Re: [PATCH v2 00/14] ARM: deprecated platform removal

[Yoshifumi SHU <envzhu@gmail.com>]

Hi Arnd and all,

I would like to request that the core Arm Cortex-M support be retained, specifically for v8-M.

I'm heavily using Arm Cortex-M / NOMMU Linux for academic research.
In particular, I frequently run Linux on newer Arm v8-M (Cortex-M33/M55/M85) processors.
However, dropping CONFIG_CPU_V7M also removes support for these newer CPUs.
Because v8-M is highly compatible with the older v7-M (Cortex-M3/M4/M7), the v8-M support is tightly coupled with CONFIG_CPU_V7M, despite the name. 
The major differences are essentially CPU IDs and PMSAv8 MPU support.
So I need the majority of CONFIG_CPU_V7M to support Arm v8-M. 

Regarding platform support, I don't need Linux-side device drivers.
In my current setup, Linux runs in a virtualized environment hosted by an RTOS (like Zephyr) and accesses devices through virtio served by the RTOS.
I also understand that maintaining legacy MCU platform support is a significant burden.
Therefore, I don't object to removing the platform support, though the MPS platform remains convenient for bare-metal testing.

I am willing to help maintain this support, including modernizing the relevant code. I can regularly test kernels on real Armv8-M hardware.
If an active maintainer is required to keep the support, I am willing to take on that responsibility.
Please let me know how I can help keep the support.

Thanks,
Yoshifumi