kernel/trace/trace_probe.c

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