1 /* Generate assembler source containing symbol information 2 * 3 * Copyright 2002 by Kai Germaschewski 4 * 5 * This software may be used and distributed according to the terms 6 * of the GNU General Public License, incorporated herein by reference. 7 * 8 * Usage: kallsyms [--all-symbols] [--absolute-percpu] 9 * [--base-relative] [--lto-clang] in.map > out.S 10 * 11 * Table compression uses all the unused char codes on the symbols and 12 * maps these to the most used substrings (tokens). For instance, it might 13 * map char code 0xF7 to represent "write_" and then in every symbol where 14 * "write_" appears it can be replaced by 0xF7, saving 5 bytes. 15 * The used codes themselves are also placed in the table so that the 16 * decompresion can work without "special cases". 17 * Applied to kernel symbols, this usually produces a compression ratio 18 * of about 50%. 19 * 20 */ 21 22 #include <errno.h> 23 #include <getopt.h> 24 #include <stdbool.h> 25 #include <stdio.h> 26 #include <stdlib.h> 27 #include <string.h> 28 #include <ctype.h> 29 #include <limits.h> 30 31 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof(arr[0])) 32 33 #define KSYM_NAME_LEN 512 34 35 struct sym_entry { 36 unsigned long long addr; 37 unsigned int len; 38 unsigned int seq; 39 unsigned int start_pos; 40 unsigned int percpu_absolute; 41 unsigned char sym[]; 42 }; 43 44 struct addr_range { 45 const char *start_sym, *end_sym; 46 unsigned long long start, end; 47 }; 48 49 static unsigned long long _text; 50 static unsigned long long relative_base; 51 static struct addr_range text_ranges[] = { 52 { "_stext", "_etext" }, 53 { "_sinittext", "_einittext" }, 54 }; 55 #define text_range_text (&text_ranges[0]) 56 #define text_range_inittext (&text_ranges[1]) 57 58 static struct addr_range percpu_range = { 59 "__per_cpu_start", "__per_cpu_end", -1ULL, 0 60 }; 61 62 static struct sym_entry **table; 63 static unsigned int table_size, table_cnt; 64 static int all_symbols; 65 static int absolute_percpu; 66 static int base_relative; 67 static int lto_clang; 68 69 static int token_profit[0x10000]; 70 71 /* the table that holds the result of the compression */ 72 static unsigned char best_table[256][2]; 73 static unsigned char best_table_len[256]; 74 75 usage(void)76 static void usage(void) 77 { 78 fprintf(stderr, "Usage: kallsyms [--all-symbols] [--absolute-percpu] " 79 "[--base-relative] [--lto-clang] in.map > out.S\n"); 80 exit(1); 81 } 82 sym_name(const struct sym_entry * s)83 static char *sym_name(const struct sym_entry *s) 84 { 85 return (char *)s->sym + 1; 86 } 87 is_ignored_symbol(const char * name,char type)88 static bool is_ignored_symbol(const char *name, char type) 89 { 90 if (type == 'u' || type == 'n') 91 return true; 92 93 if (toupper(type) == 'A') { 94 /* Keep these useful absolute symbols */ 95 if (strcmp(name, "__kernel_syscall_via_break") && 96 strcmp(name, "__kernel_syscall_via_epc") && 97 strcmp(name, "__kernel_sigtramp") && 98 strcmp(name, "__gp")) 99 return true; 100 } 101 102 return false; 103 } 104 check_symbol_range(const char * sym,unsigned long long addr,struct addr_range * ranges,int entries)105 static void check_symbol_range(const char *sym, unsigned long long addr, 106 struct addr_range *ranges, int entries) 107 { 108 size_t i; 109 struct addr_range *ar; 110 111 for (i = 0; i < entries; ++i) { 112 ar = &ranges[i]; 113 114 if (strcmp(sym, ar->start_sym) == 0) { 115 ar->start = addr; 116 return; 117 } else if (strcmp(sym, ar->end_sym) == 0) { 118 ar->end = addr; 119 return; 120 } 121 } 122 } 123 read_symbol(FILE * in,char ** buf,size_t * buf_len)124 static struct sym_entry *read_symbol(FILE *in, char **buf, size_t *buf_len) 125 { 126 char *name, type, *p; 127 unsigned long long addr; 128 size_t len; 129 ssize_t readlen; 130 struct sym_entry *sym; 131 132 errno = 0; 133 readlen = getline(buf, buf_len, in); 134 if (readlen < 0) { 135 if (errno) { 136 perror("read_symbol"); 137 exit(EXIT_FAILURE); 138 } 139 return NULL; 140 } 141 142 if ((*buf)[readlen - 1] == '\n') 143 (*buf)[readlen - 1] = 0; 144 145 addr = strtoull(*buf, &p, 16); 146 147 if (*buf == p || *p++ != ' ' || !isascii((type = *p++)) || *p++ != ' ') { 148 fprintf(stderr, "line format error\n"); 149 exit(EXIT_FAILURE); 150 } 151 152 name = p; 153 len = strlen(name); 154 155 if (len >= KSYM_NAME_LEN) { 156 fprintf(stderr, "Symbol %s too long for kallsyms (%zu >= %d).\n" 157 "Please increase KSYM_NAME_LEN both in kernel and kallsyms.c\n", 158 name, len, KSYM_NAME_LEN); 159 return NULL; 160 } 161 162 if (strcmp(name, "_text") == 0) 163 _text = addr; 164 165 /* Ignore most absolute/undefined (?) symbols. */ 166 if (is_ignored_symbol(name, type)) 167 return NULL; 168 169 check_symbol_range(name, addr, text_ranges, ARRAY_SIZE(text_ranges)); 170 check_symbol_range(name, addr, &percpu_range, 1); 171 172 /* include the type field in the symbol name, so that it gets 173 * compressed together */ 174 len++; 175 176 sym = malloc(sizeof(*sym) + len + 1); 177 if (!sym) { 178 fprintf(stderr, "kallsyms failure: " 179 "unable to allocate required amount of memory\n"); 180 exit(EXIT_FAILURE); 181 } 182 sym->addr = addr; 183 sym->len = len; 184 sym->sym[0] = type; 185 strcpy(sym_name(sym), name); 186 sym->percpu_absolute = 0; 187 188 return sym; 189 } 190 symbol_in_range(const struct sym_entry * s,const struct addr_range * ranges,int entries)191 static int symbol_in_range(const struct sym_entry *s, 192 const struct addr_range *ranges, int entries) 193 { 194 size_t i; 195 const struct addr_range *ar; 196 197 for (i = 0; i < entries; ++i) { 198 ar = &ranges[i]; 199 200 if (s->addr >= ar->start && s->addr <= ar->end) 201 return 1; 202 } 203 204 return 0; 205 } 206 symbol_valid(const struct sym_entry * s)207 static int symbol_valid(const struct sym_entry *s) 208 { 209 const char *name = sym_name(s); 210 211 /* if --all-symbols is not specified, then symbols outside the text 212 * and inittext sections are discarded */ 213 if (!all_symbols) { 214 if (symbol_in_range(s, text_ranges, 215 ARRAY_SIZE(text_ranges)) == 0) 216 return 0; 217 /* Corner case. Discard any symbols with the same value as 218 * _etext _einittext; they can move between pass 1 and 2 when 219 * the kallsyms data are added. If these symbols move then 220 * they may get dropped in pass 2, which breaks the kallsyms 221 * rules. 222 */ 223 if ((s->addr == text_range_text->end && 224 strcmp(name, text_range_text->end_sym)) || 225 (s->addr == text_range_inittext->end && 226 strcmp(name, text_range_inittext->end_sym))) 227 return 0; 228 } 229 230 return 1; 231 } 232 233 /* remove all the invalid symbols from the table */ shrink_table(void)234 static void shrink_table(void) 235 { 236 unsigned int i, pos; 237 238 pos = 0; 239 for (i = 0; i < table_cnt; i++) { 240 if (symbol_valid(table[i])) { 241 if (pos != i) 242 table[pos] = table[i]; 243 pos++; 244 } else { 245 free(table[i]); 246 } 247 } 248 table_cnt = pos; 249 250 /* When valid symbol is not registered, exit to error */ 251 if (!table_cnt) { 252 fprintf(stderr, "No valid symbol.\n"); 253 exit(1); 254 } 255 } 256 read_map(const char * in)257 static void read_map(const char *in) 258 { 259 FILE *fp; 260 struct sym_entry *sym; 261 char *buf = NULL; 262 size_t buflen = 0; 263 264 fp = fopen(in, "r"); 265 if (!fp) { 266 perror(in); 267 exit(1); 268 } 269 270 while (!feof(fp)) { 271 sym = read_symbol(fp, &buf, &buflen); 272 if (!sym) 273 continue; 274 275 sym->start_pos = table_cnt; 276 277 if (table_cnt >= table_size) { 278 table_size += 10000; 279 table = realloc(table, sizeof(*table) * table_size); 280 if (!table) { 281 fprintf(stderr, "out of memory\n"); 282 fclose(fp); 283 exit (1); 284 } 285 } 286 287 table[table_cnt++] = sym; 288 } 289 290 free(buf); 291 fclose(fp); 292 } 293 output_label(const char * label)294 static void output_label(const char *label) 295 { 296 printf(".globl %s\n", label); 297 printf("\tALGN\n"); 298 printf("%s:\n", label); 299 } 300 301 /* Provide proper symbols relocatability by their '_text' relativeness. */ output_address(unsigned long long addr)302 static void output_address(unsigned long long addr) 303 { 304 if (_text <= addr) 305 printf("\tPTR\t_text + %#llx\n", addr - _text); 306 else 307 printf("\tPTR\t_text - %#llx\n", _text - addr); 308 } 309 310 /* uncompress a compressed symbol. When this function is called, the best table 311 * might still be compressed itself, so the function needs to be recursive */ expand_symbol(const unsigned char * data,int len,char * result)312 static int expand_symbol(const unsigned char *data, int len, char *result) 313 { 314 int c, rlen, total=0; 315 316 while (len) { 317 c = *data; 318 /* if the table holds a single char that is the same as the one 319 * we are looking for, then end the search */ 320 if (best_table[c][0]==c && best_table_len[c]==1) { 321 *result++ = c; 322 total++; 323 } else { 324 /* if not, recurse and expand */ 325 rlen = expand_symbol(best_table[c], best_table_len[c], result); 326 total += rlen; 327 result += rlen; 328 } 329 data++; 330 len--; 331 } 332 *result=0; 333 334 return total; 335 } 336 symbol_absolute(const struct sym_entry * s)337 static int symbol_absolute(const struct sym_entry *s) 338 { 339 return s->percpu_absolute; 340 } 341 cleanup_symbol_name(char * s)342 static void cleanup_symbol_name(char *s) 343 { 344 char *p; 345 346 /* 347 * ASCII[.] = 2e 348 * ASCII[0-9] = 30,39 349 * ASCII[A-Z] = 41,5a 350 * ASCII[_] = 5f 351 * ASCII[a-z] = 61,7a 352 * 353 * As above, replacing the first '.' in ".llvm." with '\0' does not 354 * affect the main sorting, but it helps us with subsorting. 355 */ 356 p = strstr(s, ".llvm."); 357 if (p) 358 *p = '\0'; 359 } 360 compare_names(const void * a,const void * b)361 static int compare_names(const void *a, const void *b) 362 { 363 int ret; 364 const struct sym_entry *sa = *(const struct sym_entry **)a; 365 const struct sym_entry *sb = *(const struct sym_entry **)b; 366 367 ret = strcmp(sym_name(sa), sym_name(sb)); 368 if (!ret) { 369 if (sa->addr > sb->addr) 370 return 1; 371 else if (sa->addr < sb->addr) 372 return -1; 373 374 /* keep old order */ 375 return (int)(sa->seq - sb->seq); 376 } 377 378 return ret; 379 } 380 sort_symbols_by_name(void)381 static void sort_symbols_by_name(void) 382 { 383 qsort(table, table_cnt, sizeof(table[0]), compare_names); 384 } 385 write_src(void)386 static void write_src(void) 387 { 388 unsigned int i, k, off; 389 unsigned int best_idx[256]; 390 unsigned int *markers; 391 char buf[KSYM_NAME_LEN]; 392 393 printf("#include <asm/bitsperlong.h>\n"); 394 printf("#if BITS_PER_LONG == 64\n"); 395 printf("#define PTR .quad\n"); 396 printf("#define ALGN .balign 8\n"); 397 printf("#else\n"); 398 printf("#define PTR .long\n"); 399 printf("#define ALGN .balign 4\n"); 400 printf("#endif\n"); 401 402 printf("\t.section .rodata, \"a\"\n"); 403 404 output_label("kallsyms_num_syms"); 405 printf("\t.long\t%u\n", table_cnt); 406 printf("\n"); 407 408 /* table of offset markers, that give the offset in the compressed stream 409 * every 256 symbols */ 410 markers = malloc(sizeof(unsigned int) * ((table_cnt + 255) / 256)); 411 if (!markers) { 412 fprintf(stderr, "kallsyms failure: " 413 "unable to allocate required memory\n"); 414 exit(EXIT_FAILURE); 415 } 416 417 output_label("kallsyms_names"); 418 off = 0; 419 for (i = 0; i < table_cnt; i++) { 420 if ((i & 0xFF) == 0) 421 markers[i >> 8] = off; 422 table[i]->seq = i; 423 424 /* There cannot be any symbol of length zero. */ 425 if (table[i]->len == 0) { 426 fprintf(stderr, "kallsyms failure: " 427 "unexpected zero symbol length\n"); 428 exit(EXIT_FAILURE); 429 } 430 431 /* Only lengths that fit in up-to-two-byte ULEB128 are supported. */ 432 if (table[i]->len > 0x3FFF) { 433 fprintf(stderr, "kallsyms failure: " 434 "unexpected huge symbol length\n"); 435 exit(EXIT_FAILURE); 436 } 437 438 /* Encode length with ULEB128. */ 439 if (table[i]->len <= 0x7F) { 440 /* Most symbols use a single byte for the length. */ 441 printf("\t.byte 0x%02x", table[i]->len); 442 off += table[i]->len + 1; 443 } else { 444 /* "Big" symbols use two bytes. */ 445 printf("\t.byte 0x%02x, 0x%02x", 446 (table[i]->len & 0x7F) | 0x80, 447 (table[i]->len >> 7) & 0x7F); 448 off += table[i]->len + 2; 449 } 450 for (k = 0; k < table[i]->len; k++) 451 printf(", 0x%02x", table[i]->sym[k]); 452 printf("\n"); 453 } 454 printf("\n"); 455 456 /* 457 * Now that we wrote out the compressed symbol names, restore the 458 * original names, which are needed in some of the later steps. 459 */ 460 for (i = 0; i < table_cnt; i++) { 461 expand_symbol(table[i]->sym, table[i]->len, buf); 462 strcpy((char *)table[i]->sym, buf); 463 } 464 465 output_label("kallsyms_markers"); 466 for (i = 0; i < ((table_cnt + 255) >> 8); i++) 467 printf("\t.long\t%u\n", markers[i]); 468 printf("\n"); 469 470 free(markers); 471 472 output_label("kallsyms_token_table"); 473 off = 0; 474 for (i = 0; i < 256; i++) { 475 best_idx[i] = off; 476 expand_symbol(best_table[i], best_table_len[i], buf); 477 printf("\t.asciz\t\"%s\"\n", buf); 478 off += strlen(buf) + 1; 479 } 480 printf("\n"); 481 482 output_label("kallsyms_token_index"); 483 for (i = 0; i < 256; i++) 484 printf("\t.short\t%d\n", best_idx[i]); 485 printf("\n"); 486 487 if (!base_relative) 488 output_label("kallsyms_addresses"); 489 else 490 output_label("kallsyms_offsets"); 491 492 for (i = 0; i < table_cnt; i++) { 493 if (base_relative) { 494 /* 495 * Use the offset relative to the lowest value 496 * encountered of all relative symbols, and emit 497 * non-relocatable fixed offsets that will be fixed 498 * up at runtime. 499 */ 500 501 long long offset; 502 int overflow; 503 504 if (!absolute_percpu) { 505 offset = table[i]->addr - relative_base; 506 overflow = (offset < 0 || offset > UINT_MAX); 507 } else if (symbol_absolute(table[i])) { 508 offset = table[i]->addr; 509 overflow = (offset < 0 || offset > INT_MAX); 510 } else { 511 offset = relative_base - table[i]->addr - 1; 512 overflow = (offset < INT_MIN || offset >= 0); 513 } 514 if (overflow) { 515 fprintf(stderr, "kallsyms failure: " 516 "%s symbol value %#llx out of range in relative mode\n", 517 symbol_absolute(table[i]) ? "absolute" : "relative", 518 table[i]->addr); 519 exit(EXIT_FAILURE); 520 } 521 printf("\t.long\t%#x /* %s */\n", (int)offset, table[i]->sym); 522 } else if (!symbol_absolute(table[i])) { 523 output_address(table[i]->addr); 524 } else { 525 printf("\tPTR\t%#llx\n", table[i]->addr); 526 } 527 } 528 printf("\n"); 529 530 if (base_relative) { 531 output_label("kallsyms_relative_base"); 532 output_address(relative_base); 533 printf("\n"); 534 } 535 536 if (lto_clang) 537 for (i = 0; i < table_cnt; i++) 538 cleanup_symbol_name((char *)table[i]->sym); 539 540 sort_symbols_by_name(); 541 output_label("kallsyms_seqs_of_names"); 542 for (i = 0; i < table_cnt; i++) 543 printf("\t.byte 0x%02x, 0x%02x, 0x%02x\n", 544 (unsigned char)(table[i]->seq >> 16), 545 (unsigned char)(table[i]->seq >> 8), 546 (unsigned char)(table[i]->seq >> 0)); 547 printf("\n"); 548 } 549 550 551 /* table lookup compression functions */ 552 553 /* count all the possible tokens in a symbol */ learn_symbol(const unsigned char * symbol,int len)554 static void learn_symbol(const unsigned char *symbol, int len) 555 { 556 int i; 557 558 for (i = 0; i < len - 1; i++) 559 token_profit[ symbol[i] + (symbol[i + 1] << 8) ]++; 560 } 561 562 /* decrease the count for all the possible tokens in a symbol */ forget_symbol(const unsigned char * symbol,int len)563 static void forget_symbol(const unsigned char *symbol, int len) 564 { 565 int i; 566 567 for (i = 0; i < len - 1; i++) 568 token_profit[ symbol[i] + (symbol[i + 1] << 8) ]--; 569 } 570 571 /* do the initial token count */ build_initial_token_table(void)572 static void build_initial_token_table(void) 573 { 574 unsigned int i; 575 576 for (i = 0; i < table_cnt; i++) 577 learn_symbol(table[i]->sym, table[i]->len); 578 } 579 find_token(unsigned char * str,int len,const unsigned char * token)580 static unsigned char *find_token(unsigned char *str, int len, 581 const unsigned char *token) 582 { 583 int i; 584 585 for (i = 0; i < len - 1; i++) { 586 if (str[i] == token[0] && str[i+1] == token[1]) 587 return &str[i]; 588 } 589 return NULL; 590 } 591 592 /* replace a given token in all the valid symbols. Use the sampled symbols 593 * to update the counts */ compress_symbols(const unsigned char * str,int idx)594 static void compress_symbols(const unsigned char *str, int idx) 595 { 596 unsigned int i, len, size; 597 unsigned char *p1, *p2; 598 599 for (i = 0; i < table_cnt; i++) { 600 601 len = table[i]->len; 602 p1 = table[i]->sym; 603 604 /* find the token on the symbol */ 605 p2 = find_token(p1, len, str); 606 if (!p2) continue; 607 608 /* decrease the counts for this symbol's tokens */ 609 forget_symbol(table[i]->sym, len); 610 611 size = len; 612 613 do { 614 *p2 = idx; 615 p2++; 616 size -= (p2 - p1); 617 memmove(p2, p2 + 1, size); 618 p1 = p2; 619 len--; 620 621 if (size < 2) break; 622 623 /* find the token on the symbol */ 624 p2 = find_token(p1, size, str); 625 626 } while (p2); 627 628 table[i]->len = len; 629 630 /* increase the counts for this symbol's new tokens */ 631 learn_symbol(table[i]->sym, len); 632 } 633 } 634 635 /* search the token with the maximum profit */ find_best_token(void)636 static int find_best_token(void) 637 { 638 int i, best, bestprofit; 639 640 bestprofit=-10000; 641 best = 0; 642 643 for (i = 0; i < 0x10000; i++) { 644 if (token_profit[i] > bestprofit) { 645 best = i; 646 bestprofit = token_profit[i]; 647 } 648 } 649 return best; 650 } 651 652 /* this is the core of the algorithm: calculate the "best" table */ optimize_result(void)653 static void optimize_result(void) 654 { 655 int i, best; 656 657 /* using the '\0' symbol last allows compress_symbols to use standard 658 * fast string functions */ 659 for (i = 255; i >= 0; i--) { 660 661 /* if this table slot is empty (it is not used by an actual 662 * original char code */ 663 if (!best_table_len[i]) { 664 665 /* find the token with the best profit value */ 666 best = find_best_token(); 667 if (token_profit[best] == 0) 668 break; 669 670 /* place it in the "best" table */ 671 best_table_len[i] = 2; 672 best_table[i][0] = best & 0xFF; 673 best_table[i][1] = (best >> 8) & 0xFF; 674 675 /* replace this token in all the valid symbols */ 676 compress_symbols(best_table[i], i); 677 } 678 } 679 } 680 681 /* start by placing the symbols that are actually used on the table */ insert_real_symbols_in_table(void)682 static void insert_real_symbols_in_table(void) 683 { 684 unsigned int i, j, c; 685 686 for (i = 0; i < table_cnt; i++) { 687 for (j = 0; j < table[i]->len; j++) { 688 c = table[i]->sym[j]; 689 best_table[c][0]=c; 690 best_table_len[c]=1; 691 } 692 } 693 } 694 optimize_token_table(void)695 static void optimize_token_table(void) 696 { 697 build_initial_token_table(); 698 699 insert_real_symbols_in_table(); 700 701 optimize_result(); 702 } 703 704 /* guess for "linker script provide" symbol */ may_be_linker_script_provide_symbol(const struct sym_entry * se)705 static int may_be_linker_script_provide_symbol(const struct sym_entry *se) 706 { 707 const char *symbol = sym_name(se); 708 int len = se->len - 1; 709 710 if (len < 8) 711 return 0; 712 713 if (symbol[0] != '_' || symbol[1] != '_') 714 return 0; 715 716 /* __start_XXXXX */ 717 if (!memcmp(symbol + 2, "start_", 6)) 718 return 1; 719 720 /* __stop_XXXXX */ 721 if (!memcmp(symbol + 2, "stop_", 5)) 722 return 1; 723 724 /* __end_XXXXX */ 725 if (!memcmp(symbol + 2, "end_", 4)) 726 return 1; 727 728 /* __XXXXX_start */ 729 if (!memcmp(symbol + len - 6, "_start", 6)) 730 return 1; 731 732 /* __XXXXX_end */ 733 if (!memcmp(symbol + len - 4, "_end", 4)) 734 return 1; 735 736 return 0; 737 } 738 compare_symbols(const void * a,const void * b)739 static int compare_symbols(const void *a, const void *b) 740 { 741 const struct sym_entry *sa = *(const struct sym_entry **)a; 742 const struct sym_entry *sb = *(const struct sym_entry **)b; 743 int wa, wb; 744 745 /* sort by address first */ 746 if (sa->addr > sb->addr) 747 return 1; 748 if (sa->addr < sb->addr) 749 return -1; 750 751 /* sort by "weakness" type */ 752 wa = (sa->sym[0] == 'w') || (sa->sym[0] == 'W'); 753 wb = (sb->sym[0] == 'w') || (sb->sym[0] == 'W'); 754 if (wa != wb) 755 return wa - wb; 756 757 /* sort by "linker script provide" type */ 758 wa = may_be_linker_script_provide_symbol(sa); 759 wb = may_be_linker_script_provide_symbol(sb); 760 if (wa != wb) 761 return wa - wb; 762 763 /* sort by the number of prefix underscores */ 764 wa = strspn(sym_name(sa), "_"); 765 wb = strspn(sym_name(sb), "_"); 766 if (wa != wb) 767 return wa - wb; 768 769 /* sort by initial order, so that other symbols are left undisturbed */ 770 return sa->start_pos - sb->start_pos; 771 } 772 sort_symbols(void)773 static void sort_symbols(void) 774 { 775 qsort(table, table_cnt, sizeof(table[0]), compare_symbols); 776 } 777 make_percpus_absolute(void)778 static void make_percpus_absolute(void) 779 { 780 unsigned int i; 781 782 for (i = 0; i < table_cnt; i++) 783 if (symbol_in_range(table[i], &percpu_range, 1)) { 784 /* 785 * Keep the 'A' override for percpu symbols to 786 * ensure consistent behavior compared to older 787 * versions of this tool. 788 */ 789 table[i]->sym[0] = 'A'; 790 table[i]->percpu_absolute = 1; 791 } 792 } 793 794 /* find the minimum non-absolute symbol address */ record_relative_base(void)795 static void record_relative_base(void) 796 { 797 unsigned int i; 798 799 for (i = 0; i < table_cnt; i++) 800 if (!symbol_absolute(table[i])) { 801 /* 802 * The table is sorted by address. 803 * Take the first non-absolute symbol value. 804 */ 805 relative_base = table[i]->addr; 806 return; 807 } 808 } 809 main(int argc,char ** argv)810 int main(int argc, char **argv) 811 { 812 while (1) { 813 static const struct option long_options[] = { 814 {"all-symbols", no_argument, &all_symbols, 1}, 815 {"absolute-percpu", no_argument, &absolute_percpu, 1}, 816 {"base-relative", no_argument, &base_relative, 1}, 817 {"lto-clang", no_argument, <o_clang, 1}, 818 {}, 819 }; 820 821 int c = getopt_long(argc, argv, "", long_options, NULL); 822 823 if (c == -1) 824 break; 825 if (c != 0) 826 usage(); 827 } 828 829 if (optind >= argc) 830 usage(); 831 832 read_map(argv[optind]); 833 shrink_table(); 834 if (absolute_percpu) 835 make_percpus_absolute(); 836 sort_symbols(); 837 if (base_relative) 838 record_relative_base(); 839 optimize_token_table(); 840 write_src(); 841 842 return 0; 843 } 844