1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Based on arch/arm/kernel/irq.c 4 * 5 * Copyright (C) 1992 Linus Torvalds 6 * Modifications for ARM processor Copyright (C) 1995-2000 Russell King. 7 * Support for Dynamic Tick Timer Copyright (C) 2004-2005 Nokia Corporation. 8 * Dynamic Tick Timer written by Tony Lindgren <tony@atomide.com> and 9 * Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>. 10 * Copyright (C) 2012 ARM Ltd. 11 */ 12 13 #include <linux/hardirq.h> 14 #include <linux/init.h> 15 #include <linux/irq.h> 16 #include <linux/irqchip.h> 17 #include <linux/kprobes.h> 18 #include <linux/memory.h> 19 #include <linux/scs.h> 20 #include <linux/seq_file.h> 21 #include <linux/smp.h> 22 #include <linux/vmalloc.h> 23 #include <asm/daifflags.h> 24 #include <asm/exception.h> 25 #include <asm/softirq_stack.h> 26 #include <asm/stacktrace.h> 27 #include <asm/vmap_stack.h> 28 29 /* Only access this in an NMI enter/exit */ 30 DEFINE_PER_CPU(struct nmi_ctx, nmi_contexts); 31 32 DEFINE_PER_CPU(unsigned long *, irq_stack_ptr); 33 34 35 DECLARE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr); 36 37 #ifdef CONFIG_SHADOW_CALL_STACK 38 DEFINE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr); 39 #endif 40 41 static void init_irq_scs(void) 42 { 43 int cpu; 44 45 if (!IS_ENABLED(CONFIG_SHADOW_CALL_STACK)) 46 return; 47 48 for_each_possible_cpu(cpu) 49 per_cpu(irq_shadow_call_stack_ptr, cpu) = 50 scs_alloc(cpu_to_node(cpu)); 51 } 52 53 #ifdef CONFIG_VMAP_STACK 54 static void init_irq_stacks(void) 55 { 56 int cpu; 57 unsigned long *p; 58 59 for_each_possible_cpu(cpu) { 60 p = arch_alloc_vmap_stack(IRQ_STACK_SIZE, cpu_to_node(cpu)); 61 per_cpu(irq_stack_ptr, cpu) = p; 62 } 63 } 64 #else 65 /* irq stack only needs to be 16 byte aligned - not IRQ_STACK_SIZE aligned. */ 66 DEFINE_PER_CPU_ALIGNED(unsigned long [IRQ_STACK_SIZE/sizeof(long)], irq_stack); 67 68 static void init_irq_stacks(void) 69 { 70 int cpu; 71 72 for_each_possible_cpu(cpu) 73 per_cpu(irq_stack_ptr, cpu) = per_cpu(irq_stack, cpu); 74 } 75 #endif 76 77 #ifndef CONFIG_PREEMPT_RT 78 static void ____do_softirq(struct pt_regs *regs) 79 { 80 __do_softirq(); 81 } 82 83 void do_softirq_own_stack(void) 84 { 85 call_on_irq_stack(NULL, ____do_softirq); 86 } 87 #endif 88 89 static void default_handle_irq(struct pt_regs *regs) 90 { 91 panic("IRQ taken without a root IRQ handler\n"); 92 } 93 94 static void default_handle_fiq(struct pt_regs *regs) 95 { 96 panic("FIQ taken without a root FIQ handler\n"); 97 } 98 99 void (*handle_arch_irq)(struct pt_regs *) __ro_after_init = default_handle_irq; 100 void (*handle_arch_fiq)(struct pt_regs *) __ro_after_init = default_handle_fiq; 101 102 int __init set_handle_irq(void (*handle_irq)(struct pt_regs *)) 103 { 104 if (handle_arch_irq != default_handle_irq) 105 return -EBUSY; 106 107 handle_arch_irq = handle_irq; 108 pr_info("Root IRQ handler: %ps\n", handle_irq); 109 return 0; 110 } 111 112 int __init set_handle_fiq(void (*handle_fiq)(struct pt_regs *)) 113 { 114 if (handle_arch_fiq != default_handle_fiq) 115 return -EBUSY; 116 117 handle_arch_fiq = handle_fiq; 118 pr_info("Root FIQ handler: %ps\n", handle_fiq); 119 return 0; 120 } 121 122 void __init init_IRQ(void) 123 { 124 init_irq_stacks(); 125 init_irq_scs(); 126 irqchip_init(); 127 128 if (system_uses_irq_prio_masking()) { 129 /* 130 * Now that we have a stack for our IRQ handler, set 131 * the PMR/PSR pair to a consistent state. 132 */ 133 WARN_ON(read_sysreg(daif) & PSR_A_BIT); 134 local_daif_restore(DAIF_PROCCTX_NOIRQ); 135 } 136 } 137