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