Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[~andy/linux] / arch / arm64 / kernel / irq.c

diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
index ecb3354292ed2af479aa7d3df33c1d3100dfdd4e..473e5dbf8f39a39e8eaa7a0740e54ee4d6bacb59 100644 (file)
--- a/arch/arm64/kernel/irq.c
+++ b/arch/arm64/kernel/irq.c
@@ -81,3 +81,64 @@ void __init init_IRQ(void)
        if (!handle_arch_irq)
                panic("No interrupt controller found.");
 }
+
+#ifdef CONFIG_HOTPLUG_CPU
+static bool migrate_one_irq(struct irq_desc *desc)
+{
+       struct irq_data *d = irq_desc_get_irq_data(desc);
+       const struct cpumask *affinity = d->affinity;
+       struct irq_chip *c;
+       bool ret = false;
+
+       /*
+        * If this is a per-CPU interrupt, or the affinity does not
+        * include this CPU, then we have nothing to do.
+        */
+       if (irqd_is_per_cpu(d) || !cpumask_test_cpu(smp_processor_id(), affinity))
+               return false;
+
+       if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
+               affinity = cpu_online_mask;
+               ret = true;
+       }
+
+       c = irq_data_get_irq_chip(d);
+       if (!c->irq_set_affinity)
+               pr_debug("IRQ%u: unable to set affinity\n", d->irq);
+       else if (c->irq_set_affinity(d, affinity, true) == IRQ_SET_MASK_OK && ret)
+               cpumask_copy(d->affinity, affinity);
+
+       return ret;
+}
+
+/*
+ * The current CPU has been marked offline.  Migrate IRQs off this CPU.
+ * If the affinity settings do not allow other CPUs, force them onto any
+ * available CPU.
+ *
+ * Note: we must iterate over all IRQs, whether they have an attached
+ * action structure or not, as we need to get chained interrupts too.
+ */
+void migrate_irqs(void)
+{
+       unsigned int i;
+       struct irq_desc *desc;
+       unsigned long flags;
+
+       local_irq_save(flags);
+
+       for_each_irq_desc(i, desc) {
+               bool affinity_broken;
+
+               raw_spin_lock(&desc->lock);
+               affinity_broken = migrate_one_irq(desc);
+               raw_spin_unlock(&desc->lock);
+
+               if (affinity_broken)
+                       pr_warn_ratelimited("IRQ%u no longer affine to CPU%u\n",
+                                           i, smp_processor_id());
+       }
+
+       local_irq_restore(flags);
+}
+#endif /* CONFIG_HOTPLUG_CPU */