kernel/trace/trace_kprobe.c

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