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/*
* Copyright (C) 2016 The Android Open Source Project
*
* 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.
*/
#include <stdint.h>
#include <functional>
#include <unwindstack/Elf.h>
#include <unwindstack/MapInfo.h>
#include <unwindstack/Memory.h>
#include <unwindstack/RegsArm.h>
#include "MachineArm.h"
#include "UcontextArm.h"
#include "UserArm.h"
namespace unwindstack {
RegsArm::RegsArm()
: RegsImpl<uint32_t>(ARM_REG_LAST, ARM_REG_SP, Location(LOCATION_REGISTER, ARM_REG_LR)) {}
ArchEnum RegsArm::Arch() {
return ARCH_ARM;
}
uint64_t RegsArm::GetAdjustedPc(uint64_t rel_pc, Elf* elf) {
if (!elf->valid()) {
return rel_pc;
}
uint64_t load_bias = elf->GetLoadBias();
if (rel_pc < load_bias) {
return rel_pc;
}
uint64_t adjusted_rel_pc = rel_pc - load_bias;
if (adjusted_rel_pc < 5) {
return rel_pc;
}
if (adjusted_rel_pc & 1) {
// This is a thumb instruction, it could be 2 or 4 bytes.
uint32_t value;
if (rel_pc < 5 || !elf->memory()->ReadFully(adjusted_rel_pc - 5, &value, sizeof(value)) ||
(value & 0xe000f000) != 0xe000f000) {
return rel_pc - 2;
}
}
return rel_pc - 4;
}
void RegsArm::SetFromRaw() {
set_pc(regs_[ARM_REG_PC]);
set_sp(regs_[ARM_REG_SP]);
}
bool RegsArm::SetPcFromReturnAddress(Memory*) {
if (pc() == regs_[ARM_REG_LR]) {
return false;
}
set_pc(regs_[ARM_REG_LR]);
return true;
}
void RegsArm::IterateRegisters(std::function<void(const char*, uint64_t)> fn) {
fn("r0", regs_[ARM_REG_R0]);
fn("r1", regs_[ARM_REG_R1]);
fn("r2", regs_[ARM_REG_R2]);
fn("r3", regs_[ARM_REG_R3]);
fn("r4", regs_[ARM_REG_R4]);
fn("r5", regs_[ARM_REG_R5]);
fn("r6", regs_[ARM_REG_R6]);
fn("r7", regs_[ARM_REG_R7]);
fn("r8", regs_[ARM_REG_R8]);
fn("r9", regs_[ARM_REG_R9]);
fn("r10", regs_[ARM_REG_R10]);
fn("r11", regs_[ARM_REG_R11]);
fn("ip", regs_[ARM_REG_R12]);
fn("sp", regs_[ARM_REG_SP]);
fn("lr", regs_[ARM_REG_LR]);
fn("pc", regs_[ARM_REG_PC]);
}
Regs* RegsArm::Read(void* remote_data) {
arm_user_regs* user = reinterpret_cast<arm_user_regs*>(remote_data);
RegsArm* regs = new RegsArm();
memcpy(regs->RawData(), &user->regs[0], ARM_REG_LAST * sizeof(uint32_t));
regs->SetFromRaw();
return regs;
}
Regs* RegsArm::CreateFromUcontext(void* ucontext) {
arm_ucontext_t* arm_ucontext = reinterpret_cast<arm_ucontext_t*>(ucontext);
RegsArm* regs = new RegsArm();
memcpy(regs->RawData(), &arm_ucontext->uc_mcontext.regs[0], ARM_REG_LAST * sizeof(uint32_t));
regs->SetFromRaw();
return regs;
}
bool RegsArm::StepIfSignalHandler(uint64_t rel_pc, Elf* elf, Memory* process_memory) {
uint32_t data;
Memory* elf_memory = elf->memory();
// Read from elf memory since it is usually more expensive to read from
// process memory.
if (!elf_memory->ReadFully(rel_pc, &data, sizeof(data))) {
return false;
}
uint64_t offset = 0;
if (data == 0xe3a07077 || data == 0xef900077 || data == 0xdf002777) {
// non-RT sigreturn call.
// __restore:
//
// Form 1 (arm):
// 0x77 0x70 mov r7, #0x77
// 0xa0 0xe3 svc 0x00000000
//
// Form 2 (arm):
// 0x77 0x00 0x90 0xef svc 0x00900077
//
// Form 3 (thumb):
// 0x77 0x27 movs r7, #77
// 0x00 0xdf svc 0
if (!process_memory->ReadFully(sp(), &data, sizeof(data))) {
return false;
}
if (data == 0x5ac3c35a) {
// SP + uc_mcontext offset + r0 offset.
offset = sp() + 0x14 + 0xc;
} else {
// SP + r0 offset
offset = sp() + 0xc;
}
} else if (data == 0xe3a070ad || data == 0xef9000ad || data == 0xdf0027ad) {
// RT sigreturn call.
// __restore_rt:
//
// Form 1 (arm):
// 0xad 0x70 mov r7, #0xad
// 0xa0 0xe3 svc 0x00000000
//
// Form 2 (arm):
// 0xad 0x00 0x90 0xef svc 0x009000ad
//
// Form 3 (thumb):
// 0xad 0x27 movs r7, #ad
// 0x00 0xdf svc 0
if (!process_memory->ReadFully(sp(), &data, sizeof(data))) {
return false;
}
if (data == sp() + 8) {
// SP + 8 + sizeof(siginfo_t) + uc_mcontext_offset + r0 offset
offset = sp() + 8 + 0x80 + 0x14 + 0xc;
} else {
// SP + sizeof(siginfo_t) + uc_mcontext_offset + r0 offset
offset = sp() + 0x80 + 0x14 + 0xc;
}
}
if (offset == 0) {
return false;
}
if (!process_memory->ReadFully(offset, regs_.data(), sizeof(uint32_t) * ARM_REG_LAST)) {
return false;
}
SetFromRaw();
return true;
}
} // namespace unwindstack