1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 *	Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
 4 *
 5 * This file contains the lowest level x86_64-specific interrupt
 6 * entry and irq statistics code. All the remaining irq logic is
 7 * done by the generic kernel/irq/ code and in the
 8 * x86_64-specific irq controller code. (e.g. i8259.c and
 9 * io_apic.c.)
10 */
11
12#include <linux/kernel_stat.h>
13#include <linux/interrupt.h>
14#include <linux/seq_file.h>
15#include <linux/delay.h>
16#include <linux/ftrace.h>
17#include <linux/uaccess.h>
18#include <linux/smp.h>
19#include <linux/sched/task_stack.h>
20#include <asm/io_apic.h>
21#include <asm/apic.h>
22
23int 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 */
32static 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 pt_regs) + STACK_TOP_MARGIN &&
45	    regs->sp <= curbase + THREAD_SIZE)
46		return;
47
48	irq_stack_top = (u64)this_cpu_ptr(irq_stack_union.irq_stack) +
49			STACK_TOP_MARGIN;
50	irq_stack_bottom = (u64)__this_cpu_read(irq_stack_ptr);
51	if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom)
52		return;
53
54	oist = this_cpu_ptr(&orig_ist);
55	estack_top = (u64)oist->ist[0] - EXCEPTION_STKSZ + STACK_TOP_MARGIN;
56	estack_bottom = (u64)oist->ist[N_EXCEPTION_STACKS - 1];
57	if (regs->sp >= estack_top && regs->sp <= estack_bottom)
58		return;
59
60	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,ip:%pF)\n",
61		current->comm, curbase, regs->sp,
62		irq_stack_top, irq_stack_bottom,
63		estack_top, estack_bottom, (void *)regs->ip);
64
65	if (sysctl_panic_on_stackoverflow)
66		panic("low stack detected by irq handler - check messages\n");
67#endif
68}
69
70bool handle_irq(struct irq_desc *desc, struct pt_regs *regs)
71{
72	stack_overflow_check(regs);
73
74	if (IS_ERR_OR_NULL(desc))
75		return false;
76
77	generic_handle_irq_desc(desc);
78	return true;
79}

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