Merge branch 'irq/for-arm' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

* 'irq/for-arm' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq: Introduce generic irq migration for cpu hotunplug

4 files changed, 89 insertions, 0 deletions

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 11bf09288ddb..45cc7299bb61 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -452,6 +452,8 @@ extern int irq_set_affinity_locked(struct irq_data *data,
                                    const struct cpumask *cpumask, bool force);
 extern int irq_set_vcpu_affinity(unsigned int irq, void *vcpu_info);
 
+extern void irq_migrate_all_off_this_cpu(void);
+
 #if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_PENDING_IRQ)
 void irq_move_irq(struct irq_data *data);
 void irq_move_masked_irq(struct irq_data *data);
diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
index 9a76e3beda54..3b48dab80164 100644
--- a/kernel/irq/Kconfig
+++ b/kernel/irq/Kconfig
@@ -30,6 +30,10 @@ config GENERIC_IRQ_LEGACY_ALLOC_HWIRQ
 config GENERIC_PENDING_IRQ
         bool
 
+# Support for generic irq migrating off cpu before the cpu is offline.
+config GENERIC_IRQ_MIGRATION
+        bool
+
 # Alpha specific irq affinity mechanism
 config AUTO_IRQ_AFFINITY
        bool
diff --git a/kernel/irq/Makefile b/kernel/irq/Makefile
index d12123526e2b..2fc9cbdf35b6 100644
--- a/kernel/irq/Makefile
+++ b/kernel/irq/Makefile
@@ -5,5 +5,6 @@ obj-$(CONFIG_GENERIC_IRQ_PROBE) += autoprobe.o
 obj-$(CONFIG_IRQ_DOMAIN) += irqdomain.o
 obj-$(CONFIG_PROC_FS) += proc.o
 obj-$(CONFIG_GENERIC_PENDING_IRQ) += migration.o
+obj-$(CONFIG_GENERIC_IRQ_MIGRATION) += cpuhotplug.o
 obj-$(CONFIG_PM_SLEEP) += pm.o
 obj-$(CONFIG_GENERIC_MSI_IRQ) += msi.o
diff --git a/kernel/irq/cpuhotplug.c b/kernel/irq/cpuhotplug.c
new file mode 100644
index 000000000000..80f4f4e56fed
--- /dev/null
+++ b/kernel/irq/cpuhotplug.c
@@ -0,0 +1,82 @@
+/*
+ * Generic cpu hotunplug interrupt migration code copied from the
+ * arch/arm implementation
+ *
+ * Copyright (C) Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/interrupt.h>
+#include <linux/ratelimit.h>
+#include <linux/irq.h>
+
+#include "internals.h"
+
+static bool migrate_one_irq(struct irq_desc *desc)
+{
+        struct irq_data *d = irq_desc_get_irq_data(desc);
+        const struct cpumask *affinity = d->common->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_warn_ratelimited("IRQ%u: unable to set affinity\n", d->irq);
+        } else {
+                int r = irq_do_set_affinity(d, affinity, false);
+                if (r)
+                        pr_warn_ratelimited("IRQ%u: set affinity failed(%d).\n",
+                                            d->irq, r);
+        }
+
+        return ret;
+}
+
+/**
+ * irq_migrate_all_off_this_cpu - Migrate irqs away from offline cpu
+ *
+ * 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 irq_migrate_all_off_this_cpu(void)
+{
+        unsigned int irq;
+        struct irq_desc *desc;
+        unsigned long flags;
+
+        local_irq_save(flags);
+
+        for_each_active_irq(irq) {
+                bool affinity_broken;
+
+                desc = irq_to_desc(irq);
+                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",
+                                            irq, smp_processor_id());
+        }
+
+        local_irq_restore(flags);
+}