ia64/linux-2.6.18-xen.hg

view kernel/kallsyms.c @ 562:66faefe721eb

pvSCSI backend driver

Signed-off-by: Tomonari Horikoshi <t.horikoshi@jp.fujitsu.com>
Signed-off-by: Jun Kamada <kama@jp.fujitsu.com>
author Keir Fraser <keir.fraser@citrix.com>
date Mon Jun 02 09:58:27 2008 +0100 (2008-06-02)
parents 831230e53067
children
line source
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/sched.h> /* for cond_resched */
22 #include <linux/mm.h>
24 #include <asm/sections.h>
26 #ifdef CONFIG_KALLSYMS_ALL
27 #define all_var 1
28 #else
29 #define all_var 0
30 #endif
32 /* These will be re-linked against their real values during the second link stage */
33 extern unsigned long kallsyms_addresses[] __attribute__((weak));
34 extern unsigned long kallsyms_num_syms __attribute__((weak,section("data")));
35 extern u8 kallsyms_names[] __attribute__((weak));
37 extern u8 kallsyms_token_table[] __attribute__((weak));
38 extern u16 kallsyms_token_index[] __attribute__((weak));
40 extern unsigned long kallsyms_markers[] __attribute__((weak));
42 static inline int is_kernel_inittext(unsigned long addr)
43 {
44 if (addr >= (unsigned long)_sinittext
45 && addr <= (unsigned long)_einittext)
46 return 1;
47 return 0;
48 }
50 static inline int is_kernel_extratext(unsigned long addr)
51 {
52 if (addr >= (unsigned long)_sextratext
53 && addr <= (unsigned long)_eextratext)
54 return 1;
55 return 0;
56 }
58 static inline int is_kernel_text(unsigned long addr)
59 {
60 if (addr >= (unsigned long)_stext && addr <= (unsigned long)_etext)
61 return 1;
62 return in_gate_area_no_task(addr);
63 }
65 static inline int is_kernel(unsigned long addr)
66 {
67 if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
68 return 1;
69 return in_gate_area_no_task(addr);
70 }
72 /* expand a compressed symbol data into the resulting uncompressed string,
73 given the offset to where the symbol is in the compressed stream */
74 static unsigned int kallsyms_expand_symbol(unsigned int off, char *result)
75 {
76 int len, skipped_first = 0;
77 u8 *tptr, *data;
79 /* get the compressed symbol length from the first symbol byte */
80 data = &kallsyms_names[off];
81 len = *data;
82 data++;
84 /* update the offset to return the offset for the next symbol on
85 * the compressed stream */
86 off += len + 1;
88 /* for every byte on the compressed symbol data, copy the table
89 entry for that byte */
90 while(len) {
91 tptr = &kallsyms_token_table[ kallsyms_token_index[*data] ];
92 data++;
93 len--;
95 while (*tptr) {
96 if(skipped_first) {
97 *result = *tptr;
98 result++;
99 } else
100 skipped_first = 1;
101 tptr++;
102 }
103 }
105 *result = '\0';
107 /* return to offset to the next symbol */
108 return off;
109 }
111 /* get symbol type information. This is encoded as a single char at the
112 * begining of the symbol name */
113 static char kallsyms_get_symbol_type(unsigned int off)
114 {
115 /* get just the first code, look it up in the token table, and return the
116 * first char from this token */
117 return kallsyms_token_table[ kallsyms_token_index[ kallsyms_names[off+1] ] ];
118 }
121 /* find the offset on the compressed stream given and index in the
122 * kallsyms array */
123 static unsigned int get_symbol_offset(unsigned long pos)
124 {
125 u8 *name;
126 int i;
128 /* use the closest marker we have. We have markers every 256 positions,
129 * so that should be close enough */
130 name = &kallsyms_names[ kallsyms_markers[pos>>8] ];
132 /* sequentially scan all the symbols up to the point we're searching for.
133 * Every symbol is stored in a [<len>][<len> bytes of data] format, so we
134 * just need to add the len to the current pointer for every symbol we
135 * wish to skip */
136 for(i = 0; i < (pos&0xFF); i++)
137 name = name + (*name) + 1;
139 return name - kallsyms_names;
140 }
142 /* Lookup the address for this symbol. Returns 0 if not found. */
143 unsigned long kallsyms_lookup_name(const char *name)
144 {
145 char namebuf[KSYM_NAME_LEN+1];
146 unsigned long i;
147 unsigned int off;
149 for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
150 off = kallsyms_expand_symbol(off, namebuf);
152 if (strcmp(namebuf, name) == 0)
153 return kallsyms_addresses[i];
154 }
155 return module_kallsyms_lookup_name(name);
156 }
157 EXPORT_SYMBOL_GPL(kallsyms_lookup_name);
159 /*
160 * Lookup an address
161 * - modname is set to NULL if it's in the kernel
162 * - we guarantee that the returned name is valid until we reschedule even if
163 * it resides in a module
164 * - we also guarantee that modname will be valid until rescheduled
165 */
166 const char *kallsyms_lookup(unsigned long addr,
167 unsigned long *symbolsize,
168 unsigned long *offset,
169 char **modname, char *namebuf)
170 {
171 unsigned long i, low, high, mid;
172 const char *msym;
174 /* This kernel should never had been booted. */
175 BUG_ON(!kallsyms_addresses);
177 namebuf[KSYM_NAME_LEN] = 0;
178 namebuf[0] = 0;
180 if ((all_var && is_kernel(addr)) ||
181 (!all_var && (is_kernel_text(addr) || is_kernel_inittext(addr) ||
182 is_kernel_extratext(addr)))) {
183 unsigned long symbol_end = 0;
185 /* do a binary search on the sorted kallsyms_addresses array */
186 low = 0;
187 high = kallsyms_num_syms;
189 while (high-low > 1) {
190 mid = (low + high) / 2;
191 if (kallsyms_addresses[mid] <= addr) low = mid;
192 else high = mid;
193 }
195 /* search for the first aliased symbol. Aliased symbols are
196 symbols with the same address */
197 while (low && kallsyms_addresses[low - 1] == kallsyms_addresses[low])
198 --low;
200 /* Grab name */
201 kallsyms_expand_symbol(get_symbol_offset(low), namebuf);
203 /* Search for next non-aliased symbol */
204 for (i = low + 1; i < kallsyms_num_syms; i++) {
205 if (kallsyms_addresses[i] > kallsyms_addresses[low]) {
206 symbol_end = kallsyms_addresses[i];
207 break;
208 }
209 }
211 /* if we found no next symbol, we use the end of the section */
212 if (!symbol_end) {
213 if (is_kernel_inittext(addr))
214 symbol_end = (unsigned long)_einittext;
215 else
216 symbol_end = all_var ? (unsigned long)_end : (unsigned long)_etext;
217 }
219 *symbolsize = symbol_end - kallsyms_addresses[low];
220 *modname = NULL;
221 *offset = addr - kallsyms_addresses[low];
222 return namebuf;
223 }
225 /* see if it's in a module */
226 msym = module_address_lookup(addr, symbolsize, offset, modname);
227 if (msym)
228 return strncpy(namebuf, msym, KSYM_NAME_LEN);
230 return NULL;
231 }
233 /* Replace "%s" in format with address, or returns -errno. */
234 void __print_symbol(const char *fmt, unsigned long address)
235 {
236 char *modname;
237 const char *name;
238 unsigned long offset, size;
239 char namebuf[KSYM_NAME_LEN+1];
240 char buffer[sizeof("%s+%#lx/%#lx [%s]") + KSYM_NAME_LEN +
241 2*(BITS_PER_LONG*3/10) + MODULE_NAME_LEN + 1];
243 name = kallsyms_lookup(address, &size, &offset, &modname, namebuf);
245 if (!name)
246 sprintf(buffer, "0x%lx", address);
247 else {
248 if (modname)
249 sprintf(buffer, "%s+%#lx/%#lx [%s]", name, offset,
250 size, modname);
251 else
252 sprintf(buffer, "%s+%#lx/%#lx", name, offset, size);
253 }
254 printk(fmt, buffer);
255 }
257 /* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
258 struct kallsym_iter
259 {
260 loff_t pos;
261 struct module *owner;
262 unsigned long value;
263 unsigned int nameoff; /* If iterating in core kernel symbols */
264 char type;
265 char name[KSYM_NAME_LEN+1];
266 };
268 /* Only label it "global" if it is exported. */
269 static void upcase_if_global(struct kallsym_iter *iter)
270 {
271 if (is_exported(iter->name, iter->owner))
272 iter->type += 'A' - 'a';
273 }
275 static int get_ksymbol_mod(struct kallsym_iter *iter)
276 {
277 iter->owner = module_get_kallsym(iter->pos - kallsyms_num_syms,
278 &iter->value, &iter->type,
279 iter->name, sizeof(iter->name));
280 if (iter->owner == NULL)
281 return 0;
283 upcase_if_global(iter);
284 return 1;
285 }
287 /* Returns space to next name. */
288 static unsigned long get_ksymbol_core(struct kallsym_iter *iter)
289 {
290 unsigned off = iter->nameoff;
292 iter->owner = NULL;
293 iter->value = kallsyms_addresses[iter->pos];
295 iter->type = kallsyms_get_symbol_type(off);
297 off = kallsyms_expand_symbol(off, iter->name);
299 return off - iter->nameoff;
300 }
302 static void reset_iter(struct kallsym_iter *iter, loff_t new_pos)
303 {
304 iter->name[0] = '\0';
305 iter->nameoff = get_symbol_offset(new_pos);
306 iter->pos = new_pos;
307 }
309 /* Returns false if pos at or past end of file. */
310 static int update_iter(struct kallsym_iter *iter, loff_t pos)
311 {
312 /* Module symbols can be accessed randomly. */
313 if (pos >= kallsyms_num_syms) {
314 iter->pos = pos;
315 return get_ksymbol_mod(iter);
316 }
318 /* If we're not on the desired position, reset to new position. */
319 if (pos != iter->pos)
320 reset_iter(iter, pos);
322 iter->nameoff += get_ksymbol_core(iter);
323 iter->pos++;
325 return 1;
326 }
328 static void *s_next(struct seq_file *m, void *p, loff_t *pos)
329 {
330 (*pos)++;
332 if (!update_iter(m->private, *pos))
333 return NULL;
334 return p;
335 }
337 static void *s_start(struct seq_file *m, loff_t *pos)
338 {
339 if (!update_iter(m->private, *pos))
340 return NULL;
341 return m->private;
342 }
344 static void s_stop(struct seq_file *m, void *p)
345 {
346 }
348 static int s_show(struct seq_file *m, void *p)
349 {
350 struct kallsym_iter *iter = m->private;
352 /* Some debugging symbols have no name. Ignore them. */
353 if (!iter->name[0])
354 return 0;
356 if (iter->owner)
357 seq_printf(m, "%0*lx %c %s\t[%s]\n",
358 (int)(2*sizeof(void*)),
359 iter->value, iter->type, iter->name,
360 module_name(iter->owner));
361 else
362 seq_printf(m, "%0*lx %c %s\n",
363 (int)(2*sizeof(void*)),
364 iter->value, iter->type, iter->name);
365 return 0;
366 }
368 static struct seq_operations kallsyms_op = {
369 .start = s_start,
370 .next = s_next,
371 .stop = s_stop,
372 .show = s_show
373 };
375 static int kallsyms_open(struct inode *inode, struct file *file)
376 {
377 /* We keep iterator in m->private, since normal case is to
378 * s_start from where we left off, so we avoid doing
379 * using get_symbol_offset for every symbol */
380 struct kallsym_iter *iter;
381 int ret;
383 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
384 if (!iter)
385 return -ENOMEM;
386 reset_iter(iter, 0);
388 ret = seq_open(file, &kallsyms_op);
389 if (ret == 0)
390 ((struct seq_file *)file->private_data)->private = iter;
391 else
392 kfree(iter);
393 return ret;
394 }
396 static int kallsyms_release(struct inode *inode, struct file *file)
397 {
398 struct seq_file *m = (struct seq_file *)file->private_data;
399 kfree(m->private);
400 return seq_release(inode, file);
401 }
403 static struct file_operations kallsyms_operations = {
404 .open = kallsyms_open,
405 .read = seq_read,
406 .llseek = seq_lseek,
407 .release = kallsyms_release,
408 };
410 static int __init kallsyms_init(void)
411 {
412 struct proc_dir_entry *entry;
414 entry = create_proc_entry("kallsyms", 0444, NULL);
415 if (entry)
416 entry->proc_fops = &kallsyms_operations;
417 return 0;
418 }
419 __initcall(kallsyms_init);
421 EXPORT_SYMBOL(__print_symbol);