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linux/kernel/unwind.c
Jan Beulich 690a973f48 [PATCH] x86-64: Speed up dwarf2 unwinder 
This changes the dwarf2 unwinder to do a binary search for CIEs
instead of a linear work. The linker is unfortunately not
able to build a proper lookup table at link time, instead it creates
one at runtime as soon as the bootmem allocator is usable (so you'll continue
using the linear lookup for the first [hopefully] few calls).
The code should be ready to utilize a build-time created table once
a fixed linker becomes available.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
2006-10-21 18:37:01 +02:00

1182 lines
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/*
* Copyright (C) 2002-2006 Novell, Inc.
* Jan Beulich <jbeulich@novell.com>
* This code is released under version 2 of the GNU GPL.
*
* A simple API for unwinding kernel stacks. This is used for
* debugging and error reporting purposes. The kernel doesn't need
* full-blown stack unwinding with all the bells and whistles, so there
* is not much point in implementing the full Dwarf2 unwind API.
*/
#include <linux/unwind.h>
#include <linux/module.h>
#include <linux/bootmem.h>
#include <linux/sort.h>
#include <linux/stop_machine.h>
#include <asm/sections.h>
#include <asm/uaccess.h>
#include <asm/unaligned.h>
extern char __start_unwind[], __end_unwind[];
extern const u8 __start_unwind_hdr[], __end_unwind_hdr[];
#define MAX_STACK_DEPTH 8
#define EXTRA_INFO(f) { \
BUILD_BUG_ON_ZERO(offsetof(struct unwind_frame_info, f) \
% FIELD_SIZEOF(struct unwind_frame_info, f)) \
+ offsetof(struct unwind_frame_info, f) \
/ FIELD_SIZEOF(struct unwind_frame_info, f), \
FIELD_SIZEOF(struct unwind_frame_info, f) \
}
#define PTREGS_INFO(f) EXTRA_INFO(regs.f)
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
typedef unsigned long uleb128_t;
typedef signed long sleb128_t;
static struct unwind_table {
struct {
unsigned long pc;
unsigned long range;
} core, init;
const void *address;
unsigned long size;
const unsigned char *header;
unsigned long hdrsz;
struct unwind_table *link;
const char *name;
} root_table;
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 struct unwind_table *find_table(unsigned long pc)
{
struct unwind_table *table;
for (table = &root_table; table; table = table->link)
if ((pc >= table->core.pc
&& pc < table->core.pc + table->core.range)
|| (pc >= table->init.pc
&& pc < table->init.pc + table->init.range))
break;
return table;
}
static unsigned long read_pointer(const u8 **pLoc,
const void *end,
signed ptrType);
static void init_unwind_table(struct unwind_table *table,
const char *name,
const void *core_start,
unsigned long core_size,
const void *init_start,
unsigned long init_size,
const void *table_start,
unsigned long table_size,
const u8 *header_start,
unsigned long header_size)
{
const u8 *ptr = header_start + 4;
const u8 *end = header_start + header_size;
table->core.pc = (unsigned long)core_start;
table->core.range = core_size;
table->init.pc = (unsigned long)init_start;
table->init.range = init_size;
table->address = table_start;
table->size = table_size;
/* See if the linker provided table looks valid. */
if (header_size <= 4
|| header_start[0] != 1
|| (void *)read_pointer(&ptr, end, header_start[1]) != table_start
|| header_start[2] == DW_EH_PE_omit
|| read_pointer(&ptr, end, header_start[2]) <= 0
|| header_start[3] == DW_EH_PE_omit)
header_start = NULL;
table->hdrsz = header_size;
smp_wmb();
table->header = header_start;
table->link = NULL;
table->name = name;
}
void __init unwind_init(void)
{
init_unwind_table(&root_table, "kernel",
_text, _end - _text,
NULL, 0,
__start_unwind, __end_unwind - __start_unwind,
__start_unwind_hdr, __end_unwind_hdr - __start_unwind_hdr);
}
static const u32 bad_cie, not_fde;
static const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *);
static signed fde_pointer_type(const u32 *cie);
struct eh_frame_hdr_table_entry {
unsigned long start, fde;
};
static int cmp_eh_frame_hdr_table_entries(const void *p1, const void *p2)
{
const struct eh_frame_hdr_table_entry *e1 = p1;
const struct eh_frame_hdr_table_entry *e2 = p2;
return (e1->start > e2->start) - (e1->start < e2->start);
}
static void swap_eh_frame_hdr_table_entries(void *p1, void *p2, int size)
{
struct eh_frame_hdr_table_entry *e1 = p1;
struct eh_frame_hdr_table_entry *e2 = p2;
unsigned long v;
v = e1->start;
e1->start = e2->start;
e2->start = v;
v = e1->fde;
e1->fde = e2->fde;
e2->fde = v;
}
static void __init setup_unwind_table(struct unwind_table *table,
void *(*alloc)(unsigned long))
{
const u8 *ptr;
unsigned long tableSize = table->size, hdrSize;
unsigned n;
const u32 *fde;
struct {
u8 version;
u8 eh_frame_ptr_enc;
u8 fde_count_enc;
u8 table_enc;
unsigned long eh_frame_ptr;
unsigned int fde_count;
struct eh_frame_hdr_table_entry table[];
} __attribute__((__packed__)) *header;
if (table->header)
return;
if (table->hdrsz)
printk(KERN_WARNING ".eh_frame_hdr for '%s' present but unusable\n",
table->name);
if (tableSize & (sizeof(*fde) - 1))
return;
for (fde = table->address, n = 0;
tableSize > sizeof(*fde) && tableSize - sizeof(*fde) >= *fde;
tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) {
const u32 *cie = cie_for_fde(fde, table);
signed ptrType;
if (cie == &not_fde)
continue;
if (cie == NULL
|| cie == &bad_cie
|| (ptrType = fde_pointer_type(cie)) < 0)
return;
ptr = (const u8 *)(fde + 2);
if (!read_pointer(&ptr,
(const u8 *)(fde + 1) + *fde,
ptrType))
return;
++n;
}
if (tableSize || !n)
return;
hdrSize = 4 + sizeof(unsigned long) + sizeof(unsigned int)
+ 2 * n * sizeof(unsigned long);
header = alloc(hdrSize);
if (!header)
return;
header->version = 1;
header->eh_frame_ptr_enc = DW_EH_PE_abs|DW_EH_PE_native;
header->fde_count_enc = DW_EH_PE_abs|DW_EH_PE_data4;
header->table_enc = DW_EH_PE_abs|DW_EH_PE_native;
put_unaligned((unsigned long)table->address, &header->eh_frame_ptr);
BUILD_BUG_ON(offsetof(typeof(*header), fde_count)
% __alignof(typeof(header->fde_count)));
header->fde_count = n;
BUILD_BUG_ON(offsetof(typeof(*header), table)
% __alignof(typeof(*header->table)));
for (fde = table->address, tableSize = table->size, n = 0;
tableSize;
tableSize -= sizeof(*fde) + *fde, fde += 1 + *fde / sizeof(*fde)) {
const u32 *cie = fde + 1 - fde[1] / sizeof(*fde);
if (!fde[1])
continue; /* this is a CIE */
ptr = (const u8 *)(fde + 2);
header->table[n].start = read_pointer(&ptr,
(const u8 *)(fde + 1) + *fde,
fde_pointer_type(cie));
header->table[n].fde = (unsigned long)fde;
++n;
}
WARN_ON(n != header->fde_count);
sort(header->table,
n,
sizeof(*header->table),
cmp_eh_frame_hdr_table_entries,
swap_eh_frame_hdr_table_entries);
table->hdrsz = hdrSize;
smp_wmb();
table->header = (const void *)header;
}
static void *__init balloc(unsigned long sz)
{
return __alloc_bootmem_nopanic(sz,
sizeof(unsigned int),
__pa(MAX_DMA_ADDRESS));
}
void __init unwind_setup(void)
{
setup_unwind_table(&root_table, balloc);
}
#ifdef CONFIG_MODULES
static struct unwind_table *last_table;
/* Must be called with module_mutex held. */
void *unwind_add_table(struct module *module,
const void *table_start,
unsigned long table_size)
{
struct unwind_table *table;
if (table_size <= 0)
return NULL;
table = kmalloc(sizeof(*table), GFP_KERNEL);
if (!table)
return NULL;
init_unwind_table(table, module->name,
module->module_core, module->core_size,
module->module_init, module->init_size,
table_start, table_size,
NULL, 0);
if (last_table)
last_table->link = table;
else
root_table.link = table;
last_table = table;
return table;
}
struct unlink_table_info
{
struct unwind_table *table;
int init_only;
};
static int unlink_table(void *arg)
{
struct unlink_table_info *info = arg;
struct unwind_table *table = info->table, *prev;
for (prev = &root_table; prev->link && prev->link != table; prev = prev->link)
;
if (prev->link) {
if (info->init_only) {
table->init.pc = 0;
table->init.range = 0;
info->table = NULL;
} else {
prev->link = table->link;
if (!prev->link)
last_table = prev;
}
} else
info->table = NULL;
return 0;
}
/* Must be called with module_mutex held. */
void unwind_remove_table(void *handle, int init_only)
{
struct unwind_table *table = handle;
struct unlink_table_info info;
if (!table || table == &root_table)
return;
if (init_only && table == last_table) {
table->init.pc = 0;
table->init.range = 0;
return;
}
info.table = table;
info.init_only = init_only;
stop_machine_run(unlink_table, &info, NR_CPUS);
if (info.table)
kfree(table);
}
#endif /* CONFIG_MODULES */
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 const u32 *cie_for_fde(const u32 *fde, const struct unwind_table *table)
{
const u32 *cie;
if (!*fde || (*fde & (sizeof(*fde) - 1)))
return &bad_cie;
if (!fde[1])
return &not_fde; /* this is a CIE */
if ((fde[1] & (sizeof(*fde) - 1))
|| fde[1] > (unsigned long)(fde + 1) - (unsigned long)table->address)
return NULL; /* this is not a valid FDE */
cie = fde + 1 - fde[1] / sizeof(*fde);
if (*cie <= sizeof(*cie) + 4
|| *cie >= fde[1] - sizeof(*fde)
|| (*cie & (sizeof(*cie) - 1))
|| cie[1])
return NULL; /* this is not a (valid) CIE */
return cie;
}
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;
}
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)
{
#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 pc = UNW_PC(frame) - frame->call_frame;
unsigned long startLoc = 0, endLoc = 0, cfa;
unsigned i;
signed ptrType = -1;
uleb128_t retAddrReg = 0;
const struct unwind_table *table;
struct unwind_state state;
if (UNW_PC(frame) == 0)
return -EINVAL;
if ((table = find_table(pc)) != NULL
&& !(table->size & (sizeof(*fde) - 1))) {
const u8 *hdr = table->header;
unsigned long tableSize;
smp_rmb();
if (hdr && hdr[0] == 1) {
switch(hdr[3] & DW_EH_PE_FORM) {
case DW_EH_PE_native: tableSize = sizeof(unsigned long); break;
case DW_EH_PE_data2: tableSize = 2; break;
case DW_EH_PE_data4: tableSize = 4; break;
case DW_EH_PE_data8: tableSize = 8; break;
default: tableSize = 0; break;
}
ptr = hdr + 4;
end = hdr + table->hdrsz;
if (tableSize
&& read_pointer(&ptr, end, hdr[1])
== (unsigned long)table->address
&& (i = read_pointer(&ptr, end, hdr[2])) > 0
&& i == (end - ptr) / (2 * tableSize)
&& !((end - ptr) % (2 * tableSize))) {
do {
const u8 *cur = ptr + (i / 2) * (2 * tableSize);
startLoc = read_pointer(&cur,
cur + tableSize,
hdr[3]);
if (pc < startLoc)
i /= 2;
else {
ptr = cur - tableSize;
i = (i + 1) / 2;
}
} while (startLoc && i > 1);
if (i == 1
&& (startLoc = read_pointer(&ptr,
ptr + tableSize,
hdr[3])) != 0
&& pc >= startLoc)
fde = (void *)read_pointer(&ptr,
ptr + tableSize,
hdr[3]);
}
}
if (fde != NULL) {
cie = cie_for_fde(fde, table);
ptr = (const u8 *)(fde + 2);
if(cie != NULL
&& cie != &bad_cie
&& cie != &not_fde
&& (ptrType = fde_pointer_type(cie)) >= 0
&& read_pointer(&ptr,
(const u8 *)(fde + 1) + *fde,
ptrType) == startLoc) {
if (!(ptrType & DW_EH_PE_indirect))
ptrType &= DW_EH_PE_FORM|DW_EH_PE_signed;
endLoc = startLoc
+ read_pointer(&ptr,
(const u8 *)(fde + 1) + *fde,
ptrType);
if(pc >= endLoc)
fde = NULL;
} else
fde = NULL;
}
if (fde == NULL) {
for (fde = table->address, tableSize = table->size;
cie = NULL, tableSize > sizeof(*fde)
&& tableSize - sizeof(*fde) >= *fde;
tableSize -= sizeof(*fde) + *fde,
fde += 1 + *fde / sizeof(*fde)) {
cie = cie_for_fde(fde, table);
if (cie == &bad_cie) {
cie = NULL;
break;
}
if (cie == NULL
|| cie == &not_fde
|| (ptrType = fde_pointer_type(cie)) < 0)
continue;
ptr = (const u8 *)(fde + 2);
startLoc = read_pointer(&ptr,
(const u8 *)(fde + 1) + *fde,
ptrType);
if (!startLoc)
continue;
if (!(ptrType & DW_EH_PE_indirect))
ptrType &= DW_EH_PE_FORM|DW_EH_PE_signed;
endLoc = startLoc
+ read_pointer(&ptr,
(const u8 *)(fde + 1) + *fde,
ptrType);
if (pc >= startLoc && pc < endLoc)
break;
}
}
}
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;
frame->call_frame = 1;
if ((state.version = *ptr) != 1)
cie = NULL; /* unsupported version */
else if (*++ptr) {
/* check if augmentation size is first (and thus present) */
if (*ptr == 'z') {
while (++ptr < end && *ptr) {
switch(*ptr) {
/* check for ignorable (or already handled)
* nul-terminated augmentation string */
case 'L':
case 'P':
case 'R':
continue;
case 'S':
frame->call_frame = 0;
continue;
default:
break;
}
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) {
#ifdef CONFIG_FRAME_POINTER
unsigned long top, bottom;
#endif
#ifdef CONFIG_FRAME_POINTER
top = STACK_TOP(frame->task);
bottom = STACK_BOTTOM(frame->task);
# if FRAME_RETADDR_OFFSET < 0
if (UNW_SP(frame) < top
&& UNW_FP(frame) <= UNW_SP(frame)
&& bottom < UNW_FP(frame)
# else
if (UNW_SP(frame) > top
&& UNW_FP(frame) >= UNW_SP(frame)
&& bottom > UNW_FP(frame)
# endif
&& !((UNW_SP(frame) | UNW_FP(frame))
& (sizeof(unsigned long) - 1))) {
unsigned long link;
if (!__get_user(link,
(unsigned long *)(UNW_FP(frame)
+ FRAME_LINK_OFFSET))
# if FRAME_RETADDR_OFFSET < 0
&& link > bottom && link < UNW_FP(frame)
# else
&& link > UNW_FP(frame) && link < bottom
# endif
&& !(link & (sizeof(link) - 1))
&& !__get_user(UNW_PC(frame),
(unsigned long *)(UNW_FP(frame)
+ FRAME_RETADDR_OFFSET))) {
UNW_SP(frame) = UNW_FP(frame) + FRAME_RETADDR_OFFSET
# if FRAME_RETADDR_OFFSET < 0
-
# else
+
# endif
sizeof(UNW_PC(frame));
UNW_FP(frame) = link;
return 0;
}
}
#endif
return -ENXIO;
}
state.org = startLoc;
memcpy(&state.cfa, &badCFA, sizeof(state.cfa));
/* process instructions */
if (!processCFI(ptr, end, pc, 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 */
#ifndef CONFIG_AS_CFI_SIGNAL_FRAME
if(frame->call_frame
&& !UNW_DEFAULT_RA(state.regs[retAddrReg], state.dataAlign))
frame->call_frame = 0;
#endif
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): \
__get_user(FRAME_REG(i, u##n), (u##n *)addr); \
break
CASES;
#undef CASE
default:
return -EIO;
}
}
break;
}
}
return 0;
#undef CASES
#undef FRAME_REG
}
EXPORT_SYMBOL(unwind);
int unwind_init_frame_info(struct unwind_frame_info *info,
struct task_struct *tsk,
/*const*/ struct pt_regs *regs)
{
info->task = tsk;
info->call_frame = 0;
arch_unw_init_frame_info(info, regs);
return 0;
}
EXPORT_SYMBOL(unwind_init_frame_info);
/*
* Prepare to unwind a blocked task.
*/
int unwind_init_blocked(struct unwind_frame_info *info,
struct task_struct *tsk)
{
info->task = tsk;
info->call_frame = 0;
arch_unw_init_blocked(info);
return 0;
}
EXPORT_SYMBOL(unwind_init_blocked);
/*
* Prepare to unwind the currently running thread.
*/
int unwind_init_running(struct unwind_frame_info *info,
asmlinkage int (*callback)(struct unwind_frame_info *,
void *arg),
void *arg)
{
info->task = current;
info->call_frame = 0;
return arch_unwind_init_running(info, callback, arg);
}
EXPORT_SYMBOL(unwind_init_running);
/*
* Unwind until the return pointer is in user-land (or until an error
* occurs). Returns 0 if successful, negative number in case of
* error.
*/
int unwind_to_user(struct unwind_frame_info *info)
{
while (!arch_unw_user_mode(info)) {
int err = unwind(info);
if (err < 0)
return err;
}
return 0;
}
EXPORT_SYMBOL(unwind_to_user);
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