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-rw-r--r--Documentation/DocBook/kgdb.tmpl17
-rw-r--r--kernel/debug/debug_core.c16
2 files changed, 33 insertions, 0 deletions
diff --git a/Documentation/DocBook/kgdb.tmpl b/Documentation/DocBook/kgdb.tmpl
index d71b57fcf116..4ee4ba3509fc 100644
--- a/Documentation/DocBook/kgdb.tmpl
+++ b/Documentation/DocBook/kgdb.tmpl
@@ -362,6 +362,23 @@
</para>
</para>
</sect1>
+ <sect1 id="kgdbreboot">
+ <title>Run time parameter: kgdbreboot</title>
+ <para> The kgdbreboot feature allows you to change how the debugger
+ deals with the reboot notification. You have 3 choices for the
+ behavior. The default behavior is always set to 0.</para>
+ <orderedlist>
+ <listitem><para>echo -1 > /sys/module/debug_core/parameters/kgdbreboot</para>
+ <para>Ignore the reboot notification entirely.</para>
+ </listitem>
+ <listitem><para>echo 0 > /sys/module/debug_core/parameters/kgdbreboot</para>
+ <para>Send the detach message to any attached debugger client.</para>
+ </listitem>
+ <listitem><para>echo 1 > /sys/module/debug_core/parameters/kgdbreboot</para>
+ <para>Enter the debugger on reboot notify.</para>
+ </listitem>
+ </orderedlist>
+ </sect1>
</chapter>
<chapter id="usingKDB">
<title>Using kdb</title>
diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index 3c1ad4e03543..3f88a45e6f0a 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -76,6 +76,8 @@ static int exception_level;
struct kgdb_io *dbg_io_ops;
static DEFINE_SPINLOCK(kgdb_registration_lock);
+/* Action for the reboot notifiter, a global allow kdb to change it */
+static int kgdbreboot;
/* kgdb console driver is loaded */
static int kgdb_con_registered;
/* determine if kgdb console output should be used */
@@ -97,6 +99,7 @@ static int __init opt_kgdb_con(char *str)
early_param("kgdbcon", opt_kgdb_con);
module_param(kgdb_use_con, int, 0644);
+module_param(kgdbreboot, int, 0644);
/*
* Holds information about breakpoints in a kernel. These breakpoints are
@@ -788,8 +791,21 @@ void __init dbg_late_init(void)
static int
dbg_notify_reboot(struct notifier_block *this, unsigned long code, void *x)
{
+ /*
+ * Take the following action on reboot notify depending on value:
+ * 1 == Enter debugger
+ * 0 == [the default] detatch debug client
+ * -1 == Do nothing... and use this until the board resets
+ */
+ switch (kgdbreboot) {
+ case 1:
+ kgdb_breakpoint();
+ case -1:
+ goto done;
+ }
if (!dbg_kdb_mode)
gdbstub_exit(code);
+done:
return NOTIFY_DONE;
}