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(addr: 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(pcpu_hot.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(pcpu_hot.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(pcpu_hot.hardirq_stack_ptr, cpu))
74 return 0;
75 return map_irq_stack(cpu);
76}
77

source code of linux/arch/x86/kernel/irq_64.c