use circular ring for IPI messages

[giacomogroppi]

Static allocation of messages via a circular queue still allows message delivery in FIFO order and reduces latency, since it does not use dynamic memory.

To enable this functionality, you need to set the IPI_STATIC_MEM define

[josecm]

Hello @giacomogroppi, thanks for this PR! I will be reviewing it in the coming weeks. We have been thinking about refactoring this code for a while, so the first thing I am thinking is to fully replacing the list-based message implementation with your circular queue, rather than keeping it as a compile-time option. That said, we need to weigh the pros and cons carefully before making a decision.

[giacomogroppi]

I modified the implementation by removing the version that uses the list. As for the pros and cons of this implementation, I’ve just finished my master’s thesis and I only have an RPi 3B+ available; if there’s anything I can do to help you, let me know!

[DavidMCerdeira]

Greetings @giacomogroppi

Taking a closer look at this, I'm getting a few errors when trying to compile for qemu-aarch64-virt using Arm GNU Toolchain 14.2.Rel1.

Please let me know your setup for successful compilation.
Additionally I'd appreciate if you could rebase this with Bao's main branch.

Thanks!

[giacomogroppi]

I build it using

export CROSS_COMPILE=aarch64-none-elf-
make PLATFORM=qemu-aarch64-virt DEMO=baremetal run

Right now I'm using aarch64-none-elf-gcc (Arm GNU Toolchain 14.3.Rel1)

Can I ask what setup you're using?

[DavidMCerdeira]

My setup is based on the bao-demos, and I'm using Arm GNU Toolchain 14.2.Rel1 (Build arm-14.52) which is the toolchain version we recommend using in the bao-demos repo

If you can rebase this with main I believe I can run the CI build tests on this PR

[giacomogroppi]

There you go. Sorry to keep you waiting.

[DavidMCerdeira]

Greetings @giacomogroppi!

Thank you for the update, but the build is still failing and unfortunately we don't have the bandwidth to dig into this right now.
We'd welcome a fix from your side if you manage to track it down. Happy to review whenever you're ready.

[giacomogroppi]

Hi, I think I've managed to fix the build. I'm not too keen on having to pass a pointer to the macro just to check whether the operation was successful or not, so if you have any other ideas, let me know.

[DavidMCerdeira]

Looks like the builds are fixed! Great!

I'm not too keen on having to pass a pointer to the macro just to check whether the operation was successful or not, so if you have any other ideas, let me know.

Instead of macros it's better to use static inline functions, this way we can easily check the return value.

[giacomogroppi]

ok, i'll update the code in the next days, thank you

[giacomogroppi]

Hi! I've made the changes we discussed by converting some macros into static functions. I look forward to hearing back from you.