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 __kprobes bool trace_kprobe_is_return(struct trace_kprobe *tk)
  44 {
  45         return tk->rp.handler != NULL;
  46 }
  47
  48 static __kprobes const char *trace_kprobe_symbol(struct trace_kprobe *tk)
  49 {
  50         return tk->symbol ? tk->symbol : "unknown";
  51 }
  52
  53 static __kprobes unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
  54 {
  55         return tk->rp.kp.offset;
  56 }
  57
  58 static __kprobes bool trace_kprobe_has_gone(struct trace_kprobe *tk)
  59 {
  60         return !!(kprobe_gone(&tk->rp.kp));
  61 }
  62
  63 static __kprobes 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 __kprobes 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 __kprobes 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 DEFINE_BASIC_FETCH_FUNCS(stack)
 142 /* No string on the stack entry */
 143 #define fetch_stack_string      NULL
 144 #define fetch_stack_string_size NULL
 145
 146 #define DEFINE_FETCH_memory(type)                                       \
 147 static __kprobes void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,\
 148                                           void *addr, void *dest)       \
 149 {                                                                       \
 150         type retval;                                                    \
 151         if (probe_kernel_address(addr, retval))                         \
 152                 *(type *)dest = 0;                                      \
 153         else                                                            \
 154                 *(type *)dest = retval;                                 \
 155 }
 156 DEFINE_BASIC_FETCH_FUNCS(memory)
 157 /*
 158  * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
 159  * length and relative data location.
 160  */
 161 static __kprobes void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
 162                                                       void *addr, void *dest)
 163 {
 164         long ret;
 165         int maxlen = get_rloc_len(*(u32 *)dest);
 166         u8 *dst = get_rloc_data(dest);
 167         u8 *src = addr;
 168         mm_segment_t old_fs = get_fs();
 169
 170         if (!maxlen)
 171                 return;
 172
 173         /*
 174          * Try to get string again, since the string can be changed while
 175          * probing.
 176          */
 177         set_fs(KERNEL_DS);
 178         pagefault_disable();
 179
 180         do
 181                 ret = __copy_from_user_inatomic(dst++, src++, 1);
 182         while (dst[-1] && ret == 0 && src - (u8 *)addr < maxlen);
 183
 184         dst[-1] = '\0';
 185         pagefault_enable();
 186         set_fs(old_fs);
 187
 188         if (ret < 0) {  /* Failed to fetch string */
 189                 ((u8 *)get_rloc_data(dest))[0] = '\0';
 190                 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
 191         } else {
 192                 *(u32 *)dest = make_data_rloc(src - (u8 *)addr,
 193                                               get_rloc_offs(*(u32 *)dest));
 194         }
 195 }
 196
 197 /* Return the length of string -- including null terminal byte */
 198 static __kprobes void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
 199                                                         void *addr, void *dest)
 200 {
 201         mm_segment_t old_fs;
 202         int ret, len = 0;
 203         u8 c;
 204
 205         old_fs = get_fs();
 206         set_fs(KERNEL_DS);
 207         pagefault_disable();
 208
 209         do {
 210                 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
 211                 len++;
 212         } while (c && ret == 0 && len < MAX_STRING_SIZE);
 213
 214         pagefault_enable();
 215         set_fs(old_fs);
 216
 217         if (ret < 0)    /* Failed to check the length */
 218                 *(u32 *)dest = 0;
 219         else
 220                 *(u32 *)dest = len;
 221 }
 222
 223 #define DEFINE_FETCH_symbol(type)                                       \
 224 __kprobes void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs,      \
 225                                           void *data, void *dest)       \
 226 {                                                                       \
 227         struct symbol_cache *sc = data;                                 \
 228         if (sc->addr)                                                   \
 229                 fetch_memory_##type(regs, (void *)sc->addr, dest);      \
 230         else                                                            \
 231                 *(type *)dest = 0;                                      \
 232 }
 233 DEFINE_BASIC_FETCH_FUNCS(symbol)
 234 DEFINE_FETCH_symbol(string)
 235 DEFINE_FETCH_symbol(string_size)
 236
 237 /* kprobes don't support file_offset fetch methods */
 238 #define fetch_file_offset_u8            NULL
 239 #define fetch_file_offset_u16           NULL
 240 #define fetch_file_offset_u32           NULL
 241 #define fetch_file_offset_u64           NULL
 242 #define fetch_file_offset_string        NULL
 243 #define fetch_file_offset_string_size   NULL
 244
 245 /* Fetch type information table */
 246 const struct fetch_type kprobes_fetch_type_table[] = {
 247         /* Special types */
 248         [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
 249                                         sizeof(u32), 1, "__data_loc char[]"),
 250         [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
 251                                         string_size, sizeof(u32), 0, "u32"),
 252         /* Basic types */
 253         ASSIGN_FETCH_TYPE(u8,  u8,  0),
 254         ASSIGN_FETCH_TYPE(u16, u16, 0),
 255         ASSIGN_FETCH_TYPE(u32, u32, 0),
 256         ASSIGN_FETCH_TYPE(u64, u64, 0),
 257         ASSIGN_FETCH_TYPE(s8,  u8,  1),
 258         ASSIGN_FETCH_TYPE(s16, u16, 1),
 259         ASSIGN_FETCH_TYPE(s32, u32, 1),
 260         ASSIGN_FETCH_TYPE(s64, u64, 1),
 261
 262         ASSIGN_FETCH_TYPE_END
 263 };
 264
 265 /*
 266  * Allocate new trace_probe and initialize it (including kprobes).
 267  */
 268 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
 269                                              const char *event,
 270                                              void *addr,
 271                                              const char *symbol,
 272                                              unsigned long offs,
 273                                              int nargs, bool is_return)
 274 {
 275         struct trace_kprobe *tk;
 276         int ret = -ENOMEM;
 277
 278         tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
 279         if (!tk)
 280                 return ERR_PTR(ret);
 281
 282         if (symbol) {
 283                 tk->symbol = kstrdup(symbol, GFP_KERNEL);
 284                 if (!tk->symbol)
 285                         goto error;
 286                 tk->rp.kp.symbol_name = tk->symbol;
 287                 tk->rp.kp.offset = offs;
 288         } else
 289                 tk->rp.kp.addr = addr;
 290
 291         if (is_return)
 292                 tk->rp.handler = kretprobe_dispatcher;
 293         else
 294                 tk->rp.kp.pre_handler = kprobe_dispatcher;
 295
 296         if (!event || !is_good_name(event)) {
 297                 ret = -EINVAL;
 298                 goto error;
 299         }
 300
 301         tk->tp.call.class = &tk->tp.class;
 302         tk->tp.call.name = kstrdup(event, GFP_KERNEL);
 303         if (!tk->tp.call.name)
 304                 goto error;
 305
 306         if (!group || !is_good_name(group)) {
 307                 ret = -EINVAL;
 308                 goto error;
 309         }
 310
 311         tk->tp.class.system = kstrdup(group, GFP_KERNEL);
 312         if (!tk->tp.class.system)
 313                 goto error;
 314
 315         INIT_LIST_HEAD(&tk->list);
 316         INIT_LIST_HEAD(&tk->tp.files);
 317         return tk;
 318 error:
 319         kfree(tk->tp.call.name);
 320         kfree(tk->symbol);
 321         kfree(tk);
 322         return ERR_PTR(ret);
 323 }
 324
 325 static void free_trace_kprobe(struct trace_kprobe *tk)
 326 {
 327         int i;
 328
 329         for (i = 0; i < tk->tp.nr_args; i++)
 330                 traceprobe_free_probe_arg(&tk->tp.args[i]);
 331
 332         kfree(tk->tp.call.class->system);
 333         kfree(tk->tp.call.name);
 334         kfree(tk->symbol);
 335         kfree(tk);
 336 }
 337
 338 static struct trace_kprobe *find_trace_kprobe(const char *event,
 339                                               const char *group)
 340 {
 341         struct trace_kprobe *tk;
 342
 343         list_for_each_entry(tk, &probe_list, list)
 344                 if (strcmp(tk->tp.call.name, event) == 0 &&
 345                     strcmp(tk->tp.call.class->system, group) == 0)
 346                         return tk;
 347         return NULL;
 348 }
 349
 350 /*
 351  * Enable trace_probe
 352  * if the file is NULL, enable "perf" handler, or enable "trace" handler.
 353  */
 354 static int
 355 enable_trace_kprobe(struct trace_kprobe *tk, struct ftrace_event_file *file)
 356 {
 357         int ret = 0;
 358
 359         if (file) {
 360                 struct event_file_link *link;
 361
 362                 link = kmalloc(sizeof(*link), GFP_KERNEL);
 363                 if (!link) {
 364                         ret = -ENOMEM;
 365                         goto out;
 366                 }
 367
 368                 link->file = file;
 369                 list_add_tail_rcu(&link->list, &tk->tp.files);
 370
 371                 tk->tp.flags |= TP_FLAG_TRACE;
 372         } else
 373                 tk->tp.flags |= TP_FLAG_PROFILE;
 374
 375         if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
 376                 if (trace_kprobe_is_return(tk))
 377                         ret = enable_kretprobe(&tk->rp);
 378                 else
 379                         ret = enable_kprobe(&tk->rp.kp);
 380         }
 381  out:
 382         return ret;
 383 }
 384
 385 /*
 386  * Disable trace_probe
 387  * if the file is NULL, disable "perf" handler, or disable "trace" handler.
 388  */
 389 static int
 390 disable_trace_kprobe(struct trace_kprobe *tk, struct ftrace_event_file *file)
 391 {
 392         struct event_file_link *link = NULL;
 393         int wait = 0;
 394         int ret = 0;
 395
 396         if (file) {
 397                 link = find_event_file_link(&tk->tp, file);
 398                 if (!link) {
 399                         ret = -EINVAL;
 400                         goto out;
 401                 }
 402
 403                 list_del_rcu(&link->list);
 404                 wait = 1;
 405                 if (!list_empty(&tk->tp.files))
 406                         goto out;
 407
 408                 tk->tp.flags &= ~TP_FLAG_TRACE;
 409         } else
 410                 tk->tp.flags &= ~TP_FLAG_PROFILE;
 411
 412         if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
 413                 if (trace_kprobe_is_return(tk))
 414                         disable_kretprobe(&tk->rp);
 415                 else
 416                         disable_kprobe(&tk->rp.kp);
 417                 wait = 1;
 418         }
 419  out:
 420         if (wait) {
 421                 /*
 422                  * Synchronize with kprobe_trace_func/kretprobe_trace_func
 423                  * to ensure disabled (all running handlers are finished).
 424                  * This is not only for kfree(), but also the caller,
 425                  * trace_remove_event_call() supposes it for releasing
 426                  * event_call related objects, which will be accessed in
 427                  * the kprobe_trace_func/kretprobe_trace_func.
 428                  */
 429                 synchronize_sched();
 430                 kfree(link);    /* Ignored if link == NULL */
 431         }
 432
 433         return ret;
 434 }
 435
 436 /* Internal register function - just handle k*probes and flags */
 437 static int __register_trace_kprobe(struct trace_kprobe *tk)
 438 {
 439         int i, ret;
 440
 441         if (trace_probe_is_registered(&tk->tp))
 442                 return -EINVAL;
 443
 444         for (i = 0; i < tk->tp.nr_args; i++)
 445                 traceprobe_update_arg(&tk->tp.args[i]);
 446
 447         /* Set/clear disabled flag according to tp->flag */
 448         if (trace_probe_is_enabled(&tk->tp))
 449                 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
 450         else
 451                 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 452
 453         if (trace_kprobe_is_return(tk))
 454                 ret = register_kretprobe(&tk->rp);
 455         else
 456                 ret = register_kprobe(&tk->rp.kp);
 457
 458         if (ret == 0)
 459                 tk->tp.flags |= TP_FLAG_REGISTERED;
 460         else {
 461                 pr_warning("Could not insert probe at %s+%lu: %d\n",
 462                            trace_kprobe_symbol(tk), trace_kprobe_offset(tk), ret);
 463                 if (ret == -ENOENT && trace_kprobe_is_on_module(tk)) {
 464                         pr_warning("This probe might be able to register after"
 465                                    "target module is loaded. Continue.\n");
 466                         ret = 0;
 467                 } else if (ret == -EILSEQ) {
 468                         pr_warning("Probing address(0x%p) is not an "
 469                                    "instruction boundary.\n",
 470                                    tk->rp.kp.addr);
 471                         ret = -EINVAL;
 472                 }
 473         }
 474
 475         return ret;
 476 }
 477
 478 /* Internal unregister function - just handle k*probes and flags */
 479 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
 480 {
 481         if (trace_probe_is_registered(&tk->tp)) {
 482                 if (trace_kprobe_is_return(tk))
 483                         unregister_kretprobe(&tk->rp);
 484                 else
 485                         unregister_kprobe(&tk->rp.kp);
 486                 tk->tp.flags &= ~TP_FLAG_REGISTERED;
 487                 /* Cleanup kprobe for reuse */
 488                 if (tk->rp.kp.symbol_name)
 489                         tk->rp.kp.addr = NULL;
 490         }
 491 }
 492
 493 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
 494 static int unregister_trace_kprobe(struct trace_kprobe *tk)
 495 {
 496         /* Enabled event can not be unregistered */
 497         if (trace_probe_is_enabled(&tk->tp))
 498                 return -EBUSY;
 499
 500         /* Will fail if probe is being used by ftrace or perf */
 501         if (unregister_kprobe_event(tk))
 502                 return -EBUSY;
 503
 504         __unregister_trace_kprobe(tk);
 505         list_del(&tk->list);
 506
 507         return 0;
 508 }
 509
 510 /* Register a trace_probe and probe_event */
 511 static int register_trace_kprobe(struct trace_kprobe *tk)
 512 {
 513         struct trace_kprobe *old_tk;
 514         int ret;
 515
 516         mutex_lock(&probe_lock);
 517
 518         /* Delete old (same name) event if exist */
 519         old_tk = find_trace_kprobe(tk->tp.call.name, tk->tp.call.class->system);
 520         if (old_tk) {
 521                 ret = unregister_trace_kprobe(old_tk);
 522                 if (ret < 0)
 523                         goto end;
 524                 free_trace_kprobe(old_tk);
 525         }
 526
 527         /* Register new event */
 528         ret = register_kprobe_event(tk);
 529         if (ret) {
 530                 pr_warning("Failed to register probe event(%d)\n", ret);
 531                 goto end;
 532         }
 533
 534         /* Register k*probe */
 535         ret = __register_trace_kprobe(tk);
 536         if (ret < 0)
 537                 unregister_kprobe_event(tk);
 538         else
 539                 list_add_tail(&tk->list, &probe_list);
 540
 541 end:
 542         mutex_unlock(&probe_lock);
 543         return ret;
 544 }
 545
 546 /* Module notifier call back, checking event on the module */
 547 static int trace_kprobe_module_callback(struct notifier_block *nb,
 548                                        unsigned long val, void *data)
 549 {
 550         struct module *mod = data;
 551         struct trace_kprobe *tk;
 552         int ret;
 553
 554         if (val != MODULE_STATE_COMING)
 555                 return NOTIFY_DONE;
 556
 557         /* Update probes on coming module */
 558         mutex_lock(&probe_lock);
 559         list_for_each_entry(tk, &probe_list, list) {
 560                 if (trace_kprobe_within_module(tk, mod)) {
 561                         /* Don't need to check busy - this should have gone. */
 562                         __unregister_trace_kprobe(tk);
 563                         ret = __register_trace_kprobe(tk);
 564                         if (ret)
 565                                 pr_warning("Failed to re-register probe %s on"
 566                                            "%s: %d\n",
 567                                            tk->tp.call.name, mod->name, ret);
 568                 }
 569         }
 570         mutex_unlock(&probe_lock);
 571
 572         return NOTIFY_DONE;
 573 }
 574
 575 static struct notifier_block trace_kprobe_module_nb = {
 576         .notifier_call = trace_kprobe_module_callback,
 577         .priority = 1   /* Invoked after kprobe module callback */
 578 };
 579
 580 static int create_trace_kprobe(int argc, char **argv)
 581 {
 582         /*
 583          * Argument syntax:
 584          *  - Add kprobe: p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
 585          *  - Add kretprobe: r[:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
 586          * Fetch args:
 587          *  $retval     : fetch return value
 588          *  $stack      : fetch stack address
 589          *  $stackN     : fetch Nth of stack (N:0-)
 590          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 591          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 592          *  %REG        : fetch register REG
 593          * Dereferencing memory fetch:
 594          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 595          * Alias name of args:
 596          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 597          * Type of args:
 598          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 599          */
 600         struct trace_kprobe *tk;
 601         int i, ret = 0;
 602         bool is_return = false, is_delete = false;
 603         char *symbol = NULL, *event = NULL, *group = NULL;
 604         char *arg;
 605         unsigned long offset = 0;
 606         void *addr = NULL;
 607         char buf[MAX_EVENT_NAME_LEN];
 608
 609         /* argc must be >= 1 */
 610         if (argv[0][0] == 'p')
 611                 is_return = false;
 612         else if (argv[0][0] == 'r')
 613                 is_return = true;
 614         else if (argv[0][0] == '-')
 615                 is_delete = true;
 616         else {
 617                 pr_info("Probe definition must be started with 'p', 'r' or"
 618                         " '-'.\n");
 619                 return -EINVAL;
 620         }
 621
 622         if (argv[0][1] == ':') {
 623                 event = &argv[0][2];
 624                 if (strchr(event, '/')) {
 625                         group = event;
 626                         event = strchr(group, '/') + 1;
 627                         event[-1] = '\0';
 628                         if (strlen(group) == 0) {
 629                                 pr_info("Group name is not specified\n");
 630                                 return -EINVAL;
 631                         }
 632                 }
 633                 if (strlen(event) == 0) {
 634                         pr_info("Event name is not specified\n");
 635                         return -EINVAL;
 636                 }
 637         }
 638         if (!group)
 639                 group = KPROBE_EVENT_SYSTEM;
 640
 641         if (is_delete) {
 642                 if (!event) {
 643                         pr_info("Delete command needs an event name.\n");
 644                         return -EINVAL;
 645                 }
 646                 mutex_lock(&probe_lock);
 647                 tk = find_trace_kprobe(event, group);
 648                 if (!tk) {
 649                         mutex_unlock(&probe_lock);
 650                         pr_info("Event %s/%s doesn't exist.\n", group, event);
 651                         return -ENOENT;
 652                 }
 653                 /* delete an event */
 654                 ret = unregister_trace_kprobe(tk);
 655                 if (ret == 0)
 656                         free_trace_kprobe(tk);
 657                 mutex_unlock(&probe_lock);
 658                 return ret;
 659         }
 660
 661         if (argc < 2) {
 662                 pr_info("Probe point is not specified.\n");
 663                 return -EINVAL;
 664         }
 665         if (isdigit(argv[1][0])) {
 666                 if (is_return) {
 667                         pr_info("Return probe point must be a symbol.\n");
 668                         return -EINVAL;
 669                 }
 670                 /* an address specified */
 671                 ret = kstrtoul(&argv[1][0], 0, (unsigned long *)&addr);
 672                 if (ret) {
 673                         pr_info("Failed to parse address.\n");
 674                         return ret;
 675                 }
 676         } else {
 677                 /* a symbol specified */
 678                 symbol = argv[1];
 679                 /* TODO: support .init module functions */
 680                 ret = traceprobe_split_symbol_offset(symbol, &offset);
 681                 if (ret) {
 682                         pr_info("Failed to parse symbol.\n");
 683                         return ret;
 684                 }
 685                 if (offset && is_return) {
 686                         pr_info("Return probe must be used without offset.\n");
 687                         return -EINVAL;
 688                 }
 689         }
 690         argc -= 2; argv += 2;
 691
 692         /* setup a probe */
 693         if (!event) {
 694                 /* Make a new event name */
 695                 if (symbol)
 696                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 697                                  is_return ? 'r' : 'p', symbol, offset);
 698                 else
 699                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 700                                  is_return ? 'r' : 'p', addr);
 701                 event = buf;
 702         }
 703         tk = alloc_trace_kprobe(group, event, addr, symbol, offset, argc,
 704                                is_return);
 705         if (IS_ERR(tk)) {
 706                 pr_info("Failed to allocate trace_probe.(%d)\n",
 707                         (int)PTR_ERR(tk));
 708                 return PTR_ERR(tk);
 709         }
 710
 711         /* parse arguments */
 712         ret = 0;
 713         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 714                 struct probe_arg *parg = &tk->tp.args[i];
 715
 716                 /* Increment count for freeing args in error case */
 717                 tk->tp.nr_args++;
 718
 719                 /* Parse argument name */
 720                 arg = strchr(argv[i], '=');
 721                 if (arg) {
 722                         *arg++ = '\0';
 723                         parg->name = kstrdup(argv[i], GFP_KERNEL);
 724                 } else {
 725                         arg = argv[i];
 726                         /* If argument name is omitted, set "argN" */
 727                         snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
 728                         parg->name = kstrdup(buf, GFP_KERNEL);
 729                 }
 730
 731                 if (!parg->name) {
 732                         pr_info("Failed to allocate argument[%d] name.\n", i);
 733                         ret = -ENOMEM;
 734                         goto error;
 735                 }
 736
 737                 if (!is_good_name(parg->name)) {
 738                         pr_info("Invalid argument[%d] name: %s\n",
 739                                 i, parg->name);
 740                         ret = -EINVAL;
 741                         goto error;
 742                 }
 743
 744                 if (traceprobe_conflict_field_name(parg->name,
 745                                                         tk->tp.args, i)) {
 746                         pr_info("Argument[%d] name '%s' conflicts with "
 747                                 "another field.\n", i, argv[i]);
 748                         ret = -EINVAL;
 749                         goto error;
 750                 }
 751
 752                 /* Parse fetch argument */
 753                 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
 754                                                 is_return, true);
 755                 if (ret) {
 756                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
 757                         goto error;
 758                 }
 759         }
 760
 761         ret = register_trace_kprobe(tk);
 762         if (ret)
 763                 goto error;
 764         return 0;
 765
 766 error:
 767         free_trace_kprobe(tk);
 768         return ret;
 769 }
 770
 771 static int release_all_trace_kprobes(void)
 772 {
 773         struct trace_kprobe *tk;
 774         int ret = 0;
 775
 776         mutex_lock(&probe_lock);
 777         /* Ensure no probe is in use. */
 778         list_for_each_entry(tk, &probe_list, list)
 779                 if (trace_probe_is_enabled(&tk->tp)) {
 780                         ret = -EBUSY;
 781                         goto end;
 782                 }
 783         /* TODO: Use batch unregistration */
 784         while (!list_empty(&probe_list)) {
 785                 tk = list_entry(probe_list.next, struct trace_kprobe, list);
 786                 ret = unregister_trace_kprobe(tk);
 787                 if (ret)
 788                         goto end;
 789                 free_trace_kprobe(tk);
 790         }
 791
 792 end:
 793         mutex_unlock(&probe_lock);
 794
 795         return ret;
 796 }
 797
 798 /* Probes listing interfaces */
 799 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
 800 {
 801         mutex_lock(&probe_lock);
 802         return seq_list_start(&probe_list, *pos);
 803 }
 804
 805 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
 806 {
 807         return seq_list_next(v, &probe_list, pos);
 808 }
 809
 810 static void probes_seq_stop(struct seq_file *m, void *v)
 811 {
 812         mutex_unlock(&probe_lock);
 813 }
 814
 815 static int probes_seq_show(struct seq_file *m, void *v)
 816 {
 817         struct trace_kprobe *tk = v;
 818         int i;
 819
 820         seq_printf(m, "%c", trace_kprobe_is_return(tk) ? 'r' : 'p');
 821         seq_printf(m, ":%s/%s", tk->tp.call.class->system, tk->tp.call.name);
 822
 823         if (!tk->symbol)
 824                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
 825         else if (tk->rp.kp.offset)
 826                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
 827                            tk->rp.kp.offset);
 828         else
 829                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
 830
 831         for (i = 0; i < tk->tp.nr_args; i++)
 832                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
 833         seq_printf(m, "\n");
 834
 835         return 0;
 836 }
 837
 838 static const struct seq_operations probes_seq_op = {
 839         .start  = probes_seq_start,
 840         .next   = probes_seq_next,
 841         .stop   = probes_seq_stop,
 842         .show   = probes_seq_show
 843 };
 844
 845 static int probes_open(struct inode *inode, struct file *file)
 846 {
 847         int ret;
 848
 849         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
 850                 ret = release_all_trace_kprobes();
 851                 if (ret < 0)
 852                         return ret;
 853         }
 854
 855         return seq_open(file, &probes_seq_op);
 856 }
 857
 858 static ssize_t probes_write(struct file *file, const char __user *buffer,
 859                             size_t count, loff_t *ppos)
 860 {
 861         return traceprobe_probes_write(file, buffer, count, ppos,
 862                         create_trace_kprobe);
 863 }
 864
 865 static const struct file_operations kprobe_events_ops = {
 866         .owner          = THIS_MODULE,
 867         .open           = probes_open,
 868         .read           = seq_read,
 869         .llseek         = seq_lseek,
 870         .release        = seq_release,
 871         .write          = probes_write,
 872 };
 873
 874 /* Probes profiling interfaces */
 875 static int probes_profile_seq_show(struct seq_file *m, void *v)
 876 {
 877         struct trace_kprobe *tk = v;
 878
 879         seq_printf(m, "  %-44s %15lu %15lu\n", tk->tp.call.name, tk->nhit,
 880                    tk->rp.kp.nmissed);
 881
 882         return 0;
 883 }
 884
 885 static const struct seq_operations profile_seq_op = {
 886         .start  = probes_seq_start,
 887         .next   = probes_seq_next,
 888         .stop   = probes_seq_stop,
 889         .show   = probes_profile_seq_show
 890 };
 891
 892 static int profile_open(struct inode *inode, struct file *file)
 893 {
 894         return seq_open(file, &profile_seq_op);
 895 }
 896
 897 static const struct file_operations kprobe_profile_ops = {
 898         .owner          = THIS_MODULE,
 899         .open           = profile_open,
 900         .read           = seq_read,
 901         .llseek         = seq_lseek,
 902         .release        = seq_release,
 903 };
 904
 905 /* Kprobe handler */
 906 static __kprobes void
 907 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
 908                     struct ftrace_event_file *ftrace_file)
 909 {
 910         struct kprobe_trace_entry_head *entry;
 911         struct ring_buffer_event *event;
 912         struct ring_buffer *buffer;
 913         int size, dsize, pc;
 914         unsigned long irq_flags;
 915         struct ftrace_event_call *call = &tk->tp.call;
 916
 917         WARN_ON(call != ftrace_file->event_call);
 918
 919         if (ftrace_trigger_soft_disabled(ftrace_file))
 920                 return;
 921
 922         local_save_flags(irq_flags);
 923         pc = preempt_count();
 924
 925         dsize = __get_data_size(&tk->tp, regs);
 926         size = sizeof(*entry) + tk->tp.size + dsize;
 927
 928         event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,
 929                                                 call->event.type,
 930                                                 size, irq_flags, pc);
 931         if (!event)
 932                 return;
 933
 934         entry = ring_buffer_event_data(event);
 935         entry->ip = (unsigned long)tk->rp.kp.addr;
 936         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
 937
 938         event_trigger_unlock_commit_regs(ftrace_file, buffer, event,
 939                                          entry, irq_flags, pc, regs);
 940 }
 941
 942 static __kprobes void
 943 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
 944 {
 945         struct event_file_link *link;
 946
 947         list_for_each_entry_rcu(link, &tk->tp.files, list)
 948                 __kprobe_trace_func(tk, regs, link->file);
 949 }
 950
 951 /* Kretprobe handler */
 952 static __kprobes void
 953 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
 954                        struct pt_regs *regs,
 955                        struct ftrace_event_file *ftrace_file)
 956 {
 957         struct kretprobe_trace_entry_head *entry;
 958         struct ring_buffer_event *event;
 959         struct ring_buffer *buffer;
 960         int size, pc, dsize;
 961         unsigned long irq_flags;
 962         struct ftrace_event_call *call = &tk->tp.call;
 963
 964         WARN_ON(call != ftrace_file->event_call);
 965
 966         if (ftrace_trigger_soft_disabled(ftrace_file))
 967                 return;
 968
 969         local_save_flags(irq_flags);
 970         pc = preempt_count();
 971
 972         dsize = __get_data_size(&tk->tp, regs);
 973         size = sizeof(*entry) + tk->tp.size + dsize;
 974
 975         event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,
 976                                                 call->event.type,
 977                                                 size, irq_flags, pc);
 978         if (!event)
 979                 return;
 980
 981         entry = ring_buffer_event_data(event);
 982         entry->func = (unsigned long)tk->rp.kp.addr;
 983         entry->ret_ip = (unsigned long)ri->ret_addr;
 984         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
 985
 986         event_trigger_unlock_commit_regs(ftrace_file, buffer, event,
 987                                          entry, irq_flags, pc, regs);
 988 }
 989
 990 static __kprobes void
 991 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
 992                      struct pt_regs *regs)
 993 {
 994         struct event_file_link *link;
 995
 996         list_for_each_entry_rcu(link, &tk->tp.files, list)
 997                 __kretprobe_trace_func(tk, ri, regs, link->file);
 998 }
 999
1000 /* Event entry printers */
1001 static enum print_line_t
1002 print_kprobe_event(struct trace_iterator *iter, int flags,
1003                    struct trace_event *event)
1004 {
1005         struct kprobe_trace_entry_head *field;
1006         struct trace_seq *s = &iter->seq;
1007         struct trace_probe *tp;
1008         u8 *data;
1009         int i;
1010
1011         field = (struct kprobe_trace_entry_head *)iter->ent;
1012         tp = container_of(event, struct trace_probe, call.event);
1013
1014         if (!trace_seq_printf(s, "%s: (", tp->call.name))
1015                 goto partial;
1016
1017         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1018                 goto partial;
1019
1020         if (!trace_seq_puts(s, ")"))
1021                 goto partial;
1022
1023         data = (u8 *)&field[1];
1024         for (i = 0; i < tp->nr_args; i++)
1025                 if (!tp->args[i].type->print(s, tp->args[i].name,
1026                                              data + tp->args[i].offset, field))
1027                         goto partial;
1028
1029         if (!trace_seq_puts(s, "\n"))
1030                 goto partial;
1031
1032         return TRACE_TYPE_HANDLED;
1033 partial:
1034         return TRACE_TYPE_PARTIAL_LINE;
1035 }
1036
1037 static enum print_line_t
1038 print_kretprobe_event(struct trace_iterator *iter, int flags,
1039                       struct trace_event *event)
1040 {
1041         struct kretprobe_trace_entry_head *field;
1042         struct trace_seq *s = &iter->seq;
1043         struct trace_probe *tp;
1044         u8 *data;
1045         int i;
1046
1047         field = (struct kretprobe_trace_entry_head *)iter->ent;
1048         tp = container_of(event, struct trace_probe, call.event);
1049
1050         if (!trace_seq_printf(s, "%s: (", tp->call.name))
1051                 goto partial;
1052
1053         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1054                 goto partial;
1055
1056         if (!trace_seq_puts(s, " <- "))
1057                 goto partial;
1058
1059         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1060                 goto partial;
1061
1062         if (!trace_seq_puts(s, ")"))
1063                 goto partial;
1064
1065         data = (u8 *)&field[1];
1066         for (i = 0; i < tp->nr_args; i++)
1067                 if (!tp->args[i].type->print(s, tp->args[i].name,
1068                                              data + tp->args[i].offset, field))
1069                         goto partial;
1070
1071         if (!trace_seq_puts(s, "\n"))
1072                 goto partial;
1073
1074         return TRACE_TYPE_HANDLED;
1075 partial:
1076         return TRACE_TYPE_PARTIAL_LINE;
1077 }
1078
1079
1080 static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1081 {
1082         int ret, i;
1083         struct kprobe_trace_entry_head field;
1084         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1085
1086         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1087         /* Set argument names as fields */
1088         for (i = 0; i < tk->tp.nr_args; i++) {
1089                 struct probe_arg *parg = &tk->tp.args[i];
1090
1091                 ret = trace_define_field(event_call, parg->type->fmttype,
1092                                          parg->name,
1093                                          sizeof(field) + parg->offset,
1094                                          parg->type->size,
1095                                          parg->type->is_signed,
1096                                          FILTER_OTHER);
1097                 if (ret)
1098                         return ret;
1099         }
1100         return 0;
1101 }
1102
1103 static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1104 {
1105         int ret, i;
1106         struct kretprobe_trace_entry_head field;
1107         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1108
1109         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1110         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1111         /* Set argument names as fields */
1112         for (i = 0; i < tk->tp.nr_args; i++) {
1113                 struct probe_arg *parg = &tk->tp.args[i];
1114
1115                 ret = trace_define_field(event_call, parg->type->fmttype,
1116                                          parg->name,
1117                                          sizeof(field) + parg->offset,
1118                                          parg->type->size,
1119                                          parg->type->is_signed,
1120                                          FILTER_OTHER);
1121                 if (ret)
1122                         return ret;
1123         }
1124         return 0;
1125 }
1126
1127 #ifdef CONFIG_PERF_EVENTS
1128
1129 /* Kprobe profile handler */
1130 static __kprobes void
1131 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1132 {
1133         struct ftrace_event_call *call = &tk->tp.call;
1134         struct kprobe_trace_entry_head *entry;
1135         struct hlist_head *head;
1136         int size, __size, dsize;
1137         int rctx;
1138
1139         head = this_cpu_ptr(call->perf_events);
1140         if (hlist_empty(head))
1141                 return;
1142
1143         dsize = __get_data_size(&tk->tp, regs);
1144         __size = sizeof(*entry) + tk->tp.size + dsize;
1145         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1146         size -= sizeof(u32);
1147
1148         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1149         if (!entry)
1150                 return;
1151
1152         entry->ip = (unsigned long)tk->rp.kp.addr;
1153         memset(&entry[1], 0, dsize);
1154         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1155         perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1156 }
1157
1158 /* Kretprobe profile handler */
1159 static __kprobes void
1160 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1161                     struct pt_regs *regs)
1162 {
1163         struct ftrace_event_call *call = &tk->tp.call;
1164         struct kretprobe_trace_entry_head *entry;
1165         struct hlist_head *head;
1166         int size, __size, dsize;
1167         int rctx;
1168
1169         head = this_cpu_ptr(call->perf_events);
1170         if (hlist_empty(head))
1171                 return;
1172
1173         dsize = __get_data_size(&tk->tp, regs);
1174         __size = sizeof(*entry) + tk->tp.size + dsize;
1175         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1176         size -= sizeof(u32);
1177
1178         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1179         if (!entry)
1180                 return;
1181
1182         entry->func = (unsigned long)tk->rp.kp.addr;
1183         entry->ret_ip = (unsigned long)ri->ret_addr;
1184         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1185         perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1186 }
1187 #endif  /* CONFIG_PERF_EVENTS */
1188
1189 /*
1190  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1191  *
1192  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1193  * lockless, but we can't race with this __init function.
1194  */
1195 static __kprobes
1196 int kprobe_register(struct ftrace_event_call *event,
1197                     enum trace_reg type, void *data)
1198 {
1199         struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1200         struct ftrace_event_file *file = data;
1201
1202         switch (type) {
1203         case TRACE_REG_REGISTER:
1204                 return enable_trace_kprobe(tk, file);
1205         case TRACE_REG_UNREGISTER:
1206                 return disable_trace_kprobe(tk, file);
1207
1208 #ifdef CONFIG_PERF_EVENTS
1209         case TRACE_REG_PERF_REGISTER:
1210                 return enable_trace_kprobe(tk, NULL);
1211         case TRACE_REG_PERF_UNREGISTER:
1212                 return disable_trace_kprobe(tk, NULL);
1213         case TRACE_REG_PERF_OPEN:
1214         case TRACE_REG_PERF_CLOSE:
1215         case TRACE_REG_PERF_ADD:
1216         case TRACE_REG_PERF_DEL:
1217                 return 0;
1218 #endif
1219         }
1220         return 0;
1221 }
1222
1223 static __kprobes
1224 int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1225 {
1226         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1227
1228         tk->nhit++;
1229
1230         if (tk->tp.flags & TP_FLAG_TRACE)
1231                 kprobe_trace_func(tk, regs);
1232 #ifdef CONFIG_PERF_EVENTS
1233         if (tk->tp.flags & TP_FLAG_PROFILE)
1234                 kprobe_perf_func(tk, regs);
1235 #endif
1236         return 0;       /* We don't tweek kernel, so just return 0 */
1237 }
1238
1239 static __kprobes
1240 int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1241 {
1242         struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1243
1244         tk->nhit++;
1245
1246         if (tk->tp.flags & TP_FLAG_TRACE)
1247                 kretprobe_trace_func(tk, ri, regs);
1248 #ifdef CONFIG_PERF_EVENTS
1249         if (tk->tp.flags & TP_FLAG_PROFILE)
1250                 kretprobe_perf_func(tk, ri, regs);
1251 #endif
1252         return 0;       /* We don't tweek kernel, so just return 0 */
1253 }
1254
1255 static struct trace_event_functions kretprobe_funcs = {
1256         .trace          = print_kretprobe_event
1257 };
1258
1259 static struct trace_event_functions kprobe_funcs = {
1260         .trace          = print_kprobe_event
1261 };
1262
1263 static int register_kprobe_event(struct trace_kprobe *tk)
1264 {
1265         struct ftrace_event_call *call = &tk->tp.call;
1266         int ret;
1267
1268         /* Initialize ftrace_event_call */
1269         INIT_LIST_HEAD(&call->class->fields);
1270         if (trace_kprobe_is_return(tk)) {
1271                 call->event.funcs = &kretprobe_funcs;
1272                 call->class->define_fields = kretprobe_event_define_fields;
1273         } else {
1274                 call->event.funcs = &kprobe_funcs;
1275                 call->class->define_fields = kprobe_event_define_fields;
1276         }
1277         if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1278                 return -ENOMEM;
1279         ret = register_ftrace_event(&call->event);
1280         if (!ret) {
1281                 kfree(call->print_fmt);
1282                 return -ENODEV;
1283         }
1284         call->flags = 0;
1285         call->class->reg = kprobe_register;
1286         call->data = tk;
1287         ret = trace_add_event_call(call);
1288         if (ret) {
1289                 pr_info("Failed to register kprobe event: %s\n", call->name);
1290                 kfree(call->print_fmt);
1291                 unregister_ftrace_event(&call->event);
1292         }
1293         return ret;
1294 }
1295
1296 static int unregister_kprobe_event(struct trace_kprobe *tk)
1297 {
1298         int ret;
1299
1300         /* tp->event is unregistered in trace_remove_event_call() */
1301         ret = trace_remove_event_call(&tk->tp.call);
1302         if (!ret)
1303                 kfree(tk->tp.call.print_fmt);
1304         return ret;
1305 }
1306
1307 /* Make a debugfs interface for controlling probe points */
1308 static __init int init_kprobe_trace(void)
1309 {
1310         struct dentry *d_tracer;
1311         struct dentry *entry;
1312
1313         if (register_module_notifier(&trace_kprobe_module_nb))
1314                 return -EINVAL;
1315
1316         d_tracer = tracing_init_dentry();
1317         if (!d_tracer)
1318                 return 0;
1319
1320         entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
1321                                     NULL, &kprobe_events_ops);
1322
1323         /* Event list interface */
1324         if (!entry)
1325                 pr_warning("Could not create debugfs "
1326                            "'kprobe_events' entry\n");
1327
1328         /* Profile interface */
1329         entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
1330                                     NULL, &kprobe_profile_ops);
1331
1332         if (!entry)
1333                 pr_warning("Could not create debugfs "
1334                            "'kprobe_profile' entry\n");
1335         return 0;
1336 }
1337 fs_initcall(init_kprobe_trace);
1338
1339
1340 #ifdef CONFIG_FTRACE_STARTUP_TEST
1341
1342 /*
1343  * The "__used" keeps gcc from removing the function symbol
1344  * from the kallsyms table.
1345  */
1346 static __used int kprobe_trace_selftest_target(int a1, int a2, int a3,
1347                                                int a4, int a5, int a6)
1348 {
1349         return a1 + a2 + a3 + a4 + a5 + a6;
1350 }
1351
1352 static struct ftrace_event_file *
1353 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1354 {
1355         struct ftrace_event_file *file;
1356
1357         list_for_each_entry(file, &tr->events, list)
1358                 if (file->event_call == &tk->tp.call)
1359                         return file;
1360
1361         return NULL;
1362 }
1363
1364 /*
1365  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1366  * stage, we can do this lockless.
1367  */
1368 static __init int kprobe_trace_self_tests_init(void)
1369 {
1370         int ret, warn = 0;
1371         int (*target)(int, int, int, int, int, int);
1372         struct trace_kprobe *tk;
1373         struct ftrace_event_file *file;
1374
1375         target = kprobe_trace_selftest_target;
1376
1377         pr_info("Testing kprobe tracing: ");
1378
1379         ret = traceprobe_command("p:testprobe kprobe_trace_selftest_target "
1380                                   "$stack $stack0 +0($stack)",
1381                                   create_trace_kprobe);
1382         if (WARN_ON_ONCE(ret)) {
1383                 pr_warn("error on probing function entry.\n");
1384                 warn++;
1385         } else {
1386                 /* Enable trace point */
1387                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1388                 if (WARN_ON_ONCE(tk == NULL)) {
1389                         pr_warn("error on getting new probe.\n");
1390                         warn++;
1391                 } else {
1392                         file = find_trace_probe_file(tk, top_trace_array());
1393                         if (WARN_ON_ONCE(file == NULL)) {
1394                                 pr_warn("error on getting probe file.\n");
1395                                 warn++;
1396                         } else
1397                                 enable_trace_kprobe(tk, file);
1398                 }
1399         }
1400
1401         ret = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target "
1402                                   "$retval", create_trace_kprobe);
1403         if (WARN_ON_ONCE(ret)) {
1404                 pr_warn("error on probing function return.\n");
1405                 warn++;
1406         } else {
1407                 /* Enable trace point */
1408                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1409                 if (WARN_ON_ONCE(tk == NULL)) {
1410                         pr_warn("error on getting 2nd new probe.\n");
1411                         warn++;
1412                 } else {
1413                         file = find_trace_probe_file(tk, top_trace_array());
1414                         if (WARN_ON_ONCE(file == NULL)) {
1415                                 pr_warn("error on getting probe file.\n");
1416                                 warn++;
1417                         } else
1418                                 enable_trace_kprobe(tk, file);
1419                 }
1420         }
1421
1422         if (warn)
1423                 goto end;
1424
1425         ret = target(1, 2, 3, 4, 5, 6);
1426
1427         /* Disable trace points before removing it */
1428         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1429         if (WARN_ON_ONCE(tk == NULL)) {
1430                 pr_warn("error on getting test probe.\n");
1431                 warn++;
1432         } else {
1433                 file = find_trace_probe_file(tk, top_trace_array());
1434                 if (WARN_ON_ONCE(file == NULL)) {
1435                         pr_warn("error on getting probe file.\n");
1436                         warn++;
1437                 } else
1438                         disable_trace_kprobe(tk, file);
1439         }
1440
1441         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1442         if (WARN_ON_ONCE(tk == NULL)) {
1443                 pr_warn("error on getting 2nd test probe.\n");
1444                 warn++;
1445         } else {
1446                 file = find_trace_probe_file(tk, top_trace_array());
1447                 if (WARN_ON_ONCE(file == NULL)) {
1448                         pr_warn("error on getting probe file.\n");
1449                         warn++;
1450                 } else
1451                         disable_trace_kprobe(tk, file);
1452         }
1453
1454         ret = traceprobe_command("-:testprobe", create_trace_kprobe);
1455         if (WARN_ON_ONCE(ret)) {
1456                 pr_warn("error on deleting a probe.\n");
1457                 warn++;
1458         }
1459
1460         ret = traceprobe_command("-:testprobe2", create_trace_kprobe);
1461         if (WARN_ON_ONCE(ret)) {
1462                 pr_warn("error on deleting a probe.\n");
1463                 warn++;
1464         }
1465
1466 end:
1467         release_all_trace_kprobes();
1468         if (warn)
1469                 pr_cont("NG: Some tests are failed. Please check them.\n");
1470         else
1471                 pr_cont("OK\n");
1472         return 0;
1473 }
1474
1475 late_initcall(kprobe_trace_self_tests_init);
1476
1477 #endif