From 02a12be131abbf74f3df90b0673e363c9d35b1c1 Mon Sep 17 00:00:00 2001
From: Matthias Kruk <m@m10k.eu>
Date: Sun, 29 Sep 2019 14:53:38 +0900
Subject: [PATCH] Use task_switch() to switch tasks in sched_tick(), instead of
 task_set_current()

---
 kernel/core/sched.c | 42 ++++++++++++++++++++++++++++++++----------
 1 file changed, 32 insertions(+), 10 deletions(-)

diff --git a/kernel/core/sched.c b/kernel/core/sched.c
index 497d504..8fa6199 100644
--- a/kernel/core/sched.c
+++ b/kernel/core/sched.c
@@ -1,6 +1,7 @@
 #include <config.h>
 #include <corax/types.h>
 #include <corax/heap.h>
+#include <corax/errno.h>
 #include <debug.h>
 #include <arch.h>
 
@@ -10,7 +11,7 @@ struct task_queue {
 };
 
 /* FIXME: This should be per-processor */
-static struct task_queue *_readyq;
+static struct task_queue *_readyq = NULL;
 
 static void _nq(struct task_queue **q, task_t *t)
 {
@@ -20,13 +21,13 @@ static void _nq(struct task_queue **q, task_t *t)
 
 	if(item) {
 		item->data = t;
+		item->next = NULL;
 
 		/* get a pointer to the end of the queue */
 		while(*q) {
-			q = &((*q)->next);
+	    	q = &((*q)->next);
 		}
 
-		item->next = *q;
 		*q = item;
 	}
 
@@ -70,16 +71,37 @@ void sched_tick(void)
 
 		/* put the task back on the ready queue */
 	    _nq(&_readyq, cur_task);
+	}
 
-		/* get the next task from the ready queue */
-		cur_task = _dq(&_readyq);
+	/* get the next task from the ready queue */
+	cur_task = _dq(&_readyq);
 
-		if(cur_task) {
-			task_set_current(cur_task);
-		} else {
-			dbg_printf("This should not have happened\n");
-		}
+	if(cur_task) {
+		dbg_printf("Switch to task %p [%02x]\n", cur_task, cur_task->t_state);
+		task_switch(cur_task);
+		dbg_printf("Returned to task %p\n", task_get_current());
+	} else {
+		dbg_printf("This should not have happened\n");
 	}
 
 	return;
 }
+
+int sched_enqueue(task_t *t)
+{
+	int ret_val;
+
+	ret_val = -EINVAL;
+
+	/*
+	 * Don't allow tasks to be enqueued unless they are in
+	 * state TASK_STATE_NEW
+	 */
+
+	if(t->t_state == TASK_STATE_NEW) {
+		_nq(&_readyq, t);
+		ret_val = 0;
+	}
+
+	return(ret_val);
+}
-- 
2.47.3