percpu: handle __percpu notations in UP accessors
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / scripts / kallsyms.c
blobe3902fb39afd1f2c53f63c0cfa9aaa1273956a02
1 /* Generate assembler source containing symbol information
3 * Copyright 2002 by Kai Germaschewski
5 * This software may be used and distributed according to the terms
6 * of the GNU General Public License, incorporated herein by reference.
8 * Usage: nm -n vmlinux | scripts/kallsyms [--all-symbols] > symbols.S
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%.
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <ctype.h>
26 #ifndef ARRAY_SIZE
27 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof(arr[0]))
28 #endif
30 #define KSYM_NAME_LEN 128
32 struct sym_entry {
33 unsigned long long addr;
34 unsigned int len;
35 unsigned int start_pos;
36 unsigned char *sym;
39 struct text_range {
40 const char *stext, *etext;
41 unsigned long long start, end;
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 */
51 #define text_range_text (&text_ranges[0])
52 #define text_range_inittext (&text_ranges[1])
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';
59 int token_profit[0x10000];
61 /* the table that holds the result of the compression */
62 unsigned char best_table[256][2];
63 unsigned char best_table_len[256];
66 static void usage(void)
68 fprintf(stderr, "Usage: kallsyms [--all-symbols] [--symbol-prefix=<prefix char>] < in.map > out.S\n");
69 exit(1);
73 * This ignores the intensely annoying "mapping symbols" found
74 * in ARM ELF files: $a, $t and $d.
76 static inline int is_arm_mapping_symbol(const char *str)
78 return str[0] == '$' && strchr("atd", str[1])
79 && (str[2] == '\0' || str[2] == '.');
82 static int read_symbol_tr(const char *sym, unsigned long long addr)
84 size_t i;
85 struct text_range *tr;
87 for (i = 0; i < ARRAY_SIZE(text_ranges); ++i) {
88 tr = &text_ranges[i];
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;
99 return 1;
102 static int read_symbol(FILE *in, struct sym_entry *s)
104 char str[500];
105 char *sym, stype;
106 int rc;
108 rc = fscanf(in, "%llx %c %499s\n", &s->addr, &stype, str);
109 if (rc != 3) {
110 if (rc != EOF) {
111 /* skip line. sym is used as dummy to
112 * shut of "warn_unused_result" warning.
114 sym = fgets(str, 500, in);
116 return -1;
119 sym = str;
120 /* skip prefix char */
121 if (symbol_prefix_char && str[0] == symbol_prefix_char)
122 sym++;
124 /* Ignore most absolute/undefined (?) symbols. */
125 if (strcmp(sym, "_text") == 0)
126 _text = s->addr;
127 else if (read_symbol_tr(sym, s->addr) == 0)
128 /* nothing to do */;
129 else if (toupper(stype) == 'A')
131 /* Keep these useful absolute symbols */
132 if (strcmp(sym, "__kernel_syscall_via_break") &&
133 strcmp(sym, "__kernel_syscall_via_epc") &&
134 strcmp(sym, "__kernel_sigtramp") &&
135 strcmp(sym, "__gp"))
136 return -1;
139 else if (toupper(stype) == 'U' ||
140 is_arm_mapping_symbol(sym))
141 return -1;
142 /* exclude also MIPS ELF local symbols ($L123 instead of .L123) */
143 else if (str[0] == '$')
144 return -1;
145 /* exclude debugging symbols */
146 else if (stype == 'N')
147 return -1;
149 /* include the type field in the symbol name, so that it gets
150 * compressed together */
151 s->len = strlen(str) + 1;
152 s->sym = malloc(s->len + 1);
153 if (!s->sym) {
154 fprintf(stderr, "kallsyms failure: "
155 "unable to allocate required amount of memory\n");
156 exit(EXIT_FAILURE);
158 strcpy((char *)s->sym + 1, str);
159 s->sym[0] = stype;
161 return 0;
164 static int symbol_valid_tr(struct sym_entry *s)
166 size_t i;
167 struct text_range *tr;
169 for (i = 0; i < ARRAY_SIZE(text_ranges); ++i) {
170 tr = &text_ranges[i];
172 if (s->addr >= tr->start && s->addr <= tr->end)
173 return 1;
176 return 0;
179 static int symbol_valid(struct sym_entry *s)
181 /* Symbols which vary between passes. Passes 1 and 2 must have
182 * identical symbol lists. The kallsyms_* symbols below are only added
183 * after pass 1, they would be included in pass 2 when --all-symbols is
184 * specified so exclude them to get a stable symbol list.
186 static char *special_symbols[] = {
187 "kallsyms_addresses",
188 "kallsyms_num_syms",
189 "kallsyms_names",
190 "kallsyms_markers",
191 "kallsyms_token_table",
192 "kallsyms_token_index",
194 /* Exclude linker generated symbols which vary between passes */
195 "_SDA_BASE_", /* ppc */
196 "_SDA2_BASE_", /* ppc */
197 NULL };
198 int i;
199 int offset = 1;
201 /* skip prefix char */
202 if (symbol_prefix_char && *(s->sym + 1) == symbol_prefix_char)
203 offset++;
205 /* if --all-symbols is not specified, then symbols outside the text
206 * and inittext sections are discarded */
207 if (!all_symbols) {
208 if (symbol_valid_tr(s) == 0)
209 return 0;
210 /* Corner case. Discard any symbols with the same value as
211 * _etext _einittext; they can move between pass 1 and 2 when
212 * the kallsyms data are added. If these symbols move then
213 * they may get dropped in pass 2, which breaks the kallsyms
214 * rules.
216 if ((s->addr == text_range_text->end &&
217 strcmp((char *)s->sym + offset, text_range_text->etext)) ||
218 (s->addr == text_range_inittext->end &&
219 strcmp((char *)s->sym + offset, text_range_inittext->etext)))
220 return 0;
223 /* Exclude symbols which vary between passes. */
224 if (strstr((char *)s->sym + offset, "_compiled."))
225 return 0;
227 for (i = 0; special_symbols[i]; i++)
228 if( strcmp((char *)s->sym + offset, special_symbols[i]) == 0 )
229 return 0;
231 return 1;
234 static void read_map(FILE *in)
236 while (!feof(in)) {
237 if (table_cnt >= table_size) {
238 table_size += 10000;
239 table = realloc(table, sizeof(*table) * table_size);
240 if (!table) {
241 fprintf(stderr, "out of memory\n");
242 exit (1);
245 if (read_symbol(in, &table[table_cnt]) == 0) {
246 table[table_cnt].start_pos = table_cnt;
247 table_cnt++;
252 static void output_label(char *label)
254 if (symbol_prefix_char)
255 printf(".globl %c%s\n", symbol_prefix_char, label);
256 else
257 printf(".globl %s\n", label);
258 printf("\tALGN\n");
259 if (symbol_prefix_char)
260 printf("%c%s:\n", symbol_prefix_char, label);
261 else
262 printf("%s:\n", label);
265 /* uncompress a compressed symbol. When this function is called, the best table
266 * might still be compressed itself, so the function needs to be recursive */
267 static int expand_symbol(unsigned char *data, int len, char *result)
269 int c, rlen, total=0;
271 while (len) {
272 c = *data;
273 /* if the table holds a single char that is the same as the one
274 * we are looking for, then end the search */
275 if (best_table[c][0]==c && best_table_len[c]==1) {
276 *result++ = c;
277 total++;
278 } else {
279 /* if not, recurse and expand */
280 rlen = expand_symbol(best_table[c], best_table_len[c], result);
281 total += rlen;
282 result += rlen;
284 data++;
285 len--;
287 *result=0;
289 return total;
292 static void write_src(void)
294 unsigned int i, k, off;
295 unsigned int best_idx[256];
296 unsigned int *markers;
297 char buf[KSYM_NAME_LEN];
299 printf("#include <asm/types.h>\n");
300 printf("#if BITS_PER_LONG == 64\n");
301 printf("#define PTR .quad\n");
302 printf("#define ALGN .align 8\n");
303 printf("#else\n");
304 printf("#define PTR .long\n");
305 printf("#define ALGN .align 4\n");
306 printf("#endif\n");
308 printf("\t.section .rodata, \"a\"\n");
310 /* Provide proper symbols relocatability by their '_text'
311 * relativeness. The symbol names cannot be used to construct
312 * normal symbol references as the list of symbols contains
313 * symbols that are declared static and are private to their
314 * .o files. This prevents .tmp_kallsyms.o or any other
315 * object from referencing them.
317 output_label("kallsyms_addresses");
318 for (i = 0; i < table_cnt; i++) {
319 if (toupper(table[i].sym[0]) != 'A') {
320 if (_text <= table[i].addr)
321 printf("\tPTR\t_text + %#llx\n",
322 table[i].addr - _text);
323 else
324 printf("\tPTR\t_text - %#llx\n",
325 _text - table[i].addr);
326 } else {
327 printf("\tPTR\t%#llx\n", table[i].addr);
330 printf("\n");
332 output_label("kallsyms_num_syms");
333 printf("\tPTR\t%d\n", table_cnt);
334 printf("\n");
336 /* table of offset markers, that give the offset in the compressed stream
337 * every 256 symbols */
338 markers = malloc(sizeof(unsigned int) * ((table_cnt + 255) / 256));
339 if (!markers) {
340 fprintf(stderr, "kallsyms failure: "
341 "unable to allocate required memory\n");
342 exit(EXIT_FAILURE);
345 output_label("kallsyms_names");
346 off = 0;
347 for (i = 0; i < table_cnt; i++) {
348 if ((i & 0xFF) == 0)
349 markers[i >> 8] = off;
351 printf("\t.byte 0x%02x", table[i].len);
352 for (k = 0; k < table[i].len; k++)
353 printf(", 0x%02x", table[i].sym[k]);
354 printf("\n");
356 off += table[i].len + 1;
358 printf("\n");
360 output_label("kallsyms_markers");
361 for (i = 0; i < ((table_cnt + 255) >> 8); i++)
362 printf("\tPTR\t%d\n", markers[i]);
363 printf("\n");
365 free(markers);
367 output_label("kallsyms_token_table");
368 off = 0;
369 for (i = 0; i < 256; i++) {
370 best_idx[i] = off;
371 expand_symbol(best_table[i], best_table_len[i], buf);
372 printf("\t.asciz\t\"%s\"\n", buf);
373 off += strlen(buf) + 1;
375 printf("\n");
377 output_label("kallsyms_token_index");
378 for (i = 0; i < 256; i++)
379 printf("\t.short\t%d\n", best_idx[i]);
380 printf("\n");
384 /* table lookup compression functions */
386 /* count all the possible tokens in a symbol */
387 static void learn_symbol(unsigned char *symbol, int len)
389 int i;
391 for (i = 0; i < len - 1; i++)
392 token_profit[ symbol[i] + (symbol[i + 1] << 8) ]++;
395 /* decrease the count for all the possible tokens in a symbol */
396 static void forget_symbol(unsigned char *symbol, int len)
398 int i;
400 for (i = 0; i < len - 1; i++)
401 token_profit[ symbol[i] + (symbol[i + 1] << 8) ]--;
404 /* remove all the invalid symbols from the table and do the initial token count */
405 static void build_initial_tok_table(void)
407 unsigned int i, pos;
409 pos = 0;
410 for (i = 0; i < table_cnt; i++) {
411 if ( symbol_valid(&table[i]) ) {
412 if (pos != i)
413 table[pos] = table[i];
414 learn_symbol(table[pos].sym, table[pos].len);
415 pos++;
418 table_cnt = pos;
421 static void *find_token(unsigned char *str, int len, unsigned char *token)
423 int i;
425 for (i = 0; i < len - 1; i++) {
426 if (str[i] == token[0] && str[i+1] == token[1])
427 return &str[i];
429 return NULL;
432 /* replace a given token in all the valid symbols. Use the sampled symbols
433 * to update the counts */
434 static void compress_symbols(unsigned char *str, int idx)
436 unsigned int i, len, size;
437 unsigned char *p1, *p2;
439 for (i = 0; i < table_cnt; i++) {
441 len = table[i].len;
442 p1 = table[i].sym;
444 /* find the token on the symbol */
445 p2 = find_token(p1, len, str);
446 if (!p2) continue;
448 /* decrease the counts for this symbol's tokens */
449 forget_symbol(table[i].sym, len);
451 size = len;
453 do {
454 *p2 = idx;
455 p2++;
456 size -= (p2 - p1);
457 memmove(p2, p2 + 1, size);
458 p1 = p2;
459 len--;
461 if (size < 2) break;
463 /* find the token on the symbol */
464 p2 = find_token(p1, size, str);
466 } while (p2);
468 table[i].len = len;
470 /* increase the counts for this symbol's new tokens */
471 learn_symbol(table[i].sym, len);
475 /* search the token with the maximum profit */
476 static int find_best_token(void)
478 int i, best, bestprofit;
480 bestprofit=-10000;
481 best = 0;
483 for (i = 0; i < 0x10000; i++) {
484 if (token_profit[i] > bestprofit) {
485 best = i;
486 bestprofit = token_profit[i];
489 return best;
492 /* this is the core of the algorithm: calculate the "best" table */
493 static void optimize_result(void)
495 int i, best;
497 /* using the '\0' symbol last allows compress_symbols to use standard
498 * fast string functions */
499 for (i = 255; i >= 0; i--) {
501 /* if this table slot is empty (it is not used by an actual
502 * original char code */
503 if (!best_table_len[i]) {
505 /* find the token with the breates profit value */
506 best = find_best_token();
508 /* place it in the "best" table */
509 best_table_len[i] = 2;
510 best_table[i][0] = best & 0xFF;
511 best_table[i][1] = (best >> 8) & 0xFF;
513 /* replace this token in all the valid symbols */
514 compress_symbols(best_table[i], i);
519 /* start by placing the symbols that are actually used on the table */
520 static void insert_real_symbols_in_table(void)
522 unsigned int i, j, c;
524 memset(best_table, 0, sizeof(best_table));
525 memset(best_table_len, 0, sizeof(best_table_len));
527 for (i = 0; i < table_cnt; i++) {
528 for (j = 0; j < table[i].len; j++) {
529 c = table[i].sym[j];
530 best_table[c][0]=c;
531 best_table_len[c]=1;
536 static void optimize_token_table(void)
538 build_initial_tok_table();
540 insert_real_symbols_in_table();
542 /* When valid symbol is not registered, exit to error */
543 if (!table_cnt) {
544 fprintf(stderr, "No valid symbol.\n");
545 exit(1);
548 optimize_result();
551 /* guess for "linker script provide" symbol */
552 static int may_be_linker_script_provide_symbol(const struct sym_entry *se)
554 const char *symbol = (char *)se->sym + 1;
555 int len = se->len - 1;
557 if (len < 8)
558 return 0;
560 if (symbol[0] != '_' || symbol[1] != '_')
561 return 0;
563 /* __start_XXXXX */
564 if (!memcmp(symbol + 2, "start_", 6))
565 return 1;
567 /* __stop_XXXXX */
568 if (!memcmp(symbol + 2, "stop_", 5))
569 return 1;
571 /* __end_XXXXX */
572 if (!memcmp(symbol + 2, "end_", 4))
573 return 1;
575 /* __XXXXX_start */
576 if (!memcmp(symbol + len - 6, "_start", 6))
577 return 1;
579 /* __XXXXX_end */
580 if (!memcmp(symbol + len - 4, "_end", 4))
581 return 1;
583 return 0;
586 static int prefix_underscores_count(const char *str)
588 const char *tail = str;
590 while (*tail == '_')
591 tail++;
593 return tail - str;
596 static int compare_symbols(const void *a, const void *b)
598 const struct sym_entry *sa;
599 const struct sym_entry *sb;
600 int wa, wb;
602 sa = a;
603 sb = b;
605 /* sort by address first */
606 if (sa->addr > sb->addr)
607 return 1;
608 if (sa->addr < sb->addr)
609 return -1;
611 /* sort by "weakness" type */
612 wa = (sa->sym[0] == 'w') || (sa->sym[0] == 'W');
613 wb = (sb->sym[0] == 'w') || (sb->sym[0] == 'W');
614 if (wa != wb)
615 return wa - wb;
617 /* sort by "linker script provide" type */
618 wa = may_be_linker_script_provide_symbol(sa);
619 wb = may_be_linker_script_provide_symbol(sb);
620 if (wa != wb)
621 return wa - wb;
623 /* sort by the number of prefix underscores */
624 wa = prefix_underscores_count((const char *)sa->sym + 1);
625 wb = prefix_underscores_count((const char *)sb->sym + 1);
626 if (wa != wb)
627 return wa - wb;
629 /* sort by initial order, so that other symbols are left undisturbed */
630 return sa->start_pos - sb->start_pos;
633 static void sort_symbols(void)
635 qsort(table, table_cnt, sizeof(struct sym_entry), compare_symbols);
638 int main(int argc, char **argv)
640 if (argc >= 2) {
641 int i;
642 for (i = 1; i < argc; i++) {
643 if(strcmp(argv[i], "--all-symbols") == 0)
644 all_symbols = 1;
645 else if (strncmp(argv[i], "--symbol-prefix=", 16) == 0) {
646 char *p = &argv[i][16];
647 /* skip quote */
648 if ((*p == '"' && *(p+2) == '"') || (*p == '\'' && *(p+2) == '\''))
649 p++;
650 symbol_prefix_char = *p;
651 } else
652 usage();
654 } else if (argc != 1)
655 usage();
657 read_map(stdin);
658 sort_symbols();
659 optimize_token_table();
660 write_src();
662 return 0;