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Jonathan Brouwer
dc103c4cd9
RISC-V: Implement (Zkne or Zknd) intrinsics correctly On rust-lang/stdarch#1765, it has been pointed out that two RISC-V (64-bit only) intrinsics to perform AES key scheduling have wrong target feature. `aes64ks1i` and `aes64ks2` instructions require *either* Zkne (scalar cryptography: AES encryption) or Zknd (scalar cryptography: AES decryption) extension (or both) but corresponding Rust intrinsics (in `core::arch::riscv64`) required *both* Zkne and Zknd extensions. An excerpt from the original intrinsics: ```rust #[target_feature(enable = "zkne", enable = "zknd")] ``` To fix that, we need to: 1. Represent a condition where *either* Zkne or Zknd is available and 2. Workaround an issue: `llvm.riscv.aes64ks1i` / `llvm.riscv.aes64ks2` LLVM intrinsics require either Zkne or Zknd extension. This PR attempts to resolve them by: 1. Adding a perma-unstable RISC-V target feature: `zkne_or_zknd` (implied from both `zkne` and `zknd`) and 2. Using inline assembly to construct machine code directly (because `zkne_or_zknd` alone cannot imply neither Zkne nor Zknd, we cannot use LLVM intrinsics). The author confirmed that we can construct an AES key scheduling function with decent performance using fixed `aes64ks1i` and `aes64ks2` intrinsics (with optimization enabled).
stdarch - Rust's standard library SIMD components
This repository contains the core_arch crate, which implements core::arch - Rust's core library architecture-specific intrinsics.
The std::simd component now lives in the
packed_simd_2 crate.
Synchronizing josh subtree with rustc
This repository is linked to rust-lang/rust as a josh subtree. You can use the rustc-josh-sync tool to perform synchronization.
You can find a guide on how to perform the synchronization here.