diff --git a/payloads/libpayload/gdb/commands.c b/payloads/libpayload/gdb/commands.c
new file mode 100644
index 0000000..5137dfd
--- /dev/null
+++ b/payloads/libpayload/gdb/commands.c
@@ -0,0 +1,101 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but without any warranty; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <arch/cache.h>
+#include <gdb.h>
+#include <libpayload.h>
+
+static void gdb_get_last_signal(struct gdb_message *command,
+				int offset, struct gdb_message *reply)
+{
+	gdb_message_add_string(reply, "S");
+	gdb_message_encode_bytes(reply, &gdb_state.signal, 1);
+}
+
+static void gdb_read_general_registers(struct gdb_message *command,
+				       int offset, struct gdb_message *reply)
+{
+	gdb_arch_encode_regs(reply);
+}
+
+static void gdb_write_general_registers(struct gdb_message *command,
+					int offset, struct gdb_message *reply)
+{
+	gdb_arch_decode_regs(offset, command);
+	gdb_message_add_string(reply, "OK");
+}
+
+static void gdb_read_memory(struct gdb_message *command,
+			    int offset, struct gdb_message *reply)
+{
+	int tok = gdb_message_tokenize(command, &offset);
+	uintptr_t addr = gdb_message_decode_int(command, tok, offset - 1 - tok);
+	size_t length = gdb_message_decode_int(command, offset,
+					       command->used - offset);
+
+	gdb_message_encode_bytes(reply, (void *)addr, length);
+}
+
+static void gdb_write_memory(struct gdb_message *command,
+			     int offset, struct gdb_message *reply)
+{
+	int tok = gdb_message_tokenize(command, &offset);
+	uintptr_t addr = gdb_message_decode_int(command, tok, offset - 1 - tok);
+	tok = gdb_message_tokenize(command, &offset);
+	size_t length = gdb_message_decode_int(command, tok, offset - 1 - tok);
+
+	die_if(length * 2 != command->used - offset, "Invalid length field in "
+	       "GDB command: %.*s", command->used, command->buf);
+
+	gdb_message_decode_bytes(command, offset, (void *)addr, length);
+	cache_sync_instructions();
+	gdb_message_add_string(reply, "OK");
+}
+
+static void gdb_continue(struct gdb_message *command,
+			 int offset, struct gdb_message *reply)
+{
+	/* Disable single step if it's still on. */
+	gdb_arch_set_single_step(0);
+
+	/* No need to support the extension that passes in new EIP/PC. */
+	if (command->used > offset)
+		gdb_message_add_string(reply, "E00");
+	else
+		gdb_state.resumed = 1;
+}
+
+static void gdb_single_step(struct gdb_message *command,
+			    int offset, struct gdb_message *reply)
+{
+	if (command->used > offset || gdb_arch_set_single_step(1))
+		gdb_message_add_string(reply, "E00");
+	else
+		gdb_state.resumed = 1;
+}
+
+struct gdb_command gdb_commands[] = {
+	{ "?", &gdb_get_last_signal },
+	{ "g", &gdb_read_general_registers },
+	{ "G", &gdb_write_general_registers },
+	{ "m", &gdb_read_memory },
+	{ "M", &gdb_write_memory },
+	{ "c", &gdb_continue },
+	{ "s", &gdb_single_step }
+};
+const int gdb_command_count = ARRAY_SIZE(gdb_commands);