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