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/delay.h>
  15#include <linux/ftrace.h>
  16#include <linux/uaccess.h>
  17#include <linux/smp.h>
  18#include <linux/sched/task_stack.h>
  19#include <asm/io_apic.h>
  20#include <asm/apic.h>
  21
  22int sysctl_panic_on_stackoverflow;
  23
  24/*
  25 * Probabilistic stack overflow check:
  26 *
  27 * Only check the stack in process context, because everything else
  28 * runs on the big interrupt stacks. Checking reliably is too expensive,
  29 * so we just check from interrupts.
  30 */
  31static inline void stack_overflow_check(struct pt_regs *regs)
  32{
  33#ifdef CONFIG_DEBUG_STACKOVERFLOW
  34#define STACK_TOP_MARGIN        128
  35        struct orig_ist *oist;
  36        u64 irq_stack_top, irq_stack_bottom;
  37        u64 estack_top, estack_bottom;
  38        u64 curbase = (u64)task_stack_page(current);
  39
  40        if (user_mode(regs))
  41                return;
  42
  43        if (regs->sp >= curbase + sizeof(struct pt_regs) + STACK_TOP_MARGIN &&
  44            regs->sp <= curbase + THREAD_SIZE)
  45                return;
  46
  47        irq_stack_top = (u64)this_cpu_ptr(irq_stack_union.irq_stack) +
  48                        STACK_TOP_MARGIN;
  49        irq_stack_bottom = (u64)__this_cpu_read(irq_stack_ptr);
  50        if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom)
  51                return;
  52
  53        oist = this_cpu_ptr(&orig_ist);
  54        estack_top = (u64)oist->ist[0] - EXCEPTION_STKSZ + STACK_TOP_MARGIN;
  55        estack_bottom = (u64)oist->ist[N_EXCEPTION_STACKS - 1];
  56        if (regs->sp >= estack_top && regs->sp <= estack_bottom)
  57                return;
  58
  59        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",
  60                current->comm, curbase, regs->sp,
  61                irq_stack_top, irq_stack_bottom,
  62                estack_top, estack_bottom);
  63
  64        if (sysctl_panic_on_stackoverflow)
  65                panic("low stack detected by irq handler - check messages\n");
  66#endif
  67}
  68
  69bool handle_irq(struct irq_desc *desc, struct pt_regs *regs)
  70{
  71        stack_overflow_check(regs);
  72
  73        if (IS_ERR_OR_NULL(desc))
  74                return false;
  75
  76        generic_handle_irq_desc(desc);
  77        return true;
  78}
  79