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 <asm/uaccess.h>
  18 #include <asm/io_apic.h>
  19 #include <asm/idle.h>
  20 #include <asm/smp.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 void fixup_irqs(cpumask_t map)
  84 {
  85         unsigned int irq;
  86         static int warned;
  87         struct irq_desc *desc;
  88
  89         for_each_irq_desc(irq, desc) {
  90                 cpumask_t mask;
  91                 int break_affinity = 0;
  92                 int set_affinity = 1;
  93
  94                 if (irq == 2)
  95                         continue;
  96
  97                 /* interrupt's are disabled at this point */
  98                 spin_lock(&desc->lock);
  99
 100                 if (!irq_has_action(irq) ||
 101                     cpus_equal(desc->affinity, map)) {
 102                         spin_unlock(&desc->lock);
 103                         continue;
 104                 }
 105
 106                 cpus_and(mask, desc->affinity, map);
 107                 if (cpus_empty(mask)) {
 108                         break_affinity = 1;
 109                         mask = map;
 110                 }
 111
 112                 if (desc->chip->mask)
 113                         desc->chip->mask(irq);
 114
 115                 if (desc->chip->set_affinity)
 116                         desc->chip->set_affinity(irq, mask);
 117                 else if (!(warned++))
 118                         set_affinity = 0;
 119
 120                 if (desc->chip->unmask)
 121                         desc->chip->unmask(irq);
 122
 123                 spin_unlock(&desc->lock);
 124
 125                 if (break_affinity && set_affinity)
 126                         printk("Broke affinity for irq %i\n", irq);
 127                 else if (!set_affinity)
 128                         printk("Cannot set affinity for irq %i\n", irq);
 129         }
 130
 131         /* That doesn't seem sufficient.  Give it 1ms. */
 132         local_irq_enable();
 133         mdelay(1);
 134         local_irq_disable();
 135 }
 136 #endif
 137
 138 extern void call_softirq(void);
 139
 140 asmlinkage void do_softirq(void)
 141 {
 142         __u32 pending;
 143         unsigned long flags;
 144
 145         if (in_interrupt())
 146                 return;
 147
 148         local_irq_save(flags);
 149         pending = local_softirq_pending();
 150         /* Switch to interrupt stack */
 151         if (pending) {
 152                 call_softirq();
 153                 WARN_ON_ONCE(softirq_count());
 154         }
 155         local_irq_restore(flags);
 156 }