kernel/trace/trace_kprobe.c

   1 /*
   2  * kprobe based kernel tracer
   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 #include <linux/kprobes.h>
  23 #include <linux/seq_file.h>
  24 #include <linux/slab.h>
  25 #include <linux/smp.h>
  26 #include <linux/debugfs.h>
  27 #include <linux/types.h>
  28 #include <linux/string.h>
  29 #include <linux/ctype.h>
  30 #include <linux/ptrace.h>
  31 #include <linux/perf_event.h>
  32
  33 #include "trace.h"
  34 #include "trace_output.h"
  35
  36 #define MAX_TRACE_ARGS 128
  37 #define MAX_ARGSTR_LEN 63
  38 #define MAX_EVENT_NAME_LEN 64
  39 #define KPROBE_EVENT_SYSTEM "kprobes"
  40
  41 /* currently, trace_kprobe only supports X86. */
  42
  43 struct fetch_func {
  44         unsigned long (*func)(struct pt_regs *, void *);
  45         void *data;
  46 };
  47
  48 static __kprobes unsigned long call_fetch(struct fetch_func *f,
  49                                           struct pt_regs *regs)
  50 {
  51         return f->func(regs, f->data);
  52 }
  53
  54 /* fetch handlers */
  55 static __kprobes unsigned long fetch_register(struct pt_regs *regs,
  56                                               void *offset)
  57 {
  58         return regs_get_register(regs, (unsigned int)((unsigned long)offset));
  59 }
  60
  61 static __kprobes unsigned long fetch_stack(struct pt_regs *regs,
  62                                            void *num)
  63 {
  64         return regs_get_kernel_stack_nth(regs,
  65                                          (unsigned int)((unsigned long)num));
  66 }
  67
  68 static __kprobes unsigned long fetch_memory(struct pt_regs *regs, void *addr)
  69 {
  70         unsigned long retval;
  71
  72         if (probe_kernel_address(addr, retval))
  73                 return 0;
  74         return retval;
  75 }
  76
  77 static __kprobes unsigned long fetch_argument(struct pt_regs *regs, void *num)
  78 {
  79         return regs_get_argument_nth(regs, (unsigned int)((unsigned long)num));
  80 }
  81
  82 static __kprobes unsigned long fetch_retvalue(struct pt_regs *regs,
  83                                               void *dummy)
  84 {
  85         return regs_return_value(regs);
  86 }
  87
  88 static __kprobes unsigned long fetch_stack_address(struct pt_regs *regs,
  89                                                    void *dummy)
  90 {
  91         return kernel_stack_pointer(regs);
  92 }
  93
  94 /* Memory fetching by symbol */
  95 struct symbol_cache {
  96         char *symbol;
  97         long offset;
  98         unsigned long addr;
  99 };
 100
 101 static unsigned long update_symbol_cache(struct symbol_cache *sc)
 102 {
 103         sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
 104         if (sc->addr)
 105                 sc->addr += sc->offset;
 106         return sc->addr;
 107 }
 108
 109 static void free_symbol_cache(struct symbol_cache *sc)
 110 {
 111         kfree(sc->symbol);
 112         kfree(sc);
 113 }
 114
 115 static struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
 116 {
 117         struct symbol_cache *sc;
 118
 119         if (!sym || strlen(sym) == 0)
 120                 return NULL;
 121         sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
 122         if (!sc)
 123                 return NULL;
 124
 125         sc->symbol = kstrdup(sym, GFP_KERNEL);
 126         if (!sc->symbol) {
 127                 kfree(sc);
 128                 return NULL;
 129         }
 130         sc->offset = offset;
 131
 132         update_symbol_cache(sc);
 133         return sc;
 134 }
 135
 136 static __kprobes unsigned long fetch_symbol(struct pt_regs *regs, void *data)
 137 {
 138         struct symbol_cache *sc = data;
 139
 140         if (sc->addr)
 141                 return fetch_memory(regs, (void *)sc->addr);
 142         else
 143                 return 0;
 144 }
 145
 146 /* Special indirect memory access interface */
 147 struct indirect_fetch_data {
 148         struct fetch_func orig;
 149         long offset;
 150 };
 151
 152 static __kprobes unsigned long fetch_indirect(struct pt_regs *regs, void *data)
 153 {
 154         struct indirect_fetch_data *ind = data;
 155         unsigned long addr;
 156
 157         addr = call_fetch(&ind->orig, regs);
 158         if (addr) {
 159                 addr += ind->offset;
 160                 return fetch_memory(regs, (void *)addr);
 161         } else
 162                 return 0;
 163 }
 164
 165 static __kprobes void free_indirect_fetch_data(struct indirect_fetch_data *data)
 166 {
 167         if (data->orig.func == fetch_indirect)
 168                 free_indirect_fetch_data(data->orig.data);
 169         else if (data->orig.func == fetch_symbol)
 170                 free_symbol_cache(data->orig.data);
 171         kfree(data);
 172 }
 173
 174 /**
 175  * Kprobe tracer core functions
 176  */
 177
 178 struct probe_arg {
 179         struct fetch_func       fetch;
 180         const char              *name;
 181 };
 182
 183 /* Flags for trace_probe */
 184 #define TP_FLAG_TRACE   1
 185 #define TP_FLAG_PROFILE 2
 186
 187 struct trace_probe {
 188         struct list_head        list;
 189         struct kretprobe        rp;     /* Use rp.kp for kprobe use */
 190         unsigned long           nhit;
 191         unsigned int            flags;  /* For TP_FLAG_* */
 192         const char              *symbol;        /* symbol name */
 193         struct ftrace_event_call        call;
 194         struct trace_event              event;
 195         unsigned int            nr_args;
 196         struct probe_arg        args[];
 197 };
 198
 199 #define SIZEOF_TRACE_PROBE(n)                   \
 200         (offsetof(struct trace_probe, args) +   \
 201         (sizeof(struct probe_arg) * (n)))
 202
 203 static __kprobes int probe_is_return(struct trace_probe *tp)
 204 {
 205         return tp->rp.handler != NULL;
 206 }
 207
 208 static __kprobes const char *probe_symbol(struct trace_probe *tp)
 209 {
 210         return tp->symbol ? tp->symbol : "unknown";
 211 }
 212
 213 static int probe_arg_string(char *buf, size_t n, struct fetch_func *ff)
 214 {
 215         int ret = -EINVAL;
 216
 217         if (ff->func == fetch_argument)
 218                 ret = snprintf(buf, n, "$a%lu", (unsigned long)ff->data);
 219         else if (ff->func == fetch_register) {
 220                 const char *name;
 221                 name = regs_query_register_name((unsigned int)((long)ff->data));
 222                 ret = snprintf(buf, n, "%%%s", name);
 223         } else if (ff->func == fetch_stack)
 224                 ret = snprintf(buf, n, "$s%lu", (unsigned long)ff->data);
 225         else if (ff->func == fetch_memory)
 226                 ret = snprintf(buf, n, "@0x%p", ff->data);
 227         else if (ff->func == fetch_symbol) {
 228                 struct symbol_cache *sc = ff->data;
 229                 ret = snprintf(buf, n, "@%s%+ld", sc->symbol, sc->offset);
 230         } else if (ff->func == fetch_retvalue)
 231                 ret = snprintf(buf, n, "$rv");
 232         else if (ff->func == fetch_stack_address)
 233                 ret = snprintf(buf, n, "$sa");
 234         else if (ff->func == fetch_indirect) {
 235                 struct indirect_fetch_data *id = ff->data;
 236                 size_t l = 0;
 237                 ret = snprintf(buf, n, "%+ld(", id->offset);
 238                 if (ret >= n)
 239                         goto end;
 240                 l += ret;
 241                 ret = probe_arg_string(buf + l, n - l, &id->orig);
 242                 if (ret < 0)
 243                         goto end;
 244                 l += ret;
 245                 ret = snprintf(buf + l, n - l, ")");
 246                 ret += l;
 247         }
 248 end:
 249         if (ret >= n)
 250                 return -ENOSPC;
 251         return ret;
 252 }
 253
 254 static int register_probe_event(struct trace_probe *tp);
 255 static void unregister_probe_event(struct trace_probe *tp);
 256
 257 static DEFINE_MUTEX(probe_lock);
 258 static LIST_HEAD(probe_list);
 259
 260 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
 261 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
 262                                 struct pt_regs *regs);
 263
 264 /*
 265  * Allocate new trace_probe and initialize it (including kprobes).
 266  */
 267 static struct trace_probe *alloc_trace_probe(const char *group,
 268                                              const char *event,
 269                                              void *addr,
 270                                              const char *symbol,
 271                                              unsigned long offs,
 272                                              int nargs, int is_return)
 273 {
 274         struct trace_probe *tp;
 275
 276         tp = kzalloc(SIZEOF_TRACE_PROBE(nargs), GFP_KERNEL);
 277         if (!tp)
 278                 return ERR_PTR(-ENOMEM);
 279
 280         if (symbol) {
 281                 tp->symbol = kstrdup(symbol, GFP_KERNEL);
 282                 if (!tp->symbol)
 283                         goto error;
 284                 tp->rp.kp.symbol_name = tp->symbol;
 285                 tp->rp.kp.offset = offs;
 286         } else
 287                 tp->rp.kp.addr = addr;
 288
 289         if (is_return)
 290                 tp->rp.handler = kretprobe_dispatcher;
 291         else
 292                 tp->rp.kp.pre_handler = kprobe_dispatcher;
 293
 294         if (!event)
 295                 goto error;
 296         tp->call.name = kstrdup(event, GFP_KERNEL);
 297         if (!tp->call.name)
 298                 goto error;
 299
 300         if (!group)
 301                 goto error;
 302         tp->call.system = kstrdup(group, GFP_KERNEL);
 303         if (!tp->call.system)
 304                 goto error;
 305
 306         INIT_LIST_HEAD(&tp->list);
 307         return tp;
 308 error:
 309         kfree(tp->call.name);
 310         kfree(tp->symbol);
 311         kfree(tp);
 312         return ERR_PTR(-ENOMEM);
 313 }
 314
 315 static void free_probe_arg(struct probe_arg *arg)
 316 {
 317         if (arg->fetch.func == fetch_symbol)
 318                 free_symbol_cache(arg->fetch.data);
 319         else if (arg->fetch.func == fetch_indirect)
 320                 free_indirect_fetch_data(arg->fetch.data);
 321         kfree(arg->name);
 322 }
 323
 324 static void free_trace_probe(struct trace_probe *tp)
 325 {
 326         int i;
 327
 328         for (i = 0; i < tp->nr_args; i++)
 329                 free_probe_arg(&tp->args[i]);
 330
 331         kfree(tp->call.system);
 332         kfree(tp->call.name);
 333         kfree(tp->symbol);
 334         kfree(tp);
 335 }
 336
 337 static struct trace_probe *find_probe_event(const char *event)
 338 {
 339         struct trace_probe *tp;
 340
 341         list_for_each_entry(tp, &probe_list, list)
 342                 if (!strcmp(tp->call.name, event))
 343                         return tp;
 344         return NULL;
 345 }
 346
 347 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
 348 static void unregister_trace_probe(struct trace_probe *tp)
 349 {
 350         if (probe_is_return(tp))
 351                 unregister_kretprobe(&tp->rp);
 352         else
 353                 unregister_kprobe(&tp->rp.kp);
 354         list_del(&tp->list);
 355         unregister_probe_event(tp);
 356 }
 357
 358 /* Register a trace_probe and probe_event */
 359 static int register_trace_probe(struct trace_probe *tp)
 360 {
 361         struct trace_probe *old_tp;
 362         int ret;
 363
 364         mutex_lock(&probe_lock);
 365
 366         /* register as an event */
 367         old_tp = find_probe_event(tp->call.name);
 368         if (old_tp) {
 369                 /* delete old event */
 370                 unregister_trace_probe(old_tp);
 371                 free_trace_probe(old_tp);
 372         }
 373         ret = register_probe_event(tp);
 374         if (ret) {
 375                 pr_warning("Faild to register probe event(%d)\n", ret);
 376                 goto end;
 377         }
 378
 379         tp->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 380         if (probe_is_return(tp))
 381                 ret = register_kretprobe(&tp->rp);
 382         else
 383                 ret = register_kprobe(&tp->rp.kp);
 384
 385         if (ret) {
 386                 pr_warning("Could not insert probe(%d)\n", ret);
 387                 if (ret == -EILSEQ) {
 388                         pr_warning("Probing address(0x%p) is not an "
 389                                    "instruction boundary.\n",
 390                                    tp->rp.kp.addr);
 391                         ret = -EINVAL;
 392                 }
 393                 unregister_probe_event(tp);
 394         } else
 395                 list_add_tail(&tp->list, &probe_list);
 396 end:
 397         mutex_unlock(&probe_lock);
 398         return ret;
 399 }
 400
 401 /* Split symbol and offset. */
 402 static int split_symbol_offset(char *symbol, unsigned long *offset)
 403 {
 404         char *tmp;
 405         int ret;
 406
 407         if (!offset)
 408                 return -EINVAL;
 409
 410         tmp = strchr(symbol, '+');
 411         if (tmp) {
 412                 /* skip sign because strict_strtol doesn't accept '+' */
 413                 ret = strict_strtoul(tmp + 1, 0, offset);
 414                 if (ret)
 415                         return ret;
 416                 *tmp = '\0';
 417         } else
 418                 *offset = 0;
 419         return 0;
 420 }
 421
 422 #define PARAM_MAX_ARGS 16
 423 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
 424
 425 static int parse_probe_vars(char *arg, struct fetch_func *ff, int is_return)
 426 {
 427         int ret = 0;
 428         unsigned long param;
 429
 430         switch (arg[0]) {
 431         case 'a':       /* argument */
 432                 ret = strict_strtoul(arg + 1, 10, &param);
 433                 if (ret || param > PARAM_MAX_ARGS)
 434                         ret = -EINVAL;
 435                 else {
 436                         ff->func = fetch_argument;
 437                         ff->data = (void *)param;
 438                 }
 439                 break;
 440         case 'r':       /* retval or retaddr */
 441                 if (is_return && arg[1] == 'v') {
 442                         ff->func = fetch_retvalue;
 443                         ff->data = NULL;
 444                 } else
 445                         ret = -EINVAL;
 446                 break;
 447         case 's':       /* stack */
 448                 if (arg[1] == 'a') {
 449                         ff->func = fetch_stack_address;
 450                         ff->data = NULL;
 451                 } else {
 452                         ret = strict_strtoul(arg + 1, 10, &param);
 453                         if (ret || param > PARAM_MAX_STACK)
 454                                 ret = -EINVAL;
 455                         else {
 456                                 ff->func = fetch_stack;
 457                                 ff->data = (void *)param;
 458                         }
 459                 }
 460                 break;
 461         default:
 462                 ret = -EINVAL;
 463         }
 464         return ret;
 465 }
 466
 467 static int parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
 468 {
 469         int ret = 0;
 470         unsigned long param;
 471         long offset;
 472         char *tmp;
 473
 474         switch (arg[0]) {
 475         case '$':
 476                 ret = parse_probe_vars(arg + 1, ff, is_return);
 477                 break;
 478         case '%':       /* named register */
 479                 ret = regs_query_register_offset(arg + 1);
 480                 if (ret >= 0) {
 481                         ff->func = fetch_register;
 482                         ff->data = (void *)(unsigned long)ret;
 483                         ret = 0;
 484                 }
 485                 break;
 486         case '@':       /* memory or symbol */
 487                 if (isdigit(arg[1])) {
 488                         ret = strict_strtoul(arg + 1, 0, &param);
 489                         if (ret)
 490                                 break;
 491                         ff->func = fetch_memory;
 492                         ff->data = (void *)param;
 493                 } else {
 494                         ret = split_symbol_offset(arg + 1, &offset);
 495                         if (ret)
 496                                 break;
 497                         ff->data = alloc_symbol_cache(arg + 1, offset);
 498                         if (ff->data)
 499                                 ff->func = fetch_symbol;
 500                         else
 501                                 ret = -EINVAL;
 502                 }
 503                 break;
 504         case '+':       /* indirect memory */
 505         case '-':
 506                 tmp = strchr(arg, '(');
 507                 if (!tmp) {
 508                         ret = -EINVAL;
 509                         break;
 510                 }
 511                 *tmp = '\0';
 512                 ret = strict_strtol(arg + 1, 0, &offset);
 513                 if (ret)
 514                         break;
 515                 if (arg[0] == '-')
 516                         offset = -offset;
 517                 arg = tmp + 1;
 518                 tmp = strrchr(arg, ')');
 519                 if (tmp) {
 520                         struct indirect_fetch_data *id;
 521                         *tmp = '\0';
 522                         id = kzalloc(sizeof(struct indirect_fetch_data),
 523                                      GFP_KERNEL);
 524                         if (!id)
 525                                 return -ENOMEM;
 526                         id->offset = offset;
 527                         ret = parse_probe_arg(arg, &id->orig, is_return);
 528                         if (ret)
 529                                 kfree(id);
 530                         else {
 531                                 ff->func = fetch_indirect;
 532                                 ff->data = (void *)id;
 533                         }
 534                 } else
 535                         ret = -EINVAL;
 536                 break;
 537         default:
 538                 /* TODO: support custom handler */
 539                 ret = -EINVAL;
 540         }
 541         return ret;
 542 }
 543
 544 static int create_trace_probe(int argc, char **argv)
 545 {
 546         /*
 547          * Argument syntax:
 548          *  - Add kprobe: p[:[GRP/]EVENT] KSYM[+OFFS]|KADDR [FETCHARGS]
 549          *  - Add kretprobe: r[:[GRP/]EVENT] KSYM[+0] [FETCHARGS]
 550          * Fetch args:
 551          *  $aN : fetch Nth of function argument. (N:0-)
 552          *  $rv : fetch return value
 553          *  $sa : fetch stack address
 554          *  $sN : fetch Nth of stack (N:0-)
 555          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 556          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 557          *  %REG        : fetch register REG
 558          * Indirect memory fetch:
 559          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 560          * Alias name of args:
 561          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 562          */
 563         struct trace_probe *tp;
 564         int i, ret = 0;
 565         int is_return = 0;
 566         char *symbol = NULL, *event = NULL, *arg = NULL, *group = NULL;
 567         unsigned long offset = 0;
 568         void *addr = NULL;
 569         char buf[MAX_EVENT_NAME_LEN];
 570
 571         if (argc < 2)
 572                 return -EINVAL;
 573
 574         if (argv[0][0] == 'p')
 575                 is_return = 0;
 576         else if (argv[0][0] == 'r')
 577                 is_return = 1;
 578         else
 579                 return -EINVAL;
 580
 581         if (argv[0][1] == ':') {
 582                 event = &argv[0][2];
 583                 if (strchr(event, '/')) {
 584                         group = event;
 585                         event = strchr(group, '/') + 1;
 586                         event[-1] = '\0';
 587                         if (strlen(group) == 0) {
 588                                 pr_info("Group name is not specifiled\n");
 589                                 return -EINVAL;
 590                         }
 591                 }
 592                 if (strlen(event) == 0) {
 593                         pr_info("Event name is not specifiled\n");
 594                         return -EINVAL;
 595                 }
 596         }
 597
 598         if (isdigit(argv[1][0])) {
 599                 if (is_return)
 600                         return -EINVAL;
 601                 /* an address specified */
 602                 ret = strict_strtoul(&argv[0][2], 0, (unsigned long *)&addr);
 603                 if (ret)
 604                         return ret;
 605         } else {
 606                 /* a symbol specified */
 607                 symbol = argv[1];
 608                 /* TODO: support .init module functions */
 609                 ret = split_symbol_offset(symbol, &offset);
 610                 if (ret)
 611                         return ret;
 612                 if (offset && is_return)
 613                         return -EINVAL;
 614         }
 615         argc -= 2; argv += 2;
 616
 617         /* setup a probe */
 618         if (!group)
 619                 group = KPROBE_EVENT_SYSTEM;
 620         if (!event) {
 621                 /* Make a new event name */
 622                 if (symbol)
 623                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c@%s%+ld",
 624                                  is_return ? 'r' : 'p', symbol, offset);
 625                 else
 626                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c@0x%p",
 627                                  is_return ? 'r' : 'p', addr);
 628                 event = buf;
 629         }
 630         tp = alloc_trace_probe(group, event, addr, symbol, offset, argc,
 631                                is_return);
 632         if (IS_ERR(tp))
 633                 return PTR_ERR(tp);
 634
 635         /* parse arguments */
 636         ret = 0;
 637         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 638                 /* Parse argument name */
 639                 arg = strchr(argv[i], '=');
 640                 if (arg)
 641                         *arg++ = '\0';
 642                 else
 643                         arg = argv[i];
 644                 tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
 645
 646                 /* Parse fetch argument */
 647                 if (strlen(arg) > MAX_ARGSTR_LEN) {
 648                         pr_info("Argument%d(%s) is too long.\n", i, arg);
 649                         ret = -ENOSPC;
 650                         goto error;
 651                 }
 652                 ret = parse_probe_arg(arg, &tp->args[i].fetch, is_return);
 653                 if (ret)
 654                         goto error;
 655         }
 656         tp->nr_args = i;
 657
 658         ret = register_trace_probe(tp);
 659         if (ret)
 660                 goto error;
 661         return 0;
 662
 663 error:
 664         free_trace_probe(tp);
 665         return ret;
 666 }
 667
 668 static void cleanup_all_probes(void)
 669 {
 670         struct trace_probe *tp;
 671
 672         mutex_lock(&probe_lock);
 673         /* TODO: Use batch unregistration */
 674         while (!list_empty(&probe_list)) {
 675                 tp = list_entry(probe_list.next, struct trace_probe, list);
 676                 unregister_trace_probe(tp);
 677                 free_trace_probe(tp);
 678         }
 679         mutex_unlock(&probe_lock);
 680 }
 681
 682
 683 /* Probes listing interfaces */
 684 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
 685 {
 686         mutex_lock(&probe_lock);
 687         return seq_list_start(&probe_list, *pos);
 688 }
 689
 690 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
 691 {
 692         return seq_list_next(v, &probe_list, pos);
 693 }
 694
 695 static void probes_seq_stop(struct seq_file *m, void *v)
 696 {
 697         mutex_unlock(&probe_lock);
 698 }
 699
 700 static int probes_seq_show(struct seq_file *m, void *v)
 701 {
 702         struct trace_probe *tp = v;
 703         int i, ret;
 704         char buf[MAX_ARGSTR_LEN + 1];
 705
 706         seq_printf(m, "%c", probe_is_return(tp) ? 'r' : 'p');
 707         seq_printf(m, ":%s", tp->call.name);
 708
 709         if (tp->symbol)
 710                 seq_printf(m, " %s+%u", probe_symbol(tp), tp->rp.kp.offset);
 711         else
 712                 seq_printf(m, " 0x%p", tp->rp.kp.addr);
 713
 714         for (i = 0; i < tp->nr_args; i++) {
 715                 ret = probe_arg_string(buf, MAX_ARGSTR_LEN, &tp->args[i].fetch);
 716                 if (ret < 0) {
 717                         pr_warning("Argument%d decoding error(%d).\n", i, ret);
 718                         return ret;
 719                 }
 720                 seq_printf(m, " %s=%s", tp->args[i].name, buf);
 721         }
 722         seq_printf(m, "\n");
 723         return 0;
 724 }
 725
 726 static const struct seq_operations probes_seq_op = {
 727         .start  = probes_seq_start,
 728         .next   = probes_seq_next,
 729         .stop   = probes_seq_stop,
 730         .show   = probes_seq_show
 731 };
 732
 733 static int probes_open(struct inode *inode, struct file *file)
 734 {
 735         if ((file->f_mode & FMODE_WRITE) &&
 736             (file->f_flags & O_TRUNC))
 737                 cleanup_all_probes();
 738
 739         return seq_open(file, &probes_seq_op);
 740 }
 741
 742 static int command_trace_probe(const char *buf)
 743 {
 744         char **argv;
 745         int argc = 0, ret = 0;
 746
 747         argv = argv_split(GFP_KERNEL, buf, &argc);
 748         if (!argv)
 749                 return -ENOMEM;
 750
 751         if (argc)
 752                 ret = create_trace_probe(argc, argv);
 753
 754         argv_free(argv);
 755         return ret;
 756 }
 757
 758 #define WRITE_BUFSIZE 128
 759
 760 static ssize_t probes_write(struct file *file, const char __user *buffer,
 761                             size_t count, loff_t *ppos)
 762 {
 763         char *kbuf, *tmp;
 764         int ret;
 765         size_t done;
 766         size_t size;
 767
 768         kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
 769         if (!kbuf)
 770                 return -ENOMEM;
 771
 772         ret = done = 0;
 773         while (done < count) {
 774                 size = count - done;
 775                 if (size >= WRITE_BUFSIZE)
 776                         size = WRITE_BUFSIZE - 1;
 777                 if (copy_from_user(kbuf, buffer + done, size)) {
 778                         ret = -EFAULT;
 779                         goto out;
 780                 }
 781                 kbuf[size] = '\0';
 782                 tmp = strchr(kbuf, '\n');
 783                 if (tmp) {
 784                         *tmp = '\0';
 785                         size = tmp - kbuf + 1;
 786                 } else if (done + size < count) {
 787                         pr_warning("Line length is too long: "
 788                                    "Should be less than %d.", WRITE_BUFSIZE);
 789                         ret = -EINVAL;
 790                         goto out;
 791                 }
 792                 done += size;
 793                 /* Remove comments */
 794                 tmp = strchr(kbuf, '#');
 795                 if (tmp)
 796                         *tmp = '\0';
 797
 798                 ret = command_trace_probe(kbuf);
 799                 if (ret)
 800                         goto out;
 801         }
 802         ret = done;
 803 out:
 804         kfree(kbuf);
 805         return ret;
 806 }
 807
 808 static const struct file_operations kprobe_events_ops = {
 809         .owner          = THIS_MODULE,
 810         .open           = probes_open,
 811         .read           = seq_read,
 812         .llseek         = seq_lseek,
 813         .release        = seq_release,
 814         .write          = probes_write,
 815 };
 816
 817 /* Probes profiling interfaces */
 818 static int probes_profile_seq_show(struct seq_file *m, void *v)
 819 {
 820         struct trace_probe *tp = v;
 821
 822         seq_printf(m, "  %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
 823                    tp->rp.kp.nmissed);
 824
 825         return 0;
 826 }
 827
 828 static const struct seq_operations profile_seq_op = {
 829         .start  = probes_seq_start,
 830         .next   = probes_seq_next,
 831         .stop   = probes_seq_stop,
 832         .show   = probes_profile_seq_show
 833 };
 834
 835 static int profile_open(struct inode *inode, struct file *file)
 836 {
 837         return seq_open(file, &profile_seq_op);
 838 }
 839
 840 static const struct file_operations kprobe_profile_ops = {
 841         .owner          = THIS_MODULE,
 842         .open           = profile_open,
 843         .read           = seq_read,
 844         .llseek         = seq_lseek,
 845         .release        = seq_release,
 846 };
 847
 848 /* Kprobe handler */
 849 static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
 850 {
 851         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
 852         struct kprobe_trace_entry *entry;
 853         struct ring_buffer_event *event;
 854         struct ring_buffer *buffer;
 855         int size, i, pc;
 856         unsigned long irq_flags;
 857         struct ftrace_event_call *call = &tp->call;
 858
 859         tp->nhit++;
 860
 861         local_save_flags(irq_flags);
 862         pc = preempt_count();
 863
 864         size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);
 865
 866         event = trace_current_buffer_lock_reserve(&buffer, call->id, size,
 867                                                   irq_flags, pc);
 868         if (!event)
 869                 return 0;
 870
 871         entry = ring_buffer_event_data(event);
 872         entry->nargs = tp->nr_args;
 873         entry->ip = (unsigned long)kp->addr;
 874         for (i = 0; i < tp->nr_args; i++)
 875                 entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
 876
 877         if (!filter_current_check_discard(buffer, call, entry, event))
 878                 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
 879         return 0;
 880 }
 881
 882 /* Kretprobe handler */
 883 static __kprobes int kretprobe_trace_func(struct kretprobe_instance *ri,
 884                                           struct pt_regs *regs)
 885 {
 886         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
 887         struct kretprobe_trace_entry *entry;
 888         struct ring_buffer_event *event;
 889         struct ring_buffer *buffer;
 890         int size, i, pc;
 891         unsigned long irq_flags;
 892         struct ftrace_event_call *call = &tp->call;
 893
 894         local_save_flags(irq_flags);
 895         pc = preempt_count();
 896
 897         size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);
 898
 899         event = trace_current_buffer_lock_reserve(&buffer, call->id, size,
 900                                                   irq_flags, pc);
 901         if (!event)
 902                 return 0;
 903
 904         entry = ring_buffer_event_data(event);
 905         entry->nargs = tp->nr_args;
 906         entry->func = (unsigned long)tp->rp.kp.addr;
 907         entry->ret_ip = (unsigned long)ri->ret_addr;
 908         for (i = 0; i < tp->nr_args; i++)
 909                 entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
 910
 911         if (!filter_current_check_discard(buffer, call, entry, event))
 912                 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
 913
 914         return 0;
 915 }
 916
 917 /* Event entry printers */
 918 enum print_line_t
 919 print_kprobe_event(struct trace_iterator *iter, int flags)
 920 {
 921         struct kprobe_trace_entry *field;
 922         struct trace_seq *s = &iter->seq;
 923         struct trace_event *event;
 924         struct trace_probe *tp;
 925         int i;
 926
 927         field = (struct kprobe_trace_entry *)iter->ent;
 928         event = ftrace_find_event(field->ent.type);
 929         tp = container_of(event, struct trace_probe, event);
 930
 931         if (!trace_seq_printf(s, "%s: (", tp->call.name))
 932                 goto partial;
 933
 934         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
 935                 goto partial;
 936
 937         if (!trace_seq_puts(s, ")"))
 938                 goto partial;
 939
 940         for (i = 0; i < field->nargs; i++)
 941                 if (!trace_seq_printf(s, " %s=%lx",
 942                                       tp->args[i].name, field->args[i]))
 943                         goto partial;
 944
 945         if (!trace_seq_puts(s, "\n"))
 946                 goto partial;
 947
 948         return TRACE_TYPE_HANDLED;
 949 partial:
 950         return TRACE_TYPE_PARTIAL_LINE;
 951 }
 952
 953 enum print_line_t
 954 print_kretprobe_event(struct trace_iterator *iter, int flags)
 955 {
 956         struct kretprobe_trace_entry *field;
 957         struct trace_seq *s = &iter->seq;
 958         struct trace_event *event;
 959         struct trace_probe *tp;
 960         int i;
 961
 962         field = (struct kretprobe_trace_entry *)iter->ent;
 963         event = ftrace_find_event(field->ent.type);
 964         tp = container_of(event, struct trace_probe, event);
 965
 966         if (!trace_seq_printf(s, "%s: (", tp->call.name))
 967                 goto partial;
 968
 969         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
 970                 goto partial;
 971
 972         if (!trace_seq_puts(s, " <- "))
 973                 goto partial;
 974
 975         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
 976                 goto partial;
 977
 978         if (!trace_seq_puts(s, ")"))
 979                 goto partial;
 980
 981         for (i = 0; i < field->nargs; i++)
 982                 if (!trace_seq_printf(s, " %s=%lx",
 983                                       tp->args[i].name, field->args[i]))
 984                         goto partial;
 985
 986         if (!trace_seq_puts(s, "\n"))
 987                 goto partial;
 988
 989         return TRACE_TYPE_HANDLED;
 990 partial:
 991         return TRACE_TYPE_PARTIAL_LINE;
 992 }
 993
 994 static int probe_event_enable(struct ftrace_event_call *call)
 995 {
 996         struct trace_probe *tp = (struct trace_probe *)call->data;
 997
 998         tp->flags |= TP_FLAG_TRACE;
 999         if (probe_is_return(tp))
1000                 return enable_kretprobe(&tp->rp);
1001         else
1002                 return enable_kprobe(&tp->rp.kp);
1003 }
1004
1005 static void probe_event_disable(struct ftrace_event_call *call)
1006 {
1007         struct trace_probe *tp = (struct trace_probe *)call->data;
1008
1009         tp->flags &= ~TP_FLAG_TRACE;
1010         if (!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE))) {
1011                 if (probe_is_return(tp))
1012                         disable_kretprobe(&tp->rp);
1013                 else
1014                         disable_kprobe(&tp->rp.kp);
1015         }
1016 }
1017
1018 static int probe_event_raw_init(struct ftrace_event_call *event_call)
1019 {
1020         INIT_LIST_HEAD(&event_call->fields);
1021
1022         return 0;
1023 }
1024
1025 #undef DEFINE_FIELD
1026 #define DEFINE_FIELD(type, item, name, is_signed)                       \
1027         do {                                                            \
1028                 ret = trace_define_field(event_call, #type, name,       \
1029                                          offsetof(typeof(field), item), \
1030                                          sizeof(field.item), is_signed, \
1031                                          FILTER_OTHER);                 \
1032                 if (ret)                                                \
1033                         return ret;                                     \
1034         } while (0)
1035
1036 static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1037 {
1038         int ret, i;
1039         struct kprobe_trace_entry field;
1040         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1041
1042         ret = trace_define_common_fields(event_call);
1043         if (!ret)
1044                 return ret;
1045
1046         DEFINE_FIELD(unsigned long, ip, "ip", 0);
1047         DEFINE_FIELD(int, nargs, "nargs", 1);
1048         /* Set argument names as fields */
1049         for (i = 0; i < tp->nr_args; i++)
1050                 DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
1051         return 0;
1052 }
1053
1054 static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1055 {
1056         int ret, i;
1057         struct kretprobe_trace_entry field;
1058         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1059
1060         ret = trace_define_common_fields(event_call);
1061         if (!ret)
1062                 return ret;
1063
1064         DEFINE_FIELD(unsigned long, func, "func", 0);
1065         DEFINE_FIELD(unsigned long, ret_ip, "ret_ip", 0);
1066         DEFINE_FIELD(int, nargs, "nargs", 1);
1067         /* Set argument names as fields */
1068         for (i = 0; i < tp->nr_args; i++)
1069                 DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
1070         return 0;
1071 }
1072
1073 static int __probe_event_show_format(struct trace_seq *s,
1074                                      struct trace_probe *tp, const char *fmt,
1075                                      const char *arg)
1076 {
1077         int i;
1078
1079         /* Show format */
1080         if (!trace_seq_printf(s, "\nprint fmt: \"%s", fmt))
1081                 return 0;
1082
1083         for (i = 0; i < tp->nr_args; i++)
1084                 if (!trace_seq_printf(s, " %s=%%lx", tp->args[i].name))
1085                         return 0;
1086
1087         if (!trace_seq_printf(s, "\", %s", arg))
1088                 return 0;
1089
1090         for (i = 0; i < tp->nr_args; i++)
1091                 if (!trace_seq_printf(s, ", REC->%s", tp->args[i].name))
1092                         return 0;
1093
1094         return trace_seq_puts(s, "\n");
1095 }
1096
1097 #undef SHOW_FIELD
1098 #define SHOW_FIELD(type, item, name)                                    \
1099         do {                                                            \
1100                 ret = trace_seq_printf(s, "\tfield: " #type " %s;\t"    \
1101                                 "offset:%u;\tsize:%u;\n", name,         \
1102                                 (unsigned int)offsetof(typeof(field), item),\
1103                                 (unsigned int)sizeof(type));            \
1104                 if (!ret)                                               \
1105                         return 0;                                       \
1106         } while (0)
1107
1108 static int kprobe_event_show_format(struct ftrace_event_call *call,
1109                                     struct trace_seq *s)
1110 {
1111         struct kprobe_trace_entry field __attribute__((unused));
1112         int ret, i;
1113         struct trace_probe *tp = (struct trace_probe *)call->data;
1114
1115         SHOW_FIELD(unsigned long, ip, "ip");
1116         SHOW_FIELD(int, nargs, "nargs");
1117
1118         /* Show fields */
1119         for (i = 0; i < tp->nr_args; i++)
1120                 SHOW_FIELD(unsigned long, args[i], tp->args[i].name);
1121         trace_seq_puts(s, "\n");
1122
1123         return __probe_event_show_format(s, tp, "(%lx)", "REC->ip");
1124 }
1125
1126 static int kretprobe_event_show_format(struct ftrace_event_call *call,
1127                                        struct trace_seq *s)
1128 {
1129         struct kretprobe_trace_entry field __attribute__((unused));
1130         int ret, i;
1131         struct trace_probe *tp = (struct trace_probe *)call->data;
1132
1133         SHOW_FIELD(unsigned long, func, "func");
1134         SHOW_FIELD(unsigned long, ret_ip, "ret_ip");
1135         SHOW_FIELD(int, nargs, "nargs");
1136
1137         /* Show fields */
1138         for (i = 0; i < tp->nr_args; i++)
1139                 SHOW_FIELD(unsigned long, args[i], tp->args[i].name);
1140         trace_seq_puts(s, "\n");
1141
1142         return __probe_event_show_format(s, tp, "(%lx <- %lx)",
1143                                           "REC->func, REC->ret_ip");
1144 }
1145
1146 #ifdef CONFIG_EVENT_PROFILE
1147
1148 /* Kprobe profile handler */
1149 static __kprobes int kprobe_profile_func(struct kprobe *kp,
1150                                          struct pt_regs *regs)
1151 {
1152         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1153         struct ftrace_event_call *call = &tp->call;
1154         struct kprobe_trace_entry *entry;
1155         struct trace_entry *ent;
1156         int size, __size, i, pc, __cpu;
1157         unsigned long irq_flags;
1158         char *raw_data;
1159
1160         pc = preempt_count();
1161         __size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);
1162         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1163         size -= sizeof(u32);
1164         if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE,
1165                      "profile buffer not large enough"))
1166                 return 0;
1167
1168         /*
1169          * Protect the non nmi buffer
1170          * This also protects the rcu read side
1171          */
1172         local_irq_save(irq_flags);
1173         __cpu = smp_processor_id();
1174
1175         if (in_nmi())
1176                 raw_data = rcu_dereference(trace_profile_buf_nmi);
1177         else
1178                 raw_data = rcu_dereference(trace_profile_buf);
1179
1180         if (!raw_data)
1181                 goto end;
1182
1183         raw_data = per_cpu_ptr(raw_data, __cpu);
1184         /* Zero dead bytes from alignment to avoid buffer leak to userspace */
1185         *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
1186         entry = (struct kprobe_trace_entry *)raw_data;
1187         ent = &entry->ent;
1188
1189         tracing_generic_entry_update(ent, irq_flags, pc);
1190         ent->type = call->id;
1191         entry->nargs = tp->nr_args;
1192         entry->ip = (unsigned long)kp->addr;
1193         for (i = 0; i < tp->nr_args; i++)
1194                 entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
1195         perf_tp_event(call->id, entry->ip, 1, entry, size);
1196 end:
1197         local_irq_restore(irq_flags);
1198         return 0;
1199 }
1200
1201 /* Kretprobe profile handler */
1202 static __kprobes int kretprobe_profile_func(struct kretprobe_instance *ri,
1203                                             struct pt_regs *regs)
1204 {
1205         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1206         struct ftrace_event_call *call = &tp->call;
1207         struct kretprobe_trace_entry *entry;
1208         struct trace_entry *ent;
1209         int size, __size, i, pc, __cpu;
1210         unsigned long irq_flags;
1211         char *raw_data;
1212
1213         pc = preempt_count();
1214         __size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);
1215         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1216         size -= sizeof(u32);
1217         if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE,
1218                      "profile buffer not large enough"))
1219                 return 0;
1220
1221         /*
1222          * Protect the non nmi buffer
1223          * This also protects the rcu read side
1224          */
1225         local_irq_save(irq_flags);
1226         __cpu = smp_processor_id();
1227
1228         if (in_nmi())
1229                 raw_data = rcu_dereference(trace_profile_buf_nmi);
1230         else
1231                 raw_data = rcu_dereference(trace_profile_buf);
1232
1233         if (!raw_data)
1234                 goto end;
1235
1236         raw_data = per_cpu_ptr(raw_data, __cpu);
1237         /* Zero dead bytes from alignment to avoid buffer leak to userspace */
1238         *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
1239         entry = (struct kretprobe_trace_entry *)raw_data;
1240         ent = &entry->ent;
1241
1242         tracing_generic_entry_update(ent, irq_flags, pc);
1243         ent->type = call->id;
1244         entry->nargs = tp->nr_args;
1245         entry->func = (unsigned long)tp->rp.kp.addr;
1246         entry->ret_ip = (unsigned long)ri->ret_addr;
1247         for (i = 0; i < tp->nr_args; i++)
1248                 entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
1249         perf_tp_event(call->id, entry->ret_ip, 1, entry, size);
1250 end:
1251         local_irq_restore(irq_flags);
1252         return 0;
1253 }
1254
1255 static int probe_profile_enable(struct ftrace_event_call *call)
1256 {
1257         struct trace_probe *tp = (struct trace_probe *)call->data;
1258
1259         tp->flags |= TP_FLAG_PROFILE;
1260
1261         if (probe_is_return(tp))
1262                 return enable_kretprobe(&tp->rp);
1263         else
1264                 return enable_kprobe(&tp->rp.kp);
1265 }
1266
1267 static void probe_profile_disable(struct ftrace_event_call *call)
1268 {
1269         struct trace_probe *tp = (struct trace_probe *)call->data;
1270
1271         tp->flags &= ~TP_FLAG_PROFILE;
1272
1273         if (!(tp->flags & TP_FLAG_TRACE)) {
1274                 if (probe_is_return(tp))
1275                         disable_kretprobe(&tp->rp);
1276                 else
1277                         disable_kprobe(&tp->rp.kp);
1278         }
1279 }
1280 #endif  /* CONFIG_EVENT_PROFILE */
1281
1282
1283 static __kprobes
1284 int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1285 {
1286         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1287
1288         if (tp->flags & TP_FLAG_TRACE)
1289                 kprobe_trace_func(kp, regs);
1290 #ifdef CONFIG_EVENT_PROFILE
1291         if (tp->flags & TP_FLAG_PROFILE)
1292                 kprobe_profile_func(kp, regs);
1293 #endif  /* CONFIG_EVENT_PROFILE */
1294         return 0;       /* We don't tweek kernel, so just return 0 */
1295 }
1296
1297 static __kprobes
1298 int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1299 {
1300         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1301
1302         if (tp->flags & TP_FLAG_TRACE)
1303                 kretprobe_trace_func(ri, regs);
1304 #ifdef CONFIG_EVENT_PROFILE
1305         if (tp->flags & TP_FLAG_PROFILE)
1306                 kretprobe_profile_func(ri, regs);
1307 #endif  /* CONFIG_EVENT_PROFILE */
1308         return 0;       /* We don't tweek kernel, so just return 0 */
1309 }
1310
1311 static int register_probe_event(struct trace_probe *tp)
1312 {
1313         struct ftrace_event_call *call = &tp->call;
1314         int ret;
1315
1316         /* Initialize ftrace_event_call */
1317         if (probe_is_return(tp)) {
1318                 tp->event.trace = print_kretprobe_event;
1319                 call->raw_init = probe_event_raw_init;
1320                 call->show_format = kretprobe_event_show_format;
1321                 call->define_fields = kretprobe_event_define_fields;
1322         } else {
1323                 tp->event.trace = print_kprobe_event;
1324                 call->raw_init = probe_event_raw_init;
1325                 call->show_format = kprobe_event_show_format;
1326                 call->define_fields = kprobe_event_define_fields;
1327         }
1328         call->event = &tp->event;
1329         call->id = register_ftrace_event(&tp->event);
1330         if (!call->id)
1331                 return -ENODEV;
1332         call->enabled = 0;
1333         call->regfunc = probe_event_enable;
1334         call->unregfunc = probe_event_disable;
1335
1336 #ifdef CONFIG_EVENT_PROFILE
1337         atomic_set(&call->profile_count, -1);
1338         call->profile_enable = probe_profile_enable;
1339         call->profile_disable = probe_profile_disable;
1340 #endif
1341         call->data = tp;
1342         ret = trace_add_event_call(call);
1343         if (ret) {
1344                 pr_info("Failed to register kprobe event: %s\n", call->name);
1345                 unregister_ftrace_event(&tp->event);
1346         }
1347         return ret;
1348 }
1349
1350 static void unregister_probe_event(struct trace_probe *tp)
1351 {
1352         /* tp->event is unregistered in trace_remove_event_call() */
1353         trace_remove_event_call(&tp->call);
1354 }
1355
1356 /* Make a debugfs interface for controling probe points */
1357 static __init int init_kprobe_trace(void)
1358 {
1359         struct dentry *d_tracer;
1360         struct dentry *entry;
1361
1362         d_tracer = tracing_init_dentry();
1363         if (!d_tracer)
1364                 return 0;
1365
1366         entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
1367                                     NULL, &kprobe_events_ops);
1368
1369         /* Event list interface */
1370         if (!entry)
1371                 pr_warning("Could not create debugfs "
1372                            "'kprobe_events' entry\n");
1373
1374         /* Profile interface */
1375         entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
1376                                     NULL, &kprobe_profile_ops);
1377
1378         if (!entry)
1379                 pr_warning("Could not create debugfs "
1380                            "'kprobe_profile' entry\n");
1381         return 0;
1382 }
1383 fs_initcall(init_kprobe_trace);
1384
1385
1386 #ifdef CONFIG_FTRACE_STARTUP_TEST
1387
1388 static int kprobe_trace_selftest_target(int a1, int a2, int a3,
1389                                         int a4, int a5, int a6)
1390 {
1391         return a1 + a2 + a3 + a4 + a5 + a6;
1392 }
1393
1394 static __init int kprobe_trace_self_tests_init(void)
1395 {
1396         int ret;
1397         int (*target)(int, int, int, int, int, int);
1398
1399         target = kprobe_trace_selftest_target;
1400
1401         pr_info("Testing kprobe tracing: ");
1402
1403         ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target "
1404                                   "a1 a2 a3 a4 a5 a6");
1405         if (WARN_ON_ONCE(ret))
1406                 pr_warning("error enabling function entry\n");
1407
1408         ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target "
1409                                   "ra rv");
1410         if (WARN_ON_ONCE(ret))
1411                 pr_warning("error enabling function return\n");
1412
1413         ret = target(1, 2, 3, 4, 5, 6);
1414
1415         cleanup_all_probes();
1416
1417         pr_cont("OK\n");
1418         return 0;
1419 }
1420
1421 late_initcall(kprobe_trace_self_tests_init);
1422
1423 #endif