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         ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),
 257         ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
 258         ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
 259         ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
 260
 261         ASSIGN_FETCH_TYPE_END
 262 };
 263
 264 /*
 265  * Allocate new trace_probe and initialize it (including kprobes).
 266  */
 267 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
 268                                              const char *event,
 269                                              void *addr,
 270                                              const char *symbol,
 271                                              unsigned long offs,
 272                                              int nargs, bool is_return)
 273 {
 274         struct trace_kprobe *tk;
 275         int ret = -ENOMEM;
 276
 277         tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
 278         if (!tk)
 279                 return ERR_PTR(ret);
 280
 281         tk->nhit = alloc_percpu(unsigned long);
 282         if (!tk->nhit)
 283                 goto error;
 284
 285         if (symbol) {
 286                 tk->symbol = kstrdup(symbol, GFP_KERNEL);
 287                 if (!tk->symbol)
 288                         goto error;
 289                 tk->rp.kp.symbol_name = tk->symbol;
 290                 tk->rp.kp.offset = offs;
 291         } else
 292                 tk->rp.kp.addr = addr;
 293
 294         if (is_return)
 295                 tk->rp.handler = kretprobe_dispatcher;
 296         else
 297                 tk->rp.kp.pre_handler = kprobe_dispatcher;
 298
 299         if (!event || !is_good_name(event)) {
 300                 ret = -EINVAL;
 301                 goto error;
 302         }
 303
 304         tk->tp.call.class = &tk->tp.class;
 305         tk->tp.call.name = kstrdup(event, GFP_KERNEL);
 306         if (!tk->tp.call.name)
 307                 goto error;
 308
 309         if (!group || !is_good_name(group)) {
 310                 ret = -EINVAL;
 311                 goto error;
 312         }
 313
 314         tk->tp.class.system = kstrdup(group, GFP_KERNEL);
 315         if (!tk->tp.class.system)
 316                 goto error;
 317
 318         INIT_LIST_HEAD(&tk->list);
 319         INIT_LIST_HEAD(&tk->tp.files);
 320         return tk;
 321 error:
 322         kfree(tk->tp.call.name);
 323         kfree(tk->symbol);
 324         free_percpu(tk->nhit);
 325         kfree(tk);
 326         return ERR_PTR(ret);
 327 }
 328
 329 static void free_trace_kprobe(struct trace_kprobe *tk)
 330 {
 331         int i;
 332
 333         for (i = 0; i < tk->tp.nr_args; i++)
 334                 traceprobe_free_probe_arg(&tk->tp.args[i]);
 335
 336         kfree(tk->tp.call.class->system);
 337         kfree(tk->tp.call.name);
 338         kfree(tk->symbol);
 339         free_percpu(tk->nhit);
 340         kfree(tk);
 341 }
 342
 343 static struct trace_kprobe *find_trace_kprobe(const char *event,
 344                                               const char *group)
 345 {
 346         struct trace_kprobe *tk;
 347
 348         list_for_each_entry(tk, &probe_list, list)
 349                 if (strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
 350                     strcmp(tk->tp.call.class->system, group) == 0)
 351                         return tk;
 352         return NULL;
 353 }
 354
 355 /*
 356  * Enable trace_probe
 357  * if the file is NULL, enable "perf" handler, or enable "trace" handler.
 358  */
 359 static int
 360 enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
 361 {
 362         int ret = 0;
 363
 364         if (file) {
 365                 struct event_file_link *link;
 366
 367                 link = kmalloc(sizeof(*link), GFP_KERNEL);
 368                 if (!link) {
 369                         ret = -ENOMEM;
 370                         goto out;
 371                 }
 372
 373                 link->file = file;
 374                 list_add_tail_rcu(&link->list, &tk->tp.files);
 375
 376                 tk->tp.flags |= TP_FLAG_TRACE;
 377         } else
 378                 tk->tp.flags |= TP_FLAG_PROFILE;
 379
 380         if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
 381                 if (trace_kprobe_is_return(tk))
 382                         ret = enable_kretprobe(&tk->rp);
 383                 else
 384                         ret = enable_kprobe(&tk->rp.kp);
 385         }
 386  out:
 387         return ret;
 388 }
 389
 390 /*
 391  * Disable trace_probe
 392  * if the file is NULL, disable "perf" handler, or disable "trace" handler.
 393  */
 394 static int
 395 disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
 396 {
 397         struct event_file_link *link = NULL;
 398         int wait = 0;
 399         int ret = 0;
 400
 401         if (file) {
 402                 link = find_event_file_link(&tk->tp, file);
 403                 if (!link) {
 404                         ret = -EINVAL;
 405                         goto out;
 406                 }
 407
 408                 list_del_rcu(&link->list);
 409                 wait = 1;
 410                 if (!list_empty(&tk->tp.files))
 411                         goto out;
 412
 413                 tk->tp.flags &= ~TP_FLAG_TRACE;
 414         } else
 415                 tk->tp.flags &= ~TP_FLAG_PROFILE;
 416
 417         if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
 418                 if (trace_kprobe_is_return(tk))
 419                         disable_kretprobe(&tk->rp);
 420                 else
 421                         disable_kprobe(&tk->rp.kp);
 422                 wait = 1;
 423         }
 424  out:
 425         if (wait) {
 426                 /*
 427                  * Synchronize with kprobe_trace_func/kretprobe_trace_func
 428                  * to ensure disabled (all running handlers are finished).
 429                  * This is not only for kfree(), but also the caller,
 430                  * trace_remove_event_call() supposes it for releasing
 431                  * event_call related objects, which will be accessed in
 432                  * the kprobe_trace_func/kretprobe_trace_func.
 433                  */
 434                 synchronize_sched();
 435                 kfree(link);    /* Ignored if link == NULL */
 436         }
 437
 438         return ret;
 439 }
 440
 441 /* Internal register function - just handle k*probes and flags */
 442 static int __register_trace_kprobe(struct trace_kprobe *tk)
 443 {
 444         int i, ret;
 445
 446         if (trace_probe_is_registered(&tk->tp))
 447                 return -EINVAL;
 448
 449         for (i = 0; i < tk->tp.nr_args; i++)
 450                 traceprobe_update_arg(&tk->tp.args[i]);
 451
 452         /* Set/clear disabled flag according to tp->flag */
 453         if (trace_probe_is_enabled(&tk->tp))
 454                 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
 455         else
 456                 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 457
 458         if (trace_kprobe_is_return(tk))
 459                 ret = register_kretprobe(&tk->rp);
 460         else
 461                 ret = register_kprobe(&tk->rp.kp);
 462
 463         if (ret == 0)
 464                 tk->tp.flags |= TP_FLAG_REGISTERED;
 465         else {
 466                 pr_warn("Could not insert probe at %s+%lu: %d\n",
 467                         trace_kprobe_symbol(tk), trace_kprobe_offset(tk), ret);
 468                 if (ret == -ENOENT && trace_kprobe_is_on_module(tk)) {
 469                         pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
 470                         ret = 0;
 471                 } else if (ret == -EILSEQ) {
 472                         pr_warn("Probing address(0x%p) is not an instruction boundary.\n",
 473                                 tk->rp.kp.addr);
 474                         ret = -EINVAL;
 475                 }
 476         }
 477
 478         return ret;
 479 }
 480
 481 /* Internal unregister function - just handle k*probes and flags */
 482 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
 483 {
 484         if (trace_probe_is_registered(&tk->tp)) {
 485                 if (trace_kprobe_is_return(tk))
 486                         unregister_kretprobe(&tk->rp);
 487                 else
 488                         unregister_kprobe(&tk->rp.kp);
 489                 tk->tp.flags &= ~TP_FLAG_REGISTERED;
 490                 /* Cleanup kprobe for reuse */
 491                 if (tk->rp.kp.symbol_name)
 492                         tk->rp.kp.addr = NULL;
 493         }
 494 }
 495
 496 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
 497 static int unregister_trace_kprobe(struct trace_kprobe *tk)
 498 {
 499         /* Enabled event can not be unregistered */
 500         if (trace_probe_is_enabled(&tk->tp))
 501                 return -EBUSY;
 502
 503         /* Will fail if probe is being used by ftrace or perf */
 504         if (unregister_kprobe_event(tk))
 505                 return -EBUSY;
 506
 507         __unregister_trace_kprobe(tk);
 508         list_del(&tk->list);
 509
 510         return 0;
 511 }
 512
 513 /* Register a trace_probe and probe_event */
 514 static int register_trace_kprobe(struct trace_kprobe *tk)
 515 {
 516         struct trace_kprobe *old_tk;
 517         int ret;
 518
 519         mutex_lock(&probe_lock);
 520
 521         /* Delete old (same name) event if exist */
 522         old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call),
 523                         tk->tp.call.class->system);
 524         if (old_tk) {
 525                 ret = unregister_trace_kprobe(old_tk);
 526                 if (ret < 0)
 527                         goto end;
 528                 free_trace_kprobe(old_tk);
 529         }
 530
 531         /* Register new event */
 532         ret = register_kprobe_event(tk);
 533         if (ret) {
 534                 pr_warn("Failed to register probe event(%d)\n", ret);
 535                 goto end;
 536         }
 537
 538         /* Register k*probe */
 539         ret = __register_trace_kprobe(tk);
 540         if (ret < 0)
 541                 unregister_kprobe_event(tk);
 542         else
 543                 list_add_tail(&tk->list, &probe_list);
 544
 545 end:
 546         mutex_unlock(&probe_lock);
 547         return ret;
 548 }
 549
 550 /* Module notifier call back, checking event on the module */
 551 static int trace_kprobe_module_callback(struct notifier_block *nb,
 552                                        unsigned long val, void *data)
 553 {
 554         struct module *mod = data;
 555         struct trace_kprobe *tk;
 556         int ret;
 557
 558         if (val != MODULE_STATE_COMING)
 559                 return NOTIFY_DONE;
 560
 561         /* Update probes on coming module */
 562         mutex_lock(&probe_lock);
 563         list_for_each_entry(tk, &probe_list, list) {
 564                 if (trace_kprobe_within_module(tk, mod)) {
 565                         /* Don't need to check busy - this should have gone. */
 566                         __unregister_trace_kprobe(tk);
 567                         ret = __register_trace_kprobe(tk);
 568                         if (ret)
 569                                 pr_warn("Failed to re-register probe %s on %s: %d\n",
 570                                         trace_event_name(&tk->tp.call),
 571                                         mod->name, ret);
 572                 }
 573         }
 574         mutex_unlock(&probe_lock);
 575
 576         return NOTIFY_DONE;
 577 }
 578
 579 static struct notifier_block trace_kprobe_module_nb = {
 580         .notifier_call = trace_kprobe_module_callback,
 581         .priority = 1   /* Invoked after kprobe module callback */
 582 };
 583
 584 static int create_trace_kprobe(int argc, char **argv)
 585 {
 586         /*
 587          * Argument syntax:
 588          *  - Add kprobe: p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
 589          *  - Add kretprobe: r[:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
 590          * Fetch args:
 591          *  $retval     : fetch return value
 592          *  $stack      : fetch stack address
 593          *  $stackN     : fetch Nth of stack (N:0-)
 594          *  $comm       : fetch current task comm
 595          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 596          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 597          *  %REG        : fetch register REG
 598          * Dereferencing memory fetch:
 599          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 600          * Alias name of args:
 601          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 602          * Type of args:
 603          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 604          */
 605         struct trace_kprobe *tk;
 606         int i, ret = 0;
 607         bool is_return = false, is_delete = false;
 608         char *symbol = NULL, *event = NULL, *group = NULL;
 609         char *arg;
 610         unsigned long offset = 0;
 611         void *addr = NULL;
 612         char buf[MAX_EVENT_NAME_LEN];
 613
 614         /* argc must be >= 1 */
 615         if (argv[0][0] == 'p')
 616                 is_return = false;
 617         else if (argv[0][0] == 'r')
 618                 is_return = true;
 619         else if (argv[0][0] == '-')
 620                 is_delete = true;
 621         else {
 622                 pr_info("Probe definition must be started with 'p', 'r' or"
 623                         " '-'.\n");
 624                 return -EINVAL;
 625         }
 626
 627         if (argv[0][1] == ':') {
 628                 event = &argv[0][2];
 629                 if (strchr(event, '/')) {
 630                         group = event;
 631                         event = strchr(group, '/') + 1;
 632                         event[-1] = '\0';
 633                         if (strlen(group) == 0) {
 634                                 pr_info("Group name is not specified\n");
 635                                 return -EINVAL;
 636                         }
 637                 }
 638                 if (strlen(event) == 0) {
 639                         pr_info("Event name is not specified\n");
 640                         return -EINVAL;
 641                 }
 642         }
 643         if (!group)
 644                 group = KPROBE_EVENT_SYSTEM;
 645
 646         if (is_delete) {
 647                 if (!event) {
 648                         pr_info("Delete command needs an event name.\n");
 649                         return -EINVAL;
 650                 }
 651                 mutex_lock(&probe_lock);
 652                 tk = find_trace_kprobe(event, group);
 653                 if (!tk) {
 654                         mutex_unlock(&probe_lock);
 655                         pr_info("Event %s/%s doesn't exist.\n", group, event);
 656                         return -ENOENT;
 657                 }
 658                 /* delete an event */
 659                 ret = unregister_trace_kprobe(tk);
 660                 if (ret == 0)
 661                         free_trace_kprobe(tk);
 662                 mutex_unlock(&probe_lock);
 663                 return ret;
 664         }
 665
 666         if (argc < 2) {
 667                 pr_info("Probe point is not specified.\n");
 668                 return -EINVAL;
 669         }
 670         if (isdigit(argv[1][0])) {
 671                 if (is_return) {
 672                         pr_info("Return probe point must be a symbol.\n");
 673                         return -EINVAL;
 674                 }
 675                 /* an address specified */
 676                 ret = kstrtoul(&argv[1][0], 0, (unsigned long *)&addr);
 677                 if (ret) {
 678                         pr_info("Failed to parse address.\n");
 679                         return ret;
 680                 }
 681         } else {
 682                 /* a symbol specified */
 683                 symbol = argv[1];
 684                 /* TODO: support .init module functions */
 685                 ret = traceprobe_split_symbol_offset(symbol, &offset);
 686                 if (ret) {
 687                         pr_info("Failed to parse symbol.\n");
 688                         return ret;
 689                 }
 690                 if (offset && is_return) {
 691                         pr_info("Return probe must be used without offset.\n");
 692                         return -EINVAL;
 693                 }
 694         }
 695         argc -= 2; argv += 2;
 696
 697         /* setup a probe */
 698         if (!event) {
 699                 /* Make a new event name */
 700                 if (symbol)
 701                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 702                                  is_return ? 'r' : 'p', symbol, offset);
 703                 else
 704                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 705                                  is_return ? 'r' : 'p', addr);
 706                 event = buf;
 707         }
 708         tk = alloc_trace_kprobe(group, event, addr, symbol, offset, argc,
 709                                is_return);
 710         if (IS_ERR(tk)) {
 711                 pr_info("Failed to allocate trace_probe.(%d)\n",
 712                         (int)PTR_ERR(tk));
 713                 return PTR_ERR(tk);
 714         }
 715
 716         /* parse arguments */
 717         ret = 0;
 718         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 719                 struct probe_arg *parg = &tk->tp.args[i];
 720
 721                 /* Increment count for freeing args in error case */
 722                 tk->tp.nr_args++;
 723
 724                 /* Parse argument name */
 725                 arg = strchr(argv[i], '=');
 726                 if (arg) {
 727                         *arg++ = '\0';
 728                         parg->name = kstrdup(argv[i], GFP_KERNEL);
 729                 } else {
 730                         arg = argv[i];
 731                         /* If argument name is omitted, set "argN" */
 732                         snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
 733                         parg->name = kstrdup(buf, GFP_KERNEL);
 734                 }
 735
 736                 if (!parg->name) {
 737                         pr_info("Failed to allocate argument[%d] name.\n", i);
 738                         ret = -ENOMEM;
 739                         goto error;
 740                 }
 741
 742                 if (!is_good_name(parg->name)) {
 743                         pr_info("Invalid argument[%d] name: %s\n",
 744                                 i, parg->name);
 745                         ret = -EINVAL;
 746                         goto error;
 747                 }
 748
 749                 if (traceprobe_conflict_field_name(parg->name,
 750                                                         tk->tp.args, i)) {
 751                         pr_info("Argument[%d] name '%s' conflicts with "
 752                                 "another field.\n", i, argv[i]);
 753                         ret = -EINVAL;
 754                         goto error;
 755                 }
 756
 757                 /* Parse fetch argument */
 758                 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
 759                                                 is_return, true,
 760                                                 kprobes_fetch_type_table);
 761                 if (ret) {
 762                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
 763                         goto error;
 764                 }
 765         }
 766
 767         ret = register_trace_kprobe(tk);
 768         if (ret)
 769                 goto error;
 770         return 0;
 771
 772 error:
 773         free_trace_kprobe(tk);
 774         return ret;
 775 }
 776
 777 static int release_all_trace_kprobes(void)
 778 {
 779         struct trace_kprobe *tk;
 780         int ret = 0;
 781
 782         mutex_lock(&probe_lock);
 783         /* Ensure no probe is in use. */
 784         list_for_each_entry(tk, &probe_list, list)
 785                 if (trace_probe_is_enabled(&tk->tp)) {
 786                         ret = -EBUSY;
 787                         goto end;
 788                 }
 789         /* TODO: Use batch unregistration */
 790         while (!list_empty(&probe_list)) {
 791                 tk = list_entry(probe_list.next, struct trace_kprobe, list);
 792                 ret = unregister_trace_kprobe(tk);
 793                 if (ret)
 794                         goto end;
 795                 free_trace_kprobe(tk);
 796         }
 797
 798 end:
 799         mutex_unlock(&probe_lock);
 800
 801         return ret;
 802 }
 803
 804 /* Probes listing interfaces */
 805 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
 806 {
 807         mutex_lock(&probe_lock);
 808         return seq_list_start(&probe_list, *pos);
 809 }
 810
 811 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
 812 {
 813         return seq_list_next(v, &probe_list, pos);
 814 }
 815
 816 static void probes_seq_stop(struct seq_file *m, void *v)
 817 {
 818         mutex_unlock(&probe_lock);
 819 }
 820
 821 static int probes_seq_show(struct seq_file *m, void *v)
 822 {
 823         struct trace_kprobe *tk = v;
 824         int i;
 825
 826         seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
 827         seq_printf(m, ":%s/%s", tk->tp.call.class->system,
 828                         trace_event_name(&tk->tp.call));
 829
 830         if (!tk->symbol)
 831                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
 832         else if (tk->rp.kp.offset)
 833                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
 834                            tk->rp.kp.offset);
 835         else
 836                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
 837
 838         for (i = 0; i < tk->tp.nr_args; i++)
 839                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
 840         seq_putc(m, '\n');
 841
 842         return 0;
 843 }
 844
 845 static const struct seq_operations probes_seq_op = {
 846         .start  = probes_seq_start,
 847         .next   = probes_seq_next,
 848         .stop   = probes_seq_stop,
 849         .show   = probes_seq_show
 850 };
 851
 852 static int probes_open(struct inode *inode, struct file *file)
 853 {
 854         int ret;
 855
 856         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
 857                 ret = release_all_trace_kprobes();
 858                 if (ret < 0)
 859                         return ret;
 860         }
 861
 862         return seq_open(file, &probes_seq_op);
 863 }
 864
 865 static ssize_t probes_write(struct file *file, const char __user *buffer,
 866                             size_t count, loff_t *ppos)
 867 {
 868         return traceprobe_probes_write(file, buffer, count, ppos,
 869                         create_trace_kprobe);
 870 }
 871
 872 static const struct file_operations kprobe_events_ops = {
 873         .owner          = THIS_MODULE,
 874         .open           = probes_open,
 875         .read           = seq_read,
 876         .llseek         = seq_lseek,
 877         .release        = seq_release,
 878         .write          = probes_write,
 879 };
 880
 881 /* Probes profiling interfaces */
 882 static int probes_profile_seq_show(struct seq_file *m, void *v)
 883 {
 884         struct trace_kprobe *tk = v;
 885         unsigned long nhit = 0;
 886         int cpu;
 887
 888         for_each_possible_cpu(cpu)
 889                 nhit += *per_cpu_ptr(tk->nhit, cpu);
 890
 891         seq_printf(m, "  %-44s %15lu %15lu\n",
 892                    trace_event_name(&tk->tp.call), nhit,
 893                    tk->rp.kp.nmissed);
 894
 895         return 0;
 896 }
 897
 898 static const struct seq_operations profile_seq_op = {
 899         .start  = probes_seq_start,
 900         .next   = probes_seq_next,
 901         .stop   = probes_seq_stop,
 902         .show   = probes_profile_seq_show
 903 };
 904
 905 static int profile_open(struct inode *inode, struct file *file)
 906 {
 907         return seq_open(file, &profile_seq_op);
 908 }
 909
 910 static const struct file_operations kprobe_profile_ops = {
 911         .owner          = THIS_MODULE,
 912         .open           = profile_open,
 913         .read           = seq_read,
 914         .llseek         = seq_lseek,
 915         .release        = seq_release,
 916 };
 917
 918 /* Kprobe handler */
 919 static nokprobe_inline void
 920 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
 921                     struct trace_event_file *trace_file)
 922 {
 923         struct kprobe_trace_entry_head *entry;
 924         struct ring_buffer_event *event;
 925         struct ring_buffer *buffer;
 926         int size, dsize, pc;
 927         unsigned long irq_flags;
 928         struct trace_event_call *call = &tk->tp.call;
 929
 930         WARN_ON(call != trace_file->event_call);
 931
 932         if (trace_trigger_soft_disabled(trace_file))
 933                 return;
 934
 935         local_save_flags(irq_flags);
 936         pc = preempt_count();
 937
 938         dsize = __get_data_size(&tk->tp, regs);
 939         size = sizeof(*entry) + tk->tp.size + dsize;
 940
 941         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
 942                                                 call->event.type,
 943                                                 size, irq_flags, pc);
 944         if (!event)
 945                 return;
 946
 947         entry = ring_buffer_event_data(event);
 948         entry->ip = (unsigned long)tk->rp.kp.addr;
 949         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
 950
 951         event_trigger_unlock_commit_regs(trace_file, buffer, event,
 952                                          entry, irq_flags, pc, regs);
 953 }
 954
 955 static void
 956 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
 957 {
 958         struct event_file_link *link;
 959
 960         list_for_each_entry_rcu(link, &tk->tp.files, list)
 961                 __kprobe_trace_func(tk, regs, link->file);
 962 }
 963 NOKPROBE_SYMBOL(kprobe_trace_func);
 964
 965 /* Kretprobe handler */
 966 static nokprobe_inline void
 967 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
 968                        struct pt_regs *regs,
 969                        struct trace_event_file *trace_file)
 970 {
 971         struct kretprobe_trace_entry_head *entry;
 972         struct ring_buffer_event *event;
 973         struct ring_buffer *buffer;
 974         int size, pc, dsize;
 975         unsigned long irq_flags;
 976         struct trace_event_call *call = &tk->tp.call;
 977
 978         WARN_ON(call != trace_file->event_call);
 979
 980         if (trace_trigger_soft_disabled(trace_file))
 981                 return;
 982
 983         local_save_flags(irq_flags);
 984         pc = preempt_count();
 985
 986         dsize = __get_data_size(&tk->tp, regs);
 987         size = sizeof(*entry) + tk->tp.size + dsize;
 988
 989         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
 990                                                 call->event.type,
 991                                                 size, irq_flags, pc);
 992         if (!event)
 993                 return;
 994
 995         entry = ring_buffer_event_data(event);
 996         entry->func = (unsigned long)tk->rp.kp.addr;
 997         entry->ret_ip = (unsigned long)ri->ret_addr;
 998         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
 999
1000         event_trigger_unlock_commit_regs(trace_file, buffer, event,
1001                                          entry, irq_flags, pc, regs);
1002 }
1003
1004 static void
1005 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1006                      struct pt_regs *regs)
1007 {
1008         struct event_file_link *link;
1009
1010         list_for_each_entry_rcu(link, &tk->tp.files, list)
1011                 __kretprobe_trace_func(tk, ri, regs, link->file);
1012 }
1013 NOKPROBE_SYMBOL(kretprobe_trace_func);
1014
1015 /* Event entry printers */
1016 static enum print_line_t
1017 print_kprobe_event(struct trace_iterator *iter, int flags,
1018                    struct trace_event *event)
1019 {
1020         struct kprobe_trace_entry_head *field;
1021         struct trace_seq *s = &iter->seq;
1022         struct trace_probe *tp;
1023         u8 *data;
1024         int i;
1025
1026         field = (struct kprobe_trace_entry_head *)iter->ent;
1027         tp = container_of(event, struct trace_probe, call.event);
1028
1029         trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1030
1031         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1032                 goto out;
1033
1034         trace_seq_putc(s, ')');
1035
1036         data = (u8 *)&field[1];
1037         for (i = 0; i < tp->nr_args; i++)
1038                 if (!tp->args[i].type->print(s, tp->args[i].name,
1039                                              data + tp->args[i].offset, field))
1040                         goto out;
1041
1042         trace_seq_putc(s, '\n');
1043  out:
1044         return trace_handle_return(s);
1045 }
1046
1047 static enum print_line_t
1048 print_kretprobe_event(struct trace_iterator *iter, int flags,
1049                       struct trace_event *event)
1050 {
1051         struct kretprobe_trace_entry_head *field;
1052         struct trace_seq *s = &iter->seq;
1053         struct trace_probe *tp;
1054         u8 *data;
1055         int i;
1056
1057         field = (struct kretprobe_trace_entry_head *)iter->ent;
1058         tp = container_of(event, struct trace_probe, call.event);
1059
1060         trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1061
1062         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1063                 goto out;
1064
1065         trace_seq_puts(s, " <- ");
1066
1067         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1068                 goto out;
1069
1070         trace_seq_putc(s, ')');
1071
1072         data = (u8 *)&field[1];
1073         for (i = 0; i < tp->nr_args; i++)
1074                 if (!tp->args[i].type->print(s, tp->args[i].name,
1075                                              data + tp->args[i].offset, field))
1076                         goto out;
1077
1078         trace_seq_putc(s, '\n');
1079
1080  out:
1081         return trace_handle_return(s);
1082 }
1083
1084
1085 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1086 {
1087         int ret, i;
1088         struct kprobe_trace_entry_head field;
1089         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1090
1091         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1092         /* Set argument names as fields */
1093         for (i = 0; i < tk->tp.nr_args; i++) {
1094                 struct probe_arg *parg = &tk->tp.args[i];
1095
1096                 ret = trace_define_field(event_call, parg->type->fmttype,
1097                                          parg->name,
1098                                          sizeof(field) + parg->offset,
1099                                          parg->type->size,
1100                                          parg->type->is_signed,
1101                                          FILTER_OTHER);
1102                 if (ret)
1103                         return ret;
1104         }
1105         return 0;
1106 }
1107
1108 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1109 {
1110         int ret, i;
1111         struct kretprobe_trace_entry_head field;
1112         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1113
1114         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1115         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1116         /* Set argument names as fields */
1117         for (i = 0; i < tk->tp.nr_args; i++) {
1118                 struct probe_arg *parg = &tk->tp.args[i];
1119
1120                 ret = trace_define_field(event_call, parg->type->fmttype,
1121                                          parg->name,
1122                                          sizeof(field) + parg->offset,
1123                                          parg->type->size,
1124                                          parg->type->is_signed,
1125                                          FILTER_OTHER);
1126                 if (ret)
1127                         return ret;
1128         }
1129         return 0;
1130 }
1131
1132 #ifdef CONFIG_PERF_EVENTS
1133
1134 /* Kprobe profile handler */
1135 static void
1136 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1137 {
1138         struct trace_event_call *call = &tk->tp.call;
1139         struct bpf_prog *prog = call->prog;
1140         struct kprobe_trace_entry_head *entry;
1141         struct hlist_head *head;
1142         int size, __size, dsize;
1143         int rctx;
1144
1145         if (prog && !trace_call_bpf(prog, regs))
1146                 return;
1147
1148         head = this_cpu_ptr(call->perf_events);
1149         if (hlist_empty(head))
1150                 return;
1151
1152         dsize = __get_data_size(&tk->tp, regs);
1153         __size = sizeof(*entry) + tk->tp.size + dsize;
1154         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1155         size -= sizeof(u32);
1156
1157         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1158         if (!entry)
1159                 return;
1160
1161         entry->ip = (unsigned long)tk->rp.kp.addr;
1162         memset(&entry[1], 0, dsize);
1163         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1164         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1165                               head, NULL);
1166 }
1167 NOKPROBE_SYMBOL(kprobe_perf_func);
1168
1169 /* Kretprobe profile handler */
1170 static void
1171 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1172                     struct pt_regs *regs)
1173 {
1174         struct trace_event_call *call = &tk->tp.call;
1175         struct bpf_prog *prog = call->prog;
1176         struct kretprobe_trace_entry_head *entry;
1177         struct hlist_head *head;
1178         int size, __size, dsize;
1179         int rctx;
1180
1181         if (prog && !trace_call_bpf(prog, regs))
1182                 return;
1183
1184         head = this_cpu_ptr(call->perf_events);
1185         if (hlist_empty(head))
1186                 return;
1187
1188         dsize = __get_data_size(&tk->tp, regs);
1189         __size = sizeof(*entry) + tk->tp.size + dsize;
1190         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1191         size -= sizeof(u32);
1192
1193         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1194         if (!entry)
1195                 return;
1196
1197         entry->func = (unsigned long)tk->rp.kp.addr;
1198         entry->ret_ip = (unsigned long)ri->ret_addr;
1199         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1200         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1201                               head, NULL);
1202 }
1203 NOKPROBE_SYMBOL(kretprobe_perf_func);
1204 #endif  /* CONFIG_PERF_EVENTS */
1205
1206 /*
1207  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1208  *
1209  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1210  * lockless, but we can't race with this __init function.
1211  */
1212 static int kprobe_register(struct trace_event_call *event,
1213                            enum trace_reg type, void *data)
1214 {
1215         struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1216         struct trace_event_file *file = data;
1217
1218         switch (type) {
1219         case TRACE_REG_REGISTER:
1220                 return enable_trace_kprobe(tk, file);
1221         case TRACE_REG_UNREGISTER:
1222                 return disable_trace_kprobe(tk, file);
1223
1224 #ifdef CONFIG_PERF_EVENTS
1225         case TRACE_REG_PERF_REGISTER:
1226                 return enable_trace_kprobe(tk, NULL);
1227         case TRACE_REG_PERF_UNREGISTER:
1228                 return disable_trace_kprobe(tk, NULL);
1229         case TRACE_REG_PERF_OPEN:
1230         case TRACE_REG_PERF_CLOSE:
1231         case TRACE_REG_PERF_ADD:
1232         case TRACE_REG_PERF_DEL:
1233                 return 0;
1234 #endif
1235         }
1236         return 0;
1237 }
1238
1239 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1240 {
1241         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1242
1243         raw_cpu_inc(*tk->nhit);
1244
1245         if (tk->tp.flags & TP_FLAG_TRACE)
1246                 kprobe_trace_func(tk, regs);
1247 #ifdef CONFIG_PERF_EVENTS
1248         if (tk->tp.flags & TP_FLAG_PROFILE)
1249                 kprobe_perf_func(tk, regs);
1250 #endif
1251         return 0;       /* We don't tweek kernel, so just return 0 */
1252 }
1253 NOKPROBE_SYMBOL(kprobe_dispatcher);
1254
1255 static int
1256 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1257 {
1258         struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1259
1260         raw_cpu_inc(*tk->nhit);
1261
1262         if (tk->tp.flags & TP_FLAG_TRACE)
1263                 kretprobe_trace_func(tk, ri, regs);
1264 #ifdef CONFIG_PERF_EVENTS
1265         if (tk->tp.flags & TP_FLAG_PROFILE)
1266                 kretprobe_perf_func(tk, ri, regs);
1267 #endif
1268         return 0;       /* We don't tweek kernel, so just return 0 */
1269 }
1270 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1271
1272 static struct trace_event_functions kretprobe_funcs = {
1273         .trace          = print_kretprobe_event
1274 };
1275
1276 static struct trace_event_functions kprobe_funcs = {
1277         .trace          = print_kprobe_event
1278 };
1279
1280 static int register_kprobe_event(struct trace_kprobe *tk)
1281 {
1282         struct trace_event_call *call = &tk->tp.call;
1283         int ret;
1284
1285         /* Initialize trace_event_call */
1286         INIT_LIST_HEAD(&call->class->fields);
1287         if (trace_kprobe_is_return(tk)) {
1288                 call->event.funcs = &kretprobe_funcs;
1289                 call->class->define_fields = kretprobe_event_define_fields;
1290         } else {
1291                 call->event.funcs = &kprobe_funcs;
1292                 call->class->define_fields = kprobe_event_define_fields;
1293         }
1294         if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1295                 return -ENOMEM;
1296         ret = register_trace_event(&call->event);
1297         if (!ret) {
1298                 kfree(call->print_fmt);
1299                 return -ENODEV;
1300         }
1301         call->flags = TRACE_EVENT_FL_KPROBE;
1302         call->class->reg = kprobe_register;
1303         call->data = tk;
1304         ret = trace_add_event_call(call);
1305         if (ret) {
1306                 pr_info("Failed to register kprobe event: %s\n",
1307                         trace_event_name(call));
1308                 kfree(call->print_fmt);
1309                 unregister_trace_event(&call->event);
1310         }
1311         return ret;
1312 }
1313
1314 static int unregister_kprobe_event(struct trace_kprobe *tk)
1315 {
1316         int ret;
1317
1318         /* tp->event is unregistered in trace_remove_event_call() */
1319         ret = trace_remove_event_call(&tk->tp.call);
1320         if (!ret)
1321                 kfree(tk->tp.call.print_fmt);
1322         return ret;
1323 }
1324
1325 /* Make a tracefs interface for controlling probe points */
1326 static __init int init_kprobe_trace(void)
1327 {
1328         struct dentry *d_tracer;
1329         struct dentry *entry;
1330
1331         if (register_module_notifier(&trace_kprobe_module_nb))
1332                 return -EINVAL;
1333
1334         d_tracer = tracing_init_dentry();
1335         if (IS_ERR(d_tracer))
1336                 return 0;
1337
1338         entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1339                                     NULL, &kprobe_events_ops);
1340
1341         /* Event list interface */
1342         if (!entry)
1343                 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1344
1345         /* Profile interface */
1346         entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1347                                     NULL, &kprobe_profile_ops);
1348
1349         if (!entry)
1350                 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1351         return 0;
1352 }
1353 fs_initcall(init_kprobe_trace);
1354
1355
1356 #ifdef CONFIG_FTRACE_STARTUP_TEST
1357
1358 /*
1359  * The "__used" keeps gcc from removing the function symbol
1360  * from the kallsyms table.
1361  */
1362 static __used int kprobe_trace_selftest_target(int a1, int a2, int a3,
1363                                                int a4, int a5, int a6)
1364 {
1365         return a1 + a2 + a3 + a4 + a5 + a6;
1366 }
1367
1368 static struct trace_event_file *
1369 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1370 {
1371         struct trace_event_file *file;
1372
1373         list_for_each_entry(file, &tr->events, list)
1374                 if (file->event_call == &tk->tp.call)
1375                         return file;
1376
1377         return NULL;
1378 }
1379
1380 /*
1381  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1382  * stage, we can do this lockless.
1383  */
1384 static __init int kprobe_trace_self_tests_init(void)
1385 {
1386         int ret, warn = 0;
1387         int (*target)(int, int, int, int, int, int);
1388         struct trace_kprobe *tk;
1389         struct trace_event_file *file;
1390
1391         if (tracing_is_disabled())
1392                 return -ENODEV;
1393
1394         target = kprobe_trace_selftest_target;
1395
1396         pr_info("Testing kprobe tracing: ");
1397
1398         ret = traceprobe_command("p:testprobe kprobe_trace_selftest_target "
1399                                   "$stack $stack0 +0($stack)",
1400                                   create_trace_kprobe);
1401         if (WARN_ON_ONCE(ret)) {
1402                 pr_warn("error on probing function entry.\n");
1403                 warn++;
1404         } else {
1405                 /* Enable trace point */
1406                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1407                 if (WARN_ON_ONCE(tk == NULL)) {
1408                         pr_warn("error on getting new probe.\n");
1409                         warn++;
1410                 } else {
1411                         file = find_trace_probe_file(tk, top_trace_array());
1412                         if (WARN_ON_ONCE(file == NULL)) {
1413                                 pr_warn("error on getting probe file.\n");
1414                                 warn++;
1415                         } else
1416                                 enable_trace_kprobe(tk, file);
1417                 }
1418         }
1419
1420         ret = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target "
1421                                   "$retval", create_trace_kprobe);
1422         if (WARN_ON_ONCE(ret)) {
1423                 pr_warn("error on probing function return.\n");
1424                 warn++;
1425         } else {
1426                 /* Enable trace point */
1427                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1428                 if (WARN_ON_ONCE(tk == NULL)) {
1429                         pr_warn("error on getting 2nd new probe.\n");
1430                         warn++;
1431                 } else {
1432                         file = find_trace_probe_file(tk, top_trace_array());
1433                         if (WARN_ON_ONCE(file == NULL)) {
1434                                 pr_warn("error on getting probe file.\n");
1435                                 warn++;
1436                         } else
1437                                 enable_trace_kprobe(tk, file);
1438                 }
1439         }
1440
1441         if (warn)
1442                 goto end;
1443
1444         ret = target(1, 2, 3, 4, 5, 6);
1445
1446         /* Disable trace points before removing it */
1447         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1448         if (WARN_ON_ONCE(tk == NULL)) {
1449                 pr_warn("error on getting test probe.\n");
1450                 warn++;
1451         } else {
1452                 file = find_trace_probe_file(tk, top_trace_array());
1453                 if (WARN_ON_ONCE(file == NULL)) {
1454                         pr_warn("error on getting probe file.\n");
1455                         warn++;
1456                 } else
1457                         disable_trace_kprobe(tk, file);
1458         }
1459
1460         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1461         if (WARN_ON_ONCE(tk == NULL)) {
1462                 pr_warn("error on getting 2nd test probe.\n");
1463                 warn++;
1464         } else {
1465                 file = find_trace_probe_file(tk, top_trace_array());
1466                 if (WARN_ON_ONCE(file == NULL)) {
1467                         pr_warn("error on getting probe file.\n");
1468                         warn++;
1469                 } else
1470                         disable_trace_kprobe(tk, file);
1471         }
1472
1473         ret = traceprobe_command("-:testprobe", create_trace_kprobe);
1474         if (WARN_ON_ONCE(ret)) {
1475                 pr_warn("error on deleting a probe.\n");
1476                 warn++;
1477         }
1478
1479         ret = traceprobe_command("-:testprobe2", create_trace_kprobe);
1480         if (WARN_ON_ONCE(ret)) {
1481                 pr_warn("error on deleting a probe.\n");
1482                 warn++;
1483         }
1484
1485 end:
1486         release_all_trace_kprobes();
1487         if (warn)
1488                 pr_cont("NG: Some tests are failed. Please check them.\n");
1489         else
1490                 pr_cont("OK\n");
1491         return 0;
1492 }
1493
1494 late_initcall(kprobe_trace_self_tests_init);
1495
1496 #endif