xref: /openbmc/linux/arch/arm64/kernel/irq.c (revision e50c55c2)
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/numa.h>
26 #include <asm/softirq_stack.h>
27 #include <asm/stacktrace.h>
28 #include <asm/vmap_stack.h>
29 
30 /* Only access this in an NMI enter/exit */
31 DEFINE_PER_CPU(struct nmi_ctx, nmi_contexts);
32 
33 DEFINE_PER_CPU(unsigned long *, irq_stack_ptr);
34 
35 
36 DECLARE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr);
37 
38 #ifdef CONFIG_SHADOW_CALL_STACK
39 DEFINE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr);
40 #endif
41 
init_irq_scs(void)42 static void init_irq_scs(void)
43 {
44 	int cpu;
45 
46 	if (!scs_is_enabled())
47 		return;
48 
49 	for_each_possible_cpu(cpu)
50 		per_cpu(irq_shadow_call_stack_ptr, cpu) =
51 			scs_alloc(early_cpu_to_node(cpu));
52 }
53 
54 #ifdef CONFIG_VMAP_STACK
init_irq_stacks(void)55 static void __init init_irq_stacks(void)
56 {
57 	int cpu;
58 	unsigned long *p;
59 
60 	for_each_possible_cpu(cpu) {
61 		p = arch_alloc_vmap_stack(IRQ_STACK_SIZE, early_cpu_to_node(cpu));
62 		per_cpu(irq_stack_ptr, cpu) = p;
63 	}
64 }
65 #else
66 /* irq stack only needs to be 16 byte aligned - not IRQ_STACK_SIZE aligned. */
67 DEFINE_PER_CPU_ALIGNED(unsigned long [IRQ_STACK_SIZE/sizeof(long)], irq_stack);
68 
init_irq_stacks(void)69 static void init_irq_stacks(void)
70 {
71 	int cpu;
72 
73 	for_each_possible_cpu(cpu)
74 		per_cpu(irq_stack_ptr, cpu) = per_cpu(irq_stack, cpu);
75 }
76 #endif
77 
78 #ifndef CONFIG_PREEMPT_RT
____do_softirq(struct pt_regs * regs)79 static void ____do_softirq(struct pt_regs *regs)
80 {
81 	__do_softirq();
82 }
83 
do_softirq_own_stack(void)84 void do_softirq_own_stack(void)
85 {
86 	call_on_irq_stack(NULL, ____do_softirq);
87 }
88 #endif
89 
default_handle_irq(struct pt_regs * regs)90 static void default_handle_irq(struct pt_regs *regs)
91 {
92 	panic("IRQ taken without a root IRQ handler\n");
93 }
94 
default_handle_fiq(struct pt_regs * regs)95 static void default_handle_fiq(struct pt_regs *regs)
96 {
97 	panic("FIQ taken without a root FIQ handler\n");
98 }
99 
100 void (*handle_arch_irq)(struct pt_regs *) __ro_after_init = default_handle_irq;
101 void (*handle_arch_fiq)(struct pt_regs *) __ro_after_init = default_handle_fiq;
102 
set_handle_irq(void (* handle_irq)(struct pt_regs *))103 int __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
104 {
105 	if (handle_arch_irq != default_handle_irq)
106 		return -EBUSY;
107 
108 	handle_arch_irq = handle_irq;
109 	pr_info("Root IRQ handler: %ps\n", handle_irq);
110 	return 0;
111 }
112 
set_handle_fiq(void (* handle_fiq)(struct pt_regs *))113 int __init set_handle_fiq(void (*handle_fiq)(struct pt_regs *))
114 {
115 	if (handle_arch_fiq != default_handle_fiq)
116 		return -EBUSY;
117 
118 	handle_arch_fiq = handle_fiq;
119 	pr_info("Root FIQ handler: %ps\n", handle_fiq);
120 	return 0;
121 }
122 
init_IRQ(void)123 void __init init_IRQ(void)
124 {
125 	init_irq_stacks();
126 	init_irq_scs();
127 	irqchip_init();
128 
129 	if (system_uses_irq_prio_masking()) {
130 		/*
131 		 * Now that we have a stack for our IRQ handler, set
132 		 * the PMR/PSR pair to a consistent state.
133 		 */
134 		WARN_ON(read_sysreg(daif) & PSR_A_BIT);
135 		local_daif_restore(DAIF_PROCCTX_NOIRQ);
136 	}
137 }
138