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/softirq_stack.h> 24 #include <asm/irq_stack.h> 25 #include <asm/io_apic.h> 26 #include <asm/apic.h> 27 28 DEFINE_PER_CPU_PAGE_ALIGNED(struct irq_stack, irq_stack_backing_store) __visible; 29 DECLARE_INIT_PER_CPU(irq_stack_backing_store); 30 31 #ifdef CONFIG_VMAP_STACK 32 /* 33 * VMAP the backing store with guard pages 34 */ 35 static int map_irq_stack(unsigned int cpu) 36 { 37 char *stack = (char *)per_cpu_ptr(&irq_stack_backing_store, cpu); 38 struct page *pages[IRQ_STACK_SIZE / PAGE_SIZE]; 39 void *va; 40 int i; 41 42 for (i = 0; i < IRQ_STACK_SIZE / PAGE_SIZE; i++) { 43 phys_addr_t pa = per_cpu_ptr_to_phys(stack + (i << PAGE_SHIFT)); 44 45 pages[i] = pfn_to_page(pa >> PAGE_SHIFT); 46 } 47 48 va = vmap(pages, IRQ_STACK_SIZE / PAGE_SIZE, VM_MAP, PAGE_KERNEL); 49 if (!va) 50 return -ENOMEM; 51 52 /* Store actual TOS to avoid adjustment in the hotpath */ 53 per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE - 8; 54 return 0; 55 } 56 #else 57 /* 58 * If VMAP stacks are disabled due to KASAN, just use the per cpu 59 * backing store without guard pages. 60 */ 61 static int map_irq_stack(unsigned int cpu) 62 { 63 void *va = per_cpu_ptr(&irq_stack_backing_store, cpu); 64 65 /* Store actual TOS to avoid adjustment in the hotpath */ 66 per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE - 8; 67 return 0; 68 } 69 #endif 70 71 int irq_init_percpu_irqstack(unsigned int cpu) 72 { 73 if (per_cpu(hardirq_stack_ptr, cpu)) 74 return 0; 75 return map_irq_stack(cpu); 76 } 77