kernel/trace/trace_kprobe.c

   1 /*
   2  * Kprobes-based tracing events
   3  *
   4  * Created by Masami Hiramatsu <mhiramat@redhat.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/uaccess.h>
  22
  23 #include "trace_probe.h"
  24
  25 #define KPROBE_EVENT_SYSTEM "kprobes"
  26
  27 /**
  28  * Kprobe event core functions
  29  */
  30 struct trace_kprobe {
  31         struct list_head        list;
  32         struct kretprobe        rp;     /* Use rp.kp for kprobe use */
  33         unsigned long           nhit;
  34         const char              *symbol;        /* symbol name */
  35         struct trace_probe      tp;
  36 };
  37
  38 #define SIZEOF_TRACE_KPROBE(n)                          \
  39         (offsetof(struct trace_kprobe, tp.args) +       \
  40         (sizeof(struct probe_arg) * (n)))
  41
  42
  43 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
  44 {
  45         return tk->rp.handler != NULL;
  46 }
  47
  48 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
  49 {
  50         return tk->symbol ? tk->symbol : "unknown";
  51 }
  52
  53 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
  54 {
  55         return tk->rp.kp.offset;
  56 }
  57
  58 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
  59 {
  60         return !!(kprobe_gone(&tk->rp.kp));
  61 }
  62
  63 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
  64                                                  struct module *mod)
  65 {
  66         int len = strlen(mod->name);
  67         const char *name = trace_kprobe_symbol(tk);
  68         return strncmp(mod->name, name, len) == 0 && name[len] == ':';
  69 }
  70
  71 static nokprobe_inline bool trace_kprobe_is_on_module(struct trace_kprobe *tk)
  72 {
  73         return !!strchr(trace_kprobe_symbol(tk), ':');
  74 }
  75
  76 static int register_kprobe_event(struct trace_kprobe *tk);
  77 static int unregister_kprobe_event(struct trace_kprobe *tk);
  78
  79 static DEFINE_MUTEX(probe_lock);
  80 static LIST_HEAD(probe_list);
  81
  82 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
  83 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
  84                                 struct pt_regs *regs);
  85
  86 /* Memory fetching by symbol */
  87 struct symbol_cache {
  88         char            *symbol;
  89         long            offset;
  90         unsigned long   addr;
  91 };
  92
  93 unsigned long update_symbol_cache(struct symbol_cache *sc)
  94 {
  95         sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
  96
  97         if (sc->addr)
  98                 sc->addr += sc->offset;
  99
 100         return sc->addr;
 101 }
 102
 103 void free_symbol_cache(struct symbol_cache *sc)
 104 {
 105         kfree(sc->symbol);
 106         kfree(sc);
 107 }
 108
 109 struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
 110 {
 111         struct symbol_cache *sc;
 112
 113         if (!sym || strlen(sym) == 0)
 114                 return NULL;
 115
 116         sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
 117         if (!sc)
 118                 return NULL;
 119
 120         sc->symbol = kstrdup(sym, GFP_KERNEL);
 121         if (!sc->symbol) {
 122                 kfree(sc);
 123                 return NULL;
 124         }
 125         sc->offset = offset;
 126         update_symbol_cache(sc);
 127
 128         return sc;
 129 }
 130
 131 /*
 132  * Kprobes-specific fetch functions
 133  */
 134 #define DEFINE_FETCH_stack(type)                                        \
 135 static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,          \
 136                                           void *offset, void *dest)     \
 137 {                                                                       \
 138         *(type *)dest = (type)regs_get_kernel_stack_nth(regs,           \
 139                                 (unsigned int)((unsigned long)offset)); \
 140 }                                                                       \
 141 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(stack, type));
 142
 143 DEFINE_BASIC_FETCH_FUNCS(stack)
 144 /* No string on the stack entry */
 145 #define fetch_stack_string      NULL
 146 #define fetch_stack_string_size NULL
 147
 148 #define DEFINE_FETCH_memory(type)                                       \
 149 static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,         \
 150                                           void *addr, void *dest)       \
 151 {                                                                       \
 152         type retval;                                                    \
 153         if (probe_kernel_address(addr, retval))                         \
 154                 *(type *)dest = 0;                                      \
 155         else                                                            \
 156                 *(type *)dest = retval;                                 \
 157 }                                                                       \
 158 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, type));
 159
 160 DEFINE_BASIC_FETCH_FUNCS(memory)
 161 /*
 162  * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
 163  * length and relative data location.
 164  */
 165 static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
 166                                             void *addr, void *dest)
 167 {
 168         int maxlen = get_rloc_len(*(u32 *)dest);
 169         u8 *dst = get_rloc_data(dest);
 170         long ret;
 171
 172         if (!maxlen)
 173                 return;
 174
 175         /*
 176          * Try to get string again, since the string can be changed while
 177          * probing.
 178          */
 179         ret = strncpy_from_unsafe(dst, addr, maxlen);
 180
 181         if (ret < 0) {  /* Failed to fetch string */
 182                 dst[0] = '\0';
 183                 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
 184         } else {
 185                 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
 186         }
 187 }
 188 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string));
 189
 190 /* Return the length of string -- including null terminal byte */
 191 static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
 192                                                  void *addr, void *dest)
 193 {
 194         mm_segment_t old_fs;
 195         int ret, len = 0;
 196         u8 c;
 197
 198         old_fs = get_fs();
 199         set_fs(KERNEL_DS);
 200         pagefault_disable();
 201
 202         do {
 203                 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
 204                 len++;
 205         } while (c && ret == 0 && len < MAX_STRING_SIZE);
 206
 207         pagefault_enable();
 208         set_fs(old_fs);
 209
 210         if (ret < 0)    /* Failed to check the length */
 211                 *(u32 *)dest = 0;
 212         else
 213                 *(u32 *)dest = len;
 214 }
 215 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string_size));
 216
 217 #define DEFINE_FETCH_symbol(type)                                       \
 218 void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs, void *data, void *dest)\
 219 {                                                                       \
 220         struct symbol_cache *sc = data;                                 \
 221         if (sc->addr)                                                   \
 222                 fetch_memory_##type(regs, (void *)sc->addr, dest);      \
 223         else                                                            \
 224                 *(type *)dest = 0;                                      \
 225 }                                                                       \
 226 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(symbol, type));
 227
 228 DEFINE_BASIC_FETCH_FUNCS(symbol)
 229 DEFINE_FETCH_symbol(string)
 230 DEFINE_FETCH_symbol(string_size)
 231
 232 /* kprobes don't support file_offset fetch methods */
 233 #define fetch_file_offset_u8            NULL
 234 #define fetch_file_offset_u16           NULL
 235 #define fetch_file_offset_u32           NULL
 236 #define fetch_file_offset_u64           NULL
 237 #define fetch_file_offset_string        NULL
 238 #define fetch_file_offset_string_size   NULL
 239
 240 /* Fetch type information table */
 241 static const struct fetch_type kprobes_fetch_type_table[] = {
 242         /* Special types */
 243         [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
 244                                         sizeof(u32), 1, "__data_loc char[]"),
 245         [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
 246                                         string_size, sizeof(u32), 0, "u32"),
 247         /* Basic types */
 248         ASSIGN_FETCH_TYPE(u8,  u8,  0),
 249         ASSIGN_FETCH_TYPE(u16, u16, 0),
 250         ASSIGN_FETCH_TYPE(u32, u32, 0),
 251         ASSIGN_FETCH_TYPE(u64, u64, 0),
 252         ASSIGN_FETCH_TYPE(s8,  u8,  1),
 253         ASSIGN_FETCH_TYPE(s16, u16, 1),
 254         ASSIGN_FETCH_TYPE(s32, u32, 1),
 255         ASSIGN_FETCH_TYPE(s64, u64, 1),
 256
 257         ASSIGN_FETCH_TYPE_END
 258 };
 259
 260 /*
 261  * Allocate new trace_probe and initialize it (including kprobes).
 262  */
 263 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
 264                                              const char *event,
 265                                              void *addr,
 266                                              const char *symbol,
 267                                              unsigned long offs,
 268                                              int nargs, bool is_return)
 269 {
 270         struct trace_kprobe *tk;
 271         int ret = -ENOMEM;
 272
 273         tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
 274         if (!tk)
 275                 return ERR_PTR(ret);
 276
 277         if (symbol) {
 278                 tk->symbol = kstrdup(symbol, GFP_KERNEL);
 279                 if (!tk->symbol)
 280                         goto error;
 281                 tk->rp.kp.symbol_name = tk->symbol;
 282                 tk->rp.kp.offset = offs;
 283         } else
 284                 tk->rp.kp.addr = addr;
 285
 286         if (is_return)
 287                 tk->rp.handler = kretprobe_dispatcher;
 288         else
 289                 tk->rp.kp.pre_handler = kprobe_dispatcher;
 290
 291         if (!event || !is_good_name(event)) {
 292                 ret = -EINVAL;
 293                 goto error;
 294         }
 295
 296         tk->tp.call.class = &tk->tp.class;
 297         tk->tp.call.name = kstrdup(event, GFP_KERNEL);
 298         if (!tk->tp.call.name)
 299                 goto error;
 300
 301         if (!group || !is_good_name(group)) {
 302                 ret = -EINVAL;
 303                 goto error;
 304         }
 305
 306         tk->tp.class.system = kstrdup(group, GFP_KERNEL);
 307         if (!tk->tp.class.system)
 308                 goto error;
 309
 310         INIT_LIST_HEAD(&tk->list);
 311         INIT_LIST_HEAD(&tk->tp.files);
 312         return tk;
 313 error:
 314         kfree(tk->tp.call.name);
 315         kfree(tk->symbol);
 316         kfree(tk);
 317         return ERR_PTR(ret);
 318 }
 319
 320 static void free_trace_kprobe(struct trace_kprobe *tk)
 321 {
 322         int i;
 323
 324         for (i = 0; i < tk->tp.nr_args; i++)
 325                 traceprobe_free_probe_arg(&tk->tp.args[i]);
 326
 327         kfree(tk->tp.call.class->system);
 328         kfree(tk->tp.call.name);
 329         kfree(tk->symbol);
 330         kfree(tk);
 331 }
 332
 333 static struct trace_kprobe *find_trace_kprobe(const char *event,
 334                                               const char *group)
 335 {
 336         struct trace_kprobe *tk;
 337
 338         list_for_each_entry(tk, &probe_list, list)
 339                 if (strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
 340                     strcmp(tk->tp.call.class->system, group) == 0)
 341                         return tk;
 342         return NULL;
 343 }
 344
 345 /*
 346  * Enable trace_probe
 347  * if the file is NULL, enable "perf" handler, or enable "trace" handler.
 348  */
 349 static int
 350 enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
 351 {
 352         int ret = 0;
 353
 354         if (file) {
 355                 struct event_file_link *link;
 356
 357                 link = kmalloc(sizeof(*link), GFP_KERNEL);
 358                 if (!link) {
 359                         ret = -ENOMEM;
 360                         goto out;
 361                 }
 362
 363                 link->file = file;
 364                 list_add_tail_rcu(&link->list, &tk->tp.files);
 365
 366                 tk->tp.flags |= TP_FLAG_TRACE;
 367         } else
 368                 tk->tp.flags |= TP_FLAG_PROFILE;
 369
 370         if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
 371                 if (trace_kprobe_is_return(tk))
 372                         ret = enable_kretprobe(&tk->rp);
 373                 else
 374                         ret = enable_kprobe(&tk->rp.kp);
 375         }
 376  out:
 377         return ret;
 378 }
 379
 380 /*
 381  * Disable trace_probe
 382  * if the file is NULL, disable "perf" handler, or disable "trace" handler.
 383  */
 384 static int
 385 disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
 386 {
 387         struct event_file_link *link = NULL;
 388         int wait = 0;
 389         int ret = 0;
 390
 391         if (file) {
 392                 link = find_event_file_link(&tk->tp, file);
 393                 if (!link) {
 394                         ret = -EINVAL;
 395                         goto out;
 396                 }
 397
 398                 list_del_rcu(&link->list);
 399                 wait = 1;
 400                 if (!list_empty(&tk->tp.files))
 401                         goto out;
 402
 403                 tk->tp.flags &= ~TP_FLAG_TRACE;
 404         } else
 405                 tk->tp.flags &= ~TP_FLAG_PROFILE;
 406
 407         if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
 408                 if (trace_kprobe_is_return(tk))
 409                         disable_kretprobe(&tk->rp);
 410                 else
 411                         disable_kprobe(&tk->rp.kp);
 412                 wait = 1;
 413         }
 414  out:
 415         if (wait) {
 416                 /*
 417                  * Synchronize with kprobe_trace_func/kretprobe_trace_func
 418                  * to ensure disabled (all running handlers are finished).
 419                  * This is not only for kfree(), but also the caller,
 420                  * trace_remove_event_call() supposes it for releasing
 421                  * event_call related objects, which will be accessed in
 422                  * the kprobe_trace_func/kretprobe_trace_func.
 423                  */
 424                 synchronize_sched();
 425                 kfree(link);    /* Ignored if link == NULL */
 426         }
 427
 428         return ret;
 429 }
 430
 431 /* Internal register function - just handle k*probes and flags */
 432 static int __register_trace_kprobe(struct trace_kprobe *tk)
 433 {
 434         int i, ret;
 435
 436         if (trace_probe_is_registered(&tk->tp))
 437                 return -EINVAL;
 438
 439         for (i = 0; i < tk->tp.nr_args; i++)
 440                 traceprobe_update_arg(&tk->tp.args[i]);
 441
 442         /* Set/clear disabled flag according to tp->flag */
 443         if (trace_probe_is_enabled(&tk->tp))
 444                 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
 445         else
 446                 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 447
 448         if (trace_kprobe_is_return(tk))
 449                 ret = register_kretprobe(&tk->rp);
 450         else
 451                 ret = register_kprobe(&tk->rp.kp);
 452
 453         if (ret == 0)
 454                 tk->tp.flags |= TP_FLAG_REGISTERED;
 455         else {
 456                 pr_warning("Could not insert probe at %s+%lu: %d\n",
 457                            trace_kprobe_symbol(tk), trace_kprobe_offset(tk), ret);
 458                 if (ret == -ENOENT && trace_kprobe_is_on_module(tk)) {
 459                         pr_warning("This probe might be able to register after"
 460                                    "target module is loaded. Continue.\n");
 461                         ret = 0;
 462                 } else if (ret == -EILSEQ) {
 463                         pr_warning("Probing address(0x%p) is not an "
 464                                    "instruction boundary.\n",
 465                                    tk->rp.kp.addr);
 466                         ret = -EINVAL;
 467                 }
 468         }
 469
 470         return ret;
 471 }
 472
 473 /* Internal unregister function - just handle k*probes and flags */
 474 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
 475 {
 476         if (trace_probe_is_registered(&tk->tp)) {
 477                 if (trace_kprobe_is_return(tk))
 478                         unregister_kretprobe(&tk->rp);
 479                 else
 480                         unregister_kprobe(&tk->rp.kp);
 481                 tk->tp.flags &= ~TP_FLAG_REGISTERED;
 482                 /* Cleanup kprobe for reuse */
 483                 if (tk->rp.kp.symbol_name)
 484                         tk->rp.kp.addr = NULL;
 485         }
 486 }
 487
 488 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
 489 static int unregister_trace_kprobe(struct trace_kprobe *tk)
 490 {
 491         /* Enabled event can not be unregistered */
 492         if (trace_probe_is_enabled(&tk->tp))
 493                 return -EBUSY;
 494
 495         /* Will fail if probe is being used by ftrace or perf */
 496         if (unregister_kprobe_event(tk))
 497                 return -EBUSY;
 498
 499         __unregister_trace_kprobe(tk);
 500         list_del(&tk->list);
 501
 502         return 0;
 503 }
 504
 505 /* Register a trace_probe and probe_event */
 506 static int register_trace_kprobe(struct trace_kprobe *tk)
 507 {
 508         struct trace_kprobe *old_tk;
 509         int ret;
 510
 511         mutex_lock(&probe_lock);
 512
 513         /* Delete old (same name) event if exist */
 514         old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call),
 515                         tk->tp.call.class->system);
 516         if (old_tk) {
 517                 ret = unregister_trace_kprobe(old_tk);
 518                 if (ret < 0)
 519                         goto end;
 520                 free_trace_kprobe(old_tk);
 521         }
 522
 523         /* Register new event */
 524         ret = register_kprobe_event(tk);
 525         if (ret) {
 526                 pr_warning("Failed to register probe event(%d)\n", ret);
 527                 goto end;
 528         }
 529
 530         /* Register k*probe */
 531         ret = __register_trace_kprobe(tk);
 532         if (ret < 0)
 533                 unregister_kprobe_event(tk);
 534         else
 535                 list_add_tail(&tk->list, &probe_list);
 536
 537 end:
 538         mutex_unlock(&probe_lock);
 539         return ret;
 540 }
 541
 542 /* Module notifier call back, checking event on the module */
 543 static int trace_kprobe_module_callback(struct notifier_block *nb,
 544                                        unsigned long val, void *data)
 545 {
 546         struct module *mod = data;
 547         struct trace_kprobe *tk;
 548         int ret;
 549
 550         if (val != MODULE_STATE_COMING)
 551                 return NOTIFY_DONE;
 552
 553         /* Update probes on coming module */
 554         mutex_lock(&probe_lock);
 555         list_for_each_entry(tk, &probe_list, list) {
 556                 if (trace_kprobe_within_module(tk, mod)) {
 557                         /* Don't need to check busy - this should have gone. */
 558                         __unregister_trace_kprobe(tk);
 559                         ret = __register_trace_kprobe(tk);
 560                         if (ret)
 561                                 pr_warning("Failed to re-register probe %s on"
 562                                            "%s: %d\n",
 563                                            trace_event_name(&tk->tp.call),
 564                                            mod->name, ret);
 565                 }
 566         }
 567         mutex_unlock(&probe_lock);
 568
 569         return NOTIFY_DONE;
 570 }
 571
 572 static struct notifier_block trace_kprobe_module_nb = {
 573         .notifier_call = trace_kprobe_module_callback,
 574         .priority = 1   /* Invoked after kprobe module callback */
 575 };
 576
 577 static int create_trace_kprobe(int argc, char **argv)
 578 {
 579         /*
 580          * Argument syntax:
 581          *  - Add kprobe: p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
 582          *  - Add kretprobe: r[:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
 583          * Fetch args:
 584          *  $retval     : fetch return value
 585          *  $stack      : fetch stack address
 586          *  $stackN     : fetch Nth of stack (N:0-)
 587          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 588          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 589          *  %REG        : fetch register REG
 590          * Dereferencing memory fetch:
 591          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 592          * Alias name of args:
 593          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 594          * Type of args:
 595          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 596          */
 597         struct trace_kprobe *tk;
 598         int i, ret = 0;
 599         bool is_return = false, is_delete = false;
 600         char *symbol = NULL, *event = NULL, *group = NULL;
 601         char *arg;
 602         unsigned long offset = 0;
 603         void *addr = NULL;
 604         char buf[MAX_EVENT_NAME_LEN];
 605
 606         /* argc must be >= 1 */
 607         if (argv[0][0] == 'p')
 608                 is_return = false;
 609         else if (argv[0][0] == 'r')
 610                 is_return = true;
 611         else if (argv[0][0] == '-')
 612                 is_delete = true;
 613         else {
 614                 pr_info("Probe definition must be started with 'p', 'r' or"
 615                         " '-'.\n");
 616                 return -EINVAL;
 617         }
 618
 619         if (argv[0][1] == ':') {
 620                 event = &argv[0][2];
 621                 if (strchr(event, '/')) {
 622                         group = event;
 623                         event = strchr(group, '/') + 1;
 624                         event[-1] = '\0';
 625                         if (strlen(group) == 0) {
 626                                 pr_info("Group name is not specified\n");
 627                                 return -EINVAL;
 628                         }
 629                 }
 630                 if (strlen(event) == 0) {
 631                         pr_info("Event name is not specified\n");
 632                         return -EINVAL;
 633                 }
 634         }
 635         if (!group)
 636                 group = KPROBE_EVENT_SYSTEM;
 637
 638         if (is_delete) {
 639                 if (!event) {
 640                         pr_info("Delete command needs an event name.\n");
 641                         return -EINVAL;
 642                 }
 643                 mutex_lock(&probe_lock);
 644                 tk = find_trace_kprobe(event, group);
 645                 if (!tk) {
 646                         mutex_unlock(&probe_lock);
 647                         pr_info("Event %s/%s doesn't exist.\n", group, event);
 648                         return -ENOENT;
 649                 }
 650                 /* delete an event */
 651                 ret = unregister_trace_kprobe(tk);
 652                 if (ret == 0)
 653                         free_trace_kprobe(tk);
 654                 mutex_unlock(&probe_lock);
 655                 return ret;
 656         }
 657
 658         if (argc < 2) {
 659                 pr_info("Probe point is not specified.\n");
 660                 return -EINVAL;
 661         }
 662         if (isdigit(argv[1][0])) {
 663                 if (is_return) {
 664                         pr_info("Return probe point must be a symbol.\n");
 665                         return -EINVAL;
 666                 }
 667                 /* an address specified */
 668                 ret = kstrtoul(&argv[1][0], 0, (unsigned long *)&addr);
 669                 if (ret) {
 670                         pr_info("Failed to parse address.\n");
 671                         return ret;
 672                 }
 673         } else {
 674                 /* a symbol specified */
 675                 symbol = argv[1];
 676                 /* TODO: support .init module functions */
 677                 ret = traceprobe_split_symbol_offset(symbol, &offset);
 678                 if (ret) {
 679                         pr_info("Failed to parse symbol.\n");
 680                         return ret;
 681                 }
 682                 if (offset && is_return) {
 683                         pr_info("Return probe must be used without offset.\n");
 684                         return -EINVAL;
 685                 }
 686         }
 687         argc -= 2; argv += 2;
 688
 689         /* setup a probe */
 690         if (!event) {
 691                 /* Make a new event name */
 692                 if (symbol)
 693                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 694                                  is_return ? 'r' : 'p', symbol, offset);
 695                 else
 696                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 697                                  is_return ? 'r' : 'p', addr);
 698                 event = buf;
 699         }
 700         tk = alloc_trace_kprobe(group, event, addr, symbol, offset, argc,
 701                                is_return);
 702         if (IS_ERR(tk)) {
 703                 pr_info("Failed to allocate trace_probe.(%d)\n",
 704                         (int)PTR_ERR(tk));
 705                 return PTR_ERR(tk);
 706         }
 707
 708         /* parse arguments */
 709         ret = 0;
 710         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 711                 struct probe_arg *parg = &tk->tp.args[i];
 712
 713                 /* Increment count for freeing args in error case */
 714                 tk->tp.nr_args++;
 715
 716                 /* Parse argument name */
 717                 arg = strchr(argv[i], '=');
 718                 if (arg) {
 719                         *arg++ = '\0';
 720                         parg->name = kstrdup(argv[i], GFP_KERNEL);
 721                 } else {
 722                         arg = argv[i];
 723                         /* If argument name is omitted, set "argN" */
 724                         snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
 725                         parg->name = kstrdup(buf, GFP_KERNEL);
 726                 }
 727
 728                 if (!parg->name) {
 729                         pr_info("Failed to allocate argument[%d] name.\n", i);
 730                         ret = -ENOMEM;
 731                         goto error;
 732                 }
 733
 734                 if (!is_good_name(parg->name)) {
 735                         pr_info("Invalid argument[%d] name: %s\n",
 736                                 i, parg->name);
 737                         ret = -EINVAL;
 738                         goto error;
 739                 }
 740
 741                 if (traceprobe_conflict_field_name(parg->name,
 742                                                         tk->tp.args, i)) {
 743                         pr_info("Argument[%d] name '%s' conflicts with "
 744                                 "another field.\n", i, argv[i]);
 745                         ret = -EINVAL;
 746                         goto error;
 747                 }
 748
 749                 /* Parse fetch argument */
 750                 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
 751                                                 is_return, true,
 752                                                 kprobes_fetch_type_table);
 753                 if (ret) {
 754                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
 755                         goto error;
 756                 }
 757         }
 758
 759         ret = register_trace_kprobe(tk);
 760         if (ret)
 761                 goto error;
 762         return 0;
 763
 764 error:
 765         free_trace_kprobe(tk);
 766         return ret;
 767 }
 768
 769 static int release_all_trace_kprobes(void)
 770 {
 771         struct trace_kprobe *tk;
 772         int ret = 0;
 773
 774         mutex_lock(&probe_lock);
 775         /* Ensure no probe is in use. */
 776         list_for_each_entry(tk, &probe_list, list)
 777                 if (trace_probe_is_enabled(&tk->tp)) {
 778                         ret = -EBUSY;
 779                         goto end;
 780                 }
 781         /* TODO: Use batch unregistration */
 782         while (!list_empty(&probe_list)) {
 783                 tk = list_entry(probe_list.next, struct trace_kprobe, list);
 784                 ret = unregister_trace_kprobe(tk);
 785                 if (ret)
 786                         goto end;
 787                 free_trace_kprobe(tk);
 788         }
 789
 790 end:
 791         mutex_unlock(&probe_lock);
 792
 793         return ret;
 794 }
 795
 796 /* Probes listing interfaces */
 797 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
 798 {
 799         mutex_lock(&probe_lock);
 800         return seq_list_start(&probe_list, *pos);
 801 }
 802
 803 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
 804 {
 805         return seq_list_next(v, &probe_list, pos);
 806 }
 807
 808 static void probes_seq_stop(struct seq_file *m, void *v)
 809 {
 810         mutex_unlock(&probe_lock);
 811 }
 812
 813 static int probes_seq_show(struct seq_file *m, void *v)
 814 {
 815         struct trace_kprobe *tk = v;
 816         int i;
 817
 818         seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
 819         seq_printf(m, ":%s/%s", tk->tp.call.class->system,
 820                         trace_event_name(&tk->tp.call));
 821
 822         if (!tk->symbol)
 823                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
 824         else if (tk->rp.kp.offset)
 825                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
 826                            tk->rp.kp.offset);
 827         else
 828                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
 829
 830         for (i = 0; i < tk->tp.nr_args; i++)
 831                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
 832         seq_putc(m, '\n');
 833
 834         return 0;
 835 }
 836
 837 static const struct seq_operations probes_seq_op = {
 838         .start  = probes_seq_start,
 839         .next   = probes_seq_next,
 840         .stop   = probes_seq_stop,
 841         .show   = probes_seq_show
 842 };
 843
 844 static int probes_open(struct inode *inode, struct file *file)
 845 {
 846         int ret;
 847
 848         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
 849                 ret = release_all_trace_kprobes();
 850                 if (ret < 0)
 851                         return ret;
 852         }
 853
 854         return seq_open(file, &probes_seq_op);
 855 }
 856
 857 static ssize_t probes_write(struct file *file, const char __user *buffer,
 858                             size_t count, loff_t *ppos)
 859 {
 860         return traceprobe_probes_write(file, buffer, count, ppos,
 861                         create_trace_kprobe);
 862 }
 863
 864 static const struct file_operations kprobe_events_ops = {
 865         .owner          = THIS_MODULE,
 866         .open           = probes_open,
 867         .read           = seq_read,
 868         .llseek         = seq_lseek,
 869         .release        = seq_release,
 870         .write          = probes_write,
 871 };
 872
 873 /* Probes profiling interfaces */
 874 static int probes_profile_seq_show(struct seq_file *m, void *v)
 875 {
 876         struct trace_kprobe *tk = v;
 877
 878         seq_printf(m, "  %-44s %15lu %15lu\n",
 879                    trace_event_name(&tk->tp.call), 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 nokprobe_inline void
 907 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
 908                     struct trace_event_file *trace_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 trace_event_call *call = &tk->tp.call;
 916
 917         WARN_ON(call != trace_file->event_call);
 918
 919         if (trace_trigger_soft_disabled(trace_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, trace_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(trace_file, buffer, event,
 939                                          entry, irq_flags, pc, regs);
 940 }
 941
 942 static 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 NOKPROBE_SYMBOL(kprobe_trace_func);
 951
 952 /* Kretprobe handler */
 953 static nokprobe_inline void
 954 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
 955                        struct pt_regs *regs,
 956                        struct trace_event_file *trace_file)
 957 {
 958         struct kretprobe_trace_entry_head *entry;
 959         struct ring_buffer_event *event;
 960         struct ring_buffer *buffer;
 961         int size, pc, dsize;
 962         unsigned long irq_flags;
 963         struct trace_event_call *call = &tk->tp.call;
 964
 965         WARN_ON(call != trace_file->event_call);
 966
 967         if (trace_trigger_soft_disabled(trace_file))
 968                 return;
 969
 970         local_save_flags(irq_flags);
 971         pc = preempt_count();
 972
 973         dsize = __get_data_size(&tk->tp, regs);
 974         size = sizeof(*entry) + tk->tp.size + dsize;
 975
 976         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
 977                                                 call->event.type,
 978                                                 size, irq_flags, pc);
 979         if (!event)
 980                 return;
 981
 982         entry = ring_buffer_event_data(event);
 983         entry->func = (unsigned long)tk->rp.kp.addr;
 984         entry->ret_ip = (unsigned long)ri->ret_addr;
 985         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
 986
 987         event_trigger_unlock_commit_regs(trace_file, buffer, event,
 988                                          entry, irq_flags, pc, regs);
 989 }
 990
 991 static void
 992 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
 993                      struct pt_regs *regs)
 994 {
 995         struct event_file_link *link;
 996
 997         list_for_each_entry_rcu(link, &tk->tp.files, list)
 998                 __kretprobe_trace_func(tk, ri, regs, link->file);
 999 }
1000 NOKPROBE_SYMBOL(kretprobe_trace_func);
1001
1002 /* Event entry printers */
1003 static enum print_line_t
1004 print_kprobe_event(struct trace_iterator *iter, int flags,
1005                    struct trace_event *event)
1006 {
1007         struct kprobe_trace_entry_head *field;
1008         struct trace_seq *s = &iter->seq;
1009         struct trace_probe *tp;
1010         u8 *data;
1011         int i;
1012
1013         field = (struct kprobe_trace_entry_head *)iter->ent;
1014         tp = container_of(event, struct trace_probe, call.event);
1015
1016         trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1017
1018         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1019                 goto out;
1020
1021         trace_seq_putc(s, ')');
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 out;
1028
1029         trace_seq_putc(s, '\n');
1030  out:
1031         return trace_handle_return(s);
1032 }
1033
1034 static enum print_line_t
1035 print_kretprobe_event(struct trace_iterator *iter, int flags,
1036                       struct trace_event *event)
1037 {
1038         struct kretprobe_trace_entry_head *field;
1039         struct trace_seq *s = &iter->seq;
1040         struct trace_probe *tp;
1041         u8 *data;
1042         int i;
1043
1044         field = (struct kretprobe_trace_entry_head *)iter->ent;
1045         tp = container_of(event, struct trace_probe, call.event);
1046
1047         trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1048
1049         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1050                 goto out;
1051
1052         trace_seq_puts(s, " <- ");
1053
1054         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1055                 goto out;
1056
1057         trace_seq_putc(s, ')');
1058
1059         data = (u8 *)&field[1];
1060         for (i = 0; i < tp->nr_args; i++)
1061                 if (!tp->args[i].type->print(s, tp->args[i].name,
1062                                              data + tp->args[i].offset, field))
1063                         goto out;
1064
1065         trace_seq_putc(s, '\n');
1066
1067  out:
1068         return trace_handle_return(s);
1069 }
1070
1071
1072 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1073 {
1074         int ret, i;
1075         struct kprobe_trace_entry_head field;
1076         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1077
1078         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1079         /* Set argument names as fields */
1080         for (i = 0; i < tk->tp.nr_args; i++) {
1081                 struct probe_arg *parg = &tk->tp.args[i];
1082
1083                 ret = trace_define_field(event_call, parg->type->fmttype,
1084                                          parg->name,
1085                                          sizeof(field) + parg->offset,
1086                                          parg->type->size,
1087                                          parg->type->is_signed,
1088                                          FILTER_OTHER);
1089                 if (ret)
1090                         return ret;
1091         }
1092         return 0;
1093 }
1094
1095 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1096 {
1097         int ret, i;
1098         struct kretprobe_trace_entry_head field;
1099         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1100
1101         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1102         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1103         /* Set argument names as fields */
1104         for (i = 0; i < tk->tp.nr_args; i++) {
1105                 struct probe_arg *parg = &tk->tp.args[i];
1106
1107                 ret = trace_define_field(event_call, parg->type->fmttype,
1108                                          parg->name,
1109                                          sizeof(field) + parg->offset,
1110                                          parg->type->size,
1111                                          parg->type->is_signed,
1112                                          FILTER_OTHER);
1113                 if (ret)
1114                         return ret;
1115         }
1116         return 0;
1117 }
1118
1119 #ifdef CONFIG_PERF_EVENTS
1120
1121 /* Kprobe profile handler */
1122 static void
1123 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1124 {
1125         struct trace_event_call *call = &tk->tp.call;
1126         struct bpf_prog *prog = call->prog;
1127         struct kprobe_trace_entry_head *entry;
1128         struct hlist_head *head;
1129         int size, __size, dsize;
1130         int rctx;
1131
1132         if (prog && !trace_call_bpf(prog, regs))
1133                 return;
1134
1135         head = this_cpu_ptr(call->perf_events);
1136         if (hlist_empty(head))
1137                 return;
1138
1139         dsize = __get_data_size(&tk->tp, regs);
1140         __size = sizeof(*entry) + tk->tp.size + dsize;
1141         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1142         size -= sizeof(u32);
1143
1144         entry = perf_trace_buf_prepare(size, call->event.type, NULL, &rctx);
1145         if (!entry)
1146                 return;
1147
1148         entry->ip = (unsigned long)tk->rp.kp.addr;
1149         memset(&entry[1], 0, dsize);
1150         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1151         perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1152 }
1153 NOKPROBE_SYMBOL(kprobe_perf_func);
1154
1155 /* Kretprobe profile handler */
1156 static void
1157 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1158                     struct pt_regs *regs)
1159 {
1160         struct trace_event_call *call = &tk->tp.call;
1161         struct bpf_prog *prog = call->prog;
1162         struct kretprobe_trace_entry_head *entry;
1163         struct hlist_head *head;
1164         int size, __size, dsize;
1165         int rctx;
1166
1167         if (prog && !trace_call_bpf(prog, regs))
1168                 return;
1169
1170         head = this_cpu_ptr(call->perf_events);
1171         if (hlist_empty(head))
1172                 return;
1173
1174         dsize = __get_data_size(&tk->tp, regs);
1175         __size = sizeof(*entry) + tk->tp.size + dsize;
1176         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1177         size -= sizeof(u32);
1178
1179         entry = perf_trace_buf_prepare(size, call->event.type, NULL, &rctx);
1180         if (!entry)
1181                 return;
1182
1183         entry->func = (unsigned long)tk->rp.kp.addr;
1184         entry->ret_ip = (unsigned long)ri->ret_addr;
1185         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1186         perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1187 }
1188 NOKPROBE_SYMBOL(kretprobe_perf_func);
1189 #endif  /* CONFIG_PERF_EVENTS */
1190
1191 /*
1192  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1193  *
1194  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1195  * lockless, but we can't race with this __init function.
1196  */
1197 static int kprobe_register(struct trace_event_call *event,
1198                            enum trace_reg type, void *data)
1199 {
1200         struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1201         struct trace_event_file *file = data;
1202
1203         switch (type) {
1204         case TRACE_REG_REGISTER:
1205                 return enable_trace_kprobe(tk, file);
1206         case TRACE_REG_UNREGISTER:
1207                 return disable_trace_kprobe(tk, file);
1208
1209 #ifdef CONFIG_PERF_EVENTS
1210         case TRACE_REG_PERF_REGISTER:
1211                 return enable_trace_kprobe(tk, NULL);
1212         case TRACE_REG_PERF_UNREGISTER:
1213                 return disable_trace_kprobe(tk, NULL);
1214         case TRACE_REG_PERF_OPEN:
1215         case TRACE_REG_PERF_CLOSE:
1216         case TRACE_REG_PERF_ADD:
1217         case TRACE_REG_PERF_DEL:
1218                 return 0;
1219 #endif
1220         }
1221         return 0;
1222 }
1223
1224 static 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 NOKPROBE_SYMBOL(kprobe_dispatcher);
1239
1240 static int
1241 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1242 {
1243         struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1244
1245         tk->nhit++;
1246
1247         if (tk->tp.flags & TP_FLAG_TRACE)
1248                 kretprobe_trace_func(tk, ri, regs);
1249 #ifdef CONFIG_PERF_EVENTS
1250         if (tk->tp.flags & TP_FLAG_PROFILE)
1251                 kretprobe_perf_func(tk, ri, regs);
1252 #endif
1253         return 0;       /* We don't tweek kernel, so just return 0 */
1254 }
1255 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1256
1257 static struct trace_event_functions kretprobe_funcs = {
1258         .trace          = print_kretprobe_event
1259 };
1260
1261 static struct trace_event_functions kprobe_funcs = {
1262         .trace          = print_kprobe_event
1263 };
1264
1265 static int register_kprobe_event(struct trace_kprobe *tk)
1266 {
1267         struct trace_event_call *call = &tk->tp.call;
1268         int ret;
1269
1270         /* Initialize trace_event_call */
1271         INIT_LIST_HEAD(&call->class->fields);
1272         if (trace_kprobe_is_return(tk)) {
1273                 call->event.funcs = &kretprobe_funcs;
1274                 call->class->define_fields = kretprobe_event_define_fields;
1275         } else {
1276                 call->event.funcs = &kprobe_funcs;
1277                 call->class->define_fields = kprobe_event_define_fields;
1278         }
1279         if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1280                 return -ENOMEM;
1281         ret = register_trace_event(&call->event);
1282         if (!ret) {
1283                 kfree(call->print_fmt);
1284                 return -ENODEV;
1285         }
1286         call->flags = TRACE_EVENT_FL_KPROBE;
1287         call->class->reg = kprobe_register;
1288         call->data = tk;
1289         ret = trace_add_event_call(call);
1290         if (ret) {
1291                 pr_info("Failed to register kprobe event: %s\n",
1292                         trace_event_name(call));
1293                 kfree(call->print_fmt);
1294                 unregister_trace_event(&call->event);
1295         }
1296         return ret;
1297 }
1298
1299 static int unregister_kprobe_event(struct trace_kprobe *tk)
1300 {
1301         int ret;
1302
1303         /* tp->event is unregistered in trace_remove_event_call() */
1304         ret = trace_remove_event_call(&tk->tp.call);
1305         if (!ret)
1306                 kfree(tk->tp.call.print_fmt);
1307         return ret;
1308 }
1309
1310 /* Make a tracefs interface for controlling probe points */
1311 static __init int init_kprobe_trace(void)
1312 {
1313         struct dentry *d_tracer;
1314         struct dentry *entry;
1315
1316         if (register_module_notifier(&trace_kprobe_module_nb))
1317                 return -EINVAL;
1318
1319         d_tracer = tracing_init_dentry();
1320         if (IS_ERR(d_tracer))
1321                 return 0;
1322
1323         entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1324                                     NULL, &kprobe_events_ops);
1325
1326         /* Event list interface */
1327         if (!entry)
1328                 pr_warning("Could not create tracefs "
1329                            "'kprobe_events' entry\n");
1330
1331         /* Profile interface */
1332         entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1333                                     NULL, &kprobe_profile_ops);
1334
1335         if (!entry)
1336                 pr_warning("Could not create tracefs "
1337                            "'kprobe_profile' entry\n");
1338         return 0;
1339 }
1340 fs_initcall(init_kprobe_trace);
1341
1342
1343 #ifdef CONFIG_FTRACE_STARTUP_TEST
1344
1345 /*
1346  * The "__used" keeps gcc from removing the function symbol
1347  * from the kallsyms table.
1348  */
1349 static __used int kprobe_trace_selftest_target(int a1, int a2, int a3,
1350                                                int a4, int a5, int a6)
1351 {
1352         return a1 + a2 + a3 + a4 + a5 + a6;
1353 }
1354
1355 static struct trace_event_file *
1356 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1357 {
1358         struct trace_event_file *file;
1359
1360         list_for_each_entry(file, &tr->events, list)
1361                 if (file->event_call == &tk->tp.call)
1362                         return file;
1363
1364         return NULL;
1365 }
1366
1367 /*
1368  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1369  * stage, we can do this lockless.
1370  */
1371 static __init int kprobe_trace_self_tests_init(void)
1372 {
1373         int ret, warn = 0;
1374         int (*target)(int, int, int, int, int, int);
1375         struct trace_kprobe *tk;
1376         struct trace_event_file *file;
1377
1378         if (tracing_is_disabled())
1379                 return -ENODEV;
1380
1381         target = kprobe_trace_selftest_target;
1382
1383         pr_info("Testing kprobe tracing: ");
1384
1385         ret = traceprobe_command("p:testprobe kprobe_trace_selftest_target "
1386                                   "$stack $stack0 +0($stack)",
1387                                   create_trace_kprobe);
1388         if (WARN_ON_ONCE(ret)) {
1389                 pr_warn("error on probing function entry.\n");
1390                 warn++;
1391         } else {
1392                 /* Enable trace point */
1393                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1394                 if (WARN_ON_ONCE(tk == NULL)) {
1395                         pr_warn("error on getting new probe.\n");
1396                         warn++;
1397                 } else {
1398                         file = find_trace_probe_file(tk, top_trace_array());
1399                         if (WARN_ON_ONCE(file == NULL)) {
1400                                 pr_warn("error on getting probe file.\n");
1401                                 warn++;
1402                         } else
1403                                 enable_trace_kprobe(tk, file);
1404                 }
1405         }
1406
1407         ret = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target "
1408                                   "$retval", create_trace_kprobe);
1409         if (WARN_ON_ONCE(ret)) {
1410                 pr_warn("error on probing function return.\n");
1411                 warn++;
1412         } else {
1413                 /* Enable trace point */
1414                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1415                 if (WARN_ON_ONCE(tk == NULL)) {
1416                         pr_warn("error on getting 2nd 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         if (warn)
1429                 goto end;
1430
1431         ret = target(1, 2, 3, 4, 5, 6);
1432
1433         /* Disable trace points before removing it */
1434         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1435         if (WARN_ON_ONCE(tk == NULL)) {
1436                 pr_warn("error on getting test probe.\n");
1437                 warn++;
1438         } else {
1439                 file = find_trace_probe_file(tk, top_trace_array());
1440                 if (WARN_ON_ONCE(file == NULL)) {
1441                         pr_warn("error on getting probe file.\n");
1442                         warn++;
1443                 } else
1444                         disable_trace_kprobe(tk, file);
1445         }
1446
1447         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1448         if (WARN_ON_ONCE(tk == NULL)) {
1449                 pr_warn("error on getting 2nd test probe.\n");
1450                 warn++;
1451         } else {
1452                 file = find_trace_probe_file(tk, top_trace_array());
1453                 if (WARN_ON_ONCE(file == NULL)) {
1454                         pr_warn("error on getting probe file.\n");
1455                         warn++;
1456                 } else
1457                         disable_trace_kprobe(tk, file);
1458         }
1459
1460         ret = traceprobe_command("-:testprobe", create_trace_kprobe);
1461         if (WARN_ON_ONCE(ret)) {
1462                 pr_warn("error on deleting a probe.\n");
1463                 warn++;
1464         }
1465
1466         ret = traceprobe_command("-:testprobe2", create_trace_kprobe);
1467         if (WARN_ON_ONCE(ret)) {
1468                 pr_warn("error on deleting a probe.\n");
1469                 warn++;
1470         }
1471
1472 end:
1473         release_all_trace_kprobes();
1474         if (warn)
1475                 pr_cont("NG: Some tests are failed. Please check them.\n");
1476         else
1477                 pr_cont("OK\n");
1478         return 0;
1479 }
1480
1481 late_initcall(kprobe_trace_self_tests_init);
1482
1483 #endif