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          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 591          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 592          *  %REG        : fetch register REG
 593          * Dereferencing memory fetch:
 594          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 595          * Alias name of args:
 596          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 597          * Type of args:
 598          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 599          */
 600         struct trace_kprobe *tk;
 601         int i, ret = 0;
 602         bool is_return = false, is_delete = false;
 603         char *symbol = NULL, *event = NULL, *group = NULL;
 604         char *arg;
 605         unsigned long offset = 0;
 606         void *addr = NULL;
 607         char buf[MAX_EVENT_NAME_LEN];
 608
 609         /* argc must be >= 1 */
 610         if (argv[0][0] == 'p')
 611                 is_return = false;
 612         else if (argv[0][0] == 'r')
 613                 is_return = true;
 614         else if (argv[0][0] == '-')
 615                 is_delete = true;
 616         else {
 617                 pr_info("Probe definition must be started with 'p', 'r' or"
 618                         " '-'.\n");
 619                 return -EINVAL;
 620         }
 621
 622         if (argv[0][1] == ':') {
 623                 event = &argv[0][2];
 624                 if (strchr(event, '/')) {
 625                         group = event;
 626                         event = strchr(group, '/') + 1;
 627                         event[-1] = '\0';
 628                         if (strlen(group) == 0) {
 629                                 pr_info("Group name is not specified\n");
 630                                 return -EINVAL;
 631                         }
 632                 }
 633                 if (strlen(event) == 0) {
 634                         pr_info("Event name is not specified\n");
 635                         return -EINVAL;
 636                 }
 637         }
 638         if (!group)
 639                 group = KPROBE_EVENT_SYSTEM;
 640
 641         if (is_delete) {
 642                 if (!event) {
 643                         pr_info("Delete command needs an event name.\n");
 644                         return -EINVAL;
 645                 }
 646                 mutex_lock(&probe_lock);
 647                 tk = find_trace_kprobe(event, group);
 648                 if (!tk) {
 649                         mutex_unlock(&probe_lock);
 650                         pr_info("Event %s/%s doesn't exist.\n", group, event);
 651                         return -ENOENT;
 652                 }
 653                 /* delete an event */
 654                 ret = unregister_trace_kprobe(tk);
 655                 if (ret == 0)
 656                         free_trace_kprobe(tk);
 657                 mutex_unlock(&probe_lock);
 658                 return ret;
 659         }
 660
 661         if (argc < 2) {
 662                 pr_info("Probe point is not specified.\n");
 663                 return -EINVAL;
 664         }
 665         if (isdigit(argv[1][0])) {
 666                 if (is_return) {
 667                         pr_info("Return probe point must be a symbol.\n");
 668                         return -EINVAL;
 669                 }
 670                 /* an address specified */
 671                 ret = kstrtoul(&argv[1][0], 0, (unsigned long *)&addr);
 672                 if (ret) {
 673                         pr_info("Failed to parse address.\n");
 674                         return ret;
 675                 }
 676         } else {
 677                 /* a symbol specified */
 678                 symbol = argv[1];
 679                 /* TODO: support .init module functions */
 680                 ret = traceprobe_split_symbol_offset(symbol, &offset);
 681                 if (ret) {
 682                         pr_info("Failed to parse symbol.\n");
 683                         return ret;
 684                 }
 685                 if (offset && is_return) {
 686                         pr_info("Return probe must be used without offset.\n");
 687                         return -EINVAL;
 688                 }
 689         }
 690         argc -= 2; argv += 2;
 691
 692         /* setup a probe */
 693         if (!event) {
 694                 /* Make a new event name */
 695                 if (symbol)
 696                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 697                                  is_return ? 'r' : 'p', symbol, offset);
 698                 else
 699                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 700                                  is_return ? 'r' : 'p', addr);
 701                 event = buf;
 702         }
 703         tk = alloc_trace_kprobe(group, event, addr, symbol, offset, argc,
 704                                is_return);
 705         if (IS_ERR(tk)) {
 706                 pr_info("Failed to allocate trace_probe.(%d)\n",
 707                         (int)PTR_ERR(tk));
 708                 return PTR_ERR(tk);
 709         }
 710
 711         /* parse arguments */
 712         ret = 0;
 713         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 714                 struct probe_arg *parg = &tk->tp.args[i];
 715
 716                 /* Increment count for freeing args in error case */
 717                 tk->tp.nr_args++;
 718
 719                 /* Parse argument name */
 720                 arg = strchr(argv[i], '=');
 721                 if (arg) {
 722                         *arg++ = '\0';
 723                         parg->name = kstrdup(argv[i], GFP_KERNEL);
 724                 } else {
 725                         arg = argv[i];
 726                         /* If argument name is omitted, set "argN" */
 727                         snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
 728                         parg->name = kstrdup(buf, GFP_KERNEL);
 729                 }
 730
 731                 if (!parg->name) {
 732                         pr_info("Failed to allocate argument[%d] name.\n", i);
 733                         ret = -ENOMEM;
 734                         goto error;
 735                 }
 736
 737                 if (!is_good_name(parg->name)) {
 738                         pr_info("Invalid argument[%d] name: %s\n",
 739                                 i, parg->name);
 740                         ret = -EINVAL;
 741                         goto error;
 742                 }
 743
 744                 if (traceprobe_conflict_field_name(parg->name,
 745                                                         tk->tp.args, i)) {
 746                         pr_info("Argument[%d] name '%s' conflicts with "
 747                                 "another field.\n", i, argv[i]);
 748                         ret = -EINVAL;
 749                         goto error;
 750                 }
 751
 752                 /* Parse fetch argument */
 753                 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
 754                                                 is_return, true,
 755                                                 kprobes_fetch_type_table);
 756                 if (ret) {
 757                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
 758                         goto error;
 759                 }
 760         }
 761
 762         ret = register_trace_kprobe(tk);
 763         if (ret)
 764                 goto error;
 765         return 0;
 766
 767 error:
 768         free_trace_kprobe(tk);
 769         return ret;
 770 }
 771
 772 static int release_all_trace_kprobes(void)
 773 {
 774         struct trace_kprobe *tk;
 775         int ret = 0;
 776
 777         mutex_lock(&probe_lock);
 778         /* Ensure no probe is in use. */
 779         list_for_each_entry(tk, &probe_list, list)
 780                 if (trace_probe_is_enabled(&tk->tp)) {
 781                         ret = -EBUSY;
 782                         goto end;
 783                 }
 784         /* TODO: Use batch unregistration */
 785         while (!list_empty(&probe_list)) {
 786                 tk = list_entry(probe_list.next, struct trace_kprobe, list);
 787                 ret = unregister_trace_kprobe(tk);
 788                 if (ret)
 789                         goto end;
 790                 free_trace_kprobe(tk);
 791         }
 792
 793 end:
 794         mutex_unlock(&probe_lock);
 795
 796         return ret;
 797 }
 798
 799 /* Probes listing interfaces */
 800 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
 801 {
 802         mutex_lock(&probe_lock);
 803         return seq_list_start(&probe_list, *pos);
 804 }
 805
 806 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
 807 {
 808         return seq_list_next(v, &probe_list, pos);
 809 }
 810
 811 static void probes_seq_stop(struct seq_file *m, void *v)
 812 {
 813         mutex_unlock(&probe_lock);
 814 }
 815
 816 static int probes_seq_show(struct seq_file *m, void *v)
 817 {
 818         struct trace_kprobe *tk = v;
 819         int i;
 820
 821         seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
 822         seq_printf(m, ":%s/%s", tk->tp.call.class->system,
 823                         trace_event_name(&tk->tp.call));
 824
 825         if (!tk->symbol)
 826                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
 827         else if (tk->rp.kp.offset)
 828                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
 829                            tk->rp.kp.offset);
 830         else
 831                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
 832
 833         for (i = 0; i < tk->tp.nr_args; i++)
 834                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
 835         seq_putc(m, '\n');
 836
 837         return 0;
 838 }
 839
 840 static const struct seq_operations probes_seq_op = {
 841         .start  = probes_seq_start,
 842         .next   = probes_seq_next,
 843         .stop   = probes_seq_stop,
 844         .show   = probes_seq_show
 845 };
 846
 847 static int probes_open(struct inode *inode, struct file *file)
 848 {
 849         int ret;
 850
 851         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
 852                 ret = release_all_trace_kprobes();
 853                 if (ret < 0)
 854                         return ret;
 855         }
 856
 857         return seq_open(file, &probes_seq_op);
 858 }
 859
 860 static ssize_t probes_write(struct file *file, const char __user *buffer,
 861                             size_t count, loff_t *ppos)
 862 {
 863         return traceprobe_probes_write(file, buffer, count, ppos,
 864                         create_trace_kprobe);
 865 }
 866
 867 static const struct file_operations kprobe_events_ops = {
 868         .owner          = THIS_MODULE,
 869         .open           = probes_open,
 870         .read           = seq_read,
 871         .llseek         = seq_lseek,
 872         .release        = seq_release,
 873         .write          = probes_write,
 874 };
 875
 876 /* Probes profiling interfaces */
 877 static int probes_profile_seq_show(struct seq_file *m, void *v)
 878 {
 879         struct trace_kprobe *tk = v;
 880         unsigned long nhit = 0;
 881         int cpu;
 882
 883         for_each_possible_cpu(cpu)
 884                 nhit += *per_cpu_ptr(tk->nhit, cpu);
 885
 886         seq_printf(m, "  %-44s %15lu %15lu\n",
 887                    trace_event_name(&tk->tp.call), nhit,
 888                    tk->rp.kp.nmissed);
 889
 890         return 0;
 891 }
 892
 893 static const struct seq_operations profile_seq_op = {
 894         .start  = probes_seq_start,
 895         .next   = probes_seq_next,
 896         .stop   = probes_seq_stop,
 897         .show   = probes_profile_seq_show
 898 };
 899
 900 static int profile_open(struct inode *inode, struct file *file)
 901 {
 902         return seq_open(file, &profile_seq_op);
 903 }
 904
 905 static const struct file_operations kprobe_profile_ops = {
 906         .owner          = THIS_MODULE,
 907         .open           = profile_open,
 908         .read           = seq_read,
 909         .llseek         = seq_lseek,
 910         .release        = seq_release,
 911 };
 912
 913 /* Kprobe handler */
 914 static nokprobe_inline void
 915 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
 916                     struct trace_event_file *trace_file)
 917 {
 918         struct kprobe_trace_entry_head *entry;
 919         struct ring_buffer_event *event;
 920         struct ring_buffer *buffer;
 921         int size, dsize, pc;
 922         unsigned long irq_flags;
 923         struct trace_event_call *call = &tk->tp.call;
 924
 925         WARN_ON(call != trace_file->event_call);
 926
 927         if (trace_trigger_soft_disabled(trace_file))
 928                 return;
 929
 930         local_save_flags(irq_flags);
 931         pc = preempt_count();
 932
 933         dsize = __get_data_size(&tk->tp, regs);
 934         size = sizeof(*entry) + tk->tp.size + dsize;
 935
 936         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
 937                                                 call->event.type,
 938                                                 size, irq_flags, pc);
 939         if (!event)
 940                 return;
 941
 942         entry = ring_buffer_event_data(event);
 943         entry->ip = (unsigned long)tk->rp.kp.addr;
 944         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
 945
 946         event_trigger_unlock_commit_regs(trace_file, buffer, event,
 947                                          entry, irq_flags, pc, regs);
 948 }
 949
 950 static void
 951 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
 952 {
 953         struct event_file_link *link;
 954
 955         list_for_each_entry_rcu(link, &tk->tp.files, list)
 956                 __kprobe_trace_func(tk, regs, link->file);
 957 }
 958 NOKPROBE_SYMBOL(kprobe_trace_func);
 959
 960 /* Kretprobe handler */
 961 static nokprobe_inline void
 962 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
 963                        struct pt_regs *regs,
 964                        struct trace_event_file *trace_file)
 965 {
 966         struct kretprobe_trace_entry_head *entry;
 967         struct ring_buffer_event *event;
 968         struct ring_buffer *buffer;
 969         int size, pc, dsize;
 970         unsigned long irq_flags;
 971         struct trace_event_call *call = &tk->tp.call;
 972
 973         WARN_ON(call != trace_file->event_call);
 974
 975         if (trace_trigger_soft_disabled(trace_file))
 976                 return;
 977
 978         local_save_flags(irq_flags);
 979         pc = preempt_count();
 980
 981         dsize = __get_data_size(&tk->tp, regs);
 982         size = sizeof(*entry) + tk->tp.size + dsize;
 983
 984         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
 985                                                 call->event.type,
 986                                                 size, irq_flags, pc);
 987         if (!event)
 988                 return;
 989
 990         entry = ring_buffer_event_data(event);
 991         entry->func = (unsigned long)tk->rp.kp.addr;
 992         entry->ret_ip = (unsigned long)ri->ret_addr;
 993         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
 994
 995         event_trigger_unlock_commit_regs(trace_file, buffer, event,
 996                                          entry, irq_flags, pc, regs);
 997 }
 998
 999 static void
1000 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1001                      struct pt_regs *regs)
1002 {
1003         struct event_file_link *link;
1004
1005         list_for_each_entry_rcu(link, &tk->tp.files, list)
1006                 __kretprobe_trace_func(tk, ri, regs, link->file);
1007 }
1008 NOKPROBE_SYMBOL(kretprobe_trace_func);
1009
1010 /* Event entry printers */
1011 static enum print_line_t
1012 print_kprobe_event(struct trace_iterator *iter, int flags,
1013                    struct trace_event *event)
1014 {
1015         struct kprobe_trace_entry_head *field;
1016         struct trace_seq *s = &iter->seq;
1017         struct trace_probe *tp;
1018         u8 *data;
1019         int i;
1020
1021         field = (struct kprobe_trace_entry_head *)iter->ent;
1022         tp = container_of(event, struct trace_probe, call.event);
1023
1024         trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1025
1026         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1027                 goto out;
1028
1029         trace_seq_putc(s, ')');
1030
1031         data = (u8 *)&field[1];
1032         for (i = 0; i < tp->nr_args; i++)
1033                 if (!tp->args[i].type->print(s, tp->args[i].name,
1034                                              data + tp->args[i].offset, field))
1035                         goto out;
1036
1037         trace_seq_putc(s, '\n');
1038  out:
1039         return trace_handle_return(s);
1040 }
1041
1042 static enum print_line_t
1043 print_kretprobe_event(struct trace_iterator *iter, int flags,
1044                       struct trace_event *event)
1045 {
1046         struct kretprobe_trace_entry_head *field;
1047         struct trace_seq *s = &iter->seq;
1048         struct trace_probe *tp;
1049         u8 *data;
1050         int i;
1051
1052         field = (struct kretprobe_trace_entry_head *)iter->ent;
1053         tp = container_of(event, struct trace_probe, call.event);
1054
1055         trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1056
1057         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1058                 goto out;
1059
1060         trace_seq_puts(s, " <- ");
1061
1062         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1063                 goto out;
1064
1065         trace_seq_putc(s, ')');
1066
1067         data = (u8 *)&field[1];
1068         for (i = 0; i < tp->nr_args; i++)
1069                 if (!tp->args[i].type->print(s, tp->args[i].name,
1070                                              data + tp->args[i].offset, field))
1071                         goto out;
1072
1073         trace_seq_putc(s, '\n');
1074
1075  out:
1076         return trace_handle_return(s);
1077 }
1078
1079
1080 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1081 {
1082         int ret, i;
1083         struct kprobe_trace_entry_head field;
1084         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1085
1086         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1087         /* Set argument names as fields */
1088         for (i = 0; i < tk->tp.nr_args; i++) {
1089                 struct probe_arg *parg = &tk->tp.args[i];
1090
1091                 ret = trace_define_field(event_call, parg->type->fmttype,
1092                                          parg->name,
1093                                          sizeof(field) + parg->offset,
1094                                          parg->type->size,
1095                                          parg->type->is_signed,
1096                                          FILTER_OTHER);
1097                 if (ret)
1098                         return ret;
1099         }
1100         return 0;
1101 }
1102
1103 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1104 {
1105         int ret, i;
1106         struct kretprobe_trace_entry_head field;
1107         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1108
1109         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1110         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1111         /* Set argument names as fields */
1112         for (i = 0; i < tk->tp.nr_args; i++) {
1113                 struct probe_arg *parg = &tk->tp.args[i];
1114
1115                 ret = trace_define_field(event_call, parg->type->fmttype,
1116                                          parg->name,
1117                                          sizeof(field) + parg->offset,
1118                                          parg->type->size,
1119                                          parg->type->is_signed,
1120                                          FILTER_OTHER);
1121                 if (ret)
1122                         return ret;
1123         }
1124         return 0;
1125 }
1126
1127 #ifdef CONFIG_PERF_EVENTS
1128
1129 /* Kprobe profile handler */
1130 static void
1131 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1132 {
1133         struct trace_event_call *call = &tk->tp.call;
1134         struct bpf_prog *prog = call->prog;
1135         struct kprobe_trace_entry_head *entry;
1136         struct hlist_head *head;
1137         int size, __size, dsize;
1138         int rctx;
1139
1140         if (prog && !trace_call_bpf(prog, regs))
1141                 return;
1142
1143         head = this_cpu_ptr(call->perf_events);
1144         if (hlist_empty(head))
1145                 return;
1146
1147         dsize = __get_data_size(&tk->tp, regs);
1148         __size = sizeof(*entry) + tk->tp.size + dsize;
1149         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1150         size -= sizeof(u32);
1151
1152         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1153         if (!entry)
1154                 return;
1155
1156         entry->ip = (unsigned long)tk->rp.kp.addr;
1157         memset(&entry[1], 0, dsize);
1158         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1159         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1160                               head, NULL);
1161 }
1162 NOKPROBE_SYMBOL(kprobe_perf_func);
1163
1164 /* Kretprobe profile handler */
1165 static void
1166 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1167                     struct pt_regs *regs)
1168 {
1169         struct trace_event_call *call = &tk->tp.call;
1170         struct bpf_prog *prog = call->prog;
1171         struct kretprobe_trace_entry_head *entry;
1172         struct hlist_head *head;
1173         int size, __size, dsize;
1174         int rctx;
1175
1176         if (prog && !trace_call_bpf(prog, regs))
1177                 return;
1178
1179         head = this_cpu_ptr(call->perf_events);
1180         if (hlist_empty(head))
1181                 return;
1182
1183         dsize = __get_data_size(&tk->tp, regs);
1184         __size = sizeof(*entry) + tk->tp.size + dsize;
1185         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1186         size -= sizeof(u32);
1187
1188         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1189         if (!entry)
1190                 return;
1191
1192         entry->func = (unsigned long)tk->rp.kp.addr;
1193         entry->ret_ip = (unsigned long)ri->ret_addr;
1194         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1195         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1196                               head, NULL);
1197 }
1198 NOKPROBE_SYMBOL(kretprobe_perf_func);
1199 #endif  /* CONFIG_PERF_EVENTS */
1200
1201 /*
1202  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1203  *
1204  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1205  * lockless, but we can't race with this __init function.
1206  */
1207 static int kprobe_register(struct trace_event_call *event,
1208                            enum trace_reg type, void *data)
1209 {
1210         struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1211         struct trace_event_file *file = data;
1212
1213         switch (type) {
1214         case TRACE_REG_REGISTER:
1215                 return enable_trace_kprobe(tk, file);
1216         case TRACE_REG_UNREGISTER:
1217                 return disable_trace_kprobe(tk, file);
1218
1219 #ifdef CONFIG_PERF_EVENTS
1220         case TRACE_REG_PERF_REGISTER:
1221                 return enable_trace_kprobe(tk, NULL);
1222         case TRACE_REG_PERF_UNREGISTER:
1223                 return disable_trace_kprobe(tk, NULL);
1224         case TRACE_REG_PERF_OPEN:
1225         case TRACE_REG_PERF_CLOSE:
1226         case TRACE_REG_PERF_ADD:
1227         case TRACE_REG_PERF_DEL:
1228                 return 0;
1229 #endif
1230         }
1231         return 0;
1232 }
1233
1234 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1235 {
1236         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1237
1238         raw_cpu_inc(*tk->nhit);
1239
1240         if (tk->tp.flags & TP_FLAG_TRACE)
1241                 kprobe_trace_func(tk, regs);
1242 #ifdef CONFIG_PERF_EVENTS
1243         if (tk->tp.flags & TP_FLAG_PROFILE)
1244                 kprobe_perf_func(tk, regs);
1245 #endif
1246         return 0;       /* We don't tweek kernel, so just return 0 */
1247 }
1248 NOKPROBE_SYMBOL(kprobe_dispatcher);
1249
1250 static int
1251 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1252 {
1253         struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1254
1255         raw_cpu_inc(*tk->nhit);
1256
1257         if (tk->tp.flags & TP_FLAG_TRACE)
1258                 kretprobe_trace_func(tk, ri, regs);
1259 #ifdef CONFIG_PERF_EVENTS
1260         if (tk->tp.flags & TP_FLAG_PROFILE)
1261                 kretprobe_perf_func(tk, ri, regs);
1262 #endif
1263         return 0;       /* We don't tweek kernel, so just return 0 */
1264 }
1265 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1266
1267 static struct trace_event_functions kretprobe_funcs = {
1268         .trace          = print_kretprobe_event
1269 };
1270
1271 static struct trace_event_functions kprobe_funcs = {
1272         .trace          = print_kprobe_event
1273 };
1274
1275 static int register_kprobe_event(struct trace_kprobe *tk)
1276 {
1277         struct trace_event_call *call = &tk->tp.call;
1278         int ret;
1279
1280         /* Initialize trace_event_call */
1281         INIT_LIST_HEAD(&call->class->fields);
1282         if (trace_kprobe_is_return(tk)) {
1283                 call->event.funcs = &kretprobe_funcs;
1284                 call->class->define_fields = kretprobe_event_define_fields;
1285         } else {
1286                 call->event.funcs = &kprobe_funcs;
1287                 call->class->define_fields = kprobe_event_define_fields;
1288         }
1289         if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1290                 return -ENOMEM;
1291         ret = register_trace_event(&call->event);
1292         if (!ret) {
1293                 kfree(call->print_fmt);
1294                 return -ENODEV;
1295         }
1296         call->flags = TRACE_EVENT_FL_KPROBE;
1297         call->class->reg = kprobe_register;
1298         call->data = tk;
1299         ret = trace_add_event_call(call);
1300         if (ret) {
1301                 pr_info("Failed to register kprobe event: %s\n",
1302                         trace_event_name(call));
1303                 kfree(call->print_fmt);
1304                 unregister_trace_event(&call->event);
1305         }
1306         return ret;
1307 }
1308
1309 static int unregister_kprobe_event(struct trace_kprobe *tk)
1310 {
1311         int ret;
1312
1313         /* tp->event is unregistered in trace_remove_event_call() */
1314         ret = trace_remove_event_call(&tk->tp.call);
1315         if (!ret)
1316                 kfree(tk->tp.call.print_fmt);
1317         return ret;
1318 }
1319
1320 /* Make a tracefs interface for controlling probe points */
1321 static __init int init_kprobe_trace(void)
1322 {
1323         struct dentry *d_tracer;
1324         struct dentry *entry;
1325
1326         if (register_module_notifier(&trace_kprobe_module_nb))
1327                 return -EINVAL;
1328
1329         d_tracer = tracing_init_dentry();
1330         if (IS_ERR(d_tracer))
1331                 return 0;
1332
1333         entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1334                                     NULL, &kprobe_events_ops);
1335
1336         /* Event list interface */
1337         if (!entry)
1338                 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1339
1340         /* Profile interface */
1341         entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1342                                     NULL, &kprobe_profile_ops);
1343
1344         if (!entry)
1345                 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1346         return 0;
1347 }
1348 fs_initcall(init_kprobe_trace);
1349
1350
1351 #ifdef CONFIG_FTRACE_STARTUP_TEST
1352
1353 /*
1354  * The "__used" keeps gcc from removing the function symbol
1355  * from the kallsyms table.
1356  */
1357 static __used int kprobe_trace_selftest_target(int a1, int a2, int a3,
1358                                                int a4, int a5, int a6)
1359 {
1360         return a1 + a2 + a3 + a4 + a5 + a6;
1361 }
1362
1363 static struct trace_event_file *
1364 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1365 {
1366         struct trace_event_file *file;
1367
1368         list_for_each_entry(file, &tr->events, list)
1369                 if (file->event_call == &tk->tp.call)
1370                         return file;
1371
1372         return NULL;
1373 }
1374
1375 /*
1376  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1377  * stage, we can do this lockless.
1378  */
1379 static __init int kprobe_trace_self_tests_init(void)
1380 {
1381         int ret, warn = 0;
1382         int (*target)(int, int, int, int, int, int);
1383         struct trace_kprobe *tk;
1384         struct trace_event_file *file;
1385
1386         if (tracing_is_disabled())
1387                 return -ENODEV;
1388
1389         target = kprobe_trace_selftest_target;
1390
1391         pr_info("Testing kprobe tracing: ");
1392
1393         ret = traceprobe_command("p:testprobe kprobe_trace_selftest_target "
1394                                   "$stack $stack0 +0($stack)",
1395                                   create_trace_kprobe);
1396         if (WARN_ON_ONCE(ret)) {
1397                 pr_warn("error on probing function entry.\n");
1398                 warn++;
1399         } else {
1400                 /* Enable trace point */
1401                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1402                 if (WARN_ON_ONCE(tk == NULL)) {
1403                         pr_warn("error on getting new probe.\n");
1404                         warn++;
1405                 } else {
1406                         file = find_trace_probe_file(tk, top_trace_array());
1407                         if (WARN_ON_ONCE(file == NULL)) {
1408                                 pr_warn("error on getting probe file.\n");
1409                                 warn++;
1410                         } else
1411                                 enable_trace_kprobe(tk, file);
1412                 }
1413         }
1414
1415         ret = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target "
1416                                   "$retval", create_trace_kprobe);
1417         if (WARN_ON_ONCE(ret)) {
1418                 pr_warn("error on probing function return.\n");
1419                 warn++;
1420         } else {
1421                 /* Enable trace point */
1422                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1423                 if (WARN_ON_ONCE(tk == NULL)) {
1424                         pr_warn("error on getting 2nd new probe.\n");
1425                         warn++;
1426                 } else {
1427                         file = find_trace_probe_file(tk, top_trace_array());
1428                         if (WARN_ON_ONCE(file == NULL)) {
1429                                 pr_warn("error on getting probe file.\n");
1430                                 warn++;
1431                         } else
1432                                 enable_trace_kprobe(tk, file);
1433                 }
1434         }
1435
1436         if (warn)
1437                 goto end;
1438
1439         ret = target(1, 2, 3, 4, 5, 6);
1440
1441         /* Disable trace points before removing it */
1442         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1443         if (WARN_ON_ONCE(tk == NULL)) {
1444                 pr_warn("error on getting test probe.\n");
1445                 warn++;
1446         } else {
1447                 file = find_trace_probe_file(tk, top_trace_array());
1448                 if (WARN_ON_ONCE(file == NULL)) {
1449                         pr_warn("error on getting probe file.\n");
1450                         warn++;
1451                 } else
1452                         disable_trace_kprobe(tk, file);
1453         }
1454
1455         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1456         if (WARN_ON_ONCE(tk == NULL)) {
1457                 pr_warn("error on getting 2nd test probe.\n");
1458                 warn++;
1459         } else {
1460                 file = find_trace_probe_file(tk, top_trace_array());
1461                 if (WARN_ON_ONCE(file == NULL)) {
1462                         pr_warn("error on getting probe file.\n");
1463                         warn++;
1464                 } else
1465                         disable_trace_kprobe(tk, file);
1466         }
1467
1468         ret = traceprobe_command("-:testprobe", create_trace_kprobe);
1469         if (WARN_ON_ONCE(ret)) {
1470                 pr_warn("error on deleting a probe.\n");
1471                 warn++;
1472         }
1473
1474         ret = traceprobe_command("-:testprobe2", create_trace_kprobe);
1475         if (WARN_ON_ONCE(ret)) {
1476                 pr_warn("error on deleting a probe.\n");
1477                 warn++;
1478         }
1479
1480 end:
1481         release_all_trace_kprobes();
1482         if (warn)
1483                 pr_cont("NG: Some tests are failed. Please check them.\n");
1484         else
1485                 pr_cont("OK\n");
1486         return 0;
1487 }
1488
1489 late_initcall(kprobe_trace_self_tests_init);
1490
1491 #endif