1 files changed, 229 insertions, 0 deletions
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
new file mode 100644
index 000000000..8806444a6
--- /dev/null
+++ b/kernel/irq/handle.c
@@ -0,0 +1,229 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
+ * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
+ *
+ * This file contains the core interrupt handling code. Detailed
+ * information is available in Documentation/core-api/genericirq.rst
+ *
+ */
+
+#include <linux/irq.h>
+#include <linux/random.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/kernel_stat.h>
+
+#include <trace/events/irq.h>
+
+#include "internals.h"
+
+#ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER
+void (*handle_arch_irq)(struct pt_regs *) __ro_after_init;
+#endif
+
+/**
+ * handle_bad_irq - handle spurious and unhandled irqs
+ * @desc:      description of the interrupt
+ *
+ * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
+ */
+void handle_bad_irq(struct irq_desc *desc)
+{
+	unsigned int irq = irq_desc_get_irq(desc);
+
+	print_irq_desc(irq, desc);
+	kstat_incr_irqs_this_cpu(desc);
+	ack_bad_irq(irq);
+}
+EXPORT_SYMBOL_GPL(handle_bad_irq);
+
+/*
+ * Special, empty irq handler:
+ */
+irqreturn_t no_action(int cpl, void *dev_id)
+{
+	return IRQ_NONE;
+}
+EXPORT_SYMBOL_GPL(no_action);
+
+static void warn_no_thread(unsigned int irq, struct irqaction *action)
+{
+	if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags))
+		return;
+
+	printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD "
+	       "but no thread function available.", irq, action->name);
+}
+
+void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action)
+{
+	/*
+	 * In case the thread crashed and was killed we just pretend that
+	 * we handled the interrupt. The hardirq handler has disabled the
+	 * device interrupt, so no irq storm is lurking.
+	 */
+	if (action->thread->flags & PF_EXITING)
+		return;
+
+	/*
+	 * Wake up the handler thread for this action. If the
+	 * RUNTHREAD bit is already set, nothing to do.
+	 */
+	if (test_and_set_bit(IRQTF_RUNTHREAD, &action->thread_flags))
+		return;
+
+	/*
+	 * It's safe to OR the mask lockless here. We have only two
+	 * places which write to threads_oneshot: This code and the
+	 * irq thread.
+	 *
+	 * This code is the hard irq context and can never run on two
+	 * cpus in parallel. If it ever does we have more serious
+	 * problems than this bitmask.
+	 *
+	 * The irq threads of this irq which clear their "running" bit
+	 * in threads_oneshot are serialized via desc->lock against
+	 * each other and they are serialized against this code by
+	 * IRQS_INPROGRESS.
+	 *
+	 * Hard irq handler:
+	 *
+	 *	spin_lock(desc->lock);
+	 *	desc->state |= IRQS_INPROGRESS;
+	 *	spin_unlock(desc->lock);
+	 *	set_bit(IRQTF_RUNTHREAD, &action->thread_flags);
+	 *	desc->threads_oneshot |= mask;
+	 *	spin_lock(desc->lock);
+	 *	desc->state &= ~IRQS_INPROGRESS;
+	 *	spin_unlock(desc->lock);
+	 *
+	 * irq thread:
+	 *
+	 * again:
+	 *	spin_lock(desc->lock);
+	 *	if (desc->state & IRQS_INPROGRESS) {
+	 *		spin_unlock(desc->lock);
+	 *		while(desc->state & IRQS_INPROGRESS)
+	 *			cpu_relax();
+	 *		goto again;
+	 *	}
+	 *	if (!test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
+	 *		desc->threads_oneshot &= ~mask;
+	 *	spin_unlock(desc->lock);
+	 *
+	 * So either the thread waits for us to clear IRQS_INPROGRESS
+	 * or we are waiting in the flow handler for desc->lock to be
+	 * released before we reach this point. The thread also checks
+	 * IRQTF_RUNTHREAD under desc->lock. If set it leaves
+	 * threads_oneshot untouched and runs the thread another time.
+	 */
+	desc->threads_oneshot |= action->thread_mask;
+
+	/*
+	 * We increment the threads_active counter in case we wake up
+	 * the irq thread. The irq thread decrements the counter when
+	 * it returns from the handler or in the exit path and wakes
+	 * up waiters which are stuck in synchronize_irq() when the
+	 * active count becomes zero. synchronize_irq() is serialized
+	 * against this code (hard irq handler) via IRQS_INPROGRESS
+	 * like the finalize_oneshot() code. See comment above.
+	 */
+	atomic_inc(&desc->threads_active);
+
+	wake_up_process(action->thread);
+}
+
+irqreturn_t __handle_irq_event_percpu(struct irq_desc *desc, unsigned int *flags)
+{
+	irqreturn_t retval = IRQ_NONE;
+	unsigned int irq = desc->irq_data.irq;
+	struct irqaction *action;
+
+	record_irq_time(desc);
+
+	for_each_action_of_desc(desc, action) {
+		irqreturn_t res;
+
+		/*
+		 * If this IRQ would be threaded under force_irqthreads, mark it so.
+		 */
+		if (irq_settings_can_thread(desc) &&
+		    !(action->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT)))
+			lockdep_hardirq_threaded();
+
+		trace_irq_handler_entry(irq, action);
+		res = action->handler(irq, action->dev_id);
+		trace_irq_handler_exit(irq, action, res);
+
+		if (WARN_ONCE(!irqs_disabled(),"irq %u handler %pS enabled interrupts\n",
+			      irq, action->handler))
+			local_irq_disable();
+
+		switch (res) {
+		case IRQ_WAKE_THREAD:
+			/*
+			 * Catch drivers which return WAKE_THREAD but
+			 * did not set up a thread function
+			 */
+			if (unlikely(!action->thread_fn)) {
+				warn_no_thread(irq, action);
+				break;
+			}
+
+			__irq_wake_thread(desc, action);
+
+			fallthrough;	/* to add to randomness */
+		case IRQ_HANDLED:
+			*flags |= action->flags;
+			break;
+
+		default:
+			break;
+		}
+
+		retval |= res;
+	}
+
+	return retval;
+}
+
+irqreturn_t handle_irq_event_percpu(struct irq_desc *desc)
+{
+	irqreturn_t retval;
+	unsigned int flags = 0;
+
+	retval = __handle_irq_event_percpu(desc, &flags);
+
+	add_interrupt_randomness(desc->irq_data.irq);
+
+	if (!noirqdebug)
+		note_interrupt(desc, retval);
+	return retval;
+}
+
+irqreturn_t handle_irq_event(struct irq_desc *desc)
+{
+	irqreturn_t ret;
+
+	desc->istate &= ~IRQS_PENDING;
+	irqd_set(&desc->irq_data, IRQD_IRQ_INPROGRESS);
+	raw_spin_unlock(&desc->lock);
+
+	ret = handle_irq_event_percpu(desc);
+
+	raw_spin_lock(&desc->lock);
+	irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
+	return ret;
+}
+
+#ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER
+int __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
+{
+	if (handle_arch_irq)
+		return -EBUSY;
+
+	handle_arch_irq = handle_irq;
+	return 0;
+}
+#endif