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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
4 * Copyright (C) 2002-2006 Novell, Inc.
5 * Jan Beulich <jbeulich@novell.com>
6 *
7 * A simple API for unwinding kernel stacks. This is used for
8 * debugging and error reporting purposes. The kernel doesn't need
9 * full-blown stack unwinding with all the bells and whistles, so there
10 * is not much point in implementing the full Dwarf2 unwind API.
11 */
12
13#include <linux/sched.h>
14#include <linux/module.h>
15#include <linux/memblock.h>
16#include <linux/sort.h>
17#include <linux/slab.h>
18#include <linux/stop_machine.h>
19#include <linux/uaccess.h>
20#include <linux/ptrace.h>
21#include <asm/sections.h>
22#include <asm/unaligned.h>
23#include <asm/unwind.h>
24
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
249 swap(e1->start, e2->start);
250 swap(e1->fde, e2->fde);
251}
252
253static void init_unwind_hdr(struct unwind_table *table,
254 void *(*alloc) (unsigned long))
255{
256 const u8 *ptr;
257 unsigned long tableSize = table->size, hdrSize;
258 unsigned int n;
259 const u32 *fde;
260 struct {
261 u8 version;
262 u8 eh_frame_ptr_enc;
263 u8 fde_count_enc;
264 u8 table_enc;
265 unsigned long eh_frame_ptr;
266 unsigned int fde_count;
267 struct eh_frame_hdr_table_entry table[];
268 } __attribute__ ((__packed__)) *header;
269
270 if (table->header)
271 return;
272
273 if (table->hdrsz)
274 pr_warn(".eh_frame_hdr for '%s' present but unusable\n",
275 table->name);
276
277 if (tableSize & (sizeof(*fde) - 1))
278 return;
279
280 for (fde = table->address, n = 0;
281 tableSize > sizeof(*fde) && tableSize - sizeof(*fde) >= *fde;
282 tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) {
283 const u32 *cie = cie_for_fde(fde, table);
284 signed ptrType;
285
286 if (cie == ¬_fde)
287 continue;
288 if (cie == NULL || cie == &bad_cie)
289 goto ret_err;
290 ptrType = fde_pointer_type(cie);
291 if (ptrType < 0)
292 goto ret_err;
293
294 ptr = (const u8 *)(fde + 2);
295 if (!read_pointer(&ptr, (const u8 *)(fde + 1) + *fde,
296 ptrType)) {
297 /* FIXME_Rajesh We have 4 instances of null addresses
298 * instead of the initial loc addr
299 * return;
300 */
301 WARN(1, "unwinder: FDE->initial_location NULL %p\n",
302 (const u8 *)(fde + 1) + *fde);
303 }
304 ++n;
305 }
306
307 if (tableSize || !n)
308 goto ret_err;
309
310 hdrSize = 4 + sizeof(unsigned long) + sizeof(unsigned int)
311 + 2 * n * sizeof(unsigned long);
312
313 header = alloc(hdrSize);
314 if (!header)
315 goto ret_err;
316
317 header->version = 1;
318 header->eh_frame_ptr_enc = DW_EH_PE_abs | DW_EH_PE_native;
319 header->fde_count_enc = DW_EH_PE_abs | DW_EH_PE_data4;
320 header->table_enc = DW_EH_PE_abs | DW_EH_PE_native;
321 put_unaligned((unsigned long)table->address, &header->eh_frame_ptr);
322 BUILD_BUG_ON(offsetof(typeof(*header), fde_count)
323 % __alignof(typeof(header->fde_count)));
324 header->fde_count = n;
325
326 BUILD_BUG_ON(offsetof(typeof(*header), table)
327 % __alignof(typeof(*header->table)));
328 for (fde = table->address, tableSize = table->size, n = 0;
329 tableSize;
330 tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) {
331 const u32 *cie = __cie_for_fde(fde);
332
333 if (fde[1] == CIE_ID)
334 continue; /* this is a CIE */
335 ptr = (const u8 *)(fde + 2);
336 header->table[n].start = read_pointer(&ptr,
337 (const u8 *)(fde + 1) +
338 *fde,
339 fde_pointer_type(cie));
340 header->table[n].fde = (unsigned long)fde;
341 ++n;
342 }
343 WARN_ON(n != header->fde_count);
344
345 sort(header->table,
346 n,
347 sizeof(*header->table),
348 cmp_eh_frame_hdr_table_entries, swap_eh_frame_hdr_table_entries);
349
350 table->hdrsz = hdrSize;
351 smp_wmb();
352 table->header = (const void *)header;
353 return;
354
355ret_err:
356 panic("Attention !!! Dwarf FDE parsing errors\n");
357}
358
359#ifdef CONFIG_MODULES
360static void *unw_hdr_alloc(unsigned long sz)
361{
362 return kmalloc(sz, GFP_KERNEL);
363}
364
365static struct unwind_table *last_table;
366
367/* Must be called with module_mutex held. */
368void *unwind_add_table(struct module *module, const void *table_start,
369 unsigned long table_size)
370{
371 struct unwind_table *table;
372
373 if (table_size <= 0)
374 return NULL;
375
376 table = kmalloc(sizeof(*table), GFP_KERNEL);
377 if (!table)
378 return NULL;
379
380 init_unwind_table(table, module->name,
381 module->core_layout.base, module->core_layout.size,
382 module->init_layout.base, module->init_layout.size,
383 table_start, table_size,
384 NULL, 0);
385
386 init_unwind_hdr(table, unw_hdr_alloc);
387
388#ifdef UNWIND_DEBUG
389 unw_debug("Table added for [%s] %lx %lx\n",
390 module->name, table->core.pc, table->core.range);
391#endif
392 if (last_table)
393 last_table->link = table;
394 else
395 root_table.link = table;
396 last_table = table;
397
398 return table;
399}
400
401struct unlink_table_info {
402 struct unwind_table *table;
403 int init_only;
404};
405
406static int unlink_table(void *arg)
407{
408 struct unlink_table_info *info = arg;
409 struct unwind_table *table = info->table, *prev;
410
411 for (prev = &root_table; prev->link && prev->link != table;
412 prev = prev->link)
413 ;
414
415 if (prev->link) {
416 if (info->init_only) {
417 table->init.pc = 0;
418 table->init.range = 0;
419 info->table = NULL;
420 } else {
421 prev->link = table->link;
422 if (!prev->link)
423 last_table = prev;
424 }
425 } else
426 info->table = NULL;
427
428 return 0;
429}
430
431/* Must be called with module_mutex held. */
432void unwind_remove_table(void *handle, int init_only)
433{
434 struct unwind_table *table = handle;
435 struct unlink_table_info info;
436
437 if (!table || table == &root_table)
438 return;
439
440 if (init_only && table == last_table) {
441 table->init.pc = 0;
442 table->init.range = 0;
443 return;
444 }
445
446 info.table = table;
447 info.init_only = init_only;
448
449 unlink_table(&info); /* XXX: SMP */
450 kfree(table->header);
451 kfree(table);
452}
453
454#endif /* CONFIG_MODULES */
455
456static uleb128_t get_uleb128(const u8 **pcur, const u8 *end)
457{
458 const u8 *cur = *pcur;
459 uleb128_t value;
460 unsigned int shift;
461
462 for (shift = 0, value = 0; cur < end; shift += 7) {
463 if (shift + 7 > 8 * sizeof(value)
464 && (*cur & 0x7fU) >= (1U << (8 * sizeof(value) - shift))) {
465 cur = end + 1;
466 break;
467 }
468 value |= (uleb128_t) (*cur & 0x7f) << shift;
469 if (!(*cur++ & 0x80))
470 break;
471 }
472 *pcur = cur;
473
474 return value;
475}
476
477static sleb128_t get_sleb128(const u8 **pcur, const u8 *end)
478{
479 const u8 *cur = *pcur;
480 sleb128_t value;
481 unsigned int shift;
482
483 for (shift = 0, value = 0; cur < end; shift += 7) {
484 if (shift + 7 > 8 * sizeof(value)
485 && (*cur & 0x7fU) >= (1U << (8 * sizeof(value) - shift))) {
486 cur = end + 1;
487 break;
488 }
489 value |= (sleb128_t) (*cur & 0x7f) << shift;
490 if (!(*cur & 0x80)) {
491 value |= -(*cur++ & 0x40) << shift;
492 break;
493 }
494 }
495 *pcur = cur;
496
497 return value;
498}
499
500static const u32 *__cie_for_fde(const u32 *fde)
501{
502 const u32 *cie;
503
504 cie = fde + 1 - fde[1] / sizeof(*fde);
505
506 return cie;
507}
508
509static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *table)
510{
511 const u32 *cie;
512
513 if (!*fde || (*fde & (sizeof(*fde) - 1)))
514 return &bad_cie;
515
516 if (fde[1] == CIE_ID)
517 return ¬_fde; /* this is a CIE */
518
519 if ((fde[1] & (sizeof(*fde) - 1)))
520/* || fde[1] > (unsigned long)(fde + 1) - (unsigned long)table->address) */
521 return NULL; /* this is not a valid FDE */
522
523 cie = __cie_for_fde(fde);
524
525 if (*cie <= sizeof(*cie) + 4 || *cie >= fde[1] - sizeof(*fde)
526 || (*cie & (sizeof(*cie) - 1))
527 || (cie[1] != CIE_ID))
528 return NULL; /* this is not a (valid) CIE */
529 return cie;
530}
531
532static unsigned long read_pointer(const u8 **pLoc, const void *end,
533 signed ptrType)
534{
535 unsigned long value = 0;
536 union {
537 const u8 *p8;
538 const u16 *p16u;
539 const s16 *p16s;
540 const u32 *p32u;
541 const s32 *p32s;
542 const unsigned long *pul;
543 } ptr;
544
545 if (ptrType < 0 || ptrType == DW_EH_PE_omit)
546 return 0;
547 ptr.p8 = *pLoc;
548 switch (ptrType & DW_EH_PE_FORM) {
549 case DW_EH_PE_data2:
550 if (end < (const void *)(ptr.p16u + 1))
551 return 0;
552 if (ptrType & DW_EH_PE_signed)
553 value = get_unaligned((u16 *) ptr.p16s++);
554 else
555 value = get_unaligned((u16 *) ptr.p16u++);
556 break;
557 case DW_EH_PE_data4:
558#ifdef CONFIG_64BIT
559 if (end < (const void *)(ptr.p32u + 1))
560 return 0;
561 if (ptrType & DW_EH_PE_signed)
562 value = get_unaligned(ptr.p32s++);
563 else
564 value = get_unaligned(ptr.p32u++);
565 break;
566 case DW_EH_PE_data8:
567 BUILD_BUG_ON(sizeof(u64) != sizeof(value));
568#else
569 BUILD_BUG_ON(sizeof(u32) != sizeof(value));
570#endif
571 fallthrough;
572 case DW_EH_PE_native:
573 if (end < (const void *)(ptr.pul + 1))
574 return 0;
575 value = get_unaligned((unsigned long *)ptr.pul++);
576 break;
577 case DW_EH_PE_leb128:
578 BUILD_BUG_ON(sizeof(uleb128_t) > sizeof(value));
579 value = ptrType & DW_EH_PE_signed ? get_sleb128(&ptr.p8, end)
580 : get_uleb128(&ptr.p8, end);
581 if ((const void *)ptr.p8 > end)
582 return 0;
583 break;
584 default:
585 return 0;
586 }
587 switch (ptrType & DW_EH_PE_ADJUST) {
588 case DW_EH_PE_abs:
589 break;
590 case DW_EH_PE_pcrel:
591 value += (unsigned long)*pLoc;
592 break;
593 default:
594 return 0;
595 }
596 if ((ptrType & DW_EH_PE_indirect)
597 && __get_user(value, (unsigned long __user *)value))
598 return 0;
599 *pLoc = ptr.p8;
600
601 return value;
602}
603
604static signed fde_pointer_type(const u32 *cie)
605{
606 const u8 *ptr = (const u8 *)(cie + 2);
607 unsigned int version = *ptr;
608
609 if (*++ptr) {
610 const char *aug;
611 const u8 *end = (const u8 *)(cie + 1) + *cie;
612 uleb128_t len;
613
614 /* check if augmentation size is first (and thus present) */
615 if (*ptr != 'z')
616 return -1;
617
618 /* check if augmentation string is nul-terminated */
619 aug = (const void *)ptr;
620 ptr = memchr(aug, 0, end - ptr);
621 if (ptr == NULL)
622 return -1;
623
624 ++ptr; /* skip terminator */
625 get_uleb128(&ptr, end); /* skip code alignment */
626 get_sleb128(&ptr, end); /* skip data alignment */
627 /* skip return address column */
628 version <= 1 ? (void) ++ptr : (void)get_uleb128(&ptr, end);
629 len = get_uleb128(&ptr, end); /* augmentation length */
630
631 if (ptr + len < ptr || ptr + len > end)
632 return -1;
633
634 end = ptr + len;
635 while (*++aug) {
636 if (ptr >= end)
637 return -1;
638 switch (*aug) {
639 case 'L':
640 ++ptr;
641 break;
642 case 'P':{
643 signed ptrType = *ptr++;
644
645 if (!read_pointer(&ptr, end, ptrType)
646 || ptr > end)
647 return -1;
648 }
649 break;
650 case 'R':
651 return *ptr;
652 default:
653 return -1;
654 }
655 }
656 }
657 return DW_EH_PE_native | DW_EH_PE_abs;
658}
659
660static int advance_loc(unsigned long delta, struct unwind_state *state)
661{
662 state->loc += delta * state->codeAlign;
663
664 /* FIXME_Rajesh: Probably we are defining for the initial range as well;
665 return delta > 0;
666 */
667 unw_debug("delta %3lu => loc 0x%lx: ", delta, state->loc);
668 return 1;
669}
670
671static void set_rule(uleb128_t reg, enum item_location where, uleb128_t value,
672 struct unwind_state *state)
673{
674 if (reg < ARRAY_SIZE(state->regs)) {
675 state->regs[reg].where = where;
676 state->regs[reg].value = value;
677
678#ifdef UNWIND_DEBUG
679 unw_debug("r%lu: ", reg);
680 switch (where) {
681 case Nowhere:
682 unw_debug("s ");
683 break;
684 case Memory:
685 unw_debug("c(%lu) ", value);
686 break;
687 case Register:
688 unw_debug("r(%lu) ", value);
689 break;
690 case Value:
691 unw_debug("v(%lu) ", value);
692 break;
693 default:
694 break;
695 }
696#endif
697 }
698}
699
700static int processCFI(const u8 *start, const u8 *end, unsigned long targetLoc,
701 signed ptrType, struct unwind_state *state)
702{
703 union {
704 const u8 *p8;
705 const u16 *p16;
706 const u32 *p32;
707 } ptr;
708 int result = 1;
709 u8 opcode;
710
711 if (start != state->cieStart) {
712 state->loc = state->org;
713 result =
714 processCFI(state->cieStart, state->cieEnd, 0, ptrType,
715 state);
716 if (targetLoc == 0 && state->label == NULL)
717 return result;
718 }
719 for (ptr.p8 = start; result && ptr.p8 < end;) {
720 switch (*ptr.p8 >> 6) {
721 uleb128_t value;
722
723 case 0:
724 opcode = *ptr.p8++;
725
726 switch (opcode) {
727 case DW_CFA_nop:
728 unw_debug("cfa nop ");
729 break;
730 case DW_CFA_set_loc:
731 state->loc = read_pointer(&ptr.p8, end,
732 ptrType);
733 if (state->loc == 0)
734 result = 0;
735 unw_debug("cfa_set_loc: 0x%lx ", state->loc);
736 break;
737 case DW_CFA_advance_loc1:
738 unw_debug("\ncfa advance loc1:");
739 result = ptr.p8 < end
740 && advance_loc(*ptr.p8++, state);
741 break;
742 case DW_CFA_advance_loc2:
743 value = *ptr.p8++;
744 value += *ptr.p8++ << 8;
745 unw_debug("\ncfa advance loc2:");
746 result = ptr.p8 <= end + 2
747 /* && advance_loc(*ptr.p16++, state); */
748 && advance_loc(value, state);
749 break;
750 case DW_CFA_advance_loc4:
751 unw_debug("\ncfa advance loc4:");
752 result = ptr.p8 <= end + 4
753 && advance_loc(*ptr.p32++, state);
754 break;
755 case DW_CFA_offset_extended:
756 value = get_uleb128(&ptr.p8, end);
757 unw_debug("cfa_offset_extended: ");
758 set_rule(value, Memory,
759 get_uleb128(&ptr.p8, end), state);
760 break;
761 case DW_CFA_val_offset:
762 value = get_uleb128(&ptr.p8, end);
763 set_rule(value, Value,
764 get_uleb128(&ptr.p8, end), state);
765 break;
766 case DW_CFA_offset_extended_sf:
767 value = get_uleb128(&ptr.p8, end);
768 set_rule(value, Memory,
769 get_sleb128(&ptr.p8, end), state);
770 break;
771 case DW_CFA_val_offset_sf:
772 value = get_uleb128(&ptr.p8, end);
773 set_rule(value, Value,
774 get_sleb128(&ptr.p8, end), state);
775 break;
776 case DW_CFA_restore_extended:
777 unw_debug("cfa_restore_extended: ");
778 case DW_CFA_undefined:
779 unw_debug("cfa_undefined: ");
780 case DW_CFA_same_value:
781 unw_debug("cfa_same_value: ");
782 set_rule(get_uleb128(&ptr.p8, end), Nowhere, 0,
783 state);
784 break;
785 case DW_CFA_register:
786 unw_debug("cfa_register: ");
787 value = get_uleb128(&ptr.p8, end);
788 set_rule(value,
789 Register,
790 get_uleb128(&ptr.p8, end), state);
791 break;
792 case DW_CFA_remember_state:
793 unw_debug("cfa_remember_state: ");
794 if (ptr.p8 == state->label) {
795 state->label = NULL;
796 return 1;
797 }
798 if (state->stackDepth >= MAX_STACK_DEPTH)
799 return 0;
800 state->stack[state->stackDepth++] = ptr.p8;
801 break;
802 case DW_CFA_restore_state:
803 unw_debug("cfa_restore_state: ");
804 if (state->stackDepth) {
805 const uleb128_t loc = state->loc;
806 const u8 *label = state->label;
807
808 state->label =
809 state->stack[state->stackDepth - 1];
810 memcpy(&state->cfa, &badCFA,
811 sizeof(state->cfa));
812 memset(state->regs, 0,
813 sizeof(state->regs));
814 state->stackDepth = 0;
815 result =
816 processCFI(start, end, 0, ptrType,
817 state);
818 state->loc = loc;
819 state->label = label;
820 } else
821 return 0;
822 break;
823 case DW_CFA_def_cfa:
824 state->cfa.reg = get_uleb128(&ptr.p8, end);
825 unw_debug("cfa_def_cfa: r%lu ", state->cfa.reg);
826 fallthrough;
827 case DW_CFA_def_cfa_offset:
828 state->cfa.offs = get_uleb128(&ptr.p8, end);
829 unw_debug("cfa_def_cfa_offset: 0x%lx ",
830 state->cfa.offs);
831 break;
832 case DW_CFA_def_cfa_sf:
833 state->cfa.reg = get_uleb128(&ptr.p8, end);
834 fallthrough;
835 case DW_CFA_def_cfa_offset_sf:
836 state->cfa.offs = get_sleb128(&ptr.p8, end)
837 * state->dataAlign;
838 break;
839 case DW_CFA_def_cfa_register:
840 unw_debug("cfa_def_cfa_register: ");
841 state->cfa.reg = get_uleb128(&ptr.p8, end);
842 break;
843 /*todo case DW_CFA_def_cfa_expression: */
844 /*todo case DW_CFA_expression: */
845 /*todo case DW_CFA_val_expression: */
846 case DW_CFA_GNU_args_size:
847 get_uleb128(&ptr.p8, end);
848 break;
849 case DW_CFA_GNU_negative_offset_extended:
850 value = get_uleb128(&ptr.p8, end);
851 set_rule(value,
852 Memory,
853 (uleb128_t) 0 - get_uleb128(&ptr.p8,
854 end),
855 state);
856 break;
857 case DW_CFA_GNU_window_save:
858 default:
859 unw_debug("UNKNOWN OPCODE 0x%x\n", opcode);
860 result = 0;
861 break;
862 }
863 break;
864 case 1:
865 unw_debug("\ncfa_adv_loc: ");
866 result = advance_loc(*ptr.p8++ & 0x3f, state);
867 break;
868 case 2:
869 unw_debug("cfa_offset: ");
870 value = *ptr.p8++ & 0x3f;
871 set_rule(value, Memory, get_uleb128(&ptr.p8, end),
872 state);
873 break;
874 case 3:
875 unw_debug("cfa_restore: ");
876 set_rule(*ptr.p8++ & 0x3f, Nowhere, 0, state);
877 break;
878 }
879
880 if (ptr.p8 > end)
881 result = 0;
882 if (result && targetLoc != 0 && targetLoc < state->loc)
883 return 1;
884 }
885
886 return result && ptr.p8 == end && (targetLoc == 0 || (
887 /*todo While in theory this should apply, gcc in practice omits
888 everything past the function prolog, and hence the location
889 never reaches the end of the function.
890 targetLoc < state->loc && */ state->label == NULL));
891}
892
893/* Unwind to previous to frame. Returns 0 if successful, negative
894 * number in case of an error. */
895int arc_unwind(struct unwind_frame_info *frame)
896{
897#define FRAME_REG(r, t) (((t *)frame)[reg_info[r].offs])
898 const u32 *fde = NULL, *cie = NULL;
899 const u8 *ptr = NULL, *end = NULL;
900 unsigned long pc = UNW_PC(frame) - frame->call_frame;
901 unsigned long startLoc = 0, endLoc = 0, cfa;
902 unsigned int i;
903 signed ptrType = -1;
904 uleb128_t retAddrReg = 0;
905 const struct unwind_table *table;
906 struct unwind_state state;
907 unsigned long *fptr;
908 unsigned long addr;
909
910 unw_debug("\n\nUNWIND FRAME:\n");
911 unw_debug("PC: 0x%lx BLINK: 0x%lx, SP: 0x%lx, FP: 0x%x\n",
912 UNW_PC(frame), UNW_BLINK(frame), UNW_SP(frame),
913 UNW_FP(frame));
914
915 if (UNW_PC(frame) == 0)
916 return -EINVAL;
917
918#ifdef UNWIND_DEBUG
919 {
920 unsigned long *sptr = (unsigned long *)UNW_SP(frame);
921 unw_debug("\nStack Dump:\n");
922 for (i = 0; i < 20; i++, sptr++)
923 unw_debug("0x%p: 0x%lx\n", sptr, *sptr);
924 unw_debug("\n");
925 }
926#endif
927
928 table = find_table(pc);
929 if (table != NULL
930 && !(table->size & (sizeof(*fde) - 1))) {
931 const u8 *hdr = table->header;
932 unsigned long tableSize;
933
934 smp_rmb();
935 if (hdr && hdr[0] == 1) {
936 switch (hdr[3] & DW_EH_PE_FORM) {
937 case DW_EH_PE_native:
938 tableSize = sizeof(unsigned long);
939 break;
940 case DW_EH_PE_data2:
941 tableSize = 2;
942 break;
943 case DW_EH_PE_data4:
944 tableSize = 4;
945 break;
946 case DW_EH_PE_data8:
947 tableSize = 8;
948 break;
949 default:
950 tableSize = 0;
951 break;
952 }
953 ptr = hdr + 4;
954 end = hdr + table->hdrsz;
955 if (tableSize && read_pointer(&ptr, end, hdr[1])
956 == (unsigned long)table->address
957 && (i = read_pointer(&ptr, end, hdr[2])) > 0
958 && i == (end - ptr) / (2 * tableSize)
959 && !((end - ptr) % (2 * tableSize))) {
960 do {
961 const u8 *cur =
962 ptr + (i / 2) * (2 * tableSize);
963
964 startLoc = read_pointer(&cur,
965 cur + tableSize,
966 hdr[3]);
967 if (pc < startLoc)
968 i /= 2;
969 else {
970 ptr = cur - tableSize;
971 i = (i + 1) / 2;
972 }
973 } while (startLoc && i > 1);
974 if (i == 1
975 && (startLoc = read_pointer(&ptr,
976 ptr + tableSize,
977 hdr[3])) != 0
978 && pc >= startLoc)
979 fde = (void *)read_pointer(&ptr,
980 ptr +
981 tableSize,
982 hdr[3]);
983 }
984 }
985
986 if (fde != NULL) {
987 cie = cie_for_fde(fde, table);
988 ptr = (const u8 *)(fde + 2);
989 if (cie != NULL
990 && cie != &bad_cie
991 && cie != ¬_fde
992 && (ptrType = fde_pointer_type(cie)) >= 0
993 && read_pointer(&ptr,
994 (const u8 *)(fde + 1) + *fde,
995 ptrType) == startLoc) {
996 if (!(ptrType & DW_EH_PE_indirect))
997 ptrType &=
998 DW_EH_PE_FORM | DW_EH_PE_signed;
999 endLoc =
1000 startLoc + read_pointer(&ptr,
1001 (const u8 *)(fde +
1002 1) +
1003 *fde, ptrType);
1004 if (pc >= endLoc) {
1005 fde = NULL;
1006 cie = NULL;
1007 }
1008 } else {
1009 fde = NULL;
1010 cie = NULL;
1011 }
1012 }
1013 }
1014 if (cie != NULL) {
1015 memset(&state, 0, sizeof(state));
1016 state.cieEnd = ptr; /* keep here temporarily */
1017 ptr = (const u8 *)(cie + 2);
1018 end = (const u8 *)(cie + 1) + *cie;
1019 frame->call_frame = 1;
1020 if (*++ptr) {
1021 /* check if augmentation size is first (thus present) */
1022 if (*ptr == 'z') {
1023 while (++ptr < end && *ptr) {
1024 switch (*ptr) {
1025 /* chk for ignorable or already handled
1026 * nul-terminated augmentation string */
1027 case 'L':
1028 case 'P':
1029 case 'R':
1030 continue;
1031 case 'S':
1032 frame->call_frame = 0;
1033 continue;
1034 default:
1035 break;
1036 }
1037 break;
1038 }
1039 }
1040 if (ptr >= end || *ptr)
1041 cie = NULL;
1042 }
1043 ++ptr;
1044 }
1045 if (cie != NULL) {
1046 /* get code alignment factor */
1047 state.codeAlign = get_uleb128(&ptr, end);
1048 /* get data alignment factor */
1049 state.dataAlign = get_sleb128(&ptr, end);
1050 if (state.codeAlign == 0 || state.dataAlign == 0 || ptr >= end)
1051 cie = NULL;
1052 else {
1053 retAddrReg =
1054 state.version <= 1 ? *ptr++ : get_uleb128(&ptr,
1055 end);
1056 unw_debug("CIE Frame Info:\n");
1057 unw_debug("return Address register 0x%lx\n",
1058 retAddrReg);
1059 unw_debug("data Align: %ld\n", state.dataAlign);
1060 unw_debug("code Align: %lu\n", state.codeAlign);
1061 /* skip augmentation */
1062 if (((const char *)(cie + 2))[1] == 'z') {
1063 uleb128_t augSize = get_uleb128(&ptr, end);
1064
1065 ptr += augSize;
1066 }
1067 if (ptr > end || retAddrReg >= ARRAY_SIZE(reg_info)
1068 || REG_INVALID(retAddrReg)
1069 || reg_info[retAddrReg].width !=
1070 sizeof(unsigned long))
1071 cie = NULL;
1072 }
1073 }
1074 if (cie != NULL) {
1075 state.cieStart = ptr;
1076 ptr = state.cieEnd;
1077 state.cieEnd = end;
1078 end = (const u8 *)(fde + 1) + *fde;
1079 /* skip augmentation */
1080 if (((const char *)(cie + 2))[1] == 'z') {
1081 uleb128_t augSize = get_uleb128(&ptr, end);
1082
1083 if ((ptr += augSize) > end)
1084 fde = NULL;
1085 }
1086 }
1087 if (cie == NULL || fde == NULL) {
1088#ifdef CONFIG_FRAME_POINTER
1089 unsigned long top, bottom;
1090
1091 top = STACK_TOP_UNW(frame->task);
1092 bottom = STACK_BOTTOM_UNW(frame->task);
1093#if FRAME_RETADDR_OFFSET < 0
1094 if (UNW_SP(frame) < top && UNW_FP(frame) <= UNW_SP(frame)
1095 && bottom < UNW_FP(frame)
1096#else
1097 if (UNW_SP(frame) > top && UNW_FP(frame) >= UNW_SP(frame)
1098 && bottom > UNW_FP(frame)
1099#endif
1100 && !((UNW_SP(frame) | UNW_FP(frame))
1101 & (sizeof(unsigned long) - 1))) {
1102 unsigned long link;
1103
1104 if (!__get_user(link, (unsigned long *)
1105 (UNW_FP(frame) + FRAME_LINK_OFFSET))
1106#if FRAME_RETADDR_OFFSET < 0
1107 && link > bottom && link < UNW_FP(frame)
1108#else
1109 && link > UNW_FP(frame) && link < bottom
1110#endif
1111 && !(link & (sizeof(link) - 1))
1112 && !__get_user(UNW_PC(frame),
1113 (unsigned long *)(UNW_FP(frame)
1114 + FRAME_RETADDR_OFFSET)))
1115 {
1116 UNW_SP(frame) =
1117 UNW_FP(frame) + FRAME_RETADDR_OFFSET
1118#if FRAME_RETADDR_OFFSET < 0
1119 -
1120#else
1121 +
1122#endif
1123 sizeof(UNW_PC(frame));
1124 UNW_FP(frame) = link;
1125 return 0;
1126 }
1127 }
1128#endif
1129 return -ENXIO;
1130 }
1131 state.org = startLoc;
1132 memcpy(&state.cfa, &badCFA, sizeof(state.cfa));
1133
1134 unw_debug("\nProcess instructions\n");
1135
1136 /* process instructions
1137 * For ARC, we optimize by having blink(retAddrReg) with
1138 * the sameValue in the leaf function, so we should not check
1139 * state.regs[retAddrReg].where == Nowhere
1140 */
1141 if (!processCFI(ptr, end, pc, ptrType, &state)
1142 || state.loc > endLoc
1143/* || state.regs[retAddrReg].where == Nowhere */
1144 || state.cfa.reg >= ARRAY_SIZE(reg_info)
1145 || reg_info[state.cfa.reg].width != sizeof(unsigned long)
1146 || state.cfa.offs % sizeof(unsigned long))
1147 return -EIO;
1148
1149#ifdef UNWIND_DEBUG
1150 unw_debug("\n");
1151
1152 unw_debug("\nRegister State Based on the rules parsed from FDE:\n");
1153 for (i = 0; i < ARRAY_SIZE(state.regs); ++i) {
1154
1155 if (REG_INVALID(i))
1156 continue;
1157
1158 switch (state.regs[i].where) {
1159 case Nowhere:
1160 break;
1161 case Memory:
1162 unw_debug(" r%d: c(%lu),", i, state.regs[i].value);
1163 break;
1164 case Register:
1165 unw_debug(" r%d: r(%lu),", i, state.regs[i].value);
1166 break;
1167 case Value:
1168 unw_debug(" r%d: v(%lu),", i, state.regs[i].value);
1169 break;
1170 }
1171 }
1172
1173 unw_debug("\n");
1174#endif
1175
1176 /* update frame */
1177 if (frame->call_frame
1178 && !UNW_DEFAULT_RA(state.regs[retAddrReg], state.dataAlign))
1179 frame->call_frame = 0;
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);
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);