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