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

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

Ard: 
  Lefi requests to catch this change into 202005 stable tag. I also highlight this request in hard feature freeze notice mail https://edk2.groups.io/g/devel/message/60421.

  If no objection before the middle of next week (2020-06-03), this patch can be merged with the updated comments.

Thanks
Liming
> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Ard Biesheuvel
> Sent: Saturday, May 30, 2020 12:51 AM
> To: Gao, Liming <liming.gao@intel.com>; devel@edk2.groups.io; lersek@redhat.com; Leif Lindholm <leif@nuviainc.com>
> Cc: philmd@redhat.com; mliska@suse.cz; Kinney, Michael D <michael.d.kinney@intel.com>; afish@apple.com
> Subject: Re: [edk2-devel] [PATCH] MdePkg/Include: AARCH64: disable outline atomics on GCC 10.2+
> 
> On 5/29/20 4:29 PM, Gao, Liming wrote:
> > 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>
> >
> 
> 
> Works for me.
> 
> I will send a v2 after the stable tag is released.
> 
> 
> >>> 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
> >>>>>
> >>>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>
> >>
> >>
> >
> 
> 
>