Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/kernel/kallsyms.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
File MIME type: text/plain
File size: 10606 byte(s)
Tag kernel26-2.6.12-alx-r9
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> |
21 | #include <linux/mm.h> |
22 | |
23 | #include <asm/sections.h> |
24 | |
25 | #ifdef CONFIG_KALLSYMS_ALL |
26 | #define all_var 1 |
27 | #else |
28 | #define all_var 0 |
29 | #endif |
30 | |
31 | /* These will be re-linked against their real values during the second link stage */ |
32 | extern unsigned long kallsyms_addresses[] __attribute__((weak)); |
33 | extern unsigned long kallsyms_num_syms __attribute__((weak,section("data"))); |
34 | extern u8 kallsyms_names[] __attribute__((weak)); |
35 | |
36 | extern u8 kallsyms_token_table[] __attribute__((weak)); |
37 | extern u16 kallsyms_token_index[] __attribute__((weak)); |
38 | |
39 | extern unsigned long kallsyms_markers[] __attribute__((weak)); |
40 | |
41 | static inline int is_kernel_inittext(unsigned long addr) |
42 | { |
43 | if (addr >= (unsigned long)_sinittext |
44 | && addr <= (unsigned long)_einittext) |
45 | return 1; |
46 | return 0; |
47 | } |
48 | |
49 | static inline int is_kernel_extratext(unsigned long addr) |
50 | { |
51 | if (addr >= (unsigned long)_sextratext |
52 | && addr <= (unsigned long)_eextratext) |
53 | return 1; |
54 | return 0; |
55 | } |
56 | |
57 | static inline int is_kernel_text(unsigned long addr) |
58 | { |
59 | if (addr >= (unsigned long)_stext && addr <= (unsigned long)_etext) |
60 | return 1; |
61 | return in_gate_area_no_task(addr); |
62 | } |
63 | |
64 | static inline int is_kernel(unsigned long addr) |
65 | { |
66 | if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end) |
67 | return 1; |
68 | return in_gate_area_no_task(addr); |
69 | } |
70 | |
71 | /* expand a compressed symbol data into the resulting uncompressed string, |
72 | given the offset to where the symbol is in the compressed stream */ |
73 | static unsigned int kallsyms_expand_symbol(unsigned int off, char *result) |
74 | { |
75 | int len, skipped_first = 0; |
76 | u8 *tptr, *data; |
77 | |
78 | /* get the compressed symbol length from the first symbol byte */ |
79 | data = &kallsyms_names[off]; |
80 | len = *data; |
81 | data++; |
82 | |
83 | /* update the offset to return the offset for the next symbol on |
84 | * the compressed stream */ |
85 | off += len + 1; |
86 | |
87 | /* for every byte on the compressed symbol data, copy the table |
88 | entry for that byte */ |
89 | while(len) { |
90 | tptr = &kallsyms_token_table[ kallsyms_token_index[*data] ]; |
91 | data++; |
92 | len--; |
93 | |
94 | while (*tptr) { |
95 | if(skipped_first) { |
96 | *result = *tptr; |
97 | result++; |
98 | } else |
99 | skipped_first = 1; |
100 | tptr++; |
101 | } |
102 | } |
103 | |
104 | *result = '\0'; |
105 | |
106 | /* return to offset to the next symbol */ |
107 | return off; |
108 | } |
109 | |
110 | /* get symbol type information. This is encoded as a single char at the |
111 | * begining of the symbol name */ |
112 | static char kallsyms_get_symbol_type(unsigned int off) |
113 | { |
114 | /* get just the first code, look it up in the token table, and return the |
115 | * first char from this token */ |
116 | return kallsyms_token_table[ kallsyms_token_index[ kallsyms_names[off+1] ] ]; |
117 | } |
118 | |
119 | |
120 | /* find the offset on the compressed stream given and index in the |
121 | * kallsyms array */ |
122 | static unsigned int get_symbol_offset(unsigned long pos) |
123 | { |
124 | u8 *name; |
125 | int i; |
126 | |
127 | /* use the closest marker we have. We have markers every 256 positions, |
128 | * so that should be close enough */ |
129 | name = &kallsyms_names[ kallsyms_markers[pos>>8] ]; |
130 | |
131 | /* sequentially scan all the symbols up to the point we're searching for. |
132 | * Every symbol is stored in a [<len>][<len> bytes of data] format, so we |
133 | * just need to add the len to the current pointer for every symbol we |
134 | * wish to skip */ |
135 | for(i = 0; i < (pos&0xFF); i++) |
136 | name = name + (*name) + 1; |
137 | |
138 | return name - kallsyms_names; |
139 | } |
140 | |
141 | /* Lookup the address for this symbol. Returns 0 if not found. */ |
142 | unsigned long kallsyms_lookup_name(const char *name) |
143 | { |
144 | char namebuf[KSYM_NAME_LEN+1]; |
145 | unsigned long i; |
146 | unsigned int off; |
147 | |
148 | for (i = 0, off = 0; i < kallsyms_num_syms; i++) { |
149 | off = kallsyms_expand_symbol(off, namebuf); |
150 | |
151 | if (strcmp(namebuf, name) == 0) |
152 | return kallsyms_addresses[i]; |
153 | } |
154 | return module_kallsyms_lookup_name(name); |
155 | } |
156 | EXPORT_SYMBOL_GPL(kallsyms_lookup_name); |
157 | |
158 | /* |
159 | * Lookup an address |
160 | * - modname is set to NULL if it's in the kernel |
161 | * - we guarantee that the returned name is valid until we reschedule even if |
162 | * it resides in a module |
163 | * - we also guarantee that modname will be valid until rescheduled |
164 | */ |
165 | const char *kallsyms_lookup(unsigned long addr, |
166 | unsigned long *symbolsize, |
167 | unsigned long *offset, |
168 | char **modname, char *namebuf) |
169 | { |
170 | unsigned long i, low, high, mid; |
171 | const char *msym; |
172 | |
173 | /* This kernel should never had been booted. */ |
174 | BUG_ON(!kallsyms_addresses); |
175 | |
176 | namebuf[KSYM_NAME_LEN] = 0; |
177 | namebuf[0] = 0; |
178 | |
179 | if ((all_var && is_kernel(addr)) || |
180 | (!all_var && (is_kernel_text(addr) || is_kernel_inittext(addr) || |
181 | is_kernel_extratext(addr)))) { |
182 | unsigned long symbol_end = 0; |
183 | |
184 | /* do a binary search on the sorted kallsyms_addresses array */ |
185 | low = 0; |
186 | high = kallsyms_num_syms; |
187 | |
188 | while (high-low > 1) { |
189 | mid = (low + high) / 2; |
190 | if (kallsyms_addresses[mid] <= addr) low = mid; |
191 | else high = mid; |
192 | } |
193 | |
194 | /* search for the first aliased symbol. Aliased symbols are |
195 | symbols with the same address */ |
196 | while (low && kallsyms_addresses[low - 1] == kallsyms_addresses[low]) |
197 | --low; |
198 | |
199 | /* Grab name */ |
200 | kallsyms_expand_symbol(get_symbol_offset(low), namebuf); |
201 | |
202 | /* Search for next non-aliased symbol */ |
203 | for (i = low + 1; i < kallsyms_num_syms; i++) { |
204 | if (kallsyms_addresses[i] > kallsyms_addresses[low]) { |
205 | symbol_end = kallsyms_addresses[i]; |
206 | break; |
207 | } |
208 | } |
209 | |
210 | /* if we found no next symbol, we use the end of the section */ |
211 | if (!symbol_end) { |
212 | if (is_kernel_inittext(addr)) |
213 | symbol_end = (unsigned long)_einittext; |
214 | else |
215 | symbol_end = all_var ? (unsigned long)_end : (unsigned long)_etext; |
216 | } |
217 | |
218 | *symbolsize = symbol_end - kallsyms_addresses[low]; |
219 | *modname = NULL; |
220 | *offset = addr - kallsyms_addresses[low]; |
221 | return namebuf; |
222 | } |
223 | |
224 | /* see if it's in a module */ |
225 | msym = module_address_lookup(addr, symbolsize, offset, modname); |
226 | if (msym) |
227 | return strncpy(namebuf, msym, KSYM_NAME_LEN); |
228 | |
229 | return NULL; |
230 | } |
231 | |
232 | /* Replace "%s" in format with address, or returns -errno. */ |
233 | void __print_symbol(const char *fmt, unsigned long address) |
234 | { |
235 | char *modname; |
236 | const char *name; |
237 | unsigned long offset, size; |
238 | char namebuf[KSYM_NAME_LEN+1]; |
239 | char buffer[sizeof("%s+%#lx/%#lx [%s]") + KSYM_NAME_LEN + |
240 | 2*(BITS_PER_LONG*3/10) + MODULE_NAME_LEN + 1]; |
241 | |
242 | name = kallsyms_lookup(address, &size, &offset, &modname, namebuf); |
243 | |
244 | if (!name) |
245 | sprintf(buffer, "0x%lx", address); |
246 | else { |
247 | if (modname) |
248 | sprintf(buffer, "%s+%#lx/%#lx [%s]", name, offset, |
249 | size, modname); |
250 | else |
251 | sprintf(buffer, "%s+%#lx/%#lx", name, offset, size); |
252 | } |
253 | printk(fmt, buffer); |
254 | } |
255 | |
256 | /* To avoid using get_symbol_offset for every symbol, we carry prefix along. */ |
257 | struct kallsym_iter |
258 | { |
259 | loff_t pos; |
260 | struct module *owner; |
261 | unsigned long value; |
262 | unsigned int nameoff; /* If iterating in core kernel symbols */ |
263 | char type; |
264 | char name[KSYM_NAME_LEN+1]; |
265 | }; |
266 | |
267 | /* Only label it "global" if it is exported. */ |
268 | static void upcase_if_global(struct kallsym_iter *iter) |
269 | { |
270 | if (is_exported(iter->name, iter->owner)) |
271 | iter->type += 'A' - 'a'; |
272 | } |
273 | |
274 | static int get_ksymbol_mod(struct kallsym_iter *iter) |
275 | { |
276 | iter->owner = module_get_kallsym(iter->pos - kallsyms_num_syms, |
277 | &iter->value, |
278 | &iter->type, iter->name); |
279 | if (iter->owner == NULL) |
280 | return 0; |
281 | |
282 | upcase_if_global(iter); |
283 | return 1; |
284 | } |
285 | |
286 | /* Returns space to next name. */ |
287 | static unsigned long get_ksymbol_core(struct kallsym_iter *iter) |
288 | { |
289 | unsigned off = iter->nameoff; |
290 | |
291 | iter->owner = NULL; |
292 | iter->value = kallsyms_addresses[iter->pos]; |
293 | |
294 | iter->type = kallsyms_get_symbol_type(off); |
295 | |
296 | off = kallsyms_expand_symbol(off, iter->name); |
297 | |
298 | return off - iter->nameoff; |
299 | } |
300 | |
301 | static void reset_iter(struct kallsym_iter *iter, loff_t new_pos) |
302 | { |
303 | iter->name[0] = '\0'; |
304 | iter->nameoff = get_symbol_offset(new_pos); |
305 | iter->pos = new_pos; |
306 | } |
307 | |
308 | /* Returns false if pos at or past end of file. */ |
309 | static int update_iter(struct kallsym_iter *iter, loff_t pos) |
310 | { |
311 | /* Module symbols can be accessed randomly. */ |
312 | if (pos >= kallsyms_num_syms) { |
313 | iter->pos = pos; |
314 | return get_ksymbol_mod(iter); |
315 | } |
316 | |
317 | /* If we're not on the desired position, reset to new position. */ |
318 | if (pos != iter->pos) |
319 | reset_iter(iter, pos); |
320 | |
321 | iter->nameoff += get_ksymbol_core(iter); |
322 | iter->pos++; |
323 | |
324 | return 1; |
325 | } |
326 | |
327 | static void *s_next(struct seq_file *m, void *p, loff_t *pos) |
328 | { |
329 | (*pos)++; |
330 | |
331 | if (!update_iter(m->private, *pos)) |
332 | return NULL; |
333 | return p; |
334 | } |
335 | |
336 | static void *s_start(struct seq_file *m, loff_t *pos) |
337 | { |
338 | if (!update_iter(m->private, *pos)) |
339 | return NULL; |
340 | return m->private; |
341 | } |
342 | |
343 | static void s_stop(struct seq_file *m, void *p) |
344 | { |
345 | } |
346 | |
347 | static int s_show(struct seq_file *m, void *p) |
348 | { |
349 | struct kallsym_iter *iter = m->private; |
350 | |
351 | /* Some debugging symbols have no name. Ignore them. */ |
352 | if (!iter->name[0]) |
353 | return 0; |
354 | |
355 | if (iter->owner) |
356 | seq_printf(m, "%0*lx %c %s\t[%s]\n", |
357 | (int)(2*sizeof(void*)), |
358 | iter->value, iter->type, iter->name, |
359 | module_name(iter->owner)); |
360 | else |
361 | seq_printf(m, "%0*lx %c %s\n", |
362 | (int)(2*sizeof(void*)), |
363 | iter->value, iter->type, iter->name); |
364 | return 0; |
365 | } |
366 | |
367 | static struct seq_operations kallsyms_op = { |
368 | .start = s_start, |
369 | .next = s_next, |
370 | .stop = s_stop, |
371 | .show = s_show |
372 | }; |
373 | |
374 | static int kallsyms_open(struct inode *inode, struct file *file) |
375 | { |
376 | /* We keep iterator in m->private, since normal case is to |
377 | * s_start from where we left off, so we avoid doing |
378 | * using get_symbol_offset for every symbol */ |
379 | struct kallsym_iter *iter; |
380 | int ret; |
381 | |
382 | iter = kmalloc(sizeof(*iter), GFP_KERNEL); |
383 | if (!iter) |
384 | return -ENOMEM; |
385 | reset_iter(iter, 0); |
386 | |
387 | ret = seq_open(file, &kallsyms_op); |
388 | if (ret == 0) |
389 | ((struct seq_file *)file->private_data)->private = iter; |
390 | else |
391 | kfree(iter); |
392 | return ret; |
393 | } |
394 | |
395 | static int kallsyms_release(struct inode *inode, struct file *file) |
396 | { |
397 | struct seq_file *m = (struct seq_file *)file->private_data; |
398 | kfree(m->private); |
399 | return seq_release(inode, file); |
400 | } |
401 | |
402 | static struct file_operations kallsyms_operations = { |
403 | .open = kallsyms_open, |
404 | .read = seq_read, |
405 | .llseek = seq_lseek, |
406 | .release = kallsyms_release, |
407 | }; |
408 | |
409 | static int __init kallsyms_init(void) |
410 | { |
411 | struct proc_dir_entry *entry; |
412 | |
413 | entry = create_proc_entry("kallsyms", 0444, NULL); |
414 | if (entry) |
415 | entry->proc_fops = &kallsyms_operations; |
416 | return 0; |
417 | } |
418 | __initcall(kallsyms_init); |
419 | |
420 | EXPORT_SYMBOL(__print_symbol); |