arch/i386/oprofile/nmi_timer_int.c


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

/**
 * @file nmi_timer_int.c
 *
 * @remark Copyright 2003 OProfile authors
 * @remark Read the file COPYING
 *
 * @author Zwane Mwaikambo <zwane@linuxpower.ca>
 */

#include <linux/init.h>
#include <linux/smp.h>
#include <linux/errno.h>
#include <linux/oprofile.h>
#include <linux/rcupdate.h>


#include <asm/nmi.h>
#include <asm/apic.h>
#include <asm/ptrace.h>
 
static int nmi_timer_callback(struct pt_regs * regs, int cpu)
{
	oprofile_add_sample(regs, 0);
	return 1;
}

static int timer_start(void)
{
	disable_timer_nmi_watchdog();
	set_nmi_callback(nmi_timer_callback);
	return 0;
}


static void timer_stop(void)
{
	enable_timer_nmi_watchdog();
	unset_nmi_callback();
	synchronize_sched();  /* Allow already-started NMIs to complete. */
}


int __init op_nmi_timer_init(struct oprofile_operations * ops)
{
	if (atomic_read(&nmi_active) <= 0)
		return -ENODEV;

	ops->start = timer_start;
	ops->stop = timer_stop;
	ops->cpu_type = "timer";
	printk(KERN_INFO "oprofile: using NMI timer interrupt.\n");
	return 0;
}