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 #define pr_fmt(fmt)     "trace_kprobe: " fmt
  20
  21 #include <linux/module.h>
  22 #include <linux/uaccess.h>
  23
  24 #include "trace_probe.h"
  25
  26 #define KPROBE_EVENT_SYSTEM "kprobes"
  27
  28 /**
  29  * Kprobe event core functions
  30  */
  31 struct trace_kprobe {
  32         struct list_head        list;
  33         struct kretprobe        rp;     /* Use rp.kp for kprobe use */
  34         unsigned long __percpu *nhit;
  35         const char              *symbol;        /* symbol name */
  36         struct trace_probe      tp;
  37 };
  38
  39 #define SIZEOF_TRACE_KPROBE(n)                          \
  40         (offsetof(struct trace_kprobe, tp.args) +       \
  41         (sizeof(struct probe_arg) * (n)))
  42
  43
  44 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
  45 {
  46         return tk->rp.handler != NULL;
  47 }
  48
  49 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
  50 {
  51         return tk->symbol ? tk->symbol : "unknown";
  52 }
  53
  54 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
  55 {
  56         return tk->rp.kp.offset;
  57 }
  58
  59 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
  60 {
  61         return !!(kprobe_gone(&tk->rp.kp));
  62 }
  63
  64 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
  65                                                  struct module *mod)
  66 {
  67         int len = strlen(mod->name);
  68         const char *name = trace_kprobe_symbol(tk);
  69         return strncmp(mod->name, name, len) == 0 && name[len] == ':';
  70 }
  71
  72 static nokprobe_inline bool trace_kprobe_is_on_module(struct trace_kprobe *tk)
  73 {
  74         return !!strchr(trace_kprobe_symbol(tk), ':');
  75 }
  76
  77 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
  78 {
  79         unsigned long nhit = 0;
  80         int cpu;
  81
  82         for_each_possible_cpu(cpu)
  83                 nhit += *per_cpu_ptr(tk->nhit, cpu);
  84
  85         return nhit;
  86 }
  87
  88 static int register_kprobe_event(struct trace_kprobe *tk);
  89 static int unregister_kprobe_event(struct trace_kprobe *tk);
  90
  91 static DEFINE_MUTEX(probe_lock);
  92 static LIST_HEAD(probe_list);
  93
  94 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
  95 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
  96                                 struct pt_regs *regs);
  97
  98 /* Memory fetching by symbol */
  99 struct symbol_cache {
 100         char            *symbol;
 101         long            offset;
 102         unsigned long   addr;
 103 };
 104
 105 unsigned long update_symbol_cache(struct symbol_cache *sc)
 106 {
 107         sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
 108
 109         if (sc->addr)
 110                 sc->addr += sc->offset;
 111
 112         return sc->addr;
 113 }
 114
 115 void free_symbol_cache(struct symbol_cache *sc)
 116 {
 117         kfree(sc->symbol);
 118         kfree(sc);
 119 }
 120
 121 struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
 122 {
 123         struct symbol_cache *sc;
 124
 125         if (!sym || strlen(sym) == 0)
 126                 return NULL;
 127
 128         sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
 129         if (!sc)
 130                 return NULL;
 131
 132         sc->symbol = kstrdup(sym, GFP_KERNEL);
 133         if (!sc->symbol) {
 134                 kfree(sc);
 135                 return NULL;
 136         }
 137         sc->offset = offset;
 138         update_symbol_cache(sc);
 139
 140         return sc;
 141 }
 142
 143 /*
 144  * Kprobes-specific fetch functions
 145  */
 146 #define DEFINE_FETCH_stack(type)                                        \
 147 static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,          \
 148                                           void *offset, void *dest)     \
 149 {                                                                       \
 150         *(type *)dest = (type)regs_get_kernel_stack_nth(regs,           \
 151                                 (unsigned int)((unsigned long)offset)); \
 152 }                                                                       \
 153 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(stack, type));
 154
 155 DEFINE_BASIC_FETCH_FUNCS(stack)
 156 /* No string on the stack entry */
 157 #define fetch_stack_string      NULL
 158 #define fetch_stack_string_size NULL
 159
 160 #define DEFINE_FETCH_memory(type)                                       \
 161 static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,         \
 162                                           void *addr, void *dest)       \
 163 {                                                                       \
 164         type retval;                                                    \
 165         if (probe_kernel_address(addr, retval))                         \
 166                 *(type *)dest = 0;                                      \
 167         else                                                            \
 168                 *(type *)dest = retval;                                 \
 169 }                                                                       \
 170 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, type));
 171
 172 DEFINE_BASIC_FETCH_FUNCS(memory)
 173 /*
 174  * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
 175  * length and relative data location.
 176  */
 177 static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
 178                                             void *addr, void *dest)
 179 {
 180         int maxlen = get_rloc_len(*(u32 *)dest);
 181         u8 *dst = get_rloc_data(dest);
 182         long ret;
 183
 184         if (!maxlen)
 185                 return;
 186
 187         /*
 188          * Try to get string again, since the string can be changed while
 189          * probing.
 190          */
 191         ret = strncpy_from_unsafe(dst, addr, maxlen);
 192
 193         if (ret < 0) {  /* Failed to fetch string */
 194                 dst[0] = '\0';
 195                 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
 196         } else {
 197                 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
 198         }
 199 }
 200 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string));
 201
 202 /* Return the length of string -- including null terminal byte */
 203 static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
 204                                                  void *addr, void *dest)
 205 {
 206         mm_segment_t old_fs;
 207         int ret, len = 0;
 208         u8 c;
 209
 210         old_fs = get_fs();
 211         set_fs(KERNEL_DS);
 212         pagefault_disable();
 213
 214         do {
 215                 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
 216                 len++;
 217         } while (c && ret == 0 && len < MAX_STRING_SIZE);
 218
 219         pagefault_enable();
 220         set_fs(old_fs);
 221
 222         if (ret < 0)    /* Failed to check the length */
 223                 *(u32 *)dest = 0;
 224         else
 225                 *(u32 *)dest = len;
 226 }
 227 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string_size));
 228
 229 #define DEFINE_FETCH_symbol(type)                                       \
 230 void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs, void *data, void *dest)\
 231 {                                                                       \
 232         struct symbol_cache *sc = data;                                 \
 233         if (sc->addr)                                                   \
 234                 fetch_memory_##type(regs, (void *)sc->addr, dest);      \
 235         else                                                            \
 236                 *(type *)dest = 0;                                      \
 237 }                                                                       \
 238 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(symbol, type));
 239
 240 DEFINE_BASIC_FETCH_FUNCS(symbol)
 241 DEFINE_FETCH_symbol(string)
 242 DEFINE_FETCH_symbol(string_size)
 243
 244 /* kprobes don't support file_offset fetch methods */
 245 #define fetch_file_offset_u8            NULL
 246 #define fetch_file_offset_u16           NULL
 247 #define fetch_file_offset_u32           NULL
 248 #define fetch_file_offset_u64           NULL
 249 #define fetch_file_offset_string        NULL
 250 #define fetch_file_offset_string_size   NULL
 251
 252 /* Fetch type information table */
 253 static const struct fetch_type kprobes_fetch_type_table[] = {
 254         /* Special types */
 255         [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
 256                                         sizeof(u32), 1, "__data_loc char[]"),
 257         [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
 258                                         string_size, sizeof(u32), 0, "u32"),
 259         /* Basic types */
 260         ASSIGN_FETCH_TYPE(u8,  u8,  0),
 261         ASSIGN_FETCH_TYPE(u16, u16, 0),
 262         ASSIGN_FETCH_TYPE(u32, u32, 0),
 263         ASSIGN_FETCH_TYPE(u64, u64, 0),
 264         ASSIGN_FETCH_TYPE(s8,  u8,  1),
 265         ASSIGN_FETCH_TYPE(s16, u16, 1),
 266         ASSIGN_FETCH_TYPE(s32, u32, 1),
 267         ASSIGN_FETCH_TYPE(s64, u64, 1),
 268         ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),
 269         ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
 270         ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
 271         ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
 272
 273         ASSIGN_FETCH_TYPE_END
 274 };
 275
 276 /*
 277  * Allocate new trace_probe and initialize it (including kprobes).
 278  */
 279 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
 280                                              const char *event,
 281                                              void *addr,
 282                                              const char *symbol,
 283                                              unsigned long offs,
 284                                              int nargs, bool is_return)
 285 {
 286         struct trace_kprobe *tk;
 287         int ret = -ENOMEM;
 288
 289         tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
 290         if (!tk)
 291                 return ERR_PTR(ret);
 292
 293         tk->nhit = alloc_percpu(unsigned long);
 294         if (!tk->nhit)
 295                 goto error;
 296
 297         if (symbol) {
 298                 tk->symbol = kstrdup(symbol, GFP_KERNEL);
 299                 if (!tk->symbol)
 300                         goto error;
 301                 tk->rp.kp.symbol_name = tk->symbol;
 302                 tk->rp.kp.offset = offs;
 303         } else
 304                 tk->rp.kp.addr = addr;
 305
 306         if (is_return)
 307                 tk->rp.handler = kretprobe_dispatcher;
 308         else
 309                 tk->rp.kp.pre_handler = kprobe_dispatcher;
 310
 311         if (!event || !is_good_name(event)) {
 312                 ret = -EINVAL;
 313                 goto error;
 314         }
 315
 316         tk->tp.call.class = &tk->tp.class;
 317         tk->tp.call.name = kstrdup(event, GFP_KERNEL);
 318         if (!tk->tp.call.name)
 319                 goto error;
 320
 321         if (!group || !is_good_name(group)) {
 322                 ret = -EINVAL;
 323                 goto error;
 324         }
 325
 326         tk->tp.class.system = kstrdup(group, GFP_KERNEL);
 327         if (!tk->tp.class.system)
 328                 goto error;
 329
 330         INIT_LIST_HEAD(&tk->list);
 331         INIT_LIST_HEAD(&tk->tp.files);
 332         return tk;
 333 error:
 334         kfree(tk->tp.call.name);
 335         kfree(tk->symbol);
 336         free_percpu(tk->nhit);
 337         kfree(tk);
 338         return ERR_PTR(ret);
 339 }
 340
 341 static void free_trace_kprobe(struct trace_kprobe *tk)
 342 {
 343         int i;
 344
 345         for (i = 0; i < tk->tp.nr_args; i++)
 346                 traceprobe_free_probe_arg(&tk->tp.args[i]);
 347
 348         kfree(tk->tp.call.class->system);
 349         kfree(tk->tp.call.name);
 350         kfree(tk->symbol);
 351         free_percpu(tk->nhit);
 352         kfree(tk);
 353 }
 354
 355 static struct trace_kprobe *find_trace_kprobe(const char *event,
 356                                               const char *group)
 357 {
 358         struct trace_kprobe *tk;
 359
 360         list_for_each_entry(tk, &probe_list, list)
 361                 if (strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
 362                     strcmp(tk->tp.call.class->system, group) == 0)
 363                         return tk;
 364         return NULL;
 365 }
 366
 367 /*
 368  * Enable trace_probe
 369  * if the file is NULL, enable "perf" handler, or enable "trace" handler.
 370  */
 371 static int
 372 enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
 373 {
 374         int ret = 0;
 375
 376         if (file) {
 377                 struct event_file_link *link;
 378
 379                 link = kmalloc(sizeof(*link), GFP_KERNEL);
 380                 if (!link) {
 381                         ret = -ENOMEM;
 382                         goto out;
 383                 }
 384
 385                 link->file = file;
 386                 list_add_tail_rcu(&link->list, &tk->tp.files);
 387
 388                 tk->tp.flags |= TP_FLAG_TRACE;
 389         } else
 390                 tk->tp.flags |= TP_FLAG_PROFILE;
 391
 392         if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
 393                 if (trace_kprobe_is_return(tk))
 394                         ret = enable_kretprobe(&tk->rp);
 395                 else
 396                         ret = enable_kprobe(&tk->rp.kp);
 397         }
 398  out:
 399         return ret;
 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 trace_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_warn("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_warn("This probe might be able to register after target module is loaded. Continue.\n");
 482                         ret = 0;
 483                 } else if (ret == -EILSEQ) {
 484                         pr_warn("Probing address(0x%p) is not an instruction boundary.\n",
 485                                 tk->rp.kp.addr);
 486                         ret = -EINVAL;
 487                 }
 488         }
 489
 490         return ret;
 491 }
 492
 493 /* Internal unregister function - just handle k*probes and flags */
 494 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
 495 {
 496         if (trace_probe_is_registered(&tk->tp)) {
 497                 if (trace_kprobe_is_return(tk))
 498                         unregister_kretprobe(&tk->rp);
 499                 else
 500                         unregister_kprobe(&tk->rp.kp);
 501                 tk->tp.flags &= ~TP_FLAG_REGISTERED;
 502                 /* Cleanup kprobe for reuse */
 503                 if (tk->rp.kp.symbol_name)
 504                         tk->rp.kp.addr = NULL;
 505         }
 506 }
 507
 508 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
 509 static int unregister_trace_kprobe(struct trace_kprobe *tk)
 510 {
 511         /* Enabled event can not be unregistered */
 512         if (trace_probe_is_enabled(&tk->tp))
 513                 return -EBUSY;
 514
 515         /* Will fail if probe is being used by ftrace or perf */
 516         if (unregister_kprobe_event(tk))
 517                 return -EBUSY;
 518
 519         __unregister_trace_kprobe(tk);
 520         list_del(&tk->list);
 521
 522         return 0;
 523 }
 524
 525 /* Register a trace_probe and probe_event */
 526 static int register_trace_kprobe(struct trace_kprobe *tk)
 527 {
 528         struct trace_kprobe *old_tk;
 529         int ret;
 530
 531         mutex_lock(&probe_lock);
 532
 533         /* Delete old (same name) event if exist */
 534         old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call),
 535                         tk->tp.call.class->system);
 536         if (old_tk) {
 537                 ret = unregister_trace_kprobe(old_tk);
 538                 if (ret < 0)
 539                         goto end;
 540                 free_trace_kprobe(old_tk);
 541         }
 542
 543         /* Register new event */
 544         ret = register_kprobe_event(tk);
 545         if (ret) {
 546                 pr_warn("Failed to register probe event(%d)\n", ret);
 547                 goto end;
 548         }
 549
 550         /* Register k*probe */
 551         ret = __register_trace_kprobe(tk);
 552         if (ret < 0)
 553                 unregister_kprobe_event(tk);
 554         else
 555                 list_add_tail(&tk->list, &probe_list);
 556
 557 end:
 558         mutex_unlock(&probe_lock);
 559         return ret;
 560 }
 561
 562 /* Module notifier call back, checking event on the module */
 563 static int trace_kprobe_module_callback(struct notifier_block *nb,
 564                                        unsigned long val, void *data)
 565 {
 566         struct module *mod = data;
 567         struct trace_kprobe *tk;
 568         int ret;
 569
 570         if (val != MODULE_STATE_COMING)
 571                 return NOTIFY_DONE;
 572
 573         /* Update probes on coming module */
 574         mutex_lock(&probe_lock);
 575         list_for_each_entry(tk, &probe_list, list) {
 576                 if (trace_kprobe_within_module(tk, mod)) {
 577                         /* Don't need to check busy - this should have gone. */
 578                         __unregister_trace_kprobe(tk);
 579                         ret = __register_trace_kprobe(tk);
 580                         if (ret)
 581                                 pr_warn("Failed to re-register probe %s on %s: %d\n",
 582                                         trace_event_name(&tk->tp.call),
 583                                         mod->name, ret);
 584                 }
 585         }
 586         mutex_unlock(&probe_lock);
 587
 588         return NOTIFY_DONE;
 589 }
 590
 591 static struct notifier_block trace_kprobe_module_nb = {
 592         .notifier_call = trace_kprobe_module_callback,
 593         .priority = 1   /* Invoked after kprobe module callback */
 594 };
 595
 596 static int create_trace_kprobe(int argc, char **argv)
 597 {
 598         /*
 599          * Argument syntax:
 600          *  - Add kprobe: p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
 601          *  - Add kretprobe: r[:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
 602          * Fetch args:
 603          *  $retval     : fetch return value
 604          *  $stack      : fetch stack address
 605          *  $stackN     : fetch Nth of stack (N:0-)
 606          *  $comm       : fetch current task comm
 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                                                 kprobes_fetch_type_table);
 773                 if (ret) {
 774                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
 775                         goto error;
 776                 }
 777         }
 778
 779         ret = register_trace_kprobe(tk);
 780         if (ret)
 781                 goto error;
 782         return 0;
 783
 784 error:
 785         free_trace_kprobe(tk);
 786         return ret;
 787 }
 788
 789 static int release_all_trace_kprobes(void)
 790 {
 791         struct trace_kprobe *tk;
 792         int ret = 0;
 793
 794         mutex_lock(&probe_lock);
 795         /* Ensure no probe is in use. */
 796         list_for_each_entry(tk, &probe_list, list)
 797                 if (trace_probe_is_enabled(&tk->tp)) {
 798                         ret = -EBUSY;
 799                         goto end;
 800                 }
 801         /* TODO: Use batch unregistration */
 802         while (!list_empty(&probe_list)) {
 803                 tk = list_entry(probe_list.next, struct trace_kprobe, list);
 804                 ret = unregister_trace_kprobe(tk);
 805                 if (ret)
 806                         goto end;
 807                 free_trace_kprobe(tk);
 808         }
 809
 810 end:
 811         mutex_unlock(&probe_lock);
 812
 813         return ret;
 814 }
 815
 816 /* Probes listing interfaces */
 817 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
 818 {
 819         mutex_lock(&probe_lock);
 820         return seq_list_start(&probe_list, *pos);
 821 }
 822
 823 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
 824 {
 825         return seq_list_next(v, &probe_list, pos);
 826 }
 827
 828 static void probes_seq_stop(struct seq_file *m, void *v)
 829 {
 830         mutex_unlock(&probe_lock);
 831 }
 832
 833 static int probes_seq_show(struct seq_file *m, void *v)
 834 {
 835         struct trace_kprobe *tk = v;
 836         int i;
 837
 838         seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
 839         seq_printf(m, ":%s/%s", tk->tp.call.class->system,
 840                         trace_event_name(&tk->tp.call));
 841
 842         if (!tk->symbol)
 843                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
 844         else if (tk->rp.kp.offset)
 845                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
 846                            tk->rp.kp.offset);
 847         else
 848                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
 849
 850         for (i = 0; i < tk->tp.nr_args; i++)
 851                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
 852         seq_putc(m, '\n');
 853
 854         return 0;
 855 }
 856
 857 static const struct seq_operations probes_seq_op = {
 858         .start  = probes_seq_start,
 859         .next   = probes_seq_next,
 860         .stop   = probes_seq_stop,
 861         .show   = probes_seq_show
 862 };
 863
 864 static int probes_open(struct inode *inode, struct file *file)
 865 {
 866         int ret;
 867
 868         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
 869                 ret = release_all_trace_kprobes();
 870                 if (ret < 0)
 871                         return ret;
 872         }
 873
 874         return seq_open(file, &probes_seq_op);
 875 }
 876
 877 static ssize_t probes_write(struct file *file, const char __user *buffer,
 878                             size_t count, loff_t *ppos)
 879 {
 880         return traceprobe_probes_write(file, buffer, count, ppos,
 881                         create_trace_kprobe);
 882 }
 883
 884 static const struct file_operations kprobe_events_ops = {
 885         .owner          = THIS_MODULE,
 886         .open           = probes_open,
 887         .read           = seq_read,
 888         .llseek         = seq_lseek,
 889         .release        = seq_release,
 890         .write          = probes_write,
 891 };
 892
 893 /* Probes profiling interfaces */
 894 static int probes_profile_seq_show(struct seq_file *m, void *v)
 895 {
 896         struct trace_kprobe *tk = v;
 897
 898         seq_printf(m, "  %-44s %15lu %15lu\n",
 899                    trace_event_name(&tk->tp.call),
 900                    trace_kprobe_nhit(tk),
 901                    tk->rp.kp.nmissed);
 902
 903         return 0;
 904 }
 905
 906 static const struct seq_operations profile_seq_op = {
 907         .start  = probes_seq_start,
 908         .next   = probes_seq_next,
 909         .stop   = probes_seq_stop,
 910         .show   = probes_profile_seq_show
 911 };
 912
 913 static int profile_open(struct inode *inode, struct file *file)
 914 {
 915         return seq_open(file, &profile_seq_op);
 916 }
 917
 918 static const struct file_operations kprobe_profile_ops = {
 919         .owner          = THIS_MODULE,
 920         .open           = profile_open,
 921         .read           = seq_read,
 922         .llseek         = seq_lseek,
 923         .release        = seq_release,
 924 };
 925
 926 /* Kprobe handler */
 927 static nokprobe_inline void
 928 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
 929                     struct trace_event_file *trace_file)
 930 {
 931         struct kprobe_trace_entry_head *entry;
 932         struct ring_buffer_event *event;
 933         struct ring_buffer *buffer;
 934         int size, dsize, pc;
 935         unsigned long irq_flags;
 936         struct trace_event_call *call = &tk->tp.call;
 937
 938         WARN_ON(call != trace_file->event_call);
 939
 940         if (trace_trigger_soft_disabled(trace_file))
 941                 return;
 942
 943         local_save_flags(irq_flags);
 944         pc = preempt_count();
 945
 946         dsize = __get_data_size(&tk->tp, regs);
 947         size = sizeof(*entry) + tk->tp.size + dsize;
 948
 949         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
 950                                                 call->event.type,
 951                                                 size, irq_flags, pc);
 952         if (!event)
 953                 return;
 954
 955         entry = ring_buffer_event_data(event);
 956         entry->ip = (unsigned long)tk->rp.kp.addr;
 957         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
 958
 959         event_trigger_unlock_commit_regs(trace_file, buffer, event,
 960                                          entry, irq_flags, pc, regs);
 961 }
 962
 963 static void
 964 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
 965 {
 966         struct event_file_link *link;
 967
 968         list_for_each_entry_rcu(link, &tk->tp.files, list)
 969                 __kprobe_trace_func(tk, regs, link->file);
 970 }
 971 NOKPROBE_SYMBOL(kprobe_trace_func);
 972
 973 /* Kretprobe handler */
 974 static nokprobe_inline void
 975 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
 976                        struct pt_regs *regs,
 977                        struct trace_event_file *trace_file)
 978 {
 979         struct kretprobe_trace_entry_head *entry;
 980         struct ring_buffer_event *event;
 981         struct ring_buffer *buffer;
 982         int size, pc, dsize;
 983         unsigned long irq_flags;
 984         struct trace_event_call *call = &tk->tp.call;
 985
 986         WARN_ON(call != trace_file->event_call);
 987
 988         if (trace_trigger_soft_disabled(trace_file))
 989                 return;
 990
 991         local_save_flags(irq_flags);
 992         pc = preempt_count();
 993
 994         dsize = __get_data_size(&tk->tp, regs);
 995         size = sizeof(*entry) + tk->tp.size + dsize;
 996
 997         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
 998                                                 call->event.type,
 999                                                 size, irq_flags, pc);
1000         if (!event)
1001                 return;
1002
1003         entry = ring_buffer_event_data(event);
1004         entry->func = (unsigned long)tk->rp.kp.addr;
1005         entry->ret_ip = (unsigned long)ri->ret_addr;
1006         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1007
1008         event_trigger_unlock_commit_regs(trace_file, buffer, event,
1009                                          entry, irq_flags, pc, regs);
1010 }
1011
1012 static void
1013 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1014                      struct pt_regs *regs)
1015 {
1016         struct event_file_link *link;
1017
1018         list_for_each_entry_rcu(link, &tk->tp.files, list)
1019                 __kretprobe_trace_func(tk, ri, regs, link->file);
1020 }
1021 NOKPROBE_SYMBOL(kretprobe_trace_func);
1022
1023 /* Event entry printers */
1024 static enum print_line_t
1025 print_kprobe_event(struct trace_iterator *iter, int flags,
1026                    struct trace_event *event)
1027 {
1028         struct kprobe_trace_entry_head *field;
1029         struct trace_seq *s = &iter->seq;
1030         struct trace_probe *tp;
1031         u8 *data;
1032         int i;
1033
1034         field = (struct kprobe_trace_entry_head *)iter->ent;
1035         tp = container_of(event, struct trace_probe, call.event);
1036
1037         trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1038
1039         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1040                 goto out;
1041
1042         trace_seq_putc(s, ')');
1043
1044         data = (u8 *)&field[1];
1045         for (i = 0; i < tp->nr_args; i++)
1046                 if (!tp->args[i].type->print(s, tp->args[i].name,
1047                                              data + tp->args[i].offset, field))
1048                         goto out;
1049
1050         trace_seq_putc(s, '\n');
1051  out:
1052         return trace_handle_return(s);
1053 }
1054
1055 static enum print_line_t
1056 print_kretprobe_event(struct trace_iterator *iter, int flags,
1057                       struct trace_event *event)
1058 {
1059         struct kretprobe_trace_entry_head *field;
1060         struct trace_seq *s = &iter->seq;
1061         struct trace_probe *tp;
1062         u8 *data;
1063         int i;
1064
1065         field = (struct kretprobe_trace_entry_head *)iter->ent;
1066         tp = container_of(event, struct trace_probe, call.event);
1067
1068         trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1069
1070         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1071                 goto out;
1072
1073         trace_seq_puts(s, " <- ");
1074
1075         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1076                 goto out;
1077
1078         trace_seq_putc(s, ')');
1079
1080         data = (u8 *)&field[1];
1081         for (i = 0; i < tp->nr_args; i++)
1082                 if (!tp->args[i].type->print(s, tp->args[i].name,
1083                                              data + tp->args[i].offset, field))
1084                         goto out;
1085
1086         trace_seq_putc(s, '\n');
1087
1088  out:
1089         return trace_handle_return(s);
1090 }
1091
1092
1093 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1094 {
1095         int ret, i;
1096         struct kprobe_trace_entry_head field;
1097         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1098
1099         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1100         /* Set argument names as fields */
1101         for (i = 0; i < tk->tp.nr_args; i++) {
1102                 struct probe_arg *parg = &tk->tp.args[i];
1103
1104                 ret = trace_define_field(event_call, parg->type->fmttype,
1105                                          parg->name,
1106                                          sizeof(field) + parg->offset,
1107                                          parg->type->size,
1108                                          parg->type->is_signed,
1109                                          FILTER_OTHER);
1110                 if (ret)
1111                         return ret;
1112         }
1113         return 0;
1114 }
1115
1116 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1117 {
1118         int ret, i;
1119         struct kretprobe_trace_entry_head field;
1120         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1121
1122         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1123         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1124         /* Set argument names as fields */
1125         for (i = 0; i < tk->tp.nr_args; i++) {
1126                 struct probe_arg *parg = &tk->tp.args[i];
1127
1128                 ret = trace_define_field(event_call, parg->type->fmttype,
1129                                          parg->name,
1130                                          sizeof(field) + parg->offset,
1131                                          parg->type->size,
1132                                          parg->type->is_signed,
1133                                          FILTER_OTHER);
1134                 if (ret)
1135                         return ret;
1136         }
1137         return 0;
1138 }
1139
1140 #ifdef CONFIG_PERF_EVENTS
1141
1142 /* Kprobe profile handler */
1143 static void
1144 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1145 {
1146         struct trace_event_call *call = &tk->tp.call;
1147         struct bpf_prog *prog = call->prog;
1148         struct kprobe_trace_entry_head *entry;
1149         struct hlist_head *head;
1150         int size, __size, dsize;
1151         int rctx;
1152
1153         if (prog && !trace_call_bpf(prog, regs))
1154                 return;
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_alloc(size, NULL, &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, call->event.type, 1, regs,
1173                               head, NULL);
1174 }
1175 NOKPROBE_SYMBOL(kprobe_perf_func);
1176
1177 /* Kretprobe profile handler */
1178 static void
1179 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1180                     struct pt_regs *regs)
1181 {
1182         struct trace_event_call *call = &tk->tp.call;
1183         struct bpf_prog *prog = call->prog;
1184         struct kretprobe_trace_entry_head *entry;
1185         struct hlist_head *head;
1186         int size, __size, dsize;
1187         int rctx;
1188
1189         if (prog && !trace_call_bpf(prog, regs))
1190                 return;
1191
1192         head = this_cpu_ptr(call->perf_events);
1193         if (hlist_empty(head))
1194                 return;
1195
1196         dsize = __get_data_size(&tk->tp, regs);
1197         __size = sizeof(*entry) + tk->tp.size + dsize;
1198         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1199         size -= sizeof(u32);
1200
1201         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1202         if (!entry)
1203                 return;
1204
1205         entry->func = (unsigned long)tk->rp.kp.addr;
1206         entry->ret_ip = (unsigned long)ri->ret_addr;
1207         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1208         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1209                               head, NULL);
1210 }
1211 NOKPROBE_SYMBOL(kretprobe_perf_func);
1212 #endif  /* CONFIG_PERF_EVENTS */
1213
1214 /*
1215  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1216  *
1217  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1218  * lockless, but we can't race with this __init function.
1219  */
1220 static int kprobe_register(struct trace_event_call *event,
1221                            enum trace_reg type, void *data)
1222 {
1223         struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1224         struct trace_event_file *file = data;
1225
1226         switch (type) {
1227         case TRACE_REG_REGISTER:
1228                 return enable_trace_kprobe(tk, file);
1229         case TRACE_REG_UNREGISTER:
1230                 return disable_trace_kprobe(tk, file);
1231
1232 #ifdef CONFIG_PERF_EVENTS
1233         case TRACE_REG_PERF_REGISTER:
1234                 return enable_trace_kprobe(tk, NULL);
1235         case TRACE_REG_PERF_UNREGISTER:
1236                 return disable_trace_kprobe(tk, NULL);
1237         case TRACE_REG_PERF_OPEN:
1238         case TRACE_REG_PERF_CLOSE:
1239         case TRACE_REG_PERF_ADD:
1240         case TRACE_REG_PERF_DEL:
1241                 return 0;
1242 #endif
1243         }
1244         return 0;
1245 }
1246
1247 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1248 {
1249         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1250
1251         raw_cpu_inc(*tk->nhit);
1252
1253         if (tk->tp.flags & TP_FLAG_TRACE)
1254                 kprobe_trace_func(tk, regs);
1255 #ifdef CONFIG_PERF_EVENTS
1256         if (tk->tp.flags & TP_FLAG_PROFILE)
1257                 kprobe_perf_func(tk, regs);
1258 #endif
1259         return 0;       /* We don't tweek kernel, so just return 0 */
1260 }
1261 NOKPROBE_SYMBOL(kprobe_dispatcher);
1262
1263 static int
1264 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1265 {
1266         struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1267
1268         raw_cpu_inc(*tk->nhit);
1269
1270         if (tk->tp.flags & TP_FLAG_TRACE)
1271                 kretprobe_trace_func(tk, ri, regs);
1272 #ifdef CONFIG_PERF_EVENTS
1273         if (tk->tp.flags & TP_FLAG_PROFILE)
1274                 kretprobe_perf_func(tk, ri, regs);
1275 #endif
1276         return 0;       /* We don't tweek kernel, so just return 0 */
1277 }
1278 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1279
1280 static struct trace_event_functions kretprobe_funcs = {
1281         .trace          = print_kretprobe_event
1282 };
1283
1284 static struct trace_event_functions kprobe_funcs = {
1285         .trace          = print_kprobe_event
1286 };
1287
1288 static int register_kprobe_event(struct trace_kprobe *tk)
1289 {
1290         struct trace_event_call *call = &tk->tp.call;
1291         int ret;
1292
1293         /* Initialize trace_event_call */
1294         INIT_LIST_HEAD(&call->class->fields);
1295         if (trace_kprobe_is_return(tk)) {
1296                 call->event.funcs = &kretprobe_funcs;
1297                 call->class->define_fields = kretprobe_event_define_fields;
1298         } else {
1299                 call->event.funcs = &kprobe_funcs;
1300                 call->class->define_fields = kprobe_event_define_fields;
1301         }
1302         if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1303                 return -ENOMEM;
1304         ret = register_trace_event(&call->event);
1305         if (!ret) {
1306                 kfree(call->print_fmt);
1307                 return -ENODEV;
1308         }
1309         call->flags = TRACE_EVENT_FL_KPROBE;
1310         call->class->reg = kprobe_register;
1311         call->data = tk;
1312         ret = trace_add_event_call(call);
1313         if (ret) {
1314                 pr_info("Failed to register kprobe event: %s\n",
1315                         trace_event_name(call));
1316                 kfree(call->print_fmt);
1317                 unregister_trace_event(&call->event);
1318         }
1319         return ret;
1320 }
1321
1322 static int unregister_kprobe_event(struct trace_kprobe *tk)
1323 {
1324         int ret;
1325
1326         /* tp->event is unregistered in trace_remove_event_call() */
1327         ret = trace_remove_event_call(&tk->tp.call);
1328         if (!ret)
1329                 kfree(tk->tp.call.print_fmt);
1330         return ret;
1331 }
1332
1333 /* Make a tracefs interface for controlling probe points */
1334 static __init int init_kprobe_trace(void)
1335 {
1336         struct dentry *d_tracer;
1337         struct dentry *entry;
1338
1339         if (register_module_notifier(&trace_kprobe_module_nb))
1340                 return -EINVAL;
1341
1342         d_tracer = tracing_init_dentry();
1343         if (IS_ERR(d_tracer))
1344                 return 0;
1345
1346         entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1347                                     NULL, &kprobe_events_ops);
1348
1349         /* Event list interface */
1350         if (!entry)
1351                 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1352
1353         /* Profile interface */
1354         entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1355                                     NULL, &kprobe_profile_ops);
1356
1357         if (!entry)
1358                 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1359         return 0;
1360 }
1361 fs_initcall(init_kprobe_trace);
1362
1363
1364 #ifdef CONFIG_FTRACE_STARTUP_TEST
1365 /*
1366  * The "__used" keeps gcc from removing the function symbol
1367  * from the kallsyms table. 'noinline' makes sure that there
1368  * isn't an inlined version used by the test method below
1369  */
1370 static __used __init noinline int
1371 kprobe_trace_selftest_target(int a1, int a2, int a3, int a4, int a5, int a6)
1372 {
1373         return a1 + a2 + a3 + a4 + a5 + a6;
1374 }
1375
1376 static __init struct trace_event_file *
1377 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1378 {
1379         struct trace_event_file *file;
1380
1381         list_for_each_entry(file, &tr->events, list)
1382                 if (file->event_call == &tk->tp.call)
1383                         return file;
1384
1385         return NULL;
1386 }
1387
1388 /*
1389  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1390  * stage, we can do this lockless.
1391  */
1392 static __init int kprobe_trace_self_tests_init(void)
1393 {
1394         int ret, warn = 0;
1395         int (*target)(int, int, int, int, int, int);
1396         struct trace_kprobe *tk;
1397         struct trace_event_file *file;
1398
1399         if (tracing_is_disabled())
1400                 return -ENODEV;
1401
1402         target = kprobe_trace_selftest_target;
1403
1404         pr_info("Testing kprobe tracing: ");
1405
1406         ret = traceprobe_command("p:testprobe kprobe_trace_selftest_target "
1407                                   "$stack $stack0 +0($stack)",
1408                                   create_trace_kprobe);
1409         if (WARN_ON_ONCE(ret)) {
1410                 pr_warn("error on probing function entry.\n");
1411                 warn++;
1412         } else {
1413                 /* Enable trace point */
1414                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1415                 if (WARN_ON_ONCE(tk == NULL)) {
1416                         pr_warn("error on getting new probe.\n");
1417                         warn++;
1418                 } else {
1419                         file = find_trace_probe_file(tk, top_trace_array());
1420                         if (WARN_ON_ONCE(file == NULL)) {
1421                                 pr_warn("error on getting probe file.\n");
1422                                 warn++;
1423                         } else
1424                                 enable_trace_kprobe(tk, file);
1425                 }
1426         }
1427
1428         ret = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target "
1429                                   "$retval", create_trace_kprobe);
1430         if (WARN_ON_ONCE(ret)) {
1431                 pr_warn("error on probing function return.\n");
1432                 warn++;
1433         } else {
1434                 /* Enable trace point */
1435                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1436                 if (WARN_ON_ONCE(tk == NULL)) {
1437                         pr_warn("error on getting 2nd new probe.\n");
1438                         warn++;
1439                 } else {
1440                         file = find_trace_probe_file(tk, top_trace_array());
1441                         if (WARN_ON_ONCE(file == NULL)) {
1442                                 pr_warn("error on getting probe file.\n");
1443                                 warn++;
1444                         } else
1445                                 enable_trace_kprobe(tk, file);
1446                 }
1447         }
1448
1449         if (warn)
1450                 goto end;
1451
1452         ret = target(1, 2, 3, 4, 5, 6);
1453
1454         /*
1455          * Not expecting an error here, the check is only to prevent the
1456          * optimizer from removing the call to target() as otherwise there
1457          * are no side-effects and the call is never performed.
1458          */
1459         if (ret != 21)
1460                 warn++;
1461
1462         /* Disable trace points before removing it */
1463         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1464         if (WARN_ON_ONCE(tk == NULL)) {
1465                 pr_warn("error on getting test probe.\n");
1466                 warn++;
1467         } else {
1468                 if (trace_kprobe_nhit(tk) != 1) {
1469                         pr_warn("incorrect number of testprobe hits\n");
1470                         warn++;
1471                 }
1472
1473                 file = find_trace_probe_file(tk, top_trace_array());
1474                 if (WARN_ON_ONCE(file == NULL)) {
1475                         pr_warn("error on getting probe file.\n");
1476                         warn++;
1477                 } else
1478                         disable_trace_kprobe(tk, file);
1479         }
1480
1481         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1482         if (WARN_ON_ONCE(tk == NULL)) {
1483                 pr_warn("error on getting 2nd test probe.\n");
1484                 warn++;
1485         } else {
1486                 if (trace_kprobe_nhit(tk) != 1) {
1487                         pr_warn("incorrect number of testprobe2 hits\n");
1488                         warn++;
1489                 }
1490
1491                 file = find_trace_probe_file(tk, top_trace_array());
1492                 if (WARN_ON_ONCE(file == NULL)) {
1493                         pr_warn("error on getting probe file.\n");
1494                         warn++;
1495                 } else
1496                         disable_trace_kprobe(tk, file);
1497         }
1498
1499         ret = traceprobe_command("-:testprobe", create_trace_kprobe);
1500         if (WARN_ON_ONCE(ret)) {
1501                 pr_warn("error on deleting a probe.\n");
1502                 warn++;
1503         }
1504
1505         ret = traceprobe_command("-:testprobe2", create_trace_kprobe);
1506         if (WARN_ON_ONCE(ret)) {
1507                 pr_warn("error on deleting a probe.\n");
1508                 warn++;
1509         }
1510
1511 end:
1512         release_all_trace_kprobes();
1513         if (warn)
1514                 pr_cont("NG: Some tests are failed. Please check them.\n");
1515         else
1516                 pr_cont("OK\n");
1517         return 0;
1518 }
1519
1520 late_initcall(kprobe_trace_self_tests_init);
1521
1522 #endif