Comment by fulafel
3 years ago
In https://asahilinux.org/2022/03/asahi-linux-alpha-release/ it says that 4k pages work on the HW but 16k has tome advantages. Dropping 4k page size supporrt would imply a departure from arm architecture compatibility compatibility I think, it might have also nontechnical problems (ARM license).
The arm spec allows to have machines that implement any of 4KB, 16KB, or 64KB granules or any combination thereof. Apple shipped plenty of phone SoCs that didn’t support 4KB pages for the CPU (A9->A13).
Interesting - at first this didn't seem to be detailed in the popular (Wikipedia etc) or ARM web pages I could find but it seems it was about terminlogy, "translation granule" was the right one and then you can find mentions like "The granule sizes that a processor supports are IMPLEMENTATION DEFINED".