linux/arch/x86/kernel/irq_64.c
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   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
  66extern void call_softirq(void);
  67
  68asmlinkage void do_softirq(void)
  69{
  70        __u32 pending;
  71        unsigned long flags;
  72
  73        if (in_interrupt())
  74                return;
  75
  76        local_irq_save(flags);
  77        pending = local_softirq_pending();
  78        /* Switch to interrupt stack */
  79        if (pending) {
  80                call_softirq();
  81                WARN_ON_ONCE(softirq_count());
  82        }
  83        local_irq_restore(flags);
  84}
  85