Some problems with the libbsd update

[Sebastian Huber]

On 23/08/18 01:00, Chris Johns wrote:
> On 22/08/2018 22:25, Sebastian Huber wrote:
>> On 22/08/18 14:06, Joel Sherrill wrote:
>>> On Wed, Aug 22, 2018, 6:47 AM Sebastian Huber
>>> <sebastian.huber at embedded-brains.de
>>> <mailto:sebastian.huber at embedded-brains.de>> wrote:
>>>
>>> It really is necessary to know how the other architectures implement it. Some
>>> may turn out to be easy. Others like Epiphany and new may never matter.
>> If the niche architectures don't use libbsd (which I guess is the case), then
>> there is no issue at all.
>>
> Do we document what is supported and what is not supported?

The status of the SMP and TLS support is documented in the CPU Supplement.

We added the TLS support for ARM, m68k, PowerPC and SPARC in January 
2014 and also recently for RISC-V. TLS is a C11 standard element. All 
RTEMS architectures which don't support it have a maintainer problem 
from my point of view.

>
> Does libbsd have suitable checks on the built RTEMS to know it cannot be supported?

One way to figure out if it basically works is to run the tests.

>
> FWIW I do not think the idea of "one size fits all" is workable. I think a
> number of architectures would benefit from a different smaller networking stack.

libbsd is not only a network stack. It contains also USB and MMC card 
support. I work on a port of the NVMe support currently.

FreeBSD seems to receive a huge funding from CDN providers such as 
Netfix and Limelight Networks. They probably don't care about 
uni-processor system support at all. The use of lock-free data 
structures (Concurrency Kit) and the epoch memory reclamation are now a 
mandatory infrastructure. There is no FreeBSD configuration option to 
avoid this. This was a bit surprising to me. It was also introduced less 
than half a year before the planned FreeBSD 12 release.

The recent changes in FreeBSD make the lwIP network stack even more 
attractive for low-end targets.

-- 
Sebastian Huber, embedded brains GmbH

Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone   : +49 89 189 47 41-16
Fax     : +49 89 189 47 41-09
E-Mail  : sebastian.huber at embedded-brains.de
PGP     : Public key available on request.

Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.