Re: Cross compiling user applications for armv7

On Sep 12, 2025, at 14:10, Michał Kruszewski <mkru@protonmail.com> wrote:

> A simple way is to set up an armv7 chroot / jail on an arm64 host such as a Raspberry Pi (Apple devices don't work!).
> Then it's just like a native environment, but usually much faster.

> I don't have physical arm64 host.
> I also don't want to create a VM.
> The whole idea seems weird and unnatural.

Ignoring the RPi4B detail:

FreeBSD official armv7 port-packages are built this way
on arm64 hardware that natively supports user-space
armv7 code. (ampere* systems are used.)

FreeBSD official i386 port-packages are built this way
on amd64 hardware that natively supports user-space
i386 code.

No use of qemu variants of any kind: no attempt at
non-native-capable host environments.

(Back when amd64 and qemu was used for the likes
of armv7, lots of stuff failed to build mcuh of
the time over the years --stuff that builds
just fine now. This was abandoned after native
became available. armv6 was always qemu based
on amd64 and could not build much as of the last
time a build was run.)

> It sounds more like an exotic workaround.

It is the official technique used for what FreeBSD
distributes for armv7 port-packages.

> Regards,
> Michał Kruszewski
> 
> 
> Sent with Proton Mail secure email.
> 
> On Friday, September 12th, 2025 at 10:46 PM, Robert Clausecker <fuz@fuz.su> wrote:
> 
>> Hi Michał,
>> 
>> A simple way is to set up an armv7 chroot / jail on an arm64 host such as
>> a Raspberry Pi (Apple devices don't work!). Then it's just like a native
>> environment, but usually much faster.
>> 
>> Yours,
>> Robert Clausecker
>> 
>> Am Fri, Sep 12, 2025 at 04:19:42PM +0000 schrieb Michał Kruszewski:
>> 
>>> Is there any tutorial on how to cross compile custom user application for armv7?
>>> I struggle t find any.
>>> Cross compiling the system is pretty easy.
>>> However, how can one cross compile custom user application or kernel drivers.
>>> 
>>> Regards,
>>> Michał Kruszewski
>>> 
>>> Sent with Proton Mail secure email.
>> 
>> 
>> --
>> () ascii ribbon campaign - for an encoding-agnostic world
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> 
> 
===
Mark Millard
marklmi at yahoo.com