libbsd network on an mvme2500

Chandler, Brendan bchandler at
Tue Aug 17 19:19:37 UTC 2021

I think I found the answer to my own issue.  I needed this configuration option:

With that, the error "cannot create extension" goes away and I can boot.

From: Chandler, Brendan <bchandler at>
Sent: Tuesday, August 17, 2021 11:09
To: users at
Subject: libbsd network on an mvme2500

Hi rtems-users,

I'm trying to set up a simple RTEMS 5 program to get my mvme2500 board up and running with a static network configuration using libbsd.  I took the hello.c example from the getting started guide, and modified it to use libbsd and configure the network.  My problem is I get a runtime error when loading my binary when I call rtems_bsd_initialize():

## Booting kernel from Legacy Image at 10000000 ...
   Image Name:   RTEMS
   Created:      2021-08-17  15:32:55 UTC
   Image Type:   PowerPC Linux Kernel Image (gzip compressed)
   Data Size:    968695 Bytes = 946 KiB
   Load Address: 00004000
   Entry Point:  00004000
   Verifying Checksum ... OK
## Flattened Device Tree blob at 20000000
   Booting using the fdt blob at 0x20000000
   Uncompressing Kernel Image ... OK
   Loading Device Tree to 00ff9000, end 00fff04a ... OK
emerg: rtems_bsd_threads_init_early: cannot create extension

This seems to be coming from rtems-libbsd/rtemsbsd/rtems/rtems-kernel-thread.c where the call to rtems_extension_create() fails.

I've posted my code at github here:

Can anyone help get around this error?  I'm probably missing some configuration or setup, but haven't been able to determine what it is.

Thanks in advance for any help,

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