1/**
2 * @file init.c
3 *
4 * @remark Copyright 2002 OProfile authors
5 * @remark Read the file COPYING
6 *
7 * @author John Levon <levon@movementarian.org>
8 */
9
10#include <linux/kernel.h>
11#include <linux/oprofile.h>
12#include <linux/errno.h>
13#include <linux/init.h>
14#include <linux/param.h>	/* for HZ */
15
16#ifdef CONFIG_SPARC64
17#include <linux/notifier.h>
18#include <linux/rcupdate.h>
19#include <linux/kdebug.h>
20#include <asm/nmi.h>
21
22static int profile_timer_exceptions_notify(struct notifier_block *self,
23					   unsigned long val, void *data)
24{
25	struct die_args *args = data;
26	int ret = NOTIFY_DONE;
27
28	switch (val) {
29	case DIE_NMI:
30		oprofile_add_sample(args->regs, 0);
31		ret = NOTIFY_STOP;
32		break;
33	default:
34		break;
35	}
36	return ret;
37}
38
39static struct notifier_block profile_timer_exceptions_nb = {
40	.notifier_call	= profile_timer_exceptions_notify,
41};
42
43static int timer_start(void)
44{
45	if (register_die_notifier(&profile_timer_exceptions_nb))
46		return 1;
47	nmi_adjust_hz(HZ);
48	return 0;
49}
50
51
52static void timer_stop(void)
53{
54	nmi_adjust_hz(1);
55	unregister_die_notifier(&profile_timer_exceptions_nb);
56	synchronize_sched();  /* Allow already-started NMIs to complete. */
57}
58
59static int op_nmi_timer_init(struct oprofile_operations *ops)
60{
61	if (atomic_read(&nmi_active) <= 0)
62		return -ENODEV;
63
64	ops->start = timer_start;
65	ops->stop = timer_stop;
66	ops->cpu_type = "timer";
67	printk(KERN_INFO "oprofile: Using perfctr NMI timer interrupt.\n");
68	return 0;
69}
70#endif
71
72int __init oprofile_arch_init(struct oprofile_operations *ops)
73{
74	int ret = -ENODEV;
75
76#ifdef CONFIG_SPARC64
77	ret = op_nmi_timer_init(ops);
78	if (!ret)
79		return ret;
80#endif
81
82	return ret;
83}
84
85void oprofile_arch_exit(void)
86{
87}
88