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