1 files changed, 86 insertions, 0 deletions
diff --git a/include/linux/sched/idle.h b/include/linux/sched/idle.h
new file mode 100644
index 000000000000..5ca63ebad6b4
--- /dev/null
+++ b/include/linux/sched/idle.h
@@ -0,0 +1,86 @@
+#ifndef _LINUX_SCHED_IDLE_H
+#define _LINUX_SCHED_IDLE_H
+
+#include <linux/sched.h>
+
+enum cpu_idle_type {
+	CPU_IDLE,
+	CPU_NOT_IDLE,
+	CPU_NEWLY_IDLE,
+	CPU_MAX_IDLE_TYPES
+};
+
+extern void wake_up_if_idle(int cpu);
+
+/*
+ * Idle thread specific functions to determine the need_resched
+ * polling state.
+ */
+#ifdef TIF_POLLING_NRFLAG
+
+static inline void __current_set_polling(void)
+{
+	set_thread_flag(TIF_POLLING_NRFLAG);
+}
+
+static inline bool __must_check current_set_polling_and_test(void)
+{
+	__current_set_polling();
+
+	/*
+	 * Polling state must be visible before we test NEED_RESCHED,
+	 * paired by resched_curr()
+	 */
+	smp_mb__after_atomic();
+
+	return unlikely(tif_need_resched());
+}
+
+static inline void __current_clr_polling(void)
+{
+	clear_thread_flag(TIF_POLLING_NRFLAG);
+}
+
+static inline bool __must_check current_clr_polling_and_test(void)
+{
+	__current_clr_polling();
+
+	/*
+	 * Polling state must be visible before we test NEED_RESCHED,
+	 * paired by resched_curr()
+	 */
+	smp_mb__after_atomic();
+
+	return unlikely(tif_need_resched());
+}
+
+#else
+static inline void __current_set_polling(void) { }
+static inline void __current_clr_polling(void) { }
+
+static inline bool __must_check current_set_polling_and_test(void)
+{
+	return unlikely(tif_need_resched());
+}
+static inline bool __must_check current_clr_polling_and_test(void)
+{
+	return unlikely(tif_need_resched());
+}
+#endif
+
+static inline void current_clr_polling(void)
+{
+	__current_clr_polling();
+
+	/*
+	 * Ensure we check TIF_NEED_RESCHED after we clear the polling bit.
+	 * Once the bit is cleared, we'll get IPIs with every new
+	 * TIF_NEED_RESCHED and the IPI handler, scheduler_ipi(), will also
+	 * fold.
+	 */
+	smp_mb(); /* paired with resched_curr() */
+
+	preempt_fold_need_resched();
+}
+
+#endif /* _LINUX_SCHED_IDLE_H */