root/kernel/irq/migration.c
// SPDX-License-Identifier: GPL-2.0

#include <linux/irq.h>
#include <linux/interrupt.h>

#include "internals.h"

/**
 * irq_fixup_move_pending - Cleanup irq move pending from a dying CPU
 * @desc:               Interrupt descriptor to clean up
 * @force_clear:        If set clear the move pending bit unconditionally.
 *                      If not set, clear it only when the dying CPU is the
 *                      last one in the pending mask.
 *
 * Returns true if the pending bit was set and the pending mask contains an
 * online CPU other than the dying CPU.
 */
bool irq_fixup_move_pending(struct irq_desc *desc, bool force_clear)
{
        struct irq_data *data = irq_desc_get_irq_data(desc);

        if (!irqd_is_setaffinity_pending(data))
                return false;

        /*
         * The outgoing CPU might be the last online target in a pending
         * interrupt move. If that's the case clear the pending move bit.
         */
        if (!cpumask_intersects(desc->pending_mask, cpu_online_mask)) {
                irqd_clr_move_pending(data);
                return false;
        }
        if (force_clear)
                irqd_clr_move_pending(data);
        return true;
}

void irq_force_complete_move(struct irq_desc *desc)
{
        for (struct irq_data *d = irq_desc_get_irq_data(desc); d; d = irqd_get_parent_data(d)) {
                if (d->chip && d->chip->irq_force_complete_move) {
                        d->chip->irq_force_complete_move(d);
                        return;
                }
        }
}

void irq_move_masked_irq(struct irq_data *idata)
{
        struct irq_desc *desc = irq_data_to_desc(idata);
        struct irq_data *data = &desc->irq_data;
        struct irq_chip *chip = data->chip;

        if (likely(!irqd_is_setaffinity_pending(data)))
                return;

        irqd_clr_move_pending(data);

        /*
         * Paranoia: cpu-local interrupts shouldn't be calling in here anyway.
         */
        if (irqd_is_per_cpu(data)) {
                WARN_ON(1);
                return;
        }

        if (unlikely(cpumask_empty(desc->pending_mask)))
                return;

        if (!chip->irq_set_affinity)
                return;

        assert_raw_spin_locked(&desc->lock);

        /*
         * If there was a valid mask to work with, please
         * do the disable, re-program, enable sequence.
         * This is *not* particularly important for level triggered
         * but in a edge trigger case, we might be setting rte
         * when an active trigger is coming in. This could
         * cause some ioapics to mal-function.
         * Being paranoid i guess!
         *
         * For correct operation this depends on the caller
         * masking the irqs.
         */
        if (cpumask_intersects(desc->pending_mask, cpu_online_mask)) {
                int ret;

                ret = irq_do_set_affinity(data, desc->pending_mask, false);
                /*
                 * If the there is a cleanup pending in the underlying
                 * vector management, reschedule the move for the next
                 * interrupt. Leave desc->pending_mask intact.
                 */
                if (ret == -EBUSY) {
                        irqd_set_move_pending(data);
                        return;
                }
        }
        cpumask_clear(desc->pending_mask);
}

void __irq_move_irq(struct irq_data *idata)
{
        bool masked;

        /*
         * Get top level irq_data when CONFIG_IRQ_DOMAIN_HIERARCHY is enabled,
         * and it should be optimized away when CONFIG_IRQ_DOMAIN_HIERARCHY is
         * disabled. So we avoid an "#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY" here.
         */
        idata = irq_desc_get_irq_data(irq_data_to_desc(idata));

        if (unlikely(irqd_irq_disabled(idata)))
                return;

        /*
         * Be careful vs. already masked interrupts. If this is a
         * threaded interrupt with ONESHOT set, we can end up with an
         * interrupt storm.
         */
        masked = irqd_irq_masked(idata);
        if (!masked)
                idata->chip->irq_mask(idata);
        irq_move_masked_irq(idata);
        if (!masked)
                idata->chip->irq_unmask(idata);
}

bool irq_can_move_in_process_context(struct irq_data *data)
{
        /*
         * Get the top level irq_data in the hierarchy, which is optimized
         * away when CONFIG_IRQ_DOMAIN_HIERARCHY is disabled.
         */
        data = irq_desc_get_irq_data(irq_data_to_desc(data));
        return irq_can_move_pcntxt(data);
}