Sven Peter who remains one of the very active Asahi Linux developers and working on upstreaming various elements of Apple Silicon support for the Linux kernel has sent up warning flares around the eventual Apple M4 support.
Sven Peter posted on Mastodon this morning that it looks like the Apple M4 hardware enablement for Linux will be a “rather painful” affair due to changes compared to the Apple M1/M2 handling.
Sven Peter posted:
“Looks like M4 support for #asahilinux is going be rather painful. We’re still focusing on upstreaming M1/M2 support but other people have been trying to bring up m1n1 on M4 and it looks like a few things changed:
When configuring a macho boot object we now get dropped into an environment where Apple’s SPTM is running in GL2 and we are supposed to talk to it from EL2 with MMU already enabled to setup pagetables. This neither works for Linux nor for running XNU under our hypervisor to reverse engineer the new hardware.
When configuring a raw boot object we’re dropped into EL2 with GL2 and most (all?) Apple specific extensions disabled. This is totally fine for Linux but we can’t run XNU under our hypervisor that we use to reverse engineer the hardware in this state. This also seems to be broken for >=15.2 right now because it probably isn’t very well tested :/”
This is unfortunate to hear and will likely result in an even lengthier bring-up time for Apple M4 on Linux. As their focus for now continues to be on getting all of the Apple M1 and M2 hardware support bits completed and upstreamed, don’t hold your breath on the Apple M4 (and M3) support on the near-term especially with these latest roadblocks. In any event we’ll be eagerly watching to see what unfolds for Apple M4 hardware support on Linux.
