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   1 /*
   2  *      linux/arch/alpha/kernel/irq.c
   3  *
   4  *      Copyright (C) 1995 Linus Torvalds
   5  *
   6  * This file contains the code used by various IRQ handling routines:
   7  * asking for different IRQ's should be done through these routines
   8  * instead of just grabbing them. Thus setups with different IRQ numbers
   9  * shouldn't result in any weird surprises, and installing new handlers
  10  * should be easier.
  11  */
  12
  13 #include <linux/config.h>
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/errno.h>
  17 #include <linux/kernel_stat.h>
  18 #include <linux/signal.h>
  19 #include <linux/sched.h>
  20 #include <linux/ptrace.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/slab.h>
  23 #include <linux/random.h>
  24 #include <linux/init.h>
  25 #include <linux/irq.h>
  26 #include <linux/proc_fs.h>
  27 #include <linux/seq_file.h>
  28 #include <linux/profile.h>
  29 #include <linux/bitops.h>
  30
  31 #include <asm/system.h>
  32 #include <asm/io.h>
  33 #include <asm/uaccess.h>
  34
  35 volatile unsigned long irq_err_count;
  36
  37 void ack_bad_irq(unsigned int irq)
  38 {
  39         irq_err_count++;
  40         printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq);
  41 }
  42
  43 #ifdef CONFIG_SMP
  44 static char irq_user_affinity[NR_IRQS];
  45
  46 int
  47 select_smp_affinity(unsigned int irq)
  48 {
  49         static int last_cpu;
  50         int cpu = last_cpu + 1;
  51
  52         if (!irq_desc[irq].handler->set_affinity || irq_user_affinity[irq])
  53                 return 1;
  54
  55         while (!cpu_possible(cpu))
  56                 cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
  57         last_cpu = cpu;
  58
  59         irq_affinity[irq] = cpumask_of_cpu(cpu);
  60         irq_desc[irq].handler->set_affinity(irq, cpumask_of_cpu(cpu));
  61         return 0;
  62 }
  63 #endif /* CONFIG_SMP */
  64
  65 int
  66 show_interrupts(struct seq_file *p, void *v)
  67 {
  68 #ifdef CONFIG_SMP
  69         int j;
  70 #endif
  71         int i = *(loff_t *) v;
  72         struct irqaction * action;
  73         unsigned long flags;
  74
  75 #ifdef CONFIG_SMP
  76         if (i == 0) {
  77                 seq_puts(p, "           ");
  78                 for (i = 0; i < NR_CPUS; i++)
  79                         if (cpu_online(i))
  80                                 seq_printf(p, "CPU%d       ", i);
  81                 seq_putc(p, '\n');
  82         }
  83 #endif
  84
  85         if (i < ACTUAL_NR_IRQS) {
  86                 spin_lock_irqsave(&irq_desc[i].lock, flags);
  87                 action = irq_desc[i].action;
  88                 if (!action)
  89                         goto unlock;
  90                 seq_printf(p, "%3d: ",i);
  91 #ifndef CONFIG_SMP
  92                 seq_printf(p, "%10u ", kstat_irqs(i));
  93 #else
  94                 for (j = 0; j < NR_CPUS; j++)
  95                         if (cpu_online(j))
  96                                 seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
  97 #endif
  98                 seq_printf(p, " %14s", irq_desc[i].handler->typename);
  99                 seq_printf(p, "  %c%s",
 100                         (action->flags & SA_INTERRUPT)?'+':' ',
 101                         action->name);
 102
 103                 for (action=action->next; action; action = action->next) {
 104                         seq_printf(p, ", %c%s",
 105                                   (action->flags & SA_INTERRUPT)?'+':' ',
 106                                    action->name);
 107                 }
 108
 109                 seq_putc(p, '\n');
 110 unlock:
 111                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
 112         } else if (i == ACTUAL_NR_IRQS) {
 113 #ifdef CONFIG_SMP
 114                 seq_puts(p, "IPI: ");
 115                 for (i = 0; i < NR_CPUS; i++)
 116                         if (cpu_online(i))
 117                                 seq_printf(p, "%10lu ", cpu_data[i].ipi_count);
 118                 seq_putc(p, '\n');
 119 #endif
 120                 seq_printf(p, "ERR: %10lu\n", irq_err_count);
 121         }
 122         return 0;
 123 }
 124
 125
 126 /*
 127  * handle_irq handles all normal device IRQ's (the special
 128  * SMP cross-CPU interrupts have their own specific
 129  * handlers).
 130  */
 131
 132 #define MAX_ILLEGAL_IRQS 16
 133
 134 void
 135 handle_irq(int irq, struct pt_regs * regs)
 136 {
 137         /*
 138          * We ack quickly, we don't want the irq controller
 139          * thinking we're snobs just because some other CPU has
 140          * disabled global interrupts (we have already done the
 141          * INT_ACK cycles, it's too late to try to pretend to the
 142          * controller that we aren't taking the interrupt).
 143          *
 144          * 0 return value means that this irq is already being
 145          * handled by some other CPU. (or is disabled)
 146          */
 147         static unsigned int illegal_count=0;
 148
 149         if ((unsigned) irq > ACTUAL_NR_IRQS && illegal_count < MAX_ILLEGAL_IRQS ) {
 150                 irq_err_count++;
 151                 illegal_count++;
 152                 printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n",
 153                        irq);
 154                 return;
 155         }
 156
 157         irq_enter();
 158         local_irq_disable();
 159         __do_IRQ(irq, regs);
 160         local_irq_enable();
 161         irq_exit();
 162 }