SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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_ip(struct pt_regs *regs, void *dummy)
  89 {
  90         return instruction_pointer(regs);
  91 }
  92
  93 static __kprobes unsigned long fetch_stack_address(struct pt_regs *regs,
  94                                                    void *dummy)
  95 {
  96         return kernel_stack_pointer(regs);
  97 }
  98
  99 /* Memory fetching by symbol */
 100 struct symbol_cache {
 101         char *symbol;
 102         long offset;
 103         unsigned long addr;
 104 };
 105
 106 static unsigned long update_symbol_cache(struct symbol_cache *sc)
 107 {
 108         sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
 109         if (sc->addr)
 110                 sc->addr += sc->offset;
 111         return sc->addr;
 112 }
 113
 114 static void free_symbol_cache(struct symbol_cache *sc)
 115 {
 116         kfree(sc->symbol);
 117         kfree(sc);
 118 }
 119
 120 static struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
 121 {
 122         struct symbol_cache *sc;
 123
 124         if (!sym || strlen(sym) == 0)
 125                 return NULL;
 126         sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
 127         if (!sc)
 128                 return NULL;
 129
 130         sc->symbol = kstrdup(sym, GFP_KERNEL);
 131         if (!sc->symbol) {
 132                 kfree(sc);
 133                 return NULL;
 134         }
 135         sc->offset = offset;
 136
 137         update_symbol_cache(sc);
 138         return sc;
 139 }
 140
 141 static __kprobes unsigned long fetch_symbol(struct pt_regs *regs, void *data)
 142 {
 143         struct symbol_cache *sc = data;
 144
 145         if (sc->addr)
 146                 return fetch_memory(regs, (void *)sc->addr);
 147         else
 148                 return 0;
 149 }
 150
 151 /* Special indirect memory access interface */
 152 struct indirect_fetch_data {
 153         struct fetch_func orig;
 154         long offset;
 155 };
 156
 157 static __kprobes unsigned long fetch_indirect(struct pt_regs *regs, void *data)
 158 {
 159         struct indirect_fetch_data *ind = data;
 160         unsigned long addr;
 161
 162         addr = call_fetch(&ind->orig, regs);
 163         if (addr) {
 164                 addr += ind->offset;
 165                 return fetch_memory(regs, (void *)addr);
 166         } else
 167                 return 0;
 168 }
 169
 170 static __kprobes void free_indirect_fetch_data(struct indirect_fetch_data *data)
 171 {
 172         if (data->orig.func == fetch_indirect)
 173                 free_indirect_fetch_data(data->orig.data);
 174         else if (data->orig.func == fetch_symbol)
 175                 free_symbol_cache(data->orig.data);
 176         kfree(data);
 177 }
 178
 179 /**
 180  * Kprobe tracer core functions
 181  */
 182
 183 struct probe_arg {
 184         struct fetch_func       fetch;
 185         const char              *name;
 186 };
 187
 188 /* Flags for trace_probe */
 189 #define TP_FLAG_TRACE   1
 190 #define TP_FLAG_PROFILE 2
 191
 192 struct trace_probe {
 193         struct list_head        list;
 194         struct kretprobe        rp;     /* Use rp.kp for kprobe use */
 195         unsigned long           nhit;
 196         unsigned int            flags;  /* For TP_FLAG_* */
 197         const char              *symbol;        /* symbol name */
 198         struct ftrace_event_call        call;
 199         struct trace_event              event;
 200         unsigned int            nr_args;
 201         struct probe_arg        args[];
 202 };
 203
 204 #define SIZEOF_TRACE_PROBE(n)                   \
 205         (offsetof(struct trace_probe, args) +   \
 206         (sizeof(struct probe_arg) * (n)))
 207
 208 static __kprobes int probe_is_return(struct trace_probe *tp)
 209 {
 210         return tp->rp.handler != NULL;
 211 }
 212
 213 static __kprobes const char *probe_symbol(struct trace_probe *tp)
 214 {
 215         return tp->symbol ? tp->symbol : "unknown";
 216 }
 217
 218 static int probe_arg_string(char *buf, size_t n, struct fetch_func *ff)
 219 {
 220         int ret = -EINVAL;
 221
 222         if (ff->func == fetch_argument)
 223                 ret = snprintf(buf, n, "a%lu", (unsigned long)ff->data);
 224         else if (ff->func == fetch_register) {
 225                 const char *name;
 226                 name = regs_query_register_name((unsigned int)((long)ff->data));
 227                 ret = snprintf(buf, n, "%%%s", name);
 228         } else if (ff->func == fetch_stack)
 229                 ret = snprintf(buf, n, "s%lu", (unsigned long)ff->data);
 230         else if (ff->func == fetch_memory)
 231                 ret = snprintf(buf, n, "@0x%p", ff->data);
 232         else if (ff->func == fetch_symbol) {
 233                 struct symbol_cache *sc = ff->data;
 234                 ret = snprintf(buf, n, "@%s%+ld", sc->symbol, sc->offset);
 235         } else if (ff->func == fetch_retvalue)
 236                 ret = snprintf(buf, n, "rv");
 237         else if (ff->func == fetch_ip)
 238                 ret = snprintf(buf, n, "ra");
 239         else if (ff->func == fetch_stack_address)
 240                 ret = snprintf(buf, n, "sa");
 241         else if (ff->func == fetch_indirect) {
 242                 struct indirect_fetch_data *id = ff->data;
 243                 size_t l = 0;
 244                 ret = snprintf(buf, n, "%+ld(", id->offset);
 245                 if (ret >= n)
 246                         goto end;
 247                 l += ret;
 248                 ret = probe_arg_string(buf + l, n - l, &id->orig);
 249                 if (ret < 0)
 250                         goto end;
 251                 l += ret;
 252                 ret = snprintf(buf + l, n - l, ")");
 253                 ret += l;
 254         }
 255 end:
 256         if (ret >= n)
 257                 return -ENOSPC;
 258         return ret;
 259 }
 260
 261 static int register_probe_event(struct trace_probe *tp);
 262 static void unregister_probe_event(struct trace_probe *tp);
 263
 264 static DEFINE_MUTEX(probe_lock);
 265 static LIST_HEAD(probe_list);
 266
 267 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
 268 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
 269                                 struct pt_regs *regs);
 270
 271 /*
 272  * Allocate new trace_probe and initialize it (including kprobes).
 273  */
 274 static struct trace_probe *alloc_trace_probe(const char *group,
 275                                              const char *event,
 276                                              void *addr,
 277                                              const char *symbol,
 278                                              unsigned long offs,
 279                                              int nargs, int is_return)
 280 {
 281         struct trace_probe *tp;
 282
 283         tp = kzalloc(SIZEOF_TRACE_PROBE(nargs), GFP_KERNEL);
 284         if (!tp)
 285                 return ERR_PTR(-ENOMEM);
 286
 287         if (symbol) {
 288                 tp->symbol = kstrdup(symbol, GFP_KERNEL);
 289                 if (!tp->symbol)
 290                         goto error;
 291                 tp->rp.kp.symbol_name = tp->symbol;
 292                 tp->rp.kp.offset = offs;
 293         } else
 294                 tp->rp.kp.addr = addr;
 295
 296         if (is_return)
 297                 tp->rp.handler = kretprobe_dispatcher;
 298         else
 299                 tp->rp.kp.pre_handler = kprobe_dispatcher;
 300
 301         if (!event)
 302                 goto error;
 303         tp->call.name = kstrdup(event, GFP_KERNEL);
 304         if (!tp->call.name)
 305                 goto error;
 306
 307         if (!group)
 308                 goto error;
 309         tp->call.system = kstrdup(group, GFP_KERNEL);
 310         if (!tp->call.system)
 311                 goto error;
 312
 313         INIT_LIST_HEAD(&tp->list);
 314         return tp;
 315 error:
 316         kfree(tp->call.name);
 317         kfree(tp->symbol);
 318         kfree(tp);
 319         return ERR_PTR(-ENOMEM);
 320 }
 321
 322 static void free_probe_arg(struct probe_arg *arg)
 323 {
 324         if (arg->fetch.func == fetch_symbol)
 325                 free_symbol_cache(arg->fetch.data);
 326         else if (arg->fetch.func == fetch_indirect)
 327                 free_indirect_fetch_data(arg->fetch.data);
 328         kfree(arg->name);
 329 }
 330
 331 static void free_trace_probe(struct trace_probe *tp)
 332 {
 333         int i;
 334
 335         for (i = 0; i < tp->nr_args; i++)
 336                 free_probe_arg(&tp->args[i]);
 337
 338         kfree(tp->call.system);
 339         kfree(tp->call.name);
 340         kfree(tp->symbol);
 341         kfree(tp);
 342 }
 343
 344 static struct trace_probe *find_probe_event(const char *event)
 345 {
 346         struct trace_probe *tp;
 347
 348         list_for_each_entry(tp, &probe_list, list)
 349                 if (!strcmp(tp->call.name, event))
 350                         return tp;
 351         return NULL;
 352 }
 353
 354 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
 355 static void unregister_trace_probe(struct trace_probe *tp)
 356 {
 357         if (probe_is_return(tp))
 358                 unregister_kretprobe(&tp->rp);
 359         else
 360                 unregister_kprobe(&tp->rp.kp);
 361         list_del(&tp->list);
 362         unregister_probe_event(tp);
 363 }
 364
 365 /* Register a trace_probe and probe_event */
 366 static int register_trace_probe(struct trace_probe *tp)
 367 {
 368         struct trace_probe *old_tp;
 369         int ret;
 370
 371         mutex_lock(&probe_lock);
 372
 373         /* register as an event */
 374         old_tp = find_probe_event(tp->call.name);
 375         if (old_tp) {
 376                 /* delete old event */
 377                 unregister_trace_probe(old_tp);
 378                 free_trace_probe(old_tp);
 379         }
 380         ret = register_probe_event(tp);
 381         if (ret) {
 382                 pr_warning("Faild to register probe event(%d)\n", ret);
 383                 goto end;
 384         }
 385
 386         tp->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 387         if (probe_is_return(tp))
 388                 ret = register_kretprobe(&tp->rp);
 389         else
 390                 ret = register_kprobe(&tp->rp.kp);
 391
 392         if (ret) {
 393                 pr_warning("Could not insert probe(%d)\n", ret);
 394                 if (ret == -EILSEQ) {
 395                         pr_warning("Probing address(0x%p) is not an "
 396                                    "instruction boundary.\n",
 397                                    tp->rp.kp.addr);
 398                         ret = -EINVAL;
 399                 }
 400                 unregister_probe_event(tp);
 401         } else
 402                 list_add_tail(&tp->list, &probe_list);
 403 end:
 404         mutex_unlock(&probe_lock);
 405         return ret;
 406 }
 407
 408 /* Split symbol and offset. */
 409 static int split_symbol_offset(char *symbol, unsigned long *offset)
 410 {
 411         char *tmp;
 412         int ret;
 413
 414         if (!offset)
 415                 return -EINVAL;
 416
 417         tmp = strchr(symbol, '+');
 418         if (tmp) {
 419                 /* skip sign because strict_strtol doesn't accept '+' */
 420                 ret = strict_strtoul(tmp + 1, 0, offset);
 421                 if (ret)
 422                         return ret;
 423                 *tmp = '\0';
 424         } else
 425                 *offset = 0;
 426         return 0;
 427 }
 428
 429 #define PARAM_MAX_ARGS 16
 430 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
 431
 432 static int parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
 433 {
 434         int ret = 0;
 435         unsigned long param;
 436         long offset;
 437         char *tmp;
 438
 439         switch (arg[0]) {
 440         case 'a':       /* argument */
 441                 ret = strict_strtoul(arg + 1, 10, &param);
 442                 if (ret || param > PARAM_MAX_ARGS)
 443                         ret = -EINVAL;
 444                 else {
 445                         ff->func = fetch_argument;
 446                         ff->data = (void *)param;
 447                 }
 448                 break;
 449         case 'r':       /* retval or retaddr */
 450                 if (is_return && arg[1] == 'v') {
 451                         ff->func = fetch_retvalue;
 452                         ff->data = NULL;
 453                 } else if (is_return && arg[1] == 'a') {
 454                         ff->func = fetch_ip;
 455                         ff->data = NULL;
 456                 } else
 457                         ret = -EINVAL;
 458                 break;
 459         case '%':       /* named register */
 460                 ret = regs_query_register_offset(arg + 1);
 461                 if (ret >= 0) {
 462                         ff->func = fetch_register;
 463                         ff->data = (void *)(unsigned long)ret;
 464                         ret = 0;
 465                 }
 466                 break;
 467         case 's':       /* stack */
 468                 if (arg[1] == 'a') {
 469                         ff->func = fetch_stack_address;
 470                         ff->data = NULL;
 471                 } else {
 472                         ret = strict_strtoul(arg + 1, 10, &param);
 473                         if (ret || param > PARAM_MAX_STACK)
 474                                 ret = -EINVAL;
 475                         else {
 476                                 ff->func = fetch_stack;
 477                                 ff->data = (void *)param;
 478                         }
 479                 }
 480                 break;
 481         case '@':       /* memory or symbol */
 482                 if (isdigit(arg[1])) {
 483                         ret = strict_strtoul(arg + 1, 0, &param);
 484                         if (ret)
 485                                 break;
 486                         ff->func = fetch_memory;
 487                         ff->data = (void *)param;
 488                 } else {
 489                         ret = split_symbol_offset(arg + 1, &offset);
 490                         if (ret)
 491                                 break;
 492                         ff->data = alloc_symbol_cache(arg + 1,
 493                                                               offset);
 494                         if (ff->data)
 495                                 ff->func = fetch_symbol;
 496                         else
 497                                 ret = -EINVAL;
 498                 }
 499                 break;
 500         case '+':       /* indirect memory */
 501         case '-':
 502                 tmp = strchr(arg, '(');
 503                 if (!tmp) {
 504                         ret = -EINVAL;
 505                         break;
 506                 }
 507                 *tmp = '\0';
 508                 ret = strict_strtol(arg + 1, 0, &offset);
 509                 if (ret)
 510                         break;
 511                 if (arg[0] == '-')
 512                         offset = -offset;
 513                 arg = tmp + 1;
 514                 tmp = strrchr(arg, ')');
 515                 if (tmp) {
 516                         struct indirect_fetch_data *id;
 517                         *tmp = '\0';
 518                         id = kzalloc(sizeof(struct indirect_fetch_data),
 519                                      GFP_KERNEL);
 520                         if (!id)
 521                                 return -ENOMEM;
 522                         id->offset = offset;
 523                         ret = parse_probe_arg(arg, &id->orig, is_return);
 524                         if (ret)
 525                                 kfree(id);
 526                         else {
 527                                 ff->func = fetch_indirect;
 528                                 ff->data = (void *)id;
 529                         }
 530                 } else
 531                         ret = -EINVAL;
 532                 break;
 533         default:
 534                 /* TODO: support custom handler */
 535                 ret = -EINVAL;
 536         }
 537         return ret;
 538 }
 539
 540 static int create_trace_probe(int argc, char **argv)
 541 {
 542         /*
 543          * Argument syntax:
 544          *  - Add kprobe: p[:[GRP/]EVENT] KSYM[+OFFS]|KADDR [FETCHARGS]
 545          *  - Add kretprobe: r[:[GRP/]EVENT] KSYM[+0] [FETCHARGS]
 546          * Fetch args:
 547          *  aN  : fetch Nth of function argument. (N:0-)
 548          *  rv  : fetch return value
 549          *  ra  : fetch return address
 550          *  sa  : fetch stack address
 551          *  sN  : fetch Nth of stack (N:0-)
 552          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 553          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 554          *  %REG        : fetch register REG
 555          * Indirect memory fetch:
 556          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 557          * Alias name of args:
 558          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 559          */
 560         struct trace_probe *tp;
 561         int i, ret = 0;
 562         int is_return = 0;
 563         char *symbol = NULL, *event = NULL, *arg = NULL, *group = NULL;
 564         unsigned long offset = 0;
 565         void *addr = NULL;
 566         char buf[MAX_EVENT_NAME_LEN];
 567
 568         if (argc < 2)
 569                 return -EINVAL;
 570
 571         if (argv[0][0] == 'p')
 572                 is_return = 0;
 573         else if (argv[0][0] == 'r')
 574                 is_return = 1;
 575         else
 576                 return -EINVAL;
 577
 578         if (argv[0][1] == ':') {
 579                 event = &argv[0][2];
 580                 if (strchr(event, '/')) {
 581                         group = event;
 582                         event = strchr(group, '/') + 1;
 583                         event[-1] = '\0';
 584                         if (strlen(group) == 0) {
 585                                 pr_info("Group name is not specifiled\n");
 586                                 return -EINVAL;
 587                         }
 588                 }
 589                 if (strlen(event) == 0) {
 590                         pr_info("Event name is not specifiled\n");
 591                         return -EINVAL;
 592                 }
 593         }
 594
 595         if (isdigit(argv[1][0])) {
 596                 if (is_return)
 597                         return -EINVAL;
 598                 /* an address specified */
 599                 ret = strict_strtoul(&argv[0][2], 0, (unsigned long *)&addr);
 600                 if (ret)
 601                         return ret;
 602         } else {
 603                 /* a symbol specified */
 604                 symbol = argv[1];
 605                 /* TODO: support .init module functions */
 606                 ret = split_symbol_offset(symbol, &offset);
 607                 if (ret)
 608                         return ret;
 609                 if (offset && is_return)
 610                         return -EINVAL;
 611         }
 612         argc -= 2; argv += 2;
 613
 614         /* setup a probe */
 615         if (!group)
 616                 group = KPROBE_EVENT_SYSTEM;
 617         if (!event) {
 618                 /* Make a new event name */
 619                 if (symbol)
 620                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c@%s%+ld",
 621                                  is_return ? 'r' : 'p', symbol, offset);
 622                 else
 623                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c@0x%p",
 624                                  is_return ? 'r' : 'p', addr);
 625                 event = buf;
 626         }
 627         tp = alloc_trace_probe(group, event, addr, symbol, offset, argc,
 628                                is_return);
 629         if (IS_ERR(tp))
 630                 return PTR_ERR(tp);
 631
 632         /* parse arguments */
 633         ret = 0;
 634         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 635                 /* Parse argument name */
 636                 arg = strchr(argv[i], '=');
 637                 if (arg)
 638                         *arg++ = '\0';
 639                 else
 640                         arg = argv[i];
 641                 tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
 642
 643                 /* Parse fetch argument */
 644                 if (strlen(arg) > MAX_ARGSTR_LEN) {
 645                         pr_info("Argument%d(%s) is too long.\n", i, arg);
 646                         ret = -ENOSPC;
 647                         goto error;
 648                 }
 649                 ret = parse_probe_arg(arg, &tp->args[i].fetch, is_return);
 650                 if (ret)
 651                         goto error;
 652         }
 653         tp->nr_args = i;
 654
 655         ret = register_trace_probe(tp);
 656         if (ret)
 657                 goto error;
 658         return 0;
 659
 660 error:
 661         free_trace_probe(tp);
 662         return ret;
 663 }
 664
 665 static void cleanup_all_probes(void)
 666 {
 667         struct trace_probe *tp;
 668
 669         mutex_lock(&probe_lock);
 670         /* TODO: Use batch unregistration */
 671         while (!list_empty(&probe_list)) {
 672                 tp = list_entry(probe_list.next, struct trace_probe, list);
 673                 unregister_trace_probe(tp);
 674                 free_trace_probe(tp);
 675         }
 676         mutex_unlock(&probe_lock);
 677 }
 678
 679
 680 /* Probes listing interfaces */
 681 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
 682 {
 683         mutex_lock(&probe_lock);
 684         return seq_list_start(&probe_list, *pos);
 685 }
 686
 687 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
 688 {
 689         return seq_list_next(v, &probe_list, pos);
 690 }
 691
 692 static void probes_seq_stop(struct seq_file *m, void *v)
 693 {
 694         mutex_unlock(&probe_lock);
 695 }
 696
 697 static int probes_seq_show(struct seq_file *m, void *v)
 698 {
 699         struct trace_probe *tp = v;
 700         int i, ret;
 701         char buf[MAX_ARGSTR_LEN + 1];
 702
 703         seq_printf(m, "%c", probe_is_return(tp) ? 'r' : 'p');
 704         seq_printf(m, ":%s", tp->call.name);
 705
 706         if (tp->symbol)
 707                 seq_printf(m, " %s+%u", probe_symbol(tp), tp->rp.kp.offset);
 708         else
 709                 seq_printf(m, " 0x%p", tp->rp.kp.addr);
 710
 711         for (i = 0; i < tp->nr_args; i++) {
 712                 ret = probe_arg_string(buf, MAX_ARGSTR_LEN, &tp->args[i].fetch);
 713                 if (ret < 0) {
 714                         pr_warning("Argument%d decoding error(%d).\n", i, ret);
 715                         return ret;
 716                 }
 717                 seq_printf(m, " %s=%s", tp->args[i].name, buf);
 718         }
 719         seq_printf(m, "\n");
 720         return 0;
 721 }
 722
 723 static const struct seq_operations probes_seq_op = {
 724         .start  = probes_seq_start,
 725         .next   = probes_seq_next,
 726         .stop   = probes_seq_stop,
 727         .show   = probes_seq_show
 728 };
 729
 730 static int probes_open(struct inode *inode, struct file *file)
 731 {
 732         if ((file->f_mode & FMODE_WRITE) &&
 733             (file->f_flags & O_TRUNC))
 734                 cleanup_all_probes();
 735
 736         return seq_open(file, &probes_seq_op);
 737 }
 738
 739 static int command_trace_probe(const char *buf)
 740 {
 741         char **argv;
 742         int argc = 0, ret = 0;
 743
 744         argv = argv_split(GFP_KERNEL, buf, &argc);
 745         if (!argv)
 746                 return -ENOMEM;
 747
 748         if (argc)
 749                 ret = create_trace_probe(argc, argv);
 750
 751         argv_free(argv);
 752         return ret;
 753 }
 754
 755 #define WRITE_BUFSIZE 128
 756
 757 static ssize_t probes_write(struct file *file, const char __user *buffer,
 758                             size_t count, loff_t *ppos)
 759 {
 760         char *kbuf, *tmp;
 761         int ret;
 762         size_t done;
 763         size_t size;
 764
 765         kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
 766         if (!kbuf)
 767                 return -ENOMEM;
 768
 769         ret = done = 0;
 770         while (done < count) {
 771                 size = count - done;
 772                 if (size >= WRITE_BUFSIZE)
 773                         size = WRITE_BUFSIZE - 1;
 774                 if (copy_from_user(kbuf, buffer + done, size)) {
 775                         ret = -EFAULT;
 776                         goto out;
 777                 }
 778                 kbuf[size] = '\0';
 779                 tmp = strchr(kbuf, '\n');
 780                 if (tmp) {
 781                         *tmp = '\0';
 782                         size = tmp - kbuf + 1;
 783                 } else if (done + size < count) {
 784                         pr_warning("Line length is too long: "
 785                                    "Should be less than %d.", WRITE_BUFSIZE);
 786                         ret = -EINVAL;
 787                         goto out;
 788                 }
 789                 done += size;
 790                 /* Remove comments */
 791                 tmp = strchr(kbuf, '#');
 792                 if (tmp)
 793                         *tmp = '\0';
 794
 795                 ret = command_trace_probe(kbuf);
 796                 if (ret)
 797                         goto out;
 798         }
 799         ret = done;
 800 out:
 801         kfree(kbuf);
 802         return ret;
 803 }
 804
 805 static const struct file_operations kprobe_events_ops = {
 806         .owner          = THIS_MODULE,
 807         .open           = probes_open,
 808         .read           = seq_read,
 809         .llseek         = seq_lseek,
 810         .release        = seq_release,
 811         .write          = probes_write,
 812 };
 813
 814 /* Probes profiling interfaces */
 815 static int probes_profile_seq_show(struct seq_file *m, void *v)
 816 {
 817         struct trace_probe *tp = v;
 818
 819         seq_printf(m, "  %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
 820                    tp->rp.kp.nmissed);
 821
 822         return 0;
 823 }
 824
 825 static const struct seq_operations profile_seq_op = {
 826         .start  = probes_seq_start,
 827         .next   = probes_seq_next,
 828         .stop   = probes_seq_stop,
 829         .show   = probes_profile_seq_show
 830 };
 831
 832 static int profile_open(struct inode *inode, struct file *file)
 833 {
 834         return seq_open(file, &profile_seq_op);
 835 }
 836
 837 static const struct file_operations kprobe_profile_ops = {
 838         .owner          = THIS_MODULE,
 839         .open           = profile_open,
 840         .read           = seq_read,
 841         .llseek         = seq_lseek,
 842         .release        = seq_release,
 843 };
 844
 845 /* Kprobe handler */
 846 static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
 847 {
 848         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
 849         struct kprobe_trace_entry *entry;
 850         struct ring_buffer_event *event;
 851         struct ring_buffer *buffer;
 852         int size, i, pc;
 853         unsigned long irq_flags;
 854         struct ftrace_event_call *call = &tp->call;
 855
 856         tp->nhit++;
 857
 858         local_save_flags(irq_flags);
 859         pc = preempt_count();
 860
 861         size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);
 862
 863         event = trace_current_buffer_lock_reserve(&buffer, call->id, size,
 864                                                   irq_flags, pc);
 865         if (!event)
 866                 return 0;
 867
 868         entry = ring_buffer_event_data(event);
 869         entry->nargs = tp->nr_args;
 870         entry->ip = (unsigned long)kp->addr;
 871         for (i = 0; i < tp->nr_args; i++)
 872                 entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
 873
 874         if (!filter_current_check_discard(buffer, call, entry, event))
 875                 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
 876         return 0;
 877 }
 878
 879 /* Kretprobe handler */
 880 static __kprobes int kretprobe_trace_func(struct kretprobe_instance *ri,
 881                                           struct pt_regs *regs)
 882 {
 883         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
 884         struct kretprobe_trace_entry *entry;
 885         struct ring_buffer_event *event;
 886         struct ring_buffer *buffer;
 887         int size, i, pc;
 888         unsigned long irq_flags;
 889         struct ftrace_event_call *call = &tp->call;
 890
 891         local_save_flags(irq_flags);
 892         pc = preempt_count();
 893
 894         size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);
 895
 896         event = trace_current_buffer_lock_reserve(&buffer, call->id, size,
 897                                                   irq_flags, pc);
 898         if (!event)
 899                 return 0;
 900
 901         entry = ring_buffer_event_data(event);
 902         entry->nargs = tp->nr_args;
 903         entry->func = (unsigned long)tp->rp.kp.addr;
 904         entry->ret_ip = (unsigned long)ri->ret_addr;
 905         for (i = 0; i < tp->nr_args; i++)
 906                 entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
 907
 908         if (!filter_current_check_discard(buffer, call, entry, event))
 909                 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
 910
 911         return 0;
 912 }
 913
 914 /* Event entry printers */
 915 enum print_line_t
 916 print_kprobe_event(struct trace_iterator *iter, int flags)
 917 {
 918         struct kprobe_trace_entry *field;
 919         struct trace_seq *s = &iter->seq;
 920         struct trace_event *event;
 921         struct trace_probe *tp;
 922         int i;
 923
 924         field = (struct kprobe_trace_entry *)iter->ent;
 925         event = ftrace_find_event(field->ent.type);
 926         tp = container_of(event, struct trace_probe, event);
 927
 928         if (!trace_seq_printf(s, "%s: (", tp->call.name))
 929                 goto partial;
 930
 931         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
 932                 goto partial;
 933
 934         if (!trace_seq_puts(s, ")"))
 935                 goto partial;
 936
 937         for (i = 0; i < field->nargs; i++)
 938                 if (!trace_seq_printf(s, " %s=%lx",
 939                                       tp->args[i].name, field->args[i]))
 940                         goto partial;
 941
 942         if (!trace_seq_puts(s, "\n"))
 943                 goto partial;
 944
 945         return TRACE_TYPE_HANDLED;
 946 partial:
 947         return TRACE_TYPE_PARTIAL_LINE;
 948 }
 949
 950 enum print_line_t
 951 print_kretprobe_event(struct trace_iterator *iter, int flags)
 952 {
 953         struct kretprobe_trace_entry *field;
 954         struct trace_seq *s = &iter->seq;
 955         struct trace_event *event;
 956         struct trace_probe *tp;
 957         int i;
 958
 959         field = (struct kretprobe_trace_entry *)iter->ent;
 960         event = ftrace_find_event(field->ent.type);
 961         tp = container_of(event, struct trace_probe, event);
 962
 963         if (!trace_seq_printf(s, "%s: (", tp->call.name))
 964                 goto partial;
 965
 966         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
 967                 goto partial;
 968
 969         if (!trace_seq_puts(s, " <- "))
 970                 goto partial;
 971
 972         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
 973                 goto partial;
 974
 975         if (!trace_seq_puts(s, ")"))
 976                 goto partial;
 977
 978         for (i = 0; i < field->nargs; i++)
 979                 if (!trace_seq_printf(s, " %s=%lx",
 980                                       tp->args[i].name, field->args[i]))
 981                         goto partial;
 982
 983         if (!trace_seq_puts(s, "\n"))
 984                 goto partial;
 985
 986         return TRACE_TYPE_HANDLED;
 987 partial:
 988         return TRACE_TYPE_PARTIAL_LINE;
 989 }
 990
 991 static int probe_event_enable(struct ftrace_event_call *call)
 992 {
 993         struct trace_probe *tp = (struct trace_probe *)call->data;
 994
 995         tp->flags |= TP_FLAG_TRACE;
 996         if (probe_is_return(tp))
 997                 return enable_kretprobe(&tp->rp);
 998         else
 999                 return enable_kprobe(&tp->rp.kp);
1000 }
1001
1002 static void probe_event_disable(struct ftrace_event_call *call)
1003 {
1004         struct trace_probe *tp = (struct trace_probe *)call->data;
1005
1006         tp->flags &= ~TP_FLAG_TRACE;
1007         if (!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE))) {
1008                 if (probe_is_return(tp))
1009                         disable_kretprobe(&tp->rp);
1010                 else
1011                         disable_kprobe(&tp->rp.kp);
1012         }
1013 }
1014
1015 static int probe_event_raw_init(struct ftrace_event_call *event_call)
1016 {
1017         INIT_LIST_HEAD(&event_call->fields);
1018
1019         return 0;
1020 }
1021
1022 #undef DEFINE_FIELD
1023 #define DEFINE_FIELD(type, item, name, is_signed)                       \
1024         do {                                                            \
1025                 ret = trace_define_field(event_call, #type, name,       \
1026                                          offsetof(typeof(field), item), \
1027                                          sizeof(field.item), is_signed, \
1028                                          FILTER_OTHER);                 \
1029                 if (ret)                                                \
1030                         return ret;                                     \
1031         } while (0)
1032
1033 static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1034 {
1035         int ret, i;
1036         struct kprobe_trace_entry field;
1037         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1038
1039         ret = trace_define_common_fields(event_call);
1040         if (!ret)
1041                 return ret;
1042
1043         DEFINE_FIELD(unsigned long, ip, "ip", 0);
1044         DEFINE_FIELD(int, nargs, "nargs", 1);
1045         /* Set argument names as fields */
1046         for (i = 0; i < tp->nr_args; i++)
1047                 DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
1048         return 0;
1049 }
1050
1051 static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1052 {
1053         int ret, i;
1054         struct kretprobe_trace_entry field;
1055         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1056
1057         ret = trace_define_common_fields(event_call);
1058         if (!ret)
1059                 return ret;
1060
1061         DEFINE_FIELD(unsigned long, func, "func", 0);
1062         DEFINE_FIELD(unsigned long, ret_ip, "ret_ip", 0);
1063         DEFINE_FIELD(int, nargs, "nargs", 1);
1064         /* Set argument names as fields */
1065         for (i = 0; i < tp->nr_args; i++)
1066                 DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
1067         return 0;
1068 }
1069
1070 static int __probe_event_show_format(struct trace_seq *s,
1071                                      struct trace_probe *tp, const char *fmt,
1072                                      const char *arg)
1073 {
1074         int i;
1075
1076         /* Show format */
1077         if (!trace_seq_printf(s, "\nprint fmt: \"%s", fmt))
1078                 return 0;
1079
1080         for (i = 0; i < tp->nr_args; i++)
1081                 if (!trace_seq_printf(s, " %s=%%lx", tp->args[i].name))
1082                         return 0;
1083
1084         if (!trace_seq_printf(s, "\", %s", arg))
1085                 return 0;
1086
1087         for (i = 0; i < tp->nr_args; i++)
1088                 if (!trace_seq_printf(s, ", REC->%s", tp->args[i].name))
1089                         return 0;
1090
1091         return trace_seq_puts(s, "\n");
1092 }
1093
1094 #undef SHOW_FIELD
1095 #define SHOW_FIELD(type, item, name)                                    \
1096         do {                                                            \
1097                 ret = trace_seq_printf(s, "\tfield: " #type " %s;\t"    \
1098                                 "offset:%u;\tsize:%u;\n", name,         \
1099                                 (unsigned int)offsetof(typeof(field), item),\
1100                                 (unsigned int)sizeof(type));            \
1101                 if (!ret)                                               \
1102                         return 0;                                       \
1103         } while (0)
1104
1105 static int kprobe_event_show_format(struct ftrace_event_call *call,
1106                                     struct trace_seq *s)
1107 {
1108         struct kprobe_trace_entry field __attribute__((unused));
1109         int ret, i;
1110         struct trace_probe *tp = (struct trace_probe *)call->data;
1111
1112         SHOW_FIELD(unsigned long, ip, "ip");
1113         SHOW_FIELD(int, nargs, "nargs");
1114
1115         /* Show fields */
1116         for (i = 0; i < tp->nr_args; i++)
1117                 SHOW_FIELD(unsigned long, args[i], tp->args[i].name);
1118         trace_seq_puts(s, "\n");
1119
1120         return __probe_event_show_format(s, tp, "(%lx)", "REC->ip");
1121 }
1122
1123 static int kretprobe_event_show_format(struct ftrace_event_call *call,
1124                                        struct trace_seq *s)
1125 {
1126         struct kretprobe_trace_entry field __attribute__((unused));
1127         int ret, i;
1128         struct trace_probe *tp = (struct trace_probe *)call->data;
1129
1130         SHOW_FIELD(unsigned long, func, "func");
1131         SHOW_FIELD(unsigned long, ret_ip, "ret_ip");
1132         SHOW_FIELD(int, nargs, "nargs");
1133
1134         /* Show fields */
1135         for (i = 0; i < tp->nr_args; i++)
1136                 SHOW_FIELD(unsigned long, args[i], tp->args[i].name);
1137         trace_seq_puts(s, "\n");
1138
1139         return __probe_event_show_format(s, tp, "(%lx <- %lx)",
1140                                           "REC->func, REC->ret_ip");
1141 }
1142
1143 #ifdef CONFIG_EVENT_PROFILE
1144
1145 /* Kprobe profile handler */
1146 static __kprobes int kprobe_profile_func(struct kprobe *kp,
1147                                          struct pt_regs *regs)
1148 {
1149         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1150         struct ftrace_event_call *call = &tp->call;
1151         struct kprobe_trace_entry *entry;
1152         int size, __size, i, pc;
1153         unsigned long irq_flags;
1154
1155         local_save_flags(irq_flags);
1156         pc = preempt_count();
1157
1158         __size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);
1159         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1160         size -= sizeof(u32);
1161
1162         do {
1163                 char raw_data[size];
1164                 struct trace_entry *ent;
1165                 /*
1166                  * Zero dead bytes from alignment to avoid stack leak
1167                  * to userspace
1168                  */
1169                 *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
1170                 entry = (struct kprobe_trace_entry *)raw_data;
1171                 ent = &entry->ent;
1172
1173                 tracing_generic_entry_update(ent, irq_flags, pc);
1174                 ent->type = call->id;
1175                 entry->nargs = tp->nr_args;
1176                 entry->ip = (unsigned long)kp->addr;
1177                 for (i = 0; i < tp->nr_args; i++)
1178                         entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
1179                 perf_tp_event(call->id, entry->ip, 1, entry, size);
1180         } while (0);
1181         return 0;
1182 }
1183
1184 /* Kretprobe profile handler */
1185 static __kprobes int kretprobe_profile_func(struct kretprobe_instance *ri,
1186                                             struct pt_regs *regs)
1187 {
1188         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1189         struct ftrace_event_call *call = &tp->call;
1190         struct kretprobe_trace_entry *entry;
1191         int size, __size, i, pc;
1192         unsigned long irq_flags;
1193
1194         local_save_flags(irq_flags);
1195         pc = preempt_count();
1196
1197         __size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);
1198         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1199         size -= sizeof(u32);
1200
1201         do {
1202                 char raw_data[size];
1203                 struct trace_entry *ent;
1204
1205                 *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
1206                 entry = (struct kretprobe_trace_entry *)raw_data;
1207                 ent = &entry->ent;
1208
1209                 tracing_generic_entry_update(ent, irq_flags, pc);
1210                 ent->type = call->id;
1211                 entry->nargs = tp->nr_args;
1212                 entry->func = (unsigned long)tp->rp.kp.addr;
1213                 entry->ret_ip = (unsigned long)ri->ret_addr;
1214                 for (i = 0; i < tp->nr_args; i++)
1215                         entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
1216                 perf_tp_event(call->id, entry->ret_ip, 1, entry, size);
1217         } while (0);
1218         return 0;
1219 }
1220
1221 static int probe_profile_enable(struct ftrace_event_call *call)
1222 {
1223         struct trace_probe *tp = (struct trace_probe *)call->data;
1224
1225         tp->flags |= TP_FLAG_PROFILE;
1226
1227         if (probe_is_return(tp))
1228                 return enable_kretprobe(&tp->rp);
1229         else
1230                 return enable_kprobe(&tp->rp.kp);
1231 }
1232
1233 static void probe_profile_disable(struct ftrace_event_call *call)
1234 {
1235         struct trace_probe *tp = (struct trace_probe *)call->data;
1236
1237         tp->flags &= ~TP_FLAG_PROFILE;
1238
1239         if (!(tp->flags & TP_FLAG_TRACE)) {
1240                 if (probe_is_return(tp))
1241                         disable_kretprobe(&tp->rp);
1242                 else
1243                         disable_kprobe(&tp->rp.kp);
1244         }
1245 }
1246 #endif  /* CONFIG_EVENT_PROFILE */
1247
1248
1249 static __kprobes
1250 int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1251 {
1252         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1253
1254         if (tp->flags & TP_FLAG_TRACE)
1255                 kprobe_trace_func(kp, regs);
1256 #ifdef CONFIG_EVENT_PROFILE
1257         if (tp->flags & TP_FLAG_PROFILE)
1258                 kprobe_profile_func(kp, regs);
1259 #endif  /* CONFIG_EVENT_PROFILE */
1260         return 0;       /* We don't tweek kernel, so just return 0 */
1261 }
1262
1263 static __kprobes
1264 int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1265 {
1266         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1267
1268         if (tp->flags & TP_FLAG_TRACE)
1269                 kretprobe_trace_func(ri, regs);
1270 #ifdef CONFIG_EVENT_PROFILE
1271         if (tp->flags & TP_FLAG_PROFILE)
1272                 kretprobe_profile_func(ri, regs);
1273 #endif  /* CONFIG_EVENT_PROFILE */
1274         return 0;       /* We don't tweek kernel, so just return 0 */
1275 }
1276
1277 static int register_probe_event(struct trace_probe *tp)
1278 {
1279         struct ftrace_event_call *call = &tp->call;
1280         int ret;
1281
1282         /* Initialize ftrace_event_call */
1283         if (probe_is_return(tp)) {
1284                 tp->event.trace = print_kretprobe_event;
1285                 call->raw_init = probe_event_raw_init;
1286                 call->show_format = kretprobe_event_show_format;
1287                 call->define_fields = kretprobe_event_define_fields;
1288         } else {
1289                 tp->event.trace = print_kprobe_event;
1290                 call->raw_init = probe_event_raw_init;
1291                 call->show_format = kprobe_event_show_format;
1292                 call->define_fields = kprobe_event_define_fields;
1293         }
1294         call->event = &tp->event;
1295         call->id = register_ftrace_event(&tp->event);
1296         if (!call->id)
1297                 return -ENODEV;
1298         call->enabled = 0;
1299         call->regfunc = probe_event_enable;
1300         call->unregfunc = probe_event_disable;
1301
1302 #ifdef CONFIG_EVENT_PROFILE
1303         atomic_set(&call->profile_count, -1);
1304         call->profile_enable = probe_profile_enable;
1305         call->profile_disable = probe_profile_disable;
1306 #endif
1307         call->data = tp;
1308         ret = trace_add_event_call(call);
1309         if (ret) {
1310                 pr_info("Failed to register kprobe event: %s\n", call->name);
1311                 unregister_ftrace_event(&tp->event);
1312         }
1313         return ret;
1314 }
1315
1316 static void unregister_probe_event(struct trace_probe *tp)
1317 {
1318         /* tp->event is unregistered in trace_remove_event_call() */
1319         trace_remove_event_call(&tp->call);
1320 }
1321
1322 /* Make a debugfs interface for controling probe points */
1323 static __init int init_kprobe_trace(void)
1324 {
1325         struct dentry *d_tracer;
1326         struct dentry *entry;
1327
1328         d_tracer = tracing_init_dentry();
1329         if (!d_tracer)
1330                 return 0;
1331
1332         entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
1333                                     NULL, &kprobe_events_ops);
1334
1335         /* Event list interface */
1336         if (!entry)
1337                 pr_warning("Could not create debugfs "
1338                            "'kprobe_events' entry\n");
1339
1340         /* Profile interface */
1341         entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
1342                                     NULL, &kprobe_profile_ops);
1343
1344         if (!entry)
1345                 pr_warning("Could not create debugfs "
1346                            "'kprobe_profile' entry\n");
1347         return 0;
1348 }
1349 fs_initcall(init_kprobe_trace);
1350
1351
1352 #ifdef CONFIG_FTRACE_STARTUP_TEST
1353
1354 static int kprobe_trace_selftest_target(int a1, int a2, int a3,
1355                                         int a4, int a5, int a6)
1356 {
1357         return a1 + a2 + a3 + a4 + a5 + a6;
1358 }
1359
1360 static __init int kprobe_trace_self_tests_init(void)
1361 {
1362         int ret;
1363         int (*target)(int, int, int, int, int, int);
1364
1365         target = kprobe_trace_selftest_target;
1366
1367         pr_info("Testing kprobe tracing: ");
1368
1369         ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target "
1370                                   "a1 a2 a3 a4 a5 a6");
1371         if (WARN_ON_ONCE(ret))
1372                 pr_warning("error enabling function entry\n");
1373
1374         ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target "
1375                                   "ra rv");
1376         if (WARN_ON_ONCE(ret))
1377                 pr_warning("error enabling function return\n");
1378
1379         ret = target(1, 2, 3, 4, 5, 6);
1380
1381         cleanup_all_probes();
1382
1383         pr_cont("OK\n");
1384         return 0;
1385 }
1386
1387 late_initcall(kprobe_trace_self_tests_init);
1388
1389 #endif