Root/arch/s390/kernel/irq.c

1/*
2 * arch/s390/kernel/irq.c
3 *
4 * Copyright IBM Corp. 2004,2007
5 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
6 * Thomas Spatzier (tspat@de.ibm.com)
7 *
8 * This file contains interrupt related functions.
9 */
10
11#include <linux/module.h>
12#include <linux/kernel.h>
13#include <linux/kernel_stat.h>
14#include <linux/interrupt.h>
15#include <linux/seq_file.h>
16#include <linux/cpu.h>
17#include <linux/proc_fs.h>
18#include <linux/profile.h>
19
20/*
21 * show_interrupts is needed by /proc/interrupts.
22 */
23int show_interrupts(struct seq_file *p, void *v)
24{
25    static const char *intrclass_names[] = { "EXT", "I/O", };
26    int i = *(loff_t *) v, j;
27
28    get_online_cpus();
29    if (i == 0) {
30        seq_puts(p, " ");
31        for_each_online_cpu(j)
32            seq_printf(p, "CPU%d ",j);
33        seq_putc(p, '\n');
34    }
35
36    if (i < NR_IRQS) {
37        seq_printf(p, "%s: ", intrclass_names[i]);
38#ifndef CONFIG_SMP
39        seq_printf(p, "%10u ", kstat_irqs(i));
40#else
41        for_each_online_cpu(j)
42            seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
43#endif
44                seq_putc(p, '\n');
45
46        }
47    put_online_cpus();
48        return 0;
49}
50
51/*
52 * For compatibilty only. S/390 specific setup of interrupts et al. is done
53 * much later in init_channel_subsystem().
54 */
55void __init
56init_IRQ(void)
57{
58    /* nothing... */
59}
60
61/*
62 * Switch to the asynchronous interrupt stack for softirq execution.
63 */
64asmlinkage void do_softirq(void)
65{
66    unsigned long flags, old, new;
67
68    if (in_interrupt())
69        return;
70
71    local_irq_save(flags);
72
73    if (local_softirq_pending()) {
74        /* Get current stack pointer. */
75        asm volatile("la %0,0(15)" : "=a" (old));
76        /* Check against async. stack address range. */
77        new = S390_lowcore.async_stack;
78        if (((new - old) >> (PAGE_SHIFT + THREAD_ORDER)) != 0) {
79            /* Need to switch to the async. stack. */
80            new -= STACK_FRAME_OVERHEAD;
81            ((struct stack_frame *) new)->back_chain = old;
82
83            asm volatile(" la 15,0(%0)\n"
84                     " basr 14,%2\n"
85                     " la 15,0(%1)\n"
86                     : : "a" (new), "a" (old),
87                         "a" (__do_softirq)
88                     : "0", "1", "2", "3", "4", "5", "14",
89                       "cc", "memory" );
90        } else
91            /* We are already on the async stack. */
92            __do_softirq();
93    }
94
95    local_irq_restore(flags);
96}
97
98#ifdef CONFIG_PROC_FS
99void init_irq_proc(void)
100{
101    struct proc_dir_entry *root_irq_dir;
102
103    root_irq_dir = proc_mkdir("irq", NULL);
104    create_prof_cpu_mask(root_irq_dir);
105}
106#endif
107

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