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 <linux/bpf.h> 15 #include "trace_btf.h" 16 17 #include "trace_probe.h" 18 19 #undef C 20 #define C(a, b) b 21 22 static const char *trace_probe_err_text[] = { ERRORS }; 23 24 static const char *reserved_field_names[] = { 25 "common_type", 26 "common_flags", 27 "common_preempt_count", 28 "common_pid", 29 "common_tgid", 30 FIELD_STRING_IP, 31 FIELD_STRING_RETIP, 32 FIELD_STRING_FUNC, 33 }; 34 35 /* Printing in basic type function template */ 36 #define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt) \ 37 int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\ 38 { \ 39 trace_seq_printf(s, fmt, *(type *)data); \ 40 return !trace_seq_has_overflowed(s); \ 41 } \ 42 const char PRINT_TYPE_FMT_NAME(tname)[] = fmt; 43 44 DEFINE_BASIC_PRINT_TYPE_FUNC(u8, u8, "%u") 45 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u") 46 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u") 47 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu") 48 DEFINE_BASIC_PRINT_TYPE_FUNC(s8, s8, "%d") 49 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d") 50 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d") 51 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld") 52 DEFINE_BASIC_PRINT_TYPE_FUNC(x8, u8, "0x%x") 53 DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x") 54 DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x") 55 DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx") 56 DEFINE_BASIC_PRINT_TYPE_FUNC(char, u8, "'%c'") 57 58 int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent) 59 { 60 trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data); 61 return !trace_seq_has_overflowed(s); 62 } 63 const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS"; 64 65 /* Print type function for string type */ 66 int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent) 67 { 68 int len = *(u32 *)data >> 16; 69 70 if (!len) 71 trace_seq_puts(s, FAULT_STRING); 72 else 73 trace_seq_printf(s, "\"%s\"", 74 (const char *)get_loc_data(data, ent)); 75 return !trace_seq_has_overflowed(s); 76 } 77 78 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\""; 79 80 /* Fetch type information table */ 81 static const struct fetch_type probe_fetch_types[] = { 82 /* Special types */ 83 __ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1, 1, 84 "__data_loc char[]"), 85 __ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1, 1, 86 "__data_loc char[]"), 87 __ASSIGN_FETCH_TYPE("symstr", string, string, sizeof(u32), 1, 1, 88 "__data_loc char[]"), 89 /* Basic types */ 90 ASSIGN_FETCH_TYPE(u8, u8, 0), 91 ASSIGN_FETCH_TYPE(u16, u16, 0), 92 ASSIGN_FETCH_TYPE(u32, u32, 0), 93 ASSIGN_FETCH_TYPE(u64, u64, 0), 94 ASSIGN_FETCH_TYPE(s8, u8, 1), 95 ASSIGN_FETCH_TYPE(s16, u16, 1), 96 ASSIGN_FETCH_TYPE(s32, u32, 1), 97 ASSIGN_FETCH_TYPE(s64, u64, 1), 98 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0), 99 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0), 100 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0), 101 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0), 102 ASSIGN_FETCH_TYPE_ALIAS(char, u8, u8, 0), 103 ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0), 104 105 ASSIGN_FETCH_TYPE_END 106 }; 107 108 static const struct fetch_type *find_fetch_type(const char *type, unsigned long flags) 109 { 110 int i; 111 112 /* Reject the symbol/symstr for uprobes */ 113 if (type && (flags & TPARG_FL_USER) && 114 (!strcmp(type, "symbol") || !strcmp(type, "symstr"))) 115 return NULL; 116 117 if (!type) 118 type = DEFAULT_FETCH_TYPE_STR; 119 120 /* Special case: bitfield */ 121 if (*type == 'b') { 122 unsigned long bs; 123 124 type = strchr(type, '/'); 125 if (!type) 126 goto fail; 127 128 type++; 129 if (kstrtoul(type, 0, &bs)) 130 goto fail; 131 132 switch (bs) { 133 case 8: 134 return find_fetch_type("u8", flags); 135 case 16: 136 return find_fetch_type("u16", flags); 137 case 32: 138 return find_fetch_type("u32", flags); 139 case 64: 140 return find_fetch_type("u64", flags); 141 default: 142 goto fail; 143 } 144 } 145 146 for (i = 0; probe_fetch_types[i].name; i++) { 147 if (strcmp(type, probe_fetch_types[i].name) == 0) 148 return &probe_fetch_types[i]; 149 } 150 151 fail: 152 return NULL; 153 } 154 155 static struct trace_probe_log trace_probe_log; 156 157 void trace_probe_log_init(const char *subsystem, int argc, const char **argv) 158 { 159 trace_probe_log.subsystem = subsystem; 160 trace_probe_log.argc = argc; 161 trace_probe_log.argv = argv; 162 trace_probe_log.index = 0; 163 } 164 165 void trace_probe_log_clear(void) 166 { 167 memset(&trace_probe_log, 0, sizeof(trace_probe_log)); 168 } 169 170 void trace_probe_log_set_index(int index) 171 { 172 trace_probe_log.index = index; 173 } 174 175 void __trace_probe_log_err(int offset, int err_type) 176 { 177 char *command, *p; 178 int i, len = 0, pos = 0; 179 180 if (!trace_probe_log.argv) 181 return; 182 183 /* Recalculate the length and allocate buffer */ 184 for (i = 0; i < trace_probe_log.argc; i++) { 185 if (i == trace_probe_log.index) 186 pos = len; 187 len += strlen(trace_probe_log.argv[i]) + 1; 188 } 189 command = kzalloc(len, GFP_KERNEL); 190 if (!command) 191 return; 192 193 if (trace_probe_log.index >= trace_probe_log.argc) { 194 /** 195 * Set the error position is next to the last arg + space. 196 * Note that len includes the terminal null and the cursor 197 * appears at pos + 1. 198 */ 199 pos = len; 200 offset = 0; 201 } 202 203 /* And make a command string from argv array */ 204 p = command; 205 for (i = 0; i < trace_probe_log.argc; i++) { 206 len = strlen(trace_probe_log.argv[i]); 207 strcpy(p, trace_probe_log.argv[i]); 208 p[len] = ' '; 209 p += len + 1; 210 } 211 *(p - 1) = '\0'; 212 213 tracing_log_err(NULL, trace_probe_log.subsystem, command, 214 trace_probe_err_text, err_type, pos + offset); 215 216 kfree(command); 217 } 218 219 /* Split symbol and offset. */ 220 int traceprobe_split_symbol_offset(char *symbol, long *offset) 221 { 222 char *tmp; 223 int ret; 224 225 if (!offset) 226 return -EINVAL; 227 228 tmp = strpbrk(symbol, "+-"); 229 if (tmp) { 230 ret = kstrtol(tmp, 0, offset); 231 if (ret) 232 return ret; 233 *tmp = '\0'; 234 } else 235 *offset = 0; 236 237 return 0; 238 } 239 240 /* @buf must has MAX_EVENT_NAME_LEN size */ 241 int traceprobe_parse_event_name(const char **pevent, const char **pgroup, 242 char *buf, int offset) 243 { 244 const char *slash, *event = *pevent; 245 int len; 246 247 slash = strchr(event, '/'); 248 if (!slash) 249 slash = strchr(event, '.'); 250 251 if (slash) { 252 if (slash == event) { 253 trace_probe_log_err(offset, NO_GROUP_NAME); 254 return -EINVAL; 255 } 256 if (slash - event + 1 > MAX_EVENT_NAME_LEN) { 257 trace_probe_log_err(offset, GROUP_TOO_LONG); 258 return -EINVAL; 259 } 260 strscpy(buf, event, slash - event + 1); 261 if (!is_good_system_name(buf)) { 262 trace_probe_log_err(offset, BAD_GROUP_NAME); 263 return -EINVAL; 264 } 265 *pgroup = buf; 266 *pevent = slash + 1; 267 offset += slash - event + 1; 268 event = *pevent; 269 } 270 len = strlen(event); 271 if (len == 0) { 272 if (slash) { 273 *pevent = NULL; 274 return 0; 275 } 276 trace_probe_log_err(offset, NO_EVENT_NAME); 277 return -EINVAL; 278 } else if (len > MAX_EVENT_NAME_LEN) { 279 trace_probe_log_err(offset, EVENT_TOO_LONG); 280 return -EINVAL; 281 } 282 if (!is_good_name(event)) { 283 trace_probe_log_err(offset, BAD_EVENT_NAME); 284 return -EINVAL; 285 } 286 return 0; 287 } 288 289 static int parse_trace_event_arg(char *arg, struct fetch_insn *code, 290 struct traceprobe_parse_context *ctx) 291 { 292 struct ftrace_event_field *field; 293 struct list_head *head; 294 295 head = trace_get_fields(ctx->event); 296 list_for_each_entry(field, head, link) { 297 if (!strcmp(arg, field->name)) { 298 code->op = FETCH_OP_TP_ARG; 299 code->data = field; 300 return 0; 301 } 302 } 303 return -ENOENT; 304 } 305 306 #ifdef CONFIG_PROBE_EVENTS_BTF_ARGS 307 308 static u32 btf_type_int(const struct btf_type *t) 309 { 310 return *(u32 *)(t + 1); 311 } 312 313 static bool btf_type_is_char_ptr(struct btf *btf, const struct btf_type *type) 314 { 315 const struct btf_type *real_type; 316 u32 intdata; 317 s32 tid; 318 319 real_type = btf_type_skip_modifiers(btf, type->type, &tid); 320 if (!real_type) 321 return false; 322 323 if (BTF_INFO_KIND(real_type->info) != BTF_KIND_INT) 324 return false; 325 326 intdata = btf_type_int(real_type); 327 return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED) 328 && BTF_INT_BITS(intdata) == 8; 329 } 330 331 static bool btf_type_is_char_array(struct btf *btf, const struct btf_type *type) 332 { 333 const struct btf_type *real_type; 334 const struct btf_array *array; 335 u32 intdata; 336 s32 tid; 337 338 if (BTF_INFO_KIND(type->info) != BTF_KIND_ARRAY) 339 return false; 340 341 array = (const struct btf_array *)(type + 1); 342 343 real_type = btf_type_skip_modifiers(btf, array->type, &tid); 344 345 intdata = btf_type_int(real_type); 346 return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED) 347 && BTF_INT_BITS(intdata) == 8; 348 } 349 350 static int check_prepare_btf_string_fetch(char *typename, 351 struct fetch_insn **pcode, 352 struct traceprobe_parse_context *ctx) 353 { 354 struct btf *btf = ctx->btf; 355 356 if (!btf || !ctx->last_type) 357 return 0; 358 359 /* char [] does not need any change. */ 360 if (btf_type_is_char_array(btf, ctx->last_type)) 361 return 0; 362 363 /* char * requires dereference the pointer. */ 364 if (btf_type_is_char_ptr(btf, ctx->last_type)) { 365 struct fetch_insn *code = *pcode + 1; 366 367 if (code->op == FETCH_OP_END) { 368 trace_probe_log_err(ctx->offset, TOO_MANY_OPS); 369 return -E2BIG; 370 } 371 if (typename[0] == 'u') 372 code->op = FETCH_OP_UDEREF; 373 else 374 code->op = FETCH_OP_DEREF; 375 code->offset = 0; 376 *pcode = code; 377 return 0; 378 } 379 /* Other types are not available for string */ 380 trace_probe_log_err(ctx->offset, BAD_TYPE4STR); 381 return -EINVAL; 382 } 383 384 static const char *fetch_type_from_btf_type(struct btf *btf, 385 const struct btf_type *type, 386 struct traceprobe_parse_context *ctx) 387 { 388 u32 intdata; 389 390 /* TODO: const char * could be converted as a string */ 391 switch (BTF_INFO_KIND(type->info)) { 392 case BTF_KIND_ENUM: 393 /* enum is "int", so convert to "s32" */ 394 return "s32"; 395 case BTF_KIND_ENUM64: 396 return "s64"; 397 case BTF_KIND_PTR: 398 /* pointer will be converted to "x??" */ 399 if (IS_ENABLED(CONFIG_64BIT)) 400 return "x64"; 401 else 402 return "x32"; 403 case BTF_KIND_INT: 404 intdata = btf_type_int(type); 405 if (BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED) { 406 switch (BTF_INT_BITS(intdata)) { 407 case 8: 408 return "s8"; 409 case 16: 410 return "s16"; 411 case 32: 412 return "s32"; 413 case 64: 414 return "s64"; 415 } 416 } else { /* unsigned */ 417 switch (BTF_INT_BITS(intdata)) { 418 case 8: 419 return "u8"; 420 case 16: 421 return "u16"; 422 case 32: 423 return "u32"; 424 case 64: 425 return "u64"; 426 } 427 /* bitfield, size is encoded in the type */ 428 ctx->last_bitsize = BTF_INT_BITS(intdata); 429 ctx->last_bitoffs += BTF_INT_OFFSET(intdata); 430 return "u64"; 431 } 432 } 433 /* TODO: support other types */ 434 435 return NULL; 436 } 437 438 static int query_btf_context(struct traceprobe_parse_context *ctx) 439 { 440 const struct btf_param *param; 441 const struct btf_type *type; 442 struct btf *btf; 443 s32 nr; 444 445 if (ctx->btf) 446 return 0; 447 448 if (!ctx->funcname) 449 return -EINVAL; 450 451 type = btf_find_func_proto(ctx->funcname, &btf); 452 if (!type) 453 return -ENOENT; 454 455 ctx->btf = btf; 456 ctx->proto = type; 457 458 /* ctx->params is optional, since func(void) will not have params. */ 459 nr = 0; 460 param = btf_get_func_param(type, &nr); 461 if (!IS_ERR_OR_NULL(param)) { 462 /* Hide the first 'data' argument of tracepoint */ 463 if (ctx->flags & TPARG_FL_TPOINT) { 464 nr--; 465 param++; 466 } 467 } 468 469 if (nr > 0) { 470 ctx->nr_params = nr; 471 ctx->params = param; 472 } else { 473 ctx->nr_params = 0; 474 ctx->params = NULL; 475 } 476 477 return 0; 478 } 479 480 static void clear_btf_context(struct traceprobe_parse_context *ctx) 481 { 482 if (ctx->btf) { 483 btf_put(ctx->btf); 484 ctx->btf = NULL; 485 ctx->proto = NULL; 486 ctx->params = NULL; 487 ctx->nr_params = 0; 488 } 489 } 490 491 /* Return 1 if the field separater is arrow operator ('->') */ 492 static int split_next_field(char *varname, char **next_field, 493 struct traceprobe_parse_context *ctx) 494 { 495 char *field; 496 int ret = 0; 497 498 field = strpbrk(varname, ".-"); 499 if (field) { 500 if (field[0] == '-' && field[1] == '>') { 501 field[0] = '\0'; 502 field += 2; 503 ret = 1; 504 } else if (field[0] == '.') { 505 field[0] = '\0'; 506 field += 1; 507 } else { 508 trace_probe_log_err(ctx->offset + field - varname, BAD_HYPHEN); 509 return -EINVAL; 510 } 511 *next_field = field; 512 } 513 514 return ret; 515 } 516 517 /* 518 * Parse the field of data structure. The @type must be a pointer type 519 * pointing the target data structure type. 520 */ 521 static int parse_btf_field(char *fieldname, const struct btf_type *type, 522 struct fetch_insn **pcode, struct fetch_insn *end, 523 struct traceprobe_parse_context *ctx) 524 { 525 struct fetch_insn *code = *pcode; 526 const struct btf_member *field; 527 u32 bitoffs, anon_offs; 528 char *next; 529 int is_ptr; 530 s32 tid; 531 532 do { 533 /* Outer loop for solving arrow operator ('->') */ 534 if (BTF_INFO_KIND(type->info) != BTF_KIND_PTR) { 535 trace_probe_log_err(ctx->offset, NO_PTR_STRCT); 536 return -EINVAL; 537 } 538 /* Convert a struct pointer type to a struct type */ 539 type = btf_type_skip_modifiers(ctx->btf, type->type, &tid); 540 if (!type) { 541 trace_probe_log_err(ctx->offset, BAD_BTF_TID); 542 return -EINVAL; 543 } 544 545 bitoffs = 0; 546 do { 547 /* Inner loop for solving dot operator ('.') */ 548 next = NULL; 549 is_ptr = split_next_field(fieldname, &next, ctx); 550 if (is_ptr < 0) 551 return is_ptr; 552 553 anon_offs = 0; 554 field = btf_find_struct_member(ctx->btf, type, fieldname, 555 &anon_offs); 556 if (!field) { 557 trace_probe_log_err(ctx->offset, NO_BTF_FIELD); 558 return -ENOENT; 559 } 560 /* Add anonymous structure/union offset */ 561 bitoffs += anon_offs; 562 563 /* Accumulate the bit-offsets of the dot-connected fields */ 564 if (btf_type_kflag(type)) { 565 bitoffs += BTF_MEMBER_BIT_OFFSET(field->offset); 566 ctx->last_bitsize = BTF_MEMBER_BITFIELD_SIZE(field->offset); 567 } else { 568 bitoffs += field->offset; 569 ctx->last_bitsize = 0; 570 } 571 572 type = btf_type_skip_modifiers(ctx->btf, field->type, &tid); 573 if (!type) { 574 trace_probe_log_err(ctx->offset, BAD_BTF_TID); 575 return -EINVAL; 576 } 577 578 ctx->offset += next - fieldname; 579 fieldname = next; 580 } while (!is_ptr && fieldname); 581 582 if (++code == end) { 583 trace_probe_log_err(ctx->offset, TOO_MANY_OPS); 584 return -EINVAL; 585 } 586 code->op = FETCH_OP_DEREF; /* TODO: user deref support */ 587 code->offset = bitoffs / 8; 588 *pcode = code; 589 590 ctx->last_bitoffs = bitoffs % 8; 591 ctx->last_type = type; 592 } while (fieldname); 593 594 return 0; 595 } 596 597 static int __store_entry_arg(struct trace_probe *tp, int argnum); 598 599 static int parse_btf_arg(char *varname, 600 struct fetch_insn **pcode, struct fetch_insn *end, 601 struct traceprobe_parse_context *ctx) 602 { 603 struct fetch_insn *code = *pcode; 604 const struct btf_param *params; 605 const struct btf_type *type; 606 char *field = NULL; 607 int i, is_ptr, ret; 608 u32 tid; 609 610 if (WARN_ON_ONCE(!ctx->funcname)) 611 return -EINVAL; 612 613 is_ptr = split_next_field(varname, &field, ctx); 614 if (is_ptr < 0) 615 return is_ptr; 616 if (!is_ptr && field) { 617 /* dot-connected field on an argument is not supported. */ 618 trace_probe_log_err(ctx->offset + field - varname, 619 NOSUP_DAT_ARG); 620 return -EOPNOTSUPP; 621 } 622 623 if (ctx->flags & TPARG_FL_RETURN && !strcmp(varname, "$retval")) { 624 code->op = FETCH_OP_RETVAL; 625 /* Check whether the function return type is not void */ 626 if (query_btf_context(ctx) == 0) { 627 if (ctx->proto->type == 0) { 628 trace_probe_log_err(ctx->offset, NO_RETVAL); 629 return -ENOENT; 630 } 631 tid = ctx->proto->type; 632 goto found; 633 } 634 if (field) { 635 trace_probe_log_err(ctx->offset + field - varname, 636 NO_BTF_ENTRY); 637 return -ENOENT; 638 } 639 return 0; 640 } 641 642 if (!ctx->btf) { 643 ret = query_btf_context(ctx); 644 if (ret < 0 || ctx->nr_params == 0) { 645 trace_probe_log_err(ctx->offset, NO_BTF_ENTRY); 646 return PTR_ERR(params); 647 } 648 } 649 params = ctx->params; 650 651 for (i = 0; i < ctx->nr_params; i++) { 652 const char *name = btf_name_by_offset(ctx->btf, params[i].name_off); 653 654 if (name && !strcmp(name, varname)) { 655 if (tparg_is_function_entry(ctx->flags)) { 656 code->op = FETCH_OP_ARG; 657 if (ctx->flags & TPARG_FL_TPOINT) 658 code->param = i + 1; 659 else 660 code->param = i; 661 } else if (tparg_is_function_return(ctx->flags)) { 662 code->op = FETCH_OP_EDATA; 663 ret = __store_entry_arg(ctx->tp, i); 664 if (ret < 0) { 665 /* internal error */ 666 return ret; 667 } 668 code->offset = ret; 669 } 670 tid = params[i].type; 671 goto found; 672 } 673 } 674 trace_probe_log_err(ctx->offset, NO_BTFARG); 675 return -ENOENT; 676 677 found: 678 type = btf_type_skip_modifiers(ctx->btf, tid, &tid); 679 if (!type) { 680 trace_probe_log_err(ctx->offset, BAD_BTF_TID); 681 return -EINVAL; 682 } 683 /* Initialize the last type information */ 684 ctx->last_type = type; 685 ctx->last_bitoffs = 0; 686 ctx->last_bitsize = 0; 687 if (field) { 688 ctx->offset += field - varname; 689 return parse_btf_field(field, type, pcode, end, ctx); 690 } 691 return 0; 692 } 693 694 static const struct fetch_type *find_fetch_type_from_btf_type( 695 struct traceprobe_parse_context *ctx) 696 { 697 struct btf *btf = ctx->btf; 698 const char *typestr = NULL; 699 700 if (btf && ctx->last_type) 701 typestr = fetch_type_from_btf_type(btf, ctx->last_type, ctx); 702 703 return find_fetch_type(typestr, ctx->flags); 704 } 705 706 static int parse_btf_bitfield(struct fetch_insn **pcode, 707 struct traceprobe_parse_context *ctx) 708 { 709 struct fetch_insn *code = *pcode; 710 711 if ((ctx->last_bitsize % 8 == 0) && ctx->last_bitoffs == 0) 712 return 0; 713 714 code++; 715 if (code->op != FETCH_OP_NOP) { 716 trace_probe_log_err(ctx->offset, TOO_MANY_OPS); 717 return -EINVAL; 718 } 719 *pcode = code; 720 721 code->op = FETCH_OP_MOD_BF; 722 code->lshift = 64 - (ctx->last_bitsize + ctx->last_bitoffs); 723 code->rshift = 64 - ctx->last_bitsize; 724 code->basesize = 64 / 8; 725 return 0; 726 } 727 728 #else 729 static void clear_btf_context(struct traceprobe_parse_context *ctx) 730 { 731 ctx->btf = NULL; 732 } 733 734 static int query_btf_context(struct traceprobe_parse_context *ctx) 735 { 736 return -EOPNOTSUPP; 737 } 738 739 static int parse_btf_arg(char *varname, 740 struct fetch_insn **pcode, struct fetch_insn *end, 741 struct traceprobe_parse_context *ctx) 742 { 743 trace_probe_log_err(ctx->offset, NOSUP_BTFARG); 744 return -EOPNOTSUPP; 745 } 746 747 static int parse_btf_bitfield(struct fetch_insn **pcode, 748 struct traceprobe_parse_context *ctx) 749 { 750 trace_probe_log_err(ctx->offset, NOSUP_BTFARG); 751 return -EOPNOTSUPP; 752 } 753 754 #define find_fetch_type_from_btf_type(ctx) \ 755 find_fetch_type(NULL, ctx->flags) 756 757 static int check_prepare_btf_string_fetch(char *typename, 758 struct fetch_insn **pcode, 759 struct traceprobe_parse_context *ctx) 760 { 761 return 0; 762 } 763 764 #endif 765 766 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API 767 768 static int __store_entry_arg(struct trace_probe *tp, int argnum) 769 { 770 struct probe_entry_arg *earg = tp->entry_arg; 771 bool match = false; 772 int i, offset; 773 774 if (!earg) { 775 earg = kzalloc(sizeof(*tp->entry_arg), GFP_KERNEL); 776 if (!earg) 777 return -ENOMEM; 778 earg->size = 2 * tp->nr_args + 1; 779 earg->code = kcalloc(earg->size, sizeof(struct fetch_insn), 780 GFP_KERNEL); 781 if (!earg->code) { 782 kfree(earg); 783 return -ENOMEM; 784 } 785 /* Fill the code buffer with 'end' to simplify it */ 786 for (i = 0; i < earg->size; i++) 787 earg->code[i].op = FETCH_OP_END; 788 tp->entry_arg = earg; 789 } 790 791 offset = 0; 792 for (i = 0; i < earg->size - 1; i++) { 793 switch (earg->code[i].op) { 794 case FETCH_OP_END: 795 earg->code[i].op = FETCH_OP_ARG; 796 earg->code[i].param = argnum; 797 earg->code[i + 1].op = FETCH_OP_ST_EDATA; 798 earg->code[i + 1].offset = offset; 799 return offset; 800 case FETCH_OP_ARG: 801 match = (earg->code[i].param == argnum); 802 break; 803 case FETCH_OP_ST_EDATA: 804 offset = earg->code[i].offset; 805 if (match) 806 return offset; 807 offset += sizeof(unsigned long); 808 break; 809 default: 810 break; 811 } 812 } 813 return -ENOSPC; 814 } 815 816 int traceprobe_get_entry_data_size(struct trace_probe *tp) 817 { 818 struct probe_entry_arg *earg = tp->entry_arg; 819 int i, size = 0; 820 821 if (!earg) 822 return 0; 823 824 for (i = 0; i < earg->size; i++) { 825 switch (earg->code[i].op) { 826 case FETCH_OP_END: 827 goto out; 828 case FETCH_OP_ST_EDATA: 829 size = earg->code[i].offset + sizeof(unsigned long); 830 break; 831 default: 832 break; 833 } 834 } 835 out: 836 return size; 837 } 838 839 void store_trace_entry_data(void *edata, struct trace_probe *tp, struct pt_regs *regs) 840 { 841 struct probe_entry_arg *earg = tp->entry_arg; 842 unsigned long val; 843 int i; 844 845 if (!earg) 846 return; 847 848 for (i = 0; i < earg->size; i++) { 849 struct fetch_insn *code = &earg->code[i]; 850 851 switch (code->op) { 852 case FETCH_OP_ARG: 853 val = regs_get_kernel_argument(regs, code->param); 854 break; 855 case FETCH_OP_ST_EDATA: 856 *(unsigned long *)((unsigned long)edata + code->offset) = val; 857 break; 858 case FETCH_OP_END: 859 goto end; 860 default: 861 break; 862 } 863 } 864 end: 865 return; 866 } 867 NOKPROBE_SYMBOL(store_trace_entry_data) 868 #endif 869 870 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long)) 871 872 /* Parse $vars. @orig_arg points '$', which syncs to @ctx->offset */ 873 static int parse_probe_vars(char *orig_arg, const struct fetch_type *t, 874 struct fetch_insn **pcode, 875 struct fetch_insn *end, 876 struct traceprobe_parse_context *ctx) 877 { 878 struct fetch_insn *code = *pcode; 879 int err = TP_ERR_BAD_VAR; 880 char *arg = orig_arg + 1; 881 unsigned long param; 882 int ret = 0; 883 int len; 884 885 if (ctx->flags & TPARG_FL_TEVENT) { 886 if (code->data) 887 return -EFAULT; 888 ret = parse_trace_event_arg(arg, code, ctx); 889 if (!ret) 890 return 0; 891 if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) { 892 code->op = FETCH_OP_COMM; 893 return 0; 894 } 895 /* backward compatibility */ 896 ctx->offset = 0; 897 goto inval; 898 } 899 900 if (str_has_prefix(arg, "retval")) { 901 if (!(ctx->flags & TPARG_FL_RETURN)) { 902 err = TP_ERR_RETVAL_ON_PROBE; 903 goto inval; 904 } 905 if (!(ctx->flags & TPARG_FL_KERNEL) || 906 !IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) { 907 code->op = FETCH_OP_RETVAL; 908 return 0; 909 } 910 return parse_btf_arg(orig_arg, pcode, end, ctx); 911 } 912 913 len = str_has_prefix(arg, "stack"); 914 if (len) { 915 916 if (arg[len] == '\0') { 917 code->op = FETCH_OP_STACKP; 918 return 0; 919 } 920 921 if (isdigit(arg[len])) { 922 ret = kstrtoul(arg + len, 10, ¶m); 923 if (ret) 924 goto inval; 925 926 if ((ctx->flags & TPARG_FL_KERNEL) && 927 param > PARAM_MAX_STACK) { 928 err = TP_ERR_BAD_STACK_NUM; 929 goto inval; 930 } 931 code->op = FETCH_OP_STACK; 932 code->param = (unsigned int)param; 933 return 0; 934 } 935 goto inval; 936 } 937 938 if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) { 939 code->op = FETCH_OP_COMM; 940 return 0; 941 } 942 943 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API 944 len = str_has_prefix(arg, "arg"); 945 if (len) { 946 ret = kstrtoul(arg + len, 10, ¶m); 947 if (ret) 948 goto inval; 949 950 if (!param || param > PARAM_MAX_STACK) { 951 err = TP_ERR_BAD_ARG_NUM; 952 goto inval; 953 } 954 param--; /* argN starts from 1, but internal arg[N] starts from 0 */ 955 956 if (tparg_is_function_entry(ctx->flags)) { 957 code->op = FETCH_OP_ARG; 958 code->param = (unsigned int)param; 959 /* 960 * The tracepoint probe will probe a stub function, and the 961 * first parameter of the stub is a dummy and should be ignored. 962 */ 963 if (ctx->flags & TPARG_FL_TPOINT) 964 code->param++; 965 } else if (tparg_is_function_return(ctx->flags)) { 966 /* function entry argument access from return probe */ 967 ret = __store_entry_arg(ctx->tp, param); 968 if (ret < 0) /* This error should be an internal error */ 969 return ret; 970 971 code->op = FETCH_OP_EDATA; 972 code->offset = ret; 973 } else { 974 err = TP_ERR_NOFENTRY_ARGS; 975 goto inval; 976 } 977 return 0; 978 } 979 #endif 980 981 inval: 982 __trace_probe_log_err(ctx->offset, err); 983 return -EINVAL; 984 } 985 986 static int str_to_immediate(char *str, unsigned long *imm) 987 { 988 if (isdigit(str[0])) 989 return kstrtoul(str, 0, imm); 990 else if (str[0] == '-') 991 return kstrtol(str, 0, (long *)imm); 992 else if (str[0] == '+') 993 return kstrtol(str + 1, 0, (long *)imm); 994 return -EINVAL; 995 } 996 997 static int __parse_imm_string(char *str, char **pbuf, int offs) 998 { 999 size_t len = strlen(str); 1000 1001 if (str[len - 1] != '"') { 1002 trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE); 1003 return -EINVAL; 1004 } 1005 *pbuf = kstrndup(str, len - 1, GFP_KERNEL); 1006 if (!*pbuf) 1007 return -ENOMEM; 1008 return 0; 1009 } 1010 1011 /* Recursive argument parser */ 1012 static int 1013 parse_probe_arg(char *arg, const struct fetch_type *type, 1014 struct fetch_insn **pcode, struct fetch_insn *end, 1015 struct traceprobe_parse_context *ctx) 1016 { 1017 struct fetch_insn *code = *pcode; 1018 unsigned long param; 1019 int deref = FETCH_OP_DEREF; 1020 long offset = 0; 1021 char *tmp; 1022 int ret = 0; 1023 1024 switch (arg[0]) { 1025 case '$': 1026 ret = parse_probe_vars(arg, type, pcode, end, ctx); 1027 break; 1028 1029 case '%': /* named register */ 1030 if (ctx->flags & (TPARG_FL_TEVENT | TPARG_FL_FPROBE)) { 1031 /* eprobe and fprobe do not handle registers */ 1032 trace_probe_log_err(ctx->offset, BAD_VAR); 1033 break; 1034 } 1035 ret = regs_query_register_offset(arg + 1); 1036 if (ret >= 0) { 1037 code->op = FETCH_OP_REG; 1038 code->param = (unsigned int)ret; 1039 ret = 0; 1040 } else 1041 trace_probe_log_err(ctx->offset, BAD_REG_NAME); 1042 break; 1043 1044 case '@': /* memory, file-offset or symbol */ 1045 if (isdigit(arg[1])) { 1046 ret = kstrtoul(arg + 1, 0, ¶m); 1047 if (ret) { 1048 trace_probe_log_err(ctx->offset, BAD_MEM_ADDR); 1049 break; 1050 } 1051 /* load address */ 1052 code->op = FETCH_OP_IMM; 1053 code->immediate = param; 1054 } else if (arg[1] == '+') { 1055 /* kprobes don't support file offsets */ 1056 if (ctx->flags & TPARG_FL_KERNEL) { 1057 trace_probe_log_err(ctx->offset, FILE_ON_KPROBE); 1058 return -EINVAL; 1059 } 1060 ret = kstrtol(arg + 2, 0, &offset); 1061 if (ret) { 1062 trace_probe_log_err(ctx->offset, BAD_FILE_OFFS); 1063 break; 1064 } 1065 1066 code->op = FETCH_OP_FOFFS; 1067 code->immediate = (unsigned long)offset; // imm64? 1068 } else { 1069 /* uprobes don't support symbols */ 1070 if (!(ctx->flags & TPARG_FL_KERNEL)) { 1071 trace_probe_log_err(ctx->offset, SYM_ON_UPROBE); 1072 return -EINVAL; 1073 } 1074 /* Preserve symbol for updating */ 1075 code->op = FETCH_NOP_SYMBOL; 1076 code->data = kstrdup(arg + 1, GFP_KERNEL); 1077 if (!code->data) 1078 return -ENOMEM; 1079 if (++code == end) { 1080 trace_probe_log_err(ctx->offset, TOO_MANY_OPS); 1081 return -EINVAL; 1082 } 1083 code->op = FETCH_OP_IMM; 1084 code->immediate = 0; 1085 } 1086 /* These are fetching from memory */ 1087 if (++code == end) { 1088 trace_probe_log_err(ctx->offset, TOO_MANY_OPS); 1089 return -EINVAL; 1090 } 1091 *pcode = code; 1092 code->op = FETCH_OP_DEREF; 1093 code->offset = offset; 1094 break; 1095 1096 case '+': /* deref memory */ 1097 case '-': 1098 if (arg[1] == 'u') { 1099 deref = FETCH_OP_UDEREF; 1100 arg[1] = arg[0]; 1101 arg++; 1102 } 1103 if (arg[0] == '+') 1104 arg++; /* Skip '+', because kstrtol() rejects it. */ 1105 tmp = strchr(arg, '('); 1106 if (!tmp) { 1107 trace_probe_log_err(ctx->offset, DEREF_NEED_BRACE); 1108 return -EINVAL; 1109 } 1110 *tmp = '\0'; 1111 ret = kstrtol(arg, 0, &offset); 1112 if (ret) { 1113 trace_probe_log_err(ctx->offset, BAD_DEREF_OFFS); 1114 break; 1115 } 1116 ctx->offset += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0); 1117 arg = tmp + 1; 1118 tmp = strrchr(arg, ')'); 1119 if (!tmp) { 1120 trace_probe_log_err(ctx->offset + strlen(arg), 1121 DEREF_OPEN_BRACE); 1122 return -EINVAL; 1123 } else { 1124 const struct fetch_type *t2 = find_fetch_type(NULL, ctx->flags); 1125 int cur_offs = ctx->offset; 1126 1127 *tmp = '\0'; 1128 ret = parse_probe_arg(arg, t2, &code, end, ctx); 1129 if (ret) 1130 break; 1131 ctx->offset = cur_offs; 1132 if (code->op == FETCH_OP_COMM || 1133 code->op == FETCH_OP_DATA) { 1134 trace_probe_log_err(ctx->offset, COMM_CANT_DEREF); 1135 return -EINVAL; 1136 } 1137 if (++code == end) { 1138 trace_probe_log_err(ctx->offset, TOO_MANY_OPS); 1139 return -EINVAL; 1140 } 1141 *pcode = code; 1142 1143 code->op = deref; 1144 code->offset = offset; 1145 /* Reset the last type if used */ 1146 ctx->last_type = NULL; 1147 } 1148 break; 1149 case '\\': /* Immediate value */ 1150 if (arg[1] == '"') { /* Immediate string */ 1151 ret = __parse_imm_string(arg + 2, &tmp, ctx->offset + 2); 1152 if (ret) 1153 break; 1154 code->op = FETCH_OP_DATA; 1155 code->data = tmp; 1156 } else { 1157 ret = str_to_immediate(arg + 1, &code->immediate); 1158 if (ret) 1159 trace_probe_log_err(ctx->offset + 1, BAD_IMM); 1160 else 1161 code->op = FETCH_OP_IMM; 1162 } 1163 break; 1164 default: 1165 if (isalpha(arg[0]) || arg[0] == '_') { /* BTF variable */ 1166 if (!tparg_is_function_entry(ctx->flags) && 1167 !tparg_is_function_return(ctx->flags)) { 1168 trace_probe_log_err(ctx->offset, NOSUP_BTFARG); 1169 return -EINVAL; 1170 } 1171 ret = parse_btf_arg(arg, pcode, end, ctx); 1172 break; 1173 } 1174 } 1175 if (!ret && code->op == FETCH_OP_NOP) { 1176 /* Parsed, but do not find fetch method */ 1177 trace_probe_log_err(ctx->offset, BAD_FETCH_ARG); 1178 ret = -EINVAL; 1179 } 1180 return ret; 1181 } 1182 1183 #define BYTES_TO_BITS(nb) ((BITS_PER_LONG * (nb)) / sizeof(long)) 1184 1185 /* Bitfield type needs to be parsed into a fetch function */ 1186 static int __parse_bitfield_probe_arg(const char *bf, 1187 const struct fetch_type *t, 1188 struct fetch_insn **pcode) 1189 { 1190 struct fetch_insn *code = *pcode; 1191 unsigned long bw, bo; 1192 char *tail; 1193 1194 if (*bf != 'b') 1195 return 0; 1196 1197 bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */ 1198 1199 if (bw == 0 || *tail != '@') 1200 return -EINVAL; 1201 1202 bf = tail + 1; 1203 bo = simple_strtoul(bf, &tail, 0); 1204 1205 if (tail == bf || *tail != '/') 1206 return -EINVAL; 1207 code++; 1208 if (code->op != FETCH_OP_NOP) 1209 return -EINVAL; 1210 *pcode = code; 1211 1212 code->op = FETCH_OP_MOD_BF; 1213 code->lshift = BYTES_TO_BITS(t->size) - (bw + bo); 1214 code->rshift = BYTES_TO_BITS(t->size) - bw; 1215 code->basesize = t->size; 1216 1217 return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0; 1218 } 1219 1220 /* Split type part from @arg and return it. */ 1221 static char *parse_probe_arg_type(char *arg, struct probe_arg *parg, 1222 struct traceprobe_parse_context *ctx) 1223 { 1224 char *t = NULL, *t2, *t3; 1225 int offs; 1226 1227 t = strchr(arg, ':'); 1228 if (t) { 1229 *t++ = '\0'; 1230 t2 = strchr(t, '['); 1231 if (t2) { 1232 *t2++ = '\0'; 1233 t3 = strchr(t2, ']'); 1234 if (!t3) { 1235 offs = t2 + strlen(t2) - arg; 1236 1237 trace_probe_log_err(ctx->offset + offs, 1238 ARRAY_NO_CLOSE); 1239 return ERR_PTR(-EINVAL); 1240 } else if (t3[1] != '\0') { 1241 trace_probe_log_err(ctx->offset + t3 + 1 - arg, 1242 BAD_ARRAY_SUFFIX); 1243 return ERR_PTR(-EINVAL); 1244 } 1245 *t3 = '\0'; 1246 if (kstrtouint(t2, 0, &parg->count) || !parg->count) { 1247 trace_probe_log_err(ctx->offset + t2 - arg, 1248 BAD_ARRAY_NUM); 1249 return ERR_PTR(-EINVAL); 1250 } 1251 if (parg->count > MAX_ARRAY_LEN) { 1252 trace_probe_log_err(ctx->offset + t2 - arg, 1253 ARRAY_TOO_BIG); 1254 return ERR_PTR(-EINVAL); 1255 } 1256 } 1257 } 1258 offs = t ? t - arg : 0; 1259 1260 /* 1261 * Since $comm and immediate string can not be dereferenced, 1262 * we can find those by strcmp. But ignore for eprobes. 1263 */ 1264 if (!(ctx->flags & TPARG_FL_TEVENT) && 1265 (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 || 1266 strncmp(arg, "\\\"", 2) == 0)) { 1267 /* The type of $comm must be "string", and not an array type. */ 1268 if (parg->count || (t && strcmp(t, "string"))) { 1269 trace_probe_log_err(ctx->offset + offs, NEED_STRING_TYPE); 1270 return ERR_PTR(-EINVAL); 1271 } 1272 parg->type = find_fetch_type("string", ctx->flags); 1273 } else 1274 parg->type = find_fetch_type(t, ctx->flags); 1275 1276 if (!parg->type) { 1277 trace_probe_log_err(ctx->offset + offs, BAD_TYPE); 1278 return ERR_PTR(-EINVAL); 1279 } 1280 1281 return t; 1282 } 1283 1284 /* After parsing, adjust the fetch_insn according to the probe_arg */ 1285 static int finalize_fetch_insn(struct fetch_insn *code, 1286 struct probe_arg *parg, 1287 char *type, 1288 int type_offset, 1289 struct traceprobe_parse_context *ctx) 1290 { 1291 struct fetch_insn *scode; 1292 int ret; 1293 1294 /* Store operation */ 1295 if (parg->type->is_string) { 1296 /* Check bad combination of the type and the last fetch_insn. */ 1297 if (!strcmp(parg->type->name, "symstr")) { 1298 if (code->op != FETCH_OP_REG && code->op != FETCH_OP_STACK && 1299 code->op != FETCH_OP_RETVAL && code->op != FETCH_OP_ARG && 1300 code->op != FETCH_OP_DEREF && code->op != FETCH_OP_TP_ARG) { 1301 trace_probe_log_err(ctx->offset + type_offset, 1302 BAD_SYMSTRING); 1303 return -EINVAL; 1304 } 1305 } else { 1306 if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF && 1307 code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM && 1308 code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) { 1309 trace_probe_log_err(ctx->offset + type_offset, 1310 BAD_STRING); 1311 return -EINVAL; 1312 } 1313 } 1314 1315 if (!strcmp(parg->type->name, "symstr") || 1316 (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM || 1317 code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG || 1318 parg->count) { 1319 /* 1320 * IMM, DATA and COMM is pointing actual address, those 1321 * must be kept, and if parg->count != 0, this is an 1322 * array of string pointers instead of string address 1323 * itself. 1324 * For the symstr, it doesn't need to dereference, thus 1325 * it just get the value. 1326 */ 1327 code++; 1328 if (code->op != FETCH_OP_NOP) { 1329 trace_probe_log_err(ctx->offset, TOO_MANY_OPS); 1330 return -EINVAL; 1331 } 1332 } 1333 1334 /* If op == DEREF, replace it with STRING */ 1335 if (!strcmp(parg->type->name, "ustring") || 1336 code->op == FETCH_OP_UDEREF) 1337 code->op = FETCH_OP_ST_USTRING; 1338 else if (!strcmp(parg->type->name, "symstr")) 1339 code->op = FETCH_OP_ST_SYMSTR; 1340 else 1341 code->op = FETCH_OP_ST_STRING; 1342 code->size = parg->type->size; 1343 parg->dynamic = true; 1344 } else if (code->op == FETCH_OP_DEREF) { 1345 code->op = FETCH_OP_ST_MEM; 1346 code->size = parg->type->size; 1347 } else if (code->op == FETCH_OP_UDEREF) { 1348 code->op = FETCH_OP_ST_UMEM; 1349 code->size = parg->type->size; 1350 } else { 1351 code++; 1352 if (code->op != FETCH_OP_NOP) { 1353 trace_probe_log_err(ctx->offset, TOO_MANY_OPS); 1354 return -E2BIG; 1355 } 1356 code->op = FETCH_OP_ST_RAW; 1357 code->size = parg->type->size; 1358 } 1359 1360 /* Save storing fetch_insn. */ 1361 scode = code; 1362 1363 /* Modify operation */ 1364 if (type != NULL) { 1365 /* Bitfield needs a special fetch_insn. */ 1366 ret = __parse_bitfield_probe_arg(type, parg->type, &code); 1367 if (ret) { 1368 trace_probe_log_err(ctx->offset + type_offset, BAD_BITFIELD); 1369 return ret; 1370 } 1371 } else if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) && 1372 ctx->last_type) { 1373 /* If user not specified the type, try parsing BTF bitfield. */ 1374 ret = parse_btf_bitfield(&code, ctx); 1375 if (ret) 1376 return ret; 1377 } 1378 1379 /* Loop(Array) operation */ 1380 if (parg->count) { 1381 if (scode->op != FETCH_OP_ST_MEM && 1382 scode->op != FETCH_OP_ST_STRING && 1383 scode->op != FETCH_OP_ST_USTRING) { 1384 trace_probe_log_err(ctx->offset + type_offset, BAD_STRING); 1385 return -EINVAL; 1386 } 1387 code++; 1388 if (code->op != FETCH_OP_NOP) { 1389 trace_probe_log_err(ctx->offset, TOO_MANY_OPS); 1390 return -E2BIG; 1391 } 1392 code->op = FETCH_OP_LP_ARRAY; 1393 code->param = parg->count; 1394 } 1395 1396 /* Finalize the fetch_insn array. */ 1397 code++; 1398 code->op = FETCH_OP_END; 1399 1400 return 0; 1401 } 1402 1403 /* String length checking wrapper */ 1404 static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size, 1405 struct probe_arg *parg, 1406 struct traceprobe_parse_context *ctx) 1407 { 1408 struct fetch_insn *code, *tmp = NULL; 1409 char *type, *arg; 1410 int ret, len; 1411 1412 len = strlen(argv); 1413 if (len > MAX_ARGSTR_LEN) { 1414 trace_probe_log_err(ctx->offset, ARG_TOO_LONG); 1415 return -E2BIG; 1416 } else if (len == 0) { 1417 trace_probe_log_err(ctx->offset, NO_ARG_BODY); 1418 return -EINVAL; 1419 } 1420 1421 arg = kstrdup(argv, GFP_KERNEL); 1422 if (!arg) 1423 return -ENOMEM; 1424 1425 parg->comm = kstrdup(arg, GFP_KERNEL); 1426 if (!parg->comm) { 1427 ret = -ENOMEM; 1428 goto out; 1429 } 1430 1431 type = parse_probe_arg_type(arg, parg, ctx); 1432 if (IS_ERR(type)) { 1433 ret = PTR_ERR(type); 1434 goto out; 1435 } 1436 1437 code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL); 1438 if (!code) { 1439 ret = -ENOMEM; 1440 goto out; 1441 } 1442 code[FETCH_INSN_MAX - 1].op = FETCH_OP_END; 1443 1444 ctx->last_type = NULL; 1445 ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1], 1446 ctx); 1447 if (ret < 0) 1448 goto fail; 1449 1450 /* Update storing type if BTF is available */ 1451 if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) && 1452 ctx->last_type) { 1453 if (!type) { 1454 parg->type = find_fetch_type_from_btf_type(ctx); 1455 } else if (strstr(type, "string")) { 1456 ret = check_prepare_btf_string_fetch(type, &code, ctx); 1457 if (ret) 1458 goto fail; 1459 } 1460 } 1461 parg->offset = *size; 1462 *size += parg->type->size * (parg->count ?: 1); 1463 1464 if (parg->count) { 1465 len = strlen(parg->type->fmttype) + 6; 1466 parg->fmt = kmalloc(len, GFP_KERNEL); 1467 if (!parg->fmt) { 1468 ret = -ENOMEM; 1469 goto out; 1470 } 1471 snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype, 1472 parg->count); 1473 } 1474 1475 ret = finalize_fetch_insn(code, parg, type, type ? type - arg : 0, ctx); 1476 if (ret < 0) 1477 goto fail; 1478 1479 for (; code < tmp + FETCH_INSN_MAX; code++) 1480 if (code->op == FETCH_OP_END) 1481 break; 1482 /* Shrink down the code buffer */ 1483 parg->code = kcalloc(code - tmp + 1, sizeof(*code), GFP_KERNEL); 1484 if (!parg->code) 1485 ret = -ENOMEM; 1486 else 1487 memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1)); 1488 1489 fail: 1490 if (ret < 0) { 1491 for (code = tmp; code < tmp + FETCH_INSN_MAX; code++) 1492 if (code->op == FETCH_NOP_SYMBOL || 1493 code->op == FETCH_OP_DATA) 1494 kfree(code->data); 1495 } 1496 kfree(tmp); 1497 out: 1498 kfree(arg); 1499 1500 return ret; 1501 } 1502 1503 /* Return 1 if name is reserved or already used by another argument */ 1504 static int traceprobe_conflict_field_name(const char *name, 1505 struct probe_arg *args, int narg) 1506 { 1507 int i; 1508 1509 for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++) 1510 if (strcmp(reserved_field_names[i], name) == 0) 1511 return 1; 1512 1513 for (i = 0; i < narg; i++) 1514 if (strcmp(args[i].name, name) == 0) 1515 return 1; 1516 1517 return 0; 1518 } 1519 1520 static char *generate_probe_arg_name(const char *arg, int idx) 1521 { 1522 char *name = NULL; 1523 const char *end; 1524 1525 /* 1526 * If argument name is omitted, try arg as a name (BTF variable) 1527 * or "argN". 1528 */ 1529 if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) { 1530 end = strchr(arg, ':'); 1531 if (!end) 1532 end = arg + strlen(arg); 1533 1534 name = kmemdup_nul(arg, end - arg, GFP_KERNEL); 1535 if (!name || !is_good_name(name)) { 1536 kfree(name); 1537 name = NULL; 1538 } 1539 } 1540 1541 if (!name) 1542 name = kasprintf(GFP_KERNEL, "arg%d", idx + 1); 1543 1544 return name; 1545 } 1546 1547 int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg, 1548 struct traceprobe_parse_context *ctx) 1549 { 1550 struct probe_arg *parg = &tp->args[i]; 1551 const char *body; 1552 1553 ctx->tp = tp; 1554 body = strchr(arg, '='); 1555 if (body) { 1556 if (body - arg > MAX_ARG_NAME_LEN) { 1557 trace_probe_log_err(0, ARG_NAME_TOO_LONG); 1558 return -EINVAL; 1559 } else if (body == arg) { 1560 trace_probe_log_err(0, NO_ARG_NAME); 1561 return -EINVAL; 1562 } 1563 parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL); 1564 body++; 1565 } else { 1566 parg->name = generate_probe_arg_name(arg, i); 1567 body = arg; 1568 } 1569 if (!parg->name) 1570 return -ENOMEM; 1571 1572 if (!is_good_name(parg->name)) { 1573 trace_probe_log_err(0, BAD_ARG_NAME); 1574 return -EINVAL; 1575 } 1576 if (traceprobe_conflict_field_name(parg->name, tp->args, i)) { 1577 trace_probe_log_err(0, USED_ARG_NAME); 1578 return -EINVAL; 1579 } 1580 ctx->offset = body - arg; 1581 /* Parse fetch argument */ 1582 return traceprobe_parse_probe_arg_body(body, &tp->size, parg, ctx); 1583 } 1584 1585 void traceprobe_free_probe_arg(struct probe_arg *arg) 1586 { 1587 struct fetch_insn *code = arg->code; 1588 1589 while (code && code->op != FETCH_OP_END) { 1590 if (code->op == FETCH_NOP_SYMBOL || 1591 code->op == FETCH_OP_DATA) 1592 kfree(code->data); 1593 code++; 1594 } 1595 kfree(arg->code); 1596 kfree(arg->name); 1597 kfree(arg->comm); 1598 kfree(arg->fmt); 1599 } 1600 1601 static int argv_has_var_arg(int argc, const char *argv[], int *args_idx, 1602 struct traceprobe_parse_context *ctx) 1603 { 1604 int i, found = 0; 1605 1606 for (i = 0; i < argc; i++) 1607 if (str_has_prefix(argv[i], "$arg")) { 1608 trace_probe_log_set_index(i + 2); 1609 1610 if (!tparg_is_function_entry(ctx->flags) && 1611 !tparg_is_function_return(ctx->flags)) { 1612 trace_probe_log_err(0, NOFENTRY_ARGS); 1613 return -EINVAL; 1614 } 1615 1616 if (isdigit(argv[i][4])) { 1617 found = 1; 1618 continue; 1619 } 1620 1621 if (argv[i][4] != '*') { 1622 trace_probe_log_err(0, BAD_VAR); 1623 return -EINVAL; 1624 } 1625 1626 if (*args_idx >= 0 && *args_idx < argc) { 1627 trace_probe_log_err(0, DOUBLE_ARGS); 1628 return -EINVAL; 1629 } 1630 found = 1; 1631 *args_idx = i; 1632 } 1633 1634 return found; 1635 } 1636 1637 static int sprint_nth_btf_arg(int idx, const char *type, 1638 char *buf, int bufsize, 1639 struct traceprobe_parse_context *ctx) 1640 { 1641 const char *name; 1642 int ret; 1643 1644 if (idx >= ctx->nr_params) { 1645 trace_probe_log_err(0, NO_BTFARG); 1646 return -ENOENT; 1647 } 1648 name = btf_name_by_offset(ctx->btf, ctx->params[idx].name_off); 1649 if (!name) { 1650 trace_probe_log_err(0, NO_BTF_ENTRY); 1651 return -ENOENT; 1652 } 1653 ret = snprintf(buf, bufsize, "%s%s", name, type); 1654 if (ret >= bufsize) { 1655 trace_probe_log_err(0, ARGS_2LONG); 1656 return -E2BIG; 1657 } 1658 return ret; 1659 } 1660 1661 /* Return new_argv which must be freed after use */ 1662 const char **traceprobe_expand_meta_args(int argc, const char *argv[], 1663 int *new_argc, char *buf, int bufsize, 1664 struct traceprobe_parse_context *ctx) 1665 { 1666 const struct btf_param *params = NULL; 1667 int i, j, n, used, ret, args_idx = -1; 1668 const char **new_argv = NULL; 1669 1670 ret = argv_has_var_arg(argc, argv, &args_idx, ctx); 1671 if (ret < 0) 1672 return ERR_PTR(ret); 1673 1674 if (!ret) { 1675 *new_argc = argc; 1676 return NULL; 1677 } 1678 1679 ret = query_btf_context(ctx); 1680 if (ret < 0 || ctx->nr_params == 0) { 1681 if (args_idx != -1) { 1682 /* $arg* requires BTF info */ 1683 trace_probe_log_err(0, NOSUP_BTFARG); 1684 return (const char **)params; 1685 } 1686 *new_argc = argc; 1687 return NULL; 1688 } 1689 1690 if (args_idx >= 0) 1691 *new_argc = argc + ctx->nr_params - 1; 1692 else 1693 *new_argc = argc; 1694 1695 new_argv = kcalloc(*new_argc, sizeof(char *), GFP_KERNEL); 1696 if (!new_argv) 1697 return ERR_PTR(-ENOMEM); 1698 1699 used = 0; 1700 for (i = 0, j = 0; i < argc; i++) { 1701 trace_probe_log_set_index(i + 2); 1702 if (i == args_idx) { 1703 for (n = 0; n < ctx->nr_params; n++) { 1704 ret = sprint_nth_btf_arg(n, "", buf + used, 1705 bufsize - used, ctx); 1706 if (ret < 0) 1707 goto error; 1708 1709 new_argv[j++] = buf + used; 1710 used += ret + 1; 1711 } 1712 continue; 1713 } 1714 1715 if (str_has_prefix(argv[i], "$arg")) { 1716 char *type = NULL; 1717 1718 n = simple_strtoul(argv[i] + 4, &type, 10); 1719 if (type && !(*type == ':' || *type == '\0')) { 1720 trace_probe_log_err(0, BAD_VAR); 1721 ret = -ENOENT; 1722 goto error; 1723 } 1724 /* Note: $argN starts from $arg1 */ 1725 ret = sprint_nth_btf_arg(n - 1, type, buf + used, 1726 bufsize - used, ctx); 1727 if (ret < 0) 1728 goto error; 1729 new_argv[j++] = buf + used; 1730 used += ret + 1; 1731 } else 1732 new_argv[j++] = argv[i]; 1733 } 1734 1735 return new_argv; 1736 1737 error: 1738 kfree(new_argv); 1739 return ERR_PTR(ret); 1740 } 1741 1742 void traceprobe_finish_parse(struct traceprobe_parse_context *ctx) 1743 { 1744 clear_btf_context(ctx); 1745 } 1746 1747 int traceprobe_update_arg(struct probe_arg *arg) 1748 { 1749 struct fetch_insn *code = arg->code; 1750 long offset; 1751 char *tmp; 1752 char c; 1753 int ret = 0; 1754 1755 while (code && code->op != FETCH_OP_END) { 1756 if (code->op == FETCH_NOP_SYMBOL) { 1757 if (code[1].op != FETCH_OP_IMM) 1758 return -EINVAL; 1759 1760 tmp = strpbrk(code->data, "+-"); 1761 if (tmp) 1762 c = *tmp; 1763 ret = traceprobe_split_symbol_offset(code->data, 1764 &offset); 1765 if (ret) 1766 return ret; 1767 1768 code[1].immediate = 1769 (unsigned long)kallsyms_lookup_name(code->data); 1770 if (tmp) 1771 *tmp = c; 1772 if (!code[1].immediate) 1773 return -ENOENT; 1774 code[1].immediate += offset; 1775 } 1776 code++; 1777 } 1778 return 0; 1779 } 1780 1781 /* When len=0, we just calculate the needed length */ 1782 #define LEN_OR_ZERO (len ? len - pos : 0) 1783 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len, 1784 enum probe_print_type ptype) 1785 { 1786 struct probe_arg *parg; 1787 int i, j; 1788 int pos = 0; 1789 const char *fmt, *arg; 1790 1791 switch (ptype) { 1792 case PROBE_PRINT_NORMAL: 1793 fmt = "(%lx)"; 1794 arg = ", REC->" FIELD_STRING_IP; 1795 break; 1796 case PROBE_PRINT_RETURN: 1797 fmt = "(%lx <- %lx)"; 1798 arg = ", REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP; 1799 break; 1800 case PROBE_PRINT_EVENT: 1801 fmt = ""; 1802 arg = ""; 1803 break; 1804 default: 1805 WARN_ON_ONCE(1); 1806 return 0; 1807 } 1808 1809 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt); 1810 1811 for (i = 0; i < tp->nr_args; i++) { 1812 parg = tp->args + i; 1813 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name); 1814 if (parg->count) { 1815 pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s", 1816 parg->type->fmt); 1817 for (j = 1; j < parg->count; j++) 1818 pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s", 1819 parg->type->fmt); 1820 pos += snprintf(buf + pos, LEN_OR_ZERO, "}"); 1821 } else 1822 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s", 1823 parg->type->fmt); 1824 } 1825 1826 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", arg); 1827 1828 for (i = 0; i < tp->nr_args; i++) { 1829 parg = tp->args + i; 1830 if (parg->count) { 1831 if (parg->type->is_string) 1832 fmt = ", __get_str(%s[%d])"; 1833 else 1834 fmt = ", REC->%s[%d]"; 1835 for (j = 0; j < parg->count; j++) 1836 pos += snprintf(buf + pos, LEN_OR_ZERO, 1837 fmt, parg->name, j); 1838 } else { 1839 if (parg->type->is_string) 1840 fmt = ", __get_str(%s)"; 1841 else 1842 fmt = ", REC->%s"; 1843 pos += snprintf(buf + pos, LEN_OR_ZERO, 1844 fmt, parg->name); 1845 } 1846 } 1847 1848 /* return the length of print_fmt */ 1849 return pos; 1850 } 1851 #undef LEN_OR_ZERO 1852 1853 int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype) 1854 { 1855 struct trace_event_call *call = trace_probe_event_call(tp); 1856 int len; 1857 char *print_fmt; 1858 1859 /* First: called with 0 length to calculate the needed length */ 1860 len = __set_print_fmt(tp, NULL, 0, ptype); 1861 print_fmt = kmalloc(len + 1, GFP_KERNEL); 1862 if (!print_fmt) 1863 return -ENOMEM; 1864 1865 /* Second: actually write the @print_fmt */ 1866 __set_print_fmt(tp, print_fmt, len + 1, ptype); 1867 call->print_fmt = print_fmt; 1868 1869 return 0; 1870 } 1871 1872 int traceprobe_define_arg_fields(struct trace_event_call *event_call, 1873 size_t offset, struct trace_probe *tp) 1874 { 1875 int ret, i; 1876 1877 /* Set argument names as fields */ 1878 for (i = 0; i < tp->nr_args; i++) { 1879 struct probe_arg *parg = &tp->args[i]; 1880 const char *fmt = parg->type->fmttype; 1881 int size = parg->type->size; 1882 1883 if (parg->fmt) 1884 fmt = parg->fmt; 1885 if (parg->count) 1886 size *= parg->count; 1887 ret = trace_define_field(event_call, fmt, parg->name, 1888 offset + parg->offset, size, 1889 parg->type->is_signed, 1890 FILTER_OTHER); 1891 if (ret) 1892 return ret; 1893 } 1894 return 0; 1895 } 1896 1897 static void trace_probe_event_free(struct trace_probe_event *tpe) 1898 { 1899 kfree(tpe->class.system); 1900 kfree(tpe->call.name); 1901 kfree(tpe->call.print_fmt); 1902 kfree(tpe); 1903 } 1904 1905 int trace_probe_append(struct trace_probe *tp, struct trace_probe *to) 1906 { 1907 if (trace_probe_has_sibling(tp)) 1908 return -EBUSY; 1909 1910 list_del_init(&tp->list); 1911 trace_probe_event_free(tp->event); 1912 1913 tp->event = to->event; 1914 list_add_tail(&tp->list, trace_probe_probe_list(to)); 1915 1916 return 0; 1917 } 1918 1919 void trace_probe_unlink(struct trace_probe *tp) 1920 { 1921 list_del_init(&tp->list); 1922 if (list_empty(trace_probe_probe_list(tp))) 1923 trace_probe_event_free(tp->event); 1924 tp->event = NULL; 1925 } 1926 1927 void trace_probe_cleanup(struct trace_probe *tp) 1928 { 1929 int i; 1930 1931 for (i = 0; i < tp->nr_args; i++) 1932 traceprobe_free_probe_arg(&tp->args[i]); 1933 1934 if (tp->entry_arg) { 1935 kfree(tp->entry_arg->code); 1936 kfree(tp->entry_arg); 1937 tp->entry_arg = NULL; 1938 } 1939 1940 if (tp->event) 1941 trace_probe_unlink(tp); 1942 } 1943 1944 int trace_probe_init(struct trace_probe *tp, const char *event, 1945 const char *group, bool alloc_filter, int nargs) 1946 { 1947 struct trace_event_call *call; 1948 size_t size = sizeof(struct trace_probe_event); 1949 int ret = 0; 1950 1951 if (!event || !group) 1952 return -EINVAL; 1953 1954 if (alloc_filter) 1955 size += sizeof(struct trace_uprobe_filter); 1956 1957 tp->event = kzalloc(size, GFP_KERNEL); 1958 if (!tp->event) 1959 return -ENOMEM; 1960 1961 INIT_LIST_HEAD(&tp->event->files); 1962 INIT_LIST_HEAD(&tp->event->class.fields); 1963 INIT_LIST_HEAD(&tp->event->probes); 1964 INIT_LIST_HEAD(&tp->list); 1965 list_add(&tp->list, &tp->event->probes); 1966 1967 call = trace_probe_event_call(tp); 1968 call->class = &tp->event->class; 1969 call->name = kstrdup(event, GFP_KERNEL); 1970 if (!call->name) { 1971 ret = -ENOMEM; 1972 goto error; 1973 } 1974 1975 tp->event->class.system = kstrdup(group, GFP_KERNEL); 1976 if (!tp->event->class.system) { 1977 ret = -ENOMEM; 1978 goto error; 1979 } 1980 1981 tp->nr_args = nargs; 1982 /* Make sure pointers in args[] are NULL */ 1983 if (nargs) 1984 memset(tp->args, 0, sizeof(tp->args[0]) * nargs); 1985 1986 return 0; 1987 1988 error: 1989 trace_probe_cleanup(tp); 1990 return ret; 1991 } 1992 1993 static struct trace_event_call * 1994 find_trace_event_call(const char *system, const char *event_name) 1995 { 1996 struct trace_event_call *tp_event; 1997 const char *name; 1998 1999 list_for_each_entry(tp_event, &ftrace_events, list) { 2000 if (!tp_event->class->system || 2001 strcmp(system, tp_event->class->system)) 2002 continue; 2003 name = trace_event_name(tp_event); 2004 if (!name || strcmp(event_name, name)) 2005 continue; 2006 return tp_event; 2007 } 2008 2009 return NULL; 2010 } 2011 2012 int trace_probe_register_event_call(struct trace_probe *tp) 2013 { 2014 struct trace_event_call *call = trace_probe_event_call(tp); 2015 int ret; 2016 2017 lockdep_assert_held(&event_mutex); 2018 2019 if (find_trace_event_call(trace_probe_group_name(tp), 2020 trace_probe_name(tp))) 2021 return -EEXIST; 2022 2023 ret = register_trace_event(&call->event); 2024 if (!ret) 2025 return -ENODEV; 2026 2027 ret = trace_add_event_call(call); 2028 if (ret) 2029 unregister_trace_event(&call->event); 2030 2031 return ret; 2032 } 2033 2034 int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file) 2035 { 2036 struct event_file_link *link; 2037 2038 link = kmalloc(sizeof(*link), GFP_KERNEL); 2039 if (!link) 2040 return -ENOMEM; 2041 2042 link->file = file; 2043 INIT_LIST_HEAD(&link->list); 2044 list_add_tail_rcu(&link->list, &tp->event->files); 2045 trace_probe_set_flag(tp, TP_FLAG_TRACE); 2046 return 0; 2047 } 2048 2049 struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp, 2050 struct trace_event_file *file) 2051 { 2052 struct event_file_link *link; 2053 2054 trace_probe_for_each_link(link, tp) { 2055 if (link->file == file) 2056 return link; 2057 } 2058 2059 return NULL; 2060 } 2061 2062 int trace_probe_remove_file(struct trace_probe *tp, 2063 struct trace_event_file *file) 2064 { 2065 struct event_file_link *link; 2066 2067 link = trace_probe_get_file_link(tp, file); 2068 if (!link) 2069 return -ENOENT; 2070 2071 list_del_rcu(&link->list); 2072 kvfree_rcu_mightsleep(link); 2073 2074 if (list_empty(&tp->event->files)) 2075 trace_probe_clear_flag(tp, TP_FLAG_TRACE); 2076 2077 return 0; 2078 } 2079 2080 /* 2081 * Return the smallest index of different type argument (start from 1). 2082 * If all argument types and name are same, return 0. 2083 */ 2084 int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b) 2085 { 2086 int i; 2087 2088 /* In case of more arguments */ 2089 if (a->nr_args < b->nr_args) 2090 return a->nr_args + 1; 2091 if (a->nr_args > b->nr_args) 2092 return b->nr_args + 1; 2093 2094 for (i = 0; i < a->nr_args; i++) { 2095 if ((b->nr_args <= i) || 2096 ((a->args[i].type != b->args[i].type) || 2097 (a->args[i].count != b->args[i].count) || 2098 strcmp(a->args[i].name, b->args[i].name))) 2099 return i + 1; 2100 } 2101 2102 return 0; 2103 } 2104 2105 bool trace_probe_match_command_args(struct trace_probe *tp, 2106 int argc, const char **argv) 2107 { 2108 char buf[MAX_ARGSTR_LEN + 1]; 2109 int i; 2110 2111 if (tp->nr_args < argc) 2112 return false; 2113 2114 for (i = 0; i < argc; i++) { 2115 snprintf(buf, sizeof(buf), "%s=%s", 2116 tp->args[i].name, tp->args[i].comm); 2117 if (strcmp(buf, argv[i])) 2118 return false; 2119 } 2120 return true; 2121 } 2122 2123 int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **)) 2124 { 2125 int argc = 0, ret = 0; 2126 char **argv; 2127 2128 argv = argv_split(GFP_KERNEL, raw_command, &argc); 2129 if (!argv) 2130 return -ENOMEM; 2131 2132 if (argc) 2133 ret = createfn(argc, (const char **)argv); 2134 2135 argv_free(argv); 2136 2137 return ret; 2138 } 2139 2140 int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_args, 2141 u8 *data, void *field) 2142 { 2143 void *p; 2144 int i, j; 2145 2146 for (i = 0; i < nr_args; i++) { 2147 struct probe_arg *a = args + i; 2148 2149 trace_seq_printf(s, " %s=", a->name); 2150 if (likely(!a->count)) { 2151 if (!a->type->print(s, data + a->offset, field)) 2152 return -ENOMEM; 2153 continue; 2154 } 2155 trace_seq_putc(s, '{'); 2156 p = data + a->offset; 2157 for (j = 0; j < a->count; j++) { 2158 if (!a->type->print(s, p, field)) 2159 return -ENOMEM; 2160 trace_seq_putc(s, j == a->count - 1 ? '}' : ','); 2161 p += a->type->size; 2162 } 2163 } 2164 return 0; 2165 } 2166