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1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
4 * Copyright (C) 2002-2006 Novell, Inc.
5 * Jan Beulich <jbeulich@novell.com>
6 *
7 * A simple API for unwinding kernel stacks. This is used for
8 * debugging and error reporting purposes. The kernel doesn't need
9 * full-blown stack unwinding with all the bells and whistles, so there
10 * is not much point in implementing the full Dwarf2 unwind API.
11 */
12
13 #include <linux/sched.h>
14 #include <linux/module.h>
15 #include <linux/memblock.h>
16 #include <linux/sort.h>
17 #include <linux/slab.h>
18 #include <linux/stop_machine.h>
19 #include <linux/uaccess.h>
20 #include <linux/ptrace.h>
21 #include <asm/sections.h>
22 #include <asm/unaligned.h>
23 #include <asm/unwind.h>
24
25 extern char __start_unwind[], __end_unwind[];
26 /* extern const u8 __start_unwind_hdr[], __end_unwind_hdr[];*/
27
28 /* #define UNWIND_DEBUG */
29
30 #ifdef UNWIND_DEBUG
31 int dbg_unw;
32 #define unw_debug(fmt, ...) \
33 do { \
34 if (dbg_unw) \
35 pr_info(fmt, ##__VA_ARGS__); \
36 } while (0);
37 #else
38 #define unw_debug(fmt, ...)
39 #endif
40
41 #define MAX_STACK_DEPTH 8
42
43 #define EXTRA_INFO(f) { \
44 BUILD_BUG_ON_ZERO(offsetof(struct unwind_frame_info, f) \
45 % FIELD_SIZEOF(struct unwind_frame_info, f)) \
46 + offsetof(struct unwind_frame_info, f) \
47 / FIELD_SIZEOF(struct unwind_frame_info, f), \
48 FIELD_SIZEOF(struct unwind_frame_info, f) \
49 }
50 #define PTREGS_INFO(f) EXTRA_INFO(regs.f)
51
52 static const struct {
53 unsigned offs:BITS_PER_LONG / 2;
54 unsigned width:BITS_PER_LONG / 2;
55 } reg_info[] = {
56 UNW_REGISTER_INFO};
57
58 #undef PTREGS_INFO
59 #undef EXTRA_INFO
60
61 #ifndef REG_INVALID
62 #define REG_INVALID(r) (reg_info[r].width == 0)
63 #endif
64
65 #define DW_CFA_nop 0x00
66 #define DW_CFA_set_loc 0x01
67 #define DW_CFA_advance_loc1 0x02
68 #define DW_CFA_advance_loc2 0x03
69 #define DW_CFA_advance_loc4 0x04
70 #define DW_CFA_offset_extended 0x05
71 #define DW_CFA_restore_extended 0x06
72 #define DW_CFA_undefined 0x07
73 #define DW_CFA_same_value 0x08
74 #define DW_CFA_register 0x09
75 #define DW_CFA_remember_state 0x0a
76 #define DW_CFA_restore_state 0x0b
77 #define DW_CFA_def_cfa 0x0c
78 #define DW_CFA_def_cfa_register 0x0d
79 #define DW_CFA_def_cfa_offset 0x0e
80 #define DW_CFA_def_cfa_expression 0x0f
81 #define DW_CFA_expression 0x10
82 #define DW_CFA_offset_extended_sf 0x11
83 #define DW_CFA_def_cfa_sf 0x12
84 #define DW_CFA_def_cfa_offset_sf 0x13
85 #define DW_CFA_val_offset 0x14
86 #define DW_CFA_val_offset_sf 0x15
87 #define DW_CFA_val_expression 0x16
88 #define DW_CFA_lo_user 0x1c
89 #define DW_CFA_GNU_window_save 0x2d
90 #define DW_CFA_GNU_args_size 0x2e
91 #define DW_CFA_GNU_negative_offset_extended 0x2f
92 #define DW_CFA_hi_user 0x3f
93
94 #define DW_EH_PE_FORM 0x07
95 #define DW_EH_PE_native 0x00
96 #define DW_EH_PE_leb128 0x01
97 #define DW_EH_PE_data2 0x02
98 #define DW_EH_PE_data4 0x03
99 #define DW_EH_PE_data8 0x04
100 #define DW_EH_PE_signed 0x08
101 #define DW_EH_PE_ADJUST 0x70
102 #define DW_EH_PE_abs 0x00
103 #define DW_EH_PE_pcrel 0x10
104 #define DW_EH_PE_textrel 0x20
105 #define DW_EH_PE_datarel 0x30
106 #define DW_EH_PE_funcrel 0x40
107 #define DW_EH_PE_aligned 0x50
108 #define DW_EH_PE_indirect 0x80
109 #define DW_EH_PE_omit 0xff
110
111 #define CIE_ID 0
112
113 typedef unsigned long uleb128_t;
114 typedef signed long sleb128_t;
115
116 static struct unwind_table {
117 struct {
118 unsigned long pc;
119 unsigned long range;
120 } core, init;
121 const void *address;
122 unsigned long size;
123 const unsigned char *header;
124 unsigned long hdrsz;
125 struct unwind_table *link;
126 const char *name;
127 } root_table;
128
129 struct unwind_item {
130 enum item_location {
131 Nowhere,
132 Memory,
133 Register,
134 Value
135 } where;
136 uleb128_t value;
137 };
138
139 struct unwind_state {
140 uleb128_t loc, org;
141 const u8 *cieStart, *cieEnd;
142 uleb128_t codeAlign;
143 sleb128_t dataAlign;
144 struct cfa {
145 uleb128_t reg, offs;
146 } cfa;
147 struct unwind_item regs[ARRAY_SIZE(reg_info)];
148 unsigned stackDepth:8;
149 unsigned version:8;
150 const u8 *label;
151 const u8 *stack[MAX_STACK_DEPTH];
152 };
153
154 static const struct cfa badCFA = { ARRAY_SIZE(reg_info), 1 };
155
156 static struct unwind_table *find_table(unsigned long pc)
157 {
158 struct unwind_table *table;
159
160 for (table = &root_table; table; table = table->link)
161 if ((pc >= table->core.pc
162 && pc < table->core.pc + table->core.range)
163 || (pc >= table->init.pc
164 && pc < table->init.pc + table->init.range))
165 break;
166
167 return table;
168 }
169
170 static unsigned long read_pointer(const u8 **pLoc,
171 const void *end, signed ptrType);
172 static void init_unwind_hdr(struct unwind_table *table,
173 void *(*alloc) (unsigned long));
174
175 /*
176 * wrappers for header alloc (vs. calling one vs. other at call site)
177 * to elide section mismatches warnings
178 */
179 static void *__init unw_hdr_alloc_early(unsigned long sz)
180 {
181 return memblock_alloc_from(sz, sizeof(unsigned int), MAX_DMA_ADDRESS);
182 }
183
184 static void *unw_hdr_alloc(unsigned long sz)
185 {
186 return kmalloc(sz, GFP_KERNEL);
187 }
188
189 static void init_unwind_table(struct unwind_table *table, const char *name,
190 const void *core_start, unsigned long core_size,
191 const void *init_start, unsigned long init_size,
192 const void *table_start, unsigned long table_size,
193 const u8 *header_start, unsigned long header_size)
194 {
195 const u8 *ptr = header_start + 4;
196 const u8 *end = header_start + header_size;
197
198 table->core.pc = (unsigned long)core_start;
199 table->core.range = core_size;
200 table->init.pc = (unsigned long)init_start;
201 table->init.range = init_size;
202 table->address = table_start;
203 table->size = table_size;
204
205 /* See if the linker provided table looks valid. */
206 if (header_size <= 4
207 || header_start[0] != 1
208 || (void *)read_pointer(&ptr, end, header_start[1]) != table_start
209 || header_start[2] == DW_EH_PE_omit
210 || read_pointer(&ptr, end, header_start[2]) <= 0
211 || header_start[3] == DW_EH_PE_omit)
212 header_start = NULL;
213
214 table->hdrsz = header_size;
215 smp_wmb();
216 table->header = header_start;
217 table->link = NULL;
218 table->name = name;
219 }
220
221 void __init arc_unwind_init(void)
222 {
223 init_unwind_table(&root_table, "kernel", _text, _end - _text, NULL, 0,
224 __start_unwind, __end_unwind - __start_unwind,
225 NULL, 0);
226 /*__start_unwind_hdr, __end_unwind_hdr - __start_unwind_hdr);*/
227
228 init_unwind_hdr(&root_table, unw_hdr_alloc_early);
229 }
230
231 static const u32 bad_cie, not_fde;
232 static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *);
233 static const u32 *__cie_for_fde(const u32 *fde);
234 static signed fde_pointer_type(const u32 *cie);
235
236 struct eh_frame_hdr_table_entry {
237 unsigned long start, fde;
238 };
239
240 static int cmp_eh_frame_hdr_table_entries(const void *p1, const void *p2)
241 {
242 const struct eh_frame_hdr_table_entry *e1 = p1;
243 const struct eh_frame_hdr_table_entry *e2 = p2;
244
245 return (e1->start > e2->start) - (e1->start < e2->start);
246 }
247
248 static void swap_eh_frame_hdr_table_entries(void *p1, void *p2, int size)
249 {
250 struct eh_frame_hdr_table_entry *e1 = p1;
251 struct eh_frame_hdr_table_entry *e2 = p2;
252 unsigned long v;
253
254 v = e1->start;
255 e1->start = e2->start;
256 e2->start = v;
257 v = e1->fde;
258 e1->fde = e2->fde;
259 e2->fde = v;
260 }
261
262 static void init_unwind_hdr(struct unwind_table *table,
263 void *(*alloc) (unsigned long))
264 {
265 const u8 *ptr;
266 unsigned long tableSize = table->size, hdrSize;
267 unsigned n;
268 const u32 *fde;
269 struct {
270 u8 version;
271 u8 eh_frame_ptr_enc;
272 u8 fde_count_enc;
273 u8 table_enc;
274 unsigned long eh_frame_ptr;
275 unsigned int fde_count;
276 struct eh_frame_hdr_table_entry table[];
277 } __attribute__ ((__packed__)) *header;
278
279 if (table->header)
280 return;
281
282 if (table->hdrsz)
283 pr_warn(".eh_frame_hdr for '%s' present but unusable\n",
284 table->name);
285
286 if (tableSize & (sizeof(*fde) - 1))
287 return;
288
289 for (fde = table->address, n = 0;
290 tableSize > sizeof(*fde) && tableSize - sizeof(*fde) >= *fde;
291 tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) {
292 const u32 *cie = cie_for_fde(fde, table);
293 signed ptrType;
294
295 if (cie == &not_fde)
296 continue;
297 if (cie == NULL || cie == &bad_cie)
298 goto ret_err;
299 ptrType = fde_pointer_type(cie);
300 if (ptrType < 0)
301 goto ret_err;
302
303 ptr = (const u8 *)(fde + 2);
304 if (!read_pointer(&ptr, (const u8 *)(fde + 1) + *fde,
305 ptrType)) {
306 /* FIXME_Rajesh We have 4 instances of null addresses
307 * instead of the initial loc addr
308 * return;
309 */
310 WARN(1, "unwinder: FDE->initial_location NULL %p\n",
311 (const u8 *)(fde + 1) + *fde);
312 }
313 ++n;
314 }
315
316 if (tableSize || !n)
317 goto ret_err;
318
319 hdrSize = 4 + sizeof(unsigned long) + sizeof(unsigned int)
320 + 2 * n * sizeof(unsigned long);
321
322 header = alloc(hdrSize);
323 if (!header)
324 goto ret_err;
325
326 header->version = 1;
327 header->eh_frame_ptr_enc = DW_EH_PE_abs | DW_EH_PE_native;
328 header->fde_count_enc = DW_EH_PE_abs | DW_EH_PE_data4;
329 header->table_enc = DW_EH_PE_abs | DW_EH_PE_native;
330 put_unaligned((unsigned long)table->address, &header->eh_frame_ptr);
331 BUILD_BUG_ON(offsetof(typeof(*header), fde_count)
332 % __alignof(typeof(header->fde_count)));
333 header->fde_count = n;
334
335 BUILD_BUG_ON(offsetof(typeof(*header), table)
336 % __alignof(typeof(*header->table)));
337 for (fde = table->address, tableSize = table->size, n = 0;
338 tableSize;
339 tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) {
340 const u32 *cie = __cie_for_fde(fde);
341
342 if (fde[1] == CIE_ID)
343 continue; /* this is a CIE */
344 ptr = (const u8 *)(fde + 2);
345 header->table[n].start = read_pointer(&ptr,
346 (const u8 *)(fde + 1) +
347 *fde,
348 fde_pointer_type(cie));
349 header->table[n].fde = (unsigned long)fde;
350 ++n;
351 }
352 WARN_ON(n != header->fde_count);
353
354 sort(header->table,
355 n,
356 sizeof(*header->table),
357 cmp_eh_frame_hdr_table_entries, swap_eh_frame_hdr_table_entries);
358
359 table->hdrsz = hdrSize;
360 smp_wmb();
361 table->header = (const void *)header;
362 return;
363
364 ret_err:
365 panic("Attention !!! Dwarf FDE parsing errors\n");
366 }
367
368 #ifdef CONFIG_MODULES
369
370 static struct unwind_table *last_table;
371
372 /* Must be called with module_mutex held. */
373 void *unwind_add_table(struct module *module, const void *table_start,
374 unsigned long table_size)
375 {
376 struct unwind_table *table;
377
378 if (table_size <= 0)
379 return NULL;
380
381 table = kmalloc(sizeof(*table), GFP_KERNEL);
382 if (!table)
383 return NULL;
384
385 init_unwind_table(table, module->name,
386 module->core_layout.base, module->core_layout.size,
387 module->init_layout.base, module->init_layout.size,
388 table_start, table_size,
389 NULL, 0);
390
391 init_unwind_hdr(table, unw_hdr_alloc);
392
393 #ifdef UNWIND_DEBUG
394 unw_debug("Table added for [%s] %lx %lx\n",
395 module->name, table->core.pc, table->core.range);
396 #endif
397 if (last_table)
398 last_table->link = table;
399 else
400 root_table.link = table;
401 last_table = table;
402
403 return table;
404 }
405
406 struct unlink_table_info {
407 struct unwind_table *table;
408 int init_only;
409 };
410
411 static int unlink_table(void *arg)
412 {
413 struct unlink_table_info *info = arg;
414 struct unwind_table *table = info->table, *prev;
415
416 for (prev = &root_table; prev->link && prev->link != table;
417 prev = prev->link)
418 ;
419
420 if (prev->link) {
421 if (info->init_only) {
422 table->init.pc = 0;
423 table->init.range = 0;
424 info->table = NULL;
425 } else {
426 prev->link = table->link;
427 if (!prev->link)
428 last_table = prev;
429 }
430 } else
431 info->table = NULL;
432
433 return 0;
434 }
435
436 /* Must be called with module_mutex held. */
437 void unwind_remove_table(void *handle, int init_only)
438 {
439 struct unwind_table *table = handle;
440 struct unlink_table_info info;
441
442 if (!table || table == &root_table)
443 return;
444
445 if (init_only && table == last_table) {
446 table->init.pc = 0;
447 table->init.range = 0;
448 return;
449 }
450
451 info.table = table;
452 info.init_only = init_only;
453
454 unlink_table(&info); /* XXX: SMP */
455 kfree(table->header);
456 kfree(table);
457 }
458
459 #endif /* CONFIG_MODULES */
460
461 static uleb128_t get_uleb128(const u8 **pcur, const u8 *end)
462 {
463 const u8 *cur = *pcur;
464 uleb128_t value;
465 unsigned shift;
466
467 for (shift = 0, value = 0; cur < end; shift += 7) {
468 if (shift + 7 > 8 * sizeof(value)
469 && (*cur & 0x7fU) >= (1U << (8 * sizeof(value) - shift))) {
470 cur = end + 1;
471 break;
472 }
473 value |= (uleb128_t) (*cur & 0x7f) << shift;
474 if (!(*cur++ & 0x80))
475 break;
476 }
477 *pcur = cur;
478
479 return value;
480 }
481
482 static sleb128_t get_sleb128(const u8 **pcur, const u8 *end)
483 {
484 const u8 *cur = *pcur;
485 sleb128_t value;
486 unsigned shift;
487
488 for (shift = 0, value = 0; cur < end; shift += 7) {
489 if (shift + 7 > 8 * sizeof(value)
490 && (*cur & 0x7fU) >= (1U << (8 * sizeof(value) - shift))) {
491 cur = end + 1;
492 break;
493 }
494 value |= (sleb128_t) (*cur & 0x7f) << shift;
495 if (!(*cur & 0x80)) {
496 value |= -(*cur++ & 0x40) << shift;
497 break;
498 }
499 }
500 *pcur = cur;
501
502 return value;
503 }
504
505 static const u32 *__cie_for_fde(const u32 *fde)
506 {
507 const u32 *cie;
508
509 cie = fde + 1 - fde[1] / sizeof(*fde);
510
511 return cie;
512 }
513
514 static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *table)
515 {
516 const u32 *cie;
517
518 if (!*fde || (*fde & (sizeof(*fde) - 1)))
519 return &bad_cie;
520
521 if (fde[1] == CIE_ID)
522 return &not_fde; /* this is a CIE */
523
524 if ((fde[1] & (sizeof(*fde) - 1)))
525 /* || fde[1] > (unsigned long)(fde + 1) - (unsigned long)table->address) */
526 return NULL; /* this is not a valid FDE */
527
528 cie = __cie_for_fde(fde);
529
530 if (*cie <= sizeof(*cie) + 4 || *cie >= fde[1] - sizeof(*fde)
531 || (*cie & (sizeof(*cie) - 1))
532 || (cie[1] != CIE_ID))
533 return NULL; /* this is not a (valid) CIE */
534 return cie;
535 }
536
537 static unsigned long read_pointer(const u8 **pLoc, const void *end,
538 signed ptrType)
539 {
540 unsigned long value = 0;
541 union {
542 const u8 *p8;
543 const u16 *p16u;
544 const s16 *p16s;
545 const u32 *p32u;
546 const s32 *p32s;
547 const unsigned long *pul;
548 } ptr;
549
550 if (ptrType < 0 || ptrType == DW_EH_PE_omit)
551 return 0;
552 ptr.p8 = *pLoc;
553 switch (ptrType & DW_EH_PE_FORM) {
554 case DW_EH_PE_data2:
555 if (end < (const void *)(ptr.p16u + 1))
556 return 0;
557 if (ptrType & DW_EH_PE_signed)
558 value = get_unaligned((u16 *) ptr.p16s++);
559 else
560 value = get_unaligned((u16 *) ptr.p16u++);
561 break;
562 case DW_EH_PE_data4:
563 #ifdef CONFIG_64BIT
564 if (end < (const void *)(ptr.p32u + 1))
565 return 0;
566 if (ptrType & DW_EH_PE_signed)
567 value = get_unaligned(ptr.p32s++);
568 else
569 value = get_unaligned(ptr.p32u++);
570 break;
571 case DW_EH_PE_data8:
572 BUILD_BUG_ON(sizeof(u64) != sizeof(value));
573 #else
574 BUILD_BUG_ON(sizeof(u32) != sizeof(value));
575 #endif
576 case DW_EH_PE_native:
577 if (end < (const void *)(ptr.pul + 1))
578 return 0;
579 value = get_unaligned((unsigned long *)ptr.pul++);
580 break;
581 case DW_EH_PE_leb128:
582 BUILD_BUG_ON(sizeof(uleb128_t) > sizeof(value));
583 value = ptrType & DW_EH_PE_signed ? get_sleb128(&ptr.p8, end)
584 : get_uleb128(&ptr.p8, end);
585 if ((const void *)ptr.p8 > end)
586 return 0;
587 break;
588 default:
589 return 0;
590 }
591 switch (ptrType & DW_EH_PE_ADJUST) {
592 case DW_EH_PE_abs:
593 break;
594 case DW_EH_PE_pcrel:
595 value += (unsigned long)*pLoc;
596 break;
597 default:
598 return 0;
599 }
600 if ((ptrType & DW_EH_PE_indirect)
601 && __get_user(value, (unsigned long __user *)value))
602 return 0;
603 *pLoc = ptr.p8;
604
605 return value;
606 }
607
608 static signed fde_pointer_type(const u32 *cie)
609 {
610 const u8 *ptr = (const u8 *)(cie + 2);
611 unsigned version = *ptr;
612
613 if (*++ptr) {
614 const char *aug;
615 const u8 *end = (const u8 *)(cie + 1) + *cie;
616 uleb128_t len;
617
618 /* check if augmentation size is first (and thus present) */
619 if (*ptr != 'z')
620 return -1;
621
622 /* check if augmentation string is nul-terminated */
623 aug = (const void *)ptr;
624 ptr = memchr(aug, 0, end - ptr);
625 if (ptr == NULL)
626 return -1;
627
628 ++ptr; /* skip terminator */
629 get_uleb128(&ptr, end); /* skip code alignment */
630 get_sleb128(&ptr, end); /* skip data alignment */
631 /* skip return address column */
632 version <= 1 ? (void) ++ptr : (void)get_uleb128(&ptr, end);
633 len = get_uleb128(&ptr, end); /* augmentation length */
634
635 if (ptr + len < ptr || ptr + len > end)
636 return -1;
637
638 end = ptr + len;
639 while (*++aug) {
640 if (ptr >= end)
641 return -1;
642 switch (*aug) {
643 case 'L':
644 ++ptr;
645 break;
646 case 'P':{
647 signed ptrType = *ptr++;
648
649 if (!read_pointer(&ptr, end, ptrType)
650 || ptr > end)
651 return -1;
652 }
653 break;
654 case 'R':
655 return *ptr;
656 default:
657 return -1;
658 }
659 }
660 }
661 return DW_EH_PE_native | DW_EH_PE_abs;
662 }
663
664 static int advance_loc(unsigned long delta, struct unwind_state *state)
665 {
666 state->loc += delta * state->codeAlign;
667
668 /* FIXME_Rajesh: Probably we are defining for the initial range as well;
669 return delta > 0;
670 */
671 unw_debug("delta %3lu => loc 0x%lx: ", delta, state->loc);
672 return 1;
673 }
674
675 static void set_rule(uleb128_t reg, enum item_location where, uleb128_t value,
676 struct unwind_state *state)
677 {
678 if (reg < ARRAY_SIZE(state->regs)) {
679 state->regs[reg].where = where;
680 state->regs[reg].value = value;
681
682 #ifdef UNWIND_DEBUG
683 unw_debug("r%lu: ", reg);
684 switch (where) {
685 case Nowhere:
686 unw_debug("s ");
687 break;
688 case Memory:
689 unw_debug("c(%lu) ", value);
690 break;
691 case Register:
692 unw_debug("r(%lu) ", value);
693 break;
694 case Value:
695 unw_debug("v(%lu) ", value);
696 break;
697 default:
698 break;
699 }
700 #endif
701 }
702 }
703
704 static int processCFI(const u8 *start, const u8 *end, unsigned long targetLoc,
705 signed ptrType, struct unwind_state *state)
706 {
707 union {
708 const u8 *p8;
709 const u16 *p16;
710 const u32 *p32;
711 } ptr;
712 int result = 1;
713 u8 opcode;
714
715 if (start != state->cieStart) {
716 state->loc = state->org;
717 result =
718 processCFI(state->cieStart, state->cieEnd, 0, ptrType,
719 state);
720 if (targetLoc == 0 && state->label == NULL)
721 return result;
722 }
723 for (ptr.p8 = start; result && ptr.p8 < end;) {
724 switch (*ptr.p8 >> 6) {
725 uleb128_t value;
726
727 case 0:
728 opcode = *ptr.p8++;
729
730 switch (opcode) {
731 case DW_CFA_nop:
732 unw_debug("cfa nop ");
733 break;
734 case DW_CFA_set_loc:
735 state->loc = read_pointer(&ptr.p8, end,
736 ptrType);
737 if (state->loc == 0)
738 result = 0;
739 unw_debug("cfa_set_loc: 0x%lx ", state->loc);
740 break;
741 case DW_CFA_advance_loc1:
742 unw_debug("\ncfa advance loc1:");
743 result = ptr.p8 < end
744 && advance_loc(*ptr.p8++, state);
745 break;
746 case DW_CFA_advance_loc2:
747 value = *ptr.p8++;
748 value += *ptr.p8++ << 8;
749 unw_debug("\ncfa advance loc2:");
750 result = ptr.p8 <= end + 2
751 /* && advance_loc(*ptr.p16++, state); */
752 && advance_loc(value, state);
753 break;
754 case DW_CFA_advance_loc4:
755 unw_debug("\ncfa advance loc4:");
756 result = ptr.p8 <= end + 4
757 && advance_loc(*ptr.p32++, state);
758 break;
759 case DW_CFA_offset_extended:
760 value = get_uleb128(&ptr.p8, end);
761 unw_debug("cfa_offset_extended: ");
762 set_rule(value, Memory,
763 get_uleb128(&ptr.p8, end), state);
764 break;
765 case DW_CFA_val_offset:
766 value = get_uleb128(&ptr.p8, end);
767 set_rule(value, Value,
768 get_uleb128(&ptr.p8, end), state);
769 break;
770 case DW_CFA_offset_extended_sf:
771 value = get_uleb128(&ptr.p8, end);
772 set_rule(value, Memory,
773 get_sleb128(&ptr.p8, end), state);
774 break;
775 case DW_CFA_val_offset_sf:
776 value = get_uleb128(&ptr.p8, end);
777 set_rule(value, Value,
778 get_sleb128(&ptr.p8, end), state);
779 break;
780 case DW_CFA_restore_extended:
781 unw_debug("cfa_restore_extended: ");
782 case DW_CFA_undefined:
783 unw_debug("cfa_undefined: ");
784 case DW_CFA_same_value:
785 unw_debug("cfa_same_value: ");
786 set_rule(get_uleb128(&ptr.p8, end), Nowhere, 0,
787 state);
788 break;
789 case DW_CFA_register:
790 unw_debug("cfa_register: ");
791 value = get_uleb128(&ptr.p8, end);
792 set_rule(value,
793 Register,
794 get_uleb128(&ptr.p8, end), state);
795 break;
796 case DW_CFA_remember_state:
797 unw_debug("cfa_remember_state: ");
798 if (ptr.p8 == state->label) {
799 state->label = NULL;
800 return 1;
801 }
802 if (state->stackDepth >= MAX_STACK_DEPTH)
803 return 0;
804 state->stack[state->stackDepth++] = ptr.p8;
805 break;
806 case DW_CFA_restore_state:
807 unw_debug("cfa_restore_state: ");
808 if (state->stackDepth) {
809 const uleb128_t loc = state->loc;
810 const u8 *label = state->label;
811
812 state->label =
813 state->stack[state->stackDepth - 1];
814 memcpy(&state->cfa, &badCFA,
815 sizeof(state->cfa));
816 memset(state->regs, 0,
817 sizeof(state->regs));
818 state->stackDepth = 0;
819 result =
820 processCFI(start, end, 0, ptrType,
821 state);
822 state->loc = loc;
823 state->label = label;
824 } else
825 return 0;
826 break;
827 case DW_CFA_def_cfa:
828 state->cfa.reg = get_uleb128(&ptr.p8, end);
829 unw_debug("cfa_def_cfa: r%lu ", state->cfa.reg);
830 /*nobreak*/
831 case DW_CFA_def_cfa_offset:
832 state->cfa.offs = get_uleb128(&ptr.p8, end);
833 unw_debug("cfa_def_cfa_offset: 0x%lx ",
834 state->cfa.offs);
835 break;
836 case DW_CFA_def_cfa_sf:
837 state->cfa.reg = get_uleb128(&ptr.p8, end);
838 /*nobreak */
839 case DW_CFA_def_cfa_offset_sf:
840 state->cfa.offs = get_sleb128(&ptr.p8, end)
841 * state->dataAlign;
842 break;
843 case DW_CFA_def_cfa_register:
844 unw_debug("cfa_def_cfa_register: ");
845 state->cfa.reg = get_uleb128(&ptr.p8, end);
846 break;
847 /*todo case DW_CFA_def_cfa_expression: */
848 /*todo case DW_CFA_expression: */
849 /*todo case DW_CFA_val_expression: */
850 case DW_CFA_GNU_args_size:
851 get_uleb128(&ptr.p8, end);
852 break;
853 case DW_CFA_GNU_negative_offset_extended:
854 value = get_uleb128(&ptr.p8, end);
855 set_rule(value,
856 Memory,
857 (uleb128_t) 0 - get_uleb128(&ptr.p8,
858 end),
859 state);
860 break;
861 case DW_CFA_GNU_window_save:
862 default:
863 unw_debug("UNKNOWN OPCODE 0x%x\n", opcode);
864 result = 0;
865 break;
866 }
867 break;
868 case 1:
869 unw_debug("\ncfa_adv_loc: ");
870 result = advance_loc(*ptr.p8++ & 0x3f, state);
871 break;
872 case 2:
873 unw_debug("cfa_offset: ");
874 value = *ptr.p8++ & 0x3f;
875 set_rule(value, Memory, get_uleb128(&ptr.p8, end),
876 state);
877 break;
878 case 3:
879 unw_debug("cfa_restore: ");
880 set_rule(*ptr.p8++ & 0x3f, Nowhere, 0, state);
881 break;
882 }
883
884 if (ptr.p8 > end)
885 result = 0;
886 if (result && targetLoc != 0 && targetLoc < state->loc)
887 return 1;
888 }
889
890 return result && ptr.p8 == end && (targetLoc == 0 || (
891 /*todo While in theory this should apply, gcc in practice omits
892 everything past the function prolog, and hence the location
893 never reaches the end of the function.
894 targetLoc < state->loc && */ state->label == NULL));
895 }
896
897 /* Unwind to previous to frame. Returns 0 if successful, negative
898 * number in case of an error. */
899 int arc_unwind(struct unwind_frame_info *frame)
900 {
901 #define FRAME_REG(r, t) (((t *)frame)[reg_info[r].offs])
902 const u32 *fde = NULL, *cie = NULL;
903 const u8 *ptr = NULL, *end = NULL;
904 unsigned long pc = UNW_PC(frame) - frame->call_frame;
905 unsigned long startLoc = 0, endLoc = 0, cfa;
906 unsigned i;
907 signed ptrType = -1;
908 uleb128_t retAddrReg = 0;
909 const struct unwind_table *table;
910 struct unwind_state state;
911 unsigned long *fptr;
912 unsigned long addr;
913
914 unw_debug("\n\nUNWIND FRAME:\n");
915 unw_debug("PC: 0x%lx BLINK: 0x%lx, SP: 0x%lx, FP: 0x%x\n",
916 UNW_PC(frame), UNW_BLINK(frame), UNW_SP(frame),
917 UNW_FP(frame));
918
919 if (UNW_PC(frame) == 0)
920 return -EINVAL;
921
922 #ifdef UNWIND_DEBUG
923 {
924 unsigned long *sptr = (unsigned long *)UNW_SP(frame);
925 unw_debug("\nStack Dump:\n");
926 for (i = 0; i < 20; i++, sptr++)
927 unw_debug("0x%p: 0x%lx\n", sptr, *sptr);
928 unw_debug("\n");
929 }
930 #endif
931
932 table = find_table(pc);
933 if (table != NULL
934 && !(table->size & (sizeof(*fde) - 1))) {
935 const u8 *hdr = table->header;
936 unsigned long tableSize;
937
938 smp_rmb();
939 if (hdr && hdr[0] == 1) {
940 switch (hdr[3] & DW_EH_PE_FORM) {
941 case DW_EH_PE_native:
942 tableSize = sizeof(unsigned long);
943 break;
944 case DW_EH_PE_data2:
945 tableSize = 2;
946 break;
947 case DW_EH_PE_data4:
948 tableSize = 4;
949 break;
950 case DW_EH_PE_data8:
951 tableSize = 8;
952 break;
953 default:
954 tableSize = 0;
955 break;
956 }
957 ptr = hdr + 4;
958 end = hdr + table->hdrsz;
959 if (tableSize && read_pointer(&ptr, end, hdr[1])
960 == (unsigned long)table->address
961 && (i = read_pointer(&ptr, end, hdr[2])) > 0
962 && i == (end - ptr) / (2 * tableSize)
963 && !((end - ptr) % (2 * tableSize))) {
964 do {
965 const u8 *cur =
966 ptr + (i / 2) * (2 * tableSize);
967
968 startLoc = read_pointer(&cur,
969 cur + tableSize,
970 hdr[3]);
971 if (pc < startLoc)
972 i /= 2;
973 else {
974 ptr = cur - tableSize;
975 i = (i + 1) / 2;
976 }
977 } while (startLoc && i > 1);
978 if (i == 1
979 && (startLoc = read_pointer(&ptr,
980 ptr + tableSize,
981 hdr[3])) != 0
982 && pc >= startLoc)
983 fde = (void *)read_pointer(&ptr,
984 ptr +
985 tableSize,
986 hdr[3]);
987 }
988 }
989
990 if (fde != NULL) {
991 cie = cie_for_fde(fde, table);
992 ptr = (const u8 *)(fde + 2);
993 if (cie != NULL
994 && cie != &bad_cie
995 && cie != &not_fde
996 && (ptrType = fde_pointer_type(cie)) >= 0
997 && read_pointer(&ptr,
998 (const u8 *)(fde + 1) + *fde,
999 ptrType) == startLoc) {
1000 if (!(ptrType & DW_EH_PE_indirect))
1001 ptrType &=
1002 DW_EH_PE_FORM | DW_EH_PE_signed;
1003 endLoc =
1004 startLoc + read_pointer(&ptr,
1005 (const u8 *)(fde +
1006 1) +
1007 *fde, ptrType);
1008 if (pc >= endLoc) {
1009 fde = NULL;
1010 cie = NULL;
1011 }
1012 } else {
1013 fde = NULL;
1014 cie = NULL;
1015 }
1016 }
1017 }
1018 if (cie != NULL) {
1019 memset(&state, 0, sizeof(state));
1020 state.cieEnd = ptr; /* keep here temporarily */
1021 ptr = (const u8 *)(cie + 2);
1022 end = (const u8 *)(cie + 1) + *cie;
1023 frame->call_frame = 1;
1024 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 alignment factor */
1051 state.codeAlign = get_uleb128(&ptr, end);
1052 /* get data alignment 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);
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