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