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(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, irq_default_affinity))
60		cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
61	last_cpu = cpu;
62
63	irq_data_update_affinity(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(p, "IPI: ");
75	for_each_online_cpu(j)
76		seq_printf(p, "%10lu ", cpu_data[j].ipi_count);
77	seq_putc(p, '\n');
78#endif
79	seq_puts(p, "PMI: ");
80	for_each_online_cpu(j)
81		seq_printf(p, "%10lu ", per_cpu(irq_pmi_count, j));
82	seq_puts(p, "          Performance Monitoring\n");
83	seq_printf(p, "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