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 /* Reserved field names */
  42 #define FIELD_STRING_IP "__probe_ip"
  43 #define FIELD_STRING_NARGS "__probe_nargs"
  44 #define FIELD_STRING_RETIP "__probe_ret_ip"
  45 #define FIELD_STRING_FUNC "__probe_func"
  46
  47 const char *reserved_field_names[] = {
  48         "common_type",
  49         "common_flags",
  50         "common_preempt_count",
  51         "common_pid",
  52         "common_tgid",
  53         "common_lock_depth",
  54         FIELD_STRING_IP,
  55         FIELD_STRING_NARGS,
  56         FIELD_STRING_RETIP,
  57         FIELD_STRING_FUNC,
  58 };
  59
  60 /* currently, trace_kprobe only supports X86. */
  61
  62 struct fetch_func {
  63         unsigned long (*func)(struct pt_regs *, void *);
  64         void *data;
  65 };
  66
  67 static __kprobes unsigned long call_fetch(struct fetch_func *f,
  68                                           struct pt_regs *regs)
  69 {
  70         return f->func(regs, f->data);
  71 }
  72
  73 /* fetch handlers */
  74 static __kprobes unsigned long fetch_register(struct pt_regs *regs,
  75                                               void *offset)
  76 {
  77         return regs_get_register(regs, (unsigned int)((unsigned long)offset));
  78 }
  79
  80 static __kprobes unsigned long fetch_stack(struct pt_regs *regs,
  81                                            void *num)
  82 {
  83         return regs_get_kernel_stack_nth(regs,
  84                                          (unsigned int)((unsigned long)num));
  85 }
  86
  87 static __kprobes unsigned long fetch_memory(struct pt_regs *regs, void *addr)
  88 {
  89         unsigned long retval;
  90
  91         if (probe_kernel_address(addr, retval))
  92                 return 0;
  93         return retval;
  94 }
  95
  96 static __kprobes unsigned long fetch_argument(struct pt_regs *regs, void *num)
  97 {
  98         return regs_get_argument_nth(regs, (unsigned int)((unsigned long)num));
  99 }
 100
 101 static __kprobes unsigned long fetch_retvalue(struct pt_regs *regs,
 102                                               void *dummy)
 103 {
 104         return regs_return_value(regs);
 105 }
 106
 107 static __kprobes unsigned long fetch_stack_address(struct pt_regs *regs,
 108                                                    void *dummy)
 109 {
 110         return kernel_stack_pointer(regs);
 111 }
 112
 113 /* Memory fetching by symbol */
 114 struct symbol_cache {
 115         char *symbol;
 116         long offset;
 117         unsigned long addr;
 118 };
 119
 120 static unsigned long update_symbol_cache(struct symbol_cache *sc)
 121 {
 122         sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
 123         if (sc->addr)
 124                 sc->addr += sc->offset;
 125         return sc->addr;
 126 }
 127
 128 static void free_symbol_cache(struct symbol_cache *sc)
 129 {
 130         kfree(sc->symbol);
 131         kfree(sc);
 132 }
 133
 134 static struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
 135 {
 136         struct symbol_cache *sc;
 137
 138         if (!sym || strlen(sym) == 0)
 139                 return NULL;
 140         sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
 141         if (!sc)
 142                 return NULL;
 143
 144         sc->symbol = kstrdup(sym, GFP_KERNEL);
 145         if (!sc->symbol) {
 146                 kfree(sc);
 147                 return NULL;
 148         }
 149         sc->offset = offset;
 150
 151         update_symbol_cache(sc);
 152         return sc;
 153 }
 154
 155 static __kprobes unsigned long fetch_symbol(struct pt_regs *regs, void *data)
 156 {
 157         struct symbol_cache *sc = data;
 158
 159         if (sc->addr)
 160                 return fetch_memory(regs, (void *)sc->addr);
 161         else
 162                 return 0;
 163 }
 164
 165 /* Special indirect memory access interface */
 166 struct indirect_fetch_data {
 167         struct fetch_func orig;
 168         long offset;
 169 };
 170
 171 static __kprobes unsigned long fetch_indirect(struct pt_regs *regs, void *data)
 172 {
 173         struct indirect_fetch_data *ind = data;
 174         unsigned long addr;
 175
 176         addr = call_fetch(&ind->orig, regs);
 177         if (addr) {
 178                 addr += ind->offset;
 179                 return fetch_memory(regs, (void *)addr);
 180         } else
 181                 return 0;
 182 }
 183
 184 static __kprobes void free_indirect_fetch_data(struct indirect_fetch_data *data)
 185 {
 186         if (data->orig.func == fetch_indirect)
 187                 free_indirect_fetch_data(data->orig.data);
 188         else if (data->orig.func == fetch_symbol)
 189                 free_symbol_cache(data->orig.data);
 190         kfree(data);
 191 }
 192
 193 /**
 194  * Kprobe tracer core functions
 195  */
 196
 197 struct probe_arg {
 198         struct fetch_func       fetch;
 199         const char              *name;
 200 };
 201
 202 /* Flags for trace_probe */
 203 #define TP_FLAG_TRACE   1
 204 #define TP_FLAG_PROFILE 2
 205
 206 struct trace_probe {
 207         struct list_head        list;
 208         struct kretprobe        rp;     /* Use rp.kp for kprobe use */
 209         unsigned long           nhit;
 210         unsigned int            flags;  /* For TP_FLAG_* */
 211         const char              *symbol;        /* symbol name */
 212         struct ftrace_event_call        call;
 213         struct trace_event              event;
 214         unsigned int            nr_args;
 215         struct probe_arg        args[];
 216 };
 217
 218 #define SIZEOF_TRACE_PROBE(n)                   \
 219         (offsetof(struct trace_probe, args) +   \
 220         (sizeof(struct probe_arg) * (n)))
 221
 222 static __kprobes int probe_is_return(struct trace_probe *tp)
 223 {
 224         return tp->rp.handler != NULL;
 225 }
 226
 227 static __kprobes const char *probe_symbol(struct trace_probe *tp)
 228 {
 229         return tp->symbol ? tp->symbol : "unknown";
 230 }
 231
 232 static int probe_arg_string(char *buf, size_t n, struct fetch_func *ff)
 233 {
 234         int ret = -EINVAL;
 235
 236         if (ff->func == fetch_argument)
 237                 ret = snprintf(buf, n, "$arg%lu", (unsigned long)ff->data);
 238         else if (ff->func == fetch_register) {
 239                 const char *name;
 240                 name = regs_query_register_name((unsigned int)((long)ff->data));
 241                 ret = snprintf(buf, n, "%%%s", name);
 242         } else if (ff->func == fetch_stack)
 243                 ret = snprintf(buf, n, "$stack%lu", (unsigned long)ff->data);
 244         else if (ff->func == fetch_memory)
 245                 ret = snprintf(buf, n, "@0x%p", ff->data);
 246         else if (ff->func == fetch_symbol) {
 247                 struct symbol_cache *sc = ff->data;
 248                 ret = snprintf(buf, n, "@%s%+ld", sc->symbol, sc->offset);
 249         } else if (ff->func == fetch_retvalue)
 250                 ret = snprintf(buf, n, "$retval");
 251         else if (ff->func == fetch_stack_address)
 252                 ret = snprintf(buf, n, "$stack");
 253         else if (ff->func == fetch_indirect) {
 254                 struct indirect_fetch_data *id = ff->data;
 255                 size_t l = 0;
 256                 ret = snprintf(buf, n, "%+ld(", id->offset);
 257                 if (ret >= n)
 258                         goto end;
 259                 l += ret;
 260                 ret = probe_arg_string(buf + l, n - l, &id->orig);
 261                 if (ret < 0)
 262                         goto end;
 263                 l += ret;
 264                 ret = snprintf(buf + l, n - l, ")");
 265                 ret += l;
 266         }
 267 end:
 268         if (ret >= n)
 269                 return -ENOSPC;
 270         return ret;
 271 }
 272
 273 static int register_probe_event(struct trace_probe *tp);
 274 static void unregister_probe_event(struct trace_probe *tp);
 275
 276 static DEFINE_MUTEX(probe_lock);
 277 static LIST_HEAD(probe_list);
 278
 279 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
 280 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
 281                                 struct pt_regs *regs);
 282
 283 /*
 284  * Allocate new trace_probe and initialize it (including kprobes).
 285  */
 286 static struct trace_probe *alloc_trace_probe(const char *group,
 287                                              const char *event,
 288                                              void *addr,
 289                                              const char *symbol,
 290                                              unsigned long offs,
 291                                              int nargs, int is_return)
 292 {
 293         struct trace_probe *tp;
 294
 295         tp = kzalloc(SIZEOF_TRACE_PROBE(nargs), GFP_KERNEL);
 296         if (!tp)
 297                 return ERR_PTR(-ENOMEM);
 298
 299         if (symbol) {
 300                 tp->symbol = kstrdup(symbol, GFP_KERNEL);
 301                 if (!tp->symbol)
 302                         goto error;
 303                 tp->rp.kp.symbol_name = tp->symbol;
 304                 tp->rp.kp.offset = offs;
 305         } else
 306                 tp->rp.kp.addr = addr;
 307
 308         if (is_return)
 309                 tp->rp.handler = kretprobe_dispatcher;
 310         else
 311                 tp->rp.kp.pre_handler = kprobe_dispatcher;
 312
 313         if (!event)
 314                 goto error;
 315         tp->call.name = kstrdup(event, GFP_KERNEL);
 316         if (!tp->call.name)
 317                 goto error;
 318
 319         if (!group)
 320                 goto error;
 321         tp->call.system = kstrdup(group, GFP_KERNEL);
 322         if (!tp->call.system)
 323                 goto error;
 324
 325         INIT_LIST_HEAD(&tp->list);
 326         return tp;
 327 error:
 328         kfree(tp->call.name);
 329         kfree(tp->symbol);
 330         kfree(tp);
 331         return ERR_PTR(-ENOMEM);
 332 }
 333
 334 static void free_probe_arg(struct probe_arg *arg)
 335 {
 336         if (arg->fetch.func == fetch_symbol)
 337                 free_symbol_cache(arg->fetch.data);
 338         else if (arg->fetch.func == fetch_indirect)
 339                 free_indirect_fetch_data(arg->fetch.data);
 340         kfree(arg->name);
 341 }
 342
 343 static void free_trace_probe(struct trace_probe *tp)
 344 {
 345         int i;
 346
 347         for (i = 0; i < tp->nr_args; i++)
 348                 free_probe_arg(&tp->args[i]);
 349
 350         kfree(tp->call.system);
 351         kfree(tp->call.name);
 352         kfree(tp->symbol);
 353         kfree(tp);
 354 }
 355
 356 static struct trace_probe *find_probe_event(const char *event)
 357 {
 358         struct trace_probe *tp;
 359
 360         list_for_each_entry(tp, &probe_list, list)
 361                 if (!strcmp(tp->call.name, event))
 362                         return tp;
 363         return NULL;
 364 }
 365
 366 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
 367 static void unregister_trace_probe(struct trace_probe *tp)
 368 {
 369         if (probe_is_return(tp))
 370                 unregister_kretprobe(&tp->rp);
 371         else
 372                 unregister_kprobe(&tp->rp.kp);
 373         list_del(&tp->list);
 374         unregister_probe_event(tp);
 375 }
 376
 377 /* Register a trace_probe and probe_event */
 378 static int register_trace_probe(struct trace_probe *tp)
 379 {
 380         struct trace_probe *old_tp;
 381         int ret;
 382
 383         mutex_lock(&probe_lock);
 384
 385         /* register as an event */
 386         old_tp = find_probe_event(tp->call.name);
 387         if (old_tp) {
 388                 /* delete old event */
 389                 unregister_trace_probe(old_tp);
 390                 free_trace_probe(old_tp);
 391         }
 392         ret = register_probe_event(tp);
 393         if (ret) {
 394                 pr_warning("Faild to register probe event(%d)\n", ret);
 395                 goto end;
 396         }
 397
 398         tp->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 399         if (probe_is_return(tp))
 400                 ret = register_kretprobe(&tp->rp);
 401         else
 402                 ret = register_kprobe(&tp->rp.kp);
 403
 404         if (ret) {
 405                 pr_warning("Could not insert probe(%d)\n", ret);
 406                 if (ret == -EILSEQ) {
 407                         pr_warning("Probing address(0x%p) is not an "
 408                                    "instruction boundary.\n",
 409                                    tp->rp.kp.addr);
 410                         ret = -EINVAL;
 411                 }
 412                 unregister_probe_event(tp);
 413         } else
 414                 list_add_tail(&tp->list, &probe_list);
 415 end:
 416         mutex_unlock(&probe_lock);
 417         return ret;
 418 }
 419
 420 /* Split symbol and offset. */
 421 static int split_symbol_offset(char *symbol, unsigned long *offset)
 422 {
 423         char *tmp;
 424         int ret;
 425
 426         if (!offset)
 427                 return -EINVAL;
 428
 429         tmp = strchr(symbol, '+');
 430         if (tmp) {
 431                 /* skip sign because strict_strtol doesn't accept '+' */
 432                 ret = strict_strtoul(tmp + 1, 0, offset);
 433                 if (ret)
 434                         return ret;
 435                 *tmp = '\0';
 436         } else
 437                 *offset = 0;
 438         return 0;
 439 }
 440
 441 #define PARAM_MAX_ARGS 16
 442 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
 443
 444 static int parse_probe_vars(char *arg, struct fetch_func *ff, int is_return)
 445 {
 446         int ret = 0;
 447         unsigned long param;
 448
 449         if (strcmp(arg, "retval") == 0) {
 450                 if (is_return) {
 451                         ff->func = fetch_retvalue;
 452                         ff->data = NULL;
 453                 } else
 454                         ret = -EINVAL;
 455         } else if (strncmp(arg, "stack", 5) == 0) {
 456                 if (arg[5] == '\0') {
 457                         ff->func = fetch_stack_address;
 458                         ff->data = NULL;
 459                 } else if (isdigit(arg[5])) {
 460                         ret = strict_strtoul(arg + 5, 10, &param);
 461                         if (ret || param > PARAM_MAX_STACK)
 462                                 ret = -EINVAL;
 463                         else {
 464                                 ff->func = fetch_stack;
 465                                 ff->data = (void *)param;
 466                         }
 467                 } else
 468                         ret = -EINVAL;
 469         } else if (strncmp(arg, "arg", 3) == 0 && isdigit(arg[3])) {
 470                 ret = strict_strtoul(arg + 3, 10, &param);
 471                 if (ret || param > PARAM_MAX_ARGS)
 472                         ret = -EINVAL;
 473                 else {
 474                         ff->func = fetch_argument;
 475                         ff->data = (void *)param;
 476                 }
 477         } else
 478                 ret = -EINVAL;
 479         return ret;
 480 }
 481
 482 static int parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
 483 {
 484         int ret = 0;
 485         unsigned long param;
 486         long offset;
 487         char *tmp;
 488
 489         switch (arg[0]) {
 490         case '$':
 491                 ret = parse_probe_vars(arg + 1, ff, is_return);
 492                 break;
 493         case '%':       /* named register */
 494                 ret = regs_query_register_offset(arg + 1);
 495                 if (ret >= 0) {
 496                         ff->func = fetch_register;
 497                         ff->data = (void *)(unsigned long)ret;
 498                         ret = 0;
 499                 }
 500                 break;
 501         case '@':       /* memory or symbol */
 502                 if (isdigit(arg[1])) {
 503                         ret = strict_strtoul(arg + 1, 0, &param);
 504                         if (ret)
 505                                 break;
 506                         ff->func = fetch_memory;
 507                         ff->data = (void *)param;
 508                 } else {
 509                         ret = split_symbol_offset(arg + 1, &offset);
 510                         if (ret)
 511                                 break;
 512                         ff->data = alloc_symbol_cache(arg + 1, offset);
 513                         if (ff->data)
 514                                 ff->func = fetch_symbol;
 515                         else
 516                                 ret = -EINVAL;
 517                 }
 518                 break;
 519         case '+':       /* indirect memory */
 520         case '-':
 521                 tmp = strchr(arg, '(');
 522                 if (!tmp) {
 523                         ret = -EINVAL;
 524                         break;
 525                 }
 526                 *tmp = '\0';
 527                 ret = strict_strtol(arg + 1, 0, &offset);
 528                 if (ret)
 529                         break;
 530                 if (arg[0] == '-')
 531                         offset = -offset;
 532                 arg = tmp + 1;
 533                 tmp = strrchr(arg, ')');
 534                 if (tmp) {
 535                         struct indirect_fetch_data *id;
 536                         *tmp = '\0';
 537                         id = kzalloc(sizeof(struct indirect_fetch_data),
 538                                      GFP_KERNEL);
 539                         if (!id)
 540                                 return -ENOMEM;
 541                         id->offset = offset;
 542                         ret = parse_probe_arg(arg, &id->orig, is_return);
 543                         if (ret)
 544                                 kfree(id);
 545                         else {
 546                                 ff->func = fetch_indirect;
 547                                 ff->data = (void *)id;
 548                         }
 549                 } else
 550                         ret = -EINVAL;
 551                 break;
 552         default:
 553                 /* TODO: support custom handler */
 554                 ret = -EINVAL;
 555         }
 556         return ret;
 557 }
 558
 559 /* Return 1 if name is reserved or already used by another argument */
 560 static int conflict_field_name(const char *name,
 561                                struct probe_arg *args, int narg)
 562 {
 563         int i;
 564         for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
 565                 if (strcmp(reserved_field_names[i], name) == 0)
 566                         return 1;
 567         for (i = 0; i < narg; i++)
 568                 if (strcmp(args[i].name, name) == 0)
 569                         return 1;
 570         return 0;
 571 }
 572
 573 static int create_trace_probe(int argc, char **argv)
 574 {
 575         /*
 576          * Argument syntax:
 577          *  - Add kprobe: p[:[GRP/]EVENT] KSYM[+OFFS]|KADDR [FETCHARGS]
 578          *  - Add kretprobe: r[:[GRP/]EVENT] KSYM[+0] [FETCHARGS]
 579          * Fetch args:
 580          *  $argN       : fetch Nth of function argument. (N:0-)
 581          *  $retval     : fetch return value
 582          *  $stack      : fetch stack address
 583          *  $stackN     : fetch Nth of stack (N:0-)
 584          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 585          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 586          *  %REG        : fetch register REG
 587          * Indirect memory fetch:
 588          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 589          * Alias name of args:
 590          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 591          */
 592         struct trace_probe *tp;
 593         int i, ret = 0;
 594         int is_return = 0;
 595         char *symbol = NULL, *event = NULL, *arg = NULL, *group = NULL;
 596         unsigned long offset = 0;
 597         void *addr = NULL;
 598         char buf[MAX_EVENT_NAME_LEN];
 599
 600         if (argc < 2)
 601                 return -EINVAL;
 602
 603         if (argv[0][0] == 'p')
 604                 is_return = 0;
 605         else if (argv[0][0] == 'r')
 606                 is_return = 1;
 607         else
 608                 return -EINVAL;
 609
 610         if (argv[0][1] == ':') {
 611                 event = &argv[0][2];
 612                 if (strchr(event, '/')) {
 613                         group = event;
 614                         event = strchr(group, '/') + 1;
 615                         event[-1] = '\0';
 616                         if (strlen(group) == 0) {
 617                                 pr_info("Group name is not specifiled\n");
 618                                 return -EINVAL;
 619                         }
 620                 }
 621                 if (strlen(event) == 0) {
 622                         pr_info("Event name is not specifiled\n");
 623                         return -EINVAL;
 624                 }
 625         }
 626
 627         if (isdigit(argv[1][0])) {
 628                 if (is_return)
 629                         return -EINVAL;
 630                 /* an address specified */
 631                 ret = strict_strtoul(&argv[0][2], 0, (unsigned long *)&addr);
 632                 if (ret)
 633                         return ret;
 634         } else {
 635                 /* a symbol specified */
 636                 symbol = argv[1];
 637                 /* TODO: support .init module functions */
 638                 ret = split_symbol_offset(symbol, &offset);
 639                 if (ret)
 640                         return ret;
 641                 if (offset && is_return)
 642                         return -EINVAL;
 643         }
 644         argc -= 2; argv += 2;
 645
 646         /* setup a probe */
 647         if (!group)
 648                 group = KPROBE_EVENT_SYSTEM;
 649         if (!event) {
 650                 /* Make a new event name */
 651                 if (symbol)
 652                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c@%s%+ld",
 653                                  is_return ? 'r' : 'p', symbol, offset);
 654                 else
 655                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c@0x%p",
 656                                  is_return ? 'r' : 'p', addr);
 657                 event = buf;
 658         }
 659         tp = alloc_trace_probe(group, event, addr, symbol, offset, argc,
 660                                is_return);
 661         if (IS_ERR(tp))
 662                 return PTR_ERR(tp);
 663
 664         /* parse arguments */
 665         ret = 0;
 666         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 667                 /* Parse argument name */
 668                 arg = strchr(argv[i], '=');
 669                 if (arg)
 670                         *arg++ = '\0';
 671                 else
 672                         arg = argv[i];
 673
 674                 if (conflict_field_name(argv[i], tp->args, i)) {
 675                         ret = -EINVAL;
 676                         goto error;
 677                 }
 678
 679                 tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
 680
 681                 /* Parse fetch argument */
 682                 if (strlen(arg) > MAX_ARGSTR_LEN) {
 683                         pr_info("Argument%d(%s) is too long.\n", i, arg);
 684                         ret = -ENOSPC;
 685                         goto error;
 686                 }
 687                 ret = parse_probe_arg(arg, &tp->args[i].fetch, is_return);
 688                 if (ret)
 689                         goto error;
 690         }
 691         tp->nr_args = i;
 692
 693         ret = register_trace_probe(tp);
 694         if (ret)
 695                 goto error;
 696         return 0;
 697
 698 error:
 699         free_trace_probe(tp);
 700         return ret;
 701 }
 702
 703 static void cleanup_all_probes(void)
 704 {
 705         struct trace_probe *tp;
 706
 707         mutex_lock(&probe_lock);
 708         /* TODO: Use batch unregistration */
 709         while (!list_empty(&probe_list)) {
 710                 tp = list_entry(probe_list.next, struct trace_probe, list);
 711                 unregister_trace_probe(tp);
 712                 free_trace_probe(tp);
 713         }
 714         mutex_unlock(&probe_lock);
 715 }
 716
 717
 718 /* Probes listing interfaces */
 719 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
 720 {
 721         mutex_lock(&probe_lock);
 722         return seq_list_start(&probe_list, *pos);
 723 }
 724
 725 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
 726 {
 727         return seq_list_next(v, &probe_list, pos);
 728 }
 729
 730 static void probes_seq_stop(struct seq_file *m, void *v)
 731 {
 732         mutex_unlock(&probe_lock);
 733 }
 734
 735 static int probes_seq_show(struct seq_file *m, void *v)
 736 {
 737         struct trace_probe *tp = v;
 738         int i, ret;
 739         char buf[MAX_ARGSTR_LEN + 1];
 740
 741         seq_printf(m, "%c", probe_is_return(tp) ? 'r' : 'p');
 742         seq_printf(m, ":%s", tp->call.name);
 743
 744         if (tp->symbol)
 745                 seq_printf(m, " %s+%u", probe_symbol(tp), tp->rp.kp.offset);
 746         else
 747                 seq_printf(m, " 0x%p", tp->rp.kp.addr);
 748
 749         for (i = 0; i < tp->nr_args; i++) {
 750                 ret = probe_arg_string(buf, MAX_ARGSTR_LEN, &tp->args[i].fetch);
 751                 if (ret < 0) {
 752                         pr_warning("Argument%d decoding error(%d).\n", i, ret);
 753                         return ret;
 754                 }
 755                 seq_printf(m, " %s=%s", tp->args[i].name, buf);
 756         }
 757         seq_printf(m, "\n");
 758         return 0;
 759 }
 760
 761 static const struct seq_operations probes_seq_op = {
 762         .start  = probes_seq_start,
 763         .next   = probes_seq_next,
 764         .stop   = probes_seq_stop,
 765         .show   = probes_seq_show
 766 };
 767
 768 static int probes_open(struct inode *inode, struct file *file)
 769 {
 770         if ((file->f_mode & FMODE_WRITE) &&
 771             (file->f_flags & O_TRUNC))
 772                 cleanup_all_probes();
 773
 774         return seq_open(file, &probes_seq_op);
 775 }
 776
 777 static int command_trace_probe(const char *buf)
 778 {
 779         char **argv;
 780         int argc = 0, ret = 0;
 781
 782         argv = argv_split(GFP_KERNEL, buf, &argc);
 783         if (!argv)
 784                 return -ENOMEM;
 785
 786         if (argc)
 787                 ret = create_trace_probe(argc, argv);
 788
 789         argv_free(argv);
 790         return ret;
 791 }
 792
 793 #define WRITE_BUFSIZE 128
 794
 795 static ssize_t probes_write(struct file *file, const char __user *buffer,
 796                             size_t count, loff_t *ppos)
 797 {
 798         char *kbuf, *tmp;
 799         int ret;
 800         size_t done;
 801         size_t size;
 802
 803         kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
 804         if (!kbuf)
 805                 return -ENOMEM;
 806
 807         ret = done = 0;
 808         while (done < count) {
 809                 size = count - done;
 810                 if (size >= WRITE_BUFSIZE)
 811                         size = WRITE_BUFSIZE - 1;
 812                 if (copy_from_user(kbuf, buffer + done, size)) {
 813                         ret = -EFAULT;
 814                         goto out;
 815                 }
 816                 kbuf[size] = '\0';
 817                 tmp = strchr(kbuf, '\n');
 818                 if (tmp) {
 819                         *tmp = '\0';
 820                         size = tmp - kbuf + 1;
 821                 } else if (done + size < count) {
 822                         pr_warning("Line length is too long: "
 823                                    "Should be less than %d.", WRITE_BUFSIZE);
 824                         ret = -EINVAL;
 825                         goto out;
 826                 }
 827                 done += size;
 828                 /* Remove comments */
 829                 tmp = strchr(kbuf, '#');
 830                 if (tmp)
 831                         *tmp = '\0';
 832
 833                 ret = command_trace_probe(kbuf);
 834                 if (ret)
 835                         goto out;
 836         }
 837         ret = done;
 838 out:
 839         kfree(kbuf);
 840         return ret;
 841 }
 842
 843 static const struct file_operations kprobe_events_ops = {
 844         .owner          = THIS_MODULE,
 845         .open           = probes_open,
 846         .read           = seq_read,
 847         .llseek         = seq_lseek,
 848         .release        = seq_release,
 849         .write          = probes_write,
 850 };
 851
 852 /* Probes profiling interfaces */
 853 static int probes_profile_seq_show(struct seq_file *m, void *v)
 854 {
 855         struct trace_probe *tp = v;
 856
 857         seq_printf(m, "  %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
 858                    tp->rp.kp.nmissed);
 859
 860         return 0;
 861 }
 862
 863 static const struct seq_operations profile_seq_op = {
 864         .start  = probes_seq_start,
 865         .next   = probes_seq_next,
 866         .stop   = probes_seq_stop,
 867         .show   = probes_profile_seq_show
 868 };
 869
 870 static int profile_open(struct inode *inode, struct file *file)
 871 {
 872         return seq_open(file, &profile_seq_op);
 873 }
 874
 875 static const struct file_operations kprobe_profile_ops = {
 876         .owner          = THIS_MODULE,
 877         .open           = profile_open,
 878         .read           = seq_read,
 879         .llseek         = seq_lseek,
 880         .release        = seq_release,
 881 };
 882
 883 /* Kprobe handler */
 884 static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
 885 {
 886         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
 887         struct kprobe_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         tp->nhit++;
 895
 896         local_save_flags(irq_flags);
 897         pc = preempt_count();
 898
 899         size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);
 900
 901         event = trace_current_buffer_lock_reserve(&buffer, call->id, size,
 902                                                   irq_flags, pc);
 903         if (!event)
 904                 return 0;
 905
 906         entry = ring_buffer_event_data(event);
 907         entry->nargs = tp->nr_args;
 908         entry->ip = (unsigned long)kp->addr;
 909         for (i = 0; i < tp->nr_args; i++)
 910                 entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
 911
 912         if (!filter_current_check_discard(buffer, call, entry, event))
 913                 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
 914         return 0;
 915 }
 916
 917 /* Kretprobe handler */
 918 static __kprobes int kretprobe_trace_func(struct kretprobe_instance *ri,
 919                                           struct pt_regs *regs)
 920 {
 921         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
 922         struct kretprobe_trace_entry *entry;
 923         struct ring_buffer_event *event;
 924         struct ring_buffer *buffer;
 925         int size, i, pc;
 926         unsigned long irq_flags;
 927         struct ftrace_event_call *call = &tp->call;
 928
 929         local_save_flags(irq_flags);
 930         pc = preempt_count();
 931
 932         size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);
 933
 934         event = trace_current_buffer_lock_reserve(&buffer, call->id, size,
 935                                                   irq_flags, pc);
 936         if (!event)
 937                 return 0;
 938
 939         entry = ring_buffer_event_data(event);
 940         entry->nargs = tp->nr_args;
 941         entry->func = (unsigned long)tp->rp.kp.addr;
 942         entry->ret_ip = (unsigned long)ri->ret_addr;
 943         for (i = 0; i < tp->nr_args; i++)
 944                 entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
 945
 946         if (!filter_current_check_discard(buffer, call, entry, event))
 947                 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
 948
 949         return 0;
 950 }
 951
 952 /* Event entry printers */
 953 enum print_line_t
 954 print_kprobe_event(struct trace_iterator *iter, int flags)
 955 {
 956         struct kprobe_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 kprobe_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->ip, flags | TRACE_ITER_SYM_OFFSET))
 970                 goto partial;
 971
 972         if (!trace_seq_puts(s, ")"))
 973                 goto partial;
 974
 975         for (i = 0; i < field->nargs; i++)
 976                 if (!trace_seq_printf(s, " %s=%lx",
 977                                       tp->args[i].name, field->args[i]))
 978                         goto partial;
 979
 980         if (!trace_seq_puts(s, "\n"))
 981                 goto partial;
 982
 983         return TRACE_TYPE_HANDLED;
 984 partial:
 985         return TRACE_TYPE_PARTIAL_LINE;
 986 }
 987
 988 enum print_line_t
 989 print_kretprobe_event(struct trace_iterator *iter, int flags)
 990 {
 991         struct kretprobe_trace_entry *field;
 992         struct trace_seq *s = &iter->seq;
 993         struct trace_event *event;
 994         struct trace_probe *tp;
 995         int i;
 996
 997         field = (struct kretprobe_trace_entry *)iter->ent;
 998         event = ftrace_find_event(field->ent.type);
 999         tp = container_of(event, struct trace_probe, event);
1000
1001         if (!trace_seq_printf(s, "%s: (", tp->call.name))
1002                 goto partial;
1003
1004         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1005                 goto partial;
1006
1007         if (!trace_seq_puts(s, " <- "))
1008                 goto partial;
1009
1010         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1011                 goto partial;
1012
1013         if (!trace_seq_puts(s, ")"))
1014                 goto partial;
1015
1016         for (i = 0; i < field->nargs; i++)
1017                 if (!trace_seq_printf(s, " %s=%lx",
1018                                       tp->args[i].name, field->args[i]))
1019                         goto partial;
1020
1021         if (!trace_seq_puts(s, "\n"))
1022                 goto partial;
1023
1024         return TRACE_TYPE_HANDLED;
1025 partial:
1026         return TRACE_TYPE_PARTIAL_LINE;
1027 }
1028
1029 static int probe_event_enable(struct ftrace_event_call *call)
1030 {
1031         struct trace_probe *tp = (struct trace_probe *)call->data;
1032
1033         tp->flags |= TP_FLAG_TRACE;
1034         if (probe_is_return(tp))
1035                 return enable_kretprobe(&tp->rp);
1036         else
1037                 return enable_kprobe(&tp->rp.kp);
1038 }
1039
1040 static void probe_event_disable(struct ftrace_event_call *call)
1041 {
1042         struct trace_probe *tp = (struct trace_probe *)call->data;
1043
1044         tp->flags &= ~TP_FLAG_TRACE;
1045         if (!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE))) {
1046                 if (probe_is_return(tp))
1047                         disable_kretprobe(&tp->rp);
1048                 else
1049                         disable_kprobe(&tp->rp.kp);
1050         }
1051 }
1052
1053 static int probe_event_raw_init(struct ftrace_event_call *event_call)
1054 {
1055         INIT_LIST_HEAD(&event_call->fields);
1056
1057         return 0;
1058 }
1059
1060 #undef DEFINE_FIELD
1061 #define DEFINE_FIELD(type, item, name, is_signed)                       \
1062         do {                                                            \
1063                 ret = trace_define_field(event_call, #type, name,       \
1064                                          offsetof(typeof(field), item), \
1065                                          sizeof(field.item), is_signed, \
1066                                          FILTER_OTHER);                 \
1067                 if (ret)                                                \
1068                         return ret;                                     \
1069         } while (0)
1070
1071 static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1072 {
1073         int ret, i;
1074         struct kprobe_trace_entry field;
1075         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1076
1077         ret = trace_define_common_fields(event_call);
1078         if (!ret)
1079                 return ret;
1080
1081         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1082         DEFINE_FIELD(int, nargs, FIELD_STRING_NARGS, 1);
1083         /* Set argument names as fields */
1084         for (i = 0; i < tp->nr_args; i++)
1085                 DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
1086         return 0;
1087 }
1088
1089 static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1090 {
1091         int ret, i;
1092         struct kretprobe_trace_entry field;
1093         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1094
1095         ret = trace_define_common_fields(event_call);
1096         if (!ret)
1097                 return ret;
1098
1099         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1100         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1101         DEFINE_FIELD(int, nargs, FIELD_STRING_NARGS, 1);
1102         /* Set argument names as fields */
1103         for (i = 0; i < tp->nr_args; i++)
1104                 DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
1105         return 0;
1106 }
1107
1108 static int __probe_event_show_format(struct trace_seq *s,
1109                                      struct trace_probe *tp, const char *fmt,
1110                                      const char *arg)
1111 {
1112         int i;
1113
1114         /* Show format */
1115         if (!trace_seq_printf(s, "\nprint fmt: \"%s", fmt))
1116                 return 0;
1117
1118         for (i = 0; i < tp->nr_args; i++)
1119                 if (!trace_seq_printf(s, " %s=%%lx", tp->args[i].name))
1120                         return 0;
1121
1122         if (!trace_seq_printf(s, "\", %s", arg))
1123                 return 0;
1124
1125         for (i = 0; i < tp->nr_args; i++)
1126                 if (!trace_seq_printf(s, ", REC->%s", tp->args[i].name))
1127                         return 0;
1128
1129         return trace_seq_puts(s, "\n");
1130 }
1131
1132 #undef SHOW_FIELD
1133 #define SHOW_FIELD(type, item, name)                                    \
1134         do {                                                            \
1135                 ret = trace_seq_printf(s, "\tfield: " #type " %s;\t"    \
1136                                 "offset:%u;\tsize:%u;\n", name,         \
1137                                 (unsigned int)offsetof(typeof(field), item),\
1138                                 (unsigned int)sizeof(type));            \
1139                 if (!ret)                                               \
1140                         return 0;                                       \
1141         } while (0)
1142
1143 static int kprobe_event_show_format(struct ftrace_event_call *call,
1144                                     struct trace_seq *s)
1145 {
1146         struct kprobe_trace_entry field __attribute__((unused));
1147         int ret, i;
1148         struct trace_probe *tp = (struct trace_probe *)call->data;
1149
1150         SHOW_FIELD(unsigned long, ip, FIELD_STRING_IP);
1151         SHOW_FIELD(int, nargs, FIELD_STRING_NARGS);
1152
1153         /* Show fields */
1154         for (i = 0; i < tp->nr_args; i++)
1155                 SHOW_FIELD(unsigned long, args[i], tp->args[i].name);
1156         trace_seq_puts(s, "\n");
1157
1158         return __probe_event_show_format(s, tp, "(%lx)",
1159                                          "REC->" FIELD_STRING_IP);
1160 }
1161
1162 static int kretprobe_event_show_format(struct ftrace_event_call *call,
1163                                        struct trace_seq *s)
1164 {
1165         struct kretprobe_trace_entry field __attribute__((unused));
1166         int ret, i;
1167         struct trace_probe *tp = (struct trace_probe *)call->data;
1168
1169         SHOW_FIELD(unsigned long, func, FIELD_STRING_FUNC);
1170         SHOW_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP);
1171         SHOW_FIELD(int, nargs, FIELD_STRING_NARGS);
1172
1173         /* Show fields */
1174         for (i = 0; i < tp->nr_args; i++)
1175                 SHOW_FIELD(unsigned long, args[i], tp->args[i].name);
1176         trace_seq_puts(s, "\n");
1177
1178         return __probe_event_show_format(s, tp, "(%lx <- %lx)",
1179                                          "REC->" FIELD_STRING_FUNC
1180                                          ", REC->" FIELD_STRING_RETIP);
1181 }
1182
1183 #ifdef CONFIG_EVENT_PROFILE
1184
1185 /* Kprobe profile handler */
1186 static __kprobes int kprobe_profile_func(struct kprobe *kp,
1187                                          struct pt_regs *regs)
1188 {
1189         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1190         struct ftrace_event_call *call = &tp->call;
1191         struct kprobe_trace_entry *entry;
1192         struct trace_entry *ent;
1193         int size, __size, i, pc, __cpu;
1194         unsigned long irq_flags;
1195         char *raw_data;
1196
1197         pc = preempt_count();
1198         __size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);
1199         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1200         size -= sizeof(u32);
1201         if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE,
1202                      "profile buffer not large enough"))
1203                 return 0;
1204
1205         /*
1206          * Protect the non nmi buffer
1207          * This also protects the rcu read side
1208          */
1209         local_irq_save(irq_flags);
1210         __cpu = smp_processor_id();
1211
1212         if (in_nmi())
1213                 raw_data = rcu_dereference(trace_profile_buf_nmi);
1214         else
1215                 raw_data = rcu_dereference(trace_profile_buf);
1216
1217         if (!raw_data)
1218                 goto end;
1219
1220         raw_data = per_cpu_ptr(raw_data, __cpu);
1221         /* Zero dead bytes from alignment to avoid buffer leak to userspace */
1222         *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
1223         entry = (struct kprobe_trace_entry *)raw_data;
1224         ent = &entry->ent;
1225
1226         tracing_generic_entry_update(ent, irq_flags, pc);
1227         ent->type = call->id;
1228         entry->nargs = tp->nr_args;
1229         entry->ip = (unsigned long)kp->addr;
1230         for (i = 0; i < tp->nr_args; i++)
1231                 entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
1232         perf_tp_event(call->id, entry->ip, 1, entry, size);
1233 end:
1234         local_irq_restore(irq_flags);
1235         return 0;
1236 }
1237
1238 /* Kretprobe profile handler */
1239 static __kprobes int kretprobe_profile_func(struct kretprobe_instance *ri,
1240                                             struct pt_regs *regs)
1241 {
1242         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1243         struct ftrace_event_call *call = &tp->call;
1244         struct kretprobe_trace_entry *entry;
1245         struct trace_entry *ent;
1246         int size, __size, i, pc, __cpu;
1247         unsigned long irq_flags;
1248         char *raw_data;
1249
1250         pc = preempt_count();
1251         __size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);
1252         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1253         size -= sizeof(u32);
1254         if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE,
1255                      "profile buffer not large enough"))
1256                 return 0;
1257
1258         /*
1259          * Protect the non nmi buffer
1260          * This also protects the rcu read side
1261          */
1262         local_irq_save(irq_flags);
1263         __cpu = smp_processor_id();
1264
1265         if (in_nmi())
1266                 raw_data = rcu_dereference(trace_profile_buf_nmi);
1267         else
1268                 raw_data = rcu_dereference(trace_profile_buf);
1269
1270         if (!raw_data)
1271                 goto end;
1272
1273         raw_data = per_cpu_ptr(raw_data, __cpu);
1274         /* Zero dead bytes from alignment to avoid buffer leak to userspace */
1275         *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
1276         entry = (struct kretprobe_trace_entry *)raw_data;
1277         ent = &entry->ent;
1278
1279         tracing_generic_entry_update(ent, irq_flags, pc);
1280         ent->type = call->id;
1281         entry->nargs = tp->nr_args;
1282         entry->func = (unsigned long)tp->rp.kp.addr;
1283         entry->ret_ip = (unsigned long)ri->ret_addr;
1284         for (i = 0; i < tp->nr_args; i++)
1285                 entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
1286         perf_tp_event(call->id, entry->ret_ip, 1, entry, size);
1287 end:
1288         local_irq_restore(irq_flags);
1289         return 0;
1290 }
1291
1292 static int probe_profile_enable(struct ftrace_event_call *call)
1293 {
1294         struct trace_probe *tp = (struct trace_probe *)call->data;
1295
1296         tp->flags |= TP_FLAG_PROFILE;
1297
1298         if (probe_is_return(tp))
1299                 return enable_kretprobe(&tp->rp);
1300         else
1301                 return enable_kprobe(&tp->rp.kp);
1302 }
1303
1304 static void probe_profile_disable(struct ftrace_event_call *call)
1305 {
1306         struct trace_probe *tp = (struct trace_probe *)call->data;
1307
1308         tp->flags &= ~TP_FLAG_PROFILE;
1309
1310         if (!(tp->flags & TP_FLAG_TRACE)) {
1311                 if (probe_is_return(tp))
1312                         disable_kretprobe(&tp->rp);
1313                 else
1314                         disable_kprobe(&tp->rp.kp);
1315         }
1316 }
1317 #endif  /* CONFIG_EVENT_PROFILE */
1318
1319
1320 static __kprobes
1321 int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1322 {
1323         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1324
1325         if (tp->flags & TP_FLAG_TRACE)
1326                 kprobe_trace_func(kp, regs);
1327 #ifdef CONFIG_EVENT_PROFILE
1328         if (tp->flags & TP_FLAG_PROFILE)
1329                 kprobe_profile_func(kp, regs);
1330 #endif  /* CONFIG_EVENT_PROFILE */
1331         return 0;       /* We don't tweek kernel, so just return 0 */
1332 }
1333
1334 static __kprobes
1335 int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1336 {
1337         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1338
1339         if (tp->flags & TP_FLAG_TRACE)
1340                 kretprobe_trace_func(ri, regs);
1341 #ifdef CONFIG_EVENT_PROFILE
1342         if (tp->flags & TP_FLAG_PROFILE)
1343                 kretprobe_profile_func(ri, regs);
1344 #endif  /* CONFIG_EVENT_PROFILE */
1345         return 0;       /* We don't tweek kernel, so just return 0 */
1346 }
1347
1348 static int register_probe_event(struct trace_probe *tp)
1349 {
1350         struct ftrace_event_call *call = &tp->call;
1351         int ret;
1352
1353         /* Initialize ftrace_event_call */
1354         if (probe_is_return(tp)) {
1355                 tp->event.trace = print_kretprobe_event;
1356                 call->raw_init = probe_event_raw_init;
1357                 call->show_format = kretprobe_event_show_format;
1358                 call->define_fields = kretprobe_event_define_fields;
1359         } else {
1360                 tp->event.trace = print_kprobe_event;
1361                 call->raw_init = probe_event_raw_init;
1362                 call->show_format = kprobe_event_show_format;
1363                 call->define_fields = kprobe_event_define_fields;
1364         }
1365         call->event = &tp->event;
1366         call->id = register_ftrace_event(&tp->event);
1367         if (!call->id)
1368                 return -ENODEV;
1369         call->enabled = 0;
1370         call->regfunc = probe_event_enable;
1371         call->unregfunc = probe_event_disable;
1372
1373 #ifdef CONFIG_EVENT_PROFILE
1374         atomic_set(&call->profile_count, -1);
1375         call->profile_enable = probe_profile_enable;
1376         call->profile_disable = probe_profile_disable;
1377 #endif
1378         call->data = tp;
1379         ret = trace_add_event_call(call);
1380         if (ret) {
1381                 pr_info("Failed to register kprobe event: %s\n", call->name);
1382                 unregister_ftrace_event(&tp->event);
1383         }
1384         return ret;
1385 }
1386
1387 static void unregister_probe_event(struct trace_probe *tp)
1388 {
1389         /* tp->event is unregistered in trace_remove_event_call() */
1390         trace_remove_event_call(&tp->call);
1391 }
1392
1393 /* Make a debugfs interface for controling probe points */
1394 static __init int init_kprobe_trace(void)
1395 {
1396         struct dentry *d_tracer;
1397         struct dentry *entry;
1398
1399         d_tracer = tracing_init_dentry();
1400         if (!d_tracer)
1401                 return 0;
1402
1403         entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
1404                                     NULL, &kprobe_events_ops);
1405
1406         /* Event list interface */
1407         if (!entry)
1408                 pr_warning("Could not create debugfs "
1409                            "'kprobe_events' entry\n");
1410
1411         /* Profile interface */
1412         entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
1413                                     NULL, &kprobe_profile_ops);
1414
1415         if (!entry)
1416                 pr_warning("Could not create debugfs "
1417                            "'kprobe_profile' entry\n");
1418         return 0;
1419 }
1420 fs_initcall(init_kprobe_trace);
1421
1422
1423 #ifdef CONFIG_FTRACE_STARTUP_TEST
1424
1425 static int kprobe_trace_selftest_target(int a1, int a2, int a3,
1426                                         int a4, int a5, int a6)
1427 {
1428         return a1 + a2 + a3 + a4 + a5 + a6;
1429 }
1430
1431 static __init int kprobe_trace_self_tests_init(void)
1432 {
1433         int ret;
1434         int (*target)(int, int, int, int, int, int);
1435
1436         target = kprobe_trace_selftest_target;
1437
1438         pr_info("Testing kprobe tracing: ");
1439
1440         ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target "
1441                                   "$arg1 $arg2 $arg3 $arg4 $stack $stack0");
1442         if (WARN_ON_ONCE(ret))
1443                 pr_warning("error enabling function entry\n");
1444
1445         ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target "
1446                                   "$retval");
1447         if (WARN_ON_ONCE(ret))
1448                 pr_warning("error enabling function return\n");
1449
1450         ret = target(1, 2, 3, 4, 5, 6);
1451
1452         cleanup_all_probes();
1453
1454         pr_cont("OK\n");
1455         return 0;
1456 }
1457
1458 late_initcall(kprobe_trace_self_tests_init);
1459
1460 #endif