2 files changed, 33 insertions, 0 deletions

diff --git a/Documentation/DocBook/kgdb.tmpl b/Documentation/DocBook/kgdb.tmpl
index d71b57fcf11..4ee4ba3509f 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 3c1ad4e0354..3f88a45e6f0 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;
 }