GDBStub: Support watchpoints on linux (#1030)

* GDBStub: Support watchpoints on linux
* GDBStub: Use `TCP_NODELAY`

src/Cafe/CMakeLists.txt

@@ -40,6 +40,7 @@ add_library(CemuCafe
   HW/Espresso/Debugger/DebugSymbolStorage.h
   HW/Espresso/Debugger/GDBStub.h
   HW/Espresso/Debugger/GDBStub.cpp
+  HW/Espresso/Debugger/GDBBreakpoints.cpp
   HW/Espresso/Debugger/GDBBreakpoints.h
   HW/Espresso/EspressoISA.h
   HW/Espresso/Interpreter/PPCInterpreterALU.hpp

src/Cafe/HW/Espresso/Debugger/GDBBreakpoints.cpp

@@ -0,0 +1,304 @@
+#include "GDBBreakpoints.h"
+#include "Debugger.h"
+#include "Cafe/HW/Espresso/Recompiler/PPCRecompiler.h"
+
+#if defined(ARCH_X86_64) && BOOST_OS_LINUX
+#include <sys/ptrace.h>
+#include <sys/wait.h>
+#include <sys/user.h>
+
+DRType _GetDR(pid_t tid, int drIndex)
+{
+	size_t drOffset = offsetof(struct user, u_debugreg) + drIndex * sizeof(user::u_debugreg[0]);
+
+	long v;
+	v = ptrace(PTRACE_PEEKUSER, tid, drOffset, nullptr);
+	if (v == -1)
+		perror("ptrace(PTRACE_PEEKUSER)");
+
+	return (DRType)v;
+}
+
+void _SetDR(pid_t tid, int drIndex, DRType newValue)
+{
+	size_t drOffset = offsetof(struct user, u_debugreg) + drIndex * sizeof(user::u_debugreg[0]);
+
+	long rc = ptrace(PTRACE_POKEUSER, tid, drOffset, newValue);
+	if (rc == -1)
+		perror("ptrace(PTRACE_POKEUSER)");
+}
+
+DRType _ReadDR6()
+{
+	pid_t tid = gettid();
+
+	// linux doesn't let us attach to the current thread / threads in the current thread group
+	// we have to create a child process which then modifies the debug registers and quits
+	pid_t child = fork();
+	if (child == -1)
+	{
+		perror("fork");
+		return 0;
+	}
+
+	if (child == 0)
+	{
+		if (ptrace(PTRACE_ATTACH, tid, nullptr, nullptr))
+		{
+			perror("attach");
+			_exit(0);
+		}
+
+		waitpid(tid, NULL, 0);
+
+		uint64_t dr6 = _GetDR(tid, 6);
+
+		if (ptrace(PTRACE_DETACH, tid, nullptr, nullptr))
+			perror("detach");
+
+		// since the status code only uses the lower 8 bits, we have to discard the rest of DR6
+		// this should be fine though, since the lower 4 bits of DR6 contain all the bp conditions
+		_exit(dr6 & 0xff);
+	}
+
+	// wait for child process
+	int wstatus;
+	waitpid(child, &wstatus, 0);
+
+	return (DRType)WEXITSTATUS(wstatus);
+}
+#endif
+
+GDBServer::ExecutionBreakpoint::ExecutionBreakpoint(MPTR address, BreakpointType type, bool visible, std::string reason)
+	: m_address(address), m_removedAfterInterrupt(false), m_reason(std::move(reason))
+{
+	if (type == BreakpointType::BP_SINGLE)
+	{
+		this->m_pauseThreads = true;
+		this->m_restoreAfterInterrupt = false;
+		this->m_deleteAfterAnyInterrupt = false;
+		this->m_pauseOnNextInterrupt = false;
+		this->m_visible = visible;
+	}
+	else if (type == BreakpointType::BP_PERSISTENT)
+	{
+		this->m_pauseThreads = true;
+		this->m_restoreAfterInterrupt = true;
+		this->m_deleteAfterAnyInterrupt = false;
+		this->m_pauseOnNextInterrupt = false;
+		this->m_visible = visible;
+	}
+	else if (type == BreakpointType::BP_RESTORE_POINT)
+	{
+		this->m_pauseThreads = false;
+		this->m_restoreAfterInterrupt = false;
+		this->m_deleteAfterAnyInterrupt = false;
+		this->m_pauseOnNextInterrupt = false;
+		this->m_visible = false;
+	}
+	else if (type == BreakpointType::BP_STEP_POINT)
+	{
+		this->m_pauseThreads = false;
+		this->m_restoreAfterInterrupt = false;
+		this->m_deleteAfterAnyInterrupt = true;
+		this->m_pauseOnNextInterrupt = true;
+		this->m_visible = false;
+	}
+
+	this->m_origOpCode = memory_readU32(address);
+	memory_writeU32(address, DEBUGGER_BP_T_GDBSTUB_TW);
+	PPCRecompiler_invalidateRange(address, address + 4);
+}
+
+GDBServer::ExecutionBreakpoint::~ExecutionBreakpoint()
+{
+	memory_writeU32(this->m_address, this->m_origOpCode);
+	PPCRecompiler_invalidateRange(this->m_address, this->m_address + 4);
+}
+
+uint32 GDBServer::ExecutionBreakpoint::GetVisibleOpCode() const
+{
+	if (this->m_visible)
+		return memory_readU32(this->m_address);
+	else
+		return this->m_origOpCode;
+}
+
+void GDBServer::ExecutionBreakpoint::RemoveTemporarily()
+{
+	memory_writeU32(this->m_address, this->m_origOpCode);
+	PPCRecompiler_invalidateRange(this->m_address, this->m_address + 4);
+	this->m_restoreAfterInterrupt = true;
+}
+
+void GDBServer::ExecutionBreakpoint::Restore()
+{
+	memory_writeU32(this->m_address, DEBUGGER_BP_T_GDBSTUB_TW);
+	PPCRecompiler_invalidateRange(this->m_address, this->m_address + 4);
+	this->m_restoreAfterInterrupt = false;
+}
+
+namespace coreinit
+{
+#if BOOST_OS_LINUX
+	std::vector<pid_t>& OSGetSchedulerThreadIds();
+#endif
+
+	std::vector<std::thread::native_handle_type>& OSGetSchedulerThreads();
+}
+
+GDBServer::AccessBreakpoint::AccessBreakpoint(MPTR address, AccessPointType type)
+	: m_address(address), m_type(type)
+{
+#if defined(ARCH_X86_64) && BOOST_OS_WINDOWS
+	for (auto& hThreadNH : coreinit::OSGetSchedulerThreads())
+	{
+		HANDLE hThread = (HANDLE)hThreadNH;
+		CONTEXT ctx{};
+		ctx.ContextFlags = CONTEXT_DEBUG_REGISTERS;
+		SuspendThread(hThread);
+		GetThreadContext(hThread, &ctx);
+
+		// use BP 2/3 for gdb stub since cemu's internal debugger uses BP 0/1 already
+		ctx.Dr2 = (DWORD64)memory_getPointerFromVirtualOffset(address);
+		ctx.Dr3 = (DWORD64)memory_getPointerFromVirtualOffset(address);
+		// breakpoint 2
+		SetBits(ctx.Dr7, 4, 1, 1);	// breakpoint #3 enabled: true
+		SetBits(ctx.Dr7, 24, 2, 1); // breakpoint #3 condition: 1 (write)
+		SetBits(ctx.Dr7, 26, 2, 3); // breakpoint #3 length: 3 (4 bytes)
+		// breakpoint 3
+		SetBits(ctx.Dr7, 6, 1, 1);	// breakpoint #4 enabled: true
+		SetBits(ctx.Dr7, 28, 2, 3); // breakpoint #4 condition: 3 (read & write)
+		SetBits(ctx.Dr7, 30, 2, 3); // breakpoint #4 length: 3 (4 bytes)
+
+		SetThreadContext(hThread, &ctx);
+		ResumeThread(hThread);
+	}
+#elif defined(ARCH_X86_64) && BOOST_OS_LINUX
+	// linux doesn't let us attach to threads which are in the same thread group as our current thread
+	// we have to create a child process which then modifies the debug registers and quits
+	pid_t child = fork();
+	if (child == -1)
+	{
+		perror("fork");
+		return;
+	}
+
+	if (child == 0)
+	{
+		for (pid_t tid : coreinit::OSGetSchedulerThreadIds())
+		{
+			long rc = ptrace(PTRACE_ATTACH, tid, nullptr, nullptr);
+			if (rc == -1)
+				perror("ptrace(PTRACE_ATTACH)");
+
+			waitpid(tid, nullptr, 0);
+
+			DRType dr7 = _GetDR(tid, 7);
+			// use BP 2/3 for gdb stub since cemu's internal debugger uses BP 0/1 already
+			DRType dr2 = (uint64)memory_getPointerFromVirtualOffset(address);
+			DRType dr3 = (uint64)memory_getPointerFromVirtualOffset(address);
+			// breakpoint 2
+			SetBits(dr7, 4, 1, 1);  // breakpoint #3 enabled: true
+			SetBits(dr7, 24, 2, 1); // breakpoint #3 condition: 1 (write)
+			SetBits(dr7, 26, 2, 3); // breakpoint #3 length: 3 (4 bytes)
+			// breakpoint 3
+			SetBits(dr7, 6, 1, 1);  // breakpoint #4 enabled: true
+			SetBits(dr7, 28, 2, 3); // breakpoint #4 condition: 3 (read & write)
+			SetBits(dr7, 30, 2, 3); // breakpoint #4 length: 3 (4 bytes)
+
+			_SetDR(tid, 2, dr2);
+			_SetDR(tid, 3, dr3);
+			_SetDR(tid, 7, dr7);
+
+			rc = ptrace(PTRACE_DETACH, tid, nullptr, nullptr);
+			if (rc == -1)
+				perror("ptrace(PTRACE_DETACH)");
+		}
+
+		// exit child process
+		_exit(0);
+	}
+
+	// wait for child process
+	waitpid(child, nullptr, 0);
+#else
+	cemuLog_log(LogType::Force, "Debugger read/write breakpoints are not supported on non-x86 CPUs yet.");
+#endif
+}
+
+GDBServer::AccessBreakpoint::~AccessBreakpoint()
+{
+#if defined(ARCH_X86_64) && BOOST_OS_WINDOWS
+	for (auto& hThreadNH : coreinit::OSGetSchedulerThreads())
+	{
+		HANDLE hThread = (HANDLE)hThreadNH;
+		CONTEXT ctx{};
+		ctx.ContextFlags = CONTEXT_DEBUG_REGISTERS;
+		SuspendThread(hThread);
+		GetThreadContext(hThread, &ctx);
+
+		// reset BP 2/3 to zero
+		ctx.Dr2 = (DWORD64)0;
+		ctx.Dr3 = (DWORD64)0;
+		// breakpoint 2
+		SetBits(ctx.Dr7, 4, 1, 0);
+		SetBits(ctx.Dr7, 24, 2, 0);
+		SetBits(ctx.Dr7, 26, 2, 0);
+		// breakpoint 3
+		SetBits(ctx.Dr7, 6, 1, 0);
+		SetBits(ctx.Dr7, 28, 2, 0);
+		SetBits(ctx.Dr7, 30, 2, 0);
+		SetThreadContext(hThread, &ctx);
+		ResumeThread(hThread);
+	}
+#elif defined(ARCH_X86_64) && BOOST_OS_LINUX
+	// linux doesn't let us attach to threads which are in the same thread group as our current thread
+	// we have to create a child process which then modifies the debug registers and quits
+	pid_t child = fork();
+	if (child == -1)
+	{
+		perror("fork");
+		return;
+	}
+
+	if (child == 0)
+	{
+		for (pid_t tid : coreinit::OSGetSchedulerThreadIds())
+		{
+			long rc = ptrace(PTRACE_ATTACH, tid, nullptr, nullptr);
+			if (rc == -1)
+				perror("ptrace(PTRACE_ATTACH)");
+
+			waitpid(tid, nullptr, 0);
+
+			DRType dr7 = _GetDR(tid, 7);
+			// reset BP 2/3 to zero
+			DRType dr2 = 0;
+			DRType dr3 = 0;
+			// breakpoint 2
+			SetBits(dr7, 4, 1, 0);
+			SetBits(dr7, 24, 2, 0);
+			SetBits(dr7, 26, 2, 0);
+			// breakpoint 3
+			SetBits(dr7, 6, 1, 0);
+			SetBits(dr7, 28, 2, 0);
+			SetBits(dr7, 30, 2, 0);
+
+			_SetDR(tid, 2, dr2);
+			_SetDR(tid, 3, dr3);
+			_SetDR(tid, 7, dr7);
+
+			rc = ptrace(PTRACE_DETACH, tid, nullptr, nullptr);
+			if (rc == -1)
+				perror("ptrace(PTRACE_DETACH)");
+		}
+
+		// exit child process
+		_exit(0);
+	}
+
+	// wait for child process
+	waitpid(child, nullptr, 0);
+#endif
+}

src/Cafe/HW/Espresso/Debugger/GDBBreakpoints.h

@@ -1,33 +1,18 @@
+#pragma once
+#include "GDBStub.h"
 #include <utility>
 
-#if defined(ARCH_X86_64) && BOOST_OS_LINUX && FALSE
+#if defined(ARCH_X86_64) && BOOST_OS_LINUX
-#include <sys/ptrace.h>
+#include <sys/types.h>
-#include <sys/wait.h>
-#include <sys/user.h>
 
 // helpers for accessing debug register
 typedef unsigned long DRType;
 
-DRType _GetDR(pid_t tid, int drIndex)
+DRType _GetDR(pid_t tid, int drIndex);
-{
+void _SetDR(pid_t tid, int drIndex, DRType newValue);
-	unsigned long v;
+DRType _ReadDR6();
-	v = ptrace (PTRACE_PEEKUSER, tid, offsetof (struct user, u_debugreg[drIndex]), 0);
-	return (DRType)v;
-}
-
-void _SetDR(pid_t tid, int drIndex, DRType newValue)
-{
-	unsigned long v = newValue;
-	ptrace (PTRACE_POKEUSER, tid, offsetof (struct user, u_debugreg[drIndex]), v);
-}
-
 #endif
 
-namespace coreinit
-{
-	std::vector<std::thread::native_handle_type>& OSGetSchedulerThreads();
-}
-
 enum class BreakpointType
 {
 	BP_SINGLE,
@@ -38,59 +23,10 @@ enum class BreakpointType
 
 class GDBServer::ExecutionBreakpoint {
 public:
-	ExecutionBreakpoint(MPTR address, BreakpointType type, bool visible, std::string reason)
+	ExecutionBreakpoint(MPTR address, BreakpointType type, bool visible, std::string reason);
-		: m_address(address), m_removedAfterInterrupt(false), m_reason(std::move(reason))
+	~ExecutionBreakpoint();
-	{
-		if (type == BreakpointType::BP_SINGLE)
-		{
-			this->m_pauseThreads = true;
-			this->m_restoreAfterInterrupt = false;
-			this->m_deleteAfterAnyInterrupt = false;
-			this->m_pauseOnNextInterrupt = false;
-			this->m_visible = visible;
-		}
-		else if (type == BreakpointType::BP_PERSISTENT)
-		{
-			this->m_pauseThreads = true;
-			this->m_restoreAfterInterrupt = true;
-			this->m_deleteAfterAnyInterrupt = false;
-			this->m_pauseOnNextInterrupt = false;
-			this->m_visible = visible;
-		}
-		else if (type == BreakpointType::BP_RESTORE_POINT)
-		{
-			this->m_pauseThreads = false;
-			this->m_restoreAfterInterrupt = false;
-			this->m_deleteAfterAnyInterrupt = false;
-			this->m_pauseOnNextInterrupt = false;
-			this->m_visible = false;
-		}
-		else if (type == BreakpointType::BP_STEP_POINT)
-		{
-			this->m_pauseThreads = false;
-			this->m_restoreAfterInterrupt = false;
-			this->m_deleteAfterAnyInterrupt = true;
-			this->m_pauseOnNextInterrupt = true;
-			this->m_visible = false;
-		}
 
-		this->m_origOpCode = memory_readU32(address);
+	[[nodiscard]] uint32 GetVisibleOpCode() const;
-		memory_writeU32(address, DEBUGGER_BP_T_GDBSTUB_TW);
-		PPCRecompiler_invalidateRange(address, address + 4);
-	};
-	~ExecutionBreakpoint()
-	{
-		memory_writeU32(this->m_address, this->m_origOpCode);
-		PPCRecompiler_invalidateRange(this->m_address, this->m_address + 4);
-	};
-
-	[[nodiscard]] uint32 GetVisibleOpCode() const
-	{
-		if (this->m_visible)
-			return memory_readU32(this->m_address);
-		else
-			return this->m_origOpCode;
-	};
 	[[nodiscard]] bool ShouldBreakThreads() const
 	{
 		return this->m_pauseThreads;
@@ -118,18 +54,8 @@ public:
 		return m_reason;
 	};
 
-	void RemoveTemporarily()
+	void RemoveTemporarily();
-	{
+	void Restore();
-		memory_writeU32(this->m_address, this->m_origOpCode);
-		PPCRecompiler_invalidateRange(this->m_address, this->m_address + 4);
-		this->m_restoreAfterInterrupt = true;
-	};
-	void Restore()
-	{
-		memory_writeU32(this->m_address, DEBUGGER_BP_T_GDBSTUB_TW);
-		PPCRecompiler_invalidateRange(this->m_address, this->m_address + 4);
-		this->m_restoreAfterInterrupt = false;
-	};
 	void PauseOnNextInterrupt()
 	{
 		this->m_pauseOnNextInterrupt = true;
@@ -162,115 +88,8 @@ enum class AccessPointType
 
 class GDBServer::AccessBreakpoint {
 public:
-	AccessBreakpoint(MPTR address, AccessPointType type)
+	AccessBreakpoint(MPTR address, AccessPointType type);
-		: m_address(address), m_type(type)
+	~AccessBreakpoint();
-	{
-#if defined(ARCH_X86_64) && BOOST_OS_WINDOWS
-		for (auto& hThreadNH : coreinit::OSGetSchedulerThreads())
-		{
-			HANDLE hThread = (HANDLE)hThreadNH;
-			CONTEXT ctx{};
-			ctx.ContextFlags = CONTEXT_DEBUG_REGISTERS;
-			SuspendThread(hThread);
-			GetThreadContext(hThread, &ctx);
-
-			// use BP 2/3 for gdb stub since cemu's internal debugger uses BP 0/1 already
-			ctx.Dr2 = (DWORD64)memory_getPointerFromVirtualOffset(address);
-			ctx.Dr3 = (DWORD64)memory_getPointerFromVirtualOffset(address);
-			// breakpoint 2
-			SetBits(ctx.Dr7, 4, 1, 1);	// breakpoint #3 enabled: true
-			SetBits(ctx.Dr7, 24, 2, 1); // breakpoint #3 condition: 1 (write)
-			SetBits(ctx.Dr7, 26, 2, 3); // breakpoint #3 length: 3 (4 bytes)
-			// breakpoint 3
-			SetBits(ctx.Dr7, 6, 1, 1);	// breakpoint #4 enabled: true
-			SetBits(ctx.Dr7, 28, 2, 3); // breakpoint #4 condition: 3 (read & write)
-			SetBits(ctx.Dr7, 30, 2, 3); // breakpoint #4 length: 3 (4 bytes)
-
-			SetThreadContext(hThread, &ctx);
-			ResumeThread(hThread);
-		}
-		// todo: port the following code to all unix platforms, they seem to differ quite a bit
-#elif defined(ARCH_X86_64) && BOOST_OS_LINUX && FALSE
-		for (auto& hThreadNH : coreinit::OSGetSchedulerThreads())
-		{
-			pid_t pid = (pid_t)(uintptr_t)hThreadNH;
-			ptrace(PTRACE_ATTACH, pid, nullptr, nullptr);
-			waitpid(pid, nullptr, 0);
-
-			DRType dr7 = _GetDR(pid, 7);
-			// use BP 2/3 for gdb stub since cemu's internal debugger uses BP 0/1 already
-			DRType dr2 = (uint64)memory_getPointerFromVirtualOffset(address);
-			DRType dr3 = (uint64)memory_getPointerFromVirtualOffset(address);
-			// breakpoint 2
-			SetBits(dr7, 4, 1, 1);  // breakpoint #3 enabled: true
-			SetBits(dr7, 24, 2, 1); // breakpoint #3 condition: 1 (write)
-			SetBits(dr7, 26, 2, 3); // breakpoint #3 length: 3 (4 bytes)
-			// breakpoint 3
-			SetBits(dr7, 6, 1, 1);  // breakpoint #4 enabled: true
-			SetBits(dr7, 28, 2, 3); // breakpoint #4 condition: 3 (read & write)
-			SetBits(dr7, 30, 2, 3); // breakpoint #4 length: 3 (4 bytes)
-
-			_SetDR(pid, 2, dr2);
-			_SetDR(pid, 3, dr3);
-			_SetDR(pid, 7, dr7);			
-			ptrace(PTRACE_DETACH, pid, nullptr, nullptr);
-		}
-#else
-		cemuLog_log(LogType::Force, "Debugger read/write breakpoints are not supported on non-x86 CPUs yet.");
-#endif
-	};
-	~AccessBreakpoint()
-	{
-#if defined(ARCH_X86_64) && BOOST_OS_WINDOWS
-		for (auto& hThreadNH : coreinit::OSGetSchedulerThreads())
-		{
-			HANDLE hThread = (HANDLE)hThreadNH;
-			CONTEXT ctx{};
-			ctx.ContextFlags = CONTEXT_DEBUG_REGISTERS;
-			SuspendThread(hThread);
-			GetThreadContext(hThread, &ctx);
-
-			// reset BP 2/3 to zero
-			ctx.Dr2 = (DWORD64)0;
-			ctx.Dr3 = (DWORD64)0;
-			// breakpoint 2
-			SetBits(ctx.Dr7, 4, 1, 0);
-			SetBits(ctx.Dr7, 24, 2, 0);
-			SetBits(ctx.Dr7, 26, 2, 0);
-			// breakpoint 3
-			SetBits(ctx.Dr7, 6, 1, 0);
-			SetBits(ctx.Dr7, 28, 2, 0);
-			SetBits(ctx.Dr7, 30, 2, 0);
-			SetThreadContext(hThread, &ctx);
-			ResumeThread(hThread);
-		}
-#elif defined(ARCH_X86_64) && BOOST_OS_LINUX && FALSE
-		for (auto& hThreadNH : coreinit::OSGetSchedulerThreads())
-		{
-			pid_t pid = (pid_t)(uintptr_t)hThreadNH;
-			ptrace(PTRACE_ATTACH, pid, nullptr, nullptr);
-			waitpid(pid, nullptr, 0);
-
-			DRType dr7 = _GetDR(pid, 7);
-			// reset BP 2/3 to zero
-			DRType dr2 = 0;
-			DRType dr3 = 0;
-			// breakpoint 2
-			SetBits(dr7, 4, 1, 0);
-			SetBits(dr7, 24, 2, 0);
-			SetBits(dr7, 26, 2, 0);
-			// breakpoint 3
-			SetBits(dr7, 6, 1, 0);
-			SetBits(dr7, 28, 2, 0);
-			SetBits(dr7, 30, 2, 0);
-
-			_SetDR(pid, 2, dr2);
-			_SetDR(pid, 3, dr3);
-			_SetDR(pid, 7, dr7);
-			ptrace(PTRACE_DETACH, pid, nullptr, nullptr);
-		}
-#endif
-	};
 
 	MPTR GetAddress() const
 	{

src/Cafe/HW/Espresso/Debugger/GDBStub.cpp

@@ -263,6 +263,14 @@ bool GDBServer::Initialize()
 		return false;
 	}
 
+	int nodelayEnabled = TRUE;
+	if (setsockopt(m_server_socket, IPPROTO_TCP, TCP_NODELAY, (char*)&nodelayEnabled, sizeof(nodelayEnabled)) == SOCKET_ERROR)
+	{
+		closesocket(m_server_socket);
+		m_server_socket = INVALID_SOCKET;
+		return false;
+	}
+
 	memset(&m_server_addr, 0, sizeof(m_server_addr));
 	m_server_addr.sin_family = AF_INET;
 	m_server_addr.sin_addr.s_addr = htonl(INADDR_ANY);

src/Cafe/OS/libs/coreinit/coreinit_Thread.cpp

@@ -5,6 +5,7 @@
 #include "Cafe/OS/libs/coreinit/coreinit_Time.h"
 #include "Cafe/OS/libs/coreinit/coreinit_Alarm.h"
 #include "Cafe/OS/libs/snd_core/ax.h"
+#include "Cafe/HW/Espresso/Debugger/GDBStub.h"
 #include "Cafe/HW/Espresso/Interpreter/PPCInterpreterInternal.h"
 #include "Cafe/HW/Espresso/Recompiler/PPCRecompiler.h"
 
@@ -1153,6 +1154,18 @@ namespace coreinit
 		}
 	}
 
+#if BOOST_OS_LINUX
+	#include <unistd.h>
+	#include <sys/prctl.h>
+
+	std::vector<pid_t> g_schedulerThreadIds;
+
+	std::vector<pid_t>& OSGetSchedulerThreadIds()
+	{
+		return g_schedulerThreadIds;
+	}
+#endif
+
 	void OSSchedulerCoreEmulationThread(void* _assignedCoreIndex)
 	{
 		SetThreadName(fmt::format("OSSchedulerThread[core={}]", (uintptr_t)_assignedCoreIndex).c_str());
@@ -1160,6 +1173,19 @@ namespace coreinit
         #if defined(ARCH_X86_64)
 		_mm_setcsr(_mm_getcsr() | 0x8000); // flush denormals to zero
         #endif
+
+#if BOOST_OS_LINUX
+		if (g_gdbstub)
+		{
+			// need to allow the GDBStub to attach to our thread
+			prctl(PR_SET_DUMPABLE, (unsigned long)1);
+			prctl(PR_SET_PTRACER, PR_SET_PTRACER_ANY);
+		}
+
+		pid_t tid = gettid();
+		g_schedulerThreadIds.emplace_back(tid);
+#endif
+
 		t_schedulerFiber = Fiber::PrepareCurrentThread();
 
 		// create scheduler idle fiber and switch to it
@@ -1211,6 +1237,9 @@ namespace coreinit
 			threadItr.join();
 		sSchedulerThreads.clear();
 		g_schedulerThreadHandles.clear();
+#if BOOST_OS_LINUX
+		g_schedulerThreadIds.clear();
+#endif
 		// clean up all fibers
 		for (auto& it : g_idleLoopFiber)
 		{

src/Common/ExceptionHandler/ExceptionHandler_posix.cpp

@@ -6,6 +6,9 @@
 #include "util/helpers/StringHelpers.h"
 #include "ExceptionHandler.h"
 
+#include "Cafe/HW/Espresso/Debugger/GDBStub.h"
+#include "Cafe/HW/Espresso/Debugger/GDBBreakpoints.h"
+
 #if BOOST_OS_LINUX
 #include "ELFSymbolTable.h"
 #endif
@@ -61,6 +64,16 @@ void DemangleAndPrintBacktrace(char** backtrace, size_t size)
 // handle signals that would dump core, print stacktrace and then dump depending on config
 void handlerDumpingSignal(int sig, siginfo_t *info, void *context)
 {
+#if defined(ARCH_X86_64) && BOOST_OS_LINUX
+	// Check for hardware breakpoints
+	if (info->si_signo == SIGTRAP && info->si_code == TRAP_HWBKPT)
+	{
+		uint64 dr6 = _ReadDR6();
+		g_gdbstub->HandleAccessException(dr6);
+		return;
+	}
+#endif
+
     if(!CrashLog_Create())
         return; // give up if crashlog was already created