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   1 /*
   2  *      linux/arch/x86_64/kernel/irq.c
   3  *
   4  *      Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
   5  *
   6  * This file contains the lowest level x86_64-specific interrupt
   7  * entry and irq statistics code. All the remaining irq logic is
   8  * done by the generic kernel/irq/ code and in the
   9  * x86_64-specific irq controller code. (e.g. i8259.c and
  10  * io_apic.c.)
  11  */
  12
  13 #include <linux/kernel_stat.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/seq_file.h>
  16 #include <linux/module.h>
  17 #include <linux/delay.h>
  18 #include <asm/uaccess.h>
  19 #include <asm/io_apic.h>
  20 #include <asm/idle.h>
  21
  22 atomic_t irq_err_count;
  23 #ifdef CONFIG_X86_IO_APIC
  24 #ifdef APIC_MISMATCH_DEBUG
  25 atomic_t irq_mis_count;
  26 #endif
  27 #endif
  28
  29 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  30 /*
  31  * Probabilistic stack overflow check:
  32  *
  33  * Only check the stack in process context, because everything else
  34  * runs on the big interrupt stacks. Checking reliably is too expensive,
  35  * so we just check from interrupts.
  36  */
  37 static inline void stack_overflow_check(struct pt_regs *regs)
  38 {
  39         u64 curbase = (u64) current->thread_info;
  40         static unsigned long warned = -60*HZ;
  41
  42         if (regs->rsp >= curbase && regs->rsp <= curbase + THREAD_SIZE &&
  43             regs->rsp <  curbase + sizeof(struct thread_info) + 128 &&
  44             time_after(jiffies, warned + 60*HZ)) {
  45                 printk("do_IRQ: %s near stack overflow (cur:%Lx,rsp:%lx)\n",
  46                        current->comm, curbase, regs->rsp);
  47                 show_stack(NULL,NULL);
  48                 warned = jiffies;
  49         }
  50 }
  51 #endif
  52
  53 /*
  54  * Generic, controller-independent functions:
  55  */
  56
  57 int show_interrupts(struct seq_file *p, void *v)
  58 {
  59         int i = *(loff_t *) v, j;
  60         struct irqaction * action;
  61         unsigned long flags;
  62
  63         if (i == 0) {
  64                 seq_printf(p, "           ");
  65                 for_each_online_cpu(j)
  66                         seq_printf(p, "CPU%-8d",j);
  67                 seq_putc(p, '\n');
  68         }
  69
  70         if (i < NR_IRQS) {
  71                 spin_lock_irqsave(&irq_desc[i].lock, flags);
  72                 action = irq_desc[i].action;
  73                 if (!action)
  74                         goto skip;
  75                 seq_printf(p, "%3d: ",i);
  76 #ifndef CONFIG_SMP
  77                 seq_printf(p, "%10u ", kstat_irqs(i));
  78 #else
  79                 for_each_online_cpu(j)
  80                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
  81 #endif
  82                 seq_printf(p, " %14s", irq_desc[i].chip->typename);
  83
  84                 seq_printf(p, "  %s", action->name);
  85                 for (action=action->next; action; action = action->next)
  86                         seq_printf(p, ", %s", action->name);
  87                 seq_putc(p, '\n');
  88 skip:
  89                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
  90         } else if (i == NR_IRQS) {
  91                 seq_printf(p, "NMI: ");
  92                 for_each_online_cpu(j)
  93                         seq_printf(p, "%10u ", cpu_pda(j)->__nmi_count);
  94                 seq_putc(p, '\n');
  95 #ifdef CONFIG_X86_LOCAL_APIC
  96                 seq_printf(p, "LOC: ");
  97                 for_each_online_cpu(j)
  98                         seq_printf(p, "%10u ", cpu_pda(j)->apic_timer_irqs);
  99                 seq_putc(p, '\n');
 100 #endif
 101                 seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
 102 #ifdef CONFIG_X86_IO_APIC
 103 #ifdef APIC_MISMATCH_DEBUG
 104                 seq_printf(p, "MIS: %10u\n", atomic_read(&irq_mis_count));
 105 #endif
 106 #endif
 107         }
 108         return 0;
 109 }
 110
 111 /*
 112  * do_IRQ handles all normal device IRQ's (the special
 113  * SMP cross-CPU interrupts have their own specific
 114  * handlers).
 115  */
 116 asmlinkage unsigned int do_IRQ(struct pt_regs *regs)
 117 {
 118         /* high bit used in ret_from_ code  */
 119         unsigned irq = ~regs->orig_rax;
 120
 121         if (unlikely(irq >= NR_IRQS)) {
 122                 printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
 123                                         __FUNCTION__, irq);
 124                 BUG();
 125         }
 126
 127         exit_idle();
 128         irq_enter();
 129 #ifdef CONFIG_DEBUG_STACKOVERFLOW
 130         stack_overflow_check(regs);
 131 #endif
 132         __do_IRQ(irq, regs);
 133         irq_exit();
 134
 135         return 1;
 136 }
 137
 138 #ifdef CONFIG_HOTPLUG_CPU
 139 void fixup_irqs(cpumask_t map)
 140 {
 141         unsigned int irq;
 142         static int warned;
 143
 144         for (irq = 0; irq < NR_IRQS; irq++) {
 145                 cpumask_t mask;
 146                 if (irq == 2)
 147                         continue;
 148
 149                 cpus_and(mask, irq_desc[irq].affinity, map);
 150                 if (any_online_cpu(mask) == NR_CPUS) {
 151                         printk("Breaking affinity for irq %i\n", irq);
 152                         mask = map;
 153                 }
 154                 if (irq_desc[irq].chip->set_affinity)
 155                         irq_desc[irq].chip->set_affinity(irq, mask);
 156                 else if (irq_desc[irq].action && !(warned++))
 157                         printk("Cannot set affinity for irq %i\n", irq);
 158         }
 159
 160         /* That doesn't seem sufficient.  Give it 1ms. */
 161         local_irq_enable();
 162         mdelay(1);
 163         local_irq_disable();
 164 }
 165 #endif
 166
 167 extern void call_softirq(void);
 168
 169 asmlinkage void do_softirq(void)
 170 {
 171         __u32 pending;
 172         unsigned long flags;
 173
 174         if (in_interrupt())
 175                 return;
 176
 177         local_irq_save(flags);
 178         pending = local_softirq_pending();
 179         /* Switch to interrupt stack */
 180         if (pending) {
 181                 call_softirq();
 182                 WARN_ON_ONCE(softirq_count());
 183         }
 184         local_irq_restore(flags);
 185 }
 186 EXPORT_SYMBOL(do_softirq);