Re: armv6 support for rust?

[Brad Spencer <brad%anduin.eldar.org@localhost>]

Havard Eidnes <he%NetBSD.org@localhost> writes:

>> Right now we only build rust for armv7, but the RPI Zero and
>> other cheapo Rapsberry Pi boards are v6. Since rust is becoming
>> even more of a critical dependency (compare py-cryptography),
>> it would be really nice to get rust for armv6.
>>
>> It can't be the only 32-bit arm port (like how we downgraded
>> the 32-bit x86 one to i586 to support embedded boards), because
>> backwards compatibility is less of a priority for the arm folks and
>> newer hardware is missing deprecated instructions.
>>
>> It looks like there is already support upstream, so it just
>> falls on there being existing bootstrap tarballs, hopefully? :)
>
> I'll take a look at this, it may be as easy as it was when I
> enabled the aarch4_be port earlier.
>
> Related to this, I might need an armv6 VM to check if "native"
> binaries can be built.  I currently run my armv7hf VM via
>
> #!/bin/sh
> SMP=4
> MEM=4g
> #  -kernel netbsd-GENERIC.ub -append root=ld4a
> qemu-system-arm -M virt -smp $SMP -m $MEM \
>   -drive if=none,file=disk.img,id=hd0 -device virtio-blk-device,drive=hd0 \
>   -netdev type=user,id=net0,hostfwd=tcp::2222-:22,ipv6=off \
>   -nographic \
>   -device virtio-net-device,netdev=net0,mac=00:11:66:33:44:55 \
>   -bios QEMU_EFI.fd
>
> Any idea what I need to change to force this to be an armv6 host?
> This may be a question of which "-cpu <value>" to use, and I'm
> sufficiently un-familiar with the arm jungle to be able to
> immediately realize which one of the various cortex variants to
> use, for instance.
>
> And which boot image should I start from?
>
> Regards,
>
> - Havard


I think that maybe the larger problem might be the image / kernel.  Can
a GENERIC armv6 kernel that uses UEFI exist?  I don't think that if you
build the system with build.sh for earmv6hf that you will end up with
one.

(I tried to find this some time ago as I wanted to do the same thing,
but the closest thing was the ability of qemu to boot a RPI kernel
directly if you were Linux)



-- 
Brad Spencer - brad%anduin.eldar.org@localhost - KC8VKS - http://anduin.eldar.org