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 #include <asm/apic.h>
  22
  23 DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
  24 EXPORT_PER_CPU_SYMBOL(irq_stat);
  25
  26 DEFINE_PER_CPU(struct pt_regs *, irq_regs);
  27 EXPORT_PER_CPU_SYMBOL(irq_regs);
  28
  29 /*
  30  * Probabilistic stack overflow check:
  31  *
  32  * Only check the stack in process context, because everything else
  33  * runs on the big interrupt stacks. Checking reliably is too expensive,
  34  * so we just check from interrupts.
  35  */
  36 static inline void stack_overflow_check(struct pt_regs *regs)
  37 {
  38 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  39         u64 curbase = (u64)task_stack_page(current);
  40
  41         WARN_ONCE(regs->sp >= curbase &&
  42                   regs->sp <= curbase + THREAD_SIZE &&
  43                   regs->sp <  curbase + sizeof(struct thread_info) +
  44                                         sizeof(struct pt_regs) + 128,
  45
  46                   "do_IRQ: %s near stack overflow (cur:%Lx,sp:%lx)\n",
  47                         current->comm, curbase, regs->sp);
  48 #endif
  49 }
  50
  51 /*
  52  * do_IRQ handles all normal device IRQ's (the special
  53  * SMP cross-CPU interrupts have their own specific
  54  * handlers).
  55  */
  56 asmlinkage unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
  57 {
  58         struct pt_regs *old_regs = set_irq_regs(regs);
  59         struct irq_desc *desc;
  60
  61         /* high bit used in ret_from_ code  */
  62         unsigned vector = ~regs->orig_ax;
  63         unsigned irq;
  64
  65         exit_idle();
  66         irq_enter();
  67         irq = __get_cpu_var(vector_irq)[vector];
  68
  69         stack_overflow_check(regs);
  70
  71         desc = irq_to_desc(irq);
  72         if (likely(desc))
  73                 generic_handle_irq_desc(irq, desc);
  74         else {
  75                 if (!disable_apic)
  76                         ack_APIC_irq();
  77
  78                 if (printk_ratelimit())
  79                         printk(KERN_EMERG "%s: %d.%d No irq handler for vector\n",
  80                                 __func__, smp_processor_id(), vector);
  81         }
  82
  83         irq_exit();
  84
  85         set_irq_regs(old_regs);
  86         return 1;
  87 }
  88
  89 #ifdef CONFIG_HOTPLUG_CPU
  90 /* A cpu has been removed from cpu_online_mask.  Reset irq affinities. */
  91 void fixup_irqs(void)
  92 {
  93         unsigned int irq;
  94         static int warned;
  95         struct irq_desc *desc;
  96
  97         for_each_irq_desc(irq, desc) {
  98                 int break_affinity = 0;
  99                 int set_affinity = 1;
 100                 const struct cpumask *affinity;
 101
 102                 if (!desc)
 103                         continue;
 104                 if (irq == 2)
 105                         continue;
 106
 107                 /* interrupt's are disabled at this point */
 108                 spin_lock(&desc->lock);
 109
 110                 affinity = desc->affinity;
 111                 if (!irq_has_action(irq) ||
 112                     cpumask_equal(affinity, cpu_online_mask)) {
 113                         spin_unlock(&desc->lock);
 114                         continue;
 115                 }
 116
 117                 if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
 118                         break_affinity = 1;
 119                         affinity = cpu_all_mask;
 120                 }
 121
 122                 if (desc->chip->mask)
 123                         desc->chip->mask(irq);
 124
 125                 if (desc->chip->set_affinity)
 126                         desc->chip->set_affinity(irq, affinity);
 127                 else if (!(warned++))
 128                         set_affinity = 0;
 129
 130                 if (desc->chip->unmask)
 131                         desc->chip->unmask(irq);
 132
 133                 spin_unlock(&desc->lock);
 134
 135                 if (break_affinity && set_affinity)
 136                         printk("Broke affinity for irq %i\n", irq);
 137                 else if (!set_affinity)
 138                         printk("Cannot set affinity for irq %i\n", irq);
 139         }
 140
 141         /* That doesn't seem sufficient.  Give it 1ms. */
 142         local_irq_enable();
 143         mdelay(1);
 144         local_irq_disable();
 145 }
 146 #endif
 147
 148 extern void call_softirq(void);
 149
 150 asmlinkage void do_softirq(void)
 151 {
 152         __u32 pending;
 153         unsigned long flags;
 154
 155         if (in_interrupt())
 156                 return;
 157
 158         local_irq_save(flags);
 159         pending = local_softirq_pending();
 160         /* Switch to interrupt stack */
 161         if (pending) {
 162                 call_softirq();
 163                 WARN_ON_ONCE(softirq_count());
 164         }
 165         local_irq_restore(flags);
 166 }