arch/x86/kernel/irq_64.c

   1 /*
   2  *      Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
   3  *
   4  * This file contains the lowest level x86_64-specific interrupt
   5  * entry and irq statistics code. All the remaining irq logic is
   6  * done by the generic kernel/irq/ code and in the
   7  * x86_64-specific irq controller code. (e.g. i8259.c and
   8  * io_apic.c.)
   9  */
  10
  11 #include <linux/kernel_stat.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/seq_file.h>
  14 #include <linux/module.h>
  15 #include <linux/delay.h>
  16 #include <asm/uaccess.h>
  17 #include <asm/io_apic.h>
  18 #include <asm/idle.h>
  19 #include <asm/smp.h>
  20
  21 /*
  22  * Probabilistic stack overflow check:
  23  *
  24  * Only check the stack in process context, because everything else
  25  * runs on the big interrupt stacks. Checking reliably is too expensive,
  26  * so we just check from interrupts.
  27  */
  28 static inline void stack_overflow_check(struct pt_regs *regs)
  29 {
  30 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  31         u64 curbase = (u64)task_stack_page(current);
  32
  33         WARN_ONCE(regs->sp >= curbase &&
  34                   regs->sp <= curbase + THREAD_SIZE &&
  35                   regs->sp <  curbase + sizeof(struct thread_info) +
  36                                         sizeof(struct pt_regs) + 128,
  37
  38                   "do_IRQ: %s near stack overflow (cur:%Lx,sp:%lx)\n",
  39                         current->comm, curbase, regs->sp);
  40 #endif
  41 }
  42
  43 /*
  44  * do_IRQ handles all normal device IRQ's (the special
  45  * SMP cross-CPU interrupts have their own specific
  46  * handlers).
  47  */
  48 asmlinkage unsigned int do_IRQ(struct pt_regs *regs)
  49 {
  50         struct pt_regs *old_regs = set_irq_regs(regs);
  51         struct irq_desc *desc;
  52
  53         /* high bit used in ret_from_ code  */
  54         unsigned vector = ~regs->orig_ax;
  55         unsigned irq;
  56
  57         exit_idle();
  58         irq_enter();
  59         irq = __get_cpu_var(vector_irq)[vector];
  60
  61         stack_overflow_check(regs);
  62
  63         desc = irq_to_desc(irq);
  64         if (likely(desc))
  65                 generic_handle_irq_desc(irq, desc);
  66         else {
  67                 if (!disable_apic)
  68                         ack_APIC_irq();
  69
  70                 if (printk_ratelimit())
  71                         printk(KERN_EMERG "%s: %d.%d No irq handler for vector\n",
  72                                 __func__, smp_processor_id(), vector);
  73         }
  74
  75         irq_exit();
  76
  77         set_irq_regs(old_regs);
  78         return 1;
  79 }
  80
  81 #ifdef CONFIG_HOTPLUG_CPU
  82 void fixup_irqs(cpumask_t map)
  83 {
  84         unsigned int irq;
  85         static int warned;
  86         struct irq_desc *desc;
  87
  88         for_each_irq_desc(irq, desc) {
  89                 cpumask_t mask;
  90                 int break_affinity = 0;
  91                 int set_affinity = 1;
  92
  93                 if (irq == 2)
  94                         continue;
  95
  96                 /* interrupt's are disabled at this point */
  97                 spin_lock(&desc->lock);
  98
  99                 if (!irq_has_action(irq) ||
 100                     cpus_equal(desc->affinity, map)) {
 101                         spin_unlock(&desc->lock);
 102                         continue;
 103                 }
 104
 105                 cpus_and(mask, desc->affinity, map);
 106                 if (cpus_empty(mask)) {
 107                         break_affinity = 1;
 108                         mask = map;
 109                 }
 110
 111                 if (desc->chip->mask)
 112                         desc->chip->mask(irq);
 113
 114                 if (desc->chip->set_affinity)
 115                         desc->chip->set_affinity(irq, mask);
 116                 else if (!(warned++))
 117                         set_affinity = 0;
 118
 119                 if (desc->chip->unmask)
 120                         desc->chip->unmask(irq);
 121
 122                 spin_unlock(&desc->lock);
 123
 124                 if (break_affinity && set_affinity)
 125                         printk("Broke affinity for irq %i\n", irq);
 126                 else if (!set_affinity)
 127                         printk("Cannot set affinity for irq %i\n", irq);
 128         }
 129
 130         /* That doesn't seem sufficient.  Give it 1ms. */
 131         local_irq_enable();
 132         mdelay(1);
 133         local_irq_disable();
 134 }
 135 #endif
 136
 137 extern void call_softirq(void);
 138
 139 asmlinkage void do_softirq(void)
 140 {
 141         __u32 pending;
 142         unsigned long flags;
 143
 144         if (in_interrupt())
 145                 return;
 146
 147         local_irq_save(flags);
 148         pending = local_softirq_pending();
 149         /* Switch to interrupt stack */
 150         if (pending) {
 151                 call_softirq();
 152                 WARN_ON_ONCE(softirq_count());
 153         }
 154         local_irq_restore(flags);
 155 }