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 static const char *reserved_field_names[] = { 17 "common_type", 18 "common_flags", 19 "common_preempt_count", 20 "common_pid", 21 "common_tgid", 22 FIELD_STRING_IP, 23 FIELD_STRING_RETIP, 24 FIELD_STRING_FUNC, 25 }; 26 27 /* Printing in basic type function template */ 28 #define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt) \ 29 int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\ 30 { \ 31 trace_seq_printf(s, fmt, *(type *)data); \ 32 return !trace_seq_has_overflowed(s); \ 33 } \ 34 const char PRINT_TYPE_FMT_NAME(tname)[] = fmt; 35 36 DEFINE_BASIC_PRINT_TYPE_FUNC(u8, u8, "%u") 37 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u") 38 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u") 39 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu") 40 DEFINE_BASIC_PRINT_TYPE_FUNC(s8, s8, "%d") 41 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d") 42 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d") 43 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld") 44 DEFINE_BASIC_PRINT_TYPE_FUNC(x8, u8, "0x%x") 45 DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x") 46 DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x") 47 DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx") 48 49 int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent) 50 { 51 trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data); 52 return !trace_seq_has_overflowed(s); 53 } 54 const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS"; 55 56 /* Print type function for string type */ 57 int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent) 58 { 59 int len = *(u32 *)data >> 16; 60 61 if (!len) 62 trace_seq_puts(s, "(fault)"); 63 else 64 trace_seq_printf(s, "\"%s\"", 65 (const char *)get_loc_data(data, ent)); 66 return !trace_seq_has_overflowed(s); 67 } 68 69 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\""; 70 71 /* Fetch type information table */ 72 static const struct fetch_type probe_fetch_types[] = { 73 /* Special types */ 74 __ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1, 75 "__data_loc char[]"), 76 /* Basic types */ 77 ASSIGN_FETCH_TYPE(u8, u8, 0), 78 ASSIGN_FETCH_TYPE(u16, u16, 0), 79 ASSIGN_FETCH_TYPE(u32, u32, 0), 80 ASSIGN_FETCH_TYPE(u64, u64, 0), 81 ASSIGN_FETCH_TYPE(s8, u8, 1), 82 ASSIGN_FETCH_TYPE(s16, u16, 1), 83 ASSIGN_FETCH_TYPE(s32, u32, 1), 84 ASSIGN_FETCH_TYPE(s64, u64, 1), 85 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0), 86 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0), 87 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0), 88 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0), 89 ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0), 90 91 ASSIGN_FETCH_TYPE_END 92 }; 93 94 static const struct fetch_type *find_fetch_type(const char *type) 95 { 96 int i; 97 98 if (!type) 99 type = DEFAULT_FETCH_TYPE_STR; 100 101 /* Special case: bitfield */ 102 if (*type == 'b') { 103 unsigned long bs; 104 105 type = strchr(type, '/'); 106 if (!type) 107 goto fail; 108 109 type++; 110 if (kstrtoul(type, 0, &bs)) 111 goto fail; 112 113 switch (bs) { 114 case 8: 115 return find_fetch_type("u8"); 116 case 16: 117 return find_fetch_type("u16"); 118 case 32: 119 return find_fetch_type("u32"); 120 case 64: 121 return find_fetch_type("u64"); 122 default: 123 goto fail; 124 } 125 } 126 127 for (i = 0; probe_fetch_types[i].name; i++) { 128 if (strcmp(type, probe_fetch_types[i].name) == 0) 129 return &probe_fetch_types[i]; 130 } 131 132 fail: 133 return NULL; 134 } 135 136 /* Split symbol and offset. */ 137 int traceprobe_split_symbol_offset(char *symbol, long *offset) 138 { 139 char *tmp; 140 int ret; 141 142 if (!offset) 143 return -EINVAL; 144 145 tmp = strpbrk(symbol, "+-"); 146 if (tmp) { 147 ret = kstrtol(tmp, 0, offset); 148 if (ret) 149 return ret; 150 *tmp = '\0'; 151 } else 152 *offset = 0; 153 154 return 0; 155 } 156 157 /* @buf must has MAX_EVENT_NAME_LEN size */ 158 int traceprobe_parse_event_name(const char **pevent, const char **pgroup, 159 char *buf) 160 { 161 const char *slash, *event = *pevent; 162 int len; 163 164 slash = strchr(event, '/'); 165 if (slash) { 166 if (slash == event) { 167 pr_info("Group name is not specified\n"); 168 return -EINVAL; 169 } 170 if (slash - event + 1 > MAX_EVENT_NAME_LEN) { 171 pr_info("Group name is too long\n"); 172 return -E2BIG; 173 } 174 strlcpy(buf, event, slash - event + 1); 175 if (!is_good_name(buf)) { 176 pr_info("Group name must follow the same rules as C identifiers\n"); 177 return -EINVAL; 178 } 179 *pgroup = buf; 180 *pevent = slash + 1; 181 event = *pevent; 182 } 183 len = strlen(event); 184 if (len == 0) { 185 pr_info("Event name is not specified\n"); 186 return -EINVAL; 187 } else if (len > MAX_EVENT_NAME_LEN) { 188 pr_info("Event name is too long\n"); 189 return -E2BIG; 190 } 191 if (!is_good_name(event)) { 192 pr_info("Event name must follow the same rules as C identifiers\n"); 193 return -EINVAL; 194 } 195 return 0; 196 } 197 198 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long)) 199 200 static int parse_probe_vars(char *arg, const struct fetch_type *t, 201 struct fetch_insn *code, unsigned int flags) 202 { 203 unsigned long param; 204 int ret = 0; 205 int len; 206 207 if (strcmp(arg, "retval") == 0) { 208 if (flags & TPARG_FL_RETURN) 209 code->op = FETCH_OP_RETVAL; 210 else 211 ret = -EINVAL; 212 } else if ((len = str_has_prefix(arg, "stack"))) { 213 if (arg[len] == '\0') { 214 code->op = FETCH_OP_STACKP; 215 } else if (isdigit(arg[len])) { 216 ret = kstrtoul(arg + len, 10, ¶m); 217 if (ret || ((flags & TPARG_FL_KERNEL) && 218 param > PARAM_MAX_STACK)) 219 ret = -EINVAL; 220 else { 221 code->op = FETCH_OP_STACK; 222 code->param = (unsigned int)param; 223 } 224 } else 225 ret = -EINVAL; 226 } else if (strcmp(arg, "comm") == 0) { 227 code->op = FETCH_OP_COMM; 228 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API 229 } else if (((flags & TPARG_FL_MASK) == 230 (TPARG_FL_KERNEL | TPARG_FL_FENTRY)) && 231 (len = str_has_prefix(arg, "arg"))) { 232 if (!isdigit(arg[len])) 233 return -EINVAL; 234 ret = kstrtoul(arg + len, 10, ¶m); 235 if (ret || !param || param > PARAM_MAX_STACK) 236 return -EINVAL; 237 code->op = FETCH_OP_ARG; 238 code->param = (unsigned int)param - 1; 239 #endif 240 } else 241 ret = -EINVAL; 242 243 return ret; 244 } 245 246 /* Recursive argument parser */ 247 static int 248 parse_probe_arg(char *arg, const struct fetch_type *type, 249 struct fetch_insn **pcode, struct fetch_insn *end, 250 unsigned int flags) 251 { 252 struct fetch_insn *code = *pcode; 253 unsigned long param; 254 long offset = 0; 255 char *tmp; 256 int ret = 0; 257 258 switch (arg[0]) { 259 case '$': 260 ret = parse_probe_vars(arg + 1, type, code, flags); 261 break; 262 263 case '%': /* named register */ 264 ret = regs_query_register_offset(arg + 1); 265 if (ret >= 0) { 266 code->op = FETCH_OP_REG; 267 code->param = (unsigned int)ret; 268 ret = 0; 269 } 270 break; 271 272 case '@': /* memory, file-offset or symbol */ 273 if (isdigit(arg[1])) { 274 ret = kstrtoul(arg + 1, 0, ¶m); 275 if (ret) 276 break; 277 /* load address */ 278 code->op = FETCH_OP_IMM; 279 code->immediate = param; 280 } else if (arg[1] == '+') { 281 /* kprobes don't support file offsets */ 282 if (flags & TPARG_FL_KERNEL) 283 return -EINVAL; 284 285 ret = kstrtol(arg + 2, 0, &offset); 286 if (ret) 287 break; 288 289 code->op = FETCH_OP_FOFFS; 290 code->immediate = (unsigned long)offset; // imm64? 291 } else { 292 /* uprobes don't support symbols */ 293 if (!(flags & TPARG_FL_KERNEL)) 294 return -EINVAL; 295 296 /* Preserve symbol for updating */ 297 code->op = FETCH_NOP_SYMBOL; 298 code->data = kstrdup(arg + 1, GFP_KERNEL); 299 if (!code->data) 300 return -ENOMEM; 301 if (++code == end) 302 return -E2BIG; 303 304 code->op = FETCH_OP_IMM; 305 code->immediate = 0; 306 } 307 /* These are fetching from memory */ 308 if (++code == end) 309 return -E2BIG; 310 *pcode = code; 311 code->op = FETCH_OP_DEREF; 312 code->offset = offset; 313 break; 314 315 case '+': /* deref memory */ 316 arg++; /* Skip '+', because kstrtol() rejects it. */ 317 /* fall through */ 318 case '-': 319 tmp = strchr(arg, '('); 320 if (!tmp) 321 return -EINVAL; 322 323 *tmp = '\0'; 324 ret = kstrtol(arg, 0, &offset); 325 if (ret) 326 break; 327 328 arg = tmp + 1; 329 tmp = strrchr(arg, ')'); 330 331 if (tmp) { 332 const struct fetch_type *t2 = find_fetch_type(NULL); 333 334 *tmp = '\0'; 335 ret = parse_probe_arg(arg, t2, &code, end, flags); 336 if (ret) 337 break; 338 if (code->op == FETCH_OP_COMM) 339 return -EINVAL; 340 if (++code == end) 341 return -E2BIG; 342 *pcode = code; 343 344 code->op = FETCH_OP_DEREF; 345 code->offset = offset; 346 } 347 break; 348 } 349 if (!ret && code->op == FETCH_OP_NOP) { 350 /* Parsed, but do not find fetch method */ 351 ret = -EINVAL; 352 } 353 return ret; 354 } 355 356 #define BYTES_TO_BITS(nb) ((BITS_PER_LONG * (nb)) / sizeof(long)) 357 358 /* Bitfield type needs to be parsed into a fetch function */ 359 static int __parse_bitfield_probe_arg(const char *bf, 360 const struct fetch_type *t, 361 struct fetch_insn **pcode) 362 { 363 struct fetch_insn *code = *pcode; 364 unsigned long bw, bo; 365 char *tail; 366 367 if (*bf != 'b') 368 return 0; 369 370 bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */ 371 372 if (bw == 0 || *tail != '@') 373 return -EINVAL; 374 375 bf = tail + 1; 376 bo = simple_strtoul(bf, &tail, 0); 377 378 if (tail == bf || *tail != '/') 379 return -EINVAL; 380 code++; 381 if (code->op != FETCH_OP_NOP) 382 return -E2BIG; 383 *pcode = code; 384 385 code->op = FETCH_OP_MOD_BF; 386 code->lshift = BYTES_TO_BITS(t->size) - (bw + bo); 387 code->rshift = BYTES_TO_BITS(t->size) - bw; 388 code->basesize = t->size; 389 390 return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0; 391 } 392 393 /* String length checking wrapper */ 394 static int traceprobe_parse_probe_arg_body(char *arg, ssize_t *size, 395 struct probe_arg *parg, unsigned int flags) 396 { 397 struct fetch_insn *code, *scode, *tmp = NULL; 398 char *t, *t2; 399 int ret, len; 400 401 if (strlen(arg) > MAX_ARGSTR_LEN) { 402 pr_info("Argument is too long.: %s\n", arg); 403 return -ENOSPC; 404 } 405 parg->comm = kstrdup(arg, GFP_KERNEL); 406 if (!parg->comm) { 407 pr_info("Failed to allocate memory for command '%s'.\n", arg); 408 return -ENOMEM; 409 } 410 t = strchr(arg, ':'); 411 if (t) { 412 *t = '\0'; 413 t2 = strchr(++t, '['); 414 if (t2) { 415 *t2 = '\0'; 416 parg->count = simple_strtoul(t2 + 1, &t2, 0); 417 if (strcmp(t2, "]") || parg->count == 0) 418 return -EINVAL; 419 if (parg->count > MAX_ARRAY_LEN) 420 return -E2BIG; 421 } 422 } 423 /* 424 * The default type of $comm should be "string", and it can't be 425 * dereferenced. 426 */ 427 if (!t && strcmp(arg, "$comm") == 0) 428 parg->type = find_fetch_type("string"); 429 else 430 parg->type = find_fetch_type(t); 431 if (!parg->type) { 432 pr_info("Unsupported type: %s\n", t); 433 return -EINVAL; 434 } 435 parg->offset = *size; 436 *size += parg->type->size * (parg->count ?: 1); 437 438 if (parg->count) { 439 len = strlen(parg->type->fmttype) + 6; 440 parg->fmt = kmalloc(len, GFP_KERNEL); 441 if (!parg->fmt) 442 return -ENOMEM; 443 snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype, 444 parg->count); 445 } 446 447 code = tmp = kzalloc(sizeof(*code) * FETCH_INSN_MAX, GFP_KERNEL); 448 if (!code) 449 return -ENOMEM; 450 code[FETCH_INSN_MAX - 1].op = FETCH_OP_END; 451 452 ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1], 453 flags); 454 if (ret) 455 goto fail; 456 457 /* Store operation */ 458 if (!strcmp(parg->type->name, "string")) { 459 if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_IMM && 460 code->op != FETCH_OP_COMM) { 461 pr_info("string only accepts memory or address.\n"); 462 ret = -EINVAL; 463 goto fail; 464 } 465 if (code->op != FETCH_OP_DEREF || parg->count) { 466 /* 467 * IMM and COMM is pointing actual address, those must 468 * be kept, and if parg->count != 0, this is an array 469 * of string pointers instead of string address itself. 470 */ 471 code++; 472 if (code->op != FETCH_OP_NOP) { 473 ret = -E2BIG; 474 goto fail; 475 } 476 } 477 code->op = FETCH_OP_ST_STRING; /* In DEREF case, replace it */ 478 code->size = parg->type->size; 479 parg->dynamic = true; 480 } else if (code->op == FETCH_OP_DEREF) { 481 code->op = FETCH_OP_ST_MEM; 482 code->size = parg->type->size; 483 } else { 484 code++; 485 if (code->op != FETCH_OP_NOP) { 486 ret = -E2BIG; 487 goto fail; 488 } 489 code->op = FETCH_OP_ST_RAW; 490 code->size = parg->type->size; 491 } 492 scode = code; 493 /* Modify operation */ 494 if (t != NULL) { 495 ret = __parse_bitfield_probe_arg(t, parg->type, &code); 496 if (ret) 497 goto fail; 498 } 499 /* Loop(Array) operation */ 500 if (parg->count) { 501 if (scode->op != FETCH_OP_ST_MEM && 502 scode->op != FETCH_OP_ST_STRING) { 503 pr_info("array only accepts memory or address\n"); 504 ret = -EINVAL; 505 goto fail; 506 } 507 code++; 508 if (code->op != FETCH_OP_NOP) { 509 ret = -E2BIG; 510 goto fail; 511 } 512 code->op = FETCH_OP_LP_ARRAY; 513 code->param = parg->count; 514 } 515 code++; 516 code->op = FETCH_OP_END; 517 518 /* Shrink down the code buffer */ 519 parg->code = kzalloc(sizeof(*code) * (code - tmp + 1), GFP_KERNEL); 520 if (!parg->code) 521 ret = -ENOMEM; 522 else 523 memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1)); 524 525 fail: 526 if (ret) { 527 for (code = tmp; code < tmp + FETCH_INSN_MAX; code++) 528 if (code->op == FETCH_NOP_SYMBOL) 529 kfree(code->data); 530 } 531 kfree(tmp); 532 533 return ret; 534 } 535 536 /* Return 1 if name is reserved or already used by another argument */ 537 static int traceprobe_conflict_field_name(const char *name, 538 struct probe_arg *args, int narg) 539 { 540 int i; 541 542 for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++) 543 if (strcmp(reserved_field_names[i], name) == 0) 544 return 1; 545 546 for (i = 0; i < narg; i++) 547 if (strcmp(args[i].name, name) == 0) 548 return 1; 549 550 return 0; 551 } 552 553 int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, char *arg, 554 unsigned int flags) 555 { 556 struct probe_arg *parg = &tp->args[i]; 557 char *body; 558 int ret; 559 560 /* Increment count for freeing args in error case */ 561 tp->nr_args++; 562 563 body = strchr(arg, '='); 564 if (body) { 565 if (body - arg > MAX_ARG_NAME_LEN || body == arg) 566 return -EINVAL; 567 parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL); 568 body++; 569 } else { 570 /* If argument name is omitted, set "argN" */ 571 parg->name = kasprintf(GFP_KERNEL, "arg%d", i + 1); 572 body = arg; 573 } 574 if (!parg->name) 575 return -ENOMEM; 576 577 if (!is_good_name(parg->name)) { 578 pr_info("Invalid argument[%d] name: %s\n", 579 i, parg->name); 580 return -EINVAL; 581 } 582 583 if (traceprobe_conflict_field_name(parg->name, tp->args, i)) { 584 pr_info("Argument[%d]: '%s' conflicts with another field.\n", 585 i, parg->name); 586 return -EINVAL; 587 } 588 589 /* Parse fetch argument */ 590 ret = traceprobe_parse_probe_arg_body(body, &tp->size, parg, flags); 591 if (ret) 592 pr_info("Parse error at argument[%d]. (%d)\n", i, ret); 593 return ret; 594 } 595 596 void traceprobe_free_probe_arg(struct probe_arg *arg) 597 { 598 struct fetch_insn *code = arg->code; 599 600 while (code && code->op != FETCH_OP_END) { 601 if (code->op == FETCH_NOP_SYMBOL) 602 kfree(code->data); 603 code++; 604 } 605 kfree(arg->code); 606 kfree(arg->name); 607 kfree(arg->comm); 608 kfree(arg->fmt); 609 } 610 611 int traceprobe_update_arg(struct probe_arg *arg) 612 { 613 struct fetch_insn *code = arg->code; 614 long offset; 615 char *tmp; 616 char c; 617 int ret = 0; 618 619 while (code && code->op != FETCH_OP_END) { 620 if (code->op == FETCH_NOP_SYMBOL) { 621 if (code[1].op != FETCH_OP_IMM) 622 return -EINVAL; 623 624 tmp = strpbrk(code->data, "+-"); 625 if (tmp) 626 c = *tmp; 627 ret = traceprobe_split_symbol_offset(code->data, 628 &offset); 629 if (ret) 630 return ret; 631 632 code[1].immediate = 633 (unsigned long)kallsyms_lookup_name(code->data); 634 if (tmp) 635 *tmp = c; 636 if (!code[1].immediate) 637 return -ENOENT; 638 code[1].immediate += offset; 639 } 640 code++; 641 } 642 return 0; 643 } 644 645 /* When len=0, we just calculate the needed length */ 646 #define LEN_OR_ZERO (len ? len - pos : 0) 647 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len, 648 bool is_return) 649 { 650 struct probe_arg *parg; 651 int i, j; 652 int pos = 0; 653 const char *fmt, *arg; 654 655 if (!is_return) { 656 fmt = "(%lx)"; 657 arg = "REC->" FIELD_STRING_IP; 658 } else { 659 fmt = "(%lx <- %lx)"; 660 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP; 661 } 662 663 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt); 664 665 for (i = 0; i < tp->nr_args; i++) { 666 parg = tp->args + i; 667 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name); 668 if (parg->count) { 669 pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s", 670 parg->type->fmt); 671 for (j = 1; j < parg->count; j++) 672 pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s", 673 parg->type->fmt); 674 pos += snprintf(buf + pos, LEN_OR_ZERO, "}"); 675 } else 676 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s", 677 parg->type->fmt); 678 } 679 680 pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg); 681 682 for (i = 0; i < tp->nr_args; i++) { 683 parg = tp->args + i; 684 if (parg->count) { 685 if (strcmp(parg->type->name, "string") == 0) 686 fmt = ", __get_str(%s[%d])"; 687 else 688 fmt = ", REC->%s[%d]"; 689 for (j = 0; j < parg->count; j++) 690 pos += snprintf(buf + pos, LEN_OR_ZERO, 691 fmt, parg->name, j); 692 } else { 693 if (strcmp(parg->type->name, "string") == 0) 694 fmt = ", __get_str(%s)"; 695 else 696 fmt = ", REC->%s"; 697 pos += snprintf(buf + pos, LEN_OR_ZERO, 698 fmt, parg->name); 699 } 700 } 701 702 /* return the length of print_fmt */ 703 return pos; 704 } 705 #undef LEN_OR_ZERO 706 707 int traceprobe_set_print_fmt(struct trace_probe *tp, bool is_return) 708 { 709 int len; 710 char *print_fmt; 711 712 /* First: called with 0 length to calculate the needed length */ 713 len = __set_print_fmt(tp, NULL, 0, is_return); 714 print_fmt = kmalloc(len + 1, GFP_KERNEL); 715 if (!print_fmt) 716 return -ENOMEM; 717 718 /* Second: actually write the @print_fmt */ 719 __set_print_fmt(tp, print_fmt, len + 1, is_return); 720 tp->call.print_fmt = print_fmt; 721 722 return 0; 723 } 724 725 int traceprobe_define_arg_fields(struct trace_event_call *event_call, 726 size_t offset, struct trace_probe *tp) 727 { 728 int ret, i; 729 730 /* Set argument names as fields */ 731 for (i = 0; i < tp->nr_args; i++) { 732 struct probe_arg *parg = &tp->args[i]; 733 const char *fmt = parg->type->fmttype; 734 int size = parg->type->size; 735 736 if (parg->fmt) 737 fmt = parg->fmt; 738 if (parg->count) 739 size *= parg->count; 740 ret = trace_define_field(event_call, fmt, parg->name, 741 offset + parg->offset, size, 742 parg->type->is_signed, 743 FILTER_OTHER); 744 if (ret) 745 return ret; 746 } 747 return 0; 748 } 749