1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/arch/alpha/kernel/irq.c
4 *
5 * Copyright (C) 1995 Linus Torvalds
6 *
7 * This file contains the code used by various IRQ handling routines:
8 * asking for different IRQ's should be done through these routines
9 * instead of just grabbing them. Thus setups with different IRQ numbers
10 * shouldn't result in any weird surprises, and installing new handlers
11 * should be easier.
12 */
13
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/errno.h>
17#include <linux/kernel_stat.h>
18#include <linux/signal.h>
19#include <linux/sched.h>
20#include <linux/ptrace.h>
21#include <linux/interrupt.h>
22#include <linux/random.h>
23#include <linux/irq.h>
24#include <linux/proc_fs.h>
25#include <linux/seq_file.h>
26#include <linux/profile.h>
27#include <linux/bitops.h>
28
29#include <asm/io.h>
30#include <linux/uaccess.h>
31
32volatile unsigned long irq_err_count;
33DEFINE_PER_CPU(unsigned long, irq_pmi_count);
34
35void ack_bad_irq(unsigned int irq)
36{
37 irq_err_count++;
38 printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq);
39}
40
41#ifdef CONFIG_SMP
42static char irq_user_affinity[NR_IRQS];
43
44int irq_select_affinity(unsigned int irq)
45{
46 struct irq_data *data = irq_get_irq_data(irq);
47 struct irq_chip *chip;
48 static int last_cpu;
49 int cpu = last_cpu + 1;
50
51 if (!data)
52 return 1;
53 chip = irq_data_get_irq_chip(d: data);
54
55 if (!chip->irq_set_affinity || irq_user_affinity[irq])
56 return 1;
57
58 while (!cpu_possible(cpu) ||
59 !cpumask_test_cpu(cpu, cpumask: irq_default_affinity))
60 cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
61 last_cpu = cpu;
62
63 irq_data_update_affinity(d: data, cpumask_of(cpu));
64 chip->irq_set_affinity(data, cpumask_of(cpu), false);
65 return 0;
66}
67#endif /* CONFIG_SMP */
68
69int arch_show_interrupts(struct seq_file *p, int prec)
70{
71 int j;
72
73#ifdef CONFIG_SMP
74 seq_puts(m: p, s: "IPI: ");
75 for_each_online_cpu(j)
76 seq_printf(p, "%10lu ", cpu_data[j].ipi_count);
77 seq_putc(m: p, c: '\n');
78#endif
79 seq_puts(m: p, s: "PMI: ");
80 for_each_online_cpu(j)
81 seq_printf(m: p, fmt: "%10lu ", per_cpu(irq_pmi_count, j));
82 seq_puts(m: p, s: " Performance Monitoring\n");
83 seq_printf(m: p, fmt: "ERR: %10lu\n", irq_err_count);
84 return 0;
85}
86
87/*
88 * handle_irq handles all normal device IRQ's (the special
89 * SMP cross-CPU interrupts have their own specific
90 * handlers).
91 */
92
93#define MAX_ILLEGAL_IRQS 16
94
95void
96handle_irq(int irq)
97{
98 /*
99 * We ack quickly, we don't want the irq controller
100 * thinking we're snobs just because some other CPU has
101 * disabled global interrupts (we have already done the
102 * INT_ACK cycles, it's too late to try to pretend to the
103 * controller that we aren't taking the interrupt).
104 *
105 * 0 return value means that this irq is already being
106 * handled by some other CPU. (or is disabled)
107 */
108 static unsigned int illegal_count=0;
109 struct irq_desc *desc = irq_to_desc(irq);
110
111 if (!desc || ((unsigned) irq > ACTUAL_NR_IRQS &&
112 illegal_count < MAX_ILLEGAL_IRQS)) {
113 irq_err_count++;
114 illegal_count++;
115 printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n",
116 irq);
117 return;
118 }
119
120 irq_enter();
121 generic_handle_irq_desc(desc);
122 irq_exit();
123}
124

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