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1da177e Linux-2.6.12-rc2
Linus Torvalds authored
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>
67fc4e0 @jwessel kdb: core for kgdb back end (2 of 2)
jwessel authored
19 #include <linux/kdb.h>
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
20 #include <linux/err.h>
21 #include <linux/proc_fs.h>
4e57b68 [PATCH] fix missing includes
Tim Schmielau authored
22 #include <linux/sched.h> /* for cond_resched */
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
23 #include <linux/mm.h>
07354a0 @adamjerome [PATCH] /proc/kallsyms reports lower-case types for some non-exported…
adamjerome authored
24 #include <linux/ctype.h>
5a0e3ad include cleanup: Update gfp.h and slab.h includes to prepare for brea…
Tejun Heo authored
25 #include <linux/slab.h>
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
26
27 #include <asm/sections.h>
28
29 #ifdef CONFIG_KALLSYMS_ALL
30 #define all_var 1
31 #else
32 #define all_var 0
33 #endif
34
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
35 /*
36 * These will be re-linked against their real values
37 * during the second link stage.
38 */
2ea0389 Revert "kbuild: strip generated symbols from *.ko"
Sam Ravnborg authored
39 extern const unsigned long kallsyms_addresses[] __attribute__((weak));
40 extern const u8 kallsyms_names[] __attribute__((weak));
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
41
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
42 /*
43 * Tell the compiler that the count isn't in the small data section if the arch
44 * has one (eg: FRV).
9e6c1e6 FRV: fix the extern declaration of kallsyms_num_syms
David Howells authored
45 */
46 extern const unsigned long kallsyms_num_syms
2ea0389 Revert "kbuild: strip generated symbols from *.ko"
Sam Ravnborg authored
47 __attribute__((weak, section(".rodata")));
9e6c1e6 FRV: fix the extern declaration of kallsyms_num_syms
David Howells authored
48
2ea0389 Revert "kbuild: strip generated symbols from *.ko"
Sam Ravnborg authored
49 extern const u8 kallsyms_token_table[] __attribute__((weak));
50 extern const u16 kallsyms_token_index[] __attribute__((weak));
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
51
2ea0389 Revert "kbuild: strip generated symbols from *.ko"
Sam Ravnborg authored
52 extern const unsigned long kallsyms_markers[] __attribute__((weak));
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
53
54 static inline int is_kernel_inittext(unsigned long addr)
55 {
56 if (addr >= (unsigned long)_sinittext
57 && addr <= (unsigned long)_einittext)
58 return 1;
59 return 0;
60 }
61
62 static inline int is_kernel_text(unsigned long addr)
63 {
128e8db @vapier kallsyms: use new arch_is_kernel_text()
vapier authored
64 if ((addr >= (unsigned long)_stext && addr <= (unsigned long)_etext) ||
65 arch_is_kernel_text(addr))
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
66 return 1;
cae5d39 mm: arch: rename in_gate_area_no_task to in_gate_area_no_mm
Stephen Wilson authored
67 return in_gate_area_no_mm(addr);
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
68 }
69
70 static inline int is_kernel(unsigned long addr)
71 {
72 if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
73 return 1;
cae5d39 mm: arch: rename in_gate_area_no_task to in_gate_area_no_mm
Stephen Wilson authored
74 return in_gate_area_no_mm(addr);
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
75 }
76
ffc5089 [PATCH] Create kallsyms_lookup_size_offset()
Franck Bui-Huu authored
77 static int is_ksym_addr(unsigned long addr)
78 {
79 if (all_var)
80 return is_kernel(addr);
81
a3b8111 remove support for un-needed _extratext section
Robin Getz authored
82 return is_kernel_text(addr) || is_kernel_inittext(addr);
ffc5089 [PATCH] Create kallsyms_lookup_size_offset()
Franck Bui-Huu authored
83 }
84
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
85 /*
86 * Expand a compressed symbol data into the resulting uncompressed string,
87 * given the offset to where the symbol is in the compressed stream.
88 */
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
89 static unsigned int kallsyms_expand_symbol(unsigned int off, char *result)
90 {
91 int len, skipped_first = 0;
aad0947 [PATCH] move kallsyms data to .rodata
Jan Beulich authored
92 const u8 *tptr, *data;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
93
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
94 /* Get the compressed symbol length from the first symbol byte. */
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
95 data = &kallsyms_names[off];
96 len = *data;
97 data++;
98
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
99 /*
100 * Update the offset to return the offset for the next symbol on
101 * the compressed stream.
102 */
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
103 off += len + 1;
104
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
105 /*
106 * For every byte on the compressed symbol data, copy the table
107 * entry for that byte.
108 */
109 while (len) {
110 tptr = &kallsyms_token_table[kallsyms_token_index[*data]];
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
111 data++;
112 len--;
113
114 while (*tptr) {
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
115 if (skipped_first) {
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
116 *result = *tptr;
117 result++;
118 } else
119 skipped_first = 1;
120 tptr++;
121 }
122 }
123
124 *result = '\0';
125
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
126 /* Return to offset to the next symbol. */
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
127 return off;
128 }
129
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
130 /*
131 * Get symbol type information. This is encoded as a single char at the
132 * beginning of the symbol name.
133 */
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
134 static char kallsyms_get_symbol_type(unsigned int off)
135 {
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
136 /*
137 * Get just the first code, look it up in the token table,
138 * and return the first char from this token.
139 */
140 return kallsyms_token_table[kallsyms_token_index[kallsyms_names[off + 1]]];
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
141 }
142
143
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
144 /*
145 * Find the offset on the compressed stream given and index in the
146 * kallsyms array.
147 */
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
148 static unsigned int get_symbol_offset(unsigned long pos)
149 {
aad0947 [PATCH] move kallsyms data to .rodata
Jan Beulich authored
150 const u8 *name;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
151 int i;
152
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
153 /*
154 * Use the closest marker we have. We have markers every 256 positions,
155 * so that should be close enough.
156 */
157 name = &kallsyms_names[kallsyms_markers[pos >> 8]];
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
158
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
159 /*
160 * Sequentially scan all the symbols up to the point we're searching
161 * for. Every symbol is stored in a [<len>][<len> bytes of data] format,
162 * so we just need to add the len to the current pointer for every
163 * symbol we wish to skip.
164 */
165 for (i = 0; i < (pos & 0xFF); i++)
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
166 name = name + (*name) + 1;
167
168 return name - kallsyms_names;
169 }
170
171 /* Lookup the address for this symbol. Returns 0 if not found. */
172 unsigned long kallsyms_lookup_name(const char *name)
173 {
9281ace @htejun kallsyms: make KSYM_NAME_LEN include space for trailing '\0'
htejun authored
174 char namebuf[KSYM_NAME_LEN];
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
175 unsigned long i;
176 unsigned int off;
177
178 for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
179 off = kallsyms_expand_symbol(off, namebuf);
180
181 if (strcmp(namebuf, name) == 0)
182 return kallsyms_addresses[i];
183 }
184 return module_kallsyms_lookup_name(name);
185 }
f60d24d @fweisbec hw-breakpoints: Fix broken hw-breakpoint sample module
fweisbec authored
186 EXPORT_SYMBOL_GPL(kallsyms_lookup_name);
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
187
75a6661 @andersk Ksplice: Add functions for walking kallsyms symbols
andersk authored
188 int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
189 unsigned long),
190 void *data)
191 {
192 char namebuf[KSYM_NAME_LEN];
193 unsigned long i;
194 unsigned int off;
195 int ret;
196
197 for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
198 off = kallsyms_expand_symbol(off, namebuf);
199 ret = fn(data, namebuf, NULL, kallsyms_addresses[i]);
200 if (ret != 0)
201 return ret;
202 }
203 return module_kallsyms_on_each_symbol(fn, data);
204 }
205 EXPORT_SYMBOL_GPL(kallsyms_on_each_symbol);
206
ffc5089 [PATCH] Create kallsyms_lookup_size_offset()
Franck Bui-Huu authored
207 static unsigned long get_symbol_pos(unsigned long addr,
208 unsigned long *symbolsize,
209 unsigned long *offset)
210 {
211 unsigned long symbol_start = 0, symbol_end = 0;
212 unsigned long i, low, high, mid;
213
2ea0389 Revert "kbuild: strip generated symbols from *.ko"
Sam Ravnborg authored
214 /* This kernel should never had been booted. */
215 BUG_ON(!kallsyms_addresses);
216
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
217 /* Do a binary search on the sorted kallsyms_addresses array. */
ffc5089 [PATCH] Create kallsyms_lookup_size_offset()
Franck Bui-Huu authored
218 low = 0;
219 high = kallsyms_num_syms;
220
221 while (high - low > 1) {
2fc9c4e @vegard kallsyms: fix potential overflow in binary search
vegard authored
222 mid = low + (high - low) / 2;
ffc5089 [PATCH] Create kallsyms_lookup_size_offset()
Franck Bui-Huu authored
223 if (kallsyms_addresses[mid] <= addr)
224 low = mid;
225 else
226 high = mid;
227 }
228
229 /*
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
230 * Search for the first aliased symbol. Aliased
231 * symbols are symbols with the same address.
ffc5089 [PATCH] Create kallsyms_lookup_size_offset()
Franck Bui-Huu authored
232 */
233 while (low && kallsyms_addresses[low-1] == kallsyms_addresses[low])
234 --low;
235
236 symbol_start = kallsyms_addresses[low];
237
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
238 /* Search for next non-aliased symbol. */
ffc5089 [PATCH] Create kallsyms_lookup_size_offset()
Franck Bui-Huu authored
239 for (i = low + 1; i < kallsyms_num_syms; i++) {
240 if (kallsyms_addresses[i] > symbol_start) {
241 symbol_end = kallsyms_addresses[i];
242 break;
243 }
244 }
245
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
246 /* If we found no next symbol, we use the end of the section. */
ffc5089 [PATCH] Create kallsyms_lookup_size_offset()
Franck Bui-Huu authored
247 if (!symbol_end) {
248 if (is_kernel_inittext(addr))
249 symbol_end = (unsigned long)_einittext;
250 else if (all_var)
251 symbol_end = (unsigned long)_end;
252 else
253 symbol_end = (unsigned long)_etext;
254 }
255
ffb4512 Simplify kallsyms_lookup()
Alexey Dobriyan authored
256 if (symbolsize)
257 *symbolsize = symbol_end - symbol_start;
258 if (offset)
259 *offset = addr - symbol_start;
ffc5089 [PATCH] Create kallsyms_lookup_size_offset()
Franck Bui-Huu authored
260
261 return low;
262 }
263
264 /*
265 * Lookup an address but don't bother to find any names.
266 */
267 int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize,
268 unsigned long *offset)
269 {
6dd06c9 @rustyrussell module: make module_address_lookup safe
rustyrussell authored
270 char namebuf[KSYM_NAME_LEN];
ffc5089 [PATCH] Create kallsyms_lookup_size_offset()
Franck Bui-Huu authored
271 if (is_ksym_addr(addr))
272 return !!get_symbol_pos(addr, symbolsize, offset);
273
6dd06c9 @rustyrussell module: make module_address_lookup safe
rustyrussell authored
274 return !!module_address_lookup(addr, symbolsize, offset, NULL, namebuf);
ffc5089 [PATCH] Create kallsyms_lookup_size_offset()
Franck Bui-Huu authored
275 }
276
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
277 /*
278 * Lookup an address
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
279 * - modname is set to NULL if it's in the kernel.
280 * - We guarantee that the returned name is valid until we reschedule even if.
281 * It resides in a module.
282 * - We also guarantee that modname will be valid until rescheduled.
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
283 */
284 const char *kallsyms_lookup(unsigned long addr,
285 unsigned long *symbolsize,
286 unsigned long *offset,
287 char **modname, char *namebuf)
288 {
9281ace @htejun kallsyms: make KSYM_NAME_LEN include space for trailing '\0'
htejun authored
289 namebuf[KSYM_NAME_LEN - 1] = 0;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
290 namebuf[0] = 0;
291
ffc5089 [PATCH] Create kallsyms_lookup_size_offset()
Franck Bui-Huu authored
292 if (is_ksym_addr(addr)) {
293 unsigned long pos;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
294
ffc5089 [PATCH] Create kallsyms_lookup_size_offset()
Franck Bui-Huu authored
295 pos = get_symbol_pos(addr, symbolsize, offset);
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
296 /* Grab name */
ffc5089 [PATCH] Create kallsyms_lookup_size_offset()
Franck Bui-Huu authored
297 kallsyms_expand_symbol(get_symbol_offset(pos), namebuf);
7a74fc4 fix possible null ptr deref in kallsyms_lookup
Kyle McMartin authored
298 if (modname)
299 *modname = NULL;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
300 return namebuf;
301 }
302
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
303 /* See if it's in a module. */
6dd06c9 @rustyrussell module: make module_address_lookup safe
rustyrussell authored
304 return module_address_lookup(addr, symbolsize, offset, modname,
305 namebuf);
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
306 }
307
9d65cb4 Fix race between cat /proc/*/wchan and rmmod et al
Alexey Dobriyan authored
308 int lookup_symbol_name(unsigned long addr, char *symname)
309 {
310 symname[0] = '\0';
9281ace @htejun kallsyms: make KSYM_NAME_LEN include space for trailing '\0'
htejun authored
311 symname[KSYM_NAME_LEN - 1] = '\0';
9d65cb4 Fix race between cat /proc/*/wchan and rmmod et al
Alexey Dobriyan authored
312
313 if (is_ksym_addr(addr)) {
314 unsigned long pos;
315
316 pos = get_symbol_pos(addr, NULL, NULL);
317 /* Grab name */
318 kallsyms_expand_symbol(get_symbol_offset(pos), symname);
319 return 0;
320 }
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
321 /* See if it's in a module. */
9d65cb4 Fix race between cat /proc/*/wchan and rmmod et al
Alexey Dobriyan authored
322 return lookup_module_symbol_name(addr, symname);
323 }
324
a5c43da Fix race between cat /proc/slab_allocators and rmmod
Alexey Dobriyan authored
325 int lookup_symbol_attrs(unsigned long addr, unsigned long *size,
326 unsigned long *offset, char *modname, char *name)
327 {
328 name[0] = '\0';
9281ace @htejun kallsyms: make KSYM_NAME_LEN include space for trailing '\0'
htejun authored
329 name[KSYM_NAME_LEN - 1] = '\0';
a5c43da Fix race between cat /proc/slab_allocators and rmmod
Alexey Dobriyan authored
330
331 if (is_ksym_addr(addr)) {
332 unsigned long pos;
333
334 pos = get_symbol_pos(addr, size, offset);
335 /* Grab name */
336 kallsyms_expand_symbol(get_symbol_offset(pos), name);
337 modname[0] = '\0';
338 return 0;
339 }
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
340 /* See if it's in a module. */
a5c43da Fix race between cat /proc/slab_allocators and rmmod
Alexey Dobriyan authored
341 return lookup_module_symbol_attrs(addr, size, offset, modname, name);
342 }
343
42e3808 Extend print_symbol capability
Robert Peterson authored
344 /* Look up a kernel symbol and return it in a text buffer. */
0f77a8d @namhyung vsprintf: Introduce %pB format specifier
namhyung authored
345 static int __sprint_symbol(char *buffer, unsigned long address,
4796dd2 @bebarino vsprintf: fix %ps on non symbols when using kallsyms
bebarino authored
346 int symbol_offset, int add_offset)
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
347 {
348 char *modname;
349 const char *name;
350 unsigned long offset, size;
966c8c1 sprint_symbol(): use less stack
Hugh Dickins authored
351 int len;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
352
0f77a8d @namhyung vsprintf: Introduce %pB format specifier
namhyung authored
353 address += symbol_offset;
966c8c1 sprint_symbol(): use less stack
Hugh Dickins authored
354 name = kallsyms_lookup(address, &size, &offset, &modname, buffer);
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
355 if (!name)
42e3808 Extend print_symbol capability
Robert Peterson authored
356 return sprintf(buffer, "0x%lx", address);
19769b7 sprint_symbol() cleanup
Andrew Morton authored
357
966c8c1 sprint_symbol(): use less stack
Hugh Dickins authored
358 if (name != buffer)
359 strcpy(buffer, name);
360 len = strlen(buffer);
0f77a8d @namhyung vsprintf: Introduce %pB format specifier
namhyung authored
361 offset -= symbol_offset;
966c8c1 sprint_symbol(): use less stack
Hugh Dickins authored
362
4796dd2 @bebarino vsprintf: fix %ps on non symbols when using kallsyms
bebarino authored
363 if (add_offset)
364 len += sprintf(buffer + len, "+%#lx/%#lx", offset, size);
365
19769b7 sprint_symbol() cleanup
Andrew Morton authored
366 if (modname)
4796dd2 @bebarino vsprintf: fix %ps on non symbols when using kallsyms
bebarino authored
367 len += sprintf(buffer + len, " [%s]", modname);
966c8c1 sprint_symbol(): use less stack
Hugh Dickins authored
368
369 return len;
42e3808 Extend print_symbol capability
Robert Peterson authored
370 }
0f77a8d @namhyung vsprintf: Introduce %pB format specifier
namhyung authored
371
372 /**
373 * sprint_symbol - Look up a kernel symbol and return it in a text buffer
374 * @buffer: buffer to be stored
375 * @address: address to lookup
376 *
377 * This function looks up a kernel symbol with @address and stores its name,
378 * offset, size and module name to @buffer if possible. If no symbol was found,
379 * just saves its @address as is.
380 *
381 * This function returns the number of bytes stored in @buffer.
382 */
383 int sprint_symbol(char *buffer, unsigned long address)
384 {
4796dd2 @bebarino vsprintf: fix %ps on non symbols when using kallsyms
bebarino authored
385 return __sprint_symbol(buffer, address, 0, 1);
0f77a8d @namhyung vsprintf: Introduce %pB format specifier
namhyung authored
386 }
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
387 EXPORT_SYMBOL_GPL(sprint_symbol);
42e3808 Extend print_symbol capability
Robert Peterson authored
388
0f77a8d @namhyung vsprintf: Introduce %pB format specifier
namhyung authored
389 /**
4796dd2 @bebarino vsprintf: fix %ps on non symbols when using kallsyms
bebarino authored
390 * sprint_symbol_no_offset - Look up a kernel symbol and return it in a text buffer
391 * @buffer: buffer to be stored
392 * @address: address to lookup
393 *
394 * This function looks up a kernel symbol with @address and stores its name
395 * and module name to @buffer if possible. If no symbol was found, just saves
396 * its @address as is.
397 *
398 * This function returns the number of bytes stored in @buffer.
399 */
400 int sprint_symbol_no_offset(char *buffer, unsigned long address)
401 {
402 return __sprint_symbol(buffer, address, 0, 0);
403 }
404 EXPORT_SYMBOL_GPL(sprint_symbol_no_offset);
405
406 /**
0f77a8d @namhyung vsprintf: Introduce %pB format specifier
namhyung authored
407 * sprint_backtrace - Look up a backtrace symbol and return it in a text buffer
408 * @buffer: buffer to be stored
409 * @address: address to lookup
410 *
411 * This function is for stack backtrace and does the same thing as
412 * sprint_symbol() but with modified/decreased @address. If there is a
413 * tail-call to the function marked "noreturn", gcc optimized out code after
414 * the call so that the stack-saved return address could point outside of the
415 * caller. This function ensures that kallsyms will find the original caller
416 * by decreasing @address.
417 *
418 * This function returns the number of bytes stored in @buffer.
419 */
420 int sprint_backtrace(char *buffer, unsigned long address)
421 {
4796dd2 @bebarino vsprintf: fix %ps on non symbols when using kallsyms
bebarino authored
422 return __sprint_symbol(buffer, address, -1, 1);
0f77a8d @namhyung vsprintf: Introduce %pB format specifier
namhyung authored
423 }
424
42e3808 Extend print_symbol capability
Robert Peterson authored
425 /* Look up a kernel symbol and print it to the kernel messages. */
426 void __print_symbol(const char *fmt, unsigned long address)
427 {
428 char buffer[KSYM_SYMBOL_LEN];
429
430 sprint_symbol(buffer, address);
431
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
432 printk(fmt, buffer);
433 }
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
434 EXPORT_SYMBOL(__print_symbol);
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
435
436 /* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
437 struct kallsym_iter {
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
438 loff_t pos;
439 unsigned long value;
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
440 unsigned int nameoff; /* If iterating in core kernel symbols. */
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
441 char type;
9281ace @htejun kallsyms: make KSYM_NAME_LEN include space for trailing '\0'
htejun authored
442 char name[KSYM_NAME_LEN];
443 char module_name[MODULE_NAME_LEN];
ea07890 Fix race between rmmod and cat /proc/kallsyms
Alexey Dobriyan authored
444 int exported;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
445 };
446
447 static int get_ksymbol_mod(struct kallsym_iter *iter)
448 {
ea07890 Fix race between rmmod and cat /proc/kallsyms
Alexey Dobriyan authored
449 if (module_get_kallsym(iter->pos - kallsyms_num_syms, &iter->value,
450 &iter->type, iter->name, iter->module_name,
451 &iter->exported) < 0)
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
452 return 0;
453 return 1;
454 }
455
456 /* Returns space to next name. */
457 static unsigned long get_ksymbol_core(struct kallsym_iter *iter)
458 {
459 unsigned off = iter->nameoff;
460
ea07890 Fix race between rmmod and cat /proc/kallsyms
Alexey Dobriyan authored
461 iter->module_name[0] = '\0';
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
462 iter->value = kallsyms_addresses[iter->pos];
463
464 iter->type = kallsyms_get_symbol_type(off);
465
466 off = kallsyms_expand_symbol(off, iter->name);
467
468 return off - iter->nameoff;
469 }
470
471 static void reset_iter(struct kallsym_iter *iter, loff_t new_pos)
472 {
473 iter->name[0] = '\0';
474 iter->nameoff = get_symbol_offset(new_pos);
475 iter->pos = new_pos;
476 }
477
478 /* Returns false if pos at or past end of file. */
479 static int update_iter(struct kallsym_iter *iter, loff_t pos)
480 {
481 /* Module symbols can be accessed randomly. */
482 if (pos >= kallsyms_num_syms) {
483 iter->pos = pos;
484 return get_ksymbol_mod(iter);
485 }
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
486
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
487 /* If we're not on the desired position, reset to new position. */
488 if (pos != iter->pos)
489 reset_iter(iter, pos);
490
491 iter->nameoff += get_ksymbol_core(iter);
492 iter->pos++;
493
494 return 1;
495 }
496
497 static void *s_next(struct seq_file *m, void *p, loff_t *pos)
498 {
499 (*pos)++;
500
501 if (!update_iter(m->private, *pos))
502 return NULL;
503 return p;
504 }
505
506 static void *s_start(struct seq_file *m, loff_t *pos)
507 {
508 if (!update_iter(m->private, *pos))
509 return NULL;
510 return m->private;
511 }
512
513 static void s_stop(struct seq_file *m, void *p)
514 {
515 }
516
517 static int s_show(struct seq_file *m, void *p)
518 {
519 struct kallsym_iter *iter = m->private;
520
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
521 /* Some debugging symbols have no name. Ignore them. */
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
522 if (!iter->name[0])
523 return 0;
524
ea07890 Fix race between rmmod and cat /proc/kallsyms
Alexey Dobriyan authored
525 if (iter->module_name[0]) {
526 char type;
527
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
528 /*
529 * Label it "global" if it is exported,
530 * "local" if not exported.
531 */
ea07890 Fix race between rmmod and cat /proc/kallsyms
Alexey Dobriyan authored
532 type = iter->exported ? toupper(iter->type) :
533 tolower(iter->type);
9f36e2c printk: use %pK for /proc/kallsyms and /proc/modules
Kees Cook authored
534 seq_printf(m, "%pK %c %s\t[%s]\n", (void *)iter->value,
535 type, iter->name, iter->module_name);
ea07890 Fix race between rmmod and cat /proc/kallsyms
Alexey Dobriyan authored
536 } else
9f36e2c printk: use %pK for /proc/kallsyms and /proc/modules
Kees Cook authored
537 seq_printf(m, "%pK %c %s\n", (void *)iter->value,
538 iter->type, iter->name);
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
539 return 0;
540 }
541
15ad7cd [PATCH] struct seq_operations and struct file_operations constification
Helge Deller authored
542 static const struct seq_operations kallsyms_op = {
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
543 .start = s_start,
544 .next = s_next,
545 .stop = s_stop,
546 .show = s_show
547 };
548
549 static int kallsyms_open(struct inode *inode, struct file *file)
550 {
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
551 /*
552 * We keep iterator in m->private, since normal case is to
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
553 * s_start from where we left off, so we avoid doing
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
554 * using get_symbol_offset for every symbol.
555 */
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
556 struct kallsym_iter *iter;
557 int ret;
558
559 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
560 if (!iter)
561 return -ENOMEM;
562 reset_iter(iter, 0);
563
564 ret = seq_open(file, &kallsyms_op);
565 if (ret == 0)
566 ((struct seq_file *)file->private_data)->private = iter;
567 else
568 kfree(iter);
569 return ret;
570 }
571
67fc4e0 @jwessel kdb: core for kgdb back end (2 of 2)
jwessel authored
572 #ifdef CONFIG_KGDB_KDB
573 const char *kdb_walk_kallsyms(loff_t *pos)
574 {
575 static struct kallsym_iter kdb_walk_kallsyms_iter;
576 if (*pos == 0) {
577 memset(&kdb_walk_kallsyms_iter, 0,
578 sizeof(kdb_walk_kallsyms_iter));
579 reset_iter(&kdb_walk_kallsyms_iter, 0);
580 }
581 while (1) {
582 if (!update_iter(&kdb_walk_kallsyms_iter, *pos))
583 return NULL;
584 ++*pos;
585 /* Some debugging symbols have no name. Ignore them. */
586 if (kdb_walk_kallsyms_iter.name[0])
587 return kdb_walk_kallsyms_iter.name;
588 }
589 }
590 #endif /* CONFIG_KGDB_KDB */
591
15ad7cd [PATCH] struct seq_operations and struct file_operations constification
Helge Deller authored
592 static const struct file_operations kallsyms_operations = {
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
593 .open = kallsyms_open,
594 .read = seq_read,
595 .llseek = seq_lseek,
5a0c6a0 kallsyms: cleanup: use seq_release_private() where appropriate
Martin Peschke authored
596 .release = seq_release_private,
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
597 };
598
599 static int __init kallsyms_init(void)
600 {
33e0d57 @torvalds Revert "kernel: make /proc/kallsyms mode 400 to reduce ease of attack…
authored
601 proc_create("kallsyms", 0444, NULL, &kallsyms_operations);
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
602 return 0;
603 }
ad6ccfa @mkatiyar kernel/kallsyms.c: replace deprecated __initcall with device_initcall…
mkatiyar authored
604 device_initcall(kallsyms_init);
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