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authorCatalin Marinas <catalin.marinas@arm.com>2015-10-09 16:47:34 +0100
committerCatalin Marinas <catalin.marinas@arm.com>2015-10-09 16:47:34 +0100
commita78afccbbaa6d2df49768cabad8af28a0a84181d (patch)
treea14d9ddea49c27df575fd6c029baad80b8b03a75 /kernel/irq
parent348a65cdcbbf243073ee39d1f7d4413081ad7eab (diff)
parentf1e0bb0ad473a32d1b7e6d285ae9f7e47710bb5e (diff)
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
Diffstat (limited to 'kernel/irq')
-rw-r--r--kernel/irq/Kconfig4
-rw-r--r--kernel/irq/Makefile1
-rw-r--r--kernel/irq/cpuhotplug.c82
3 files changed, 87 insertions, 0 deletions
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);
+}