Chapter3: power2/3/5 & sleep test worked on k210/qemu based on timer.

os/src/task/mod.rs

@@ -94,7 +94,7 @@ impl TaskManager {
                 );
             }
         } else {
-            panic!("[kernel] All applications completed!");
+            panic!("All applications completed!");
         }
     }
 }
@@ -103,14 +103,24 @@ pub fn run_first_task() {
     TASK_MANAGER.run_first_task();
 }
 
-pub fn run_next_task() {
+fn run_next_task() {
     TASK_MANAGER.run_next_task();
 }
 
-pub fn mark_current_suspended() {
+fn mark_current_suspended() {
     TASK_MANAGER.mark_current_suspended();
 }
 
-pub fn mark_current_exited() {
+fn mark_current_exited() {
     TASK_MANAGER.mark_current_exited();
+}
+
+pub fn suspend_current_and_run_next() {
+    mark_current_suspended();
+    run_next_task();
+}
+
+pub fn exit_current_and_run_next() {
+    mark_current_exited();
+    run_next_task();
 }