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