ASoC: soc-cache: Introduce raw bulk write support
[linux-2.6.git] / kernel / kallsyms.c
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
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
35 /*
36  * These will be re-linked against their real values
37  * during the second link stage.
38  */
39 extern const unsigned long kallsyms_addresses[] __attribute__((weak));
40 extern const u8 kallsyms_names[] __attribute__((weak));
41
42 /*
43  * Tell the compiler that the count isn't in the small data section if the arch
44  * has one (eg: FRV).
45  */
46 extern const unsigned long kallsyms_num_syms
47 __attribute__((weak, section(".rodata")));
48
49 extern const u8 kallsyms_token_table[] __attribute__((weak));
50 extern const u16 kallsyms_token_index[] __attribute__((weak));
51
52 extern const unsigned long kallsyms_markers[] __attribute__((weak));
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 {
64         if ((addr >= (unsigned long)_stext && addr <= (unsigned long)_etext) ||
65             arch_is_kernel_text(addr))
66                 return 1;
67         return in_gate_area_no_task(addr);
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;
74         return in_gate_area_no_task(addr);
75 }
76
77 static int is_ksym_addr(unsigned long addr)
78 {
79         if (all_var)
80                 return is_kernel(addr);
81
82         return is_kernel_text(addr) || is_kernel_inittext(addr);
83 }
84
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  */
89 static unsigned int kallsyms_expand_symbol(unsigned int off, char *result)
90 {
91         int len, skipped_first = 0;
92         const u8 *tptr, *data;
93
94         /* Get the compressed symbol length from the first symbol byte. */
95         data = &kallsyms_names[off];
96         len = *data;
97         data++;
98
99         /*
100          * Update the offset to return the offset for the next symbol on
101          * the compressed stream.
102          */
103         off += len + 1;
104
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]];
111                 data++;
112                 len--;
113
114                 while (*tptr) {
115                         if (skipped_first) {
116                                 *result = *tptr;
117                                 result++;
118                         } else
119                                 skipped_first = 1;
120                         tptr++;
121                 }
122         }
123
124         *result = '\0';
125
126         /* Return to offset to the next symbol. */
127         return off;
128 }
129
130 /*
131  * Get symbol type information. This is encoded as a single char at the
132  * beginning of the symbol name.
133  */
134 static char kallsyms_get_symbol_type(unsigned int off)
135 {
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]]];
141 }
142
143
144 /*
145  * Find the offset on the compressed stream given and index in the
146  * kallsyms array.
147  */
148 static unsigned int get_symbol_offset(unsigned long pos)
149 {
150         const u8 *name;
151         int i;
152
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]];
158
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++)
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 {
174         char namebuf[KSYM_NAME_LEN];
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 }
186 EXPORT_SYMBOL_GPL(kallsyms_lookup_name);
187
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
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
214         /* This kernel should never had been booted. */
215         BUG_ON(!kallsyms_addresses);
216
217         /* Do a binary search on the sorted kallsyms_addresses array. */
218         low = 0;
219         high = kallsyms_num_syms;
220
221         while (high - low > 1) {
222                 mid = low + (high - low) / 2;
223                 if (kallsyms_addresses[mid] <= addr)
224                         low = mid;
225                 else
226                         high = mid;
227         }
228
229         /*
230          * Search for the first aliased symbol. Aliased
231          * symbols are symbols with the same address.
232          */
233         while (low && kallsyms_addresses[low-1] == kallsyms_addresses[low])
234                 --low;
235
236         symbol_start = kallsyms_addresses[low];
237
238         /* Search for next non-aliased symbol. */
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
246         /* If we found no next symbol, we use the end of the section. */
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
256         if (symbolsize)
257                 *symbolsize = symbol_end - symbol_start;
258         if (offset)
259                 *offset = addr - symbol_start;
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 {
270         char namebuf[KSYM_NAME_LEN];
271         if (is_ksym_addr(addr))
272                 return !!get_symbol_pos(addr, symbolsize, offset);
273
274         return !!module_address_lookup(addr, symbolsize, offset, NULL, namebuf);
275 }
276
277 /*
278  * Lookup an address
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.
283  */
284 const char *kallsyms_lookup(unsigned long addr,
285                             unsigned long *symbolsize,
286                             unsigned long *offset,
287                             char **modname, char *namebuf)
288 {
289         namebuf[KSYM_NAME_LEN - 1] = 0;
290         namebuf[0] = 0;
291
292         if (is_ksym_addr(addr)) {
293                 unsigned long pos;
294
295                 pos = get_symbol_pos(addr, symbolsize, offset);
296                 /* Grab name */
297                 kallsyms_expand_symbol(get_symbol_offset(pos), namebuf);
298                 if (modname)
299                         *modname = NULL;
300                 return namebuf;
301         }
302
303         /* See if it's in a module. */
304         return module_address_lookup(addr, symbolsize, offset, modname,
305                                      namebuf);
306 }
307
308 int lookup_symbol_name(unsigned long addr, char *symname)
309 {
310         symname[0] = '\0';
311         symname[KSYM_NAME_LEN - 1] = '\0';
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         }
321         /* See if it's in a module. */
322         return lookup_module_symbol_name(addr, symname);
323 }
324
325 int lookup_symbol_attrs(unsigned long addr, unsigned long *size,
326                         unsigned long *offset, char *modname, char *name)
327 {
328         name[0] = '\0';
329         name[KSYM_NAME_LEN - 1] = '\0';
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         }
340         /* See if it's in a module. */
341         return lookup_module_symbol_attrs(addr, size, offset, modname, name);
342 }
343
344 /* Look up a kernel symbol and return it in a text buffer. */
345 int sprint_symbol(char *buffer, unsigned long address)
346 {
347         char *modname;
348         const char *name;
349         unsigned long offset, size;
350         int len;
351
352         name = kallsyms_lookup(address, &size, &offset, &modname, buffer);
353         if (!name)
354                 return sprintf(buffer, "0x%lx", address);
355
356         if (name != buffer)
357                 strcpy(buffer, name);
358         len = strlen(buffer);
359         buffer += len;
360
361         if (modname)
362                 len += sprintf(buffer, "+%#lx/%#lx [%s]",
363                                                 offset, size, modname);
364         else
365                 len += sprintf(buffer, "+%#lx/%#lx", offset, size);
366
367         return len;
368 }
369 EXPORT_SYMBOL_GPL(sprint_symbol);
370
371 /* Look up a kernel symbol and print it to the kernel messages. */
372 void __print_symbol(const char *fmt, unsigned long address)
373 {
374         char buffer[KSYM_SYMBOL_LEN];
375
376         sprint_symbol(buffer, address);
377
378         printk(fmt, buffer);
379 }
380 EXPORT_SYMBOL(__print_symbol);
381
382 /* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
383 struct kallsym_iter {
384         loff_t pos;
385         unsigned long value;
386         unsigned int nameoff; /* If iterating in core kernel symbols. */
387         char type;
388         char name[KSYM_NAME_LEN];
389         char module_name[MODULE_NAME_LEN];
390         int exported;
391 };
392
393 static int get_ksymbol_mod(struct kallsym_iter *iter)
394 {
395         if (module_get_kallsym(iter->pos - kallsyms_num_syms, &iter->value,
396                                 &iter->type, iter->name, iter->module_name,
397                                 &iter->exported) < 0)
398                 return 0;
399         return 1;
400 }
401
402 /* Returns space to next name. */
403 static unsigned long get_ksymbol_core(struct kallsym_iter *iter)
404 {
405         unsigned off = iter->nameoff;
406
407         iter->module_name[0] = '\0';
408         iter->value = kallsyms_addresses[iter->pos];
409
410         iter->type = kallsyms_get_symbol_type(off);
411
412         off = kallsyms_expand_symbol(off, iter->name);
413
414         return off - iter->nameoff;
415 }
416
417 static void reset_iter(struct kallsym_iter *iter, loff_t new_pos)
418 {
419         iter->name[0] = '\0';
420         iter->nameoff = get_symbol_offset(new_pos);
421         iter->pos = new_pos;
422 }
423
424 /* Returns false if pos at or past end of file. */
425 static int update_iter(struct kallsym_iter *iter, loff_t pos)
426 {
427         /* Module symbols can be accessed randomly. */
428         if (pos >= kallsyms_num_syms) {
429                 iter->pos = pos;
430                 return get_ksymbol_mod(iter);
431         }
432
433         /* If we're not on the desired position, reset to new position. */
434         if (pos != iter->pos)
435                 reset_iter(iter, pos);
436
437         iter->nameoff += get_ksymbol_core(iter);
438         iter->pos++;
439
440         return 1;
441 }
442
443 static void *s_next(struct seq_file *m, void *p, loff_t *pos)
444 {
445         (*pos)++;
446
447         if (!update_iter(m->private, *pos))
448                 return NULL;
449         return p;
450 }
451
452 static void *s_start(struct seq_file *m, loff_t *pos)
453 {
454         if (!update_iter(m->private, *pos))
455                 return NULL;
456         return m->private;
457 }
458
459 static void s_stop(struct seq_file *m, void *p)
460 {
461 }
462
463 static int s_show(struct seq_file *m, void *p)
464 {
465         struct kallsym_iter *iter = m->private;
466
467         /* Some debugging symbols have no name.  Ignore them. */
468         if (!iter->name[0])
469                 return 0;
470
471         if (iter->module_name[0]) {
472                 char type;
473
474                 /*
475                  * Label it "global" if it is exported,
476                  * "local" if not exported.
477                  */
478                 type = iter->exported ? toupper(iter->type) :
479                                         tolower(iter->type);
480                 seq_printf(m, "%0*lx %c %s\t[%s]\n",
481                            (int)(2 * sizeof(void *)),
482                            iter->value, type, iter->name, iter->module_name);
483         } else
484                 seq_printf(m, "%0*lx %c %s\n",
485                            (int)(2 * sizeof(void *)),
486                            iter->value, iter->type, iter->name);
487         return 0;
488 }
489
490 static const struct seq_operations kallsyms_op = {
491         .start = s_start,
492         .next = s_next,
493         .stop = s_stop,
494         .show = s_show
495 };
496
497 static int kallsyms_open(struct inode *inode, struct file *file)
498 {
499         /*
500          * We keep iterator in m->private, since normal case is to
501          * s_start from where we left off, so we avoid doing
502          * using get_symbol_offset for every symbol.
503          */
504         struct kallsym_iter *iter;
505         int ret;
506
507         iter = kmalloc(sizeof(*iter), GFP_KERNEL);
508         if (!iter)
509                 return -ENOMEM;
510         reset_iter(iter, 0);
511
512         ret = seq_open(file, &kallsyms_op);
513         if (ret == 0)
514                 ((struct seq_file *)file->private_data)->private = iter;
515         else
516                 kfree(iter);
517         return ret;
518 }
519
520 #ifdef  CONFIG_KGDB_KDB
521 const char *kdb_walk_kallsyms(loff_t *pos)
522 {
523         static struct kallsym_iter kdb_walk_kallsyms_iter;
524         if (*pos == 0) {
525                 memset(&kdb_walk_kallsyms_iter, 0,
526                        sizeof(kdb_walk_kallsyms_iter));
527                 reset_iter(&kdb_walk_kallsyms_iter, 0);
528         }
529         while (1) {
530                 if (!update_iter(&kdb_walk_kallsyms_iter, *pos))
531                         return NULL;
532                 ++*pos;
533                 /* Some debugging symbols have no name.  Ignore them. */
534                 if (kdb_walk_kallsyms_iter.name[0])
535                         return kdb_walk_kallsyms_iter.name;
536         }
537 }
538 #endif  /* CONFIG_KGDB_KDB */
539
540 static const struct file_operations kallsyms_operations = {
541         .open = kallsyms_open,
542         .read = seq_read,
543         .llseek = seq_lseek,
544         .release = seq_release_private,
545 };
546
547 static int __init kallsyms_init(void)
548 {
549         proc_create("kallsyms", 0444, NULL, &kallsyms_operations);
550         return 0;
551 }
552 device_initcall(kallsyms_init);