kernel/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 static 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                                                 kprobes_fetch_type_table);
 765                 if (ret) {
 766                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
 767                         goto error;
 768                 }
 769         }
 770
 771         ret = register_trace_kprobe(tk);
 772         if (ret)
 773                 goto error;
 774         return 0;
 775
 776 error:
 777         free_trace_kprobe(tk);
 778         return ret;
 779 }
 780
 781 static int release_all_trace_kprobes(void)
 782 {
 783         struct trace_kprobe *tk;
 784         int ret = 0;
 785
 786         mutex_lock(&probe_lock);
 787         /* Ensure no probe is in use. */
 788         list_for_each_entry(tk, &probe_list, list)
 789                 if (trace_probe_is_enabled(&tk->tp)) {
 790                         ret = -EBUSY;
 791                         goto end;
 792                 }
 793         /* TODO: Use batch unregistration */
 794         while (!list_empty(&probe_list)) {
 795                 tk = list_entry(probe_list.next, struct trace_kprobe, list);
 796                 ret = unregister_trace_kprobe(tk);
 797                 if (ret)
 798                         goto end;
 799                 free_trace_kprobe(tk);
 800         }
 801
 802 end:
 803         mutex_unlock(&probe_lock);
 804
 805         return ret;
 806 }
 807
 808 /* Probes listing interfaces */
 809 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
 810 {
 811         mutex_lock(&probe_lock);
 812         return seq_list_start(&probe_list, *pos);
 813 }
 814
 815 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
 816 {
 817         return seq_list_next(v, &probe_list, pos);
 818 }
 819
 820 static void probes_seq_stop(struct seq_file *m, void *v)
 821 {
 822         mutex_unlock(&probe_lock);
 823 }
 824
 825 static int probes_seq_show(struct seq_file *m, void *v)
 826 {
 827         struct trace_kprobe *tk = v;
 828         int i;
 829
 830         seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
 831         seq_printf(m, ":%s/%s", tk->tp.call.class->system,
 832                         ftrace_event_name(&tk->tp.call));
 833
 834         if (!tk->symbol)
 835                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
 836         else if (tk->rp.kp.offset)
 837                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
 838                            tk->rp.kp.offset);
 839         else
 840                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
 841
 842         for (i = 0; i < tk->tp.nr_args; i++)
 843                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
 844         seq_putc(m, '\n');
 845
 846         return 0;
 847 }
 848
 849 static const struct seq_operations probes_seq_op = {
 850         .start  = probes_seq_start,
 851         .next   = probes_seq_next,
 852         .stop   = probes_seq_stop,
 853         .show   = probes_seq_show
 854 };
 855
 856 static int probes_open(struct inode *inode, struct file *file)
 857 {
 858         int ret;
 859
 860         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
 861                 ret = release_all_trace_kprobes();
 862                 if (ret < 0)
 863                         return ret;
 864         }
 865
 866         return seq_open(file, &probes_seq_op);
 867 }
 868
 869 static ssize_t probes_write(struct file *file, const char __user *buffer,
 870                             size_t count, loff_t *ppos)
 871 {
 872         return traceprobe_probes_write(file, buffer, count, ppos,
 873                         create_trace_kprobe);
 874 }
 875
 876 static const struct file_operations kprobe_events_ops = {
 877         .owner          = THIS_MODULE,
 878         .open           = probes_open,
 879         .read           = seq_read,
 880         .llseek         = seq_lseek,
 881         .release        = seq_release,
 882         .write          = probes_write,
 883 };
 884
 885 /* Probes profiling interfaces */
 886 static int probes_profile_seq_show(struct seq_file *m, void *v)
 887 {
 888         struct trace_kprobe *tk = v;
 889
 890         seq_printf(m, "  %-44s %15lu %15lu\n",
 891                    ftrace_event_name(&tk->tp.call), tk->nhit,
 892                    tk->rp.kp.nmissed);
 893
 894         return 0;
 895 }
 896
 897 static const struct seq_operations profile_seq_op = {
 898         .start  = probes_seq_start,
 899         .next   = probes_seq_next,
 900         .stop   = probes_seq_stop,
 901         .show   = probes_profile_seq_show
 902 };
 903
 904 static int profile_open(struct inode *inode, struct file *file)
 905 {
 906         return seq_open(file, &profile_seq_op);
 907 }
 908
 909 static const struct file_operations kprobe_profile_ops = {
 910         .owner          = THIS_MODULE,
 911         .open           = profile_open,
 912         .read           = seq_read,
 913         .llseek         = seq_lseek,
 914         .release        = seq_release,
 915 };
 916
 917 /* Kprobe handler */
 918 static nokprobe_inline void
 919 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
 920                     struct ftrace_event_file *ftrace_file)
 921 {
 922         struct kprobe_trace_entry_head *entry;
 923         struct ring_buffer_event *event;
 924         struct ring_buffer *buffer;
 925         int size, dsize, pc;
 926         unsigned long irq_flags;
 927         struct ftrace_event_call *call = &tk->tp.call;
 928
 929         WARN_ON(call != ftrace_file->event_call);
 930
 931         if (ftrace_trigger_soft_disabled(ftrace_file))
 932                 return;
 933
 934         local_save_flags(irq_flags);
 935         pc = preempt_count();
 936
 937         dsize = __get_data_size(&tk->tp, regs);
 938         size = sizeof(*entry) + tk->tp.size + dsize;
 939
 940         event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,
 941                                                 call->event.type,
 942                                                 size, irq_flags, pc);
 943         if (!event)
 944                 return;
 945
 946         entry = ring_buffer_event_data(event);
 947         entry->ip = (unsigned long)tk->rp.kp.addr;
 948         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
 949
 950         event_trigger_unlock_commit_regs(ftrace_file, buffer, event,
 951                                          entry, irq_flags, pc, regs);
 952 }
 953
 954 static void
 955 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
 956 {
 957         struct event_file_link *link;
 958
 959         list_for_each_entry_rcu(link, &tk->tp.files, list)
 960                 __kprobe_trace_func(tk, regs, link->file);
 961 }
 962 NOKPROBE_SYMBOL(kprobe_trace_func);
 963
 964 /* Kretprobe handler */
 965 static nokprobe_inline void
 966 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
 967                        struct pt_regs *regs,
 968                        struct ftrace_event_file *ftrace_file)
 969 {
 970         struct kretprobe_trace_entry_head *entry;
 971         struct ring_buffer_event *event;
 972         struct ring_buffer *buffer;
 973         int size, pc, dsize;
 974         unsigned long irq_flags;
 975         struct ftrace_event_call *call = &tk->tp.call;
 976
 977         WARN_ON(call != ftrace_file->event_call);
 978
 979         if (ftrace_trigger_soft_disabled(ftrace_file))
 980                 return;
 981
 982         local_save_flags(irq_flags);
 983         pc = preempt_count();
 984
 985         dsize = __get_data_size(&tk->tp, regs);
 986         size = sizeof(*entry) + tk->tp.size + dsize;
 987
 988         event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,
 989                                                 call->event.type,
 990                                                 size, irq_flags, pc);
 991         if (!event)
 992                 return;
 993
 994         entry = ring_buffer_event_data(event);
 995         entry->func = (unsigned long)tk->rp.kp.addr;
 996         entry->ret_ip = (unsigned long)ri->ret_addr;
 997         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
 998
 999         event_trigger_unlock_commit_regs(ftrace_file, buffer, event,
1000                                          entry, irq_flags, pc, regs);
1001 }
1002
1003 static void
1004 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1005                      struct pt_regs *regs)
1006 {
1007         struct event_file_link *link;
1008
1009         list_for_each_entry_rcu(link, &tk->tp.files, list)
1010                 __kretprobe_trace_func(tk, ri, regs, link->file);
1011 }
1012 NOKPROBE_SYMBOL(kretprobe_trace_func);
1013
1014 /* Event entry printers */
1015 static enum print_line_t
1016 print_kprobe_event(struct trace_iterator *iter, int flags,
1017                    struct trace_event *event)
1018 {
1019         struct kprobe_trace_entry_head *field;
1020         struct trace_seq *s = &iter->seq;
1021         struct trace_probe *tp;
1022         u8 *data;
1023         int i;
1024
1025         field = (struct kprobe_trace_entry_head *)iter->ent;
1026         tp = container_of(event, struct trace_probe, call.event);
1027
1028         trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call));
1029
1030         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1031                 goto out;
1032
1033         trace_seq_putc(s, ')');
1034
1035         data = (u8 *)&field[1];
1036         for (i = 0; i < tp->nr_args; i++)
1037                 if (!tp->args[i].type->print(s, tp->args[i].name,
1038                                              data + tp->args[i].offset, field))
1039                         goto out;
1040
1041         trace_seq_putc(s, '\n');
1042  out:
1043         return trace_handle_return(s);
1044 }
1045
1046 static enum print_line_t
1047 print_kretprobe_event(struct trace_iterator *iter, int flags,
1048                       struct trace_event *event)
1049 {
1050         struct kretprobe_trace_entry_head *field;
1051         struct trace_seq *s = &iter->seq;
1052         struct trace_probe *tp;
1053         u8 *data;
1054         int i;
1055
1056         field = (struct kretprobe_trace_entry_head *)iter->ent;
1057         tp = container_of(event, struct trace_probe, call.event);
1058
1059         trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call));
1060
1061         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1062                 goto out;
1063
1064         trace_seq_puts(s, " <- ");
1065
1066         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1067                 goto out;
1068
1069         trace_seq_putc(s, ')');
1070
1071         data = (u8 *)&field[1];
1072         for (i = 0; i < tp->nr_args; i++)
1073                 if (!tp->args[i].type->print(s, tp->args[i].name,
1074                                              data + tp->args[i].offset, field))
1075                         goto out;
1076
1077         trace_seq_putc(s, '\n');
1078
1079  out:
1080         return trace_handle_return(s);
1081 }
1082
1083
1084 static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1085 {
1086         int ret, i;
1087         struct kprobe_trace_entry_head field;
1088         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1089
1090         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1091         /* Set argument names as fields */
1092         for (i = 0; i < tk->tp.nr_args; i++) {
1093                 struct probe_arg *parg = &tk->tp.args[i];
1094
1095                 ret = trace_define_field(event_call, parg->type->fmttype,
1096                                          parg->name,
1097                                          sizeof(field) + parg->offset,
1098                                          parg->type->size,
1099                                          parg->type->is_signed,
1100                                          FILTER_OTHER);
1101                 if (ret)
1102                         return ret;
1103         }
1104         return 0;
1105 }
1106
1107 static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1108 {
1109         int ret, i;
1110         struct kretprobe_trace_entry_head field;
1111         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1112
1113         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1114         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1115         /* Set argument names as fields */
1116         for (i = 0; i < tk->tp.nr_args; i++) {
1117                 struct probe_arg *parg = &tk->tp.args[i];
1118
1119                 ret = trace_define_field(event_call, parg->type->fmttype,
1120                                          parg->name,
1121                                          sizeof(field) + parg->offset,
1122                                          parg->type->size,
1123                                          parg->type->is_signed,
1124                                          FILTER_OTHER);
1125                 if (ret)
1126                         return ret;
1127         }
1128         return 0;
1129 }
1130
1131 #ifdef CONFIG_PERF_EVENTS
1132
1133 /* Kprobe profile handler */
1134 static void
1135 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1136 {
1137         struct ftrace_event_call *call = &tk->tp.call;
1138         struct bpf_prog *prog = call->prog;
1139         struct kprobe_trace_entry_head *entry;
1140         struct hlist_head *head;
1141         int size, __size, dsize;
1142         int rctx;
1143
1144         if (prog && !trace_call_bpf(prog, regs))
1145                 return;
1146
1147         head = this_cpu_ptr(call->perf_events);
1148         if (hlist_empty(head))
1149                 return;
1150
1151         dsize = __get_data_size(&tk->tp, regs);
1152         __size = sizeof(*entry) + tk->tp.size + dsize;
1153         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1154         size -= sizeof(u32);
1155
1156         entry = perf_trace_buf_prepare(size, call->event.type, NULL, &rctx);
1157         if (!entry)
1158                 return;
1159
1160         entry->ip = (unsigned long)tk->rp.kp.addr;
1161         memset(&entry[1], 0, dsize);
1162         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1163         perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1164 }
1165 NOKPROBE_SYMBOL(kprobe_perf_func);
1166
1167 /* Kretprobe profile handler */
1168 static void
1169 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1170                     struct pt_regs *regs)
1171 {
1172         struct ftrace_event_call *call = &tk->tp.call;
1173         struct bpf_prog *prog = call->prog;
1174         struct kretprobe_trace_entry_head *entry;
1175         struct hlist_head *head;
1176         int size, __size, dsize;
1177         int rctx;
1178
1179         if (prog && !trace_call_bpf(prog, regs))
1180                 return;
1181
1182         head = this_cpu_ptr(call->perf_events);
1183         if (hlist_empty(head))
1184                 return;
1185
1186         dsize = __get_data_size(&tk->tp, regs);
1187         __size = sizeof(*entry) + tk->tp.size + dsize;
1188         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1189         size -= sizeof(u32);
1190
1191         entry = perf_trace_buf_prepare(size, call->event.type, NULL, &rctx);
1192         if (!entry)
1193                 return;
1194
1195         entry->func = (unsigned long)tk->rp.kp.addr;
1196         entry->ret_ip = (unsigned long)ri->ret_addr;
1197         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1198         perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1199 }
1200 NOKPROBE_SYMBOL(kretprobe_perf_func);
1201 #endif  /* CONFIG_PERF_EVENTS */
1202
1203 /*
1204  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1205  *
1206  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1207  * lockless, but we can't race with this __init function.
1208  */
1209 static int kprobe_register(struct ftrace_event_call *event,
1210                            enum trace_reg type, void *data)
1211 {
1212         struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1213         struct ftrace_event_file *file = data;
1214
1215         switch (type) {
1216         case TRACE_REG_REGISTER:
1217                 return enable_trace_kprobe(tk, file);
1218         case TRACE_REG_UNREGISTER:
1219                 return disable_trace_kprobe(tk, file);
1220
1221 #ifdef CONFIG_PERF_EVENTS
1222         case TRACE_REG_PERF_REGISTER:
1223                 return enable_trace_kprobe(tk, NULL);
1224         case TRACE_REG_PERF_UNREGISTER:
1225                 return disable_trace_kprobe(tk, NULL);
1226         case TRACE_REG_PERF_OPEN:
1227         case TRACE_REG_PERF_CLOSE:
1228         case TRACE_REG_PERF_ADD:
1229         case TRACE_REG_PERF_DEL:
1230                 return 0;
1231 #endif
1232         }
1233         return 0;
1234 }
1235
1236 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1237 {
1238         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1239
1240         tk->nhit++;
1241
1242         if (tk->tp.flags & TP_FLAG_TRACE)
1243                 kprobe_trace_func(tk, regs);
1244 #ifdef CONFIG_PERF_EVENTS
1245         if (tk->tp.flags & TP_FLAG_PROFILE)
1246                 kprobe_perf_func(tk, regs);
1247 #endif
1248         return 0;       /* We don't tweek kernel, so just return 0 */
1249 }
1250 NOKPROBE_SYMBOL(kprobe_dispatcher);
1251
1252 static int
1253 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1254 {
1255         struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1256
1257         tk->nhit++;
1258
1259         if (tk->tp.flags & TP_FLAG_TRACE)
1260                 kretprobe_trace_func(tk, ri, regs);
1261 #ifdef CONFIG_PERF_EVENTS
1262         if (tk->tp.flags & TP_FLAG_PROFILE)
1263                 kretprobe_perf_func(tk, ri, regs);
1264 #endif
1265         return 0;       /* We don't tweek kernel, so just return 0 */
1266 }
1267 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1268
1269 static struct trace_event_functions kretprobe_funcs = {
1270         .trace          = print_kretprobe_event
1271 };
1272
1273 static struct trace_event_functions kprobe_funcs = {
1274         .trace          = print_kprobe_event
1275 };
1276
1277 static int register_kprobe_event(struct trace_kprobe *tk)
1278 {
1279         struct ftrace_event_call *call = &tk->tp.call;
1280         int ret;
1281
1282         /* Initialize ftrace_event_call */
1283         INIT_LIST_HEAD(&call->class->fields);
1284         if (trace_kprobe_is_return(tk)) {
1285                 call->event.funcs = &kretprobe_funcs;
1286                 call->class->define_fields = kretprobe_event_define_fields;
1287         } else {
1288                 call->event.funcs = &kprobe_funcs;
1289                 call->class->define_fields = kprobe_event_define_fields;
1290         }
1291         if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1292                 return -ENOMEM;
1293         ret = register_ftrace_event(&call->event);
1294         if (!ret) {
1295                 kfree(call->print_fmt);
1296                 return -ENODEV;
1297         }
1298         call->flags = TRACE_EVENT_FL_KPROBE;
1299         call->class->reg = kprobe_register;
1300         call->data = tk;
1301         ret = trace_add_event_call(call);
1302         if (ret) {
1303                 pr_info("Failed to register kprobe event: %s\n",
1304                         ftrace_event_name(call));
1305                 kfree(call->print_fmt);
1306                 unregister_ftrace_event(&call->event);
1307         }
1308         return ret;
1309 }
1310
1311 static int unregister_kprobe_event(struct trace_kprobe *tk)
1312 {
1313         int ret;
1314
1315         /* tp->event is unregistered in trace_remove_event_call() */
1316         ret = trace_remove_event_call(&tk->tp.call);
1317         if (!ret)
1318                 kfree(tk->tp.call.print_fmt);
1319         return ret;
1320 }
1321
1322 /* Make a tracefs interface for controlling probe points */
1323 static __init int init_kprobe_trace(void)
1324 {
1325         struct dentry *d_tracer;
1326         struct dentry *entry;
1327
1328         if (register_module_notifier(&trace_kprobe_module_nb))
1329                 return -EINVAL;
1330
1331         d_tracer = tracing_init_dentry();
1332         if (IS_ERR(d_tracer))
1333                 return 0;
1334
1335         entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1336                                     NULL, &kprobe_events_ops);
1337
1338         /* Event list interface */
1339         if (!entry)
1340                 pr_warning("Could not create tracefs "
1341                            "'kprobe_events' entry\n");
1342
1343         /* Profile interface */
1344         entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1345                                     NULL, &kprobe_profile_ops);
1346
1347         if (!entry)
1348                 pr_warning("Could not create tracefs "
1349                            "'kprobe_profile' entry\n");
1350         return 0;
1351 }
1352 fs_initcall(init_kprobe_trace);
1353
1354
1355 #ifdef CONFIG_FTRACE_STARTUP_TEST
1356
1357 /*
1358  * The "__used" keeps gcc from removing the function symbol
1359  * from the kallsyms table.
1360  */
1361 static __used int kprobe_trace_selftest_target(int a1, int a2, int a3,
1362                                                int a4, int a5, int a6)
1363 {
1364         return a1 + a2 + a3 + a4 + a5 + a6;
1365 }
1366
1367 static struct ftrace_event_file *
1368 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1369 {
1370         struct ftrace_event_file *file;
1371
1372         list_for_each_entry(file, &tr->events, list)
1373                 if (file->event_call == &tk->tp.call)
1374                         return file;
1375
1376         return NULL;
1377 }
1378
1379 /*
1380  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1381  * stage, we can do this lockless.
1382  */
1383 static __init int kprobe_trace_self_tests_init(void)
1384 {
1385         int ret, warn = 0;
1386         int (*target)(int, int, int, int, int, int);
1387         struct trace_kprobe *tk;
1388         struct ftrace_event_file *file;
1389
1390         if (tracing_is_disabled())
1391                 return -ENODEV;
1392
1393         target = kprobe_trace_selftest_target;
1394
1395         pr_info("Testing kprobe tracing: ");
1396
1397         ret = traceprobe_command("p:testprobe kprobe_trace_selftest_target "
1398                                   "$stack $stack0 +0($stack)",
1399                                   create_trace_kprobe);
1400         if (WARN_ON_ONCE(ret)) {
1401                 pr_warn("error on probing function entry.\n");
1402                 warn++;
1403         } else {
1404                 /* Enable trace point */
1405                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1406                 if (WARN_ON_ONCE(tk == NULL)) {
1407                         pr_warn("error on getting new probe.\n");
1408                         warn++;
1409                 } else {
1410                         file = find_trace_probe_file(tk, top_trace_array());
1411                         if (WARN_ON_ONCE(file == NULL)) {
1412                                 pr_warn("error on getting probe file.\n");
1413                                 warn++;
1414                         } else
1415                                 enable_trace_kprobe(tk, file);
1416                 }
1417         }
1418
1419         ret = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target "
1420                                   "$retval", create_trace_kprobe);
1421         if (WARN_ON_ONCE(ret)) {
1422                 pr_warn("error on probing function return.\n");
1423                 warn++;
1424         } else {
1425                 /* Enable trace point */
1426                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1427                 if (WARN_ON_ONCE(tk == NULL)) {
1428                         pr_warn("error on getting 2nd new probe.\n");
1429                         warn++;
1430                 } else {
1431                         file = find_trace_probe_file(tk, top_trace_array());
1432                         if (WARN_ON_ONCE(file == NULL)) {
1433                                 pr_warn("error on getting probe file.\n");
1434                                 warn++;
1435                         } else
1436                                 enable_trace_kprobe(tk, file);
1437                 }
1438         }
1439
1440         if (warn)
1441                 goto end;
1442
1443         ret = target(1, 2, 3, 4, 5, 6);
1444
1445         /* Disable trace points before removing it */
1446         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1447         if (WARN_ON_ONCE(tk == NULL)) {
1448                 pr_warn("error on getting test probe.\n");
1449                 warn++;
1450         } else {
1451                 file = find_trace_probe_file(tk, top_trace_array());
1452                 if (WARN_ON_ONCE(file == NULL)) {
1453                         pr_warn("error on getting probe file.\n");
1454                         warn++;
1455                 } else
1456                         disable_trace_kprobe(tk, file);
1457         }
1458
1459         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1460         if (WARN_ON_ONCE(tk == NULL)) {
1461                 pr_warn("error on getting 2nd test probe.\n");
1462                 warn++;
1463         } else {
1464                 file = find_trace_probe_file(tk, top_trace_array());
1465                 if (WARN_ON_ONCE(file == NULL)) {
1466                         pr_warn("error on getting probe file.\n");
1467                         warn++;
1468                 } else
1469                         disable_trace_kprobe(tk, file);
1470         }
1471
1472         ret = traceprobe_command("-:testprobe", create_trace_kprobe);
1473         if (WARN_ON_ONCE(ret)) {
1474                 pr_warn("error on deleting a probe.\n");
1475                 warn++;
1476         }
1477
1478         ret = traceprobe_command("-:testprobe2", create_trace_kprobe);
1479         if (WARN_ON_ONCE(ret)) {
1480                 pr_warn("error on deleting a probe.\n");
1481                 warn++;
1482         }
1483
1484 end:
1485         release_all_trace_kprobes();
1486         if (warn)
1487                 pr_cont("NG: Some tests are failed. Please check them.\n");
1488         else
1489                 pr_cont("OK\n");
1490         return 0;
1491 }
1492
1493 late_initcall(kprobe_trace_self_tests_init);
1494
1495 #endif