Commit 7d3d897a authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt
Browse files

powerpc/hvc_udbg: Don't crash when udbg_putc is NULL 



Also while at it, add some help text indicating why you shouldn't
enable that driver under normal circumstances

Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent ba7a4822

drivers/tty/hvc/Kconfig

+4 −0
Original line number Diff line number Diff line
@@ -71,6 +71,10 @@ config HVC_UDBG 
       depends on PPC && EXPERIMENTAL

       select HVC_DRIVER

       default n

       help

         This is meant to be used during HW bring up or debugging when

	 no other console mechanism exist but udbg, to get you a quick

	 console for userspace. Do NOT enable in production kernels. 



config HVC_DCC

       bool "ARM JTAG DCC console"

drivers/tty/hvc/hvc_udbg.c

+7 −1
Original line number Diff line number Diff line
@@ -36,7 +36,7 @@ static int hvc_udbg_put(uint32_t vtermno, const char *buf, int count) 
{

	int i;



	for (i = 0; i < count; i++)

	for (i = 0; i < count && udbg_putc; i++)

		udbg_putc(buf[i]);



	return i;
@@ -67,6 +67,9 @@ static int __init hvc_udbg_init(void) 
{

	struct hvc_struct *hp;



	if (!udbg_putc)

		return -ENODEV;



	BUG_ON(hvc_udbg_dev);



	hp = hvc_alloc(0, NO_IRQ, &hvc_udbg_ops, 16);
@@ -88,6 +91,9 @@ module_exit(hvc_udbg_exit); 


static int __init hvc_udbg_console_init(void)

{

	if (!udbg_putc)

		return -ENODEV;



	hvc_instantiate(0, 0, &hvc_udbg_ops);

	add_preferred_console("hvc", 0, NULL);