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ARM: 8824/1: fix a migrating irq bug when hotplug cpu 

Arm TC2 fails cpu hotplug stress test.

This issue was tracked down to a missing copy of the new affinity
cpumask for the vexpress-spc interrupt into struct
irq_common_data.affinity when the interrupt is migrated in
migrate_one_irq().

Fix it by replacing the arm specific hotplug cpu migration with the
generic irq code.

This is the counterpart implementation to commit 217d453d47 ("arm64:
fix a migrating irq bug when hotplug cpu").

Tested with cpu hotplug stress test on Arm TC2 (multi_v7_defconfig plus
CONFIG_ARM_BIG_LITTLE_CPUFREQ=y and CONFIG_ARM_VEXPRESS_SPC_CPUFREQ=y).
The vexpress-spc interrupt (irq=22) on this board is affine to CPU0.
Its affinity cpumask now changes correctly e.g. from 0 to 1-4 when
CPU0 is hotplugged out.

Suggested-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
This commit is contained in:
Dietmar Eggemann 2019-01-21 14:42:42 +01:00 committed by Russell King
parent bfeffd1552
commit 1b5ba35078
4 changed files with 2 additions and 64 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/arm/Kconfig
View File

@ -1400,6 +1400,7 @@ config NR_CPUS
config HOTPLUG_CPU
bool "Support for hot-pluggable CPUs"
depends on SMP
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.

1
arch/arm/include/asm/irq.h
View File

@ -25,7 +25,6 @@
#ifndef __ASSEMBLY__
struct irqaction;
struct pt_regs;
extern void migrate_irqs(void);
extern void asm_do_IRQ(unsigned int, struct pt_regs *);
void handle_IRQ(unsigned int, struct pt_regs *);

62
arch/arm/kernel/irq.c
View File

@ -31,7 +31,6 @@
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/seq_file.h>
#include <linux/ratelimit.h>
#include <linux/errno.h>
#include <linux/list.h>
#include <linux/kallsyms.h>
@ -109,64 +108,3 @@ int __init arch_probe_nr_irqs(void)
return nr_irqs;
}
#endif
#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 */

2
arch/arm/kernel/smp.c
View File

@ -254,7 +254,7 @@ int __cpu_disable(void)
/*
* OK - migrate IRQs away from this CPU
*/
migrate_irqs();
irq_migrate_all_off_this_cpu();
/*
* Flush user cache and TLB mappings, and then remove this CPU