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