x86, setup: Early-boot serial I/O support

This patch adds serial I/O support to the real-mode setup (very early
boot) printf(). It's useful for debugging boot code when running Linux
under KVM, for example. The actual code was lifted from early printk.

Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
LKML-Reference: <1278835617-11368-1-git-send-email-penberg@cs.helsinki.fi>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/arch/x86/boot/main.c b/arch/x86/boot/main.c
index 140172b895bd..4ef1a33e8572 100644
--- a/arch/x86/boot/main.c
+++ b/arch/x86/boot/main.c
@@ -130,6 +130,9 @@ void main(void)
         /* First, copy the boot header into the "zeropage" */
         copy_boot_params();
 
+        /* Initialize the early-boot console */
+        console_init();
+
         /* End of heap check */
         init_heap();