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 
32 volatile unsigned long irq_err_count;
33 DEFINE_PER_CPU(unsigned long, irq_pmi_count);
34 
ack_bad_irq(unsigned int irq)35 void 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
42 static char irq_user_affinity[NR_IRQS];
43 
irq_select_affinity(unsigned int irq)44 int 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 
arch_show_interrupts(struct seq_file * p,int prec)69 int 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 
95 void
handle_irq(int irq)96 handle_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