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