From bec4d62ead8096e433d624d9339893f50badd992 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Mon, 19 Mar 2012 19:35:55 -0500 Subject: kgdb,debug_core: add the ability to control the reboot notifier Sometimes it is desirable to stop the kernel debugger before allowing a system to reboot either with kdb or kgdb. This patch adds the ability to turn the reboot notifier on and off or enter the debugger and stop kernel execution before rebooting. It is possible to change the setting after booting the kernel with the following: echo 1 > /sys/module/debug_core/parameters/kgdbreboot It is also possible to change this setting using kdb / kgdb to manipulate the variable directly. Using KDB: mm kgdbreboot 1 Using gdb: set kgdbreboot=1 Reported-by: Jan Kiszka Signed-off-by: Jason Wessel --- kernel/debug/debug_core.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'kernel/debug') 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; } -- cgit v1.2.3-70-g09d2