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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 <string.h>
#include <functional>
#if defined(__BIONIC__)
#include <bionic/pac.h>
#endif
#include <unwindstack/Elf.h>
#include <unwindstack/MachineArm64.h>
#include <unwindstack/MapInfo.h>
#include <unwindstack/Memory.h>
#include <unwindstack/RegsArm64.h>
#include <unwindstack/UcontextArm64.h>
#include <unwindstack/UserArm64.h>
namespace unwindstack {
RegsArm64::RegsArm64()
: RegsImpl<uint64_t>(ARM64_REG_LAST, Location(LOCATION_REGISTER, ARM64_REG_LR)) {
ResetPseudoRegisters();
pac_mask_ = 0;
}
ArchEnum RegsArm64::Arch() {
return ARCH_ARM64;
}
uint64_t RegsArm64::pc() {
return regs_[ARM64_REG_PC];
}
uint64_t RegsArm64::sp() {
return regs_[ARM64_REG_SP];
}
static uint64_t strip_pac(uint64_t pc, uint64_t mask) {
// If the target is aarch64 then the return address may have been
// signed using the Armv8.3-A Pointer Authentication extension. The
// original return address can be restored by stripping out the
// authentication code using a mask or xpaclri. xpaclri is a NOP on
// pre-Armv8.3-A architectures.
if (mask) {
pc &= ~mask;
} else {
#if defined(__BIONIC__)
pc = __bionic_clear_pac_bits(pc);
#endif
}
return pc;
}
void RegsArm64::set_pc(uint64_t pc) {
if ((0 != pc) && IsRASigned()) {
pc = strip_pac(pc, pac_mask_);
}
regs_[ARM64_REG_PC] = pc;
}
void RegsArm64::set_sp(uint64_t sp) {
regs_[ARM64_REG_SP] = sp;
}
void RegsArm64::fallback_pc() {
// As a last resort, try stripping the PC of the pointer
// authentication code.
regs_[ARM64_REG_PC] = strip_pac(regs_[ARM64_REG_PC], pac_mask_);
}
bool RegsArm64::SetPcFromReturnAddress(Memory*) {
uint64_t lr = regs_[ARM64_REG_LR];
if (regs_[ARM64_REG_PC] == lr) {
return false;
}
regs_[ARM64_REG_PC] = lr;
return true;
}
void RegsArm64::IterateRegisters(std::function<void(const char*, uint64_t)> fn) {
fn("x0", regs_[ARM64_REG_R0]);
fn("x1", regs_[ARM64_REG_R1]);
fn("x2", regs_[ARM64_REG_R2]);
fn("x3", regs_[ARM64_REG_R3]);
fn("x4", regs_[ARM64_REG_R4]);
fn("x5", regs_[ARM64_REG_R5]);
fn("x6", regs_[ARM64_REG_R6]);
fn("x7", regs_[ARM64_REG_R7]);
fn("x8", regs_[ARM64_REG_R8]);
fn("x9", regs_[ARM64_REG_R9]);
fn("x10", regs_[ARM64_REG_R10]);
fn("x11", regs_[ARM64_REG_R11]);
fn("x12", regs_[ARM64_REG_R12]);
fn("x13", regs_[ARM64_REG_R13]);
fn("x14", regs_[ARM64_REG_R14]);
fn("x15", regs_[ARM64_REG_R15]);
fn("x16", regs_[ARM64_REG_R16]);
fn("x17", regs_[ARM64_REG_R17]);
fn("x18", regs_[ARM64_REG_R18]);
fn("x19", regs_[ARM64_REG_R19]);
fn("x20", regs_[ARM64_REG_R20]);
fn("x21", regs_[ARM64_REG_R21]);
fn("x22", regs_[ARM64_REG_R22]);
fn("x23", regs_[ARM64_REG_R23]);
fn("x24", regs_[ARM64_REG_R24]);
fn("x25", regs_[ARM64_REG_R25]);
fn("x26", regs_[ARM64_REG_R26]);
fn("x27", regs_[ARM64_REG_R27]);
fn("x28", regs_[ARM64_REG_R28]);
fn("x29", regs_[ARM64_REG_R29]);
fn("lr", regs_[ARM64_REG_LR]);
fn("sp", regs_[ARM64_REG_SP]);
fn("pc", regs_[ARM64_REG_PC]);
fn("pst", regs_[ARM64_REG_PSTATE]);
}
Regs* RegsArm64::Read(void* remote_data) {
arm64_user_regs* user = reinterpret_cast<arm64_user_regs*>(remote_data);
RegsArm64* regs = new RegsArm64();
memcpy(regs->RawData(), &user->regs[0], (ARM64_REG_R30 + 1) * sizeof(uint64_t));
uint64_t* reg_data = reinterpret_cast<uint64_t*>(regs->RawData());
reg_data[ARM64_REG_SP] = user->sp;
reg_data[ARM64_REG_PC] = user->pc;
reg_data[ARM64_REG_PSTATE] = user->pstate;
return regs;
}
Regs* RegsArm64::CreateFromUcontext(void* ucontext) {
arm64_ucontext_t* arm64_ucontext = reinterpret_cast<arm64_ucontext_t*>(ucontext);
RegsArm64* regs = new RegsArm64();
memcpy(regs->RawData(), &arm64_ucontext->uc_mcontext.regs[0], ARM64_REG_LAST * sizeof(uint64_t));
return regs;
}
bool RegsArm64::StepIfSignalHandler(uint64_t elf_offset, Elf* elf, Memory* process_memory) {
uint64_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(elf_offset, &data, sizeof(data))) {
return false;
}
// Look for the kernel sigreturn function.
// __kernel_rt_sigreturn:
// 0xd2801168 mov x8, #0x8b
// 0xd4000001 svc #0x0
if (data != 0xd4000001d2801168ULL) {
return false;
}
// SP + sizeof(siginfo_t) + uc_mcontext offset + X0 offset.
if (!process_memory->ReadFully(regs_[ARM64_REG_SP] + 0x80 + 0xb0 + 0x08, regs_.data(),
sizeof(uint64_t) * ARM64_REG_LAST)) {
return false;
}
return true;
}
void RegsArm64::ResetPseudoRegisters(void) {
// DWARF for AArch64 says RA_SIGN_STATE should be initialized to 0.
this->SetPseudoRegister(Arm64Reg::ARM64_PREG_RA_SIGN_STATE, 0);
}
bool RegsArm64::SetPseudoRegister(uint16_t id, uint64_t value) {
if ((id >= Arm64Reg::ARM64_PREG_FIRST) && (id < Arm64Reg::ARM64_PREG_LAST)) {
pseudo_regs_[id - Arm64Reg::ARM64_PREG_FIRST] = value;
return true;
}
return false;
}
bool RegsArm64::GetPseudoRegister(uint16_t id, uint64_t* value) {
if ((id >= Arm64Reg::ARM64_PREG_FIRST) && (id < Arm64Reg::ARM64_PREG_LAST)) {
*value = pseudo_regs_[id - Arm64Reg::ARM64_PREG_FIRST];
return true;
}
return false;
}
bool RegsArm64::IsRASigned() {
uint64_t value;
auto result = this->GetPseudoRegister(Arm64Reg::ARM64_PREG_RA_SIGN_STATE, &value);
return (result && (value != 0));
}
void RegsArm64::SetPACMask(uint64_t mask) {
pac_mask_ = mask;
}
Regs* RegsArm64::Clone() {
return new RegsArm64(*this);
}
} // namespace unwindstack
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