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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].chip->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_desc[irq].affinity = cpumask_of_cpu(cpu);
  60         irq_desc[irq].chip->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 irq = *(loff_t *) v;
  72         struct irqaction * action;
  73         unsigned long flags;
  74
  75 #ifdef CONFIG_SMP
  76         if (irq == 0) {
  77                 seq_puts(p, "           ");
  78                 for_each_online_cpu(j)
  79                         seq_printf(p, "CPU%d       ", j);
  80                 seq_putc(p, '\n');
  81         }
  82 #endif
  83
  84         if (irq < ACTUAL_NR_IRQS) {
  85                 spin_lock_irqsave(&irq_desc[irq].lock, flags);
  86                 action = irq_desc[irq].action;
  87                 if (!action)
  88                         goto unlock;
  89                 seq_printf(p, "%3d: ", irq);
  90 #ifndef CONFIG_SMP
  91                 seq_printf(p, "%10u ", kstat_irqs(irq));
  92 #else
  93                 for_each_online_cpu(j)
  94                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[irq]);
  95 #endif
  96                 seq_printf(p, " %14s", irq_desc[irq].chip->typename);
  97                 seq_printf(p, "  %c%s",
  98                         (action->flags & SA_INTERRUPT)?'+':' ',
  99                         action->name);
 100
 101                 for (action=action->next; action; action = action->next) {
 102                         seq_printf(p, ", %c%s",
 103                                   (action->flags & SA_INTERRUPT)?'+':' ',
 104                                    action->name);
 105                 }
 106
 107                 seq_putc(p, '\n');
 108 unlock:
 109                 spin_unlock_irqrestore(&irq_desc[irq].lock, flags);
 110         } else if (irq == ACTUAL_NR_IRQS) {
 111 #ifdef CONFIG_SMP
 112                 seq_puts(p, "IPI: ");
 113                 for_each_online_cpu(j)
 114                         seq_printf(p, "%10lu ", cpu_data[j].ipi_count);
 115                 seq_putc(p, '\n');
 116 #endif
 117                 seq_printf(p, "ERR: %10lu\n", irq_err_count);
 118         }
 119         return 0;
 120 }
 121
 122 /*
 123  * handle_irq handles all normal device IRQ's (the special
 124  * SMP cross-CPU interrupts have their own specific
 125  * handlers).
 126  */
 127
 128 #define MAX_ILLEGAL_IRQS 16
 129
 130 void
 131 handle_irq(int irq, struct pt_regs * regs)
 132 {
 133         /*
 134          * We ack quickly, we don't want the irq controller
 135          * thinking we're snobs just because some other CPU has
 136          * disabled global interrupts (we have already done the
 137          * INT_ACK cycles, it's too late to try to pretend to the
 138          * controller that we aren't taking the interrupt).
 139          *
 140          * 0 return value means that this irq is already being
 141          * handled by some other CPU. (or is disabled)
 142          */
 143         static unsigned int illegal_count=0;
 144
 145         if ((unsigned) irq > ACTUAL_NR_IRQS && illegal_count < MAX_ILLEGAL_IRQS ) {
 146                 irq_err_count++;
 147                 illegal_count++;
 148                 printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n",
 149                        irq);
 150                 return;
 151         }
 152
 153         irq_enter();
 154         /*
 155          * __do_IRQ() must be called with IPL_MAX. Note that we do not
 156          * explicitly enable interrupts afterwards - some MILO PALcode
 157          * (namely LX164 one) seems to have severe problems with RTI
 158          * at IPL 0.
 159          */
 160         local_irq_disable();
 161         __do_IRQ(irq, regs);
 162         irq_exit();
 163 }