[coreboot] [PATCH] xcshell: serial shell for early debugging

Stefan Reinauer stepan at coresystems.de
Tue Jul 14 18:20:56 CEST 2009

On 14.07.2009 11:23 Uhr, Michael Gold wrote:
> I've been working on some code to ensure I can debug a system even if
> coreboot fails to boot an OS.  The attached patch adds this code to the
> tree:
>   - serialprobe watches the serial port for about a second, and boots
>     the system normally unless 32 consecutive null bytes are seen.
>   - xcshell allows the CPU to be controlled via the serial port, using
>     a binary protocol.
> The code assembles to about 1 KB, so it can be left in an image for
> emergency use.  It's also modular in case someone wants to use it with
> something other than a serial port.
> xcsinterp.inc describes the protocol, and xccmd.inc describes the
> command set.


out of curiosity..

Would it be possible to enhance the already existing "llshell" with your
features? I would want to prevent more than one assembler written shell
of this type floating around in the coreboot tree.

Best wishes,


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