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/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
23DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
24EXPORT_PER_CPU_SYMBOL(irq_stat);
25
26DEFINE_PER_CPU(struct pt_regs *, irq_regs);
27EXPORT_PER_CPU_SYMBOL(irq_regs);
28
29/*
30 * Probabilistic stack overflow check:
31 *
32 * Only check the stack in process context, because everything else
33 * runs on the big interrupt stacks. Checking reliably is too expensive,
34 * so we just check from interrupts.
35 */
36static inline void stack_overflow_check(struct pt_regs *regs)
37{
38#ifdef CONFIG_DEBUG_STACKOVERFLOW
 
 
 
 
39	u64 curbase = (u64)task_stack_page(current);
40
41	WARN_ONCE(regs->sp >= curbase &&
42		  regs->sp <= curbase + THREAD_SIZE &&
43		  regs->sp <  curbase + sizeof(struct thread_info) +
44					sizeof(struct pt_regs) + 128,
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
45
46		  "do_IRQ: %s near stack overflow (cur:%Lx,sp:%lx)\n",
47			current->comm, curbase, regs->sp);
48#endif
49}
50
51bool handle_irq(unsigned irq, struct pt_regs *regs)
52{
53	struct irq_desc *desc;
54
55	stack_overflow_check(regs);
56
57	desc = irq_to_desc(irq);
58	if (unlikely(!desc))
59		return false;
60
61	generic_handle_irq_desc(irq, desc);
62	return true;
63}
64
65
66extern void call_softirq(void);
67
68asmlinkage void do_softirq(void)
69{
70	__u32 pending;
71	unsigned long flags;
72
73	if (in_interrupt())
74		return;
75
76	local_irq_save(flags);
77	pending = local_softirq_pending();
78	/* Switch to interrupt stack */
79	if (pending) {
80		call_softirq();
81		WARN_ON_ONCE(softirq_count());
82	}
83	local_irq_restore(flags);
84}