Root/arch/s390/kernel/s390_ext.c

1/*
2 * arch/s390/kernel/s390_ext.c
3 *
4 * S390 version
5 * Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
6 * Author(s): Holger Smolinski (Holger.Smolinski@de.ibm.com),
7 * Martin Schwidefsky (schwidefsky@de.ibm.com)
8 */
9
10#include <linux/module.h>
11#include <linux/kernel.h>
12#include <linux/slab.h>
13#include <linux/ftrace.h>
14#include <linux/errno.h>
15#include <linux/kernel_stat.h>
16#include <linux/interrupt.h>
17#include <asm/cputime.h>
18#include <asm/lowcore.h>
19#include <asm/s390_ext.h>
20#include <asm/irq_regs.h>
21#include <asm/irq.h>
22#include "entry.h"
23
24/*
25 * ext_int_hash[index] is the start of the list for all external interrupts
26 * that hash to this index. With the current set of external interrupts
27 * (0x1202 external call, 0x1004 cpu timer, 0x2401 hwc console, 0x4000
28 * iucv and 0x2603 pfault) this is always the first element.
29 */
30ext_int_info_t *ext_int_hash[256] = { NULL, };
31
32static inline int ext_hash(__u16 code)
33{
34    return (code + (code >> 9)) & 0xff;
35}
36
37int register_external_interrupt(__u16 code, ext_int_handler_t handler)
38{
39        ext_int_info_t *p;
40        int index;
41
42    p = kmalloc(sizeof(ext_int_info_t), GFP_ATOMIC);
43        if (p == NULL)
44                return -ENOMEM;
45        p->code = code;
46        p->handler = handler;
47    index = ext_hash(code);
48        p->next = ext_int_hash[index];
49        ext_int_hash[index] = p;
50        return 0;
51}
52
53int register_early_external_interrupt(__u16 code, ext_int_handler_t handler,
54                      ext_int_info_t *p)
55{
56        int index;
57
58        if (p == NULL)
59                return -EINVAL;
60        p->code = code;
61        p->handler = handler;
62    index = ext_hash(code);
63        p->next = ext_int_hash[index];
64        ext_int_hash[index] = p;
65        return 0;
66}
67
68int unregister_external_interrupt(__u16 code, ext_int_handler_t handler)
69{
70        ext_int_info_t *p, *q;
71        int index;
72
73    index = ext_hash(code);
74        q = NULL;
75        p = ext_int_hash[index];
76        while (p != NULL) {
77                if (p->code == code && p->handler == handler)
78                        break;
79                q = p;
80                p = p->next;
81        }
82        if (p == NULL)
83                return -ENOENT;
84        if (q != NULL)
85                q->next = p->next;
86        else
87                ext_int_hash[index] = p->next;
88    kfree(p);
89        return 0;
90}
91
92int unregister_early_external_interrupt(__u16 code, ext_int_handler_t handler,
93                    ext_int_info_t *p)
94{
95    ext_int_info_t *q;
96    int index;
97
98    if (p == NULL || p->code != code || p->handler != handler)
99        return -EINVAL;
100    index = ext_hash(code);
101    q = ext_int_hash[index];
102    if (p != q) {
103        while (q != NULL) {
104            if (q->next == p)
105                break;
106            q = q->next;
107        }
108        if (q == NULL)
109            return -ENOENT;
110        q->next = p->next;
111    } else
112        ext_int_hash[index] = p->next;
113    return 0;
114}
115
116void __irq_entry do_extint(struct pt_regs *regs, unsigned int ext_int_code,
117               unsigned int param32, unsigned long param64)
118{
119    struct pt_regs *old_regs;
120    unsigned short code;
121        ext_int_info_t *p;
122        int index;
123
124    code = (unsigned short) ext_int_code;
125    old_regs = set_irq_regs(regs);
126    s390_idle_check(regs, S390_lowcore.int_clock,
127            S390_lowcore.async_enter_timer);
128    irq_enter();
129    if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator)
130        /* Serve timer interrupts first. */
131        clock_comparator_work();
132    kstat_cpu(smp_processor_id()).irqs[EXTERNAL_INTERRUPT]++;
133    if (code != 0x1004)
134        __get_cpu_var(s390_idle).nohz_delay = 1;
135        index = ext_hash(code);
136    for (p = ext_int_hash[index]; p; p = p->next) {
137        if (likely(p->code == code))
138            p->handler(ext_int_code, param32, param64);
139    }
140    irq_exit();
141    set_irq_regs(old_regs);
142}
143
144EXPORT_SYMBOL(register_external_interrupt);
145EXPORT_SYMBOL(unregister_external_interrupt);
146

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