Pileus Git - ~andy/linux/blob - 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 struct event_file_link {
  39         struct ftrace_event_file        *file;
  40         struct list_head                list;
  41 };
  42
  43 #define SIZEOF_TRACE_KPROBE(n)                          \
  44         (offsetof(struct trace_kprobe, tp.args) +       \
  45         (sizeof(struct probe_arg) * (n)))
  46
  47
  48 static __kprobes bool trace_kprobe_is_return(struct trace_kprobe *tk)
  49 {
  50         return tk->rp.handler != NULL;
  51 }
  52
  53 static __kprobes const char *trace_kprobe_symbol(struct trace_kprobe *tk)
  54 {
  55         return tk->symbol ? tk->symbol : "unknown";
  56 }
  57
  58 static __kprobes unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
  59 {
  60         return tk->rp.kp.offset;
  61 }
  62
  63 static __kprobes bool trace_kprobe_has_gone(struct trace_kprobe *tk)
  64 {
  65         return !!(kprobe_gone(&tk->rp.kp));
  66 }
  67
  68 static __kprobes bool trace_kprobe_within_module(struct trace_kprobe *tk,
  69                                                  struct module *mod)
  70 {
  71         int len = strlen(mod->name);
  72         const char *name = trace_kprobe_symbol(tk);
  73         return strncmp(mod->name, name, len) == 0 && name[len] == ':';
  74 }
  75
  76 static __kprobes bool trace_kprobe_is_on_module(struct trace_kprobe *tk)
  77 {
  78         return !!strchr(trace_kprobe_symbol(tk), ':');
  79 }
  80
  81 static int register_kprobe_event(struct trace_kprobe *tk);
  82 static int unregister_kprobe_event(struct trace_kprobe *tk);
  83
  84 static DEFINE_MUTEX(probe_lock);
  85 static LIST_HEAD(probe_list);
  86
  87 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
  88 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
  89                                 struct pt_regs *regs);
  90
  91 /* Memory fetching by symbol */
  92 struct symbol_cache {
  93         char            *symbol;
  94         long            offset;
  95         unsigned long   addr;
  96 };
  97
  98 unsigned long update_symbol_cache(struct symbol_cache *sc)
  99 {
 100         sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
 101
 102         if (sc->addr)
 103                 sc->addr += sc->offset;
 104
 105         return sc->addr;
 106 }
 107
 108 void free_symbol_cache(struct symbol_cache *sc)
 109 {
 110         kfree(sc->symbol);
 111         kfree(sc);
 112 }
 113
 114 struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
 115 {
 116         struct symbol_cache *sc;
 117
 118         if (!sym || strlen(sym) == 0)
 119                 return NULL;
 120
 121         sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
 122         if (!sc)
 123                 return NULL;
 124
 125         sc->symbol = kstrdup(sym, GFP_KERNEL);
 126         if (!sc->symbol) {
 127                 kfree(sc);
 128                 return NULL;
 129         }
 130         sc->offset = offset;
 131         update_symbol_cache(sc);
 132
 133         return sc;
 134 }
 135
 136 /*
 137  * Kprobes-specific fetch functions
 138  */
 139 #define DEFINE_FETCH_stack(type)                                        \
 140 static __kprobes void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,\
 141                                           void *offset, void *dest)     \
 142 {                                                                       \
 143         *(type *)dest = (type)regs_get_kernel_stack_nth(regs,           \
 144                                 (unsigned int)((unsigned long)offset)); \
 145 }
 146 DEFINE_BASIC_FETCH_FUNCS(stack)
 147 /* No string on the stack entry */
 148 #define fetch_stack_string      NULL
 149 #define fetch_stack_string_size NULL
 150
 151 #define DEFINE_FETCH_memory(type)                                       \
 152 static __kprobes void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,\
 153                                           void *addr, void *dest)       \
 154 {                                                                       \
 155         type retval;                                                    \
 156         if (probe_kernel_address(addr, retval))                         \
 157                 *(type *)dest = 0;                                      \
 158         else                                                            \
 159                 *(type *)dest = retval;                                 \
 160 }
 161 DEFINE_BASIC_FETCH_FUNCS(memory)
 162 /*
 163  * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
 164  * length and relative data location.
 165  */
 166 static __kprobes void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
 167                                                       void *addr, void *dest)
 168 {
 169         long ret;
 170         int maxlen = get_rloc_len(*(u32 *)dest);
 171         u8 *dst = get_rloc_data(dest);
 172         u8 *src = addr;
 173         mm_segment_t old_fs = get_fs();
 174
 175         if (!maxlen)
 176                 return;
 177
 178         /*
 179          * Try to get string again, since the string can be changed while
 180          * probing.
 181          */
 182         set_fs(KERNEL_DS);
 183         pagefault_disable();
 184
 185         do
 186                 ret = __copy_from_user_inatomic(dst++, src++, 1);
 187         while (dst[-1] && ret == 0 && src - (u8 *)addr < maxlen);
 188
 189         dst[-1] = '\0';
 190         pagefault_enable();
 191         set_fs(old_fs);
 192
 193         if (ret < 0) {  /* Failed to fetch string */
 194                 ((u8 *)get_rloc_data(dest))[0] = '\0';
 195                 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
 196         } else {
 197                 *(u32 *)dest = make_data_rloc(src - (u8 *)addr,
 198                                               get_rloc_offs(*(u32 *)dest));
 199         }
 200 }
 201
 202 /* Return the length of string -- including null terminal byte */
 203 static __kprobes 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
 228 #define DEFINE_FETCH_symbol(type)                                       \
 229 __kprobes void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs,      \
 230                                           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 DEFINE_BASIC_FETCH_FUNCS(symbol)
 239 DEFINE_FETCH_symbol(string)
 240 DEFINE_FETCH_symbol(string_size)
 241
 242 /* kprobes don't support file_offset fetch methods */
 243 #define fetch_file_offset_u8            NULL
 244 #define fetch_file_offset_u16           NULL
 245 #define fetch_file_offset_u32           NULL
 246 #define fetch_file_offset_u64           NULL
 247 #define fetch_file_offset_string        NULL
 248 #define fetch_file_offset_string_size   NULL
 249
 250 /* Fetch type information table */
 251 const struct fetch_type kprobes_fetch_type_table[] = {
 252         /* Special types */
 253         [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
 254                                         sizeof(u32), 1, "__data_loc char[]"),
 255         [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
 256                                         string_size, sizeof(u32), 0, "u32"),
 257         /* Basic types */
 258         ASSIGN_FETCH_TYPE(u8,  u8,  0),
 259         ASSIGN_FETCH_TYPE(u16, u16, 0),
 260         ASSIGN_FETCH_TYPE(u32, u32, 0),
 261         ASSIGN_FETCH_TYPE(u64, u64, 0),
 262         ASSIGN_FETCH_TYPE(s8,  u8,  1),
 263         ASSIGN_FETCH_TYPE(s16, u16, 1),
 264         ASSIGN_FETCH_TYPE(s32, u32, 1),
 265         ASSIGN_FETCH_TYPE(s64, u64, 1),
 266
 267         ASSIGN_FETCH_TYPE_END
 268 };
 269
 270 /*
 271  * Allocate new trace_probe and initialize it (including kprobes).
 272  */
 273 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
 274                                              const char *event,
 275                                              void *addr,
 276                                              const char *symbol,
 277                                              unsigned long offs,
 278                                              int nargs, bool is_return)
 279 {
 280         struct trace_kprobe *tk;
 281         int ret = -ENOMEM;
 282
 283         tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
 284         if (!tk)
 285                 return ERR_PTR(ret);
 286
 287         if (symbol) {
 288                 tk->symbol = kstrdup(symbol, GFP_KERNEL);
 289                 if (!tk->symbol)
 290                         goto error;
 291                 tk->rp.kp.symbol_name = tk->symbol;
 292                 tk->rp.kp.offset = offs;
 293         } else
 294                 tk->rp.kp.addr = addr;
 295
 296         if (is_return)
 297                 tk->rp.handler = kretprobe_dispatcher;
 298         else
 299                 tk->rp.kp.pre_handler = kprobe_dispatcher;
 300
 301         if (!event || !is_good_name(event)) {
 302                 ret = -EINVAL;
 303                 goto error;
 304         }
 305
 306         tk->tp.call.class = &tk->tp.class;
 307         tk->tp.call.name = kstrdup(event, GFP_KERNEL);
 308         if (!tk->tp.call.name)
 309                 goto error;
 310
 311         if (!group || !is_good_name(group)) {
 312                 ret = -EINVAL;
 313                 goto error;
 314         }
 315
 316         tk->tp.class.system = kstrdup(group, GFP_KERNEL);
 317         if (!tk->tp.class.system)
 318                 goto error;
 319
 320         INIT_LIST_HEAD(&tk->list);
 321         INIT_LIST_HEAD(&tk->tp.files);
 322         return tk;
 323 error:
 324         kfree(tk->tp.call.name);
 325         kfree(tk->symbol);
 326         kfree(tk);
 327         return ERR_PTR(ret);
 328 }
 329
 330 static void free_trace_kprobe(struct trace_kprobe *tk)
 331 {
 332         int i;
 333
 334         for (i = 0; i < tk->tp.nr_args; i++)
 335                 traceprobe_free_probe_arg(&tk->tp.args[i]);
 336
 337         kfree(tk->tp.call.class->system);
 338         kfree(tk->tp.call.name);
 339         kfree(tk->symbol);
 340         kfree(tk);
 341 }
 342
 343 static struct trace_kprobe *find_trace_kprobe(const char *event,
 344                                               const char *group)
 345 {
 346         struct trace_kprobe *tk;
 347
 348         list_for_each_entry(tk, &probe_list, list)
 349                 if (strcmp(tk->tp.call.name, event) == 0 &&
 350                     strcmp(tk->tp.call.class->system, group) == 0)
 351                         return tk;
 352         return NULL;
 353 }
 354
 355 /*
 356  * Enable trace_probe
 357  * if the file is NULL, enable "perf" handler, or enable "trace" handler.
 358  */
 359 static int
 360 enable_trace_kprobe(struct trace_kprobe *tk, struct ftrace_event_file *file)
 361 {
 362         int ret = 0;
 363
 364         if (file) {
 365                 struct event_file_link *link;
 366
 367                 link = kmalloc(sizeof(*link), GFP_KERNEL);
 368                 if (!link) {
 369                         ret = -ENOMEM;
 370                         goto out;
 371                 }
 372
 373                 link->file = file;
 374                 list_add_tail_rcu(&link->list, &tk->tp.files);
 375
 376                 tk->tp.flags |= TP_FLAG_TRACE;
 377         } else
 378                 tk->tp.flags |= TP_FLAG_PROFILE;
 379
 380         if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
 381                 if (trace_kprobe_is_return(tk))
 382                         ret = enable_kretprobe(&tk->rp);
 383                 else
 384                         ret = enable_kprobe(&tk->rp.kp);
 385         }
 386  out:
 387         return ret;
 388 }
 389
 390 static struct event_file_link *
 391 find_event_file_link(struct trace_probe *tp, struct ftrace_event_file *file)
 392 {
 393         struct event_file_link *link;
 394
 395         list_for_each_entry(link, &tp->files, list)
 396                 if (link->file == file)
 397                         return link;
 398
 399         return NULL;
 400 }
 401
 402 /*
 403  * Disable trace_probe
 404  * if the file is NULL, disable "perf" handler, or disable "trace" handler.
 405  */
 406 static int
 407 disable_trace_kprobe(struct trace_kprobe *tk, struct ftrace_event_file *file)
 408 {
 409         struct event_file_link *link = NULL;
 410         int wait = 0;
 411         int ret = 0;
 412
 413         if (file) {
 414                 link = find_event_file_link(&tk->tp, file);
 415                 if (!link) {
 416                         ret = -EINVAL;
 417                         goto out;
 418                 }
 419
 420                 list_del_rcu(&link->list);
 421                 wait = 1;
 422                 if (!list_empty(&tk->tp.files))
 423                         goto out;
 424
 425                 tk->tp.flags &= ~TP_FLAG_TRACE;
 426         } else
 427                 tk->tp.flags &= ~TP_FLAG_PROFILE;
 428
 429         if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
 430                 if (trace_kprobe_is_return(tk))
 431                         disable_kretprobe(&tk->rp);
 432                 else
 433                         disable_kprobe(&tk->rp.kp);
 434                 wait = 1;
 435         }
 436  out:
 437         if (wait) {
 438                 /*
 439                  * Synchronize with kprobe_trace_func/kretprobe_trace_func
 440                  * to ensure disabled (all running handlers are finished).
 441                  * This is not only for kfree(), but also the caller,
 442                  * trace_remove_event_call() supposes it for releasing
 443                  * event_call related objects, which will be accessed in
 444                  * the kprobe_trace_func/kretprobe_trace_func.
 445                  */
 446                 synchronize_sched();
 447                 kfree(link);    /* Ignored if link == NULL */
 448         }
 449
 450         return ret;
 451 }
 452
 453 /* Internal register function - just handle k*probes and flags */
 454 static int __register_trace_kprobe(struct trace_kprobe *tk)
 455 {
 456         int i, ret;
 457
 458         if (trace_probe_is_registered(&tk->tp))
 459                 return -EINVAL;
 460
 461         for (i = 0; i < tk->tp.nr_args; i++)
 462                 traceprobe_update_arg(&tk->tp.args[i]);
 463
 464         /* Set/clear disabled flag according to tp->flag */
 465         if (trace_probe_is_enabled(&tk->tp))
 466                 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
 467         else
 468                 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 469
 470         if (trace_kprobe_is_return(tk))
 471                 ret = register_kretprobe(&tk->rp);
 472         else
 473                 ret = register_kprobe(&tk->rp.kp);
 474
 475         if (ret == 0)
 476                 tk->tp.flags |= TP_FLAG_REGISTERED;
 477         else {
 478                 pr_warning("Could not insert probe at %s+%lu: %d\n",
 479                            trace_kprobe_symbol(tk), trace_kprobe_offset(tk), ret);
 480                 if (ret == -ENOENT && trace_kprobe_is_on_module(tk)) {
 481                         pr_warning("This probe might be able to register after"
 482                                    "target module is loaded. Continue.\n");
 483                         ret = 0;
 484                 } else if (ret == -EILSEQ) {
 485                         pr_warning("Probing address(0x%p) is not an "
 486                                    "instruction boundary.\n",
 487                                    tk->rp.kp.addr);
 488                         ret = -EINVAL;
 489                 }
 490         }
 491
 492         return ret;
 493 }
 494
 495 /* Internal unregister function - just handle k*probes and flags */
 496 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
 497 {
 498         if (trace_probe_is_registered(&tk->tp)) {
 499                 if (trace_kprobe_is_return(tk))
 500                         unregister_kretprobe(&tk->rp);
 501                 else
 502                         unregister_kprobe(&tk->rp.kp);
 503                 tk->tp.flags &= ~TP_FLAG_REGISTERED;
 504                 /* Cleanup kprobe for reuse */
 505                 if (tk->rp.kp.symbol_name)
 506                         tk->rp.kp.addr = NULL;
 507         }
 508 }
 509
 510 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
 511 static int unregister_trace_kprobe(struct trace_kprobe *tk)
 512 {
 513         /* Enabled event can not be unregistered */
 514         if (trace_probe_is_enabled(&tk->tp))
 515                 return -EBUSY;
 516
 517         /* Will fail if probe is being used by ftrace or perf */
 518         if (unregister_kprobe_event(tk))
 519                 return -EBUSY;
 520
 521         __unregister_trace_kprobe(tk);
 522         list_del(&tk->list);
 523
 524         return 0;
 525 }
 526
 527 /* Register a trace_probe and probe_event */
 528 static int register_trace_kprobe(struct trace_kprobe *tk)
 529 {
 530         struct trace_kprobe *old_tk;
 531         int ret;
 532
 533         mutex_lock(&probe_lock);
 534
 535         /* Delete old (same name) event if exist */
 536         old_tk = find_trace_kprobe(tk->tp.call.name, tk->tp.call.class->system);
 537         if (old_tk) {
 538                 ret = unregister_trace_kprobe(old_tk);
 539                 if (ret < 0)
 540                         goto end;
 541                 free_trace_kprobe(old_tk);
 542         }
 543
 544         /* Register new event */
 545         ret = register_kprobe_event(tk);
 546         if (ret) {
 547                 pr_warning("Failed to register probe event(%d)\n", ret);
 548                 goto end;
 549         }
 550
 551         /* Register k*probe */
 552         ret = __register_trace_kprobe(tk);
 553         if (ret < 0)
 554                 unregister_kprobe_event(tk);
 555         else
 556                 list_add_tail(&tk->list, &probe_list);
 557
 558 end:
 559         mutex_unlock(&probe_lock);
 560         return ret;
 561 }
 562
 563 /* Module notifier call back, checking event on the module */
 564 static int trace_kprobe_module_callback(struct notifier_block *nb,
 565                                        unsigned long val, void *data)
 566 {
 567         struct module *mod = data;
 568         struct trace_kprobe *tk;
 569         int ret;
 570
 571         if (val != MODULE_STATE_COMING)
 572                 return NOTIFY_DONE;
 573
 574         /* Update probes on coming module */
 575         mutex_lock(&probe_lock);
 576         list_for_each_entry(tk, &probe_list, list) {
 577                 if (trace_kprobe_within_module(tk, mod)) {
 578                         /* Don't need to check busy - this should have gone. */
 579                         __unregister_trace_kprobe(tk);
 580                         ret = __register_trace_kprobe(tk);
 581                         if (ret)
 582                                 pr_warning("Failed to re-register probe %s on"
 583                                            "%s: %d\n",
 584                                            tk->tp.call.name, mod->name, ret);
 585                 }
 586         }
 587         mutex_unlock(&probe_lock);
 588
 589         return NOTIFY_DONE;
 590 }
 591
 592 static struct notifier_block trace_kprobe_module_nb = {
 593         .notifier_call = trace_kprobe_module_callback,
 594         .priority = 1   /* Invoked after kprobe module callback */
 595 };
 596
 597 static int create_trace_kprobe(int argc, char **argv)
 598 {
 599         /*
 600          * Argument syntax:
 601          *  - Add kprobe: p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
 602          *  - Add kretprobe: r[:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
 603          * Fetch args:
 604          *  $retval     : fetch return value
 605          *  $stack      : fetch stack address
 606          *  $stackN     : fetch Nth of stack (N:0-)
 607          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 608          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 609          *  %REG        : fetch register REG
 610          * Dereferencing memory fetch:
 611          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 612          * Alias name of args:
 613          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 614          * Type of args:
 615          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 616          */
 617         struct trace_kprobe *tk;
 618         int i, ret = 0;
 619         bool is_return = false, is_delete = false;
 620         char *symbol = NULL, *event = NULL, *group = NULL;
 621         char *arg;
 622         unsigned long offset = 0;
 623         void *addr = NULL;
 624         char buf[MAX_EVENT_NAME_LEN];
 625
 626         /* argc must be >= 1 */
 627         if (argv[0][0] == 'p')
 628                 is_return = false;
 629         else if (argv[0][0] == 'r')
 630                 is_return = true;
 631         else if (argv[0][0] == '-')
 632                 is_delete = true;
 633         else {
 634                 pr_info("Probe definition must be started with 'p', 'r' or"
 635                         " '-'.\n");
 636                 return -EINVAL;
 637         }
 638
 639         if (argv[0][1] == ':') {
 640                 event = &argv[0][2];
 641                 if (strchr(event, '/')) {
 642                         group = event;
 643                         event = strchr(group, '/') + 1;
 644                         event[-1] = '\0';
 645                         if (strlen(group) == 0) {
 646                                 pr_info("Group name is not specified\n");
 647                                 return -EINVAL;
 648                         }
 649                 }
 650                 if (strlen(event) == 0) {
 651                         pr_info("Event name is not specified\n");
 652                         return -EINVAL;
 653                 }
 654         }
 655         if (!group)
 656                 group = KPROBE_EVENT_SYSTEM;
 657
 658         if (is_delete) {
 659                 if (!event) {
 660                         pr_info("Delete command needs an event name.\n");
 661                         return -EINVAL;
 662                 }
 663                 mutex_lock(&probe_lock);
 664                 tk = find_trace_kprobe(event, group);
 665                 if (!tk) {
 666                         mutex_unlock(&probe_lock);
 667                         pr_info("Event %s/%s doesn't exist.\n", group, event);
 668                         return -ENOENT;
 669                 }
 670                 /* delete an event */
 671                 ret = unregister_trace_kprobe(tk);
 672                 if (ret == 0)
 673                         free_trace_kprobe(tk);
 674                 mutex_unlock(&probe_lock);
 675                 return ret;
 676         }
 677
 678         if (argc < 2) {
 679                 pr_info("Probe point is not specified.\n");
 680                 return -EINVAL;
 681         }
 682         if (isdigit(argv[1][0])) {
 683                 if (is_return) {
 684                         pr_info("Return probe point must be a symbol.\n");
 685                         return -EINVAL;
 686                 }
 687                 /* an address specified */
 688                 ret = kstrtoul(&argv[1][0], 0, (unsigned long *)&addr);
 689                 if (ret) {
 690                         pr_info("Failed to parse address.\n");
 691                         return ret;
 692                 }
 693         } else {
 694                 /* a symbol specified */
 695                 symbol = argv[1];
 696                 /* TODO: support .init module functions */
 697                 ret = traceprobe_split_symbol_offset(symbol, &offset);
 698                 if (ret) {
 699                         pr_info("Failed to parse symbol.\n");
 700                         return ret;
 701                 }
 702                 if (offset && is_return) {
 703                         pr_info("Return probe must be used without offset.\n");
 704                         return -EINVAL;
 705                 }
 706         }
 707         argc -= 2; argv += 2;
 708
 709         /* setup a probe */
 710         if (!event) {
 711                 /* Make a new event name */
 712                 if (symbol)
 713                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 714                                  is_return ? 'r' : 'p', symbol, offset);
 715                 else
 716                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 717                                  is_return ? 'r' : 'p', addr);
 718                 event = buf;
 719         }
 720         tk = alloc_trace_kprobe(group, event, addr, symbol, offset, argc,
 721                                is_return);
 722         if (IS_ERR(tk)) {
 723                 pr_info("Failed to allocate trace_probe.(%d)\n",
 724                         (int)PTR_ERR(tk));
 725                 return PTR_ERR(tk);
 726         }
 727
 728         /* parse arguments */
 729         ret = 0;
 730         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 731                 struct probe_arg *parg = &tk->tp.args[i];
 732
 733                 /* Increment count for freeing args in error case */
 734                 tk->tp.nr_args++;
 735
 736                 /* Parse argument name */
 737                 arg = strchr(argv[i], '=');
 738                 if (arg) {
 739                         *arg++ = '\0';
 740                         parg->name = kstrdup(argv[i], GFP_KERNEL);
 741                 } else {
 742                         arg = argv[i];
 743                         /* If argument name is omitted, set "argN" */
 744                         snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
 745                         parg->name = kstrdup(buf, GFP_KERNEL);
 746                 }
 747
 748                 if (!parg->name) {
 749                         pr_info("Failed to allocate argument[%d] name.\n", i);
 750                         ret = -ENOMEM;
 751                         goto error;
 752                 }
 753
 754                 if (!is_good_name(parg->name)) {
 755                         pr_info("Invalid argument[%d] name: %s\n",
 756                                 i, parg->name);
 757                         ret = -EINVAL;
 758                         goto error;
 759                 }
 760
 761                 if (traceprobe_conflict_field_name(parg->name,
 762                                                         tk->tp.args, i)) {
 763                         pr_info("Argument[%d] name '%s' conflicts with "
 764                                 "another field.\n", i, argv[i]);
 765                         ret = -EINVAL;
 766                         goto error;
 767                 }
 768
 769                 /* Parse fetch argument */
 770                 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
 771                                                 is_return, true);
 772                 if (ret) {
 773                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
 774                         goto error;
 775                 }
 776         }
 777
 778         ret = register_trace_kprobe(tk);
 779         if (ret)
 780                 goto error;
 781         return 0;
 782
 783 error:
 784         free_trace_kprobe(tk);
 785         return ret;
 786 }
 787
 788 static int release_all_trace_kprobes(void)
 789 {
 790         struct trace_kprobe *tk;
 791         int ret = 0;
 792
 793         mutex_lock(&probe_lock);
 794         /* Ensure no probe is in use. */
 795         list_for_each_entry(tk, &probe_list, list)
 796                 if (trace_probe_is_enabled(&tk->tp)) {
 797                         ret = -EBUSY;
 798                         goto end;
 799                 }
 800         /* TODO: Use batch unregistration */
 801         while (!list_empty(&probe_list)) {
 802                 tk = list_entry(probe_list.next, struct trace_kprobe, list);
 803                 ret = unregister_trace_kprobe(tk);
 804                 if (ret)
 805                         goto end;
 806                 free_trace_kprobe(tk);
 807         }
 808
 809 end:
 810         mutex_unlock(&probe_lock);
 811
 812         return ret;
 813 }
 814
 815 /* Probes listing interfaces */
 816 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
 817 {
 818         mutex_lock(&probe_lock);
 819         return seq_list_start(&probe_list, *pos);
 820 }
 821
 822 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
 823 {
 824         return seq_list_next(v, &probe_list, pos);
 825 }
 826
 827 static void probes_seq_stop(struct seq_file *m, void *v)
 828 {
 829         mutex_unlock(&probe_lock);
 830 }
 831
 832 static int probes_seq_show(struct seq_file *m, void *v)
 833 {
 834         struct trace_kprobe *tk = v;
 835         int i;
 836
 837         seq_printf(m, "%c", trace_kprobe_is_return(tk) ? 'r' : 'p');
 838         seq_printf(m, ":%s/%s", tk->tp.call.class->system, tk->tp.call.name);
 839
 840         if (!tk->symbol)
 841                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
 842         else if (tk->rp.kp.offset)
 843                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
 844                            tk->rp.kp.offset);
 845         else
 846                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
 847
 848         for (i = 0; i < tk->tp.nr_args; i++)
 849                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
 850         seq_printf(m, "\n");
 851
 852         return 0;
 853 }
 854
 855 static const struct seq_operations probes_seq_op = {
 856         .start  = probes_seq_start,
 857         .next   = probes_seq_next,
 858         .stop   = probes_seq_stop,
 859         .show   = probes_seq_show
 860 };
 861
 862 static int probes_open(struct inode *inode, struct file *file)
 863 {
 864         int ret;
 865
 866         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
 867                 ret = release_all_trace_kprobes();
 868                 if (ret < 0)
 869                         return ret;
 870         }
 871
 872         return seq_open(file, &probes_seq_op);
 873 }
 874
 875 static ssize_t probes_write(struct file *file, const char __user *buffer,
 876                             size_t count, loff_t *ppos)
 877 {
 878         return traceprobe_probes_write(file, buffer, count, ppos,
 879                         create_trace_kprobe);
 880 }
 881
 882 static const struct file_operations kprobe_events_ops = {
 883         .owner          = THIS_MODULE,
 884         .open           = probes_open,
 885         .read           = seq_read,
 886         .llseek         = seq_lseek,
 887         .release        = seq_release,
 888         .write          = probes_write,
 889 };
 890
 891 /* Probes profiling interfaces */
 892 static int probes_profile_seq_show(struct seq_file *m, void *v)
 893 {
 894         struct trace_kprobe *tk = v;
 895
 896         seq_printf(m, "  %-44s %15lu %15lu\n", tk->tp.call.name, tk->nhit,
 897                    tk->rp.kp.nmissed);
 898
 899         return 0;
 900 }
 901
 902 static const struct seq_operations profile_seq_op = {
 903         .start  = probes_seq_start,
 904         .next   = probes_seq_next,
 905         .stop   = probes_seq_stop,
 906         .show   = probes_profile_seq_show
 907 };
 908
 909 static int profile_open(struct inode *inode, struct file *file)
 910 {
 911         return seq_open(file, &profile_seq_op);
 912 }
 913
 914 static const struct file_operations kprobe_profile_ops = {
 915         .owner          = THIS_MODULE,
 916         .open           = profile_open,
 917         .read           = seq_read,
 918         .llseek         = seq_lseek,
 919         .release        = seq_release,
 920 };
 921
 922 /* Kprobe handler */
 923 static __kprobes void
 924 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
 925                     struct ftrace_event_file *ftrace_file)
 926 {
 927         struct kprobe_trace_entry_head *entry;
 928         struct ring_buffer_event *event;
 929         struct ring_buffer *buffer;
 930         int size, dsize, pc;
 931         unsigned long irq_flags;
 932         struct ftrace_event_call *call = &tk->tp.call;
 933
 934         WARN_ON(call != ftrace_file->event_call);
 935
 936         if (ftrace_trigger_soft_disabled(ftrace_file))
 937                 return;
 938
 939         local_save_flags(irq_flags);
 940         pc = preempt_count();
 941
 942         dsize = __get_data_size(&tk->tp, regs);
 943         size = sizeof(*entry) + tk->tp.size + dsize;
 944
 945         event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,
 946                                                 call->event.type,
 947                                                 size, irq_flags, pc);
 948         if (!event)
 949                 return;
 950
 951         entry = ring_buffer_event_data(event);
 952         entry->ip = (unsigned long)tk->rp.kp.addr;
 953         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
 954
 955         event_trigger_unlock_commit_regs(ftrace_file, buffer, event,
 956                                          entry, irq_flags, pc, regs);
 957 }
 958
 959 static __kprobes void
 960 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
 961 {
 962         struct event_file_link *link;
 963
 964         list_for_each_entry_rcu(link, &tk->tp.files, list)
 965                 __kprobe_trace_func(tk, regs, link->file);
 966 }
 967
 968 /* Kretprobe handler */
 969 static __kprobes void
 970 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
 971                        struct pt_regs *regs,
 972                        struct ftrace_event_file *ftrace_file)
 973 {
 974         struct kretprobe_trace_entry_head *entry;
 975         struct ring_buffer_event *event;
 976         struct ring_buffer *buffer;
 977         int size, pc, dsize;
 978         unsigned long irq_flags;
 979         struct ftrace_event_call *call = &tk->tp.call;
 980
 981         WARN_ON(call != ftrace_file->event_call);
 982
 983         if (ftrace_trigger_soft_disabled(ftrace_file))
 984                 return;
 985
 986         local_save_flags(irq_flags);
 987         pc = preempt_count();
 988
 989         dsize = __get_data_size(&tk->tp, regs);
 990         size = sizeof(*entry) + tk->tp.size + dsize;
 991
 992         event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,
 993                                                 call->event.type,
 994                                                 size, irq_flags, pc);
 995         if (!event)
 996                 return;
 997
 998         entry = ring_buffer_event_data(event);
 999         entry->func = (unsigned long)tk->rp.kp.addr;
1000         entry->ret_ip = (unsigned long)ri->ret_addr;
1001         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1002
1003         event_trigger_unlock_commit_regs(ftrace_file, buffer, event,
1004                                          entry, irq_flags, pc, regs);
1005 }
1006
1007 static __kprobes void
1008 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1009                      struct pt_regs *regs)
1010 {
1011         struct event_file_link *link;
1012
1013         list_for_each_entry_rcu(link, &tk->tp.files, list)
1014                 __kretprobe_trace_func(tk, ri, regs, link->file);
1015 }
1016
1017 /* Event entry printers */
1018 static enum print_line_t
1019 print_kprobe_event(struct trace_iterator *iter, int flags,
1020                    struct trace_event *event)
1021 {
1022         struct kprobe_trace_entry_head *field;
1023         struct trace_seq *s = &iter->seq;
1024         struct trace_probe *tp;
1025         u8 *data;
1026         int i;
1027
1028         field = (struct kprobe_trace_entry_head *)iter->ent;
1029         tp = container_of(event, struct trace_probe, call.event);
1030
1031         if (!trace_seq_printf(s, "%s: (", tp->call.name))
1032                 goto partial;
1033
1034         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1035                 goto partial;
1036
1037         if (!trace_seq_puts(s, ")"))
1038                 goto partial;
1039
1040         data = (u8 *)&field[1];
1041         for (i = 0; i < tp->nr_args; i++)
1042                 if (!tp->args[i].type->print(s, tp->args[i].name,
1043                                              data + tp->args[i].offset, field))
1044                         goto partial;
1045
1046         if (!trace_seq_puts(s, "\n"))
1047                 goto partial;
1048
1049         return TRACE_TYPE_HANDLED;
1050 partial:
1051         return TRACE_TYPE_PARTIAL_LINE;
1052 }
1053
1054 static enum print_line_t
1055 print_kretprobe_event(struct trace_iterator *iter, int flags,
1056                       struct trace_event *event)
1057 {
1058         struct kretprobe_trace_entry_head *field;
1059         struct trace_seq *s = &iter->seq;
1060         struct trace_probe *tp;
1061         u8 *data;
1062         int i;
1063
1064         field = (struct kretprobe_trace_entry_head *)iter->ent;
1065         tp = container_of(event, struct trace_probe, call.event);
1066
1067         if (!trace_seq_printf(s, "%s: (", tp->call.name))
1068                 goto partial;
1069
1070         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1071                 goto partial;
1072
1073         if (!trace_seq_puts(s, " <- "))
1074                 goto partial;
1075
1076         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1077                 goto partial;
1078
1079         if (!trace_seq_puts(s, ")"))
1080                 goto partial;
1081
1082         data = (u8 *)&field[1];
1083         for (i = 0; i < tp->nr_args; i++)
1084                 if (!tp->args[i].type->print(s, tp->args[i].name,
1085                                              data + tp->args[i].offset, field))
1086                         goto partial;
1087
1088         if (!trace_seq_puts(s, "\n"))
1089                 goto partial;
1090
1091         return TRACE_TYPE_HANDLED;
1092 partial:
1093         return TRACE_TYPE_PARTIAL_LINE;
1094 }
1095
1096
1097 static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1098 {
1099         int ret, i;
1100         struct kprobe_trace_entry_head field;
1101         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1102
1103         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1104         /* Set argument names as fields */
1105         for (i = 0; i < tk->tp.nr_args; i++) {
1106                 struct probe_arg *parg = &tk->tp.args[i];
1107
1108                 ret = trace_define_field(event_call, parg->type->fmttype,
1109                                          parg->name,
1110                                          sizeof(field) + parg->offset,
1111                                          parg->type->size,
1112                                          parg->type->is_signed,
1113                                          FILTER_OTHER);
1114                 if (ret)
1115                         return ret;
1116         }
1117         return 0;
1118 }
1119
1120 static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1121 {
1122         int ret, i;
1123         struct kretprobe_trace_entry_head field;
1124         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1125
1126         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1127         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1128         /* Set argument names as fields */
1129         for (i = 0; i < tk->tp.nr_args; i++) {
1130                 struct probe_arg *parg = &tk->tp.args[i];
1131
1132                 ret = trace_define_field(event_call, parg->type->fmttype,
1133                                          parg->name,
1134                                          sizeof(field) + parg->offset,
1135                                          parg->type->size,
1136                                          parg->type->is_signed,
1137                                          FILTER_OTHER);
1138                 if (ret)
1139                         return ret;
1140         }
1141         return 0;
1142 }
1143
1144 #ifdef CONFIG_PERF_EVENTS
1145
1146 /* Kprobe profile handler */
1147 static __kprobes void
1148 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1149 {
1150         struct ftrace_event_call *call = &tk->tp.call;
1151         struct kprobe_trace_entry_head *entry;
1152         struct hlist_head *head;
1153         int size, __size, dsize;
1154         int rctx;
1155
1156         head = this_cpu_ptr(call->perf_events);
1157         if (hlist_empty(head))
1158                 return;
1159
1160         dsize = __get_data_size(&tk->tp, regs);
1161         __size = sizeof(*entry) + tk->tp.size + dsize;
1162         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1163         size -= sizeof(u32);
1164
1165         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1166         if (!entry)
1167                 return;
1168
1169         entry->ip = (unsigned long)tk->rp.kp.addr;
1170         memset(&entry[1], 0, dsize);
1171         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1172         perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1173 }
1174
1175 /* Kretprobe profile handler */
1176 static __kprobes void
1177 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1178                     struct pt_regs *regs)
1179 {
1180         struct ftrace_event_call *call = &tk->tp.call;
1181         struct kretprobe_trace_entry_head *entry;
1182         struct hlist_head *head;
1183         int size, __size, dsize;
1184         int rctx;
1185
1186         head = this_cpu_ptr(call->perf_events);
1187         if (hlist_empty(head))
1188                 return;
1189
1190         dsize = __get_data_size(&tk->tp, regs);
1191         __size = sizeof(*entry) + tk->tp.size + dsize;
1192         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1193         size -= sizeof(u32);
1194
1195         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1196         if (!entry)
1197                 return;
1198
1199         entry->func = (unsigned long)tk->rp.kp.addr;
1200         entry->ret_ip = (unsigned long)ri->ret_addr;
1201         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1202         perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1203 }
1204 #endif  /* CONFIG_PERF_EVENTS */
1205
1206 /*
1207  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1208  *
1209  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1210  * lockless, but we can't race with this __init function.
1211  */
1212 static __kprobes
1213 int kprobe_register(struct ftrace_event_call *event,
1214                     enum trace_reg type, void *data)
1215 {
1216         struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1217         struct ftrace_event_file *file = data;
1218
1219         switch (type) {
1220         case TRACE_REG_REGISTER:
1221                 return enable_trace_kprobe(tk, file);
1222         case TRACE_REG_UNREGISTER:
1223                 return disable_trace_kprobe(tk, file);
1224
1225 #ifdef CONFIG_PERF_EVENTS
1226         case TRACE_REG_PERF_REGISTER:
1227                 return enable_trace_kprobe(tk, NULL);
1228         case TRACE_REG_PERF_UNREGISTER:
1229                 return disable_trace_kprobe(tk, NULL);
1230         case TRACE_REG_PERF_OPEN:
1231         case TRACE_REG_PERF_CLOSE:
1232         case TRACE_REG_PERF_ADD:
1233         case TRACE_REG_PERF_DEL:
1234                 return 0;
1235 #endif
1236         }
1237         return 0;
1238 }
1239
1240 static __kprobes
1241 int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1242 {
1243         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1244
1245         tk->nhit++;
1246
1247         if (tk->tp.flags & TP_FLAG_TRACE)
1248                 kprobe_trace_func(tk, regs);
1249 #ifdef CONFIG_PERF_EVENTS
1250         if (tk->tp.flags & TP_FLAG_PROFILE)
1251                 kprobe_perf_func(tk, regs);
1252 #endif
1253         return 0;       /* We don't tweek kernel, so just return 0 */
1254 }
1255
1256 static __kprobes
1257 int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1258 {
1259         struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1260
1261         tk->nhit++;
1262
1263         if (tk->tp.flags & TP_FLAG_TRACE)
1264                 kretprobe_trace_func(tk, ri, regs);
1265 #ifdef CONFIG_PERF_EVENTS
1266         if (tk->tp.flags & TP_FLAG_PROFILE)
1267                 kretprobe_perf_func(tk, ri, regs);
1268 #endif
1269         return 0;       /* We don't tweek kernel, so just return 0 */
1270 }
1271
1272 static struct trace_event_functions kretprobe_funcs = {
1273         .trace          = print_kretprobe_event
1274 };
1275
1276 static struct trace_event_functions kprobe_funcs = {
1277         .trace          = print_kprobe_event
1278 };
1279
1280 static int register_kprobe_event(struct trace_kprobe *tk)
1281 {
1282         struct ftrace_event_call *call = &tk->tp.call;
1283         int ret;
1284
1285         /* Initialize ftrace_event_call */
1286         INIT_LIST_HEAD(&call->class->fields);
1287         if (trace_kprobe_is_return(tk)) {
1288                 call->event.funcs = &kretprobe_funcs;
1289                 call->class->define_fields = kretprobe_event_define_fields;
1290         } else {
1291                 call->event.funcs = &kprobe_funcs;
1292                 call->class->define_fields = kprobe_event_define_fields;
1293         }
1294         if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1295                 return -ENOMEM;
1296         ret = register_ftrace_event(&call->event);
1297         if (!ret) {
1298                 kfree(call->print_fmt);
1299                 return -ENODEV;
1300         }
1301         call->flags = 0;
1302         call->class->reg = kprobe_register;
1303         call->data = tk;
1304         ret = trace_add_event_call(call);
1305         if (ret) {
1306                 pr_info("Failed to register kprobe event: %s\n", call->name);
1307                 kfree(call->print_fmt);
1308                 unregister_ftrace_event(&call->event);
1309         }
1310         return ret;
1311 }
1312
1313 static int unregister_kprobe_event(struct trace_kprobe *tk)
1314 {
1315         int ret;
1316
1317         /* tp->event is unregistered in trace_remove_event_call() */
1318         ret = trace_remove_event_call(&tk->tp.call);
1319         if (!ret)
1320                 kfree(tk->tp.call.print_fmt);
1321         return ret;
1322 }
1323
1324 /* Make a debugfs interface for controlling probe points */
1325 static __init int init_kprobe_trace(void)
1326 {
1327         struct dentry *d_tracer;
1328         struct dentry *entry;
1329
1330         if (register_module_notifier(&trace_kprobe_module_nb))
1331                 return -EINVAL;
1332
1333         d_tracer = tracing_init_dentry();
1334         if (!d_tracer)
1335                 return 0;
1336
1337         entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
1338                                     NULL, &kprobe_events_ops);
1339
1340         /* Event list interface */
1341         if (!entry)
1342                 pr_warning("Could not create debugfs "
1343                            "'kprobe_events' entry\n");
1344
1345         /* Profile interface */
1346         entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
1347                                     NULL, &kprobe_profile_ops);
1348
1349         if (!entry)
1350                 pr_warning("Could not create debugfs "
1351                            "'kprobe_profile' entry\n");
1352         return 0;
1353 }
1354 fs_initcall(init_kprobe_trace);
1355
1356
1357 #ifdef CONFIG_FTRACE_STARTUP_TEST
1358
1359 /*
1360  * The "__used" keeps gcc from removing the function symbol
1361  * from the kallsyms table.
1362  */
1363 static __used int kprobe_trace_selftest_target(int a1, int a2, int a3,
1364                                                int a4, int a5, int a6)
1365 {
1366         return a1 + a2 + a3 + a4 + a5 + a6;
1367 }
1368
1369 static struct ftrace_event_file *
1370 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1371 {
1372         struct ftrace_event_file *file;
1373
1374         list_for_each_entry(file, &tr->events, list)
1375                 if (file->event_call == &tk->tp.call)
1376                         return file;
1377
1378         return NULL;
1379 }
1380
1381 /*
1382  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1383  * stage, we can do this lockless.
1384  */
1385 static __init int kprobe_trace_self_tests_init(void)
1386 {
1387         int ret, warn = 0;
1388         int (*target)(int, int, int, int, int, int);
1389         struct trace_kprobe *tk;
1390         struct ftrace_event_file *file;
1391
1392         target = kprobe_trace_selftest_target;
1393
1394         pr_info("Testing kprobe tracing: ");
1395
1396         ret = traceprobe_command("p:testprobe kprobe_trace_selftest_target "
1397                                   "$stack $stack0 +0($stack)",
1398                                   create_trace_kprobe);
1399         if (WARN_ON_ONCE(ret)) {
1400                 pr_warn("error on probing function entry.\n");
1401                 warn++;
1402         } else {
1403                 /* Enable trace point */
1404                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1405                 if (WARN_ON_ONCE(tk == NULL)) {
1406                         pr_warn("error on getting new probe.\n");
1407                         warn++;
1408                 } else {
1409                         file = find_trace_probe_file(tk, top_trace_array());
1410                         if (WARN_ON_ONCE(file == NULL)) {
1411                                 pr_warn("error on getting probe file.\n");
1412                                 warn++;
1413                         } else
1414                                 enable_trace_kprobe(tk, file);
1415                 }
1416         }
1417
1418         ret = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target "
1419                                   "$retval", create_trace_kprobe);
1420         if (WARN_ON_ONCE(ret)) {
1421                 pr_warn("error on probing function return.\n");
1422                 warn++;
1423         } else {
1424                 /* Enable trace point */
1425                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1426                 if (WARN_ON_ONCE(tk == NULL)) {
1427                         pr_warn("error on getting 2nd new probe.\n");
1428                         warn++;
1429                 } else {
1430                         file = find_trace_probe_file(tk, top_trace_array());
1431                         if (WARN_ON_ONCE(file == NULL)) {
1432                                 pr_warn("error on getting probe file.\n");
1433                                 warn++;
1434                         } else
1435                                 enable_trace_kprobe(tk, file);
1436                 }
1437         }
1438
1439         if (warn)
1440                 goto end;
1441
1442         ret = target(1, 2, 3, 4, 5, 6);
1443
1444         /* Disable trace points before removing it */
1445         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1446         if (WARN_ON_ONCE(tk == NULL)) {
1447                 pr_warn("error on getting test probe.\n");
1448                 warn++;
1449         } else {
1450                 file = find_trace_probe_file(tk, top_trace_array());
1451                 if (WARN_ON_ONCE(file == NULL)) {
1452                         pr_warn("error on getting probe file.\n");
1453                         warn++;
1454                 } else
1455                         disable_trace_kprobe(tk, file);
1456         }
1457
1458         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1459         if (WARN_ON_ONCE(tk == NULL)) {
1460                 pr_warn("error on getting 2nd test probe.\n");
1461                 warn++;
1462         } else {
1463                 file = find_trace_probe_file(tk, top_trace_array());
1464                 if (WARN_ON_ONCE(file == NULL)) {
1465                         pr_warn("error on getting probe file.\n");
1466                         warn++;
1467                 } else
1468                         disable_trace_kprobe(tk, file);
1469         }
1470
1471         ret = traceprobe_command("-:testprobe", create_trace_kprobe);
1472         if (WARN_ON_ONCE(ret)) {
1473                 pr_warn("error on deleting a probe.\n");
1474                 warn++;
1475         }
1476
1477         ret = traceprobe_command("-:testprobe2", create_trace_kprobe);
1478         if (WARN_ON_ONCE(ret)) {
1479                 pr_warn("error on deleting a probe.\n");
1480                 warn++;
1481         }
1482
1483 end:
1484         release_all_trace_kprobes();
1485         if (warn)
1486                 pr_cont("NG: Some tests are failed. Please check them.\n");
1487         else
1488                 pr_cont("OK\n");
1489         return 0;
1490 }
1491
1492 late_initcall(kprobe_trace_self_tests_init);
1493
1494 #endif