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