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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 | ||
9bb48247 JB |
33 | extern const unsigned long kallsyms_addresses[]; |
34 | extern const u8 kallsyms_names[]; | |
1da177e4 | 35 | |
9e6c1e63 DH |
36 | /* tell the compiler that the count isn't in the small data section if the arch |
37 | * has one (eg: FRV) | |
38 | */ | |
39 | extern const unsigned long kallsyms_num_syms | |
9bb48247 | 40 | __attribute__((__section__(".rodata"))); |
9e6c1e63 | 41 | |
9bb48247 JB |
42 | extern const u8 kallsyms_token_table[]; |
43 | extern const u16 kallsyms_token_index[]; | |
1da177e4 | 44 | |
9bb48247 | 45 | extern const unsigned long kallsyms_markers[]; |
1da177e4 LT |
46 | |
47 | static inline int is_kernel_inittext(unsigned long addr) | |
48 | { | |
49 | if (addr >= (unsigned long)_sinittext | |
50 | && addr <= (unsigned long)_einittext) | |
51 | return 1; | |
52 | return 0; | |
53 | } | |
54 | ||
55 | static inline int is_kernel_text(unsigned long addr) | |
56 | { | |
57 | if (addr >= (unsigned long)_stext && addr <= (unsigned long)_etext) | |
58 | return 1; | |
59 | return in_gate_area_no_task(addr); | |
60 | } | |
61 | ||
62 | static inline int is_kernel(unsigned long addr) | |
63 | { | |
64 | if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end) | |
65 | return 1; | |
66 | return in_gate_area_no_task(addr); | |
67 | } | |
68 | ||
ffc50891 FBH |
69 | static int is_ksym_addr(unsigned long addr) |
70 | { | |
71 | if (all_var) | |
72 | return is_kernel(addr); | |
73 | ||
a3b81113 | 74 | return is_kernel_text(addr) || is_kernel_inittext(addr); |
ffc50891 FBH |
75 | } |
76 | ||
1da177e4 LT |
77 | /* expand a compressed symbol data into the resulting uncompressed string, |
78 | given the offset to where the symbol is in the compressed stream */ | |
79 | static unsigned int kallsyms_expand_symbol(unsigned int off, char *result) | |
80 | { | |
81 | int len, skipped_first = 0; | |
aad09470 | 82 | const u8 *tptr, *data; |
1da177e4 LT |
83 | |
84 | /* get the compressed symbol length from the first symbol byte */ | |
85 | data = &kallsyms_names[off]; | |
86 | len = *data; | |
87 | data++; | |
88 | ||
89 | /* update the offset to return the offset for the next symbol on | |
90 | * the compressed stream */ | |
91 | off += len + 1; | |
92 | ||
93 | /* for every byte on the compressed symbol data, copy the table | |
94 | entry for that byte */ | |
95 | while(len) { | |
96 | tptr = &kallsyms_token_table[ kallsyms_token_index[*data] ]; | |
97 | data++; | |
98 | len--; | |
99 | ||
100 | while (*tptr) { | |
101 | if(skipped_first) { | |
102 | *result = *tptr; | |
103 | result++; | |
104 | } else | |
105 | skipped_first = 1; | |
106 | tptr++; | |
107 | } | |
108 | } | |
109 | ||
110 | *result = '\0'; | |
111 | ||
112 | /* return to offset to the next symbol */ | |
113 | return off; | |
114 | } | |
115 | ||
116 | /* get symbol type information. This is encoded as a single char at the | |
117 | * begining of the symbol name */ | |
118 | static char kallsyms_get_symbol_type(unsigned int off) | |
119 | { | |
120 | /* get just the first code, look it up in the token table, and return the | |
121 | * first char from this token */ | |
122 | return kallsyms_token_table[ kallsyms_token_index[ kallsyms_names[off+1] ] ]; | |
123 | } | |
124 | ||
125 | ||
126 | /* find the offset on the compressed stream given and index in the | |
127 | * kallsyms array */ | |
128 | static unsigned int get_symbol_offset(unsigned long pos) | |
129 | { | |
aad09470 | 130 | const u8 *name; |
1da177e4 LT |
131 | int i; |
132 | ||
133 | /* use the closest marker we have. We have markers every 256 positions, | |
134 | * so that should be close enough */ | |
135 | name = &kallsyms_names[ kallsyms_markers[pos>>8] ]; | |
136 | ||
137 | /* sequentially scan all the symbols up to the point we're searching for. | |
138 | * Every symbol is stored in a [<len>][<len> bytes of data] format, so we | |
139 | * just need to add the len to the current pointer for every symbol we | |
140 | * wish to skip */ | |
141 | for(i = 0; i < (pos&0xFF); i++) | |
142 | name = name + (*name) + 1; | |
143 | ||
144 | return name - kallsyms_names; | |
145 | } | |
146 | ||
147 | /* Lookup the address for this symbol. Returns 0 if not found. */ | |
148 | unsigned long kallsyms_lookup_name(const char *name) | |
149 | { | |
9281acea | 150 | char namebuf[KSYM_NAME_LEN]; |
1da177e4 LT |
151 | unsigned long i; |
152 | unsigned int off; | |
153 | ||
154 | for (i = 0, off = 0; i < kallsyms_num_syms; i++) { | |
155 | off = kallsyms_expand_symbol(off, namebuf); | |
156 | ||
157 | if (strcmp(namebuf, name) == 0) | |
158 | return kallsyms_addresses[i]; | |
159 | } | |
160 | return module_kallsyms_lookup_name(name); | |
161 | } | |
1da177e4 | 162 | |
ffc50891 FBH |
163 | static unsigned long get_symbol_pos(unsigned long addr, |
164 | unsigned long *symbolsize, | |
165 | unsigned long *offset) | |
166 | { | |
167 | unsigned long symbol_start = 0, symbol_end = 0; | |
168 | unsigned long i, low, high, mid; | |
169 | ||
ffc50891 FBH |
170 | /* do a binary search on the sorted kallsyms_addresses array */ |
171 | low = 0; | |
172 | high = kallsyms_num_syms; | |
173 | ||
174 | while (high - low > 1) { | |
2fc9c4e1 | 175 | mid = low + (high - low) / 2; |
ffc50891 FBH |
176 | if (kallsyms_addresses[mid] <= addr) |
177 | low = mid; | |
178 | else | |
179 | high = mid; | |
180 | } | |
181 | ||
182 | /* | |
183 | * search for the first aliased symbol. Aliased | |
184 | * symbols are symbols with the same address | |
185 | */ | |
186 | while (low && kallsyms_addresses[low-1] == kallsyms_addresses[low]) | |
187 | --low; | |
188 | ||
189 | symbol_start = kallsyms_addresses[low]; | |
190 | ||
191 | /* Search for next non-aliased symbol */ | |
192 | for (i = low + 1; i < kallsyms_num_syms; i++) { | |
193 | if (kallsyms_addresses[i] > symbol_start) { | |
194 | symbol_end = kallsyms_addresses[i]; | |
195 | break; | |
196 | } | |
197 | } | |
198 | ||
199 | /* if we found no next symbol, we use the end of the section */ | |
200 | if (!symbol_end) { | |
201 | if (is_kernel_inittext(addr)) | |
202 | symbol_end = (unsigned long)_einittext; | |
203 | else if (all_var) | |
204 | symbol_end = (unsigned long)_end; | |
205 | else | |
206 | symbol_end = (unsigned long)_etext; | |
207 | } | |
208 | ||
ffb45122 AD |
209 | if (symbolsize) |
210 | *symbolsize = symbol_end - symbol_start; | |
211 | if (offset) | |
212 | *offset = addr - symbol_start; | |
ffc50891 FBH |
213 | |
214 | return low; | |
215 | } | |
216 | ||
217 | /* | |
218 | * Lookup an address but don't bother to find any names. | |
219 | */ | |
220 | int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize, | |
221 | unsigned long *offset) | |
222 | { | |
6dd06c9f | 223 | char namebuf[KSYM_NAME_LEN]; |
ffc50891 FBH |
224 | if (is_ksym_addr(addr)) |
225 | return !!get_symbol_pos(addr, symbolsize, offset); | |
226 | ||
6dd06c9f | 227 | return !!module_address_lookup(addr, symbolsize, offset, NULL, namebuf); |
ffc50891 FBH |
228 | } |
229 | ||
1da177e4 LT |
230 | /* |
231 | * Lookup an address | |
232 | * - modname is set to NULL if it's in the kernel | |
233 | * - we guarantee that the returned name is valid until we reschedule even if | |
234 | * it resides in a module | |
235 | * - we also guarantee that modname will be valid until rescheduled | |
236 | */ | |
237 | const char *kallsyms_lookup(unsigned long addr, | |
238 | unsigned long *symbolsize, | |
239 | unsigned long *offset, | |
240 | char **modname, char *namebuf) | |
241 | { | |
9281acea | 242 | namebuf[KSYM_NAME_LEN - 1] = 0; |
1da177e4 LT |
243 | namebuf[0] = 0; |
244 | ||
ffc50891 FBH |
245 | if (is_ksym_addr(addr)) { |
246 | unsigned long pos; | |
1da177e4 | 247 | |
ffc50891 | 248 | pos = get_symbol_pos(addr, symbolsize, offset); |
1da177e4 | 249 | /* Grab name */ |
ffc50891 | 250 | kallsyms_expand_symbol(get_symbol_offset(pos), namebuf); |
7a74fc49 KM |
251 | if (modname) |
252 | *modname = NULL; | |
1da177e4 LT |
253 | return namebuf; |
254 | } | |
255 | ||
256 | /* see if it's in a module */ | |
6dd06c9f RR |
257 | return module_address_lookup(addr, symbolsize, offset, modname, |
258 | namebuf); | |
1da177e4 LT |
259 | } |
260 | ||
9d65cb4a AD |
261 | int lookup_symbol_name(unsigned long addr, char *symname) |
262 | { | |
263 | symname[0] = '\0'; | |
9281acea | 264 | symname[KSYM_NAME_LEN - 1] = '\0'; |
9d65cb4a AD |
265 | |
266 | if (is_ksym_addr(addr)) { | |
267 | unsigned long pos; | |
268 | ||
269 | pos = get_symbol_pos(addr, NULL, NULL); | |
270 | /* Grab name */ | |
271 | kallsyms_expand_symbol(get_symbol_offset(pos), symname); | |
272 | return 0; | |
273 | } | |
274 | /* see if it's in a module */ | |
275 | return lookup_module_symbol_name(addr, symname); | |
276 | } | |
277 | ||
a5c43dae AD |
278 | int lookup_symbol_attrs(unsigned long addr, unsigned long *size, |
279 | unsigned long *offset, char *modname, char *name) | |
280 | { | |
281 | name[0] = '\0'; | |
9281acea | 282 | name[KSYM_NAME_LEN - 1] = '\0'; |
a5c43dae AD |
283 | |
284 | if (is_ksym_addr(addr)) { | |
285 | unsigned long pos; | |
286 | ||
287 | pos = get_symbol_pos(addr, size, offset); | |
288 | /* Grab name */ | |
289 | kallsyms_expand_symbol(get_symbol_offset(pos), name); | |
290 | modname[0] = '\0'; | |
291 | return 0; | |
292 | } | |
293 | /* see if it's in a module */ | |
294 | return lookup_module_symbol_attrs(addr, size, offset, modname, name); | |
295 | } | |
296 | ||
42e38083 RP |
297 | /* Look up a kernel symbol and return it in a text buffer. */ |
298 | int sprint_symbol(char *buffer, unsigned long address) | |
1da177e4 LT |
299 | { |
300 | char *modname; | |
301 | const char *name; | |
302 | unsigned long offset, size; | |
966c8c12 | 303 | int len; |
1da177e4 | 304 | |
966c8c12 | 305 | name = kallsyms_lookup(address, &size, &offset, &modname, buffer); |
1da177e4 | 306 | if (!name) |
42e38083 | 307 | return sprintf(buffer, "0x%lx", address); |
19769b76 | 308 | |
966c8c12 HD |
309 | if (name != buffer) |
310 | strcpy(buffer, name); | |
311 | len = strlen(buffer); | |
312 | buffer += len; | |
313 | ||
19769b76 | 314 | if (modname) |
966c8c12 HD |
315 | len += sprintf(buffer, "+%#lx/%#lx [%s]", |
316 | offset, size, modname); | |
19769b76 | 317 | else |
966c8c12 HD |
318 | len += sprintf(buffer, "+%#lx/%#lx", offset, size); |
319 | ||
320 | return len; | |
42e38083 RP |
321 | } |
322 | ||
323 | /* Look up a kernel symbol and print it to the kernel messages. */ | |
324 | void __print_symbol(const char *fmt, unsigned long address) | |
325 | { | |
326 | char buffer[KSYM_SYMBOL_LEN]; | |
327 | ||
328 | sprint_symbol(buffer, address); | |
329 | ||
1da177e4 LT |
330 | printk(fmt, buffer); |
331 | } | |
332 | ||
333 | /* To avoid using get_symbol_offset for every symbol, we carry prefix along. */ | |
334 | struct kallsym_iter | |
335 | { | |
336 | loff_t pos; | |
1da177e4 LT |
337 | unsigned long value; |
338 | unsigned int nameoff; /* If iterating in core kernel symbols */ | |
339 | char type; | |
9281acea TH |
340 | char name[KSYM_NAME_LEN]; |
341 | char module_name[MODULE_NAME_LEN]; | |
ea07890a | 342 | int exported; |
1da177e4 LT |
343 | }; |
344 | ||
1da177e4 LT |
345 | static int get_ksymbol_mod(struct kallsym_iter *iter) |
346 | { | |
ea07890a AD |
347 | if (module_get_kallsym(iter->pos - kallsyms_num_syms, &iter->value, |
348 | &iter->type, iter->name, iter->module_name, | |
349 | &iter->exported) < 0) | |
1da177e4 | 350 | return 0; |
1da177e4 LT |
351 | return 1; |
352 | } | |
353 | ||
354 | /* Returns space to next name. */ | |
355 | static unsigned long get_ksymbol_core(struct kallsym_iter *iter) | |
356 | { | |
357 | unsigned off = iter->nameoff; | |
358 | ||
ea07890a | 359 | iter->module_name[0] = '\0'; |
1da177e4 LT |
360 | iter->value = kallsyms_addresses[iter->pos]; |
361 | ||
362 | iter->type = kallsyms_get_symbol_type(off); | |
363 | ||
364 | off = kallsyms_expand_symbol(off, iter->name); | |
365 | ||
366 | return off - iter->nameoff; | |
367 | } | |
368 | ||
369 | static void reset_iter(struct kallsym_iter *iter, loff_t new_pos) | |
370 | { | |
371 | iter->name[0] = '\0'; | |
372 | iter->nameoff = get_symbol_offset(new_pos); | |
373 | iter->pos = new_pos; | |
374 | } | |
375 | ||
376 | /* Returns false if pos at or past end of file. */ | |
377 | static int update_iter(struct kallsym_iter *iter, loff_t pos) | |
378 | { | |
379 | /* Module symbols can be accessed randomly. */ | |
380 | if (pos >= kallsyms_num_syms) { | |
381 | iter->pos = pos; | |
382 | return get_ksymbol_mod(iter); | |
383 | } | |
384 | ||
385 | /* If we're not on the desired position, reset to new position. */ | |
386 | if (pos != iter->pos) | |
387 | reset_iter(iter, pos); | |
388 | ||
389 | iter->nameoff += get_ksymbol_core(iter); | |
390 | iter->pos++; | |
391 | ||
392 | return 1; | |
393 | } | |
394 | ||
395 | static void *s_next(struct seq_file *m, void *p, loff_t *pos) | |
396 | { | |
397 | (*pos)++; | |
398 | ||
399 | if (!update_iter(m->private, *pos)) | |
400 | return NULL; | |
401 | return p; | |
402 | } | |
403 | ||
404 | static void *s_start(struct seq_file *m, loff_t *pos) | |
405 | { | |
406 | if (!update_iter(m->private, *pos)) | |
407 | return NULL; | |
408 | return m->private; | |
409 | } | |
410 | ||
411 | static void s_stop(struct seq_file *m, void *p) | |
412 | { | |
413 | } | |
414 | ||
415 | static int s_show(struct seq_file *m, void *p) | |
416 | { | |
417 | struct kallsym_iter *iter = m->private; | |
418 | ||
419 | /* Some debugging symbols have no name. Ignore them. */ | |
420 | if (!iter->name[0]) | |
421 | return 0; | |
422 | ||
ea07890a AD |
423 | if (iter->module_name[0]) { |
424 | char type; | |
425 | ||
426 | /* Label it "global" if it is exported, | |
427 | * "local" if not exported. */ | |
428 | type = iter->exported ? toupper(iter->type) : | |
429 | tolower(iter->type); | |
1da177e4 LT |
430 | seq_printf(m, "%0*lx %c %s\t[%s]\n", |
431 | (int)(2*sizeof(void*)), | |
ea07890a AD |
432 | iter->value, type, iter->name, iter->module_name); |
433 | } else | |
1da177e4 LT |
434 | seq_printf(m, "%0*lx %c %s\n", |
435 | (int)(2*sizeof(void*)), | |
436 | iter->value, iter->type, iter->name); | |
437 | return 0; | |
438 | } | |
439 | ||
15ad7cdc | 440 | static const struct seq_operations kallsyms_op = { |
1da177e4 LT |
441 | .start = s_start, |
442 | .next = s_next, | |
443 | .stop = s_stop, | |
444 | .show = s_show | |
445 | }; | |
446 | ||
447 | static int kallsyms_open(struct inode *inode, struct file *file) | |
448 | { | |
449 | /* We keep iterator in m->private, since normal case is to | |
450 | * s_start from where we left off, so we avoid doing | |
451 | * using get_symbol_offset for every symbol */ | |
452 | struct kallsym_iter *iter; | |
453 | int ret; | |
454 | ||
455 | iter = kmalloc(sizeof(*iter), GFP_KERNEL); | |
456 | if (!iter) | |
457 | return -ENOMEM; | |
458 | reset_iter(iter, 0); | |
459 | ||
460 | ret = seq_open(file, &kallsyms_op); | |
461 | if (ret == 0) | |
462 | ((struct seq_file *)file->private_data)->private = iter; | |
463 | else | |
464 | kfree(iter); | |
465 | return ret; | |
466 | } | |
467 | ||
15ad7cdc | 468 | static const struct file_operations kallsyms_operations = { |
1da177e4 LT |
469 | .open = kallsyms_open, |
470 | .read = seq_read, | |
471 | .llseek = seq_lseek, | |
5a0c6a0d | 472 | .release = seq_release_private, |
1da177e4 LT |
473 | }; |
474 | ||
475 | static int __init kallsyms_init(void) | |
476 | { | |
c33fff0a | 477 | proc_create("kallsyms", 0444, NULL, &kallsyms_operations); |
1da177e4 LT |
478 | return 0; |
479 | } | |
480 | __initcall(kallsyms_init); | |
481 | ||
482 | EXPORT_SYMBOL(__print_symbol); | |
42e38083 | 483 | EXPORT_SYMBOL_GPL(sprint_symbol); |