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