kernel/irq/migration.c

0001 // SPDX-License-Identifier: GPL-2.0
0002
0003 #include <linux/irq.h>
0004 #include <linux/interrupt.h>
0005
0006 #include "internals.h"
0007
0008 /**
0009  * irq_fixup_move_pending - Cleanup irq move pending from a dying CPU
0010  * @desc:       Interrupt descriptor to clean up
0011  * @force_clear:    If set clear the move pending bit unconditionally.
0012  *          If not set, clear it only when the dying CPU is the
0013  *          last one in the pending mask.
0014  *
0015  * Returns true if the pending bit was set and the pending mask contains an
0016  * online CPU other than the dying CPU.
0017  */
0018 bool irq_fixup_move_pending(struct irq_desc *desc, bool force_clear)
0019 {
0020     struct irq_data *data = irq_desc_get_irq_data(desc);
0021
0022     if (!irqd_is_setaffinity_pending(data))
0023         return false;
0024
0025     /*
0026      * The outgoing CPU might be the last online target in a pending
0027      * interrupt move. If that's the case clear the pending move bit.
0028      */
0029     if (cpumask_any_and(desc->pending_mask, cpu_online_mask) >= nr_cpu_ids) {
0030         irqd_clr_move_pending(data);
0031         return false;
0032     }
0033     if (force_clear)
0034         irqd_clr_move_pending(data);
0035     return true;
0036 }
0037
0038 void irq_move_masked_irq(struct irq_data *idata)
0039 {
0040     struct irq_desc *desc = irq_data_to_desc(idata);
0041     struct irq_data *data = &desc->irq_data;
0042     struct irq_chip *chip = data->chip;
0043
0044     if (likely(!irqd_is_setaffinity_pending(data)))
0045         return;
0046
0047     irqd_clr_move_pending(data);
0048
0049     /*
0050      * Paranoia: cpu-local interrupts shouldn't be calling in here anyway.
0051      */
0052     if (irqd_is_per_cpu(data)) {
0053         WARN_ON(1);
0054         return;
0055     }
0056
0057     if (unlikely(cpumask_empty(desc->pending_mask)))
0058         return;
0059
0060     if (!chip->irq_set_affinity)
0061         return;
0062
0063     assert_raw_spin_locked(&desc->lock);
0064
0065     /*
0066      * If there was a valid mask to work with, please
0067      * do the disable, re-program, enable sequence.
0068      * This is *not* particularly important for level triggered
0069      * but in a edge trigger case, we might be setting rte
0070      * when an active trigger is coming in. This could
0071      * cause some ioapics to mal-function.
0072      * Being paranoid i guess!
0073      *
0074      * For correct operation this depends on the caller
0075      * masking the irqs.
0076      */
0077     if (cpumask_any_and(desc->pending_mask, cpu_online_mask) < nr_cpu_ids) {
0078         int ret;
0079
0080         ret = irq_do_set_affinity(data, desc->pending_mask, false);
0081         /*
0082          * If the there is a cleanup pending in the underlying
0083          * vector management, reschedule the move for the next
0084          * interrupt. Leave desc->pending_mask intact.
0085          */
0086         if (ret == -EBUSY) {
0087             irqd_set_move_pending(data);
0088             return;
0089         }
0090     }
0091     cpumask_clear(desc->pending_mask);
0092 }
0093
0094 void __irq_move_irq(struct irq_data *idata)
0095 {
0096     bool masked;
0097
0098     /*
0099      * Get top level irq_data when CONFIG_IRQ_DOMAIN_HIERARCHY is enabled,
0100      * and it should be optimized away when CONFIG_IRQ_DOMAIN_HIERARCHY is
0101      * disabled. So we avoid an "#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY" here.
0102      */
0103     idata = irq_desc_get_irq_data(irq_data_to_desc(idata));
0104
0105     if (unlikely(irqd_irq_disabled(idata)))
0106         return;
0107
0108     /*
0109      * Be careful vs. already masked interrupts. If this is a
0110      * threaded interrupt with ONESHOT set, we can end up with an
0111      * interrupt storm.
0112      */
0113     masked = irqd_irq_masked(idata);
0114     if (!masked)
0115         idata->chip->irq_mask(idata);
0116     irq_move_masked_irq(idata);
0117     if (!masked)
0118         idata->chip->irq_unmask(idata);
0119 }