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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
28extern 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
34int dbg_unw;
35#define unw_debug(fmt, ...) \
36do { \
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
55static const struct {
56 unsigned offs:BITS_PER_LONG / 2;
57 unsigned width:BITS_PER_LONG / 2;
58} reg_info[] = {
59UNW_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#define CIE_ID 0
115
116typedef unsigned long uleb128_t;
117typedef signed long sleb128_t;
118
119static struct unwind_table {
120 struct {
121 unsigned long pc;
122 unsigned long range;
123 } core, init;
124 const void *address;
125 unsigned long size;
126 const unsigned char *header;
127 unsigned long hdrsz;
128 struct unwind_table *link;
129 const char *name;
130} root_table;
131
132struct unwind_item {
133 enum item_location {
134 Nowhere,
135 Memory,
136 Register,
137 Value
138 } where;
139 uleb128_t value;
140};
141
142struct unwind_state {
143 uleb128_t loc, org;
144 const u8 *cieStart, *cieEnd;
145 uleb128_t codeAlign;
146 sleb128_t dataAlign;
147 struct cfa {
148 uleb128_t reg, offs;
149 } cfa;
150 struct unwind_item regs[ARRAY_SIZE(reg_info)];
151 unsigned stackDepth:8;
152 unsigned version:8;
153 const u8 *label;
154 const u8 *stack[MAX_STACK_DEPTH];
155};
156
157static const struct cfa badCFA = { ARRAY_SIZE(reg_info), 1 };
158
159static struct unwind_table *find_table(unsigned long pc)
160{
161 struct unwind_table *table;
162
163 for (table = &root_table; table; table = table->link)
164 if ((pc >= table->core.pc
165 && pc < table->core.pc + table->core.range)
166 || (pc >= table->init.pc
167 && pc < table->init.pc + table->init.range))
168 break;
169
170 return table;
171}
172
173static unsigned long read_pointer(const u8 **pLoc,
174 const void *end, signed ptrType);
175static void init_unwind_hdr(struct unwind_table *table,
176 void *(*alloc) (unsigned long));
177
178/*
179 * wrappers for header alloc (vs. calling one vs. other at call site)
180 * to elide section mismatches warnings
181 */
182static void *__init unw_hdr_alloc_early(unsigned long sz)
183{
184 return __alloc_bootmem_nopanic(sz, sizeof(unsigned int),
185 MAX_DMA_ADDRESS);
186}
187
188static void *unw_hdr_alloc(unsigned long sz)
189{
190 return kmalloc(sz, GFP_KERNEL);
191}
192
193static void init_unwind_table(struct unwind_table *table, const char *name,
194 const void *core_start, unsigned long core_size,
195 const void *init_start, unsigned long init_size,
196 const void *table_start, unsigned long table_size,
197 const u8 *header_start, unsigned long header_size)
198{
199 const u8 *ptr = header_start + 4;
200 const u8 *end = header_start + header_size;
201
202 table->core.pc = (unsigned long)core_start;
203 table->core.range = core_size;
204 table->init.pc = (unsigned long)init_start;
205 table->init.range = init_size;
206 table->address = table_start;
207 table->size = table_size;
208
209 /* See if the linker provided table looks valid. */
210 if (header_size <= 4
211 || header_start[0] != 1
212 || (void *)read_pointer(&ptr, end, header_start[1]) != table_start
213 || header_start[2] == DW_EH_PE_omit
214 || read_pointer(&ptr, end, header_start[2]) <= 0
215 || header_start[3] == DW_EH_PE_omit)
216 header_start = NULL;
217
218 table->hdrsz = header_size;
219 smp_wmb();
220 table->header = header_start;
221 table->link = NULL;
222 table->name = name;
223}
224
225void __init arc_unwind_init(void)
226{
227 init_unwind_table(&root_table, "kernel", _text, _end - _text, NULL, 0,
228 __start_unwind, __end_unwind - __start_unwind,
229 NULL, 0);
230 /*__start_unwind_hdr, __end_unwind_hdr - __start_unwind_hdr);*/
231
232 init_unwind_hdr(&root_table, unw_hdr_alloc_early);
233}
234
235static const u32 bad_cie, not_fde;
236static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *);
237static const u32 *__cie_for_fde(const u32 *fde);
238static signed fde_pointer_type(const u32 *cie);
239
240struct eh_frame_hdr_table_entry {
241 unsigned long start, fde;
242};
243
244static int cmp_eh_frame_hdr_table_entries(const void *p1, const void *p2)
245{
246 const struct eh_frame_hdr_table_entry *e1 = p1;
247 const struct eh_frame_hdr_table_entry *e2 = p2;
248
249 return (e1->start > e2->start) - (e1->start < e2->start);
250}
251
252static void swap_eh_frame_hdr_table_entries(void *p1, void *p2, int size)
253{
254 struct eh_frame_hdr_table_entry *e1 = p1;
255 struct eh_frame_hdr_table_entry *e2 = p2;
256 unsigned long v;
257
258 v = e1->start;
259 e1->start = e2->start;
260 e2->start = v;
261 v = e1->fde;
262 e1->fde = e2->fde;
263 e2->fde = v;
264}
265
266static void init_unwind_hdr(struct unwind_table *table,
267 void *(*alloc) (unsigned long))
268{
269 const u8 *ptr;
270 unsigned long tableSize = table->size, hdrSize;
271 unsigned n;
272 const u32 *fde;
273 struct {
274 u8 version;
275 u8 eh_frame_ptr_enc;
276 u8 fde_count_enc;
277 u8 table_enc;
278 unsigned long eh_frame_ptr;
279 unsigned int fde_count;
280 struct eh_frame_hdr_table_entry table[];
281 } __attribute__ ((__packed__)) *header;
282
283 if (table->header)
284 return;
285
286 if (table->hdrsz)
287 pr_warn(".eh_frame_hdr for '%s' present but unusable\n",
288 table->name);
289
290 if (tableSize & (sizeof(*fde) - 1))
291 return;
292
293 for (fde = table->address, n = 0;
294 tableSize > sizeof(*fde) && tableSize - sizeof(*fde) >= *fde;
295 tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) {
296 const u32 *cie = cie_for_fde(fde, table);
297 signed ptrType;
298
299 if (cie == ¬_fde)
300 continue;
301 if (cie == NULL || cie == &bad_cie)
302 goto ret_err;
303 ptrType = fde_pointer_type(cie);
304 if (ptrType < 0)
305 goto ret_err;
306
307 ptr = (const u8 *)(fde + 2);
308 if (!read_pointer(&ptr, (const u8 *)(fde + 1) + *fde,
309 ptrType)) {
310 /* FIXME_Rajesh We have 4 instances of null addresses
311 * instead of the initial loc addr
312 * return;
313 */
314 WARN(1, "unwinder: FDE->initial_location NULL %p\n",
315 (const u8 *)(fde + 1) + *fde);
316 }
317 ++n;
318 }
319
320 if (tableSize || !n)
321 goto ret_err;
322
323 hdrSize = 4 + sizeof(unsigned long) + sizeof(unsigned int)
324 + 2 * n * sizeof(unsigned long);
325
326 header = alloc(hdrSize);
327 if (!header)
328 goto ret_err;
329
330 header->version = 1;
331 header->eh_frame_ptr_enc = DW_EH_PE_abs | DW_EH_PE_native;
332 header->fde_count_enc = DW_EH_PE_abs | DW_EH_PE_data4;
333 header->table_enc = DW_EH_PE_abs | DW_EH_PE_native;
334 put_unaligned((unsigned long)table->address, &header->eh_frame_ptr);
335 BUILD_BUG_ON(offsetof(typeof(*header), fde_count)
336 % __alignof(typeof(header->fde_count)));
337 header->fde_count = n;
338
339 BUILD_BUG_ON(offsetof(typeof(*header), table)
340 % __alignof(typeof(*header->table)));
341 for (fde = table->address, tableSize = table->size, n = 0;
342 tableSize;
343 tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) {
344 const u32 *cie = __cie_for_fde(fde);
345
346 if (fde[1] == CIE_ID)
347 continue; /* this is a CIE */
348 ptr = (const u8 *)(fde + 2);
349 header->table[n].start = read_pointer(&ptr,
350 (const u8 *)(fde + 1) +
351 *fde,
352 fde_pointer_type(cie));
353 header->table[n].fde = (unsigned long)fde;
354 ++n;
355 }
356 WARN_ON(n != header->fde_count);
357
358 sort(header->table,
359 n,
360 sizeof(*header->table),
361 cmp_eh_frame_hdr_table_entries, swap_eh_frame_hdr_table_entries);
362
363 table->hdrsz = hdrSize;
364 smp_wmb();
365 table->header = (const void *)header;
366 return;
367
368ret_err:
369 panic("Attention !!! Dwarf FDE parsing errors\n");;
370}
371
372#ifdef CONFIG_MODULES
373
374static struct unwind_table *last_table;
375
376/* Must be called with module_mutex held. */
377void *unwind_add_table(struct module *module, const void *table_start,
378 unsigned long table_size)
379{
380 struct unwind_table *table;
381
382 if (table_size <= 0)
383 return NULL;
384
385 table = kmalloc(sizeof(*table), GFP_KERNEL);
386 if (!table)
387 return NULL;
388
389 init_unwind_table(table, module->name,
390 module->core_layout.base, module->core_layout.size,
391 module->init_layout.base, module->init_layout.size,
392 table_start, table_size,
393 NULL, 0);
394
395 init_unwind_hdr(table, unw_hdr_alloc);
396
397#ifdef UNWIND_DEBUG
398 unw_debug("Table added for [%s] %lx %lx\n",
399 module->name, table->core.pc, table->core.range);
400#endif
401 if (last_table)
402 last_table->link = table;
403 else
404 root_table.link = table;
405 last_table = table;
406
407 return table;
408}
409
410struct unlink_table_info {
411 struct unwind_table *table;
412 int init_only;
413};
414
415static int unlink_table(void *arg)
416{
417 struct unlink_table_info *info = arg;
418 struct unwind_table *table = info->table, *prev;
419
420 for (prev = &root_table; prev->link && prev->link != table;
421 prev = prev->link)
422 ;
423
424 if (prev->link) {
425 if (info->init_only) {
426 table->init.pc = 0;
427 table->init.range = 0;
428 info->table = NULL;
429 } else {
430 prev->link = table->link;
431 if (!prev->link)
432 last_table = prev;
433 }
434 } else
435 info->table = NULL;
436
437 return 0;
438}
439
440/* Must be called with module_mutex held. */
441void unwind_remove_table(void *handle, int init_only)
442{
443 struct unwind_table *table = handle;
444 struct unlink_table_info info;
445
446 if (!table || table == &root_table)
447 return;
448
449 if (init_only && table == last_table) {
450 table->init.pc = 0;
451 table->init.range = 0;
452 return;
453 }
454
455 info.table = table;
456 info.init_only = init_only;
457
458 unlink_table(&info); /* XXX: SMP */
459 kfree(table->header);
460 kfree(table);
461}
462
463#endif /* CONFIG_MODULES */
464
465static uleb128_t get_uleb128(const u8 **pcur, const u8 *end)
466{
467 const u8 *cur = *pcur;
468 uleb128_t value;
469 unsigned shift;
470
471 for (shift = 0, value = 0; cur < end; shift += 7) {
472 if (shift + 7 > 8 * sizeof(value)
473 && (*cur & 0x7fU) >= (1U << (8 * sizeof(value) - shift))) {
474 cur = end + 1;
475 break;
476 }
477 value |= (uleb128_t) (*cur & 0x7f) << shift;
478 if (!(*cur++ & 0x80))
479 break;
480 }
481 *pcur = cur;
482
483 return value;
484}
485
486static sleb128_t get_sleb128(const u8 **pcur, const u8 *end)
487{
488 const u8 *cur = *pcur;
489 sleb128_t value;
490 unsigned shift;
491
492 for (shift = 0, value = 0; cur < end; shift += 7) {
493 if (shift + 7 > 8 * sizeof(value)
494 && (*cur & 0x7fU) >= (1U << (8 * sizeof(value) - shift))) {
495 cur = end + 1;
496 break;
497 }
498 value |= (sleb128_t) (*cur & 0x7f) << shift;
499 if (!(*cur & 0x80)) {
500 value |= -(*cur++ & 0x40) << shift;
501 break;
502 }
503 }
504 *pcur = cur;
505
506 return value;
507}
508
509static const u32 *__cie_for_fde(const u32 *fde)
510{
511 const u32 *cie;
512
513 cie = fde + 1 - fde[1] / sizeof(*fde);
514
515 return cie;
516}
517
518static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *table)
519{
520 const u32 *cie;
521
522 if (!*fde || (*fde & (sizeof(*fde) - 1)))
523 return &bad_cie;
524
525 if (fde[1] == CIE_ID)
526 return ¬_fde; /* this is a CIE */
527
528 if ((fde[1] & (sizeof(*fde) - 1)))
529/* || fde[1] > (unsigned long)(fde + 1) - (unsigned long)table->address) */
530 return NULL; /* this is not a valid FDE */
531
532 cie = __cie_for_fde(fde);
533
534 if (*cie <= sizeof(*cie) + 4 || *cie >= fde[1] - sizeof(*fde)
535 || (*cie & (sizeof(*cie) - 1))
536 || (cie[1] != CIE_ID))
537 return NULL; /* this is not a (valid) CIE */
538 return cie;
539}
540
541static unsigned long read_pointer(const u8 **pLoc, const void *end,
542 signed ptrType)
543{
544 unsigned long value = 0;
545 union {
546 const u8 *p8;
547 const u16 *p16u;
548 const s16 *p16s;
549 const u32 *p32u;
550 const s32 *p32s;
551 const unsigned long *pul;
552 } ptr;
553
554 if (ptrType < 0 || ptrType == DW_EH_PE_omit)
555 return 0;
556 ptr.p8 = *pLoc;
557 switch (ptrType & DW_EH_PE_FORM) {
558 case DW_EH_PE_data2:
559 if (end < (const void *)(ptr.p16u + 1))
560 return 0;
561 if (ptrType & DW_EH_PE_signed)
562 value = get_unaligned((u16 *) ptr.p16s++);
563 else
564 value = get_unaligned((u16 *) ptr.p16u++);
565 break;
566 case DW_EH_PE_data4:
567#ifdef CONFIG_64BIT
568 if (end < (const void *)(ptr.p32u + 1))
569 return 0;
570 if (ptrType & DW_EH_PE_signed)
571 value = get_unaligned(ptr.p32s++);
572 else
573 value = get_unaligned(ptr.p32u++);
574 break;
575 case DW_EH_PE_data8:
576 BUILD_BUG_ON(sizeof(u64) != sizeof(value));
577#else
578 BUILD_BUG_ON(sizeof(u32) != sizeof(value));
579#endif
580 case DW_EH_PE_native:
581 if (end < (const void *)(ptr.pul + 1))
582 return 0;
583 value = get_unaligned((unsigned long *)ptr.pul++);
584 break;
585 case DW_EH_PE_leb128:
586 BUILD_BUG_ON(sizeof(uleb128_t) > sizeof(value));
587 value = ptrType & DW_EH_PE_signed ? get_sleb128(&ptr.p8, end)
588 : get_uleb128(&ptr.p8, end);
589 if ((const void *)ptr.p8 > end)
590 return 0;
591 break;
592 default:
593 return 0;
594 }
595 switch (ptrType & DW_EH_PE_ADJUST) {
596 case DW_EH_PE_abs:
597 break;
598 case DW_EH_PE_pcrel:
599 value += (unsigned long)*pLoc;
600 break;
601 default:
602 return 0;
603 }
604 if ((ptrType & DW_EH_PE_indirect)
605 && __get_user(value, (unsigned long __user *)value))
606 return 0;
607 *pLoc = ptr.p8;
608
609 return value;
610}
611
612static signed fde_pointer_type(const u32 *cie)
613{
614 const u8 *ptr = (const u8 *)(cie + 2);
615 unsigned version = *ptr;
616
617 if (*++ptr) {
618 const char *aug;
619 const u8 *end = (const u8 *)(cie + 1) + *cie;
620 uleb128_t len;
621
622 /* check if augmentation size is first (and thus present) */
623 if (*ptr != 'z')
624 return -1;
625
626 /* check if augmentation string is nul-terminated */
627 aug = (const void *)ptr;
628 ptr = memchr(aug, 0, end - ptr);
629 if (ptr == NULL)
630 return -1;
631
632 ++ptr; /* skip terminator */
633 get_uleb128(&ptr, end); /* skip code alignment */
634 get_sleb128(&ptr, end); /* skip data alignment */
635 /* skip return address column */
636 version <= 1 ? (void) ++ptr : (void)get_uleb128(&ptr, end);
637 len = get_uleb128(&ptr, end); /* augmentation length */
638
639 if (ptr + len < ptr || ptr + len > end)
640 return -1;
641
642 end = ptr + len;
643 while (*++aug) {
644 if (ptr >= end)
645 return -1;
646 switch (*aug) {
647 case 'L':
648 ++ptr;
649 break;
650 case 'P':{
651 signed ptrType = *ptr++;
652
653 if (!read_pointer(&ptr, end, ptrType)
654 || ptr > end)
655 return -1;
656 }
657 break;
658 case 'R':
659 return *ptr;
660 default:
661 return -1;
662 }
663 }
664 }
665 return DW_EH_PE_native | DW_EH_PE_abs;
666}
667
668static int advance_loc(unsigned long delta, struct unwind_state *state)
669{
670 state->loc += delta * state->codeAlign;
671
672 /* FIXME_Rajesh: Probably we are defining for the initial range as well;
673 return delta > 0;
674 */
675 unw_debug("delta %3lu => loc 0x%lx: ", delta, state->loc);
676 return 1;
677}
678
679static void set_rule(uleb128_t reg, enum item_location where, uleb128_t value,
680 struct unwind_state *state)
681{
682 if (reg < ARRAY_SIZE(state->regs)) {
683 state->regs[reg].where = where;
684 state->regs[reg].value = value;
685
686#ifdef UNWIND_DEBUG
687 unw_debug("r%lu: ", reg);
688 switch (where) {
689 case Nowhere:
690 unw_debug("s ");
691 break;
692 case Memory:
693 unw_debug("c(%lu) ", value);
694 break;
695 case Register:
696 unw_debug("r(%lu) ", value);
697 break;
698 case Value:
699 unw_debug("v(%lu) ", value);
700 break;
701 default:
702 break;
703 }
704#endif
705 }
706}
707
708static int processCFI(const u8 *start, const u8 *end, unsigned long targetLoc,
709 signed ptrType, struct unwind_state *state)
710{
711 union {
712 const u8 *p8;
713 const u16 *p16;
714 const u32 *p32;
715 } ptr;
716 int result = 1;
717 u8 opcode;
718
719 if (start != state->cieStart) {
720 state->loc = state->org;
721 result =
722 processCFI(state->cieStart, state->cieEnd, 0, ptrType,
723 state);
724 if (targetLoc == 0 && state->label == NULL)
725 return result;
726 }
727 for (ptr.p8 = start; result && ptr.p8 < end;) {
728 switch (*ptr.p8 >> 6) {
729 uleb128_t value;
730
731 case 0:
732 opcode = *ptr.p8++;
733
734 switch (opcode) {
735 case DW_CFA_nop:
736 unw_debug("cfa nop ");
737 break;
738 case DW_CFA_set_loc:
739 state->loc = read_pointer(&ptr.p8, end,
740 ptrType);
741 if (state->loc == 0)
742 result = 0;
743 unw_debug("cfa_set_loc: 0x%lx ", state->loc);
744 break;
745 case DW_CFA_advance_loc1:
746 unw_debug("\ncfa advance loc1:");
747 result = ptr.p8 < end
748 && advance_loc(*ptr.p8++, state);
749 break;
750 case DW_CFA_advance_loc2:
751 value = *ptr.p8++;
752 value += *ptr.p8++ << 8;
753 unw_debug("\ncfa advance loc2:");
754 result = ptr.p8 <= end + 2
755 /* && advance_loc(*ptr.p16++, state); */
756 && advance_loc(value, state);
757 break;
758 case DW_CFA_advance_loc4:
759 unw_debug("\ncfa advance loc4:");
760 result = ptr.p8 <= end + 4
761 && advance_loc(*ptr.p32++, state);
762 break;
763 case DW_CFA_offset_extended:
764 value = get_uleb128(&ptr.p8, end);
765 unw_debug("cfa_offset_extended: ");
766 set_rule(value, Memory,
767 get_uleb128(&ptr.p8, end), state);
768 break;
769 case DW_CFA_val_offset:
770 value = get_uleb128(&ptr.p8, end);
771 set_rule(value, Value,
772 get_uleb128(&ptr.p8, end), state);
773 break;
774 case DW_CFA_offset_extended_sf:
775 value = get_uleb128(&ptr.p8, end);
776 set_rule(value, Memory,
777 get_sleb128(&ptr.p8, end), state);
778 break;
779 case DW_CFA_val_offset_sf:
780 value = get_uleb128(&ptr.p8, end);
781 set_rule(value, Value,
782 get_sleb128(&ptr.p8, end), state);
783 break;
784 case DW_CFA_restore_extended:
785 unw_debug("cfa_restore_extended: ");
786 case DW_CFA_undefined:
787 unw_debug("cfa_undefined: ");
788 case DW_CFA_same_value:
789 unw_debug("cfa_same_value: ");
790 set_rule(get_uleb128(&ptr.p8, end), Nowhere, 0,
791 state);
792 break;
793 case DW_CFA_register:
794 unw_debug("cfa_register: ");
795 value = get_uleb128(&ptr.p8, end);
796 set_rule(value,
797 Register,
798 get_uleb128(&ptr.p8, end), state);
799 break;
800 case DW_CFA_remember_state:
801 unw_debug("cfa_remember_state: ");
802 if (ptr.p8 == state->label) {
803 state->label = NULL;
804 return 1;
805 }
806 if (state->stackDepth >= MAX_STACK_DEPTH)
807 return 0;
808 state->stack[state->stackDepth++] = ptr.p8;
809 break;
810 case DW_CFA_restore_state:
811 unw_debug("cfa_restore_state: ");
812 if (state->stackDepth) {
813 const uleb128_t loc = state->loc;
814 const u8 *label = state->label;
815
816 state->label =
817 state->stack[state->stackDepth - 1];
818 memcpy(&state->cfa, &badCFA,
819 sizeof(state->cfa));
820 memset(state->regs, 0,
821 sizeof(state->regs));
822 state->stackDepth = 0;
823 result =
824 processCFI(start, end, 0, ptrType,
825 state);
826 state->loc = loc;
827 state->label = label;
828 } else
829 return 0;
830 break;
831 case DW_CFA_def_cfa:
832 state->cfa.reg = get_uleb128(&ptr.p8, end);
833 unw_debug("cfa_def_cfa: r%lu ", state->cfa.reg);
834 /*nobreak*/
835 case DW_CFA_def_cfa_offset:
836 state->cfa.offs = get_uleb128(&ptr.p8, end);
837 unw_debug("cfa_def_cfa_offset: 0x%lx ",
838 state->cfa.offs);
839 break;
840 case DW_CFA_def_cfa_sf:
841 state->cfa.reg = get_uleb128(&ptr.p8, end);
842 /*nobreak */
843 case DW_CFA_def_cfa_offset_sf:
844 state->cfa.offs = get_sleb128(&ptr.p8, end)
845 * state->dataAlign;
846 break;
847 case DW_CFA_def_cfa_register:
848 unw_debug("cfa_def_cfa_regsiter: ");
849 state->cfa.reg = get_uleb128(&ptr.p8, end);
850 break;
851 /*todo case DW_CFA_def_cfa_expression: */
852 /*todo case DW_CFA_expression: */
853 /*todo case DW_CFA_val_expression: */
854 case DW_CFA_GNU_args_size:
855 get_uleb128(&ptr.p8, end);
856 break;
857 case DW_CFA_GNU_negative_offset_extended:
858 value = get_uleb128(&ptr.p8, end);
859 set_rule(value,
860 Memory,
861 (uleb128_t) 0 - get_uleb128(&ptr.p8,
862 end),
863 state);
864 break;
865 case DW_CFA_GNU_window_save:
866 default:
867 unw_debug("UNKNOWN OPCODE 0x%x\n", opcode);
868 result = 0;
869 break;
870 }
871 break;
872 case 1:
873 unw_debug("\ncfa_adv_loc: ");
874 result = advance_loc(*ptr.p8++ & 0x3f, state);
875 break;
876 case 2:
877 unw_debug("cfa_offset: ");
878 value = *ptr.p8++ & 0x3f;
879 set_rule(value, Memory, get_uleb128(&ptr.p8, end),
880 state);
881 break;
882 case 3:
883 unw_debug("cfa_restore: ");
884 set_rule(*ptr.p8++ & 0x3f, Nowhere, 0, state);
885 break;
886 }
887
888 if (ptr.p8 > end)
889 result = 0;
890 if (result && targetLoc != 0 && targetLoc < state->loc)
891 return 1;
892 }
893
894 return result && ptr.p8 == end && (targetLoc == 0 || (
895 /*todo While in theory this should apply, gcc in practice omits
896 everything past the function prolog, and hence the location
897 never reaches the end of the function.
898 targetLoc < state->loc && */ state->label == NULL));
899}
900
901/* Unwind to previous to frame. Returns 0 if successful, negative
902 * number in case of an error. */
903int arc_unwind(struct unwind_frame_info *frame)
904{
905#define FRAME_REG(r, t) (((t *)frame)[reg_info[r].offs])
906 const u32 *fde = NULL, *cie = NULL;
907 const u8 *ptr = NULL, *end = NULL;
908 unsigned long pc = UNW_PC(frame) - frame->call_frame;
909 unsigned long startLoc = 0, endLoc = 0, cfa;
910 unsigned i;
911 signed ptrType = -1;
912 uleb128_t retAddrReg = 0;
913 const struct unwind_table *table;
914 struct unwind_state state;
915 unsigned long *fptr;
916 unsigned long addr;
917
918 unw_debug("\n\nUNWIND FRAME:\n");
919 unw_debug("PC: 0x%lx BLINK: 0x%lx, SP: 0x%lx, FP: 0x%x\n",
920 UNW_PC(frame), UNW_BLINK(frame), UNW_SP(frame),
921 UNW_FP(frame));
922
923 if (UNW_PC(frame) == 0)
924 return -EINVAL;
925
926#ifdef UNWIND_DEBUG
927 {
928 unsigned long *sptr = (unsigned long *)UNW_SP(frame);
929 unw_debug("\nStack Dump:\n");
930 for (i = 0; i < 20; i++, sptr++)
931 unw_debug("0x%p: 0x%lx\n", sptr, *sptr);
932 unw_debug("\n");
933 }
934#endif
935
936 table = find_table(pc);
937 if (table != NULL
938 && !(table->size & (sizeof(*fde) - 1))) {
939 const u8 *hdr = table->header;
940 unsigned long tableSize;
941
942 smp_rmb();
943 if (hdr && hdr[0] == 1) {
944 switch (hdr[3] & DW_EH_PE_FORM) {
945 case DW_EH_PE_native:
946 tableSize = sizeof(unsigned long);
947 break;
948 case DW_EH_PE_data2:
949 tableSize = 2;
950 break;
951 case DW_EH_PE_data4:
952 tableSize = 4;
953 break;
954 case DW_EH_PE_data8:
955 tableSize = 8;
956 break;
957 default:
958 tableSize = 0;
959 break;
960 }
961 ptr = hdr + 4;
962 end = hdr + table->hdrsz;
963 if (tableSize && read_pointer(&ptr, end, hdr[1])
964 == (unsigned long)table->address
965 && (i = read_pointer(&ptr, end, hdr[2])) > 0
966 && i == (end - ptr) / (2 * tableSize)
967 && !((end - ptr) % (2 * tableSize))) {
968 do {
969 const u8 *cur =
970 ptr + (i / 2) * (2 * tableSize);
971
972 startLoc = read_pointer(&cur,
973 cur + tableSize,
974 hdr[3]);
975 if (pc < startLoc)
976 i /= 2;
977 else {
978 ptr = cur - tableSize;
979 i = (i + 1) / 2;
980 }
981 } while (startLoc && i > 1);
982 if (i == 1
983 && (startLoc = read_pointer(&ptr,
984 ptr + tableSize,
985 hdr[3])) != 0
986 && pc >= startLoc)
987 fde = (void *)read_pointer(&ptr,
988 ptr +
989 tableSize,
990 hdr[3]);
991 }
992 }
993
994 if (fde != NULL) {
995 cie = cie_for_fde(fde, table);
996 ptr = (const u8 *)(fde + 2);
997 if (cie != NULL
998 && cie != &bad_cie
999 && cie != ¬_fde
1000 && (ptrType = fde_pointer_type(cie)) >= 0
1001 && read_pointer(&ptr,
1002 (const u8 *)(fde + 1) + *fde,
1003 ptrType) == startLoc) {
1004 if (!(ptrType & DW_EH_PE_indirect))
1005 ptrType &=
1006 DW_EH_PE_FORM | DW_EH_PE_signed;
1007 endLoc =
1008 startLoc + read_pointer(&ptr,
1009 (const u8 *)(fde +
1010 1) +
1011 *fde, ptrType);
1012 if (pc >= endLoc) {
1013 fde = NULL;
1014 cie = NULL;
1015 }
1016 } else {
1017 fde = NULL;
1018 cie = NULL;
1019 }
1020 }
1021 }
1022 if (cie != NULL) {
1023 memset(&state, 0, sizeof(state));
1024 state.cieEnd = ptr; /* keep here temporarily */
1025 ptr = (const u8 *)(cie + 2);
1026 end = (const u8 *)(cie + 1) + *cie;
1027 frame->call_frame = 1;
1028 if (*++ptr) {
1029 /* check if augmentation size is first (thus present) */
1030 if (*ptr == 'z') {
1031 while (++ptr < end && *ptr) {
1032 switch (*ptr) {
1033 /* chk for ignorable or already handled
1034 * nul-terminated augmentation string */
1035 case 'L':
1036 case 'P':
1037 case 'R':
1038 continue;
1039 case 'S':
1040 frame->call_frame = 0;
1041 continue;
1042 default:
1043 break;
1044 }
1045 break;
1046 }
1047 }
1048 if (ptr >= end || *ptr)
1049 cie = NULL;
1050 }
1051 ++ptr;
1052 }
1053 if (cie != NULL) {
1054 /* get code aligment factor */
1055 state.codeAlign = get_uleb128(&ptr, end);
1056 /* get data aligment factor */
1057 state.dataAlign = get_sleb128(&ptr, end);
1058 if (state.codeAlign == 0 || state.dataAlign == 0 || ptr >= end)
1059 cie = NULL;
1060 else {
1061 retAddrReg =
1062 state.version <= 1 ? *ptr++ : get_uleb128(&ptr,
1063 end);
1064 unw_debug("CIE Frame Info:\n");
1065 unw_debug("return Address register 0x%lx\n",
1066 retAddrReg);
1067 unw_debug("data Align: %ld\n", state.dataAlign);
1068 unw_debug("code Align: %lu\n", state.codeAlign);
1069 /* skip augmentation */
1070 if (((const char *)(cie + 2))[1] == 'z') {
1071 uleb128_t augSize = get_uleb128(&ptr, end);
1072
1073 ptr += augSize;
1074 }
1075 if (ptr > end || retAddrReg >= ARRAY_SIZE(reg_info)
1076 || REG_INVALID(retAddrReg)
1077 || reg_info[retAddrReg].width !=
1078 sizeof(unsigned long))
1079 cie = NULL;
1080 }
1081 }
1082 if (cie != NULL) {
1083 state.cieStart = ptr;
1084 ptr = state.cieEnd;
1085 state.cieEnd = end;
1086 end = (const u8 *)(fde + 1) + *fde;
1087 /* skip augmentation */
1088 if (((const char *)(cie + 2))[1] == 'z') {
1089 uleb128_t augSize = get_uleb128(&ptr, end);
1090
1091 if ((ptr += augSize) > end)
1092 fde = NULL;
1093 }
1094 }
1095 if (cie == NULL || fde == NULL) {
1096#ifdef CONFIG_FRAME_POINTER
1097 unsigned long top, bottom;
1098
1099 top = STACK_TOP_UNW(frame->task);
1100 bottom = STACK_BOTTOM_UNW(frame->task);
1101#if FRAME_RETADDR_OFFSET < 0
1102 if (UNW_SP(frame) < top && UNW_FP(frame) <= UNW_SP(frame)
1103 && bottom < UNW_FP(frame)
1104#else
1105 if (UNW_SP(frame) > top && UNW_FP(frame) >= UNW_SP(frame)
1106 && bottom > UNW_FP(frame)
1107#endif
1108 && !((UNW_SP(frame) | UNW_FP(frame))
1109 & (sizeof(unsigned long) - 1))) {
1110 unsigned long link;
1111
1112 if (!__get_user(link, (unsigned long *)
1113 (UNW_FP(frame) + FRAME_LINK_OFFSET))
1114#if FRAME_RETADDR_OFFSET < 0
1115 && link > bottom && link < UNW_FP(frame)
1116#else
1117 && link > UNW_FP(frame) && link < bottom
1118#endif
1119 && !(link & (sizeof(link) - 1))
1120 && !__get_user(UNW_PC(frame),
1121 (unsigned long *)(UNW_FP(frame)
1122 + FRAME_RETADDR_OFFSET)))
1123 {
1124 UNW_SP(frame) =
1125 UNW_FP(frame) + FRAME_RETADDR_OFFSET
1126#if FRAME_RETADDR_OFFSET < 0
1127 -
1128#else
1129 +
1130#endif
1131 sizeof(UNW_PC(frame));
1132 UNW_FP(frame) = link;
1133 return 0;
1134 }
1135 }
1136#endif
1137 return -ENXIO;
1138 }
1139 state.org = startLoc;
1140 memcpy(&state.cfa, &badCFA, sizeof(state.cfa));
1141
1142 unw_debug("\nProcess instructions\n");
1143
1144 /* process instructions
1145 * For ARC, we optimize by having blink(retAddrReg) with
1146 * the sameValue in the leaf function, so we should not check
1147 * state.regs[retAddrReg].where == Nowhere
1148 */
1149 if (!processCFI(ptr, end, pc, ptrType, &state)
1150 || state.loc > endLoc
1151/* || state.regs[retAddrReg].where == Nowhere */
1152 || state.cfa.reg >= ARRAY_SIZE(reg_info)
1153 || reg_info[state.cfa.reg].width != sizeof(unsigned long)
1154 || state.cfa.offs % sizeof(unsigned long))
1155 return -EIO;
1156
1157#ifdef UNWIND_DEBUG
1158 unw_debug("\n");
1159
1160 unw_debug("\nRegister State Based on the rules parsed from FDE:\n");
1161 for (i = 0; i < ARRAY_SIZE(state.regs); ++i) {
1162
1163 if (REG_INVALID(i))
1164 continue;
1165
1166 switch (state.regs[i].where) {
1167 case Nowhere:
1168 break;
1169 case Memory:
1170 unw_debug(" r%d: c(%lu),", i, state.regs[i].value);
1171 break;
1172 case Register:
1173 unw_debug(" r%d: r(%lu),", i, state.regs[i].value);
1174 break;
1175 case Value:
1176 unw_debug(" r%d: v(%lu),", i, state.regs[i].value);
1177 break;
1178 }
1179 }
1180
1181 unw_debug("\n");
1182#endif
1183
1184 /* update frame */
1185#ifndef CONFIG_AS_CFI_SIGNAL_FRAME
1186 if (frame->call_frame
1187 && !UNW_DEFAULT_RA(state.regs[retAddrReg], state.dataAlign))
1188 frame->call_frame = 0;
1189#endif
1190 cfa = FRAME_REG(state.cfa.reg, unsigned long) + state.cfa.offs;
1191 startLoc = min_t(unsigned long, UNW_SP(frame), cfa);
1192 endLoc = max_t(unsigned long, UNW_SP(frame), cfa);
1193 if (STACK_LIMIT(startLoc) != STACK_LIMIT(endLoc)) {
1194 startLoc = min(STACK_LIMIT(cfa), cfa);
1195 endLoc = max(STACK_LIMIT(cfa), cfa);
1196 }
1197
1198 unw_debug("\nCFA reg: 0x%lx, offset: 0x%lx => 0x%lx\n",
1199 state.cfa.reg, state.cfa.offs, cfa);
1200
1201 for (i = 0; i < ARRAY_SIZE(state.regs); ++i) {
1202 if (REG_INVALID(i)) {
1203 if (state.regs[i].where == Nowhere)
1204 continue;
1205 return -EIO;
1206 }
1207 switch (state.regs[i].where) {
1208 default:
1209 break;
1210 case Register:
1211 if (state.regs[i].value >= ARRAY_SIZE(reg_info)
1212 || REG_INVALID(state.regs[i].value)
1213 || reg_info[i].width >
1214 reg_info[state.regs[i].value].width)
1215 return -EIO;
1216 switch (reg_info[state.regs[i].value].width) {
1217 case sizeof(u8):
1218 state.regs[i].value =
1219 FRAME_REG(state.regs[i].value, const u8);
1220 break;
1221 case sizeof(u16):
1222 state.regs[i].value =
1223 FRAME_REG(state.regs[i].value, const u16);
1224 break;
1225 case sizeof(u32):
1226 state.regs[i].value =
1227 FRAME_REG(state.regs[i].value, const u32);
1228 break;
1229#ifdef CONFIG_64BIT
1230 case sizeof(u64):
1231 state.regs[i].value =
1232 FRAME_REG(state.regs[i].value, const u64);
1233 break;
1234#endif
1235 default:
1236 return -EIO;
1237 }
1238 break;
1239 }
1240 }
1241
1242 unw_debug("\nRegister state after evaluation with realtime Stack:\n");
1243 fptr = (unsigned long *)(&frame->regs);
1244 for (i = 0; i < ARRAY_SIZE(state.regs); ++i, fptr++) {
1245
1246 if (REG_INVALID(i))
1247 continue;
1248 switch (state.regs[i].where) {
1249 case Nowhere:
1250 if (reg_info[i].width != sizeof(UNW_SP(frame))
1251 || &FRAME_REG(i, __typeof__(UNW_SP(frame)))
1252 != &UNW_SP(frame))
1253 continue;
1254 UNW_SP(frame) = cfa;
1255 break;
1256 case Register:
1257 switch (reg_info[i].width) {
1258 case sizeof(u8):
1259 FRAME_REG(i, u8) = state.regs[i].value;
1260 break;
1261 case sizeof(u16):
1262 FRAME_REG(i, u16) = state.regs[i].value;
1263 break;
1264 case sizeof(u32):
1265 FRAME_REG(i, u32) = state.regs[i].value;
1266 break;
1267#ifdef CONFIG_64BIT
1268 case sizeof(u64):
1269 FRAME_REG(i, u64) = state.regs[i].value;
1270 break;
1271#endif
1272 default:
1273 return -EIO;
1274 }
1275 break;
1276 case Value:
1277 if (reg_info[i].width != sizeof(unsigned long))
1278 return -EIO;
1279 FRAME_REG(i, unsigned long) = cfa + state.regs[i].value
1280 * state.dataAlign;
1281 break;
1282 case Memory:
1283 addr = cfa + state.regs[i].value * state.dataAlign;
1284
1285 if ((state.regs[i].value * state.dataAlign)
1286 % sizeof(unsigned long)
1287 || addr < startLoc
1288 || addr + sizeof(unsigned long) < addr
1289 || addr + sizeof(unsigned long) > endLoc)
1290 return -EIO;
1291
1292 switch (reg_info[i].width) {
1293 case sizeof(u8):
1294 __get_user(FRAME_REG(i, u8),
1295 (u8 __user *)addr);
1296 break;
1297 case sizeof(u16):
1298 __get_user(FRAME_REG(i, u16),
1299 (u16 __user *)addr);
1300 break;
1301 case sizeof(u32):
1302 __get_user(FRAME_REG(i, u32),
1303 (u32 __user *)addr);
1304 break;
1305#ifdef CONFIG_64BIT
1306 case sizeof(u64):
1307 __get_user(FRAME_REG(i, u64),
1308 (u64 __user *)addr);
1309 break;
1310#endif
1311 default:
1312 return -EIO;
1313 }
1314
1315 break;
1316 }
1317 unw_debug("r%d: 0x%lx ", i, *fptr);
1318 }
1319
1320 return 0;
1321#undef FRAME_REG
1322}
1323EXPORT_SYMBOL(arc_unwind);
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
28extern 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
34int dbg_unw;
35#define unw_debug(fmt, ...) \
36do { \
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
55static const struct {
56 unsigned offs:BITS_PER_LONG / 2;
57 unsigned width:BITS_PER_LONG / 2;
58} reg_info[] = {
59UNW_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
114typedef unsigned long uleb128_t;
115typedef signed long sleb128_t;
116
117static 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
130struct unwind_item {
131 enum item_location {
132 Nowhere,
133 Memory,
134 Register,
135 Value
136 } where;
137 uleb128_t value;
138};
139
140struct 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
155static const struct cfa badCFA = { ARRAY_SIZE(reg_info), 1 };
156
157static 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
171static unsigned long read_pointer(const u8 **pLoc,
172 const void *end, signed ptrType);
173static 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 */
180static 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
186static void *unw_hdr_alloc(unsigned long sz)
187{
188 return kmalloc(sz, GFP_KERNEL);
189}
190
191static 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
223void __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
233static const u32 bad_cie, not_fde;
234static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *);
235static signed fde_pointer_type(const u32 *cie);
236
237struct eh_frame_hdr_table_entry {
238 unsigned long start, fde;
239};
240
241static 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
249static 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
263static 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 == ¬_fde)
297 continue;
298 if (cie == NULL || cie == &bad_cie)
299 goto ret_err;
300 ptrType = fde_pointer_type(cie);
301 if (ptrType < 0)
302 goto ret_err;
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 goto ret_err;
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 goto ret_err;
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 ptr = (const u8 *)(fde + 2);
347 header->table[n].start = read_pointer(&ptr,
348 (const u8 *)(fde + 1) +
349 *fde,
350 fde_pointer_type(cie));
351 header->table[n].fde = (unsigned long)fde;
352 ++n;
353 }
354 WARN_ON(n != header->fde_count);
355
356 sort(header->table,
357 n,
358 sizeof(*header->table),
359 cmp_eh_frame_hdr_table_entries, swap_eh_frame_hdr_table_entries);
360
361 table->hdrsz = hdrSize;
362 smp_wmb();
363 table->header = (const void *)header;
364 return;
365
366ret_err:
367 panic("Attention !!! Dwarf FDE parsing errors\n");;
368}
369
370#ifdef CONFIG_MODULES
371
372static struct unwind_table *last_table;
373
374/* Must be called with module_mutex held. */
375void *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->core_layout.base, module->core_layout.size,
389 module->init_layout.base, module->init_layout.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
408struct unlink_table_info {
409 struct unwind_table *table;
410 int init_only;
411};
412
413static 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. */
439void 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
463static 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
484static 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
507static 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 ¬_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 return NULL; /* this is not a (valid) CIE */
528 return cie;
529}
530
531static unsigned long read_pointer(const u8 **pLoc, const void *end,
532 signed ptrType)
533{
534 unsigned long value = 0;
535 union {
536 const u8 *p8;
537 const u16 *p16u;
538 const s16 *p16s;
539 const u32 *p32u;
540 const s32 *p32s;
541 const unsigned long *pul;
542 } ptr;
543
544 if (ptrType < 0 || ptrType == DW_EH_PE_omit)
545 return 0;
546 ptr.p8 = *pLoc;
547 switch (ptrType & DW_EH_PE_FORM) {
548 case DW_EH_PE_data2:
549 if (end < (const void *)(ptr.p16u + 1))
550 return 0;
551 if (ptrType & DW_EH_PE_signed)
552 value = get_unaligned((u16 *) ptr.p16s++);
553 else
554 value = get_unaligned((u16 *) ptr.p16u++);
555 break;
556 case DW_EH_PE_data4:
557#ifdef CONFIG_64BIT
558 if (end < (const void *)(ptr.p32u + 1))
559 return 0;
560 if (ptrType & DW_EH_PE_signed)
561 value = get_unaligned(ptr.p32s++);
562 else
563 value = get_unaligned(ptr.p32u++);
564 break;
565 case DW_EH_PE_data8:
566 BUILD_BUG_ON(sizeof(u64) != sizeof(value));
567#else
568 BUILD_BUG_ON(sizeof(u32) != sizeof(value));
569#endif
570 case DW_EH_PE_native:
571 if (end < (const void *)(ptr.pul + 1))
572 return 0;
573 value = get_unaligned((unsigned long *)ptr.pul++);
574 break;
575 case DW_EH_PE_leb128:
576 BUILD_BUG_ON(sizeof(uleb128_t) > sizeof(value));
577 value = ptrType & DW_EH_PE_signed ? get_sleb128(&ptr.p8, end)
578 : get_uleb128(&ptr.p8, end);
579 if ((const void *)ptr.p8 > end)
580 return 0;
581 break;
582 default:
583 return 0;
584 }
585 switch (ptrType & DW_EH_PE_ADJUST) {
586 case DW_EH_PE_abs:
587 break;
588 case DW_EH_PE_pcrel:
589 value += (unsigned long)*pLoc;
590 break;
591 default:
592 return 0;
593 }
594 if ((ptrType & DW_EH_PE_indirect)
595 && __get_user(value, (unsigned long __user *)value))
596 return 0;
597 *pLoc = ptr.p8;
598
599 return value;
600}
601
602static signed fde_pointer_type(const u32 *cie)
603{
604 const u8 *ptr = (const u8 *)(cie + 2);
605 unsigned version = *ptr;
606
607 if (*++ptr) {
608 const char *aug;
609 const u8 *end = (const u8 *)(cie + 1) + *cie;
610 uleb128_t len;
611
612 /* check if augmentation size is first (and thus present) */
613 if (*ptr != 'z')
614 return -1;
615
616 /* check if augmentation string is nul-terminated */
617 aug = (const void *)ptr;
618 ptr = memchr(aug, 0, end - ptr);
619 if (ptr == NULL)
620 return -1;
621
622 ++ptr; /* skip terminator */
623 get_uleb128(&ptr, end); /* skip code alignment */
624 get_sleb128(&ptr, end); /* skip data alignment */
625 /* skip return address column */
626 version <= 1 ? (void) ++ptr : (void)get_uleb128(&ptr, end);
627 len = get_uleb128(&ptr, end); /* augmentation length */
628
629 if (ptr + len < ptr || ptr + len > end)
630 return -1;
631
632 end = ptr + len;
633 while (*++aug) {
634 if (ptr >= end)
635 return -1;
636 switch (*aug) {
637 case 'L':
638 ++ptr;
639 break;
640 case 'P':{
641 signed ptrType = *ptr++;
642
643 if (!read_pointer(&ptr, end, ptrType)
644 || ptr > end)
645 return -1;
646 }
647 break;
648 case 'R':
649 return *ptr;
650 default:
651 return -1;
652 }
653 }
654 }
655 return DW_EH_PE_native | DW_EH_PE_abs;
656}
657
658static int advance_loc(unsigned long delta, struct unwind_state *state)
659{
660 state->loc += delta * state->codeAlign;
661
662 /* FIXME_Rajesh: Probably we are defining for the initial range as well;
663 return delta > 0;
664 */
665 unw_debug("delta %3lu => loc 0x%lx: ", delta, state->loc);
666 return 1;
667}
668
669static void set_rule(uleb128_t reg, enum item_location where, uleb128_t value,
670 struct unwind_state *state)
671{
672 if (reg < ARRAY_SIZE(state->regs)) {
673 state->regs[reg].where = where;
674 state->regs[reg].value = value;
675
676#ifdef UNWIND_DEBUG
677 unw_debug("r%lu: ", reg);
678 switch (where) {
679 case Nowhere:
680 unw_debug("s ");
681 break;
682 case Memory:
683 unw_debug("c(%lu) ", value);
684 break;
685 case Register:
686 unw_debug("r(%lu) ", value);
687 break;
688 case Value:
689 unw_debug("v(%lu) ", value);
690 break;
691 default:
692 break;
693 }
694#endif
695 }
696}
697
698static int processCFI(const u8 *start, const u8 *end, unsigned long targetLoc,
699 signed ptrType, struct unwind_state *state)
700{
701 union {
702 const u8 *p8;
703 const u16 *p16;
704 const u32 *p32;
705 } ptr;
706 int result = 1;
707 u8 opcode;
708
709 if (start != state->cieStart) {
710 state->loc = state->org;
711 result =
712 processCFI(state->cieStart, state->cieEnd, 0, ptrType,
713 state);
714 if (targetLoc == 0 && state->label == NULL)
715 return result;
716 }
717 for (ptr.p8 = start; result && ptr.p8 < end;) {
718 switch (*ptr.p8 >> 6) {
719 uleb128_t value;
720
721 case 0:
722 opcode = *ptr.p8++;
723
724 switch (opcode) {
725 case DW_CFA_nop:
726 unw_debug("cfa nop ");
727 break;
728 case DW_CFA_set_loc:
729 state->loc = read_pointer(&ptr.p8, end,
730 ptrType);
731 if (state->loc == 0)
732 result = 0;
733 unw_debug("cfa_set_loc: 0x%lx ", state->loc);
734 break;
735 case DW_CFA_advance_loc1:
736 unw_debug("\ncfa advance loc1:");
737 result = ptr.p8 < end
738 && advance_loc(*ptr.p8++, state);
739 break;
740 case DW_CFA_advance_loc2:
741 value = *ptr.p8++;
742 value += *ptr.p8++ << 8;
743 unw_debug("\ncfa advance loc2:");
744 result = ptr.p8 <= end + 2
745 /* && advance_loc(*ptr.p16++, state); */
746 && advance_loc(value, state);
747 break;
748 case DW_CFA_advance_loc4:
749 unw_debug("\ncfa advance loc4:");
750 result = ptr.p8 <= end + 4
751 && advance_loc(*ptr.p32++, state);
752 break;
753 case DW_CFA_offset_extended:
754 value = get_uleb128(&ptr.p8, end);
755 unw_debug("cfa_offset_extended: ");
756 set_rule(value, Memory,
757 get_uleb128(&ptr.p8, end), state);
758 break;
759 case DW_CFA_val_offset:
760 value = get_uleb128(&ptr.p8, end);
761 set_rule(value, Value,
762 get_uleb128(&ptr.p8, end), state);
763 break;
764 case DW_CFA_offset_extended_sf:
765 value = get_uleb128(&ptr.p8, end);
766 set_rule(value, Memory,
767 get_sleb128(&ptr.p8, end), state);
768 break;
769 case DW_CFA_val_offset_sf:
770 value = get_uleb128(&ptr.p8, end);
771 set_rule(value, Value,
772 get_sleb128(&ptr.p8, end), state);
773 break;
774 case DW_CFA_restore_extended:
775 unw_debug("cfa_restore_extended: ");
776 case DW_CFA_undefined:
777 unw_debug("cfa_undefined: ");
778 case DW_CFA_same_value:
779 unw_debug("cfa_same_value: ");
780 set_rule(get_uleb128(&ptr.p8, end), Nowhere, 0,
781 state);
782 break;
783 case DW_CFA_register:
784 unw_debug("cfa_register: ");
785 value = get_uleb128(&ptr.p8, end);
786 set_rule(value,
787 Register,
788 get_uleb128(&ptr.p8, end), state);
789 break;
790 case DW_CFA_remember_state:
791 unw_debug("cfa_remember_state: ");
792 if (ptr.p8 == state->label) {
793 state->label = NULL;
794 return 1;
795 }
796 if (state->stackDepth >= MAX_STACK_DEPTH)
797 return 0;
798 state->stack[state->stackDepth++] = ptr.p8;
799 break;
800 case DW_CFA_restore_state:
801 unw_debug("cfa_restore_state: ");
802 if (state->stackDepth) {
803 const uleb128_t loc = state->loc;
804 const u8 *label = state->label;
805
806 state->label =
807 state->stack[state->stackDepth - 1];
808 memcpy(&state->cfa, &badCFA,
809 sizeof(state->cfa));
810 memset(state->regs, 0,
811 sizeof(state->regs));
812 state->stackDepth = 0;
813 result =
814 processCFI(start, end, 0, ptrType,
815 state);
816 state->loc = loc;
817 state->label = label;
818 } else
819 return 0;
820 break;
821 case DW_CFA_def_cfa:
822 state->cfa.reg = get_uleb128(&ptr.p8, end);
823 unw_debug("cfa_def_cfa: r%lu ", state->cfa.reg);
824 /*nobreak*/
825 case DW_CFA_def_cfa_offset:
826 state->cfa.offs = get_uleb128(&ptr.p8, end);
827 unw_debug("cfa_def_cfa_offset: 0x%lx ",
828 state->cfa.offs);
829 break;
830 case DW_CFA_def_cfa_sf:
831 state->cfa.reg = get_uleb128(&ptr.p8, end);
832 /*nobreak */
833 case DW_CFA_def_cfa_offset_sf:
834 state->cfa.offs = get_sleb128(&ptr.p8, end)
835 * state->dataAlign;
836 break;
837 case DW_CFA_def_cfa_register:
838 unw_debug("cfa_def_cfa_regsiter: ");
839 state->cfa.reg = get_uleb128(&ptr.p8, end);
840 break;
841 /*todo case DW_CFA_def_cfa_expression: */
842 /*todo case DW_CFA_expression: */
843 /*todo case DW_CFA_val_expression: */
844 case DW_CFA_GNU_args_size:
845 get_uleb128(&ptr.p8, end);
846 break;
847 case DW_CFA_GNU_negative_offset_extended:
848 value = get_uleb128(&ptr.p8, end);
849 set_rule(value,
850 Memory,
851 (uleb128_t) 0 - get_uleb128(&ptr.p8,
852 end),
853 state);
854 break;
855 case DW_CFA_GNU_window_save:
856 default:
857 unw_debug("UNKNOWN OPCODE 0x%x\n", opcode);
858 result = 0;
859 break;
860 }
861 break;
862 case 1:
863 unw_debug("\ncfa_adv_loc: ");
864 result = advance_loc(*ptr.p8++ & 0x3f, state);
865 break;
866 case 2:
867 unw_debug("cfa_offset: ");
868 value = *ptr.p8++ & 0x3f;
869 set_rule(value, Memory, get_uleb128(&ptr.p8, end),
870 state);
871 break;
872 case 3:
873 unw_debug("cfa_restore: ");
874 set_rule(*ptr.p8++ & 0x3f, Nowhere, 0, state);
875 break;
876 }
877
878 if (ptr.p8 > end)
879 result = 0;
880 if (result && targetLoc != 0 && targetLoc < state->loc)
881 return 1;
882 }
883
884 return result && ptr.p8 == end && (targetLoc == 0 || (
885 /*todo While in theory this should apply, gcc in practice omits
886 everything past the function prolog, and hence the location
887 never reaches the end of the function.
888 targetLoc < state->loc && */ state->label == NULL));
889}
890
891/* Unwind to previous to frame. Returns 0 if successful, negative
892 * number in case of an error. */
893int arc_unwind(struct unwind_frame_info *frame)
894{
895#define FRAME_REG(r, t) (((t *)frame)[reg_info[r].offs])
896 const u32 *fde = NULL, *cie = NULL;
897 const u8 *ptr = NULL, *end = NULL;
898 unsigned long pc = UNW_PC(frame) - frame->call_frame;
899 unsigned long startLoc = 0, endLoc = 0, cfa;
900 unsigned i;
901 signed ptrType = -1;
902 uleb128_t retAddrReg = 0;
903 const struct unwind_table *table;
904 struct unwind_state state;
905 unsigned long *fptr;
906 unsigned long addr;
907
908 unw_debug("\n\nUNWIND FRAME:\n");
909 unw_debug("PC: 0x%lx BLINK: 0x%lx, SP: 0x%lx, FP: 0x%x\n",
910 UNW_PC(frame), UNW_BLINK(frame), UNW_SP(frame),
911 UNW_FP(frame));
912
913 if (UNW_PC(frame) == 0)
914 return -EINVAL;
915
916#ifdef UNWIND_DEBUG
917 {
918 unsigned long *sptr = (unsigned long *)UNW_SP(frame);
919 unw_debug("\nStack Dump:\n");
920 for (i = 0; i < 20; i++, sptr++)
921 unw_debug("0x%p: 0x%lx\n", sptr, *sptr);
922 unw_debug("\n");
923 }
924#endif
925
926 table = find_table(pc);
927 if (table != NULL
928 && !(table->size & (sizeof(*fde) - 1))) {
929 const u8 *hdr = table->header;
930 unsigned long tableSize;
931
932 smp_rmb();
933 if (hdr && hdr[0] == 1) {
934 switch (hdr[3] & DW_EH_PE_FORM) {
935 case DW_EH_PE_native:
936 tableSize = sizeof(unsigned long);
937 break;
938 case DW_EH_PE_data2:
939 tableSize = 2;
940 break;
941 case DW_EH_PE_data4:
942 tableSize = 4;
943 break;
944 case DW_EH_PE_data8:
945 tableSize = 8;
946 break;
947 default:
948 tableSize = 0;
949 break;
950 }
951 ptr = hdr + 4;
952 end = hdr + table->hdrsz;
953 if (tableSize && read_pointer(&ptr, end, hdr[1])
954 == (unsigned long)table->address
955 && (i = read_pointer(&ptr, end, hdr[2])) > 0
956 && i == (end - ptr) / (2 * tableSize)
957 && !((end - ptr) % (2 * tableSize))) {
958 do {
959 const u8 *cur =
960 ptr + (i / 2) * (2 * tableSize);
961
962 startLoc = read_pointer(&cur,
963 cur + tableSize,
964 hdr[3]);
965 if (pc < startLoc)
966 i /= 2;
967 else {
968 ptr = cur - tableSize;
969 i = (i + 1) / 2;
970 }
971 } while (startLoc && i > 1);
972 if (i == 1
973 && (startLoc = read_pointer(&ptr,
974 ptr + tableSize,
975 hdr[3])) != 0
976 && pc >= startLoc)
977 fde = (void *)read_pointer(&ptr,
978 ptr +
979 tableSize,
980 hdr[3]);
981 }
982 }
983
984 if (fde != NULL) {
985 cie = cie_for_fde(fde, table);
986 ptr = (const u8 *)(fde + 2);
987 if (cie != NULL
988 && cie != &bad_cie
989 && cie != ¬_fde
990 && (ptrType = fde_pointer_type(cie)) >= 0
991 && read_pointer(&ptr,
992 (const u8 *)(fde + 1) + *fde,
993 ptrType) == startLoc) {
994 if (!(ptrType & DW_EH_PE_indirect))
995 ptrType &=
996 DW_EH_PE_FORM | DW_EH_PE_signed;
997 endLoc =
998 startLoc + read_pointer(&ptr,
999 (const u8 *)(fde +
1000 1) +
1001 *fde, ptrType);
1002 if (pc >= endLoc) {
1003 fde = NULL;
1004 cie = NULL;
1005 }
1006 } else {
1007 fde = NULL;
1008 cie = NULL;
1009 }
1010 }
1011 }
1012 if (cie != NULL) {
1013 memset(&state, 0, sizeof(state));
1014 state.cieEnd = ptr; /* keep here temporarily */
1015 ptr = (const u8 *)(cie + 2);
1016 end = (const u8 *)(cie + 1) + *cie;
1017 frame->call_frame = 1;
1018 if (*++ptr) {
1019 /* check if augmentation size is first (thus present) */
1020 if (*ptr == 'z') {
1021 while (++ptr < end && *ptr) {
1022 switch (*ptr) {
1023 /* chk for ignorable or already handled
1024 * nul-terminated augmentation string */
1025 case 'L':
1026 case 'P':
1027 case 'R':
1028 continue;
1029 case 'S':
1030 frame->call_frame = 0;
1031 continue;
1032 default:
1033 break;
1034 }
1035 break;
1036 }
1037 }
1038 if (ptr >= end || *ptr)
1039 cie = NULL;
1040 }
1041 ++ptr;
1042 }
1043 if (cie != NULL) {
1044 /* get code aligment factor */
1045 state.codeAlign = get_uleb128(&ptr, end);
1046 /* get data aligment factor */
1047 state.dataAlign = get_sleb128(&ptr, end);
1048 if (state.codeAlign == 0 || state.dataAlign == 0 || ptr >= end)
1049 cie = NULL;
1050 else {
1051 retAddrReg =
1052 state.version <= 1 ? *ptr++ : get_uleb128(&ptr,
1053 end);
1054 unw_debug("CIE Frame Info:\n");
1055 unw_debug("return Address register 0x%lx\n",
1056 retAddrReg);
1057 unw_debug("data Align: %ld\n", state.dataAlign);
1058 unw_debug("code Align: %lu\n", state.codeAlign);
1059 /* skip augmentation */
1060 if (((const char *)(cie + 2))[1] == 'z') {
1061 uleb128_t augSize = get_uleb128(&ptr, end);
1062
1063 ptr += augSize;
1064 }
1065 if (ptr > end || retAddrReg >= ARRAY_SIZE(reg_info)
1066 || REG_INVALID(retAddrReg)
1067 || reg_info[retAddrReg].width !=
1068 sizeof(unsigned long))
1069 cie = NULL;
1070 }
1071 }
1072 if (cie != NULL) {
1073 state.cieStart = ptr;
1074 ptr = state.cieEnd;
1075 state.cieEnd = end;
1076 end = (const u8 *)(fde + 1) + *fde;
1077 /* skip augmentation */
1078 if (((const char *)(cie + 2))[1] == 'z') {
1079 uleb128_t augSize = get_uleb128(&ptr, end);
1080
1081 if ((ptr += augSize) > end)
1082 fde = NULL;
1083 }
1084 }
1085 if (cie == NULL || fde == NULL) {
1086#ifdef CONFIG_FRAME_POINTER
1087 unsigned long top, bottom;
1088
1089 top = STACK_TOP_UNW(frame->task);
1090 bottom = STACK_BOTTOM_UNW(frame->task);
1091#if FRAME_RETADDR_OFFSET < 0
1092 if (UNW_SP(frame) < top && UNW_FP(frame) <= UNW_SP(frame)
1093 && bottom < UNW_FP(frame)
1094#else
1095 if (UNW_SP(frame) > top && UNW_FP(frame) >= UNW_SP(frame)
1096 && bottom > UNW_FP(frame)
1097#endif
1098 && !((UNW_SP(frame) | UNW_FP(frame))
1099 & (sizeof(unsigned long) - 1))) {
1100 unsigned long link;
1101
1102 if (!__get_user(link, (unsigned long *)
1103 (UNW_FP(frame) + FRAME_LINK_OFFSET))
1104#if FRAME_RETADDR_OFFSET < 0
1105 && link > bottom && link < UNW_FP(frame)
1106#else
1107 && link > UNW_FP(frame) && link < bottom
1108#endif
1109 && !(link & (sizeof(link) - 1))
1110 && !__get_user(UNW_PC(frame),
1111 (unsigned long *)(UNW_FP(frame)
1112 + FRAME_RETADDR_OFFSET)))
1113 {
1114 UNW_SP(frame) =
1115 UNW_FP(frame) + FRAME_RETADDR_OFFSET
1116#if FRAME_RETADDR_OFFSET < 0
1117 -
1118#else
1119 +
1120#endif
1121 sizeof(UNW_PC(frame));
1122 UNW_FP(frame) = link;
1123 return 0;
1124 }
1125 }
1126#endif
1127 return -ENXIO;
1128 }
1129 state.org = startLoc;
1130 memcpy(&state.cfa, &badCFA, sizeof(state.cfa));
1131
1132 unw_debug("\nProcess instructions\n");
1133
1134 /* process instructions
1135 * For ARC, we optimize by having blink(retAddrReg) with
1136 * the sameValue in the leaf function, so we should not check
1137 * state.regs[retAddrReg].where == Nowhere
1138 */
1139 if (!processCFI(ptr, end, pc, ptrType, &state)
1140 || state.loc > endLoc
1141/* || state.regs[retAddrReg].where == Nowhere */
1142 || state.cfa.reg >= ARRAY_SIZE(reg_info)
1143 || reg_info[state.cfa.reg].width != sizeof(unsigned long)
1144 || state.cfa.offs % sizeof(unsigned long))
1145 return -EIO;
1146
1147#ifdef UNWIND_DEBUG
1148 unw_debug("\n");
1149
1150 unw_debug("\nRegister State Based on the rules parsed from FDE:\n");
1151 for (i = 0; i < ARRAY_SIZE(state.regs); ++i) {
1152
1153 if (REG_INVALID(i))
1154 continue;
1155
1156 switch (state.regs[i].where) {
1157 case Nowhere:
1158 break;
1159 case Memory:
1160 unw_debug(" r%d: c(%lu),", i, state.regs[i].value);
1161 break;
1162 case Register:
1163 unw_debug(" r%d: r(%lu),", i, state.regs[i].value);
1164 break;
1165 case Value:
1166 unw_debug(" r%d: v(%lu),", i, state.regs[i].value);
1167 break;
1168 }
1169 }
1170
1171 unw_debug("\n");
1172#endif
1173
1174 /* update frame */
1175#ifndef CONFIG_AS_CFI_SIGNAL_FRAME
1176 if (frame->call_frame
1177 && !UNW_DEFAULT_RA(state.regs[retAddrReg], state.dataAlign))
1178 frame->call_frame = 0;
1179#endif
1180 cfa = FRAME_REG(state.cfa.reg, unsigned long) + state.cfa.offs;
1181 startLoc = min_t(unsigned long, UNW_SP(frame), cfa);
1182 endLoc = max_t(unsigned long, UNW_SP(frame), cfa);
1183 if (STACK_LIMIT(startLoc) != STACK_LIMIT(endLoc)) {
1184 startLoc = min(STACK_LIMIT(cfa), cfa);
1185 endLoc = max(STACK_LIMIT(cfa), cfa);
1186 }
1187
1188 unw_debug("\nCFA reg: 0x%lx, offset: 0x%lx => 0x%lx\n",
1189 state.cfa.reg, state.cfa.offs, cfa);
1190
1191 for (i = 0; i < ARRAY_SIZE(state.regs); ++i) {
1192 if (REG_INVALID(i)) {
1193 if (state.regs[i].where == Nowhere)
1194 continue;
1195 return -EIO;
1196 }
1197 switch (state.regs[i].where) {
1198 default:
1199 break;
1200 case Register:
1201 if (state.regs[i].value >= ARRAY_SIZE(reg_info)
1202 || REG_INVALID(state.regs[i].value)
1203 || reg_info[i].width >
1204 reg_info[state.regs[i].value].width)
1205 return -EIO;
1206 switch (reg_info[state.regs[i].value].width) {
1207 case sizeof(u8):
1208 state.regs[i].value =
1209 FRAME_REG(state.regs[i].value, const u8);
1210 break;
1211 case sizeof(u16):
1212 state.regs[i].value =
1213 FRAME_REG(state.regs[i].value, const u16);
1214 break;
1215 case sizeof(u32):
1216 state.regs[i].value =
1217 FRAME_REG(state.regs[i].value, const u32);
1218 break;
1219#ifdef CONFIG_64BIT
1220 case sizeof(u64):
1221 state.regs[i].value =
1222 FRAME_REG(state.regs[i].value, const u64);
1223 break;
1224#endif
1225 default:
1226 return -EIO;
1227 }
1228 break;
1229 }
1230 }
1231
1232 unw_debug("\nRegister state after evaluation with realtime Stack:\n");
1233 fptr = (unsigned long *)(&frame->regs);
1234 for (i = 0; i < ARRAY_SIZE(state.regs); ++i, fptr++) {
1235
1236 if (REG_INVALID(i))
1237 continue;
1238 switch (state.regs[i].where) {
1239 case Nowhere:
1240 if (reg_info[i].width != sizeof(UNW_SP(frame))
1241 || &FRAME_REG(i, __typeof__(UNW_SP(frame)))
1242 != &UNW_SP(frame))
1243 continue;
1244 UNW_SP(frame) = cfa;
1245 break;
1246 case Register:
1247 switch (reg_info[i].width) {
1248 case sizeof(u8):
1249 FRAME_REG(i, u8) = state.regs[i].value;
1250 break;
1251 case sizeof(u16):
1252 FRAME_REG(i, u16) = state.regs[i].value;
1253 break;
1254 case sizeof(u32):
1255 FRAME_REG(i, u32) = state.regs[i].value;
1256 break;
1257#ifdef CONFIG_64BIT
1258 case sizeof(u64):
1259 FRAME_REG(i, u64) = state.regs[i].value;
1260 break;
1261#endif
1262 default:
1263 return -EIO;
1264 }
1265 break;
1266 case Value:
1267 if (reg_info[i].width != sizeof(unsigned long))
1268 return -EIO;
1269 FRAME_REG(i, unsigned long) = cfa + state.regs[i].value
1270 * state.dataAlign;
1271 break;
1272 case Memory:
1273 addr = cfa + state.regs[i].value * state.dataAlign;
1274
1275 if ((state.regs[i].value * state.dataAlign)
1276 % sizeof(unsigned long)
1277 || addr < startLoc
1278 || addr + sizeof(unsigned long) < addr
1279 || addr + sizeof(unsigned long) > endLoc)
1280 return -EIO;
1281
1282 switch (reg_info[i].width) {
1283 case sizeof(u8):
1284 __get_user(FRAME_REG(i, u8),
1285 (u8 __user *)addr);
1286 break;
1287 case sizeof(u16):
1288 __get_user(FRAME_REG(i, u16),
1289 (u16 __user *)addr);
1290 break;
1291 case sizeof(u32):
1292 __get_user(FRAME_REG(i, u32),
1293 (u32 __user *)addr);
1294 break;
1295#ifdef CONFIG_64BIT
1296 case sizeof(u64):
1297 __get_user(FRAME_REG(i, u64),
1298 (u64 __user *)addr);
1299 break;
1300#endif
1301 default:
1302 return -EIO;
1303 }
1304
1305 break;
1306 }
1307 unw_debug("r%d: 0x%lx ", i, *fptr);
1308 }
1309
1310 return 0;
1311#undef FRAME_REG
1312}
1313EXPORT_SYMBOL(arc_unwind);