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, GFP_KERNEL, 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 } 73