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 <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
  23 int 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  */
  32 static 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
  71 bool handle_irq(unsigned irq, struct pt_regs *regs)
  72 {
  73         struct irq_desc *desc;
  74
  75         stack_overflow_check(regs);
  76
  77         desc = irq_to_desc(irq);
  78         if (unlikely(!desc))
  79                 return false;
  80
  81         generic_handle_irq_desc(irq, desc);
  82         return true;
  83 }