arch/x86/kernel/irq_64.c

   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
  26 DEFINE_PER_CPU_PAGE_ALIGNED(struct irq_stack, irq_stack_backing_store) __visible;
  27 DECLARE_INIT_PER_CPU(irq_stack_backing_store);
  28
  29 #ifdef CONFIG_VMAP_STACK
  30 /*
  31  * VMAP the backing store with guard pages
  32  */
  33 static 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, VM_MAP, 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  */
  58 static 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
  67 int 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 }