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 */
30DEFINE_PER_CPU(struct nmi_ctx, nmi_contexts);
31
32DEFINE_PER_CPU(unsigned long *, irq_stack_ptr);
33
34
35DECLARE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr);
36
37#ifdef CONFIG_SHADOW_CALL_STACK
38DEFINE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr);
39#endif
40
41static void init_irq_scs(void)
42{
43 int cpu;
44
45 if (!scs_is_enabled())
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
54static 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. */
66DEFINE_PER_CPU_ALIGNED(unsigned long [IRQ_STACK_SIZE/sizeof(long)], irq_stack);
67
68static 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
78static void ____do_softirq(struct pt_regs *regs)
79{
80 __do_softirq();
81}
82
83void do_softirq_own_stack(void)
84{
85 call_on_irq_stack(NULL, ____do_softirq);
86}
87#endif
88
89static void default_handle_irq(struct pt_regs *regs)
90{
91 panic(fmt: "IRQ taken without a root IRQ handler\n");
92}
93
94static void default_handle_fiq(struct pt_regs *regs)
95{
96 panic(fmt: "FIQ taken without a root FIQ handler\n");
97}
98
99void (*handle_arch_irq)(struct pt_regs *) __ro_after_init = default_handle_irq;
100void (*handle_arch_fiq)(struct pt_regs *) __ro_after_init = default_handle_fiq;
101
102int __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
112int __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
122void __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

source code of linux/arch/arm64/kernel/irq.c