1 files changed, 277 insertions, 0 deletions
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
new file mode 100644
index 0000000..c815b42
--- /dev/null
+++ b/kernel/irq/handle.c
@@ -0,0 +1,277 @@
+/*
+ * linux/kernel/irq/handle.c
+ *
+ * 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/DocBook/genericirq
+ *
+ */
+
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/interrupt.h>
+#include <linux/kernel_stat.h>
+
+#include "internals.h"
+
+/**
+ * handle_bad_irq - handle spurious and unhandled irqs
+ * @irq:       the interrupt number
+ * @desc:      description of the interrupt
+ *
+ * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
+ */
+void handle_bad_irq(unsigned int irq, struct irq_desc *desc)
+{
+	print_irq_desc(irq, desc);
+	kstat_incr_irqs_this_cpu(irq, desc);
+	ack_bad_irq(irq);
+}
+
+/*
+ * Linux has a controller-independent interrupt architecture.
+ * Every controller has a 'controller-template', that is used
+ * by the main code to do the right thing. Each driver-visible
+ * interrupt source is transparently wired to the appropriate
+ * controller. Thus drivers need not be aware of the
+ * interrupt-controller.
+ *
+ * The code is designed to be easily extended with new/different
+ * interrupt controllers, without having to do assembly magic or
+ * having to touch the generic code.
+ *
+ * Controller mappings for all interrupt sources:
+ */
+int nr_irqs = NR_IRQS;
+EXPORT_SYMBOL_GPL(nr_irqs);
+
+struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
+	[0 ... NR_IRQS-1] = {
+		.status = IRQ_DISABLED,
+		.chip = &no_irq_chip,
+		.handle_irq = handle_bad_irq,
+		.depth = 1,
+		.lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
+#ifdef CONFIG_SMP
+		.affinity = CPU_MASK_ALL
+#endif
+	}
+};
+
+/*
+ * What should we do if we get a hw irq event on an illegal vector?
+ * Each architecture has to answer this themself.
+ */
+static void ack_bad(unsigned int irq)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+
+	print_irq_desc(irq, desc);
+	ack_bad_irq(irq);
+}
+
+/*
+ * NOP functions
+ */
+static void noop(unsigned int irq)
+{
+}
+
+static unsigned int noop_ret(unsigned int irq)
+{
+	return 0;
+}
+
+/*
+ * Generic no controller implementation
+ */
+struct irq_chip no_irq_chip = {
+	.name		= "none",
+	.startup	= noop_ret,
+	.shutdown	= noop,
+	.enable		= noop,
+	.disable	= noop,
+	.ack		= ack_bad,
+	.end		= noop,
+};
+
+/*
+ * Generic dummy implementation which can be used for
+ * real dumb interrupt sources
+ */
+struct irq_chip dummy_irq_chip = {
+	.name		= "dummy",
+	.startup	= noop_ret,
+	.shutdown	= noop,
+	.enable		= noop,
+	.disable	= noop,
+	.ack		= noop,
+	.mask		= noop,
+	.unmask		= noop,
+	.end		= noop,
+};
+
+/*
+ * Special, empty irq handler:
+ */
+irqreturn_t no_action(int cpl, void *dev_id)
+{
+	return IRQ_NONE;
+}
+
+/**
+ * handle_IRQ_event - irq action chain handler
+ * @irq:	the interrupt number
+ * @action:	the interrupt action chain for this irq
+ *
+ * Handles the action chain of an irq event
+ */
+irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
+{
+	irqreturn_t ret, retval = IRQ_NONE;
+	unsigned int status = 0;
+
+	if (!(action->flags & IRQF_DISABLED))
+		local_irq_enable_in_hardirq();
+
+	do {
+		ret = action->handler(irq, action->dev_id);
+		if (ret == IRQ_HANDLED)
+			status |= action->flags;
+		retval |= ret;
+		action = action->next;
+	} while (action);
+
+	if (status & IRQF_SAMPLE_RANDOM)
+		add_interrupt_randomness(irq);
+	local_irq_disable();
+
+	return retval;
+}
+
+#ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
+/**
+ * __do_IRQ - original all in one highlevel IRQ handler
+ * @irq:	the interrupt number
+ *
+ * __do_IRQ handles all normal device IRQ's (the special
+ * SMP cross-CPU interrupts have their own specific
+ * handlers).
+ *
+ * This is the original x86 implementation which is used for every
+ * interrupt type.
+ */
+unsigned int __do_IRQ(unsigned int irq)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+	struct irqaction *action;
+	unsigned int status;
+
+	kstat_incr_irqs_this_cpu(irq, desc);
+
+	if (CHECK_IRQ_PER_CPU(desc->status)) {
+		irqreturn_t action_ret;
+
+		/*
+		 * No locking required for CPU-local interrupts:
+		 */
+		if (desc->chip->ack)
+			desc->chip->ack(irq);
+		if (likely(!(desc->status & IRQ_DISABLED))) {
+			action_ret = handle_IRQ_event(irq, desc->action);
+			if (!noirqdebug)
+				note_interrupt(irq, desc, action_ret);
+		}
+		desc->chip->end(irq);
+		return 1;
+	}
+
+	spin_lock(&desc->lock);
+	if (desc->chip->ack)
+		desc->chip->ack(irq);
+	/*
+	 * REPLAY is when Linux resends an IRQ that was dropped earlier
+	 * WAITING is used by probe to mark irqs that are being tested
+	 */
+	status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
+	status |= IRQ_PENDING; /* we _want_ to handle it */
+
+	/*
+	 * If the IRQ is disabled for whatever reason, we cannot
+	 * use the action we have.
+	 */
+	action = NULL;
+	if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
+		action = desc->action;
+		status &= ~IRQ_PENDING; /* we commit to handling */
+		status |= IRQ_INPROGRESS; /* we are handling it */
+	}
+	desc->status = status;
+
+	/*
+	 * If there is no IRQ handler or it was disabled, exit early.
+	 * Since we set PENDING, if another processor is handling
+	 * a different instance of this same irq, the other processor
+	 * will take care of it.
+	 */
+	if (unlikely(!action))
+		goto out;
+
+	/*
+	 * Edge triggered interrupts need to remember
+	 * pending events.
+	 * This applies to any hw interrupts that allow a second
+	 * instance of the same irq to arrive while we are in do_IRQ
+	 * or in the handler. But the code here only handles the _second_
+	 * instance of the irq, not the third or fourth. So it is mostly
+	 * useful for irq hardware that does not mask cleanly in an
+	 * SMP environment.
+	 */
+	for (;;) {
+		irqreturn_t action_ret;
+
+		spin_unlock(&desc->lock);
+
+		action_ret = handle_IRQ_event(irq, action);
+		if (!noirqdebug)
+			note_interrupt(irq, desc, action_ret);
+
+		spin_lock(&desc->lock);
+		if (likely(!(desc->status & IRQ_PENDING)))
+			break;
+		desc->status &= ~IRQ_PENDING;
+	}
+	desc->status &= ~IRQ_INPROGRESS;
+
+out:
+	/*
+	 * The ->end() handler has to deal with interrupts which got
+	 * disabled while the handler was running.
+	 */
+	desc->chip->end(irq);
+	spin_unlock(&desc->lock);
+
+	return 1;
+}
+#endif
+
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+/*
+ * lockdep: we want to handle all irq_desc locks as a single lock-class:
+ */
+static struct lock_class_key irq_desc_lock_class;
+
+void early_init_irq_lock_class(void)
+{
+	struct irq_desc *desc;
+	int i;
+
+	for_each_irq_desc(i, desc)
+		lockdep_set_class(&desc->lock, &irq_desc_lock_class);
+}
+#endif