1 /**
2 * @file nmi_timer_int.c
3 *
4 * @remark Copyright 2003 OProfile authors
5 * @remark Read the file COPYING
6 *
7 * @author Zwane Mwaikambo <zwane@linuxpower.ca>
8 */
9
10 #include <linux/init.h>
11 #include <linux/smp.h>
12 #include <linux/errno.h>
13 #include <linux/oprofile.h>
14 #include <linux/rcupdate.h>
15 #include <linux/kdebug.h>
16
17 #include <asm/nmi.h>
18 #include <asm/apic.h>
19 #include <asm/ptrace.h>
20
21 static int profile_timer_exceptions_notify(struct notifier_block *self,
22 unsigned long val, void *data)
23 {
24 struct die_args *args = (struct die_args *)data;
25 int ret = NOTIFY_DONE;
26
27 switch (val) {
28 case DIE_NMI:
29 oprofile_add_sample(args->regs, 0);
30 ret = NOTIFY_STOP;
31 break;
32 default:
33 break;
34 }
35 return ret;
36 }
37
38 static struct notifier_block profile_timer_exceptions_nb = {
39 .notifier_call = profile_timer_exceptions_notify,
40 .next = NULL,
41 .priority = 0
42 };
43
44 static int timer_start(void)
45 {
46 if (register_die_notifier(&profile_timer_exceptions_nb))
47 return 1;
48 return 0;
49 }
50
51
52 static void timer_stop(void)
53 {
54 unregister_die_notifier(&profile_timer_exceptions_nb);
55 synchronize_sched(); /* Allow already-started NMIs to complete. */
56 }
57
58
59 int __init op_nmi_timer_init(struct oprofile_operations *ops)
60 {
61 if ((nmi_watchdog != NMI_IO_APIC) || (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 NMI timer interrupt.\n");
68 return 0;
69 }
70
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