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From:   Zhenzhong Duan <zhenzhong.duan@gmail.com>
Date:   Wed, 23 Dec 2020 10:31:34 +0800
Message-ID: <CAFH1YnNwqrK+kHbLKH684AwPWM0TfOxKC37TfJe5FYZ4_AXRvA@mail.gmail.com>
Subject: Re: [PATCH] csky: Fix a size determination in gpr_get()
To:     Al Viro <viro@zeniv.linux.org.uk>
Cc:     Guo Ren <guoren@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-csky@vger.kernel.org, Oleg Nesterov <oleg@redhat.com>
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On Wed, Sep 23, 2020 at 12:52 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> On Wed, Sep 23, 2020 at 10:37:31AM +0800, Guo Ren wrote:
>
> > > What's going on there?  The mapping is really weird - assuming
> > > you had v0..v31 in the first 32 elements of regs->vr[], you
> > > end up with
> > >
> > > v0 v1 v2 v3 v2 v3 v6 v7 v4 v5 v10 v11 v6 v7 v14 v15
> > > v8 v9 v18 v19 v10 v11 v22 v23 v12 v13 v26 v27 v14 v15 v30 v31
> > >
> > > in the beginning of the output.  Assuming it is the intended
> > > behaviour, it's probably worth some comments...
> > FPU & VDSP use the same regs. 32 FPU regs' width is 64b and 16 VDSP
> > regs' width is 128b.
> >
> > vr[0], vr[1] =3D fp[0] & vr[0] vr[1], vr[2], vr[3] =3D vdsp reg[0]
> > ...
> > vr[60], vr[61] =3D fp[15] & vr[60] vr[61], vr[62], vr[63] =3D vdsp reg[=
15]
> > vr[64], vr[65] =3D fp[16]
> > vr[66], vr[67] =3D fp[17]
> > ...
> > vr[94], vr[95] =3D fp[31]
> >
> > Yeah, this is confusing and I'll add a comment later.
>
> Umm...  It would help if you described these 3 layouts:
>         1) kernel-side with VDSP
>         2) userland (identical to (1)?)
>         3) kernel-side without VDSP
> Still confused...
>
> PS: my apologies re commit message - I left a note to myself when doing
> that series and then forgot about it ;-/
>
> Anyway, which tree should it go through?  In any case, that fix is
> Acked-by: Al Viro <viro@zeniv.linux.org.uk>
> and I can take it through vfs.git or you guys can pick in csky tree;
> up to you.

Hi Al, Guo

Seems this patch is still pending=EF=BC=8C could you help check it=EF=BC=9F=
Thanks

Zhenzhong