Commit | Line | Data |
---|---|---|
4552d5dc JB |
1 | /* |
2 | * Copyright (C) 2002-2006 Novell, Inc. | |
3 | * Jan Beulich <jbeulich@novell.com> | |
4 | * This code is released under version 2 of the GNU GPL. | |
5 | * | |
6 | * A simple API for unwinding kernel stacks. This is used for | |
7 | * debugging and error reporting purposes. The kernel doesn't need | |
8 | * full-blown stack unwinding with all the bells and whistles, so there | |
9 | * is not much point in implementing the full Dwarf2 unwind API. | |
10 | */ | |
11 | ||
12 | #include <linux/unwind.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/delay.h> | |
15 | #include <linux/stop_machine.h> | |
16 | #include <asm/sections.h> | |
17 | #include <asm/uaccess.h> | |
18 | #include <asm/unaligned.h> | |
19 | ||
20 | extern char __start_unwind[], __end_unwind[]; | |
21 | ||
22 | #define MAX_STACK_DEPTH 8 | |
23 | ||
24 | #define EXTRA_INFO(f) { \ | |
25 | BUILD_BUG_ON_ZERO(offsetof(struct unwind_frame_info, f) \ | |
26 | % FIELD_SIZEOF(struct unwind_frame_info, f)) \ | |
27 | + offsetof(struct unwind_frame_info, f) \ | |
28 | / FIELD_SIZEOF(struct unwind_frame_info, f), \ | |
29 | FIELD_SIZEOF(struct unwind_frame_info, f) \ | |
30 | } | |
31 | #define PTREGS_INFO(f) EXTRA_INFO(regs.f) | |
32 | ||
33 | static const struct { | |
34 | unsigned offs:BITS_PER_LONG / 2; | |
35 | unsigned width:BITS_PER_LONG / 2; | |
36 | } reg_info[] = { | |
37 | UNW_REGISTER_INFO | |
38 | }; | |
39 | ||
40 | #undef PTREGS_INFO | |
41 | #undef EXTRA_INFO | |
42 | ||
43 | #ifndef REG_INVALID | |
44 | #define REG_INVALID(r) (reg_info[r].width == 0) | |
45 | #endif | |
46 | ||
47 | #define DW_CFA_nop 0x00 | |
48 | #define DW_CFA_set_loc 0x01 | |
49 | #define DW_CFA_advance_loc1 0x02 | |
50 | #define DW_CFA_advance_loc2 0x03 | |
51 | #define DW_CFA_advance_loc4 0x04 | |
52 | #define DW_CFA_offset_extended 0x05 | |
53 | #define DW_CFA_restore_extended 0x06 | |
54 | #define DW_CFA_undefined 0x07 | |
55 | #define DW_CFA_same_value 0x08 | |
56 | #define DW_CFA_register 0x09 | |
57 | #define DW_CFA_remember_state 0x0a | |
58 | #define DW_CFA_restore_state 0x0b | |
59 | #define DW_CFA_def_cfa 0x0c | |
60 | #define DW_CFA_def_cfa_register 0x0d | |
61 | #define DW_CFA_def_cfa_offset 0x0e | |
62 | #define DW_CFA_def_cfa_expression 0x0f | |
63 | #define DW_CFA_expression 0x10 | |
64 | #define DW_CFA_offset_extended_sf 0x11 | |
65 | #define DW_CFA_def_cfa_sf 0x12 | |
66 | #define DW_CFA_def_cfa_offset_sf 0x13 | |
67 | #define DW_CFA_val_offset 0x14 | |
68 | #define DW_CFA_val_offset_sf 0x15 | |
69 | #define DW_CFA_val_expression 0x16 | |
70 | #define DW_CFA_lo_user 0x1c | |
71 | #define DW_CFA_GNU_window_save 0x2d | |
72 | #define DW_CFA_GNU_args_size 0x2e | |
73 | #define DW_CFA_GNU_negative_offset_extended 0x2f | |
74 | #define DW_CFA_hi_user 0x3f | |
75 | ||
76 | #define DW_EH_PE_FORM 0x07 | |
77 | #define DW_EH_PE_native 0x00 | |
78 | #define DW_EH_PE_leb128 0x01 | |
79 | #define DW_EH_PE_data2 0x02 | |
80 | #define DW_EH_PE_data4 0x03 | |
81 | #define DW_EH_PE_data8 0x04 | |
82 | #define DW_EH_PE_signed 0x08 | |
83 | #define DW_EH_PE_ADJUST 0x70 | |
84 | #define DW_EH_PE_abs 0x00 | |
85 | #define DW_EH_PE_pcrel 0x10 | |
86 | #define DW_EH_PE_textrel 0x20 | |
87 | #define DW_EH_PE_datarel 0x30 | |
88 | #define DW_EH_PE_funcrel 0x40 | |
89 | #define DW_EH_PE_aligned 0x50 | |
90 | #define DW_EH_PE_indirect 0x80 | |
91 | #define DW_EH_PE_omit 0xff | |
92 | ||
93 | typedef unsigned long uleb128_t; | |
94 | typedef signed long sleb128_t; | |
95 | ||
96 | static struct unwind_table { | |
97 | struct { | |
98 | unsigned long pc; | |
99 | unsigned long range; | |
100 | } core, init; | |
101 | const void *address; | |
102 | unsigned long size; | |
103 | struct unwind_table *link; | |
104 | const char *name; | |
105 | } root_table, *last_table; | |
106 | ||
107 | struct unwind_item { | |
108 | enum item_location { | |
109 | Nowhere, | |
110 | Memory, | |
111 | Register, | |
112 | Value | |
113 | } where; | |
114 | uleb128_t value; | |
115 | }; | |
116 | ||
117 | struct unwind_state { | |
118 | uleb128_t loc, org; | |
119 | const u8 *cieStart, *cieEnd; | |
120 | uleb128_t codeAlign; | |
121 | sleb128_t dataAlign; | |
122 | struct cfa { | |
123 | uleb128_t reg, offs; | |
124 | } cfa; | |
125 | struct unwind_item regs[ARRAY_SIZE(reg_info)]; | |
126 | unsigned stackDepth:8; | |
127 | unsigned version:8; | |
128 | const u8 *label; | |
129 | const u8 *stack[MAX_STACK_DEPTH]; | |
130 | }; | |
131 | ||
132 | static const struct cfa badCFA = { ARRAY_SIZE(reg_info), 1 }; | |
133 | ||
134 | static struct unwind_table *find_table(unsigned long pc) | |
135 | { | |
136 | struct unwind_table *table; | |
137 | ||
138 | for (table = &root_table; table; table = table->link) | |
139 | if ((pc >= table->core.pc | |
140 | && pc < table->core.pc + table->core.range) | |
141 | || (pc >= table->init.pc | |
142 | && pc < table->init.pc + table->init.range)) | |
143 | break; | |
144 | ||
145 | return table; | |
146 | } | |
147 | ||
148 | static void init_unwind_table(struct unwind_table *table, | |
149 | const char *name, | |
150 | const void *core_start, | |
151 | unsigned long core_size, | |
152 | const void *init_start, | |
153 | unsigned long init_size, | |
154 | const void *table_start, | |
155 | unsigned long table_size) | |
156 | { | |
157 | table->core.pc = (unsigned long)core_start; | |
158 | table->core.range = core_size; | |
159 | table->init.pc = (unsigned long)init_start; | |
160 | table->init.range = init_size; | |
161 | table->address = table_start; | |
162 | table->size = table_size; | |
163 | table->link = NULL; | |
164 | table->name = name; | |
165 | } | |
166 | ||
167 | void __init unwind_init(void) | |
168 | { | |
169 | init_unwind_table(&root_table, "kernel", | |
170 | _text, _end - _text, | |
171 | NULL, 0, | |
172 | __start_unwind, __end_unwind - __start_unwind); | |
173 | } | |
174 | ||
83f4fcce JB |
175 | #ifdef CONFIG_MODULES |
176 | ||
4552d5dc JB |
177 | /* Must be called with module_mutex held. */ |
178 | void *unwind_add_table(struct module *module, | |
179 | const void *table_start, | |
180 | unsigned long table_size) | |
181 | { | |
182 | struct unwind_table *table; | |
183 | ||
184 | if (table_size <= 0) | |
185 | return NULL; | |
186 | ||
187 | table = kmalloc(sizeof(*table), GFP_KERNEL); | |
188 | if (!table) | |
189 | return NULL; | |
190 | ||
191 | init_unwind_table(table, module->name, | |
192 | module->module_core, module->core_size, | |
193 | module->module_init, module->init_size, | |
194 | table_start, table_size); | |
195 | ||
196 | if (last_table) | |
197 | last_table->link = table; | |
198 | else | |
199 | root_table.link = table; | |
200 | last_table = table; | |
201 | ||
202 | return table; | |
203 | } | |
204 | ||
205 | struct unlink_table_info | |
206 | { | |
207 | struct unwind_table *table; | |
208 | int init_only; | |
209 | }; | |
210 | ||
211 | static int unlink_table(void *arg) | |
212 | { | |
213 | struct unlink_table_info *info = arg; | |
214 | struct unwind_table *table = info->table, *prev; | |
215 | ||
216 | for (prev = &root_table; prev->link && prev->link != table; prev = prev->link) | |
217 | ; | |
218 | ||
219 | if (prev->link) { | |
220 | if (info->init_only) { | |
221 | table->init.pc = 0; | |
222 | table->init.range = 0; | |
223 | info->table = NULL; | |
224 | } else { | |
225 | prev->link = table->link; | |
226 | if (!prev->link) | |
227 | last_table = prev; | |
228 | } | |
229 | } else | |
230 | info->table = NULL; | |
231 | ||
232 | return 0; | |
233 | } | |
234 | ||
235 | /* Must be called with module_mutex held. */ | |
236 | void unwind_remove_table(void *handle, int init_only) | |
237 | { | |
238 | struct unwind_table *table = handle; | |
239 | struct unlink_table_info info; | |
240 | ||
241 | if (!table || table == &root_table) | |
242 | return; | |
243 | ||
244 | if (init_only && table == last_table) { | |
245 | table->init.pc = 0; | |
246 | table->init.range = 0; | |
247 | return; | |
248 | } | |
249 | ||
250 | info.table = table; | |
251 | info.init_only = init_only; | |
252 | stop_machine_run(unlink_table, &info, NR_CPUS); | |
253 | ||
254 | if (info.table) | |
255 | kfree(table); | |
256 | } | |
257 | ||
83f4fcce JB |
258 | #endif /* CONFIG_MODULES */ |
259 | ||
4552d5dc JB |
260 | static uleb128_t get_uleb128(const u8 **pcur, const u8 *end) |
261 | { | |
262 | const u8 *cur = *pcur; | |
263 | uleb128_t value; | |
264 | unsigned shift; | |
265 | ||
266 | for (shift = 0, value = 0; cur < end; shift += 7) { | |
267 | if (shift + 7 > 8 * sizeof(value) | |
268 | && (*cur & 0x7fU) >= (1U << (8 * sizeof(value) - shift))) { | |
269 | cur = end + 1; | |
270 | break; | |
271 | } | |
272 | value |= (uleb128_t)(*cur & 0x7f) << shift; | |
273 | if (!(*cur++ & 0x80)) | |
274 | break; | |
275 | } | |
276 | *pcur = cur; | |
277 | ||
278 | return value; | |
279 | } | |
280 | ||
281 | static sleb128_t get_sleb128(const u8 **pcur, const u8 *end) | |
282 | { | |
283 | const u8 *cur = *pcur; | |
284 | sleb128_t value; | |
285 | unsigned shift; | |
286 | ||
287 | for (shift = 0, value = 0; cur < end; shift += 7) { | |
288 | if (shift + 7 > 8 * sizeof(value) | |
289 | && (*cur & 0x7fU) >= (1U << (8 * sizeof(value) - shift))) { | |
290 | cur = end + 1; | |
291 | break; | |
292 | } | |
293 | value |= (sleb128_t)(*cur & 0x7f) << shift; | |
294 | if (!(*cur & 0x80)) { | |
295 | value |= -(*cur++ & 0x40) << shift; | |
296 | break; | |
297 | } | |
298 | } | |
299 | *pcur = cur; | |
300 | ||
301 | return value; | |
302 | } | |
303 | ||
304 | static unsigned long read_pointer(const u8 **pLoc, | |
305 | const void *end, | |
306 | signed ptrType) | |
307 | { | |
308 | unsigned long value = 0; | |
309 | union { | |
310 | const u8 *p8; | |
311 | const u16 *p16u; | |
312 | const s16 *p16s; | |
313 | const u32 *p32u; | |
314 | const s32 *p32s; | |
315 | const unsigned long *pul; | |
316 | } ptr; | |
317 | ||
318 | if (ptrType < 0 || ptrType == DW_EH_PE_omit) | |
319 | return 0; | |
320 | ptr.p8 = *pLoc; | |
321 | switch(ptrType & DW_EH_PE_FORM) { | |
322 | case DW_EH_PE_data2: | |
323 | if (end < (const void *)(ptr.p16u + 1)) | |
324 | return 0; | |
325 | if(ptrType & DW_EH_PE_signed) | |
326 | value = get_unaligned(ptr.p16s++); | |
327 | else | |
328 | value = get_unaligned(ptr.p16u++); | |
329 | break; | |
330 | case DW_EH_PE_data4: | |
331 | #ifdef CONFIG_64BIT | |
332 | if (end < (const void *)(ptr.p32u + 1)) | |
333 | return 0; | |
334 | if(ptrType & DW_EH_PE_signed) | |
335 | value = get_unaligned(ptr.p32s++); | |
336 | else | |
337 | value = get_unaligned(ptr.p32u++); | |
338 | break; | |
339 | case DW_EH_PE_data8: | |
340 | BUILD_BUG_ON(sizeof(u64) != sizeof(value)); | |
341 | #else | |
342 | BUILD_BUG_ON(sizeof(u32) != sizeof(value)); | |
343 | #endif | |
344 | case DW_EH_PE_native: | |
345 | if (end < (const void *)(ptr.pul + 1)) | |
346 | return 0; | |
347 | value = get_unaligned(ptr.pul++); | |
348 | break; | |
349 | case DW_EH_PE_leb128: | |
350 | BUILD_BUG_ON(sizeof(uleb128_t) > sizeof(value)); | |
351 | value = ptrType & DW_EH_PE_signed | |
352 | ? get_sleb128(&ptr.p8, end) | |
353 | : get_uleb128(&ptr.p8, end); | |
354 | if ((const void *)ptr.p8 > end) | |
355 | return 0; | |
356 | break; | |
357 | default: | |
358 | return 0; | |
359 | } | |
360 | switch(ptrType & DW_EH_PE_ADJUST) { | |
361 | case DW_EH_PE_abs: | |
362 | break; | |
363 | case DW_EH_PE_pcrel: | |
364 | value += (unsigned long)*pLoc; | |
365 | break; | |
366 | default: | |
367 | return 0; | |
368 | } | |
369 | if ((ptrType & DW_EH_PE_indirect) | |
370 | && __get_user(value, (unsigned long *)value)) | |
371 | return 0; | |
372 | *pLoc = ptr.p8; | |
373 | ||
374 | return value; | |
375 | } | |
376 | ||
377 | static signed fde_pointer_type(const u32 *cie) | |
378 | { | |
379 | const u8 *ptr = (const u8 *)(cie + 2); | |
380 | unsigned version = *ptr; | |
381 | ||
382 | if (version != 1) | |
383 | return -1; /* unsupported */ | |
384 | if (*++ptr) { | |
385 | const char *aug; | |
386 | const u8 *end = (const u8 *)(cie + 1) + *cie; | |
387 | uleb128_t len; | |
388 | ||
389 | /* check if augmentation size is first (and thus present) */ | |
390 | if (*ptr != 'z') | |
391 | return -1; | |
392 | /* check if augmentation string is nul-terminated */ | |
393 | if ((ptr = memchr(aug = (const void *)ptr, 0, end - ptr)) == NULL) | |
394 | return -1; | |
395 | ++ptr; /* skip terminator */ | |
396 | get_uleb128(&ptr, end); /* skip code alignment */ | |
397 | get_sleb128(&ptr, end); /* skip data alignment */ | |
398 | /* skip return address column */ | |
399 | version <= 1 ? (void)++ptr : (void)get_uleb128(&ptr, end); | |
400 | len = get_uleb128(&ptr, end); /* augmentation length */ | |
401 | if (ptr + len < ptr || ptr + len > end) | |
402 | return -1; | |
403 | end = ptr + len; | |
404 | while (*++aug) { | |
405 | if (ptr >= end) | |
406 | return -1; | |
407 | switch(*aug) { | |
408 | case 'L': | |
409 | ++ptr; | |
410 | break; | |
411 | case 'P': { | |
412 | signed ptrType = *ptr++; | |
413 | ||
414 | if (!read_pointer(&ptr, end, ptrType) || ptr > end) | |
415 | return -1; | |
416 | } | |
417 | break; | |
418 | case 'R': | |
419 | return *ptr; | |
420 | default: | |
421 | return -1; | |
422 | } | |
423 | } | |
424 | } | |
425 | return DW_EH_PE_native|DW_EH_PE_abs; | |
426 | } | |
427 | ||
428 | static int advance_loc(unsigned long delta, struct unwind_state *state) | |
429 | { | |
430 | state->loc += delta * state->codeAlign; | |
431 | ||
432 | return delta > 0; | |
433 | } | |
434 | ||
435 | static void set_rule(uleb128_t reg, | |
436 | enum item_location where, | |
437 | uleb128_t value, | |
438 | struct unwind_state *state) | |
439 | { | |
440 | if (reg < ARRAY_SIZE(state->regs)) { | |
441 | state->regs[reg].where = where; | |
442 | state->regs[reg].value = value; | |
443 | } | |
444 | } | |
445 | ||
446 | static int processCFI(const u8 *start, | |
447 | const u8 *end, | |
448 | unsigned long targetLoc, | |
449 | signed ptrType, | |
450 | struct unwind_state *state) | |
451 | { | |
452 | union { | |
453 | const u8 *p8; | |
454 | const u16 *p16; | |
455 | const u32 *p32; | |
456 | } ptr; | |
457 | int result = 1; | |
458 | ||
459 | if (start != state->cieStart) { | |
460 | state->loc = state->org; | |
461 | result = processCFI(state->cieStart, state->cieEnd, 0, ptrType, state); | |
462 | if (targetLoc == 0 && state->label == NULL) | |
463 | return result; | |
464 | } | |
465 | for (ptr.p8 = start; result && ptr.p8 < end; ) { | |
466 | switch(*ptr.p8 >> 6) { | |
467 | uleb128_t value; | |
468 | ||
469 | case 0: | |
470 | switch(*ptr.p8++) { | |
471 | case DW_CFA_nop: | |
472 | break; | |
473 | case DW_CFA_set_loc: | |
474 | if ((state->loc = read_pointer(&ptr.p8, end, ptrType)) == 0) | |
475 | result = 0; | |
476 | break; | |
477 | case DW_CFA_advance_loc1: | |
478 | result = ptr.p8 < end && advance_loc(*ptr.p8++, state); | |
479 | break; | |
480 | case DW_CFA_advance_loc2: | |
481 | result = ptr.p8 <= end + 2 | |
482 | && advance_loc(*ptr.p16++, state); | |
483 | break; | |
484 | case DW_CFA_advance_loc4: | |
485 | result = ptr.p8 <= end + 4 | |
486 | && advance_loc(*ptr.p32++, state); | |
487 | break; | |
488 | case DW_CFA_offset_extended: | |
489 | value = get_uleb128(&ptr.p8, end); | |
490 | set_rule(value, Memory, get_uleb128(&ptr.p8, end), state); | |
491 | break; | |
492 | case DW_CFA_val_offset: | |
493 | value = get_uleb128(&ptr.p8, end); | |
494 | set_rule(value, Value, get_uleb128(&ptr.p8, end), state); | |
495 | break; | |
496 | case DW_CFA_offset_extended_sf: | |
497 | value = get_uleb128(&ptr.p8, end); | |
498 | set_rule(value, Memory, get_sleb128(&ptr.p8, end), state); | |
499 | break; | |
500 | case DW_CFA_val_offset_sf: | |
501 | value = get_uleb128(&ptr.p8, end); | |
502 | set_rule(value, Value, get_sleb128(&ptr.p8, end), state); | |
503 | break; | |
504 | case DW_CFA_restore_extended: | |
505 | case DW_CFA_undefined: | |
506 | case DW_CFA_same_value: | |
507 | set_rule(get_uleb128(&ptr.p8, end), Nowhere, 0, state); | |
508 | break; | |
509 | case DW_CFA_register: | |
510 | value = get_uleb128(&ptr.p8, end); | |
511 | set_rule(value, | |
512 | Register, | |
513 | get_uleb128(&ptr.p8, end), state); | |
514 | break; | |
515 | case DW_CFA_remember_state: | |
516 | if (ptr.p8 == state->label) { | |
517 | state->label = NULL; | |
518 | return 1; | |
519 | } | |
520 | if (state->stackDepth >= MAX_STACK_DEPTH) | |
521 | return 0; | |
522 | state->stack[state->stackDepth++] = ptr.p8; | |
523 | break; | |
524 | case DW_CFA_restore_state: | |
525 | if (state->stackDepth) { | |
526 | const uleb128_t loc = state->loc; | |
527 | const u8 *label = state->label; | |
528 | ||
529 | state->label = state->stack[state->stackDepth - 1]; | |
530 | memcpy(&state->cfa, &badCFA, sizeof(state->cfa)); | |
531 | memset(state->regs, 0, sizeof(state->regs)); | |
532 | state->stackDepth = 0; | |
533 | result = processCFI(start, end, 0, ptrType, state); | |
534 | state->loc = loc; | |
535 | state->label = label; | |
536 | } else | |
537 | return 0; | |
538 | break; | |
539 | case DW_CFA_def_cfa: | |
540 | state->cfa.reg = get_uleb128(&ptr.p8, end); | |
541 | /*nobreak*/ | |
542 | case DW_CFA_def_cfa_offset: | |
543 | state->cfa.offs = get_uleb128(&ptr.p8, end); | |
544 | break; | |
545 | case DW_CFA_def_cfa_sf: | |
546 | state->cfa.reg = get_uleb128(&ptr.p8, end); | |
547 | /*nobreak*/ | |
548 | case DW_CFA_def_cfa_offset_sf: | |
549 | state->cfa.offs = get_sleb128(&ptr.p8, end) | |
550 | * state->dataAlign; | |
551 | break; | |
552 | case DW_CFA_def_cfa_register: | |
553 | state->cfa.reg = get_uleb128(&ptr.p8, end); | |
554 | break; | |
555 | /*todo case DW_CFA_def_cfa_expression: */ | |
556 | /*todo case DW_CFA_expression: */ | |
557 | /*todo case DW_CFA_val_expression: */ | |
558 | case DW_CFA_GNU_args_size: | |
559 | get_uleb128(&ptr.p8, end); | |
560 | break; | |
561 | case DW_CFA_GNU_negative_offset_extended: | |
562 | value = get_uleb128(&ptr.p8, end); | |
563 | set_rule(value, | |
564 | Memory, | |
565 | (uleb128_t)0 - get_uleb128(&ptr.p8, end), state); | |
566 | break; | |
567 | case DW_CFA_GNU_window_save: | |
568 | default: | |
569 | result = 0; | |
570 | break; | |
571 | } | |
572 | break; | |
573 | case 1: | |
574 | result = advance_loc(*ptr.p8++ & 0x3f, state); | |
575 | break; | |
576 | case 2: | |
577 | value = *ptr.p8++ & 0x3f; | |
578 | set_rule(value, Memory, get_uleb128(&ptr.p8, end), state); | |
579 | break; | |
580 | case 3: | |
581 | set_rule(*ptr.p8++ & 0x3f, Nowhere, 0, state); | |
582 | break; | |
583 | } | |
584 | if (ptr.p8 > end) | |
585 | result = 0; | |
586 | if (result && targetLoc != 0 && targetLoc < state->loc) | |
587 | return 1; | |
588 | } | |
589 | ||
590 | return result | |
591 | && ptr.p8 == end | |
592 | && (targetLoc == 0 | |
593 | || (/*todo While in theory this should apply, gcc in practice omits | |
594 | everything past the function prolog, and hence the location | |
595 | never reaches the end of the function. | |
596 | targetLoc < state->loc &&*/ state->label == NULL)); | |
597 | } | |
598 | ||
599 | /* Unwind to previous to frame. Returns 0 if successful, negative | |
600 | * number in case of an error. */ | |
601 | int unwind(struct unwind_frame_info *frame) | |
602 | { | |
603 | #define FRAME_REG(r, t) (((t *)frame)[reg_info[r].offs]) | |
604 | const u32 *fde = NULL, *cie = NULL; | |
605 | const u8 *ptr = NULL, *end = NULL; | |
606 | unsigned long startLoc = 0, endLoc = 0, cfa; | |
607 | unsigned i; | |
608 | signed ptrType = -1; | |
609 | uleb128_t retAddrReg = 0; | |
610 | struct unwind_table *table; | |
611 | struct unwind_state state; | |
612 | ||
613 | if (UNW_PC(frame) == 0) | |
614 | return -EINVAL; | |
615 | if ((table = find_table(UNW_PC(frame))) != NULL | |
616 | && !(table->size & (sizeof(*fde) - 1))) { | |
617 | unsigned long tableSize = table->size; | |
618 | ||
619 | for (fde = table->address; | |
620 | tableSize > sizeof(*fde) && tableSize - sizeof(*fde) >= *fde; | |
621 | tableSize -= sizeof(*fde) + *fde, | |
622 | fde += 1 + *fde / sizeof(*fde)) { | |
623 | if (!*fde || (*fde & (sizeof(*fde) - 1))) | |
624 | break; | |
625 | if (!fde[1]) | |
626 | continue; /* this is a CIE */ | |
627 | if ((fde[1] & (sizeof(*fde) - 1)) | |
628 | || fde[1] > (unsigned long)(fde + 1) | |
629 | - (unsigned long)table->address) | |
630 | continue; /* this is not a valid FDE */ | |
631 | cie = fde + 1 - fde[1] / sizeof(*fde); | |
632 | if (*cie <= sizeof(*cie) + 4 | |
633 | || *cie >= fde[1] - sizeof(*fde) | |
634 | || (*cie & (sizeof(*cie) - 1)) | |
635 | || cie[1] | |
636 | || (ptrType = fde_pointer_type(cie)) < 0) { | |
637 | cie = NULL; /* this is not a (valid) CIE */ | |
638 | continue; | |
639 | } | |
640 | ptr = (const u8 *)(fde + 2); | |
641 | startLoc = read_pointer(&ptr, | |
642 | (const u8 *)(fde + 1) + *fde, | |
643 | ptrType); | |
644 | endLoc = startLoc | |
645 | + read_pointer(&ptr, | |
646 | (const u8 *)(fde + 1) + *fde, | |
647 | ptrType & DW_EH_PE_indirect | |
648 | ? ptrType | |
649 | : ptrType & (DW_EH_PE_FORM|DW_EH_PE_signed)); | |
650 | if (UNW_PC(frame) >= startLoc && UNW_PC(frame) < endLoc) | |
651 | break; | |
652 | cie = NULL; | |
653 | } | |
654 | } | |
655 | if (cie != NULL) { | |
656 | memset(&state, 0, sizeof(state)); | |
657 | state.cieEnd = ptr; /* keep here temporarily */ | |
658 | ptr = (const u8 *)(cie + 2); | |
659 | end = (const u8 *)(cie + 1) + *cie; | |
660 | if ((state.version = *ptr) != 1) | |
661 | cie = NULL; /* unsupported version */ | |
662 | else if (*++ptr) { | |
663 | /* check if augmentation size is first (and thus present) */ | |
664 | if (*ptr == 'z') { | |
665 | /* check for ignorable (or already handled) | |
666 | * nul-terminated augmentation string */ | |
667 | while (++ptr < end && *ptr) | |
668 | if (strchr("LPR", *ptr) == NULL) | |
669 | break; | |
670 | } | |
671 | if (ptr >= end || *ptr) | |
672 | cie = NULL; | |
673 | } | |
674 | ++ptr; | |
675 | } | |
676 | if (cie != NULL) { | |
677 | /* get code aligment factor */ | |
678 | state.codeAlign = get_uleb128(&ptr, end); | |
679 | /* get data aligment factor */ | |
680 | state.dataAlign = get_sleb128(&ptr, end); | |
681 | if (state.codeAlign == 0 || state.dataAlign == 0 || ptr >= end) | |
682 | cie = NULL; | |
683 | else { | |
684 | retAddrReg = state.version <= 1 ? *ptr++ : get_uleb128(&ptr, end); | |
685 | /* skip augmentation */ | |
686 | if (((const char *)(cie + 2))[1] == 'z') | |
687 | ptr += get_uleb128(&ptr, end); | |
688 | if (ptr > end | |
689 | || retAddrReg >= ARRAY_SIZE(reg_info) | |
690 | || REG_INVALID(retAddrReg) | |
691 | || reg_info[retAddrReg].width != sizeof(unsigned long)) | |
692 | cie = NULL; | |
693 | } | |
694 | } | |
695 | if (cie != NULL) { | |
696 | state.cieStart = ptr; | |
697 | ptr = state.cieEnd; | |
698 | state.cieEnd = end; | |
699 | end = (const u8 *)(fde + 1) + *fde; | |
700 | /* skip augmentation */ | |
701 | if (((const char *)(cie + 2))[1] == 'z') { | |
702 | uleb128_t augSize = get_uleb128(&ptr, end); | |
703 | ||
704 | if ((ptr += augSize) > end) | |
705 | fde = NULL; | |
706 | } | |
707 | } | |
708 | if (cie == NULL || fde == NULL) { | |
709 | #ifdef CONFIG_FRAME_POINTER | |
710 | unsigned long top, bottom; | |
711 | #endif | |
712 | ||
713 | #ifdef CONFIG_FRAME_POINTER | |
714 | top = STACK_TOP(frame->task); | |
715 | bottom = STACK_BOTTOM(frame->task); | |
716 | # if FRAME_RETADDR_OFFSET < 0 | |
717 | if (UNW_SP(frame) < top | |
718 | && UNW_FP(frame) <= UNW_SP(frame) | |
719 | && bottom < UNW_FP(frame) | |
720 | # else | |
721 | if (UNW_SP(frame) > top | |
722 | && UNW_FP(frame) >= UNW_SP(frame) | |
723 | && bottom > UNW_FP(frame) | |
724 | # endif | |
725 | && !((UNW_SP(frame) | UNW_FP(frame)) | |
726 | & (sizeof(unsigned long) - 1))) { | |
727 | unsigned long link; | |
728 | ||
729 | if (!__get_user(link, | |
730 | (unsigned long *)(UNW_FP(frame) | |
731 | + FRAME_LINK_OFFSET)) | |
732 | # if FRAME_RETADDR_OFFSET < 0 | |
733 | && link > bottom && link < UNW_FP(frame) | |
734 | # else | |
735 | && link > UNW_FP(frame) && link < bottom | |
736 | # endif | |
737 | && !(link & (sizeof(link) - 1)) | |
738 | && !__get_user(UNW_PC(frame), | |
739 | (unsigned long *)(UNW_FP(frame) | |
740 | + FRAME_RETADDR_OFFSET))) { | |
741 | UNW_SP(frame) = UNW_FP(frame) + FRAME_RETADDR_OFFSET | |
742 | # if FRAME_RETADDR_OFFSET < 0 | |
743 | - | |
744 | # else | |
745 | + | |
746 | # endif | |
747 | sizeof(UNW_PC(frame)); | |
748 | UNW_FP(frame) = link; | |
749 | return 0; | |
750 | } | |
751 | } | |
752 | #endif | |
753 | return -ENXIO; | |
754 | } | |
755 | state.org = startLoc; | |
756 | memcpy(&state.cfa, &badCFA, sizeof(state.cfa)); | |
757 | /* process instructions */ | |
758 | if (!processCFI(ptr, end, UNW_PC(frame), ptrType, &state) | |
759 | || state.loc > endLoc | |
760 | || state.regs[retAddrReg].where == Nowhere | |
761 | || state.cfa.reg >= ARRAY_SIZE(reg_info) | |
762 | || reg_info[state.cfa.reg].width != sizeof(unsigned long) | |
763 | || state.cfa.offs % sizeof(unsigned long)) | |
764 | return -EIO; | |
765 | /* update frame */ | |
766 | cfa = FRAME_REG(state.cfa.reg, unsigned long) + state.cfa.offs; | |
767 | startLoc = min((unsigned long)UNW_SP(frame), cfa); | |
768 | endLoc = max((unsigned long)UNW_SP(frame), cfa); | |
769 | if (STACK_LIMIT(startLoc) != STACK_LIMIT(endLoc)) { | |
770 | startLoc = min(STACK_LIMIT(cfa), cfa); | |
771 | endLoc = max(STACK_LIMIT(cfa), cfa); | |
772 | } | |
773 | #ifndef CONFIG_64BIT | |
774 | # define CASES CASE(8); CASE(16); CASE(32) | |
775 | #else | |
776 | # define CASES CASE(8); CASE(16); CASE(32); CASE(64) | |
777 | #endif | |
778 | for (i = 0; i < ARRAY_SIZE(state.regs); ++i) { | |
779 | if (REG_INVALID(i)) { | |
780 | if (state.regs[i].where == Nowhere) | |
781 | continue; | |
782 | return -EIO; | |
783 | } | |
784 | switch(state.regs[i].where) { | |
785 | default: | |
786 | break; | |
787 | case Register: | |
788 | if (state.regs[i].value >= ARRAY_SIZE(reg_info) | |
789 | || REG_INVALID(state.regs[i].value) | |
790 | || reg_info[i].width > reg_info[state.regs[i].value].width) | |
791 | return -EIO; | |
792 | switch(reg_info[state.regs[i].value].width) { | |
793 | #define CASE(n) \ | |
794 | case sizeof(u##n): \ | |
795 | state.regs[i].value = FRAME_REG(state.regs[i].value, \ | |
796 | const u##n); \ | |
797 | break | |
798 | CASES; | |
799 | #undef CASE | |
800 | default: | |
801 | return -EIO; | |
802 | } | |
803 | break; | |
804 | } | |
805 | } | |
806 | for (i = 0; i < ARRAY_SIZE(state.regs); ++i) { | |
807 | if (REG_INVALID(i)) | |
808 | continue; | |
809 | switch(state.regs[i].where) { | |
810 | case Nowhere: | |
811 | if (reg_info[i].width != sizeof(UNW_SP(frame)) | |
812 | || &FRAME_REG(i, __typeof__(UNW_SP(frame))) | |
813 | != &UNW_SP(frame)) | |
814 | continue; | |
815 | UNW_SP(frame) = cfa; | |
816 | break; | |
817 | case Register: | |
818 | switch(reg_info[i].width) { | |
819 | #define CASE(n) case sizeof(u##n): \ | |
820 | FRAME_REG(i, u##n) = state.regs[i].value; \ | |
821 | break | |
822 | CASES; | |
823 | #undef CASE | |
824 | default: | |
825 | return -EIO; | |
826 | } | |
827 | break; | |
828 | case Value: | |
829 | if (reg_info[i].width != sizeof(unsigned long)) | |
830 | return -EIO; | |
831 | FRAME_REG(i, unsigned long) = cfa + state.regs[i].value | |
832 | * state.dataAlign; | |
833 | break; | |
834 | case Memory: { | |
835 | unsigned long addr = cfa + state.regs[i].value | |
836 | * state.dataAlign; | |
837 | ||
838 | if ((state.regs[i].value * state.dataAlign) | |
839 | % sizeof(unsigned long) | |
840 | || addr < startLoc | |
841 | || addr + sizeof(unsigned long) < addr | |
842 | || addr + sizeof(unsigned long) > endLoc) | |
843 | return -EIO; | |
844 | switch(reg_info[i].width) { | |
845 | #define CASE(n) case sizeof(u##n): \ | |
846 | __get_user(FRAME_REG(i, u##n), (u##n *)addr); \ | |
847 | break | |
848 | CASES; | |
849 | #undef CASE | |
850 | default: | |
851 | return -EIO; | |
852 | } | |
853 | } | |
854 | break; | |
855 | } | |
856 | } | |
857 | ||
858 | return 0; | |
859 | #undef CASES | |
860 | #undef FRAME_REG | |
861 | } | |
862 | EXPORT_SYMBOL(unwind); | |
863 | ||
864 | int unwind_init_frame_info(struct unwind_frame_info *info, | |
865 | struct task_struct *tsk, | |
866 | /*const*/ struct pt_regs *regs) | |
867 | { | |
868 | info->task = tsk; | |
869 | arch_unw_init_frame_info(info, regs); | |
870 | ||
871 | return 0; | |
872 | } | |
873 | EXPORT_SYMBOL(unwind_init_frame_info); | |
874 | ||
875 | /* | |
876 | * Prepare to unwind a blocked task. | |
877 | */ | |
878 | int unwind_init_blocked(struct unwind_frame_info *info, | |
879 | struct task_struct *tsk) | |
880 | { | |
881 | info->task = tsk; | |
882 | arch_unw_init_blocked(info); | |
883 | ||
884 | return 0; | |
885 | } | |
886 | EXPORT_SYMBOL(unwind_init_blocked); | |
887 | ||
888 | /* | |
889 | * Prepare to unwind the currently running thread. | |
890 | */ | |
891 | int unwind_init_running(struct unwind_frame_info *info, | |
c33bd9aa JB |
892 | asmlinkage int (*callback)(struct unwind_frame_info *, |
893 | void *arg), | |
4552d5dc JB |
894 | void *arg) |
895 | { | |
896 | info->task = current; | |
4552d5dc | 897 | |
c33bd9aa | 898 | return arch_unwind_init_running(info, callback, arg); |
4552d5dc JB |
899 | } |
900 | EXPORT_SYMBOL(unwind_init_running); | |
901 | ||
902 | /* | |
903 | * Unwind until the return pointer is in user-land (or until an error | |
904 | * occurs). Returns 0 if successful, negative number in case of | |
905 | * error. | |
906 | */ | |
907 | int unwind_to_user(struct unwind_frame_info *info) | |
908 | { | |
909 | while (!arch_unw_user_mode(info)) { | |
910 | int err = unwind(info); | |
911 | ||
912 | if (err < 0) | |
913 | return err; | |
914 | } | |
915 | ||
916 | return 0; | |
917 | } | |
918 | EXPORT_SYMBOL(unwind_to_user); |