v4.19.13 snapshot.
diff --git a/kernel/irq/resend.c b/kernel/irq/resend.c
new file mode 100644
index 0000000..95414ad
--- /dev/null
+++ b/kernel/irq/resend.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
+ * Copyright (C) 2005-2006, Thomas Gleixner
+ *
+ * This file contains the IRQ-resend code
+ *
+ * If the interrupt is waiting to be processed, we try to re-run it.
+ * We can't directly run it from here since the caller might be in an
+ * interrupt-protected region. Not all irq controller chips can
+ * retrigger interrupts at the hardware level, so in those cases
+ * we allow the resending of IRQs via a tasklet.
+ */
+
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/interrupt.h>
+
+#include "internals.h"
+
+#ifdef CONFIG_HARDIRQS_SW_RESEND
+
+/* Bitmap to handle software resend of interrupts: */
+static DECLARE_BITMAP(irqs_resend, IRQ_BITMAP_BITS);
+
+/*
+ * Run software resends of IRQ's
+ */
+static void resend_irqs(unsigned long arg)
+{
+ struct irq_desc *desc;
+ int irq;
+
+ while (!bitmap_empty(irqs_resend, nr_irqs)) {
+ irq = find_first_bit(irqs_resend, nr_irqs);
+ clear_bit(irq, irqs_resend);
+ desc = irq_to_desc(irq);
+ local_irq_disable();
+ desc->handle_irq(desc);
+ local_irq_enable();
+ }
+}
+
+/* Tasklet to handle resend: */
+static DECLARE_TASKLET(resend_tasklet, resend_irqs, 0);
+
+#endif
+
+/*
+ * IRQ resend
+ *
+ * Is called with interrupts disabled and desc->lock held.
+ */
+void check_irq_resend(struct irq_desc *desc)
+{
+ /*
+ * We do not resend level type interrupts. Level type
+ * interrupts are resent by hardware when they are still
+ * active. Clear the pending bit so suspend/resume does not
+ * get confused.
+ */
+ if (irq_settings_is_level(desc)) {
+ desc->istate &= ~IRQS_PENDING;
+ return;
+ }
+ if (desc->istate & IRQS_REPLAY)
+ return;
+ if (desc->istate & IRQS_PENDING) {
+ desc->istate &= ~IRQS_PENDING;
+ desc->istate |= IRQS_REPLAY;
+
+ if (!desc->irq_data.chip->irq_retrigger ||
+ !desc->irq_data.chip->irq_retrigger(&desc->irq_data)) {
+#ifdef CONFIG_HARDIRQS_SW_RESEND
+ unsigned int irq = irq_desc_get_irq(desc);
+
+ /*
+ * If the interrupt is running in the thread
+ * context of the parent irq we need to be
+ * careful, because we cannot trigger it
+ * directly.
+ */
+ if (irq_settings_is_nested_thread(desc)) {
+ /*
+ * If the parent_irq is valid, we
+ * retrigger the parent, otherwise we
+ * do nothing.
+ */
+ if (!desc->parent_irq)
+ return;
+ irq = desc->parent_irq;
+ }
+ /* Set it pending and activate the softirq: */
+ set_bit(irq, irqs_resend);
+ tasklet_schedule(&resend_tasklet);
+#endif
+ }
+ }
+}