gdb: fix extended-remote restart

Seems versions of gdb > 6.8 require an W stop reply after receiving a
kill packet.

Without this we receive the following error from gdb:
gdb/thread.c:72: internal-error: inferior_thread: Assertion `tp' failed.

Change-Id: I86765a321f0429c9b517fe13ded0ee2dbd4b2f87
Signed-off-by: Spencer Oliver <spen@spen-soft.co.uk>
Reviewed-on: http://openocd.zylin.com/911
Tested-by: jenkins
Reviewed-by: Joel Bodenmann <joel@unormal.org>
Reviewed-by: Freddie Chopin <freddie.chopin@gmail.com>

diff --git a/src/server/gdb_server.c b/src/server/gdb_server.c
index 640f8eaeffe6b7fbbe5b90f831a17d611599f813..047a9d098f421c99659ba876a9c333f90c3058ac 100644 (file)
--- a/src/server/gdb_server.c
+++ b/src/server/gdb_server.c
@@ -74,6 +74,11 @@ struct gdb_connection {
         * can be replied immediately and a new GDB packet will be ready without delay
         * (ca. 10% or so...). */
        bool mem_write_error;
+       /* with extended-remote it seems we need to better emulate attach/detach.
+        * what this means is we reply with a W stop reply after a kill packet,
+        * normally we reply with a S reply via gdb_last_signal_packet.
+        * as a side note this behaviour only effects gdb > 6.8 */
+       bool attached;
 };
 
 #if 0
@@ -762,6 +767,7 @@ static int gdb_new_connection(struct connection *connection)
        gdb_connection->noack_mode = 0;
        gdb_connection->sync = true;
        gdb_connection->mem_write_error = false;
+       gdb_connection->attached = true;
 
        /* send ACK to GDB for debug request */
        gdb_write(connection, "+", 1);
@@ -878,9 +884,17 @@ static int gdb_last_signal_packet(struct connection *connection,
                char *packet, int packet_size)
 {
        struct target *target = get_target_from_connection(connection);
+       struct gdb_connection *gdb_con = connection->priv;
        char sig_reply[4];
        int signal_var;
 
+       if (!gdb_con->attached) {
+               /* if we are here we have received a kill packet
+                * reply W stop reply otherwise gdb gets very unhappy */
+               gdb_put_packet(connection, "W00", 3);
+               return ERROR_OK;
+       }
+
        signal_var = gdb_last_signal(target);
 
        snprintf(sig_reply, 4, "S%2.2x", signal_var);
@@ -2160,8 +2174,10 @@ static int gdb_input_inner(struct connection *connection)
                                                return retval;
                                        break;
                                case 'k':
-                                       if (extended_protocol != 0)
+                                       if (extended_protocol != 0) {
+                                               gdb_con->attached = false;
                                                break;
+                                       }
                                        gdb_put_packet(connection, "OK", 2);
                                        return ERROR_SERVER_REMOTE_CLOSED;
                                case '!':
@@ -2175,6 +2191,8 @@ static int gdb_input_inner(struct connection *connection)
                                        watchpoint_clear_target(gdb_service->target);
                                        command_run_linef(connection->cmd_ctx, "ocd_gdb_restart %s",
                                                        target_name(target));
+                                       /* set connection as attached after reset */
+                                       gdb_con->attached = true;
                                        /*  info rtos parts */
                                        gdb_thread_packet(connection, packet, packet_size);
                                        gdb_put_packet(connection, "OK", 2);