Updating rpi5-kernel

[dvergeylen]

Hi!

The kernel referenced by the rpi5-kernel (and rpi-kernel) template(s) is the 6.6.78 from the Raspberry Pi foundation at this time of writing. I would like to help upgrading it to a more recent version (6.12.y, the current LTS, in sync with mainline, see 4661a42d from 3 days ago), paving the way for the next 6.18 LTS version expected end of this year.

As I was updating the template file and preparing a PR submit, I found myself struggling with the kernel options chosen for the pi. I could not find on which base the arm64 defconfig configuration options are chosen. Is there a policy on how the new KConfig options are selected? On which base? Are specific options required for Void to run?

For the specific case of the Rpi5, the bcm2712_defconfig provided by the foundation sounds a reasonable choice and is even a possibility in the template file, although never met (there is always a arm64-dotconfig file in srcpkgs/rpi5-kernel/files, so the else path is never taken). The only option missing is CONFIG_MODULE_SIG (and friends) to build, which could go to an overlay.

Wouldn't it be a better choice to preferably take the bcm2712_defconfig from downstream as base and add the Void specific KConfig options as an overlay? This would ease the maintenance as the board specific KConfig options selection burden would be delegated to the Foundation. This will be even more relevant for 6.18+, as the RPi5 is now supported mainline (at least, the RP1 chip, which communicates with the peripherals) and the board specific support options have changed.

I have a RPi 5 and a RPi400 available to test multiple configurations and would be more than happy to do so.

[classabbyamp]

the defconfigs are extremely lacking compared to some of the features we enable on our mainline linuxX.Y packages, so users that expect something to work one way on void (like filesystem support, scheduler, or hardening options) wouldn't be enabled. I went through and combined the things in the defconfigs with void's dotconfigs to come up with something closer to the default experience

as for 6.12, check out #56766. it's a bit of an undertaking so I don't always have time to update it and test it frequently.

[dvergeylen]

Thank you so much for your answer