrace_stub;
2521
2522                 ftrace_shutdown_sysctl();
2523         }
2524
2525  out:
2526         mutex_unlock(&ftrace_lock);
2527         return ret;
2528 }
2529
2530 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
2531
2532 static atomic_t ftrace_graph_active;
2533 static struct notifier_block ftrace_suspend_notifier;
2534
2535 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
2536 {
2537         return 0;
2538 }
2539
2540 /* The callbacks that hook a function */
2541 trace_func_graph_ret_t ftrace_graph_return =
2542                         (trace_func_graph_ret_t)ftrace_stub;
2543 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
2544
2545 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
2546 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
2547 {
2548         int i;
2549         int ret = 0;
2550         unsigned long flags;
2551         int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
2552         struct task_struct *g, *t;
2553
2554         for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
2555                 ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
2556                                         * sizeof(struct ftrace_ret_stack),
2557                                         GFP_KERNEL);
2558                 if (!ret_stack_list[i]) {
2559                         start = 0;
2560                         end = i;
2561                         ret = -ENOMEM;
2562                         goto free;
2563                 }
2564         }
2565
2566         read_lock_irqsave(&tasklist_lock, flags);
2567         do_each_thread(g, t) {
2568                 if (start == end) {
2569                         ret = -EAGAIN;
2570                         goto unlock;
2571                 }
2572
2573                 if (t->ret_stack == NULL) {
2574                         t->curr_ret_stack = -1;
2575                         /* Make sure IRQs see the -1 first: */
2576                         barrier();
2577                         t->ret_stack = ret_stack_list[start++];
2578                         atomic_set(&t->tracing_graph_pause, 0);
2579                         atomic_set(&t->trace_overrun, 0);
2580                 }
2581         } while_each_thread(g, t);
2582
2583 unlock:
2584         read_unlock_irqrestore(&tasklist_lock, flags);
2585 free:
2586         for (i = start; i < end; i++)
2587                 kfree(ret_stack_list[i]);
2588         return ret;
2589 }
2590
2591 /* Allocate a return stack for each task */
2592 static int start_graph_tracing(void)
2593 {
2594         struct ftrace_ret_stack **ret_stack_list;
2595         int ret, cpu;
2596
2597         ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
2598                                 sizeof(struct ftrace_ret_stack *),
2599                                 GFP_KERNEL);
2600
2601         if (!ret_stack_list)
2602                 return -ENOMEM;
2603
2604         /* The cpu_boot init_task->ret_stack will never be freed */
2605         for_each_online_cpu(cpu)
2606                 ftrace_graph_init_task(idle_task(cpu));
2607
2608         do {
2609                 ret = alloc_retstack_tasklist(ret_stack_list);
2610         } while (ret == -EAGAIN);
2611
2612         kfree(ret_stack_list);
2613         return ret;
2614 }
2615
2616 /*
2617  * Hibernation protection.
2618  * The state of the current task is too much unstable during
2619  * suspend/restore to disk. We want to protect against that.
2620  */
2621 static int
2622 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
2623                                                         void *unused)
2624 {
2625         switch (state) {
2626         case PM_HIBERNATION_PREPARE:
2627                 pause_graph_tracing();
2628                 break;
2629
2630         case PM_POST_HIBERNATION:
2631                 unpause_graph_tracing();
2632                 break;
2633         }
2634         return NOTIFY_DONE;
2635 }
2636
2637 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
2638                         trace_func_graph_ent_t entryfunc)
2639 {
2640         int ret = 0;
2641
2642         mutex_lock(&ftrace_lock);
2643
2644         ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
2645         register_pm_notifier(&ftrace_suspend_notifier);
2646
2647         atomic_inc(&ftrace_graph_active);
2648         ret = start_graph_tracing();
2649         if (ret) {
2650                 atomic_dec(&ftrace_graph_active);
2651                 goto out;
2652         }
2653
2654         ftrace_graph_return = retfunc;
2655         ftrace_graph_entry = entryfunc;
2656
2657         ftrace_startup(FTRACE_START_FUNC_RET);
2658
2659 out:
2660         mutex_unlock(&ftrace_lock);
2661         return ret;
2662 }
2663
2664 void unregister_ftrace_graph(void)
2665 {
2666         mutex_lock(&ftrace_lock);
2667
2668         atomic_dec(&ftrace_graph_active);
2669         ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
2670         ftrace_graph_entry = ftrace_graph_entry_stub;
2671         ftrace_shutdown(FTRACE_STOP_FUNC_RET);
2672         unregister_pm_notifier(&ftrace_suspend_notifier);
2673
2674         mutex_unlock(&ftrace_lock);
2675 }
2676
2677 /* Allocate a return stack for newly created task */
2678 void ftrace_graph_init_task(struct task_struct *t)
2679 {
2680         if (atomic_read(&ftrace_graph_active)) {
2681                 t->ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
2682                                 * sizeof(struct ftrace_ret_stack),
2683                                 GFP_KERNEL);
2684                 if (!t->ret_stack)
2685                         return;
2686                 t->curr_ret_stack = -1;
2687                 atomic_set(&t->tracing_graph_pause, 0);
2688                 atomic_set(&t->trace_overrun, 0);
2689         } else
2690                 t->ret_stack = NULL;
2691 }
2692
2693 void ftrace_graph_exit_task(struct task_struct *t)
2694 {
2695         struct ftrace_ret_stack *ret_stack = t->ret_stack;
2696
2697         t->ret_stack = NULL;
2698         /* NULL must become visible to IRQs before we free it: */
2699         barrier();
2700
2701         kfree(ret_stack);
2702 }
2703
2704 void ftrace_graph_stop(void)
2705 {
2706         ftrace_stop();
2707 }
2708 #endif
2709