Linux Kernel  3.7.1
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nmi_debug.c
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1 /*
2  * Copyright (C) 2007 Atmel Corporation
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  */
8 #include <linux/delay.h>
9 #include <linux/kdebug.h>
10 #include <linux/notifier.h>
11 #include <linux/sched.h>
12 #include <linux/hardirq.h>
13 
14 enum nmi_action {
15  NMI_SHOW_STATE = 1 << 0,
16  NMI_SHOW_REGS = 1 << 1,
17  NMI_DIE = 1 << 2,
18  NMI_DEBOUNCE = 1 << 3,
19 };
20 
21 static unsigned long nmi_actions;
22 
23 static int nmi_debug_notify(struct notifier_block *self,
24  unsigned long val, void *data)
25 {
26  struct die_args *args = data;
27 
28  if (likely(val != DIE_NMI))
29  return NOTIFY_DONE;
30 
31  if (nmi_actions & NMI_SHOW_STATE)
32  show_state();
33  if (nmi_actions & NMI_SHOW_REGS)
34  show_regs(args->regs);
35  if (nmi_actions & NMI_DEBOUNCE)
36  mdelay(10);
37  if (nmi_actions & NMI_DIE)
38  return NOTIFY_BAD;
39 
40  return NOTIFY_OK;
41 }
42 
43 static struct notifier_block nmi_debug_nb = {
44  .notifier_call = nmi_debug_notify,
45 };
46 
47 static int __init nmi_debug_setup(char *str)
48 {
49  char *p, *sep;
50 
51  register_die_notifier(&nmi_debug_nb);
52 
53  if (*str != '=')
54  return 0;
55 
56  for (p = str + 1; *p; p = sep + 1) {
57  sep = strchr(p, ',');
58  if (sep)
59  *sep = 0;
60  if (strcmp(p, "state") == 0)
61  nmi_actions |= NMI_SHOW_STATE;
62  else if (strcmp(p, "regs") == 0)
63  nmi_actions |= NMI_SHOW_REGS;
64  else if (strcmp(p, "debounce") == 0)
65  nmi_actions |= NMI_DEBOUNCE;
66  else if (strcmp(p, "die") == 0)
67  nmi_actions |= NMI_DIE;
68  else
69  printk(KERN_WARNING "NMI: Unrecognized action `%s'\n",
70  p);
71  if (!sep)
72  break;
73  }
74 
75  return 0;
76 }
77 __setup("nmi_debug", nmi_debug_setup);