Re: Future of armv7

Hi John,

On Friday, November 14th, 2025 at 12:09 PM, John Baldwin <jhb@FreeBSD.org> wrote:

> Two and a half years ago when we first began talking about deprecating
> 32-bit architectures in 15.0, we decided to keep armv7 for at least
> the stable/15 branch but did not commit to anything beyond that. Now
> that 15.0 is close to shipping and we are turning our development
> focus to 16.0, we should figure out what we want to say about armv7
> for 16.x in the 15.0 release notes so that users have suitable notice.
> 
> In particular, do we want to deprecate armv7 in 16.0 (similar to the
> state of 32-bit powerpc in 15.0), or do we want to keep it?
> 
> My initial suggestion is that we announce that we plan to deprecate it
> in 16.0. In that case, I would also suggest that we follow a similar
> process of keeping armv7 for most of the lifetime of 16.0 so that we
> can reneg if need be during the 16.0 cycle.
> 
> What do other folks think?
> 
> --
> John Baldwin

I've been thinking on this matter for the last few days. But after reading others' replies, especially Ruslan's, I'm leaning towards the removal of armv7.

Below is the reason why I thought we should maintain armv7.
- armv7 is still widely used in some industries. As others said, our survey might have failed to count those people. We don't know the what the silent majority says yet, and unlike powerpc64be, many believes that armv7 still has its place somewhere.
- Maintaining at least one 32-bit platform makes porting FreeBSD to new 32-bit platforms easier in future.

Following is why I decided to vote towards the removal.
- Usage of armv7 hardwares have been quickly dwindling in the past few years. Since I started studying in univeristy, the only armv7 I've seen is ARM Cortex-M for old stm32 courses. Even including Cortex-M, I don't see anyone around me who uses armv7 in their project or work. stable/15 will give 3 more years of support for armv7, and I expect that people will use armv7 dramatically less by then.
- Warner mentioned OOM issues. 32-bit architectures usually have maximum memory capacity of 4GB, and introducing another 32-bit architecture won't solve this problem (unless they come up with something like PAE, but why would anyone come up with PAE if there are 64-bit architectures?). Thus, claims like "maintain at least one 32-bit architecture for future 32-bit architecture" don't really make sense to me. Even if we assume there will be a revolutionary 32-bit platform that can replace all existing 64-bit platforms under special circumstances, how do we know when the day will come? People in this list have said that there might be a future 32-bit platform, but I haven't heard what the plan is if there is NO such architecture in future. How can we tell? When is the time to remove armv7 if we really don't see another 32-bit alternative for decades?
- Cost of maintaining, testing, and releasing FreeBSD on these platforms. As FreeBSD build system encompasses different architectures and operating systems should abstract different hardwares, armv6 might affect code other than its own architecture-specific code, such as jemalloc that Warner have mentioned.

ARM and its ecosystem have changed a lot in the last few years. They seem to put more effort on server and high-end platforms than maintaining existing armv7 ecosystem. I think the FreeBSD project should follow the trend. As Poul has mentioned, many users are waiting for RPi5 support, and some are leaving due to lack of support for new boards. Rather than spending resources on maintaining architectures that are effectively legacy, we should focus on porting OS to new hardware.

Most operating system groups have goals. I believe that they should serve legacy hardware as much as they can, but once those hardwares become bottleneck to the development and cannot help achieve what the team is aiming for, it's time for the developers to retire them. I feel the time for armv7 will come by the EOF of stable/15.