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
  23int sysctl_panic_on_stackoverflow;
  24
  25/*
  26 * Probabilistic stack overflow check:
  27 *
  28 * Only check the stack in process context, because everything else
  29 * runs on the big interrupt stacks. Checking reliably is too expensive,
  30 * so we just check from interrupts.
  31 */
  32static inline void stack_overflow_check(struct pt_regs *regs)
  33{
  34#ifdef CONFIG_DEBUG_STACKOVERFLOW
  35#define STACK_TOP_MARGIN        128
  36        struct orig_ist *oist;
  37        u64 irq_stack_top, irq_stack_bottom;
  38        u64 estack_top, estack_bottom;
  39        u64 curbase = (u64)task_stack_page(current);
  40
  41        if (user_mode(regs))
  42                return;
  43
  44        if (regs->sp >= curbase + sizeof(struct thread_info) +
  45                                  sizeof(struct pt_regs) + STACK_TOP_MARGIN &&
  46            regs->sp <= curbase + THREAD_SIZE)
  47                return;
  48
  49        irq_stack_top = (u64)this_cpu_ptr(irq_stack_union.irq_stack) +
  50                        STACK_TOP_MARGIN;
  51        irq_stack_bottom = (u64)__this_cpu_read(irq_stack_ptr);
  52        if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom)
  53                return;
  54
  55        oist = this_cpu_ptr(&orig_ist);
  56        estack_top = (u64)oist->ist[0] - EXCEPTION_STKSZ + STACK_TOP_MARGIN;
  57        estack_bottom = (u64)oist->ist[N_EXCEPTION_STACKS - 1];
  58        if (regs->sp >= estack_top && regs->sp <= estack_bottom)
  59                return;
  60
  61        WARN_ONCE(1, "do_IRQ(): %s has overflown the kernel stack (cur:%Lx,sp:%lx,irq stk top-bottom:%Lx-%Lx,exception stk top-bottom:%Lx-%Lx)\n",
  62                current->comm, curbase, regs->sp,
  63                irq_stack_top, irq_stack_bottom,
  64                estack_top, estack_bottom);
  65
  66        if (sysctl_panic_on_stackoverflow)
  67                panic("low stack detected by irq handler - check messages\n");
  68#endif
  69}
  70
  71bool handle_irq(struct irq_desc *desc, struct pt_regs *regs)
  72{
  73        stack_overflow_check(regs);
  74
  75        if (unlikely(IS_ERR_OR_NULL(desc)))
  76                return false;
  77
  78        generic_handle_irq_desc(desc);
  79        return true;
  80}
  81