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         long ret;
 169         int maxlen = get_rloc_len(*(u32 *)dest);
 170         u8 *dst = get_rloc_data(dest);
 171         u8 *src = addr;
 172         mm_segment_t old_fs = get_fs();
 173
 174         if (!maxlen)
 175                 return;
 176
 177         /*
 178          * Try to get string again, since the string can be changed while
 179          * probing.
 180          */
 181         set_fs(KERNEL_DS);
 182         pagefault_disable();
 183
 184         do
 185                 ret = __copy_from_user_inatomic(dst++, src++, 1);
 186         while (dst[-1] && ret == 0 && src - (u8 *)addr < maxlen);
 187
 188         dst[-1] = '\0';
 189         pagefault_enable();
 190         set_fs(old_fs);
 191
 192         if (ret < 0) {  /* Failed to fetch string */
 193                 ((u8 *)get_rloc_data(dest))[0] = '\0';
 194                 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
 195         } else {
 196                 *(u32 *)dest = make_data_rloc(src - (u8 *)addr,
 197                                               get_rloc_offs(*(u32 *)dest));
 198         }
 199 }
 200 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string));
 201
 202 /* Return the length of string -- including null terminal byte */
 203 static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
 204                                                  void *addr, void *dest)
 205 {
 206         mm_segment_t old_fs;
 207         int ret, len = 0;
 208         u8 c;
 209
 210         old_fs = get_fs();
 211         set_fs(KERNEL_DS);
 212         pagefault_disable();
 213
 214         do {
 215                 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
 216                 len++;
 217         } while (c && ret == 0 && len < MAX_STRING_SIZE);
 218
 219         pagefault_enable();
 220         set_fs(old_fs);
 221
 222         if (ret < 0)    /* Failed to check the length */
 223                 *(u32 *)dest = 0;
 224         else
 225                 *(u32 *)dest = len;
 226 }
 227 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string_size));
 228
 229 #define DEFINE_FETCH_symbol(type)                                       \
 230 void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs, void *data, void *dest)\
 231 {                                                                       \
 232         struct symbol_cache *sc = data;                                 \
 233         if (sc->addr)                                                   \
 234                 fetch_memory_##type(regs, (void *)sc->addr, dest);      \
 235         else                                                            \
 236                 *(type *)dest = 0;                                      \
 237 }                                                                       \
 238 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(symbol, type));
 239
 240 DEFINE_BASIC_FETCH_FUNCS(symbol)
 241 DEFINE_FETCH_symbol(string)
 242 DEFINE_FETCH_symbol(string_size)
 243
 244 /* kprobes don't support file_offset fetch methods */
 245 #define fetch_file_offset_u8            NULL
 246 #define fetch_file_offset_u16           NULL
 247 #define fetch_file_offset_u32           NULL
 248 #define fetch_file_offset_u64           NULL
 249 #define fetch_file_offset_string        NULL
 250 #define fetch_file_offset_string_size   NULL
 251
 252 /* Fetch type information table */
 253 const struct fetch_type kprobes_fetch_type_table[] = {
 254         /* Special types */
 255         [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
 256                                         sizeof(u32), 1, "__data_loc char[]"),
 257         [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
 258                                         string_size, sizeof(u32), 0, "u32"),
 259         /* Basic types */
 260         ASSIGN_FETCH_TYPE(u8,  u8,  0),
 261         ASSIGN_FETCH_TYPE(u16, u16, 0),
 262         ASSIGN_FETCH_TYPE(u32, u32, 0),
 263         ASSIGN_FETCH_TYPE(u64, u64, 0),
 264         ASSIGN_FETCH_TYPE(s8,  u8,  1),
 265         ASSIGN_FETCH_TYPE(s16, u16, 1),
 266         ASSIGN_FETCH_TYPE(s32, u32, 1),
 267         ASSIGN_FETCH_TYPE(s64, u64, 1),
 268
 269         ASSIGN_FETCH_TYPE_END
 270 };
 271
 272 /*
 273  * Allocate new trace_probe and initialize it (including kprobes).
 274  */
 275 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
 276                                              const char *event,
 277                                              void *addr,
 278                                              const char *symbol,
 279                                              unsigned long offs,
 280                                              int nargs, bool is_return)
 281 {
 282         struct trace_kprobe *tk;
 283         int ret = -ENOMEM;
 284
 285         tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
 286         if (!tk)
 287                 return ERR_PTR(ret);
 288
 289         if (symbol) {
 290                 tk->symbol = kstrdup(symbol, GFP_KERNEL);
 291                 if (!tk->symbol)
 292                         goto error;
 293                 tk->rp.kp.symbol_name = tk->symbol;
 294                 tk->rp.kp.offset = offs;
 295         } else
 296                 tk->rp.kp.addr = addr;
 297
 298         if (is_return)
 299                 tk->rp.handler = kretprobe_dispatcher;
 300         else
 301                 tk->rp.kp.pre_handler = kprobe_dispatcher;
 302
 303         if (!event || !is_good_name(event)) {
 304                 ret = -EINVAL;
 305                 goto error;
 306         }
 307
 308         tk->tp.call.class = &tk->tp.class;
 309         tk->tp.call.name = kstrdup(event, GFP_KERNEL);
 310         if (!tk->tp.call.name)
 311                 goto error;
 312
 313         if (!group || !is_good_name(group)) {
 314                 ret = -EINVAL;
 315                 goto error;
 316         }
 317
 318         tk->tp.class.system = kstrdup(group, GFP_KERNEL);
 319         if (!tk->tp.class.system)
 320                 goto error;
 321
 322         INIT_LIST_HEAD(&tk->list);
 323         INIT_LIST_HEAD(&tk->tp.files);
 324         return tk;
 325 error:
 326         kfree(tk->tp.call.name);
 327         kfree(tk->symbol);
 328         kfree(tk);
 329         return ERR_PTR(ret);
 330 }
 331
 332 static void free_trace_kprobe(struct trace_kprobe *tk)
 333 {
 334         int i;
 335
 336         for (i = 0; i < tk->tp.nr_args; i++)
 337                 traceprobe_free_probe_arg(&tk->tp.args[i]);
 338
 339         kfree(tk->tp.call.class->system);
 340         kfree(tk->tp.call.name);
 341         kfree(tk->symbol);
 342         kfree(tk);
 343 }
 344
 345 static struct trace_kprobe *find_trace_kprobe(const char *event,
 346                                               const char *group)
 347 {
 348         struct trace_kprobe *tk;
 349
 350         list_for_each_entry(tk, &probe_list, list)
 351                 if (strcmp(ftrace_event_name(&tk->tp.call), event) == 0 &&
 352                     strcmp(tk->tp.call.class->system, group) == 0)
 353                         return tk;
 354         return NULL;
 355 }
 356
 357 /*
 358  * Enable trace_probe
 359  * if the file is NULL, enable "perf" handler, or enable "trace" handler.
 360  */
 361 static int
 362 enable_trace_kprobe(struct trace_kprobe *tk, struct ftrace_event_file *file)
 363 {
 364         int ret = 0;
 365
 366         if (file) {
 367                 struct event_file_link *link;
 368
 369                 link = kmalloc(sizeof(*link), GFP_KERNEL);
 370                 if (!link) {
 371                         ret = -ENOMEM;
 372                         goto out;
 373                 }
 374
 375                 link->file = file;
 376                 list_add_tail_rcu(&link->list, &tk->tp.files);
 377
 378                 tk->tp.flags |= TP_FLAG_TRACE;
 379         } else
 380                 tk->tp.flags |= TP_FLAG_PROFILE;
 381
 382         if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
 383                 if (trace_kprobe_is_return(tk))
 384                         ret = enable_kretprobe(&tk->rp);
 385                 else
 386                         ret = enable_kprobe(&tk->rp.kp);
 387         }
 388  out:
 389         return ret;
 390 }
 391
 392 /*
 393  * Disable trace_probe
 394  * if the file is NULL, disable "perf" handler, or disable "trace" handler.
 395  */
 396 static int
 397 disable_trace_kprobe(struct trace_kprobe *tk, struct ftrace_event_file *file)
 398 {
 399         struct event_file_link *link = NULL;
 400         int wait = 0;
 401         int ret = 0;
 402
 403         if (file) {
 404                 link = find_event_file_link(&tk->tp, file);
 405                 if (!link) {
 406                         ret = -EINVAL;
 407                         goto out;
 408                 }
 409
 410                 list_del_rcu(&link->list);
 411                 wait = 1;
 412                 if (!list_empty(&tk->tp.files))
 413                         goto out;
 414
 415                 tk->tp.flags &= ~TP_FLAG_TRACE;
 416         } else
 417                 tk->tp.flags &= ~TP_FLAG_PROFILE;
 418
 419         if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
 420                 if (trace_kprobe_is_return(tk))
 421                         disable_kretprobe(&tk->rp);
 422                 else
 423                         disable_kprobe(&tk->rp.kp);
 424                 wait = 1;
 425         }
 426  out:
 427         if (wait) {
 428                 /*
 429                  * Synchronize with kprobe_trace_func/kretprobe_trace_func
 430                  * to ensure disabled (all running handlers are finished).
 431                  * This is not only for kfree(), but also the caller,
 432                  * trace_remove_event_call() supposes it for releasing
 433                  * event_call related objects, which will be accessed in
 434                  * the kprobe_trace_func/kretprobe_trace_func.
 435                  */
 436                 synchronize_sched();
 437                 kfree(link);    /* Ignored if link == NULL */
 438         }
 439
 440         return ret;
 441 }
 442
 443 /* Internal register function - just handle k*probes and flags */
 444 static int __register_trace_kprobe(struct trace_kprobe *tk)
 445 {
 446         int i, ret;
 447
 448         if (trace_probe_is_registered(&tk->tp))
 449                 return -EINVAL;
 450
 451         for (i = 0; i < tk->tp.nr_args; i++)
 452                 traceprobe_update_arg(&tk->tp.args[i]);
 453
 454         /* Set/clear disabled flag according to tp->flag */
 455         if (trace_probe_is_enabled(&tk->tp))
 456                 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
 457         else
 458                 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 459
 460         if (trace_kprobe_is_return(tk))
 461                 ret = register_kretprobe(&tk->rp);
 462         else
 463                 ret = register_kprobe(&tk->rp.kp);
 464
 465         if (ret == 0)
 466                 tk->tp.flags |= TP_FLAG_REGISTERED;
 467         else {
 468                 pr_warning("Could not insert probe at %s+%lu: %d\n",
 469                            trace_kprobe_symbol(tk), trace_kprobe_offset(tk), ret);
 470                 if (ret == -ENOENT && trace_kprobe_is_on_module(tk)) {
 471                         pr_warning("This probe might be able to register after"
 472                                    "target module is loaded. Continue.\n");
 473                         ret = 0;
 474                 } else if (ret == -EILSEQ) {
 475                         pr_warning("Probing address(0x%p) is not an "
 476                                    "instruction boundary.\n",
 477                                    tk->rp.kp.addr);
 478                         ret = -EINVAL;
 479                 }
 480         }
 481
 482         return ret;
 483 }
 484
 485 /* Internal unregister function - just handle k*probes and flags */
 486 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
 487 {
 488         if (trace_probe_is_registered(&tk->tp)) {
 489                 if (trace_kprobe_is_return(tk))
 490                         unregister_kretprobe(&tk->rp);
 491                 else
 492                         unregister_kprobe(&tk->rp.kp);
 493                 tk->tp.flags &= ~TP_FLAG_REGISTERED;
 494                 /* Cleanup kprobe for reuse */
 495                 if (tk->rp.kp.symbol_name)
 496                         tk->rp.kp.addr = NULL;
 497         }
 498 }
 499
 500 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
 501 static int unregister_trace_kprobe(struct trace_kprobe *tk)
 502 {
 503         /* Enabled event can not be unregistered */
 504         if (trace_probe_is_enabled(&tk->tp))
 505                 return -EBUSY;
 506
 507         /* Will fail if probe is being used by ftrace or perf */
 508         if (unregister_kprobe_event(tk))
 509                 return -EBUSY;
 510
 511         __unregister_trace_kprobe(tk);
 512         list_del(&tk->list);
 513
 514         return 0;
 515 }
 516
 517 /* Register a trace_probe and probe_event */
 518 static int register_trace_kprobe(struct trace_kprobe *tk)
 519 {
 520         struct trace_kprobe *old_tk;
 521         int ret;
 522
 523         mutex_lock(&probe_lock);
 524
 525         /* Delete old (same name) event if exist */
 526         old_tk = find_trace_kprobe(ftrace_event_name(&tk->tp.call),
 527                         tk->tp.call.class->system);
 528         if (old_tk) {
 529                 ret = unregister_trace_kprobe(old_tk);
 530                 if (ret < 0)
 531                         goto end;
 532                 free_trace_kprobe(old_tk);
 533         }
 534
 535         /* Register new event */
 536         ret = register_kprobe_event(tk);
 537         if (ret) {
 538                 pr_warning("Failed to register probe event(%d)\n", ret);
 539                 goto end;
 540         }
 541
 542         /* Register k*probe */
 543         ret = __register_trace_kprobe(tk);
 544         if (ret < 0)
 545                 unregister_kprobe_event(tk);
 546         else
 547                 list_add_tail(&tk->list, &probe_list);
 548
 549 end:
 550         mutex_unlock(&probe_lock);
 551         return ret;
 552 }
 553
 554 /* Module notifier call back, checking event on the module */
 555 static int trace_kprobe_module_callback(struct notifier_block *nb,
 556                                        unsigned long val, void *data)
 557 {
 558         struct module *mod = data;
 559         struct trace_kprobe *tk;
 560         int ret;
 561
 562         if (val != MODULE_STATE_COMING)
 563                 return NOTIFY_DONE;
 564
 565         /* Update probes on coming module */
 566         mutex_lock(&probe_lock);
 567         list_for_each_entry(tk, &probe_list, list) {
 568                 if (trace_kprobe_within_module(tk, mod)) {
 569                         /* Don't need to check busy - this should have gone. */
 570                         __unregister_trace_kprobe(tk);
 571                         ret = __register_trace_kprobe(tk);
 572                         if (ret)
 573                                 pr_warning("Failed to re-register probe %s on"
 574                                            "%s: %d\n",
 575                                            ftrace_event_name(&tk->tp.call),
 576                                            mod->name, ret);
 577                 }
 578         }
 579         mutex_unlock(&probe_lock);
 580
 581         return NOTIFY_DONE;
 582 }
 583
 584 static struct notifier_block trace_kprobe_module_nb = {
 585         .notifier_call = trace_kprobe_module_callback,
 586         .priority = 1   /* Invoked after kprobe module callback */
 587 };
 588
 589 static int create_trace_kprobe(int argc, char **argv)
 590 {
 591         /*
 592          * Argument syntax:
 593          *  - Add kprobe: p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
 594          *  - Add kretprobe: r[:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
 595          * Fetch args:
 596          *  $retval     : fetch return value
 597          *  $stack      : fetch stack address
 598          *  $stackN     : fetch Nth of stack (N:0-)
 599          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 600          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 601          *  %REG        : fetch register REG
 602          * Dereferencing memory fetch:
 603          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 604          * Alias name of args:
 605          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 606          * Type of args:
 607          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 608          */
 609         struct trace_kprobe *tk;
 610         int i, ret = 0;
 611         bool is_return = false, is_delete = false;
 612         char *symbol = NULL, *event = NULL, *group = NULL;
 613         char *arg;
 614         unsigned long offset = 0;
 615         void *addr = NULL;
 616         char buf[MAX_EVENT_NAME_LEN];
 617
 618         /* argc must be >= 1 */
 619         if (argv[0][0] == 'p')
 620                 is_return = false;
 621         else if (argv[0][0] == 'r')
 622                 is_return = true;
 623         else if (argv[0][0] == '-')
 624                 is_delete = true;
 625         else {
 626                 pr_info("Probe definition must be started with 'p', 'r' or"
 627                         " '-'.\n");
 628                 return -EINVAL;
 629         }
 630
 631         if (argv[0][1] == ':') {
 632                 event = &argv[0][2];
 633                 if (strchr(event, '/')) {
 634                         group = event;
 635                         event = strchr(group, '/') + 1;
 636                         event[-1] = '\0';
 637                         if (strlen(group) == 0) {
 638                                 pr_info("Group name is not specified\n");
 639                                 return -EINVAL;
 640                         }
 641                 }
 642                 if (strlen(event) == 0) {
 643                         pr_info("Event name is not specified\n");
 644                         return -EINVAL;
 645                 }
 646         }
 647         if (!group)
 648                 group = KPROBE_EVENT_SYSTEM;
 649
 650         if (is_delete) {
 651                 if (!event) {
 652                         pr_info("Delete command needs an event name.\n");
 653                         return -EINVAL;
 654                 }
 655                 mutex_lock(&probe_lock);
 656                 tk = find_trace_kprobe(event, group);
 657                 if (!tk) {
 658                         mutex_unlock(&probe_lock);
 659                         pr_info("Event %s/%s doesn't exist.\n", group, event);
 660                         return -ENOENT;
 661                 }
 662                 /* delete an event */
 663                 ret = unregister_trace_kprobe(tk);
 664                 if (ret == 0)
 665                         free_trace_kprobe(tk);
 666                 mutex_unlock(&probe_lock);
 667                 return ret;
 668         }
 669
 670         if (argc < 2) {
 671                 pr_info("Probe point is not specified.\n");
 672                 return -EINVAL;
 673         }
 674         if (isdigit(argv[1][0])) {
 675                 if (is_return) {
 676                         pr_info("Return probe point must be a symbol.\n");
 677                         return -EINVAL;
 678                 }
 679                 /* an address specified */
 680                 ret = kstrtoul(&argv[1][0], 0, (unsigned long *)&addr);
 681                 if (ret) {
 682                         pr_info("Failed to parse address.\n");
 683                         return ret;
 684                 }
 685         } else {
 686                 /* a symbol specified */
 687                 symbol = argv[1];
 688                 /* TODO: support .init module functions */
 689                 ret = traceprobe_split_symbol_offset(symbol, &offset);
 690                 if (ret) {
 691                         pr_info("Failed to parse symbol.\n");
 692                         return ret;
 693                 }
 694                 if (offset && is_return) {
 695                         pr_info("Return probe must be used without offset.\n");
 696                         return -EINVAL;
 697                 }
 698         }
 699         argc -= 2; argv += 2;
 700
 701         /* setup a probe */
 702         if (!event) {
 703                 /* Make a new event name */
 704                 if (symbol)
 705                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 706                                  is_return ? 'r' : 'p', symbol, offset);
 707                 else
 708                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 709                                  is_return ? 'r' : 'p', addr);
 710                 event = buf;
 711         }
 712         tk = alloc_trace_kprobe(group, event, addr, symbol, offset, argc,
 713                                is_return);
 714         if (IS_ERR(tk)) {
 715                 pr_info("Failed to allocate trace_probe.(%d)\n",
 716                         (int)PTR_ERR(tk));
 717                 return PTR_ERR(tk);
 718         }
 719
 720         /* parse arguments */
 721         ret = 0;
 722         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 723                 struct probe_arg *parg = &tk->tp.args[i];
 724
 725                 /* Increment count for freeing args in error case */
 726                 tk->tp.nr_args++;
 727
 728                 /* Parse argument name */
 729                 arg = strchr(argv[i], '=');
 730                 if (arg) {
 731                         *arg++ = '\0';
 732                         parg->name = kstrdup(argv[i], GFP_KERNEL);
 733                 } else {
 734                         arg = argv[i];
 735                         /* If argument name is omitted, set "argN" */
 736                         snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
 737                         parg->name = kstrdup(buf, GFP_KERNEL);
 738                 }
 739
 740                 if (!parg->name) {
 741                         pr_info("Failed to allocate argument[%d] name.\n", i);
 742                         ret = -ENOMEM;
 743                         goto error;
 744                 }
 745
 746                 if (!is_good_name(parg->name)) {
 747                         pr_info("Invalid argument[%d] name: %s\n",
 748                                 i, parg->name);
 749                         ret = -EINVAL;
 750                         goto error;
 751                 }
 752
 753                 if (traceprobe_conflict_field_name(parg->name,
 754                                                         tk->tp.args, i)) {
 755                         pr_info("Argument[%d] name '%s' conflicts with "
 756                                 "another field.\n", i, argv[i]);
 757                         ret = -EINVAL;
 758                         goto error;
 759                 }
 760
 761                 /* Parse fetch argument */
 762                 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
 763                                                 is_return, true);
 764                 if (ret) {
 765                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
 766                         goto error;
 767                 }
 768         }
 769
 770         ret = register_trace_kprobe(tk);
 771         if (ret)
 772                 goto error;
 773         return 0;
 774
 775 error:
 776         free_trace_kprobe(tk);
 777         return ret;
 778 }
 779
 780 static int release_all_trace_kprobes(void)
 781 {
 782         struct trace_kprobe *tk;
 783         int ret = 0;
 784
 785         mutex_lock(&probe_lock);
 786         /* Ensure no probe is in use. */
 787         list_for_each_entry(tk, &probe_list, list)
 788                 if (trace_probe_is_enabled(&tk->tp)) {
 789                         ret = -EBUSY;
 790                         goto end;
 791                 }
 792         /* TODO: Use batch unregistration */
 793         while (!list_empty(&probe_list)) {
 794                 tk = list_entry(probe_list.next, struct trace_kprobe, list);
 795                 ret = unregister_trace_kprobe(tk);
 796                 if (ret)
 797                         goto end;
 798                 free_trace_kprobe(tk);
 799         }
 800
 801 end:
 802         mutex_unlock(&probe_lock);
 803
 804         return ret;
 805 }
 806
 807 /* Probes listing interfaces */
 808 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
 809 {
 810         mutex_lock(&probe_lock);
 811         return seq_list_start(&probe_list, *pos);
 812 }
 813
 814 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
 815 {
 816         return seq_list_next(v, &probe_list, pos);
 817 }
 818
 819 static void probes_seq_stop(struct seq_file *m, void *v)
 820 {
 821         mutex_unlock(&probe_lock);
 822 }
 823
 824 static int probes_seq_show(struct seq_file *m, void *v)
 825 {
 826         struct trace_kprobe *tk = v;
 827         int i;
 828
 829         seq_printf(m, "%c", trace_kprobe_is_return(tk) ? 'r' : 'p');
 830         seq_printf(m, ":%s/%s", tk->tp.call.class->system,
 831                         ftrace_event_name(&tk->tp.call));
 832
 833         if (!tk->symbol)
 834                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
 835         else if (tk->rp.kp.offset)
 836                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
 837                            tk->rp.kp.offset);
 838         else
 839                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
 840
 841         for (i = 0; i < tk->tp.nr_args; i++)
 842                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
 843         seq_printf(m, "\n");
 844
 845         return 0;
 846 }
 847
 848 static const struct seq_operations probes_seq_op = {
 849         .start  = probes_seq_start,
 850         .next   = probes_seq_next,
 851         .stop   = probes_seq_stop,
 852         .show   = probes_seq_show
 853 };
 854
 855 static int probes_open(struct inode *inode, struct file *file)
 856 {
 857         int ret;
 858
 859         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
 860                 ret = release_all_trace_kprobes();
 861                 if (ret < 0)
 862                         return ret;
 863         }
 864
 865         return seq_open(file, &probes_seq_op);
 866 }
 867
 868 static ssize_t probes_write(struct file *file, const char __user *buffer,
 869                             size_t count, loff_t *ppos)
 870 {
 871         return traceprobe_probes_write(file, buffer, count, ppos,
 872                         create_trace_kprobe);
 873 }
 874
 875 static const struct file_operations kprobe_events_ops = {
 876         .owner          = THIS_MODULE,
 877         .open           = probes_open,
 878         .read           = seq_read,
 879         .llseek         = seq_lseek,
 880         .release        = seq_release,
 881         .write          = probes_write,
 882 };
 883
 884 /* Probes profiling interfaces */
 885 static int probes_profile_seq_show(struct seq_file *m, void *v)
 886 {
 887         struct trace_kprobe *tk = v;
 888
 889         seq_printf(m, "  %-44s %15lu %15lu\n",
 890                    ftrace_event_name(&tk->tp.call), tk->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 ftrace_event_file *ftrace_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 ftrace_event_call *call = &tk->tp.call;
 927
 928         WARN_ON(call != ftrace_file->event_call);
 929
 930         if (ftrace_trigger_soft_disabled(ftrace_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, ftrace_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(ftrace_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 ftrace_event_file *ftrace_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 ftrace_event_call *call = &tk->tp.call;
 975
 976         WARN_ON(call != ftrace_file->event_call);
 977
 978         if (ftrace_trigger_soft_disabled(ftrace_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, ftrace_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(ftrace_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         if (!trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call)))
1028                 goto partial;
1029
1030         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1031                 goto partial;
1032
1033         if (!trace_seq_puts(s, ")"))
1034                 goto partial;
1035
1036         data = (u8 *)&field[1];
1037         for (i = 0; i < tp->nr_args; i++)
1038                 if (!tp->args[i].type->print(s, tp->args[i].name,
1039                                              data + tp->args[i].offset, field))
1040                         goto partial;
1041
1042         if (!trace_seq_puts(s, "\n"))
1043                 goto partial;
1044
1045         return TRACE_TYPE_HANDLED;
1046 partial:
1047         return TRACE_TYPE_PARTIAL_LINE;
1048 }
1049
1050 static enum print_line_t
1051 print_kretprobe_event(struct trace_iterator *iter, int flags,
1052                       struct trace_event *event)
1053 {
1054         struct kretprobe_trace_entry_head *field;
1055         struct trace_seq *s = &iter->seq;
1056         struct trace_probe *tp;
1057         u8 *data;
1058         int i;
1059
1060         field = (struct kretprobe_trace_entry_head *)iter->ent;
1061         tp = container_of(event, struct trace_probe, call.event);
1062
1063         if (!trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call)))
1064                 goto partial;
1065
1066         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1067                 goto partial;
1068
1069         if (!trace_seq_puts(s, " <- "))
1070                 goto partial;
1071
1072         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1073                 goto partial;
1074
1075         if (!trace_seq_puts(s, ")"))
1076                 goto partial;
1077
1078         data = (u8 *)&field[1];
1079         for (i = 0; i < tp->nr_args; i++)
1080                 if (!tp->args[i].type->print(s, tp->args[i].name,
1081                                              data + tp->args[i].offset, field))
1082                         goto partial;
1083
1084         if (!trace_seq_puts(s, "\n"))
1085                 goto partial;
1086
1087         return TRACE_TYPE_HANDLED;
1088 partial:
1089         return TRACE_TYPE_PARTIAL_LINE;
1090 }
1091
1092
1093 static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1094 {
1095         int ret, i;
1096         struct kprobe_trace_entry_head field;
1097         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1098
1099         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1100         /* Set argument names as fields */
1101         for (i = 0; i < tk->tp.nr_args; i++) {
1102                 struct probe_arg *parg = &tk->tp.args[i];
1103
1104                 ret = trace_define_field(event_call, parg->type->fmttype,
1105                                          parg->name,
1106                                          sizeof(field) + parg->offset,
1107                                          parg->type->size,
1108                                          parg->type->is_signed,
1109                                          FILTER_OTHER);
1110                 if (ret)
1111                         return ret;
1112         }
1113         return 0;
1114 }
1115
1116 static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1117 {
1118         int ret, i;
1119         struct kretprobe_trace_entry_head field;
1120         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1121
1122         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1123         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1124         /* Set argument names as fields */
1125         for (i = 0; i < tk->tp.nr_args; i++) {
1126                 struct probe_arg *parg = &tk->tp.args[i];
1127
1128                 ret = trace_define_field(event_call, parg->type->fmttype,
1129                                          parg->name,
1130                                          sizeof(field) + parg->offset,
1131                                          parg->type->size,
1132                                          parg->type->is_signed,
1133                                          FILTER_OTHER);
1134                 if (ret)
1135                         return ret;
1136         }
1137         return 0;
1138 }
1139
1140 #ifdef CONFIG_PERF_EVENTS
1141
1142 /* Kprobe profile handler */
1143 static void
1144 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1145 {
1146         struct ftrace_event_call *call = &tk->tp.call;
1147         struct kprobe_trace_entry_head *entry;
1148         struct hlist_head *head;
1149         int size, __size, dsize;
1150         int rctx;
1151
1152         head = this_cpu_ptr(call->perf_events);
1153         if (hlist_empty(head))
1154                 return;
1155
1156         dsize = __get_data_size(&tk->tp, regs);
1157         __size = sizeof(*entry) + tk->tp.size + dsize;
1158         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1159         size -= sizeof(u32);
1160
1161         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1162         if (!entry)
1163                 return;
1164
1165         entry->ip = (unsigned long)tk->rp.kp.addr;
1166         memset(&entry[1], 0, dsize);
1167         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1168         perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1169 }
1170 NOKPROBE_SYMBOL(kprobe_perf_func);
1171
1172 /* Kretprobe profile handler */
1173 static void
1174 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1175                     struct pt_regs *regs)
1176 {
1177         struct ftrace_event_call *call = &tk->tp.call;
1178         struct kretprobe_trace_entry_head *entry;
1179         struct hlist_head *head;
1180         int size, __size, dsize;
1181         int rctx;
1182
1183         head = this_cpu_ptr(call->perf_events);
1184         if (hlist_empty(head))
1185                 return;
1186
1187         dsize = __get_data_size(&tk->tp, regs);
1188         __size = sizeof(*entry) + tk->tp.size + dsize;
1189         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1190         size -= sizeof(u32);
1191
1192         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1193         if (!entry)
1194                 return;
1195
1196         entry->func = (unsigned long)tk->rp.kp.addr;
1197         entry->ret_ip = (unsigned long)ri->ret_addr;
1198         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1199         perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1200 }
1201 NOKPROBE_SYMBOL(kretprobe_perf_func);
1202 #endif  /* CONFIG_PERF_EVENTS */
1203
1204 /*
1205  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1206  *
1207  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1208  * lockless, but we can't race with this __init function.
1209  */
1210 static int kprobe_register(struct ftrace_event_call *event,
1211                            enum trace_reg type, void *data)
1212 {
1213         struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1214         struct ftrace_event_file *file = data;
1215
1216         switch (type) {
1217         case TRACE_REG_REGISTER:
1218                 return enable_trace_kprobe(tk, file);
1219         case TRACE_REG_UNREGISTER:
1220                 return disable_trace_kprobe(tk, file);
1221
1222 #ifdef CONFIG_PERF_EVENTS
1223         case TRACE_REG_PERF_REGISTER:
1224                 return enable_trace_kprobe(tk, NULL);
1225         case TRACE_REG_PERF_UNREGISTER:
1226                 return disable_trace_kprobe(tk, NULL);
1227         case TRACE_REG_PERF_OPEN:
1228         case TRACE_REG_PERF_CLOSE:
1229         case TRACE_REG_PERF_ADD:
1230         case TRACE_REG_PERF_DEL:
1231                 return 0;
1232 #endif
1233         }
1234         return 0;
1235 }
1236
1237 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1238 {
1239         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1240
1241         tk->nhit++;
1242
1243         if (tk->tp.flags & TP_FLAG_TRACE)
1244                 kprobe_trace_func(tk, regs);
1245 #ifdef CONFIG_PERF_EVENTS
1246         if (tk->tp.flags & TP_FLAG_PROFILE)
1247                 kprobe_perf_func(tk, regs);
1248 #endif
1249         return 0;       /* We don't tweek kernel, so just return 0 */
1250 }
1251 NOKPROBE_SYMBOL(kprobe_dispatcher);
1252
1253 static int
1254 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1255 {
1256         struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1257
1258         tk->nhit++;
1259
1260         if (tk->tp.flags & TP_FLAG_TRACE)
1261                 kretprobe_trace_func(tk, ri, regs);
1262 #ifdef CONFIG_PERF_EVENTS
1263         if (tk->tp.flags & TP_FLAG_PROFILE)
1264                 kretprobe_perf_func(tk, ri, regs);
1265 #endif
1266         return 0;       /* We don't tweek kernel, so just return 0 */
1267 }
1268 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1269
1270 static struct trace_event_functions kretprobe_funcs = {
1271         .trace          = print_kretprobe_event
1272 };
1273
1274 static struct trace_event_functions kprobe_funcs = {
1275         .trace          = print_kprobe_event
1276 };
1277
1278 static int register_kprobe_event(struct trace_kprobe *tk)
1279 {
1280         struct ftrace_event_call *call = &tk->tp.call;
1281         int ret;
1282
1283         /* Initialize ftrace_event_call */
1284         INIT_LIST_HEAD(&call->class->fields);
1285         if (trace_kprobe_is_return(tk)) {
1286                 call->event.funcs = &kretprobe_funcs;
1287                 call->class->define_fields = kretprobe_event_define_fields;
1288         } else {
1289                 call->event.funcs = &kprobe_funcs;
1290                 call->class->define_fields = kprobe_event_define_fields;
1291         }
1292         if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1293                 return -ENOMEM;
1294         ret = register_ftrace_event(&call->event);
1295         if (!ret) {
1296                 kfree(call->print_fmt);
1297                 return -ENODEV;
1298         }
1299         call->flags = 0;
1300         call->class->reg = kprobe_register;
1301         call->data = tk;
1302         ret = trace_add_event_call(call);
1303         if (ret) {
1304                 pr_info("Failed to register kprobe event: %s\n",
1305                         ftrace_event_name(call));
1306                 kfree(call->print_fmt);
1307                 unregister_ftrace_event(&call->event);
1308         }
1309         return ret;
1310 }
1311
1312 static int unregister_kprobe_event(struct trace_kprobe *tk)
1313 {
1314         int ret;
1315
1316         /* tp->event is unregistered in trace_remove_event_call() */
1317         ret = trace_remove_event_call(&tk->tp.call);
1318         if (!ret)
1319                 kfree(tk->tp.call.print_fmt);
1320         return ret;
1321 }
1322
1323 /* Make a debugfs interface for controlling probe points */
1324 static __init int init_kprobe_trace(void)
1325 {
1326         struct dentry *d_tracer;
1327         struct dentry *entry;
1328
1329         if (register_module_notifier(&trace_kprobe_module_nb))
1330                 return -EINVAL;
1331
1332         d_tracer = tracing_init_dentry();
1333         if (!d_tracer)
1334                 return 0;
1335
1336         entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
1337                                     NULL, &kprobe_events_ops);
1338
1339         /* Event list interface */
1340         if (!entry)
1341                 pr_warning("Could not create debugfs "
1342                            "'kprobe_events' entry\n");
1343
1344         /* Profile interface */
1345         entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
1346                                     NULL, &kprobe_profile_ops);
1347
1348         if (!entry)
1349                 pr_warning("Could not create debugfs "
1350                            "'kprobe_profile' entry\n");
1351         return 0;
1352 }
1353 fs_initcall(init_kprobe_trace);
1354
1355
1356 #ifdef CONFIG_FTRACE_STARTUP_TEST
1357
1358 /*
1359  * The "__used" keeps gcc from removing the function symbol
1360  * from the kallsyms table.
1361  */
1362 static __used int kprobe_trace_selftest_target(int a1, int a2, int a3,
1363                                                int a4, int a5, int a6)
1364 {
1365         return a1 + a2 + a3 + a4 + a5 + a6;
1366 }
1367
1368 static struct ftrace_event_file *
1369 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1370 {
1371         struct ftrace_event_file *file;
1372
1373         list_for_each_entry(file, &tr->events, list)
1374                 if (file->event_call == &tk->tp.call)
1375                         return file;
1376
1377         return NULL;
1378 }
1379
1380 /*
1381  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1382  * stage, we can do this lockless.
1383  */
1384 static __init int kprobe_trace_self_tests_init(void)
1385 {
1386         int ret, warn = 0;
1387         int (*target)(int, int, int, int, int, int);
1388         struct trace_kprobe *tk;
1389         struct ftrace_event_file *file;
1390
1391         if (tracing_is_disabled())
1392                 return -ENODEV;
1393
1394         target = kprobe_trace_selftest_target;
1395
1396         pr_info("Testing kprobe tracing: ");
1397
1398         ret = traceprobe_command("p:testprobe kprobe_trace_selftest_target "
1399                                   "$stack $stack0 +0($stack)",
1400                                   create_trace_kprobe);
1401         if (WARN_ON_ONCE(ret)) {
1402                 pr_warn("error on probing function entry.\n");
1403                 warn++;
1404         } else {
1405                 /* Enable trace point */
1406                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1407                 if (WARN_ON_ONCE(tk == NULL)) {
1408                         pr_warn("error on getting new probe.\n");
1409                         warn++;
1410                 } else {
1411                         file = find_trace_probe_file(tk, top_trace_array());
1412                         if (WARN_ON_ONCE(file == NULL)) {
1413                                 pr_warn("error on getting probe file.\n");
1414                                 warn++;
1415                         } else
1416                                 enable_trace_kprobe(tk, file);
1417                 }
1418         }
1419
1420         ret = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target "
1421                                   "$retval", create_trace_kprobe);
1422         if (WARN_ON_ONCE(ret)) {
1423                 pr_warn("error on probing function return.\n");
1424                 warn++;
1425         } else {
1426                 /* Enable trace point */
1427                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1428                 if (WARN_ON_ONCE(tk == NULL)) {
1429                         pr_warn("error on getting 2nd new probe.\n");
1430                         warn++;
1431                 } else {
1432                         file = find_trace_probe_file(tk, top_trace_array());
1433                         if (WARN_ON_ONCE(file == NULL)) {
1434                                 pr_warn("error on getting probe file.\n");
1435                                 warn++;
1436                         } else
1437                                 enable_trace_kprobe(tk, file);
1438                 }
1439         }
1440
1441         if (warn)
1442                 goto end;
1443
1444         ret = target(1, 2, 3, 4, 5, 6);
1445
1446         /* Disable trace points before removing it */
1447         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1448         if (WARN_ON_ONCE(tk == NULL)) {
1449                 pr_warn("error on getting test probe.\n");
1450                 warn++;
1451         } else {
1452                 file = find_trace_probe_file(tk, top_trace_array());
1453                 if (WARN_ON_ONCE(file == NULL)) {
1454                         pr_warn("error on getting probe file.\n");
1455                         warn++;
1456                 } else
1457                         disable_trace_kprobe(tk, file);
1458         }
1459
1460         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1461         if (WARN_ON_ONCE(tk == NULL)) {
1462                 pr_warn("error on getting 2nd test probe.\n");
1463                 warn++;
1464         } else {
1465                 file = find_trace_probe_file(tk, top_trace_array());
1466                 if (WARN_ON_ONCE(file == NULL)) {
1467                         pr_warn("error on getting probe file.\n");
1468                         warn++;
1469                 } else
1470                         disable_trace_kprobe(tk, file);
1471         }
1472
1473         ret = traceprobe_command("-:testprobe", create_trace_kprobe);
1474         if (WARN_ON_ONCE(ret)) {
1475                 pr_warn("error on deleting a probe.\n");
1476                 warn++;
1477         }
1478
1479         ret = traceprobe_command("-:testprobe2", create_trace_kprobe);
1480         if (WARN_ON_ONCE(ret)) {
1481                 pr_warn("error on deleting a probe.\n");
1482                 warn++;
1483         }
1484
1485 end:
1486         release_all_trace_kprobes();
1487         if (warn)
1488                 pr_cont("NG: Some tests are failed. Please check them.\n");
1489         else
1490                 pr_cont("OK\n");
1491         return 0;
1492 }
1493
1494 late_initcall(kprobe_trace_self_tests_init);
1495
1496 #endif