LXR linux/arch/x86/kernel/irq

   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
  23DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
  24EXPORT_PER_CPU_SYMBOL(irq_stat);
  25
  26DEFINE_PER_CPU(struct pt_regs *, irq_regs);
  27EXPORT_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 */
  36static 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
  51bool handle_irq(unsigned irq, struct pt_regs *regs)
  52{
  53        struct irq_desc *desc;
  54
  55        stack_overflow_check(regs);
  56
  57        desc = irq_to_desc(irq);
  58        if (unlikely(!desc))
  59                return false;
  60
  61        generic_handle_irq_desc(irq, desc);
  62        return true;
  63}
  64
  65#ifdef CONFIG_HOTPLUG_CPU
  66/* A cpu has been removed from cpu_online_mask.  Reset irq affinities. */
  67void fixup_irqs(void)
  68{
  69        unsigned int irq;
  70        static int warned;
  71        struct irq_desc *desc;
  72
  73        for_each_irq_desc(irq, desc) {
  74                int break_affinity = 0;
  75                int set_affinity = 1;
  76                const struct cpumask *affinity;
  77
  78                if (!desc)
  79                        continue;
  80                if (irq == 2)
  81                        continue;
  82
  83                /* interrupt's are disabled at this point */
  84                spin_lock(&desc->lock);
  85
  86                affinity = desc->affinity;
  87                if (!irq_has_action(irq) ||
  88                    cpumask_equal(affinity, cpu_online_mask)) {
  89                        spin_unlock(&desc->lock);
  90                        continue;
  91                }
  92
  93                if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
  94                        break_affinity = 1;
  95                        affinity = cpu_all_mask;
  96                }
  97
  98                if (desc->chip->mask)
  99                        desc->chip->mask(irq);
 100
 101                if (desc->chip->set_affinity)
 102                        desc->chip->set_affinity(irq, affinity);
 103                else if (!(warned++))
 104                        set_affinity = 0;
 105
 106                if (desc->chip->unmask)
 107                        desc->chip->unmask(irq);
 108
 109                spin_unlock(&desc->lock);
 110
 111                if (break_affinity && set_affinity)
 112                        printk("Broke affinity for irq %i\n", irq);
 113                else if (!set_affinity)
 114                        printk("Cannot set affinity for irq %i\n", irq);
 115        }
 116
 117        /* That doesn't seem sufficient.  Give it 1ms. */
 118        local_irq_enable();
 119        mdelay(1);
 120        local_irq_disable();
 121}
 122#endif
 123
 124extern void call_softirq(void);
 125
 126asmlinkage void do_softirq(void)
 127{
 128        __u32 pending;
 129        unsigned long flags;
 130
 131        if (in_interrupt())
 132                return;
 133
 134        local_irq_save(flags);
 135        pending = local_softirq_pending();
 136        /* Switch to interrupt stack */
 137        if (pending) {
 138                call_softirq();
 139                WARN_ON_ONCE(softirq_count());
 140        }
 141        local_irq_restore(flags);
 142}
 143