1 files changed, 300 insertions, 0 deletions
diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c
new file mode 100644
index 0000000..dd364c1
--- /dev/null
+++ b/kernel/irq/spurious.c
@@ -0,0 +1,300 @@
+/*
+ * linux/kernel/irq/spurious.c
+ *
+ * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
+ *
+ * This file contains spurious interrupt handling.
+ */
+
+#include <linux/jiffies.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+#include <linux/interrupt.h>
+#include <linux/moduleparam.h>
+#include <linux/timer.h>
+
+static int irqfixup __read_mostly;
+
+#define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10)
+static void poll_spurious_irqs(unsigned long dummy);
+static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs, 0, 0);
+
+/*
+ * Recovery handler for misrouted interrupts.
+ */
+static int try_one_irq(int irq, struct irq_desc *desc)
+{
+	struct irqaction *action;
+	int ok = 0, work = 0;
+
+	spin_lock(&desc->lock);
+	/* Already running on another processor */
+	if (desc->status & IRQ_INPROGRESS) {
+		/*
+		 * Already running: If it is shared get the other
+		 * CPU to go looking for our mystery interrupt too
+		 */
+		if (desc->action && (desc->action->flags & IRQF_SHARED))
+			desc->status |= IRQ_PENDING;
+		spin_unlock(&desc->lock);
+		return ok;
+	}
+	/* Honour the normal IRQ locking */
+	desc->status |= IRQ_INPROGRESS;
+	action = desc->action;
+	spin_unlock(&desc->lock);
+
+	while (action) {
+		/* Only shared IRQ handlers are safe to call */
+		if (action->flags & IRQF_SHARED) {
+			if (action->handler(irq, action->dev_id) ==
+				IRQ_HANDLED)
+				ok = 1;
+		}
+		action = action->next;
+	}
+	local_irq_disable();
+	/* Now clean up the flags */
+	spin_lock(&desc->lock);
+	action = desc->action;
+
+	/*
+	 * While we were looking for a fixup someone queued a real
+	 * IRQ clashing with our walk:
+	 */
+	while ((desc->status & IRQ_PENDING) && action) {
+		/*
+		 * Perform real IRQ processing for the IRQ we deferred
+		 */
+		work = 1;
+		spin_unlock(&desc->lock);
+		handle_IRQ_event(irq, action);
+		spin_lock(&desc->lock);
+		desc->status &= ~IRQ_PENDING;
+	}
+	desc->status &= ~IRQ_INPROGRESS;
+	/*
+	 * If we did actual work for the real IRQ line we must let the
+	 * IRQ controller clean up too
+	 */
+	if (work && desc->chip && desc->chip->end)
+		desc->chip->end(irq);
+	spin_unlock(&desc->lock);
+
+	return ok;
+}
+
+static int misrouted_irq(int irq)
+{
+	struct irq_desc *desc;
+	int i, ok = 0;
+
+	for_each_irq_desc(i, desc) {
+		if (!i)
+			 continue;
+
+		if (i == irq)	/* Already tried */
+			continue;
+
+		if (try_one_irq(i, desc))
+			ok = 1;
+	}
+	/* So the caller can adjust the irq error counts */
+	return ok;
+}
+
+static void poll_spurious_irqs(unsigned long dummy)
+{
+	struct irq_desc *desc;
+	int i;
+
+	for_each_irq_desc(i, desc) {
+		unsigned int status;
+
+		if (!i)
+			 continue;
+
+		/* Racy but it doesn't matter */
+		status = desc->status;
+		barrier();
+		if (!(status & IRQ_SPURIOUS_DISABLED))
+			continue;
+
+		try_one_irq(i, desc);
+	}
+
+	mod_timer(&poll_spurious_irq_timer,
+		  jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
+}
+
+/*
+ * If 99,900 of the previous 100,000 interrupts have not been handled
+ * then assume that the IRQ is stuck in some manner. Drop a diagnostic
+ * and try to turn the IRQ off.
+ *
+ * (The other 100-of-100,000 interrupts may have been a correctly
+ *  functioning device sharing an IRQ with the failing one)
+ *
+ * Called under desc->lock
+ */
+
+static void
+__report_bad_irq(unsigned int irq, struct irq_desc *desc,
+		 irqreturn_t action_ret)
+{
+	struct irqaction *action;
+
+	if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
+		printk(KERN_ERR "irq event %d: bogus return value %x\n",
+				irq, action_ret);
+	} else {
+		printk(KERN_ERR "irq %d: nobody cared (try booting with "
+				"the \"irqpoll\" option)\n", irq);
+	}
+	dump_stack();
+	printk(KERN_ERR "handlers:\n");
+
+	action = desc->action;
+	while (action) {
+		printk(KERN_ERR "[<%p>]", action->handler);
+		print_symbol(" (%s)",
+			(unsigned long)action->handler);
+		printk("\n");
+		action = action->next;
+	}
+}
+
+static void
+report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
+{
+	static int count = 100;
+
+	if (count > 0) {
+		count--;
+		__report_bad_irq(irq, desc, action_ret);
+	}
+}
+
+static inline int
+try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
+		  irqreturn_t action_ret)
+{
+	struct irqaction *action;
+
+	if (!irqfixup)
+		return 0;
+
+	/* We didn't actually handle the IRQ - see if it was misrouted? */
+	if (action_ret == IRQ_NONE)
+		return 1;
+
+	/*
+	 * But for 'irqfixup == 2' we also do it for handled interrupts if
+	 * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
+	 * traditional PC timer interrupt.. Legacy)
+	 */
+	if (irqfixup < 2)
+		return 0;
+
+	if (!irq)
+		return 1;
+
+	/*
+	 * Since we don't get the descriptor lock, "action" can
+	 * change under us.  We don't really care, but we don't
+	 * want to follow a NULL pointer. So tell the compiler to
+	 * just load it once by using a barrier.
+	 */
+	action = desc->action;
+	barrier();
+	return action && (action->flags & IRQF_IRQPOLL);
+}
+
+void note_interrupt(unsigned int irq, struct irq_desc *desc,
+		    irqreturn_t action_ret)
+{
+	if (unlikely(action_ret != IRQ_HANDLED)) {
+		/*
+		 * If we are seeing only the odd spurious IRQ caused by
+		 * bus asynchronicity then don't eventually trigger an error,
+		 * otherwise the couter becomes a doomsday timer for otherwise
+		 * working systems
+		 */
+		if (time_after(jiffies, desc->last_unhandled + HZ/10))
+			desc->irqs_unhandled = 1;
+		else
+			desc->irqs_unhandled++;
+		desc->last_unhandled = jiffies;
+		if (unlikely(action_ret != IRQ_NONE))
+			report_bad_irq(irq, desc, action_ret);
+	}
+
+	if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
+		int ok = misrouted_irq(irq);
+		if (action_ret == IRQ_NONE)
+			desc->irqs_unhandled -= ok;
+	}
+
+	desc->irq_count++;
+	if (likely(desc->irq_count < 100000))
+		return;
+
+	desc->irq_count = 0;
+	if (unlikely(desc->irqs_unhandled > 99900)) {
+		/*
+		 * The interrupt is stuck
+		 */
+		__report_bad_irq(irq, desc, action_ret);
+		/*
+		 * Now kill the IRQ
+		 */
+		printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
+		desc->status |= IRQ_DISABLED | IRQ_SPURIOUS_DISABLED;
+		desc->depth++;
+		desc->chip->disable(irq);
+
+		mod_timer(&poll_spurious_irq_timer,
+			  jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
+	}
+	desc->irqs_unhandled = 0;
+}
+
+int noirqdebug __read_mostly;
+
+int noirqdebug_setup(char *str)
+{
+	noirqdebug = 1;
+	printk(KERN_INFO "IRQ lockup detection disabled\n");
+
+	return 1;
+}
+
+__setup("noirqdebug", noirqdebug_setup);
+module_param(noirqdebug, bool, 0644);
+MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
+
+static int __init irqfixup_setup(char *str)
+{
+	irqfixup = 1;
+	printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
+	printk(KERN_WARNING "This may impact system performance.\n");
+
+	return 1;
+}
+
+__setup("irqfixup", irqfixup_setup);
+module_param(irqfixup, int, 0644);
+MODULE_PARM_DESC("irqfixup", "0: No fixup, 1: irqfixup mode, 2: irqpoll mode");
+
+static int __init irqpoll_setup(char *str)
+{
+	irqfixup = 2;
+	printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
+				"enabled\n");
+	printk(KERN_WARNING "This may significantly impact system "
+				"performance\n");
+	return 1;
+}
+
+__setup("irqpoll", irqpoll_setup);