Re: [PATCH] UV2 - Bug fix for GRU global addresses

Jack Steiner
2011-09-09T00:29:20Z

On Thu, Sep 08, 2011 at 04:51:39PM -0700, Andrew Morton wrote:
> (cc x86 maintainers)
>
> On Thu, 8 Sep 2011 13:24:13 -0500
> Jack Steiner <steiner@sgi.com> wrote:
>
> > This patch is a workaround for a UV2 hub bug that affects the format
> > of system global addresses.
> >
> > The GRU API for UV2 was inadvertently broken by a hardware change. The
> > format of the physical address used for TLB dropins and for addresses used
> > with instructions running in unmapped mode has changed. This change was not
> > documented and became apparent only when diags failed running on system simulators.
> >
> > For UV1, TLB and GRU instruction physical addresses are identical to socket
> > physical addresses (although high NASID bits must be OR'ed into the
> > address).
> >
> > For UV2, socket physical addresses need to be converted. The NODE portion of
> > the physical address needs to be shifted so that the low bit is in bit 39 or
> > bit 40, depending on an MMR value.
> >
> > It is not yet clear if this bug will be fixed in a silicon respin. If it
> > is fixed, the hub revision will be incremented & the workaround disabled.
>
> It's unclear to me whether this patch should be merged into 3.1 and/or
> into 3.0.x and earlier?

3.1 is fine. I can push directly to the distros.

--- jack