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 #include "irq_impl.h"
32
33 volatile unsigned long irq_err_count;
34 DEFINE_PER_CPU(unsigned long, irq_pmi_count);
35
ack_bad_irq(unsigned int irq)36 void ack_bad_irq(unsigned int irq)
37 {
38 irq_err_count++;
39 printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq);
40 }
41
42 #ifdef CONFIG_SMP
43 static char irq_user_affinity[NR_IRQS];
44
irq_select_affinity(unsigned int irq)45 int irq_select_affinity(unsigned int irq)
46 {
47 struct irq_data *data = irq_get_irq_data(irq);
48 struct irq_chip *chip;
49 static int last_cpu;
50 int cpu = last_cpu + 1;
51
52 if (!data)
53 return 1;
54 chip = irq_data_get_irq_chip(data);
55
56 if (!chip->irq_set_affinity || irq_user_affinity[irq])
57 return 1;
58
59 while (!cpu_possible(cpu) ||
60 !cpumask_test_cpu(cpu, irq_default_affinity))
61 cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
62 last_cpu = cpu;
63
64 irq_data_update_affinity(data, cpumask_of(cpu));
65 chip->irq_set_affinity(data, cpumask_of(cpu), false);
66 return 0;
67 }
68 #endif /* CONFIG_SMP */
69
arch_show_interrupts(struct seq_file * p,int prec)70 int arch_show_interrupts(struct seq_file *p, int prec)
71 {
72 int j;
73
74 #ifdef CONFIG_SMP
75 seq_puts(p, "IPI: ");
76 for_each_online_cpu(j)
77 seq_printf(p, "%10lu ", cpu_data[j].ipi_count);
78 seq_putc(p, '\n');
79 #endif
80 seq_puts(p, "PMI: ");
81 for_each_online_cpu(j)
82 seq_printf(p, "%10lu ", per_cpu(irq_pmi_count, j));
83 seq_puts(p, " Performance Monitoring\n");
84 seq_printf(p, "ERR: %10lu\n", irq_err_count);
85 return 0;
86 }
87
88 /*
89 * handle_irq handles all normal device IRQ's (the special
90 * SMP cross-CPU interrupts have their own specific
91 * handlers).
92 */
93
94 #define MAX_ILLEGAL_IRQS 16
95
96 void
handle_irq(int irq)97 handle_irq(int irq)
98 {
99 /*
100 * We ack quickly, we don't want the irq controller
101 * thinking we're snobs just because some other CPU has
102 * disabled global interrupts (we have already done the
103 * INT_ACK cycles, it's too late to try to pretend to the
104 * controller that we aren't taking the interrupt).
105 *
106 * 0 return value means that this irq is already being
107 * handled by some other CPU. (or is disabled)
108 */
109 static unsigned int illegal_count=0;
110 struct irq_desc *desc = irq_to_desc(irq);
111
112 if (!desc || ((unsigned) irq > ACTUAL_NR_IRQS &&
113 illegal_count < MAX_ILLEGAL_IRQS)) {
114 irq_err_count++;
115 illegal_count++;
116 printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n",
117 irq);
118 return;
119 }
120
121 irq_enter();
122 generic_handle_irq_desc(desc);
123 irq_exit();
124 }
125