1 | /* |
2 | * Kernel Debugger Architecture Independent Support Functions |
3 | * |
4 | * This file is subject to the terms and conditions of the GNU General Public |
5 | * License. See the file "COPYING" in the main directory of this archive |
6 | * for more details. |
7 | * |
8 | * Copyright (c) 1999-2004 Silicon Graphics, Inc. All Rights Reserved. |
9 | * Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved. |
10 | * 03/02/13 added new 2.5 kallsyms <xavier.bru@bull.net> |
11 | */ |
12 | |
13 | #include <linux/types.h> |
14 | #include <linux/sched.h> |
15 | #include <linux/mm.h> |
16 | #include <linux/kallsyms.h> |
17 | #include <linux/stddef.h> |
18 | #include <linux/vmalloc.h> |
19 | #include <linux/ptrace.h> |
20 | #include <linux/highmem.h> |
21 | #include <linux/hardirq.h> |
22 | #include <linux/delay.h> |
23 | #include <linux/uaccess.h> |
24 | #include <linux/kdb.h> |
25 | #include <linux/slab.h> |
26 | #include <linux/ctype.h> |
27 | #include "kdb_private.h" |
28 | |
29 | /* |
30 | * kdbgetsymval - Return the address of the given symbol. |
31 | * |
32 | * Parameters: |
33 | * symname Character string containing symbol name |
34 | * symtab Structure to receive results |
35 | * Returns: |
36 | * 0 Symbol not found, symtab zero filled |
37 | * 1 Symbol mapped to module/symbol/section, data in symtab |
38 | */ |
39 | int kdbgetsymval(const char *symname, kdb_symtab_t *symtab) |
40 | { |
41 | kdb_dbg_printf(AR, "symname=%s, symtab=%px\n" , symname, symtab); |
42 | memset(symtab, 0, sizeof(*symtab)); |
43 | symtab->sym_start = kallsyms_lookup_name(name: symname); |
44 | if (symtab->sym_start) { |
45 | kdb_dbg_printf(AR, "returns 1, symtab->sym_start=0x%lx\n" , |
46 | symtab->sym_start); |
47 | return 1; |
48 | } |
49 | kdb_dbg_printf(AR, "returns 0\n" ); |
50 | return 0; |
51 | } |
52 | EXPORT_SYMBOL(kdbgetsymval); |
53 | |
54 | /** |
55 | * kdbnearsym() - Return the name of the symbol with the nearest address |
56 | * less than @addr. |
57 | * @addr: Address to check for near symbol |
58 | * @symtab: Structure to receive results |
59 | * |
60 | * WARNING: This function may return a pointer to a single statically |
61 | * allocated buffer (namebuf). kdb's unusual calling context (single |
62 | * threaded, all other CPUs halted) provides us sufficient locking for |
63 | * this to be safe. The only constraint imposed by the static buffer is |
64 | * that the caller must consume any previous reply prior to another call |
65 | * to lookup a new symbol. |
66 | * |
67 | * Note that, strictly speaking, some architectures may re-enter the kdb |
68 | * trap if the system turns out to be very badly damaged and this breaks |
69 | * the single-threaded assumption above. In these circumstances successful |
70 | * continuation and exit from the inner trap is unlikely to work and any |
71 | * user attempting this receives a prominent warning before being allowed |
72 | * to progress. In these circumstances we remain memory safe because |
73 | * namebuf[KSYM_NAME_LEN-1] will never change from '\0' although we do |
74 | * tolerate the possibility of garbled symbol display from the outer kdb |
75 | * trap. |
76 | * |
77 | * Return: |
78 | * * 0 - No sections contain this address, symtab zero filled |
79 | * * 1 - Address mapped to module/symbol/section, data in symtab |
80 | */ |
81 | int kdbnearsym(unsigned long addr, kdb_symtab_t *symtab) |
82 | { |
83 | int ret = 0; |
84 | unsigned long symbolsize = 0; |
85 | unsigned long offset = 0; |
86 | static char namebuf[KSYM_NAME_LEN]; |
87 | |
88 | kdb_dbg_printf(AR, "addr=0x%lx, symtab=%px\n" , addr, symtab); |
89 | memset(symtab, 0, sizeof(*symtab)); |
90 | |
91 | if (addr < 4096) |
92 | goto out; |
93 | |
94 | symtab->sym_name = kallsyms_lookup(addr, symbolsize: &symbolsize , offset: &offset, |
95 | modname: (char **)(&symtab->mod_name), namebuf); |
96 | if (offset > 8*1024*1024) { |
97 | symtab->sym_name = NULL; |
98 | addr = offset = symbolsize = 0; |
99 | } |
100 | symtab->sym_start = addr - offset; |
101 | symtab->sym_end = symtab->sym_start + symbolsize; |
102 | ret = symtab->sym_name != NULL && *(symtab->sym_name) != '\0'; |
103 | |
104 | if (symtab->mod_name == NULL) |
105 | symtab->mod_name = "kernel" ; |
106 | kdb_dbg_printf(AR, "returns %d symtab->sym_start=0x%lx, symtab->mod_name=%px, symtab->sym_name=%px (%s)\n" , |
107 | ret, symtab->sym_start, symtab->mod_name, symtab->sym_name, symtab->sym_name); |
108 | out: |
109 | return ret; |
110 | } |
111 | |
112 | static char ks_namebuf[KSYM_NAME_LEN+1], ks_namebuf_prev[KSYM_NAME_LEN+1]; |
113 | |
114 | /* |
115 | * kallsyms_symbol_complete |
116 | * |
117 | * Parameters: |
118 | * prefix_name prefix of a symbol name to lookup |
119 | * max_len maximum length that can be returned |
120 | * Returns: |
121 | * Number of symbols which match the given prefix. |
122 | * Notes: |
123 | * prefix_name is changed to contain the longest unique prefix that |
124 | * starts with this prefix (tab completion). |
125 | */ |
126 | int kallsyms_symbol_complete(char *prefix_name, int max_len) |
127 | { |
128 | loff_t pos = 0; |
129 | int prefix_len = strlen(prefix_name), prev_len = 0; |
130 | int i, number = 0; |
131 | const char *name; |
132 | |
133 | while ((name = kdb_walk_kallsyms(pos: &pos))) { |
134 | if (strncmp(name, prefix_name, prefix_len) == 0) { |
135 | strscpy(ks_namebuf, name, sizeof(ks_namebuf)); |
136 | /* Work out the longest name that matches the prefix */ |
137 | if (++number == 1) { |
138 | prev_len = min_t(int, max_len-1, |
139 | strlen(ks_namebuf)); |
140 | memcpy(ks_namebuf_prev, ks_namebuf, prev_len); |
141 | ks_namebuf_prev[prev_len] = '\0'; |
142 | continue; |
143 | } |
144 | for (i = 0; i < prev_len; i++) { |
145 | if (ks_namebuf[i] != ks_namebuf_prev[i]) { |
146 | prev_len = i; |
147 | ks_namebuf_prev[i] = '\0'; |
148 | break; |
149 | } |
150 | } |
151 | } |
152 | } |
153 | if (prev_len > prefix_len) |
154 | memcpy(prefix_name, ks_namebuf_prev, prev_len+1); |
155 | return number; |
156 | } |
157 | |
158 | /* |
159 | * kallsyms_symbol_next |
160 | * |
161 | * Parameters: |
162 | * prefix_name prefix of a symbol name to lookup |
163 | * flag 0 means search from the head, 1 means continue search. |
164 | * buf_size maximum length that can be written to prefix_name |
165 | * buffer |
166 | * Returns: |
167 | * 1 if a symbol matches the given prefix. |
168 | * 0 if no string found |
169 | */ |
170 | int kallsyms_symbol_next(char *prefix_name, int flag, int buf_size) |
171 | { |
172 | int prefix_len = strlen(prefix_name); |
173 | static loff_t pos; |
174 | const char *name; |
175 | |
176 | if (!flag) |
177 | pos = 0; |
178 | |
179 | while ((name = kdb_walk_kallsyms(pos: &pos))) { |
180 | if (!strncmp(name, prefix_name, prefix_len)) |
181 | return strscpy(prefix_name, name, buf_size); |
182 | } |
183 | return 0; |
184 | } |
185 | |
186 | /* |
187 | * kdb_symbol_print - Standard method for printing a symbol name and offset. |
188 | * Inputs: |
189 | * addr Address to be printed. |
190 | * symtab Address of symbol data, if NULL this routine does its |
191 | * own lookup. |
192 | * punc Punctuation for string, bit field. |
193 | * Remarks: |
194 | * The string and its punctuation is only printed if the address |
195 | * is inside the kernel, except that the value is always printed |
196 | * when requested. |
197 | */ |
198 | void kdb_symbol_print(unsigned long addr, const kdb_symtab_t *symtab_p, |
199 | unsigned int punc) |
200 | { |
201 | kdb_symtab_t symtab, *symtab_p2; |
202 | if (symtab_p) { |
203 | symtab_p2 = (kdb_symtab_t *)symtab_p; |
204 | } else { |
205 | symtab_p2 = &symtab; |
206 | kdbnearsym(addr, symtab: symtab_p2); |
207 | } |
208 | if (!(symtab_p2->sym_name || (punc & KDB_SP_VALUE))) |
209 | return; |
210 | if (punc & KDB_SP_SPACEB) |
211 | kdb_printf(" " ); |
212 | if (punc & KDB_SP_VALUE) |
213 | kdb_printf(kdb_machreg_fmt0, addr); |
214 | if (symtab_p2->sym_name) { |
215 | if (punc & KDB_SP_VALUE) |
216 | kdb_printf(" " ); |
217 | if (punc & KDB_SP_PAREN) |
218 | kdb_printf("(" ); |
219 | if (strcmp(symtab_p2->mod_name, "kernel" )) |
220 | kdb_printf("[%s]" , symtab_p2->mod_name); |
221 | kdb_printf("%s" , symtab_p2->sym_name); |
222 | if (addr != symtab_p2->sym_start) |
223 | kdb_printf("+0x%lx" , addr - symtab_p2->sym_start); |
224 | if (punc & KDB_SP_SYMSIZE) |
225 | kdb_printf("/0x%lx" , |
226 | symtab_p2->sym_end - symtab_p2->sym_start); |
227 | if (punc & KDB_SP_PAREN) |
228 | kdb_printf(")" ); |
229 | } |
230 | if (punc & KDB_SP_SPACEA) |
231 | kdb_printf(" " ); |
232 | if (punc & KDB_SP_NEWLINE) |
233 | kdb_printf("\n" ); |
234 | } |
235 | |
236 | /* |
237 | * kdb_strdup - kdb equivalent of strdup, for disasm code. |
238 | * Inputs: |
239 | * str The string to duplicate. |
240 | * type Flags to kmalloc for the new string. |
241 | * Returns: |
242 | * Address of the new string, NULL if storage could not be allocated. |
243 | * Remarks: |
244 | * This is not in lib/string.c because it uses kmalloc which is not |
245 | * available when string.o is used in boot loaders. |
246 | */ |
247 | char *kdb_strdup(const char *str, gfp_t type) |
248 | { |
249 | int n = strlen(str)+1; |
250 | char *s = kmalloc(size: n, flags: type); |
251 | if (!s) |
252 | return NULL; |
253 | return strcpy(p: s, q: str); |
254 | } |
255 | |
256 | /* |
257 | * kdb_getarea_size - Read an area of data. The kdb equivalent of |
258 | * copy_from_user, with kdb messages for invalid addresses. |
259 | * Inputs: |
260 | * res Pointer to the area to receive the result. |
261 | * addr Address of the area to copy. |
262 | * size Size of the area. |
263 | * Returns: |
264 | * 0 for success, < 0 for error. |
265 | */ |
266 | int kdb_getarea_size(void *res, unsigned long addr, size_t size) |
267 | { |
268 | int ret = copy_from_kernel_nofault(dst: (char *)res, src: (char *)addr, size); |
269 | if (ret) { |
270 | if (!KDB_STATE(SUPPRESS)) { |
271 | kdb_func_printf("Bad address 0x%lx\n" , addr); |
272 | KDB_STATE_SET(SUPPRESS); |
273 | } |
274 | ret = KDB_BADADDR; |
275 | } else { |
276 | KDB_STATE_CLEAR(SUPPRESS); |
277 | } |
278 | return ret; |
279 | } |
280 | |
281 | /* |
282 | * kdb_putarea_size - Write an area of data. The kdb equivalent of |
283 | * copy_to_user, with kdb messages for invalid addresses. |
284 | * Inputs: |
285 | * addr Address of the area to write to. |
286 | * res Pointer to the area holding the data. |
287 | * size Size of the area. |
288 | * Returns: |
289 | * 0 for success, < 0 for error. |
290 | */ |
291 | int kdb_putarea_size(unsigned long addr, void *res, size_t size) |
292 | { |
293 | int ret = copy_to_kernel_nofault(dst: (char *)addr, src: (char *)res, size); |
294 | if (ret) { |
295 | if (!KDB_STATE(SUPPRESS)) { |
296 | kdb_func_printf("Bad address 0x%lx\n" , addr); |
297 | KDB_STATE_SET(SUPPRESS); |
298 | } |
299 | ret = KDB_BADADDR; |
300 | } else { |
301 | KDB_STATE_CLEAR(SUPPRESS); |
302 | } |
303 | return ret; |
304 | } |
305 | |
306 | /* |
307 | * kdb_getphys - Read data from a physical address. Validate the |
308 | * address is in range, use kmap_atomic() to get data |
309 | * similar to kdb_getarea() - but for phys addresses |
310 | * Inputs: |
311 | * res Pointer to the word to receive the result |
312 | * addr Physical address of the area to copy |
313 | * size Size of the area |
314 | * Returns: |
315 | * 0 for success, < 0 for error. |
316 | */ |
317 | static int kdb_getphys(void *res, unsigned long addr, size_t size) |
318 | { |
319 | unsigned long pfn; |
320 | void *vaddr; |
321 | struct page *page; |
322 | |
323 | pfn = (addr >> PAGE_SHIFT); |
324 | if (!pfn_valid(pfn)) |
325 | return 1; |
326 | page = pfn_to_page(pfn); |
327 | vaddr = kmap_atomic(page); |
328 | memcpy(res, vaddr + (addr & (PAGE_SIZE - 1)), size); |
329 | kunmap_atomic(vaddr); |
330 | |
331 | return 0; |
332 | } |
333 | |
334 | /* |
335 | * kdb_getphysword |
336 | * Inputs: |
337 | * word Pointer to the word to receive the result. |
338 | * addr Address of the area to copy. |
339 | * size Size of the area. |
340 | * Returns: |
341 | * 0 for success, < 0 for error. |
342 | */ |
343 | int kdb_getphysword(unsigned long *word, unsigned long addr, size_t size) |
344 | { |
345 | int diag; |
346 | __u8 w1; |
347 | __u16 w2; |
348 | __u32 w4; |
349 | __u64 w8; |
350 | *word = 0; /* Default value if addr or size is invalid */ |
351 | |
352 | switch (size) { |
353 | case 1: |
354 | diag = kdb_getphys(res: &w1, addr, size: sizeof(w1)); |
355 | if (!diag) |
356 | *word = w1; |
357 | break; |
358 | case 2: |
359 | diag = kdb_getphys(res: &w2, addr, size: sizeof(w2)); |
360 | if (!diag) |
361 | *word = w2; |
362 | break; |
363 | case 4: |
364 | diag = kdb_getphys(res: &w4, addr, size: sizeof(w4)); |
365 | if (!diag) |
366 | *word = w4; |
367 | break; |
368 | case 8: |
369 | if (size <= sizeof(*word)) { |
370 | diag = kdb_getphys(res: &w8, addr, size: sizeof(w8)); |
371 | if (!diag) |
372 | *word = w8; |
373 | break; |
374 | } |
375 | fallthrough; |
376 | default: |
377 | diag = KDB_BADWIDTH; |
378 | kdb_func_printf("bad width %zu\n" , size); |
379 | } |
380 | return diag; |
381 | } |
382 | |
383 | /* |
384 | * kdb_getword - Read a binary value. Unlike kdb_getarea, this treats |
385 | * data as numbers. |
386 | * Inputs: |
387 | * word Pointer to the word to receive the result. |
388 | * addr Address of the area to copy. |
389 | * size Size of the area. |
390 | * Returns: |
391 | * 0 for success, < 0 for error. |
392 | */ |
393 | int kdb_getword(unsigned long *word, unsigned long addr, size_t size) |
394 | { |
395 | int diag; |
396 | __u8 w1; |
397 | __u16 w2; |
398 | __u32 w4; |
399 | __u64 w8; |
400 | *word = 0; /* Default value if addr or size is invalid */ |
401 | switch (size) { |
402 | case 1: |
403 | diag = kdb_getarea(w1, addr); |
404 | if (!diag) |
405 | *word = w1; |
406 | break; |
407 | case 2: |
408 | diag = kdb_getarea(w2, addr); |
409 | if (!diag) |
410 | *word = w2; |
411 | break; |
412 | case 4: |
413 | diag = kdb_getarea(w4, addr); |
414 | if (!diag) |
415 | *word = w4; |
416 | break; |
417 | case 8: |
418 | if (size <= sizeof(*word)) { |
419 | diag = kdb_getarea(w8, addr); |
420 | if (!diag) |
421 | *word = w8; |
422 | break; |
423 | } |
424 | fallthrough; |
425 | default: |
426 | diag = KDB_BADWIDTH; |
427 | kdb_func_printf("bad width %zu\n" , size); |
428 | } |
429 | return diag; |
430 | } |
431 | |
432 | /* |
433 | * kdb_putword - Write a binary value. Unlike kdb_putarea, this |
434 | * treats data as numbers. |
435 | * Inputs: |
436 | * addr Address of the area to write to.. |
437 | * word The value to set. |
438 | * size Size of the area. |
439 | * Returns: |
440 | * 0 for success, < 0 for error. |
441 | */ |
442 | int kdb_putword(unsigned long addr, unsigned long word, size_t size) |
443 | { |
444 | int diag; |
445 | __u8 w1; |
446 | __u16 w2; |
447 | __u32 w4; |
448 | __u64 w8; |
449 | switch (size) { |
450 | case 1: |
451 | w1 = word; |
452 | diag = kdb_putarea(addr, w1); |
453 | break; |
454 | case 2: |
455 | w2 = word; |
456 | diag = kdb_putarea(addr, w2); |
457 | break; |
458 | case 4: |
459 | w4 = word; |
460 | diag = kdb_putarea(addr, w4); |
461 | break; |
462 | case 8: |
463 | if (size <= sizeof(word)) { |
464 | w8 = word; |
465 | diag = kdb_putarea(addr, w8); |
466 | break; |
467 | } |
468 | fallthrough; |
469 | default: |
470 | diag = KDB_BADWIDTH; |
471 | kdb_func_printf("bad width %zu\n" , size); |
472 | } |
473 | return diag; |
474 | } |
475 | |
476 | |
477 | |
478 | /* |
479 | * kdb_task_state_char - Return the character that represents the task state. |
480 | * Inputs: |
481 | * p struct task for the process |
482 | * Returns: |
483 | * One character to represent the task state. |
484 | */ |
485 | char kdb_task_state_char (const struct task_struct *p) |
486 | { |
487 | unsigned long tmp; |
488 | char state; |
489 | int cpu; |
490 | |
491 | if (!p || |
492 | copy_from_kernel_nofault(dst: &tmp, src: (char *)p, size: sizeof(unsigned long))) |
493 | return 'E'; |
494 | |
495 | state = task_state_to_char(tsk: (struct task_struct *) p); |
496 | |
497 | if (is_idle_task(p)) { |
498 | /* Idle task. Is it really idle, apart from the kdb |
499 | * interrupt? */ |
500 | cpu = kdb_process_cpu(p); |
501 | if (!kdb_task_has_cpu(p) || kgdb_info[cpu].irq_depth == 1) { |
502 | if (cpu != kdb_initial_cpu) |
503 | state = '-'; /* idle task */ |
504 | } |
505 | } else if (!p->mm && strchr("IMS" , state)) { |
506 | state = tolower(state); /* sleeping system daemon */ |
507 | } |
508 | return state; |
509 | } |
510 | |
511 | /* |
512 | * kdb_task_state - Return true if a process has the desired state |
513 | * given by the mask. |
514 | * Inputs: |
515 | * p struct task for the process |
516 | * mask set of characters used to select processes; both NULL |
517 | * and the empty string mean adopt a default filter, which |
518 | * is to suppress sleeping system daemons and the idle tasks |
519 | * Returns: |
520 | * True if the process matches at least one criteria defined by the mask. |
521 | */ |
522 | bool kdb_task_state(const struct task_struct *p, const char *mask) |
523 | { |
524 | char state = kdb_task_state_char(p); |
525 | |
526 | /* If there is no mask, then we will filter code that runs when the |
527 | * scheduler is idling and any system daemons that are currently |
528 | * sleeping. |
529 | */ |
530 | if (!mask || mask[0] == '\0') |
531 | return !strchr("-ims" , state); |
532 | |
533 | /* A is a special case that matches all states */ |
534 | if (strchr(mask, 'A')) |
535 | return true; |
536 | |
537 | return strchr(mask, state); |
538 | } |
539 | |
540 | /* Maintain a small stack of kdb_flags to allow recursion without disturbing |
541 | * the global kdb state. |
542 | */ |
543 | |
544 | static int kdb_flags_stack[4], kdb_flags_index; |
545 | |
546 | void kdb_save_flags(void) |
547 | { |
548 | BUG_ON(kdb_flags_index >= ARRAY_SIZE(kdb_flags_stack)); |
549 | kdb_flags_stack[kdb_flags_index++] = kdb_flags; |
550 | } |
551 | |
552 | void kdb_restore_flags(void) |
553 | { |
554 | BUG_ON(kdb_flags_index <= 0); |
555 | kdb_flags = kdb_flags_stack[--kdb_flags_index]; |
556 | } |
557 | |