kernel/irq/migration.c

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