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 bool handle_irq(struct irq_desc *desc, struct pt_regs *regs)
  30 {
  31         if (IS_ERR_OR_NULL(desc))
  32                 return false;
  33
  34         generic_handle_irq_desc(desc);
  35         return true;
  36 }
  37
  38 #ifdef CONFIG_VMAP_STACK
  39 /*
  40  * VMAP the backing store with guard pages
  41  */
  42 static int map_irq_stack(unsigned int cpu)
  43 {
  44         char *stack = (char *)per_cpu_ptr(&irq_stack_backing_store, cpu);
  45         struct page *pages[IRQ_STACK_SIZE / PAGE_SIZE];
  46         void *va;
  47         int i;
  48
  49         for (i = 0; i < IRQ_STACK_SIZE / PAGE_SIZE; i++) {
  50                 phys_addr_t pa = per_cpu_ptr_to_phys(stack + (i << PAGE_SHIFT));
  51
  52                 pages[i] = pfn_to_page(pa >> PAGE_SHIFT);
  53         }
  54
  55         va = vmap(pages, IRQ_STACK_SIZE / PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
  56         if (!va)
  57                 return -ENOMEM;
  58
  59         per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE;
  60         return 0;
  61 }
  62 #else
  63 /*
  64  * If VMAP stacks are disabled due to KASAN, just use the per cpu
  65  * backing store without guard pages.
  66  */
  67 static int map_irq_stack(unsigned int cpu)
  68 {
  69         void *va = per_cpu_ptr(&irq_stack_backing_store, cpu);
  70
  71         per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE;
  72         return 0;
  73 }
  74 #endif
  75
  76 int irq_init_percpu_irqstack(unsigned int cpu)
  77 {
  78         if (per_cpu(hardirq_stack_ptr, cpu))
  79                 return 0;
  80         return map_irq_stack(cpu);
  81 }