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   1 /*
   2  * linux/kernel/irq/handle.c
   3  *
   4  * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
   5  * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
   6  *
   7  * This file contains the core interrupt handling code.
   8  *
   9  * Detailed information is available in Documentation/DocBook/genericirq
  10  *
  11  */
  12
  13 #include <linux/irq.h>
  14 #include <linux/module.h>
  15 #include <linux/random.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/kernel_stat.h>
  18
  19 #include "internals.h"
  20
  21 static void init_copy_kstat_irqs(struct irq_desc *old_desc,
  22                                  struct irq_desc *desc,
  23                                  int cpu, int nr)
  24 {
  25         unsigned long bytes;
  26
  27         init_kstat_irqs(desc, cpu, nr);
  28
  29         if (desc->kstat_irqs != old_desc->kstat_irqs) {
  30                 /* Compute how many bytes we need per irq and allocate them */
  31                 bytes = nr * sizeof(unsigned int);
  32
  33                 memcpy(desc->kstat_irqs, old_desc->kstat_irqs, bytes);
  34         }
  35 }
  36
  37 static void free_kstat_irqs(struct irq_desc *old_desc, struct irq_desc *desc)
  38 {
  39         if (old_desc->kstat_irqs == desc->kstat_irqs)
  40                 return;
  41
  42         kfree(old_desc->kstat_irqs);
  43         old_desc->kstat_irqs = NULL;
  44 }
  45
  46 static void init_copy_one_irq_desc(int irq, struct irq_desc *old_desc,
  47                  struct irq_desc *desc, int cpu)
  48 {
  49         memcpy(desc, old_desc, sizeof(struct irq_desc));
  50         desc->cpu = cpu;
  51         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
  52         init_copy_kstat_irqs(old_desc, desc, cpu, nr_cpu_ids);
  53         arch_init_copy_chip_data(old_desc, desc, cpu);
  54 }
  55
  56 static void free_one_irq_desc(struct irq_desc *old_desc, struct irq_desc *desc)
  57 {
  58         free_kstat_irqs(old_desc, desc);
  59         arch_free_chip_data(old_desc, desc);
  60 }
  61
  62 static struct irq_desc *__real_move_irq_desc(struct irq_desc *old_desc,
  63                                                 int cpu)
  64 {
  65         struct irq_desc *desc;
  66         unsigned int irq;
  67         unsigned long flags;
  68         int node;
  69
  70         irq = old_desc->irq;
  71
  72         spin_lock_irqsave(&sparse_irq_lock, flags);
  73
  74         /* We have to check it to avoid races with another CPU */
  75         desc = irq_desc_ptrs[irq];
  76
  77         if (desc && old_desc != desc)
  78                         goto out_unlock;
  79
  80         node = cpu_to_node(cpu);
  81         desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
  82         printk(KERN_DEBUG "  move irq_desc for %d to cpu %d node %d\n",
  83                  irq, cpu, node);
  84         if (!desc) {
  85                 printk(KERN_ERR "can not get new irq_desc for moving\n");
  86                 /* still use old one */
  87                 desc = old_desc;
  88                 goto out_unlock;
  89         }
  90         init_copy_one_irq_desc(irq, old_desc, desc, cpu);
  91
  92         irq_desc_ptrs[irq] = desc;
  93
  94         /* free the old one */
  95         free_one_irq_desc(old_desc, desc);
  96         kfree(old_desc);
  97
  98 out_unlock:
  99         spin_unlock_irqrestore(&sparse_irq_lock, flags);
 100
 101         return desc;
 102 }
 103
 104 struct irq_desc *move_irq_desc(struct irq_desc *desc, int cpu)
 105 {
 106         int old_cpu;
 107         int node, old_node;
 108
 109         /* those all static, do move them */
 110         if (desc->irq < NR_IRQS_LEGACY)
 111                 return desc;
 112
 113         old_cpu = desc->cpu;
 114         printk(KERN_DEBUG
 115                  "try to move irq_desc from cpu %d to %d\n", old_cpu, cpu);
 116         if (old_cpu != cpu) {
 117                 node = cpu_to_node(cpu);
 118                 old_node = cpu_to_node(old_cpu);
 119                 if (old_node != node)
 120                         desc = __real_move_irq_desc(desc, cpu);
 121                 else
 122                         desc->cpu = cpu;
 123         }
 124
 125         return desc;
 126 }
 127