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