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 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 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long)) 158 159 static int parse_probe_vars(char *arg, const struct fetch_type *t, 160 struct fetch_insn *code, unsigned int flags) 161 { 162 int ret = 0; 163 unsigned long param; 164 165 if (strcmp(arg, "retval") == 0) { 166 if (flags & TPARG_FL_RETURN) 167 code->op = FETCH_OP_RETVAL; 168 else 169 ret = -EINVAL; 170 } else if (strncmp(arg, "stack", 5) == 0) { 171 if (arg[5] == '\0') { 172 code->op = FETCH_OP_STACKP; 173 } else if (isdigit(arg[5])) { 174 ret = kstrtoul(arg + 5, 10, ¶m); 175 if (ret || ((flags & TPARG_FL_KERNEL) && 176 param > PARAM_MAX_STACK)) 177 ret = -EINVAL; 178 else { 179 code->op = FETCH_OP_STACK; 180 code->param = (unsigned int)param; 181 } 182 } else 183 ret = -EINVAL; 184 } else if (strcmp(arg, "comm") == 0) { 185 code->op = FETCH_OP_COMM; 186 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API 187 } else if (((flags & TPARG_FL_MASK) == 188 (TPARG_FL_KERNEL | TPARG_FL_FENTRY)) && 189 strncmp(arg, "arg", 3) == 0) { 190 if (!isdigit(arg[3])) 191 return -EINVAL; 192 ret = kstrtoul(arg + 3, 10, ¶m); 193 if (ret || !param || param > PARAM_MAX_STACK) 194 return -EINVAL; 195 code->op = FETCH_OP_ARG; 196 code->param = (unsigned int)param - 1; 197 #endif 198 } else 199 ret = -EINVAL; 200 201 return ret; 202 } 203 204 /* Recursive argument parser */ 205 static int 206 parse_probe_arg(char *arg, const struct fetch_type *type, 207 struct fetch_insn **pcode, struct fetch_insn *end, 208 unsigned int flags) 209 { 210 struct fetch_insn *code = *pcode; 211 unsigned long param; 212 long offset = 0; 213 char *tmp; 214 int ret = 0; 215 216 switch (arg[0]) { 217 case '$': 218 ret = parse_probe_vars(arg + 1, type, code, flags); 219 break; 220 221 case '%': /* named register */ 222 ret = regs_query_register_offset(arg + 1); 223 if (ret >= 0) { 224 code->op = FETCH_OP_REG; 225 code->param = (unsigned int)ret; 226 ret = 0; 227 } 228 break; 229 230 case '@': /* memory, file-offset or symbol */ 231 if (isdigit(arg[1])) { 232 ret = kstrtoul(arg + 1, 0, ¶m); 233 if (ret) 234 break; 235 /* load address */ 236 code->op = FETCH_OP_IMM; 237 code->immediate = param; 238 } else if (arg[1] == '+') { 239 /* kprobes don't support file offsets */ 240 if (flags & TPARG_FL_KERNEL) 241 return -EINVAL; 242 243 ret = kstrtol(arg + 2, 0, &offset); 244 if (ret) 245 break; 246 247 code->op = FETCH_OP_FOFFS; 248 code->immediate = (unsigned long)offset; // imm64? 249 } else { 250 /* uprobes don't support symbols */ 251 if (!(flags & TPARG_FL_KERNEL)) 252 return -EINVAL; 253 254 /* Preserve symbol for updating */ 255 code->op = FETCH_NOP_SYMBOL; 256 code->data = kstrdup(arg + 1, GFP_KERNEL); 257 if (!code->data) 258 return -ENOMEM; 259 if (++code == end) 260 return -E2BIG; 261 262 code->op = FETCH_OP_IMM; 263 code->immediate = 0; 264 } 265 /* These are fetching from memory */ 266 if (++code == end) 267 return -E2BIG; 268 *pcode = code; 269 code->op = FETCH_OP_DEREF; 270 code->offset = offset; 271 break; 272 273 case '+': /* deref memory */ 274 arg++; /* Skip '+', because kstrtol() rejects it. */ 275 case '-': 276 tmp = strchr(arg, '('); 277 if (!tmp) 278 return -EINVAL; 279 280 *tmp = '\0'; 281 ret = kstrtol(arg, 0, &offset); 282 if (ret) 283 break; 284 285 arg = tmp + 1; 286 tmp = strrchr(arg, ')'); 287 288 if (tmp) { 289 const struct fetch_type *t2 = find_fetch_type(NULL); 290 291 *tmp = '\0'; 292 ret = parse_probe_arg(arg, t2, &code, end, flags); 293 if (ret) 294 break; 295 if (code->op == FETCH_OP_COMM) 296 return -EINVAL; 297 if (++code == end) 298 return -E2BIG; 299 *pcode = code; 300 301 code->op = FETCH_OP_DEREF; 302 code->offset = offset; 303 } 304 break; 305 } 306 if (!ret && code->op == FETCH_OP_NOP) { 307 /* Parsed, but do not find fetch method */ 308 ret = -EINVAL; 309 } 310 return ret; 311 } 312 313 #define BYTES_TO_BITS(nb) ((BITS_PER_LONG * (nb)) / sizeof(long)) 314 315 /* Bitfield type needs to be parsed into a fetch function */ 316 static int __parse_bitfield_probe_arg(const char *bf, 317 const struct fetch_type *t, 318 struct fetch_insn **pcode) 319 { 320 struct fetch_insn *code = *pcode; 321 unsigned long bw, bo; 322 char *tail; 323 324 if (*bf != 'b') 325 return 0; 326 327 bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */ 328 329 if (bw == 0 || *tail != '@') 330 return -EINVAL; 331 332 bf = tail + 1; 333 bo = simple_strtoul(bf, &tail, 0); 334 335 if (tail == bf || *tail != '/') 336 return -EINVAL; 337 code++; 338 if (code->op != FETCH_OP_NOP) 339 return -E2BIG; 340 *pcode = code; 341 342 code->op = FETCH_OP_MOD_BF; 343 code->lshift = BYTES_TO_BITS(t->size) - (bw + bo); 344 code->rshift = BYTES_TO_BITS(t->size) - bw; 345 code->basesize = t->size; 346 347 return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0; 348 } 349 350 /* String length checking wrapper */ 351 int traceprobe_parse_probe_arg(char *arg, ssize_t *size, 352 struct probe_arg *parg, unsigned int flags) 353 { 354 struct fetch_insn *code, *scode, *tmp = NULL; 355 char *t, *t2; 356 int ret, len; 357 358 if (strlen(arg) > MAX_ARGSTR_LEN) { 359 pr_info("Argument is too long.: %s\n", arg); 360 return -ENOSPC; 361 } 362 parg->comm = kstrdup(arg, GFP_KERNEL); 363 if (!parg->comm) { 364 pr_info("Failed to allocate memory for command '%s'.\n", arg); 365 return -ENOMEM; 366 } 367 t = strchr(arg, ':'); 368 if (t) { 369 *t = '\0'; 370 t2 = strchr(++t, '['); 371 if (t2) { 372 *t2 = '\0'; 373 parg->count = simple_strtoul(t2 + 1, &t2, 0); 374 if (strcmp(t2, "]") || parg->count == 0) 375 return -EINVAL; 376 if (parg->count > MAX_ARRAY_LEN) 377 return -E2BIG; 378 } 379 } 380 /* 381 * The default type of $comm should be "string", and it can't be 382 * dereferenced. 383 */ 384 if (!t && strcmp(arg, "$comm") == 0) 385 parg->type = find_fetch_type("string"); 386 else 387 parg->type = find_fetch_type(t); 388 if (!parg->type) { 389 pr_info("Unsupported type: %s\n", t); 390 return -EINVAL; 391 } 392 parg->offset = *size; 393 *size += parg->type->size * (parg->count ?: 1); 394 395 if (parg->count) { 396 len = strlen(parg->type->fmttype) + 6; 397 parg->fmt = kmalloc(len, GFP_KERNEL); 398 if (!parg->fmt) 399 return -ENOMEM; 400 snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype, 401 parg->count); 402 } 403 404 code = tmp = kzalloc(sizeof(*code) * FETCH_INSN_MAX, GFP_KERNEL); 405 if (!code) 406 return -ENOMEM; 407 code[FETCH_INSN_MAX - 1].op = FETCH_OP_END; 408 409 ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1], 410 flags); 411 if (ret) 412 goto fail; 413 414 /* Store operation */ 415 if (!strcmp(parg->type->name, "string")) { 416 if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_IMM && 417 code->op != FETCH_OP_COMM) { 418 pr_info("string only accepts memory or address.\n"); 419 ret = -EINVAL; 420 goto fail; 421 } 422 if (code->op != FETCH_OP_DEREF || parg->count) { 423 /* 424 * IMM and COMM is pointing actual address, those must 425 * be kept, and if parg->count != 0, this is an array 426 * of string pointers instead of string address itself. 427 */ 428 code++; 429 if (code->op != FETCH_OP_NOP) { 430 ret = -E2BIG; 431 goto fail; 432 } 433 } 434 code->op = FETCH_OP_ST_STRING; /* In DEREF case, replace it */ 435 code->size = parg->type->size; 436 parg->dynamic = true; 437 } else if (code->op == FETCH_OP_DEREF) { 438 code->op = FETCH_OP_ST_MEM; 439 code->size = parg->type->size; 440 } else { 441 code++; 442 if (code->op != FETCH_OP_NOP) { 443 ret = -E2BIG; 444 goto fail; 445 } 446 code->op = FETCH_OP_ST_RAW; 447 code->size = parg->type->size; 448 } 449 scode = code; 450 /* Modify operation */ 451 if (t != NULL) { 452 ret = __parse_bitfield_probe_arg(t, parg->type, &code); 453 if (ret) 454 goto fail; 455 } 456 /* Loop(Array) operation */ 457 if (parg->count) { 458 if (scode->op != FETCH_OP_ST_MEM && 459 scode->op != FETCH_OP_ST_STRING) { 460 pr_info("array only accepts memory or address\n"); 461 ret = -EINVAL; 462 goto fail; 463 } 464 code++; 465 if (code->op != FETCH_OP_NOP) { 466 ret = -E2BIG; 467 goto fail; 468 } 469 code->op = FETCH_OP_LP_ARRAY; 470 code->param = parg->count; 471 } 472 code++; 473 code->op = FETCH_OP_END; 474 475 /* Shrink down the code buffer */ 476 parg->code = kzalloc(sizeof(*code) * (code - tmp + 1), GFP_KERNEL); 477 if (!parg->code) 478 ret = -ENOMEM; 479 else 480 memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1)); 481 482 fail: 483 if (ret) { 484 for (code = tmp; code < tmp + FETCH_INSN_MAX; code++) 485 if (code->op == FETCH_NOP_SYMBOL) 486 kfree(code->data); 487 } 488 kfree(tmp); 489 490 return ret; 491 } 492 493 /* Return 1 if name is reserved or already used by another argument */ 494 int traceprobe_conflict_field_name(const char *name, 495 struct probe_arg *args, int narg) 496 { 497 int i; 498 499 for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++) 500 if (strcmp(reserved_field_names[i], name) == 0) 501 return 1; 502 503 for (i = 0; i < narg; i++) 504 if (strcmp(args[i].name, name) == 0) 505 return 1; 506 507 return 0; 508 } 509 510 void traceprobe_free_probe_arg(struct probe_arg *arg) 511 { 512 struct fetch_insn *code = arg->code; 513 514 while (code && code->op != FETCH_OP_END) { 515 if (code->op == FETCH_NOP_SYMBOL) 516 kfree(code->data); 517 code++; 518 } 519 kfree(arg->code); 520 kfree(arg->name); 521 kfree(arg->comm); 522 kfree(arg->fmt); 523 } 524 525 int traceprobe_update_arg(struct probe_arg *arg) 526 { 527 struct fetch_insn *code = arg->code; 528 long offset; 529 char *tmp; 530 char c; 531 int ret = 0; 532 533 while (code && code->op != FETCH_OP_END) { 534 if (code->op == FETCH_NOP_SYMBOL) { 535 if (code[1].op != FETCH_OP_IMM) 536 return -EINVAL; 537 538 tmp = strpbrk("+-", code->data); 539 if (tmp) 540 c = *tmp; 541 ret = traceprobe_split_symbol_offset(code->data, 542 &offset); 543 if (ret) 544 return ret; 545 546 code[1].immediate = 547 (unsigned long)kallsyms_lookup_name(code->data); 548 if (tmp) 549 *tmp = c; 550 if (!code[1].immediate) 551 return -ENOENT; 552 code[1].immediate += offset; 553 } 554 code++; 555 } 556 return 0; 557 } 558 559 /* When len=0, we just calculate the needed length */ 560 #define LEN_OR_ZERO (len ? len - pos : 0) 561 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len, 562 bool is_return) 563 { 564 struct probe_arg *parg; 565 int i, j; 566 int pos = 0; 567 const char *fmt, *arg; 568 569 if (!is_return) { 570 fmt = "(%lx)"; 571 arg = "REC->" FIELD_STRING_IP; 572 } else { 573 fmt = "(%lx <- %lx)"; 574 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP; 575 } 576 577 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt); 578 579 for (i = 0; i < tp->nr_args; i++) { 580 parg = tp->args + i; 581 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name); 582 if (parg->count) { 583 pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s", 584 parg->type->fmt); 585 for (j = 1; j < parg->count; j++) 586 pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s", 587 parg->type->fmt); 588 pos += snprintf(buf + pos, LEN_OR_ZERO, "}"); 589 } else 590 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s", 591 parg->type->fmt); 592 } 593 594 pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg); 595 596 for (i = 0; i < tp->nr_args; i++) { 597 parg = tp->args + i; 598 if (parg->count) { 599 if (strcmp(parg->type->name, "string") == 0) 600 fmt = ", __get_str(%s[%d])"; 601 else 602 fmt = ", REC->%s[%d]"; 603 for (j = 0; j < parg->count; j++) 604 pos += snprintf(buf + pos, LEN_OR_ZERO, 605 fmt, parg->name, j); 606 } else { 607 if (strcmp(parg->type->name, "string") == 0) 608 fmt = ", __get_str(%s)"; 609 else 610 fmt = ", REC->%s"; 611 pos += snprintf(buf + pos, LEN_OR_ZERO, 612 fmt, parg->name); 613 } 614 } 615 616 /* return the length of print_fmt */ 617 return pos; 618 } 619 #undef LEN_OR_ZERO 620 621 int traceprobe_set_print_fmt(struct trace_probe *tp, bool is_return) 622 { 623 int len; 624 char *print_fmt; 625 626 /* First: called with 0 length to calculate the needed length */ 627 len = __set_print_fmt(tp, NULL, 0, is_return); 628 print_fmt = kmalloc(len + 1, GFP_KERNEL); 629 if (!print_fmt) 630 return -ENOMEM; 631 632 /* Second: actually write the @print_fmt */ 633 __set_print_fmt(tp, print_fmt, len + 1, is_return); 634 tp->call.print_fmt = print_fmt; 635 636 return 0; 637 } 638 639 int traceprobe_define_arg_fields(struct trace_event_call *event_call, 640 size_t offset, struct trace_probe *tp) 641 { 642 int ret, i; 643 644 /* Set argument names as fields */ 645 for (i = 0; i < tp->nr_args; i++) { 646 struct probe_arg *parg = &tp->args[i]; 647 const char *fmt = parg->type->fmttype; 648 int size = parg->type->size; 649 650 if (parg->fmt) 651 fmt = parg->fmt; 652 if (parg->count) 653 size *= parg->count; 654 ret = trace_define_field(event_call, fmt, parg->name, 655 offset + parg->offset, size, 656 parg->type->is_signed, 657 FILTER_OTHER); 658 if (ret) 659 return ret; 660 } 661 return 0; 662 } 663