kernel/trace/trace_kprobe.c

   1 /*
   2  * Kprobes-based tracing events
   3  *
   4  * Created by Masami Hiramatsu <mhiramat@redhat.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/uaccess.h>
  22
  23 #include "trace_probe.h"
  24
  25 #define KPROBE_EVENT_SYSTEM "kprobes"
  26
  27 /**
  28  * Kprobe event core functions
  29  */
  30 struct trace_kprobe {
  31         struct list_head        list;
  32         struct kretprobe        rp;     /* Use rp.kp for kprobe use */
  33         unsigned long __percpu *nhit;
  34         const char              *symbol;        /* symbol name */
  35         struct trace_probe      tp;
  36 };
  37
  38 #define SIZEOF_TRACE_KPROBE(n)                          \
  39         (offsetof(struct trace_kprobe, tp.args) +       \
  40         (sizeof(struct probe_arg) * (n)))
  41
  42
  43 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
  44 {
  45         return tk->rp.handler != NULL;
  46 }
  47
  48 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
  49 {
  50         return tk->symbol ? tk->symbol : "unknown";
  51 }
  52
  53 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
  54 {
  55         return tk->rp.kp.offset;
  56 }
  57
  58 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
  59 {
  60         return !!(kprobe_gone(&tk->rp.kp));
  61 }
  62
  63 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
  64                                                  struct module *mod)
  65 {
  66         int len = strlen(mod->name);
  67         const char *name = trace_kprobe_symbol(tk);
  68         return strncmp(mod->name, name, len) == 0 && name[len] == ':';
  69 }
  70
  71 static nokprobe_inline bool trace_kprobe_is_on_module(struct trace_kprobe *tk)
  72 {
  73         return !!strchr(trace_kprobe_symbol(tk), ':');
  74 }
  75
  76 static int register_kprobe_event(struct trace_kprobe *tk);
  77 static int unregister_kprobe_event(struct trace_kprobe *tk);
  78
  79 static DEFINE_MUTEX(probe_lock);
  80 static LIST_HEAD(probe_list);
  81
  82 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
  83 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
  84                                 struct pt_regs *regs);
  85
  86 /* Memory fetching by symbol */
  87 struct symbol_cache {
  88         char            *symbol;
  89         long            offset;
  90         unsigned long   addr;
  91 };
  92
  93 unsigned long update_symbol_cache(struct symbol_cache *sc)
  94 {
  95         sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
  96
  97         if (sc->addr)
  98                 sc->addr += sc->offset;
  99
 100         return sc->addr;
 101 }
 102
 103 void free_symbol_cache(struct symbol_cache *sc)
 104 {
 105         kfree(sc->symbol);
 106         kfree(sc);
 107 }
 108
 109 struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
 110 {
 111         struct symbol_cache *sc;
 112
 113         if (!sym || strlen(sym) == 0)
 114                 return NULL;
 115
 116         sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
 117         if (!sc)
 118                 return NULL;
 119
 120         sc->symbol = kstrdup(sym, GFP_KERNEL);
 121         if (!sc->symbol) {
 122                 kfree(sc);
 123                 return NULL;
 124         }
 125         sc->offset = offset;
 126         update_symbol_cache(sc);
 127
 128         return sc;
 129 }
 130
 131 /*
 132  * Kprobes-specific fetch functions
 133  */
 134 #define DEFINE_FETCH_stack(type)                                        \
 135 static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,          \
 136                                           void *offset, void *dest)     \
 137 {                                                                       \
 138         *(type *)dest = (type)regs_get_kernel_stack_nth(regs,           \
 139                                 (unsigned int)((unsigned long)offset)); \
 140 }                                                                       \
 141 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(stack, type));
 142
 143 DEFINE_BASIC_FETCH_FUNCS(stack)
 144 /* No string on the stack entry */
 145 #define fetch_stack_string      NULL
 146 #define fetch_stack_string_size NULL
 147
 148 #define DEFINE_FETCH_memory(type)                                       \
 149 static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,         \
 150                                           void *addr, void *dest)       \
 151 {                                                                       \
 152         type retval;                                                    \
 153         if (probe_kernel_address(addr, retval))                         \
 154                 *(type *)dest = 0;                                      \
 155         else                                                            \
 156                 *(type *)dest = retval;                                 \
 157 }                                                                       \
 158 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, type));
 159
 160 DEFINE_BASIC_FETCH_FUNCS(memory)
 161 /*
 162  * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
 163  * length and relative data location.
 164  */
 165 static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
 166                                             void *addr, void *dest)
 167 {
 168         int maxlen = get_rloc_len(*(u32 *)dest);
 169         u8 *dst = get_rloc_data(dest);
 170         long ret;
 171
 172         if (!maxlen)
 173                 return;
 174
 175         /*
 176          * Try to get string again, since the string can be changed while
 177          * probing.
 178          */
 179         ret = strncpy_from_unsafe(dst, addr, maxlen);
 180
 181         if (ret < 0) {  /* Failed to fetch string */
 182                 dst[0] = '\0';
 183                 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
 184         } else {
 185                 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
 186         }
 187 }
 188 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string));
 189
 190 /* Return the length of string -- including null terminal byte */
 191 static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
 192                                                  void *addr, void *dest)
 193 {
 194         mm_segment_t old_fs;
 195         int ret, len = 0;
 196         u8 c;
 197
 198         old_fs = get_fs();
 199         set_fs(KERNEL_DS);
 200         pagefault_disable();
 201
 202         do {
 203                 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
 204                 len++;
 205         } while (c && ret == 0 && len < MAX_STRING_SIZE);
 206
 207         pagefault_enable();
 208         set_fs(old_fs);
 209
 210         if (ret < 0)    /* Failed to check the length */
 211                 *(u32 *)dest = 0;
 212         else
 213                 *(u32 *)dest = len;
 214 }
 215 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string_size));
 216
 217 #define DEFINE_FETCH_symbol(type)                                       \
 218 void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs, void *data, void *dest)\
 219 {                                                                       \
 220         struct symbol_cache *sc = data;                                 \
 221         if (sc->addr)                                                   \
 222                 fetch_memory_##type(regs, (void *)sc->addr, dest);      \
 223         else                                                            \
 224                 *(type *)dest = 0;                                      \
 225 }                                                                       \
 226 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(symbol, type));
 227
 228 DEFINE_BASIC_FETCH_FUNCS(symbol)
 229 DEFINE_FETCH_symbol(string)
 230 DEFINE_FETCH_symbol(string_size)
 231
 232 /* kprobes don't support file_offset fetch methods */
 233 #define fetch_file_offset_u8            NULL
 234 #define fetch_file_offset_u16           NULL
 235 #define fetch_file_offset_u32           NULL
 236 #define fetch_file_offset_u64           NULL
 237 #define fetch_file_offset_string        NULL
 238 #define fetch_file_offset_string_size   NULL
 239
 240 /* Fetch type information table */
 241 static const struct fetch_type kprobes_fetch_type_table[] = {
 242         /* Special types */
 243         [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
 244                                         sizeof(u32), 1, "__data_loc char[]"),
 245         [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
 246                                         string_size, sizeof(u32), 0, "u32"),
 247         /* Basic types */
 248         ASSIGN_FETCH_TYPE(u8,  u8,  0),
 249         ASSIGN_FETCH_TYPE(u16, u16, 0),
 250         ASSIGN_FETCH_TYPE(u32, u32, 0),
 251         ASSIGN_FETCH_TYPE(u64, u64, 0),
 252         ASSIGN_FETCH_TYPE(s8,  u8,  1),
 253         ASSIGN_FETCH_TYPE(s16, u16, 1),
 254         ASSIGN_FETCH_TYPE(s32, u32, 1),
 255         ASSIGN_FETCH_TYPE(s64, u64, 1),
 256
 257         ASSIGN_FETCH_TYPE_END
 258 };
 259
 260 /*
 261  * Allocate new trace_probe and initialize it (including kprobes).
 262  */
 263 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
 264                                              const char *event,
 265                                              void *addr,
 266                                              const char *symbol,
 267                                              unsigned long offs,
 268                                              int nargs, bool is_return)
 269 {
 270         struct trace_kprobe *tk;
 271         int ret = -ENOMEM;
 272
 273         tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
 274         if (!tk)
 275                 return ERR_PTR(ret);
 276
 277         tk->nhit = alloc_percpu(unsigned long);
 278         if (!tk->nhit)
 279                 goto error;
 280
 281         if (symbol) {
 282                 tk->symbol = kstrdup(symbol, GFP_KERNEL);
 283                 if (!tk->symbol)
 284                         goto error;
 285                 tk->rp.kp.symbol_name = tk->symbol;
 286                 tk->rp.kp.offset = offs;
 287         } else
 288                 tk->rp.kp.addr = addr;
 289
 290         if (is_return)
 291                 tk->rp.handler = kretprobe_dispatcher;
 292         else
 293                 tk->rp.kp.pre_handler = kprobe_dispatcher;
 294
 295         if (!event || !is_good_name(event)) {
 296                 ret = -EINVAL;
 297                 goto error;
 298         }
 299
 300         tk->tp.call.class = &tk->tp.class;
 301         tk->tp.call.name = kstrdup(event, GFP_KERNEL);
 302         if (!tk->tp.call.name)
 303                 goto error;
 304
 305         if (!group || !is_good_name(group)) {
 306                 ret = -EINVAL;
 307                 goto error;
 308         }
 309
 310         tk->tp.class.system = kstrdup(group, GFP_KERNEL);
 311         if (!tk->tp.class.system)
 312                 goto error;
 313
 314         INIT_LIST_HEAD(&tk->list);
 315         INIT_LIST_HEAD(&tk->tp.files);
 316         return tk;
 317 error:
 318         kfree(tk->tp.call.name);
 319         kfree(tk->symbol);
 320         free_percpu(tk->nhit);
 321         kfree(tk);
 322         return ERR_PTR(ret);
 323 }
 324
 325 static void free_trace_kprobe(struct trace_kprobe *tk)
 326 {
 327         int i;
 328
 329         for (i = 0; i < tk->tp.nr_args; i++)
 330                 traceprobe_free_probe_arg(&tk->tp.args[i]);
 331
 332         kfree(tk->tp.call.class->system);
 333         kfree(tk->tp.call.name);
 334         kfree(tk->symbol);
 335         free_percpu(tk->nhit);
 336         kfree(tk);
 337 }
 338
 339 static struct trace_kprobe *find_trace_kprobe(const char *event,
 340                                               const char *group)
 341 {
 342         struct trace_kprobe *tk;
 343
 344         list_for_each_entry(tk, &probe_list, list)
 345                 if (strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
 346                     strcmp(tk->tp.call.class->system, group) == 0)
 347                         return tk;
 348         return NULL;
 349 }
 350
 351 /*
 352  * Enable trace_probe
 353  * if the file is NULL, enable "perf" handler, or enable "trace" handler.
 354  */
 355 static int
 356 enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
 357 {
 358         int ret = 0;
 359
 360         if (file) {
 361                 struct event_file_link *link;
 362
 363                 link = kmalloc(sizeof(*link), GFP_KERNEL);
 364                 if (!link) {
 365                         ret = -ENOMEM;
 366                         goto out;
 367                 }
 368
 369                 link->file = file;
 370                 list_add_tail_rcu(&link->list, &tk->tp.files);
 371
 372                 tk->tp.flags |= TP_FLAG_TRACE;
 373         } else
 374                 tk->tp.flags |= TP_FLAG_PROFILE;
 375
 376         if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
 377                 if (trace_kprobe_is_return(tk))
 378                         ret = enable_kretprobe(&tk->rp);
 379                 else
 380                         ret = enable_kprobe(&tk->rp.kp);
 381         }
 382  out:
 383         return ret;
 384 }
 385
 386 /*
 387  * Disable trace_probe
 388  * if the file is NULL, disable "perf" handler, or disable "trace" handler.
 389  */
 390 static int
 391 disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
 392 {
 393         struct event_file_link *link = NULL;
 394         int wait = 0;
 395         int ret = 0;
 396
 397         if (file) {
 398                 link = find_event_file_link(&tk->tp, file);
 399                 if (!link) {
 400                         ret = -EINVAL;
 401                         goto out;
 402                 }
 403
 404                 list_del_rcu(&link->list);
 405                 wait = 1;
 406                 if (!list_empty(&tk->tp.files))
 407                         goto out;
 408
 409                 tk->tp.flags &= ~TP_FLAG_TRACE;
 410         } else
 411                 tk->tp.flags &= ~TP_FLAG_PROFILE;
 412
 413         if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
 414                 if (trace_kprobe_is_return(tk))
 415                         disable_kretprobe(&tk->rp);
 416                 else
 417                         disable_kprobe(&tk->rp.kp);
 418                 wait = 1;
 419         }
 420  out:
 421         if (wait) {
 422                 /*
 423                  * Synchronize with kprobe_trace_func/kretprobe_trace_func
 424                  * to ensure disabled (all running handlers are finished).
 425                  * This is not only for kfree(), but also the caller,
 426                  * trace_remove_event_call() supposes it for releasing
 427                  * event_call related objects, which will be accessed in
 428                  * the kprobe_trace_func/kretprobe_trace_func.
 429                  */
 430                 synchronize_sched();
 431                 kfree(link);    /* Ignored if link == NULL */
 432         }
 433
 434         return ret;
 435 }
 436
 437 /* Internal register function - just handle k*probes and flags */
 438 static int __register_trace_kprobe(struct trace_kprobe *tk)
 439 {
 440         int i, ret;
 441
 442         if (trace_probe_is_registered(&tk->tp))
 443                 return -EINVAL;
 444
 445         for (i = 0; i < tk->tp.nr_args; i++)
 446                 traceprobe_update_arg(&tk->tp.args[i]);
 447
 448         /* Set/clear disabled flag according to tp->flag */
 449         if (trace_probe_is_enabled(&tk->tp))
 450                 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
 451         else
 452                 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 453
 454         if (trace_kprobe_is_return(tk))
 455                 ret = register_kretprobe(&tk->rp);
 456         else
 457                 ret = register_kprobe(&tk->rp.kp);
 458
 459         if (ret == 0)
 460                 tk->tp.flags |= TP_FLAG_REGISTERED;
 461         else {
 462                 pr_warn("Could not insert probe at %s+%lu: %d\n",
 463                         trace_kprobe_symbol(tk), trace_kprobe_offset(tk), ret);
 464                 if (ret == -ENOENT && trace_kprobe_is_on_module(tk)) {
 465                         pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
 466                         ret = 0;
 467                 } else if (ret == -EILSEQ) {
 468                         pr_warn("Probing address(0x%p) is not an instruction boundary.\n",
 469                                 tk->rp.kp.addr);
 470                         ret = -EINVAL;
 471                 }
 472         }
 473
 474         return ret;
 475 }
 476
 477 /* Internal unregister function - just handle k*probes and flags */
 478 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
 479 {
 480         if (trace_probe_is_registered(&tk->tp)) {
 481                 if (trace_kprobe_is_return(tk))
 482                         unregister_kretprobe(&tk->rp);
 483                 else
 484                         unregister_kprobe(&tk->rp.kp);
 485                 tk->tp.flags &= ~TP_FLAG_REGISTERED;
 486                 /* Cleanup kprobe for reuse */
 487                 if (tk->rp.kp.symbol_name)
 488                         tk->rp.kp.addr = NULL;
 489         }
 490 }
 491
 492 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
 493 static int unregister_trace_kprobe(struct trace_kprobe *tk)
 494 {
 495         /* Enabled event can not be unregistered */
 496         if (trace_probe_is_enabled(&tk->tp))
 497                 return -EBUSY;
 498
 499         /* Will fail if probe is being used by ftrace or perf */
 500         if (unregister_kprobe_event(tk))
 501                 return -EBUSY;
 502
 503         __unregister_trace_kprobe(tk);
 504         list_del(&tk->list);
 505
 506         return 0;
 507 }
 508
 509 /* Register a trace_probe and probe_event */
 510 static int register_trace_kprobe(struct trace_kprobe *tk)
 511 {
 512         struct trace_kprobe *old_tk;
 513         int ret;
 514
 515         mutex_lock(&probe_lock);
 516
 517         /* Delete old (same name) event if exist */
 518         old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call),
 519                         tk->tp.call.class->system);
 520         if (old_tk) {
 521                 ret = unregister_trace_kprobe(old_tk);
 522                 if (ret < 0)
 523                         goto end;
 524                 free_trace_kprobe(old_tk);
 525         }
 526
 527         /* Register new event */
 528         ret = register_kprobe_event(tk);
 529         if (ret) {
 530                 pr_warn("Failed to register probe event(%d)\n", ret);
 531                 goto end;
 532         }
 533
 534         /* Register k*probe */
 535         ret = __register_trace_kprobe(tk);
 536         if (ret < 0)
 537                 unregister_kprobe_event(tk);
 538         else
 539                 list_add_tail(&tk->list, &probe_list);
 540
 541 end:
 542         mutex_unlock(&probe_lock);
 543         return ret;
 544 }
 545
 546 /* Module notifier call back, checking event on the module */
 547 static int trace_kprobe_module_callback(struct notifier_block *nb,
 548                                        unsigned long val, void *data)
 549 {
 550         struct module *mod = data;
 551         struct trace_kprobe *tk;
 552         int ret;
 553
 554         if (val != MODULE_STATE_COMING)
 555                 return NOTIFY_DONE;
 556
 557         /* Update probes on coming module */
 558         mutex_lock(&probe_lock);
 559         list_for_each_entry(tk, &probe_list, list) {
 560                 if (trace_kprobe_within_module(tk, mod)) {
 561                         /* Don't need to check busy - this should have gone. */
 562                         __unregister_trace_kprobe(tk);
 563                         ret = __register_trace_kprobe(tk);
 564                         if (ret)
 565                                 pr_warn("Failed to re-register probe %s on %s: %d\n",
 566                                         trace_event_name(&tk->tp.call),
 567                                         mod->name, ret);
 568                 }
 569         }
 570         mutex_unlock(&probe_lock);
 571
 572         return NOTIFY_DONE;
 573 }
 574
 575 static struct notifier_block trace_kprobe_module_nb = {
 576         .notifier_call = trace_kprobe_module_callback,
 577         .priority = 1   /* Invoked after kprobe module callback */
 578 };
 579
 580 static int create_trace_kprobe(int argc, char **argv)
 581 {
 582         /*
 583          * Argument syntax:
 584          *  - Add kprobe: p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
 585          *  - Add kretprobe: r[:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
 586          * Fetch args:
 587          *  $retval     : fetch return value
 588          *  $stack      : fetch stack address
 589          *  $stackN     : fetch Nth of stack (N:0-)
 590          *  $comm       : fetch current task comm
 591          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 592          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 593          *  %REG        : fetch register REG
 594          * Dereferencing memory fetch:
 595          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 596          * Alias name of args:
 597          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 598          * Type of args:
 599          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 600          */
 601         struct trace_kprobe *tk;
 602         int i, ret = 0;
 603         bool is_return = false, is_delete = false;
 604         char *symbol = NULL, *event = NULL, *group = NULL;
 605         char *arg;
 606         unsigned long offset = 0;
 607         void *addr = NULL;
 608         char buf[MAX_EVENT_NAME_LEN];
 609
 610         /* argc must be >= 1 */
 611         if (argv[0][0] == 'p')
 612                 is_return = false;
 613         else if (argv[0][0] == 'r')
 614                 is_return = true;
 615         else if (argv[0][0] == '-')
 616                 is_delete = true;
 617         else {
 618                 pr_info("Probe definition must be started with 'p', 'r' or"
 619                         " '-'.\n");
 620                 return -EINVAL;
 621         }
 622
 623         if (argv[0][1] == ':') {
 624                 event = &argv[0][2];
 625                 if (strchr(event, '/')) {
 626                         group = event;
 627                         event = strchr(group, '/') + 1;
 628                         event[-1] = '\0';
 629                         if (strlen(group) == 0) {
 630                                 pr_info("Group name is not specified\n");
 631                                 return -EINVAL;
 632                         }
 633                 }
 634                 if (strlen(event) == 0) {
 635                         pr_info("Event name is not specified\n");
 636                         return -EINVAL;
 637                 }
 638         }
 639         if (!group)
 640                 group = KPROBE_EVENT_SYSTEM;
 641
 642         if (is_delete) {
 643                 if (!event) {
 644                         pr_info("Delete command needs an event name.\n");
 645                         return -EINVAL;
 646                 }
 647                 mutex_lock(&probe_lock);
 648                 tk = find_trace_kprobe(event, group);
 649                 if (!tk) {
 650                         mutex_unlock(&probe_lock);
 651                         pr_info("Event %s/%s doesn't exist.\n", group, event);
 652                         return -ENOENT;
 653                 }
 654                 /* delete an event */
 655                 ret = unregister_trace_kprobe(tk);
 656                 if (ret == 0)
 657                         free_trace_kprobe(tk);
 658                 mutex_unlock(&probe_lock);
 659                 return ret;
 660         }
 661
 662         if (argc < 2) {
 663                 pr_info("Probe point is not specified.\n");
 664                 return -EINVAL;
 665         }
 666         if (isdigit(argv[1][0])) {
 667                 if (is_return) {
 668                         pr_info("Return probe point must be a symbol.\n");
 669                         return -EINVAL;
 670                 }
 671                 /* an address specified */
 672                 ret = kstrtoul(&argv[1][0], 0, (unsigned long *)&addr);
 673                 if (ret) {
 674                         pr_info("Failed to parse address.\n");
 675                         return ret;
 676                 }
 677         } else {
 678                 /* a symbol specified */
 679                 symbol = argv[1];
 680                 /* TODO: support .init module functions */
 681                 ret = traceprobe_split_symbol_offset(symbol, &offset);
 682                 if (ret) {
 683                         pr_info("Failed to parse symbol.\n");
 684                         return ret;
 685                 }
 686                 if (offset && is_return) {
 687                         pr_info("Return probe must be used without offset.\n");
 688                         return -EINVAL;
 689                 }
 690         }
 691         argc -= 2; argv += 2;
 692
 693         /* setup a probe */
 694         if (!event) {
 695                 /* Make a new event name */
 696                 if (symbol)
 697                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 698                                  is_return ? 'r' : 'p', symbol, offset);
 699                 else
 700                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 701                                  is_return ? 'r' : 'p', addr);
 702                 event = buf;
 703         }
 704         tk = alloc_trace_kprobe(group, event, addr, symbol, offset, argc,
 705                                is_return);
 706         if (IS_ERR(tk)) {
 707                 pr_info("Failed to allocate trace_probe.(%d)\n",
 708                         (int)PTR_ERR(tk));
 709                 return PTR_ERR(tk);
 710         }
 711
 712         /* parse arguments */
 713         ret = 0;
 714         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 715                 struct probe_arg *parg = &tk->tp.args[i];
 716
 717                 /* Increment count for freeing args in error case */
 718                 tk->tp.nr_args++;
 719
 720                 /* Parse argument name */
 721                 arg = strchr(argv[i], '=');
 722                 if (arg) {
 723                         *arg++ = '\0';
 724                         parg->name = kstrdup(argv[i], GFP_KERNEL);
 725                 } else {
 726                         arg = argv[i];
 727                         /* If argument name is omitted, set "argN" */
 728                         snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
 729                         parg->name = kstrdup(buf, GFP_KERNEL);
 730                 }
 731
 732                 if (!parg->name) {
 733                         pr_info("Failed to allocate argument[%d] name.\n", i);
 734                         ret = -ENOMEM;
 735                         goto error;
 736                 }
 737
 738                 if (!is_good_name(parg->name)) {
 739                         pr_info("Invalid argument[%d] name: %s\n",
 740                                 i, parg->name);
 741                         ret = -EINVAL;
 742                         goto error;
 743                 }
 744
 745                 if (traceprobe_conflict_field_name(parg->name,
 746                                                         tk->tp.args, i)) {
 747                         pr_info("Argument[%d] name '%s' conflicts with "
 748                                 "another field.\n", i, argv[i]);
 749                         ret = -EINVAL;
 750                         goto error;
 751                 }
 752
 753                 /* Parse fetch argument */
 754                 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
 755                                                 is_return, true,
 756                                                 kprobes_fetch_type_table);
 757                 if (ret) {
 758                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
 759                         goto error;
 760                 }
 761         }
 762
 763         ret = register_trace_kprobe(tk);
 764         if (ret)
 765                 goto error;
 766         return 0;
 767
 768 error:
 769         free_trace_kprobe(tk);
 770         return ret;
 771 }
 772
 773 static int release_all_trace_kprobes(void)
 774 {
 775         struct trace_kprobe *tk;
 776         int ret = 0;
 777
 778         mutex_lock(&probe_lock);
 779         /* Ensure no probe is in use. */
 780         list_for_each_entry(tk, &probe_list, list)
 781                 if (trace_probe_is_enabled(&tk->tp)) {
 782                         ret = -EBUSY;
 783                         goto end;
 784                 }
 785         /* TODO: Use batch unregistration */
 786         while (!list_empty(&probe_list)) {
 787                 tk = list_entry(probe_list.next, struct trace_kprobe, list);
 788                 ret = unregister_trace_kprobe(tk);
 789                 if (ret)
 790                         goto end;
 791                 free_trace_kprobe(tk);
 792         }
 793
 794 end:
 795         mutex_unlock(&probe_lock);
 796
 797         return ret;
 798 }
 799
 800 /* Probes listing interfaces */
 801 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
 802 {
 803         mutex_lock(&probe_lock);
 804         return seq_list_start(&probe_list, *pos);
 805 }
 806
 807 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
 808 {
 809         return seq_list_next(v, &probe_list, pos);
 810 }
 811
 812 static void probes_seq_stop(struct seq_file *m, void *v)
 813 {
 814         mutex_unlock(&probe_lock);
 815 }
 816
 817 static int probes_seq_show(struct seq_file *m, void *v)
 818 {
 819         struct trace_kprobe *tk = v;
 820         int i;
 821
 822         seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
 823         seq_printf(m, ":%s/%s", tk->tp.call.class->system,
 824                         trace_event_name(&tk->tp.call));
 825
 826         if (!tk->symbol)
 827                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
 828         else if (tk->rp.kp.offset)
 829                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
 830                            tk->rp.kp.offset);
 831         else
 832                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
 833
 834         for (i = 0; i < tk->tp.nr_args; i++)
 835                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
 836         seq_putc(m, '\n');
 837
 838         return 0;
 839 }
 840
 841 static const struct seq_operations probes_seq_op = {
 842         .start  = probes_seq_start,
 843         .next   = probes_seq_next,
 844         .stop   = probes_seq_stop,
 845         .show   = probes_seq_show
 846 };
 847
 848 static int probes_open(struct inode *inode, struct file *file)
 849 {
 850         int ret;
 851
 852         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
 853                 ret = release_all_trace_kprobes();
 854                 if (ret < 0)
 855                         return ret;
 856         }
 857
 858         return seq_open(file, &probes_seq_op);
 859 }
 860
 861 static ssize_t probes_write(struct file *file, const char __user *buffer,
 862                             size_t count, loff_t *ppos)
 863 {
 864         return traceprobe_probes_write(file, buffer, count, ppos,
 865                         create_trace_kprobe);
 866 }
 867
 868 static const struct file_operations kprobe_events_ops = {
 869         .owner          = THIS_MODULE,
 870         .open           = probes_open,
 871         .read           = seq_read,
 872         .llseek         = seq_lseek,
 873         .release        = seq_release,
 874         .write          = probes_write,
 875 };
 876
 877 /* Probes profiling interfaces */
 878 static int probes_profile_seq_show(struct seq_file *m, void *v)
 879 {
 880         struct trace_kprobe *tk = v;
 881         unsigned long nhit = 0;
 882         int cpu;
 883
 884         for_each_possible_cpu(cpu)
 885                 nhit += *per_cpu_ptr(tk->nhit, cpu);
 886
 887         seq_printf(m, "  %-44s %15lu %15lu\n",
 888                    trace_event_name(&tk->tp.call), nhit,
 889                    tk->rp.kp.nmissed);
 890
 891         return 0;
 892 }
 893
 894 static const struct seq_operations profile_seq_op = {
 895         .start  = probes_seq_start,
 896         .next   = probes_seq_next,
 897         .stop   = probes_seq_stop,
 898         .show   = probes_profile_seq_show
 899 };
 900
 901 static int profile_open(struct inode *inode, struct file *file)
 902 {
 903         return seq_open(file, &profile_seq_op);
 904 }
 905
 906 static const struct file_operations kprobe_profile_ops = {
 907         .owner          = THIS_MODULE,
 908         .open           = profile_open,
 909         .read           = seq_read,
 910         .llseek         = seq_lseek,
 911         .release        = seq_release,
 912 };
 913
 914 /* Kprobe handler */
 915 static nokprobe_inline void
 916 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
 917                     struct trace_event_file *trace_file)
 918 {
 919         struct kprobe_trace_entry_head *entry;
 920         struct ring_buffer_event *event;
 921         struct ring_buffer *buffer;
 922         int size, dsize, pc;
 923         unsigned long irq_flags;
 924         struct trace_event_call *call = &tk->tp.call;
 925
 926         WARN_ON(call != trace_file->event_call);
 927
 928         if (trace_trigger_soft_disabled(trace_file))
 929                 return;
 930
 931         local_save_flags(irq_flags);
 932         pc = preempt_count();
 933
 934         dsize = __get_data_size(&tk->tp, regs);
 935         size = sizeof(*entry) + tk->tp.size + dsize;
 936
 937         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
 938                                                 call->event.type,
 939                                                 size, irq_flags, pc);
 940         if (!event)
 941                 return;
 942
 943         entry = ring_buffer_event_data(event);
 944         entry->ip = (unsigned long)tk->rp.kp.addr;
 945         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
 946
 947         event_trigger_unlock_commit_regs(trace_file, buffer, event,
 948                                          entry, irq_flags, pc, regs);
 949 }
 950
 951 static void
 952 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
 953 {
 954         struct event_file_link *link;
 955
 956         list_for_each_entry_rcu(link, &tk->tp.files, list)
 957                 __kprobe_trace_func(tk, regs, link->file);
 958 }
 959 NOKPROBE_SYMBOL(kprobe_trace_func);
 960
 961 /* Kretprobe handler */
 962 static nokprobe_inline void
 963 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
 964                        struct pt_regs *regs,
 965                        struct trace_event_file *trace_file)
 966 {
 967         struct kretprobe_trace_entry_head *entry;
 968         struct ring_buffer_event *event;
 969         struct ring_buffer *buffer;
 970         int size, pc, dsize;
 971         unsigned long irq_flags;
 972         struct trace_event_call *call = &tk->tp.call;
 973
 974         WARN_ON(call != trace_file->event_call);
 975
 976         if (trace_trigger_soft_disabled(trace_file))
 977                 return;
 978
 979         local_save_flags(irq_flags);
 980         pc = preempt_count();
 981
 982         dsize = __get_data_size(&tk->tp, regs);
 983         size = sizeof(*entry) + tk->tp.size + dsize;
 984
 985         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
 986                                                 call->event.type,
 987                                                 size, irq_flags, pc);
 988         if (!event)
 989                 return;
 990
 991         entry = ring_buffer_event_data(event);
 992         entry->func = (unsigned long)tk->rp.kp.addr;
 993         entry->ret_ip = (unsigned long)ri->ret_addr;
 994         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
 995
 996         event_trigger_unlock_commit_regs(trace_file, buffer, event,
 997                                          entry, irq_flags, pc, regs);
 998 }
 999
1000 static void
1001 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1002                      struct pt_regs *regs)
1003 {
1004         struct event_file_link *link;
1005
1006         list_for_each_entry_rcu(link, &tk->tp.files, list)
1007                 __kretprobe_trace_func(tk, ri, regs, link->file);
1008 }
1009 NOKPROBE_SYMBOL(kretprobe_trace_func);
1010
1011 /* Event entry printers */
1012 static enum print_line_t
1013 print_kprobe_event(struct trace_iterator *iter, int flags,
1014                    struct trace_event *event)
1015 {
1016         struct kprobe_trace_entry_head *field;
1017         struct trace_seq *s = &iter->seq;
1018         struct trace_probe *tp;
1019         u8 *data;
1020         int i;
1021
1022         field = (struct kprobe_trace_entry_head *)iter->ent;
1023         tp = container_of(event, struct trace_probe, call.event);
1024
1025         trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1026
1027         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1028                 goto out;
1029
1030         trace_seq_putc(s, ')');
1031
1032         data = (u8 *)&field[1];
1033         for (i = 0; i < tp->nr_args; i++)
1034                 if (!tp->args[i].type->print(s, tp->args[i].name,
1035                                              data + tp->args[i].offset, field))
1036                         goto out;
1037
1038         trace_seq_putc(s, '\n');
1039  out:
1040         return trace_handle_return(s);
1041 }
1042
1043 static enum print_line_t
1044 print_kretprobe_event(struct trace_iterator *iter, int flags,
1045                       struct trace_event *event)
1046 {
1047         struct kretprobe_trace_entry_head *field;
1048         struct trace_seq *s = &iter->seq;
1049         struct trace_probe *tp;
1050         u8 *data;
1051         int i;
1052
1053         field = (struct kretprobe_trace_entry_head *)iter->ent;
1054         tp = container_of(event, struct trace_probe, call.event);
1055
1056         trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1057
1058         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1059                 goto out;
1060
1061         trace_seq_puts(s, " <- ");
1062
1063         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1064                 goto out;
1065
1066         trace_seq_putc(s, ')');
1067
1068         data = (u8 *)&field[1];
1069         for (i = 0; i < tp->nr_args; i++)
1070                 if (!tp->args[i].type->print(s, tp->args[i].name,
1071                                              data + tp->args[i].offset, field))
1072                         goto out;
1073
1074         trace_seq_putc(s, '\n');
1075
1076  out:
1077         return trace_handle_return(s);
1078 }
1079
1080
1081 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1082 {
1083         int ret, i;
1084         struct kprobe_trace_entry_head field;
1085         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1086
1087         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1088         /* Set argument names as fields */
1089         for (i = 0; i < tk->tp.nr_args; i++) {
1090                 struct probe_arg *parg = &tk->tp.args[i];
1091
1092                 ret = trace_define_field(event_call, parg->type->fmttype,
1093                                          parg->name,
1094                                          sizeof(field) + parg->offset,
1095                                          parg->type->size,
1096                                          parg->type->is_signed,
1097                                          FILTER_OTHER);
1098                 if (ret)
1099                         return ret;
1100         }
1101         return 0;
1102 }
1103
1104 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1105 {
1106         int ret, i;
1107         struct kretprobe_trace_entry_head field;
1108         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1109
1110         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1111         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1112         /* Set argument names as fields */
1113         for (i = 0; i < tk->tp.nr_args; i++) {
1114                 struct probe_arg *parg = &tk->tp.args[i];
1115
1116                 ret = trace_define_field(event_call, parg->type->fmttype,
1117                                          parg->name,
1118                                          sizeof(field) + parg->offset,
1119                                          parg->type->size,
1120                                          parg->type->is_signed,
1121                                          FILTER_OTHER);
1122                 if (ret)
1123                         return ret;
1124         }
1125         return 0;
1126 }
1127
1128 #ifdef CONFIG_PERF_EVENTS
1129
1130 /* Kprobe profile handler */
1131 static void
1132 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1133 {
1134         struct trace_event_call *call = &tk->tp.call;
1135         struct bpf_prog *prog = call->prog;
1136         struct kprobe_trace_entry_head *entry;
1137         struct hlist_head *head;
1138         int size, __size, dsize;
1139         int rctx;
1140
1141         if (prog && !trace_call_bpf(prog, regs))
1142                 return;
1143
1144         head = this_cpu_ptr(call->perf_events);
1145         if (hlist_empty(head))
1146                 return;
1147
1148         dsize = __get_data_size(&tk->tp, regs);
1149         __size = sizeof(*entry) + tk->tp.size + dsize;
1150         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1151         size -= sizeof(u32);
1152
1153         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1154         if (!entry)
1155                 return;
1156
1157         entry->ip = (unsigned long)tk->rp.kp.addr;
1158         memset(&entry[1], 0, dsize);
1159         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1160         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1161                               head, NULL);
1162 }
1163 NOKPROBE_SYMBOL(kprobe_perf_func);
1164
1165 /* Kretprobe profile handler */
1166 static void
1167 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1168                     struct pt_regs *regs)
1169 {
1170         struct trace_event_call *call = &tk->tp.call;
1171         struct bpf_prog *prog = call->prog;
1172         struct kretprobe_trace_entry_head *entry;
1173         struct hlist_head *head;
1174         int size, __size, dsize;
1175         int rctx;
1176
1177         if (prog && !trace_call_bpf(prog, regs))
1178                 return;
1179
1180         head = this_cpu_ptr(call->perf_events);
1181         if (hlist_empty(head))
1182                 return;
1183
1184         dsize = __get_data_size(&tk->tp, regs);
1185         __size = sizeof(*entry) + tk->tp.size + dsize;
1186         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1187         size -= sizeof(u32);
1188
1189         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1190         if (!entry)
1191                 return;
1192
1193         entry->func = (unsigned long)tk->rp.kp.addr;
1194         entry->ret_ip = (unsigned long)ri->ret_addr;
1195         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1196         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1197                               head, NULL);
1198 }
1199 NOKPROBE_SYMBOL(kretprobe_perf_func);
1200 #endif  /* CONFIG_PERF_EVENTS */
1201
1202 /*
1203  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1204  *
1205  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1206  * lockless, but we can't race with this __init function.
1207  */
1208 static int kprobe_register(struct trace_event_call *event,
1209                            enum trace_reg type, void *data)
1210 {
1211         struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1212         struct trace_event_file *file = data;
1213
1214         switch (type) {
1215         case TRACE_REG_REGISTER:
1216                 return enable_trace_kprobe(tk, file);
1217         case TRACE_REG_UNREGISTER:
1218                 return disable_trace_kprobe(tk, file);
1219
1220 #ifdef CONFIG_PERF_EVENTS
1221         case TRACE_REG_PERF_REGISTER:
1222                 return enable_trace_kprobe(tk, NULL);
1223         case TRACE_REG_PERF_UNREGISTER:
1224                 return disable_trace_kprobe(tk, NULL);
1225         case TRACE_REG_PERF_OPEN:
1226         case TRACE_REG_PERF_CLOSE:
1227         case TRACE_REG_PERF_ADD:
1228         case TRACE_REG_PERF_DEL:
1229                 return 0;
1230 #endif
1231         }
1232         return 0;
1233 }
1234
1235 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1236 {
1237         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1238
1239         raw_cpu_inc(*tk->nhit);
1240
1241         if (tk->tp.flags & TP_FLAG_TRACE)
1242                 kprobe_trace_func(tk, regs);
1243 #ifdef CONFIG_PERF_EVENTS
1244         if (tk->tp.flags & TP_FLAG_PROFILE)
1245                 kprobe_perf_func(tk, regs);
1246 #endif
1247         return 0;       /* We don't tweek kernel, so just return 0 */
1248 }
1249 NOKPROBE_SYMBOL(kprobe_dispatcher);
1250
1251 static int
1252 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1253 {
1254         struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1255
1256         raw_cpu_inc(*tk->nhit);
1257
1258         if (tk->tp.flags & TP_FLAG_TRACE)
1259                 kretprobe_trace_func(tk, ri, regs);
1260 #ifdef CONFIG_PERF_EVENTS
1261         if (tk->tp.flags & TP_FLAG_PROFILE)
1262                 kretprobe_perf_func(tk, ri, regs);
1263 #endif
1264         return 0;       /* We don't tweek kernel, so just return 0 */
1265 }
1266 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1267
1268 static struct trace_event_functions kretprobe_funcs = {
1269         .trace          = print_kretprobe_event
1270 };
1271
1272 static struct trace_event_functions kprobe_funcs = {
1273         .trace          = print_kprobe_event
1274 };
1275
1276 static int register_kprobe_event(struct trace_kprobe *tk)
1277 {
1278         struct trace_event_call *call = &tk->tp.call;
1279         int ret;
1280
1281         /* Initialize trace_event_call */
1282         INIT_LIST_HEAD(&call->class->fields);
1283         if (trace_kprobe_is_return(tk)) {
1284                 call->event.funcs = &kretprobe_funcs;
1285                 call->class->define_fields = kretprobe_event_define_fields;
1286         } else {
1287                 call->event.funcs = &kprobe_funcs;
1288                 call->class->define_fields = kprobe_event_define_fields;
1289         }
1290         if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1291                 return -ENOMEM;
1292         ret = register_trace_event(&call->event);
1293         if (!ret) {
1294                 kfree(call->print_fmt);
1295                 return -ENODEV;
1296         }
1297         call->flags = TRACE_EVENT_FL_KPROBE;
1298         call->class->reg = kprobe_register;
1299         call->data = tk;
1300         ret = trace_add_event_call(call);
1301         if (ret) {
1302                 pr_info("Failed to register kprobe event: %s\n",
1303                         trace_event_name(call));
1304                 kfree(call->print_fmt);
1305                 unregister_trace_event(&call->event);
1306         }
1307         return ret;
1308 }
1309
1310 static int unregister_kprobe_event(struct trace_kprobe *tk)
1311 {
1312         int ret;
1313
1314         /* tp->event is unregistered in trace_remove_event_call() */
1315         ret = trace_remove_event_call(&tk->tp.call);
1316         if (!ret)
1317                 kfree(tk->tp.call.print_fmt);
1318         return ret;
1319 }
1320
1321 /* Make a tracefs interface for controlling probe points */
1322 static __init int init_kprobe_trace(void)
1323 {
1324         struct dentry *d_tracer;
1325         struct dentry *entry;
1326
1327         if (register_module_notifier(&trace_kprobe_module_nb))
1328                 return -EINVAL;
1329
1330         d_tracer = tracing_init_dentry();
1331         if (IS_ERR(d_tracer))
1332                 return 0;
1333
1334         entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1335                                     NULL, &kprobe_events_ops);
1336
1337         /* Event list interface */
1338         if (!entry)
1339                 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1340
1341         /* Profile interface */
1342         entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1343                                     NULL, &kprobe_profile_ops);
1344
1345         if (!entry)
1346                 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1347         return 0;
1348 }
1349 fs_initcall(init_kprobe_trace);
1350
1351
1352 #ifdef CONFIG_FTRACE_STARTUP_TEST
1353
1354 /*
1355  * The "__used" keeps gcc from removing the function symbol
1356  * from the kallsyms table.
1357  */
1358 static __used int kprobe_trace_selftest_target(int a1, int a2, int a3,
1359                                                int a4, int a5, int a6)
1360 {
1361         return a1 + a2 + a3 + a4 + a5 + a6;
1362 }
1363
1364 static struct trace_event_file *
1365 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1366 {
1367         struct trace_event_file *file;
1368
1369         list_for_each_entry(file, &tr->events, list)
1370                 if (file->event_call == &tk->tp.call)
1371                         return file;
1372
1373         return NULL;
1374 }
1375
1376 /*
1377  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1378  * stage, we can do this lockless.
1379  */
1380 static __init int kprobe_trace_self_tests_init(void)
1381 {
1382         int ret, warn = 0;
1383         int (*target)(int, int, int, int, int, int);
1384         struct trace_kprobe *tk;
1385         struct trace_event_file *file;
1386
1387         if (tracing_is_disabled())
1388                 return -ENODEV;
1389
1390         target = kprobe_trace_selftest_target;
1391
1392         pr_info("Testing kprobe tracing: ");
1393
1394         ret = traceprobe_command("p:testprobe kprobe_trace_selftest_target "
1395                                   "$stack $stack0 +0($stack)",
1396                                   create_trace_kprobe);
1397         if (WARN_ON_ONCE(ret)) {
1398                 pr_warn("error on probing function entry.\n");
1399                 warn++;
1400         } else {
1401                 /* Enable trace point */
1402                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1403                 if (WARN_ON_ONCE(tk == NULL)) {
1404                         pr_warn("error on getting new probe.\n");
1405                         warn++;
1406                 } else {
1407                         file = find_trace_probe_file(tk, top_trace_array());
1408                         if (WARN_ON_ONCE(file == NULL)) {
1409                                 pr_warn("error on getting probe file.\n");
1410                                 warn++;
1411                         } else
1412                                 enable_trace_kprobe(tk, file);
1413                 }
1414         }
1415
1416         ret = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target "
1417                                   "$retval", create_trace_kprobe);
1418         if (WARN_ON_ONCE(ret)) {
1419                 pr_warn("error on probing function return.\n");
1420                 warn++;
1421         } else {
1422                 /* Enable trace point */
1423                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1424                 if (WARN_ON_ONCE(tk == NULL)) {
1425                         pr_warn("error on getting 2nd new probe.\n");
1426                         warn++;
1427                 } else {
1428                         file = find_trace_probe_file(tk, top_trace_array());
1429                         if (WARN_ON_ONCE(file == NULL)) {
1430                                 pr_warn("error on getting probe file.\n");
1431                                 warn++;
1432                         } else
1433                                 enable_trace_kprobe(tk, file);
1434                 }
1435         }
1436
1437         if (warn)
1438                 goto end;
1439
1440         ret = target(1, 2, 3, 4, 5, 6);
1441
1442         /* Disable trace points before removing it */
1443         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1444         if (WARN_ON_ONCE(tk == NULL)) {
1445                 pr_warn("error on getting test probe.\n");
1446                 warn++;
1447         } else {
1448                 file = find_trace_probe_file(tk, top_trace_array());
1449                 if (WARN_ON_ONCE(file == NULL)) {
1450                         pr_warn("error on getting probe file.\n");
1451                         warn++;
1452                 } else
1453                         disable_trace_kprobe(tk, file);
1454         }
1455
1456         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1457         if (WARN_ON_ONCE(tk == NULL)) {
1458                 pr_warn("error on getting 2nd test probe.\n");
1459                 warn++;
1460         } else {
1461                 file = find_trace_probe_file(tk, top_trace_array());
1462                 if (WARN_ON_ONCE(file == NULL)) {
1463                         pr_warn("error on getting probe file.\n");
1464                         warn++;
1465                 } else
1466                         disable_trace_kprobe(tk, file);
1467         }
1468
1469         ret = traceprobe_command("-:testprobe", create_trace_kprobe);
1470         if (WARN_ON_ONCE(ret)) {
1471                 pr_warn("error on deleting a probe.\n");
1472                 warn++;
1473         }
1474
1475         ret = traceprobe_command("-:testprobe2", create_trace_kprobe);
1476         if (WARN_ON_ONCE(ret)) {
1477                 pr_warn("error on deleting a probe.\n");
1478                 warn++;
1479         }
1480
1481 end:
1482         release_all_trace_kprobes();
1483         if (warn)
1484                 pr_cont("NG: Some tests are failed. Please check them.\n");
1485         else
1486                 pr_cont("OK\n");
1487         return 0;
1488 }
1489
1490 late_initcall(kprobe_trace_self_tests_init);
1491
1492 #endif