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 * Regular device interrupts can enter on the following stacks:
29 *
30 * - User stack
31 *
32 * - Kernel task stack
33 *
34 * - Interrupt stack if a device driver reenables interrupts
35 * which should only happen in really old drivers.
36 *
37 * - Debug IST stack
38 *
39 * All other contexts are invalid.
40 */
stack_overflow_check(struct pt_regs * regs)41 static inline void stack_overflow_check(struct pt_regs *regs)
42 {
43 #ifdef CONFIG_DEBUG_STACKOVERFLOW
44 #define STACK_TOP_MARGIN 128
45 struct orig_ist *oist;
46 u64 irq_stack_top, irq_stack_bottom;
47 u64 estack_top, estack_bottom;
48 u64 curbase = (u64)task_stack_page(current);
49
50 if (user_mode(regs))
51 return;
52
53 if (regs->sp >= curbase + sizeof(struct thread_info) +
54 sizeof(struct pt_regs) + STACK_TOP_MARGIN &&
55 regs->sp <= curbase + THREAD_SIZE)
56 return;
57
58 irq_stack_top = (u64)this_cpu_ptr(irq_stack_union.irq_stack) +
59 STACK_TOP_MARGIN;
60 irq_stack_bottom = (u64)__this_cpu_read(irq_stack_ptr);
61 if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom)
62 return;
63
64 oist = this_cpu_ptr(&orig_ist);
65 estack_bottom = (u64)oist->ist[DEBUG_STACK];
66 estack_top = estack_bottom - DEBUG_STKSZ + STACK_TOP_MARGIN;
67 if (regs->sp >= estack_top && regs->sp <= estack_bottom)
68 return;
69
70 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",
71 current->comm, curbase, regs->sp,
72 irq_stack_top, irq_stack_bottom,
73 estack_top, estack_bottom);
74
75 if (sysctl_panic_on_stackoverflow)
76 panic("low stack detected by irq handler - check messages\n");
77 #endif
78 }
79
handle_irq(struct irq_desc * desc,struct pt_regs * regs)80 bool handle_irq(struct irq_desc *desc, struct pt_regs *regs)
81 {
82 stack_overflow_check(regs);
83
84 if (IS_ERR_OR_NULL(desc))
85 return false;
86
87 generic_handle_irq_desc(desc);
88 return true;
89 }
90