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 DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
  24 EXPORT_PER_CPU_SYMBOL(irq_stat);
  25
  26 DEFINE_PER_CPU(struct pt_regs *, irq_regs);
  27 EXPORT_PER_CPU_SYMBOL(irq_regs);
  28
  29 int sysctl_panic_on_stackoverflow;
  30
  31 /*
  32  * Probabilistic stack overflow check:
  33  *
  34  * Only check the stack in process context, because everything else
  35  * runs on the big interrupt stacks. Checking reliably is too expensive,
  36  * so we just check from interrupts.
  37  */
  38 static inline void stack_overflow_check(struct pt_regs *regs)
  39 {
  40 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  41 #define STACK_TOP_MARGIN        128
  42         struct orig_ist *oist;
  43         u64 irq_stack_top, irq_stack_bottom;
  44         u64 estack_top, estack_bottom;
  45         u64 curbase = (u64)task_stack_page(current);
  46
  47         if (user_mode_vm(regs))
  48                 return;
  49
  50         if (regs->sp >= curbase + sizeof(struct thread_info) +
  51                                   sizeof(struct pt_regs) + STACK_TOP_MARGIN &&
  52             regs->sp <= curbase + THREAD_SIZE)
  53                 return;
  54
  55         irq_stack_top = (u64)__get_cpu_var(irq_stack_union.irq_stack) +
  56                         STACK_TOP_MARGIN;
  57         irq_stack_bottom = (u64)__get_cpu_var(irq_stack_ptr);
  58         if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom)
  59                 return;
  60
  61         oist = &__get_cpu_var(orig_ist);
  62         estack_top = (u64)oist->ist[0] - EXCEPTION_STKSZ + STACK_TOP_MARGIN;
  63         estack_bottom = (u64)oist->ist[N_EXCEPTION_STACKS - 1];
  64         if (regs->sp >= estack_top && regs->sp <= estack_bottom)
  65                 return;
  66
  67         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",
  68                 current->comm, curbase, regs->sp,
  69                 irq_stack_top, irq_stack_bottom,
  70                 estack_top, estack_bottom);
  71
  72         if (sysctl_panic_on_stackoverflow)
  73                 panic("low stack detected by irq handler - check messages\n");
  74 #endif
  75 }
  76
  77 bool handle_irq(unsigned irq, struct pt_regs *regs)
  78 {
  79         struct irq_desc *desc;
  80
  81         stack_overflow_check(regs);
  82
  83         desc = irq_to_desc(irq);
  84         if (unlikely(!desc))
  85                 return false;
  86
  87         generic_handle_irq_desc(irq, desc);
  88         return true;
  89 }
  90
  91
  92 extern void call_softirq(void);
  93
  94 asmlinkage void do_softirq(void)
  95 {
  96         __u32 pending;
  97         unsigned long flags;
  98
  99         if (in_interrupt())
 100                 return;
 101
 102         local_irq_save(flags);
 103         pending = local_softirq_pending();
 104         /* Switch to interrupt stack */
 105         if (pending) {
 106                 call_softirq();
 107                 WARN_ON_ONCE(softirq_count());
 108         }
 109         local_irq_restore(flags);
 110 }