kthread: rename probe_kthread_data() to kthread_probe_data()
[linux-2.6-block.git] / kernel / kallsyms.c
CommitLineData
1da177e4
LT
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>
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 */
1da177e4 23#include <linux/mm.h>
07354a00 24#include <linux/ctype.h>
5a0e3ad6 25#include <linux/slab.h>
52f5684c 26#include <linux/compiler.h>
1da177e4
LT
27
28#include <asm/sections.h>
29
30#ifdef CONFIG_KALLSYMS_ALL
31#define all_var 1
32#else
33#define all_var 0
34#endif
35
ad6ccfad
MK
36/*
37 * These will be re-linked against their real values
38 * during the second link stage.
39 */
52f5684c 40extern const unsigned long kallsyms_addresses[] __weak;
2213e9a6 41extern const int kallsyms_offsets[] __weak;
52f5684c 42extern const u8 kallsyms_names[] __weak;
1da177e4 43
ad6ccfad
MK
44/*
45 * Tell the compiler that the count isn't in the small data section if the arch
46 * has one (eg: FRV).
9e6c1e63
DH
47 */
48extern const unsigned long kallsyms_num_syms
2ea03891 49__attribute__((weak, section(".rodata")));
9e6c1e63 50
2213e9a6
AB
51extern const unsigned long kallsyms_relative_base
52__attribute__((weak, section(".rodata")));
53
52f5684c
GID
54extern const u8 kallsyms_token_table[] __weak;
55extern const u16 kallsyms_token_index[] __weak;
1da177e4 56
52f5684c 57extern const unsigned long kallsyms_markers[] __weak;
1da177e4
LT
58
59static inline int is_kernel_inittext(unsigned long addr)
60{
61 if (addr >= (unsigned long)_sinittext
62 && addr <= (unsigned long)_einittext)
63 return 1;
64 return 0;
65}
66
67static inline int is_kernel_text(unsigned long addr)
68{
128e8db3
MF
69 if ((addr >= (unsigned long)_stext && addr <= (unsigned long)_etext) ||
70 arch_is_kernel_text(addr))
1da177e4 71 return 1;
cae5d390 72 return in_gate_area_no_mm(addr);
1da177e4
LT
73}
74
75static inline int is_kernel(unsigned long addr)
76{
77 if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
78 return 1;
cae5d390 79 return in_gate_area_no_mm(addr);
1da177e4
LT
80}
81
ffc50891
FBH
82static int is_ksym_addr(unsigned long addr)
83{
84 if (all_var)
85 return is_kernel(addr);
86
a3b81113 87 return is_kernel_text(addr) || is_kernel_inittext(addr);
ffc50891
FBH
88}
89
ad6ccfad
MK
90/*
91 * Expand a compressed symbol data into the resulting uncompressed string,
e3f26752 92 * if uncompressed string is too long (>= maxlen), it will be truncated,
ad6ccfad
MK
93 * given the offset to where the symbol is in the compressed stream.
94 */
e3f26752
CG
95static unsigned int kallsyms_expand_symbol(unsigned int off,
96 char *result, size_t maxlen)
1da177e4
LT
97{
98 int len, skipped_first = 0;
aad09470 99 const u8 *tptr, *data;
1da177e4 100
ad6ccfad 101 /* Get the compressed symbol length from the first symbol byte. */
1da177e4
LT
102 data = &kallsyms_names[off];
103 len = *data;
104 data++;
105
ad6ccfad
MK
106 /*
107 * Update the offset to return the offset for the next symbol on
108 * the compressed stream.
109 */
1da177e4
LT
110 off += len + 1;
111
ad6ccfad
MK
112 /*
113 * For every byte on the compressed symbol data, copy the table
114 * entry for that byte.
115 */
116 while (len) {
117 tptr = &kallsyms_token_table[kallsyms_token_index[*data]];
1da177e4
LT
118 data++;
119 len--;
120
121 while (*tptr) {
ad6ccfad 122 if (skipped_first) {
e3f26752
CG
123 if (maxlen <= 1)
124 goto tail;
1da177e4
LT
125 *result = *tptr;
126 result++;
e3f26752 127 maxlen--;
1da177e4
LT
128 } else
129 skipped_first = 1;
130 tptr++;
131 }
132 }
133
e3f26752
CG
134tail:
135 if (maxlen)
136 *result = '\0';
1da177e4 137
ad6ccfad 138 /* Return to offset to the next symbol. */
1da177e4
LT
139 return off;
140}
141
ad6ccfad
MK
142/*
143 * Get symbol type information. This is encoded as a single char at the
144 * beginning of the symbol name.
145 */
1da177e4
LT
146static char kallsyms_get_symbol_type(unsigned int off)
147{
ad6ccfad
MK
148 /*
149 * Get just the first code, look it up in the token table,
150 * and return the first char from this token.
151 */
152 return kallsyms_token_table[kallsyms_token_index[kallsyms_names[off + 1]]];
1da177e4
LT
153}
154
155
ad6ccfad
MK
156/*
157 * Find the offset on the compressed stream given and index in the
158 * kallsyms array.
159 */
1da177e4
LT
160static unsigned int get_symbol_offset(unsigned long pos)
161{
aad09470 162 const u8 *name;
1da177e4
LT
163 int i;
164
ad6ccfad
MK
165 /*
166 * Use the closest marker we have. We have markers every 256 positions,
167 * so that should be close enough.
168 */
169 name = &kallsyms_names[kallsyms_markers[pos >> 8]];
1da177e4 170
ad6ccfad
MK
171 /*
172 * Sequentially scan all the symbols up to the point we're searching
173 * for. Every symbol is stored in a [<len>][<len> bytes of data] format,
174 * so we just need to add the len to the current pointer for every
175 * symbol we wish to skip.
176 */
177 for (i = 0; i < (pos & 0xFF); i++)
1da177e4
LT
178 name = name + (*name) + 1;
179
180 return name - kallsyms_names;
181}
182
2213e9a6
AB
183static unsigned long kallsyms_sym_address(int idx)
184{
185 if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE))
186 return kallsyms_addresses[idx];
187
188 /* values are unsigned offsets if --absolute-percpu is not in effect */
189 if (!IS_ENABLED(CONFIG_KALLSYMS_ABSOLUTE_PERCPU))
190 return kallsyms_relative_base + (u32)kallsyms_offsets[idx];
191
192 /* ...otherwise, positive offsets are absolute values */
193 if (kallsyms_offsets[idx] >= 0)
194 return kallsyms_offsets[idx];
195
196 /* ...and negative offsets are relative to kallsyms_relative_base - 1 */
197 return kallsyms_relative_base - 1 - kallsyms_offsets[idx];
198}
199
1da177e4
LT
200/* Lookup the address for this symbol. Returns 0 if not found. */
201unsigned long kallsyms_lookup_name(const char *name)
202{
9281acea 203 char namebuf[KSYM_NAME_LEN];
1da177e4
LT
204 unsigned long i;
205 unsigned int off;
206
207 for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
e3f26752 208 off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
1da177e4
LT
209
210 if (strcmp(namebuf, name) == 0)
2213e9a6 211 return kallsyms_sym_address(i);
1da177e4
LT
212 }
213 return module_kallsyms_lookup_name(name);
214}
f60d24d2 215EXPORT_SYMBOL_GPL(kallsyms_lookup_name);
1da177e4 216
75a66614
AK
217int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
218 unsigned long),
219 void *data)
220{
221 char namebuf[KSYM_NAME_LEN];
222 unsigned long i;
223 unsigned int off;
224 int ret;
225
226 for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
e3f26752 227 off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
2213e9a6 228 ret = fn(data, namebuf, NULL, kallsyms_sym_address(i));
75a66614
AK
229 if (ret != 0)
230 return ret;
231 }
232 return module_kallsyms_on_each_symbol(fn, data);
233}
234EXPORT_SYMBOL_GPL(kallsyms_on_each_symbol);
235
ffc50891
FBH
236static unsigned long get_symbol_pos(unsigned long addr,
237 unsigned long *symbolsize,
238 unsigned long *offset)
239{
240 unsigned long symbol_start = 0, symbol_end = 0;
241 unsigned long i, low, high, mid;
242
2ea03891 243 /* This kernel should never had been booted. */
2213e9a6
AB
244 if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE))
245 BUG_ON(!kallsyms_addresses);
246 else
247 BUG_ON(!kallsyms_offsets);
2ea03891 248
ad6ccfad 249 /* Do a binary search on the sorted kallsyms_addresses array. */
ffc50891
FBH
250 low = 0;
251 high = kallsyms_num_syms;
252
253 while (high - low > 1) {
2fc9c4e1 254 mid = low + (high - low) / 2;
2213e9a6 255 if (kallsyms_sym_address(mid) <= addr)
ffc50891
FBH
256 low = mid;
257 else
258 high = mid;
259 }
260
261 /*
ad6ccfad
MK
262 * Search for the first aliased symbol. Aliased
263 * symbols are symbols with the same address.
ffc50891 264 */
2213e9a6 265 while (low && kallsyms_sym_address(low-1) == kallsyms_sym_address(low))
ffc50891
FBH
266 --low;
267
2213e9a6 268 symbol_start = kallsyms_sym_address(low);
ffc50891 269
ad6ccfad 270 /* Search for next non-aliased symbol. */
ffc50891 271 for (i = low + 1; i < kallsyms_num_syms; i++) {
2213e9a6
AB
272 if (kallsyms_sym_address(i) > symbol_start) {
273 symbol_end = kallsyms_sym_address(i);
ffc50891
FBH
274 break;
275 }
276 }
277
ad6ccfad 278 /* If we found no next symbol, we use the end of the section. */
ffc50891
FBH
279 if (!symbol_end) {
280 if (is_kernel_inittext(addr))
281 symbol_end = (unsigned long)_einittext;
282 else if (all_var)
283 symbol_end = (unsigned long)_end;
284 else
285 symbol_end = (unsigned long)_etext;
286 }
287
ffb45122
AD
288 if (symbolsize)
289 *symbolsize = symbol_end - symbol_start;
290 if (offset)
291 *offset = addr - symbol_start;
ffc50891
FBH
292
293 return low;
294}
295
296/*
297 * Lookup an address but don't bother to find any names.
298 */
299int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize,
300 unsigned long *offset)
301{
6dd06c9f 302 char namebuf[KSYM_NAME_LEN];
ffc50891
FBH
303 if (is_ksym_addr(addr))
304 return !!get_symbol_pos(addr, symbolsize, offset);
305
6dd06c9f 306 return !!module_address_lookup(addr, symbolsize, offset, NULL, namebuf);
ffc50891
FBH
307}
308
1da177e4
LT
309/*
310 * Lookup an address
ad6ccfad
MK
311 * - modname is set to NULL if it's in the kernel.
312 * - We guarantee that the returned name is valid until we reschedule even if.
313 * It resides in a module.
314 * - We also guarantee that modname will be valid until rescheduled.
1da177e4
LT
315 */
316const char *kallsyms_lookup(unsigned long addr,
317 unsigned long *symbolsize,
318 unsigned long *offset,
319 char **modname, char *namebuf)
320{
9281acea 321 namebuf[KSYM_NAME_LEN - 1] = 0;
1da177e4
LT
322 namebuf[0] = 0;
323
ffc50891
FBH
324 if (is_ksym_addr(addr)) {
325 unsigned long pos;
1da177e4 326
ffc50891 327 pos = get_symbol_pos(addr, symbolsize, offset);
1da177e4 328 /* Grab name */
e3f26752
CG
329 kallsyms_expand_symbol(get_symbol_offset(pos),
330 namebuf, KSYM_NAME_LEN);
7a74fc49
KM
331 if (modname)
332 *modname = NULL;
1da177e4
LT
333 return namebuf;
334 }
335
ad6ccfad 336 /* See if it's in a module. */
6dd06c9f
RR
337 return module_address_lookup(addr, symbolsize, offset, modname,
338 namebuf);
1da177e4
LT
339}
340
9d65cb4a
AD
341int lookup_symbol_name(unsigned long addr, char *symname)
342{
343 symname[0] = '\0';
9281acea 344 symname[KSYM_NAME_LEN - 1] = '\0';
9d65cb4a
AD
345
346 if (is_ksym_addr(addr)) {
347 unsigned long pos;
348
349 pos = get_symbol_pos(addr, NULL, NULL);
350 /* Grab name */
e3f26752
CG
351 kallsyms_expand_symbol(get_symbol_offset(pos),
352 symname, KSYM_NAME_LEN);
9d65cb4a
AD
353 return 0;
354 }
ad6ccfad 355 /* See if it's in a module. */
9d65cb4a
AD
356 return lookup_module_symbol_name(addr, symname);
357}
358
a5c43dae
AD
359int lookup_symbol_attrs(unsigned long addr, unsigned long *size,
360 unsigned long *offset, char *modname, char *name)
361{
362 name[0] = '\0';
9281acea 363 name[KSYM_NAME_LEN - 1] = '\0';
a5c43dae
AD
364
365 if (is_ksym_addr(addr)) {
366 unsigned long pos;
367
368 pos = get_symbol_pos(addr, size, offset);
369 /* Grab name */
e3f26752
CG
370 kallsyms_expand_symbol(get_symbol_offset(pos),
371 name, KSYM_NAME_LEN);
a5c43dae
AD
372 modname[0] = '\0';
373 return 0;
374 }
ad6ccfad 375 /* See if it's in a module. */
a5c43dae
AD
376 return lookup_module_symbol_attrs(addr, size, offset, modname, name);
377}
378
42e38083 379/* Look up a kernel symbol and return it in a text buffer. */
0f77a8d3 380static int __sprint_symbol(char *buffer, unsigned long address,
4796dd20 381 int symbol_offset, int add_offset)
1da177e4
LT
382{
383 char *modname;
384 const char *name;
385 unsigned long offset, size;
966c8c12 386 int len;
1da177e4 387
0f77a8d3 388 address += symbol_offset;
966c8c12 389 name = kallsyms_lookup(address, &size, &offset, &modname, buffer);
1da177e4 390 if (!name)
b86280aa 391 return sprintf(buffer, "0x%lx", address - symbol_offset);
19769b76 392
966c8c12
HD
393 if (name != buffer)
394 strcpy(buffer, name);
395 len = strlen(buffer);
0f77a8d3 396 offset -= symbol_offset;
966c8c12 397
4796dd20
SB
398 if (add_offset)
399 len += sprintf(buffer + len, "+%#lx/%#lx", offset, size);
400
19769b76 401 if (modname)
4796dd20 402 len += sprintf(buffer + len, " [%s]", modname);
966c8c12
HD
403
404 return len;
42e38083 405}
0f77a8d3
NK
406
407/**
408 * sprint_symbol - Look up a kernel symbol and return it in a text buffer
409 * @buffer: buffer to be stored
410 * @address: address to lookup
411 *
412 * This function looks up a kernel symbol with @address and stores its name,
413 * offset, size and module name to @buffer if possible. If no symbol was found,
414 * just saves its @address as is.
415 *
416 * This function returns the number of bytes stored in @buffer.
417 */
418int sprint_symbol(char *buffer, unsigned long address)
419{
4796dd20 420 return __sprint_symbol(buffer, address, 0, 1);
0f77a8d3 421}
ad6ccfad 422EXPORT_SYMBOL_GPL(sprint_symbol);
42e38083 423
4796dd20
SB
424/**
425 * sprint_symbol_no_offset - Look up a kernel symbol and return it in a text buffer
426 * @buffer: buffer to be stored
427 * @address: address to lookup
428 *
429 * This function looks up a kernel symbol with @address and stores its name
430 * and module name to @buffer if possible. If no symbol was found, just saves
431 * its @address as is.
432 *
433 * This function returns the number of bytes stored in @buffer.
434 */
435int sprint_symbol_no_offset(char *buffer, unsigned long address)
436{
437 return __sprint_symbol(buffer, address, 0, 0);
438}
439EXPORT_SYMBOL_GPL(sprint_symbol_no_offset);
440
0f77a8d3
NK
441/**
442 * sprint_backtrace - Look up a backtrace symbol and return it in a text buffer
443 * @buffer: buffer to be stored
444 * @address: address to lookup
445 *
446 * This function is for stack backtrace and does the same thing as
447 * sprint_symbol() but with modified/decreased @address. If there is a
448 * tail-call to the function marked "noreturn", gcc optimized out code after
449 * the call so that the stack-saved return address could point outside of the
450 * caller. This function ensures that kallsyms will find the original caller
451 * by decreasing @address.
452 *
453 * This function returns the number of bytes stored in @buffer.
454 */
455int sprint_backtrace(char *buffer, unsigned long address)
456{
4796dd20 457 return __sprint_symbol(buffer, address, -1, 1);
0f77a8d3
NK
458}
459
42e38083
RP
460/* Look up a kernel symbol and print it to the kernel messages. */
461void __print_symbol(const char *fmt, unsigned long address)
462{
463 char buffer[KSYM_SYMBOL_LEN];
464
465 sprint_symbol(buffer, address);
466
1da177e4
LT
467 printk(fmt, buffer);
468}
ad6ccfad 469EXPORT_SYMBOL(__print_symbol);
1da177e4
LT
470
471/* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
ad6ccfad 472struct kallsym_iter {
1da177e4 473 loff_t pos;
1da177e4 474 unsigned long value;
ad6ccfad 475 unsigned int nameoff; /* If iterating in core kernel symbols. */
1da177e4 476 char type;
9281acea
TH
477 char name[KSYM_NAME_LEN];
478 char module_name[MODULE_NAME_LEN];
ea07890a 479 int exported;
1da177e4
LT
480};
481
1da177e4
LT
482static int get_ksymbol_mod(struct kallsym_iter *iter)
483{
ea07890a
AD
484 if (module_get_kallsym(iter->pos - kallsyms_num_syms, &iter->value,
485 &iter->type, iter->name, iter->module_name,
486 &iter->exported) < 0)
1da177e4 487 return 0;
1da177e4
LT
488 return 1;
489}
490
491/* Returns space to next name. */
492static unsigned long get_ksymbol_core(struct kallsym_iter *iter)
493{
494 unsigned off = iter->nameoff;
495
ea07890a 496 iter->module_name[0] = '\0';
2213e9a6 497 iter->value = kallsyms_sym_address(iter->pos);
1da177e4
LT
498
499 iter->type = kallsyms_get_symbol_type(off);
500
e3f26752 501 off = kallsyms_expand_symbol(off, iter->name, ARRAY_SIZE(iter->name));
1da177e4
LT
502
503 return off - iter->nameoff;
504}
505
506static void reset_iter(struct kallsym_iter *iter, loff_t new_pos)
507{
508 iter->name[0] = '\0';
509 iter->nameoff = get_symbol_offset(new_pos);
510 iter->pos = new_pos;
511}
512
513/* Returns false if pos at or past end of file. */
514static int update_iter(struct kallsym_iter *iter, loff_t pos)
515{
516 /* Module symbols can be accessed randomly. */
517 if (pos >= kallsyms_num_syms) {
518 iter->pos = pos;
519 return get_ksymbol_mod(iter);
520 }
ad6ccfad 521
1da177e4
LT
522 /* If we're not on the desired position, reset to new position. */
523 if (pos != iter->pos)
524 reset_iter(iter, pos);
525
526 iter->nameoff += get_ksymbol_core(iter);
527 iter->pos++;
528
529 return 1;
530}
531
532static void *s_next(struct seq_file *m, void *p, loff_t *pos)
533{
534 (*pos)++;
535
536 if (!update_iter(m->private, *pos))
537 return NULL;
538 return p;
539}
540
541static void *s_start(struct seq_file *m, loff_t *pos)
542{
543 if (!update_iter(m->private, *pos))
544 return NULL;
545 return m->private;
546}
547
548static void s_stop(struct seq_file *m, void *p)
549{
550}
551
552static int s_show(struct seq_file *m, void *p)
553{
554 struct kallsym_iter *iter = m->private;
555
ad6ccfad 556 /* Some debugging symbols have no name. Ignore them. */
1da177e4
LT
557 if (!iter->name[0])
558 return 0;
559
ea07890a
AD
560 if (iter->module_name[0]) {
561 char type;
562
ad6ccfad
MK
563 /*
564 * Label it "global" if it is exported,
565 * "local" if not exported.
566 */
ea07890a
AD
567 type = iter->exported ? toupper(iter->type) :
568 tolower(iter->type);
9f36e2c4
KC
569 seq_printf(m, "%pK %c %s\t[%s]\n", (void *)iter->value,
570 type, iter->name, iter->module_name);
ea07890a 571 } else
9f36e2c4
KC
572 seq_printf(m, "%pK %c %s\n", (void *)iter->value,
573 iter->type, iter->name);
1da177e4
LT
574 return 0;
575}
576
15ad7cdc 577static const struct seq_operations kallsyms_op = {
1da177e4
LT
578 .start = s_start,
579 .next = s_next,
580 .stop = s_stop,
581 .show = s_show
582};
583
584static int kallsyms_open(struct inode *inode, struct file *file)
585{
ad6ccfad
MK
586 /*
587 * We keep iterator in m->private, since normal case is to
1da177e4 588 * s_start from where we left off, so we avoid doing
ad6ccfad
MK
589 * using get_symbol_offset for every symbol.
590 */
1da177e4 591 struct kallsym_iter *iter;
0049f26a 592 iter = __seq_open_private(file, &kallsyms_op, sizeof(*iter));
1da177e4
LT
593 if (!iter)
594 return -ENOMEM;
595 reset_iter(iter, 0);
596
0049f26a 597 return 0;
1da177e4
LT
598}
599
67fc4e0c
JW
600#ifdef CONFIG_KGDB_KDB
601const char *kdb_walk_kallsyms(loff_t *pos)
602{
603 static struct kallsym_iter kdb_walk_kallsyms_iter;
604 if (*pos == 0) {
605 memset(&kdb_walk_kallsyms_iter, 0,
606 sizeof(kdb_walk_kallsyms_iter));
607 reset_iter(&kdb_walk_kallsyms_iter, 0);
608 }
609 while (1) {
610 if (!update_iter(&kdb_walk_kallsyms_iter, *pos))
611 return NULL;
612 ++*pos;
613 /* Some debugging symbols have no name. Ignore them. */
614 if (kdb_walk_kallsyms_iter.name[0])
615 return kdb_walk_kallsyms_iter.name;
616 }
617}
618#endif /* CONFIG_KGDB_KDB */
619
15ad7cdc 620static const struct file_operations kallsyms_operations = {
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621 .open = kallsyms_open,
622 .read = seq_read,
623 .llseek = seq_lseek,
5a0c6a0d 624 .release = seq_release_private,
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625};
626
627static int __init kallsyms_init(void)
628{
33e0d57f 629 proc_create("kallsyms", 0444, NULL, &kallsyms_operations);
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630 return 0;
631}
ad6ccfad 632device_initcall(kallsyms_init);