Exiting tasks use EXITING signal and change states to TASK_DEAD

src/api/thread.c

@@ -54,6 +54,12 @@ int thread_suspend(struct ktcb *task)
 	return thread_signal(task, TASK_SUSPENDING, TASK_INACTIVE);
 }
 
+int thread_exit(struct ktcb *task)
+{
+
+	return thread_signal(task, TASK_EXITING, TASK_DEAD);
+}
+
 static inline int TASK_IS_CHILD(struct ktcb *task)
 {
 	return (((task) != current) &&
@@ -62,7 +68,7 @@ static inline int TASK_IS_CHILD(struct ktcb *task)
 
 int thread_destroy_child(struct ktcb *task)
 {
-	thread_suspend(task);
+	thread_exit(task);
 
 	tcb_remove(task);
 
@@ -71,7 +77,7 @@ int thread_destroy_child(struct ktcb *task)
 	wake_up_all(&task->wqh_recv, WAKEUP_INTERRUPT);
 
 	BUG_ON(task->wqh_pager.sleepers > 0);
-	BUG_ON(task->state != TASK_INACTIVE);
+	BUG_ON(task->state != TASK_DEAD);
 
 	tcb_delete(task);
 	return 0;
@@ -100,7 +106,12 @@ void thread_destroy_self()
 {
 	thread_destroy_children();
 
-	sched_suspend_sync();
+	sched_exit_sync();
+}
+
+int thread_wait(struct ktcb *task)
+{
+	return 0;
 }
 
 int thread_destroy(struct ktcb *task)
@@ -177,6 +188,8 @@ int thread_start(struct ktcb *task)
 	if (!mutex_trylock(&task->thread_control_lock))
 		return -EAGAIN;
 
+	/* FIXME: Refuse to run dead tasks */
+
 	/* Notify scheduler of task resume */
 	sched_resume_async(task);
 
@@ -404,6 +417,9 @@ int sys_thread_control(unsigned int flags, struct task_ids *ids)
 	case THREAD_RECYCLE:
 		ret = thread_recycle(task);
 		break;
+	case THREAD_WAIT:
+		ret = thread_wait(task);
+		break;
 
 	default:
 		ret = -EINVAL;

src/arch/arm/exception.c

@@ -282,7 +282,11 @@ void data_abort_handler(u32 faulted_pc, u32 fsr, u32 far)
 	if (current->flags & TASK_SUSPENDING) {
 		BUG_ON(current->nlocks);
 		sched_suspend_sync();
+	} else if (current->flags & TASK_EXITING) {
+		BUG_ON(current->nlocks);
+		sched_exit_sync();
 	}
+
 	return;
 
 error:
@@ -311,7 +315,11 @@ void prefetch_abort_handler(u32 faulted_pc, u32 fsr, u32 far, u32 lr)
 	if (current->flags & TASK_SUSPENDING) {
 		BUG_ON(current->nlocks);
 		sched_suspend_sync();
+	} else if (current->flags & TASK_EXITING) {
+		BUG_ON(current->nlocks);
+		sched_exit_sync();
 	}
+
 	return;
 
 error:

src/generic/capability.c

@@ -437,6 +437,11 @@ struct capability *cap_match_thread(struct capability *cap,
 		if (!(cap->access & CAP_TCTRL_RECYCLE))
 			return 0;
 		break;
+	case THREAD_WAIT:
+		if (!(cap->access & CAP_TCTRL_WAIT))
+			return 0;
+		break;
+
 	default:
 		/* We refuse to accept anything else */
 		return 0;

src/generic/scheduler.c

@@ -225,6 +225,22 @@ void sched_resume_async(struct ktcb *task)
 			  RQ_ADD_FRONT);
 }
 
+
+/* Same as suspend, task state and flags are different */
+void sched_exit_sync(void)
+{
+	preempt_disable();
+	sched_rq_remove_task(current);
+	current->state = TASK_DEAD;
+	current->flags &= ~TASK_EXITING;
+	preempt_enable();
+
+	if (current->pagerid != current->tid)
+		wake_up(&current->wqh_pager, 0);
+
+	schedule();
+}
+
 /*
  * NOTE: Could do these as sched_prepare_suspend()
  * + schedule() or need_resched = 1

src/glue/arm/systable.c

@@ -170,6 +170,9 @@ int syscall(syscall_context_t *regs, unsigned long swi_addr)
 	if (current->flags & TASK_SUSPENDING) {
 		BUG_ON(current->nlocks);
 		sched_suspend_sync();
+	} else if (current->flags & TASK_EXITING) {
+		BUG_ON(current->nlocks);
+		sched_exit_sync();
 	}
 
 	return ret;