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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: 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 | |
26 | #ifndef ARRAY_SIZE |
27 | #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof(arr[0])) |
28 | #endif |
29 | |
30 | #define KSYM_NAME_LEN 128 |
31 | |
32 | struct sym_entry { |
33 | unsigned long long addr; |
34 | unsigned int len; |
35 | unsigned int start_pos; |
36 | unsigned char *sym; |
37 | }; |
38 | |
39 | struct text_range { |
40 | const char *stext, *etext; |
41 | unsigned long long start, end; |
42 | }; |
43 | |
44 | static unsigned long long _text; |
45 | static struct text_range text_ranges[] = { |
46 | { "_stext", "_etext" }, |
47 | { "_sinittext", "_einittext" }, |
48 | { "_stext_l1", "_etext_l1" }, /* Blackfin on-chip L1 inst SRAM */ |
49 | { "_stext_l2", "_etext_l2" }, /* Blackfin on-chip L2 SRAM */ |
50 | }; |
51 | #define text_range_text (&text_ranges[0]) |
52 | #define text_range_inittext (&text_ranges[1]) |
53 | |
54 | static struct sym_entry *table; |
55 | static unsigned int table_size, table_cnt; |
56 | static int all_symbols = 0; |
57 | static char symbol_prefix_char = '\0'; |
58 | |
59 | int token_profit[0x10000]; |
60 | |
61 | /* the table that holds the result of the compression */ |
62 | unsigned char best_table[256][2]; |
63 | unsigned char best_table_len[256]; |
64 | |
65 | |
66 | static void usage(void) |
67 | { |
68 | fprintf(stderr, "Usage: kallsyms [--all-symbols] [--symbol-prefix=<prefix char>] < in.map > out.S\n"); |
69 | exit(1); |
70 | } |
71 | |
72 | /* |
73 | * This ignores the intensely annoying "mapping symbols" found |
74 | * in ARM ELF files: $a, $t and $d. |
75 | */ |
76 | static inline int is_arm_mapping_symbol(const char *str) |
77 | { |
78 | return str[0] == '$' && strchr("atd", str[1]) |
79 | && (str[2] == '\0' || str[2] == '.'); |
80 | } |
81 | |
82 | static int read_symbol_tr(const char *sym, unsigned long long addr) |
83 | { |
84 | size_t i; |
85 | struct text_range *tr; |
86 | |
87 | for (i = 0; i < ARRAY_SIZE(text_ranges); ++i) { |
88 | tr = &text_ranges[i]; |
89 | |
90 | if (strcmp(sym, tr->stext) == 0) { |
91 | tr->start = addr; |
92 | return 0; |
93 | } else if (strcmp(sym, tr->etext) == 0) { |
94 | tr->end = addr; |
95 | return 0; |
96 | } |
97 | } |
98 | |
99 | return 1; |
100 | } |
101 | |
102 | static int read_symbol(FILE *in, struct sym_entry *s) |
103 | { |
104 | char str[500]; |
105 | char *sym, stype; |
106 | int rc; |
107 | |
108 | rc = fscanf(in, "%llx %c %499s\n", &s->addr, &stype, str); |
109 | if (rc != 3) { |
110 | if (rc != EOF && fgets(str, 500, in) == NULL) |
111 | fprintf(stderr, "Read error or end of file.\n"); |
112 | return -1; |
113 | } |
114 | |
115 | sym = str; |
116 | /* skip prefix char */ |
117 | if (symbol_prefix_char && str[0] == symbol_prefix_char) |
118 | sym++; |
119 | |
120 | /* Ignore most absolute/undefined (?) symbols. */ |
121 | if (strcmp(sym, "_text") == 0) |
122 | _text = s->addr; |
123 | else if (read_symbol_tr(sym, s->addr) == 0) |
124 | /* nothing to do */; |
125 | else if (toupper(stype) == 'A') |
126 | { |
127 | /* Keep these useful absolute symbols */ |
128 | if (strcmp(sym, "__kernel_syscall_via_break") && |
129 | strcmp(sym, "__kernel_syscall_via_epc") && |
130 | strcmp(sym, "__kernel_sigtramp") && |
131 | strcmp(sym, "__gp")) |
132 | return -1; |
133 | |
134 | } |
135 | else if (toupper(stype) == 'U' || |
136 | is_arm_mapping_symbol(sym)) |
137 | return -1; |
138 | /* exclude also MIPS ELF local symbols ($L123 instead of .L123) */ |
139 | else if (str[0] == '$') |
140 | return -1; |
141 | /* exclude debugging symbols */ |
142 | else if (stype == 'N') |
143 | return -1; |
144 | |
145 | /* include the type field in the symbol name, so that it gets |
146 | * compressed together */ |
147 | s->len = strlen(str) + 1; |
148 | s->sym = malloc(s->len + 1); |
149 | if (!s->sym) { |
150 | fprintf(stderr, "kallsyms failure: " |
151 | "unable to allocate required amount of memory\n"); |
152 | exit(EXIT_FAILURE); |
153 | } |
154 | strcpy((char *)s->sym + 1, str); |
155 | s->sym[0] = stype; |
156 | |
157 | return 0; |
158 | } |
159 | |
160 | static int symbol_valid_tr(struct sym_entry *s) |
161 | { |
162 | size_t i; |
163 | struct text_range *tr; |
164 | |
165 | for (i = 0; i < ARRAY_SIZE(text_ranges); ++i) { |
166 | tr = &text_ranges[i]; |
167 | |
168 | if (s->addr >= tr->start && s->addr <= tr->end) |
169 | return 1; |
170 | } |
171 | |
172 | return 0; |
173 | } |
174 | |
175 | static int symbol_valid(struct sym_entry *s) |
176 | { |
177 | /* Symbols which vary between passes. Passes 1 and 2 must have |
178 | * identical symbol lists. The kallsyms_* symbols below are only added |
179 | * after pass 1, they would be included in pass 2 when --all-symbols is |
180 | * specified so exclude them to get a stable symbol list. |
181 | */ |
182 | static char *special_symbols[] = { |
183 | "kallsyms_addresses", |
184 | "kallsyms_num_syms", |
185 | "kallsyms_names", |
186 | "kallsyms_markers", |
187 | "kallsyms_token_table", |
188 | "kallsyms_token_index", |
189 | |
190 | /* Exclude linker generated symbols which vary between passes */ |
191 | "_SDA_BASE_", /* ppc */ |
192 | "_SDA2_BASE_", /* ppc */ |
193 | NULL }; |
194 | int i; |
195 | int offset = 1; |
196 | |
197 | /* skip prefix char */ |
198 | if (symbol_prefix_char && *(s->sym + 1) == symbol_prefix_char) |
199 | offset++; |
200 | |
201 | /* if --all-symbols is not specified, then symbols outside the text |
202 | * and inittext sections are discarded */ |
203 | if (!all_symbols) { |
204 | if (symbol_valid_tr(s) == 0) |
205 | return 0; |
206 | /* Corner case. Discard any symbols with the same value as |
207 | * _etext _einittext; they can move between pass 1 and 2 when |
208 | * the kallsyms data are added. If these symbols move then |
209 | * they may get dropped in pass 2, which breaks the kallsyms |
210 | * rules. |
211 | */ |
212 | if ((s->addr == text_range_text->end && |
213 | strcmp((char *)s->sym + offset, text_range_text->etext)) || |
214 | (s->addr == text_range_inittext->end && |
215 | strcmp((char *)s->sym + offset, text_range_inittext->etext))) |
216 | return 0; |
217 | } |
218 | |
219 | /* Exclude symbols which vary between passes. */ |
220 | if (strstr((char *)s->sym + offset, "_compiled.")) |
221 | return 0; |
222 | |
223 | for (i = 0; special_symbols[i]; i++) |
224 | if( strcmp((char *)s->sym + offset, special_symbols[i]) == 0 ) |
225 | return 0; |
226 | |
227 | return 1; |
228 | } |
229 | |
230 | static void read_map(FILE *in) |
231 | { |
232 | while (!feof(in)) { |
233 | if (table_cnt >= table_size) { |
234 | table_size += 10000; |
235 | table = realloc(table, sizeof(*table) * table_size); |
236 | if (!table) { |
237 | fprintf(stderr, "out of memory\n"); |
238 | exit (1); |
239 | } |
240 | } |
241 | if (read_symbol(in, &table[table_cnt]) == 0) { |
242 | table[table_cnt].start_pos = table_cnt; |
243 | table_cnt++; |
244 | } |
245 | } |
246 | } |
247 | |
248 | static void output_label(char *label) |
249 | { |
250 | if (symbol_prefix_char) |
251 | printf(".globl %c%s\n", symbol_prefix_char, label); |
252 | else |
253 | printf(".globl %s\n", label); |
254 | printf("\tALGN\n"); |
255 | if (symbol_prefix_char) |
256 | printf("%c%s:\n", symbol_prefix_char, label); |
257 | else |
258 | printf("%s:\n", label); |
259 | } |
260 | |
261 | /* uncompress a compressed symbol. When this function is called, the best table |
262 | * might still be compressed itself, so the function needs to be recursive */ |
263 | static int expand_symbol(unsigned char *data, int len, char *result) |
264 | { |
265 | int c, rlen, total=0; |
266 | |
267 | while (len) { |
268 | c = *data; |
269 | /* if the table holds a single char that is the same as the one |
270 | * we are looking for, then end the search */ |
271 | if (best_table[c][0]==c && best_table_len[c]==1) { |
272 | *result++ = c; |
273 | total++; |
274 | } else { |
275 | /* if not, recurse and expand */ |
276 | rlen = expand_symbol(best_table[c], best_table_len[c], result); |
277 | total += rlen; |
278 | result += rlen; |
279 | } |
280 | data++; |
281 | len--; |
282 | } |
283 | *result=0; |
284 | |
285 | return total; |
286 | } |
287 | |
288 | static void write_src(void) |
289 | { |
290 | unsigned int i, k, off; |
291 | unsigned int best_idx[256]; |
292 | unsigned int *markers; |
293 | char buf[KSYM_NAME_LEN]; |
294 | |
295 | printf("#include <asm/types.h>\n"); |
296 | printf("#if BITS_PER_LONG == 64\n"); |
297 | printf("#define PTR .quad\n"); |
298 | printf("#define ALGN .align 8\n"); |
299 | printf("#else\n"); |
300 | printf("#define PTR .long\n"); |
301 | printf("#define ALGN .align 4\n"); |
302 | printf("#endif\n"); |
303 | |
304 | printf("\t.section .rodata, \"a\"\n"); |
305 | |
306 | /* Provide proper symbols relocatability by their '_text' |
307 | * relativeness. The symbol names cannot be used to construct |
308 | * normal symbol references as the list of symbols contains |
309 | * symbols that are declared static and are private to their |
310 | * .o files. This prevents .tmp_kallsyms.o or any other |
311 | * object from referencing them. |
312 | */ |
313 | output_label("kallsyms_addresses"); |
314 | for (i = 0; i < table_cnt; i++) { |
315 | if (toupper(table[i].sym[0]) != 'A') { |
316 | if (_text <= table[i].addr) |
317 | printf("\tPTR\t_text + %#llx\n", |
318 | table[i].addr - _text); |
319 | else |
320 | printf("\tPTR\t_text - %#llx\n", |
321 | _text - table[i].addr); |
322 | } else { |
323 | printf("\tPTR\t%#llx\n", table[i].addr); |
324 | } |
325 | } |
326 | printf("\n"); |
327 | |
328 | output_label("kallsyms_num_syms"); |
329 | printf("\tPTR\t%d\n", table_cnt); |
330 | printf("\n"); |
331 | |
332 | /* table of offset markers, that give the offset in the compressed stream |
333 | * every 256 symbols */ |
334 | markers = malloc(sizeof(unsigned int) * ((table_cnt + 255) / 256)); |
335 | if (!markers) { |
336 | fprintf(stderr, "kallsyms failure: " |
337 | "unable to allocate required memory\n"); |
338 | exit(EXIT_FAILURE); |
339 | } |
340 | |
341 | output_label("kallsyms_names"); |
342 | off = 0; |
343 | for (i = 0; i < table_cnt; i++) { |
344 | if ((i & 0xFF) == 0) |
345 | markers[i >> 8] = off; |
346 | |
347 | printf("\t.byte 0x%02x", table[i].len); |
348 | for (k = 0; k < table[i].len; k++) |
349 | printf(", 0x%02x", table[i].sym[k]); |
350 | printf("\n"); |
351 | |
352 | off += table[i].len + 1; |
353 | } |
354 | printf("\n"); |
355 | |
356 | output_label("kallsyms_markers"); |
357 | for (i = 0; i < ((table_cnt + 255) >> 8); i++) |
358 | printf("\tPTR\t%d\n", markers[i]); |
359 | printf("\n"); |
360 | |
361 | free(markers); |
362 | |
363 | output_label("kallsyms_token_table"); |
364 | off = 0; |
365 | for (i = 0; i < 256; i++) { |
366 | best_idx[i] = off; |
367 | expand_symbol(best_table[i], best_table_len[i], buf); |
368 | printf("\t.asciz\t\"%s\"\n", buf); |
369 | off += strlen(buf) + 1; |
370 | } |
371 | printf("\n"); |
372 | |
373 | output_label("kallsyms_token_index"); |
374 | for (i = 0; i < 256; i++) |
375 | printf("\t.short\t%d\n", best_idx[i]); |
376 | printf("\n"); |
377 | } |
378 | |
379 | |
380 | /* table lookup compression functions */ |
381 | |
382 | /* count all the possible tokens in a symbol */ |
383 | static void learn_symbol(unsigned char *symbol, int len) |
384 | { |
385 | int i; |
386 | |
387 | for (i = 0; i < len - 1; i++) |
388 | token_profit[ symbol[i] + (symbol[i + 1] << 8) ]++; |
389 | } |
390 | |
391 | /* decrease the count for all the possible tokens in a symbol */ |
392 | static void forget_symbol(unsigned char *symbol, int len) |
393 | { |
394 | int i; |
395 | |
396 | for (i = 0; i < len - 1; i++) |
397 | token_profit[ symbol[i] + (symbol[i + 1] << 8) ]--; |
398 | } |
399 | |
400 | /* remove all the invalid symbols from the table and do the initial token count */ |
401 | static void build_initial_tok_table(void) |
402 | { |
403 | unsigned int i, pos; |
404 | |
405 | pos = 0; |
406 | for (i = 0; i < table_cnt; i++) { |
407 | if ( symbol_valid(&table[i]) ) { |
408 | if (pos != i) |
409 | table[pos] = table[i]; |
410 | learn_symbol(table[pos].sym, table[pos].len); |
411 | pos++; |
412 | } |
413 | } |
414 | table_cnt = pos; |
415 | } |
416 | |
417 | static void *find_token(unsigned char *str, int len, unsigned char *token) |
418 | { |
419 | int i; |
420 | |
421 | for (i = 0; i < len - 1; i++) { |
422 | if (str[i] == token[0] && str[i+1] == token[1]) |
423 | return &str[i]; |
424 | } |
425 | return NULL; |
426 | } |
427 | |
428 | /* replace a given token in all the valid symbols. Use the sampled symbols |
429 | * to update the counts */ |
430 | static void compress_symbols(unsigned char *str, int idx) |
431 | { |
432 | unsigned int i, len, size; |
433 | unsigned char *p1, *p2; |
434 | |
435 | for (i = 0; i < table_cnt; i++) { |
436 | |
437 | len = table[i].len; |
438 | p1 = table[i].sym; |
439 | |
440 | /* find the token on the symbol */ |
441 | p2 = find_token(p1, len, str); |
442 | if (!p2) continue; |
443 | |
444 | /* decrease the counts for this symbol's tokens */ |
445 | forget_symbol(table[i].sym, len); |
446 | |
447 | size = len; |
448 | |
449 | do { |
450 | *p2 = idx; |
451 | p2++; |
452 | size -= (p2 - p1); |
453 | memmove(p2, p2 + 1, size); |
454 | p1 = p2; |
455 | len--; |
456 | |
457 | if (size < 2) break; |
458 | |
459 | /* find the token on the symbol */ |
460 | p2 = find_token(p1, size, str); |
461 | |
462 | } while (p2); |
463 | |
464 | table[i].len = len; |
465 | |
466 | /* increase the counts for this symbol's new tokens */ |
467 | learn_symbol(table[i].sym, len); |
468 | } |
469 | } |
470 | |
471 | /* search the token with the maximum profit */ |
472 | static int find_best_token(void) |
473 | { |
474 | int i, best, bestprofit; |
475 | |
476 | bestprofit=-10000; |
477 | best = 0; |
478 | |
479 | for (i = 0; i < 0x10000; i++) { |
480 | if (token_profit[i] > bestprofit) { |
481 | best = i; |
482 | bestprofit = token_profit[i]; |
483 | } |
484 | } |
485 | return best; |
486 | } |
487 | |
488 | /* this is the core of the algorithm: calculate the "best" table */ |
489 | static void optimize_result(void) |
490 | { |
491 | int i, best; |
492 | |
493 | /* using the '\0' symbol last allows compress_symbols to use standard |
494 | * fast string functions */ |
495 | for (i = 255; i >= 0; i--) { |
496 | |
497 | /* if this table slot is empty (it is not used by an actual |
498 | * original char code */ |
499 | if (!best_table_len[i]) { |
500 | |
501 | /* find the token with the breates profit value */ |
502 | best = find_best_token(); |
503 | |
504 | /* place it in the "best" table */ |
505 | best_table_len[i] = 2; |
506 | best_table[i][0] = best & 0xFF; |
507 | best_table[i][1] = (best >> 8) & 0xFF; |
508 | |
509 | /* replace this token in all the valid symbols */ |
510 | compress_symbols(best_table[i], i); |
511 | } |
512 | } |
513 | } |
514 | |
515 | /* start by placing the symbols that are actually used on the table */ |
516 | static void insert_real_symbols_in_table(void) |
517 | { |
518 | unsigned int i, j, c; |
519 | |
520 | memset(best_table, 0, sizeof(best_table)); |
521 | memset(best_table_len, 0, sizeof(best_table_len)); |
522 | |
523 | for (i = 0; i < table_cnt; i++) { |
524 | for (j = 0; j < table[i].len; j++) { |
525 | c = table[i].sym[j]; |
526 | best_table[c][0]=c; |
527 | best_table_len[c]=1; |
528 | } |
529 | } |
530 | } |
531 | |
532 | static void optimize_token_table(void) |
533 | { |
534 | build_initial_tok_table(); |
535 | |
536 | insert_real_symbols_in_table(); |
537 | |
538 | /* When valid symbol is not registered, exit to error */ |
539 | if (!table_cnt) { |
540 | fprintf(stderr, "No valid symbol.\n"); |
541 | exit(1); |
542 | } |
543 | |
544 | optimize_result(); |
545 | } |
546 | |
547 | /* guess for "linker script provide" symbol */ |
548 | static int may_be_linker_script_provide_symbol(const struct sym_entry *se) |
549 | { |
550 | const char *symbol = (char *)se->sym + 1; |
551 | int len = se->len - 1; |
552 | |
553 | if (len < 8) |
554 | return 0; |
555 | |
556 | if (symbol[0] != '_' || symbol[1] != '_') |
557 | return 0; |
558 | |
559 | /* __start_XXXXX */ |
560 | if (!memcmp(symbol + 2, "start_", 6)) |
561 | return 1; |
562 | |
563 | /* __stop_XXXXX */ |
564 | if (!memcmp(symbol + 2, "stop_", 5)) |
565 | return 1; |
566 | |
567 | /* __end_XXXXX */ |
568 | if (!memcmp(symbol + 2, "end_", 4)) |
569 | return 1; |
570 | |
571 | /* __XXXXX_start */ |
572 | if (!memcmp(symbol + len - 6, "_start", 6)) |
573 | return 1; |
574 | |
575 | /* __XXXXX_end */ |
576 | if (!memcmp(symbol + len - 4, "_end", 4)) |
577 | return 1; |
578 | |
579 | return 0; |
580 | } |
581 | |
582 | static int prefix_underscores_count(const char *str) |
583 | { |
584 | const char *tail = str; |
585 | |
586 | while (*tail == '_') |
587 | tail++; |
588 | |
589 | return tail - str; |
590 | } |
591 | |
592 | static int compare_symbols(const void *a, const void *b) |
593 | { |
594 | const struct sym_entry *sa; |
595 | const struct sym_entry *sb; |
596 | int wa, wb; |
597 | |
598 | sa = a; |
599 | sb = b; |
600 | |
601 | /* sort by address first */ |
602 | if (sa->addr > sb->addr) |
603 | return 1; |
604 | if (sa->addr < sb->addr) |
605 | return -1; |
606 | |
607 | /* sort by "weakness" type */ |
608 | wa = (sa->sym[0] == 'w') || (sa->sym[0] == 'W'); |
609 | wb = (sb->sym[0] == 'w') || (sb->sym[0] == 'W'); |
610 | if (wa != wb) |
611 | return wa - wb; |
612 | |
613 | /* sort by "linker script provide" type */ |
614 | wa = may_be_linker_script_provide_symbol(sa); |
615 | wb = may_be_linker_script_provide_symbol(sb); |
616 | if (wa != wb) |
617 | return wa - wb; |
618 | |
619 | /* sort by the number of prefix underscores */ |
620 | wa = prefix_underscores_count((const char *)sa->sym + 1); |
621 | wb = prefix_underscores_count((const char *)sb->sym + 1); |
622 | if (wa != wb) |
623 | return wa - wb; |
624 | |
625 | /* sort by initial order, so that other symbols are left undisturbed */ |
626 | return sa->start_pos - sb->start_pos; |
627 | } |
628 | |
629 | static void sort_symbols(void) |
630 | { |
631 | qsort(table, table_cnt, sizeof(struct sym_entry), compare_symbols); |
632 | } |
633 | |
634 | int main(int argc, char **argv) |
635 | { |
636 | if (argc >= 2) { |
637 | int i; |
638 | for (i = 1; i < argc; i++) { |
639 | if(strcmp(argv[i], "--all-symbols") == 0) |
640 | all_symbols = 1; |
641 | else if (strncmp(argv[i], "--symbol-prefix=", 16) == 0) { |
642 | char *p = &argv[i][16]; |
643 | /* skip quote */ |
644 | if ((*p == '"' && *(p+2) == '"') || (*p == '\'' && *(p+2) == '\'')) |
645 | p++; |
646 | symbol_prefix_char = *p; |
647 | } else |
648 | usage(); |
649 | } |
650 | } else if (argc != 1) |
651 | usage(); |
652 | |
653 | read_map(stdin); |
654 | sort_symbols(); |
655 | optimize_token_table(); |
656 | write_src(); |
657 | |
658 | return 0; |
659 | } |
660 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9