No HW RNG on general purpose Graviton Instances. WHY?

Graviton 2 doesn't support h/w RNG instructions. Graviton 3 does. We have it listed here: https://github.com/aws/aws-graviton-getting-started

Well, apparently t4g is powered by Graviton 2 and c7g Graviton 3. Their respective arch are ARMv8.2-A and ARMv8.4-A. But RNDR has been introduced with ARMv8.5-A. Either this wiki article is wrong or Graviton processors are brewed with extra stuff.

Either way, Graviton 2 instances are left with no HW RNG.

But RNDR has been introduced with ARMv8.5-A. Either this wiki article is wrong or Graviton processors are brewed with extra stuff.

Graviton3 is based on Arm's Neoverse-V1 core which implements everything needed for Armv8.4-a plus some extras they pulled in from Armv8.5-a, such as the TRNG instructions. You can see the full list of features from the Tech Reference Manual for the V1 core. Its not uncommon for Arm when building core IP to have a base architecture it fully supports yet pull in bits of future architectures as needed due to customer needs. For what Graviton supports, consider https://github.com/aws/aws-graviton-getting-started the definitive guide, and please raise issues if something appears missing.