Re: [edk2-devel] [PATCH] MdePkg/Include: AARCH64: disable outline atomics on GCC 10.2+

["Leif Lindholm" <leif@nuviainc.com>]

On Wed, May 27, 2020 at 11:12:23 +0200, Laszlo Ersek wrote:
> >>> Oh and I think both this patch and the assembly language implementation
> >>> for the atomics should be delayed after the stable tag. gcc-10 is a new
> >>> toolchain; so even if we don't introduce a new toolchain tag such as
> >>> GCC10 for it, whatever we do in order to make it work, that's feature
> >>> enablement in my book.
> >>
> >> Works for me. By the time the next stable tag comes around, early adopters
> >> that are now on GCC 10.1 will likely have moved to 10.2 by that time, and so
> >> we may not need the assembly patch at all.
> > 
> > I'm not ecstatic that we'll be releasing the first stable tag known to
> > break with current toolchains.
> 
> If this breakage affects "current toolchains", then why was
> <https://bugzilla.tianocore.org/show_bug.cgi?id=2723> only reported on
> 2020-May-19, four days into the soft feature freeze?

I agree the timing is crap.

> > This isn't just affecting random crazies pulling latest toolchains
> > down, but people using their distro defaults (native or cross).
> 
> ... "people using their distro defaults" to *not* build upstream edk2
> until 2020-May-19, apparently.

Or distro defaults changing in between. I mean, we could say "Arch
is the same as any other distro's unstable", but I wouldn't want to go
down that route - I know people who use it for developing also for
qemu and linux.

Argh, I also just realised the error report I saw two days after
Ard's intrinsics patch hit the list was not a public report. Yes, if
this had affected only in-development/unstable distributions, I agree
this isn't something we should try to deal with upstream.

> > I don't recall if 10.1 ended up being default in F32, but it was
> > definitely included. In Arch, it does appear default.
> > 
> > Debian/Ubuntu are unaffected in their stable releases.
> > 
> > I agree it's a transitional issue, but I would really prefer to have
> > the intrinsics included in the release.
> 
> OK, let's delay the release then, by a few days. I agree the present
> patch may qualify as a bugfix, but the other patch with the assembly
> language intrinsics doesn't. If it's really that important to have in
> the upcoming stable tag, then it's worth delaying the tag for. I'm fine
> delaying the release for it; it wouldn't be without precedent.

I would argue it *is* a bugfix, since it only has an effect on builds
that would otherwise fail. But I also do think it is important enough
to delay the release if we feel that is necessary.

/
    Leif

> Also, I think Ard's assembly language patch needs a Tested-by from Gary
> at the least (reporter of TianoCore#2723). Please reach out to him in
> that thread.
> 
> ... More precisely, please *ping* Gary for a Tested-by in that thread,
> because Ard CC'd him from the start, and even credited Gary in the
> commit message.
> 
> Thanks,
> Laszlo
>