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 
profile_timer_exceptions_notify(struct notifier_block * self,unsigned long val,void * data)22 static 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 
39 static struct notifier_block profile_timer_exceptions_nb = {
40 	.notifier_call	= profile_timer_exceptions_notify,
41 };
42 
timer_start(void)43 static 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 
timer_stop(void)52 static void timer_stop(void)
53 {
54 	nmi_adjust_hz(1);
55 	unregister_die_notifier(&profile_timer_exceptions_nb);
56 	synchronize_rcu();  /* Allow already-started NMIs to complete. */
57 }
58 
op_nmi_timer_init(struct oprofile_operations * ops)59 static 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 
oprofile_arch_init(struct oprofile_operations * ops)72 int __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 
oprofile_arch_exit(void)85 void oprofile_arch_exit(void)
86 {
87 }
88