Pi Support Strategy?

[mtx2d]

Dear Team,
Thanks for sharing this amazing project!
Was wondering if this project can be extended to run on a Raspberry-Pi?

If we think it a good idea, could the team please share some guidance on what might be important milestones to supporting Pi?

With a high level roadmap, I (or other ppl with same interest) can chip off the work and eventually we can have this OS running on Pis.

What do we think?

[wangrunji0408]

Thanks for your interest!

The official Zircon kernel supports ARM64 and was able to run on Raspi3.
Currently our implementation only supports x86_64, but ARM64 and Raspi is in the plan.
Fortunately we have similar experience before on the rCore project. So I believe the Raspi support will come soon :)

Actually it's not hard to support a new ISA or platform. zCore has a hardware abstraction layer to isolate architecture-dependent code. We only need to check the code on kernel-hal-bare crate, and give another implementation for aarch64. And this crate is more like a wrapper of other low-level crates, e.g. x86_64 and aarch64, which provides arch-specific registers and page table operations. Another important dependency of HAL is trapframe-rs, which is used for switching between kernel and user space, handling interrupt and exceptions. We also need to port it to aarch64.

To summary, a high-level roadmap to Raspi might like this:

• Construct a minimal kernel on Raspi (continue to use embedded booting from rCore or explore a new UEFI solution).
• Port kernel-hal-bare to aarch64.
• Port trapframe-rs to aarch64.

Once we have any progress on this topic, we will share them below.
Any other ideas or comments are welcome!

[tlightsky]

also interested in run zCore on my Respi Zero W/Respi 3

[wangrunji0408]

First step completed:

We have ported trapframe-rs to aarch64.
Now Zircon libos can basically run on ARM64 Linux!

See #78

[YdrMaster]

Thanks to 国防科大, aarch64 is supported since #306.