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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 | ||
33 | /* These will be re-linked against their real values during the second link stage */ | |
aad09470 | 34 | extern const unsigned long kallsyms_addresses[] __attribute__((weak)); |
aad09470 | 35 | extern const u8 kallsyms_names[] __attribute__((weak)); |
1da177e4 | 36 | |
9e6c1e63 DH |
37 | /* tell the compiler that the count isn't in the small data section if the arch |
38 | * has one (eg: FRV) | |
39 | */ | |
40 | extern const unsigned long kallsyms_num_syms | |
41 | __attribute__((weak, section(".rodata"))); | |
42 | ||
aad09470 JB |
43 | extern const u8 kallsyms_token_table[] __attribute__((weak)); |
44 | extern const u16 kallsyms_token_index[] __attribute__((weak)); | |
1da177e4 | 45 | |
aad09470 | 46 | extern const unsigned long kallsyms_markers[] __attribute__((weak)); |
1da177e4 LT |
47 | |
48 | static inline int is_kernel_inittext(unsigned long addr) | |
49 | { | |
50 | if (addr >= (unsigned long)_sinittext | |
51 | && addr <= (unsigned long)_einittext) | |
52 | return 1; | |
53 | return 0; | |
54 | } | |
55 | ||
075d6eb1 DW |
56 | static inline int is_kernel_extratext(unsigned long addr) |
57 | { | |
58 | if (addr >= (unsigned long)_sextratext | |
59 | && addr <= (unsigned long)_eextratext) | |
60 | return 1; | |
61 | return 0; | |
62 | } | |
63 | ||
1da177e4 LT |
64 | static inline int is_kernel_text(unsigned long addr) |
65 | { | |
66 | if (addr >= (unsigned long)_stext && addr <= (unsigned long)_etext) | |
67 | return 1; | |
68 | return in_gate_area_no_task(addr); | |
69 | } | |
70 | ||
71 | static inline int is_kernel(unsigned long addr) | |
72 | { | |
73 | if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end) | |
74 | return 1; | |
75 | return in_gate_area_no_task(addr); | |
76 | } | |
77 | ||
ffc50891 FBH |
78 | static int is_ksym_addr(unsigned long addr) |
79 | { | |
80 | if (all_var) | |
81 | return is_kernel(addr); | |
82 | ||
83 | return is_kernel_text(addr) || is_kernel_inittext(addr) || | |
84 | is_kernel_extratext(addr); | |
85 | } | |
86 | ||
1da177e4 LT |
87 | /* expand a compressed symbol data into the resulting uncompressed string, |
88 | given the offset to where the symbol is in the compressed stream */ | |
89 | static unsigned int kallsyms_expand_symbol(unsigned int off, char *result) | |
90 | { | |
91 | int len, skipped_first = 0; | |
aad09470 | 92 | const u8 *tptr, *data; |
1da177e4 LT |
93 | |
94 | /* get the compressed symbol length from the first symbol byte */ | |
95 | data = &kallsyms_names[off]; | |
96 | len = *data; | |
97 | data++; | |
98 | ||
99 | /* update the offset to return the offset for the next symbol on | |
100 | * the compressed stream */ | |
101 | off += len + 1; | |
102 | ||
103 | /* for every byte on the compressed symbol data, copy the table | |
104 | entry for that byte */ | |
105 | while(len) { | |
106 | tptr = &kallsyms_token_table[ kallsyms_token_index[*data] ]; | |
107 | data++; | |
108 | len--; | |
109 | ||
110 | while (*tptr) { | |
111 | if(skipped_first) { | |
112 | *result = *tptr; | |
113 | result++; | |
114 | } else | |
115 | skipped_first = 1; | |
116 | tptr++; | |
117 | } | |
118 | } | |
119 | ||
120 | *result = '\0'; | |
121 | ||
122 | /* return to offset to the next symbol */ | |
123 | return off; | |
124 | } | |
125 | ||
126 | /* get symbol type information. This is encoded as a single char at the | |
127 | * begining of the symbol name */ | |
128 | static char kallsyms_get_symbol_type(unsigned int off) | |
129 | { | |
130 | /* get just the first code, look it up in the token table, and return the | |
131 | * first char from this token */ | |
132 | return kallsyms_token_table[ kallsyms_token_index[ kallsyms_names[off+1] ] ]; | |
133 | } | |
134 | ||
135 | ||
136 | /* find the offset on the compressed stream given and index in the | |
137 | * kallsyms array */ | |
138 | static unsigned int get_symbol_offset(unsigned long pos) | |
139 | { | |
aad09470 | 140 | const u8 *name; |
1da177e4 LT |
141 | int i; |
142 | ||
143 | /* use the closest marker we have. We have markers every 256 positions, | |
144 | * so that should be close enough */ | |
145 | name = &kallsyms_names[ kallsyms_markers[pos>>8] ]; | |
146 | ||
147 | /* sequentially scan all the symbols up to the point we're searching for. | |
148 | * Every symbol is stored in a [<len>][<len> bytes of data] format, so we | |
149 | * just need to add the len to the current pointer for every symbol we | |
150 | * wish to skip */ | |
151 | for(i = 0; i < (pos&0xFF); i++) | |
152 | name = name + (*name) + 1; | |
153 | ||
154 | return name - kallsyms_names; | |
155 | } | |
156 | ||
157 | /* Lookup the address for this symbol. Returns 0 if not found. */ | |
158 | unsigned long kallsyms_lookup_name(const char *name) | |
159 | { | |
9281acea | 160 | char namebuf[KSYM_NAME_LEN]; |
1da177e4 LT |
161 | unsigned long i; |
162 | unsigned int off; | |
163 | ||
164 | for (i = 0, off = 0; i < kallsyms_num_syms; i++) { | |
165 | off = kallsyms_expand_symbol(off, namebuf); | |
166 | ||
167 | if (strcmp(namebuf, name) == 0) | |
168 | return kallsyms_addresses[i]; | |
169 | } | |
170 | return module_kallsyms_lookup_name(name); | |
171 | } | |
1da177e4 | 172 | |
ffc50891 FBH |
173 | static unsigned long get_symbol_pos(unsigned long addr, |
174 | unsigned long *symbolsize, | |
175 | unsigned long *offset) | |
176 | { | |
177 | unsigned long symbol_start = 0, symbol_end = 0; | |
178 | unsigned long i, low, high, mid; | |
179 | ||
180 | /* This kernel should never had been booted. */ | |
181 | BUG_ON(!kallsyms_addresses); | |
182 | ||
183 | /* do a binary search on the sorted kallsyms_addresses array */ | |
184 | low = 0; | |
185 | high = kallsyms_num_syms; | |
186 | ||
187 | while (high - low > 1) { | |
188 | mid = (low + high) / 2; | |
189 | if (kallsyms_addresses[mid] <= addr) | |
190 | low = mid; | |
191 | else | |
192 | high = mid; | |
193 | } | |
194 | ||
195 | /* | |
196 | * search for the first aliased symbol. Aliased | |
197 | * symbols are symbols with the same address | |
198 | */ | |
199 | while (low && kallsyms_addresses[low-1] == kallsyms_addresses[low]) | |
200 | --low; | |
201 | ||
202 | symbol_start = kallsyms_addresses[low]; | |
203 | ||
204 | /* Search for next non-aliased symbol */ | |
205 | for (i = low + 1; i < kallsyms_num_syms; i++) { | |
206 | if (kallsyms_addresses[i] > symbol_start) { | |
207 | symbol_end = kallsyms_addresses[i]; | |
208 | break; | |
209 | } | |
210 | } | |
211 | ||
212 | /* if we found no next symbol, we use the end of the section */ | |
213 | if (!symbol_end) { | |
214 | if (is_kernel_inittext(addr)) | |
215 | symbol_end = (unsigned long)_einittext; | |
216 | else if (all_var) | |
217 | symbol_end = (unsigned long)_end; | |
218 | else | |
219 | symbol_end = (unsigned long)_etext; | |
220 | } | |
221 | ||
ffb45122 AD |
222 | if (symbolsize) |
223 | *symbolsize = symbol_end - symbol_start; | |
224 | if (offset) | |
225 | *offset = addr - symbol_start; | |
ffc50891 FBH |
226 | |
227 | return low; | |
228 | } | |
229 | ||
230 | /* | |
231 | * Lookup an address but don't bother to find any names. | |
232 | */ | |
233 | int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize, | |
234 | unsigned long *offset) | |
235 | { | |
6dd06c9f | 236 | char namebuf[KSYM_NAME_LEN]; |
ffc50891 FBH |
237 | if (is_ksym_addr(addr)) |
238 | return !!get_symbol_pos(addr, symbolsize, offset); | |
239 | ||
6dd06c9f | 240 | return !!module_address_lookup(addr, symbolsize, offset, NULL, namebuf); |
ffc50891 FBH |
241 | } |
242 | ||
1da177e4 LT |
243 | /* |
244 | * Lookup an address | |
245 | * - modname is set to NULL if it's in the kernel | |
246 | * - we guarantee that the returned name is valid until we reschedule even if | |
247 | * it resides in a module | |
248 | * - we also guarantee that modname will be valid until rescheduled | |
249 | */ | |
250 | const char *kallsyms_lookup(unsigned long addr, | |
251 | unsigned long *symbolsize, | |
252 | unsigned long *offset, | |
253 | char **modname, char *namebuf) | |
254 | { | |
9281acea | 255 | namebuf[KSYM_NAME_LEN - 1] = 0; |
1da177e4 LT |
256 | namebuf[0] = 0; |
257 | ||
ffc50891 FBH |
258 | if (is_ksym_addr(addr)) { |
259 | unsigned long pos; | |
1da177e4 | 260 | |
ffc50891 | 261 | pos = get_symbol_pos(addr, symbolsize, offset); |
1da177e4 | 262 | /* Grab name */ |
ffc50891 | 263 | kallsyms_expand_symbol(get_symbol_offset(pos), namebuf); |
7a74fc49 KM |
264 | if (modname) |
265 | *modname = NULL; | |
1da177e4 LT |
266 | return namebuf; |
267 | } | |
268 | ||
269 | /* see if it's in a module */ | |
6dd06c9f RR |
270 | return module_address_lookup(addr, symbolsize, offset, modname, |
271 | namebuf); | |
1da177e4 LT |
272 | return NULL; |
273 | } | |
274 | ||
9d65cb4a AD |
275 | int lookup_symbol_name(unsigned long addr, char *symname) |
276 | { | |
277 | symname[0] = '\0'; | |
9281acea | 278 | symname[KSYM_NAME_LEN - 1] = '\0'; |
9d65cb4a AD |
279 | |
280 | if (is_ksym_addr(addr)) { | |
281 | unsigned long pos; | |
282 | ||
283 | pos = get_symbol_pos(addr, NULL, NULL); | |
284 | /* Grab name */ | |
285 | kallsyms_expand_symbol(get_symbol_offset(pos), symname); | |
286 | return 0; | |
287 | } | |
288 | /* see if it's in a module */ | |
289 | return lookup_module_symbol_name(addr, symname); | |
290 | } | |
291 | ||
a5c43dae AD |
292 | int lookup_symbol_attrs(unsigned long addr, unsigned long *size, |
293 | unsigned long *offset, char *modname, char *name) | |
294 | { | |
295 | name[0] = '\0'; | |
9281acea | 296 | name[KSYM_NAME_LEN - 1] = '\0'; |
a5c43dae AD |
297 | |
298 | if (is_ksym_addr(addr)) { | |
299 | unsigned long pos; | |
300 | ||
301 | pos = get_symbol_pos(addr, size, offset); | |
302 | /* Grab name */ | |
303 | kallsyms_expand_symbol(get_symbol_offset(pos), name); | |
304 | modname[0] = '\0'; | |
305 | return 0; | |
306 | } | |
307 | /* see if it's in a module */ | |
308 | return lookup_module_symbol_attrs(addr, size, offset, modname, name); | |
309 | } | |
310 | ||
42e38083 RP |
311 | /* Look up a kernel symbol and return it in a text buffer. */ |
312 | int sprint_symbol(char *buffer, unsigned long address) | |
1da177e4 LT |
313 | { |
314 | char *modname; | |
315 | const char *name; | |
316 | unsigned long offset, size; | |
9281acea | 317 | char namebuf[KSYM_NAME_LEN]; |
1da177e4 LT |
318 | |
319 | name = kallsyms_lookup(address, &size, &offset, &modname, namebuf); | |
1da177e4 | 320 | if (!name) |
42e38083 | 321 | return sprintf(buffer, "0x%lx", address); |
19769b76 AM |
322 | |
323 | if (modname) | |
324 | return sprintf(buffer, "%s+%#lx/%#lx [%s]", name, offset, | |
1da177e4 | 325 | size, modname); |
19769b76 AM |
326 | else |
327 | return sprintf(buffer, "%s+%#lx/%#lx", name, offset, size); | |
42e38083 RP |
328 | } |
329 | ||
330 | /* Look up a kernel symbol and print it to the kernel messages. */ | |
331 | void __print_symbol(const char *fmt, unsigned long address) | |
332 | { | |
333 | char buffer[KSYM_SYMBOL_LEN]; | |
334 | ||
335 | sprint_symbol(buffer, address); | |
336 | ||
1da177e4 LT |
337 | printk(fmt, buffer); |
338 | } | |
339 | ||
340 | /* To avoid using get_symbol_offset for every symbol, we carry prefix along. */ | |
341 | struct kallsym_iter | |
342 | { | |
343 | loff_t pos; | |
1da177e4 LT |
344 | unsigned long value; |
345 | unsigned int nameoff; /* If iterating in core kernel symbols */ | |
346 | char type; | |
9281acea TH |
347 | char name[KSYM_NAME_LEN]; |
348 | char module_name[MODULE_NAME_LEN]; | |
ea07890a | 349 | int exported; |
1da177e4 LT |
350 | }; |
351 | ||
1da177e4 LT |
352 | static int get_ksymbol_mod(struct kallsym_iter *iter) |
353 | { | |
ea07890a AD |
354 | if (module_get_kallsym(iter->pos - kallsyms_num_syms, &iter->value, |
355 | &iter->type, iter->name, iter->module_name, | |
356 | &iter->exported) < 0) | |
1da177e4 | 357 | return 0; |
1da177e4 LT |
358 | return 1; |
359 | } | |
360 | ||
361 | /* Returns space to next name. */ | |
362 | static unsigned long get_ksymbol_core(struct kallsym_iter *iter) | |
363 | { | |
364 | unsigned off = iter->nameoff; | |
365 | ||
ea07890a | 366 | iter->module_name[0] = '\0'; |
1da177e4 LT |
367 | iter->value = kallsyms_addresses[iter->pos]; |
368 | ||
369 | iter->type = kallsyms_get_symbol_type(off); | |
370 | ||
371 | off = kallsyms_expand_symbol(off, iter->name); | |
372 | ||
373 | return off - iter->nameoff; | |
374 | } | |
375 | ||
376 | static void reset_iter(struct kallsym_iter *iter, loff_t new_pos) | |
377 | { | |
378 | iter->name[0] = '\0'; | |
379 | iter->nameoff = get_symbol_offset(new_pos); | |
380 | iter->pos = new_pos; | |
381 | } | |
382 | ||
383 | /* Returns false if pos at or past end of file. */ | |
384 | static int update_iter(struct kallsym_iter *iter, loff_t pos) | |
385 | { | |
386 | /* Module symbols can be accessed randomly. */ | |
387 | if (pos >= kallsyms_num_syms) { | |
388 | iter->pos = pos; | |
389 | return get_ksymbol_mod(iter); | |
390 | } | |
391 | ||
392 | /* If we're not on the desired position, reset to new position. */ | |
393 | if (pos != iter->pos) | |
394 | reset_iter(iter, pos); | |
395 | ||
396 | iter->nameoff += get_ksymbol_core(iter); | |
397 | iter->pos++; | |
398 | ||
399 | return 1; | |
400 | } | |
401 | ||
402 | static void *s_next(struct seq_file *m, void *p, loff_t *pos) | |
403 | { | |
404 | (*pos)++; | |
405 | ||
406 | if (!update_iter(m->private, *pos)) | |
407 | return NULL; | |
408 | return p; | |
409 | } | |
410 | ||
411 | static void *s_start(struct seq_file *m, loff_t *pos) | |
412 | { | |
413 | if (!update_iter(m->private, *pos)) | |
414 | return NULL; | |
415 | return m->private; | |
416 | } | |
417 | ||
418 | static void s_stop(struct seq_file *m, void *p) | |
419 | { | |
420 | } | |
421 | ||
422 | static int s_show(struct seq_file *m, void *p) | |
423 | { | |
424 | struct kallsym_iter *iter = m->private; | |
425 | ||
426 | /* Some debugging symbols have no name. Ignore them. */ | |
427 | if (!iter->name[0]) | |
428 | return 0; | |
429 | ||
ea07890a AD |
430 | if (iter->module_name[0]) { |
431 | char type; | |
432 | ||
433 | /* Label it "global" if it is exported, | |
434 | * "local" if not exported. */ | |
435 | type = iter->exported ? toupper(iter->type) : | |
436 | tolower(iter->type); | |
1da177e4 LT |
437 | seq_printf(m, "%0*lx %c %s\t[%s]\n", |
438 | (int)(2*sizeof(void*)), | |
ea07890a AD |
439 | iter->value, type, iter->name, iter->module_name); |
440 | } else | |
1da177e4 LT |
441 | seq_printf(m, "%0*lx %c %s\n", |
442 | (int)(2*sizeof(void*)), | |
443 | iter->value, iter->type, iter->name); | |
444 | return 0; | |
445 | } | |
446 | ||
15ad7cdc | 447 | static const struct seq_operations kallsyms_op = { |
1da177e4 LT |
448 | .start = s_start, |
449 | .next = s_next, | |
450 | .stop = s_stop, | |
451 | .show = s_show | |
452 | }; | |
453 | ||
454 | static int kallsyms_open(struct inode *inode, struct file *file) | |
455 | { | |
456 | /* We keep iterator in m->private, since normal case is to | |
457 | * s_start from where we left off, so we avoid doing | |
458 | * using get_symbol_offset for every symbol */ | |
459 | struct kallsym_iter *iter; | |
460 | int ret; | |
461 | ||
462 | iter = kmalloc(sizeof(*iter), GFP_KERNEL); | |
463 | if (!iter) | |
464 | return -ENOMEM; | |
465 | reset_iter(iter, 0); | |
466 | ||
467 | ret = seq_open(file, &kallsyms_op); | |
468 | if (ret == 0) | |
469 | ((struct seq_file *)file->private_data)->private = iter; | |
470 | else | |
471 | kfree(iter); | |
472 | return ret; | |
473 | } | |
474 | ||
15ad7cdc | 475 | static const struct file_operations kallsyms_operations = { |
1da177e4 LT |
476 | .open = kallsyms_open, |
477 | .read = seq_read, | |
478 | .llseek = seq_lseek, | |
5a0c6a0d | 479 | .release = seq_release_private, |
1da177e4 LT |
480 | }; |
481 | ||
482 | static int __init kallsyms_init(void) | |
483 | { | |
484 | struct proc_dir_entry *entry; | |
485 | ||
486 | entry = create_proc_entry("kallsyms", 0444, NULL); | |
487 | if (entry) | |
488 | entry->proc_fops = &kallsyms_operations; | |
489 | return 0; | |
490 | } | |
491 | __initcall(kallsyms_init); | |
492 | ||
493 | EXPORT_SYMBOL(__print_symbol); | |
42e38083 | 494 | EXPORT_SYMBOL_GPL(sprint_symbol); |