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         /* Basic types */
  82         ASSIGN_FETCH_TYPE(u8,  u8,  0),
  83         ASSIGN_FETCH_TYPE(u16, u16, 0),
  84         ASSIGN_FETCH_TYPE(u32, u32, 0),
  85         ASSIGN_FETCH_TYPE(u64, u64, 0),
  86         ASSIGN_FETCH_TYPE(s8,  u8,  1),
  87         ASSIGN_FETCH_TYPE(s16, u16, 1),
  88         ASSIGN_FETCH_TYPE(s32, u32, 1),
  89         ASSIGN_FETCH_TYPE(s64, u64, 1),
  90         ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),
  91         ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
  92         ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
  93         ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
  94         ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0),
  95
  96         ASSIGN_FETCH_TYPE_END
  97 };
  98
  99 static const struct fetch_type *find_fetch_type(const char *type)
 100 {
 101         int i;
 102
 103         if (!type)
 104                 type = DEFAULT_FETCH_TYPE_STR;
 105
 106         /* Special case: bitfield */
 107         if (*type == 'b') {
 108                 unsigned long bs;
 109
 110                 type = strchr(type, '/');
 111                 if (!type)
 112                         goto fail;
 113
 114                 type++;
 115                 if (kstrtoul(type, 0, &bs))
 116                         goto fail;
 117
 118                 switch (bs) {
 119                 case 8:
 120                         return find_fetch_type("u8");
 121                 case 16:
 122                         return find_fetch_type("u16");
 123                 case 32:
 124                         return find_fetch_type("u32");
 125                 case 64:
 126                         return find_fetch_type("u64");
 127                 default:
 128                         goto fail;
 129                 }
 130         }
 131
 132         for (i = 0; probe_fetch_types[i].name; i++) {
 133                 if (strcmp(type, probe_fetch_types[i].name) == 0)
 134                         return &probe_fetch_types[i];
 135         }
 136
 137 fail:
 138         return NULL;
 139 }
 140
 141 static struct trace_probe_log trace_probe_log;
 142
 143 void trace_probe_log_init(const char *subsystem, int argc, const char **argv)
 144 {
 145         trace_probe_log.subsystem = subsystem;
 146         trace_probe_log.argc = argc;
 147         trace_probe_log.argv = argv;
 148         trace_probe_log.index = 0;
 149 }
 150
 151 void trace_probe_log_clear(void)
 152 {
 153         memset(&trace_probe_log, 0, sizeof(trace_probe_log));
 154 }
 155
 156 void trace_probe_log_set_index(int index)
 157 {
 158         trace_probe_log.index = index;
 159 }
 160
 161 void __trace_probe_log_err(int offset, int err_type)
 162 {
 163         char *command, *p;
 164         int i, len = 0, pos = 0;
 165
 166         if (!trace_probe_log.argv)
 167                 return;
 168
 169         /* Recalcurate the length and allocate buffer */
 170         for (i = 0; i < trace_probe_log.argc; i++) {
 171                 if (i == trace_probe_log.index)
 172                         pos = len;
 173                 len += strlen(trace_probe_log.argv[i]) + 1;
 174         }
 175         command = kzalloc(len, GFP_KERNEL);
 176         if (!command)
 177                 return;
 178
 179         /* And make a command string from argv array */
 180         p = command;
 181         for (i = 0; i < trace_probe_log.argc; i++) {
 182                 len = strlen(trace_probe_log.argv[i]);
 183                 strcpy(p, trace_probe_log.argv[i]);
 184                 p[len] = ' ';
 185                 p += len + 1;
 186         }
 187         *(p - 1) = '\0';
 188
 189         tracing_log_err(NULL, trace_probe_log.subsystem, command,
 190                         trace_probe_err_text, err_type, pos + offset);
 191
 192         kfree(command);
 193 }
 194
 195 /* Split symbol and offset. */
 196 int traceprobe_split_symbol_offset(char *symbol, long *offset)
 197 {
 198         char *tmp;
 199         int ret;
 200
 201         if (!offset)
 202                 return -EINVAL;
 203
 204         tmp = strpbrk(symbol, "+-");
 205         if (tmp) {
 206                 ret = kstrtol(tmp, 0, offset);
 207                 if (ret)
 208                         return ret;
 209                 *tmp = '\0';
 210         } else
 211                 *offset = 0;
 212
 213         return 0;
 214 }
 215
 216 /* @buf must has MAX_EVENT_NAME_LEN size */
 217 int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
 218                                 char *buf, int offset)
 219 {
 220         const char *slash, *event = *pevent;
 221         int len;
 222
 223         slash = strchr(event, '/');
 224         if (slash) {
 225                 if (slash == event) {
 226                         trace_probe_log_err(offset, NO_GROUP_NAME);
 227                         return -EINVAL;
 228                 }
 229                 if (slash - event + 1 > MAX_EVENT_NAME_LEN) {
 230                         trace_probe_log_err(offset, GROUP_TOO_LONG);
 231                         return -EINVAL;
 232                 }
 233                 strlcpy(buf, event, slash - event + 1);
 234                 if (!is_good_name(buf)) {
 235                         trace_probe_log_err(offset, BAD_GROUP_NAME);
 236                         return -EINVAL;
 237                 }
 238                 *pgroup = buf;
 239                 *pevent = slash + 1;
 240                 offset += slash - event + 1;
 241                 event = *pevent;
 242         }
 243         len = strlen(event);
 244         if (len == 0) {
 245                 trace_probe_log_err(offset, NO_EVENT_NAME);
 246                 return -EINVAL;
 247         } else if (len > MAX_EVENT_NAME_LEN) {
 248                 trace_probe_log_err(offset, EVENT_TOO_LONG);
 249                 return -EINVAL;
 250         }
 251         if (!is_good_name(event)) {
 252                 trace_probe_log_err(offset, BAD_EVENT_NAME);
 253                 return -EINVAL;
 254         }
 255         return 0;
 256 }
 257
 258 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
 259
 260 static int parse_probe_vars(char *arg, const struct fetch_type *t,
 261                         struct fetch_insn *code, unsigned int flags, int offs)
 262 {
 263         unsigned long param;
 264         int ret = 0;
 265         int len;
 266
 267         if (strcmp(arg, "retval") == 0) {
 268                 if (flags & TPARG_FL_RETURN) {
 269                         code->op = FETCH_OP_RETVAL;
 270                 } else {
 271                         trace_probe_log_err(offs, RETVAL_ON_PROBE);
 272                         ret = -EINVAL;
 273                 }
 274         } else if ((len = str_has_prefix(arg, "stack"))) {
 275                 if (arg[len] == '\0') {
 276                         code->op = FETCH_OP_STACKP;
 277                 } else if (isdigit(arg[len])) {
 278                         ret = kstrtoul(arg + len, 10, &param);
 279                         if (ret) {
 280                                 goto inval_var;
 281                         } else if ((flags & TPARG_FL_KERNEL) &&
 282                                     param > PARAM_MAX_STACK) {
 283                                 trace_probe_log_err(offs, BAD_STACK_NUM);
 284                                 ret = -EINVAL;
 285                         } else {
 286                                 code->op = FETCH_OP_STACK;
 287                                 code->param = (unsigned int)param;
 288                         }
 289                 } else
 290                         goto inval_var;
 291         } else if (strcmp(arg, "comm") == 0) {
 292                 code->op = FETCH_OP_COMM;
 293 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
 294         } else if (((flags & TPARG_FL_MASK) ==
 295                     (TPARG_FL_KERNEL | TPARG_FL_FENTRY)) &&
 296                    (len = str_has_prefix(arg, "arg"))) {
 297                 ret = kstrtoul(arg + len, 10, &param);
 298                 if (ret) {
 299                         goto inval_var;
 300                 } else if (!param || param > PARAM_MAX_STACK) {
 301                         trace_probe_log_err(offs, BAD_ARG_NUM);
 302                         return -EINVAL;
 303                 }
 304                 code->op = FETCH_OP_ARG;
 305                 code->param = (unsigned int)param - 1;
 306 #endif
 307         } else
 308                 goto inval_var;
 309
 310         return ret;
 311
 312 inval_var:
 313         trace_probe_log_err(offs, BAD_VAR);
 314         return -EINVAL;
 315 }
 316
 317 /* Recursive argument parser */
 318 static int
 319 parse_probe_arg(char *arg, const struct fetch_type *type,
 320                 struct fetch_insn **pcode, struct fetch_insn *end,
 321                 unsigned int flags, int offs)
 322 {
 323         struct fetch_insn *code = *pcode;
 324         unsigned long param;
 325         long offset = 0;
 326         char *tmp;
 327         int ret = 0;
 328
 329         switch (arg[0]) {
 330         case '$':
 331                 ret = parse_probe_vars(arg + 1, type, code, flags, offs);
 332                 break;
 333
 334         case '%':       /* named register */
 335                 ret = regs_query_register_offset(arg + 1);
 336                 if (ret >= 0) {
 337                         code->op = FETCH_OP_REG;
 338                         code->param = (unsigned int)ret;
 339                         ret = 0;
 340                 } else
 341                         trace_probe_log_err(offs, BAD_REG_NAME);
 342                 break;
 343
 344         case '@':       /* memory, file-offset or symbol */
 345                 if (isdigit(arg[1])) {
 346                         ret = kstrtoul(arg + 1, 0, &param);
 347                         if (ret) {
 348                                 trace_probe_log_err(offs, BAD_MEM_ADDR);
 349                                 break;
 350                         }
 351                         /* load address */
 352                         code->op = FETCH_OP_IMM;
 353                         code->immediate = param;
 354                 } else if (arg[1] == '+') {
 355                         /* kprobes don't support file offsets */
 356                         if (flags & TPARG_FL_KERNEL) {
 357                                 trace_probe_log_err(offs, FILE_ON_KPROBE);
 358                                 return -EINVAL;
 359                         }
 360                         ret = kstrtol(arg + 2, 0, &offset);
 361                         if (ret) {
 362                                 trace_probe_log_err(offs, BAD_FILE_OFFS);
 363                                 break;
 364                         }
 365
 366                         code->op = FETCH_OP_FOFFS;
 367                         code->immediate = (unsigned long)offset;  // imm64?
 368                 } else {
 369                         /* uprobes don't support symbols */
 370                         if (!(flags & TPARG_FL_KERNEL)) {
 371                                 trace_probe_log_err(offs, SYM_ON_UPROBE);
 372                                 return -EINVAL;
 373                         }
 374                         /* Preserve symbol for updating */
 375                         code->op = FETCH_NOP_SYMBOL;
 376                         code->data = kstrdup(arg + 1, GFP_KERNEL);
 377                         if (!code->data)
 378                                 return -ENOMEM;
 379                         if (++code == end) {
 380                                 trace_probe_log_err(offs, TOO_MANY_OPS);
 381                                 return -EINVAL;
 382                         }
 383                         code->op = FETCH_OP_IMM;
 384                         code->immediate = 0;
 385                 }
 386                 /* These are fetching from memory */
 387                 if (++code == end) {
 388                         trace_probe_log_err(offs, TOO_MANY_OPS);
 389                         return -EINVAL;
 390                 }
 391                 *pcode = code;
 392                 code->op = FETCH_OP_DEREF;
 393                 code->offset = offset;
 394                 break;
 395
 396         case '+':       /* deref memory */
 397                 arg++;  /* Skip '+', because kstrtol() rejects it. */
 398                 /* fall through */
 399         case '-':
 400                 tmp = strchr(arg, '(');
 401                 if (!tmp) {
 402                         trace_probe_log_err(offs, DEREF_NEED_BRACE);
 403                         return -EINVAL;
 404                 }
 405                 *tmp = '\0';
 406                 ret = kstrtol(arg, 0, &offset);
 407                 if (ret) {
 408                         trace_probe_log_err(offs, BAD_DEREF_OFFS);
 409                         break;
 410                 }
 411                 offs += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
 412                 arg = tmp + 1;
 413                 tmp = strrchr(arg, ')');
 414                 if (!tmp) {
 415                         trace_probe_log_err(offs + strlen(arg),
 416                                             DEREF_OPEN_BRACE);
 417                         return -EINVAL;
 418                 } else {
 419                         const struct fetch_type *t2 = find_fetch_type(NULL);
 420
 421                         *tmp = '\0';
 422                         ret = parse_probe_arg(arg, t2, &code, end, flags, offs);
 423                         if (ret)
 424                                 break;
 425                         if (code->op == FETCH_OP_COMM) {
 426                                 trace_probe_log_err(offs, COMM_CANT_DEREF);
 427                                 return -EINVAL;
 428                         }
 429                         if (++code == end) {
 430                                 trace_probe_log_err(offs, TOO_MANY_OPS);
 431                                 return -EINVAL;
 432                         }
 433                         *pcode = code;
 434
 435                         code->op = FETCH_OP_DEREF;
 436                         code->offset = offset;
 437                 }
 438                 break;
 439         }
 440         if (!ret && code->op == FETCH_OP_NOP) {
 441                 /* Parsed, but do not find fetch method */
 442                 trace_probe_log_err(offs, BAD_FETCH_ARG);
 443                 ret = -EINVAL;
 444         }
 445         return ret;
 446 }
 447
 448 #define BYTES_TO_BITS(nb)       ((BITS_PER_LONG * (nb)) / sizeof(long))
 449
 450 /* Bitfield type needs to be parsed into a fetch function */
 451 static int __parse_bitfield_probe_arg(const char *bf,
 452                                       const struct fetch_type *t,
 453                                       struct fetch_insn **pcode)
 454 {
 455         struct fetch_insn *code = *pcode;
 456         unsigned long bw, bo;
 457         char *tail;
 458
 459         if (*bf != 'b')
 460                 return 0;
 461
 462         bw = simple_strtoul(bf + 1, &tail, 0);  /* Use simple one */
 463
 464         if (bw == 0 || *tail != '@')
 465                 return -EINVAL;
 466
 467         bf = tail + 1;
 468         bo = simple_strtoul(bf, &tail, 0);
 469
 470         if (tail == bf || *tail != '/')
 471                 return -EINVAL;
 472         code++;
 473         if (code->op != FETCH_OP_NOP)
 474                 return -EINVAL;
 475         *pcode = code;
 476
 477         code->op = FETCH_OP_MOD_BF;
 478         code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
 479         code->rshift = BYTES_TO_BITS(t->size) - bw;
 480         code->basesize = t->size;
 481
 482         return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
 483 }
 484
 485 /* String length checking wrapper */
 486 static int traceprobe_parse_probe_arg_body(char *arg, ssize_t *size,
 487                 struct probe_arg *parg, unsigned int flags, int offset)
 488 {
 489         struct fetch_insn *code, *scode, *tmp = NULL;
 490         char *t, *t2, *t3;
 491         int ret, len;
 492
 493         len = strlen(arg);
 494         if (len > MAX_ARGSTR_LEN) {
 495                 trace_probe_log_err(offset, ARG_TOO_LONG);
 496                 return -EINVAL;
 497         } else if (len == 0) {
 498                 trace_probe_log_err(offset, NO_ARG_BODY);
 499                 return -EINVAL;
 500         }
 501
 502         parg->comm = kstrdup(arg, GFP_KERNEL);
 503         if (!parg->comm)
 504                 return -ENOMEM;
 505
 506         t = strchr(arg, ':');
 507         if (t) {
 508                 *t = '\0';
 509                 t2 = strchr(++t, '[');
 510                 if (t2) {
 511                         *t2++ = '\0';
 512                         t3 = strchr(t2, ']');
 513                         if (!t3) {
 514                                 offset += t2 + strlen(t2) - arg;
 515                                 trace_probe_log_err(offset,
 516                                                     ARRAY_NO_CLOSE);
 517                                 return -EINVAL;
 518                         } else if (t3[1] != '\0') {
 519                                 trace_probe_log_err(offset + t3 + 1 - arg,
 520                                                     BAD_ARRAY_SUFFIX);
 521                                 return -EINVAL;
 522                         }
 523                         *t3 = '\0';
 524                         if (kstrtouint(t2, 0, &parg->count) || !parg->count) {
 525                                 trace_probe_log_err(offset + t2 - arg,
 526                                                     BAD_ARRAY_NUM);
 527                                 return -EINVAL;
 528                         }
 529                         if (parg->count > MAX_ARRAY_LEN) {
 530                                 trace_probe_log_err(offset + t2 - arg,
 531                                                     ARRAY_TOO_BIG);
 532                                 return -EINVAL;
 533                         }
 534                 }
 535         }
 536
 537         /* Since $comm can not be dereferred, we can find $comm by strcmp */
 538         if (strcmp(arg, "$comm") == 0) {
 539                 /* The type of $comm must be "string", and not an array. */
 540                 if (parg->count || (t && strcmp(t, "string")))
 541                         return -EINVAL;
 542                 parg->type = find_fetch_type("string");
 543         } else
 544                 parg->type = find_fetch_type(t);
 545         if (!parg->type) {
 546                 trace_probe_log_err(offset + (t ? (t - arg) : 0), BAD_TYPE);
 547                 return -EINVAL;
 548         }
 549         parg->offset = *size;
 550         *size += parg->type->size * (parg->count ?: 1);
 551
 552         if (parg->count) {
 553                 len = strlen(parg->type->fmttype) + 6;
 554                 parg->fmt = kmalloc(len, GFP_KERNEL);
 555                 if (!parg->fmt)
 556                         return -ENOMEM;
 557                 snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
 558                          parg->count);
 559         }
 560
 561         code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
 562         if (!code)
 563                 return -ENOMEM;
 564         code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
 565
 566         ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
 567                               flags, offset);
 568         if (ret)
 569                 goto fail;
 570
 571         /* Store operation */
 572         if (!strcmp(parg->type->name, "string")) {
 573                 if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_IMM &&
 574                     code->op != FETCH_OP_COMM) {
 575                         trace_probe_log_err(offset + (t ? (t - arg) : 0),
 576                                             BAD_STRING);
 577                         ret = -EINVAL;
 578                         goto fail;
 579                 }
 580                 if (code->op != FETCH_OP_DEREF || parg->count) {
 581                         /*
 582                          * IMM and COMM is pointing actual address, those must
 583                          * be kept, and if parg->count != 0, this is an array
 584                          * of string pointers instead of string address itself.
 585                          */
 586                         code++;
 587                         if (code->op != FETCH_OP_NOP) {
 588                                 trace_probe_log_err(offset, TOO_MANY_OPS);
 589                                 ret = -EINVAL;
 590                                 goto fail;
 591                         }
 592                 }
 593                 code->op = FETCH_OP_ST_STRING;  /* In DEREF case, replace it */
 594                 code->size = parg->type->size;
 595                 parg->dynamic = true;
 596         } else if (code->op == FETCH_OP_DEREF) {
 597                 code->op = FETCH_OP_ST_MEM;
 598                 code->size = parg->type->size;
 599         } else {
 600                 code++;
 601                 if (code->op != FETCH_OP_NOP) {
 602                         trace_probe_log_err(offset, TOO_MANY_OPS);
 603                         ret = -EINVAL;
 604                         goto fail;
 605                 }
 606                 code->op = FETCH_OP_ST_RAW;
 607                 code->size = parg->type->size;
 608         }
 609         scode = code;
 610         /* Modify operation */
 611         if (t != NULL) {
 612                 ret = __parse_bitfield_probe_arg(t, parg->type, &code);
 613                 if (ret) {
 614                         trace_probe_log_err(offset + t - arg, BAD_BITFIELD);
 615                         goto fail;
 616                 }
 617         }
 618         /* Loop(Array) operation */
 619         if (parg->count) {
 620                 if (scode->op != FETCH_OP_ST_MEM &&
 621                     scode->op != FETCH_OP_ST_STRING) {
 622                         trace_probe_log_err(offset + (t ? (t - arg) : 0),
 623                                             BAD_STRING);
 624                         ret = -EINVAL;
 625                         goto fail;
 626                 }
 627                 code++;
 628                 if (code->op != FETCH_OP_NOP) {
 629                         trace_probe_log_err(offset, TOO_MANY_OPS);
 630                         ret = -EINVAL;
 631                         goto fail;
 632                 }
 633                 code->op = FETCH_OP_LP_ARRAY;
 634                 code->param = parg->count;
 635         }
 636         code++;
 637         code->op = FETCH_OP_END;
 638
 639         /* Shrink down the code buffer */
 640         parg->code = kcalloc(code - tmp + 1, sizeof(*code), GFP_KERNEL);
 641         if (!parg->code)
 642                 ret = -ENOMEM;
 643         else
 644                 memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
 645
 646 fail:
 647         if (ret) {
 648                 for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
 649                         if (code->op == FETCH_NOP_SYMBOL)
 650                                 kfree(code->data);
 651         }
 652         kfree(tmp);
 653
 654         return ret;
 655 }
 656
 657 /* Return 1 if name is reserved or already used by another argument */
 658 static int traceprobe_conflict_field_name(const char *name,
 659                                           struct probe_arg *args, int narg)
 660 {
 661         int i;
 662
 663         for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
 664                 if (strcmp(reserved_field_names[i], name) == 0)
 665                         return 1;
 666
 667         for (i = 0; i < narg; i++)
 668                 if (strcmp(args[i].name, name) == 0)
 669                         return 1;
 670
 671         return 0;
 672 }
 673
 674 int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, char *arg,
 675                                 unsigned int flags)
 676 {
 677         struct probe_arg *parg = &tp->args[i];
 678         char *body;
 679
 680         /* Increment count for freeing args in error case */
 681         tp->nr_args++;
 682
 683         body = strchr(arg, '=');
 684         if (body) {
 685                 if (body - arg > MAX_ARG_NAME_LEN) {
 686                         trace_probe_log_err(0, ARG_NAME_TOO_LONG);
 687                         return -EINVAL;
 688                 } else if (body == arg) {
 689                         trace_probe_log_err(0, NO_ARG_NAME);
 690                         return -EINVAL;
 691                 }
 692                 parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
 693                 body++;
 694         } else {
 695                 /* If argument name is omitted, set "argN" */
 696                 parg->name = kasprintf(GFP_KERNEL, "arg%d", i + 1);
 697                 body = arg;
 698         }
 699         if (!parg->name)
 700                 return -ENOMEM;
 701
 702         if (!is_good_name(parg->name)) {
 703                 trace_probe_log_err(0, BAD_ARG_NAME);
 704                 return -EINVAL;
 705         }
 706         if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
 707                 trace_probe_log_err(0, USED_ARG_NAME);
 708                 return -EINVAL;
 709         }
 710         /* Parse fetch argument */
 711         return traceprobe_parse_probe_arg_body(body, &tp->size, parg, flags,
 712                                                body - arg);
 713 }
 714
 715 void traceprobe_free_probe_arg(struct probe_arg *arg)
 716 {
 717         struct fetch_insn *code = arg->code;
 718
 719         while (code && code->op != FETCH_OP_END) {
 720                 if (code->op == FETCH_NOP_SYMBOL)
 721                         kfree(code->data);
 722                 code++;
 723         }
 724         kfree(arg->code);
 725         kfree(arg->name);
 726         kfree(arg->comm);
 727         kfree(arg->fmt);
 728 }
 729
 730 int traceprobe_update_arg(struct probe_arg *arg)
 731 {
 732         struct fetch_insn *code = arg->code;
 733         long offset;
 734         char *tmp;
 735         char c;
 736         int ret = 0;
 737
 738         while (code && code->op != FETCH_OP_END) {
 739                 if (code->op == FETCH_NOP_SYMBOL) {
 740                         if (code[1].op != FETCH_OP_IMM)
 741                                 return -EINVAL;
 742
 743                         tmp = strpbrk(code->data, "+-");
 744                         if (tmp)
 745                                 c = *tmp;
 746                         ret = traceprobe_split_symbol_offset(code->data,
 747                                                              &offset);
 748                         if (ret)
 749                                 return ret;
 750
 751                         code[1].immediate =
 752                                 (unsigned long)kallsyms_lookup_name(code->data);
 753                         if (tmp)
 754                                 *tmp = c;
 755                         if (!code[1].immediate)
 756                                 return -ENOENT;
 757                         code[1].immediate += offset;
 758                 }
 759                 code++;
 760         }
 761         return 0;
 762 }
 763
 764 /* When len=0, we just calculate the needed length */
 765 #define LEN_OR_ZERO (len ? len - pos : 0)
 766 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
 767                            bool is_return)
 768 {
 769         struct probe_arg *parg;
 770         int i, j;
 771         int pos = 0;
 772         const char *fmt, *arg;
 773
 774         if (!is_return) {
 775                 fmt = "(%lx)";
 776                 arg = "REC->" FIELD_STRING_IP;
 777         } else {
 778                 fmt = "(%lx <- %lx)";
 779                 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
 780         }
 781
 782         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
 783
 784         for (i = 0; i < tp->nr_args; i++) {
 785                 parg = tp->args + i;
 786                 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name);
 787                 if (parg->count) {
 788                         pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s",
 789                                         parg->type->fmt);
 790                         for (j = 1; j < parg->count; j++)
 791                                 pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s",
 792                                                 parg->type->fmt);
 793                         pos += snprintf(buf + pos, LEN_OR_ZERO, "}");
 794                 } else
 795                         pos += snprintf(buf + pos, LEN_OR_ZERO, "%s",
 796                                         parg->type->fmt);
 797         }
 798
 799         pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
 800
 801         for (i = 0; i < tp->nr_args; i++) {
 802                 parg = tp->args + i;
 803                 if (parg->count) {
 804                         if (strcmp(parg->type->name, "string") == 0)
 805                                 fmt = ", __get_str(%s[%d])";
 806                         else
 807                                 fmt = ", REC->%s[%d]";
 808                         for (j = 0; j < parg->count; j++)
 809                                 pos += snprintf(buf + pos, LEN_OR_ZERO,
 810                                                 fmt, parg->name, j);
 811                 } else {
 812                         if (strcmp(parg->type->name, "string") == 0)
 813                                 fmt = ", __get_str(%s)";
 814                         else
 815                                 fmt = ", REC->%s";
 816                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 817                                         fmt, parg->name);
 818                 }
 819         }
 820
 821         /* return the length of print_fmt */
 822         return pos;
 823 }
 824 #undef LEN_OR_ZERO
 825
 826 int traceprobe_set_print_fmt(struct trace_probe *tp, bool is_return)
 827 {
 828         int len;
 829         char *print_fmt;
 830
 831         /* First: called with 0 length to calculate the needed length */
 832         len = __set_print_fmt(tp, NULL, 0, is_return);
 833         print_fmt = kmalloc(len + 1, GFP_KERNEL);
 834         if (!print_fmt)
 835                 return -ENOMEM;
 836
 837         /* Second: actually write the @print_fmt */
 838         __set_print_fmt(tp, print_fmt, len + 1, is_return);
 839         tp->call.print_fmt = print_fmt;
 840
 841         return 0;
 842 }
 843
 844 int traceprobe_define_arg_fields(struct trace_event_call *event_call,
 845                                  size_t offset, struct trace_probe *tp)
 846 {
 847         int ret, i;
 848
 849         /* Set argument names as fields */
 850         for (i = 0; i < tp->nr_args; i++) {
 851                 struct probe_arg *parg = &tp->args[i];
 852                 const char *fmt = parg->type->fmttype;
 853                 int size = parg->type->size;
 854
 855                 if (parg->fmt)
 856                         fmt = parg->fmt;
 857                 if (parg->count)
 858                         size *= parg->count;
 859                 ret = trace_define_field(event_call, fmt, parg->name,
 860                                          offset + parg->offset, size,
 861                                          parg->type->is_signed,
 862                                          FILTER_OTHER);
 863                 if (ret)
 864                         return ret;
 865         }
 866         return 0;
 867 }