kernel/trace/trace_probe.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Common code for probe-based Dynamic events.
   4  *
   5  * This code was copied from kernel/trace/trace_kprobe.c written by
   6  * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
   7  *
   8  * Updates to make this generic:
   9  * Copyright (C) IBM Corporation, 2010-2011
  10  * Author:     Srikar Dronamraju
  11  */
  12 #define pr_fmt(fmt)     "trace_probe: " fmt
  13
  14 #include "trace_probe.h"
  15
  16 #undef C
  17 #define C(a, b)         b
  18
  19 static const char *trace_probe_err_text[] = { ERRORS };
  20
  21 static const char *reserved_field_names[] = {
  22         "common_type",
  23         "common_flags",
  24         "common_preempt_count",
  25         "common_pid",
  26         "common_tgid",
  27         FIELD_STRING_IP,
  28         FIELD_STRING_RETIP,
  29         FIELD_STRING_FUNC,
  30 };
  31
  32 /* Printing  in basic type function template */
  33 #define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt)                  \
  34 int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\
  35 {                                                                       \
  36         trace_seq_printf(s, fmt, *(type *)data);                        \
  37         return !trace_seq_has_overflowed(s);                            \
  38 }                                                                       \
  39 const char PRINT_TYPE_FMT_NAME(tname)[] = fmt;
  40
  41 DEFINE_BASIC_PRINT_TYPE_FUNC(u8,  u8,  "%u")
  42 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
  43 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
  44 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
  45 DEFINE_BASIC_PRINT_TYPE_FUNC(s8,  s8,  "%d")
  46 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
  47 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
  48 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
  49 DEFINE_BASIC_PRINT_TYPE_FUNC(x8,  u8,  "0x%x")
  50 DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
  51 DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
  52 DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
  53
  54 int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent)
  55 {
  56         trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data);
  57         return !trace_seq_has_overflowed(s);
  58 }
  59 const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS";
  60
  61 /* Print type function for string type */
  62 int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)
  63 {
  64         int len = *(u32 *)data >> 16;
  65
  66         if (!len)
  67                 trace_seq_puts(s, "(fault)");
  68         else
  69                 trace_seq_printf(s, "\"%s\"",
  70                                  (const char *)get_loc_data(data, ent));
  71         return !trace_seq_has_overflowed(s);
  72 }
  73
  74 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
  75
  76 /* Fetch type information table */
  77 static const struct fetch_type probe_fetch_types[] = {
  78         /* Special types */
  79         __ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1,
  80                             "__data_loc char[]"),
  81         __ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1,
  82                             "__data_loc char[]"),
  83         /* Basic types */
  84         ASSIGN_FETCH_TYPE(u8,  u8,  0),
  85         ASSIGN_FETCH_TYPE(u16, u16, 0),
  86         ASSIGN_FETCH_TYPE(u32, u32, 0),
  87         ASSIGN_FETCH_TYPE(u64, u64, 0),
  88         ASSIGN_FETCH_TYPE(s8,  u8,  1),
  89         ASSIGN_FETCH_TYPE(s16, u16, 1),
  90         ASSIGN_FETCH_TYPE(s32, u32, 1),
  91         ASSIGN_FETCH_TYPE(s64, u64, 1),
  92         ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),
  93         ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
  94         ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
  95         ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
  96         ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0),
  97
  98         ASSIGN_FETCH_TYPE_END
  99 };
 100
 101 static const struct fetch_type *find_fetch_type(const char *type)
 102 {
 103         int i;
 104
 105         if (!type)
 106                 type = DEFAULT_FETCH_TYPE_STR;
 107
 108         /* Special case: bitfield */
 109         if (*type == 'b') {
 110                 unsigned long bs;
 111
 112                 type = strchr(type, '/');
 113                 if (!type)
 114                         goto fail;
 115
 116                 type++;
 117                 if (kstrtoul(type, 0, &bs))
 118                         goto fail;
 119
 120                 switch (bs) {
 121                 case 8:
 122                         return find_fetch_type("u8");
 123                 case 16:
 124                         return find_fetch_type("u16");
 125                 case 32:
 126                         return find_fetch_type("u32");
 127                 case 64:
 128                         return find_fetch_type("u64");
 129                 default:
 130                         goto fail;
 131                 }
 132         }
 133
 134         for (i = 0; probe_fetch_types[i].name; i++) {
 135                 if (strcmp(type, probe_fetch_types[i].name) == 0)
 136                         return &probe_fetch_types[i];
 137         }
 138
 139 fail:
 140         return NULL;
 141 }
 142
 143 static struct trace_probe_log trace_probe_log;
 144
 145 void trace_probe_log_init(const char *subsystem, int argc, const char **argv)
 146 {
 147         trace_probe_log.subsystem = subsystem;
 148         trace_probe_log.argc = argc;
 149         trace_probe_log.argv = argv;
 150         trace_probe_log.index = 0;
 151 }
 152
 153 void trace_probe_log_clear(void)
 154 {
 155         memset(&trace_probe_log, 0, sizeof(trace_probe_log));
 156 }
 157
 158 void trace_probe_log_set_index(int index)
 159 {
 160         trace_probe_log.index = index;
 161 }
 162
 163 void __trace_probe_log_err(int offset, int err_type)
 164 {
 165         char *command, *p;
 166         int i, len = 0, pos = 0;
 167
 168         if (!trace_probe_log.argv)
 169                 return;
 170
 171         /* Recalculate the length and allocate buffer */
 172         for (i = 0; i < trace_probe_log.argc; i++) {
 173                 if (i == trace_probe_log.index)
 174                         pos = len;
 175                 len += strlen(trace_probe_log.argv[i]) + 1;
 176         }
 177         command = kzalloc(len, GFP_KERNEL);
 178         if (!command)
 179                 return;
 180
 181         if (trace_probe_log.index >= trace_probe_log.argc) {
 182                 /**
 183                  * Set the error position is next to the last arg + space.
 184                  * Note that len includes the terminal null and the cursor
 185                  * appears at pos + 1.
 186                  */
 187                 pos = len;
 188                 offset = 0;
 189         }
 190
 191         /* And make a command string from argv array */
 192         p = command;
 193         for (i = 0; i < trace_probe_log.argc; i++) {
 194                 len = strlen(trace_probe_log.argv[i]);
 195                 strcpy(p, trace_probe_log.argv[i]);
 196                 p[len] = ' ';
 197                 p += len + 1;
 198         }
 199         *(p - 1) = '\0';
 200
 201         tracing_log_err(NULL, trace_probe_log.subsystem, command,
 202                         trace_probe_err_text, err_type, pos + offset);
 203
 204         kfree(command);
 205 }
 206
 207 /* Split symbol and offset. */
 208 int traceprobe_split_symbol_offset(char *symbol, long *offset)
 209 {
 210         char *tmp;
 211         int ret;
 212
 213         if (!offset)
 214                 return -EINVAL;
 215
 216         tmp = strpbrk(symbol, "+-");
 217         if (tmp) {
 218                 ret = kstrtol(tmp, 0, offset);
 219                 if (ret)
 220                         return ret;
 221                 *tmp = '\0';
 222         } else
 223                 *offset = 0;
 224
 225         return 0;
 226 }
 227
 228 /* @buf must has MAX_EVENT_NAME_LEN size */
 229 int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
 230                                 char *buf, int offset)
 231 {
 232         const char *slash, *event = *pevent;
 233         int len;
 234
 235         slash = strchr(event, '/');
 236         if (!slash)
 237                 slash = strchr(event, '.');
 238
 239         if (slash) {
 240                 if (slash == event) {
 241                         trace_probe_log_err(offset, NO_GROUP_NAME);
 242                         return -EINVAL;
 243                 }
 244                 if (slash - event + 1 > MAX_EVENT_NAME_LEN) {
 245                         trace_probe_log_err(offset, GROUP_TOO_LONG);
 246                         return -EINVAL;
 247                 }
 248                 strlcpy(buf, event, slash - event + 1);
 249                 if (!is_good_name(buf)) {
 250                         trace_probe_log_err(offset, BAD_GROUP_NAME);
 251                         return -EINVAL;
 252                 }
 253                 *pgroup = buf;
 254                 *pevent = slash + 1;
 255                 offset += slash - event + 1;
 256                 event = *pevent;
 257         }
 258         len = strlen(event);
 259         if (len == 0) {
 260                 trace_probe_log_err(offset, NO_EVENT_NAME);
 261                 return -EINVAL;
 262         } else if (len > MAX_EVENT_NAME_LEN) {
 263                 trace_probe_log_err(offset, EVENT_TOO_LONG);
 264                 return -EINVAL;
 265         }
 266         if (!is_good_name(event)) {
 267                 trace_probe_log_err(offset, BAD_EVENT_NAME);
 268                 return -EINVAL;
 269         }
 270         return 0;
 271 }
 272
 273 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
 274
 275 static int parse_probe_vars(char *arg, const struct fetch_type *t,
 276                         struct fetch_insn *code, unsigned int flags, int offs)
 277 {
 278         unsigned long param;
 279         int ret = 0;
 280         int len;
 281
 282         if (strcmp(arg, "retval") == 0) {
 283                 if (flags & TPARG_FL_RETURN) {
 284                         code->op = FETCH_OP_RETVAL;
 285                 } else {
 286                         trace_probe_log_err(offs, RETVAL_ON_PROBE);
 287                         ret = -EINVAL;
 288                 }
 289         } else if ((len = str_has_prefix(arg, "stack"))) {
 290                 if (arg[len] == '\0') {
 291                         code->op = FETCH_OP_STACKP;
 292                 } else if (isdigit(arg[len])) {
 293                         ret = kstrtoul(arg + len, 10, &param);
 294                         if (ret) {
 295                                 goto inval_var;
 296                         } else if ((flags & TPARG_FL_KERNEL) &&
 297                                     param > PARAM_MAX_STACK) {
 298                                 trace_probe_log_err(offs, BAD_STACK_NUM);
 299                                 ret = -EINVAL;
 300                         } else {
 301                                 code->op = FETCH_OP_STACK;
 302                                 code->param = (unsigned int)param;
 303                         }
 304                 } else
 305                         goto inval_var;
 306         } else if (strcmp(arg, "comm") == 0) {
 307                 code->op = FETCH_OP_COMM;
 308 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
 309         } else if (((flags & TPARG_FL_MASK) ==
 310                     (TPARG_FL_KERNEL | TPARG_FL_FENTRY)) &&
 311                    (len = str_has_prefix(arg, "arg"))) {
 312                 ret = kstrtoul(arg + len, 10, &param);
 313                 if (ret) {
 314                         goto inval_var;
 315                 } else if (!param || param > PARAM_MAX_STACK) {
 316                         trace_probe_log_err(offs, BAD_ARG_NUM);
 317                         return -EINVAL;
 318                 }
 319                 code->op = FETCH_OP_ARG;
 320                 code->param = (unsigned int)param - 1;
 321 #endif
 322         } else if (flags & TPARG_FL_TPOINT) {
 323                 if (code->data)
 324                         return -EFAULT;
 325                 code->data = kstrdup(arg, GFP_KERNEL);
 326                 if (!code->data)
 327                         return -ENOMEM;
 328                 code->op = FETCH_OP_TP_ARG;
 329         } else
 330                 goto inval_var;
 331
 332         return ret;
 333
 334 inval_var:
 335         trace_probe_log_err(offs, BAD_VAR);
 336         return -EINVAL;
 337 }
 338
 339 static int str_to_immediate(char *str, unsigned long *imm)
 340 {
 341         if (isdigit(str[0]))
 342                 return kstrtoul(str, 0, imm);
 343         else if (str[0] == '-')
 344                 return kstrtol(str, 0, (long *)imm);
 345         else if (str[0] == '+')
 346                 return kstrtol(str + 1, 0, (long *)imm);
 347         return -EINVAL;
 348 }
 349
 350 static int __parse_imm_string(char *str, char **pbuf, int offs)
 351 {
 352         size_t len = strlen(str);
 353
 354         if (str[len - 1] != '"') {
 355                 trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE);
 356                 return -EINVAL;
 357         }
 358         *pbuf = kstrndup(str, len - 1, GFP_KERNEL);
 359         if (!*pbuf)
 360                 return -ENOMEM;
 361         return 0;
 362 }
 363
 364 /* Recursive argument parser */
 365 static int
 366 parse_probe_arg(char *arg, const struct fetch_type *type,
 367                 struct fetch_insn **pcode, struct fetch_insn *end,
 368                 unsigned int flags, int offs)
 369 {
 370         struct fetch_insn *code = *pcode;
 371         unsigned long param;
 372         int deref = FETCH_OP_DEREF;
 373         long offset = 0;
 374         char *tmp;
 375         int ret = 0;
 376
 377         switch (arg[0]) {
 378         case '$':
 379                 ret = parse_probe_vars(arg + 1, type, code, flags, offs);
 380                 break;
 381
 382         case '%':       /* named register */
 383                 ret = regs_query_register_offset(arg + 1);
 384                 if (ret >= 0) {
 385                         code->op = FETCH_OP_REG;
 386                         code->param = (unsigned int)ret;
 387                         ret = 0;
 388                 } else
 389                         trace_probe_log_err(offs, BAD_REG_NAME);
 390                 break;
 391
 392         case '@':       /* memory, file-offset or symbol */
 393                 if (isdigit(arg[1])) {
 394                         ret = kstrtoul(arg + 1, 0, &param);
 395                         if (ret) {
 396                                 trace_probe_log_err(offs, BAD_MEM_ADDR);
 397                                 break;
 398                         }
 399                         /* load address */
 400                         code->op = FETCH_OP_IMM;
 401                         code->immediate = param;
 402                 } else if (arg[1] == '+') {
 403                         /* kprobes don't support file offsets */
 404                         if (flags & TPARG_FL_KERNEL) {
 405                                 trace_probe_log_err(offs, FILE_ON_KPROBE);
 406                                 return -EINVAL;
 407                         }
 408                         ret = kstrtol(arg + 2, 0, &offset);
 409                         if (ret) {
 410                                 trace_probe_log_err(offs, BAD_FILE_OFFS);
 411                                 break;
 412                         }
 413
 414                         code->op = FETCH_OP_FOFFS;
 415                         code->immediate = (unsigned long)offset;  // imm64?
 416                 } else {
 417                         /* uprobes don't support symbols */
 418                         if (!(flags & TPARG_FL_KERNEL)) {
 419                                 trace_probe_log_err(offs, SYM_ON_UPROBE);
 420                                 return -EINVAL;
 421                         }
 422                         /* Preserve symbol for updating */
 423                         code->op = FETCH_NOP_SYMBOL;
 424                         code->data = kstrdup(arg + 1, GFP_KERNEL);
 425                         if (!code->data)
 426                                 return -ENOMEM;
 427                         if (++code == end) {
 428                                 trace_probe_log_err(offs, TOO_MANY_OPS);
 429                                 return -EINVAL;
 430                         }
 431                         code->op = FETCH_OP_IMM;
 432                         code->immediate = 0;
 433                 }
 434                 /* These are fetching from memory */
 435                 if (++code == end) {
 436                         trace_probe_log_err(offs, TOO_MANY_OPS);
 437                         return -EINVAL;
 438                 }
 439                 *pcode = code;
 440                 code->op = FETCH_OP_DEREF;
 441                 code->offset = offset;
 442                 break;
 443
 444         case '+':       /* deref memory */
 445         case '-':
 446                 if (arg[1] == 'u') {
 447                         deref = FETCH_OP_UDEREF;
 448                         arg[1] = arg[0];
 449                         arg++;
 450                 }
 451                 if (arg[0] == '+')
 452                         arg++;  /* Skip '+', because kstrtol() rejects it. */
 453                 tmp = strchr(arg, '(');
 454                 if (!tmp) {
 455                         trace_probe_log_err(offs, DEREF_NEED_BRACE);
 456                         return -EINVAL;
 457                 }
 458                 *tmp = '\0';
 459                 ret = kstrtol(arg, 0, &offset);
 460                 if (ret) {
 461                         trace_probe_log_err(offs, BAD_DEREF_OFFS);
 462                         break;
 463                 }
 464                 offs += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
 465                 arg = tmp + 1;
 466                 tmp = strrchr(arg, ')');
 467                 if (!tmp) {
 468                         trace_probe_log_err(offs + strlen(arg),
 469                                             DEREF_OPEN_BRACE);
 470                         return -EINVAL;
 471                 } else {
 472                         const struct fetch_type *t2 = find_fetch_type(NULL);
 473
 474                         *tmp = '\0';
 475                         ret = parse_probe_arg(arg, t2, &code, end, flags, offs);
 476                         if (ret)
 477                                 break;
 478                         if (code->op == FETCH_OP_COMM ||
 479                             code->op == FETCH_OP_DATA) {
 480                                 trace_probe_log_err(offs, COMM_CANT_DEREF);
 481                                 return -EINVAL;
 482                         }
 483                         if (++code == end) {
 484                                 trace_probe_log_err(offs, TOO_MANY_OPS);
 485                                 return -EINVAL;
 486                         }
 487                         *pcode = code;
 488
 489                         code->op = deref;
 490                         code->offset = offset;
 491                 }
 492                 break;
 493         case '\\':      /* Immediate value */
 494                 if (arg[1] == '"') {    /* Immediate string */
 495                         ret = __parse_imm_string(arg + 2, &tmp, offs + 2);
 496                         if (ret)
 497                                 break;
 498                         code->op = FETCH_OP_DATA;
 499                         code->data = tmp;
 500                 } else {
 501                         ret = str_to_immediate(arg + 1, &code->immediate);
 502                         if (ret)
 503                                 trace_probe_log_err(offs + 1, BAD_IMM);
 504                         else
 505                                 code->op = FETCH_OP_IMM;
 506                 }
 507                 break;
 508         }
 509         if (!ret && code->op == FETCH_OP_NOP) {
 510                 /* Parsed, but do not find fetch method */
 511                 trace_probe_log_err(offs, BAD_FETCH_ARG);
 512                 ret = -EINVAL;
 513         }
 514         return ret;
 515 }
 516
 517 #define BYTES_TO_BITS(nb)       ((BITS_PER_LONG * (nb)) / sizeof(long))
 518
 519 /* Bitfield type needs to be parsed into a fetch function */
 520 static int __parse_bitfield_probe_arg(const char *bf,
 521                                       const struct fetch_type *t,
 522                                       struct fetch_insn **pcode)
 523 {
 524         struct fetch_insn *code = *pcode;
 525         unsigned long bw, bo;
 526         char *tail;
 527
 528         if (*bf != 'b')
 529                 return 0;
 530
 531         bw = simple_strtoul(bf + 1, &tail, 0);  /* Use simple one */
 532
 533         if (bw == 0 || *tail != '@')
 534                 return -EINVAL;
 535
 536         bf = tail + 1;
 537         bo = simple_strtoul(bf, &tail, 0);
 538
 539         if (tail == bf || *tail != '/')
 540                 return -EINVAL;
 541         code++;
 542         if (code->op != FETCH_OP_NOP)
 543                 return -EINVAL;
 544         *pcode = code;
 545
 546         code->op = FETCH_OP_MOD_BF;
 547         code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
 548         code->rshift = BYTES_TO_BITS(t->size) - bw;
 549         code->basesize = t->size;
 550
 551         return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
 552 }
 553
 554 /* String length checking wrapper */
 555 static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
 556                 struct probe_arg *parg, unsigned int flags, int offset)
 557 {
 558         struct fetch_insn *code, *scode, *tmp = NULL;
 559         char *t, *t2, *t3;
 560         char *arg;
 561         int ret, len;
 562
 563         arg = kstrdup(argv, GFP_KERNEL);
 564         if (!arg)
 565                 return -ENOMEM;
 566
 567         ret = -EINVAL;
 568         len = strlen(arg);
 569         if (len > MAX_ARGSTR_LEN) {
 570                 trace_probe_log_err(offset, ARG_TOO_LONG);
 571                 goto out;
 572         } else if (len == 0) {
 573                 trace_probe_log_err(offset, NO_ARG_BODY);
 574                 goto out;
 575         }
 576
 577         ret = -ENOMEM;
 578         parg->comm = kstrdup(arg, GFP_KERNEL);
 579         if (!parg->comm)
 580                 goto out;
 581
 582         ret = -EINVAL;
 583         t = strchr(arg, ':');
 584         if (t) {
 585                 *t = '\0';
 586                 t2 = strchr(++t, '[');
 587                 if (t2) {
 588                         *t2++ = '\0';
 589                         t3 = strchr(t2, ']');
 590                         if (!t3) {
 591                                 offset += t2 + strlen(t2) - arg;
 592                                 trace_probe_log_err(offset,
 593                                                     ARRAY_NO_CLOSE);
 594                                 goto out;
 595                         } else if (t3[1] != '\0') {
 596                                 trace_probe_log_err(offset + t3 + 1 - arg,
 597                                                     BAD_ARRAY_SUFFIX);
 598                                 goto out;
 599                         }
 600                         *t3 = '\0';
 601                         if (kstrtouint(t2, 0, &parg->count) || !parg->count) {
 602                                 trace_probe_log_err(offset + t2 - arg,
 603                                                     BAD_ARRAY_NUM);
 604                                 goto out;
 605                         }
 606                         if (parg->count > MAX_ARRAY_LEN) {
 607                                 trace_probe_log_err(offset + t2 - arg,
 608                                                     ARRAY_TOO_BIG);
 609                                 goto out;
 610                         }
 611                 }
 612         }
 613
 614         /*
 615          * Since $comm and immediate string can not be dereferenced,
 616          * we can find those by strcmp.
 617          */
 618         if (strcmp(arg, "$comm") == 0 || strncmp(arg, "\\\"", 2) == 0) {
 619                 /* The type of $comm must be "string", and not an array. */
 620                 if (parg->count || (t && strcmp(t, "string")))
 621                         goto out;
 622                 parg->type = find_fetch_type("string");
 623         } else
 624                 parg->type = find_fetch_type(t);
 625         if (!parg->type) {
 626                 trace_probe_log_err(offset + (t ? (t - arg) : 0), BAD_TYPE);
 627                 goto out;
 628         }
 629         parg->offset = *size;
 630         *size += parg->type->size * (parg->count ?: 1);
 631
 632         ret = -ENOMEM;
 633         if (parg->count) {
 634                 len = strlen(parg->type->fmttype) + 6;
 635                 parg->fmt = kmalloc(len, GFP_KERNEL);
 636                 if (!parg->fmt)
 637                         goto out;
 638                 snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
 639                          parg->count);
 640         }
 641
 642         code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
 643         if (!code)
 644                 goto out;
 645         code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
 646
 647         ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
 648                               flags, offset);
 649         if (ret)
 650                 goto fail;
 651
 652         ret = -EINVAL;
 653         /* Store operation */
 654         if (!strcmp(parg->type->name, "string") ||
 655             !strcmp(parg->type->name, "ustring")) {
 656                 if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF &&
 657                     code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM &&
 658                     code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) {
 659                         trace_probe_log_err(offset + (t ? (t - arg) : 0),
 660                                             BAD_STRING);
 661                         goto fail;
 662                 }
 663                 if ((code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM ||
 664                      code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG ||
 665                      parg->count) {
 666                         /*
 667                          * IMM, DATA and COMM is pointing actual address, those
 668                          * must be kept, and if parg->count != 0, this is an
 669                          * array of string pointers instead of string address
 670                          * itself.
 671                          */
 672                         code++;
 673                         if (code->op != FETCH_OP_NOP) {
 674                                 trace_probe_log_err(offset, TOO_MANY_OPS);
 675                                 goto fail;
 676                         }
 677                 }
 678                 /* If op == DEREF, replace it with STRING */
 679                 if (!strcmp(parg->type->name, "ustring") ||
 680                     code->op == FETCH_OP_UDEREF)
 681                         code->op = FETCH_OP_ST_USTRING;
 682                 else
 683                         code->op = FETCH_OP_ST_STRING;
 684                 code->size = parg->type->size;
 685                 parg->dynamic = true;
 686         } else if (code->op == FETCH_OP_DEREF) {
 687                 code->op = FETCH_OP_ST_MEM;
 688                 code->size = parg->type->size;
 689         } else if (code->op == FETCH_OP_UDEREF) {
 690                 code->op = FETCH_OP_ST_UMEM;
 691                 code->size = parg->type->size;
 692         } else {
 693                 code++;
 694                 if (code->op != FETCH_OP_NOP) {
 695                         trace_probe_log_err(offset, TOO_MANY_OPS);
 696                         goto fail;
 697                 }
 698                 code->op = FETCH_OP_ST_RAW;
 699                 code->size = parg->type->size;
 700         }
 701         scode = code;
 702         /* Modify operation */
 703         if (t != NULL) {
 704                 ret = __parse_bitfield_probe_arg(t, parg->type, &code);
 705                 if (ret) {
 706                         trace_probe_log_err(offset + t - arg, BAD_BITFIELD);
 707                         goto fail;
 708                 }
 709         }
 710         ret = -EINVAL;
 711         /* Loop(Array) operation */
 712         if (parg->count) {
 713                 if (scode->op != FETCH_OP_ST_MEM &&
 714                     scode->op != FETCH_OP_ST_STRING &&
 715                     scode->op != FETCH_OP_ST_USTRING) {
 716                         trace_probe_log_err(offset + (t ? (t - arg) : 0),
 717                                             BAD_STRING);
 718                         goto fail;
 719                 }
 720                 code++;
 721                 if (code->op != FETCH_OP_NOP) {
 722                         trace_probe_log_err(offset, TOO_MANY_OPS);
 723                         goto fail;
 724                 }
 725                 code->op = FETCH_OP_LP_ARRAY;
 726                 code->param = parg->count;
 727         }
 728         code++;
 729         code->op = FETCH_OP_END;
 730
 731         ret = 0;
 732         /* Shrink down the code buffer */
 733         parg->code = kcalloc(code - tmp + 1, sizeof(*code), GFP_KERNEL);
 734         if (!parg->code)
 735                 ret = -ENOMEM;
 736         else
 737                 memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
 738
 739 fail:
 740         if (ret) {
 741                 for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
 742                         if (code->op == FETCH_NOP_SYMBOL ||
 743                             code->op == FETCH_OP_DATA)
 744                                 kfree(code->data);
 745         }
 746         kfree(tmp);
 747 out:
 748         kfree(arg);
 749
 750         return ret;
 751 }
 752
 753 /* Return 1 if name is reserved or already used by another argument */
 754 static int traceprobe_conflict_field_name(const char *name,
 755                                           struct probe_arg *args, int narg)
 756 {
 757         int i;
 758
 759         for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
 760                 if (strcmp(reserved_field_names[i], name) == 0)
 761                         return 1;
 762
 763         for (i = 0; i < narg; i++)
 764                 if (strcmp(args[i].name, name) == 0)
 765                         return 1;
 766
 767         return 0;
 768 }
 769
 770 int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg,
 771                                 unsigned int flags)
 772 {
 773         struct probe_arg *parg = &tp->args[i];
 774         const char *body;
 775
 776         /* Increment count for freeing args in error case */
 777         tp->nr_args++;
 778
 779         body = strchr(arg, '=');
 780         if (body) {
 781                 if (body - arg > MAX_ARG_NAME_LEN) {
 782                         trace_probe_log_err(0, ARG_NAME_TOO_LONG);
 783                         return -EINVAL;
 784                 } else if (body == arg) {
 785                         trace_probe_log_err(0, NO_ARG_NAME);
 786                         return -EINVAL;
 787                 }
 788                 parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
 789                 body++;
 790         } else {
 791                 /* If argument name is omitted, set "argN" */
 792                 parg->name = kasprintf(GFP_KERNEL, "arg%d", i + 1);
 793                 body = arg;
 794         }
 795         if (!parg->name)
 796                 return -ENOMEM;
 797
 798         if (!is_good_name(parg->name)) {
 799                 trace_probe_log_err(0, BAD_ARG_NAME);
 800                 return -EINVAL;
 801         }
 802         if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
 803                 trace_probe_log_err(0, USED_ARG_NAME);
 804                 return -EINVAL;
 805         }
 806         /* Parse fetch argument */
 807         return traceprobe_parse_probe_arg_body(body, &tp->size, parg, flags,
 808                                                body - arg);
 809 }
 810
 811 void traceprobe_free_probe_arg(struct probe_arg *arg)
 812 {
 813         struct fetch_insn *code = arg->code;
 814
 815         while (code && code->op != FETCH_OP_END) {
 816                 if (code->op == FETCH_NOP_SYMBOL ||
 817                     code->op == FETCH_OP_DATA)
 818                         kfree(code->data);
 819                 code++;
 820         }
 821         kfree(arg->code);
 822         kfree(arg->name);
 823         kfree(arg->comm);
 824         kfree(arg->fmt);
 825 }
 826
 827 int traceprobe_update_arg(struct probe_arg *arg)
 828 {
 829         struct fetch_insn *code = arg->code;
 830         long offset;
 831         char *tmp;
 832         char c;
 833         int ret = 0;
 834
 835         while (code && code->op != FETCH_OP_END) {
 836                 if (code->op == FETCH_NOP_SYMBOL) {
 837                         if (code[1].op != FETCH_OP_IMM)
 838                                 return -EINVAL;
 839
 840                         tmp = strpbrk(code->data, "+-");
 841                         if (tmp)
 842                                 c = *tmp;
 843                         ret = traceprobe_split_symbol_offset(code->data,
 844                                                              &offset);
 845                         if (ret)
 846                                 return ret;
 847
 848                         code[1].immediate =
 849                                 (unsigned long)kallsyms_lookup_name(code->data);
 850                         if (tmp)
 851                                 *tmp = c;
 852                         if (!code[1].immediate)
 853                                 return -ENOENT;
 854                         code[1].immediate += offset;
 855                 }
 856                 code++;
 857         }
 858         return 0;
 859 }
 860
 861 /* When len=0, we just calculate the needed length */
 862 #define LEN_OR_ZERO (len ? len - pos : 0)
 863 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
 864                            enum probe_print_type ptype)
 865 {
 866         struct probe_arg *parg;
 867         int i, j;
 868         int pos = 0;
 869         const char *fmt, *arg;
 870
 871         switch (ptype) {
 872         case PROBE_PRINT_NORMAL:
 873                 fmt = "(%lx)";
 874                 arg = ", REC->" FIELD_STRING_IP;
 875                 break;
 876         case PROBE_PRINT_RETURN:
 877                 fmt = "(%lx <- %lx)";
 878                 arg = ", REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
 879                 break;
 880         case PROBE_PRINT_EVENT:
 881                 fmt = "";
 882                 arg = "";
 883                 break;
 884         default:
 885                 WARN_ON_ONCE(1);
 886                 return 0;
 887         }
 888
 889         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
 890
 891         for (i = 0; i < tp->nr_args; i++) {
 892                 parg = tp->args + i;
 893                 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name);
 894                 if (parg->count) {
 895                         pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s",
 896                                         parg->type->fmt);
 897                         for (j = 1; j < parg->count; j++)
 898                                 pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s",
 899                                                 parg->type->fmt);
 900                         pos += snprintf(buf + pos, LEN_OR_ZERO, "}");
 901                 } else
 902                         pos += snprintf(buf + pos, LEN_OR_ZERO, "%s",
 903                                         parg->type->fmt);
 904         }
 905
 906         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", arg);
 907
 908         for (i = 0; i < tp->nr_args; i++) {
 909                 parg = tp->args + i;
 910                 if (parg->count) {
 911                         if ((strcmp(parg->type->name, "string") == 0) ||
 912                             (strcmp(parg->type->name, "ustring") == 0))
 913                                 fmt = ", __get_str(%s[%d])";
 914                         else
 915                                 fmt = ", REC->%s[%d]";
 916                         for (j = 0; j < parg->count; j++)
 917                                 pos += snprintf(buf + pos, LEN_OR_ZERO,
 918                                                 fmt, parg->name, j);
 919                 } else {
 920                         if ((strcmp(parg->type->name, "string") == 0) ||
 921                             (strcmp(parg->type->name, "ustring") == 0))
 922                                 fmt = ", __get_str(%s)";
 923                         else
 924                                 fmt = ", REC->%s";
 925                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 926                                         fmt, parg->name);
 927                 }
 928         }
 929
 930         /* return the length of print_fmt */
 931         return pos;
 932 }
 933 #undef LEN_OR_ZERO
 934
 935 int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype)
 936 {
 937         struct trace_event_call *call = trace_probe_event_call(tp);
 938         int len;
 939         char *print_fmt;
 940
 941         /* First: called with 0 length to calculate the needed length */
 942         len = __set_print_fmt(tp, NULL, 0, ptype);
 943         print_fmt = kmalloc(len + 1, GFP_KERNEL);
 944         if (!print_fmt)
 945                 return -ENOMEM;
 946
 947         /* Second: actually write the @print_fmt */
 948         __set_print_fmt(tp, print_fmt, len + 1, ptype);
 949         call->print_fmt = print_fmt;
 950
 951         return 0;
 952 }
 953
 954 int traceprobe_define_arg_fields(struct trace_event_call *event_call,
 955                                  size_t offset, struct trace_probe *tp)
 956 {
 957         int ret, i;
 958
 959         /* Set argument names as fields */
 960         for (i = 0; i < tp->nr_args; i++) {
 961                 struct probe_arg *parg = &tp->args[i];
 962                 const char *fmt = parg->type->fmttype;
 963                 int size = parg->type->size;
 964
 965                 if (parg->fmt)
 966                         fmt = parg->fmt;
 967                 if (parg->count)
 968                         size *= parg->count;
 969                 ret = trace_define_field(event_call, fmt, parg->name,
 970                                          offset + parg->offset, size,
 971                                          parg->type->is_signed,
 972                                          FILTER_OTHER);
 973                 if (ret)
 974                         return ret;
 975         }
 976         return 0;
 977 }
 978
 979 static void trace_probe_event_free(struct trace_probe_event *tpe)
 980 {
 981         kfree(tpe->class.system);
 982         kfree(tpe->call.name);
 983         kfree(tpe->call.print_fmt);
 984         kfree(tpe);
 985 }
 986
 987 int trace_probe_append(struct trace_probe *tp, struct trace_probe *to)
 988 {
 989         if (trace_probe_has_sibling(tp))
 990                 return -EBUSY;
 991
 992         list_del_init(&tp->list);
 993         trace_probe_event_free(tp->event);
 994
 995         tp->event = to->event;
 996         list_add_tail(&tp->list, trace_probe_probe_list(to));
 997
 998         return 0;
 999 }
1000
1001 void trace_probe_unlink(struct trace_probe *tp)
1002 {
1003         list_del_init(&tp->list);
1004         if (list_empty(trace_probe_probe_list(tp)))
1005                 trace_probe_event_free(tp->event);
1006         tp->event = NULL;
1007 }
1008
1009 void trace_probe_cleanup(struct trace_probe *tp)
1010 {
1011         int i;
1012
1013         for (i = 0; i < tp->nr_args; i++)
1014                 traceprobe_free_probe_arg(&tp->args[i]);
1015
1016         if (tp->event)
1017                 trace_probe_unlink(tp);
1018 }
1019
1020 int trace_probe_init(struct trace_probe *tp, const char *event,
1021                      const char *group, bool alloc_filter)
1022 {
1023         struct trace_event_call *call;
1024         size_t size = sizeof(struct trace_probe_event);
1025         int ret = 0;
1026
1027         if (!event || !group)
1028                 return -EINVAL;
1029
1030         if (alloc_filter)
1031                 size += sizeof(struct trace_uprobe_filter);
1032
1033         tp->event = kzalloc(size, GFP_KERNEL);
1034         if (!tp->event)
1035                 return -ENOMEM;
1036
1037         INIT_LIST_HEAD(&tp->event->files);
1038         INIT_LIST_HEAD(&tp->event->class.fields);
1039         INIT_LIST_HEAD(&tp->event->probes);
1040         INIT_LIST_HEAD(&tp->list);
1041         list_add(&tp->list, &tp->event->probes);
1042
1043         call = trace_probe_event_call(tp);
1044         call->class = &tp->event->class;
1045         call->name = kstrdup(event, GFP_KERNEL);
1046         if (!call->name) {
1047                 ret = -ENOMEM;
1048                 goto error;
1049         }
1050
1051         tp->event->class.system = kstrdup(group, GFP_KERNEL);
1052         if (!tp->event->class.system) {
1053                 ret = -ENOMEM;
1054                 goto error;
1055         }
1056
1057         return 0;
1058
1059 error:
1060         trace_probe_cleanup(tp);
1061         return ret;
1062 }
1063
1064 static struct trace_event_call *
1065 find_trace_event_call(const char *system, const char *event_name)
1066 {
1067         struct trace_event_call *tp_event;
1068         const char *name;
1069
1070         list_for_each_entry(tp_event, &ftrace_events, list) {
1071                 if (!tp_event->class->system ||
1072                     strcmp(system, tp_event->class->system))
1073                         continue;
1074                 name = trace_event_name(tp_event);
1075                 if (!name || strcmp(event_name, name))
1076                         continue;
1077                 return tp_event;
1078         }
1079
1080         return NULL;
1081 }
1082
1083 int trace_probe_register_event_call(struct trace_probe *tp)
1084 {
1085         struct trace_event_call *call = trace_probe_event_call(tp);
1086         int ret;
1087
1088         lockdep_assert_held(&event_mutex);
1089
1090         if (find_trace_event_call(trace_probe_group_name(tp),
1091                                   trace_probe_name(tp)))
1092                 return -EEXIST;
1093
1094         ret = register_trace_event(&call->event);
1095         if (!ret)
1096                 return -ENODEV;
1097
1098         ret = trace_add_event_call(call);
1099         if (ret)
1100                 unregister_trace_event(&call->event);
1101
1102         return ret;
1103 }
1104
1105 int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file)
1106 {
1107         struct event_file_link *link;
1108
1109         link = kmalloc(sizeof(*link), GFP_KERNEL);
1110         if (!link)
1111                 return -ENOMEM;
1112
1113         link->file = file;
1114         INIT_LIST_HEAD(&link->list);
1115         list_add_tail_rcu(&link->list, &tp->event->files);
1116         trace_probe_set_flag(tp, TP_FLAG_TRACE);
1117         return 0;
1118 }
1119
1120 struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
1121                                                   struct trace_event_file *file)
1122 {
1123         struct event_file_link *link;
1124
1125         trace_probe_for_each_link(link, tp) {
1126                 if (link->file == file)
1127                         return link;
1128         }
1129
1130         return NULL;
1131 }
1132
1133 int trace_probe_remove_file(struct trace_probe *tp,
1134                             struct trace_event_file *file)
1135 {
1136         struct event_file_link *link;
1137
1138         link = trace_probe_get_file_link(tp, file);
1139         if (!link)
1140                 return -ENOENT;
1141
1142         list_del_rcu(&link->list);
1143         kvfree_rcu(link);
1144
1145         if (list_empty(&tp->event->files))
1146                 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
1147
1148         return 0;
1149 }
1150
1151 /*
1152  * Return the smallest index of different type argument (start from 1).
1153  * If all argument types and name are same, return 0.
1154  */
1155 int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
1156 {
1157         int i;
1158
1159         /* In case of more arguments */
1160         if (a->nr_args < b->nr_args)
1161                 return a->nr_args + 1;
1162         if (a->nr_args > b->nr_args)
1163                 return b->nr_args + 1;
1164
1165         for (i = 0; i < a->nr_args; i++) {
1166                 if ((b->nr_args <= i) ||
1167                     ((a->args[i].type != b->args[i].type) ||
1168                      (a->args[i].count != b->args[i].count) ||
1169                      strcmp(a->args[i].name, b->args[i].name)))
1170                         return i + 1;
1171         }
1172
1173         return 0;
1174 }
1175
1176 bool trace_probe_match_command_args(struct trace_probe *tp,
1177                                     int argc, const char **argv)
1178 {
1179         char buf[MAX_ARGSTR_LEN + 1];
1180         int i;
1181
1182         if (tp->nr_args < argc)
1183                 return false;
1184
1185         for (i = 0; i < argc; i++) {
1186                 snprintf(buf, sizeof(buf), "%s=%s",
1187                          tp->args[i].name, tp->args[i].comm);
1188                 if (strcmp(buf, argv[i]))
1189                         return false;
1190         }
1191         return true;
1192 }
1193
1194 int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **))
1195 {
1196         int argc = 0, ret = 0;
1197         char **argv;
1198
1199         argv = argv_split(GFP_KERNEL, raw_command, &argc);
1200         if (!argv)
1201                 return -ENOMEM;
1202
1203         if (argc)
1204                 ret = createfn(argc, (const char **)argv);
1205
1206         argv_free(argv);
1207
1208         return ret;
1209 }