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 } 78