From: Andrew Morton <akpm@linux-foundation.org>
To: Jack Steiner <steiner@sgi.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org
Subject: Re: [PATCH] UV2 - Bug fix for GRU global addresses
Date: Thu, 8 Sep 2011 16:51:39 -0700 [thread overview]
Message-ID: <20110908165139.caa9ddef.akpm@linux-foundation.org> (raw)
In-Reply-To: <20110908182413.GA10782@sgi.com>
(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?
next prev parent reply other threads:[~2011-09-08 23:51 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-08 18:24 [PATCH] UV2 - Bug fix for GRU global addresses Jack Steiner
2011-09-08 23:51 ` Andrew Morton [this message]
2011-09-09 0:29 ` Jack Steiner
2011-09-09 0:50 ` Andrew Morton
2011-09-09 1:55 ` Jack Steiner
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