[ARM SMP] Add hotplug CPU infrastructure
This patch adds the infrastructure to support hotplug CPU on ARM
platforms.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/irq.c b/arch/arm/kernel/irq.c
index 3284118..9def440 100644
--- a/arch/arm/kernel/irq.c
+++ b/arch/arm/kernel/irq.c
@@ -1050,3 +1050,34 @@
}
__setup("noirqdebug", noirqdebug_setup);
+
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * The 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.
+ */
+void migrate_irqs(void)
+{
+ unsigned int i, cpu = smp_processor_id();
+
+ for (i = 0; i < NR_IRQS; i++) {
+ struct irqdesc *desc = irq_desc + i;
+
+ if (desc->cpu == cpu) {
+ unsigned int newcpu = any_online_cpu(desc->affinity);
+
+ if (newcpu == NR_CPUS) {
+ if (printk_ratelimit())
+ printk(KERN_INFO "IRQ%u no longer affine to CPU%u\n",
+ i, cpu);
+
+ cpus_setall(desc->affinity);
+ newcpu = any_online_cpu(desc->affinity);
+ }
+
+ route_irq(desc, i, newcpu);
+ }
+ }
+}
+#endif /* CONFIG_HOTPLUG_CPU */