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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/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/errno.h>
  16 #include <linux/kernel_stat.h>
  17 #include <linux/signal.h>
  18 #include <linux/sched.h>
  19 #include <linux/ptrace.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/slab.h>
  22 #include <linux/random.h>
  23 #include <linux/init.h>
  24 #include <linux/irq.h>
  25 #include <linux/proc_fs.h>
  26 #include <linux/seq_file.h>
  27 #include <linux/profile.h>
  28 #include <linux/bitops.h>
  29
  30 #include <asm/system.h>
  31 #include <asm/io.h>
  32 #include <asm/uaccess.h>
  33
  34 volatile unsigned long irq_err_count;
  35
  36 void ack_bad_irq(unsigned int irq)
  37 {
  38         irq_err_count++;
  39         printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq);
  40 }
  41
  42 #ifdef CONFIG_SMP
  43 static char irq_user_affinity[NR_IRQS];
  44
  45 int
  46 select_smp_affinity(unsigned int irq)
  47 {
  48         static int last_cpu;
  49         int cpu = last_cpu + 1;
  50
  51         if (!irq_desc[irq].chip->set_affinity || irq_user_affinity[irq])
  52                 return 1;
  53
  54         while (!cpu_possible(cpu))
  55                 cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
  56         last_cpu = cpu;
  57
  58         irq_desc[irq].affinity = cpumask_of_cpu(cpu);
  59         irq_desc[irq].chip->set_affinity(irq, cpumask_of_cpu(cpu));
  60         return 0;
  61 }
  62 #endif /* CONFIG_SMP */
  63
  64 int
  65 show_interrupts(struct seq_file *p, void *v)
  66 {
  67 #ifdef CONFIG_SMP
  68         int j;
  69 #endif
  70         int irq = *(loff_t *) v;
  71         struct irqaction * action;
  72         unsigned long flags;
  73
  74 #ifdef CONFIG_SMP
  75         if (irq == 0) {
  76                 seq_puts(p, "           ");
  77                 for_each_online_cpu(j)
  78                         seq_printf(p, "CPU%d       ", j);
  79                 seq_putc(p, '\n');
  80         }
  81 #endif
  82
  83         if (irq < ACTUAL_NR_IRQS) {
  84                 spin_lock_irqsave(&irq_desc[irq].lock, flags);
  85                 action = irq_desc[irq].action;
  86                 if (!action)
  87                         goto unlock;
  88                 seq_printf(p, "%3d: ", irq);
  89 #ifndef CONFIG_SMP
  90                 seq_printf(p, "%10u ", kstat_irqs(irq));
  91 #else
  92                 for_each_online_cpu(j)
  93                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[irq]);
  94 #endif
  95                 seq_printf(p, " %14s", irq_desc[irq].chip->typename);
  96                 seq_printf(p, "  %c%s",
  97                         (action->flags & IRQF_DISABLED)?'+':' ',
  98                         action->name);
  99
 100                 for (action=action->next; action; action = action->next) {
 101                         seq_printf(p, ", %c%s",
 102                                   (action->flags & IRQF_DISABLED)?'+':' ',
 103                                    action->name);
 104                 }
 105
 106                 seq_putc(p, '\n');
 107 unlock:
 108                 spin_unlock_irqrestore(&irq_desc[irq].lock, flags);
 109         } else if (irq == ACTUAL_NR_IRQS) {
 110 #ifdef CONFIG_SMP
 111                 seq_puts(p, "IPI: ");
 112                 for_each_online_cpu(j)
 113                         seq_printf(p, "%10lu ", cpu_data[j].ipi_count);
 114                 seq_putc(p, '\n');
 115 #endif
 116                 seq_printf(p, "ERR: %10lu\n", irq_err_count);
 117         }
 118         return 0;
 119 }
 120
 121 /*
 122  * handle_irq handles all normal device IRQ's (the special
 123  * SMP cross-CPU interrupts have their own specific
 124  * handlers).
 125  */
 126
 127 #define MAX_ILLEGAL_IRQS 16
 128
 129 void
 130 handle_irq(int irq, struct pt_regs * regs)
 131 {
 132         struct pt_regs *old_regs;
 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         old_regs = set_irq_regs(regs);
 154         irq_enter();
 155         /*
 156          * __do_IRQ() must be called with IPL_MAX. Note that we do not
 157          * explicitly enable interrupts afterwards - some MILO PALcode
 158          * (namely LX164 one) seems to have severe problems with RTI
 159          * at IPL 0.
 160          */
 161         local_irq_disable();
 162         __do_IRQ(irq);
 163         irq_exit();
 164         set_irq_regs(old_regs);
 165 }