LXR linux/kernel/irq/migration.c

   1// SPDX-License-Identifier: GPL-2.0
   2
   3#include <linux/irq.h>
   4#include <linux/interrupt.h>
   5
   6#include "internals.h"
   7
   8/**
   9 * irq_fixup_move_pending - Cleanup irq move pending from a dying CPU
  10 * @desc:               Interrupt descpriptor to clean up
  11 * @force_clear:        If set clear the move pending bit unconditionally.
  12 *                      If not set, clear it only when the dying CPU is the
  13 *                      last one in the pending mask.
  14 *
  15 * Returns true if the pending bit was set and the pending mask contains an
  16 * online CPU other than the dying CPU.
  17 */
  18bool irq_fixup_move_pending(struct irq_desc *desc, bool force_clear)
  19{
  20        struct irq_data *data = irq_desc_get_irq_data(desc);
  21
  22        if (!irqd_is_setaffinity_pending(data))
  23                return false;
  24
  25        /*
  26         * The outgoing CPU might be the last online target in a pending
  27         * interrupt move. If that's the case clear the pending move bit.
  28         */
  29        if (cpumask_any_and(desc->pending_mask, cpu_online_mask) >= nr_cpu_ids) {
  30                irqd_clr_move_pending(data);
  31                return false;
  32        }
  33        if (force_clear)
  34                irqd_clr_move_pending(data);
  35        return true;
  36}
  37
  38void irq_move_masked_irq(struct irq_data *idata)
  39{
  40        struct irq_desc *desc = irq_data_to_desc(idata);
  41        struct irq_data *data = &desc->irq_data;
  42        struct irq_chip *chip = data->chip;
  43
  44        if (likely(!irqd_is_setaffinity_pending(data)))
  45                return;
  46
  47        irqd_clr_move_pending(data);
  48
  49        /*
  50         * Paranoia: cpu-local interrupts shouldn't be calling in here anyway.
  51         */
  52        if (irqd_is_per_cpu(data)) {
  53                WARN_ON(1);
  54                return;
  55        }
  56
  57        if (unlikely(cpumask_empty(desc->pending_mask)))
  58                return;
  59
  60        if (!chip->irq_set_affinity)
  61                return;
  62
  63        assert_raw_spin_locked(&desc->lock);
  64
  65        /*
  66         * If there was a valid mask to work with, please
  67         * do the disable, re-program, enable sequence.
  68         * This is *not* particularly important for level triggered
  69         * but in a edge trigger case, we might be setting rte
  70         * when an active trigger is coming in. This could
  71         * cause some ioapics to mal-function.
  72         * Being paranoid i guess!
  73         *
  74         * For correct operation this depends on the caller
  75         * masking the irqs.
  76         */
  77        if (cpumask_any_and(desc->pending_mask, cpu_online_mask) < nr_cpu_ids) {
  78                int ret;
  79
  80                ret = irq_do_set_affinity(data, desc->pending_mask, false);
  81                /*
  82                 * If the there is a cleanup pending in the underlying
  83                 * vector management, reschedule the move for the next
  84                 * interrupt. Leave desc->pending_mask intact.
  85                 */
  86                if (ret == -EBUSY) {
  87                        irqd_set_move_pending(data);
  88                        return;
  89                }
  90        }
  91        cpumask_clear(desc->pending_mask);
  92}
  93
  94void __irq_move_irq(struct irq_data *idata)
  95{
  96        bool masked;
  97
  98        /*
  99         * Get top level irq_data when CONFIG_IRQ_DOMAIN_HIERARCHY is enabled,
 100         * and it should be optimized away when CONFIG_IRQ_DOMAIN_HIERARCHY is
 101         * disabled. So we avoid an "#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY" here.
 102         */
 103        idata = irq_desc_get_irq_data(irq_data_to_desc(idata));
 104
 105        if (unlikely(irqd_irq_disabled(idata)))
 106                return;
 107
 108        /*
 109         * Be careful vs. already masked interrupts. If this is a
 110         * threaded interrupt with ONESHOT set, we can end up with an
 111         * interrupt storm.
 112         */
 113        masked = irqd_irq_masked(idata);
 114        if (!masked)
 115                idata->chip->irq_mask(idata);
 116        irq_move_masked_irq(idata);
 117        if (!masked)
 118                idata->chip->irq_unmask(idata);
 119}
 120