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citra/src/core/gdbstub/gdbstub.cpp

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// Copyright 2013 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.
// Originally written by Sven Peter <sven@fail0verflow.com> for anergistic.
#include <algorithm>
#include <atomic>
#include <climits>
#include <csignal>
#include <cstdarg>
#include <cstdio>
#include <cstring>
#include <map>
#include <numeric>
#include <fcntl.h>
#include <fmt/format.h>
#ifdef _WIN32
#include <winsock2.h>
// winsock2.h needs to be included first to prevent winsock.h being included by other includes
#include <io.h>
#include <iphlpapi.h>
#include <ws2tcpip.h>
#define SHUT_RDWR 2
#else
#include <netinet/in.h>
#include <sys/select.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
#endif
#include "common/logging/log.h"
#include "core/arm/arm_interface.h"
#include "core/core.h"
#include "core/gdbstub/gdbstub.h"
#include "core/hle/kernel/process.h"
#include "core/loader/loader.h"
#include "core/memory.h"
namespace GDBStub {
namespace {
constexpr int GDB_BUFFER_SIZE = 10000;
constexpr char GDB_STUB_START = '$';
constexpr char GDB_STUB_END = '#';
constexpr char GDB_STUB_ACK = '+';
constexpr char GDB_STUB_NACK = '-';
#ifndef SIGTRAP
constexpr u32 SIGTRAP = 5;
#endif
#ifndef SIGTERM
constexpr u32 SIGTERM = 15;
#endif
#ifndef MSG_WAITALL
constexpr u32 MSG_WAITALL = 8;
#endif
constexpr u32 SP_REGISTER = 13;
constexpr u32 LR_REGISTER = 14;
constexpr u32 PC_REGISTER = 15;
constexpr u32 CPSR_REGISTER = 25;
constexpr u32 D0_REGISTER = 26;
constexpr u32 FPSCR_REGISTER = 42;
// For sample XML files see the GDB source /gdb/features
// GDB also wants the l character at the start
// This XML defines what the registers are for this specific ARM device
constexpr char target_xml[] =
R"(l<?xml version="1.0"?>
<!DOCTYPE target SYSTEM "gdb-target.dtd">
<target version="1.0">
<feature name="org.gnu.gdb.arm.core">
<reg name="r0" bitsize="32"/>
<reg name="r1" bitsize="32"/>
<reg name="r2" bitsize="32"/>
<reg name="r3" bitsize="32"/>
<reg name="r4" bitsize="32"/>
<reg name="r5" bitsize="32"/>
<reg name="r6" bitsize="32"/>
<reg name="r7" bitsize="32"/>
<reg name="r8" bitsize="32"/>
<reg name="r9" bitsize="32"/>
<reg name="r10" bitsize="32"/>
<reg name="r11" bitsize="32"/>
<reg name="r12" bitsize="32"/>
<reg name="sp" bitsize="32" type="data_ptr"/>
<reg name="lr" bitsize="32"/>
<reg name="pc" bitsize="32" type="code_ptr"/>
<!-- The CPSR is register 25, rather than register 16, because
the FPA registers historically were placed between the PC
and the CPSR in the "g" packet. -->
<reg name="cpsr" bitsize="32" regnum="25"/>
</feature>
<feature name="org.gnu.gdb.arm.vfp">
<reg name="d0" bitsize="64" type="float"/>
<reg name="d1" bitsize="64" type="float"/>
<reg name="d2" bitsize="64" type="float"/>
<reg name="d3" bitsize="64" type="float"/>
<reg name="d4" bitsize="64" type="float"/>
<reg name="d5" bitsize="64" type="float"/>
<reg name="d6" bitsize="64" type="float"/>
<reg name="d7" bitsize="64" type="float"/>
<reg name="d8" bitsize="64" type="float"/>
<reg name="d9" bitsize="64" type="float"/>
<reg name="d10" bitsize="64" type="float"/>
<reg name="d11" bitsize="64" type="float"/>
<reg name="d12" bitsize="64" type="float"/>
<reg name="d13" bitsize="64" type="float"/>
<reg name="d14" bitsize="64" type="float"/>
<reg name="d15" bitsize="64" type="float"/>
<reg name="fpscr" bitsize="32" type="int" group="float"/>
</feature>
</target>
)";
int gdbserver_socket = -1;
bool defer_start = false;
u8 command_buffer[GDB_BUFFER_SIZE];
u32 command_length;
u32 latest_signal = 0;
bool memory_break = false;
static Kernel::Thread* current_thread = nullptr;
// Binding to a port within the reserved ports range (0-1023) requires root permissions,
// so default to a port outside of that range.
u16 gdbstub_port = 24689;
bool halt_loop = true;
bool step_loop = false;
bool send_trap = false;
// If set to false, the server will never be started and no
// gdbstub-related functions will be executed.
std::atomic<bool> server_enabled(false);
#ifdef _WIN32
WSADATA InitData;
#endif
struct Breakpoint {
bool active;
VAddr addr;
u32 len;
std::array<u8, 4> inst;
};
using BreakpointMap = std::map<VAddr, Breakpoint>;
BreakpointMap breakpoints_execute;
BreakpointMap breakpoints_read;
BreakpointMap breakpoints_write;
} // Anonymous namespace
static Kernel::Thread* FindThreadById(int id) {
u32 num_cores = Core::GetNumCores();
for (u32 i = 0; i < num_cores; ++i) {
const auto& threads =
Core::System::GetInstance().Kernel().GetThreadManager(i).GetThreadList();
for (auto& thread : threads) {
if (thread->GetThreadId() == static_cast<u32>(id)) {
return thread.get();
}
}
}
return nullptr;
}
static u32 RegRead(std::size_t id, Kernel::Thread* thread = nullptr) {
if (!thread) {
return 0;
}
if (id <= PC_REGISTER) {
return thread->context->GetCpuRegister(id);
} else if (id == CPSR_REGISTER) {
return thread->context->GetCpsr();
} else {
return 0;
}
}
static void RegWrite(std::size_t id, u32 val, Kernel::Thread* thread = nullptr) {
if (!thread) {
return;
}
if (id <= PC_REGISTER) {
return thread->context->SetCpuRegister(id, val);
} else if (id == CPSR_REGISTER) {
return thread->context->SetCpsr(val);
}
}
static u64 FpuRead(std::size_t id, Kernel::Thread* thread = nullptr) {
if (!thread) {
return 0;
}
if (id >= D0_REGISTER && id < FPSCR_REGISTER) {
u64 ret = thread->context->GetFpuRegister(2 * (id - D0_REGISTER));
ret |= static_cast<u64>(thread->context->GetFpuRegister(2 * (id - D0_REGISTER) + 1)) << 32;
return ret;
} else if (id == FPSCR_REGISTER) {
return thread->context->GetFpscr();
} else {
return 0;
}
}
static void FpuWrite(std::size_t id, u64 val, Kernel::Thread* thread = nullptr) {
if (!thread) {
return;
}
if (id >= D0_REGISTER && id < FPSCR_REGISTER) {
thread->context->SetFpuRegister(2 * (id - D0_REGISTER), static_cast<u32>(val));
thread->context->SetFpuRegister(2 * (id - D0_REGISTER) + 1, static_cast<u32>(val >> 32));
} else if (id == FPSCR_REGISTER) {
return thread->context->SetFpscr(static_cast<u32>(val));
}
}
/**
* Turns hex string character into the equivalent byte.
*
* @param hex Input hex character to be turned into byte.
*/
static u8 HexCharToValue(u8 hex) {
if (hex >= '0' && hex <= '9') {
return hex - '0';
} else if (hex >= 'a' && hex <= 'f') {
return hex - 'a' + 0xA;
} else if (hex >= 'A' && hex <= 'F') {
return hex - 'A' + 0xA;
}
LOG_ERROR(Debug_GDBStub, "Invalid nibble: {:c} {:02x}\n", hex, hex);
return 0;
}
/**
* Turn nibble of byte into hex string character.
*
* @param n Nibble to be turned into hex character.
*/
static u8 NibbleToHex(u8 n) {
n &= 0xF;
if (n < 0xA) {
return '0' + n;
} else {
return 'a' + n - 0xA;
}
}
/**
* Converts input hex string characters into an array of equivalent of u8 bytes.
*
* @param src Pointer to array of output hex string characters.
* @param len Length of src array.
*/
static u32 HexToInt(const u8* src, std::size_t len) {
u32 output = 0;
while (len-- > 0) {
output = (output << 4) | HexCharToValue(src[0]);
src++;
}
return output;
}
/**
* Converts input array of u8 bytes into their equivalent hex string characters.
*
* @param dest Pointer to buffer to store output hex string characters.
* @param src Pointer to array of u8 bytes.
* @param len Length of src array.
*/
static void MemToGdbHex(u8* dest, const u8* src, std::size_t len) {
while (len-- > 0) {
u8 tmp = *src++;
*dest++ = NibbleToHex(tmp >> 4);
*dest++ = NibbleToHex(tmp);
}
}
/**
* Converts input gdb-formatted hex string characters into an array of equivalent of u8 bytes.
*
* @param dest Pointer to buffer to store u8 bytes.
* @param src Pointer to array of output hex string characters.
* @param len Length of src array.
*/
static void GdbHexToMem(u8* dest, const u8* src, std::size_t len) {
while (len-- > 0) {
*dest++ = (HexCharToValue(src[0]) << 4) | HexCharToValue(src[1]);
src += 2;
}
}
/**
* Convert a u32 into a gdb-formatted hex string.
*
* @param dest Pointer to buffer to store output hex string characters.
* @param v Value to convert.
*/
static void IntToGdbHex(u8* dest, u32 v) {
for (int i = 0; i < 8; i += 2) {
dest[i + 1] = NibbleToHex(v >> (4 * i));
dest[i] = NibbleToHex(v >> (4 * (i + 1)));
}
}
/**
* Convert a gdb-formatted hex string into a u32.
*
* @param src Pointer to hex string.
*/
static u32 GdbHexToInt(const u8* src) {
u32 output = 0;
for (int i = 0; i < 8; i += 2) {
output = (output << 4) | HexCharToValue(src[7 - i - 1]);
output = (output << 4) | HexCharToValue(src[7 - i]);
}
return output;
}
/**
* Convert a u64 into a gdb-formatted hex string.
*
* @param dest Pointer to buffer to store output hex string characters.
* @param v Value to convert.
*/
static void LongToGdbHex(u8* dest, u64 v) {
for (int i = 0; i < 16; i += 2) {
dest[i + 1] = NibbleToHex(static_cast<u8>(v >> (4 * i)));
dest[i] = NibbleToHex(static_cast<u8>(v >> (4 * (i + 1))));
}
}
/**
* Convert a gdb-formatted hex string into a u64.
*
* @param src Pointer to hex string.
*/
static u64 GdbHexToLong(const u8* src) {
u64 output = 0;
for (int i = 0; i < 16; i += 2) {
output = (output << 4) | HexCharToValue(src[15 - i - 1]);
output = (output << 4) | HexCharToValue(src[15 - i]);
}
return output;
}
/// Read a byte from the gdb client.
static u8 ReadByte() {
u8 c;
std::size_t received_size = recv(gdbserver_socket, reinterpret_cast<char*>(&c), 1, MSG_WAITALL);
if (received_size != 1) {
LOG_ERROR(Debug_GDBStub, "recv failed : {}", received_size);
Shutdown();
}
return c;
}
/// Calculate the checksum of the current command buffer.
static u8 CalculateChecksum(const u8* buffer, std::size_t length) {
return static_cast<u8>(std::accumulate(buffer, buffer + length, 0, std::plus<u8>()));
}
/**
* Get the map of breakpoints for a given breakpoint type.
*
* @param type Type of breakpoint map.
*/
static BreakpointMap& GetBreakpointMap(BreakpointType type) {
switch (type) {
case BreakpointType::Execute:
return breakpoints_execute;
case BreakpointType::Read:
return breakpoints_read;
case BreakpointType::Write:
return breakpoints_write;
default:
return breakpoints_read;
}
}
/**
* Remove the breakpoint from the given address of the specified type.
*
* @param type Type of breakpoint.
* @param addr Address of breakpoint.
*/
static void RemoveBreakpoint(BreakpointType type, VAddr addr) {
BreakpointMap& p = GetBreakpointMap(type);
const auto bp = p.find(addr);
if (bp == p.end()) {
return;
}
LOG_DEBUG(Debug_GDBStub, "gdb: removed a breakpoint: {:08x} bytes at {:08x} of type {}",
bp->second.len, bp->second.addr, type);
if (type == BreakpointType::Execute) {
Core::System::GetInstance().Memory().WriteBlock(
*Core::System::GetInstance().Kernel().GetCurrentProcess(), bp->second.addr,
bp->second.inst.data(), bp->second.inst.size());
u32 num_cores = Core::GetNumCores();
for (u32 i = 0; i < num_cores; ++i) {
Core::GetCore(i).ClearInstructionCache();
}
}
p.erase(addr);
}
BreakpointAddress GetNextBreakpointFromAddress(VAddr addr, BreakpointType type) {
const BreakpointMap& p = GetBreakpointMap(type);
const auto next_breakpoint = p.lower_bound(addr);
BreakpointAddress breakpoint;
if (next_breakpoint != p.end()) {
breakpoint.address = next_breakpoint->first;
breakpoint.type = type;
} else {
breakpoint.address = 0;
breakpoint.type = BreakpointType::None;
}
return breakpoint;
}
bool CheckBreakpoint(VAddr addr, BreakpointType type) {
if (!IsConnected()) {
return false;
}
const BreakpointMap& p = GetBreakpointMap(type);
const auto bp = p.find(addr);
if (bp == p.end()) {
return false;
}
u32 len = bp->second.len;
// IDA Pro defaults to 4-byte breakpoints for all non-hardware breakpoints
// no matter if it's a 4-byte or 2-byte instruction. When you execute a
// Thumb instruction with a 4-byte breakpoint set, it will set a breakpoint on
// two instructions instead of the single instruction you placed the breakpoint
// on. So, as a way to make sure that execution breakpoints are only breaking
// on the instruction that was specified, set the length of an execution
// breakpoint to 1. This should be fine since the CPU should never begin executing
// an instruction anywhere except the beginning of the instruction.
if (type == BreakpointType::Execute) {
len = 1;
}
if (bp->second.active && (addr >= bp->second.addr && addr < bp->second.addr + len)) {
LOG_DEBUG(Debug_GDBStub,
"Found breakpoint type {} @ {:08x}, range: {:08x}"
" - {:08x} ({:x} bytes)",
type, addr, bp->second.addr, bp->second.addr + len, len);
return true;
}
return false;
}
/**
* Send packet to gdb client.
*
* @param packet Packet to be sent to client.
*/
static void SendPacket(const char packet) {
std::size_t sent_size = send(gdbserver_socket, &packet, 1, 0);
if (sent_size != 1) {
LOG_ERROR(Debug_GDBStub, "send failed");
}
}
/**
* Send reply to gdb client.
*
* @param reply Reply to be sent to client.
*/
static void SendReply(const char* reply) {
if (!IsConnected()) {
return;
}
memset(command_buffer, 0, sizeof(command_buffer));
command_length = static_cast<u32>(strlen(reply));
if (command_length + 4 > sizeof(command_buffer)) {
LOG_ERROR(Debug_GDBStub, "command_buffer overflow in SendReply");
return;
}
memcpy(command_buffer + 1, reply, command_length);
u8 checksum = CalculateChecksum(command_buffer, command_length + 1);
command_buffer[0] = GDB_STUB_START;
command_buffer[command_length + 1] = GDB_STUB_END;
command_buffer[command_length + 2] = NibbleToHex(checksum >> 4);
command_buffer[command_length + 3] = NibbleToHex(checksum);
u8* ptr = command_buffer;
u32 left = command_length + 4;
while (left > 0) {
int sent_size = send(gdbserver_socket, reinterpret_cast<char*>(ptr), left, 0);
if (sent_size < 0) {
LOG_ERROR(Debug_GDBStub, "gdb: send failed");
return Shutdown();
}
left -= sent_size;
ptr += sent_size;
}
}
/// Handle query command from gdb client.
static void HandleQuery() {
const char* query = reinterpret_cast<const char*>(command_buffer + 1);
LOG_DEBUG(Debug_GDBStub, "gdb: query '{}'\n", query);
if (strcmp(query, "TStatus") == 0) {
SendReply("T0");
} else if (strncmp(query, "Supported", strlen("Supported")) == 0) {
// PacketSize needs to be large enough for target xml
SendReply("PacketSize=2000;qXfer:features:read+;qXfer:threads:read+");
} else if (strncmp(query, "Xfer:features:read:target.xml:",
strlen("Xfer:features:read:target.xml:")) == 0) {
SendReply(target_xml);
} else if (strncmp(query, "fThreadInfo", strlen("fThreadInfo")) == 0) {
std::string val = "m";
u32 num_cores = Core::GetNumCores();
for (u32 i = 0; i < num_cores; ++i) {
const auto& threads =
Core::System::GetInstance().Kernel().GetThreadManager(i).GetThreadList();
for (const auto& thread : threads) {
val += fmt::format("{:x},", thread->GetThreadId());
}
}
val.pop_back();
SendReply(val.c_str());
} else if (strncmp(query, "sThreadInfo", strlen("sThreadInfo")) == 0) {
SendReply("l");
} else if (strncmp(query, "Xfer:threads:read", strlen("Xfer:threads:read")) == 0) {
std::string buffer;
buffer += "l<?xml version=\"1.0\"?>";
buffer += "<threads>";
u32 num_cores = Core::GetNumCores();
for (u32 i = 0; i < num_cores; ++i) {
const auto& threads =
Core::System::GetInstance().Kernel().GetThreadManager(i).GetThreadList();
for (const auto& thread : threads) {
buffer += fmt::format(R"*(<thread id="{:x}" name="Thread {:x}"></thread>)*",
thread->GetThreadId(), thread->GetThreadId());
}
}
buffer += "</threads>";
SendReply(buffer.c_str());
} else {
SendReply("");
}
}
/// Handle set thread command from gdb client.
static void HandleSetThread() {
int thread_id = -1;
if (command_buffer[2] != '-') {
thread_id = static_cast<int>(HexToInt(command_buffer + 2, command_length - 2));
}
if (thread_id >= 1) {
current_thread = FindThreadById(thread_id);
}
if (!current_thread) {
thread_id = 1;
current_thread = FindThreadById(thread_id);
}
if (current_thread) {
SendReply("OK");
return;
}
SendReply("E01");
}
/// Handle thread alive command from gdb client.
static void HandleThreadAlive() {
int thread_id = static_cast<int>(HexToInt(command_buffer + 1, command_length - 1));
if (thread_id == 0) {
thread_id = 1;
}
if (FindThreadById(thread_id)) {
SendReply("OK");
return;
}
SendReply("E01");
}
/**
* Send signal packet to client.
*
* @param signal Signal to be sent to client.
*/
static void SendSignal(Kernel::Thread* thread, u32 signal, bool full = true) {
if (gdbserver_socket == -1) {
return;
}
latest_signal = signal;
if (!thread) {
full = false;
}
std::string buffer;
if (full) {
buffer = fmt::format("T{:02x}{:02x}:{:08x};{:02x}:{:08x};{:02x}:{:08x}", latest_signal,
PC_REGISTER, htonl(Core::GetRunningCore().GetPC()), SP_REGISTER,
htonl(Core::GetRunningCore().GetReg(SP_REGISTER)), LR_REGISTER,
htonl(Core::GetRunningCore().GetReg(LR_REGISTER)));
} else {
buffer = fmt::format("T{:02x}", latest_signal);
}
if (thread) {
buffer += fmt::format(";thread:{:x};", thread->GetThreadId());
}
LOG_DEBUG(Debug_GDBStub, "Response: {}", buffer);
SendReply(buffer.c_str());
}
/// Read command from gdb client.
static void ReadCommand() {
command_length = 0;
memset(command_buffer, 0, sizeof(command_buffer));
u8 c = ReadByte();
if (c == '+') {
// ignore ack
return;
} else if (c == 0x03) {
LOG_INFO(Debug_GDBStub, "gdb: found break command\n");
halt_loop = true;
SendSignal(current_thread, SIGTRAP);
return;
} else if (c != GDB_STUB_START) {
LOG_DEBUG(Debug_GDBStub, "gdb: read invalid byte {:02x}\n", c);
return;
}
while ((c = ReadByte()) != GDB_STUB_END) {
if (command_length >= sizeof(command_buffer)) {
LOG_ERROR(Debug_GDBStub, "gdb: command_buffer overflow\n");
SendPacket(GDB_STUB_NACK);
return;
}
command_buffer[command_length++] = c;
}
u8 checksum_received = HexCharToValue(ReadByte()) << 4;
checksum_received |= HexCharToValue(ReadByte());
u8 checksum_calculated = CalculateChecksum(command_buffer, command_length);
if (checksum_received != checksum_calculated) {
LOG_ERROR(
Debug_GDBStub,
"gdb: invalid checksum: calculated {:02x} and read {:02x} for ${}# (length: {})\n",
checksum_calculated, checksum_received, reinterpret_cast<const char*>(command_buffer),
command_length);
command_length = 0;
SendPacket(GDB_STUB_NACK);
return;
}
SendPacket(GDB_STUB_ACK);
}
/// Check if there is data to be read from the gdb client.
static bool IsDataAvailable() {
if (!IsConnected()) {
return false;
}
fd_set fd_socket;
FD_ZERO(&fd_socket);
FD_SET(gdbserver_socket, &fd_socket);
struct timeval t;
t.tv_sec = 0;
t.tv_usec = 0;
if (select(gdbserver_socket + 1, &fd_socket, nullptr, nullptr, &t) < 0) {
LOG_ERROR(Debug_GDBStub, "select failed");
return false;
}
return FD_ISSET(gdbserver_socket, &fd_socket) != 0;
}
/// Send requested register to gdb client.
static void ReadRegister() {
static u8 reply[64];
memset(reply, 0, sizeof(reply));
u32 id = HexCharToValue(command_buffer[1]);
if (command_buffer[2] != '\0') {
id <<= 4;
id |= HexCharToValue(command_buffer[2]);
}
if (id <= PC_REGISTER) {
IntToGdbHex(reply, RegRead(id, current_thread));
} else if (id == CPSR_REGISTER) {
IntToGdbHex(reply, RegRead(id, current_thread));
} else if (id >= D0_REGISTER && id < FPSCR_REGISTER) {
LongToGdbHex(reply, FpuRead(id, current_thread));
} else if (id == FPSCR_REGISTER) {
IntToGdbHex(reply, static_cast<u32>(FpuRead(id, current_thread)));
} else {
return SendReply("E01");
}
SendReply(reinterpret_cast<char*>(reply));
}
/// Send all registers to the gdb client.
static void ReadRegisters() {
static u8 buffer[GDB_BUFFER_SIZE - 4];
memset(buffer, 0, sizeof(buffer));
u8* bufptr = buffer;
for (u32 reg = 0; reg <= PC_REGISTER; reg++) {
IntToGdbHex(bufptr + reg * 8, RegRead(reg, current_thread));
}
bufptr += 16 * 8;
IntToGdbHex(bufptr, RegRead(CPSR_REGISTER, current_thread));
bufptr += 8;
for (u32 reg = D0_REGISTER; reg < FPSCR_REGISTER; reg++) {
LongToGdbHex(bufptr + reg * 16, FpuRead(reg, current_thread));
}
bufptr += 16 * 16;
IntToGdbHex(bufptr, static_cast<u32>(FpuRead(FPSCR_REGISTER, current_thread)));
SendReply(reinterpret_cast<char*>(buffer));
}
/// Modify data of register specified by gdb client.
static void WriteRegister() {
const u8* buffer_ptr = command_buffer + 3;
u32 id = HexCharToValue(command_buffer[1]);
if (command_buffer[2] != '=') {
++buffer_ptr;
id <<= 4;
id |= HexCharToValue(command_buffer[2]);
}
if (id <= PC_REGISTER) {
RegWrite(id, GdbHexToInt(buffer_ptr), current_thread);
} else if (id == CPSR_REGISTER) {
RegWrite(id, GdbHexToInt(buffer_ptr), current_thread);
} else if (id >= D0_REGISTER && id < FPSCR_REGISTER) {
FpuWrite(id, GdbHexToLong(buffer_ptr), current_thread);
} else if (id == FPSCR_REGISTER) {
FpuWrite(id, GdbHexToInt(buffer_ptr), current_thread);
} else {
return SendReply("E01");
}
Core::GetRunningCore().LoadContext(current_thread->context);
SendReply("OK");
}
/// Modify all registers with data received from the client.
static void WriteRegisters() {
const u8* buffer_ptr = command_buffer + 1;
if (command_buffer[0] != 'G')
return SendReply("E01");
for (u32 i = 0, reg = 0; reg <= FPSCR_REGISTER; i++, reg++) {
if (reg <= PC_REGISTER) {
RegWrite(reg, GdbHexToInt(buffer_ptr + i * 8));
} else if (reg == CPSR_REGISTER) {
RegWrite(reg, GdbHexToInt(buffer_ptr + i * 8));
} else if (reg == CPSR_REGISTER - 1) {
// Dummy FPA register, ignore
} else if (reg < CPSR_REGISTER) {
// Dummy FPA registers, ignore
i += 2;
} else if (reg >= D0_REGISTER && reg < FPSCR_REGISTER) {
FpuWrite(reg, GdbHexToLong(buffer_ptr + i * 16));
i++; // Skip padding
} else if (reg == FPSCR_REGISTER) {
FpuWrite(reg, GdbHexToInt(buffer_ptr + i * 8));
}
}
Core::GetRunningCore().LoadContext(current_thread->context);
SendReply("OK");
}
/// Read location in memory specified by gdb client.
static void ReadMemory() {
static u8 reply[GDB_BUFFER_SIZE - 4];
auto start_offset = command_buffer + 1;
auto addr_pos = std::find(start_offset, command_buffer + command_length, ',');
VAddr addr = HexToInt(start_offset, static_cast<u32>(addr_pos - start_offset));
start_offset = addr_pos + 1;
u32 len =
HexToInt(start_offset, static_cast<u32>((command_buffer + command_length) - start_offset));
LOG_DEBUG(Debug_GDBStub, "gdb: addr: {:08x} len: {:08x}\n", addr, len);
if (len * 2 > sizeof(reply)) {
SendReply("E01");
}
if (!Memory::IsValidVirtualAddress(*Core::System::GetInstance().Kernel().GetCurrentProcess(),
addr)) {
return SendReply("E00");
}
std::vector<u8> data(len);
Core::System::GetInstance().Memory().ReadBlock(
*Core::System::GetInstance().Kernel().GetCurrentProcess(), addr, data.data(), len);
MemToGdbHex(reply, data.data(), len);
reply[len * 2] = '\0';
SendReply(reinterpret_cast<char*>(reply));
}
/// Modify location in memory with data received from the gdb client.
static void WriteMemory() {
auto start_offset = command_buffer + 1;
auto addr_pos = std::find(start_offset, command_buffer + command_length, ',');
VAddr addr = HexToInt(start_offset, static_cast<u32>(addr_pos - start_offset));
start_offset = addr_pos + 1;
auto len_pos = std::find(start_offset, command_buffer + command_length, ':');
u32 len = HexToInt(start_offset, static_cast<u32>(len_pos - start_offset));
if (!Memory::IsValidVirtualAddress(*Core::System::GetInstance().Kernel().GetCurrentProcess(),
addr)) {
return SendReply("E00");
}
std::vector<u8> data(len);
GdbHexToMem(data.data(), len_pos + 1, len);
Core::System::GetInstance().Memory().WriteBlock(
*Core::System::GetInstance().Kernel().GetCurrentProcess(), addr, data.data(), len);
Core::GetRunningCore().ClearInstructionCache();
SendReply("OK");
}
void Break(bool is_memory_break) {
send_trap = true;
memory_break = is_memory_break;
}
/// Tell the CPU that it should perform a single step.
static void Step() {
if (command_length > 1) {
RegWrite(PC_REGISTER, GdbHexToInt(command_buffer + 1), current_thread);
Core::GetRunningCore().LoadContext(current_thread->context);
}
step_loop = true;
halt_loop = true;
send_trap = true;
Core::GetRunningCore().ClearInstructionCache();
}
bool IsMemoryBreak() {
if (!IsConnected()) {
return false;
}
return memory_break;
}
/// Tell the CPU to continue executing.
static void Continue() {
memory_break = false;
step_loop = false;
halt_loop = false;
Core::GetRunningCore().ClearInstructionCache();
}
/**
* Commit breakpoint to list of breakpoints.
*
* @param type Type of breakpoint.
* @param addr Address of breakpoint.
* @param len Length of breakpoint.
*/
static bool CommitBreakpoint(BreakpointType type, VAddr addr, u32 len) {
BreakpointMap& p = GetBreakpointMap(type);
Breakpoint breakpoint;
breakpoint.active = true;
breakpoint.addr = addr;
breakpoint.len = len;
Core::System::GetInstance().Memory().ReadBlock(
*Core::System::GetInstance().Kernel().GetCurrentProcess(), addr, breakpoint.inst.data(),
breakpoint.inst.size());
static constexpr std::array<u8, 4> btrap{0x70, 0x00, 0x20, 0xe1};
if (type == BreakpointType::Execute) {
Core::System::GetInstance().Memory().WriteBlock(
*Core::System::GetInstance().Kernel().GetCurrentProcess(), addr, btrap.data(),
btrap.size());
Core::GetRunningCore().ClearInstructionCache();
}
p.insert({addr, breakpoint});
LOG_DEBUG(Debug_GDBStub, "gdb: added {} breakpoint: {:08x} bytes at {:08x}\n", type,
breakpoint.len, breakpoint.addr);
return true;
}
/// Handle add breakpoint command from gdb client.
static void AddBreakpoint() {
BreakpointType type;
u8 type_id = HexCharToValue(command_buffer[1]);
switch (type_id) {
case 0:
case 1:
type = BreakpointType::Execute;
break;
case 2:
type = BreakpointType::Write;
break;
case 3:
type = BreakpointType::Read;
break;
case 4:
type = BreakpointType::Access;
break;
default:
return SendReply("E01");
}
auto start_offset = command_buffer + 3;
auto addr_pos = std::find(start_offset, command_buffer + command_length, ',');
VAddr addr = HexToInt(start_offset, static_cast<u32>(addr_pos - start_offset));
start_offset = addr_pos + 1;
u32 len =
HexToInt(start_offset, static_cast<u32>((command_buffer + command_length) - start_offset));
if (type == BreakpointType::Access) {
// Access is made up of Read and Write types, so add both breakpoints
type = BreakpointType::Read;
if (!CommitBreakpoint(type, addr, len)) {
return SendReply("E02");
}
type = BreakpointType::Write;
}
if (!CommitBreakpoint(type, addr, len)) {
return SendReply("E02");
}
SendReply("OK");
}
/// Handle remove breakpoint command from gdb client.
static void RemoveBreakpoint() {
BreakpointType type;
u8 type_id = HexCharToValue(command_buffer[1]);
switch (type_id) {
case 0:
case 1:
type = BreakpointType::Execute;
break;
case 2:
type = BreakpointType::Write;
break;
case 3:
type = BreakpointType::Read;
break;
case 4:
type = BreakpointType::Access;
break;
default:
return SendReply("E01");
}
auto start_offset = command_buffer + 3;
auto addr_pos = std::find(start_offset, command_buffer + command_length, ',');
VAddr addr = HexToInt(start_offset, static_cast<u32>(addr_pos - start_offset));
if (type == BreakpointType::Access) {
// Access is made up of Read and Write types, so add both breakpoints
type = BreakpointType::Read;
RemoveBreakpoint(type, addr);
type = BreakpointType::Write;
}
RemoveBreakpoint(type, addr);
SendReply("OK");
}
void HandlePacket() {
if (!IsConnected()) {
if (defer_start) {
ToggleServer(true);
}
return;
}
if (!IsDataAvailable()) {
return;
}
ReadCommand();
if (command_length == 0) {
return;
}
LOG_DEBUG(Debug_GDBStub, "Packet: {}", command_buffer[0]);
switch (command_buffer[0]) {
case 'q':
HandleQuery();
break;
case 'H':
HandleSetThread();
break;
case '?':
SendSignal(current_thread, latest_signal);
break;
case 'k':
Shutdown();
LOG_INFO(Debug_GDBStub, "killed by gdb");
return;
case 'g':
ReadRegisters();
break;
case 'G':
WriteRegisters();
break;
case 'p':
ReadRegister();
break;
case 'P':
WriteRegister();
break;
case 'm':
ReadMemory();
break;
case 'M':
WriteMemory();
break;
case 's':
Step();
return;
case 'C':
case 'c':
Continue();
return;
case 'z':
RemoveBreakpoint();
break;
case 'Z':
AddBreakpoint();
break;
case 'T':
HandleThreadAlive();
break;
default:
SendReply("");
break;
}
}
void SetServerPort(u16 port) {
gdbstub_port = port;
}
void ToggleServer(bool status) {
if (status) {
server_enabled = status;
// Start server
if (!IsConnected() && Core::System::GetInstance().IsPoweredOn()) {
Init();
}
} else {
// Stop server
if (IsConnected()) {
Shutdown();
}
server_enabled = status;
}
}
void DeferStart() {
defer_start = true;
}
static void Init(u16 port) {
if (!server_enabled) {
// Set the halt loop to false in case the user enabled the gdbstub mid-execution.
// This way the CPU can still execute normally.
halt_loop = false;
step_loop = false;
return;
}
// Setup initial gdbstub status
halt_loop = true;
step_loop = false;
breakpoints_execute.clear();
breakpoints_read.clear();
breakpoints_write.clear();
// Start gdb server
LOG_INFO(Debug_GDBStub, "Starting GDB server on port {}...", port);
sockaddr_in saddr_server = {};
saddr_server.sin_family = AF_INET;
saddr_server.sin_port = htons(port);
saddr_server.sin_addr.s_addr = INADDR_ANY;
#ifdef _WIN32
WSAStartup(MAKEWORD(2, 2), &InitData);
#endif
int tmpsock = static_cast<int>(socket(PF_INET, SOCK_STREAM, 0));
if (tmpsock == -1) {
LOG_ERROR(Debug_GDBStub, "Failed to create gdb socket");
}
// Set socket to SO_REUSEADDR so it can always bind on the same port
int reuse_enabled = 1;
if (setsockopt(tmpsock, SOL_SOCKET, SO_REUSEADDR, (const char*)&reuse_enabled,
sizeof(reuse_enabled)) < 0) {
LOG_ERROR(Debug_GDBStub, "Failed to set gdb socket option");
}
const sockaddr* server_addr = reinterpret_cast<const sockaddr*>(&saddr_server);
socklen_t server_addrlen = sizeof(saddr_server);
if (bind(tmpsock, server_addr, server_addrlen) < 0) {
LOG_ERROR(Debug_GDBStub, "Failed to bind gdb socket");
}
if (listen(tmpsock, 1) < 0) {
LOG_ERROR(Debug_GDBStub, "Failed to listen to gdb socket");
}
// Wait for gdb to connect
LOG_INFO(Debug_GDBStub, "Waiting for gdb to connect...\n");
sockaddr_in saddr_client;
sockaddr* client_addr = reinterpret_cast<sockaddr*>(&saddr_client);
socklen_t client_addrlen = sizeof(saddr_client);
gdbserver_socket = static_cast<int>(accept(tmpsock, client_addr, &client_addrlen));
if (gdbserver_socket < 0) {
// In the case that we couldn't start the server for whatever reason, just start CPU
// execution like normal.
halt_loop = false;
step_loop = false;
LOG_ERROR(Debug_GDBStub, "Failed to accept gdb client");
} else {
LOG_INFO(Debug_GDBStub, "Client connected.\n");
saddr_client.sin_addr.s_addr = ntohl(saddr_client.sin_addr.s_addr);
}
// Clean up temporary socket if it's still alive at this point.
if (tmpsock != -1) {
shutdown(tmpsock, SHUT_RDWR);
}
}
void Init() {
Init(gdbstub_port);
}
void Shutdown() {
if (!server_enabled) {
return;
}
defer_start = false;
LOG_INFO(Debug_GDBStub, "Stopping GDB ...");
if (gdbserver_socket != -1) {
shutdown(gdbserver_socket, SHUT_RDWR);
gdbserver_socket = -1;
}
#ifdef _WIN32
WSACleanup();
#endif
LOG_INFO(Debug_GDBStub, "GDB stopped.");
}
bool IsServerEnabled() {
return server_enabled;
}
bool IsConnected() {
return IsServerEnabled() && gdbserver_socket != -1;
}
bool GetCpuHaltFlag() {
return halt_loop;
}
bool GetCpuStepFlag() {
return step_loop;
}
void SetCpuStepFlag(bool is_step) {
step_loop = is_step;
}
void SendTrap(Kernel::Thread* thread, int trap) {
if (!send_trap) {
return;
}
current_thread = thread;
SendSignal(thread, trap);
halt_loop = true;
send_trap = false;
}
}; // namespace GDBStub
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