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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/kdb.h> | |
20 | #include <linux/err.h> | |
21 | #include <linux/proc_fs.h> | |
22 | #include <linux/sched.h> /* for cond_resched */ | |
23 | #include <linux/mm.h> | |
24 | #include <linux/ctype.h> | |
25 | #include <linux/slab.h> | |
26 | #include <linux/filter.h> | |
27 | #include <linux/compiler.h> | |
28 | ||
29 | #include <asm/sections.h> | |
30 | ||
31 | #ifdef CONFIG_KALLSYMS_ALL | |
32 | #define all_var 1 | |
33 | #else | |
34 | #define all_var 0 | |
35 | #endif | |
36 | ||
37 | /* | |
38 | * These will be re-linked against their real values | |
39 | * during the second link stage. | |
40 | */ | |
41 | extern const unsigned long kallsyms_addresses[] __weak; | |
42 | extern const int kallsyms_offsets[] __weak; | |
43 | extern const u8 kallsyms_names[] __weak; | |
44 | ||
45 | /* | |
46 | * Tell the compiler that the count isn't in the small data section if the arch | |
47 | * has one (eg: FRV). | |
48 | */ | |
49 | extern const unsigned long kallsyms_num_syms | |
50 | __attribute__((weak, section(".rodata"))); | |
51 | ||
52 | extern const unsigned long kallsyms_relative_base | |
53 | __attribute__((weak, section(".rodata"))); | |
54 | ||
55 | extern const u8 kallsyms_token_table[] __weak; | |
56 | extern const u16 kallsyms_token_index[] __weak; | |
57 | ||
58 | extern const unsigned long kallsyms_markers[] __weak; | |
59 | ||
60 | static inline int is_kernel_inittext(unsigned long addr) | |
61 | { | |
62 | if (addr >= (unsigned long)_sinittext | |
63 | && addr <= (unsigned long)_einittext) | |
64 | return 1; | |
65 | return 0; | |
66 | } | |
67 | ||
68 | static inline int is_kernel_text(unsigned long addr) | |
69 | { | |
70 | if ((addr >= (unsigned long)_stext && addr <= (unsigned long)_etext) || | |
71 | arch_is_kernel_text(addr)) | |
72 | return 1; | |
73 | return in_gate_area_no_mm(addr); | |
74 | } | |
75 | ||
76 | static inline int is_kernel(unsigned long addr) | |
77 | { | |
78 | if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end) | |
79 | return 1; | |
80 | return in_gate_area_no_mm(addr); | |
81 | } | |
82 | ||
83 | static int is_ksym_addr(unsigned long addr) | |
84 | { | |
85 | if (all_var) | |
86 | return is_kernel(addr); | |
87 | ||
88 | return is_kernel_text(addr) || is_kernel_inittext(addr); | |
89 | } | |
90 | ||
91 | /* | |
92 | * Expand a compressed symbol data into the resulting uncompressed string, | |
93 | * if uncompressed string is too long (>= maxlen), it will be truncated, | |
94 | * given the offset to where the symbol is in the compressed stream. | |
95 | */ | |
96 | static unsigned int kallsyms_expand_symbol(unsigned int off, | |
97 | char *result, size_t maxlen) | |
98 | { | |
99 | int len, skipped_first = 0; | |
100 | const u8 *tptr, *data; | |
101 | ||
102 | /* Get the compressed symbol length from the first symbol byte. */ | |
103 | data = &kallsyms_names[off]; | |
104 | len = *data; | |
105 | data++; | |
106 | ||
107 | /* | |
108 | * Update the offset to return the offset for the next symbol on | |
109 | * the compressed stream. | |
110 | */ | |
111 | off += len + 1; | |
112 | ||
113 | /* | |
114 | * For every byte on the compressed symbol data, copy the table | |
115 | * entry for that byte. | |
116 | */ | |
117 | while (len) { | |
118 | tptr = &kallsyms_token_table[kallsyms_token_index[*data]]; | |
119 | data++; | |
120 | len--; | |
121 | ||
122 | while (*tptr) { | |
123 | if (skipped_first) { | |
124 | if (maxlen <= 1) | |
125 | goto tail; | |
126 | *result = *tptr; | |
127 | result++; | |
128 | maxlen--; | |
129 | } else | |
130 | skipped_first = 1; | |
131 | tptr++; | |
132 | } | |
133 | } | |
134 | ||
135 | tail: | |
136 | if (maxlen) | |
137 | *result = '\0'; | |
138 | ||
139 | /* Return to offset to the next symbol. */ | |
140 | return off; | |
141 | } | |
142 | ||
143 | /* | |
144 | * Get symbol type information. This is encoded as a single char at the | |
145 | * beginning of the symbol name. | |
146 | */ | |
147 | static char kallsyms_get_symbol_type(unsigned int off) | |
148 | { | |
149 | /* | |
150 | * Get just the first code, look it up in the token table, | |
151 | * and return the first char from this token. | |
152 | */ | |
153 | return kallsyms_token_table[kallsyms_token_index[kallsyms_names[off + 1]]]; | |
154 | } | |
155 | ||
156 | ||
157 | /* | |
158 | * Find the offset on the compressed stream given and index in the | |
159 | * kallsyms array. | |
160 | */ | |
161 | static unsigned int get_symbol_offset(unsigned long pos) | |
162 | { | |
163 | const u8 *name; | |
164 | int i; | |
165 | ||
166 | /* | |
167 | * Use the closest marker we have. We have markers every 256 positions, | |
168 | * so that should be close enough. | |
169 | */ | |
170 | name = &kallsyms_names[kallsyms_markers[pos >> 8]]; | |
171 | ||
172 | /* | |
173 | * Sequentially scan all the symbols up to the point we're searching | |
174 | * for. Every symbol is stored in a [<len>][<len> bytes of data] format, | |
175 | * so we just need to add the len to the current pointer for every | |
176 | * symbol we wish to skip. | |
177 | */ | |
178 | for (i = 0; i < (pos & 0xFF); i++) | |
179 | name = name + (*name) + 1; | |
180 | ||
181 | return name - kallsyms_names; | |
182 | } | |
183 | ||
184 | static unsigned long kallsyms_sym_address(int idx) | |
185 | { | |
186 | if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE)) | |
187 | return kallsyms_addresses[idx]; | |
188 | ||
189 | /* values are unsigned offsets if --absolute-percpu is not in effect */ | |
190 | if (!IS_ENABLED(CONFIG_KALLSYMS_ABSOLUTE_PERCPU)) | |
191 | return kallsyms_relative_base + (u32)kallsyms_offsets[idx]; | |
192 | ||
193 | /* ...otherwise, positive offsets are absolute values */ | |
194 | if (kallsyms_offsets[idx] >= 0) | |
195 | return kallsyms_offsets[idx]; | |
196 | ||
197 | /* ...and negative offsets are relative to kallsyms_relative_base - 1 */ | |
198 | return kallsyms_relative_base - 1 - kallsyms_offsets[idx]; | |
199 | } | |
200 | ||
201 | /* Lookup the address for this symbol. Returns 0 if not found. */ | |
202 | unsigned long kallsyms_lookup_name(const char *name) | |
203 | { | |
204 | char namebuf[KSYM_NAME_LEN]; | |
205 | unsigned long i; | |
206 | unsigned int off; | |
207 | ||
208 | for (i = 0, off = 0; i < kallsyms_num_syms; i++) { | |
209 | off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf)); | |
210 | ||
211 | if (strcmp(namebuf, name) == 0) | |
212 | return kallsyms_sym_address(i); | |
213 | } | |
214 | return module_kallsyms_lookup_name(name); | |
215 | } | |
216 | EXPORT_SYMBOL_GPL(kallsyms_lookup_name); | |
217 | ||
218 | int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *, | |
219 | unsigned long), | |
220 | void *data) | |
221 | { | |
222 | char namebuf[KSYM_NAME_LEN]; | |
223 | unsigned long i; | |
224 | unsigned int off; | |
225 | int ret; | |
226 | ||
227 | for (i = 0, off = 0; i < kallsyms_num_syms; i++) { | |
228 | off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf)); | |
229 | ret = fn(data, namebuf, NULL, kallsyms_sym_address(i)); | |
230 | if (ret != 0) | |
231 | return ret; | |
232 | } | |
233 | return module_kallsyms_on_each_symbol(fn, data); | |
234 | } | |
235 | EXPORT_SYMBOL_GPL(kallsyms_on_each_symbol); | |
236 | ||
237 | static unsigned long get_symbol_pos(unsigned long addr, | |
238 | unsigned long *symbolsize, | |
239 | unsigned long *offset) | |
240 | { | |
241 | unsigned long symbol_start = 0, symbol_end = 0; | |
242 | unsigned long i, low, high, mid; | |
243 | ||
244 | /* This kernel should never had been booted. */ | |
245 | if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE)) | |
246 | BUG_ON(!kallsyms_addresses); | |
247 | else | |
248 | BUG_ON(!kallsyms_offsets); | |
249 | ||
250 | /* Do a binary search on the sorted kallsyms_addresses array. */ | |
251 | low = 0; | |
252 | high = kallsyms_num_syms; | |
253 | ||
254 | while (high - low > 1) { | |
255 | mid = low + (high - low) / 2; | |
256 | if (kallsyms_sym_address(mid) <= addr) | |
257 | low = mid; | |
258 | else | |
259 | high = mid; | |
260 | } | |
261 | ||
262 | /* | |
263 | * Search for the first aliased symbol. Aliased | |
264 | * symbols are symbols with the same address. | |
265 | */ | |
266 | while (low && kallsyms_sym_address(low-1) == kallsyms_sym_address(low)) | |
267 | --low; | |
268 | ||
269 | symbol_start = kallsyms_sym_address(low); | |
270 | ||
271 | /* Search for next non-aliased symbol. */ | |
272 | for (i = low + 1; i < kallsyms_num_syms; i++) { | |
273 | if (kallsyms_sym_address(i) > symbol_start) { | |
274 | symbol_end = kallsyms_sym_address(i); | |
275 | break; | |
276 | } | |
277 | } | |
278 | ||
279 | /* If we found no next symbol, we use the end of the section. */ | |
280 | if (!symbol_end) { | |
281 | if (is_kernel_inittext(addr)) | |
282 | symbol_end = (unsigned long)_einittext; | |
283 | else if (all_var) | |
284 | symbol_end = (unsigned long)_end; | |
285 | else | |
286 | symbol_end = (unsigned long)_etext; | |
287 | } | |
288 | ||
289 | if (symbolsize) | |
290 | *symbolsize = symbol_end - symbol_start; | |
291 | if (offset) | |
292 | *offset = addr - symbol_start; | |
293 | ||
294 | return low; | |
295 | } | |
296 | ||
297 | /* | |
298 | * Lookup an address but don't bother to find any names. | |
299 | */ | |
300 | int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize, | |
301 | unsigned long *offset) | |
302 | { | |
303 | char namebuf[KSYM_NAME_LEN]; | |
304 | ||
305 | if (is_ksym_addr(addr)) | |
306 | return !!get_symbol_pos(addr, symbolsize, offset); | |
307 | return !!module_address_lookup(addr, symbolsize, offset, NULL, namebuf) || | |
308 | !!__bpf_address_lookup(addr, symbolsize, offset, namebuf); | |
309 | } | |
310 | ||
311 | /* | |
312 | * Lookup an address | |
313 | * - modname is set to NULL if it's in the kernel. | |
314 | * - We guarantee that the returned name is valid until we reschedule even if. | |
315 | * It resides in a module. | |
316 | * - We also guarantee that modname will be valid until rescheduled. | |
317 | */ | |
318 | const char *kallsyms_lookup(unsigned long addr, | |
319 | unsigned long *symbolsize, | |
320 | unsigned long *offset, | |
321 | char **modname, char *namebuf) | |
322 | { | |
323 | const char *ret; | |
324 | ||
325 | namebuf[KSYM_NAME_LEN - 1] = 0; | |
326 | namebuf[0] = 0; | |
327 | ||
328 | if (is_ksym_addr(addr)) { | |
329 | unsigned long pos; | |
330 | ||
331 | pos = get_symbol_pos(addr, symbolsize, offset); | |
332 | /* Grab name */ | |
333 | kallsyms_expand_symbol(get_symbol_offset(pos), | |
334 | namebuf, KSYM_NAME_LEN); | |
335 | if (modname) | |
336 | *modname = NULL; | |
337 | return namebuf; | |
338 | } | |
339 | ||
340 | /* See if it's in a module or a BPF JITed image. */ | |
341 | ret = module_address_lookup(addr, symbolsize, offset, | |
342 | modname, namebuf); | |
343 | if (!ret) | |
344 | ret = bpf_address_lookup(addr, symbolsize, | |
345 | offset, modname, namebuf); | |
346 | return ret; | |
347 | } | |
348 | ||
349 | int lookup_symbol_name(unsigned long addr, char *symname) | |
350 | { | |
351 | symname[0] = '\0'; | |
352 | symname[KSYM_NAME_LEN - 1] = '\0'; | |
353 | ||
354 | if (is_ksym_addr(addr)) { | |
355 | unsigned long pos; | |
356 | ||
357 | pos = get_symbol_pos(addr, NULL, NULL); | |
358 | /* Grab name */ | |
359 | kallsyms_expand_symbol(get_symbol_offset(pos), | |
360 | symname, KSYM_NAME_LEN); | |
361 | return 0; | |
362 | } | |
363 | /* See if it's in a module. */ | |
364 | return lookup_module_symbol_name(addr, symname); | |
365 | } | |
366 | ||
367 | int lookup_symbol_attrs(unsigned long addr, unsigned long *size, | |
368 | unsigned long *offset, char *modname, char *name) | |
369 | { | |
370 | name[0] = '\0'; | |
371 | name[KSYM_NAME_LEN - 1] = '\0'; | |
372 | ||
373 | if (is_ksym_addr(addr)) { | |
374 | unsigned long pos; | |
375 | ||
376 | pos = get_symbol_pos(addr, size, offset); | |
377 | /* Grab name */ | |
378 | kallsyms_expand_symbol(get_symbol_offset(pos), | |
379 | name, KSYM_NAME_LEN); | |
380 | modname[0] = '\0'; | |
381 | return 0; | |
382 | } | |
383 | /* See if it's in a module. */ | |
384 | return lookup_module_symbol_attrs(addr, size, offset, modname, name); | |
385 | } | |
386 | ||
387 | /* Look up a kernel symbol and return it in a text buffer. */ | |
388 | static int __sprint_symbol(char *buffer, unsigned long address, | |
389 | int symbol_offset, int add_offset) | |
390 | { | |
391 | char *modname; | |
392 | const char *name; | |
393 | unsigned long offset, size; | |
394 | int len; | |
395 | ||
396 | address += symbol_offset; | |
397 | name = kallsyms_lookup(address, &size, &offset, &modname, buffer); | |
398 | if (!name) | |
399 | return sprintf(buffer, "0x%lx", address - symbol_offset); | |
400 | ||
401 | if (name != buffer) | |
402 | strcpy(buffer, name); | |
403 | len = strlen(buffer); | |
404 | offset -= symbol_offset; | |
405 | ||
406 | if (add_offset) | |
407 | len += sprintf(buffer + len, "+%#lx/%#lx", offset, size); | |
408 | ||
409 | if (modname) | |
410 | len += sprintf(buffer + len, " [%s]", modname); | |
411 | ||
412 | return len; | |
413 | } | |
414 | ||
415 | /** | |
416 | * sprint_symbol - Look up a kernel symbol and return it in a text buffer | |
417 | * @buffer: buffer to be stored | |
418 | * @address: address to lookup | |
419 | * | |
420 | * This function looks up a kernel symbol with @address and stores its name, | |
421 | * offset, size and module name to @buffer if possible. If no symbol was found, | |
422 | * just saves its @address as is. | |
423 | * | |
424 | * This function returns the number of bytes stored in @buffer. | |
425 | */ | |
426 | int sprint_symbol(char *buffer, unsigned long address) | |
427 | { | |
428 | return __sprint_symbol(buffer, address, 0, 1); | |
429 | } | |
430 | EXPORT_SYMBOL_GPL(sprint_symbol); | |
431 | ||
432 | /** | |
433 | * sprint_symbol_no_offset - Look up a kernel symbol and return it in a text buffer | |
434 | * @buffer: buffer to be stored | |
435 | * @address: address to lookup | |
436 | * | |
437 | * This function looks up a kernel symbol with @address and stores its name | |
438 | * and module name to @buffer if possible. If no symbol was found, just saves | |
439 | * its @address as is. | |
440 | * | |
441 | * This function returns the number of bytes stored in @buffer. | |
442 | */ | |
443 | int sprint_symbol_no_offset(char *buffer, unsigned long address) | |
444 | { | |
445 | return __sprint_symbol(buffer, address, 0, 0); | |
446 | } | |
447 | EXPORT_SYMBOL_GPL(sprint_symbol_no_offset); | |
448 | ||
449 | /** | |
450 | * sprint_backtrace - Look up a backtrace symbol and return it in a text buffer | |
451 | * @buffer: buffer to be stored | |
452 | * @address: address to lookup | |
453 | * | |
454 | * This function is for stack backtrace and does the same thing as | |
455 | * sprint_symbol() but with modified/decreased @address. If there is a | |
456 | * tail-call to the function marked "noreturn", gcc optimized out code after | |
457 | * the call so that the stack-saved return address could point outside of the | |
458 | * caller. This function ensures that kallsyms will find the original caller | |
459 | * by decreasing @address. | |
460 | * | |
461 | * This function returns the number of bytes stored in @buffer. | |
462 | */ | |
463 | int sprint_backtrace(char *buffer, unsigned long address) | |
464 | { | |
465 | return __sprint_symbol(buffer, address, -1, 1); | |
466 | } | |
467 | ||
468 | /* Look up a kernel symbol and print it to the kernel messages. */ | |
469 | void __print_symbol(const char *fmt, unsigned long address) | |
470 | { | |
471 | char buffer[KSYM_SYMBOL_LEN]; | |
472 | ||
473 | sprint_symbol(buffer, address); | |
474 | ||
475 | printk(fmt, buffer); | |
476 | } | |
477 | EXPORT_SYMBOL(__print_symbol); | |
478 | ||
479 | /* To avoid using get_symbol_offset for every symbol, we carry prefix along. */ | |
480 | struct kallsym_iter { | |
481 | loff_t pos; | |
482 | loff_t pos_mod_end; | |
483 | unsigned long value; | |
484 | unsigned int nameoff; /* If iterating in core kernel symbols. */ | |
485 | char type; | |
486 | char name[KSYM_NAME_LEN]; | |
487 | char module_name[MODULE_NAME_LEN]; | |
488 | int exported; | |
489 | }; | |
490 | ||
491 | static int get_ksymbol_mod(struct kallsym_iter *iter) | |
492 | { | |
493 | int ret = module_get_kallsym(iter->pos - kallsyms_num_syms, | |
494 | &iter->value, &iter->type, | |
495 | iter->name, iter->module_name, | |
496 | &iter->exported); | |
497 | if (ret < 0) { | |
498 | iter->pos_mod_end = iter->pos; | |
499 | return 0; | |
500 | } | |
501 | ||
502 | return 1; | |
503 | } | |
504 | ||
505 | static int get_ksymbol_bpf(struct kallsym_iter *iter) | |
506 | { | |
507 | iter->module_name[0] = '\0'; | |
508 | iter->exported = 0; | |
509 | return bpf_get_kallsym(iter->pos - iter->pos_mod_end, | |
510 | &iter->value, &iter->type, | |
511 | iter->name) < 0 ? 0 : 1; | |
512 | } | |
513 | ||
514 | /* Returns space to next name. */ | |
515 | static unsigned long get_ksymbol_core(struct kallsym_iter *iter) | |
516 | { | |
517 | unsigned off = iter->nameoff; | |
518 | ||
519 | iter->module_name[0] = '\0'; | |
520 | iter->value = kallsyms_sym_address(iter->pos); | |
521 | ||
522 | iter->type = kallsyms_get_symbol_type(off); | |
523 | ||
524 | off = kallsyms_expand_symbol(off, iter->name, ARRAY_SIZE(iter->name)); | |
525 | ||
526 | return off - iter->nameoff; | |
527 | } | |
528 | ||
529 | static void reset_iter(struct kallsym_iter *iter, loff_t new_pos) | |
530 | { | |
531 | iter->name[0] = '\0'; | |
532 | iter->nameoff = get_symbol_offset(new_pos); | |
533 | iter->pos = new_pos; | |
534 | if (new_pos == 0) | |
535 | iter->pos_mod_end = 0; | |
536 | } | |
537 | ||
538 | static int update_iter_mod(struct kallsym_iter *iter, loff_t pos) | |
539 | { | |
540 | iter->pos = pos; | |
541 | ||
542 | if (iter->pos_mod_end > 0 && | |
543 | iter->pos_mod_end < iter->pos) | |
544 | return get_ksymbol_bpf(iter); | |
545 | ||
546 | if (!get_ksymbol_mod(iter)) | |
547 | return get_ksymbol_bpf(iter); | |
548 | ||
549 | return 1; | |
550 | } | |
551 | ||
552 | /* Returns false if pos at or past end of file. */ | |
553 | static int update_iter(struct kallsym_iter *iter, loff_t pos) | |
554 | { | |
555 | /* Module symbols can be accessed randomly. */ | |
556 | if (pos >= kallsyms_num_syms) | |
557 | return update_iter_mod(iter, pos); | |
558 | ||
559 | /* If we're not on the desired position, reset to new position. */ | |
560 | if (pos != iter->pos) | |
561 | reset_iter(iter, pos); | |
562 | ||
563 | iter->nameoff += get_ksymbol_core(iter); | |
564 | iter->pos++; | |
565 | ||
566 | return 1; | |
567 | } | |
568 | ||
569 | static void *s_next(struct seq_file *m, void *p, loff_t *pos) | |
570 | { | |
571 | (*pos)++; | |
572 | ||
573 | if (!update_iter(m->private, *pos)) | |
574 | return NULL; | |
575 | return p; | |
576 | } | |
577 | ||
578 | static void *s_start(struct seq_file *m, loff_t *pos) | |
579 | { | |
580 | if (!update_iter(m->private, *pos)) | |
581 | return NULL; | |
582 | return m->private; | |
583 | } | |
584 | ||
585 | static void s_stop(struct seq_file *m, void *p) | |
586 | { | |
587 | } | |
588 | ||
589 | static int s_show(struct seq_file *m, void *p) | |
590 | { | |
591 | struct kallsym_iter *iter = m->private; | |
592 | ||
593 | /* Some debugging symbols have no name. Ignore them. */ | |
594 | if (!iter->name[0]) | |
595 | return 0; | |
596 | ||
597 | if (iter->module_name[0]) { | |
598 | char type; | |
599 | ||
600 | /* | |
601 | * Label it "global" if it is exported, | |
602 | * "local" if not exported. | |
603 | */ | |
604 | type = iter->exported ? toupper(iter->type) : | |
605 | tolower(iter->type); | |
606 | seq_printf(m, "%pK %c %s\t[%s]\n", (void *)iter->value, | |
607 | type, iter->name, iter->module_name); | |
608 | } else | |
609 | seq_printf(m, "%pK %c %s\n", (void *)iter->value, | |
610 | iter->type, iter->name); | |
611 | return 0; | |
612 | } | |
613 | ||
614 | static const struct seq_operations kallsyms_op = { | |
615 | .start = s_start, | |
616 | .next = s_next, | |
617 | .stop = s_stop, | |
618 | .show = s_show | |
619 | }; | |
620 | ||
621 | static int kallsyms_open(struct inode *inode, struct file *file) | |
622 | { | |
623 | /* | |
624 | * We keep iterator in m->private, since normal case is to | |
625 | * s_start from where we left off, so we avoid doing | |
626 | * using get_symbol_offset for every symbol. | |
627 | */ | |
628 | struct kallsym_iter *iter; | |
629 | iter = __seq_open_private(file, &kallsyms_op, sizeof(*iter)); | |
630 | if (!iter) | |
631 | return -ENOMEM; | |
632 | reset_iter(iter, 0); | |
633 | ||
634 | return 0; | |
635 | } | |
636 | ||
637 | #ifdef CONFIG_KGDB_KDB | |
638 | const char *kdb_walk_kallsyms(loff_t *pos) | |
639 | { | |
640 | static struct kallsym_iter kdb_walk_kallsyms_iter; | |
641 | if (*pos == 0) { | |
642 | memset(&kdb_walk_kallsyms_iter, 0, | |
643 | sizeof(kdb_walk_kallsyms_iter)); | |
644 | reset_iter(&kdb_walk_kallsyms_iter, 0); | |
645 | } | |
646 | while (1) { | |
647 | if (!update_iter(&kdb_walk_kallsyms_iter, *pos)) | |
648 | return NULL; | |
649 | ++*pos; | |
650 | /* Some debugging symbols have no name. Ignore them. */ | |
651 | if (kdb_walk_kallsyms_iter.name[0]) | |
652 | return kdb_walk_kallsyms_iter.name; | |
653 | } | |
654 | } | |
655 | #endif /* CONFIG_KGDB_KDB */ | |
656 | ||
657 | static const struct file_operations kallsyms_operations = { | |
658 | .open = kallsyms_open, | |
659 | .read = seq_read, | |
660 | .llseek = seq_lseek, | |
661 | .release = seq_release_private, | |
662 | }; | |
663 | ||
664 | static int __init kallsyms_init(void) | |
665 | { | |
666 | proc_create("kallsyms", 0444, NULL, &kallsyms_operations); | |
667 | return 0; | |
668 | } | |
669 | device_initcall(kallsyms_init); |