v4.19.13 snapshot.
diff --git a/drivers/cpuidle/poll_state.c b/drivers/cpuidle/poll_state.c
new file mode 100644
index 0000000..3f86d23
--- /dev/null
+++ b/drivers/cpuidle/poll_state.c
@@ -0,0 +1,52 @@
+/*
+ * poll_state.c - Polling idle state
+ *
+ * This file is released under the GPLv2.
+ */
+
+#include <linux/cpuidle.h>
+#include <linux/sched.h>
+#include <linux/sched/clock.h>
+#include <linux/sched/idle.h>
+
+#define POLL_IDLE_TIME_LIMIT (TICK_NSEC / 16)
+#define POLL_IDLE_RELAX_COUNT 200
+
+static int __cpuidle poll_idle(struct cpuidle_device *dev,
+ struct cpuidle_driver *drv, int index)
+{
+ u64 time_start = local_clock();
+
+ local_irq_enable();
+ if (!current_set_polling_and_test()) {
+ unsigned int loop_count = 0;
+
+ while (!need_resched()) {
+ cpu_relax();
+ if (loop_count++ < POLL_IDLE_RELAX_COUNT)
+ continue;
+
+ loop_count = 0;
+ if (local_clock() - time_start > POLL_IDLE_TIME_LIMIT)
+ break;
+ }
+ }
+ current_clr_polling();
+
+ return index;
+}
+
+void cpuidle_poll_state_init(struct cpuidle_driver *drv)
+{
+ struct cpuidle_state *state = &drv->states[0];
+
+ snprintf(state->name, CPUIDLE_NAME_LEN, "POLL");
+ snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE");
+ state->exit_latency = 0;
+ state->target_residency = 0;
+ state->power_usage = -1;
+ state->enter = poll_idle;
+ state->disabled = false;
+ state->flags = CPUIDLE_FLAG_POLLING;
+}
+EXPORT_SYMBOL_GPL(cpuidle_poll_state_init);