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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
35struct 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
44struct addr_range {
45 const char *start_sym, *end_sym;
46 unsigned long long start, end;
47};
48
49static unsigned long long _text;
50static unsigned long long relative_base;
51static 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
58static struct addr_range percpu_range = {
59 "__per_cpu_start", "__per_cpu_end", -1ULL, 0
60};
61
62static struct sym_entry **table;
63static unsigned int table_size, table_cnt;
64static int all_symbols;
65static int absolute_percpu;
66static int base_relative;
67static int lto_clang;
68
69static int token_profit[0x10000];
70
71/* the table that holds the result of the compression */
72static unsigned char best_table[256][2];
73static unsigned char best_table_len[256];
74
75
76static 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
83static char *sym_name(const struct sym_entry *s)
84{
85 return (char *)s->sym + 1;
86}
87
88static 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
105static 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
124static 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
191static 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
207static 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 */
234static 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
257static 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
294static 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. */
302static 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 */
312static 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
337static int symbol_absolute(const struct sym_entry *s)
338{
339 return s->percpu_absolute;
340}
341
342static 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
361static 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
381static void sort_symbols_by_name(void)
382{
383 qsort(table, table_cnt, sizeof(table[0]), compare_names);
384}
385
386static 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 */
554static 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 */
563static 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 */
572static 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
580static 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 */
594static 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 */
636static 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 */
653static 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 */
682static 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
695static 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 */
705static 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
739static 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
773static void sort_symbols(void)
774{
775 qsort(table, table_cnt, sizeof(table[0]), compare_symbols);
776}
777
778static 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 */
795static 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
810int 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}
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] 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 <getopt.h>
23#include <stdbool.h>
24#include <stdio.h>
25#include <stdlib.h>
26#include <string.h>
27#include <ctype.h>
28#include <limits.h>
29
30#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof(arr[0]))
31
32#define _stringify_1(x) #x
33#define _stringify(x) _stringify_1(x)
34
35#define KSYM_NAME_LEN 512
36
37/*
38 * A substantially bigger size than the current maximum.
39 *
40 * It cannot be defined as an expression because it gets stringified
41 * for the fscanf() format string. Therefore, a _Static_assert() is
42 * used instead to maintain the relationship with KSYM_NAME_LEN.
43 */
44#define KSYM_NAME_LEN_BUFFER 2048
45_Static_assert(
46 KSYM_NAME_LEN_BUFFER == KSYM_NAME_LEN * 4,
47 "Please keep KSYM_NAME_LEN_BUFFER in sync with KSYM_NAME_LEN"
48);
49
50struct sym_entry {
51 unsigned long long addr;
52 unsigned int len;
53 unsigned int seq;
54 unsigned int start_pos;
55 unsigned int percpu_absolute;
56 unsigned char sym[];
57};
58
59struct addr_range {
60 const char *start_sym, *end_sym;
61 unsigned long long start, end;
62};
63
64static unsigned long long _text;
65static unsigned long long relative_base;
66static struct addr_range text_ranges[] = {
67 { "_stext", "_etext" },
68 { "_sinittext", "_einittext" },
69};
70#define text_range_text (&text_ranges[0])
71#define text_range_inittext (&text_ranges[1])
72
73static struct addr_range percpu_range = {
74 "__per_cpu_start", "__per_cpu_end", -1ULL, 0
75};
76
77static struct sym_entry **table;
78static unsigned int table_size, table_cnt;
79static int all_symbols;
80static int absolute_percpu;
81static int base_relative;
82static int lto_clang;
83
84static int token_profit[0x10000];
85
86/* the table that holds the result of the compression */
87static unsigned char best_table[256][2];
88static unsigned char best_table_len[256];
89
90
91static void usage(void)
92{
93 fprintf(stderr, "Usage: kallsyms [--all-symbols] [--absolute-percpu] "
94 "[--base-relative] [--lto-clang] in.map > out.S\n");
95 exit(1);
96}
97
98static char *sym_name(const struct sym_entry *s)
99{
100 return (char *)s->sym + 1;
101}
102
103static bool is_ignored_symbol(const char *name, char type)
104{
105 /* Symbol names that exactly match to the following are ignored.*/
106 static const char * const ignored_symbols[] = {
107 /*
108 * Symbols which vary between passes. Passes 1 and 2 must have
109 * identical symbol lists. The kallsyms_* symbols below are
110 * only added after pass 1, they would be included in pass 2
111 * when --all-symbols is specified so exclude them to get a
112 * stable symbol list.
113 */
114 "kallsyms_addresses",
115 "kallsyms_offsets",
116 "kallsyms_relative_base",
117 "kallsyms_num_syms",
118 "kallsyms_names",
119 "kallsyms_markers",
120 "kallsyms_token_table",
121 "kallsyms_token_index",
122 /* Exclude linker generated symbols which vary between passes */
123 "_SDA_BASE_", /* ppc */
124 "_SDA2_BASE_", /* ppc */
125 NULL
126 };
127
128 /* Symbol names that begin with the following are ignored.*/
129 static const char * const ignored_prefixes[] = {
130 "__efistub_", /* arm64 EFI stub namespace */
131 "__kvm_nvhe_$", /* arm64 local symbols in non-VHE KVM namespace */
132 "__kvm_nvhe_.L", /* arm64 local symbols in non-VHE KVM namespace */
133 "__AArch64ADRPThunk_", /* arm64 lld */
134 "__ARMV5PILongThunk_", /* arm lld */
135 "__ARMV7PILongThunk_",
136 "__ThumbV7PILongThunk_",
137 "__LA25Thunk_", /* mips lld */
138 "__microLA25Thunk_",
139 "__kcfi_typeid_", /* CFI type identifiers */
140 NULL
141 };
142
143 /* Symbol names that end with the following are ignored.*/
144 static const char * const ignored_suffixes[] = {
145 "_from_arm", /* arm */
146 "_from_thumb", /* arm */
147 "_veneer", /* arm */
148 NULL
149 };
150
151 /* Symbol names that contain the following are ignored.*/
152 static const char * const ignored_matches[] = {
153 ".long_branch.", /* ppc stub */
154 ".plt_branch.", /* ppc stub */
155 NULL
156 };
157
158 const char * const *p;
159
160 for (p = ignored_symbols; *p; p++)
161 if (!strcmp(name, *p))
162 return true;
163
164 for (p = ignored_prefixes; *p; p++)
165 if (!strncmp(name, *p, strlen(*p)))
166 return true;
167
168 for (p = ignored_suffixes; *p; p++) {
169 int l = strlen(name) - strlen(*p);
170
171 if (l >= 0 && !strcmp(name + l, *p))
172 return true;
173 }
174
175 for (p = ignored_matches; *p; p++) {
176 if (strstr(name, *p))
177 return true;
178 }
179
180 if (type == 'U' || type == 'u')
181 return true;
182 /* exclude debugging symbols */
183 if (type == 'N' || type == 'n')
184 return true;
185
186 if (toupper(type) == 'A') {
187 /* Keep these useful absolute symbols */
188 if (strcmp(name, "__kernel_syscall_via_break") &&
189 strcmp(name, "__kernel_syscall_via_epc") &&
190 strcmp(name, "__kernel_sigtramp") &&
191 strcmp(name, "__gp"))
192 return true;
193 }
194
195 return false;
196}
197
198static void check_symbol_range(const char *sym, unsigned long long addr,
199 struct addr_range *ranges, int entries)
200{
201 size_t i;
202 struct addr_range *ar;
203
204 for (i = 0; i < entries; ++i) {
205 ar = &ranges[i];
206
207 if (strcmp(sym, ar->start_sym) == 0) {
208 ar->start = addr;
209 return;
210 } else if (strcmp(sym, ar->end_sym) == 0) {
211 ar->end = addr;
212 return;
213 }
214 }
215}
216
217static struct sym_entry *read_symbol(FILE *in)
218{
219 char name[KSYM_NAME_LEN_BUFFER+1], type;
220 unsigned long long addr;
221 unsigned int len;
222 struct sym_entry *sym;
223 int rc;
224
225 rc = fscanf(in, "%llx %c %" _stringify(KSYM_NAME_LEN_BUFFER) "s\n", &addr, &type, name);
226 if (rc != 3) {
227 if (rc != EOF && fgets(name, ARRAY_SIZE(name), in) == NULL)
228 fprintf(stderr, "Read error or end of file.\n");
229 return NULL;
230 }
231 if (strlen(name) >= KSYM_NAME_LEN) {
232 fprintf(stderr, "Symbol %s too long for kallsyms (%zu >= %d).\n"
233 "Please increase KSYM_NAME_LEN both in kernel and kallsyms.c\n",
234 name, strlen(name), KSYM_NAME_LEN);
235 return NULL;
236 }
237
238 if (strcmp(name, "_text") == 0)
239 _text = addr;
240
241 /* Ignore most absolute/undefined (?) symbols. */
242 if (is_ignored_symbol(name, type))
243 return NULL;
244
245 check_symbol_range(name, addr, text_ranges, ARRAY_SIZE(text_ranges));
246 check_symbol_range(name, addr, &percpu_range, 1);
247
248 /* include the type field in the symbol name, so that it gets
249 * compressed together */
250
251 len = strlen(name) + 1;
252
253 sym = malloc(sizeof(*sym) + len + 1);
254 if (!sym) {
255 fprintf(stderr, "kallsyms failure: "
256 "unable to allocate required amount of memory\n");
257 exit(EXIT_FAILURE);
258 }
259 sym->addr = addr;
260 sym->len = len;
261 sym->sym[0] = type;
262 strcpy(sym_name(sym), name);
263 sym->percpu_absolute = 0;
264
265 return sym;
266}
267
268static int symbol_in_range(const struct sym_entry *s,
269 const struct addr_range *ranges, int entries)
270{
271 size_t i;
272 const struct addr_range *ar;
273
274 for (i = 0; i < entries; ++i) {
275 ar = &ranges[i];
276
277 if (s->addr >= ar->start && s->addr <= ar->end)
278 return 1;
279 }
280
281 return 0;
282}
283
284static int symbol_valid(const struct sym_entry *s)
285{
286 const char *name = sym_name(s);
287
288 /* if --all-symbols is not specified, then symbols outside the text
289 * and inittext sections are discarded */
290 if (!all_symbols) {
291 if (symbol_in_range(s, text_ranges,
292 ARRAY_SIZE(text_ranges)) == 0)
293 return 0;
294 /* Corner case. Discard any symbols with the same value as
295 * _etext _einittext; they can move between pass 1 and 2 when
296 * the kallsyms data are added. If these symbols move then
297 * they may get dropped in pass 2, which breaks the kallsyms
298 * rules.
299 */
300 if ((s->addr == text_range_text->end &&
301 strcmp(name, text_range_text->end_sym)) ||
302 (s->addr == text_range_inittext->end &&
303 strcmp(name, text_range_inittext->end_sym)))
304 return 0;
305 }
306
307 return 1;
308}
309
310/* remove all the invalid symbols from the table */
311static void shrink_table(void)
312{
313 unsigned int i, pos;
314
315 pos = 0;
316 for (i = 0; i < table_cnt; i++) {
317 if (symbol_valid(table[i])) {
318 if (pos != i)
319 table[pos] = table[i];
320 pos++;
321 } else {
322 free(table[i]);
323 }
324 }
325 table_cnt = pos;
326
327 /* When valid symbol is not registered, exit to error */
328 if (!table_cnt) {
329 fprintf(stderr, "No valid symbol.\n");
330 exit(1);
331 }
332}
333
334static void read_map(const char *in)
335{
336 FILE *fp;
337 struct sym_entry *sym;
338
339 fp = fopen(in, "r");
340 if (!fp) {
341 perror(in);
342 exit(1);
343 }
344
345 while (!feof(fp)) {
346 sym = read_symbol(fp);
347 if (!sym)
348 continue;
349
350 sym->start_pos = table_cnt;
351
352 if (table_cnt >= table_size) {
353 table_size += 10000;
354 table = realloc(table, sizeof(*table) * table_size);
355 if (!table) {
356 fprintf(stderr, "out of memory\n");
357 fclose(fp);
358 exit (1);
359 }
360 }
361
362 table[table_cnt++] = sym;
363 }
364
365 fclose(fp);
366}
367
368static void output_label(const char *label)
369{
370 printf(".globl %s\n", label);
371 printf("\tALGN\n");
372 printf("%s:\n", label);
373}
374
375/* Provide proper symbols relocatability by their '_text' relativeness. */
376static void output_address(unsigned long long addr)
377{
378 if (_text <= addr)
379 printf("\tPTR\t_text + %#llx\n", addr - _text);
380 else
381 printf("\tPTR\t_text - %#llx\n", _text - addr);
382}
383
384/* uncompress a compressed symbol. When this function is called, the best table
385 * might still be compressed itself, so the function needs to be recursive */
386static int expand_symbol(const unsigned char *data, int len, char *result)
387{
388 int c, rlen, total=0;
389
390 while (len) {
391 c = *data;
392 /* if the table holds a single char that is the same as the one
393 * we are looking for, then end the search */
394 if (best_table[c][0]==c && best_table_len[c]==1) {
395 *result++ = c;
396 total++;
397 } else {
398 /* if not, recurse and expand */
399 rlen = expand_symbol(best_table[c], best_table_len[c], result);
400 total += rlen;
401 result += rlen;
402 }
403 data++;
404 len--;
405 }
406 *result=0;
407
408 return total;
409}
410
411static int symbol_absolute(const struct sym_entry *s)
412{
413 return s->percpu_absolute;
414}
415
416static char * s_name(char *buf)
417{
418 /* Skip the symbol type */
419 return buf + 1;
420}
421
422static void cleanup_symbol_name(char *s)
423{
424 char *p;
425
426 if (!lto_clang)
427 return;
428
429 /*
430 * ASCII[.] = 2e
431 * ASCII[0-9] = 30,39
432 * ASCII[A-Z] = 41,5a
433 * ASCII[_] = 5f
434 * ASCII[a-z] = 61,7a
435 *
436 * As above, replacing '.' with '\0' does not affect the main sorting,
437 * but it helps us with subsorting.
438 */
439 p = strchr(s, '.');
440 if (p)
441 *p = '\0';
442}
443
444static int compare_names(const void *a, const void *b)
445{
446 int ret;
447 char sa_namebuf[KSYM_NAME_LEN];
448 char sb_namebuf[KSYM_NAME_LEN];
449 const struct sym_entry *sa = *(const struct sym_entry **)a;
450 const struct sym_entry *sb = *(const struct sym_entry **)b;
451
452 expand_symbol(sa->sym, sa->len, sa_namebuf);
453 expand_symbol(sb->sym, sb->len, sb_namebuf);
454 cleanup_symbol_name(s_name(sa_namebuf));
455 cleanup_symbol_name(s_name(sb_namebuf));
456 ret = strcmp(s_name(sa_namebuf), s_name(sb_namebuf));
457 if (!ret) {
458 if (sa->addr > sb->addr)
459 return 1;
460 else if (sa->addr < sb->addr)
461 return -1;
462
463 /* keep old order */
464 return (int)(sa->seq - sb->seq);
465 }
466
467 return ret;
468}
469
470static void sort_symbols_by_name(void)
471{
472 qsort(table, table_cnt, sizeof(table[0]), compare_names);
473}
474
475static void write_src(void)
476{
477 unsigned int i, k, off;
478 unsigned int best_idx[256];
479 unsigned int *markers;
480 char buf[KSYM_NAME_LEN];
481
482 printf("#include <asm/bitsperlong.h>\n");
483 printf("#if BITS_PER_LONG == 64\n");
484 printf("#define PTR .quad\n");
485 printf("#define ALGN .balign 8\n");
486 printf("#else\n");
487 printf("#define PTR .long\n");
488 printf("#define ALGN .balign 4\n");
489 printf("#endif\n");
490
491 printf("\t.section .rodata, \"a\"\n");
492
493 if (!base_relative)
494 output_label("kallsyms_addresses");
495 else
496 output_label("kallsyms_offsets");
497
498 for (i = 0; i < table_cnt; i++) {
499 if (base_relative) {
500 /*
501 * Use the offset relative to the lowest value
502 * encountered of all relative symbols, and emit
503 * non-relocatable fixed offsets that will be fixed
504 * up at runtime.
505 */
506
507 long long offset;
508 int overflow;
509
510 if (!absolute_percpu) {
511 offset = table[i]->addr - relative_base;
512 overflow = (offset < 0 || offset > UINT_MAX);
513 } else if (symbol_absolute(table[i])) {
514 offset = table[i]->addr;
515 overflow = (offset < 0 || offset > INT_MAX);
516 } else {
517 offset = relative_base - table[i]->addr - 1;
518 overflow = (offset < INT_MIN || offset >= 0);
519 }
520 if (overflow) {
521 fprintf(stderr, "kallsyms failure: "
522 "%s symbol value %#llx out of range in relative mode\n",
523 symbol_absolute(table[i]) ? "absolute" : "relative",
524 table[i]->addr);
525 exit(EXIT_FAILURE);
526 }
527 printf("\t.long\t%#x\n", (int)offset);
528 } else if (!symbol_absolute(table[i])) {
529 output_address(table[i]->addr);
530 } else {
531 printf("\tPTR\t%#llx\n", table[i]->addr);
532 }
533 }
534 printf("\n");
535
536 if (base_relative) {
537 output_label("kallsyms_relative_base");
538 output_address(relative_base);
539 printf("\n");
540 }
541
542 output_label("kallsyms_num_syms");
543 printf("\t.long\t%u\n", table_cnt);
544 printf("\n");
545
546 /* table of offset markers, that give the offset in the compressed stream
547 * every 256 symbols */
548 markers = malloc(sizeof(unsigned int) * ((table_cnt + 255) / 256));
549 if (!markers) {
550 fprintf(stderr, "kallsyms failure: "
551 "unable to allocate required memory\n");
552 exit(EXIT_FAILURE);
553 }
554
555 output_label("kallsyms_names");
556 off = 0;
557 for (i = 0; i < table_cnt; i++) {
558 if ((i & 0xFF) == 0)
559 markers[i >> 8] = off;
560 table[i]->seq = i;
561
562 /* There cannot be any symbol of length zero. */
563 if (table[i]->len == 0) {
564 fprintf(stderr, "kallsyms failure: "
565 "unexpected zero symbol length\n");
566 exit(EXIT_FAILURE);
567 }
568
569 /* Only lengths that fit in up-to-two-byte ULEB128 are supported. */
570 if (table[i]->len > 0x3FFF) {
571 fprintf(stderr, "kallsyms failure: "
572 "unexpected huge symbol length\n");
573 exit(EXIT_FAILURE);
574 }
575
576 /* Encode length with ULEB128. */
577 if (table[i]->len <= 0x7F) {
578 /* Most symbols use a single byte for the length. */
579 printf("\t.byte 0x%02x", table[i]->len);
580 off += table[i]->len + 1;
581 } else {
582 /* "Big" symbols use two bytes. */
583 printf("\t.byte 0x%02x, 0x%02x",
584 (table[i]->len & 0x7F) | 0x80,
585 (table[i]->len >> 7) & 0x7F);
586 off += table[i]->len + 2;
587 }
588 for (k = 0; k < table[i]->len; k++)
589 printf(", 0x%02x", table[i]->sym[k]);
590 printf("\n");
591 }
592 printf("\n");
593
594 output_label("kallsyms_markers");
595 for (i = 0; i < ((table_cnt + 255) >> 8); i++)
596 printf("\t.long\t%u\n", markers[i]);
597 printf("\n");
598
599 free(markers);
600
601 sort_symbols_by_name();
602 output_label("kallsyms_seqs_of_names");
603 for (i = 0; i < table_cnt; i++)
604 printf("\t.byte 0x%02x, 0x%02x, 0x%02x\n",
605 (unsigned char)(table[i]->seq >> 16),
606 (unsigned char)(table[i]->seq >> 8),
607 (unsigned char)(table[i]->seq >> 0));
608 printf("\n");
609
610 output_label("kallsyms_token_table");
611 off = 0;
612 for (i = 0; i < 256; i++) {
613 best_idx[i] = off;
614 expand_symbol(best_table[i], best_table_len[i], buf);
615 printf("\t.asciz\t\"%s\"\n", buf);
616 off += strlen(buf) + 1;
617 }
618 printf("\n");
619
620 output_label("kallsyms_token_index");
621 for (i = 0; i < 256; i++)
622 printf("\t.short\t%d\n", best_idx[i]);
623 printf("\n");
624}
625
626
627/* table lookup compression functions */
628
629/* count all the possible tokens in a symbol */
630static void learn_symbol(const unsigned char *symbol, int len)
631{
632 int i;
633
634 for (i = 0; i < len - 1; i++)
635 token_profit[ symbol[i] + (symbol[i + 1] << 8) ]++;
636}
637
638/* decrease the count for all the possible tokens in a symbol */
639static void forget_symbol(const unsigned char *symbol, int len)
640{
641 int i;
642
643 for (i = 0; i < len - 1; i++)
644 token_profit[ symbol[i] + (symbol[i + 1] << 8) ]--;
645}
646
647/* do the initial token count */
648static void build_initial_token_table(void)
649{
650 unsigned int i;
651
652 for (i = 0; i < table_cnt; i++)
653 learn_symbol(table[i]->sym, table[i]->len);
654}
655
656static unsigned char *find_token(unsigned char *str, int len,
657 const unsigned char *token)
658{
659 int i;
660
661 for (i = 0; i < len - 1; i++) {
662 if (str[i] == token[0] && str[i+1] == token[1])
663 return &str[i];
664 }
665 return NULL;
666}
667
668/* replace a given token in all the valid symbols. Use the sampled symbols
669 * to update the counts */
670static void compress_symbols(const unsigned char *str, int idx)
671{
672 unsigned int i, len, size;
673 unsigned char *p1, *p2;
674
675 for (i = 0; i < table_cnt; i++) {
676
677 len = table[i]->len;
678 p1 = table[i]->sym;
679
680 /* find the token on the symbol */
681 p2 = find_token(p1, len, str);
682 if (!p2) continue;
683
684 /* decrease the counts for this symbol's tokens */
685 forget_symbol(table[i]->sym, len);
686
687 size = len;
688
689 do {
690 *p2 = idx;
691 p2++;
692 size -= (p2 - p1);
693 memmove(p2, p2 + 1, size);
694 p1 = p2;
695 len--;
696
697 if (size < 2) break;
698
699 /* find the token on the symbol */
700 p2 = find_token(p1, size, str);
701
702 } while (p2);
703
704 table[i]->len = len;
705
706 /* increase the counts for this symbol's new tokens */
707 learn_symbol(table[i]->sym, len);
708 }
709}
710
711/* search the token with the maximum profit */
712static int find_best_token(void)
713{
714 int i, best, bestprofit;
715
716 bestprofit=-10000;
717 best = 0;
718
719 for (i = 0; i < 0x10000; i++) {
720 if (token_profit[i] > bestprofit) {
721 best = i;
722 bestprofit = token_profit[i];
723 }
724 }
725 return best;
726}
727
728/* this is the core of the algorithm: calculate the "best" table */
729static void optimize_result(void)
730{
731 int i, best;
732
733 /* using the '\0' symbol last allows compress_symbols to use standard
734 * fast string functions */
735 for (i = 255; i >= 0; i--) {
736
737 /* if this table slot is empty (it is not used by an actual
738 * original char code */
739 if (!best_table_len[i]) {
740
741 /* find the token with the best profit value */
742 best = find_best_token();
743 if (token_profit[best] == 0)
744 break;
745
746 /* place it in the "best" table */
747 best_table_len[i] = 2;
748 best_table[i][0] = best & 0xFF;
749 best_table[i][1] = (best >> 8) & 0xFF;
750
751 /* replace this token in all the valid symbols */
752 compress_symbols(best_table[i], i);
753 }
754 }
755}
756
757/* start by placing the symbols that are actually used on the table */
758static void insert_real_symbols_in_table(void)
759{
760 unsigned int i, j, c;
761
762 for (i = 0; i < table_cnt; i++) {
763 for (j = 0; j < table[i]->len; j++) {
764 c = table[i]->sym[j];
765 best_table[c][0]=c;
766 best_table_len[c]=1;
767 }
768 }
769}
770
771static void optimize_token_table(void)
772{
773 build_initial_token_table();
774
775 insert_real_symbols_in_table();
776
777 optimize_result();
778}
779
780/* guess for "linker script provide" symbol */
781static int may_be_linker_script_provide_symbol(const struct sym_entry *se)
782{
783 const char *symbol = sym_name(se);
784 int len = se->len - 1;
785
786 if (len < 8)
787 return 0;
788
789 if (symbol[0] != '_' || symbol[1] != '_')
790 return 0;
791
792 /* __start_XXXXX */
793 if (!memcmp(symbol + 2, "start_", 6))
794 return 1;
795
796 /* __stop_XXXXX */
797 if (!memcmp(symbol + 2, "stop_", 5))
798 return 1;
799
800 /* __end_XXXXX */
801 if (!memcmp(symbol + 2, "end_", 4))
802 return 1;
803
804 /* __XXXXX_start */
805 if (!memcmp(symbol + len - 6, "_start", 6))
806 return 1;
807
808 /* __XXXXX_end */
809 if (!memcmp(symbol + len - 4, "_end", 4))
810 return 1;
811
812 return 0;
813}
814
815static int compare_symbols(const void *a, const void *b)
816{
817 const struct sym_entry *sa = *(const struct sym_entry **)a;
818 const struct sym_entry *sb = *(const struct sym_entry **)b;
819 int wa, wb;
820
821 /* sort by address first */
822 if (sa->addr > sb->addr)
823 return 1;
824 if (sa->addr < sb->addr)
825 return -1;
826
827 /* sort by "weakness" type */
828 wa = (sa->sym[0] == 'w') || (sa->sym[0] == 'W');
829 wb = (sb->sym[0] == 'w') || (sb->sym[0] == 'W');
830 if (wa != wb)
831 return wa - wb;
832
833 /* sort by "linker script provide" type */
834 wa = may_be_linker_script_provide_symbol(sa);
835 wb = may_be_linker_script_provide_symbol(sb);
836 if (wa != wb)
837 return wa - wb;
838
839 /* sort by the number of prefix underscores */
840 wa = strspn(sym_name(sa), "_");
841 wb = strspn(sym_name(sb), "_");
842 if (wa != wb)
843 return wa - wb;
844
845 /* sort by initial order, so that other symbols are left undisturbed */
846 return sa->start_pos - sb->start_pos;
847}
848
849static void sort_symbols(void)
850{
851 qsort(table, table_cnt, sizeof(table[0]), compare_symbols);
852}
853
854static void make_percpus_absolute(void)
855{
856 unsigned int i;
857
858 for (i = 0; i < table_cnt; i++)
859 if (symbol_in_range(table[i], &percpu_range, 1)) {
860 /*
861 * Keep the 'A' override for percpu symbols to
862 * ensure consistent behavior compared to older
863 * versions of this tool.
864 */
865 table[i]->sym[0] = 'A';
866 table[i]->percpu_absolute = 1;
867 }
868}
869
870/* find the minimum non-absolute symbol address */
871static void record_relative_base(void)
872{
873 unsigned int i;
874
875 for (i = 0; i < table_cnt; i++)
876 if (!symbol_absolute(table[i])) {
877 /*
878 * The table is sorted by address.
879 * Take the first non-absolute symbol value.
880 */
881 relative_base = table[i]->addr;
882 return;
883 }
884}
885
886int main(int argc, char **argv)
887{
888 while (1) {
889 static struct option long_options[] = {
890 {"all-symbols", no_argument, &all_symbols, 1},
891 {"absolute-percpu", no_argument, &absolute_percpu, 1},
892 {"base-relative", no_argument, &base_relative, 1},
893 {"lto-clang", no_argument, <o_clang, 1},
894 {},
895 };
896
897 int c = getopt_long(argc, argv, "", long_options, NULL);
898
899 if (c == -1)
900 break;
901 if (c != 0)
902 usage();
903 }
904
905 if (optind >= argc)
906 usage();
907
908 read_map(argv[optind]);
909 shrink_table();
910 if (absolute_percpu)
911 make_percpus_absolute();
912 sort_symbols();
913 if (base_relative)
914 record_relative_base();
915 optimize_token_table();
916 write_src();
917
918 return 0;
919}