2 * Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
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
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>
23 DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
24 EXPORT_PER_CPU_SYMBOL(irq_stat);
26 DEFINE_PER_CPU(struct pt_regs *, irq_regs);
27 EXPORT_PER_CPU_SYMBOL(irq_regs);
29 int sysctl_panic_on_stackoverflow;
32 * Probabilistic stack overflow check:
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.
38 static inline void stack_overflow_check(struct pt_regs *regs)
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);
47 if (user_mode_vm(regs))
50 if (regs->sp >= curbase + sizeof(struct thread_info) +
51 sizeof(struct pt_regs) + STACK_TOP_MARGIN &&
52 regs->sp <= curbase + THREAD_SIZE)
55 irq_stack_top = (u64)__get_cpu_var(irq_stack_union.irq_stack) +
57 irq_stack_bottom = (u64)__get_cpu_var(irq_stack_ptr);
58 if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom)
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)
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);
72 if (sysctl_panic_on_stackoverflow)
73 panic("low stack detected by irq handler - check messages\n");
77 bool handle_irq(unsigned irq, struct pt_regs *regs)
79 struct irq_desc *desc;
81 stack_overflow_check(regs);
83 desc = irq_to_desc(irq);
87 generic_handle_irq_desc(irq, desc);
92 extern void call_softirq(void);
94 asmlinkage void do_softirq(void)
102 local_irq_save(flags);
103 pending = local_softirq_pending();
104 /* Switch to interrupt stack */
107 WARN_ON_ONCE(softirq_count());
109 local_irq_restore(flags);