kernel/trace/trace_probe.c

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