--- /dev/null
+/*
+ * 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>
+
+#include "internals.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);
+static int irq_poll_cpu;
+static atomic_t irq_poll_active;
+
+/*
+ * We wait here for a poller to finish.
+ *
+ * If the poll runs on this CPU, then we yell loudly and return
+ * false. That will leave the interrupt line disabled in the worst
+ * case, but it should never happen.
+ *
+ * We wait until the poller is done and then recheck disabled and
+ * action (about to be disabled). Only if it's still active, we return
+ * true and let the handler run.
+ */
+bool irq_wait_for_poll(struct irq_desc *desc)
+{
+ if (WARN_ONCE(irq_poll_cpu == smp_processor_id(),
+ "irq poll in progress on cpu %d for irq %d\n",
+ smp_processor_id(), desc->irq_data.irq))
+ return false;
+
+#ifdef CONFIG_SMP
+ do {
+ raw_spin_unlock(&desc->lock);
+ while (irqd_irq_inprogress(&desc->irq_data))
+ cpu_relax();
+ raw_spin_lock(&desc->lock);
+ } while (irqd_irq_inprogress(&desc->irq_data));
+ /* Might have been disabled in meantime */
+ return !irqd_irq_disabled(&desc->irq_data) && desc->action;
+#else
+ return false;
+#endif
+}
+
+
+/*
+ * Recovery handler for misrouted interrupts.
+ */
+static int try_one_irq(int irq, struct irq_desc *desc, bool force)
+{
+ irqreturn_t ret = IRQ_NONE;
+ struct irqaction *action;
+
+ raw_spin_lock(&desc->lock);
+
+ /*
+ * PER_CPU, nested thread interrupts and interrupts explicitely
+ * marked polled are excluded from polling.
+ */
+ if (irq_settings_is_per_cpu(desc) ||
+ irq_settings_is_nested_thread(desc) ||
+ irq_settings_is_polled(desc))
+ goto out;
+
+ /*
+ * Do not poll disabled interrupts unless the spurious
+ * disabled poller asks explicitely.
+ */
+ if (irqd_irq_disabled(&desc->irq_data) && !force)
+ goto out;
+
+ /*
+ * All handlers must agree on IRQF_SHARED, so we test just the
+ * first.
+ */
+ action = desc->action;
+ if (!action || !(action->flags & IRQF_SHARED) ||
+ (action->flags & __IRQF_TIMER))
+ goto out;
+
+ /* Already running on another processor */
+ if (irqd_irq_inprogress(&desc->irq_data)) {
+ /*
+ * Already running: If it is shared get the other
+ * CPU to go looking for our mystery interrupt too
+ */
+ desc->istate |= IRQS_PENDING;
+ goto out;
+ }
+
+ /* Mark it poll in progress */
+ desc->istate |= IRQS_POLL_INPROGRESS;
+ do {
+ if (handle_irq_event(desc) == IRQ_HANDLED)
+ ret = IRQ_HANDLED;
+ /* Make sure that there is still a valid action */
+ action = desc->action;
+ } while ((desc->istate & IRQS_PENDING) && action);
+ desc->istate &= ~IRQS_POLL_INPROGRESS;
+out:
+ raw_spin_unlock(&desc->lock);
+ return ret == IRQ_HANDLED;
+}
+
+static int misrouted_irq(int irq)
+{
+ struct irq_desc *desc;
+ int i, ok = 0;
+
+ if (atomic_inc_return(&irq_poll_active) != 1)
+ goto out;
+
+ irq_poll_cpu = smp_processor_id();
+
+ for_each_irq_desc(i, desc) {
+ if (!i)
+ continue;
+
+ if (i == irq) /* Already tried */
+ continue;
+
+ if (try_one_irq(i, desc, false))
+ ok = 1;
+ }
+out:
+ atomic_dec(&irq_poll_active);
+ /* 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;
+
+ if (atomic_inc_return(&irq_poll_active) != 1)
+ goto out;
+ irq_poll_cpu = smp_processor_id();
+
+ for_each_irq_desc(i, desc) {
+ unsigned int state;
+
+ if (!i)
+ continue;
+
+ /* Racy but it doesn't matter */
+ state = desc->istate;
+ barrier();
+ if (!(state & IRQS_SPURIOUS_DISABLED))
+ continue;
+
+ local_irq_disable();
+ try_one_irq(i, desc, true);
+ local_irq_enable();
+ }
+out:
+ atomic_dec(&irq_poll_active);
+ mod_timer(&poll_spurious_irq_timer,
+ jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
+}
+
+static inline int bad_action_ret(irqreturn_t action_ret)
+{
+ if (likely(action_ret <= (IRQ_HANDLED | IRQ_WAKE_THREAD)))
+ return 0;
+ return 1;
+}
+
+/*
+ * 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)
+ */
+static void
+__report_bad_irq(unsigned int irq, struct irq_desc *desc,
+ irqreturn_t action_ret)
+{
+ struct irqaction *action;
+ unsigned long flags;
+
+ if (bad_action_ret(action_ret)) {
+ 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");
+
+ /*
+ * We need to take desc->lock here. note_interrupt() is called
+ * w/o desc->lock held, but IRQ_PROGRESS set. We might race
+ * with something else removing an action. It's ok to take
+ * desc->lock here. See synchronize_irq().
+ */
+ raw_spin_lock_irqsave(&desc->lock, flags);
+ action = desc->action;
+ while (action) {
+ printk(KERN_ERR "[<%p>] %pf", action->handler, action->handler);
+ if (action->thread_fn)
+ printk(KERN_CONT " threaded [<%p>] %pf",
+ action->thread_fn, action->thread_fn);
+ printk(KERN_CONT "\n");
+ action = action->next;
+ }
+ raw_spin_unlock_irqrestore(&desc->lock, flags);
+}
+
+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);
+}
+
+#define SPURIOUS_DEFERRED 0x80000000
+
+void note_interrupt(unsigned int irq, struct irq_desc *desc,
+ irqreturn_t action_ret)
+{
+ if (desc->istate & IRQS_POLL_INPROGRESS ||
+ irq_settings_is_polled(desc))
+ return;
+
+ if (bad_action_ret(action_ret)) {
+ report_bad_irq(irq, desc, action_ret);
+ return;
+ }
+
+ /*
+ * We cannot call note_interrupt from the threaded handler
+ * because we need to look at the compound of all handlers
+ * (primary and threaded). Aside of that in the threaded
+ * shared case we have no serialization against an incoming
+ * hardware interrupt while we are dealing with a threaded
+ * result.
+ *
+ * So in case a thread is woken, we just note the fact and
+ * defer the analysis to the next hardware interrupt.
+ *
+ * The threaded handlers store whether they sucessfully
+ * handled an interrupt and we check whether that number
+ * changed versus the last invocation.
+ *
+ * We could handle all interrupts with the delayed by one
+ * mechanism, but for the non forced threaded case we'd just
+ * add pointless overhead to the straight hardirq interrupts
+ * for the sake of a few lines less code.
+ */
+ if (action_ret & IRQ_WAKE_THREAD) {
+ /*
+ * There is a thread woken. Check whether one of the
+ * shared primary handlers returned IRQ_HANDLED. If
+ * not we defer the spurious detection to the next
+ * interrupt.
+ */
+ if (action_ret == IRQ_WAKE_THREAD) {
+ int handled;
+ /*
+ * We use bit 31 of thread_handled_last to
+ * denote the deferred spurious detection
+ * active. No locking necessary as
+ * thread_handled_last is only accessed here
+ * and we have the guarantee that hard
+ * interrupts are not reentrant.
+ */
+ if (!(desc->threads_handled_last & SPURIOUS_DEFERRED)) {
+ desc->threads_handled_last |= SPURIOUS_DEFERRED;
+ return;
+ }
+ /*
+ * Check whether one of the threaded handlers
+ * returned IRQ_HANDLED since the last
+ * interrupt happened.
+ *
+ * For simplicity we just set bit 31, as it is
+ * set in threads_handled_last as well. So we
+ * avoid extra masking. And we really do not
+ * care about the high bits of the handled
+ * count. We just care about the count being
+ * different than the one we saw before.
+ */
+ handled = atomic_read(&desc->threads_handled);
+ handled |= SPURIOUS_DEFERRED;
+ if (handled != desc->threads_handled_last) {
+ action_ret = IRQ_HANDLED;
+ /*
+ * Note: We keep the SPURIOUS_DEFERRED
+ * bit set. We are handling the
+ * previous invocation right now.
+ * Keep it for the current one, so the
+ * next hardware interrupt will
+ * account for it.
+ */
+ desc->threads_handled_last = handled;
+ } else {
+ /*
+ * None of the threaded handlers felt
+ * responsible for the last interrupt
+ *
+ * We keep the SPURIOUS_DEFERRED bit
+ * set in threads_handled_last as we
+ * need to account for the current
+ * interrupt as well.
+ */
+ action_ret = IRQ_NONE;
+ }
+ } else {
+ /*
+ * One of the primary handlers returned
+ * IRQ_HANDLED. So we don't care about the
+ * threaded handlers on the same line. Clear
+ * the deferred detection bit.
+ *
+ * In theory we could/should check whether the
+ * deferred bit is set and take the result of
+ * the previous run into account here as
+ * well. But it's really not worth the
+ * trouble. If every other interrupt is
+ * handled we never trigger the spurious
+ * detector. And if this is just the one out
+ * of 100k unhandled ones which is handled
+ * then we merily delay the spurious detection
+ * by one hard interrupt. Not a real problem.
+ */
+ desc->threads_handled_last &= ~SPURIOUS_DEFERRED;
+ }
+ }
+
+ if (unlikely(action_ret == IRQ_NONE)) {
+ /*
+ * If we are seeing only the odd spurious IRQ caused by
+ * bus asynchronicity then don't eventually trigger an error,
+ * otherwise the counter 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(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->istate |= IRQS_SPURIOUS_DISABLED;
+ desc->depth++;
+ irq_disable(desc);
+
+ mod_timer(&poll_spurious_irq_timer,
+ jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
+ }
+ desc->irqs_unhandled = 0;
+}
+
+bool 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)
+{
+#ifdef CONFIG_PREEMPT_RT_BASE
+ pr_warn("irqfixup boot option not supported w/ CONFIG_PREEMPT_RT_BASE\n");
+ return 1;
+#endif
+ 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);
+
+static int __init irqpoll_setup(char *str)
+{
+#ifdef CONFIG_PREEMPT_RT_BASE
+ pr_warn("irqpoll boot option not supported w/ CONFIG_PREEMPT_RT_BASE\n");
+ return 1;
+#endif
+ 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);
Code Review / kvmfornfv.git / blobdiff