server/gdb_server: Add support for default thread, use by IDA debugger

Signed-off-by: Benoit Forgette <benoit.forgette@ci-yow.com>
Change-Id: Ia3a29a3377be650f0ccad11a0ae4fe4da78b3ab4
Reviewed-on: https://review.openocd.org/c/openocd/+/7017
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

1 files changed, 92 insertions, 93 deletions

diff --git a/src/server/gdb_server.c b/src/server/gdb_server.c
index 1e50b43..5cffa23 100644
--- a/src/server/gdb_server.c
+++ b/src/server/gdb_server.c
@@ -3030,128 +3030,127 @@ static bool gdb_handle_vcont_packet(struct connection *connection, const char *p
 		gdb_running_type = 's';
 		bool fake_step = false;
 
-		if (strncmp(parse, "s:", 2) == 0) {
-			struct target *ct = target;
-			int current_pc = 1;
-			int64_t thread_id;
+		struct target *ct = target;
+		int current_pc = 1;
+		int64_t thread_id;
+		parse++;
+		packet_size--;
+		if (parse[0] == ':') {
 			char *endp;
-
-			parse += 2;
-			packet_size -= 2;
-
+			parse++;
+			packet_size--;
 			thread_id = strtoll(parse, &endp, 16);
 			if (endp) {
 				packet_size -= endp - parse;
 				parse = endp;
 			}
+		} else {
+			thread_id = 0;
+		}
+
+		if (target->rtos) {
+			/* FIXME: why is this necessary? rtos state should be up-to-date here already! */
+			rtos_update_threads(target);
 
-			if (target->rtos) {
-				/* FIXME: why is this necessary? rtos state should be up-to-date here already! */
-				rtos_update_threads(target);
+			target->rtos->gdb_target_for_threadid(connection, thread_id, &ct);
 
-				target->rtos->gdb_target_for_threadid(connection, thread_id, &ct);
+			/*
+			 * check if the thread to be stepped is the current rtos thread
+			 * if not, we must fake the step
+			 */
+			if (target->rtos->current_thread != thread_id)
+				fake_step = true;
+		}
 
-				/*
-				 * check if the thread to be stepped is the current rtos thread
-				 * if not, we must fake the step
-				 */
-				if (target->rtos->current_thread != thread_id)
-					fake_step = true;
-			}
+		if (parse[0] == ';') {
+			++parse;
+			--packet_size;
 
-			if (parse[0] == ';') {
-				++parse;
-				--packet_size;
+			if (parse[0] == 'c') {
+				parse += 1;
 
-				if (parse[0] == 'c') {
+				/* check if thread-id follows */
+				if (parse[0] == ':') {
+					int64_t tid;
 					parse += 1;
 
-					/* check if thread-id follows */
-					if (parse[0] == ':') {
-						int64_t tid;
-						parse += 1;
-
-						tid = strtoll(parse, &endp, 16);
-						if (tid == thread_id) {
-							/*
-							 * Special case: only step a single thread (core),
-							 * keep the other threads halted. Currently, only
-							 * aarch64 target understands it. Other target types don't
-							 * care (nobody checks the actual value of 'current')
-							 * and it doesn't really matter. This deserves
-							 * a symbolic constant and a formal interface documentation
-							 * at a later time.
-							 */
-							LOG_DEBUG("request to step current core only");
-							/* uncomment after checking that indeed other targets are safe */
-							/*current_pc = 2;*/
-						}
+					tid = strtoll(parse, NULL, 16);
+					if (tid == thread_id) {
+						/*
+						 * Special case: only step a single thread (core),
+						 * keep the other threads halted. Currently, only
+						 * aarch64 target understands it. Other target types don't
+						 * care (nobody checks the actual value of 'current')
+						 * and it doesn't really matter. This deserves
+						 * a symbolic constant and a formal interface documentation
+						 * at a later time.
+						 */
+						LOG_DEBUG("request to step current core only");
+						/* uncomment after checking that indeed other targets are safe */
+						/*current_pc = 2;*/
 					}
 				}
 			}
+		}
 
-			LOG_DEBUG("target %s single-step thread %"PRIx64, target_name(ct), thread_id);
-			gdb_connection->output_flag = GDB_OUTPUT_ALL;
-			target_call_event_callbacks(ct, TARGET_EVENT_GDB_START);
-
-			/*
-			 * work around an annoying gdb behaviour: when the current thread
-			 * is changed in gdb, it assumes that the target can follow and also
-			 * make the thread current. This is an assumption that cannot hold
-			 * for a real target running a multi-threading OS. We just fake
-			 * the step to not trigger an internal error in gdb. See
-			 * https://sourceware.org/bugzilla/show_bug.cgi?id=22925 for details
-			 */
-			if (fake_step) {
-				int sig_reply_len;
-				char sig_reply[128];
-
-				LOG_DEBUG("fake step thread %"PRIx64, thread_id);
+		LOG_DEBUG("target %s single-step thread %"PRIx64, target_name(ct), thread_id);
+		gdb_connection->output_flag = GDB_OUTPUT_ALL;
+		target_call_event_callbacks(ct, TARGET_EVENT_GDB_START);
 
-				sig_reply_len = snprintf(sig_reply, sizeof(sig_reply),
-										 "T05thread:%016"PRIx64";", thread_id);
+		/*
+		 * work around an annoying gdb behaviour: when the current thread
+		 * is changed in gdb, it assumes that the target can follow and also
+		 * make the thread current. This is an assumption that cannot hold
+		 * for a real target running a multi-threading OS. We just fake
+		 * the step to not trigger an internal error in gdb. See
+		 * https://sourceware.org/bugzilla/show_bug.cgi?id=22925 for details
+		 */
+		if (fake_step) {
+			int sig_reply_len;
+			char sig_reply[128];
 
-				gdb_put_packet(connection, sig_reply, sig_reply_len);
-				gdb_connection->output_flag = GDB_OUTPUT_NO;
+			LOG_DEBUG("fake step thread %"PRIx64, thread_id);
 
-				return true;
-			}
+			sig_reply_len = snprintf(sig_reply, sizeof(sig_reply),
+									"T05thread:%016"PRIx64";", thread_id);
 
-			/* support for gdb_sync command */
-			if (gdb_connection->sync) {
-				gdb_connection->sync = false;
-				if (ct->state == TARGET_HALTED) {
-					LOG_DEBUG("stepi ignored. GDB will now fetch the register state "
-									"from the target.");
-					gdb_sig_halted(connection);
-					gdb_connection->output_flag = GDB_OUTPUT_NO;
-				} else
-					gdb_connection->frontend_state = TARGET_RUNNING;
-				return true;
-			}
+			gdb_put_packet(connection, sig_reply, sig_reply_len);
+			gdb_connection->output_flag = GDB_OUTPUT_NO;
 
-			retval = target_step(ct, current_pc, 0, 0);
-			if (retval == ERROR_TARGET_NOT_HALTED)
-				LOG_INFO("target %s was not halted when step was requested", target_name(ct));
+			return true;
+		}
 
-			/* if step was successful send a reply back to gdb */
-			if (retval == ERROR_OK) {
-				retval = target_poll(ct);
-				if (retval != ERROR_OK)
-					LOG_DEBUG("error polling target %s after successful step", target_name(ct));
-				/* send back signal information */
-				gdb_signal_reply(ct, connection);
-				/* stop forwarding log packets! */
+		/* support for gdb_sync command */
+		if (gdb_connection->sync) {
+			gdb_connection->sync = false;
+			if (ct->state == TARGET_HALTED) {
+				LOG_DEBUG("stepi ignored. GDB will now fetch the register state "
+								"from the target.");
+				gdb_sig_halted(connection);
 				gdb_connection->output_flag = GDB_OUTPUT_NO;
 			} else
 				gdb_connection->frontend_state = TARGET_RUNNING;
-		} else {
-			LOG_ERROR("Unknown vCont packet");
-			return false;
+			return true;
 		}
+
+		retval = target_step(ct, current_pc, 0, 0);
+		if (retval == ERROR_TARGET_NOT_HALTED)
+			LOG_INFO("target %s was not halted when step was requested", target_name(ct));
+
+		/* if step was successful send a reply back to gdb */
+		if (retval == ERROR_OK) {
+			retval = target_poll(ct);
+			if (retval != ERROR_OK)
+				LOG_DEBUG("error polling target %s after successful step", target_name(ct));
+			/* send back signal information */
+			gdb_signal_reply(ct, connection);
+			/* stop forwarding log packets! */
+			gdb_connection->output_flag = GDB_OUTPUT_NO;
+		} else
+			gdb_connection->frontend_state = TARGET_RUNNING;
 		return true;
 	}
-
+	LOG_ERROR("Unknown vCont packet");
 	return false;
 }