Hector Martin

xbox one x has special circuits to prevent signal lines glitching

Yes, Microsoft is the only console manufacturer right now who knows what they're doing ;)

mm very heavily low-pass filtered I'd imagine. Not hard to do real glitch-attack detection but would be tradeoff with false triggers from regular pwr rail power noise. Seems very doable tho

Glitch detection is not a simple thing, especially on voltage rails. Clock glitch detection means you're sacrificing 10-20% of performance because you have to close timing at a higher frequency. Reset glitch monitoring is fairly trivial (synchronize/buffer the input).

Well, the idea is that typically the code that needs performance isn't the security code. So if you can compartmentalize properly... Of course if both run on the same CPU that's still prone to microarchitectural nastygrams unless designed to basically reset on priv transitions.

More realistically you just put all the security into a separate CPU and harden it as much as possible.