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 #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
  29 DEFINE_PER_CPU_PAGE_ALIGNED(struct irq_stack, irq_stack_backing_store) __visible;
  30 DECLARE_INIT_PER_CPU(irq_stack_backing_store);
  31
  32 #ifdef CONFIG_VMAP_STACK
  33 /*
  34  * VMAP the backing store with guard pages
  35  */
  36 static 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(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(pcpu_hot.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  */
  62 static 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(pcpu_hot.hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE - 8;
  68         return 0;
  69 }
  70 #endif
  71
  72 int irq_init_percpu_irqstack(unsigned int cpu)
  73 {
  74         if (per_cpu(pcpu_hot.hardirq_stack_ptr, cpu))
  75                 return 0;
  76         return map_irq_stack(cpu);
  77 }