[OE-core] ARC arch support: uClibc status ?

[Khem Raj]

On Fri, Jun 23, 2017 at 6:50 AM, Alexey Brodkin
<Alexey.Brodkin at synopsys.com> wrote:
> Hi Khem,
>
> On Fri, 2017-06-23 at 06:46 -0700, Khem Raj wrote:
>> On Fri, Jun 23, 2017 at 6:40 AM, Richard Purdie
>> <richard.purdie at linuxfoundation.org> wrote:
>> >
>> > Hi,
>> >
>> > On Fri, 2017-06-23 at 15:23 +0200, Mylene Josserand wrote:
>> > >
>> > > We are currently adding to Yocto project the Synopsys ARC CPU
>> > > architecture, which is only available with uClibc library.
>> > >
>> > > We currently have a layer which adds the support of this
>> > > architecture
>> > > and uClibc support as it is, now, removed from OE-core.
>> > >
>> > > Many configurations/fixes are needed in OpenEmbedded-core's recipes
>> > > to
>> > > build successfully with this C library (library's dependencies,
>> > > autotools configuration, etc).
>> > >
>> > > We wanted to send patches to fix them but it seems that all uClibc's
>> > > references are now removed from OE-core, even in recipes:
>> > >
>> > > https://urldefense.proofpoint.com/v2/url?u=https-3A__patchwork.openembedded.org_patch_140943_&d=DwIBaQ&c=DPL6_X_6JkXFx7AXWqB0tg&r=lqdeeSSEes0GFD
>> > > Dl656eViXO7breS55ytWkhpk5R81I&m=vXM6W0k4FOex1pzJnHfSDtrgw08G-uIiKgZJinDWFtI&s=wd0w1NqlVaNUjpgkDUqxfK2izS-a-XotxpeCqt3Mcro&e=
>> > > https://urldefense.proofpoint.com/v2/url?u=https-3A__patches.openembedded.org_patch_140906_&d=DwIBaQ&c=DPL6_X_6JkXFx7AXWqB0tg&r=lqdeeSSEes0GFDDl
>> > > 656eViXO7breS55ytWkhpk5R81I&m=vXM6W0k4FOex1pzJnHfSDtrgw08G-uIiKgZJinDWFtI&s=4Y1JNumo1mAFnPDzX2CaFZw9gfkSF2TJa_vIGO8A9yA&e=
>> > >
>> > > What is the status of it? Remove entirely uClibc from OE-core?
>> > > Could you give us advice on how to handle uClibc?  Should we create
>> > > a
>> > > "meta-uclibc" layer which adds support of it + bbappend for all the
>> > > OE-core's recipes that currently fail because of uClibc's
>> > > misconfiguration?
>> > >
>> > > I guess that there is no plan to add uClibc's configuration in OE-
>> > > core's
>> > > recipes (even without uClibc itself), right?
>> >
>> > We dropped uclibc from OE-Core around a year ago in favour of musl
>> > since it seems to work for all the use cases we've been aware of from
>> > our users and nobody was willing to maintain it.
>> >
>> > Since then the uclibc overrides and other pieces in core have bitrotted
>> > to the point it was clear nobody was actively using or maintaining
>> > them. I therefore proposed some patches removing them, those were
>> > agreed by several developers and no objections were seen. We therefore
>> > cleaned up the remaining pieces.
>> >
>> > I believe that we have enhanced the extension mechanisms within the
>> > core such that a meta-uclibc layer would be possible now, even for the
>> > site files and insane.bbclass mappings and so on. It would need to add
>> > some of the extensions removed from the core and then it should be
>> > buildable again.
>> >
>> > If you can't make anything work from the layer let us know and we can
>> > try and figure out a way to solve that. I don't think the uclibc pieces
>> > would be coming back into OE-Core any time soon though as whilst it
>> > does have some niche markets left (e.g. arc), I can't see it being
>> > widely used by the majority of OE users/arches.
>> >
>> > (As an aside I haven't looked at it at all but does musl support arc?)
>> >
>>
>> I dont see arc support in upstream musl, It could good if it was there
>> since that could unleash whole OE on arc architecture. We can do
>> successful world builds on musl much like glibc now a days.
>
> Indeed there's no musl port for ARC [yet].
> But we're almost done with glibc port and it looks like we'll need to switch
> to glibc for OE/Yocto which I believe is doable.
>
> I guess glibc is still the first class-citizen in OE, right?
>

yes that is right.

> -Alexey