um: add earlyprintk support
User Mode Linux can also benefit from earlyprintk. UML's earlyprintk
writes kernel messages directly to stdout.
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/um/Kconfig.debug b/arch/um/Kconfig.debug
index 8fce5e5..85c86edd 100644
--- a/arch/um/Kconfig.debug
+++ b/arch/um/Kconfig.debug
@@ -37,4 +37,14 @@
stack seen so far.
This option will slow down process creation and destruction somewhat.
+
+config EARLY_PRINTK
+ bool "Early printk"
+ default y
+ ---help---
+ Write kernel log output directly to stdout.
+
+ This is useful for kernel debugging when your machine crashes very
+ early before the console code is initialized.
+
endmenu
