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601c942176
Commit 01f8fa4f01d8("genirq: Allow forcing cpu affinity of interrupts")
enabled the forced irq_set_affinity which previously refused to route an
interrupt to an offline cpu.
Commit ffde1de64012("irqchip: Gic: Support forced affinity setting")
implements this force logic and disables the cpu online check for GIC
interrupt controller.
When __cpu_disable calls migrate_irqs, it disables the current cpu in
cpu_online_mask and uses forced irq_set_affinity to migrate the IRQs
away from the cpu but passes affinity mask with the cpu being offlined
also included in it.
When calling irq_set_affinity with force == true in a cpu hotplug path,
the caller must ensure that the cpu being offlined is not present in the
affinity mask or it may be selected as the target CPU, leading to the
interrupt not being migrated.
This patch uses cpu_online_mask when using forced irq_set_affinity so
that the IRQs are properly migrated away.
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
149 lines
3.9 KiB
C
149 lines
3.9 KiB
C
/*
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* Based on arch/arm/kernel/irq.c
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*
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* Copyright (C) 1992 Linus Torvalds
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* Modifications for ARM processor Copyright (C) 1995-2000 Russell King.
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* Support for Dynamic Tick Timer Copyright (C) 2004-2005 Nokia Corporation.
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* Dynamic Tick Timer written by Tony Lindgren <tony@atomide.com> and
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* Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>.
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* Copyright (C) 2012 ARM Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/kernel_stat.h>
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#include <linux/irq.h>
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#include <linux/smp.h>
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#include <linux/init.h>
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#include <linux/irqchip.h>
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#include <linux/seq_file.h>
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#include <linux/ratelimit.h>
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unsigned long irq_err_count;
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int arch_show_interrupts(struct seq_file *p, int prec)
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{
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#ifdef CONFIG_SMP
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show_ipi_list(p, prec);
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#endif
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seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count);
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return 0;
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}
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/*
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* handle_IRQ handles all hardware IRQ's. Decoded IRQs should
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* not come via this function. Instead, they should provide their
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* own 'handler'. Used by platform code implementing C-based 1st
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* level decoding.
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*/
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void handle_IRQ(unsigned int irq, struct pt_regs *regs)
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{
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struct pt_regs *old_regs = set_irq_regs(regs);
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irq_enter();
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/*
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* Some hardware gives randomly wrong interrupts. Rather
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* than crashing, do something sensible.
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*/
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if (unlikely(irq >= nr_irqs)) {
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pr_warn_ratelimited("Bad IRQ%u\n", irq);
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ack_bad_irq(irq);
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} else {
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generic_handle_irq(irq);
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}
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irq_exit();
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set_irq_regs(old_regs);
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}
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void __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
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{
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if (handle_arch_irq)
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return;
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handle_arch_irq = handle_irq;
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}
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void __init init_IRQ(void)
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{
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irqchip_init();
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if (!handle_arch_irq)
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panic("No interrupt controller found.");
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}
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#ifdef CONFIG_HOTPLUG_CPU
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static bool migrate_one_irq(struct irq_desc *desc)
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{
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struct irq_data *d = irq_desc_get_irq_data(desc);
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const struct cpumask *affinity = d->affinity;
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struct irq_chip *c;
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bool ret = false;
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/*
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* If this is a per-CPU interrupt, or the affinity does not
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* include this CPU, then we have nothing to do.
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*/
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if (irqd_is_per_cpu(d) || !cpumask_test_cpu(smp_processor_id(), affinity))
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return false;
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if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids)
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ret = true;
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/*
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* when using forced irq_set_affinity we must ensure that the cpu
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* being offlined is not present in the affinity mask, it may be
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* selected as the target CPU otherwise
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*/
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affinity = cpu_online_mask;
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c = irq_data_get_irq_chip(d);
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if (!c->irq_set_affinity)
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pr_debug("IRQ%u: unable to set affinity\n", d->irq);
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else if (c->irq_set_affinity(d, affinity, true) == IRQ_SET_MASK_OK && ret)
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cpumask_copy(d->affinity, affinity);
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return ret;
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}
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/*
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* The current CPU has been marked offline. Migrate IRQs off this CPU.
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* If the affinity settings do not allow other CPUs, force them onto any
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* available CPU.
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*
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* Note: we must iterate over all IRQs, whether they have an attached
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* action structure or not, as we need to get chained interrupts too.
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*/
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void migrate_irqs(void)
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{
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unsigned int i;
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struct irq_desc *desc;
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unsigned long flags;
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local_irq_save(flags);
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for_each_irq_desc(i, desc) {
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bool affinity_broken;
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raw_spin_lock(&desc->lock);
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affinity_broken = migrate_one_irq(desc);
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raw_spin_unlock(&desc->lock);
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if (affinity_broken)
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pr_warn_ratelimited("IRQ%u no longer affine to CPU%u\n",
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i, smp_processor_id());
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}
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local_irq_restore(flags);
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}
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#endif /* CONFIG_HOTPLUG_CPU */
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