scripts/kallsyms.c

   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: nm -n vmlinux | scripts/kallsyms [--all-symbols] > symbols.S
   9  *
  10  *      Table compression uses all the unused char codes on the symbols and
  11  *  maps these to the most used substrings (tokens). For instance, it might
  12  *  map char code 0xF7 to represent "write_" and then in every symbol where
  13  *  "write_" appears it can be replaced by 0xF7, saving 5 bytes.
  14  *      The used codes themselves are also placed in the table so that the
  15  *  decompresion can work without "special cases".
  16  *      Applied to kernel symbols, this usually produces a compression ratio
  17  *  of about 50%.
  18  *
  19  */
  20
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <ctype.h>
  25 #include <limits.h>
  26
  27 #ifndef ARRAY_SIZE
  28 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof(arr[0]))
  29 #endif
  30
  31 #define KSYM_NAME_LEN           128
  32
  33 struct sym_entry {
  34         unsigned long long addr;
  35         unsigned int len;
  36         unsigned int start_pos;
  37         unsigned char *sym;
  38         unsigned int percpu_absolute;
  39 };
  40
  41 struct addr_range {
  42         const char *start_sym, *end_sym;
  43         unsigned long long start, end;
  44 };
  45
  46 static unsigned long long _text;
  47 static unsigned long long relative_base;
  48 static struct addr_range text_ranges[] = {
  49         { "_stext",     "_etext"     },
  50         { "_sinittext", "_einittext" },
  51         { "_stext_l1",  "_etext_l1"  }, /* Blackfin on-chip L1 inst SRAM */
  52         { "_stext_l2",  "_etext_l2"  }, /* Blackfin on-chip L2 SRAM */
  53 };
  54 #define text_range_text     (&text_ranges[0])
  55 #define text_range_inittext (&text_ranges[1])
  56
  57 static struct addr_range percpu_range = {
  58         "__per_cpu_start", "__per_cpu_end", -1ULL, 0
  59 };
  60
  61 static struct sym_entry *table;
  62 static unsigned int table_size, table_cnt;
  63 static int all_symbols = 0;
  64 static int absolute_percpu = 0;
  65 static char symbol_prefix_char = '\0';
  66 static int base_relative = 0;
  67
  68 int token_profit[0x10000];
  69
  70 /* the table that holds the result of the compression */
  71 unsigned char best_table[256][2];
  72 unsigned char best_table_len[256];
  73
  74
  75 static void usage(void)
  76 {
  77         fprintf(stderr, "Usage: kallsyms [--all-symbols] "
  78                         "[--symbol-prefix=<prefix char>] "
  79                         "[--base-relative] < in.map > out.S\n");
  80         exit(1);
  81 }
  82
  83 /*
  84  * This ignores the intensely annoying "mapping symbols" found
  85  * in ARM ELF files: $a, $t and $d.
  86  */
  87 static inline int is_arm_mapping_symbol(const char *str)
  88 {
  89         return str[0] == '$' && strchr("axtd", str[1])
  90                && (str[2] == '\0' || str[2] == '.');
  91 }
  92
  93 static int check_symbol_range(const char *sym, unsigned long long addr,
  94                               struct addr_range *ranges, int entries)
  95 {
  96         size_t i;
  97         struct addr_range *ar;
  98
  99         for (i = 0; i < entries; ++i) {
 100                 ar = &ranges[i];
 101
 102                 if (strcmp(sym, ar->start_sym) == 0) {
 103                         ar->start = addr;
 104                         return 0;
 105                 } else if (strcmp(sym, ar->end_sym) == 0) {
 106                         ar->end = addr;
 107                         return 0;
 108                 }
 109         }
 110
 111         return 1;
 112 }
 113
 114 static int read_symbol(FILE *in, struct sym_entry *s)
 115 {
 116         char str[500];
 117         char *sym, stype;
 118         int rc;
 119
 120         rc = fscanf(in, "%llx %c %499s\n", &s->addr, &stype, str);
 121         if (rc != 3) {
 122                 if (rc != EOF && fgets(str, 500, in) == NULL)
 123                         fprintf(stderr, "Read error or end of file.\n");
 124                 return -1;
 125         }
 126         if (strlen(str) > KSYM_NAME_LEN) {
 127                 fprintf(stderr, "Symbol %s too long for kallsyms (%zu vs %d).\n"
 128                                 "Please increase KSYM_NAME_LEN both in kernel and kallsyms.c\n",
 129                         str, strlen(str), KSYM_NAME_LEN);
 130                 return -1;
 131         }
 132
 133         sym = str;
 134         /* skip prefix char */
 135         if (symbol_prefix_char && str[0] == symbol_prefix_char)
 136                 sym++;
 137
 138         /* Ignore most absolute/undefined (?) symbols. */
 139         if (strcmp(sym, "_text") == 0)
 140                 _text = s->addr;
 141         else if (check_symbol_range(sym, s->addr, text_ranges,
 142                                     ARRAY_SIZE(text_ranges)) == 0)
 143                 /* nothing to do */;
 144         else if (toupper(stype) == 'A')
 145         {
 146                 /* Keep these useful absolute symbols */
 147                 if (strcmp(sym, "__kernel_syscall_via_break") &&
 148                     strcmp(sym, "__kernel_syscall_via_epc") &&
 149                     strcmp(sym, "__kernel_sigtramp") &&
 150                     strcmp(sym, "__gp"))
 151                         return -1;
 152
 153         }
 154         else if (toupper(stype) == 'U' ||
 155                  is_arm_mapping_symbol(sym))
 156                 return -1;
 157         /* exclude also MIPS ELF local symbols ($L123 instead of .L123) */
 158         else if (str[0] == '$')
 159                 return -1;
 160         /* exclude debugging symbols */
 161         else if (stype == 'N' || stype == 'n')
 162                 return -1;
 163         /* exclude s390 kasan local symbols */
 164         else if (!strncmp(sym, ".LASANPC", 8))
 165                 return -1;
 166
 167         /* include the type field in the symbol name, so that it gets
 168          * compressed together */
 169         s->len = strlen(str) + 1;
 170         s->sym = malloc(s->len + 1);
 171         if (!s->sym) {
 172                 fprintf(stderr, "kallsyms failure: "
 173                         "unable to allocate required amount of memory\n");
 174                 exit(EXIT_FAILURE);
 175         }
 176         strcpy((char *)s->sym + 1, str);
 177         s->sym[0] = stype;
 178
 179         s->percpu_absolute = 0;
 180
 181         /* Record if we've found __per_cpu_start/end. */
 182         check_symbol_range(sym, s->addr, &percpu_range, 1);
 183
 184         return 0;
 185 }
 186
 187 static int symbol_in_range(struct sym_entry *s, struct addr_range *ranges,
 188                            int entries)
 189 {
 190         size_t i;
 191         struct addr_range *ar;
 192
 193         for (i = 0; i < entries; ++i) {
 194                 ar = &ranges[i];
 195
 196                 if (s->addr >= ar->start && s->addr <= ar->end)
 197                         return 1;
 198         }
 199
 200         return 0;
 201 }
 202
 203 static int symbol_valid(struct sym_entry *s)
 204 {
 205         /* Symbols which vary between passes.  Passes 1 and 2 must have
 206          * identical symbol lists.  The kallsyms_* symbols below are only added
 207          * after pass 1, they would be included in pass 2 when --all-symbols is
 208          * specified so exclude them to get a stable symbol list.
 209          */
 210         static char *special_symbols[] = {
 211                 "kallsyms_addresses",
 212                 "kallsyms_offsets",
 213                 "kallsyms_relative_base",
 214                 "kallsyms_num_syms",
 215                 "kallsyms_names",
 216                 "kallsyms_markers",
 217                 "kallsyms_token_table",
 218                 "kallsyms_token_index",
 219
 220         /* Exclude linker generated symbols which vary between passes */
 221                 "_SDA_BASE_",           /* ppc */
 222                 "_SDA2_BASE_",          /* ppc */
 223                 NULL };
 224
 225         static char *special_prefixes[] = {
 226                 "__crc_",               /* modversions */
 227                 "__efistub_",           /* arm64 EFI stub namespace */
 228                 NULL };
 229
 230         static char *special_suffixes[] = {
 231                 "_veneer",              /* arm */
 232                 "_from_arm",            /* arm */
 233                 "_from_thumb",          /* arm */
 234                 NULL };
 235
 236         int i;
 237         char *sym_name = (char *)s->sym + 1;
 238
 239         /* skip prefix char */
 240         if (symbol_prefix_char && *sym_name == symbol_prefix_char)
 241                 sym_name++;
 242
 243
 244         /* if --all-symbols is not specified, then symbols outside the text
 245          * and inittext sections are discarded */
 246         if (!all_symbols) {
 247                 if (symbol_in_range(s, text_ranges,
 248                                     ARRAY_SIZE(text_ranges)) == 0)
 249                         return 0;
 250                 /* Corner case.  Discard any symbols with the same value as
 251                  * _etext _einittext; they can move between pass 1 and 2 when
 252                  * the kallsyms data are added.  If these symbols move then
 253                  * they may get dropped in pass 2, which breaks the kallsyms
 254                  * rules.
 255                  */
 256                 if ((s->addr == text_range_text->end &&
 257                                 strcmp(sym_name,
 258                                        text_range_text->end_sym)) ||
 259                     (s->addr == text_range_inittext->end &&
 260                                 strcmp(sym_name,
 261                                        text_range_inittext->end_sym)))
 262                         return 0;
 263         }
 264
 265         /* Exclude symbols which vary between passes. */
 266         for (i = 0; special_symbols[i]; i++)
 267                 if (strcmp(sym_name, special_symbols[i]) == 0)
 268                         return 0;
 269
 270         for (i = 0; special_prefixes[i]; i++) {
 271                 int l = strlen(special_prefixes[i]);
 272
 273                 if (l <= strlen(sym_name) &&
 274                     strncmp(sym_name, special_prefixes[i], l) == 0)
 275                         return 0;
 276         }
 277
 278         for (i = 0; special_suffixes[i]; i++) {
 279                 int l = strlen(sym_name) - strlen(special_suffixes[i]);
 280
 281                 if (l >= 0 && strcmp(sym_name + l, special_suffixes[i]) == 0)
 282                         return 0;
 283         }
 284
 285         return 1;
 286 }
 287
 288 static void read_map(FILE *in)
 289 {
 290         while (!feof(in)) {
 291                 if (table_cnt >= table_size) {
 292                         table_size += 10000;
 293                         table = realloc(table, sizeof(*table) * table_size);
 294                         if (!table) {
 295                                 fprintf(stderr, "out of memory\n");
 296                                 exit (1);
 297                         }
 298                 }
 299                 if (read_symbol(in, &table[table_cnt]) == 0) {
 300                         table[table_cnt].start_pos = table_cnt;
 301                         table_cnt++;
 302                 }
 303         }
 304 }
 305
 306 static void output_label(char *label)
 307 {
 308         if (symbol_prefix_char)
 309                 printf(".globl %c%s\n", symbol_prefix_char, label);
 310         else
 311                 printf(".globl %s\n", label);
 312         printf("\tALGN\n");
 313         if (symbol_prefix_char)
 314                 printf("%c%s:\n", symbol_prefix_char, label);
 315         else
 316                 printf("%s:\n", label);
 317 }
 318
 319 /* uncompress a compressed symbol. When this function is called, the best table
 320  * might still be compressed itself, so the function needs to be recursive */
 321 static int expand_symbol(unsigned char *data, int len, char *result)
 322 {
 323         int c, rlen, total=0;
 324
 325         while (len) {
 326                 c = *data;
 327                 /* if the table holds a single char that is the same as the one
 328                  * we are looking for, then end the search */
 329                 if (best_table[c][0]==c && best_table_len[c]==1) {
 330                         *result++ = c;
 331                         total++;
 332                 } else {
 333                         /* if not, recurse and expand */
 334                         rlen = expand_symbol(best_table[c], best_table_len[c], result);
 335                         total += rlen;
 336                         result += rlen;
 337                 }
 338                 data++;
 339                 len--;
 340         }
 341         *result=0;
 342
 343         return total;
 344 }
 345
 346 static int symbol_absolute(struct sym_entry *s)
 347 {
 348         return s->percpu_absolute;
 349 }
 350
 351 static void write_src(void)
 352 {
 353         unsigned int i, k, off;
 354         unsigned int best_idx[256];
 355         unsigned int *markers;
 356         char buf[KSYM_NAME_LEN];
 357
 358         printf("#include <asm/types.h>\n");
 359         printf("#if BITS_PER_LONG == 64\n");
 360         printf("#define PTR .quad\n");
 361         printf("#define ALGN .align 8\n");
 362         printf("#else\n");
 363         printf("#define PTR .long\n");
 364         printf("#define ALGN .align 4\n");
 365         printf("#endif\n");
 366
 367         printf("\t.section .rodata, \"a\"\n");
 368
 369         /* Provide proper symbols relocatability by their relativeness
 370          * to a fixed anchor point in the runtime image, either '_text'
 371          * for absolute address tables, in which case the linker will
 372          * emit the final addresses at build time. Otherwise, use the
 373          * offset relative to the lowest value encountered of all relative
 374          * symbols, and emit non-relocatable fixed offsets that will be fixed
 375          * up at runtime.
 376          *
 377          * The symbol names cannot be used to construct normal symbol
 378          * references as the list of symbols contains symbols that are
 379          * declared static and are private to their .o files.  This prevents
 380          * .tmp_kallsyms.o or any other object from referencing them.
 381          */
 382         if (!base_relative)
 383                 output_label("kallsyms_addresses");
 384         else
 385                 output_label("kallsyms_offsets");
 386
 387         for (i = 0; i < table_cnt; i++) {
 388                 if (base_relative) {
 389                         long long offset;
 390                         int overflow;
 391
 392                         if (!absolute_percpu) {
 393                                 offset = table[i].addr - relative_base;
 394                                 overflow = (offset < 0 || offset > UINT_MAX);
 395                         } else if (symbol_absolute(&table[i])) {
 396                                 offset = table[i].addr;
 397                                 overflow = (offset < 0 || offset > INT_MAX);
 398                         } else {
 399                                 offset = relative_base - table[i].addr - 1;
 400                                 overflow = (offset < INT_MIN || offset >= 0);
 401                         }
 402                         if (overflow) {
 403                                 fprintf(stderr, "kallsyms failure: "
 404                                         "%s symbol value %#llx out of range in relative mode\n",
 405                                         symbol_absolute(&table[i]) ? "absolute" : "relative",
 406                                         table[i].addr);
 407                                 exit(EXIT_FAILURE);
 408                         }
 409                         printf("\t.long\t%#x\n", (int)offset);
 410                 } else if (!symbol_absolute(&table[i])) {
 411                         if (_text <= table[i].addr)
 412                                 printf("\tPTR\t_text + %#llx\n",
 413                                         table[i].addr - _text);
 414                         else
 415                                 printf("\tPTR\t_text - %#llx\n",
 416                                         _text - table[i].addr);
 417                 } else {
 418                         printf("\tPTR\t%#llx\n", table[i].addr);
 419                 }
 420         }
 421         printf("\n");
 422
 423         if (base_relative) {
 424                 output_label("kallsyms_relative_base");
 425                 printf("\tPTR\t_text - %#llx\n", _text - relative_base);
 426                 printf("\n");
 427         }
 428
 429         output_label("kallsyms_num_syms");
 430         printf("\tPTR\t%d\n", table_cnt);
 431         printf("\n");
 432
 433         /* table of offset markers, that give the offset in the compressed stream
 434          * every 256 symbols */
 435         markers = malloc(sizeof(unsigned int) * ((table_cnt + 255) / 256));
 436         if (!markers) {
 437                 fprintf(stderr, "kallsyms failure: "
 438                         "unable to allocate required memory\n");
 439                 exit(EXIT_FAILURE);
 440         }
 441
 442         output_label("kallsyms_names");
 443         off = 0;
 444         for (i = 0; i < table_cnt; i++) {
 445                 if ((i & 0xFF) == 0)
 446                         markers[i >> 8] = off;
 447
 448                 printf("\t.byte 0x%02x", table[i].len);
 449                 for (k = 0; k < table[i].len; k++)
 450                         printf(", 0x%02x", table[i].sym[k]);
 451                 printf("\n");
 452
 453                 off += table[i].len + 1;
 454         }
 455         printf("\n");
 456
 457         output_label("kallsyms_markers");
 458         for (i = 0; i < ((table_cnt + 255) >> 8); i++)
 459                 printf("\tPTR\t%d\n", markers[i]);
 460         printf("\n");
 461
 462         free(markers);
 463
 464         output_label("kallsyms_token_table");
 465         off = 0;
 466         for (i = 0; i < 256; i++) {
 467                 best_idx[i] = off;
 468                 expand_symbol(best_table[i], best_table_len[i], buf);
 469                 printf("\t.asciz\t\"%s\"\n", buf);
 470                 off += strlen(buf) + 1;
 471         }
 472         printf("\n");
 473
 474         output_label("kallsyms_token_index");
 475         for (i = 0; i < 256; i++)
 476                 printf("\t.short\t%d\n", best_idx[i]);
 477         printf("\n");
 478 }
 479
 480
 481 /* table lookup compression functions */
 482
 483 /* count all the possible tokens in a symbol */
 484 static void learn_symbol(unsigned char *symbol, int len)
 485 {
 486         int i;
 487
 488         for (i = 0; i < len - 1; i++)
 489                 token_profit[ symbol[i] + (symbol[i + 1] << 8) ]++;
 490 }
 491
 492 /* decrease the count for all the possible tokens in a symbol */
 493 static void forget_symbol(unsigned char *symbol, int len)
 494 {
 495         int i;
 496
 497         for (i = 0; i < len - 1; i++)
 498                 token_profit[ symbol[i] + (symbol[i + 1] << 8) ]--;
 499 }
 500
 501 /* remove all the invalid symbols from the table and do the initial token count */
 502 static void build_initial_tok_table(void)
 503 {
 504         unsigned int i, pos;
 505
 506         pos = 0;
 507         for (i = 0; i < table_cnt; i++) {
 508                 if ( symbol_valid(&table[i]) ) {
 509                         if (pos != i)
 510                                 table[pos] = table[i];
 511                         learn_symbol(table[pos].sym, table[pos].len);
 512                         pos++;
 513                 } else {
 514                         free(table[i].sym);
 515                 }
 516         }
 517         table_cnt = pos;
 518 }
 519
 520 static void *find_token(unsigned char *str, int len, unsigned char *token)
 521 {
 522         int i;
 523
 524         for (i = 0; i < len - 1; i++) {
 525                 if (str[i] == token[0] && str[i+1] == token[1])
 526                         return &str[i];
 527         }
 528         return NULL;
 529 }
 530
 531 /* replace a given token in all the valid symbols. Use the sampled symbols
 532  * to update the counts */
 533 static void compress_symbols(unsigned char *str, int idx)
 534 {
 535         unsigned int i, len, size;
 536         unsigned char *p1, *p2;
 537
 538         for (i = 0; i < table_cnt; i++) {
 539
 540                 len = table[i].len;
 541                 p1 = table[i].sym;
 542
 543                 /* find the token on the symbol */
 544                 p2 = find_token(p1, len, str);
 545                 if (!p2) continue;
 546
 547                 /* decrease the counts for this symbol's tokens */
 548                 forget_symbol(table[i].sym, len);
 549
 550                 size = len;
 551
 552                 do {
 553                         *p2 = idx;
 554                         p2++;
 555                         size -= (p2 - p1);
 556                         memmove(p2, p2 + 1, size);
 557                         p1 = p2;
 558                         len--;
 559
 560                         if (size < 2) break;
 561
 562                         /* find the token on the symbol */
 563                         p2 = find_token(p1, size, str);
 564
 565                 } while (p2);
 566
 567                 table[i].len = len;
 568
 569                 /* increase the counts for this symbol's new tokens */
 570                 learn_symbol(table[i].sym, len);
 571         }
 572 }
 573
 574 /* search the token with the maximum profit */
 575 static int find_best_token(void)
 576 {
 577         int i, best, bestprofit;
 578
 579         bestprofit=-10000;
 580         best = 0;
 581
 582         for (i = 0; i < 0x10000; i++) {
 583                 if (token_profit[i] > bestprofit) {
 584                         best = i;
 585                         bestprofit = token_profit[i];
 586                 }
 587         }
 588         return best;
 589 }
 590
 591 /* this is the core of the algorithm: calculate the "best" table */
 592 static void optimize_result(void)
 593 {
 594         int i, best;
 595
 596         /* using the '\0' symbol last allows compress_symbols to use standard
 597          * fast string functions */
 598         for (i = 255; i >= 0; i--) {
 599
 600                 /* if this table slot is empty (it is not used by an actual
 601                  * original char code */
 602                 if (!best_table_len[i]) {
 603
 604                         /* find the token with the breates profit value */
 605                         best = find_best_token();
 606                         if (token_profit[best] == 0)
 607                                 break;
 608
 609                         /* place it in the "best" table */
 610                         best_table_len[i] = 2;
 611                         best_table[i][0] = best & 0xFF;
 612                         best_table[i][1] = (best >> 8) & 0xFF;
 613
 614                         /* replace this token in all the valid symbols */
 615                         compress_symbols(best_table[i], i);
 616                 }
 617         }
 618 }
 619
 620 /* start by placing the symbols that are actually used on the table */
 621 static void insert_real_symbols_in_table(void)
 622 {
 623         unsigned int i, j, c;
 624
 625         memset(best_table, 0, sizeof(best_table));
 626         memset(best_table_len, 0, sizeof(best_table_len));
 627
 628         for (i = 0; i < table_cnt; i++) {
 629                 for (j = 0; j < table[i].len; j++) {
 630                         c = table[i].sym[j];
 631                         best_table[c][0]=c;
 632                         best_table_len[c]=1;
 633                 }
 634         }
 635 }
 636
 637 static void optimize_token_table(void)
 638 {
 639         build_initial_tok_table();
 640
 641         insert_real_symbols_in_table();
 642
 643         /* When valid symbol is not registered, exit to error */
 644         if (!table_cnt) {
 645                 fprintf(stderr, "No valid symbol.\n");
 646                 exit(1);
 647         }
 648
 649         optimize_result();
 650 }
 651
 652 /* guess for "linker script provide" symbol */
 653 static int may_be_linker_script_provide_symbol(const struct sym_entry *se)
 654 {
 655         const char *symbol = (char *)se->sym + 1;
 656         int len = se->len - 1;
 657
 658         if (len < 8)
 659                 return 0;
 660
 661         if (symbol[0] != '_' || symbol[1] != '_')
 662                 return 0;
 663
 664         /* __start_XXXXX */
 665         if (!memcmp(symbol + 2, "start_", 6))
 666                 return 1;
 667
 668         /* __stop_XXXXX */
 669         if (!memcmp(symbol + 2, "stop_", 5))
 670                 return 1;
 671
 672         /* __end_XXXXX */
 673         if (!memcmp(symbol + 2, "end_", 4))
 674                 return 1;
 675
 676         /* __XXXXX_start */
 677         if (!memcmp(symbol + len - 6, "_start", 6))
 678                 return 1;
 679
 680         /* __XXXXX_end */
 681         if (!memcmp(symbol + len - 4, "_end", 4))
 682                 return 1;
 683
 684         return 0;
 685 }
 686
 687 static int prefix_underscores_count(const char *str)
 688 {
 689         const char *tail = str;
 690
 691         while (*tail == '_')
 692                 tail++;
 693
 694         return tail - str;
 695 }
 696
 697 static int compare_symbols(const void *a, const void *b)
 698 {
 699         const struct sym_entry *sa;
 700         const struct sym_entry *sb;
 701         int wa, wb;
 702
 703         sa = a;
 704         sb = b;
 705
 706         /* sort by address first */
 707         if (sa->addr > sb->addr)
 708                 return 1;
 709         if (sa->addr < sb->addr)
 710                 return -1;
 711
 712         /* sort by "weakness" type */
 713         wa = (sa->sym[0] == 'w') || (sa->sym[0] == 'W');
 714         wb = (sb->sym[0] == 'w') || (sb->sym[0] == 'W');
 715         if (wa != wb)
 716                 return wa - wb;
 717
 718         /* sort by "linker script provide" type */
 719         wa = may_be_linker_script_provide_symbol(sa);
 720         wb = may_be_linker_script_provide_symbol(sb);
 721         if (wa != wb)
 722                 return wa - wb;
 723
 724         /* sort by the number of prefix underscores */
 725         wa = prefix_underscores_count((const char *)sa->sym + 1);
 726         wb = prefix_underscores_count((const char *)sb->sym + 1);
 727         if (wa != wb)
 728                 return wa - wb;
 729
 730         /* sort by initial order, so that other symbols are left undisturbed */
 731         return sa->start_pos - sb->start_pos;
 732 }
 733
 734 static void sort_symbols(void)
 735 {
 736         qsort(table, table_cnt, sizeof(struct sym_entry), compare_symbols);
 737 }
 738
 739 static void make_percpus_absolute(void)
 740 {
 741         unsigned int i;
 742
 743         for (i = 0; i < table_cnt; i++)
 744                 if (symbol_in_range(&table[i], &percpu_range, 1)) {
 745                         /*
 746                          * Keep the 'A' override for percpu symbols to
 747                          * ensure consistent behavior compared to older
 748                          * versions of this tool.
 749                          */
 750                         table[i].sym[0] = 'A';
 751                         table[i].percpu_absolute = 1;
 752                 }
 753 }
 754
 755 /* find the minimum non-absolute symbol address */
 756 static void record_relative_base(void)
 757 {
 758         unsigned int i;
 759
 760         relative_base = -1ULL;
 761         for (i = 0; i < table_cnt; i++)
 762                 if (!symbol_absolute(&table[i]) &&
 763                     table[i].addr < relative_base)
 764                         relative_base = table[i].addr;
 765 }
 766
 767 int main(int argc, char **argv)
 768 {
 769         if (argc >= 2) {
 770                 int i;
 771                 for (i = 1; i < argc; i++) {
 772                         if(strcmp(argv[i], "--all-symbols") == 0)
 773                                 all_symbols = 1;
 774                         else if (strcmp(argv[i], "--absolute-percpu") == 0)
 775                                 absolute_percpu = 1;
 776                         else if (strncmp(argv[i], "--symbol-prefix=", 16) == 0) {
 777                                 char *p = &argv[i][16];
 778                                 /* skip quote */
 779                                 if ((*p == '"' && *(p+2) == '"') || (*p == '\'' && *(p+2) == '\''))
 780                                         p++;
 781                                 symbol_prefix_char = *p;
 782                         } else if (strcmp(argv[i], "--base-relative") == 0)
 783                                 base_relative = 1;
 784                         else
 785                                 usage();
 786                 }
 787         } else if (argc != 1)
 788                 usage();
 789
 790         read_map(stdin);
 791         if (absolute_percpu)
 792                 make_percpus_absolute();
 793         if (base_relative)
 794                 record_relative_base();
 795         sort_symbols();
 796         optimize_token_table();
 797         write_src();
 798
 799         return 0;
 800 }