Re: Question on BIGGEST_ALIGNMENT in GCC on NetBSD/m68k
On Mon, 2025-06-16 at 08:33 +0200, Laurent Vivier wrote:
>
> Le 14/06/2025 à 09:21, John Paul Adrian Glaubitz a écrit :
> > On Fri, 2025-06-13 at 17:24 +0200, Laurent Vivier wrote:
> > > A stupid question: is this possible to remove from debian the packets
> > > that are broken?
> > > (I'm sorry if you already answered to this question).
> >
> > Sure, we can remove Python on m68k. But whether it will still be useful
> > after that remains a different question. I would argue we should rather
> > totally drop the port then because Linux without Python doesn't really
> > work these days.
>
> You can see the fix for python has been merged 5 days ago...
And yet it's not just Python. The 2 bytes alignment is still the main blocker
for Rust on m68k. More and more important Python packages such as python-
cryptography are embedding Rust code these days. There is no way around it.
> > > Because I'm afraid that changing the ABI could cause more problems than
> > > it solves.
> >
> > For what exact reason? NetBSD/m68k runs with 4 bytes alignment.
> > Why shouldn't this work for Linux?
>
> The problem is not the 4 byte alignment but changing the ABI.
Gentoo does it as well. I haven't heard any criticism towards Gentoo, just
people unloading all their frustration on me.
> You will create the exact same problem you want to fix: we can guess
> some softwares are built on linux/m68k with 2byte alignment in mind. So
> once the ABI is changed, you'll have to track them to fix them.
Could you point me to these packages which assume 2 bytes alignment? I'm genuinely
interested as I would like to put these up on the wiki. So far I haven't found any.
I have used Debian's rebootstrap to create an initial set of m68k packages with
4 bytes alignment and didn't run into any problems yet.
The Gentoo developers have also successfully created a chroot with 4 bytes alignment:
https://dev.gentoo.org/~dilfridge/m68k/
I have tried it and it worked fine for me with qemu-user.
So, if there is any software that is incompatible with 4 bytes alignment on m68k, I
would like to hear about it.
> >
> > And I have bootstrapped Debian/m68k using rebootstrap with 4 bytes alignment
> > without any problems. If you think there are problems with 4 bytes alignment,
> > I would like to see them reported.
>
> Adrian, I respect all the work you do for debian ports and particularly
> on m68k, but I want to point out that this ABI change can generate more
> problems than it solves.
Then you should point me to these problems. So far, I have only heard vague warnings
but not concrete evidence that justifies your fear. In fact, I have provided more
evidence for the transition to work than any of the people in this discussion that
claim that it won't.
Adrian
--
.''`. John Paul Adrian Glaubitz
: :' : Debian Developer
`. `' Physicist
`- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913
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