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 | } | |
1da177e4 | 184 | |
75a66614 AK |
185 | int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *, |
186 | unsigned long), | |
187 | void *data) | |
188 | { | |
189 | char namebuf[KSYM_NAME_LEN]; | |
190 | unsigned long i; | |
191 | unsigned int off; | |
192 | int ret; | |
193 | ||
194 | for (i = 0, off = 0; i < kallsyms_num_syms; i++) { | |
195 | off = kallsyms_expand_symbol(off, namebuf); | |
196 | ret = fn(data, namebuf, NULL, kallsyms_addresses[i]); | |
197 | if (ret != 0) | |
198 | return ret; | |
199 | } | |
200 | return module_kallsyms_on_each_symbol(fn, data); | |
201 | } | |
202 | EXPORT_SYMBOL_GPL(kallsyms_on_each_symbol); | |
203 | ||
ffc50891 FBH |
204 | static unsigned long get_symbol_pos(unsigned long addr, |
205 | unsigned long *symbolsize, | |
206 | unsigned long *offset) | |
207 | { | |
208 | unsigned long symbol_start = 0, symbol_end = 0; | |
209 | unsigned long i, low, high, mid; | |
210 | ||
2ea03891 SR |
211 | /* This kernel should never had been booted. */ |
212 | BUG_ON(!kallsyms_addresses); | |
213 | ||
ad6ccfad | 214 | /* Do a binary search on the sorted kallsyms_addresses array. */ |
ffc50891 FBH |
215 | low = 0; |
216 | high = kallsyms_num_syms; | |
217 | ||
218 | while (high - low > 1) { | |
2fc9c4e1 | 219 | mid = low + (high - low) / 2; |
ffc50891 FBH |
220 | if (kallsyms_addresses[mid] <= addr) |
221 | low = mid; | |
222 | else | |
223 | high = mid; | |
224 | } | |
225 | ||
226 | /* | |
ad6ccfad MK |
227 | * Search for the first aliased symbol. Aliased |
228 | * symbols are symbols with the same address. | |
ffc50891 FBH |
229 | */ |
230 | while (low && kallsyms_addresses[low-1] == kallsyms_addresses[low]) | |
231 | --low; | |
232 | ||
233 | symbol_start = kallsyms_addresses[low]; | |
234 | ||
ad6ccfad | 235 | /* Search for next non-aliased symbol. */ |
ffc50891 FBH |
236 | for (i = low + 1; i < kallsyms_num_syms; i++) { |
237 | if (kallsyms_addresses[i] > symbol_start) { | |
238 | symbol_end = kallsyms_addresses[i]; | |
239 | break; | |
240 | } | |
241 | } | |
242 | ||
ad6ccfad | 243 | /* If we found no next symbol, we use the end of the section. */ |
ffc50891 FBH |
244 | if (!symbol_end) { |
245 | if (is_kernel_inittext(addr)) | |
246 | symbol_end = (unsigned long)_einittext; | |
247 | else if (all_var) | |
248 | symbol_end = (unsigned long)_end; | |
249 | else | |
250 | symbol_end = (unsigned long)_etext; | |
251 | } | |
252 | ||
ffb45122 AD |
253 | if (symbolsize) |
254 | *symbolsize = symbol_end - symbol_start; | |
255 | if (offset) | |
256 | *offset = addr - symbol_start; | |
ffc50891 FBH |
257 | |
258 | return low; | |
259 | } | |
260 | ||
261 | /* | |
262 | * Lookup an address but don't bother to find any names. | |
263 | */ | |
264 | int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize, | |
265 | unsigned long *offset) | |
266 | { | |
6dd06c9f | 267 | char namebuf[KSYM_NAME_LEN]; |
ffc50891 FBH |
268 | if (is_ksym_addr(addr)) |
269 | return !!get_symbol_pos(addr, symbolsize, offset); | |
270 | ||
6dd06c9f | 271 | return !!module_address_lookup(addr, symbolsize, offset, NULL, namebuf); |
ffc50891 FBH |
272 | } |
273 | ||
1da177e4 LT |
274 | /* |
275 | * Lookup an address | |
ad6ccfad MK |
276 | * - modname is set to NULL if it's in the kernel. |
277 | * - We guarantee that the returned name is valid until we reschedule even if. | |
278 | * It resides in a module. | |
279 | * - We also guarantee that modname will be valid until rescheduled. | |
1da177e4 LT |
280 | */ |
281 | const char *kallsyms_lookup(unsigned long addr, | |
282 | unsigned long *symbolsize, | |
283 | unsigned long *offset, | |
284 | char **modname, char *namebuf) | |
285 | { | |
9281acea | 286 | namebuf[KSYM_NAME_LEN - 1] = 0; |
1da177e4 LT |
287 | namebuf[0] = 0; |
288 | ||
ffc50891 FBH |
289 | if (is_ksym_addr(addr)) { |
290 | unsigned long pos; | |
1da177e4 | 291 | |
ffc50891 | 292 | pos = get_symbol_pos(addr, symbolsize, offset); |
1da177e4 | 293 | /* Grab name */ |
ffc50891 | 294 | kallsyms_expand_symbol(get_symbol_offset(pos), namebuf); |
7a74fc49 KM |
295 | if (modname) |
296 | *modname = NULL; | |
1da177e4 LT |
297 | return namebuf; |
298 | } | |
299 | ||
ad6ccfad | 300 | /* See if it's in a module. */ |
6dd06c9f RR |
301 | return module_address_lookup(addr, symbolsize, offset, modname, |
302 | namebuf); | |
1da177e4 LT |
303 | } |
304 | ||
9d65cb4a AD |
305 | int lookup_symbol_name(unsigned long addr, char *symname) |
306 | { | |
307 | symname[0] = '\0'; | |
9281acea | 308 | symname[KSYM_NAME_LEN - 1] = '\0'; |
9d65cb4a AD |
309 | |
310 | if (is_ksym_addr(addr)) { | |
311 | unsigned long pos; | |
312 | ||
313 | pos = get_symbol_pos(addr, NULL, NULL); | |
314 | /* Grab name */ | |
315 | kallsyms_expand_symbol(get_symbol_offset(pos), symname); | |
316 | return 0; | |
317 | } | |
ad6ccfad | 318 | /* See if it's in a module. */ |
9d65cb4a AD |
319 | return lookup_module_symbol_name(addr, symname); |
320 | } | |
321 | ||
a5c43dae AD |
322 | int lookup_symbol_attrs(unsigned long addr, unsigned long *size, |
323 | unsigned long *offset, char *modname, char *name) | |
324 | { | |
325 | name[0] = '\0'; | |
9281acea | 326 | name[KSYM_NAME_LEN - 1] = '\0'; |
a5c43dae AD |
327 | |
328 | if (is_ksym_addr(addr)) { | |
329 | unsigned long pos; | |
330 | ||
331 | pos = get_symbol_pos(addr, size, offset); | |
332 | /* Grab name */ | |
333 | kallsyms_expand_symbol(get_symbol_offset(pos), name); | |
334 | modname[0] = '\0'; | |
335 | return 0; | |
336 | } | |
ad6ccfad | 337 | /* See if it's in a module. */ |
a5c43dae AD |
338 | return lookup_module_symbol_attrs(addr, size, offset, modname, name); |
339 | } | |
340 | ||
42e38083 RP |
341 | /* Look up a kernel symbol and return it in a text buffer. */ |
342 | int sprint_symbol(char *buffer, unsigned long address) | |
1da177e4 LT |
343 | { |
344 | char *modname; | |
345 | const char *name; | |
346 | unsigned long offset, size; | |
966c8c12 | 347 | int len; |
1da177e4 | 348 | |
966c8c12 | 349 | name = kallsyms_lookup(address, &size, &offset, &modname, buffer); |
1da177e4 | 350 | if (!name) |
42e38083 | 351 | return sprintf(buffer, "0x%lx", address); |
19769b76 | 352 | |
966c8c12 HD |
353 | if (name != buffer) |
354 | strcpy(buffer, name); | |
355 | len = strlen(buffer); | |
356 | buffer += len; | |
357 | ||
19769b76 | 358 | if (modname) |
966c8c12 HD |
359 | len += sprintf(buffer, "+%#lx/%#lx [%s]", |
360 | offset, size, modname); | |
19769b76 | 361 | else |
966c8c12 HD |
362 | len += sprintf(buffer, "+%#lx/%#lx", offset, size); |
363 | ||
364 | return len; | |
42e38083 | 365 | } |
ad6ccfad | 366 | EXPORT_SYMBOL_GPL(sprint_symbol); |
42e38083 RP |
367 | |
368 | /* Look up a kernel symbol and print it to the kernel messages. */ | |
369 | void __print_symbol(const char *fmt, unsigned long address) | |
370 | { | |
371 | char buffer[KSYM_SYMBOL_LEN]; | |
372 | ||
373 | sprint_symbol(buffer, address); | |
374 | ||
1da177e4 LT |
375 | printk(fmt, buffer); |
376 | } | |
ad6ccfad | 377 | EXPORT_SYMBOL(__print_symbol); |
1da177e4 LT |
378 | |
379 | /* To avoid using get_symbol_offset for every symbol, we carry prefix along. */ | |
ad6ccfad | 380 | struct kallsym_iter { |
1da177e4 | 381 | loff_t pos; |
1da177e4 | 382 | unsigned long value; |
ad6ccfad | 383 | unsigned int nameoff; /* If iterating in core kernel symbols. */ |
1da177e4 | 384 | char type; |
9281acea TH |
385 | char name[KSYM_NAME_LEN]; |
386 | char module_name[MODULE_NAME_LEN]; | |
ea07890a | 387 | int exported; |
1da177e4 LT |
388 | }; |
389 | ||
1da177e4 LT |
390 | static int get_ksymbol_mod(struct kallsym_iter *iter) |
391 | { | |
ea07890a AD |
392 | if (module_get_kallsym(iter->pos - kallsyms_num_syms, &iter->value, |
393 | &iter->type, iter->name, iter->module_name, | |
394 | &iter->exported) < 0) | |
1da177e4 | 395 | return 0; |
1da177e4 LT |
396 | return 1; |
397 | } | |
398 | ||
399 | /* Returns space to next name. */ | |
400 | static unsigned long get_ksymbol_core(struct kallsym_iter *iter) | |
401 | { | |
402 | unsigned off = iter->nameoff; | |
403 | ||
ea07890a | 404 | iter->module_name[0] = '\0'; |
1da177e4 LT |
405 | iter->value = kallsyms_addresses[iter->pos]; |
406 | ||
407 | iter->type = kallsyms_get_symbol_type(off); | |
408 | ||
409 | off = kallsyms_expand_symbol(off, iter->name); | |
410 | ||
411 | return off - iter->nameoff; | |
412 | } | |
413 | ||
414 | static void reset_iter(struct kallsym_iter *iter, loff_t new_pos) | |
415 | { | |
416 | iter->name[0] = '\0'; | |
417 | iter->nameoff = get_symbol_offset(new_pos); | |
418 | iter->pos = new_pos; | |
419 | } | |
420 | ||
421 | /* Returns false if pos at or past end of file. */ | |
422 | static int update_iter(struct kallsym_iter *iter, loff_t pos) | |
423 | { | |
424 | /* Module symbols can be accessed randomly. */ | |
425 | if (pos >= kallsyms_num_syms) { | |
426 | iter->pos = pos; | |
427 | return get_ksymbol_mod(iter); | |
428 | } | |
ad6ccfad | 429 | |
1da177e4 LT |
430 | /* If we're not on the desired position, reset to new position. */ |
431 | if (pos != iter->pos) | |
432 | reset_iter(iter, pos); | |
433 | ||
434 | iter->nameoff += get_ksymbol_core(iter); | |
435 | iter->pos++; | |
436 | ||
437 | return 1; | |
438 | } | |
439 | ||
440 | static void *s_next(struct seq_file *m, void *p, loff_t *pos) | |
441 | { | |
442 | (*pos)++; | |
443 | ||
444 | if (!update_iter(m->private, *pos)) | |
445 | return NULL; | |
446 | return p; | |
447 | } | |
448 | ||
449 | static void *s_start(struct seq_file *m, loff_t *pos) | |
450 | { | |
451 | if (!update_iter(m->private, *pos)) | |
452 | return NULL; | |
453 | return m->private; | |
454 | } | |
455 | ||
456 | static void s_stop(struct seq_file *m, void *p) | |
457 | { | |
458 | } | |
459 | ||
460 | static int s_show(struct seq_file *m, void *p) | |
461 | { | |
462 | struct kallsym_iter *iter = m->private; | |
463 | ||
ad6ccfad | 464 | /* Some debugging symbols have no name. Ignore them. */ |
1da177e4 LT |
465 | if (!iter->name[0]) |
466 | return 0; | |
467 | ||
ea07890a AD |
468 | if (iter->module_name[0]) { |
469 | char type; | |
470 | ||
ad6ccfad MK |
471 | /* |
472 | * Label it "global" if it is exported, | |
473 | * "local" if not exported. | |
474 | */ | |
ea07890a AD |
475 | type = iter->exported ? toupper(iter->type) : |
476 | tolower(iter->type); | |
1da177e4 | 477 | seq_printf(m, "%0*lx %c %s\t[%s]\n", |
ad6ccfad | 478 | (int)(2 * sizeof(void *)), |
ea07890a AD |
479 | iter->value, type, iter->name, iter->module_name); |
480 | } else | |
1da177e4 | 481 | seq_printf(m, "%0*lx %c %s\n", |
ad6ccfad | 482 | (int)(2 * sizeof(void *)), |
1da177e4 LT |
483 | iter->value, iter->type, iter->name); |
484 | return 0; | |
485 | } | |
486 | ||
15ad7cdc | 487 | static const struct seq_operations kallsyms_op = { |
1da177e4 LT |
488 | .start = s_start, |
489 | .next = s_next, | |
490 | .stop = s_stop, | |
491 | .show = s_show | |
492 | }; | |
493 | ||
494 | static int kallsyms_open(struct inode *inode, struct file *file) | |
495 | { | |
ad6ccfad MK |
496 | /* |
497 | * We keep iterator in m->private, since normal case is to | |
1da177e4 | 498 | * s_start from where we left off, so we avoid doing |
ad6ccfad MK |
499 | * using get_symbol_offset for every symbol. |
500 | */ | |
1da177e4 LT |
501 | struct kallsym_iter *iter; |
502 | int ret; | |
503 | ||
504 | iter = kmalloc(sizeof(*iter), GFP_KERNEL); | |
505 | if (!iter) | |
506 | return -ENOMEM; | |
507 | reset_iter(iter, 0); | |
508 | ||
509 | ret = seq_open(file, &kallsyms_op); | |
510 | if (ret == 0) | |
511 | ((struct seq_file *)file->private_data)->private = iter; | |
512 | else | |
513 | kfree(iter); | |
514 | return ret; | |
515 | } | |
516 | ||
15ad7cdc | 517 | static const struct file_operations kallsyms_operations = { |
1da177e4 LT |
518 | .open = kallsyms_open, |
519 | .read = seq_read, | |
520 | .llseek = seq_lseek, | |
5a0c6a0d | 521 | .release = seq_release_private, |
1da177e4 LT |
522 | }; |
523 | ||
524 | static int __init kallsyms_init(void) | |
525 | { | |
c33fff0a | 526 | proc_create("kallsyms", 0444, NULL, &kallsyms_operations); |
1da177e4 LT |
527 | return 0; |
528 | } | |
ad6ccfad | 529 | device_initcall(kallsyms_init); |