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#include <linux/vmalloc.h>
22
23#include <asm/cpu_entry_area.h>
24#include <asm/softirq_stack.h>
25#include <asm/irq_stack.h>
26#include <asm/io_apic.h>
27#include <asm/apic.h>
28
29DEFINE_PER_CPU_CACHE_HOT(bool, hardirq_stack_inuse);
30DEFINE_PER_CPU_PAGE_ALIGNED(struct irq_stack, irq_stack_backing_store) __visible;
31
32#ifdef CONFIG_VMAP_STACK
33/*
34 * VMAP the backing store with guard pages
35 */
36static int map_irq_stack(unsigned int cpu)
37{
38 char *stack = (char *)per_cpu_ptr(&irq_stack_backing_store, cpu);
39 struct page *pages[IRQ_STACK_SIZE / PAGE_SIZE];
40 void *va;
41 int i;
42
43 for (i = 0; i < IRQ_STACK_SIZE / PAGE_SIZE; i++) {
44 phys_addr_t pa = per_cpu_ptr_to_phys(addr: stack + (i << PAGE_SHIFT));
45
46 pages[i] = pfn_to_page(pa >> PAGE_SHIFT);
47 }
48
49 va = vmap(pages, IRQ_STACK_SIZE / PAGE_SIZE, VM_MAP, PAGE_KERNEL);
50 if (!va)
51 return -ENOMEM;
52
53 /* Store actual TOS to avoid adjustment in the hotpath */
54 per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE - 8;
55 return 0;
56}
57#else
58/*
59 * If VMAP stacks are disabled due to KASAN, just use the per cpu
60 * backing store without guard pages.
61 */
62static int map_irq_stack(unsigned int cpu)
63{
64 void *va = per_cpu_ptr(&irq_stack_backing_store, cpu);
65
66 /* Store actual TOS to avoid adjustment in the hotpath */
67 per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE - 8;
68 return 0;
69}
70#endif
71
72int irq_init_percpu_irqstack(unsigned int cpu)
73{
74 if (per_cpu(hardirq_stack_ptr, cpu))
75 return 0;
76 return map_irq_stack(cpu);
77}
78

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