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authorKeith Busch <keith.busch@intel.com>2016-06-17 16:00:20 -0600
committerThomas Gleixner <tglx@linutronix.de>2016-06-18 10:00:55 +0200
commitedd14cfebc4404698544d407ecf8eda6e19aa19e (patch)
treec8e821937f59152ba61129fdcfda0d52416302f8 /kernel/irq
parent21c57fd135894f69ba2b8acc715ca81e90eeba15 (diff)
downloadlinux-stericsson-edd14cfebc4404698544d407ecf8eda6e19aa19e.tar.gz
genirq: Add untracked irq handler
This adds a software irq handler for controllers that multiplex interrupts from multiple devices, but don't know which device generated the interrupt. For these devices, the irq handler that demuxes must check every action for every software irq using the same h/w irq in order to find out which device generated the interrupt. This will inevitably trigger spurious interrupt detection if we are noting the irq. The new irq handler does not track the handling for spurious interrupt detection. An irq that uses this also won't get stats tracked since it didn't generate the interrupt, nor added to randomness since they are not random. Signed-off-by: Keith Busch <keith.busch@intel.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: linux-pci@vger.kernel.org Cc: Jon Derrick <jonathan.derrick@intel.com> Link: http://lkml.kernel.org/r/1466200821-29159-1-git-send-email-keith.busch@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/irq')
-rw-r--r--kernel/irq/chip.c43
-rw-r--r--kernel/irq/handle.c18
-rw-r--r--kernel/irq/internals.h1
3 files changed, 58 insertions, 4 deletions
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index ad8131473774..b4c1bc7c9ca2 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -426,6 +426,49 @@ out_unlock:
}
EXPORT_SYMBOL_GPL(handle_simple_irq);
+/**
+ * handle_untracked_irq - Simple and software-decoded IRQs.
+ * @desc: the interrupt description structure for this irq
+ *
+ * Untracked interrupts are sent from a demultiplexing interrupt
+ * handler when the demultiplexer does not know which device it its
+ * multiplexed irq domain generated the interrupt. IRQ's handled
+ * through here are not subjected to stats tracking, randomness, or
+ * spurious interrupt detection.
+ *
+ * Note: Like handle_simple_irq, the caller is expected to handle
+ * the ack, clear, mask and unmask issues if necessary.
+ */
+void handle_untracked_irq(struct irq_desc *desc)
+{
+ unsigned int flags = 0;
+
+ raw_spin_lock(&desc->lock);
+
+ if (!irq_may_run(desc))
+ goto out_unlock;
+
+ desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
+
+ if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) {
+ desc->istate |= IRQS_PENDING;
+ goto out_unlock;
+ }
+
+ desc->istate &= ~IRQS_PENDING;
+ irqd_set(&desc->irq_data, IRQD_IRQ_INPROGRESS);
+ raw_spin_unlock(&desc->lock);
+
+ __handle_irq_event_percpu(desc, &flags);
+
+ raw_spin_lock(&desc->lock);
+ irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
+
+out_unlock:
+ raw_spin_unlock(&desc->lock);
+}
+EXPORT_SYMBOL_GPL(handle_untracked_irq);
+
/*
* Called unconditionally from handle_level_irq() and only for oneshot
* interrupts from handle_fasteoi_irq()
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index a15b5485b446..d3f24905852c 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -132,10 +132,10 @@ void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action)
wake_up_process(action->thread);
}
-irqreturn_t handle_irq_event_percpu(struct irq_desc *desc)
+irqreturn_t __handle_irq_event_percpu(struct irq_desc *desc, unsigned int *flags)
{
irqreturn_t retval = IRQ_NONE;
- unsigned int flags = 0, irq = desc->irq_data.irq;
+ unsigned int irq = desc->irq_data.irq;
struct irqaction *action;
for_each_action_of_desc(desc, action) {
@@ -164,7 +164,7 @@ irqreturn_t handle_irq_event_percpu(struct irq_desc *desc)
/* Fall through to add to randomness */
case IRQ_HANDLED:
- flags |= action->flags;
+ *flags |= action->flags;
break;
default:
@@ -174,7 +174,17 @@ irqreturn_t handle_irq_event_percpu(struct irq_desc *desc)
retval |= res;
}
- add_interrupt_randomness(irq, flags);
+ 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, flags);
if (!noirqdebug)
note_interrupt(desc, retval);
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index d5edcdc9382a..0c6f35ba9cc0 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -84,6 +84,7 @@ extern void irq_mark_irq(unsigned int irq);
extern void init_kstat_irqs(struct irq_desc *desc, int node, int nr);
+irqreturn_t __handle_irq_event_percpu(struct irq_desc *desc, unsigned int *flags);
irqreturn_t handle_irq_event_percpu(struct irq_desc *desc);
irqreturn_t handle_irq_event(struct irq_desc *desc);