LinuxCNC on non-backdoored hardware - what are the options?

Hello, 
I would like to install LinuxCNC on multiple machines for a secure project.

We cannot use backdoored CPUs. Therefore, all Intel and AMD processors post-2005 are unusable for our manufacturing project. This is on account of the chip-on-chip surveillance engines present in almost all post-2005 CPU hardware (IME on Intel / PSP on AMD).

Because of this problem, we have plans to design our CNC-router and robot-arm control systems based on PowerPC970 chips. We can repurpose these from G5 PowerMacs. I have now been tasked with researching different software we can use on these secure CPUs, rather than writing our own from scratch.

I like the look of LinuxCNC.

I understand that LinuxCNC runs using the RTAI (Realtime Application Interface) patch. I can see on the RTAI site that older versions of RTAI supported PowerPC. Does anyone here know what the latest version of RTAI to support PowerPC / secure CPUs was?

Is anyone here running LinuxCNC on secure hardware, or are most LinuxCNC systems based on these newer backdoored-chip architectures?

Alternatively, I'm also considering reverting to m68k processors, as they are also secure, and were supported by RTAI. We would prefer, however, to use the PowerPC970x series, as these are the fastest available chips currently available in volume (on the second-hand market) for those who wish to build a secure manufacturing system without surveillance backdoors.

Obviously, we could air-gap our manufacturing systems and just use the compromised post-2005 hardware, but we would like our manufacturing systems to be operable remotely.

I'd love to hear from anyone who has bulit a secure LinuxCNC system using PowerPC or m68k hardware. Thanks!

I'm not an expert on hardware security, but Purism appears to offer an IME-disabled computer:

puri.sm/products/librem-mini/


A quick internet search revealed a few other vendors as well.  You may not be stuck with old hardware.

 

Thank you for this suggestion. I looked into Purism and had a short conversation with them. The problem is that Purism have yet to offer a non-backdoored system, as their roadmap is incomplete.

Purism are working backwards to fix compromised hardware.
We'd like to begin secure.

To use a metaphor: We want to build a safe LinuxCNC-based 'swimming pool' for our engineers to 'swim in' as they work. Purism offer the (yet-to-be-reached) goal of muzzling the 'shark' (IME / PSP) in the water. But we'd prefer a pool which never had a 'shark' in to begin with 

Hope this makes sense.

It may be simpler to use a RT-Preempt kernel than RTAI

Thanks for the suggestion to look at an a RT-Preempt kernel.
I will investigate this option.

Let's get one thing out of the way:
I am a highly paranoid computer user with a lifetime of professional experience, still i have over 10 PC's on 24h, all running Linux, and i am fully aware of the amount of data they send ....
So i do understand what you are trying to achieve, but using old hardware implies using old software, and that poses a security risk as they might not broadcast data but might get hacked into by using vulnerabilities inherent in them.
On the other side, a bit of effort usually proves fruitful by choosing new-ish software with lite GUI/DE and forcing it to work on older systems, did that a lot several years back, still have a HP thin client with Geode 1GHz processor running LinuxCNC 2.7 nicely.
Questions:
-are you designing new boards or using existing?
-by 68k you mean 68000 Motorola processors?
-how about using pre 2005 Xeon workstations?
Answers (maybe):
-search for Debian Dog LinuxCNC, over 200MB ISO ready for use, should run on pretty much anything from PIII@700MHz
-search for coolcnc iso, over 50MB ISO ready for use, should run on anything from PII@300MHz
-using new Debian with lite Desktop environment works on quite old systems, Core2 for sure works nicely
-having a go at installing RT kernel and LinuxCNC on Porteus Linux is also an option as that is still updated and maintained and is extremely lite and very low on resources.