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

["Liming Gao" <liming.gao@intel.com>]

Ard:

> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Ard Biesheuvel
> Sent: Friday, May 29, 2020 1:47 PM
> To: devel@edk2.groups.io; Gao, Liming <liming.gao@intel.com>; lersek@redhat.com; Leif Lindholm <leif@nuviainc.com>
> Cc: philmd@redhat.com; mliska@suse.cz
> Subject: Re: [edk2-devel] [PATCH] MdePkg/Include: AARCH64: disable outline atomics on GCC 10.2+
> 
> On 5/29/20 5:18 AM, Liming Gao via groups.io wrote:
> > Leif:
> >   I get the point that the linux distribution default GCC version may be 10 or above. Without this fix, those developers can’t pass
> build edk2-stable202005. So, you think this is a critical issue to catch stable tag 202005.
> >
> > Ard:
> >    For this patch, I have two minor comments.
> > 1) I suggest to remove Link: https://bugzilla.tianocore.org/show_bug.cgi?id=2723 from comments, because this information has
> been in the commit message.
> 
> I think it would be helpful to keep it but I won't insist.
> 

I agree this is useful. But, we record it in the commit message. I prefer to remove this link from source code.
With this change, Reviewed-by: Liming Gao <liming.gao@intel.com>

Thanks
Liming
> > 2) Can we think __GNUC_MINOR__ is always defined? Do we need to check its value after check whether it is defined or not?
> >
> 
> Yes __GNUC_MINOR__ is always defined.
> 
> 
> 
> > -----Original Message-----
> > From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Laszlo Ersek
> > Sent: 2020年5月29日 4:03
> > To: Leif Lindholm <leif@nuviainc.com>
> > Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>; devel@edk2.groups.io; Gao, Liming <liming.gao@intel.com>; philmd@redhat.com;
> mliska@suse.cz
> > Subject: Re: [edk2-devel] [PATCH] MdePkg/Include: AARCH64: disable outline atomics on GCC 10.2+
> >
> > On 05/28/20 12:05, Leif Lindholm wrote:
> >> 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.
> >
> > OK. That's a good argument. From my POV, feel free to merge (both patches).
> >
> > Thanks
> > Laszlo
> >
> >> 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
> >>>
> >>
> >
> >
> >
> >
> >
> >
> >
> 
> 
>