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unwind_x86_32_64.c
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unwind_x86_32_64.c
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/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#if defined(X86_64)
/*
* Support for genarating DWARF CFI based backtraces.
* Borrowed heavily from the kernel's implementation of unwinding using the
* DWARF CFI written by Jan Beulich
*/
#ifdef X86_64
#include "unwind_x86_64.h"
#endif
#ifdef X86
#include "unwind_x86.h"
#endif
#include "defs.h"
#define MAX_STACK_DEPTH 8
static struct local_unwind_table {
struct {
unsigned long pc;
unsigned long range;
} core, init;
void *address;
unsigned long size;
} *local_unwind_tables, default_unwind_table;
static int gather_in_memory_unwind_tables(void);
static int populate_local_tables(ulong, char *);
static int unwind_tables_cnt = 0;
static struct local_unwind_table *find_table(unsigned long);
static void dump_local_unwind_tables(void);
static const struct {
unsigned offs:BITS_PER_LONG / 2;
unsigned width:BITS_PER_LONG / 2;
} reg_info[] = {
UNW_REGISTER_INFO
};
#undef PTREGS_INFO
#undef EXTRA_INFO
#ifndef REG_INVALID
#define REG_INVALID(r) (reg_info[r].width == 0)
#endif
#define DW_CFA_nop 0x00
#define DW_CFA_set_loc 0x01
#define DW_CFA_advance_loc1 0x02
#define DW_CFA_advance_loc2 0x03
#define DW_CFA_advance_loc4 0x04
#define DW_CFA_offset_extended 0x05
#define DW_CFA_restore_extended 0x06
#define DW_CFA_undefined 0x07
#define DW_CFA_same_value 0x08
#define DW_CFA_register 0x09
#define DW_CFA_remember_state 0x0a
#define DW_CFA_restore_state 0x0b
#define DW_CFA_def_cfa 0x0c
#define DW_CFA_def_cfa_register 0x0d
#define DW_CFA_def_cfa_offset 0x0e
#define DW_CFA_def_cfa_expression 0x0f
#define DW_CFA_expression 0x10
#define DW_CFA_offset_extended_sf 0x11
#define DW_CFA_def_cfa_sf 0x12
#define DW_CFA_def_cfa_offset_sf 0x13
#define DW_CFA_val_offset 0x14
#define DW_CFA_val_offset_sf 0x15
#define DW_CFA_val_expression 0x16
#define DW_CFA_lo_user 0x1c
#define DW_CFA_GNU_window_save 0x2d
#define DW_CFA_GNU_args_size 0x2e
#define DW_CFA_GNU_negative_offset_extended 0x2f
#define DW_CFA_hi_user 0x3f
#define DW_EH_PE_FORM 0x07
#define DW_EH_PE_native 0x00
#define DW_EH_PE_leb128 0x01
#define DW_EH_PE_data2 0x02
#define DW_EH_PE_data4 0x03
#define DW_EH_PE_data8 0x04
#define DW_EH_PE_signed 0x08
#define DW_EH_PE_ADJUST 0x70
#define DW_EH_PE_abs 0x00
#define DW_EH_PE_pcrel 0x10
#define DW_EH_PE_textrel 0x20
#define DW_EH_PE_datarel 0x30
#define DW_EH_PE_funcrel 0x40
#define DW_EH_PE_aligned 0x50
#define DW_EH_PE_indirect 0x80
#define DW_EH_PE_omit 0xff
#define min(x,y) ({ \
typeof(x) _x = (x); \
typeof(y) _y = (y); \
(void) (&_x == &_y); \
_x < _y ? _x : _y; })
#define max(x,y) ({ \
typeof(x) _x = (x); \
typeof(y) _y = (y); \
(void) (&_x == &_y); \
_x > _y ? _x : _y; })
#define STACK_LIMIT(ptr) (((ptr) - 1) & ~(THREAD_SIZE - 1))
typedef unsigned long uleb128_t;
typedef signed long sleb128_t;
struct unwind_item {
enum item_location {
Nowhere,
Memory,
Register,
Value
} where;
uleb128_t value;
};
struct unwind_state {
uleb128_t loc, org;
const u8 *cieStart, *cieEnd;
uleb128_t codeAlign;
sleb128_t dataAlign;
struct cfa {
uleb128_t reg, offs;
} cfa;
struct unwind_item regs[ARRAY_SIZE(reg_info)];
unsigned stackDepth:8;
unsigned version:8;
const u8 *label;
const u8 *stack[MAX_STACK_DEPTH];
};
static const struct cfa badCFA = { ARRAY_SIZE(reg_info), 1 };
static uleb128_t get_uleb128(const u8 **pcur, const u8 *end)
{
const u8 *cur = *pcur;
uleb128_t value;
unsigned shift;
for (shift = 0, value = 0; cur < end; shift += 7) {
if (shift + 7 > 8 * sizeof(value)
&& (*cur & 0x7fU) >= (1U << (8 * sizeof(value) - shift))) {
cur = end + 1;
break;
}
value |= (uleb128_t)(*cur & 0x7f) << shift;
if (!(*cur++ & 0x80))
break;
}
*pcur = cur;
return value;
}
static sleb128_t get_sleb128(const u8 **pcur, const u8 *end)
{
const u8 *cur = *pcur;
sleb128_t value;
unsigned shift;
for (shift = 0, value = 0; cur < end; shift += 7) {
if (shift + 7 > 8 * sizeof(value)
&& (*cur & 0x7fU) >= (1U << (8 * sizeof(value) - shift))) {
cur = end + 1;
break;
}
value |= (sleb128_t)(*cur & 0x7f) << shift;
if (!(*cur & 0x80)) {
value |= -(*cur++ & 0x40) << shift;
break;
}
}
*pcur = cur;
return value;
}
static unsigned long read_pointer(const u8 **pLoc,
const void *end,
signed ptrType)
{
unsigned long value = 0;
union {
const u8 *p8;
const u16 *p16u;
const s16 *p16s;
const u32 *p32u;
const s32 *p32s;
const unsigned long *pul;
} ptr;
if (ptrType < 0 || ptrType == DW_EH_PE_omit)
return 0;
ptr.p8 = *pLoc;
switch(ptrType & DW_EH_PE_FORM) {
case DW_EH_PE_data2:
if (end < (const void *)(ptr.p16u + 1))
return 0;
if(ptrType & DW_EH_PE_signed)
value = get_unaligned(ptr.p16s++);
else
value = get_unaligned(ptr.p16u++);
break;
case DW_EH_PE_data4:
#ifdef CONFIG_64BIT
if (end < (const void *)(ptr.p32u + 1))
return 0;
if(ptrType & DW_EH_PE_signed)
value = get_unaligned(ptr.p32s++);
else
value = get_unaligned(ptr.p32u++);
break;
case DW_EH_PE_data8:
BUILD_BUG_ON(sizeof(u64) != sizeof(value));
#else
BUILD_BUG_ON(sizeof(u32) != sizeof(value));
#endif
case DW_EH_PE_native:
if (end < (const void *)(ptr.pul + 1))
return 0;
value = get_unaligned(ptr.pul++);
break;
case DW_EH_PE_leb128:
BUILD_BUG_ON(sizeof(uleb128_t) > sizeof(value));
value = ptrType & DW_EH_PE_signed
? get_sleb128(&ptr.p8, end)
: get_uleb128(&ptr.p8, end);
if ((const void *)ptr.p8 > end)
return 0;
break;
default:
return 0;
}
switch(ptrType & DW_EH_PE_ADJUST) {
case DW_EH_PE_abs:
break;
case DW_EH_PE_pcrel:
value += (unsigned long)*pLoc;
break;
default:
return 0;
}
/* TBD
if ((ptrType & DW_EH_PE_indirect)
&& __get_user(value, (unsigned long *)value))
return 0;
*/
*pLoc = ptr.p8;
return value;
}
static signed fde_pointer_type(const u32 *cie)
{
const u8 *ptr = (const u8 *)(cie + 2);
unsigned version = *ptr;
if (version != 1)
return -1; /* unsupported */
if (*++ptr) {
const char *aug;
const u8 *end = (const u8 *)(cie + 1) + *cie;
uleb128_t len;
/* check if augmentation size is first (and thus present) */
if (*ptr != 'z')
return -1;
/* check if augmentation string is nul-terminated */
if ((ptr = memchr(aug = (const void *)ptr, 0, end - ptr)) == NULL)
return -1;
++ptr; /* skip terminator */
get_uleb128(&ptr, end); /* skip code alignment */
get_sleb128(&ptr, end); /* skip data alignment */
/* skip return address column */
version <= 1 ? (void)++ptr : (void)get_uleb128(&ptr, end);
len = get_uleb128(&ptr, end); /* augmentation length */
if (ptr + len < ptr || ptr + len > end)
return -1;
end = ptr + len;
while (*++aug) {
if (ptr >= end)
return -1;
switch(*aug) {
case 'L':
++ptr;
break;
case 'P': {
signed ptrType = *ptr++;
if (!read_pointer(&ptr, end, ptrType) || ptr > end)
return -1;
}
break;
case 'R':
return *ptr;
default:
return -1;
}
}
}
return DW_EH_PE_native|DW_EH_PE_abs;
}
static int advance_loc(unsigned long delta, struct unwind_state *state)
{
state->loc += delta * state->codeAlign;
return delta > 0;
}
static void set_rule(uleb128_t reg,
enum item_location where,
uleb128_t value,
struct unwind_state *state)
{
if (reg < ARRAY_SIZE(state->regs)) {
state->regs[reg].where = where;
state->regs[reg].value = value;
}
}
static int processCFI(const u8 *start,
const u8 *end,
unsigned long targetLoc,
signed ptrType,
struct unwind_state *state)
{
union {
const u8 *p8;
const u16 *p16;
const u32 *p32;
} ptr;
int result = 1;
if (start != state->cieStart) {
state->loc = state->org;
result = processCFI(state->cieStart, state->cieEnd, 0, ptrType, state);
if (targetLoc == 0 && state->label == NULL)
return result;
}
for (ptr.p8 = start; result && ptr.p8 < end; ) {
switch(*ptr.p8 >> 6) {
uleb128_t value;
case 0:
switch(*ptr.p8++) {
case DW_CFA_nop:
break;
case DW_CFA_set_loc:
if ((state->loc = read_pointer(&ptr.p8, end,
ptrType)) == 0)
result = 0;
break;
case DW_CFA_advance_loc1:
result = ptr.p8 < end && advance_loc(*ptr.p8++, state);
break;
case DW_CFA_advance_loc2:
result = ptr.p8 <= end + 2
&& advance_loc(*ptr.p16++, state);
break;
case DW_CFA_advance_loc4:
result = ptr.p8 <= end + 4
&& advance_loc(*ptr.p32++, state);
break;
case DW_CFA_offset_extended:
value = get_uleb128(&ptr.p8, end);
set_rule(value, Memory,
get_uleb128(&ptr.p8, end), state);
break;
case DW_CFA_val_offset:
value = get_uleb128(&ptr.p8, end);
set_rule(value, Value,
get_uleb128(&ptr.p8, end), state);
break;
case DW_CFA_offset_extended_sf:
value = get_uleb128(&ptr.p8, end);
set_rule(value, Memory,
get_sleb128(&ptr.p8, end), state);
break;
case DW_CFA_val_offset_sf:
value = get_uleb128(&ptr.p8, end);
set_rule(value, Value,
get_sleb128(&ptr.p8, end), state);
break;
case DW_CFA_restore_extended:
case DW_CFA_undefined:
case DW_CFA_same_value:
set_rule(get_uleb128(&ptr.p8, end), Nowhere, 0, state);
break;
case DW_CFA_register:
value = get_uleb128(&ptr.p8, end);
set_rule(value, Register,
get_uleb128(&ptr.p8, end), state);
break;
case DW_CFA_remember_state:
if (ptr.p8 == state->label) {
state->label = NULL;
return 1;
}
if (state->stackDepth >= MAX_STACK_DEPTH)
return 0;
state->stack[state->stackDepth++] = ptr.p8;
break;
case DW_CFA_restore_state:
if (state->stackDepth) {
const uleb128_t loc = state->loc;
const u8 *label = state->label;
state->label = state->stack[state->stackDepth - 1];
memcpy(&state->cfa, &badCFA, sizeof(state->cfa));
memset(state->regs, 0, sizeof(state->regs));
state->stackDepth = 0;
result = processCFI(start, end, 0, ptrType, state);
state->loc = loc;
state->label = label;
} else
return 0;
break;
case DW_CFA_def_cfa:
state->cfa.reg = get_uleb128(&ptr.p8, end);
/*nobreak*/
case DW_CFA_def_cfa_offset:
state->cfa.offs = get_uleb128(&ptr.p8, end);
break;
case DW_CFA_def_cfa_sf:
state->cfa.reg = get_uleb128(&ptr.p8, end);
/*nobreak*/
case DW_CFA_def_cfa_offset_sf:
state->cfa.offs = get_sleb128(&ptr.p8, end)
* state->dataAlign;
break;
case DW_CFA_def_cfa_register:
state->cfa.reg = get_uleb128(&ptr.p8, end);
break;
/*todo case DW_CFA_def_cfa_expression: */
/*todo case DW_CFA_expression: */
/*todo case DW_CFA_val_expression: */
case DW_CFA_GNU_args_size:
get_uleb128(&ptr.p8, end);
break;
case DW_CFA_GNU_negative_offset_extended:
value = get_uleb128(&ptr.p8, end);
set_rule(value, Memory, (uleb128_t)0 -
get_uleb128(&ptr.p8, end), state);
break;
case DW_CFA_GNU_window_save:
default:
result = 0;
break;
}
break;
case 1:
result = advance_loc(*ptr.p8++ & 0x3f, state);
break;
case 2:
value = *ptr.p8++ & 0x3f;
set_rule(value, Memory, get_uleb128(&ptr.p8, end),
state);
break;
case 3:
set_rule(*ptr.p8++ & 0x3f, Nowhere, 0, state);
break;
}
if (ptr.p8 > end)
result = 0;
if (result && targetLoc != 0 && targetLoc < state->loc)
return 1;
}
return result
&& ptr.p8 == end
&& (targetLoc == 0
|| (/*todo While in theory this should apply, gcc in practice omits
everything past the function prolog, and hence the location
never reaches the end of the function.
targetLoc < state->loc &&*/ state->label == NULL));
}
/* Unwind to previous to frame. Returns 0 if successful, negative
* number in case of an error. */
int
unwind(struct unwind_frame_info *frame, int is_ehframe)
{
#define FRAME_REG(r, t) (((t *)frame)[reg_info[r].offs])
const u32 *fde = NULL, *cie = NULL;
const u8 *ptr = NULL, *end = NULL;
unsigned long startLoc = 0, endLoc = 0, cfa;
unsigned i;
signed ptrType = -1;
uleb128_t retAddrReg = 0;
// struct unwind_table *table;
void *unwind_table;
struct local_unwind_table *table;
struct unwind_state state;
u64 reg_ptr = 0;
if (UNW_PC(frame) == 0)
return -EINVAL;
if ((table = find_table(UNW_PC(frame)))) {
// unsigned long tableSize = unwind_table_size;
unsigned long tableSize = table->size;
unwind_table = table->address;
for (fde = unwind_table;
tableSize > sizeof(*fde) && tableSize - sizeof(*fde) >= *fde;
tableSize -= sizeof(*fde) + *fde,
fde += 1 + *fde / sizeof(*fde)) {
if (!*fde || (*fde & (sizeof(*fde) - 1)))
break;
if (is_ehframe && !fde[1])
continue; /* this is a CIE */
else if (fde[1] == 0xffffffff)
continue; /* this is a CIE */
if ((fde[1] & (sizeof(*fde) - 1))
|| fde[1] > (unsigned long)(fde + 1)
- (unsigned long)unwind_table)
continue; /* this is not a valid FDE */
if (is_ehframe)
cie = fde + 1 - fde[1] / sizeof(*fde);
else
cie = unwind_table + fde[1];
if (*cie <= sizeof(*cie) + 4
|| *cie >= fde[1] - sizeof(*fde)
|| (*cie & (sizeof(*cie) - 1))
|| (cie[1] != 0xffffffff && cie[1])
|| (ptrType = fde_pointer_type(cie)) < 0) {
cie = NULL; /* this is not a (valid) CIE */
continue;
}
ptr = (const u8 *)(fde + 2);
startLoc = read_pointer(&ptr,
(const u8 *)(fde + 1) + *fde,
ptrType);
endLoc = startLoc
+ read_pointer(&ptr,
(const u8 *)(fde + 1) + *fde,
ptrType & DW_EH_PE_indirect
? ptrType
: ptrType & (DW_EH_PE_FORM|DW_EH_PE_signed));
if (UNW_PC(frame) >= startLoc && UNW_PC(frame) < endLoc)
break;
cie = NULL;
}
}
if (cie != NULL) {
memset(&state, 0, sizeof(state));
state.cieEnd = ptr; /* keep here temporarily */
ptr = (const u8 *)(cie + 2);
end = (const u8 *)(cie + 1) + *cie;
if ((state.version = *ptr) != 1)
cie = NULL; /* unsupported version */
else if (*++ptr) {
/* check if augmentation size is first (and thus present) */
if (*ptr == 'z') {
/* check for ignorable (or already handled)
* nul-terminated augmentation string */
while (++ptr < end && *ptr)
if (strchr("LPR", *ptr) == NULL)
break;
}
if (ptr >= end || *ptr)
cie = NULL;
}
++ptr;
}
if (cie != NULL) {
/* get code aligment factor */
state.codeAlign = get_uleb128(&ptr, end);
/* get data aligment factor */
state.dataAlign = get_sleb128(&ptr, end);
if (state.codeAlign == 0 || state.dataAlign == 0 || ptr >= end)
cie = NULL;
else {
retAddrReg = state.version <= 1 ? *ptr++ : get_uleb128(&ptr, end);
/* skip augmentation */
if (((const char *)(cie + 2))[1] == 'z')
ptr += get_uleb128(&ptr, end);
if (ptr > end
|| retAddrReg >= ARRAY_SIZE(reg_info)
|| REG_INVALID(retAddrReg)
|| reg_info[retAddrReg].width != sizeof(unsigned long))
cie = NULL;
}
}
if (cie != NULL) {
state.cieStart = ptr;
ptr = state.cieEnd;
state.cieEnd = end;
end = (const u8 *)(fde + 1) + *fde;
/* skip augmentation */
if (((const char *)(cie + 2))[1] == 'z') {
uleb128_t augSize = get_uleb128(&ptr, end);
if ((ptr += augSize) > end)
fde = NULL;
}
}
if (cie == NULL || fde == NULL)
return -ENXIO;
state.org = startLoc;
memcpy(&state.cfa, &badCFA, sizeof(state.cfa));
/* process instructions */
if (!processCFI(ptr, end, UNW_PC(frame), ptrType, &state)
|| state.loc > endLoc
|| state.regs[retAddrReg].where == Nowhere
|| state.cfa.reg >= ARRAY_SIZE(reg_info)
|| reg_info[state.cfa.reg].width != sizeof(unsigned long)
|| state.cfa.offs % sizeof(unsigned long)) {
return -EIO;
}
/* update frame */
cfa = FRAME_REG(state.cfa.reg, unsigned long) + state.cfa.offs;
startLoc = min((unsigned long)UNW_SP(frame), cfa);
endLoc = max((unsigned long)UNW_SP(frame), cfa);
if (STACK_LIMIT(startLoc) != STACK_LIMIT(endLoc)) {
startLoc = min(STACK_LIMIT(cfa), cfa);
endLoc = max(STACK_LIMIT(cfa), cfa);
}
#ifndef CONFIG_64BIT
# define CASES CASE(8); CASE(16); CASE(32)
#else
# define CASES CASE(8); CASE(16); CASE(32); CASE(64)
#endif
for (i = 0; i < ARRAY_SIZE(state.regs); ++i) {
if (REG_INVALID(i)) {
if (state.regs[i].where == Nowhere)
continue;
return -EIO;
}
switch(state.regs[i].where) {
default:
break;
case Register:
if (state.regs[i].value >= ARRAY_SIZE(reg_info)
|| REG_INVALID(state.regs[i].value)
|| reg_info[i].width > reg_info[state.regs[i].value].width){
return -EIO;
}
switch(reg_info[state.regs[i].value].width) {
#define CASE(n) \
case sizeof(u##n): \
state.regs[i].value = FRAME_REG(state.regs[i].value, \
const u##n); \
break
CASES;
#undef CASE
default:
return -EIO;
}
break;
}
}
for (i = 0; i < ARRAY_SIZE(state.regs); ++i) {
if (REG_INVALID(i))
continue;
switch(state.regs[i].where) {
case Nowhere:
if (reg_info[i].width != sizeof(UNW_SP(frame))
|| &FRAME_REG(i, __typeof__(UNW_SP(frame)))
!= &UNW_SP(frame))
continue;
UNW_SP(frame) = cfa;
break;
case Register:
switch(reg_info[i].width) {
#define CASE(n) case sizeof(u##n): \
FRAME_REG(i, u##n) = state.regs[i].value; \
break
CASES;
#undef CASE
default:
return -EIO;
}
break;
case Value:
if (reg_info[i].width != sizeof(unsigned long)){
return -EIO;}
FRAME_REG(i, unsigned long) = cfa + state.regs[i].value
* state.dataAlign;
break;
case Memory: {
unsigned long addr = cfa + state.regs[i].value
* state.dataAlign;
if ((state.regs[i].value * state.dataAlign)
% sizeof(unsigned long)
|| addr < startLoc
|| addr + sizeof(unsigned long) < addr
|| addr + sizeof(unsigned long) > endLoc){
return -EIO;}
switch(reg_info[i].width) {
#define CASE(n) case sizeof(u##n): \
readmem(addr, KVADDR, ®_ptr,sizeof(u##n), "register", RETURN_ON_ERROR|QUIET); \
FRAME_REG(i, u##n) = (u##n)reg_ptr;\
break
CASES;
#undef CASE
default:
return -EIO;
}
}
break;
}
}
return 0;
#undef CASES
#undef FRAME_REG
}
/*
* Initialize the unwind table(s) in the best-case order:
*
* 1. Use the in-memory kernel and module unwind tables.
* 2. Use the in-memory kernel-only .eh_frame data. (possible?)
* 3. Use the kernel-only .eh_frame data from the vmlinux file.
*/
void
init_unwind_table(void)
{
ulong unwind_table_size;
void *unwind_table;
kt->flags &= ~DWARF_UNWIND;
if (gather_in_memory_unwind_tables()) {
if (CRASHDEBUG(1))
fprintf(fp, "init_unwind_table: DWARF_UNWIND_MEMORY (%d tables)\n",
unwind_tables_cnt);
kt->flags |= DWARF_UNWIND_MEMORY;
if (unwind_tables_cnt > 1)
kt->flags |= DWARF_UNWIND_MODULES;
if (!(kt->flags & NO_DWARF_UNWIND))
kt->flags |= DWARF_UNWIND;
return;
}
if (symbol_exists("__start_unwind") &&
symbol_exists("__end_unwind")) {
unwind_table_size = symbol_value("__end_unwind") -
symbol_value("__start_unwind");
if (!(unwind_table = malloc(unwind_table_size))) {
error(WARNING, "cannot malloc unwind table space\n");
goto try_eh_frame;
}
if (!readmem(symbol_value("__start_unwind"), KVADDR, unwind_table,
unwind_table_size, "unwind table", RETURN_ON_ERROR)) {
error(WARNING, "cannot read unwind table data\n");
free(unwind_table);
goto try_eh_frame;
}
kt->flags |= DWARF_UNWIND_MEMORY;
if (!(kt->flags & NO_DWARF_UNWIND))
kt->flags |= DWARF_UNWIND;
default_unwind_table.size = unwind_table_size;
default_unwind_table.address = unwind_table;
if (CRASHDEBUG(1))
fprintf(fp, "init_unwind_table: DWARF_UNWIND_MEMORY\n");
return;
}
try_eh_frame:
if (st->dwarf_eh_frame_size || st->dwarf_debug_frame_size) {
int fd;
int is_ehframe = (!st->dwarf_debug_frame_size &&
st->dwarf_eh_frame_size);
unwind_table_size = is_ehframe ? st->dwarf_eh_frame_size :
st->dwarf_debug_frame_size;
if (!(unwind_table = malloc(unwind_table_size))) {
error(WARNING, "cannot malloc unwind table space\n");
return;
}
if ((fd = open(pc->namelist, O_RDONLY)) < 0) {
error(WARNING, "cannot open %s for %s data\n",
pc->namelist, is_ehframe ? ".eh_frame" : ".debug_frame");
free(unwind_table);
return;
}
if (is_ehframe)
lseek(fd, st->dwarf_eh_frame_file_offset, SEEK_SET);
else
lseek(fd, st->dwarf_debug_frame_file_offset, SEEK_SET);
if (read(fd, unwind_table, unwind_table_size) !=
unwind_table_size) {
if (CRASHDEBUG(1))
error(WARNING, "cannot read %s data from %s\n",
is_ehframe ? ".eh_frame" : ".debug_frame", pc->namelist);
free(unwind_table);
close(fd);
return;
}
close(fd);
default_unwind_table.size = unwind_table_size;
default_unwind_table.address = unwind_table;
kt->flags |= DWARF_UNWIND_EH_FRAME;
if (!(kt->flags & NO_DWARF_UNWIND))
kt->flags |= DWARF_UNWIND;
if (CRASHDEBUG(1))
fprintf(fp, "init_unwind_table: DWARF_UNWIND_EH_FRAME\n");
return;
}
}
/*
* Find the appropriate kernel-only "root_table" unwind_table,
* and pass it to populate_local_tables() to do the heavy lifting.
*/
static int
gather_in_memory_unwind_tables(void)
{
int i, cnt, found;
struct syment *sp, *root_tables[10];
char *root_table_buf;
char buf[BUFSIZE];
ulong name;
STRUCT_SIZE_INIT(unwind_table, "unwind_table");
MEMBER_OFFSET_INIT(unwind_table_core, "unwind_table", "core");
MEMBER_OFFSET_INIT(unwind_table_init, "unwind_table", "init");
MEMBER_OFFSET_INIT(unwind_table_address, "unwind_table", "address");
MEMBER_OFFSET_INIT(unwind_table_size, "unwind_table", "size");
MEMBER_OFFSET_INIT(unwind_table_link, "unwind_table", "link");
MEMBER_OFFSET_INIT(unwind_table_name, "unwind_table", "name");
if (INVALID_SIZE(unwind_table) ||
INVALID_MEMBER(unwind_table_core) ||
INVALID_MEMBER(unwind_table_init) ||
INVALID_MEMBER(unwind_table_address) ||
INVALID_MEMBER(unwind_table_size) ||
INVALID_MEMBER(unwind_table_link) ||
INVALID_MEMBER(unwind_table_name)) {
if (CRASHDEBUG(1))
error(NOTE,
"unwind_table structure has changed, or does not exist in this kernel\n");
return 0;
}
/*
* Unfortunately there are two kernel root_table symbols.
*/
if (!(cnt = get_syment_array("root_table", root_tables, 10)))
return 0;
root_table_buf = GETBUF(SIZE(unwind_table));
for (i = found = 0; i < cnt; i++) {
sp = root_tables[i];
if (!readmem(sp->value, KVADDR, root_table_buf,
SIZE(unwind_table), "root unwind_table",
RETURN_ON_ERROR|QUIET))
goto gather_failed;
name = ULONG(root_table_buf + OFFSET(unwind_table_name));
if (read_string(name, buf, strlen("kernel")+1) &&
STREQ("kernel", buf)) {
found++;
if (CRASHDEBUG(1))
fprintf(fp, "root_table name: %lx [%s]\n",
name, buf);
break;
}
}
if (!found)
goto gather_failed;
cnt = populate_local_tables(sp->value, root_table_buf);
FREEBUF(root_table_buf);
return cnt;
gather_failed:
FREEBUF(root_table_buf);
return 0;
}
/*
* Transfer the relevant data from the kernel and module unwind_table
* structures to the local_unwind_table structures.
*/
static int
populate_local_tables(ulong root, char *buf)
{
struct list_data list_data, *ld;
int i, cnt;
ulong *table_list;
ulong vaddr;
struct local_unwind_table *tp;
ld = &list_data;
BZERO(ld, sizeof(struct list_data));
ld->start = root;
ld->member_offset = OFFSET(unwind_table_link);
ld->flags = RETURN_ON_LIST_ERROR;
if (CRASHDEBUG(1))
ld->flags |= VERBOSE;
hq_open();
cnt = do_list(ld);
if (cnt == -1) {
error(WARNING, "UNWIND: failed to gather unwind_table list");
return 0;
}
table_list = (ulong *)GETBUF(cnt * sizeof(ulong));
cnt = retrieve_list(table_list, cnt);
hq_close();
if (!(local_unwind_tables =
malloc(sizeof(struct local_unwind_table) * cnt))) {
error(WARNING, "cannot malloc unwind_table space (%d tables)\n",
cnt);
FREEBUF(table_list);
return 0;
}
for (i = 0; i < cnt; i++, tp++) {
if (!readmem(table_list[i], KVADDR, buf,
SIZE(unwind_table), "unwind_table",
RETURN_ON_ERROR|QUIET)) {
error(WARNING, "cannot read unwind_table\n");
goto failed;
}
tp = &local_unwind_tables[i];
/*
* Copy the required table info for find_table().
*/
BCOPY(buf + OFFSET(unwind_table_core),
(char *)&tp->core.pc, sizeof(ulong)*2);
BCOPY(buf + OFFSET(unwind_table_init),
(char *)&tp->init.pc, sizeof(ulong)*2);
BCOPY(buf + OFFSET(unwind_table_size),
(char *)&tp->size, sizeof(ulong));
/*
* Then read the DWARF CFI data.
*/
vaddr = ULONG(buf + OFFSET(unwind_table_address));
if (!(tp->address = malloc(tp->size))) {
error(WARNING, "cannot malloc unwind_table space\n");
goto failed;
break;
}
if (!readmem(vaddr, KVADDR, tp->address,
tp->size, "DWARF CFI data", RETURN_ON_ERROR|QUIET)) {
error(WARNING, "cannot read unwind_table data\n");
goto failed;
}
}
unwind_tables_cnt = cnt;
if (CRASHDEBUG(7))
dump_local_unwind_tables();
failed:
FREEBUF(table_list);
return unwind_tables_cnt;