Rust Kernel Support On AArch64 Ready To Go For Linux 6.9

The 64-bit Arm (AArch64) little-endian kernel will be ready to support the Rust kernel code with the upcoming Linux 6.9 cycle.

Queued in the ARM64 development tree via "next/rust-for-arm64" is the patch to get the Rust ARM64/AArch64 support for the Rust kernel code over the finish line. The commit notes:

"This commit provides the build flags for Rust for AArch64. The core Rust support already in the kernel does the rest. This enables the PAC ret and BTI options in the Rust build flags to match the options that are used when building C.

The Rust samples have been tested with this commit."

AArch64 is now the latest architecture following x86_64 (and x86_64 user-mode Linux "um") and LoongArch to support Rust in the Linux kernel.

So far much of the Rust for the Linux kernel enablement has been about getting the infrastructure in place, including various sample code. With Linux 6.8 there is now a Rust-written network PHY driver although it's a port from an existing C driver. The Rust Apple Silicon SGX DRM driver remains on the way as well as other Rust kernel drivers to come.