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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// 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
25extern 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
31int dbg_unw;
32#define unw_debug(fmt, ...) \
33do { \
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 % sizeof_field(struct unwind_frame_info, f)) \
46 + offsetof(struct unwind_frame_info, f) \
47 / sizeof_field(struct unwind_frame_info, f), \
48 sizeof_field(struct unwind_frame_info, f) \
49 }
50#define PTREGS_INFO(f) EXTRA_INFO(regs.f)
51
52static const struct {
53 unsigned offs:BITS_PER_LONG / 2;
54 unsigned width:BITS_PER_LONG / 2;
55} reg_info[] = {
56UNW_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
113typedef unsigned long uleb128_t;
114typedef signed long sleb128_t;
115
116static 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
129struct unwind_item {
130 enum item_location {
131 Nowhere,
132 Memory,
133 Register,
134 Value
135 } where;
136 uleb128_t value;
137};
138
139struct 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
154static const struct cfa badCFA = { ARRAY_SIZE(reg_info), 1 };
155
156static 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
170static unsigned long read_pointer(const u8 **pLoc,
171 const void *end, signed ptrType);
172static 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 */
179static void *__init unw_hdr_alloc_early(unsigned long sz)
180{
181 return memblock_alloc_from(sz, sizeof(unsigned int), MAX_DMA_ADDRESS);
182}
183
184static void init_unwind_table(struct unwind_table *table, const char *name,
185 const void *core_start, unsigned long core_size,
186 const void *init_start, unsigned long init_size,
187 const void *table_start, unsigned long table_size,
188 const u8 *header_start, unsigned long header_size)
189{
190 table->core.pc = (unsigned long)core_start;
191 table->core.range = core_size;
192 table->init.pc = (unsigned long)init_start;
193 table->init.range = init_size;
194 table->address = table_start;
195 table->size = table_size;
196 /* To avoid the pointer addition with NULL pointer.*/
197 if (header_start != NULL) {
198 const u8 *ptr = header_start + 4;
199 const u8 *end = header_start + header_size;
200 /* See if the linker provided table looks valid. */
201 if (header_size <= 4
202 || header_start[0] != 1
203 || (void *)read_pointer(&ptr, end, header_start[1])
204 != table_start
205 || header_start[2] == DW_EH_PE_omit
206 || read_pointer(&ptr, end, header_start[2]) <= 0
207 || header_start[3] == DW_EH_PE_omit)
208 header_start = NULL;
209 }
210 table->hdrsz = header_size;
211 smp_wmb();
212 table->header = header_start;
213 table->link = NULL;
214 table->name = name;
215}
216
217void __init arc_unwind_init(void)
218{
219 init_unwind_table(&root_table, "kernel", _text, _end - _text, NULL, 0,
220 __start_unwind, __end_unwind - __start_unwind,
221 NULL, 0);
222 /*__start_unwind_hdr, __end_unwind_hdr - __start_unwind_hdr);*/
223
224 init_unwind_hdr(&root_table, unw_hdr_alloc_early);
225}
226
227static const u32 bad_cie, not_fde;
228static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *);
229static const u32 *__cie_for_fde(const u32 *fde);
230static signed fde_pointer_type(const u32 *cie);
231
232struct eh_frame_hdr_table_entry {
233 unsigned long start, fde;
234};
235
236static int cmp_eh_frame_hdr_table_entries(const void *p1, const void *p2)
237{
238 const struct eh_frame_hdr_table_entry *e1 = p1;
239 const struct eh_frame_hdr_table_entry *e2 = p2;
240
241 return (e1->start > e2->start) - (e1->start < e2->start);
242}
243
244static void swap_eh_frame_hdr_table_entries(void *p1, void *p2, int size)
245{
246 struct eh_frame_hdr_table_entry *e1 = p1;
247 struct eh_frame_hdr_table_entry *e2 = p2;
248 unsigned long v;
249
250 v = e1->start;
251 e1->start = e2->start;
252 e2->start = v;
253 v = e1->fde;
254 e1->fde = e2->fde;
255 e2->fde = v;
256}
257
258static void init_unwind_hdr(struct unwind_table *table,
259 void *(*alloc) (unsigned long))
260{
261 const u8 *ptr;
262 unsigned long tableSize = table->size, hdrSize;
263 unsigned int n;
264 const u32 *fde;
265 struct {
266 u8 version;
267 u8 eh_frame_ptr_enc;
268 u8 fde_count_enc;
269 u8 table_enc;
270 unsigned long eh_frame_ptr;
271 unsigned int fde_count;
272 struct eh_frame_hdr_table_entry table[];
273 } __attribute__ ((__packed__)) *header;
274
275 if (table->header)
276 return;
277
278 if (table->hdrsz)
279 pr_warn(".eh_frame_hdr for '%s' present but unusable\n",
280 table->name);
281
282 if (tableSize & (sizeof(*fde) - 1))
283 return;
284
285 for (fde = table->address, n = 0;
286 tableSize > sizeof(*fde) && tableSize - sizeof(*fde) >= *fde;
287 tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) {
288 const u32 *cie = cie_for_fde(fde, table);
289 signed ptrType;
290
291 if (cie == ¬_fde)
292 continue;
293 if (cie == NULL || cie == &bad_cie)
294 goto ret_err;
295 ptrType = fde_pointer_type(cie);
296 if (ptrType < 0)
297 goto ret_err;
298
299 ptr = (const u8 *)(fde + 2);
300 if (!read_pointer(&ptr, (const u8 *)(fde + 1) + *fde,
301 ptrType)) {
302 /* FIXME_Rajesh We have 4 instances of null addresses
303 * instead of the initial loc addr
304 * return;
305 */
306 WARN(1, "unwinder: FDE->initial_location NULL %p\n",
307 (const u8 *)(fde + 1) + *fde);
308 }
309 ++n;
310 }
311
312 if (tableSize || !n)
313 goto ret_err;
314
315 hdrSize = 4 + sizeof(unsigned long) + sizeof(unsigned int)
316 + 2 * n * sizeof(unsigned long);
317
318 header = alloc(hdrSize);
319 if (!header)
320 goto ret_err;
321
322 header->version = 1;
323 header->eh_frame_ptr_enc = DW_EH_PE_abs | DW_EH_PE_native;
324 header->fde_count_enc = DW_EH_PE_abs | DW_EH_PE_data4;
325 header->table_enc = DW_EH_PE_abs | DW_EH_PE_native;
326 put_unaligned((unsigned long)table->address, &header->eh_frame_ptr);
327 BUILD_BUG_ON(offsetof(typeof(*header), fde_count)
328 % __alignof(typeof(header->fde_count)));
329 header->fde_count = n;
330
331 BUILD_BUG_ON(offsetof(typeof(*header), table)
332 % __alignof(typeof(*header->table)));
333 for (fde = table->address, tableSize = table->size, n = 0;
334 tableSize;
335 tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) {
336 const u32 *cie = __cie_for_fde(fde);
337
338 if (fde[1] == CIE_ID)
339 continue; /* this is a CIE */
340 ptr = (const u8 *)(fde + 2);
341 header->table[n].start = read_pointer(&ptr,
342 (const u8 *)(fde + 1) +
343 *fde,
344 fde_pointer_type(cie));
345 header->table[n].fde = (unsigned long)fde;
346 ++n;
347 }
348 WARN_ON(n != header->fde_count);
349
350 sort(header->table,
351 n,
352 sizeof(*header->table),
353 cmp_eh_frame_hdr_table_entries, swap_eh_frame_hdr_table_entries);
354
355 table->hdrsz = hdrSize;
356 smp_wmb();
357 table->header = (const void *)header;
358 return;
359
360ret_err:
361 panic("Attention !!! Dwarf FDE parsing errors\n");
362}
363
364#ifdef CONFIG_MODULES
365static void *unw_hdr_alloc(unsigned long sz)
366{
367 return kmalloc(sz, GFP_KERNEL);
368}
369
370static struct unwind_table *last_table;
371
372/* Must be called with module_mutex held. */
373void *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
406struct unlink_table_info {
407 struct unwind_table *table;
408 int init_only;
409};
410
411static 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. */
437void 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
461static uleb128_t get_uleb128(const u8 **pcur, const u8 *end)
462{
463 const u8 *cur = *pcur;
464 uleb128_t value;
465 unsigned int 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
482static sleb128_t get_sleb128(const u8 **pcur, const u8 *end)
483{
484 const u8 *cur = *pcur;
485 sleb128_t value;
486 unsigned int 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
505static 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
514static 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 ¬_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
537static 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 fallthrough;
577 case DW_EH_PE_native:
578 if (end < (const void *)(ptr.pul + 1))
579 return 0;
580 value = get_unaligned((unsigned long *)ptr.pul++);
581 break;
582 case DW_EH_PE_leb128:
583 BUILD_BUG_ON(sizeof(uleb128_t) > sizeof(value));
584 value = ptrType & DW_EH_PE_signed ? get_sleb128(&ptr.p8, end)
585 : get_uleb128(&ptr.p8, end);
586 if ((const void *)ptr.p8 > end)
587 return 0;
588 break;
589 default:
590 return 0;
591 }
592 switch (ptrType & DW_EH_PE_ADJUST) {
593 case DW_EH_PE_abs:
594 break;
595 case DW_EH_PE_pcrel:
596 value += (unsigned long)*pLoc;
597 break;
598 default:
599 return 0;
600 }
601 if ((ptrType & DW_EH_PE_indirect)
602 && __get_user(value, (unsigned long __user *)value))
603 return 0;
604 *pLoc = ptr.p8;
605
606 return value;
607}
608
609static signed fde_pointer_type(const u32 *cie)
610{
611 const u8 *ptr = (const u8 *)(cie + 2);
612 unsigned int version = *ptr;
613
614 if (*++ptr) {
615 const char *aug;
616 const u8 *end = (const u8 *)(cie + 1) + *cie;
617 uleb128_t len;
618
619 /* check if augmentation size is first (and thus present) */
620 if (*ptr != 'z')
621 return -1;
622
623 /* check if augmentation string is nul-terminated */
624 aug = (const void *)ptr;
625 ptr = memchr(aug, 0, end - ptr);
626 if (ptr == NULL)
627 return -1;
628
629 ++ptr; /* skip terminator */
630 get_uleb128(&ptr, end); /* skip code alignment */
631 get_sleb128(&ptr, end); /* skip data alignment */
632 /* skip return address column */
633 version <= 1 ? (void) ++ptr : (void)get_uleb128(&ptr, end);
634 len = get_uleb128(&ptr, end); /* augmentation length */
635
636 if (ptr + len < ptr || ptr + len > end)
637 return -1;
638
639 end = ptr + len;
640 while (*++aug) {
641 if (ptr >= end)
642 return -1;
643 switch (*aug) {
644 case 'L':
645 ++ptr;
646 break;
647 case 'P':{
648 signed ptrType = *ptr++;
649
650 if (!read_pointer(&ptr, end, ptrType)
651 || ptr > end)
652 return -1;
653 }
654 break;
655 case 'R':
656 return *ptr;
657 default:
658 return -1;
659 }
660 }
661 }
662 return DW_EH_PE_native | DW_EH_PE_abs;
663}
664
665static int advance_loc(unsigned long delta, struct unwind_state *state)
666{
667 state->loc += delta * state->codeAlign;
668
669 /* FIXME_Rajesh: Probably we are defining for the initial range as well;
670 return delta > 0;
671 */
672 unw_debug("delta %3lu => loc 0x%lx: ", delta, state->loc);
673 return 1;
674}
675
676static void set_rule(uleb128_t reg, enum item_location where, uleb128_t value,
677 struct unwind_state *state)
678{
679 if (reg < ARRAY_SIZE(state->regs)) {
680 state->regs[reg].where = where;
681 state->regs[reg].value = value;
682
683#ifdef UNWIND_DEBUG
684 unw_debug("r%lu: ", reg);
685 switch (where) {
686 case Nowhere:
687 unw_debug("s ");
688 break;
689 case Memory:
690 unw_debug("c(%lu) ", value);
691 break;
692 case Register:
693 unw_debug("r(%lu) ", value);
694 break;
695 case Value:
696 unw_debug("v(%lu) ", value);
697 break;
698 default:
699 break;
700 }
701#endif
702 }
703}
704
705static int processCFI(const u8 *start, const u8 *end, unsigned long targetLoc,
706 signed ptrType, struct unwind_state *state)
707{
708 union {
709 const u8 *p8;
710 const u16 *p16;
711 const u32 *p32;
712 } ptr;
713 int result = 1;
714 u8 opcode;
715
716 if (start != state->cieStart) {
717 state->loc = state->org;
718 result =
719 processCFI(state->cieStart, state->cieEnd, 0, ptrType,
720 state);
721 if (targetLoc == 0 && state->label == NULL)
722 return result;
723 }
724 for (ptr.p8 = start; result && ptr.p8 < end;) {
725 switch (*ptr.p8 >> 6) {
726 uleb128_t value;
727
728 case 0:
729 opcode = *ptr.p8++;
730
731 switch (opcode) {
732 case DW_CFA_nop:
733 unw_debug("cfa nop ");
734 break;
735 case DW_CFA_set_loc:
736 state->loc = read_pointer(&ptr.p8, end,
737 ptrType);
738 if (state->loc == 0)
739 result = 0;
740 unw_debug("cfa_set_loc: 0x%lx ", state->loc);
741 break;
742 case DW_CFA_advance_loc1:
743 unw_debug("\ncfa advance loc1:");
744 result = ptr.p8 < end
745 && advance_loc(*ptr.p8++, state);
746 break;
747 case DW_CFA_advance_loc2:
748 value = *ptr.p8++;
749 value += *ptr.p8++ << 8;
750 unw_debug("\ncfa advance loc2:");
751 result = ptr.p8 <= end + 2
752 /* && advance_loc(*ptr.p16++, state); */
753 && advance_loc(value, state);
754 break;
755 case DW_CFA_advance_loc4:
756 unw_debug("\ncfa advance loc4:");
757 result = ptr.p8 <= end + 4
758 && advance_loc(*ptr.p32++, state);
759 break;
760 case DW_CFA_offset_extended:
761 value = get_uleb128(&ptr.p8, end);
762 unw_debug("cfa_offset_extended: ");
763 set_rule(value, Memory,
764 get_uleb128(&ptr.p8, end), state);
765 break;
766 case DW_CFA_val_offset:
767 value = get_uleb128(&ptr.p8, end);
768 set_rule(value, Value,
769 get_uleb128(&ptr.p8, end), state);
770 break;
771 case DW_CFA_offset_extended_sf:
772 value = get_uleb128(&ptr.p8, end);
773 set_rule(value, Memory,
774 get_sleb128(&ptr.p8, end), state);
775 break;
776 case DW_CFA_val_offset_sf:
777 value = get_uleb128(&ptr.p8, end);
778 set_rule(value, Value,
779 get_sleb128(&ptr.p8, end), state);
780 break;
781 case DW_CFA_restore_extended:
782 unw_debug("cfa_restore_extended: ");
783 case DW_CFA_undefined:
784 unw_debug("cfa_undefined: ");
785 case DW_CFA_same_value:
786 unw_debug("cfa_same_value: ");
787 set_rule(get_uleb128(&ptr.p8, end), Nowhere, 0,
788 state);
789 break;
790 case DW_CFA_register:
791 unw_debug("cfa_register: ");
792 value = get_uleb128(&ptr.p8, end);
793 set_rule(value,
794 Register,
795 get_uleb128(&ptr.p8, end), state);
796 break;
797 case DW_CFA_remember_state:
798 unw_debug("cfa_remember_state: ");
799 if (ptr.p8 == state->label) {
800 state->label = NULL;
801 return 1;
802 }
803 if (state->stackDepth >= MAX_STACK_DEPTH)
804 return 0;
805 state->stack[state->stackDepth++] = ptr.p8;
806 break;
807 case DW_CFA_restore_state:
808 unw_debug("cfa_restore_state: ");
809 if (state->stackDepth) {
810 const uleb128_t loc = state->loc;
811 const u8 *label = state->label;
812
813 state->label =
814 state->stack[state->stackDepth - 1];
815 memcpy(&state->cfa, &badCFA,
816 sizeof(state->cfa));
817 memset(state->regs, 0,
818 sizeof(state->regs));
819 state->stackDepth = 0;
820 result =
821 processCFI(start, end, 0, ptrType,
822 state);
823 state->loc = loc;
824 state->label = label;
825 } else
826 return 0;
827 break;
828 case DW_CFA_def_cfa:
829 state->cfa.reg = get_uleb128(&ptr.p8, end);
830 unw_debug("cfa_def_cfa: r%lu ", state->cfa.reg);
831 fallthrough;
832 case DW_CFA_def_cfa_offset:
833 state->cfa.offs = get_uleb128(&ptr.p8, end);
834 unw_debug("cfa_def_cfa_offset: 0x%lx ",
835 state->cfa.offs);
836 break;
837 case DW_CFA_def_cfa_sf:
838 state->cfa.reg = get_uleb128(&ptr.p8, end);
839 fallthrough;
840 case DW_CFA_def_cfa_offset_sf:
841 state->cfa.offs = get_sleb128(&ptr.p8, end)
842 * state->dataAlign;
843 break;
844 case DW_CFA_def_cfa_register:
845 unw_debug("cfa_def_cfa_register: ");
846 state->cfa.reg = get_uleb128(&ptr.p8, end);
847 break;
848 /*todo case DW_CFA_def_cfa_expression: */
849 /*todo case DW_CFA_expression: */
850 /*todo case DW_CFA_val_expression: */
851 case DW_CFA_GNU_args_size:
852 get_uleb128(&ptr.p8, end);
853 break;
854 case DW_CFA_GNU_negative_offset_extended:
855 value = get_uleb128(&ptr.p8, end);
856 set_rule(value,
857 Memory,
858 (uleb128_t) 0 - get_uleb128(&ptr.p8,
859 end),
860 state);
861 break;
862 case DW_CFA_GNU_window_save:
863 default:
864 unw_debug("UNKNOWN OPCODE 0x%x\n", opcode);
865 result = 0;
866 break;
867 }
868 break;
869 case 1:
870 unw_debug("\ncfa_adv_loc: ");
871 result = advance_loc(*ptr.p8++ & 0x3f, state);
872 break;
873 case 2:
874 unw_debug("cfa_offset: ");
875 value = *ptr.p8++ & 0x3f;
876 set_rule(value, Memory, get_uleb128(&ptr.p8, end),
877 state);
878 break;
879 case 3:
880 unw_debug("cfa_restore: ");
881 set_rule(*ptr.p8++ & 0x3f, Nowhere, 0, state);
882 break;
883 }
884
885 if (ptr.p8 > end)
886 result = 0;
887 if (result && targetLoc != 0 && targetLoc < state->loc)
888 return 1;
889 }
890
891 return result && ptr.p8 == end && (targetLoc == 0 || (
892 /*todo While in theory this should apply, gcc in practice omits
893 everything past the function prolog, and hence the location
894 never reaches the end of the function.
895 targetLoc < state->loc && */ state->label == NULL));
896}
897
898/* Unwind to previous to frame. Returns 0 if successful, negative
899 * number in case of an error. */
900int arc_unwind(struct unwind_frame_info *frame)
901{
902#define FRAME_REG(r, t) (((t *)frame)[reg_info[r].offs])
903 const u32 *fde = NULL, *cie = NULL;
904 const u8 *ptr = NULL, *end = NULL;
905 unsigned long pc = UNW_PC(frame) - frame->call_frame;
906 unsigned long startLoc = 0, endLoc = 0, cfa;
907 unsigned int i;
908 signed ptrType = -1;
909 uleb128_t retAddrReg = 0;
910 const struct unwind_table *table;
911 struct unwind_state state;
912 unsigned long *fptr;
913 unsigned long addr;
914
915 unw_debug("\n\nUNWIND FRAME:\n");
916 unw_debug("PC: 0x%lx BLINK: 0x%lx, SP: 0x%lx, FP: 0x%x\n",
917 UNW_PC(frame), UNW_BLINK(frame), UNW_SP(frame),
918 UNW_FP(frame));
919
920 if (UNW_PC(frame) == 0)
921 return -EINVAL;
922
923#ifdef UNWIND_DEBUG
924 {
925 unsigned long *sptr = (unsigned long *)UNW_SP(frame);
926 unw_debug("\nStack Dump:\n");
927 for (i = 0; i < 20; i++, sptr++)
928 unw_debug("0x%p: 0x%lx\n", sptr, *sptr);
929 unw_debug("\n");
930 }
931#endif
932
933 table = find_table(pc);
934 if (table != NULL
935 && !(table->size & (sizeof(*fde) - 1))) {
936 const u8 *hdr = table->header;
937 unsigned long tableSize;
938
939 smp_rmb();
940 if (hdr && hdr[0] == 1) {
941 switch (hdr[3] & DW_EH_PE_FORM) {
942 case DW_EH_PE_native:
943 tableSize = sizeof(unsigned long);
944 break;
945 case DW_EH_PE_data2:
946 tableSize = 2;
947 break;
948 case DW_EH_PE_data4:
949 tableSize = 4;
950 break;
951 case DW_EH_PE_data8:
952 tableSize = 8;
953 break;
954 default:
955 tableSize = 0;
956 break;
957 }
958 ptr = hdr + 4;
959 end = hdr + table->hdrsz;
960 if (tableSize && read_pointer(&ptr, end, hdr[1])
961 == (unsigned long)table->address
962 && (i = read_pointer(&ptr, end, hdr[2])) > 0
963 && i == (end - ptr) / (2 * tableSize)
964 && !((end - ptr) % (2 * tableSize))) {
965 do {
966 const u8 *cur =
967 ptr + (i / 2) * (2 * tableSize);
968
969 startLoc = read_pointer(&cur,
970 cur + tableSize,
971 hdr[3]);
972 if (pc < startLoc)
973 i /= 2;
974 else {
975 ptr = cur - tableSize;
976 i = (i + 1) / 2;
977 }
978 } while (startLoc && i > 1);
979 if (i == 1
980 && (startLoc = read_pointer(&ptr,
981 ptr + tableSize,
982 hdr[3])) != 0
983 && pc >= startLoc)
984 fde = (void *)read_pointer(&ptr,
985 ptr +
986 tableSize,
987 hdr[3]);
988 }
989 }
990
991 if (fde != NULL) {
992 cie = cie_for_fde(fde, table);
993 ptr = (const u8 *)(fde + 2);
994 if (cie != NULL
995 && cie != &bad_cie
996 && cie != ¬_fde
997 && (ptrType = fde_pointer_type(cie)) >= 0
998 && read_pointer(&ptr,
999 (const u8 *)(fde + 1) + *fde,
1000 ptrType) == startLoc) {
1001 if (!(ptrType & DW_EH_PE_indirect))
1002 ptrType &=
1003 DW_EH_PE_FORM | DW_EH_PE_signed;
1004 endLoc =
1005 startLoc + read_pointer(&ptr,
1006 (const u8 *)(fde +
1007 1) +
1008 *fde, ptrType);
1009 if (pc >= endLoc) {
1010 fde = NULL;
1011 cie = NULL;
1012 }
1013 } else {
1014 fde = NULL;
1015 cie = NULL;
1016 }
1017 }
1018 }
1019 if (cie != NULL) {
1020 memset(&state, 0, sizeof(state));
1021 state.cieEnd = ptr; /* keep here temporarily */
1022 ptr = (const u8 *)(cie + 2);
1023 end = (const u8 *)(cie + 1) + *cie;
1024 frame->call_frame = 1;
1025 if (*++ptr) {
1026 /* check if augmentation size is first (thus present) */
1027 if (*ptr == 'z') {
1028 while (++ptr < end && *ptr) {
1029 switch (*ptr) {
1030 /* chk for ignorable or already handled
1031 * nul-terminated augmentation string */
1032 case 'L':
1033 case 'P':
1034 case 'R':
1035 continue;
1036 case 'S':
1037 frame->call_frame = 0;
1038 continue;
1039 default:
1040 break;
1041 }
1042 break;
1043 }
1044 }
1045 if (ptr >= end || *ptr)
1046 cie = NULL;
1047 }
1048 ++ptr;
1049 }
1050 if (cie != NULL) {
1051 /* get code alignment factor */
1052 state.codeAlign = get_uleb128(&ptr, end);
1053 /* get data alignment factor */
1054 state.dataAlign = get_sleb128(&ptr, end);
1055 if (state.codeAlign == 0 || state.dataAlign == 0 || ptr >= end)
1056 cie = NULL;
1057 else {
1058 retAddrReg =
1059 state.version <= 1 ? *ptr++ : get_uleb128(&ptr,
1060 end);
1061 unw_debug("CIE Frame Info:\n");
1062 unw_debug("return Address register 0x%lx\n",
1063 retAddrReg);
1064 unw_debug("data Align: %ld\n", state.dataAlign);
1065 unw_debug("code Align: %lu\n", state.codeAlign);
1066 /* skip augmentation */
1067 if (((const char *)(cie + 2))[1] == 'z') {
1068 uleb128_t augSize = get_uleb128(&ptr, end);
1069
1070 ptr += augSize;
1071 }
1072 if (ptr > end || retAddrReg >= ARRAY_SIZE(reg_info)
1073 || REG_INVALID(retAddrReg)
1074 || reg_info[retAddrReg].width !=
1075 sizeof(unsigned long))
1076 cie = NULL;
1077 }
1078 }
1079 if (cie != NULL) {
1080 state.cieStart = ptr;
1081 ptr = state.cieEnd;
1082 state.cieEnd = end;
1083 end = (const u8 *)(fde + 1) + *fde;
1084 /* skip augmentation */
1085 if (((const char *)(cie + 2))[1] == 'z') {
1086 uleb128_t augSize = get_uleb128(&ptr, end);
1087
1088 if ((ptr += augSize) > end)
1089 fde = NULL;
1090 }
1091 }
1092 if (cie == NULL || fde == NULL) {
1093#ifdef CONFIG_FRAME_POINTER
1094 unsigned long top, bottom;
1095
1096 top = STACK_TOP_UNW(frame->task);
1097 bottom = STACK_BOTTOM_UNW(frame->task);
1098#if FRAME_RETADDR_OFFSET < 0
1099 if (UNW_SP(frame) < top && UNW_FP(frame) <= UNW_SP(frame)
1100 && bottom < UNW_FP(frame)
1101#else
1102 if (UNW_SP(frame) > top && UNW_FP(frame) >= UNW_SP(frame)
1103 && bottom > UNW_FP(frame)
1104#endif
1105 && !((UNW_SP(frame) | UNW_FP(frame))
1106 & (sizeof(unsigned long) - 1))) {
1107 unsigned long link;
1108
1109 if (!__get_user(link, (unsigned long *)
1110 (UNW_FP(frame) + FRAME_LINK_OFFSET))
1111#if FRAME_RETADDR_OFFSET < 0
1112 && link > bottom && link < UNW_FP(frame)
1113#else
1114 && link > UNW_FP(frame) && link < bottom
1115#endif
1116 && !(link & (sizeof(link) - 1))
1117 && !__get_user(UNW_PC(frame),
1118 (unsigned long *)(UNW_FP(frame)
1119 + FRAME_RETADDR_OFFSET)))
1120 {
1121 UNW_SP(frame) =
1122 UNW_FP(frame) + FRAME_RETADDR_OFFSET
1123#if FRAME_RETADDR_OFFSET < 0
1124 -
1125#else
1126 +
1127#endif
1128 sizeof(UNW_PC(frame));
1129 UNW_FP(frame) = link;
1130 return 0;
1131 }
1132 }
1133#endif
1134 return -ENXIO;
1135 }
1136 state.org = startLoc;
1137 memcpy(&state.cfa, &badCFA, sizeof(state.cfa));
1138
1139 unw_debug("\nProcess instructions\n");
1140
1141 /* process instructions
1142 * For ARC, we optimize by having blink(retAddrReg) with
1143 * the sameValue in the leaf function, so we should not check
1144 * state.regs[retAddrReg].where == Nowhere
1145 */
1146 if (!processCFI(ptr, end, pc, ptrType, &state)
1147 || state.loc > endLoc
1148/* || state.regs[retAddrReg].where == Nowhere */
1149 || state.cfa.reg >= ARRAY_SIZE(reg_info)
1150 || reg_info[state.cfa.reg].width != sizeof(unsigned long)
1151 || state.cfa.offs % sizeof(unsigned long))
1152 return -EIO;
1153
1154#ifdef UNWIND_DEBUG
1155 unw_debug("\n");
1156
1157 unw_debug("\nRegister State Based on the rules parsed from FDE:\n");
1158 for (i = 0; i < ARRAY_SIZE(state.regs); ++i) {
1159
1160 if (REG_INVALID(i))
1161 continue;
1162
1163 switch (state.regs[i].where) {
1164 case Nowhere:
1165 break;
1166 case Memory:
1167 unw_debug(" r%d: c(%lu),", i, state.regs[i].value);
1168 break;
1169 case Register:
1170 unw_debug(" r%d: r(%lu),", i, state.regs[i].value);
1171 break;
1172 case Value:
1173 unw_debug(" r%d: v(%lu),", i, state.regs[i].value);
1174 break;
1175 }
1176 }
1177
1178 unw_debug("\n");
1179#endif
1180
1181 /* update frame */
1182 if (frame->call_frame
1183 && !UNW_DEFAULT_RA(state.regs[retAddrReg], state.dataAlign))
1184 frame->call_frame = 0;
1185 cfa = FRAME_REG(state.cfa.reg, unsigned long) + state.cfa.offs;
1186 startLoc = min_t(unsigned long, UNW_SP(frame), cfa);
1187 endLoc = max_t(unsigned long, UNW_SP(frame), cfa);
1188 if (STACK_LIMIT(startLoc) != STACK_LIMIT(endLoc)) {
1189 startLoc = min(STACK_LIMIT(cfa), cfa);
1190 endLoc = max(STACK_LIMIT(cfa), cfa);
1191 }
1192
1193 unw_debug("\nCFA reg: 0x%lx, offset: 0x%lx => 0x%lx\n",
1194 state.cfa.reg, state.cfa.offs, cfa);
1195
1196 for (i = 0; i < ARRAY_SIZE(state.regs); ++i) {
1197 if (REG_INVALID(i)) {
1198 if (state.regs[i].where == Nowhere)
1199 continue;
1200 return -EIO;
1201 }
1202 switch (state.regs[i].where) {
1203 default:
1204 break;
1205 case Register:
1206 if (state.regs[i].value >= ARRAY_SIZE(reg_info)
1207 || REG_INVALID(state.regs[i].value)
1208 || reg_info[i].width >
1209 reg_info[state.regs[i].value].width)
1210 return -EIO;
1211 switch (reg_info[state.regs[i].value].width) {
1212 case sizeof(u8):
1213 state.regs[i].value =
1214 FRAME_REG(state.regs[i].value, const u8);
1215 break;
1216 case sizeof(u16):
1217 state.regs[i].value =
1218 FRAME_REG(state.regs[i].value, const u16);
1219 break;
1220 case sizeof(u32):
1221 state.regs[i].value =
1222 FRAME_REG(state.regs[i].value, const u32);
1223 break;
1224#ifdef CONFIG_64BIT
1225 case sizeof(u64):
1226 state.regs[i].value =
1227 FRAME_REG(state.regs[i].value, const u64);
1228 break;
1229#endif
1230 default:
1231 return -EIO;
1232 }
1233 break;
1234 }
1235 }
1236
1237 unw_debug("\nRegister state after evaluation with realtime Stack:\n");
1238 fptr = (unsigned long *)(&frame->regs);
1239 for (i = 0; i < ARRAY_SIZE(state.regs); ++i, fptr++) {
1240
1241 if (REG_INVALID(i))
1242 continue;
1243 switch (state.regs[i].where) {
1244 case Nowhere:
1245 if (reg_info[i].width != sizeof(UNW_SP(frame))
1246 || &FRAME_REG(i, __typeof__(UNW_SP(frame)))
1247 != &UNW_SP(frame))
1248 continue;
1249 UNW_SP(frame) = cfa;
1250 break;
1251 case Register:
1252 switch (reg_info[i].width) {
1253 case sizeof(u8):
1254 FRAME_REG(i, u8) = state.regs[i].value;
1255 break;
1256 case sizeof(u16):
1257 FRAME_REG(i, u16) = state.regs[i].value;
1258 break;
1259 case sizeof(u32):
1260 FRAME_REG(i, u32) = state.regs[i].value;
1261 break;
1262#ifdef CONFIG_64BIT
1263 case sizeof(u64):
1264 FRAME_REG(i, u64) = state.regs[i].value;
1265 break;
1266#endif
1267 default:
1268 return -EIO;
1269 }
1270 break;
1271 case Value:
1272 if (reg_info[i].width != sizeof(unsigned long))
1273 return -EIO;
1274 FRAME_REG(i, unsigned long) = cfa + state.regs[i].value
1275 * state.dataAlign;
1276 break;
1277 case Memory:
1278 addr = cfa + state.regs[i].value * state.dataAlign;
1279
1280 if ((state.regs[i].value * state.dataAlign)
1281 % sizeof(unsigned long)
1282 || addr < startLoc
1283 || addr + sizeof(unsigned long) < addr
1284 || addr + sizeof(unsigned long) > endLoc)
1285 return -EIO;
1286
1287 switch (reg_info[i].width) {
1288 case sizeof(u8):
1289 __get_user(FRAME_REG(i, u8),
1290 (u8 __user *)addr);
1291 break;
1292 case sizeof(u16):
1293 __get_user(FRAME_REG(i, u16),
1294 (u16 __user *)addr);
1295 break;
1296 case sizeof(u32):
1297 __get_user(FRAME_REG(i, u32),
1298 (u32 __user *)addr);
1299 break;
1300#ifdef CONFIG_64BIT
1301 case sizeof(u64):
1302 __get_user(FRAME_REG(i, u64),
1303 (u64 __user *)addr);
1304 break;
1305#endif
1306 default:
1307 return -EIO;
1308 }
1309
1310 break;
1311 }
1312 unw_debug("r%d: 0x%lx ", i, *fptr);
1313 }
1314
1315 return 0;
1316#undef FRAME_REG
1317}
1318EXPORT_SYMBOL(arc_unwind);