Re: [OSSTEST PATCH] README.hardware-acquisition [and 1 more messages] [and 2 more messages] [and 2 more messages]

[Julien Grall <julien.grall@arm.com>]

Hi,

On 02/11/2018 15:05, Ian Jackson wrote:
> Stefano Stabellini writes ("Re: [OSSTEST PATCH] README.hardware-acquisition [and 1 more messages] [and 2 more messages]"):
>> Thank you for the detailed answer and the willingness to see osstest
>> changed in this respect.
> 
> Sure.  It's not fixed in stone, and a variety of approachs will fit
> into it I think.
> 
>> Let me premise that as much as I would like this to be done, I had a
>> look at my schedule, and, realistically, I can only volunteer very
>> little time on this. In regards to the two Xilinx boards, it looks like
>> we'll just have to wait for Debian.
> 
> OK.  That's perhaps less work overall at our end anyway.  Let me know
> if you think any aspect of this is getting stuck somehow; I have
> contacts in Debian which I could use to enquire or whatever.
> 
>> On Thu, 1 Nov 2018, Ian Jackson wrote:
>>> The prerequisite is obviously an appropriate cross-compiler.  Will the
>>> Debian cross-compilers do ?
>>
>> Probably it would work, but I don't know for sure. Most people use the
>> Linaro compiler and toolchain:
>>
>> https://releases.linaro.org/components/toolchain/binaries/latest-7/aarch64-linux-gnu/
>> https://releases.linaro.org/components/toolchain/gcc-linaro/latest-7/
> 
> I guess that's probably tolerable.  We'd have to think about whether
> we should snapshot them, or install them directly from upstream.  The
> latter is less coding effort in osstest (just add an apt source and
> run the install rune I guess) but it would imply tracking these in an
> uncontrolled way, so we would want to be confident that they are
> maintained to a high standard, since problems with the compiler would
> break everything for us.  Also I would ask: how reliable is their apt
> repository hosting ?  If it goes down, likewise, everything would
> break for us.

Linaro hosting is pretty reliable. But AFAIK, they don't have an apt repo for 
the toolchains. We would need to download a tarball and unpack it.

> 
>> Testing the Debian cross-compiler would be very easy.
> 
> Perhaps Julien has time to do that.

Arm64 cross-compiler in Debian should be suitable enough for building the 
kernel. If there are any issue with them, then a bug report should be filled.

[...]

> Wei Liu writes ("Re: [OSSTEST PATCH] README.hardware-acquisition [and 1 more messages] [and 2 more messages]"):
>> Debian's cross-compiler package conflicts with its native compiler,
> 
> Specifically it conflicts with the multilib style native compiler used
> for Xen.  This is a bug in Debian but it is intractable because of the
> approach of the Debiabn GCC maintainer, so we will have to live with
> it.
> 
> However, this is not a blocker because osstest could use a dedicated
> x86 setup for the ARM cross builds.  That's not ideal because it
> shares resources less well, but it's certainly workable.
> 
> But maybe we just want to build on ThunderX.  That leaves steps 4-6 of
> my plan, which almost any approach (other than fixing the kernels in
> Debian) require.

My preference is to avoid cross-compiling if we can. This would avoid to use x86 
resource for building kernel that could be re-used for testing Xen itself.

Cheers,

-- 
Julien Grall

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