Enable CONFIG_RUST on 7.x.x-bone Kernels

[thomas7475]

Hello,

Thanks for your great work maintaining the BeagleBoard kernels!

I recently set up bcachefs dkms 1 on my BeagleBone Black. However, as the filesystem continues to develop, upcoming versions will require the Linux kernel's Rust infrastructure.
To ensure the BBB remains compatible with upcoming bcachefs releases, would you be open to enabling CONFIG_RUST=y in the configs for the 7.x.x Kernel series?"

Regards.

[RobertCNelson]

Hi @thomas7475 actually yeah, now is a great time to re-add CONFIG_RUST=y my initial hesitation and you've might have seen this in the log, was testing RUST and disabling.. The major reason, i like to keep a unified config for all builds.. And Bookworm's 12.x rust is 1.63.0 which is too old. Well... As of July 11th... Bookworm 12.x is done https://www.debian.org/News/2026/2026071102 ... This means 6.18.x is really my last lts for 12.x (i won't bother with 6.18.x-lts + 1, as i'm moving from Debian 12/13 -> Debian 13/14 in all my nodes..)

Right now https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/Documentation/process/changes.rst?h=v7.2-rc1 shows 1.85.0 so we are golden for Debian 13+ right

(side note, now that Debian 12.x is done, i'm also done with Ubuntu Noble 24.04 ..)

Therefor

[thomas7475]

Hi @RobertCNelson i tested the latest 7.2.0-rc3-bone3 build and confirmed that CONFIG_RUST=y is enabled as expected. I'm not sure if you're the right person to direct this to, but I've run into a new issue: the linux-headers-7.2.0-rc3-bone3 package installed via apt is missing all the necessary Rust artifacts. Without them, building a DKMS module that depends on Rust is currently not possible.

a /usr/src/linux-headers-$(uname -r)/rust
ls: cannot access '/usr/src/linux-headers-7.2.0-rc3-bone3/rust': No such file or directory

zgrep CONFIG_RUST /proc/config.gz
CONFIG_RUSTC_VERSION=108500
CONFIG_RUST_IS_AVAILABLE=y
CONFIG_RUSTC_LLVM_VERSION=190107
CONFIG_RUSTC_LLVM_MAJOR_VERSION=19
CONFIG_RUST=y
CONFIG_RUSTC_VERSION_TEXT="rustc 1.85.0 (4d91de4e4 2025-02-17) (built from a source tarball)"
CONFIG_RUST_FW_LOADER_ABSTRACTIONS=y
CONFIG_RUST_PHYLIB_ABSTRACTIONS=y
# CONFIG_RUST_BITMAP_HARDENED is not set
# CONFIG_RUST_DEBUG_ASSERTIONS is not set
CONFIG_RUST_OVERFLOW_CHECKS=y
# CONFIG_RUST_BUILD_ASSERT_ALLOW is not set

[RobertCNelson]

Looking at https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/scripts/package and kbuild https://lore.kernel.org/linux-kbuild/ list, nothing rust specific sticks out, yet..

Oh ubuntu... what did you do... https://discourse.ubuntu.com/t/ubuntu-kernel-is-getting-rusty-in-lunar/34977

   linux-lib-rust-`uname -r` \
   linux-headers-`uname -r`

https://lists.ubuntu.com/archives/kernel-team/2023-May/139459.html

I see a basic start here: https://lore.kernel.org/linux-kbuild/20260714125259.78824-1-litvindev@gmail.com/

[thomas7475]

Hi @RobertCNelson I searched for a linux-lib-rust-* package in the standard repos but couldn’t find one. Is there a separate location for it, or is it provided by another package?

apt-cache search "^linux-headers-$(uname -r)"
linux-headers-7.2.0-rc3-bone3 - Linux kernel headers for 7.2.0-rc3-bone3 on armhf
t@BeagleBone:~$ apt list "linux-lib-rust-$(uname -r)"
t@BeagleBone:~$ apt search linux-lib-rust-$(uname -r)
t@BeagleBone:~$ apt search linux-lib-$(uname -r)
t@BeagleBone:~$ apt search linux-lib$(uname -r)
t@BeagleBone:~$ apt search linux-librust$(uname -r)

[RobertCNelson]

No... linux-lib-rust- is a custom patch ubuntu added to their tree.. Looks like first, https://lore.kernel.org/linux-kbuild/20260714125259.78824-1-litvindev@gmail.com/ needs to be queue'ed up for mainline, then 2nd linux-headers output in linux's deb-pkg script needs to be patched with rust includes..

so a little bit of development kernel side first..