Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * kallsyms.c: in-kernel printing of symbolic oopses and stack traces. | |
3 | * | |
4 | * Rewritten and vastly simplified by Rusty Russell for in-kernel | |
5 | * module loader: | |
6 | * Copyright 2002 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation | |
7 | * | |
8 | * ChangeLog: | |
9 | * | |
10 | * (25/Aug/2004) Paulo Marques <pmarques@grupopie.com> | |
11 | * Changed the compression method from stem compression to "table lookup" | |
12 | * compression (see scripts/kallsyms.c for a more complete description) | |
13 | */ | |
14 | #include <linux/kallsyms.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/init.h> | |
17 | #include <linux/seq_file.h> | |
18 | #include <linux/fs.h> | |
19 | #include <linux/err.h> | |
20 | #include <linux/proc_fs.h> | |
4e57b681 | 21 | #include <linux/sched.h> /* for cond_resched */ |
1da177e4 | 22 | #include <linux/mm.h> |
07354a00 | 23 | #include <linux/ctype.h> |
5a0e3ad6 | 24 | #include <linux/slab.h> |
1da177e4 LT |
25 | |
26 | #include <asm/sections.h> | |
27 | ||
28 | #ifdef CONFIG_KALLSYMS_ALL | |
29 | #define all_var 1 | |
30 | #else | |
31 | #define all_var 0 | |
32 | #endif | |
33 | ||
ad6ccfad MK |
34 | /* |
35 | * These will be re-linked against their real values | |
36 | * during the second link stage. | |
37 | */ | |
2ea03891 SR |
38 | extern const unsigned long kallsyms_addresses[] __attribute__((weak)); |
39 | extern const u8 kallsyms_names[] __attribute__((weak)); | |
1da177e4 | 40 | |
ad6ccfad MK |
41 | /* |
42 | * Tell the compiler that the count isn't in the small data section if the arch | |
43 | * has one (eg: FRV). | |
9e6c1e63 DH |
44 | */ |
45 | extern const unsigned long kallsyms_num_syms | |
2ea03891 | 46 | __attribute__((weak, section(".rodata"))); |
9e6c1e63 | 47 | |
2ea03891 SR |
48 | extern const u8 kallsyms_token_table[] __attribute__((weak)); |
49 | extern const u16 kallsyms_token_index[] __attribute__((weak)); | |
1da177e4 | 50 | |
2ea03891 | 51 | extern const unsigned long kallsyms_markers[] __attribute__((weak)); |
1da177e4 LT |
52 | |
53 | static inline int is_kernel_inittext(unsigned long addr) | |
54 | { | |
55 | if (addr >= (unsigned long)_sinittext | |
56 | && addr <= (unsigned long)_einittext) | |
57 | return 1; | |
58 | return 0; | |
59 | } | |
60 | ||
61 | static inline int is_kernel_text(unsigned long addr) | |
62 | { | |
128e8db3 MF |
63 | if ((addr >= (unsigned long)_stext && addr <= (unsigned long)_etext) || |
64 | arch_is_kernel_text(addr)) | |
1da177e4 LT |
65 | return 1; |
66 | return in_gate_area_no_task(addr); | |
67 | } | |
68 | ||
69 | static inline int is_kernel(unsigned long addr) | |
70 | { | |
71 | if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end) | |
72 | return 1; | |
73 | return in_gate_area_no_task(addr); | |
74 | } | |
75 | ||
ffc50891 FBH |
76 | static int is_ksym_addr(unsigned long addr) |
77 | { | |
78 | if (all_var) | |
79 | return is_kernel(addr); | |
80 | ||
a3b81113 | 81 | return is_kernel_text(addr) || is_kernel_inittext(addr); |
ffc50891 FBH |
82 | } |
83 | ||
ad6ccfad MK |
84 | /* |
85 | * Expand a compressed symbol data into the resulting uncompressed string, | |
86 | * given the offset to where the symbol is in the compressed stream. | |
87 | */ | |
1da177e4 LT |
88 | static unsigned int kallsyms_expand_symbol(unsigned int off, char *result) |
89 | { | |
90 | int len, skipped_first = 0; | |
aad09470 | 91 | const u8 *tptr, *data; |
1da177e4 | 92 | |
ad6ccfad | 93 | /* Get the compressed symbol length from the first symbol byte. */ |
1da177e4 LT |
94 | data = &kallsyms_names[off]; |
95 | len = *data; | |
96 | data++; | |
97 | ||
ad6ccfad MK |
98 | /* |
99 | * Update the offset to return the offset for the next symbol on | |
100 | * the compressed stream. | |
101 | */ | |
1da177e4 LT |
102 | off += len + 1; |
103 | ||
ad6ccfad MK |
104 | /* |
105 | * For every byte on the compressed symbol data, copy the table | |
106 | * entry for that byte. | |
107 | */ | |
108 | while (len) { | |
109 | tptr = &kallsyms_token_table[kallsyms_token_index[*data]]; | |
1da177e4 LT |
110 | data++; |
111 | len--; | |
112 | ||
113 | while (*tptr) { | |
ad6ccfad | 114 | if (skipped_first) { |
1da177e4 LT |
115 | *result = *tptr; |
116 | result++; | |
117 | } else | |
118 | skipped_first = 1; | |
119 | tptr++; | |
120 | } | |
121 | } | |
122 | ||
123 | *result = '\0'; | |
124 | ||
ad6ccfad | 125 | /* Return to offset to the next symbol. */ |
1da177e4 LT |
126 | return off; |
127 | } | |
128 | ||
ad6ccfad MK |
129 | /* |
130 | * Get symbol type information. This is encoded as a single char at the | |
131 | * beginning of the symbol name. | |
132 | */ | |
1da177e4 LT |
133 | static char kallsyms_get_symbol_type(unsigned int off) |
134 | { | |
ad6ccfad MK |
135 | /* |
136 | * Get just the first code, look it up in the token table, | |
137 | * and return the first char from this token. | |
138 | */ | |
139 | return kallsyms_token_table[kallsyms_token_index[kallsyms_names[off + 1]]]; | |
1da177e4 LT |
140 | } |
141 | ||
142 | ||
ad6ccfad MK |
143 | /* |
144 | * Find the offset on the compressed stream given and index in the | |
145 | * kallsyms array. | |
146 | */ | |
1da177e4 LT |
147 | static unsigned int get_symbol_offset(unsigned long pos) |
148 | { | |
aad09470 | 149 | const u8 *name; |
1da177e4 LT |
150 | int i; |
151 | ||
ad6ccfad MK |
152 | /* |
153 | * Use the closest marker we have. We have markers every 256 positions, | |
154 | * so that should be close enough. | |
155 | */ | |
156 | name = &kallsyms_names[kallsyms_markers[pos >> 8]]; | |
1da177e4 | 157 | |
ad6ccfad MK |
158 | /* |
159 | * Sequentially scan all the symbols up to the point we're searching | |
160 | * for. Every symbol is stored in a [<len>][<len> bytes of data] format, | |
161 | * so we just need to add the len to the current pointer for every | |
162 | * symbol we wish to skip. | |
163 | */ | |
164 | for (i = 0; i < (pos & 0xFF); i++) | |
1da177e4 LT |
165 | name = name + (*name) + 1; |
166 | ||
167 | return name - kallsyms_names; | |
168 | } | |
169 | ||
170 | /* Lookup the address for this symbol. Returns 0 if not found. */ | |
171 | unsigned long kallsyms_lookup_name(const char *name) | |
172 | { | |
9281acea | 173 | char namebuf[KSYM_NAME_LEN]; |
1da177e4 LT |
174 | unsigned long i; |
175 | unsigned int off; | |
176 | ||
177 | for (i = 0, off = 0; i < kallsyms_num_syms; i++) { | |
178 | off = kallsyms_expand_symbol(off, namebuf); | |
179 | ||
180 | if (strcmp(namebuf, name) == 0) | |
181 | return kallsyms_addresses[i]; | |
182 | } | |
183 | return module_kallsyms_lookup_name(name); | |
184 | } | |
f60d24d2 | 185 | EXPORT_SYMBOL_GPL(kallsyms_lookup_name); |
1da177e4 | 186 | |
75a66614 AK |
187 | int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *, |
188 | unsigned long), | |
189 | void *data) | |
190 | { | |
191 | char namebuf[KSYM_NAME_LEN]; | |
192 | unsigned long i; | |
193 | unsigned int off; | |
194 | int ret; | |
195 | ||
196 | for (i = 0, off = 0; i < kallsyms_num_syms; i++) { | |
197 | off = kallsyms_expand_symbol(off, namebuf); | |
198 | ret = fn(data, namebuf, NULL, kallsyms_addresses[i]); | |
199 | if (ret != 0) | |
200 | return ret; | |
201 | } | |
202 | return module_kallsyms_on_each_symbol(fn, data); | |
203 | } | |
204 | EXPORT_SYMBOL_GPL(kallsyms_on_each_symbol); | |
205 | ||
ffc50891 FBH |
206 | static unsigned long get_symbol_pos(unsigned long addr, |
207 | unsigned long *symbolsize, | |
208 | unsigned long *offset) | |
209 | { | |
210 | unsigned long symbol_start = 0, symbol_end = 0; | |
211 | unsigned long i, low, high, mid; | |
212 | ||
2ea03891 SR |
213 | /* This kernel should never had been booted. */ |
214 | BUG_ON(!kallsyms_addresses); | |
215 | ||
ad6ccfad | 216 | /* Do a binary search on the sorted kallsyms_addresses array. */ |
ffc50891 FBH |
217 | low = 0; |
218 | high = kallsyms_num_syms; | |
219 | ||
220 | while (high - low > 1) { | |
2fc9c4e1 | 221 | mid = low + (high - low) / 2; |
ffc50891 FBH |
222 | if (kallsyms_addresses[mid] <= addr) |
223 | low = mid; | |
224 | else | |
225 | high = mid; | |
226 | } | |
227 | ||
228 | /* | |
ad6ccfad MK |
229 | * Search for the first aliased symbol. Aliased |
230 | * symbols are symbols with the same address. | |
ffc50891 FBH |
231 | */ |
232 | while (low && kallsyms_addresses[low-1] == kallsyms_addresses[low]) | |
233 | --low; | |
234 | ||
235 | symbol_start = kallsyms_addresses[low]; | |
236 | ||
ad6ccfad | 237 | /* Search for next non-aliased symbol. */ |
ffc50891 FBH |
238 | for (i = low + 1; i < kallsyms_num_syms; i++) { |
239 | if (kallsyms_addresses[i] > symbol_start) { | |
240 | symbol_end = kallsyms_addresses[i]; | |
241 | break; | |
242 | } | |
243 | } | |
244 | ||
ad6ccfad | 245 | /* If we found no next symbol, we use the end of the section. */ |
ffc50891 FBH |
246 | if (!symbol_end) { |
247 | if (is_kernel_inittext(addr)) | |
248 | symbol_end = (unsigned long)_einittext; | |
249 | else if (all_var) | |
250 | symbol_end = (unsigned long)_end; | |
251 | else | |
252 | symbol_end = (unsigned long)_etext; | |
253 | } | |
254 | ||
ffb45122 AD |
255 | if (symbolsize) |
256 | *symbolsize = symbol_end - symbol_start; | |
257 | if (offset) | |
258 | *offset = addr - symbol_start; | |
ffc50891 FBH |
259 | |
260 | return low; | |
261 | } | |
262 | ||
263 | /* | |
264 | * Lookup an address but don't bother to find any names. | |
265 | */ | |
266 | int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize, | |
267 | unsigned long *offset) | |
268 | { | |
6dd06c9f | 269 | char namebuf[KSYM_NAME_LEN]; |
ffc50891 FBH |
270 | if (is_ksym_addr(addr)) |
271 | return !!get_symbol_pos(addr, symbolsize, offset); | |
272 | ||
6dd06c9f | 273 | return !!module_address_lookup(addr, symbolsize, offset, NULL, namebuf); |
ffc50891 FBH |
274 | } |
275 | ||
1da177e4 LT |
276 | /* |
277 | * Lookup an address | |
ad6ccfad MK |
278 | * - modname is set to NULL if it's in the kernel. |
279 | * - We guarantee that the returned name is valid until we reschedule even if. | |
280 | * It resides in a module. | |
281 | * - We also guarantee that modname will be valid until rescheduled. | |
1da177e4 LT |
282 | */ |
283 | const char *kallsyms_lookup(unsigned long addr, | |
284 | unsigned long *symbolsize, | |
285 | unsigned long *offset, | |
286 | char **modname, char *namebuf) | |
287 | { | |
9281acea | 288 | namebuf[KSYM_NAME_LEN - 1] = 0; |
1da177e4 LT |
289 | namebuf[0] = 0; |
290 | ||
ffc50891 FBH |
291 | if (is_ksym_addr(addr)) { |
292 | unsigned long pos; | |
1da177e4 | 293 | |
ffc50891 | 294 | pos = get_symbol_pos(addr, symbolsize, offset); |
1da177e4 | 295 | /* Grab name */ |
ffc50891 | 296 | kallsyms_expand_symbol(get_symbol_offset(pos), namebuf); |
7a74fc49 KM |
297 | if (modname) |
298 | *modname = NULL; | |
1da177e4 LT |
299 | return namebuf; |
300 | } | |
301 | ||
ad6ccfad | 302 | /* See if it's in a module. */ |
6dd06c9f RR |
303 | return module_address_lookup(addr, symbolsize, offset, modname, |
304 | namebuf); | |
1da177e4 LT |
305 | } |
306 | ||
9d65cb4a AD |
307 | int lookup_symbol_name(unsigned long addr, char *symname) |
308 | { | |
309 | symname[0] = '\0'; | |
9281acea | 310 | symname[KSYM_NAME_LEN - 1] = '\0'; |
9d65cb4a AD |
311 | |
312 | if (is_ksym_addr(addr)) { | |
313 | unsigned long pos; | |
314 | ||
315 | pos = get_symbol_pos(addr, NULL, NULL); | |
316 | /* Grab name */ | |
317 | kallsyms_expand_symbol(get_symbol_offset(pos), symname); | |
318 | return 0; | |
319 | } | |
ad6ccfad | 320 | /* See if it's in a module. */ |
9d65cb4a AD |
321 | return lookup_module_symbol_name(addr, symname); |
322 | } | |
323 | ||
a5c43dae AD |
324 | int lookup_symbol_attrs(unsigned long addr, unsigned long *size, |
325 | unsigned long *offset, char *modname, char *name) | |
326 | { | |
327 | name[0] = '\0'; | |
9281acea | 328 | name[KSYM_NAME_LEN - 1] = '\0'; |
a5c43dae AD |
329 | |
330 | if (is_ksym_addr(addr)) { | |
331 | unsigned long pos; | |
332 | ||
333 | pos = get_symbol_pos(addr, size, offset); | |
334 | /* Grab name */ | |
335 | kallsyms_expand_symbol(get_symbol_offset(pos), name); | |
336 | modname[0] = '\0'; | |
337 | return 0; | |
338 | } | |
ad6ccfad | 339 | /* See if it's in a module. */ |
a5c43dae AD |
340 | return lookup_module_symbol_attrs(addr, size, offset, modname, name); |
341 | } | |
342 | ||
42e38083 RP |
343 | /* Look up a kernel symbol and return it in a text buffer. */ |
344 | int sprint_symbol(char *buffer, unsigned long address) | |
1da177e4 LT |
345 | { |
346 | char *modname; | |
347 | const char *name; | |
348 | unsigned long offset, size; | |
966c8c12 | 349 | int len; |
1da177e4 | 350 | |
966c8c12 | 351 | name = kallsyms_lookup(address, &size, &offset, &modname, buffer); |
1da177e4 | 352 | if (!name) |
42e38083 | 353 | return sprintf(buffer, "0x%lx", address); |
19769b76 | 354 | |
966c8c12 HD |
355 | if (name != buffer) |
356 | strcpy(buffer, name); | |
357 | len = strlen(buffer); | |
358 | buffer += len; | |
359 | ||
19769b76 | 360 | if (modname) |
966c8c12 HD |
361 | len += sprintf(buffer, "+%#lx/%#lx [%s]", |
362 | offset, size, modname); | |
19769b76 | 363 | else |
966c8c12 HD |
364 | len += sprintf(buffer, "+%#lx/%#lx", offset, size); |
365 | ||
366 | return len; | |
42e38083 | 367 | } |
ad6ccfad | 368 | EXPORT_SYMBOL_GPL(sprint_symbol); |
42e38083 RP |
369 | |
370 | /* Look up a kernel symbol and print it to the kernel messages. */ | |
371 | void __print_symbol(const char *fmt, unsigned long address) | |
372 | { | |
373 | char buffer[KSYM_SYMBOL_LEN]; | |
374 | ||
375 | sprint_symbol(buffer, address); | |
376 | ||
1da177e4 LT |
377 | printk(fmt, buffer); |
378 | } | |
ad6ccfad | 379 | EXPORT_SYMBOL(__print_symbol); |
1da177e4 LT |
380 | |
381 | /* To avoid using get_symbol_offset for every symbol, we carry prefix along. */ | |
ad6ccfad | 382 | struct kallsym_iter { |
1da177e4 | 383 | loff_t pos; |
1da177e4 | 384 | unsigned long value; |
ad6ccfad | 385 | unsigned int nameoff; /* If iterating in core kernel symbols. */ |
1da177e4 | 386 | char type; |
9281acea TH |
387 | char name[KSYM_NAME_LEN]; |
388 | char module_name[MODULE_NAME_LEN]; | |
ea07890a | 389 | int exported; |
1da177e4 LT |
390 | }; |
391 | ||
1da177e4 LT |
392 | static int get_ksymbol_mod(struct kallsym_iter *iter) |
393 | { | |
ea07890a AD |
394 | if (module_get_kallsym(iter->pos - kallsyms_num_syms, &iter->value, |
395 | &iter->type, iter->name, iter->module_name, | |
396 | &iter->exported) < 0) | |
1da177e4 | 397 | return 0; |
1da177e4 LT |
398 | return 1; |
399 | } | |
400 | ||
401 | /* Returns space to next name. */ | |
402 | static unsigned long get_ksymbol_core(struct kallsym_iter *iter) | |
403 | { | |
404 | unsigned off = iter->nameoff; | |
405 | ||
ea07890a | 406 | iter->module_name[0] = '\0'; |
1da177e4 LT |
407 | iter->value = kallsyms_addresses[iter->pos]; |
408 | ||
409 | iter->type = kallsyms_get_symbol_type(off); | |
410 | ||
411 | off = kallsyms_expand_symbol(off, iter->name); | |
412 | ||
413 | return off - iter->nameoff; | |
414 | } | |
415 | ||
416 | static void reset_iter(struct kallsym_iter *iter, loff_t new_pos) | |
417 | { | |
418 | iter->name[0] = '\0'; | |
419 | iter->nameoff = get_symbol_offset(new_pos); | |
420 | iter->pos = new_pos; | |
421 | } | |
422 | ||
423 | /* Returns false if pos at or past end of file. */ | |
424 | static int update_iter(struct kallsym_iter *iter, loff_t pos) | |
425 | { | |
426 | /* Module symbols can be accessed randomly. */ | |
427 | if (pos >= kallsyms_num_syms) { | |
428 | iter->pos = pos; | |
429 | return get_ksymbol_mod(iter); | |
430 | } | |
ad6ccfad | 431 | |
1da177e4 LT |
432 | /* If we're not on the desired position, reset to new position. */ |
433 | if (pos != iter->pos) | |
434 | reset_iter(iter, pos); | |
435 | ||
436 | iter->nameoff += get_ksymbol_core(iter); | |
437 | iter->pos++; | |
438 | ||
439 | return 1; | |
440 | } | |
441 | ||
442 | static void *s_next(struct seq_file *m, void *p, loff_t *pos) | |
443 | { | |
444 | (*pos)++; | |
445 | ||
446 | if (!update_iter(m->private, *pos)) | |
447 | return NULL; | |
448 | return p; | |
449 | } | |
450 | ||
451 | static void *s_start(struct seq_file *m, loff_t *pos) | |
452 | { | |
453 | if (!update_iter(m->private, *pos)) | |
454 | return NULL; | |
455 | return m->private; | |
456 | } | |
457 | ||
458 | static void s_stop(struct seq_file *m, void *p) | |
459 | { | |
460 | } | |
461 | ||
462 | static int s_show(struct seq_file *m, void *p) | |
463 | { | |
464 | struct kallsym_iter *iter = m->private; | |
465 | ||
ad6ccfad | 466 | /* Some debugging symbols have no name. Ignore them. */ |
1da177e4 LT |
467 | if (!iter->name[0]) |
468 | return 0; | |
469 | ||
ea07890a AD |
470 | if (iter->module_name[0]) { |
471 | char type; | |
472 | ||
ad6ccfad MK |
473 | /* |
474 | * Label it "global" if it is exported, | |
475 | * "local" if not exported. | |
476 | */ | |
ea07890a AD |
477 | type = iter->exported ? toupper(iter->type) : |
478 | tolower(iter->type); | |
1da177e4 | 479 | seq_printf(m, "%0*lx %c %s\t[%s]\n", |
ad6ccfad | 480 | (int)(2 * sizeof(void *)), |
ea07890a AD |
481 | iter->value, type, iter->name, iter->module_name); |
482 | } else | |
1da177e4 | 483 | seq_printf(m, "%0*lx %c %s\n", |
ad6ccfad | 484 | (int)(2 * sizeof(void *)), |
1da177e4 LT |
485 | iter->value, iter->type, iter->name); |
486 | return 0; | |
487 | } | |
488 | ||
15ad7cdc | 489 | static const struct seq_operations kallsyms_op = { |
1da177e4 LT |
490 | .start = s_start, |
491 | .next = s_next, | |
492 | .stop = s_stop, | |
493 | .show = s_show | |
494 | }; | |
495 | ||
496 | static int kallsyms_open(struct inode *inode, struct file *file) | |
497 | { | |
ad6ccfad MK |
498 | /* |
499 | * We keep iterator in m->private, since normal case is to | |
1da177e4 | 500 | * s_start from where we left off, so we avoid doing |
ad6ccfad MK |
501 | * using get_symbol_offset for every symbol. |
502 | */ | |
1da177e4 LT |
503 | struct kallsym_iter *iter; |
504 | int ret; | |
505 | ||
506 | iter = kmalloc(sizeof(*iter), GFP_KERNEL); | |
507 | if (!iter) | |
508 | return -ENOMEM; | |
509 | reset_iter(iter, 0); | |
510 | ||
511 | ret = seq_open(file, &kallsyms_op); | |
512 | if (ret == 0) | |
513 | ((struct seq_file *)file->private_data)->private = iter; | |
514 | else | |
515 | kfree(iter); | |
516 | return ret; | |
517 | } | |
518 | ||
15ad7cdc | 519 | static const struct file_operations kallsyms_operations = { |
1da177e4 LT |
520 | .open = kallsyms_open, |
521 | .read = seq_read, | |
522 | .llseek = seq_lseek, | |
5a0c6a0d | 523 | .release = seq_release_private, |
1da177e4 LT |
524 | }; |
525 | ||
526 | static int __init kallsyms_init(void) | |
527 | { | |
c33fff0a | 528 | proc_create("kallsyms", 0444, NULL, &kallsyms_operations); |
1da177e4 LT |
529 | return 0; |
530 | } | |
ad6ccfad | 531 | device_initcall(kallsyms_init); |