kernel/trace/trace_probe.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Common code for probe-based Dynamic events.
   4  *
   5  * This code was copied from kernel/trace/trace_kprobe.c written by
   6  * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
   7  *
   8  * Updates to make this generic:
   9  * Copyright (C) IBM Corporation, 2010-2011
  10  * Author:     Srikar Dronamraju
  11  */
  12 #define pr_fmt(fmt)     "trace_probe: " fmt
  13
  14 #include "trace_probe.h"
  15
  16 #undef C
  17 #define C(a, b)         b
  18
  19 static const char *trace_probe_err_text[] = { ERRORS };
  20
  21 static const char *reserved_field_names[] = {
  22         "common_type",
  23         "common_flags",
  24         "common_preempt_count",
  25         "common_pid",
  26         "common_tgid",
  27         FIELD_STRING_IP,
  28         FIELD_STRING_RETIP,
  29         FIELD_STRING_FUNC,
  30 };
  31
  32 /* Printing  in basic type function template */
  33 #define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt)                  \
  34 int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\
  35 {                                                                       \
  36         trace_seq_printf(s, fmt, *(type *)data);                        \
  37         return !trace_seq_has_overflowed(s);                            \
  38 }                                                                       \
  39 const char PRINT_TYPE_FMT_NAME(tname)[] = fmt;
  40
  41 DEFINE_BASIC_PRINT_TYPE_FUNC(u8,  u8,  "%u")
  42 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
  43 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
  44 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
  45 DEFINE_BASIC_PRINT_TYPE_FUNC(s8,  s8,  "%d")
  46 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
  47 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
  48 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
  49 DEFINE_BASIC_PRINT_TYPE_FUNC(x8,  u8,  "0x%x")
  50 DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
  51 DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
  52 DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
  53
  54 int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent)
  55 {
  56         trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data);
  57         return !trace_seq_has_overflowed(s);
  58 }
  59 const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS";
  60
  61 /* Print type function for string type */
  62 int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)
  63 {
  64         int len = *(u32 *)data >> 16;
  65
  66         if (!len)
  67                 trace_seq_puts(s, "(fault)");
  68         else
  69                 trace_seq_printf(s, "\"%s\"",
  70                                  (const char *)get_loc_data(data, ent));
  71         return !trace_seq_has_overflowed(s);
  72 }
  73
  74 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
  75
  76 /* Fetch type information table */
  77 static const struct fetch_type probe_fetch_types[] = {
  78         /* Special types */
  79         __ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1, 1,
  80                             "__data_loc char[]"),
  81         __ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1, 1,
  82                             "__data_loc char[]"),
  83         __ASSIGN_FETCH_TYPE("symstr", string, string, sizeof(u32), 1, 1,
  84                             "__data_loc char[]"),
  85         /* Basic types */
  86         ASSIGN_FETCH_TYPE(u8,  u8,  0),
  87         ASSIGN_FETCH_TYPE(u16, u16, 0),
  88         ASSIGN_FETCH_TYPE(u32, u32, 0),
  89         ASSIGN_FETCH_TYPE(u64, u64, 0),
  90         ASSIGN_FETCH_TYPE(s8,  u8,  1),
  91         ASSIGN_FETCH_TYPE(s16, u16, 1),
  92         ASSIGN_FETCH_TYPE(s32, u32, 1),
  93         ASSIGN_FETCH_TYPE(s64, u64, 1),
  94         ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),
  95         ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
  96         ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
  97         ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
  98         ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0),
  99
 100         ASSIGN_FETCH_TYPE_END
 101 };
 102
 103 static const struct fetch_type *find_fetch_type(const char *type, unsigned long flags)
 104 {
 105         int i;
 106
 107         /* Reject the symbol/symstr for uprobes */
 108         if (type && (flags & TPARG_FL_USER) &&
 109             (!strcmp(type, "symbol") || !strcmp(type, "symstr")))
 110                 return NULL;
 111
 112         if (!type)
 113                 type = DEFAULT_FETCH_TYPE_STR;
 114
 115         /* Special case: bitfield */
 116         if (*type == 'b') {
 117                 unsigned long bs;
 118
 119                 type = strchr(type, '/');
 120                 if (!type)
 121                         goto fail;
 122
 123                 type++;
 124                 if (kstrtoul(type, 0, &bs))
 125                         goto fail;
 126
 127                 switch (bs) {
 128                 case 8:
 129                         return find_fetch_type("u8", flags);
 130                 case 16:
 131                         return find_fetch_type("u16", flags);
 132                 case 32:
 133                         return find_fetch_type("u32", flags);
 134                 case 64:
 135                         return find_fetch_type("u64", flags);
 136                 default:
 137                         goto fail;
 138                 }
 139         }
 140
 141         for (i = 0; probe_fetch_types[i].name; i++) {
 142                 if (strcmp(type, probe_fetch_types[i].name) == 0)
 143                         return &probe_fetch_types[i];
 144         }
 145
 146 fail:
 147         return NULL;
 148 }
 149
 150 static struct trace_probe_log trace_probe_log;
 151
 152 void trace_probe_log_init(const char *subsystem, int argc, const char **argv)
 153 {
 154         trace_probe_log.subsystem = subsystem;
 155         trace_probe_log.argc = argc;
 156         trace_probe_log.argv = argv;
 157         trace_probe_log.index = 0;
 158 }
 159
 160 void trace_probe_log_clear(void)
 161 {
 162         memset(&trace_probe_log, 0, sizeof(trace_probe_log));
 163 }
 164
 165 void trace_probe_log_set_index(int index)
 166 {
 167         trace_probe_log.index = index;
 168 }
 169
 170 void __trace_probe_log_err(int offset, int err_type)
 171 {
 172         char *command, *p;
 173         int i, len = 0, pos = 0;
 174
 175         if (!trace_probe_log.argv)
 176                 return;
 177
 178         /* Recalculate the length and allocate buffer */
 179         for (i = 0; i < trace_probe_log.argc; i++) {
 180                 if (i == trace_probe_log.index)
 181                         pos = len;
 182                 len += strlen(trace_probe_log.argv[i]) + 1;
 183         }
 184         command = kzalloc(len, GFP_KERNEL);
 185         if (!command)
 186                 return;
 187
 188         if (trace_probe_log.index >= trace_probe_log.argc) {
 189                 /**
 190                  * Set the error position is next to the last arg + space.
 191                  * Note that len includes the terminal null and the cursor
 192                  * appears at pos + 1.
 193                  */
 194                 pos = len;
 195                 offset = 0;
 196         }
 197
 198         /* And make a command string from argv array */
 199         p = command;
 200         for (i = 0; i < trace_probe_log.argc; i++) {
 201                 len = strlen(trace_probe_log.argv[i]);
 202                 strcpy(p, trace_probe_log.argv[i]);
 203                 p[len] = ' ';
 204                 p += len + 1;
 205         }
 206         *(p - 1) = '\0';
 207
 208         tracing_log_err(NULL, trace_probe_log.subsystem, command,
 209                         trace_probe_err_text, err_type, pos + offset);
 210
 211         kfree(command);
 212 }
 213
 214 /* Split symbol and offset. */
 215 int traceprobe_split_symbol_offset(char *symbol, long *offset)
 216 {
 217         char *tmp;
 218         int ret;
 219
 220         if (!offset)
 221                 return -EINVAL;
 222
 223         tmp = strpbrk(symbol, "+-");
 224         if (tmp) {
 225                 ret = kstrtol(tmp, 0, offset);
 226                 if (ret)
 227                         return ret;
 228                 *tmp = '\0';
 229         } else
 230                 *offset = 0;
 231
 232         return 0;
 233 }
 234
 235 /* @buf must has MAX_EVENT_NAME_LEN size */
 236 int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
 237                                 char *buf, int offset)
 238 {
 239         const char *slash, *event = *pevent;
 240         int len;
 241
 242         slash = strchr(event, '/');
 243         if (!slash)
 244                 slash = strchr(event, '.');
 245
 246         if (slash) {
 247                 if (slash == event) {
 248                         trace_probe_log_err(offset, NO_GROUP_NAME);
 249                         return -EINVAL;
 250                 }
 251                 if (slash - event + 1 > MAX_EVENT_NAME_LEN) {
 252                         trace_probe_log_err(offset, GROUP_TOO_LONG);
 253                         return -EINVAL;
 254                 }
 255                 strlcpy(buf, event, slash - event + 1);
 256                 if (!is_good_system_name(buf)) {
 257                         trace_probe_log_err(offset, BAD_GROUP_NAME);
 258                         return -EINVAL;
 259                 }
 260                 *pgroup = buf;
 261                 *pevent = slash + 1;
 262                 offset += slash - event + 1;
 263                 event = *pevent;
 264         }
 265         len = strlen(event);
 266         if (len == 0) {
 267                 if (slash) {
 268                         *pevent = NULL;
 269                         return 0;
 270                 }
 271                 trace_probe_log_err(offset, NO_EVENT_NAME);
 272                 return -EINVAL;
 273         } else if (len > MAX_EVENT_NAME_LEN) {
 274                 trace_probe_log_err(offset, EVENT_TOO_LONG);
 275                 return -EINVAL;
 276         }
 277         if (!is_good_name(event)) {
 278                 trace_probe_log_err(offset, BAD_EVENT_NAME);
 279                 return -EINVAL;
 280         }
 281         return 0;
 282 }
 283
 284 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
 285
 286 static int parse_probe_vars(char *arg, const struct fetch_type *t,
 287                         struct fetch_insn *code, unsigned int flags, int offs)
 288 {
 289         unsigned long param;
 290         int ret = 0;
 291         int len;
 292
 293         if (flags & TPARG_FL_TPOINT) {
 294                 if (code->data)
 295                         return -EFAULT;
 296                 code->data = kstrdup(arg, GFP_KERNEL);
 297                 if (!code->data)
 298                         return -ENOMEM;
 299                 code->op = FETCH_OP_TP_ARG;
 300         } else if (strcmp(arg, "retval") == 0) {
 301                 if (flags & TPARG_FL_RETURN) {
 302                         code->op = FETCH_OP_RETVAL;
 303                 } else {
 304                         trace_probe_log_err(offs, RETVAL_ON_PROBE);
 305                         ret = -EINVAL;
 306                 }
 307         } else if ((len = str_has_prefix(arg, "stack"))) {
 308                 if (arg[len] == '\0') {
 309                         code->op = FETCH_OP_STACKP;
 310                 } else if (isdigit(arg[len])) {
 311                         ret = kstrtoul(arg + len, 10, &param);
 312                         if (ret) {
 313                                 goto inval_var;
 314                         } else if ((flags & TPARG_FL_KERNEL) &&
 315                                     param > PARAM_MAX_STACK) {
 316                                 trace_probe_log_err(offs, BAD_STACK_NUM);
 317                                 ret = -EINVAL;
 318                         } else {
 319                                 code->op = FETCH_OP_STACK;
 320                                 code->param = (unsigned int)param;
 321                         }
 322                 } else
 323                         goto inval_var;
 324         } else if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
 325                 code->op = FETCH_OP_COMM;
 326 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
 327         } else if (((flags & TPARG_FL_MASK) ==
 328                     (TPARG_FL_KERNEL | TPARG_FL_FENTRY)) &&
 329                    (len = str_has_prefix(arg, "arg"))) {
 330                 ret = kstrtoul(arg + len, 10, &param);
 331                 if (ret) {
 332                         goto inval_var;
 333                 } else if (!param || param > PARAM_MAX_STACK) {
 334                         trace_probe_log_err(offs, BAD_ARG_NUM);
 335                         return -EINVAL;
 336                 }
 337                 code->op = FETCH_OP_ARG;
 338                 code->param = (unsigned int)param - 1;
 339 #endif
 340         } else
 341                 goto inval_var;
 342
 343         return ret;
 344
 345 inval_var:
 346         trace_probe_log_err(offs, BAD_VAR);
 347         return -EINVAL;
 348 }
 349
 350 static int str_to_immediate(char *str, unsigned long *imm)
 351 {
 352         if (isdigit(str[0]))
 353                 return kstrtoul(str, 0, imm);
 354         else if (str[0] == '-')
 355                 return kstrtol(str, 0, (long *)imm);
 356         else if (str[0] == '+')
 357                 return kstrtol(str + 1, 0, (long *)imm);
 358         return -EINVAL;
 359 }
 360
 361 static int __parse_imm_string(char *str, char **pbuf, int offs)
 362 {
 363         size_t len = strlen(str);
 364
 365         if (str[len - 1] != '"') {
 366                 trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE);
 367                 return -EINVAL;
 368         }
 369         *pbuf = kstrndup(str, len - 1, GFP_KERNEL);
 370         if (!*pbuf)
 371                 return -ENOMEM;
 372         return 0;
 373 }
 374
 375 /* Recursive argument parser */
 376 static int
 377 parse_probe_arg(char *arg, const struct fetch_type *type,
 378                 struct fetch_insn **pcode, struct fetch_insn *end,
 379                 unsigned int flags, int offs)
 380 {
 381         struct fetch_insn *code = *pcode;
 382         unsigned long param;
 383         int deref = FETCH_OP_DEREF;
 384         long offset = 0;
 385         char *tmp;
 386         int ret = 0;
 387
 388         switch (arg[0]) {
 389         case '$':
 390                 ret = parse_probe_vars(arg + 1, type, code, flags, offs);
 391                 break;
 392
 393         case '%':       /* named register */
 394                 if (flags & TPARG_FL_TPOINT) {
 395                         /* eprobes do not handle registers */
 396                         trace_probe_log_err(offs, BAD_VAR);
 397                         break;
 398                 }
 399                 ret = regs_query_register_offset(arg + 1);
 400                 if (ret >= 0) {
 401                         code->op = FETCH_OP_REG;
 402                         code->param = (unsigned int)ret;
 403                         ret = 0;
 404                 } else
 405                         trace_probe_log_err(offs, BAD_REG_NAME);
 406                 break;
 407
 408         case '@':       /* memory, file-offset or symbol */
 409                 if (isdigit(arg[1])) {
 410                         ret = kstrtoul(arg + 1, 0, &param);
 411                         if (ret) {
 412                                 trace_probe_log_err(offs, BAD_MEM_ADDR);
 413                                 break;
 414                         }
 415                         /* load address */
 416                         code->op = FETCH_OP_IMM;
 417                         code->immediate = param;
 418                 } else if (arg[1] == '+') {
 419                         /* kprobes don't support file offsets */
 420                         if (flags & TPARG_FL_KERNEL) {
 421                                 trace_probe_log_err(offs, FILE_ON_KPROBE);
 422                                 return -EINVAL;
 423                         }
 424                         ret = kstrtol(arg + 2, 0, &offset);
 425                         if (ret) {
 426                                 trace_probe_log_err(offs, BAD_FILE_OFFS);
 427                                 break;
 428                         }
 429
 430                         code->op = FETCH_OP_FOFFS;
 431                         code->immediate = (unsigned long)offset;  // imm64?
 432                 } else {
 433                         /* uprobes don't support symbols */
 434                         if (!(flags & TPARG_FL_KERNEL)) {
 435                                 trace_probe_log_err(offs, SYM_ON_UPROBE);
 436                                 return -EINVAL;
 437                         }
 438                         /* Preserve symbol for updating */
 439                         code->op = FETCH_NOP_SYMBOL;
 440                         code->data = kstrdup(arg + 1, GFP_KERNEL);
 441                         if (!code->data)
 442                                 return -ENOMEM;
 443                         if (++code == end) {
 444                                 trace_probe_log_err(offs, TOO_MANY_OPS);
 445                                 return -EINVAL;
 446                         }
 447                         code->op = FETCH_OP_IMM;
 448                         code->immediate = 0;
 449                 }
 450                 /* These are fetching from memory */
 451                 if (++code == end) {
 452                         trace_probe_log_err(offs, TOO_MANY_OPS);
 453                         return -EINVAL;
 454                 }
 455                 *pcode = code;
 456                 code->op = FETCH_OP_DEREF;
 457                 code->offset = offset;
 458                 break;
 459
 460         case '+':       /* deref memory */
 461         case '-':
 462                 if (arg[1] == 'u') {
 463                         deref = FETCH_OP_UDEREF;
 464                         arg[1] = arg[0];
 465                         arg++;
 466                 }
 467                 if (arg[0] == '+')
 468                         arg++;  /* Skip '+', because kstrtol() rejects it. */
 469                 tmp = strchr(arg, '(');
 470                 if (!tmp) {
 471                         trace_probe_log_err(offs, DEREF_NEED_BRACE);
 472                         return -EINVAL;
 473                 }
 474                 *tmp = '\0';
 475                 ret = kstrtol(arg, 0, &offset);
 476                 if (ret) {
 477                         trace_probe_log_err(offs, BAD_DEREF_OFFS);
 478                         break;
 479                 }
 480                 offs += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
 481                 arg = tmp + 1;
 482                 tmp = strrchr(arg, ')');
 483                 if (!tmp) {
 484                         trace_probe_log_err(offs + strlen(arg),
 485                                             DEREF_OPEN_BRACE);
 486                         return -EINVAL;
 487                 } else {
 488                         const struct fetch_type *t2 = find_fetch_type(NULL, flags);
 489
 490                         *tmp = '\0';
 491                         ret = parse_probe_arg(arg, t2, &code, end, flags, offs);
 492                         if (ret)
 493                                 break;
 494                         if (code->op == FETCH_OP_COMM ||
 495                             code->op == FETCH_OP_DATA) {
 496                                 trace_probe_log_err(offs, COMM_CANT_DEREF);
 497                                 return -EINVAL;
 498                         }
 499                         if (++code == end) {
 500                                 trace_probe_log_err(offs, TOO_MANY_OPS);
 501                                 return -EINVAL;
 502                         }
 503                         *pcode = code;
 504
 505                         code->op = deref;
 506                         code->offset = offset;
 507                 }
 508                 break;
 509         case '\\':      /* Immediate value */
 510                 if (arg[1] == '"') {    /* Immediate string */
 511                         ret = __parse_imm_string(arg + 2, &tmp, offs + 2);
 512                         if (ret)
 513                                 break;
 514                         code->op = FETCH_OP_DATA;
 515                         code->data = tmp;
 516                 } else {
 517                         ret = str_to_immediate(arg + 1, &code->immediate);
 518                         if (ret)
 519                                 trace_probe_log_err(offs + 1, BAD_IMM);
 520                         else
 521                                 code->op = FETCH_OP_IMM;
 522                 }
 523                 break;
 524         }
 525         if (!ret && code->op == FETCH_OP_NOP) {
 526                 /* Parsed, but do not find fetch method */
 527                 trace_probe_log_err(offs, BAD_FETCH_ARG);
 528                 ret = -EINVAL;
 529         }
 530         return ret;
 531 }
 532
 533 #define BYTES_TO_BITS(nb)       ((BITS_PER_LONG * (nb)) / sizeof(long))
 534
 535 /* Bitfield type needs to be parsed into a fetch function */
 536 static int __parse_bitfield_probe_arg(const char *bf,
 537                                       const struct fetch_type *t,
 538                                       struct fetch_insn **pcode)
 539 {
 540         struct fetch_insn *code = *pcode;
 541         unsigned long bw, bo;
 542         char *tail;
 543
 544         if (*bf != 'b')
 545                 return 0;
 546
 547         bw = simple_strtoul(bf + 1, &tail, 0);  /* Use simple one */
 548
 549         if (bw == 0 || *tail != '@')
 550                 return -EINVAL;
 551
 552         bf = tail + 1;
 553         bo = simple_strtoul(bf, &tail, 0);
 554
 555         if (tail == bf || *tail != '/')
 556                 return -EINVAL;
 557         code++;
 558         if (code->op != FETCH_OP_NOP)
 559                 return -EINVAL;
 560         *pcode = code;
 561
 562         code->op = FETCH_OP_MOD_BF;
 563         code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
 564         code->rshift = BYTES_TO_BITS(t->size) - bw;
 565         code->basesize = t->size;
 566
 567         return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
 568 }
 569
 570 /* String length checking wrapper */
 571 static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
 572                 struct probe_arg *parg, unsigned int flags, int offset)
 573 {
 574         struct fetch_insn *code, *scode, *tmp = NULL;
 575         char *t, *t2, *t3;
 576         char *arg;
 577         int ret, len;
 578
 579         arg = kstrdup(argv, GFP_KERNEL);
 580         if (!arg)
 581                 return -ENOMEM;
 582
 583         ret = -EINVAL;
 584         len = strlen(arg);
 585         if (len > MAX_ARGSTR_LEN) {
 586                 trace_probe_log_err(offset, ARG_TOO_LONG);
 587                 goto out;
 588         } else if (len == 0) {
 589                 trace_probe_log_err(offset, NO_ARG_BODY);
 590                 goto out;
 591         }
 592
 593         ret = -ENOMEM;
 594         parg->comm = kstrdup(arg, GFP_KERNEL);
 595         if (!parg->comm)
 596                 goto out;
 597
 598         ret = -EINVAL;
 599         t = strchr(arg, ':');
 600         if (t) {
 601                 *t = '\0';
 602                 t2 = strchr(++t, '[');
 603                 if (t2) {
 604                         *t2++ = '\0';
 605                         t3 = strchr(t2, ']');
 606                         if (!t3) {
 607                                 offset += t2 + strlen(t2) - arg;
 608                                 trace_probe_log_err(offset,
 609                                                     ARRAY_NO_CLOSE);
 610                                 goto out;
 611                         } else if (t3[1] != '\0') {
 612                                 trace_probe_log_err(offset + t3 + 1 - arg,
 613                                                     BAD_ARRAY_SUFFIX);
 614                                 goto out;
 615                         }
 616                         *t3 = '\0';
 617                         if (kstrtouint(t2, 0, &parg->count) || !parg->count) {
 618                                 trace_probe_log_err(offset + t2 - arg,
 619                                                     BAD_ARRAY_NUM);
 620                                 goto out;
 621                         }
 622                         if (parg->count > MAX_ARRAY_LEN) {
 623                                 trace_probe_log_err(offset + t2 - arg,
 624                                                     ARRAY_TOO_BIG);
 625                                 goto out;
 626                         }
 627                 }
 628         }
 629
 630         /*
 631          * Since $comm and immediate string can not be dereferenced,
 632          * we can find those by strcmp. But ignore for eprobes.
 633          */
 634         if (!(flags & TPARG_FL_TPOINT) &&
 635             (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 ||
 636              strncmp(arg, "\\\"", 2) == 0)) {
 637                 /* The type of $comm must be "string", and not an array. */
 638                 if (parg->count || (t && strcmp(t, "string")))
 639                         goto out;
 640                 parg->type = find_fetch_type("string", flags);
 641         } else
 642                 parg->type = find_fetch_type(t, flags);
 643         if (!parg->type) {
 644                 trace_probe_log_err(offset + (t ? (t - arg) : 0), BAD_TYPE);
 645                 goto out;
 646         }
 647         parg->offset = *size;
 648         *size += parg->type->size * (parg->count ?: 1);
 649
 650         ret = -ENOMEM;
 651         if (parg->count) {
 652                 len = strlen(parg->type->fmttype) + 6;
 653                 parg->fmt = kmalloc(len, GFP_KERNEL);
 654                 if (!parg->fmt)
 655                         goto out;
 656                 snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
 657                          parg->count);
 658         }
 659
 660         code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
 661         if (!code)
 662                 goto out;
 663         code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
 664
 665         ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
 666                               flags, offset);
 667         if (ret)
 668                 goto fail;
 669
 670         ret = -EINVAL;
 671         /* Store operation */
 672         if (parg->type->is_string) {
 673                 if (!strcmp(parg->type->name, "symstr")) {
 674                         if (code->op != FETCH_OP_REG && code->op != FETCH_OP_STACK &&
 675                             code->op != FETCH_OP_RETVAL && code->op != FETCH_OP_ARG &&
 676                             code->op != FETCH_OP_DEREF && code->op != FETCH_OP_TP_ARG) {
 677                                 trace_probe_log_err(offset + (t ? (t - arg) : 0),
 678                                                     BAD_SYMSTRING);
 679                                 goto fail;
 680                         }
 681                 } else {
 682                         if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF &&
 683                             code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM &&
 684                             code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) {
 685                                 trace_probe_log_err(offset + (t ? (t - arg) : 0),
 686                                                     BAD_STRING);
 687                                 goto fail;
 688                         }
 689                 }
 690                 if (!strcmp(parg->type->name, "symstr") ||
 691                     (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM ||
 692                      code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG ||
 693                      parg->count) {
 694                         /*
 695                          * IMM, DATA and COMM is pointing actual address, those
 696                          * must be kept, and if parg->count != 0, this is an
 697                          * array of string pointers instead of string address
 698                          * itself.
 699                          * For the symstr, it doesn't need to dereference, thus
 700                          * it just get the value.
 701                          */
 702                         code++;
 703                         if (code->op != FETCH_OP_NOP) {
 704                                 trace_probe_log_err(offset, TOO_MANY_OPS);
 705                                 goto fail;
 706                         }
 707                 }
 708                 /* If op == DEREF, replace it with STRING */
 709                 if (!strcmp(parg->type->name, "ustring") ||
 710                     code->op == FETCH_OP_UDEREF)
 711                         code->op = FETCH_OP_ST_USTRING;
 712                 else if (!strcmp(parg->type->name, "symstr"))
 713                         code->op = FETCH_OP_ST_SYMSTR;
 714                 else
 715                         code->op = FETCH_OP_ST_STRING;
 716                 code->size = parg->type->size;
 717                 parg->dynamic = true;
 718         } else if (code->op == FETCH_OP_DEREF) {
 719                 code->op = FETCH_OP_ST_MEM;
 720                 code->size = parg->type->size;
 721         } else if (code->op == FETCH_OP_UDEREF) {
 722                 code->op = FETCH_OP_ST_UMEM;
 723                 code->size = parg->type->size;
 724         } else {
 725                 code++;
 726                 if (code->op != FETCH_OP_NOP) {
 727                         trace_probe_log_err(offset, TOO_MANY_OPS);
 728                         goto fail;
 729                 }
 730                 code->op = FETCH_OP_ST_RAW;
 731                 code->size = parg->type->size;
 732         }
 733         scode = code;
 734         /* Modify operation */
 735         if (t != NULL) {
 736                 ret = __parse_bitfield_probe_arg(t, parg->type, &code);
 737                 if (ret) {
 738                         trace_probe_log_err(offset + t - arg, BAD_BITFIELD);
 739                         goto fail;
 740                 }
 741         }
 742         ret = -EINVAL;
 743         /* Loop(Array) operation */
 744         if (parg->count) {
 745                 if (scode->op != FETCH_OP_ST_MEM &&
 746                     scode->op != FETCH_OP_ST_STRING &&
 747                     scode->op != FETCH_OP_ST_USTRING) {
 748                         trace_probe_log_err(offset + (t ? (t - arg) : 0),
 749                                             BAD_STRING);
 750                         goto fail;
 751                 }
 752                 code++;
 753                 if (code->op != FETCH_OP_NOP) {
 754                         trace_probe_log_err(offset, TOO_MANY_OPS);
 755                         goto fail;
 756                 }
 757                 code->op = FETCH_OP_LP_ARRAY;
 758                 code->param = parg->count;
 759         }
 760         code++;
 761         code->op = FETCH_OP_END;
 762
 763         ret = 0;
 764         /* Shrink down the code buffer */
 765         parg->code = kcalloc(code - tmp + 1, sizeof(*code), GFP_KERNEL);
 766         if (!parg->code)
 767                 ret = -ENOMEM;
 768         else
 769                 memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
 770
 771 fail:
 772         if (ret) {
 773                 for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
 774                         if (code->op == FETCH_NOP_SYMBOL ||
 775                             code->op == FETCH_OP_DATA)
 776                                 kfree(code->data);
 777         }
 778         kfree(tmp);
 779 out:
 780         kfree(arg);
 781
 782         return ret;
 783 }
 784
 785 /* Return 1 if name is reserved or already used by another argument */
 786 static int traceprobe_conflict_field_name(const char *name,
 787                                           struct probe_arg *args, int narg)
 788 {
 789         int i;
 790
 791         for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
 792                 if (strcmp(reserved_field_names[i], name) == 0)
 793                         return 1;
 794
 795         for (i = 0; i < narg; i++)
 796                 if (strcmp(args[i].name, name) == 0)
 797                         return 1;
 798
 799         return 0;
 800 }
 801
 802 int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg,
 803                                 unsigned int flags)
 804 {
 805         struct probe_arg *parg = &tp->args[i];
 806         const char *body;
 807
 808         /* Increment count for freeing args in error case */
 809         tp->nr_args++;
 810
 811         body = strchr(arg, '=');
 812         if (body) {
 813                 if (body - arg > MAX_ARG_NAME_LEN) {
 814                         trace_probe_log_err(0, ARG_NAME_TOO_LONG);
 815                         return -EINVAL;
 816                 } else if (body == arg) {
 817                         trace_probe_log_err(0, NO_ARG_NAME);
 818                         return -EINVAL;
 819                 }
 820                 parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
 821                 body++;
 822         } else {
 823                 /* If argument name is omitted, set "argN" */
 824                 parg->name = kasprintf(GFP_KERNEL, "arg%d", i + 1);
 825                 body = arg;
 826         }
 827         if (!parg->name)
 828                 return -ENOMEM;
 829
 830         if (!is_good_name(parg->name)) {
 831                 trace_probe_log_err(0, BAD_ARG_NAME);
 832                 return -EINVAL;
 833         }
 834         if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
 835                 trace_probe_log_err(0, USED_ARG_NAME);
 836                 return -EINVAL;
 837         }
 838         /* Parse fetch argument */
 839         return traceprobe_parse_probe_arg_body(body, &tp->size, parg, flags,
 840                                                body - arg);
 841 }
 842
 843 void traceprobe_free_probe_arg(struct probe_arg *arg)
 844 {
 845         struct fetch_insn *code = arg->code;
 846
 847         while (code && code->op != FETCH_OP_END) {
 848                 if (code->op == FETCH_NOP_SYMBOL ||
 849                     code->op == FETCH_OP_DATA)
 850                         kfree(code->data);
 851                 code++;
 852         }
 853         kfree(arg->code);
 854         kfree(arg->name);
 855         kfree(arg->comm);
 856         kfree(arg->fmt);
 857 }
 858
 859 int traceprobe_update_arg(struct probe_arg *arg)
 860 {
 861         struct fetch_insn *code = arg->code;
 862         long offset;
 863         char *tmp;
 864         char c;
 865         int ret = 0;
 866
 867         while (code && code->op != FETCH_OP_END) {
 868                 if (code->op == FETCH_NOP_SYMBOL) {
 869                         if (code[1].op != FETCH_OP_IMM)
 870                                 return -EINVAL;
 871
 872                         tmp = strpbrk(code->data, "+-");
 873                         if (tmp)
 874                                 c = *tmp;
 875                         ret = traceprobe_split_symbol_offset(code->data,
 876                                                              &offset);
 877                         if (ret)
 878                                 return ret;
 879
 880                         code[1].immediate =
 881                                 (unsigned long)kallsyms_lookup_name(code->data);
 882                         if (tmp)
 883                                 *tmp = c;
 884                         if (!code[1].immediate)
 885                                 return -ENOENT;
 886                         code[1].immediate += offset;
 887                 }
 888                 code++;
 889         }
 890         return 0;
 891 }
 892
 893 /* When len=0, we just calculate the needed length */
 894 #define LEN_OR_ZERO (len ? len - pos : 0)
 895 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
 896                            enum probe_print_type ptype)
 897 {
 898         struct probe_arg *parg;
 899         int i, j;
 900         int pos = 0;
 901         const char *fmt, *arg;
 902
 903         switch (ptype) {
 904         case PROBE_PRINT_NORMAL:
 905                 fmt = "(%lx)";
 906                 arg = ", REC->" FIELD_STRING_IP;
 907                 break;
 908         case PROBE_PRINT_RETURN:
 909                 fmt = "(%lx <- %lx)";
 910                 arg = ", REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
 911                 break;
 912         case PROBE_PRINT_EVENT:
 913                 fmt = "";
 914                 arg = "";
 915                 break;
 916         default:
 917                 WARN_ON_ONCE(1);
 918                 return 0;
 919         }
 920
 921         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
 922
 923         for (i = 0; i < tp->nr_args; i++) {
 924                 parg = tp->args + i;
 925                 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name);
 926                 if (parg->count) {
 927                         pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s",
 928                                         parg->type->fmt);
 929                         for (j = 1; j < parg->count; j++)
 930                                 pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s",
 931                                                 parg->type->fmt);
 932                         pos += snprintf(buf + pos, LEN_OR_ZERO, "}");
 933                 } else
 934                         pos += snprintf(buf + pos, LEN_OR_ZERO, "%s",
 935                                         parg->type->fmt);
 936         }
 937
 938         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", arg);
 939
 940         for (i = 0; i < tp->nr_args; i++) {
 941                 parg = tp->args + i;
 942                 if (parg->count) {
 943                         if (parg->type->is_string)
 944                                 fmt = ", __get_str(%s[%d])";
 945                         else
 946                                 fmt = ", REC->%s[%d]";
 947                         for (j = 0; j < parg->count; j++)
 948                                 pos += snprintf(buf + pos, LEN_OR_ZERO,
 949                                                 fmt, parg->name, j);
 950                 } else {
 951                         if (parg->type->is_string)
 952                                 fmt = ", __get_str(%s)";
 953                         else
 954                                 fmt = ", REC->%s";
 955                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 956                                         fmt, parg->name);
 957                 }
 958         }
 959
 960         /* return the length of print_fmt */
 961         return pos;
 962 }
 963 #undef LEN_OR_ZERO
 964
 965 int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype)
 966 {
 967         struct trace_event_call *call = trace_probe_event_call(tp);
 968         int len;
 969         char *print_fmt;
 970
 971         /* First: called with 0 length to calculate the needed length */
 972         len = __set_print_fmt(tp, NULL, 0, ptype);
 973         print_fmt = kmalloc(len + 1, GFP_KERNEL);
 974         if (!print_fmt)
 975                 return -ENOMEM;
 976
 977         /* Second: actually write the @print_fmt */
 978         __set_print_fmt(tp, print_fmt, len + 1, ptype);
 979         call->print_fmt = print_fmt;
 980
 981         return 0;
 982 }
 983
 984 int traceprobe_define_arg_fields(struct trace_event_call *event_call,
 985                                  size_t offset, struct trace_probe *tp)
 986 {
 987         int ret, i;
 988
 989         /* Set argument names as fields */
 990         for (i = 0; i < tp->nr_args; i++) {
 991                 struct probe_arg *parg = &tp->args[i];
 992                 const char *fmt = parg->type->fmttype;
 993                 int size = parg->type->size;
 994
 995                 if (parg->fmt)
 996                         fmt = parg->fmt;
 997                 if (parg->count)
 998                         size *= parg->count;
 999                 ret = trace_define_field(event_call, fmt, parg->name,
1000                                          offset + parg->offset, size,
1001                                          parg->type->is_signed,
1002                                          FILTER_OTHER);
1003                 if (ret)
1004                         return ret;
1005         }
1006         return 0;
1007 }
1008
1009 static void trace_probe_event_free(struct trace_probe_event *tpe)
1010 {
1011         kfree(tpe->class.system);
1012         kfree(tpe->call.name);
1013         kfree(tpe->call.print_fmt);
1014         kfree(tpe);
1015 }
1016
1017 int trace_probe_append(struct trace_probe *tp, struct trace_probe *to)
1018 {
1019         if (trace_probe_has_sibling(tp))
1020                 return -EBUSY;
1021
1022         list_del_init(&tp->list);
1023         trace_probe_event_free(tp->event);
1024
1025         tp->event = to->event;
1026         list_add_tail(&tp->list, trace_probe_probe_list(to));
1027
1028         return 0;
1029 }
1030
1031 void trace_probe_unlink(struct trace_probe *tp)
1032 {
1033         list_del_init(&tp->list);
1034         if (list_empty(trace_probe_probe_list(tp)))
1035                 trace_probe_event_free(tp->event);
1036         tp->event = NULL;
1037 }
1038
1039 void trace_probe_cleanup(struct trace_probe *tp)
1040 {
1041         int i;
1042
1043         for (i = 0; i < tp->nr_args; i++)
1044                 traceprobe_free_probe_arg(&tp->args[i]);
1045
1046         if (tp->event)
1047                 trace_probe_unlink(tp);
1048 }
1049
1050 int trace_probe_init(struct trace_probe *tp, const char *event,
1051                      const char *group, bool alloc_filter)
1052 {
1053         struct trace_event_call *call;
1054         size_t size = sizeof(struct trace_probe_event);
1055         int ret = 0;
1056
1057         if (!event || !group)
1058                 return -EINVAL;
1059
1060         if (alloc_filter)
1061                 size += sizeof(struct trace_uprobe_filter);
1062
1063         tp->event = kzalloc(size, GFP_KERNEL);
1064         if (!tp->event)
1065                 return -ENOMEM;
1066
1067         INIT_LIST_HEAD(&tp->event->files);
1068         INIT_LIST_HEAD(&tp->event->class.fields);
1069         INIT_LIST_HEAD(&tp->event->probes);
1070         INIT_LIST_HEAD(&tp->list);
1071         list_add(&tp->list, &tp->event->probes);
1072
1073         call = trace_probe_event_call(tp);
1074         call->class = &tp->event->class;
1075         call->name = kstrdup(event, GFP_KERNEL);
1076         if (!call->name) {
1077                 ret = -ENOMEM;
1078                 goto error;
1079         }
1080
1081         tp->event->class.system = kstrdup(group, GFP_KERNEL);
1082         if (!tp->event->class.system) {
1083                 ret = -ENOMEM;
1084                 goto error;
1085         }
1086
1087         return 0;
1088
1089 error:
1090         trace_probe_cleanup(tp);
1091         return ret;
1092 }
1093
1094 static struct trace_event_call *
1095 find_trace_event_call(const char *system, const char *event_name)
1096 {
1097         struct trace_event_call *tp_event;
1098         const char *name;
1099
1100         list_for_each_entry(tp_event, &ftrace_events, list) {
1101                 if (!tp_event->class->system ||
1102                     strcmp(system, tp_event->class->system))
1103                         continue;
1104                 name = trace_event_name(tp_event);
1105                 if (!name || strcmp(event_name, name))
1106                         continue;
1107                 return tp_event;
1108         }
1109
1110         return NULL;
1111 }
1112
1113 int trace_probe_register_event_call(struct trace_probe *tp)
1114 {
1115         struct trace_event_call *call = trace_probe_event_call(tp);
1116         int ret;
1117
1118         lockdep_assert_held(&event_mutex);
1119
1120         if (find_trace_event_call(trace_probe_group_name(tp),
1121                                   trace_probe_name(tp)))
1122                 return -EEXIST;
1123
1124         ret = register_trace_event(&call->event);
1125         if (!ret)
1126                 return -ENODEV;
1127
1128         ret = trace_add_event_call(call);
1129         if (ret)
1130                 unregister_trace_event(&call->event);
1131
1132         return ret;
1133 }
1134
1135 int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file)
1136 {
1137         struct event_file_link *link;
1138
1139         link = kmalloc(sizeof(*link), GFP_KERNEL);
1140         if (!link)
1141                 return -ENOMEM;
1142
1143         link->file = file;
1144         INIT_LIST_HEAD(&link->list);
1145         list_add_tail_rcu(&link->list, &tp->event->files);
1146         trace_probe_set_flag(tp, TP_FLAG_TRACE);
1147         return 0;
1148 }
1149
1150 struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
1151                                                   struct trace_event_file *file)
1152 {
1153         struct event_file_link *link;
1154
1155         trace_probe_for_each_link(link, tp) {
1156                 if (link->file == file)
1157                         return link;
1158         }
1159
1160         return NULL;
1161 }
1162
1163 int trace_probe_remove_file(struct trace_probe *tp,
1164                             struct trace_event_file *file)
1165 {
1166         struct event_file_link *link;
1167
1168         link = trace_probe_get_file_link(tp, file);
1169         if (!link)
1170                 return -ENOENT;
1171
1172         list_del_rcu(&link->list);
1173         kvfree_rcu(link);
1174
1175         if (list_empty(&tp->event->files))
1176                 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
1177
1178         return 0;
1179 }
1180
1181 /*
1182  * Return the smallest index of different type argument (start from 1).
1183  * If all argument types and name are same, return 0.
1184  */
1185 int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
1186 {
1187         int i;
1188
1189         /* In case of more arguments */
1190         if (a->nr_args < b->nr_args)
1191                 return a->nr_args + 1;
1192         if (a->nr_args > b->nr_args)
1193                 return b->nr_args + 1;
1194
1195         for (i = 0; i < a->nr_args; i++) {
1196                 if ((b->nr_args <= i) ||
1197                     ((a->args[i].type != b->args[i].type) ||
1198                      (a->args[i].count != b->args[i].count) ||
1199                      strcmp(a->args[i].name, b->args[i].name)))
1200                         return i + 1;
1201         }
1202
1203         return 0;
1204 }
1205
1206 bool trace_probe_match_command_args(struct trace_probe *tp,
1207                                     int argc, const char **argv)
1208 {
1209         char buf[MAX_ARGSTR_LEN + 1];
1210         int i;
1211
1212         if (tp->nr_args < argc)
1213                 return false;
1214
1215         for (i = 0; i < argc; i++) {
1216                 snprintf(buf, sizeof(buf), "%s=%s",
1217                          tp->args[i].name, tp->args[i].comm);
1218                 if (strcmp(buf, argv[i]))
1219                         return false;
1220         }
1221         return true;
1222 }
1223
1224 int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **))
1225 {
1226         int argc = 0, ret = 0;
1227         char **argv;
1228
1229         argv = argv_split(GFP_KERNEL, raw_command, &argc);
1230         if (!argv)
1231                 return -ENOMEM;
1232
1233         if (argc)
1234                 ret = createfn(argc, (const char **)argv);
1235
1236         argv_free(argv);
1237
1238         return ret;
1239 }