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authorJiri Slaby <jslaby@suse.cz>2019-07-21 10:23:21 +0200
committerJiri Slaby <jslaby@suse.cz>2019-07-21 10:23:25 +0200
commit7e67ffc6a49bf84a31c1dff35ddc5cbc5c177470 (patch)
treec8f501b44696a54a8007018c520a39620e5d2b6c
parent8bac2bf68cbbf90740935560001b31631f8fa27b (diff)
genirq: Add optional hardware synchronization for shutdown
-rw-r--r--kernel/irq/internals.h4
-rw-r--r--kernel/irq/manage.c75
2 files changed, 60 insertions, 19 deletions
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index 9c957f8b1198..3a948f41ab00 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -97,6 +97,10 @@ static inline void irq_mark_irq(unsigned int irq) { }
extern void irq_mark_irq(unsigned int irq);
#endif
+extern int __irq_get_irqchip_state(struct irq_data *data,
+ enum irqchip_irq_state which,
+ bool *state);
+
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);
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index df8498dcb392..e8f7f179bf77 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -35,8 +35,9 @@ static int __init setup_forced_irqthreads(char *arg)
early_param("threadirqs", setup_forced_irqthreads);
#endif
-static void __synchronize_hardirq(struct irq_desc *desc)
+static void __synchronize_hardirq(struct irq_desc *desc, bool sync_chip)
{
+ struct irq_data *irqd = irq_desc_get_irq_data(desc);
bool inprogress;
do {
@@ -52,6 +53,20 @@ static void __synchronize_hardirq(struct irq_desc *desc)
/* Ok, that indicated we're done: double-check carefully. */
raw_spin_lock_irqsave(&desc->lock, flags);
inprogress = irqd_irq_inprogress(&desc->irq_data);
+
+ /*
+ * If requested and supported, check at the chip whether it
+ * is in flight at the hardware level, i.e. already pending
+ * in a CPU and waiting for service and acknowledge.
+ */
+ if (!inprogress && sync_chip) {
+ /*
+ * Ignore the return code. inprogress is only updated
+ * when the chip supports it.
+ */
+ __irq_get_irqchip_state(irqd, IRQCHIP_STATE_ACTIVE,
+ &inprogress);
+ }
raw_spin_unlock_irqrestore(&desc->lock, flags);
/* Oops, that failed? */
@@ -74,13 +89,18 @@ static void __synchronize_hardirq(struct irq_desc *desc)
* Returns: false if a threaded handler is active.
*
* This function may be called - with care - from IRQ context.
+ *
+ * It does not check whether there is an interrupt in flight at the
+ * hardware level, but not serviced yet, as this might deadlock when
+ * called with interrupts disabled and the target CPU of the interrupt
+ * is the current CPU.
*/
bool synchronize_hardirq(unsigned int irq)
{
struct irq_desc *desc = irq_to_desc(irq);
if (desc) {
- __synchronize_hardirq(desc);
+ __synchronize_hardirq(desc, false);
return !atomic_read(&desc->threads_active);
}
@@ -98,13 +118,17 @@ EXPORT_SYMBOL(synchronize_hardirq);
*
* Can only be called from preemptible code as it might sleep when
* an interrupt thread is associated to @irq.
+ *
+ * It optionally makes sure (when the irq chip supports that method)
+ * that the interrupt is not pending in any CPU and waiting for
+ * service.
*/
void synchronize_irq(unsigned int irq)
{
struct irq_desc *desc = irq_to_desc(irq);
if (desc) {
- __synchronize_hardirq(desc);
+ __synchronize_hardirq(desc, true);
/*
* We made sure that no hardirq handler is
* running. Now verify that no threaded handlers are
@@ -1730,8 +1754,12 @@ static struct irqaction *__free_irq(struct irq_desc *desc, void *dev_id)
unregister_handler_proc(irq, action);
- /* Make sure it's not being used on another CPU: */
- synchronize_hardirq(irq);
+ /*
+ * Make sure it's not being used on another CPU and if the chip
+ * supports it also make sure that there is no (not yet serviced)
+ * interrupt in flight at the hardware level.
+ */
+ __synchronize_hardirq(desc, true);
#ifdef CONFIG_DEBUG_SHIRQ
/*
@@ -2589,6 +2617,28 @@ out:
irq_put_desc_unlock(desc, flags);
}
+int __irq_get_irqchip_state(struct irq_data *data, enum irqchip_irq_state which,
+ bool *state)
+{
+ struct irq_chip *chip;
+ int err = -EINVAL;
+
+ do {
+ chip = irq_data_get_irq_chip(data);
+ if (chip->irq_get_irqchip_state)
+ break;
+#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
+ data = data->parent_data;
+#else
+ data = NULL;
+#endif
+ } while (data);
+
+ if (data)
+ err = chip->irq_get_irqchip_state(data, which, state);
+ return err;
+}
+
/**
* irq_get_irqchip_state - returns the irqchip state of a interrupt.
* @irq: Interrupt line that is forwarded to a VM
@@ -2607,7 +2657,6 @@ int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
{
struct irq_desc *desc;
struct irq_data *data;
- struct irq_chip *chip;
unsigned long flags;
int err = -EINVAL;
@@ -2617,19 +2666,7 @@ int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
data = irq_desc_get_irq_data(desc);
- do {
- chip = irq_data_get_irq_chip(data);
- if (chip->irq_get_irqchip_state)
- break;
-#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
- data = data->parent_data;
-#else
- data = NULL;
-#endif
- } while (data);
-
- if (data)
- err = chip->irq_get_irqchip_state(data, which, state);
+ err = __irq_get_irqchip_state(data, which, state);
irq_put_desc_busunlock(desc, flags);
return err;