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Diffstat (limited to 'src/core/debugger/gdbstub.cpp')
| -rw-r--r-- | src/core/debugger/gdbstub.cpp | 382 |
1 files changed, 382 insertions, 0 deletions
diff --git a/src/core/debugger/gdbstub.cpp b/src/core/debugger/gdbstub.cpp new file mode 100644 index 000000000..718c45952 --- /dev/null +++ b/src/core/debugger/gdbstub.cpp @@ -0,0 +1,382 @@ +// SPDX-FileCopyrightText: Copyright 2022 yuzu Emulator Project +// SPDX-License-Identifier: GPL-2.0-or-later + +#include <atomic> +#include <numeric> +#include <optional> +#include <thread> + +#include <boost/asio.hpp> +#include <boost/process/async_pipe.hpp> + +#include "common/hex_util.h" +#include "common/logging/log.h" +#include "common/scope_exit.h" +#include "core/arm/arm_interface.h" +#include "core/core.h" +#include "core/debugger/gdbstub.h" +#include "core/debugger/gdbstub_arch.h" +#include "core/hle/kernel/k_page_table.h" +#include "core/hle/kernel/k_process.h" +#include "core/hle/kernel/k_thread.h" +#include "core/loader/loader.h" +#include "core/memory.h" + +namespace Core { + +constexpr char GDB_STUB_START = '$'; +constexpr char GDB_STUB_END = '#'; +constexpr char GDB_STUB_ACK = '+'; +constexpr char GDB_STUB_NACK = '-'; +constexpr char GDB_STUB_INT3 = 0x03; +constexpr int GDB_STUB_SIGTRAP = 5; + +constexpr char GDB_STUB_REPLY_ERR[] = "E01"; +constexpr char GDB_STUB_REPLY_OK[] = "OK"; +constexpr char GDB_STUB_REPLY_EMPTY[] = ""; + +GDBStub::GDBStub(DebuggerBackend& backend_, Core::System& system_) + : DebuggerFrontend(backend_), system{system_} { + if (system.CurrentProcess()->Is64BitProcess()) { + arch = std::make_unique<GDBStubA64>(); + } else { + arch = std::make_unique<GDBStubA32>(); + } +} + +GDBStub::~GDBStub() = default; + +void GDBStub::Connected() {} + +void GDBStub::Stopped(Kernel::KThread* thread) { + SendReply(arch->ThreadStatus(thread, GDB_STUB_SIGTRAP)); +} + +std::vector<DebuggerAction> GDBStub::ClientData(std::span<const u8> data) { + std::vector<DebuggerAction> actions; + current_command.insert(current_command.end(), data.begin(), data.end()); + + while (current_command.size() != 0) { + ProcessData(actions); + } + + return actions; +} + +void GDBStub::ProcessData(std::vector<DebuggerAction>& actions) { + const char c{current_command[0]}; + + // Acknowledgement + if (c == GDB_STUB_ACK || c == GDB_STUB_NACK) { + current_command.erase(current_command.begin()); + return; + } + + // Interrupt + if (c == GDB_STUB_INT3) { + LOG_INFO(Debug_GDBStub, "Received interrupt"); + current_command.erase(current_command.begin()); + actions.push_back(DebuggerAction::Interrupt); + SendStatus(GDB_STUB_ACK); + return; + } + + // Otherwise, require the data to be the start of a command + if (c != GDB_STUB_START) { + LOG_ERROR(Debug_GDBStub, "Invalid command buffer contents: {}", current_command.data()); + current_command.clear(); + SendStatus(GDB_STUB_NACK); + return; + } + + // Continue reading until command is complete + while (CommandEnd() == current_command.end()) { + const auto new_data{backend.ReadFromClient()}; + current_command.insert(current_command.end(), new_data.begin(), new_data.end()); + } + + // Execute and respond to GDB + const auto command{DetachCommand()}; + + if (command) { + SendStatus(GDB_STUB_ACK); + ExecuteCommand(*command, actions); + } else { + SendStatus(GDB_STUB_NACK); + } +} + +void GDBStub::ExecuteCommand(std::string_view packet, std::vector<DebuggerAction>& actions) { + LOG_TRACE(Debug_GDBStub, "Executing command: {}", packet); + + if (packet.length() == 0) { + SendReply(GDB_STUB_REPLY_ERR); + return; + } + + std::string_view command{packet.substr(1, packet.size())}; + + switch (packet[0]) { + case 'H': { + Kernel::KThread* thread{nullptr}; + s64 thread_id{strtoll(command.data() + 1, nullptr, 16)}; + if (thread_id >= 1) { + thread = GetThreadByID(thread_id); + } + + if (thread) { + SendReply(GDB_STUB_REPLY_OK); + backend.SetActiveThread(thread); + } else { + SendReply(GDB_STUB_REPLY_ERR); + } + break; + } + case 'T': { + s64 thread_id{strtoll(command.data(), nullptr, 16)}; + if (GetThreadByID(thread_id)) { + SendReply(GDB_STUB_REPLY_OK); + } else { + SendReply(GDB_STUB_REPLY_ERR); + } + break; + } + case 'q': + HandleQuery(command); + break; + case '?': + SendReply(arch->ThreadStatus(backend.GetActiveThread(), GDB_STUB_SIGTRAP)); + break; + case 'k': + LOG_INFO(Debug_GDBStub, "Shutting down emulation"); + actions.push_back(DebuggerAction::ShutdownEmulation); + break; + case 'g': + SendReply(arch->ReadRegisters(backend.GetActiveThread())); + break; + case 'G': + arch->WriteRegisters(backend.GetActiveThread(), command); + SendReply(GDB_STUB_REPLY_OK); + break; + case 'p': { + const size_t reg{static_cast<size_t>(strtoll(command.data(), nullptr, 16))}; + SendReply(arch->RegRead(backend.GetActiveThread(), reg)); + break; + } + case 'P': { + const auto sep{std::find(command.begin(), command.end(), '=') - command.begin() + 1}; + const size_t reg{static_cast<size_t>(strtoll(command.data(), nullptr, 16))}; + arch->RegWrite(backend.GetActiveThread(), reg, std::string_view(command).substr(sep)); + break; + } + case 'm': { + const auto sep{std::find(command.begin(), command.end(), ',') - command.begin() + 1}; + const size_t addr{static_cast<size_t>(strtoll(command.data(), nullptr, 16))}; + const size_t size{static_cast<size_t>(strtoll(command.data() + sep, nullptr, 16))}; + + if (system.Memory().IsValidVirtualAddressRange(addr, size)) { + std::vector<u8> mem(size); + system.Memory().ReadBlock(addr, mem.data(), size); + + SendReply(Common::HexToString(mem)); + } else { + SendReply(GDB_STUB_REPLY_ERR); + } + break; + } + case 'M': { + const auto size_sep{std::find(command.begin(), command.end(), ',') - command.begin() + 1}; + const auto mem_sep{std::find(command.begin(), command.end(), ':') - command.begin() + 1}; + + const size_t addr{static_cast<size_t>(strtoll(command.data(), nullptr, 16))}; + const size_t size{static_cast<size_t>(strtoll(command.data() + size_sep, nullptr, 16))}; + + const auto mem_substr{std::string_view(command).substr(mem_sep)}; + const auto mem{Common::HexStringToVector(mem_substr, false)}; + + if (system.Memory().IsValidVirtualAddressRange(addr, size)) { + system.Memory().WriteBlock(addr, mem.data(), size); + system.InvalidateCpuInstructionCacheRange(addr, size); + SendReply(GDB_STUB_REPLY_OK); + } else { + SendReply(GDB_STUB_REPLY_ERR); + } + break; + } + case 's': + actions.push_back(DebuggerAction::StepThread); + break; + case 'C': + case 'c': + actions.push_back(DebuggerAction::Continue); + break; + case 'Z': { + const auto addr_sep{std::find(command.begin(), command.end(), ',') - command.begin() + 1}; + const size_t addr{static_cast<size_t>(strtoll(command.data() + addr_sep, nullptr, 16))}; + + if (system.Memory().IsValidVirtualAddress(addr)) { + replaced_instructions[addr] = system.Memory().Read32(addr); + system.Memory().Write32(addr, arch->BreakpointInstruction()); + system.InvalidateCpuInstructionCacheRange(addr, sizeof(u32)); + + SendReply(GDB_STUB_REPLY_OK); + } else { + SendReply(GDB_STUB_REPLY_ERR); + } + break; + } + case 'z': { + const auto addr_sep{std::find(command.begin(), command.end(), ',') - command.begin() + 1}; + const size_t addr{static_cast<size_t>(strtoll(command.data() + addr_sep, nullptr, 16))}; + + const auto orig_insn{replaced_instructions.find(addr)}; + if (system.Memory().IsValidVirtualAddress(addr) && + orig_insn != replaced_instructions.end()) { + system.Memory().Write32(addr, orig_insn->second); + system.InvalidateCpuInstructionCacheRange(addr, sizeof(u32)); + replaced_instructions.erase(addr); + + SendReply(GDB_STUB_REPLY_OK); + } else { + SendReply(GDB_STUB_REPLY_ERR); + } + break; + } + default: + SendReply(GDB_STUB_REPLY_EMPTY); + break; + } +} + +void GDBStub::HandleQuery(std::string_view command) { + if (command.starts_with("TStatus")) { + // no tracepoint support + SendReply("T0"); + } else if (command.starts_with("Supported")) { + SendReply("PacketSize=4000;qXfer:features:read+;qXfer:threads:read+;qXfer:libraries:read+"); + } else if (command.starts_with("Xfer:features:read:target.xml:")) { + const auto offset{command.substr(30)}; + const auto amount{command.substr(command.find(',') + 1)}; + + const auto offset_val{static_cast<u64>(strtoll(offset.data(), nullptr, 16))}; + const auto amount_val{static_cast<u64>(strtoll(amount.data(), nullptr, 16))}; + const auto target_xml{arch->GetTargetXML()}; + + if (offset_val + amount_val > target_xml.size()) { + SendReply("l" + target_xml.substr(offset_val)); + } else { + SendReply("m" + target_xml.substr(offset_val, amount_val)); + } + } else if (command.starts_with("Offsets")) { + Loader::AppLoader::Modules modules; + system.GetAppLoader().ReadNSOModules(modules); + + const auto main = std::find_if(modules.begin(), modules.end(), + [](const auto& key) { return key.second == "main"; }); + if (main != modules.end()) { + SendReply(fmt::format("TextSeg={:x}", main->first)); + } else { + SendReply(fmt::format("TextSeg={:x}", + system.CurrentProcess()->PageTable().GetCodeRegionStart())); + } + } else if (command.starts_with("fThreadInfo")) { + // beginning of list + const auto& threads = system.GlobalSchedulerContext().GetThreadList(); + std::vector<std::string> thread_ids; + for (const auto& thread : threads) { + thread_ids.push_back(fmt::format("{:x}", thread->GetThreadID())); + } + SendReply(fmt::format("m{}", fmt::join(thread_ids, ","))); + } else if (command.starts_with("sThreadInfo")) { + // end of list + SendReply("l"); + } else if (command.starts_with("Xfer:threads:read")) { + std::string buffer; + buffer += R"(l<?xml version="1.0"?>)"; + buffer += "<threads>"; + + const auto& threads = system.GlobalSchedulerContext().GetThreadList(); + for (const auto& thread : threads) { + buffer += + fmt::format(R"(<thread id="{:x}" core="{:d}" name="Thread {:d}"/>)", + thread->GetThreadID(), thread->GetActiveCore(), thread->GetThreadID()); + } + + buffer += "</threads>"; + SendReply(buffer); + } else { + SendReply(GDB_STUB_REPLY_EMPTY); + } +} + +Kernel::KThread* GDBStub::GetThreadByID(u64 thread_id) { + const auto& threads{system.GlobalSchedulerContext().GetThreadList()}; + for (auto* thread : threads) { + if (thread->GetThreadID() == thread_id) { + return thread; + } + } + + return nullptr; +} + +std::vector<char>::const_iterator GDBStub::CommandEnd() const { + // Find the end marker + const auto end{std::find(current_command.begin(), current_command.end(), GDB_STUB_END)}; + + // Require the checksum to be present + return std::min(end + 2, current_command.end()); +} + +std::optional<std::string> GDBStub::DetachCommand() { + // Slice the string part from the beginning to the end marker + const auto end{CommandEnd()}; + + // Extract possible command data + std::string data(current_command.data(), end - current_command.begin() + 1); + + // Shift over the remaining contents + current_command.erase(current_command.begin(), end + 1); + + // Validate received command + if (data[0] != GDB_STUB_START) { + LOG_ERROR(Debug_GDBStub, "Invalid start data: {}", data[0]); + return std::nullopt; + } + + u8 calculated = CalculateChecksum(std::string_view(data).substr(1, data.size() - 4)); + u8 received = static_cast<u8>(strtoll(data.data() + data.size() - 2, nullptr, 16)); + + // Verify checksum + if (calculated != received) { + LOG_ERROR(Debug_GDBStub, "Checksum mismatch: calculated {:02x}, received {:02x}", + calculated, received); + return std::nullopt; + } + + return data.substr(1, data.size() - 4); +} + +u8 GDBStub::CalculateChecksum(std::string_view data) { + return static_cast<u8>( + std::accumulate(data.begin(), data.end(), u8{0}, [](u8 lhs, u8 rhs) { return lhs + rhs; })); +} + +void GDBStub::SendReply(std::string_view data) { + const auto output{ + fmt::format("{}{}{}{:02x}", GDB_STUB_START, data, GDB_STUB_END, CalculateChecksum(data))}; + LOG_TRACE(Debug_GDBStub, "Writing reply: {}", output); + + // C++ string support is complete rubbish + const u8* output_begin = reinterpret_cast<const u8*>(output.data()); + const u8* output_end = output_begin + output.size(); + backend.WriteToClient(std::span<const u8>(output_begin, output_end)); +} + +void GDBStub::SendStatus(char status) { + std::array<u8, 1> buf = {static_cast<u8>(status)}; + LOG_TRACE(Debug_GDBStub, "Writing status: {}", status); + backend.WriteToClient(buf); +} + +} // namespace Core |