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Diffstat (limited to 'kernel/irq/handle.c')
-rw-r--r--kernel/irq/handle.c144
1 files changed, 113 insertions, 31 deletions
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 3540a7190122..517561fc7317 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -51,30 +51,92 @@ static void warn_no_thread(unsigned int irq, struct irqaction *action)
"but no thread function available.", irq, action->name);
}
-/**
- * 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)
+static void irq_wake_thread(struct irq_desc *desc, struct irqaction *action)
+{
+ /*
+ * Wake up the handler thread for this 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 the
+ * RUNTHREAD bit is already set, nothing to do.
+ */
+ if (test_bit(IRQTF_DIED, &action->thread_flags) ||
+ 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;
+ wake_up_process(action->thread);
+}
+
+irqreturn_t
+handle_irq_event_percpu(struct irq_desc *desc, struct irqaction *action)
{
- irqreturn_t ret, retval = IRQ_NONE;
- unsigned int status = 0;
+ irqreturn_t retval = IRQ_NONE;
+ unsigned int random = 0, irq = desc->irq_data.irq;
do {
+ irqreturn_t res;
+
trace_irq_handler_entry(irq, action);
- ret = action->handler(irq, action->dev_id);
- trace_irq_handler_exit(irq, action, ret);
+ res = action->handler(irq, action->dev_id);
+ trace_irq_handler_exit(irq, action, res);
- switch (ret) {
+ if (WARN_ONCE(!irqs_disabled(),"irq %u handler %pF enabled interrupts\n",
+ irq, action->handler))
+ local_irq_disable();
+
+ switch (res) {
case IRQ_WAKE_THREAD:
/*
* Set result to handled so the spurious check
* does not trigger.
*/
- ret = IRQ_HANDLED;
+ res = IRQ_HANDLED;
/*
* Catch drivers which return WAKE_THREAD but
@@ -85,36 +147,56 @@ irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
break;
}
- /*
- * Wake up the handler thread for this
- * action. In case the thread crashed and was
- * killed we just pretend that we handled the
- * interrupt. The hardirq handler above has
- * disabled the device interrupt, so no irq
- * storm is lurking.
- */
- if (likely(!test_bit(IRQTF_DIED,
- &action->thread_flags))) {
- set_bit(IRQTF_RUNTHREAD, &action->thread_flags);
- wake_up_process(action->thread);
- }
+ irq_wake_thread(desc, action);
/* Fall through to add to randomness */
case IRQ_HANDLED:
- status |= action->flags;
+ random |= action->flags;
break;
default:
break;
}
- retval |= ret;
+ retval |= res;
action = action->next;
} while (action);
- if (status & IRQF_SAMPLE_RANDOM)
+ if (random & IRQF_SAMPLE_RANDOM)
add_interrupt_randomness(irq);
- local_irq_disable();
+ if (!noirqdebug)
+ note_interrupt(irq, desc, retval);
return retval;
}
+
+irqreturn_t handle_irq_event(struct irq_desc *desc)
+{
+ struct irqaction *action = desc->action;
+ irqreturn_t ret;
+
+ irq_compat_clr_pending(desc);
+ desc->istate &= ~IRQS_PENDING;
+ irq_compat_set_progress(desc);
+ desc->istate |= IRQS_INPROGRESS;
+ raw_spin_unlock(&desc->lock);
+
+ ret = handle_irq_event_percpu(desc, action);
+
+ raw_spin_lock(&desc->lock);
+ desc->istate &= ~IRQS_INPROGRESS;
+ irq_compat_clr_progress(desc);
+ return ret;
+}
+
+/**
+ * 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)
+{
+ return handle_irq_event_percpu(irq_to_desc(irq), action);
+}