kgdboc: Add ekgdboc for early use of the kernel debugger

The ekgdboc= differs from kgdboc= in that you can begin debuggin as
soon as the exceptions are setup and the kgdb I/O driver is available,
instead of waiting until the tty subsystem is available.

CC: kgdb-bugreport@lists.sourceforge.net
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/drivers/serial/kgdboc.c b/drivers/serial/kgdboc.c
index b765ab48dfe7..a9a94ae72349 100644
--- a/drivers/serial/kgdboc.c
+++ b/drivers/serial/kgdboc.c
@@ -223,6 +223,25 @@ static struct kgdb_io kgdboc_io_ops = {
 	.post_exception		= kgdboc_post_exp_handler,
 };
 
+#ifdef CONFIG_KGDB_SERIAL_CONSOLE
+/* This is only available if kgdboc is a built in for early debugging */
+int __init kgdboc_early_init(char *opt)
+{
+	/* save the first character of the config string because the
+	 * init routine can destroy it.
+	 */
+	char save_ch;
+
+	kgdboc_option_setup(opt);
+	save_ch = config[0];
+	init_kgdboc();
+	config[0] = save_ch;
+	return 0;
+}
+
+early_param("ekgdboc", kgdboc_early_init);
+#endif /* CONFIG_KGDB_SERIAL_CONSOLE */
+
 module_init(init_kgdboc);
 module_exit(cleanup_kgdboc);
 module_param_call(kgdboc, param_set_kgdboc_var, param_get_string, &kps, 0644);