LXR linux/arch/x86/kernel/irq

   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}
  77