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// 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/irq.h>
15#include <linux/seq_file.h>
16#include <linux/delay.h>
17#include <linux/ftrace.h>
18#include <linux/uaccess.h>
19#include <linux/smp.h>
20#include <linux/sched/task_stack.h>
21
22#include <asm/cpu_entry_area.h>
23#include <asm/softirq_stack.h>
24#include <asm/irq_stack.h>
25#include <asm/io_apic.h>
26#include <asm/apic.h>
27
28DEFINE_PER_CPU_PAGE_ALIGNED(struct irq_stack, irq_stack_backing_store) __visible;
29DECLARE_INIT_PER_CPU(irq_stack_backing_store);
30
31#ifdef CONFIG_VMAP_STACK
32/*
33 * VMAP the backing store with guard pages
 
 
 
 
34 */
35static int map_irq_stack(unsigned int cpu)
36{
37	char *stack = (char *)per_cpu_ptr(&irq_stack_backing_store, cpu);
38	struct page *pages[IRQ_STACK_SIZE / PAGE_SIZE];
39	void *va;
40	int i;
41
42	for (i = 0; i < IRQ_STACK_SIZE / PAGE_SIZE; i++) {
43		phys_addr_t pa = per_cpu_ptr_to_phys(stack + (i << PAGE_SHIFT));
44
45		pages[i] = pfn_to_page(pa >> PAGE_SHIFT);
46	}
47
48	va = vmap(pages, IRQ_STACK_SIZE / PAGE_SIZE, VM_MAP, PAGE_KERNEL);
49	if (!va)
50		return -ENOMEM;
51
52	/* Store actual TOS to avoid adjustment in the hotpath */
53	per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE - 8;
54	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
55}
56#else
57/*
58 * If VMAP stacks are disabled due to KASAN, just use the per cpu
59 * backing store without guard pages.
60 */
61static int map_irq_stack(unsigned int cpu)
62{
63	void *va = per_cpu_ptr(&irq_stack_backing_store, cpu);
64
65	/* Store actual TOS to avoid adjustment in the hotpath */
66	per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE - 8;
67	return 0;
68}
69#endif
70
71int irq_init_percpu_irqstack(unsigned int cpu)
72{
73	if (per_cpu(hardirq_stack_ptr, cpu))
74		return 0;
75	return map_irq_stack(cpu);
76}