Re: ppc64el: IEEE 128-bit long double instead of IBM 128-bit long double
Hi Aurelien
f.y.i. I don't think your message made it to the debian-powerpc mailing list.
On Sat, 6 Sept 2025 at 15:33, Aurelien Jarno <aurel32@debian.org> wrote:
> It seems to be causing FTBFS due to packages that do not appear there,
> for instance util-linux also needs a rebuild to get systemd working. I
> am therefore not sure that this method of "let's see what fails and fix
> it" works, even with the help of autopkgtest. The risk is to find issue
> way later in the release cycle.
Thanks for reporting.
> It gets that by looking at the Tag_GNU_Power_ABI_FP in the elf headers. For instance:
>
> In forky:
>
> | $ readelf --arch-specific /usr/lib/powerpc64le-linux-gnu/libboost_math_c99.so.1.83.0
> | Attribute Section: gnu
> | File Attributes
> | Tag_GNU_Power_ABI_FP: hard float, 128-bit IBM long double
>
> In sid:
>
> | $ readelf --arch-specific /usr/lib/powerpc64le-linux-gnu/libboost_math_c99.so.1.83.0
> | Attribute Section: gnu
> | File Attributes
> | Tag_GNU_Power_ABI_FP: hard float, 128-bit IEEE long double
>
> From that it's possible to just identify the binary packages that needs
> to be rebuilt. You will find such a list attached.
This is useful information, thanks!
> That said, strangely a few packages that got uploaded didn't seem to be
> affected (for instance gmp, libzstd or xzutils), while I confirm the
> issue for others (for instance boost1.83, boost1.88, fontconfig,
> poppler). Maybe things have changed since the Ubuntu rebuild, or
> something else is different.
I don't know about gmp, libzstd or xz-utils in particular, but some of
the autopkgtest failures I saw were in Python packages.
> Rebuilding libraries should be prioritized first, as rebuilding a binary
> that links only with a 128-bit IBM long double will work, but will still
> be tagged as using 128-bit IBM long double... I am not sure what happens
> at runtime though.
I expect over the coming weeks we'll see many uploads, as fixes for
GCC 15 and CMake 4 as well as new versions are uploaded, now that we
are unfrozen. We will get many of these rebuilds on ppc64el "for
free".
We can review your list again after some time, and I think it would be
good to make sure it is clear well ahead of the forky release.
Regards
Graham
Reply to: