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authorJohn Garry <john.garry@huawei.com>2020-12-02 18:36:53 +0800
committerMarc Zyngier <maz@kernel.org>2020-12-11 14:47:50 +0000
commit1d3aec89286254487df7641c30f1b14ad1d127a5 (patch)
tree8e0bd644010b822c017c65f4610732e2752a9db7 /kernel/irq
parent34dd263fce3114147f21698f8e55e05b9e8185bd (diff)
downloadlinux-stericsson-1d3aec89286254487df7641c30f1b14ad1d127a5.tar.gz
genirq/affinity: Add irq_update_affinity_desc()
Add a function to allow the affinity of an interrupt be switched to managed, such that interrupts allocated for platform devices may be managed. This new interface has certain limitations, and attempts to use it in the following circumstances will fail: - For when the kernel is configured for generic IRQ reservation mode (in config GENERIC_IRQ_RESERVATION_MODE). The reason being that it could conflict with managed vs. non-managed interrupt accounting. - The interrupt is already started, which should not be the case during init - The interrupt is already configured as managed, which means double init Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Garry <john.garry@huawei.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/1606905417-183214-2-git-send-email-john.garry@huawei.com
Diffstat (limited to 'kernel/irq')
-rw-r--r--kernel/irq/manage.c70
1 files changed, 70 insertions, 0 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index c460e0496006..c826ba4141fe 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -371,6 +371,76 @@ int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
return ret;
}
+/**
+ * irq_update_affinity_desc - Update affinity management for an interrupt
+ * @irq: The interrupt number to update
+ * @affinity: Pointer to the affinity descriptor
+ *
+ * This interface can be used to configure the affinity management of
+ * interrupts which have been allocated already.
+ *
+ * There are certain limitations on when it may be used - attempts to use it
+ * for when the kernel is configured for generic IRQ reservation mode (in
+ * config GENERIC_IRQ_RESERVATION_MODE) will fail, as it may conflict with
+ * managed/non-managed interrupt accounting. In addition, attempts to use it on
+ * an interrupt which is already started or which has already been configured
+ * as managed will also fail, as these mean invalid init state or double init.
+ */
+int irq_update_affinity_desc(unsigned int irq,
+ struct irq_affinity_desc *affinity)
+{
+ struct irq_desc *desc;
+ unsigned long flags;
+ bool activated;
+ int ret = 0;
+
+ /*
+ * Supporting this with the reservation scheme used by x86 needs
+ * some more thought. Fail it for now.
+ */
+ if (IS_ENABLED(CONFIG_GENERIC_IRQ_RESERVATION_MODE))
+ return -EOPNOTSUPP;
+
+ desc = irq_get_desc_buslock(irq, &flags, 0);
+ if (!desc)
+ return -EINVAL;
+
+ /* Requires the interrupt to be shut down */
+ if (irqd_is_started(&desc->irq_data)) {
+ ret = -EBUSY;
+ goto out_unlock;
+ }
+
+ /* Interrupts which are already managed cannot be modified */
+ if (irqd_affinity_is_managed(&desc->irq_data)) {
+ ret = -EBUSY;
+ goto out_unlock;
+ }
+
+ /*
+ * Deactivate the interrupt. That's required to undo
+ * anything an earlier activation has established.
+ */
+ activated = irqd_is_activated(&desc->irq_data);
+ if (activated)
+ irq_domain_deactivate_irq(&desc->irq_data);
+
+ if (affinity->is_managed) {
+ irqd_set(&desc->irq_data, IRQD_AFFINITY_MANAGED);
+ irqd_set(&desc->irq_data, IRQD_MANAGED_SHUTDOWN);
+ }
+
+ cpumask_copy(desc->irq_common_data.affinity, &affinity->mask);
+
+ /* Restore the activation state */
+ if (activated)
+ irq_domain_activate_irq(&desc->irq_data, false);
+
+out_unlock:
+ irq_put_desc_busunlock(desc, flags);
+ return ret;
+}
+
int __irq_set_affinity(unsigned int irq, const struct cpumask *mask, bool force)
{
struct irq_desc *desc = irq_to_desc(irq);