summaryrefslogtreecommitdiff
path: root/arch/s390/kernel/s390_ext.c
blob: 87b5c532abf1faf132e85bf4158869c1677493f1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
/*
 *    Copyright IBM Corp. 1999,2010
 *    Author(s): Holger Smolinski <Holger.Smolinski@de.ibm.com>,
 *		 Martin Schwidefsky <schwidefsky@de.ibm.com>,
 */

#include <linux/kernel_stat.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/ftrace.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <asm/s390_ext.h>
#include <asm/irq_regs.h>
#include <asm/cputime.h>
#include <asm/lowcore.h>
#include <asm/irq.h>
#include "entry.h"

struct ext_int_info {
	struct ext_int_info *next;
	ext_int_handler_t handler;
	__u16 code;
};

/*
 * ext_int_hash[index] is the start of the list for all external interrupts
 * that hash to this index. With the current set of external interrupts 
 * (0x1202 external call, 0x1004 cpu timer, 0x2401 hwc console, 0x4000
 * iucv and 0x2603 pfault) this is always the first element. 
 */
static struct ext_int_info *ext_int_hash[256];

static inline int ext_hash(__u16 code)
{
	return (code + (code >> 9)) & 0xff;
}

int register_external_interrupt(__u16 code, ext_int_handler_t handler)
{
	struct ext_int_info *p;
	int index;

	p = kmalloc(sizeof(*p), GFP_ATOMIC);
	if (!p)
		return -ENOMEM;
	p->code = code;
	p->handler = handler;
	index = ext_hash(code);
	p->next = ext_int_hash[index];
	ext_int_hash[index] = p;
	return 0;
}
EXPORT_SYMBOL(register_external_interrupt);

int unregister_external_interrupt(__u16 code, ext_int_handler_t handler)
{
	struct ext_int_info *p, *q;
	int index;

	index = ext_hash(code);
	q = NULL;
	p = ext_int_hash[index];
	while (p) {
		if (p->code == code && p->handler == handler)
			break;
		q = p;
		p = p->next;
	}
	if (!p)
		return -ENOENT;
	if (q)
		q->next = p->next;
	else
		ext_int_hash[index] = p->next;
	kfree(p);
	return 0;
}
EXPORT_SYMBOL(unregister_external_interrupt);

void __irq_entry do_extint(struct pt_regs *regs, unsigned int ext_int_code,
			   unsigned int param32, unsigned long param64)
{
	struct pt_regs *old_regs;
	unsigned short code;
	struct ext_int_info *p;
	int index;

	code = (unsigned short) ext_int_code;
	old_regs = set_irq_regs(regs);
	s390_idle_check(regs, S390_lowcore.int_clock,
			S390_lowcore.async_enter_timer);
	irq_enter();
	if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator)
		/* Serve timer interrupts first. */
		clock_comparator_work();
	kstat_cpu(smp_processor_id()).irqs[EXTERNAL_INTERRUPT]++;
	if (code != 0x1004)
		__get_cpu_var(s390_idle).nohz_delay = 1;
	index = ext_hash(code);
	for (p = ext_int_hash[index]; p; p = p->next) {
		if (likely(p->code == code))
			p->handler(ext_int_code, param32, param64);
	}
	irq_exit();
	set_irq_regs(old_regs);
}

static DEFINE_SPINLOCK(sc_irq_lock);
static int sc_irq_refcount;

void service_subclass_irq_register(void)
{
	spin_lock(&sc_irq_lock);
	if (!sc_irq_refcount)
		ctl_set_bit(0, 9);
	sc_irq_refcount++;
	spin_unlock(&sc_irq_lock);
}
EXPORT_SYMBOL(service_subclass_irq_register);

void service_subclass_irq_unregister(void)
{
	spin_lock(&sc_irq_lock);
	sc_irq_refcount--;
	if (!sc_irq_refcount)
		ctl_clear_bit(0, 9);
	spin_unlock(&sc_irq_lock);
}
EXPORT_SYMBOL(service_subclass_irq_unregister);