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