diff options
| author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2012-03-14 18:37:04 +1100 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2012-03-16 09:28:15 +1100 |
| commit | 7d3d897a4697e4ff746e5e82f116b2346ed28150 (patch) | |
| tree | 740b5a83f9d354edf255f44a6072a47ec1ff7ba0 /drivers/tty/hvc | |
| parent | ba7a4822b48fbc7afd6b567c18e316a03f46684d (diff) | |
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: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'drivers/tty/hvc')
| -rw-r--r-- | drivers/tty/hvc/Kconfig | 4 | ||||
| -rw-r--r-- | drivers/tty/hvc/hvc_udbg.c | 8 |
2 files changed, 11 insertions, 1 deletions
diff --git a/drivers/tty/hvc/Kconfig b/drivers/tty/hvc/Kconfig index 8ea7f078b233..48cb8d3d1758 100644 --- a/drivers/tty/hvc/Kconfig +++ b/drivers/tty/hvc/Kconfig @@ -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" diff --git a/drivers/tty/hvc/hvc_udbg.c b/drivers/tty/hvc/hvc_udbg.c index b0957e61a7be..2259c6e72f06 100644 --- a/drivers/tty/hvc/hvc_udbg.c +++ b/drivers/tty/hvc/hvc_udbg.c @@ -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); |