git.oblomov.eu Git - linux-2.6/blob - 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 <linux/ftrace.h>
  17 #include <linux/uaccess.h>
  18 #include <linux/smp.h>
  19 #include <asm/io_apic.h>
  20 #include <asm/idle.h>
  21
  22 /*
  23  * Probabilistic stack overflow check:
  24  *
  25  * Only check the stack in process context, because everything else
  26  * runs on the big interrupt stacks. Checking reliably is too expensive,
  27  * so we just check from interrupts.
  28  */
  29 static inline void stack_overflow_check(struct pt_regs *regs)
  30 {
  31 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  32         u64 curbase = (u64)task_stack_page(current);
  33
  34         WARN_ONCE(regs->sp >= curbase &&
  35                   regs->sp <= curbase + THREAD_SIZE &&
  36                   regs->sp <  curbase + sizeof(struct thread_info) +
  37                                         sizeof(struct pt_regs) + 128,
  38
  39                   "do_IRQ: %s near stack overflow (cur:%Lx,sp:%lx)\n",
  40                         current->comm, curbase, regs->sp);
  41 #endif
  42 }
  43
  44 /*
  45  * do_IRQ handles all normal device IRQ's (the special
  46  * SMP cross-CPU interrupts have their own specific
  47  * handlers).
  48  */
  49 asmlinkage unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
  50 {
  51         struct pt_regs *old_regs = set_irq_regs(regs);
  52         struct irq_desc *desc;
  53
  54         /* high bit used in ret_from_ code  */
  55         unsigned vector = ~regs->orig_ax;
  56         unsigned irq;
  57
  58         exit_idle();
  59         irq_enter();
  60         irq = __get_cpu_var(vector_irq)[vector];
  61
  62         stack_overflow_check(regs);
  63
  64         desc = irq_to_desc(irq);
  65         if (likely(desc))
  66                 generic_handle_irq_desc(irq, desc);
  67         else {
  68                 if (!disable_apic)
  69                         ack_APIC_irq();
  70
  71                 if (printk_ratelimit())
  72                         printk(KERN_EMERG "%s: %d.%d No irq handler for vector\n",
  73                                 __func__, smp_processor_id(), vector);
  74         }
  75
  76         irq_exit();
  77
  78         set_irq_regs(old_regs);
  79         return 1;
  80 }
  81
  82 #ifdef CONFIG_HOTPLUG_CPU
  83 /* A cpu has been removed from cpu_online_mask.  Reset irq affinities. */
  84 void fixup_irqs(void)
  85 {
  86         unsigned int irq;
  87         static int warned;
  88         struct irq_desc *desc;
  89
  90         for_each_irq_desc(irq, desc) {
  91                 int break_affinity = 0;
  92                 int set_affinity = 1;
  93                 const struct cpumask *affinity;
  94
  95                 if (!desc)
  96                         continue;
  97                 if (irq == 2)
  98                         continue;
  99
 100                 /* interrupt's are disabled at this point */
 101                 spin_lock(&desc->lock);
 102
 103                 affinity = &desc->affinity;
 104                 if (!irq_has_action(irq) ||
 105                     cpumask_equal(affinity, cpu_online_mask)) {
 106                         spin_unlock(&desc->lock);
 107                         continue;
 108                 }
 109
 110                 if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
 111                         break_affinity = 1;
 112                         affinity = cpu_all_mask;
 113                 }
 114
 115                 if (desc->chip->mask)
 116                         desc->chip->mask(irq);
 117
 118                 if (desc->chip->set_affinity)
 119                         desc->chip->set_affinity(irq, affinity);
 120                 else if (!(warned++))
 121                         set_affinity = 0;
 122
 123                 if (desc->chip->unmask)
 124                         desc->chip->unmask(irq);
 125
 126                 spin_unlock(&desc->lock);
 127
 128                 if (break_affinity && set_affinity)
 129                         printk("Broke affinity for irq %i\n", irq);
 130                 else if (!set_affinity)
 131                         printk("Cannot set affinity for irq %i\n", irq);
 132         }
 133
 134         /* That doesn't seem sufficient.  Give it 1ms. */
 135         local_irq_enable();
 136         mdelay(1);
 137         local_irq_disable();
 138 }
 139 #endif
 140
 141 extern void call_softirq(void);
 142
 143 asmlinkage void do_softirq(void)
 144 {
 145         __u32 pending;
 146         unsigned long flags;
 147
 148         if (in_interrupt())
 149                 return;
 150
 151         local_irq_save(flags);
 152         pending = local_softirq_pending();
 153         /* Switch to interrupt stack */
 154         if (pending) {
 155                 call_softirq();
 156                 WARN_ON_ONCE(softirq_count());
 157         }
 158         local_irq_restore(flags);
 159 }