diff --git a/tools/gdb/serial.c b/tools/gdb/serial.c
new file mode 100644
index 0000000000..88895bb9f8
--- /dev/null
+++ b/tools/gdb/serial.c
@@ -0,0 +1,126 @@
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/time.h>
+#include "serial.h"
+
+#if defined(__sun__)	 || \
+    defined(__OpenBSD__) || \
+    defined(__FreeBSD__) || \
+    defined(__NetBSD__)	 || \
+    defined(__APPLE__)
+static struct termios tios = { BRKINT, 0, B115200|CS8|CREAD, 0, { 0 } };
+#else
+static struct termios tios = { BRKINT, 0, B115200|CS8|CREAD, 0,   0   };
+#endif
+
+static struct speedmap {
+    char *str;
+    speed_t val;
+} speedmap[] = {
+    { "50", B50 },		{ "75", B75 },		{ "110", B110 },
+    { "134", B134 },		{ "150", B150 },	{ "200", B200 },
+    { "300", B300 },		{ "600", B600 },	{ "1200", B1200 },
+    { "1800", B1800 },		{ "2400", B2400 },	{ "4800", B4800 },
+    { "9600", B9600 },		{ "19200", B19200 },	{ "38400", B38400 },
+    { "57600", B57600 },
+#ifdef	B76800
+    { "76800", B76800 },
+#endif
+    { "115200", B115200 },
+#ifdef	B153600
+    { "153600", B153600 },
+#endif
+    { "230400", B230400 },
+#ifdef	B307200
+    { "307200", B307200 },
+#endif
+#ifdef B460800
+    { "460800", B460800 }
+#endif
+};
+static int nspeeds = sizeof speedmap / sizeof speedmap[0];
+
+speed_t
+cvtspeed(char *str)
+{
+    struct speedmap *smp = speedmap, *esmp = &speedmap[nspeeds];
+
+    while (smp < esmp) {
+	if (strcmp(str, smp->str) == 0)
+	    return (smp->val);
+	smp++;
+    }
+    return B0;
+}
+
+int
+serialopen(char *device, speed_t speed)
+{
+    int fd;
+
+    if (cfsetospeed(&tios, speed) < 0)
+	return -1;
+
+    if ((fd = open(device, O_RDWR)) < 0)
+	return -1;
+
+    if (tcsetattr(fd, TCSAFLUSH, &tios) < 0) {
+	(void)close(fd);
+	return -1;
+    }
+
+    return fd;
+}
+
+int
+serialreadchar(int fd, int timeout)
+{
+    fd_set fds;
+    struct timeval tv;
+    int n;
+    char ch;
+
+    tv.tv_sec = timeout;
+    tv.tv_usec = 0;
+
+    FD_ZERO(&fds);
+    FD_SET(fd, &fds);
+
+    /* this is a fucking horrible quick hack - fix this */
+
+    if ((n = select(fd + 1, &fds, 0, 0, &tv)) < 0)
+	return SERIAL_ERROR;
+
+    if (n == 0)
+	return SERIAL_TIMEOUT;
+
+    if ((n = read(fd, &ch, 1)) < 0)
+	return SERIAL_ERROR;
+
+    if (n == 0)
+	return SERIAL_EOF;
+
+    return ch;
+}
+
+int
+serialwrite(int fd, char *buf, int len)
+{
+    int n;
+
+    do {
+	n = write(fd, buf, len);
+	if (n < 0)
+	    return 1;
+	len -= n;
+	buf += n;
+    } while (len > 0);
+    return 0;
+}
+
+int
+serialclose(int fd)
+{
+    return close(fd);
+}