I can't figure out why there doesn't seem to be a commercial market for something like CHERI ( https://www.cl.cam.ac.uk/research/security/ctsrd/cheri/ ) ... even if it was considerably slower than top end CPUs there are plenty of applications that don't care (and find chips like arm a8 or atom fast enough) but where high security is paramount.

Maybe Intel still remembers the pain of iAXP 432 but that doesn't explain the rest of the industry.

ARM is doing CHERI-enhanced cores, at least as a research project: https://www.eetasia.com/news/article/CHERI-based-Prototype-t...

There's also Dover Microsystems, which is trying to commercialize similar-in-spirit processor extensions originally developed at Draper Labs.

Sadly yes, while ARM and SPARC bounds checking get used to tame C and its derived languages, Intel decides to retire MPX.

Apparently MPX had a number of issues in general that made it worse than tools like Address Sanitizer: https://arxiv.org/pdf/1702.00719.pdf

I know, but then the path forward would be to fix it, instead of dropping it on the floor without any plan going forward.

After all, SPARC ADI is used in production, and ARM as well (partially with iOS, enforced in future Android devices).

What feature does iOS have that that is similar to this?

Pointer authentication and hardened runtime.

Those don’t really catch memory safety issues in the general case; they’re more focused on exploit mitigation.

As far as I can tell, Intel MPX is like a hardware address sanitizer. This is a little different.