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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/delay.h>
#include <linux/stop_machine.h>
#include <asm/sections.h>
#include <asm/uaccess.h>
#include <asm/unaligned.h>
extern char __start_unwind[], __end_unwind[];
#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;
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 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)
{
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;
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);
}
#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);
if (last_table)
|