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