Commit | Line | Data |
---|---|---|
457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * kallsyms.c: in-kernel printing of symbolic oopses and stack traces. | |
4 | * | |
5 | * Rewritten and vastly simplified by Rusty Russell for in-kernel | |
6 | * module loader: | |
7 | * Copyright 2002 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation | |
8 | * | |
9 | * ChangeLog: | |
10 | * | |
11 | * (25/Aug/2004) Paulo Marques <pmarques@grupopie.com> | |
12 | * Changed the compression method from stem compression to "table lookup" | |
13 | * compression (see scripts/kallsyms.c for a more complete description) | |
14 | */ | |
15 | #include <linux/kallsyms.h> | |
1da177e4 LT |
16 | #include <linux/init.h> |
17 | #include <linux/seq_file.h> | |
18 | #include <linux/fs.h> | |
67fc4e0c | 19 | #include <linux/kdb.h> |
1da177e4 LT |
20 | #include <linux/err.h> |
21 | #include <linux/proc_fs.h> | |
4e57b681 | 22 | #include <linux/sched.h> /* for cond_resched */ |
07354a00 | 23 | #include <linux/ctype.h> |
5a0e3ad6 | 24 | #include <linux/slab.h> |
74451e66 | 25 | #include <linux/filter.h> |
aba4b5c2 | 26 | #include <linux/ftrace.h> |
52f5684c | 27 | #include <linux/compiler.h> |
1da177e4 | 28 | |
ad6ccfad MK |
29 | /* |
30 | * These will be re-linked against their real values | |
31 | * during the second link stage. | |
32 | */ | |
52f5684c | 33 | extern const unsigned long kallsyms_addresses[] __weak; |
2213e9a6 | 34 | extern const int kallsyms_offsets[] __weak; |
52f5684c | 35 | extern const u8 kallsyms_names[] __weak; |
1da177e4 | 36 | |
ad6ccfad MK |
37 | /* |
38 | * Tell the compiler that the count isn't in the small data section if the arch | |
39 | * has one (eg: FRV). | |
9e6c1e63 | 40 | */ |
80ffbaa5 | 41 | extern const unsigned int kallsyms_num_syms |
2ea03891 | 42 | __attribute__((weak, section(".rodata"))); |
9e6c1e63 | 43 | |
2213e9a6 AB |
44 | extern const unsigned long kallsyms_relative_base |
45 | __attribute__((weak, section(".rodata"))); | |
46 | ||
cde26a6e | 47 | extern const char kallsyms_token_table[] __weak; |
52f5684c | 48 | extern const u16 kallsyms_token_index[] __weak; |
1da177e4 | 49 | |
80ffbaa5 | 50 | extern const unsigned int kallsyms_markers[] __weak; |
1da177e4 | 51 | |
ad6ccfad MK |
52 | /* |
53 | * Expand a compressed symbol data into the resulting uncompressed string, | |
e3f26752 | 54 | * if uncompressed string is too long (>= maxlen), it will be truncated, |
ad6ccfad MK |
55 | * given the offset to where the symbol is in the compressed stream. |
56 | */ | |
e3f26752 CG |
57 | static unsigned int kallsyms_expand_symbol(unsigned int off, |
58 | char *result, size_t maxlen) | |
1da177e4 LT |
59 | { |
60 | int len, skipped_first = 0; | |
cde26a6e MY |
61 | const char *tptr; |
62 | const u8 *data; | |
1da177e4 | 63 | |
ad6ccfad | 64 | /* Get the compressed symbol length from the first symbol byte. */ |
1da177e4 LT |
65 | data = &kallsyms_names[off]; |
66 | len = *data; | |
67 | data++; | |
68 | ||
ad6ccfad MK |
69 | /* |
70 | * Update the offset to return the offset for the next symbol on | |
71 | * the compressed stream. | |
72 | */ | |
1da177e4 LT |
73 | off += len + 1; |
74 | ||
ad6ccfad MK |
75 | /* |
76 | * For every byte on the compressed symbol data, copy the table | |
77 | * entry for that byte. | |
78 | */ | |
79 | while (len) { | |
80 | tptr = &kallsyms_token_table[kallsyms_token_index[*data]]; | |
1da177e4 LT |
81 | data++; |
82 | len--; | |
83 | ||
84 | while (*tptr) { | |
ad6ccfad | 85 | if (skipped_first) { |
e3f26752 CG |
86 | if (maxlen <= 1) |
87 | goto tail; | |
1da177e4 LT |
88 | *result = *tptr; |
89 | result++; | |
e3f26752 | 90 | maxlen--; |
1da177e4 LT |
91 | } else |
92 | skipped_first = 1; | |
93 | tptr++; | |
94 | } | |
95 | } | |
96 | ||
e3f26752 CG |
97 | tail: |
98 | if (maxlen) | |
99 | *result = '\0'; | |
1da177e4 | 100 | |
ad6ccfad | 101 | /* Return to offset to the next symbol. */ |
1da177e4 LT |
102 | return off; |
103 | } | |
104 | ||
ad6ccfad MK |
105 | /* |
106 | * Get symbol type information. This is encoded as a single char at the | |
107 | * beginning of the symbol name. | |
108 | */ | |
1da177e4 LT |
109 | static char kallsyms_get_symbol_type(unsigned int off) |
110 | { | |
ad6ccfad MK |
111 | /* |
112 | * Get just the first code, look it up in the token table, | |
113 | * and return the first char from this token. | |
114 | */ | |
115 | return kallsyms_token_table[kallsyms_token_index[kallsyms_names[off + 1]]]; | |
1da177e4 LT |
116 | } |
117 | ||
118 | ||
ad6ccfad MK |
119 | /* |
120 | * Find the offset on the compressed stream given and index in the | |
121 | * kallsyms array. | |
122 | */ | |
1da177e4 LT |
123 | static unsigned int get_symbol_offset(unsigned long pos) |
124 | { | |
aad09470 | 125 | const u8 *name; |
1da177e4 LT |
126 | int i; |
127 | ||
ad6ccfad MK |
128 | /* |
129 | * Use the closest marker we have. We have markers every 256 positions, | |
130 | * so that should be close enough. | |
131 | */ | |
132 | name = &kallsyms_names[kallsyms_markers[pos >> 8]]; | |
1da177e4 | 133 | |
ad6ccfad MK |
134 | /* |
135 | * Sequentially scan all the symbols up to the point we're searching | |
136 | * for. Every symbol is stored in a [<len>][<len> bytes of data] format, | |
137 | * so we just need to add the len to the current pointer for every | |
138 | * symbol we wish to skip. | |
139 | */ | |
140 | for (i = 0; i < (pos & 0xFF); i++) | |
1da177e4 LT |
141 | name = name + (*name) + 1; |
142 | ||
143 | return name - kallsyms_names; | |
144 | } | |
145 | ||
2213e9a6 AB |
146 | static unsigned long kallsyms_sym_address(int idx) |
147 | { | |
148 | if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE)) | |
149 | return kallsyms_addresses[idx]; | |
150 | ||
151 | /* values are unsigned offsets if --absolute-percpu is not in effect */ | |
152 | if (!IS_ENABLED(CONFIG_KALLSYMS_ABSOLUTE_PERCPU)) | |
153 | return kallsyms_relative_base + (u32)kallsyms_offsets[idx]; | |
154 | ||
155 | /* ...otherwise, positive offsets are absolute values */ | |
156 | if (kallsyms_offsets[idx] >= 0) | |
157 | return kallsyms_offsets[idx]; | |
158 | ||
159 | /* ...and negative offsets are relative to kallsyms_relative_base - 1 */ | |
160 | return kallsyms_relative_base - 1 - kallsyms_offsets[idx]; | |
161 | } | |
162 | ||
1da177e4 LT |
163 | /* Lookup the address for this symbol. Returns 0 if not found. */ |
164 | unsigned long kallsyms_lookup_name(const char *name) | |
165 | { | |
9281acea | 166 | char namebuf[KSYM_NAME_LEN]; |
1da177e4 LT |
167 | unsigned long i; |
168 | unsigned int off; | |
169 | ||
170 | for (i = 0, off = 0; i < kallsyms_num_syms; i++) { | |
e3f26752 | 171 | off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf)); |
1da177e4 LT |
172 | |
173 | if (strcmp(namebuf, name) == 0) | |
2213e9a6 | 174 | return kallsyms_sym_address(i); |
1da177e4 LT |
175 | } |
176 | return module_kallsyms_lookup_name(name); | |
177 | } | |
f60d24d2 | 178 | EXPORT_SYMBOL_GPL(kallsyms_lookup_name); |
1da177e4 | 179 | |
75a66614 AK |
180 | int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *, |
181 | unsigned long), | |
182 | void *data) | |
183 | { | |
184 | char namebuf[KSYM_NAME_LEN]; | |
185 | unsigned long i; | |
186 | unsigned int off; | |
187 | int ret; | |
188 | ||
189 | for (i = 0, off = 0; i < kallsyms_num_syms; i++) { | |
e3f26752 | 190 | off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf)); |
2213e9a6 | 191 | ret = fn(data, namebuf, NULL, kallsyms_sym_address(i)); |
75a66614 AK |
192 | if (ret != 0) |
193 | return ret; | |
194 | } | |
195 | return module_kallsyms_on_each_symbol(fn, data); | |
196 | } | |
197 | EXPORT_SYMBOL_GPL(kallsyms_on_each_symbol); | |
198 | ||
ffc50891 FBH |
199 | static unsigned long get_symbol_pos(unsigned long addr, |
200 | unsigned long *symbolsize, | |
201 | unsigned long *offset) | |
202 | { | |
203 | unsigned long symbol_start = 0, symbol_end = 0; | |
204 | unsigned long i, low, high, mid; | |
205 | ||
2ea03891 | 206 | /* This kernel should never had been booted. */ |
2213e9a6 AB |
207 | if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE)) |
208 | BUG_ON(!kallsyms_addresses); | |
209 | else | |
210 | BUG_ON(!kallsyms_offsets); | |
2ea03891 | 211 | |
ad6ccfad | 212 | /* Do a binary search on the sorted kallsyms_addresses array. */ |
ffc50891 FBH |
213 | low = 0; |
214 | high = kallsyms_num_syms; | |
215 | ||
216 | while (high - low > 1) { | |
2fc9c4e1 | 217 | mid = low + (high - low) / 2; |
2213e9a6 | 218 | if (kallsyms_sym_address(mid) <= addr) |
ffc50891 FBH |
219 | low = mid; |
220 | else | |
221 | high = mid; | |
222 | } | |
223 | ||
224 | /* | |
ad6ccfad MK |
225 | * Search for the first aliased symbol. Aliased |
226 | * symbols are symbols with the same address. | |
ffc50891 | 227 | */ |
2213e9a6 | 228 | while (low && kallsyms_sym_address(low-1) == kallsyms_sym_address(low)) |
ffc50891 FBH |
229 | --low; |
230 | ||
2213e9a6 | 231 | symbol_start = kallsyms_sym_address(low); |
ffc50891 | 232 | |
ad6ccfad | 233 | /* Search for next non-aliased symbol. */ |
ffc50891 | 234 | for (i = low + 1; i < kallsyms_num_syms; i++) { |
2213e9a6 AB |
235 | if (kallsyms_sym_address(i) > symbol_start) { |
236 | symbol_end = kallsyms_sym_address(i); | |
ffc50891 FBH |
237 | break; |
238 | } | |
239 | } | |
240 | ||
ad6ccfad | 241 | /* If we found no next symbol, we use the end of the section. */ |
ffc50891 FBH |
242 | if (!symbol_end) { |
243 | if (is_kernel_inittext(addr)) | |
244 | symbol_end = (unsigned long)_einittext; | |
63b23e2c | 245 | else if (IS_ENABLED(CONFIG_KALLSYMS_ALL)) |
ffc50891 FBH |
246 | symbol_end = (unsigned long)_end; |
247 | else | |
248 | symbol_end = (unsigned long)_etext; | |
249 | } | |
250 | ||
ffb45122 AD |
251 | if (symbolsize) |
252 | *symbolsize = symbol_end - symbol_start; | |
253 | if (offset) | |
254 | *offset = addr - symbol_start; | |
ffc50891 FBH |
255 | |
256 | return low; | |
257 | } | |
258 | ||
259 | /* | |
260 | * Lookup an address but don't bother to find any names. | |
261 | */ | |
262 | int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize, | |
263 | unsigned long *offset) | |
264 | { | |
6dd06c9f | 265 | char namebuf[KSYM_NAME_LEN]; |
74451e66 | 266 | |
2a1a3fa0 MZ |
267 | if (is_ksym_addr(addr)) { |
268 | get_symbol_pos(addr, symbolsize, offset); | |
269 | return 1; | |
270 | } | |
74451e66 DB |
271 | return !!module_address_lookup(addr, symbolsize, offset, NULL, namebuf) || |
272 | !!__bpf_address_lookup(addr, symbolsize, offset, namebuf); | |
ffc50891 FBH |
273 | } |
274 | ||
1da177e4 LT |
275 | /* |
276 | * Lookup an address | |
ad6ccfad MK |
277 | * - modname is set to NULL if it's in the kernel. |
278 | * - We guarantee that the returned name is valid until we reschedule even if. | |
279 | * It resides in a module. | |
280 | * - We also guarantee that modname will be valid until rescheduled. | |
1da177e4 LT |
281 | */ |
282 | const char *kallsyms_lookup(unsigned long addr, | |
283 | unsigned long *symbolsize, | |
284 | unsigned long *offset, | |
285 | char **modname, char *namebuf) | |
286 | { | |
74451e66 DB |
287 | const char *ret; |
288 | ||
9281acea | 289 | namebuf[KSYM_NAME_LEN - 1] = 0; |
1da177e4 LT |
290 | namebuf[0] = 0; |
291 | ||
ffc50891 FBH |
292 | if (is_ksym_addr(addr)) { |
293 | unsigned long pos; | |
1da177e4 | 294 | |
ffc50891 | 295 | pos = get_symbol_pos(addr, symbolsize, offset); |
1da177e4 | 296 | /* Grab name */ |
e3f26752 CG |
297 | kallsyms_expand_symbol(get_symbol_offset(pos), |
298 | namebuf, KSYM_NAME_LEN); | |
7a74fc49 KM |
299 | if (modname) |
300 | *modname = NULL; | |
1da177e4 LT |
301 | return namebuf; |
302 | } | |
303 | ||
74451e66 DB |
304 | /* See if it's in a module or a BPF JITed image. */ |
305 | ret = module_address_lookup(addr, symbolsize, offset, | |
306 | modname, namebuf); | |
307 | if (!ret) | |
308 | ret = bpf_address_lookup(addr, symbolsize, | |
309 | offset, modname, namebuf); | |
aba4b5c2 SRV |
310 | |
311 | if (!ret) | |
312 | ret = ftrace_mod_address_lookup(addr, symbolsize, | |
313 | offset, modname, namebuf); | |
74451e66 | 314 | return ret; |
1da177e4 LT |
315 | } |
316 | ||
9d65cb4a AD |
317 | int lookup_symbol_name(unsigned long addr, char *symname) |
318 | { | |
319 | symname[0] = '\0'; | |
9281acea | 320 | symname[KSYM_NAME_LEN - 1] = '\0'; |
9d65cb4a AD |
321 | |
322 | if (is_ksym_addr(addr)) { | |
323 | unsigned long pos; | |
324 | ||
325 | pos = get_symbol_pos(addr, NULL, NULL); | |
326 | /* Grab name */ | |
e3f26752 CG |
327 | kallsyms_expand_symbol(get_symbol_offset(pos), |
328 | symname, KSYM_NAME_LEN); | |
9d65cb4a AD |
329 | return 0; |
330 | } | |
ad6ccfad | 331 | /* See if it's in a module. */ |
9d65cb4a AD |
332 | return lookup_module_symbol_name(addr, symname); |
333 | } | |
334 | ||
a5c43dae AD |
335 | int lookup_symbol_attrs(unsigned long addr, unsigned long *size, |
336 | unsigned long *offset, char *modname, char *name) | |
337 | { | |
338 | name[0] = '\0'; | |
9281acea | 339 | name[KSYM_NAME_LEN - 1] = '\0'; |
a5c43dae AD |
340 | |
341 | if (is_ksym_addr(addr)) { | |
342 | unsigned long pos; | |
343 | ||
344 | pos = get_symbol_pos(addr, size, offset); | |
345 | /* Grab name */ | |
e3f26752 CG |
346 | kallsyms_expand_symbol(get_symbol_offset(pos), |
347 | name, KSYM_NAME_LEN); | |
a5c43dae AD |
348 | modname[0] = '\0'; |
349 | return 0; | |
350 | } | |
ad6ccfad | 351 | /* See if it's in a module. */ |
a5c43dae AD |
352 | return lookup_module_symbol_attrs(addr, size, offset, modname, name); |
353 | } | |
354 | ||
42e38083 | 355 | /* Look up a kernel symbol and return it in a text buffer. */ |
0f77a8d3 | 356 | static int __sprint_symbol(char *buffer, unsigned long address, |
4796dd20 | 357 | int symbol_offset, int add_offset) |
1da177e4 LT |
358 | { |
359 | char *modname; | |
360 | const char *name; | |
361 | unsigned long offset, size; | |
966c8c12 | 362 | int len; |
1da177e4 | 363 | |
0f77a8d3 | 364 | address += symbol_offset; |
966c8c12 | 365 | name = kallsyms_lookup(address, &size, &offset, &modname, buffer); |
1da177e4 | 366 | if (!name) |
b86280aa | 367 | return sprintf(buffer, "0x%lx", address - symbol_offset); |
19769b76 | 368 | |
966c8c12 HD |
369 | if (name != buffer) |
370 | strcpy(buffer, name); | |
371 | len = strlen(buffer); | |
0f77a8d3 | 372 | offset -= symbol_offset; |
966c8c12 | 373 | |
4796dd20 SB |
374 | if (add_offset) |
375 | len += sprintf(buffer + len, "+%#lx/%#lx", offset, size); | |
376 | ||
19769b76 | 377 | if (modname) |
4796dd20 | 378 | len += sprintf(buffer + len, " [%s]", modname); |
966c8c12 HD |
379 | |
380 | return len; | |
42e38083 | 381 | } |
0f77a8d3 NK |
382 | |
383 | /** | |
384 | * sprint_symbol - Look up a kernel symbol and return it in a text buffer | |
385 | * @buffer: buffer to be stored | |
386 | * @address: address to lookup | |
387 | * | |
388 | * This function looks up a kernel symbol with @address and stores its name, | |
389 | * offset, size and module name to @buffer if possible. If no symbol was found, | |
390 | * just saves its @address as is. | |
391 | * | |
392 | * This function returns the number of bytes stored in @buffer. | |
393 | */ | |
394 | int sprint_symbol(char *buffer, unsigned long address) | |
395 | { | |
4796dd20 | 396 | return __sprint_symbol(buffer, address, 0, 1); |
0f77a8d3 | 397 | } |
ad6ccfad | 398 | EXPORT_SYMBOL_GPL(sprint_symbol); |
42e38083 | 399 | |
4796dd20 SB |
400 | /** |
401 | * sprint_symbol_no_offset - Look up a kernel symbol and return it in a text buffer | |
402 | * @buffer: buffer to be stored | |
403 | * @address: address to lookup | |
404 | * | |
405 | * This function looks up a kernel symbol with @address and stores its name | |
406 | * and module name to @buffer if possible. If no symbol was found, just saves | |
407 | * its @address as is. | |
408 | * | |
409 | * This function returns the number of bytes stored in @buffer. | |
410 | */ | |
411 | int sprint_symbol_no_offset(char *buffer, unsigned long address) | |
412 | { | |
413 | return __sprint_symbol(buffer, address, 0, 0); | |
414 | } | |
415 | EXPORT_SYMBOL_GPL(sprint_symbol_no_offset); | |
416 | ||
0f77a8d3 NK |
417 | /** |
418 | * sprint_backtrace - Look up a backtrace symbol and return it in a text buffer | |
419 | * @buffer: buffer to be stored | |
420 | * @address: address to lookup | |
421 | * | |
422 | * This function is for stack backtrace and does the same thing as | |
423 | * sprint_symbol() but with modified/decreased @address. If there is a | |
424 | * tail-call to the function marked "noreturn", gcc optimized out code after | |
425 | * the call so that the stack-saved return address could point outside of the | |
426 | * caller. This function ensures that kallsyms will find the original caller | |
427 | * by decreasing @address. | |
428 | * | |
429 | * This function returns the number of bytes stored in @buffer. | |
430 | */ | |
431 | int sprint_backtrace(char *buffer, unsigned long address) | |
432 | { | |
4796dd20 | 433 | return __sprint_symbol(buffer, address, -1, 1); |
0f77a8d3 NK |
434 | } |
435 | ||
1da177e4 | 436 | /* To avoid using get_symbol_offset for every symbol, we carry prefix along. */ |
ad6ccfad | 437 | struct kallsym_iter { |
1da177e4 | 438 | loff_t pos; |
d83212d5 | 439 | loff_t pos_arch_end; |
74451e66 | 440 | loff_t pos_mod_end; |
6171a031 | 441 | loff_t pos_ftrace_mod_end; |
1da177e4 | 442 | unsigned long value; |
ad6ccfad | 443 | unsigned int nameoff; /* If iterating in core kernel symbols. */ |
1da177e4 | 444 | char type; |
9281acea TH |
445 | char name[KSYM_NAME_LEN]; |
446 | char module_name[MODULE_NAME_LEN]; | |
ea07890a | 447 | int exported; |
c0f3ea15 | 448 | int show_value; |
1da177e4 LT |
449 | }; |
450 | ||
d83212d5 AS |
451 | int __weak arch_get_kallsym(unsigned int symnum, unsigned long *value, |
452 | char *type, char *name) | |
453 | { | |
454 | return -EINVAL; | |
455 | } | |
456 | ||
457 | static int get_ksymbol_arch(struct kallsym_iter *iter) | |
458 | { | |
459 | int ret = arch_get_kallsym(iter->pos - kallsyms_num_syms, | |
460 | &iter->value, &iter->type, | |
461 | iter->name); | |
462 | ||
463 | if (ret < 0) { | |
464 | iter->pos_arch_end = iter->pos; | |
465 | return 0; | |
466 | } | |
467 | ||
468 | return 1; | |
469 | } | |
470 | ||
1da177e4 LT |
471 | static int get_ksymbol_mod(struct kallsym_iter *iter) |
472 | { | |
d83212d5 | 473 | int ret = module_get_kallsym(iter->pos - iter->pos_arch_end, |
74451e66 DB |
474 | &iter->value, &iter->type, |
475 | iter->name, iter->module_name, | |
476 | &iter->exported); | |
477 | if (ret < 0) { | |
478 | iter->pos_mod_end = iter->pos; | |
1da177e4 | 479 | return 0; |
74451e66 DB |
480 | } |
481 | ||
1da177e4 LT |
482 | return 1; |
483 | } | |
484 | ||
6171a031 SRV |
485 | static int get_ksymbol_ftrace_mod(struct kallsym_iter *iter) |
486 | { | |
487 | int ret = ftrace_mod_get_kallsym(iter->pos - iter->pos_mod_end, | |
488 | &iter->value, &iter->type, | |
489 | iter->name, iter->module_name, | |
490 | &iter->exported); | |
491 | if (ret < 0) { | |
492 | iter->pos_ftrace_mod_end = iter->pos; | |
493 | return 0; | |
494 | } | |
495 | ||
496 | return 1; | |
497 | } | |
498 | ||
74451e66 DB |
499 | static int get_ksymbol_bpf(struct kallsym_iter *iter) |
500 | { | |
6934058d | 501 | strlcpy(iter->module_name, "bpf", MODULE_NAME_LEN); |
74451e66 | 502 | iter->exported = 0; |
6171a031 | 503 | return bpf_get_kallsym(iter->pos - iter->pos_ftrace_mod_end, |
74451e66 DB |
504 | &iter->value, &iter->type, |
505 | iter->name) < 0 ? 0 : 1; | |
506 | } | |
507 | ||
1da177e4 LT |
508 | /* Returns space to next name. */ |
509 | static unsigned long get_ksymbol_core(struct kallsym_iter *iter) | |
510 | { | |
511 | unsigned off = iter->nameoff; | |
512 | ||
ea07890a | 513 | iter->module_name[0] = '\0'; |
2213e9a6 | 514 | iter->value = kallsyms_sym_address(iter->pos); |
1da177e4 LT |
515 | |
516 | iter->type = kallsyms_get_symbol_type(off); | |
517 | ||
e3f26752 | 518 | off = kallsyms_expand_symbol(off, iter->name, ARRAY_SIZE(iter->name)); |
1da177e4 LT |
519 | |
520 | return off - iter->nameoff; | |
521 | } | |
522 | ||
523 | static void reset_iter(struct kallsym_iter *iter, loff_t new_pos) | |
524 | { | |
525 | iter->name[0] = '\0'; | |
526 | iter->nameoff = get_symbol_offset(new_pos); | |
527 | iter->pos = new_pos; | |
6171a031 | 528 | if (new_pos == 0) { |
d83212d5 | 529 | iter->pos_arch_end = 0; |
74451e66 | 530 | iter->pos_mod_end = 0; |
6171a031 SRV |
531 | iter->pos_ftrace_mod_end = 0; |
532 | } | |
74451e66 DB |
533 | } |
534 | ||
b9667942 AH |
535 | /* |
536 | * The end position (last + 1) of each additional kallsyms section is recorded | |
537 | * in iter->pos_..._end as each section is added, and so can be used to | |
538 | * determine which get_ksymbol_...() function to call next. | |
539 | */ | |
74451e66 DB |
540 | static int update_iter_mod(struct kallsym_iter *iter, loff_t pos) |
541 | { | |
542 | iter->pos = pos; | |
543 | ||
d83212d5 AS |
544 | if ((!iter->pos_arch_end || iter->pos_arch_end > pos) && |
545 | get_ksymbol_arch(iter)) | |
546 | return 1; | |
547 | ||
b9667942 AH |
548 | if ((!iter->pos_mod_end || iter->pos_mod_end > pos) && |
549 | get_ksymbol_mod(iter)) | |
6171a031 | 550 | return 1; |
6171a031 | 551 | |
b9667942 AH |
552 | if ((!iter->pos_ftrace_mod_end || iter->pos_ftrace_mod_end > pos) && |
553 | get_ksymbol_ftrace_mod(iter)) | |
554 | return 1; | |
74451e66 | 555 | |
b9667942 | 556 | return get_ksymbol_bpf(iter); |
1da177e4 LT |
557 | } |
558 | ||
559 | /* Returns false if pos at or past end of file. */ | |
560 | static int update_iter(struct kallsym_iter *iter, loff_t pos) | |
561 | { | |
562 | /* Module symbols can be accessed randomly. */ | |
74451e66 DB |
563 | if (pos >= kallsyms_num_syms) |
564 | return update_iter_mod(iter, pos); | |
ad6ccfad | 565 | |
1da177e4 LT |
566 | /* If we're not on the desired position, reset to new position. */ |
567 | if (pos != iter->pos) | |
568 | reset_iter(iter, pos); | |
569 | ||
570 | iter->nameoff += get_ksymbol_core(iter); | |
571 | iter->pos++; | |
572 | ||
573 | return 1; | |
574 | } | |
575 | ||
576 | static void *s_next(struct seq_file *m, void *p, loff_t *pos) | |
577 | { | |
578 | (*pos)++; | |
579 | ||
580 | if (!update_iter(m->private, *pos)) | |
581 | return NULL; | |
582 | return p; | |
583 | } | |
584 | ||
585 | static void *s_start(struct seq_file *m, loff_t *pos) | |
586 | { | |
587 | if (!update_iter(m->private, *pos)) | |
588 | return NULL; | |
589 | return m->private; | |
590 | } | |
591 | ||
592 | static void s_stop(struct seq_file *m, void *p) | |
593 | { | |
594 | } | |
595 | ||
596 | static int s_show(struct seq_file *m, void *p) | |
597 | { | |
668533dc | 598 | void *value; |
1da177e4 LT |
599 | struct kallsym_iter *iter = m->private; |
600 | ||
ad6ccfad | 601 | /* Some debugging symbols have no name. Ignore them. */ |
1da177e4 LT |
602 | if (!iter->name[0]) |
603 | return 0; | |
604 | ||
668533dc | 605 | value = iter->show_value ? (void *)iter->value : NULL; |
c0f3ea15 | 606 | |
ea07890a AD |
607 | if (iter->module_name[0]) { |
608 | char type; | |
609 | ||
ad6ccfad MK |
610 | /* |
611 | * Label it "global" if it is exported, | |
612 | * "local" if not exported. | |
613 | */ | |
ea07890a AD |
614 | type = iter->exported ? toupper(iter->type) : |
615 | tolower(iter->type); | |
668533dc | 616 | seq_printf(m, "%px %c %s\t[%s]\n", value, |
9f36e2c4 | 617 | type, iter->name, iter->module_name); |
ea07890a | 618 | } else |
668533dc | 619 | seq_printf(m, "%px %c %s\n", value, |
9f36e2c4 | 620 | iter->type, iter->name); |
1da177e4 LT |
621 | return 0; |
622 | } | |
623 | ||
15ad7cdc | 624 | static const struct seq_operations kallsyms_op = { |
1da177e4 LT |
625 | .start = s_start, |
626 | .next = s_next, | |
627 | .stop = s_stop, | |
628 | .show = s_show | |
629 | }; | |
630 | ||
c0f3ea15 LT |
631 | static inline int kallsyms_for_perf(void) |
632 | { | |
633 | #ifdef CONFIG_PERF_EVENTS | |
634 | extern int sysctl_perf_event_paranoid; | |
635 | if (sysctl_perf_event_paranoid <= 1) | |
636 | return 1; | |
637 | #endif | |
638 | return 0; | |
639 | } | |
640 | ||
641 | /* | |
642 | * We show kallsyms information even to normal users if we've enabled | |
643 | * kernel profiling and are explicitly not paranoid (so kptr_restrict | |
644 | * is clear, and sysctl_perf_event_paranoid isn't set). | |
645 | * | |
646 | * Otherwise, require CAP_SYSLOG (assuming kptr_restrict isn't set to | |
647 | * block even that). | |
648 | */ | |
516fb7f2 | 649 | int kallsyms_show_value(void) |
c0f3ea15 LT |
650 | { |
651 | switch (kptr_restrict) { | |
652 | case 0: | |
653 | if (kallsyms_for_perf()) | |
654 | return 1; | |
655 | /* fallthrough */ | |
656 | case 1: | |
657 | if (has_capability_noaudit(current, CAP_SYSLOG)) | |
658 | return 1; | |
659 | /* fallthrough */ | |
660 | default: | |
661 | return 0; | |
662 | } | |
663 | } | |
664 | ||
1da177e4 LT |
665 | static int kallsyms_open(struct inode *inode, struct file *file) |
666 | { | |
ad6ccfad MK |
667 | /* |
668 | * We keep iterator in m->private, since normal case is to | |
1da177e4 | 669 | * s_start from where we left off, so we avoid doing |
ad6ccfad MK |
670 | * using get_symbol_offset for every symbol. |
671 | */ | |
1da177e4 | 672 | struct kallsym_iter *iter; |
0049f26a | 673 | iter = __seq_open_private(file, &kallsyms_op, sizeof(*iter)); |
1da177e4 LT |
674 | if (!iter) |
675 | return -ENOMEM; | |
676 | reset_iter(iter, 0); | |
677 | ||
c0f3ea15 | 678 | iter->show_value = kallsyms_show_value(); |
0049f26a | 679 | return 0; |
1da177e4 LT |
680 | } |
681 | ||
67fc4e0c JW |
682 | #ifdef CONFIG_KGDB_KDB |
683 | const char *kdb_walk_kallsyms(loff_t *pos) | |
684 | { | |
685 | static struct kallsym_iter kdb_walk_kallsyms_iter; | |
686 | if (*pos == 0) { | |
687 | memset(&kdb_walk_kallsyms_iter, 0, | |
688 | sizeof(kdb_walk_kallsyms_iter)); | |
689 | reset_iter(&kdb_walk_kallsyms_iter, 0); | |
690 | } | |
691 | while (1) { | |
692 | if (!update_iter(&kdb_walk_kallsyms_iter, *pos)) | |
693 | return NULL; | |
694 | ++*pos; | |
695 | /* Some debugging symbols have no name. Ignore them. */ | |
696 | if (kdb_walk_kallsyms_iter.name[0]) | |
697 | return kdb_walk_kallsyms_iter.name; | |
698 | } | |
699 | } | |
700 | #endif /* CONFIG_KGDB_KDB */ | |
701 | ||
97a32539 AD |
702 | static const struct proc_ops kallsyms_proc_ops = { |
703 | .proc_open = kallsyms_open, | |
704 | .proc_read = seq_read, | |
705 | .proc_lseek = seq_lseek, | |
706 | .proc_release = seq_release_private, | |
1da177e4 LT |
707 | }; |
708 | ||
709 | static int __init kallsyms_init(void) | |
710 | { | |
97a32539 | 711 | proc_create("kallsyms", 0444, NULL, &kallsyms_proc_ops); |
1da177e4 LT |
712 | return 0; |
713 | } | |
ad6ccfad | 714 | device_initcall(kallsyms_init); |