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

["Laszlo Ersek" <lersek@redhat.com>]

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
>>
>