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Commit 217d453d authored by Yang Yingliang's avatar Yang Yingliang Committed by Catalin Marinas
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arm64: fix a migrating irq bug when hotplug cpu 



When cpu is disabled, all irqs will be migratged to another cpu.
In some cases, a new affinity is different, the old affinity need
to be updated and if irq_set_affinity's return value is IRQ_SET_MASK_OK_DONE,
the old affinity can not be updated. Fix it by using irq_do_set_affinity.

And migrating interrupts is a core code matter, so use the generic
function irq_migrate_all_off_this_cpu() to migrate interrupts in
kernel/irq/migration.c.

Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Acked-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent a78afccb

arch/arm64/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -427,6 +427,7 @@ config NR_CPUS 


config HOTPLUG_CPU

	bool "Support for hot-pluggable CPUs"

	select GENERIC_IRQ_MIGRATION

	help

	  Say Y here to experiment with turning CPUs off and on.  CPUs

	  can be controlled through /sys/devices/system/cpu.

arch/arm64/include/asm/irq.h

+0 −1
Original line number Diff line number Diff line
@@ -7,7 +7,6 @@ 


struct pt_regs;



extern void migrate_irqs(void);

extern void set_handle_irq(void (*handle_irq)(struct pt_regs *));



static inline void acpi_irq_init(void)

arch/arm64/kernel/irq.c

+0 −62
Original line number Diff line number Diff line
@@ -27,7 +27,6 @@ 
#include <linux/init.h>

#include <linux/irqchip.h>

#include <linux/seq_file.h>

#include <linux/ratelimit.h>



unsigned long irq_err_count;
@@ -54,64 +53,3 @@ 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 = irq_data_get_affinity_mask(d);

	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, false) == IRQ_SET_MASK_OK && ret)

		cpumask_copy(irq_data_get_affinity_mask(d), 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 */

arch/arm64/kernel/smp.c

+2 −1
Original line number Diff line number Diff line
@@ -231,7 +231,8 @@ int __cpu_disable(void) 
	/*

	 * OK - migrate IRQs away from this CPU

	 */

	migrate_irqs();

	irq_migrate_all_off_this_cpu();



	return 0;

}