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Merge branch 'for-linus' into for-next
[deliverable/linux.git] / arch / arc / kernel / unwind.c
1 /*
2 * Copyright (C) 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
3 * Copyright (C) 2002-2006 Novell, Inc.
4 * Jan Beulich <jbeulich@novell.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * A simple API for unwinding kernel stacks. This is used for
11 * debugging and error reporting purposes. The kernel doesn't need
12 * full-blown stack unwinding with all the bells and whistles, so there
13 * is not much point in implementing the full Dwarf2 unwind API.
14 */
15
16 #include <linux/sched.h>
17 #include <linux/module.h>
18 #include <linux/bootmem.h>
19 #include <linux/sort.h>
20 #include <linux/slab.h>
21 #include <linux/stop_machine.h>
22 #include <linux/uaccess.h>
23 #include <linux/ptrace.h>
24 #include <asm/sections.h>
25 #include <asm/unaligned.h>
26 #include <asm/unwind.h>
27
28 extern char __start_unwind[], __end_unwind[];
29 /* extern const u8 __start_unwind_hdr[], __end_unwind_hdr[];*/
30
31 /* #define UNWIND_DEBUG */
32
33 #ifdef UNWIND_DEBUG
34 int dbg_unw;
35 #define unw_debug(fmt, ...) \
36 do { \
37 if (dbg_unw) \
38 pr_info(fmt, ##__VA_ARGS__); \
39 } while (0);
40 #else
41 #define unw_debug(fmt, ...)
42 #endif
43
44 #define MAX_STACK_DEPTH 8
45
46 #define EXTRA_INFO(f) { \
47 BUILD_BUG_ON_ZERO(offsetof(struct unwind_frame_info, f) \
48 % FIELD_SIZEOF(struct unwind_frame_info, f)) \
49 + offsetof(struct unwind_frame_info, f) \
50 / FIELD_SIZEOF(struct unwind_frame_info, f), \
51 FIELD_SIZEOF(struct unwind_frame_info, f) \
52 }
53 #define PTREGS_INFO(f) EXTRA_INFO(regs.f)
54
55 static const struct {
56 unsigned offs:BITS_PER_LONG / 2;
57 unsigned width:BITS_PER_LONG / 2;
58 } reg_info[] = {
59 UNW_REGISTER_INFO};
60
61 #undef PTREGS_INFO
62 #undef EXTRA_INFO
63
64 #ifndef REG_INVALID
65 #define REG_INVALID(r) (reg_info[r].width == 0)
66 #endif
67
68 #define DW_CFA_nop 0x00
69 #define DW_CFA_set_loc 0x01
70 #define DW_CFA_advance_loc1 0x02
71 #define DW_CFA_advance_loc2 0x03
72 #define DW_CFA_advance_loc4 0x04
73 #define DW_CFA_offset_extended 0x05
74 #define DW_CFA_restore_extended 0x06
75 #define DW_CFA_undefined 0x07
76 #define DW_CFA_same_value 0x08
77 #define DW_CFA_register 0x09
78 #define DW_CFA_remember_state 0x0a
79 #define DW_CFA_restore_state 0x0b
80 #define DW_CFA_def_cfa 0x0c
81 #define DW_CFA_def_cfa_register 0x0d
82 #define DW_CFA_def_cfa_offset 0x0e
83 #define DW_CFA_def_cfa_expression 0x0f
84 #define DW_CFA_expression 0x10
85 #define DW_CFA_offset_extended_sf 0x11
86 #define DW_CFA_def_cfa_sf 0x12
87 #define DW_CFA_def_cfa_offset_sf 0x13
88 #define DW_CFA_val_offset 0x14
89 #define DW_CFA_val_offset_sf 0x15
90 #define DW_CFA_val_expression 0x16
91 #define DW_CFA_lo_user 0x1c
92 #define DW_CFA_GNU_window_save 0x2d
93 #define DW_CFA_GNU_args_size 0x2e
94 #define DW_CFA_GNU_negative_offset_extended 0x2f
95 #define DW_CFA_hi_user 0x3f
96
97 #define DW_EH_PE_FORM 0x07
98 #define DW_EH_PE_native 0x00
99 #define DW_EH_PE_leb128 0x01
100 #define DW_EH_PE_data2 0x02
101 #define DW_EH_PE_data4 0x03
102 #define DW_EH_PE_data8 0x04
103 #define DW_EH_PE_signed 0x08
104 #define DW_EH_PE_ADJUST 0x70
105 #define DW_EH_PE_abs 0x00
106 #define DW_EH_PE_pcrel 0x10
107 #define DW_EH_PE_textrel 0x20
108 #define DW_EH_PE_datarel 0x30
109 #define DW_EH_PE_funcrel 0x40
110 #define DW_EH_PE_aligned 0x50
111 #define DW_EH_PE_indirect 0x80
112 #define DW_EH_PE_omit 0xff
113
114 typedef unsigned long uleb128_t;
115 typedef signed long sleb128_t;
116
117 static struct unwind_table {
118 struct {
119 unsigned long pc;
120 unsigned long range;
121 } core, init;
122 const void *address;
123 unsigned long size;
124 const unsigned char *header;
125 unsigned long hdrsz;
126 struct unwind_table *link;
127 const char *name;
128 } root_table;
129
130 struct unwind_item {
131 enum item_location {
132 Nowhere,
133 Memory,
134 Register,
135 Value
136 } where;
137 uleb128_t value;
138 };
139
140 struct unwind_state {
141 uleb128_t loc, org;
142 const u8 *cieStart, *cieEnd;
143 uleb128_t codeAlign;
144 sleb128_t dataAlign;
145 struct cfa {
146 uleb128_t reg, offs;
147 } cfa;
148 struct unwind_item regs[ARRAY_SIZE(reg_info)];
149 unsigned stackDepth:8;
150 unsigned version:8;
151 const u8 *label;
152 const u8 *stack[MAX_STACK_DEPTH];
153 };
154
155 static const struct cfa badCFA = { ARRAY_SIZE(reg_info), 1 };
156
157 static struct unwind_table *find_table(unsigned long pc)
158 {
159 struct unwind_table *table;
160
161 for (table = &root_table; table; table = table->link)
162 if ((pc >= table->core.pc
163 && pc < table->core.pc + table->core.range)
164 || (pc >= table->init.pc
165 && pc < table->init.pc + table->init.range))
166 break;
167
168 return table;
169 }
170
171 static unsigned long read_pointer(const u8 **pLoc,
172 const void *end, signed ptrType);
173 static void init_unwind_hdr(struct unwind_table *table,
174 void *(*alloc) (unsigned long));
175
176 /*
177 * wrappers for header alloc (vs. calling one vs. other at call site)
178 * to elide section mismatches warnings
179 */
180 static void *__init unw_hdr_alloc_early(unsigned long sz)
181 {
182 return __alloc_bootmem_nopanic(sz, sizeof(unsigned int),
183 MAX_DMA_ADDRESS);
184 }
185
186 static void *unw_hdr_alloc(unsigned long sz)
187 {
188 return kmalloc(sz, GFP_KERNEL);
189 }
190
191 static void init_unwind_table(struct unwind_table *table, const char *name,
192 const void *core_start, unsigned long core_size,
193 const void *init_start, unsigned long init_size,
194 const void *table_start, unsigned long table_size,
195 const u8 *header_start, unsigned long header_size)
196 {
197 const u8 *ptr = header_start + 4;
198 const u8 *end = header_start + header_size;
199
200 table->core.pc = (unsigned long)core_start;
201 table->core.range = core_size;
202 table->init.pc = (unsigned long)init_start;
203 table->init.range = init_size;
204 table->address = table_start;
205 table->size = table_size;
206
207 /* See if the linker provided table looks valid. */
208 if (header_size <= 4
209 || header_start[0] != 1
210 || (void *)read_pointer(&ptr, end, header_start[1]) != table_start
211 || header_start[2] == DW_EH_PE_omit
212 || read_pointer(&ptr, end, header_start[2]) <= 0
213 || header_start[3] == DW_EH_PE_omit)
214 header_start = NULL;
215
216 table->hdrsz = header_size;
217 smp_wmb();
218 table->header = header_start;
219 table->link = NULL;
220 table->name = name;
221 }
222
223 void __init arc_unwind_init(void)
224 {
225 init_unwind_table(&root_table, "kernel", _text, _end - _text, NULL, 0,
226 __start_unwind, __end_unwind - __start_unwind,
227 NULL, 0);
228 /*__start_unwind_hdr, __end_unwind_hdr - __start_unwind_hdr);*/
229
230 init_unwind_hdr(&root_table, unw_hdr_alloc_early);
231 }
232
233 static const u32 bad_cie, not_fde;
234 static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *);
235 static signed fde_pointer_type(const u32 *cie);
236
237 struct eh_frame_hdr_table_entry {
238 unsigned long start, fde;
239 };
240
241 static int cmp_eh_frame_hdr_table_entries(const void *p1, const void *p2)
242 {
243 const struct eh_frame_hdr_table_entry *e1 = p1;
244 const struct eh_frame_hdr_table_entry *e2 = p2;
245
246 return (e1->start > e2->start) - (e1->start < e2->start);
247 }
248
249 static void swap_eh_frame_hdr_table_entries(void *p1, void *p2, int size)
250 {
251 struct eh_frame_hdr_table_entry *e1 = p1;
252 struct eh_frame_hdr_table_entry *e2 = p2;
253 unsigned long v;
254
255 v = e1->start;
256 e1->start = e2->start;
257 e2->start = v;
258 v = e1->fde;
259 e1->fde = e2->fde;
260 e2->fde = v;
261 }
262
263 static void init_unwind_hdr(struct unwind_table *table,
264 void *(*alloc) (unsigned long))
265 {
266 const u8 *ptr;
267 unsigned long tableSize = table->size, hdrSize;
268 unsigned n;
269 const u32 *fde;
270 struct {
271 u8 version;
272 u8 eh_frame_ptr_enc;
273 u8 fde_count_enc;
274 u8 table_enc;
275 unsigned long eh_frame_ptr;
276 unsigned int fde_count;
277 struct eh_frame_hdr_table_entry table[];
278 } __attribute__ ((__packed__)) *header;
279
280 if (table->header)
281 return;
282
283 if (table->hdrsz)
284 pr_warn(".eh_frame_hdr for '%s' present but unusable\n",
285 table->name);
286
287 if (tableSize & (sizeof(*fde) - 1))
288 return;
289
290 for (fde = table->address, n = 0;
291 tableSize > sizeof(*fde) && tableSize - sizeof(*fde) >= *fde;
292 tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) {
293 const u32 *cie = cie_for_fde(fde, table);
294 signed ptrType;
295
296 if (cie == &not_fde) /* only process FDE here */
297 continue;
298 if (cie == NULL || cie == &bad_cie)
299 continue; /* say FDE->CIE.version != 1 */
300 ptrType = fde_pointer_type(cie);
301 if (ptrType < 0)
302 continue;
303
304 ptr = (const u8 *)(fde + 2);
305 if (!read_pointer(&ptr, (const u8 *)(fde + 1) + *fde,
306 ptrType)) {
307 /* FIXME_Rajesh We have 4 instances of null addresses
308 * instead of the initial loc addr
309 * return;
310 */
311 WARN(1, "unwinder: FDE->initial_location NULL %p\n",
312 (const u8 *)(fde + 1) + *fde);
313 }
314 ++n;
315 }
316
317 if (tableSize || !n)
318 return;
319
320 hdrSize = 4 + sizeof(unsigned long) + sizeof(unsigned int)
321 + 2 * n * sizeof(unsigned long);
322
323 header = alloc(hdrSize);
324 if (!header)
325 return;
326
327 header->version = 1;
328 header->eh_frame_ptr_enc = DW_EH_PE_abs | DW_EH_PE_native;
329 header->fde_count_enc = DW_EH_PE_abs | DW_EH_PE_data4;
330 header->table_enc = DW_EH_PE_abs | DW_EH_PE_native;
331 put_unaligned((unsigned long)table->address, &header->eh_frame_ptr);
332 BUILD_BUG_ON(offsetof(typeof(*header), fde_count)
333 % __alignof(typeof(header->fde_count)));
334 header->fde_count = n;
335
336 BUILD_BUG_ON(offsetof(typeof(*header), table)
337 % __alignof(typeof(*header->table)));
338 for (fde = table->address, tableSize = table->size, n = 0;
339 tableSize;
340 tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) {
341 /* const u32 *cie = fde + 1 - fde[1] / sizeof(*fde); */
342 const u32 *cie = (const u32 *)(fde[1]);
343
344 if (fde[1] == 0xffffffff)
345 continue; /* this is a CIE */
346
347 if (*(u8 *)(cie + 2) != 1)
348 continue; /* FDE->CIE.version not supported */
349
350 ptr = (const u8 *)(fde + 2);
351 header->table[n].start = read_pointer(&ptr,
352 (const u8 *)(fde + 1) +
353 *fde,
354 fde_pointer_type(cie));
355 header->table[n].fde = (unsigned long)fde;
356 ++n;
357 }
358 WARN_ON(n != header->fde_count);
359
360 sort(header->table,
361 n,
362 sizeof(*header->table),
363 cmp_eh_frame_hdr_table_entries, swap_eh_frame_hdr_table_entries);
364
365 table->hdrsz = hdrSize;
366 smp_wmb();
367 table->header = (const void *)header;
368 }
369
370 #ifdef CONFIG_MODULES
371
372 static struct unwind_table *last_table;
373
374 /* Must be called with module_mutex held. */
375 void *unwind_add_table(struct module *module, const void *table_start,
376 unsigned long table_size)
377 {
378 struct unwind_table *table;
379
380 if (table_size <= 0)
381 return NULL;
382
383 table = kmalloc(sizeof(*table), GFP_KERNEL);
384 if (!table)
385 return NULL;
386
387 init_unwind_table(table, module->name,
388 module->module_core, module->core_size,
389 module->module_init, module->init_size,
390 table_start, table_size,
391 NULL, 0);
392
393 init_unwind_hdr(table, unw_hdr_alloc);
394
395 #ifdef UNWIND_DEBUG
396 unw_debug("Table added for [%s] %lx %lx\n",
397 module->name, table->core.pc, table->core.range);
398 #endif
399 if (last_table)
400 last_table->link = table;
401 else
402 root_table.link = table;
403 last_table = table;
404
405 return table;
406 }
407
408 struct unlink_table_info {
409 struct unwind_table *table;
410 int init_only;
411 };
412
413 static int unlink_table(void *arg)
414 {
415 struct unlink_table_info *info = arg;
416 struct unwind_table *table = info->table, *prev;
417
418 for (prev = &root_table; prev->link && prev->link != table;
419 prev = prev->link)
420 ;
421
422 if (prev->link) {
423 if (info->init_only) {
424 table->init.pc = 0;
425 table->init.range = 0;
426 info->table = NULL;
427 } else {
428 prev->link = table->link;
429 if (!prev->link)
430 last_table = prev;
431 }
432 } else
433 info->table = NULL;
434
435 return 0;
436 }
437
438 /* Must be called with module_mutex held. */
439 void unwind_remove_table(void *handle, int init_only)
440 {
441 struct unwind_table *table = handle;
442 struct unlink_table_info info;
443
444 if (!table || table == &root_table)
445 return;
446
447 if (init_only && table == last_table) {
448 table->init.pc = 0;
449 table->init.range = 0;
450 return;
451 }
452
453 info.table = table;
454 info.init_only = init_only;
455
456 unlink_table(&info); /* XXX: SMP */
457 kfree(table->header);
458 kfree(table);
459 }
460
461 #endif /* CONFIG_MODULES */
462
463 static uleb128_t get_uleb128(const u8 **pcur, const u8 *end)
464 {
465 const u8 *cur = *pcur;
466 uleb128_t value;
467 unsigned shift;
468
469 for (shift = 0, value = 0; cur < end; shift += 7) {
470 if (shift + 7 > 8 * sizeof(value)
471 && (*cur & 0x7fU) >= (1U << (8 * sizeof(value) - shift))) {
472 cur = end + 1;
473 break;
474 }
475 value |= (uleb128_t) (*cur & 0x7f) << shift;
476 if (!(*cur++ & 0x80))
477 break;
478 }
479 *pcur = cur;
480
481 return value;
482 }
483
484 static sleb128_t get_sleb128(const u8 **pcur, const u8 *end)
485 {
486 const u8 *cur = *pcur;
487 sleb128_t value;
488 unsigned shift;
489
490 for (shift = 0, value = 0; cur < end; shift += 7) {
491 if (shift + 7 > 8 * sizeof(value)
492 && (*cur & 0x7fU) >= (1U << (8 * sizeof(value) - shift))) {
493 cur = end + 1;
494 break;
495 }
496 value |= (sleb128_t) (*cur & 0x7f) << shift;
497 if (!(*cur & 0x80)) {
498 value |= -(*cur++ & 0x40) << shift;
499 break;
500 }
501 }
502 *pcur = cur;
503
504 return value;
505 }
506
507 static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *table)
508 {
509 const u32 *cie;
510
511 if (!*fde || (*fde & (sizeof(*fde) - 1)))
512 return &bad_cie;
513
514 if (fde[1] == 0xffffffff)
515 return &not_fde; /* this is a CIE */
516
517 if ((fde[1] & (sizeof(*fde) - 1)))
518 /* || fde[1] > (unsigned long)(fde + 1) - (unsigned long)table->address) */
519 return NULL; /* this is not a valid FDE */
520
521 /* cie = fde + 1 - fde[1] / sizeof(*fde); */
522 cie = (u32 *) fde[1];
523
524 if (*cie <= sizeof(*cie) + 4 || *cie >= fde[1] - sizeof(*fde)
525 || (*cie & (sizeof(*cie) - 1))
526 || (cie[1] != 0xffffffff)
527 || ( *(u8 *)(cie + 2) != 1)) /* version 1 supported */
528 return NULL; /* this is not a (valid) CIE */
529 return cie;
530 }
531
532 static unsigned long read_pointer(const u8 **pLoc, const void *end,
533 signed ptrType)
534 {
535 unsigned long value = 0;
536 union {
537 const u8 *p8;
538 const u16 *p16u;
539 const s16 *p16s;
540 const u32 *p32u;
541 const s32 *p32s;
542 const unsigned long *pul;
543 } ptr;
544
545 if (ptrType < 0 || ptrType == DW_EH_PE_omit)
546 return 0;
547 ptr.p8 = *pLoc;
548 switch (ptrType & DW_EH_PE_FORM) {
549 case DW_EH_PE_data2:
550 if (end < (const void *)(ptr.p16u + 1))
551 return 0;
552 if (ptrType & DW_EH_PE_signed)
553 value = get_unaligned((u16 *) ptr.p16s++);
554 else
555 value = get_unaligned((u16 *) ptr.p16u++);
556 break;
557 case DW_EH_PE_data4:
558 #ifdef CONFIG_64BIT
559 if (end < (const void *)(ptr.p32u + 1))
560 return 0;
561 if (ptrType & DW_EH_PE_signed)
562 value = get_unaligned(ptr.p32s++);
563 else
564 value = get_unaligned(ptr.p32u++);
565 break;
566 case DW_EH_PE_data8:
567 BUILD_BUG_ON(sizeof(u64) != sizeof(value));
568 #else
569 BUILD_BUG_ON(sizeof(u32) != sizeof(value));
570 #endif
571 case DW_EH_PE_native:
572 if (end < (const void *)(ptr.pul + 1))
573 return 0;
574 value = get_unaligned((unsigned long *)ptr.pul++);
575 break;
576 case DW_EH_PE_leb128:
577 BUILD_BUG_ON(sizeof(uleb128_t) > sizeof(value));
578 value = ptrType & DW_EH_PE_signed ? get_sleb128(&ptr.p8, end)
579 : get_uleb128(&ptr.p8, end);
580 if ((const void *)ptr.p8 > end)
581 return 0;
582 break;
583 default:
584 return 0;
585 }
586 switch (ptrType & DW_EH_PE_ADJUST) {
587 case DW_EH_PE_abs:
588 break;
589 case DW_EH_PE_pcrel:
590 value += (unsigned long)*pLoc;
591 break;
592 default:
593 return 0;
594 }
595 if ((ptrType & DW_EH_PE_indirect)
596 && __get_user(value, (unsigned long __user *)value))
597 return 0;
598 *pLoc = ptr.p8;
599
600 return value;
601 }
602
603 static signed fde_pointer_type(const u32 *cie)
604 {
605 const u8 *ptr = (const u8 *)(cie + 2);
606 unsigned version = *ptr;
607
608 if (version != 1)
609 return -1; /* unsupported */
610
611 if (*++ptr) {
612 const char *aug;
613 const u8 *end = (const u8 *)(cie + 1) + *cie;
614 uleb128_t len;
615
616 /* check if augmentation size is first (and thus present) */
617 if (*ptr != 'z')
618 return -1;
619
620 /* check if augmentation string is nul-terminated */
621 aug = (const void *)ptr;
622 ptr = memchr(aug, 0, end - ptr);
623 if (ptr == NULL)
624 return -1;
625
626 ++ptr; /* skip terminator */
627 get_uleb128(&ptr, end); /* skip code alignment */
628 get_sleb128(&ptr, end); /* skip data alignment */
629 /* skip return address column */
630 version <= 1 ? (void) ++ptr : (void)get_uleb128(&ptr, end);
631 len = get_uleb128(&ptr, end); /* augmentation length */
632
633 if (ptr + len < ptr || ptr + len > end)
634 return -1;
635
636 end = ptr + len;
637 while (*++aug) {
638 if (ptr >= end)
639 return -1;
640 switch (*aug) {
641 case 'L':
642 ++ptr;
643 break;
644 case 'P':{
645 signed ptrType = *ptr++;
646
647 if (!read_pointer(&ptr, end, ptrType)
648 || ptr > end)
649 return -1;
650 }
651 break;
652 case 'R':
653 return *ptr;
654 default:
655 return -1;
656 }
657 }
658 }
659 return DW_EH_PE_native | DW_EH_PE_abs;
660 }
661
662 static int advance_loc(unsigned long delta, struct unwind_state *state)
663 {
664 state->loc += delta * state->codeAlign;
665
666 /* FIXME_Rajesh: Probably we are defining for the initial range as well;
667 return delta > 0;
668 */
669 unw_debug("delta %3lu => loc 0x%lx: ", delta, state->loc);
670 return 1;
671 }
672
673 static void set_rule(uleb128_t reg, enum item_location where, uleb128_t value,
674 struct unwind_state *state)
675 {
676 if (reg < ARRAY_SIZE(state->regs)) {
677 state->regs[reg].where = where;
678 state->regs[reg].value = value;
679
680 #ifdef UNWIND_DEBUG
681 unw_debug("r%lu: ", reg);
682 switch (where) {
683 case Nowhere:
684 unw_debug("s ");
685 break;
686 case Memory:
687 unw_debug("c(%lu) ", value);
688 break;
689 case Register:
690 unw_debug("r(%lu) ", value);
691 break;
692 case Value:
693 unw_debug("v(%lu) ", value);
694 break;
695 default:
696 break;
697 }
698 #endif
699 }
700 }
701
702 static int processCFI(const u8 *start, const u8 *end, unsigned long targetLoc,
703 signed ptrType, struct unwind_state *state)
704 {
705 union {
706 const u8 *p8;
707 const u16 *p16;
708 const u32 *p32;
709 } ptr;
710 int result = 1;
711 u8 opcode;
712
713 if (start != state->cieStart) {
714 state->loc = state->org;
715 result =
716 processCFI(state->cieStart, state->cieEnd, 0, ptrType,
717 state);
718 if (targetLoc == 0 && state->label == NULL)
719 return result;
720 }
721 for (ptr.p8 = start; result && ptr.p8 < end;) {
722 switch (*ptr.p8 >> 6) {
723 uleb128_t value;
724
725 case 0:
726 opcode = *ptr.p8++;
727
728 switch (opcode) {
729 case DW_CFA_nop:
730 unw_debug("cfa nop ");
731 break;
732 case DW_CFA_set_loc:
733 state->loc = read_pointer(&ptr.p8, end,
734 ptrType);
735 if (state->loc == 0)
736 result = 0;
737 unw_debug("cfa_set_loc: 0x%lx ", state->loc);
738 break;
739 case DW_CFA_advance_loc1:
740 unw_debug("\ncfa advance loc1:");
741 result = ptr.p8 < end
742 && advance_loc(*ptr.p8++, state);
743 break;
744 case DW_CFA_advance_loc2:
745 value = *ptr.p8++;
746 value += *ptr.p8++ << 8;
747 unw_debug("\ncfa advance loc2:");
748 result = ptr.p8 <= end + 2
749 /* && advance_loc(*ptr.p16++, state); */
750 && advance_loc(value, state);
751 break;
752 case DW_CFA_advance_loc4:
753 unw_debug("\ncfa advance loc4:");
754 result = ptr.p8 <= end + 4
755 && advance_loc(*ptr.p32++, state);
756 break;
757 case DW_CFA_offset_extended:
758 value = get_uleb128(&ptr.p8, end);
759 unw_debug("cfa_offset_extended: ");
760 set_rule(value, Memory,
761 get_uleb128(&ptr.p8, end), state);
762 break;
763 case DW_CFA_val_offset:
764 value = get_uleb128(&ptr.p8, end);
765 set_rule(value, Value,
766 get_uleb128(&ptr.p8, end), state);
767 break;
768 case DW_CFA_offset_extended_sf:
769 value = get_uleb128(&ptr.p8, end);
770 set_rule(value, Memory,
771 get_sleb128(&ptr.p8, end), state);
772 break;
773 case DW_CFA_val_offset_sf:
774 value = get_uleb128(&ptr.p8, end);
775 set_rule(value, Value,
776 get_sleb128(&ptr.p8, end), state);
777 break;
778 case DW_CFA_restore_extended:
779 unw_debug("cfa_restore_extended: ");
780 case DW_CFA_undefined:
781 unw_debug("cfa_undefined: ");
782 case DW_CFA_same_value:
783 unw_debug("cfa_same_value: ");
784 set_rule(get_uleb128(&ptr.p8, end), Nowhere, 0,
785 state);
786 break;
787 case DW_CFA_register:
788 unw_debug("cfa_register: ");
789 value = get_uleb128(&ptr.p8, end);
790 set_rule(value,
791 Register,
792 get_uleb128(&ptr.p8, end), state);
793 break;
794 case DW_CFA_remember_state:
795 unw_debug("cfa_remember_state: ");
796 if (ptr.p8 == state->label) {
797 state->label = NULL;
798 return 1;
799 }
800 if (state->stackDepth >= MAX_STACK_DEPTH)
801 return 0;
802 state->stack[state->stackDepth++] = ptr.p8;
803 break;
804 case DW_CFA_restore_state:
805 unw_debug("cfa_restore_state: ");
806 if (state->stackDepth) {
807 const uleb128_t loc = state->loc;
808 const u8 *label = state->label;
809
810 state->label =
811 state->stack[state->stackDepth - 1];
812 memcpy(&state->cfa, &badCFA,
813 sizeof(state->cfa));
814 memset(state->regs, 0,
815 sizeof(state->regs));
816 state->stackDepth = 0;
817 result =
818 processCFI(start, end, 0, ptrType,
819 state);
820 state->loc = loc;
821 state->label = label;
822 } else
823 return 0;
824 break;
825 case DW_CFA_def_cfa:
826 state->cfa.reg = get_uleb128(&ptr.p8, end);
827 unw_debug("cfa_def_cfa: r%lu ", state->cfa.reg);
828 /*nobreak*/
829 case DW_CFA_def_cfa_offset:
830 state->cfa.offs = get_uleb128(&ptr.p8, end);
831 unw_debug("cfa_def_cfa_offset: 0x%lx ",
832 state->cfa.offs);
833 break;
834 case DW_CFA_def_cfa_sf:
835 state->cfa.reg = get_uleb128(&ptr.p8, end);
836 /*nobreak */
837 case DW_CFA_def_cfa_offset_sf:
838 state->cfa.offs = get_sleb128(&ptr.p8, end)
839 * state->dataAlign;
840 break;
841 case DW_CFA_def_cfa_register:
842 unw_debug("cfa_def_cfa_regsiter: ");
843 state->cfa.reg = get_uleb128(&ptr.p8, end);
844 break;
845 /*todo case DW_CFA_def_cfa_expression: */
846 /*todo case DW_CFA_expression: */
847 /*todo case DW_CFA_val_expression: */
848 case DW_CFA_GNU_args_size:
849 get_uleb128(&ptr.p8, end);
850 break;
851 case DW_CFA_GNU_negative_offset_extended:
852 value = get_uleb128(&ptr.p8, end);
853 set_rule(value,
854 Memory,
855 (uleb128_t) 0 - get_uleb128(&ptr.p8,
856 end),
857 state);
858 break;
859 case DW_CFA_GNU_window_save:
860 default:
861 unw_debug("UNKNOWN OPCODE 0x%x\n", opcode);
862 result = 0;
863 break;
864 }
865 break;
866 case 1:
867 unw_debug("\ncfa_adv_loc: ");
868 result = advance_loc(*ptr.p8++ & 0x3f, state);
869 break;
870 case 2:
871 unw_debug("cfa_offset: ");
872 value = *ptr.p8++ & 0x3f;
873 set_rule(value, Memory, get_uleb128(&ptr.p8, end),
874 state);
875 break;
876 case 3:
877 unw_debug("cfa_restore: ");
878 set_rule(*ptr.p8++ & 0x3f, Nowhere, 0, state);
879 break;
880 }
881
882 if (ptr.p8 > end)
883 result = 0;
884 if (result && targetLoc != 0 && targetLoc < state->loc)
885 return 1;
886 }
887
888 return result && ptr.p8 == end && (targetLoc == 0 || (
889 /*todo While in theory this should apply, gcc in practice omits
890 everything past the function prolog, and hence the location
891 never reaches the end of the function.
892 targetLoc < state->loc && */ state->label == NULL));
893 }
894
895 /* Unwind to previous to frame. Returns 0 if successful, negative
896 * number in case of an error. */
897 int arc_unwind(struct unwind_frame_info *frame)
898 {
899 #define FRAME_REG(r, t) (((t *)frame)[reg_info[r].offs])
900 const u32 *fde = NULL, *cie = NULL;
901 const u8 *ptr = NULL, *end = NULL;
902 unsigned long pc = UNW_PC(frame) - frame->call_frame;
903 unsigned long startLoc = 0, endLoc = 0, cfa;
904 unsigned i;
905 signed ptrType = -1;
906 uleb128_t retAddrReg = 0;
907 const struct unwind_table *table;
908 struct unwind_state state;
909 unsigned long *fptr;
910 unsigned long addr;
911
912 unw_debug("\n\nUNWIND FRAME:\n");
913 unw_debug("PC: 0x%lx BLINK: 0x%lx, SP: 0x%lx, FP: 0x%x\n",
914 UNW_PC(frame), UNW_BLINK(frame), UNW_SP(frame),
915 UNW_FP(frame));
916
917 if (UNW_PC(frame) == 0)
918 return -EINVAL;
919
920 #ifdef UNWIND_DEBUG
921 {
922 unsigned long *sptr = (unsigned long *)UNW_SP(frame);
923 unw_debug("\nStack Dump:\n");
924 for (i = 0; i < 20; i++, sptr++)
925 unw_debug("0x%p: 0x%lx\n", sptr, *sptr);
926 unw_debug("\n");
927 }
928 #endif
929
930 table = find_table(pc);
931 if (table != NULL
932 && !(table->size & (sizeof(*fde) - 1))) {
933 const u8 *hdr = table->header;
934 unsigned long tableSize;
935
936 smp_rmb();
937 if (hdr && hdr[0] == 1) {
938 switch (hdr[3] & DW_EH_PE_FORM) {
939 case DW_EH_PE_native:
940 tableSize = sizeof(unsigned long);
941 break;
942 case DW_EH_PE_data2:
943 tableSize = 2;
944 break;
945 case DW_EH_PE_data4:
946 tableSize = 4;
947 break;
948 case DW_EH_PE_data8:
949 tableSize = 8;
950 break;
951 default:
952 tableSize = 0;
953 break;
954 }
955 ptr = hdr + 4;
956 end = hdr + table->hdrsz;
957 if (tableSize && read_pointer(&ptr, end, hdr[1])
958 == (unsigned long)table->address
959 && (i = read_pointer(&ptr, end, hdr[2])) > 0
960 && i == (end - ptr) / (2 * tableSize)
961 && !((end - ptr) % (2 * tableSize))) {
962 do {
963 const u8 *cur =
964 ptr + (i / 2) * (2 * tableSize);
965
966 startLoc = read_pointer(&cur,
967 cur + tableSize,
968 hdr[3]);
969 if (pc < startLoc)
970 i /= 2;
971 else {
972 ptr = cur - tableSize;
973 i = (i + 1) / 2;
974 }
975 } while (startLoc && i > 1);
976 if (i == 1
977 && (startLoc = read_pointer(&ptr,
978 ptr + tableSize,
979 hdr[3])) != 0
980 && pc >= startLoc)
981 fde = (void *)read_pointer(&ptr,
982 ptr +
983 tableSize,
984 hdr[3]);
985 }
986 }
987
988 if (fde != NULL) {
989 cie = cie_for_fde(fde, table);
990 ptr = (const u8 *)(fde + 2);
991 if (cie != NULL
992 && cie != &bad_cie
993 && cie != &not_fde
994 && (ptrType = fde_pointer_type(cie)) >= 0
995 && read_pointer(&ptr,
996 (const u8 *)(fde + 1) + *fde,
997 ptrType) == startLoc) {
998 if (!(ptrType & DW_EH_PE_indirect))
999 ptrType &=
1000 DW_EH_PE_FORM | DW_EH_PE_signed;
1001 endLoc =
1002 startLoc + read_pointer(&ptr,
1003 (const u8 *)(fde +
1004 1) +
1005 *fde, ptrType);
1006 if (pc >= endLoc) {
1007 fde = NULL;
1008 cie = NULL;
1009 }
1010 } else {
1011 fde = NULL;
1012 cie = NULL;
1013 }
1014 }
1015 }
1016 if (cie != NULL) {
1017 memset(&state, 0, sizeof(state));
1018 state.cieEnd = ptr; /* keep here temporarily */
1019 ptr = (const u8 *)(cie + 2);
1020 end = (const u8 *)(cie + 1) + *cie;
1021 frame->call_frame = 1;
1022 if ((state.version = *ptr) != 1)
1023 cie = NULL; /* unsupported version */
1024 else if (*++ptr) {
1025 /* check if augmentation size is first (thus present) */
1026 if (*ptr == 'z') {
1027 while (++ptr < end && *ptr) {
1028 switch (*ptr) {
1029 /* chk for ignorable or already handled
1030 * nul-terminated augmentation string */
1031 case 'L':
1032 case 'P':
1033 case 'R':
1034 continue;
1035 case 'S':
1036 frame->call_frame = 0;
1037 continue;
1038 default:
1039 break;
1040 }
1041 break;
1042 }
1043 }
1044 if (ptr >= end || *ptr)
1045 cie = NULL;
1046 }
1047 ++ptr;
1048 }
1049 if (cie != NULL) {
1050 /* get code aligment factor */
1051 state.codeAlign = get_uleb128(&ptr, end);
1052 /* get data aligment factor */
1053 state.dataAlign = get_sleb128(&ptr, end);
1054 if (state.codeAlign == 0 || state.dataAlign == 0 || ptr >= end)
1055 cie = NULL;
1056 else {
1057 retAddrReg =
1058 state.version <= 1 ? *ptr++ : get_uleb128(&ptr,
1059 end);
1060 unw_debug("CIE Frame Info:\n");
1061 unw_debug("return Address register 0x%lx\n",
1062 retAddrReg);
1063 unw_debug("data Align: %ld\n", state.dataAlign);
1064 unw_debug("code Align: %lu\n", state.codeAlign);
1065 /* skip augmentation */
1066 if (((const char *)(cie + 2))[1] == 'z') {
1067 uleb128_t augSize = get_uleb128(&ptr, end);
1068
1069 ptr += augSize;
1070 }
1071 if (ptr > end || retAddrReg >= ARRAY_SIZE(reg_info)
1072 || REG_INVALID(retAddrReg)
1073 || reg_info[retAddrReg].width !=
1074 sizeof(unsigned long))
1075 cie = NULL;
1076 }
1077 }
1078 if (cie != NULL) {
1079 state.cieStart = ptr;
1080 ptr = state.cieEnd;
1081 state.cieEnd = end;
1082 end = (const u8 *)(fde + 1) + *fde;
1083 /* skip augmentation */
1084 if (((const char *)(cie + 2))[1] == 'z') {
1085 uleb128_t augSize = get_uleb128(&ptr, end);
1086
1087 if ((ptr += augSize) > end)
1088 fde = NULL;
1089 }
1090 }
1091 if (cie == NULL || fde == NULL) {
1092 #ifdef CONFIG_FRAME_POINTER
1093 unsigned long top, bottom;
1094
1095 top = STACK_TOP_UNW(frame->task);
1096 bottom = STACK_BOTTOM_UNW(frame->task);
1097 #if FRAME_RETADDR_OFFSET < 0
1098 if (UNW_SP(frame) < top && UNW_FP(frame) <= UNW_SP(frame)
1099 && bottom < UNW_FP(frame)
1100 #else
1101 if (UNW_SP(frame) > top && UNW_FP(frame) >= UNW_SP(frame)
1102 && bottom > UNW_FP(frame)
1103 #endif
1104 && !((UNW_SP(frame) | UNW_FP(frame))
1105 & (sizeof(unsigned long) - 1))) {
1106 unsigned long link;
1107
1108 if (!__get_user(link, (unsigned long *)
1109 (UNW_FP(frame) + FRAME_LINK_OFFSET))
1110 #if FRAME_RETADDR_OFFSET < 0
1111 && link > bottom && link < UNW_FP(frame)
1112 #else
1113 && link > UNW_FP(frame) && link < bottom
1114 #endif
1115 && !(link & (sizeof(link) - 1))
1116 && !__get_user(UNW_PC(frame),
1117 (unsigned long *)(UNW_FP(frame)
1118 + FRAME_RETADDR_OFFSET)))
1119 {
1120 UNW_SP(frame) =
1121 UNW_FP(frame) + FRAME_RETADDR_OFFSET
1122 #if FRAME_RETADDR_OFFSET < 0
1123 -
1124 #else
1125 +
1126 #endif
1127 sizeof(UNW_PC(frame));
1128 UNW_FP(frame) = link;
1129 return 0;
1130 }
1131 }
1132 #endif
1133 return -ENXIO;
1134 }
1135 state.org = startLoc;
1136 memcpy(&state.cfa, &badCFA, sizeof(state.cfa));
1137
1138 unw_debug("\nProcess instructions\n");
1139
1140 /* process instructions
1141 * For ARC, we optimize by having blink(retAddrReg) with
1142 * the sameValue in the leaf function, so we should not check
1143 * state.regs[retAddrReg].where == Nowhere
1144 */
1145 if (!processCFI(ptr, end, pc, ptrType, &state)
1146 || state.loc > endLoc
1147 /* || state.regs[retAddrReg].where == Nowhere */
1148 || state.cfa.reg >= ARRAY_SIZE(reg_info)
1149 || reg_info[state.cfa.reg].width != sizeof(unsigned long)
1150 || state.cfa.offs % sizeof(unsigned long))
1151 return -EIO;
1152
1153 #ifdef UNWIND_DEBUG
1154 unw_debug("\n");
1155
1156 unw_debug("\nRegister State Based on the rules parsed from FDE:\n");
1157 for (i = 0; i < ARRAY_SIZE(state.regs); ++i) {
1158
1159 if (REG_INVALID(i))
1160 continue;
1161
1162 switch (state.regs[i].where) {
1163 case Nowhere:
1164 break;
1165 case Memory:
1166 unw_debug(" r%d: c(%lu),", i, state.regs[i].value);
1167 break;
1168 case Register:
1169 unw_debug(" r%d: r(%lu),", i, state.regs[i].value);
1170 break;
1171 case Value:
1172 unw_debug(" r%d: v(%lu),", i, state.regs[i].value);
1173 break;
1174 }
1175 }
1176
1177 unw_debug("\n");
1178 #endif
1179
1180 /* update frame */
1181 #ifndef CONFIG_AS_CFI_SIGNAL_FRAME
1182 if (frame->call_frame
1183 && !UNW_DEFAULT_RA(state.regs[retAddrReg], state.dataAlign))
1184 frame->call_frame = 0;
1185 #endif
1186 cfa = FRAME_REG(state.cfa.reg, unsigned long) + state.cfa.offs;
1187 startLoc = min_t(unsigned long, UNW_SP(frame), cfa);
1188 endLoc = max_t(unsigned long, UNW_SP(frame), cfa);
1189 if (STACK_LIMIT(startLoc) != STACK_LIMIT(endLoc)) {
1190 startLoc = min(STACK_LIMIT(cfa), cfa);
1191 endLoc = max(STACK_LIMIT(cfa), cfa);
1192 }
1193
1194 unw_debug("\nCFA reg: 0x%lx, offset: 0x%lx => 0x%lx\n",
1195 state.cfa.reg, state.cfa.offs, cfa);
1196
1197 for (i = 0; i < ARRAY_SIZE(state.regs); ++i) {
1198 if (REG_INVALID(i)) {
1199 if (state.regs[i].where == Nowhere)
1200 continue;
1201 return -EIO;
1202 }
1203 switch (state.regs[i].where) {
1204 default:
1205 break;
1206 case Register:
1207 if (state.regs[i].value >= ARRAY_SIZE(reg_info)
1208 || REG_INVALID(state.regs[i].value)
1209 || reg_info[i].width >
1210 reg_info[state.regs[i].value].width)
1211 return -EIO;
1212 switch (reg_info[state.regs[i].value].width) {
1213 case sizeof(u8):
1214 state.regs[i].value =
1215 FRAME_REG(state.regs[i].value, const u8);
1216 break;
1217 case sizeof(u16):
1218 state.regs[i].value =
1219 FRAME_REG(state.regs[i].value, const u16);
1220 break;
1221 case sizeof(u32):
1222 state.regs[i].value =
1223 FRAME_REG(state.regs[i].value, const u32);
1224 break;
1225 #ifdef CONFIG_64BIT
1226 case sizeof(u64):
1227 state.regs[i].value =
1228 FRAME_REG(state.regs[i].value, const u64);
1229 break;
1230 #endif
1231 default:
1232 return -EIO;
1233 }
1234 break;
1235 }
1236 }
1237
1238 unw_debug("\nRegister state after evaluation with realtime Stack:\n");
1239 fptr = (unsigned long *)(&frame->regs);
1240 for (i = 0; i < ARRAY_SIZE(state.regs); ++i, fptr++) {
1241
1242 if (REG_INVALID(i))
1243 continue;
1244 switch (state.regs[i].where) {
1245 case Nowhere:
1246 if (reg_info[i].width != sizeof(UNW_SP(frame))
1247 || &FRAME_REG(i, __typeof__(UNW_SP(frame)))
1248 != &UNW_SP(frame))
1249 continue;
1250 UNW_SP(frame) = cfa;
1251 break;
1252 case Register:
1253 switch (reg_info[i].width) {
1254 case sizeof(u8):
1255 FRAME_REG(i, u8) = state.regs[i].value;
1256 break;
1257 case sizeof(u16):
1258 FRAME_REG(i, u16) = state.regs[i].value;
1259 break;
1260 case sizeof(u32):
1261 FRAME_REG(i, u32) = state.regs[i].value;
1262 break;
1263 #ifdef CONFIG_64BIT
1264 case sizeof(u64):
1265 FRAME_REG(i, u64) = state.regs[i].value;
1266 break;
1267 #endif
1268 default:
1269 return -EIO;
1270 }
1271 break;
1272 case Value:
1273 if (reg_info[i].width != sizeof(unsigned long))
1274 return -EIO;
1275 FRAME_REG(i, unsigned long) = cfa + state.regs[i].value
1276 * state.dataAlign;
1277 break;
1278 case Memory:
1279 addr = cfa + state.regs[i].value * state.dataAlign;
1280
1281 if ((state.regs[i].value * state.dataAlign)
1282 % sizeof(unsigned long)
1283 || addr < startLoc
1284 || addr + sizeof(unsigned long) < addr
1285 || addr + sizeof(unsigned long) > endLoc)
1286 return -EIO;
1287
1288 switch (reg_info[i].width) {
1289 case sizeof(u8):
1290 __get_user(FRAME_REG(i, u8),
1291 (u8 __user *)addr);
1292 break;
1293 case sizeof(u16):
1294 __get_user(FRAME_REG(i, u16),
1295 (u16 __user *)addr);
1296 break;
1297 case sizeof(u32):
1298 __get_user(FRAME_REG(i, u32),
1299 (u32 __user *)addr);
1300 break;
1301 #ifdef CONFIG_64BIT
1302 case sizeof(u64):
1303 __get_user(FRAME_REG(i, u64),
1304 (u64 __user *)addr);
1305 break;
1306 #endif
1307 default:
1308 return -EIO;
1309 }
1310
1311 break;
1312 }
1313 unw_debug("r%d: 0x%lx ", i, *fptr);
1314 }
1315
1316 return 0;
1317 #undef FRAME_REG
1318 }
1319 EXPORT_SYMBOL(arc_unwind);
Linux kernel - Deliverables
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