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/*
*
* Copyright (c) 2016 Samsung Electronics Co., Ltd.
*
* Licensed under the Apache License, Version 2.0 (the License);
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Author: Adrian Szyndela <adrian.s@samsung.com>
*/
/**
* @file crash-stack-arm.c
* @brief unwinding call stacks, functions specific for ARM
*/
#include "crash-stack.h"
#include "wind/unwarm.h"
#include <string.h>
#include <sys/ptrace.h>
#include <sys/user.h>
static Elf *g_core = NULL; ///< core file handler
static Dwfl *g_dwfl = NULL; ///< dwfl handler
static Mappings *g_mappings = NULL; ///< pointer to mappings database
static pid_t g_pid = 0; ///< PID of analyzed program
/**
* @brief Important registers for unwinding stack on ARM
*/
struct Regs {
Dwarf_Addr regs[REGS_REGULAR_NUM]; ///< regular registers
Dwarf_Addr sp; ///< register: stack pointer
Dwarf_Addr lr; ///< register: link register
Dwarf_Addr pc; ///< register: program counter
Dwarf_Addr spsr; ///< register: status register
};
typedef struct Regs Regs; ///< convenience type definition
static Regs g_regs; ///< static storage for target register values
static struct user_regs g_ptrace_registers; ///< static storage for ptrace buffer for registers
void *_crash_stack_get_memory_for_ptrace_registers(size_t *size)
{
if (NULL != size)
*size = sizeof(g_ptrace_registers);
return &g_ptrace_registers;
}
void *_get_place_for_register_value(const char *regname, int regnum)
{
if (strcmp(regname, "pc") == 0 || REG_PC == regnum)
return &g_regs.pc;
else if (strcmp(regname, "sp") == 0 || REG_SP == regnum)
return &g_regs.sp;
else if (strcmp(regname, "lr") == 0 || REG_LR == regnum)
return &g_regs.lr;
else if (strcmp(regname, "spsr") == 0 || REG_SPSR == regnum)
return &g_regs.spsr;
else if (regnum < REGS_REGULAR_NUM)
return &g_regs.regs[regnum];
return NULL;
}
void _crash_stack_set_ptrace_registers(void *regbuf)
{
struct user_regs *registers = regbuf;
int i;
for (i = 0; i < sizeof(registers->uregs)/sizeof(registers->uregs[0]); i++) {
void *regmem = _get_place_for_register_value("", i);
if (NULL != regmem)
memcpy(regmem, ®isters->uregs[i], sizeof(registers->uregs[i]));
}
}
/**
* @brief Callback function for McTernan's unwinder - call stack frame reporting
*
* @param data pointer to call stack database
* @param address return address of the function in the reported call frame
*/
static Boolean __report(void *data, Int32 address)
{
Callstack *callstack = (Callstack *)(data);
callstack->tab[callstack->elems++] = address;
return callstack->elems < MAX_CALLSTACK_LEN ? TRUE : FALSE;
}
/**
* @brief Helper function for reading values from target memory
*
* @param a target address to read from
* @param v destination address to copy data to
* @param size of the value
*/
static Boolean __readT(Int32 a, void *v, size_t size)
{
return _crash_stack_libelf_read_value(g_dwfl, g_core, g_pid, a, v, size, g_mappings);
}
/**
* @brief Callback function for McTernan's unwinder - reading 32 bits
*
* @param a target address to read from
* @param v destination address to copy data to
*/
static Boolean __readW(Int32 a, Int32 *v)
{
return __readT(a, v, sizeof(*v));
}
/**
* @brief Callback function for McTernan's unwinder - reading 16 bits
*
* @param a target address to read from
* @param v destination address to copy data to
*/
static Boolean __readH(Int32 a, Int16 *v)
{
return __readT(a, v, sizeof(*v));
}
/**
* @brief Callback function for McTernan's unwinder - reading 8 bits
*
* @param a target address to read from
* @param v destination address to copy data to
*/
static Boolean __readB(Int32 a, Int8 *v)
{
return __readT(a, v, sizeof(*v));
}
/**
* @brief Callback function for McTernan's unwinder - trying to find function prologue
*
* @param current_pc address from inside of some function from target memory
*/
static Int32 __getProloguePC(Int32 current_pc)
{
return _crash_stack_libelf_get_prologue_pc(g_dwfl, current_pc, g_mappings);
}
void _create_crash_stack(Dwfl *dwfl, Elf *core, pid_t pid, Mappings *mappings, Callstack *callstack)
{
UnwindCallbacks callbacks = {
__report,
__readW,
__readH,
__readB,
__getProloguePC
#ifdef UNW_DEBUG
,
printf
#endif
};
UnwState state;
g_dwfl = dwfl;
g_core = core;
g_mappings = mappings;
g_pid = pid;
callstack->tab[0] = g_regs.pc;
callstack->elems = 1;
UnwInitState(&state, &callbacks, callstack, g_regs.pc, g_regs.sp);
int i;
for (i = 0; i < REGS_REGULAR_NUM; i++) {
state.regData[i].v = g_regs.regs[i];
state.regData[i].o = REG_VAL_FROM_CONST;
}
state.regData[REG_LR].v = g_regs.lr;
state.regData[REG_LR].o = REG_VAL_FROM_STACK;
state.regData[REG_SPSR].v = g_regs.spsr;
state.regData[REG_SPSR].o = REG_VAL_FROM_CONST;
if (UnwIsAddrThumb(g_regs.pc, g_regs.spsr))
UnwStartThumb(&state);
else
UnwStartArm(&state);
}
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