Nova without Bender

Alexander Boettcher alexander.boettcher at ...1...
Fri Aug 4 09:06:33 CEST 2017


On 03.08.2017 13:11, Johannes Kliemann wrote:
> I tried to use Nova without Bender with Multiboot2. Basically it works,
> but when I omit Bender, there's no serial output from either Nova or
> Genode. I couldn't find out what Bender does different to enable serial
> on Nova.

the task of Bender is to relocate modules to higher physical memory and
to detect PCI serial cards and determine the I/O ports to use them
actually. Bender writes this information to a area called Bios Data Area

The NOVA microhypervisor and 'core' of Genode look into this area and
use the information obtained from there to program and to drive the
UART/serial device.

By removing Bender, you effectively have no valid information in the BDA
anymore, and so you don't get any serial output.

> What is missing to enable serial on Nova alone?

If you don't want to use Bender, but want to have serial output, then
you have to hardcode the I/O ports for your target machine specifically
in the sources of NOVA and 'core', see [0] and [1].


> PS: It also seems that Benders Multiboot2-header [1] is not
> specification conform. The tags type and flags are defined as double
> word but according to the specification [2] these are u16 so this should
> be a word only.

You're right, I'm going to change it. Thanks!



Alexander Boettcher
Genode Labs -

Genode Labs GmbH - Amtsgericht Dresden - HRB 28424 - Sitz Dresden
Geschäftsführer: Dr.-Ing. Norman Feske, Christian Helmuth

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