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