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 } 82