ACPI: thinkpad-acpi: preserve radio state across shutdown
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / scripts / kallsyms.c
blob92758120a767d621355d030ddf2e7a831659d883
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 #define KSYM_NAME_LEN 128
28 struct sym_entry {
29 unsigned long long addr;
30 unsigned int len;
31 unsigned int start_pos;
32 unsigned char *sym;
35 static struct sym_entry *table;
36 static unsigned int table_size, table_cnt;
37 static unsigned long long _text, _stext, _etext, _sinittext, _einittext;
38 static int all_symbols = 0;
39 static char symbol_prefix_char = '\0';
41 int token_profit[0x10000];
43 /* the table that holds the result of the compression */
44 unsigned char best_table[256][2];
45 unsigned char best_table_len[256];
48 static void usage(void)
50 fprintf(stderr, "Usage: kallsyms [--all-symbols] [--symbol-prefix=<prefix char>] < in.map > out.S\n");
51 exit(1);
55 * This ignores the intensely annoying "mapping symbols" found
56 * in ARM ELF files: $a, $t and $d.
58 static inline int is_arm_mapping_symbol(const char *str)
60 return str[0] == '$' && strchr("atd", str[1])
61 && (str[2] == '\0' || str[2] == '.');
64 static int read_symbol(FILE *in, struct sym_entry *s)
66 char str[500];
67 char *sym, stype;
68 int rc;
70 rc = fscanf(in, "%llx %c %499s\n", &s->addr, &stype, str);
71 if (rc != 3) {
72 if (rc != EOF) {
73 /* skip line */
74 fgets(str, 500, in);
76 return -1;
79 sym = str;
80 /* skip prefix char */
81 if (symbol_prefix_char && str[0] == symbol_prefix_char)
82 sym++;
84 /* Ignore most absolute/undefined (?) symbols. */
85 if (strcmp(sym, "_text") == 0)
86 _text = s->addr;
87 else if (strcmp(sym, "_stext") == 0)
88 _stext = s->addr;
89 else if (strcmp(sym, "_etext") == 0)
90 _etext = s->addr;
91 else if (strcmp(sym, "_sinittext") == 0)
92 _sinittext = s->addr;
93 else if (strcmp(sym, "_einittext") == 0)
94 _einittext = s->addr;
95 else if (toupper(stype) == 'A')
97 /* Keep these useful absolute symbols */
98 if (strcmp(sym, "__kernel_syscall_via_break") &&
99 strcmp(sym, "__kernel_syscall_via_epc") &&
100 strcmp(sym, "__kernel_sigtramp") &&
101 strcmp(sym, "__gp"))
102 return -1;
105 else if (toupper(stype) == 'U' ||
106 is_arm_mapping_symbol(sym))
107 return -1;
108 /* exclude also MIPS ELF local symbols ($L123 instead of .L123) */
109 else if (str[0] == '$')
110 return -1;
111 /* exclude debugging symbols */
112 else if (stype == 'N')
113 return -1;
115 /* include the type field in the symbol name, so that it gets
116 * compressed together */
117 s->len = strlen(str) + 1;
118 s->sym = malloc(s->len + 1);
119 if (!s->sym) {
120 fprintf(stderr, "kallsyms failure: "
121 "unable to allocate required amount of memory\n");
122 exit(EXIT_FAILURE);
124 strcpy((char *)s->sym + 1, str);
125 s->sym[0] = stype;
127 return 0;
130 static int symbol_valid(struct sym_entry *s)
132 /* Symbols which vary between passes. Passes 1 and 2 must have
133 * identical symbol lists.
135 static char *special_symbols[] = {
136 /* Exclude linker generated symbols which vary between passes */
137 "_SDA_BASE_", /* ppc */
138 "_SDA2_BASE_", /* ppc */
139 NULL };
140 int i;
141 int offset = 1;
143 /* skip prefix char */
144 if (symbol_prefix_char && *(s->sym + 1) == symbol_prefix_char)
145 offset++;
147 /* if --all-symbols is not specified, then symbols outside the text
148 * and inittext sections are discarded */
149 if (!all_symbols) {
150 if ((s->addr < _stext || s->addr > _etext)
151 && (s->addr < _sinittext || s->addr > _einittext))
152 return 0;
153 /* Corner case. Discard any symbols with the same value as
154 * _etext _einittext; they can move between pass 1 and 2 when
155 * the kallsyms data are added. If these symbols move then
156 * they may get dropped in pass 2, which breaks the kallsyms
157 * rules.
159 if ((s->addr == _etext &&
160 strcmp((char *)s->sym + offset, "_etext")) ||
161 (s->addr == _einittext &&
162 strcmp((char *)s->sym + offset, "_einittext")))
163 return 0;
166 /* Exclude symbols which vary between passes. */
167 if (strstr((char *)s->sym + offset, "_compiled.") ||
168 strncmp((char*)s->sym + offset, "__compound_literal.", 19) == 0 ||
169 strncmp((char*)s->sym + offset, "__compound_literal$", 19) == 0)
170 return 0;
172 for (i = 0; special_symbols[i]; i++)
173 if( strcmp((char *)s->sym + offset, special_symbols[i]) == 0 )
174 return 0;
176 return 1;
179 static void read_map(FILE *in)
181 while (!feof(in)) {
182 if (table_cnt >= table_size) {
183 table_size += 10000;
184 table = realloc(table, sizeof(*table) * table_size);
185 if (!table) {
186 fprintf(stderr, "out of memory\n");
187 exit (1);
190 if (read_symbol(in, &table[table_cnt]) == 0) {
191 table[table_cnt].start_pos = table_cnt;
192 table_cnt++;
197 static void output_label(char *label)
199 if (symbol_prefix_char)
200 printf(".globl %c%s\n", symbol_prefix_char, label);
201 else
202 printf(".globl %s\n", label);
203 printf("\tALGN\n");
204 if (symbol_prefix_char)
205 printf("%c%s:\n", symbol_prefix_char, label);
206 else
207 printf("%s:\n", label);
210 /* uncompress a compressed symbol. When this function is called, the best table
211 * might still be compressed itself, so the function needs to be recursive */
212 static int expand_symbol(unsigned char *data, int len, char *result)
214 int c, rlen, total=0;
216 while (len) {
217 c = *data;
218 /* if the table holds a single char that is the same as the one
219 * we are looking for, then end the search */
220 if (best_table[c][0]==c && best_table_len[c]==1) {
221 *result++ = c;
222 total++;
223 } else {
224 /* if not, recurse and expand */
225 rlen = expand_symbol(best_table[c], best_table_len[c], result);
226 total += rlen;
227 result += rlen;
229 data++;
230 len--;
232 *result=0;
234 return total;
237 static void write_src(void)
239 unsigned int i, k, off;
240 unsigned int best_idx[256];
241 unsigned int *markers;
242 char buf[KSYM_NAME_LEN];
244 printf("#include <asm/types.h>\n");
245 printf("#if BITS_PER_LONG == 64\n");
246 printf("#define PTR .quad\n");
247 printf("#define ALGN .align 8\n");
248 printf("#else\n");
249 printf("#define PTR .long\n");
250 printf("#define ALGN .align 4\n");
251 printf("#endif\n");
253 printf("\t.section .rodata, \"a\"\n");
255 /* Provide proper symbols relocatability by their '_text'
256 * relativeness. The symbol names cannot be used to construct
257 * normal symbol references as the list of symbols contains
258 * symbols that are declared static and are private to their
259 * .o files. This prevents .tmp_kallsyms.o or any other
260 * object from referencing them.
262 output_label("kallsyms_addresses");
263 for (i = 0; i < table_cnt; i++) {
264 if (toupper(table[i].sym[0]) != 'A') {
265 if (_text <= table[i].addr)
266 printf("\tPTR\t_text + %#llx\n",
267 table[i].addr - _text);
268 else
269 printf("\tPTR\t_text - %#llx\n",
270 _text - table[i].addr);
271 } else {
272 printf("\tPTR\t%#llx\n", table[i].addr);
275 printf("\n");
277 output_label("kallsyms_num_syms");
278 printf("\tPTR\t%d\n", table_cnt);
279 printf("\n");
281 /* table of offset markers, that give the offset in the compressed stream
282 * every 256 symbols */
283 markers = malloc(sizeof(unsigned int) * ((table_cnt + 255) / 256));
284 if (!markers) {
285 fprintf(stderr, "kallsyms failure: "
286 "unable to allocate required memory\n");
287 exit(EXIT_FAILURE);
290 output_label("kallsyms_names");
291 off = 0;
292 for (i = 0; i < table_cnt; i++) {
293 if ((i & 0xFF) == 0)
294 markers[i >> 8] = off;
296 printf("\t.byte 0x%02x", table[i].len);
297 for (k = 0; k < table[i].len; k++)
298 printf(", 0x%02x", table[i].sym[k]);
299 printf("\n");
301 off += table[i].len + 1;
303 printf("\n");
305 output_label("kallsyms_markers");
306 for (i = 0; i < ((table_cnt + 255) >> 8); i++)
307 printf("\tPTR\t%d\n", markers[i]);
308 printf("\n");
310 free(markers);
312 output_label("kallsyms_token_table");
313 off = 0;
314 for (i = 0; i < 256; i++) {
315 best_idx[i] = off;
316 expand_symbol(best_table[i], best_table_len[i], buf);
317 printf("\t.asciz\t\"%s\"\n", buf);
318 off += strlen(buf) + 1;
320 printf("\n");
322 output_label("kallsyms_token_index");
323 for (i = 0; i < 256; i++)
324 printf("\t.short\t%d\n", best_idx[i]);
325 printf("\n");
329 /* table lookup compression functions */
331 /* count all the possible tokens in a symbol */
332 static void learn_symbol(unsigned char *symbol, int len)
334 int i;
336 for (i = 0; i < len - 1; i++)
337 token_profit[ symbol[i] + (symbol[i + 1] << 8) ]++;
340 /* decrease the count for all the possible tokens in a symbol */
341 static void forget_symbol(unsigned char *symbol, int len)
343 int i;
345 for (i = 0; i < len - 1; i++)
346 token_profit[ symbol[i] + (symbol[i + 1] << 8) ]--;
349 /* remove all the invalid symbols from the table and do the initial token count */
350 static void build_initial_tok_table(void)
352 unsigned int i, pos;
354 pos = 0;
355 for (i = 0; i < table_cnt; i++) {
356 if ( symbol_valid(&table[i]) ) {
357 if (pos != i)
358 table[pos] = table[i];
359 learn_symbol(table[pos].sym, table[pos].len);
360 pos++;
363 table_cnt = pos;
366 static void *find_token(unsigned char *str, int len, unsigned char *token)
368 int i;
370 for (i = 0; i < len - 1; i++) {
371 if (str[i] == token[0] && str[i+1] == token[1])
372 return &str[i];
374 return NULL;
377 /* replace a given token in all the valid symbols. Use the sampled symbols
378 * to update the counts */
379 static void compress_symbols(unsigned char *str, int idx)
381 unsigned int i, len, size;
382 unsigned char *p1, *p2;
384 for (i = 0; i < table_cnt; i++) {
386 len = table[i].len;
387 p1 = table[i].sym;
389 /* find the token on the symbol */
390 p2 = find_token(p1, len, str);
391 if (!p2) continue;
393 /* decrease the counts for this symbol's tokens */
394 forget_symbol(table[i].sym, len);
396 size = len;
398 do {
399 *p2 = idx;
400 p2++;
401 size -= (p2 - p1);
402 memmove(p2, p2 + 1, size);
403 p1 = p2;
404 len--;
406 if (size < 2) break;
408 /* find the token on the symbol */
409 p2 = find_token(p1, size, str);
411 } while (p2);
413 table[i].len = len;
415 /* increase the counts for this symbol's new tokens */
416 learn_symbol(table[i].sym, len);
420 /* search the token with the maximum profit */
421 static int find_best_token(void)
423 int i, best, bestprofit;
425 bestprofit=-10000;
426 best = 0;
428 for (i = 0; i < 0x10000; i++) {
429 if (token_profit[i] > bestprofit) {
430 best = i;
431 bestprofit = token_profit[i];
434 return best;
437 /* this is the core of the algorithm: calculate the "best" table */
438 static void optimize_result(void)
440 int i, best;
442 /* using the '\0' symbol last allows compress_symbols to use standard
443 * fast string functions */
444 for (i = 255; i >= 0; i--) {
446 /* if this table slot is empty (it is not used by an actual
447 * original char code */
448 if (!best_table_len[i]) {
450 /* find the token with the breates profit value */
451 best = find_best_token();
453 /* place it in the "best" table */
454 best_table_len[i] = 2;
455 best_table[i][0] = best & 0xFF;
456 best_table[i][1] = (best >> 8) & 0xFF;
458 /* replace this token in all the valid symbols */
459 compress_symbols(best_table[i], i);
464 /* start by placing the symbols that are actually used on the table */
465 static void insert_real_symbols_in_table(void)
467 unsigned int i, j, c;
469 memset(best_table, 0, sizeof(best_table));
470 memset(best_table_len, 0, sizeof(best_table_len));
472 for (i = 0; i < table_cnt; i++) {
473 for (j = 0; j < table[i].len; j++) {
474 c = table[i].sym[j];
475 best_table[c][0]=c;
476 best_table_len[c]=1;
481 static void optimize_token_table(void)
483 build_initial_tok_table();
485 insert_real_symbols_in_table();
487 /* When valid symbol is not registered, exit to error */
488 if (!table_cnt) {
489 fprintf(stderr, "No valid symbol.\n");
490 exit(1);
493 optimize_result();
496 static int compare_symbols(const void *a, const void *b)
498 const struct sym_entry *sa;
499 const struct sym_entry *sb;
500 int wa, wb;
502 sa = a;
503 sb = b;
505 /* sort by address first */
506 if (sa->addr > sb->addr)
507 return 1;
508 if (sa->addr < sb->addr)
509 return -1;
511 /* sort by "weakness" type */
512 wa = (sa->sym[0] == 'w') || (sa->sym[0] == 'W');
513 wb = (sb->sym[0] == 'w') || (sb->sym[0] == 'W');
514 if (wa != wb)
515 return wa - wb;
517 /* sort by initial order, so that other symbols are left undisturbed */
518 return sa->start_pos - sb->start_pos;
521 static void sort_symbols(void)
523 qsort(table, table_cnt, sizeof(struct sym_entry), compare_symbols);
526 int main(int argc, char **argv)
528 if (argc >= 2) {
529 int i;
530 for (i = 1; i < argc; i++) {
531 if(strcmp(argv[i], "--all-symbols") == 0)
532 all_symbols = 1;
533 else if (strncmp(argv[i], "--symbol-prefix=", 16) == 0) {
534 char *p = &argv[i][16];
535 /* skip quote */
536 if ((*p == '"' && *(p+2) == '"') || (*p == '\'' && *(p+2) == '\''))
537 p++;
538 symbol_prefix_char = *p;
539 } else
540 usage();
542 } else if (argc != 1)
543 usage();
545 read_map(stdin);
546 if (table_cnt) {
547 sort_symbols();
548 optimize_token_table();
550 write_src();
552 return 0;