Re: libmlx5 doesn't build on s390x

[Jarod Wilson <jarod-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On 2017-03-23 12:10 PM, Jason Gunthorpe wrote:
> On Thu, Mar 23, 2017 at 08:51:21AM -0400, Jarod Wilson wrote:
>> Not sure if it's intentional, but in my adventure of the past day or two to
>> get rdma-core v13 building across all the arches I need to build it for, I
>> discovered that the mlx5 bits silently don't build on s390x. No build
>> failure, they just aren't attempted, so far as I can see. The only sign of
>> failure was when rpm %files globs failed to locate mlx5 bits.
>
> I don't expect anything except mlx4 to *work* on s390 - fixing that
> would require making a common IOMEM accessor system.
>
> However, AFAIK, they should build..

See reply to Yishai. Not much is actually building on s390x. (Note: I'm 
not building for s390 sans-x at all).

>> I noted that mlx4 has some s390x-specific trickery in providers/mlx4/mmio.h,
>> and wondered if something similar was required for mlx5, or if "does not
>> work on s390x and isn't expected to" is the norm. Currently, my builds are
>> excluding mlx5 support on s390x due to the current state.
>
> It would be nice if you could post logs for these various
> failures..

Yeah, I can do that.

> My guess is that none of the DMA providers were compiled for S390,
> which happens if the system cannot compile util/udma_barrier.h.
>
> Perhaps this test is wrong?
>
> #elif defined(__sparc__) || defined(__s390x__)
>
> Maybe it should be
>
> #elif defined(__sparc__) || defined(__s390x__) || defined(__s390__)
>
> ??

Not sure. From rpm's perspective, I'm trying arch s390x, but maybe gcc 
is actually calling it s390.

> Also, you should expect mlx5 not to be built on ARM32 and in other
> places where we do not support user DMA. Can you accommodate this in
> the rpm spec file? Debian has the same issue too... You can simulate
> this on x86-64 by patching util/udma_barrier.h to always fail to
> compile.

We don't target arm32 at all, only arm64 (aarch64 in rpm parlance). I 
believe an 'ExcludeArch: %{arm} s390' is currently in my local spec. (I 
have a few tweaks to push up here still).

-- 
Jarod Wilson
jarod-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org
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