Do most Intel (and by extension, Linux) machines have SHA2, though? I think it’s a pretty recent extension and at least initially, they were only shipping it in their low-end embedded models.
> I haven’t been able to buy a CPU that doesn’t have SHA2 acceleration for an number of years now.
This is incorrect. Intel only launched their 11th gen desktop processors March 30, 2021. The 10th gen and earlier desktop processors do not have the SHA instructions. You can still buy a new i9-10900k from Newegg today.
(Note that 10th gen Intel mobile/laptop processors are a different micro-architecture, and do support SHA.)
Edit: Perhaps you're thinking of the AES instructions? They've been around a lot longer.
The argument that not all CPUs running Linux have hardware SHA2 is valid, and therefore can't be assumed. However saying because one (even a significant one... though it's arguable it hasn't been the majority for a while) doesn't and therefore it shouldn't be used seems shortsighted at best. For decades various minority features have been enabled in the Linux kernel. Since when is lowest common denominator the desirable target to utilize exclusively?