zte's code,first commit
Change-Id: I9a04da59e459a9bc0d67f101f700d9d7dc8d681b
diff --git a/ap/os/linux/linux-3.4.x/kernel/sched/stop_task.c b/ap/os/linux/linux-3.4.x/kernel/sched/stop_task.c
new file mode 100644
index 0000000..da5eb5b
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/kernel/sched/stop_task.c
@@ -0,0 +1,128 @@
+#include "sched.h"
+
+/*
+ * stop-task scheduling class.
+ *
+ * The stop task is the highest priority task in the system, it preempts
+ * everything and will be preempted by nothing.
+ *
+ * See kernel/stop_machine.c
+ */
+
+#ifdef CONFIG_SMP
+static int
+select_task_rq_stop(struct task_struct *p, int sd_flag, int flags)
+{
+ return task_cpu(p); /* stop tasks as never migrate */
+}
+#endif /* CONFIG_SMP */
+
+static void
+check_preempt_curr_stop(struct rq *rq, struct task_struct *p, int flags)
+{
+ /* we're never preempted */
+}
+
+static struct task_struct *pick_next_task_stop(struct rq *rq)
+{
+ struct task_struct *stop = rq->stop;
+
+ if (stop && stop->on_rq) {
+ stop->se.exec_start = rq->clock_task;
+ return stop;
+ }
+
+ return NULL;
+}
+
+static void
+enqueue_task_stop(struct rq *rq, struct task_struct *p, int flags)
+{
+ inc_nr_running(rq);
+}
+
+static void
+dequeue_task_stop(struct rq *rq, struct task_struct *p, int flags)
+{
+ dec_nr_running(rq);
+}
+
+static void yield_task_stop(struct rq *rq)
+{
+ BUG(); /* the stop task should never yield, its pointless. */
+}
+
+static void put_prev_task_stop(struct rq *rq, struct task_struct *prev)
+{
+ struct task_struct *curr = rq->curr;
+ u64 delta_exec;
+
+ delta_exec = rq->clock_task - curr->se.exec_start;
+ if (unlikely((s64)delta_exec < 0))
+ delta_exec = 0;
+
+ schedstat_set(curr->se.statistics.exec_max,
+ max(curr->se.statistics.exec_max, delta_exec));
+
+ curr->se.sum_exec_runtime += delta_exec;
+ account_group_exec_runtime(curr, delta_exec);
+
+ curr->se.exec_start = rq->clock_task;
+ cpuacct_charge(curr, delta_exec);
+}
+
+static void task_tick_stop(struct rq *rq, struct task_struct *curr, int queued)
+{
+}
+
+static void set_curr_task_stop(struct rq *rq)
+{
+ struct task_struct *stop = rq->stop;
+
+ stop->se.exec_start = rq->clock_task;
+}
+
+static void switched_to_stop(struct rq *rq, struct task_struct *p)
+{
+ BUG(); /* its impossible to change to this class */
+}
+
+static void
+prio_changed_stop(struct rq *rq, struct task_struct *p, int oldprio)
+{
+ BUG(); /* how!?, what priority? */
+}
+
+static unsigned int
+get_rr_interval_stop(struct rq *rq, struct task_struct *task)
+{
+ return 0;
+}
+
+/*
+ * Simple, special scheduling class for the per-CPU stop tasks:
+ */
+const struct sched_class stop_sched_class = {
+ .next = &rt_sched_class,
+
+ .enqueue_task = enqueue_task_stop,
+ .dequeue_task = dequeue_task_stop,
+ .yield_task = yield_task_stop,
+
+ .check_preempt_curr = check_preempt_curr_stop,
+
+ .pick_next_task = pick_next_task_stop,
+ .put_prev_task = put_prev_task_stop,
+
+#ifdef CONFIG_SMP
+ .select_task_rq = select_task_rq_stop,
+#endif
+
+ .set_curr_task = set_curr_task_stop,
+ .task_tick = task_tick_stop,
+
+ .get_rr_interval = get_rr_interval_stop,
+
+ .prio_changed = prio_changed_stop,
+ .switched_to = switched_to_stop,
+};