diff --git a/gdbstub/gdbstub b/gdbstub/gdbstub
index b00d0f81..8ce6abf8 160000
--- a/gdbstub/gdbstub
+++ b/gdbstub/gdbstub
@@ -1 +1 @@
-Subproject commit b00d0f815b3996a13ce87a4d9d6d7038353e77e6
+Subproject commit 8ce6abf8d32291ad66a3724123a9a583b9a3bb4b
diff --git a/gdbstub/gdbstub_sys.c b/gdbstub/gdbstub_sys.c
index bfba9bf7..7773de67 100644
--- a/gdbstub/gdbstub_sys.c
+++ b/gdbstub/gdbstub_sys.c
@@ -3,8 +3,24 @@
 #include "libpcsxcore/socket.h"
 #include "libpcsxcore/r3000a.h"
 #include <stdio.h>
+#include <stdlib.h>
+#include <stddef.h>
+
+#ifdef _POSIX_VERSION
+#include <pthread.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <mqueue.h>
+#include <errno.h>
+
+static pthread_t thread;
+static mqd_t in_queue, out_queue;
+#endif
 
 static int server_socket, client_socket;
+static enum {
+    PAUSED,
+} state;
 
 static void update_regs(struct dbg_state *const dbg_state)
 {
@@ -56,13 +72,6 @@ static void update_regs(struct dbg_state *const dbg_state)
 	dbg_state->registers[DBG_CPU_MIPS_I_REG_PC] = psxRegs.pc;
 }
 
-void dbg_sys_process(void)
-{
-    static struct dbg_state dbg_state;
-    update_regs(&dbg_state);
-    dbg_main(&dbg_state);
-}
-
 int dbg_sys_getc(void)
 {
     while (1) {
@@ -74,15 +83,22 @@ int dbg_sys_getc(void)
             case READ_SOCKET_OK:
                 return packet;
 
-            case READ_SOCKET_SHUTDOWN:
+            case READ_SOCKET_SHUTDOWN: {
+                struct msg msg;
+
+                printf("gdb shutdown\n");
                 client_socket = 0;
+                msg.type = MSG_TYPE_SHUTDOWN;
+
+                    if (mq_send(out_queue, (const char *)&msg, sizeof msg, 0))
+                        perror("dbg_sys_getc() mq_send()");
                 return EOF;
+            }
 
             case READ_SOCKET_ERR_INVALID_ARG:
                 /* Fall through. */
             case READ_SOCKET_ERR_RECV:
                 /* Fall through. */
-
             default:
                 break;
         }
@@ -106,27 +122,247 @@ int dbg_sys_mem_writeb(address addr, char val)
     return 0;
 }
 
+#ifdef _POSIX_VERSION
+static int wait_hit_or_break(struct msg *msg)
+{
+    do {
+        int ret = mq_receive(in_queue, (char *)msg, sizeof *msg, 0);
+
+        if (ret < 0 && errno == EAGAIN) {
+            /* Breakpoint has not been hit yet, look for incoming messages from gdb. */
+            char packet;
+            size_t len = sizeof packet;
+            const enum read_socket_err err = ReadSocket(client_socket, &packet, &len);
+
+            switch (err) {
+                case READ_SOCKET_OK:
+                    if (len && packet == 0x03)
+                        return 0;
+
+                    break;
+
+                case READ_SOCKET_SHUTDOWN:
+                    printf("gdb shutdown\n");
+                    client_socket = 0;
+                    msg->type = MSG_TYPE_SHUTDOWN;
+
+                    if (mq_send(out_queue, (const char *)msg, sizeof *msg, 0))
+                        perror("wait_hit_or_break() mq_send()");
+
+                    return EOF;
+
+                case READ_SOCKET_ERR_INVALID_ARG:
+                    /* Fall through. */
+                case READ_SOCKET_ERR_RECV:
+                    /* Fall through. */
+                default:
+                    break;
+            }
+        }
+        else if (msg->type != MSG_TYPE_HIT) {
+            fprintf(stderr, "unexpected msg.type %d\n", msg->type);
+            return 1;
+        }
+        else
+            return 0;
+    } while (1);
+
+    return 1;
+}
+#endif
+
+#ifdef _POSIX_VERSION
 int dbg_sys_continue(void)
 {
-    return 0;
-}
+    struct msg msg;
 
+    msg.type = MSG_TYPE_CONTINUE;
+
+    if (mq_send(out_queue, (const char *)&msg, sizeof msg, 0)) {
+        perror("dbg_sys_continue(): mq_send()");
+        return 1;
+    }
+
+    return wait_hit_or_break(&msg);
+}
+#endif
+
+#ifdef _POSIX_VERSION
 int dbg_sys_step(void)
 {
+    struct msg msg;
+
+    msg.type = MSG_TYPE_STEP;
+
+    if (mq_send(out_queue, (const char *)&msg, sizeof msg, 0)) {
+        perror("dbg_sys_step(): mq_send()");
+    }
+
+    return wait_hit_or_break(&msg);
+}
+#endif
+
+#ifdef _POSIX_VERSION
+static int wait_ack(struct msg *msg)
+{
+    int ret;
+
+    do {
+        ret = mq_receive(in_queue, (char *)msg, sizeof *msg, 0);
+    } while (ret < 0 && errno == EAGAIN);
+
+    if (msg->type != MSG_TYPE_ACK) {
+        fprintf(stderr, "unexpected msg.type %d\n", msg->type);
+        return 1;
+    }
+
     return 0;
 }
+#endif
+
+#ifdef _POSIX_VERSION
+int dbg_sys_breakpoint(address addr)
+{
+    struct msg msg;
+
+    msg.type = MSG_TYPE_BREAKPOINT;
+    msg.data.breakpoint.addr = addr;
+
+    if (mq_send(out_queue, (const char *)&msg, sizeof msg, 0)) {
+        perror("dbg_sys_breakpoint(): mq_send()");
+    }
+
+    return wait_ack(&msg);
+}
+#endif
+
+#ifdef _POSIX_VERSION
+int dbg_sys_del_breakpoint(address addr)
+{
+    struct msg msg;
+
+    msg.type = MSG_TYPE_REMOVE_BREAKPOINT;
+
+    if (mq_send(out_queue, (const char *)&msg, sizeof msg, 0)) {
+        perror("dbg_sys_breakpoint(): mq_send()");
+    }
+
+    return wait_ack(&msg);
+}
+#endif
+
+#ifdef _POSIX_VERSION
+static int queue_create(void)
+{
+    struct mq_attr attr;
+
+    attr.mq_msgsize = sizeof (struct msg);
+    attr.mq_flags = 0;
+    attr.mq_maxmsg = 4;
+
+    mq_unlink("/pcsxrin");
+    in_queue = mq_open("/pcsxrin", O_CREAT | O_RDWR | O_EXCL | O_NONBLOCK, 0600, &attr);
+
+    mq_unlink("/pcsxrout");
+    out_queue = mq_open("/pcsxrout", O_CREAT | O_RDWR | O_EXCL, 0600, &attr);
+
+    if ((out_queue < 0) || (in_queue < 0)) {
+        perror("mq_open()");
+        return 1;
+    }
+
+    return 0;
+}
+#endif
+
+static int exit_loop;
+
+static void *loop(void *const args)
+{
+    struct dbg_state dbg_state = {0};
+
+    SetsBlock(server_socket);
+
+    if ((client_socket = GetClient(server_socket, 1)) < 0) {
+        fprintf(stderr, "GetClient() failed\n");
+        return NULL;
+    }
+
+    SetsNonblock(client_socket);
+
+    printf("Accepted gdb connection\n");
+
+    while (!exit_loop) {
+        update_regs(&dbg_state);
+        dbg_main(&dbg_state);
+    }
+
+    return NULL;
+}
+
+#ifdef _POSIX_VERSION
+static void start_thread(void)
+{
+    if (pthread_create(&thread, NULL, loop, NULL))
+        perror("could not start gdb server thread");
+}
+#endif
+
+#ifdef _POSIX_VERSION
+static void stop_thread(void)
+{
+    if (pthread_join(thread, NULL))
+        perror("pthread_join()");
+
+    mq_unlink("/pcsxrin");
+    mq_unlink("/pcsxrout");
+}
+#endif
+
+#ifdef _POSIX_VERSION
+void gdbstub_sys_recv(struct msg *msg)
+{
+    const ssize_t sz = mq_receive(out_queue, (char *)msg, sizeof *msg, 0);
+
+    if (sz < 0)
+        perror("mq_receive");
+}
+#endif
+
+#ifdef _POSIX_VERSION
+void gdbstub_sys_send(const struct msg *msg)
+{
+    if (mq_send(in_queue, (const char *)msg, sizeof *msg, 0)) {
+        perror("dbg_sys_send(): mq_send()");
+    }
+}
+#endif
+
+void dbg_stop(void)
+{
+    exit_loop = 1;
+    stop_thread();
+}
 
 void dbg_start(void)
 {
-    const unsigned short port = 3333;
+    if (server_socket > 0) {
+        fprintf(stderr, "gdb server already started\n");
+        return;
+    }
+    else {
+        const unsigned short port = 3333;
 
-    if (server_socket > 0)
-        StopServer(server_socket);
+        server_socket = StartServer(port);
 
-    server_socket = StartServer(port);
-
-    if (server_socket > 0)
-        printf("GDB server started on port %hu.\n", port);
-    else
-        fprintf(stderr, "Could not start GDB server\n");
+        if (server_socket > 0) {
+            printf("GDB server started on port %hu.\n", port);
+            if (queue_create())
+                fprintf(stderr, "could not create gdb stub internal queues\n");
+            else
+                start_thread();
+        }
+        else
+            fprintf(stderr, "could not start GDB server\n");
+    }
 }
diff --git a/gdbstub/gdbstub_sys.h b/gdbstub/gdbstub_sys.h
index 84bae1fa..f44dfcc9 100644
--- a/gdbstub/gdbstub_sys.h
+++ b/gdbstub/gdbstub_sys.h
@@ -42,7 +42,11 @@ enum DBG_REGISTER {
 	DBG_CPU_MIPS_I_REG_BAD,
 	DBG_CPU_MIPS_I_REG_CAUSE,
 	DBG_CPU_MIPS_I_REG_PC,
-	DBG_CPU_NUM_REGISTERS
+
+	/* GDB requests 73, where 38 are the ones above and the rest
+	 * are the floating-point registers. This way, unused registers
+	 * are left to zero. */
+	DBG_CPU_NUM_REGISTERS = 73
 };
 
 typedef unsigned int reg;
@@ -52,7 +56,29 @@ struct dbg_state {
 	reg registers[DBG_CPU_NUM_REGISTERS];
 };
 
+struct msg {
+	enum {
+		MSG_TYPE_CONTINUE,
+		MSG_TYPE_BREAKPOINT,
+		MSG_TYPE_STEP,
+		MSG_TYPE_ACK,
+		MSG_TYPE_REMOVE_BREAKPOINT,
+		MSG_TYPE_SHUTDOWN,
+
+		/* Response frames. */
+		MSG_TYPE_HIT
+	} type;
+
+	union {
+		struct {
+			address addr;
+		} breakpoint;
+	} data;
+};
+
 void dbg_start(void);
-void dbg_sys_process(void);
+void dbg_stop(void);
+void gdbstub_sys_send(const struct msg *msg);
+void gdbstub_sys_recv(struct msg *msg);
 
 #endif /* GDBSTUB_SYS_H */
diff --git a/gui/LnxMain.c b/gui/LnxMain.c
index 12aeb5fc..2e087ee3 100644
--- a/gui/LnxMain.c
+++ b/gui/LnxMain.c
@@ -321,6 +321,11 @@ int main(int argc, char *argv[]) {
 			SetIsoFile(isofilename);
 			runcd = RUN_CD;
 		}
+		else if (!strcmp(argv[i], "-gdb")) {
+			/* Force configuration. */
+			Config.Cpu = CPU_INTERPRETER;
+			Config.GdbServer = 1;
+		}
 		else if (!strcmp(argv[i], "-h") ||
 			 !strcmp(argv[i], "-help") ||
 			 !strcmp(argv[i], "--help")) {
@@ -461,6 +466,8 @@ int main(int argc, char *argv[]) {
 		psxCpu->Execute();
 	}
 
+	if (Config.GdbServer) dbg_stop();
+
 	return 0;
 }
 
diff --git a/libpcsxcore/debug.c b/libpcsxcore/debug.c
index 463df73b..ecc9edc7 100644
--- a/libpcsxcore/debug.c
+++ b/libpcsxcore/debug.c
@@ -397,7 +397,7 @@ void DebugVSync() {
 
     if (client_socket < 1)
     {
-        client_socket = GetClient(server_socket);
+        client_socket = GetClient(server_socket, 0);
 
         if (client_socket > 0)
         {
@@ -478,7 +478,7 @@ void ProcessDebug() {
 
         if (client_socket < 1)
         {
-            client_socket = GetClient(server_socket);
+            client_socket = GetClient(server_socket, 0);
 
             if (client_socket > 0)
             {
diff --git a/libpcsxcore/psxinterpreter.c b/libpcsxcore/psxinterpreter.c
index a2bc0e1d..941fda4b 100644
--- a/libpcsxcore/psxinterpreter.c
+++ b/libpcsxcore/psxinterpreter.c
@@ -1198,6 +1198,68 @@ static void intClear(u32 Addr, u32 Size) {
 static void intShutdown() {
 }
 
+static void process_gdb(void) {
+	static int shutdown;
+	static u32 tgt_addr;
+	static int step, must_continue;
+	struct msg msg;
+
+	if (shutdown)
+		return;
+
+	if (step || (must_continue && tgt_addr && tgt_addr == psxRegs.pc)) {
+		msg.type = MSG_TYPE_HIT;
+#if DEBUG == 1
+		printf("hit address 0x%08X\n", psxRegs.pc);
+#endif
+		gdbstub_sys_send(&msg);
+		must_continue = 0;
+		step = 0;
+	}
+
+	if (!must_continue) {
+		gdbstub_sys_recv(&msg);
+
+		switch (msg.type) {
+			case MSG_TYPE_CONTINUE:
+				must_continue = 1;
+				break;
+
+			case MSG_TYPE_STEP:
+				step = 1;
+				break;
+
+			case MSG_TYPE_REMOVE_BREAKPOINT: {
+				struct msg out;
+
+				tgt_addr = 0;
+				out.type = MSG_TYPE_ACK;
+
+				gdbstub_sys_send(&out);
+			}
+				break;
+
+			case MSG_TYPE_BREAKPOINT: {
+				struct msg out;
+
+				tgt_addr = msg.data.breakpoint.addr;
+				out.type = MSG_TYPE_ACK;
+
+				gdbstub_sys_send(&out);
+			}
+				break;
+
+			case MSG_TYPE_SHUTDOWN:
+				shutdown = 1;
+				break;
+
+			default:
+				fprintf(stderr, "unknown msg.type %d\n", msg.type);
+				break;
+		}
+	}
+}
+
 // interpreter execution
 static inline void execI() {
 	u32 *code = Read_ICache(psxRegs.pc, FALSE);
@@ -1205,7 +1267,7 @@ static inline void execI() {
 
 	debugI();
 
-	if (Config.GdbServer) dbg_sys_process();
+	if (Config.GdbServer) process_gdb();
 	else if (Config.Debug) ProcessDebug();
 
 	psxRegs.pc += 4;
diff --git a/libpcsxcore/socket.c b/libpcsxcore/socket.c
index 51aefdf7..eec4c96a 100644
--- a/libpcsxcore/socket.c
+++ b/libpcsxcore/socket.c
@@ -88,7 +88,7 @@ void StopServer(int s_socket) {
 #endif
 }
 
-int GetClient(int s_socket) {
+int GetClient(int s_socket, int blocking) {
     int new_socket = accept(s_socket, NULL, NULL);
 
 #ifdef _WIN32
@@ -100,6 +100,7 @@ int GetClient(int s_socket) {
 #endif
 
 #ifndef _WIN32
+    if (!blocking)
     {
         int flags;
         flags = fcntl(new_socket, F_GETFL, 0);
diff --git a/libpcsxcore/socket.h b/libpcsxcore/socket.h
index 531a6485..852c76a4 100644
--- a/libpcsxcore/socket.h
+++ b/libpcsxcore/socket.h
@@ -35,7 +35,7 @@ enum read_socket_err
 int StartServer(unsigned short port);
 void StopServer(int s_socket);
 
-int GetClient(int s_socket);
+int GetClient(int s_socket, int blocking);
 void CloseClient(int client_socket);
 
 int HasClient(int client_socket);
diff --git a/win32/gui/WndMain.c b/win32/gui/WndMain.c
index 374b1877..4c01b200 100644
--- a/win32/gui/WndMain.c
+++ b/win32/gui/WndMain.c
@@ -238,6 +238,8 @@ int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine
 
 	RunGui();
 
+	if (Config.GdbServer) dbg_stop();
+
 	return 0;
 }
 
@@ -1570,7 +1572,7 @@ BOOL CALLBACK ConfigureCpuDlgProc(HWND hW, UINT uMsg, WPARAM wParam, LPARAM lPar
 					}
 
 					if (Config.GdbServer) {
-						GdbStartServer();
+						dbg_start();
 					}
 
 					SaveConfig();
@@ -1996,8 +1998,7 @@ int SysInit() {
 	LoadMcds(Config.Mcd1, Config.Mcd2);
 
 	if (Config.Debug) StartDebugger();
-
-	if (Config.GdbServer) GdbStartServer();
+	else if (Config.GdbServer) dbg_start();
 
 	return 0;
 }