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/io_apic.h>
 
24#include <asm/apic.h>
25
26DEFINE_PER_CPU_PAGE_ALIGNED(struct irq_stack, irq_stack_backing_store) __visible;
27DECLARE_INIT_PER_CPU(irq_stack_backing_store);
28
29#ifdef CONFIG_VMAP_STACK
30/*
31 * VMAP the backing store with guard pages
 
 
 
 
32 */
33static int map_irq_stack(unsigned int cpu)
34{
35	char *stack = (char *)per_cpu_ptr(&irq_stack_backing_store, cpu);
36	struct page *pages[IRQ_STACK_SIZE / PAGE_SIZE];
37	void *va;
38	int i;
39
40	for (i = 0; i < IRQ_STACK_SIZE / PAGE_SIZE; i++) {
41		phys_addr_t pa = per_cpu_ptr_to_phys(stack + (i << PAGE_SHIFT));
42
43		pages[i] = pfn_to_page(pa >> PAGE_SHIFT);
44	}
45
46	va = vmap(pages, IRQ_STACK_SIZE / PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
47	if (!va)
48		return -ENOMEM;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
49
50	per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE;
51	return 0;
 
52}
53#else
54/*
55 * If VMAP stacks are disabled due to KASAN, just use the per cpu
56 * backing store without guard pages.
57 */
58static int map_irq_stack(unsigned int cpu)
59{
60	void *va = per_cpu_ptr(&irq_stack_backing_store, cpu);
61
62	per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE;
63	return 0;
64}
65#endif
66
67int irq_init_percpu_irqstack(unsigned int cpu)
68{
69	if (per_cpu(hardirq_stack_ptr, cpu))
70		return 0;
71	return map_irq_stack(cpu);
72}

 
 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
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 thread_info) +
45				  sizeof(struct pt_regs) + STACK_TOP_MARGIN &&
46	    regs->sp <= curbase + THREAD_SIZE)
47		return;
48
49	irq_stack_top = (u64)this_cpu_ptr(irq_stack_union.irq_stack) +
50			STACK_TOP_MARGIN;
51	irq_stack_bottom = (u64)__this_cpu_read(irq_stack_ptr);
52	if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom)
53		return;
54
55	oist = this_cpu_ptr(&orig_ist);
56	estack_top = (u64)oist->ist[0] - EXCEPTION_STKSZ + STACK_TOP_MARGIN;
57	estack_bottom = (u64)oist->ist[N_EXCEPTION_STACKS - 1];
58	if (regs->sp >= estack_top && regs->sp <= estack_bottom)
59		return;
60
61	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",
62		current->comm, curbase, regs->sp,
63		irq_stack_top, irq_stack_bottom,
64		estack_top, estack_bottom);
65
66	if (sysctl_panic_on_stackoverflow)
67		panic("low stack detected by irq handler - check messages\n");
68#endif
69}
70
71bool handle_irq(struct irq_desc *desc, struct pt_regs *regs)
 
 
 
 
72{
73	stack_overflow_check(regs);
74
75	if (IS_ERR_OR_NULL(desc))
76		return false;
 
 
77
78	generic_handle_irq_desc(desc);
79	return true;
 
 
 
80}