From: Matthew Garrett <mjg59@srcf.ucam.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org, matt.fleming@intel.com
Subject: Re: [PATCH] EFI: Only set regions uncacheable if they support it
Date: Thu, 15 Mar 2012 14:07:08 +0000 [thread overview]
Message-ID: <20120315140708.GA3395@srcf.ucam.org> (raw)
In-Reply-To: <4F61F5E6.8060509@zytor.com>
On Thu, Mar 15, 2012 at 07:00:06AM -0700, H. Peter Anvin wrote:
> On 03/15/2012 06:56 AM, Matthew Garrett wrote:
> > The EFI memory region attributes field indicates whether the region can
> > be mapped with various cache attributes. Our current implementation always
> > marks regions uncacheable if they don't have the writeback support flag.
> > This causes us to mark some regions uncacheable even if they don't
> > indicate support for being uncacheable, triggering a clflush that may cause
> > an MCE. Ensure we only do this for regions which support it.
> >
> > Signed-off-by: Matthew Garrett <mjg@redhat.com>
>
> Could you be specific as to what you're seeing in the field? In
> particular, what *do* these memory regions claim to support?
I have a report of a system that fails to boot with an MCE during EFI
setup. The memory range is marked reserved and claims not to support any
caching type, which I think probably translates as "Don't do anything to
this region ever".
--
Matthew Garrett | mjg59@srcf.ucam.org
next prev parent reply other threads:[~2012-03-15 14:07 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-15 13:56 [PATCH] EFI: Only set regions uncacheable if they support it Matthew Garrett
2012-03-15 14:00 ` H. Peter Anvin
2012-03-15 14:07 ` Matthew Garrett [this message]
2012-03-15 14:17 ` H. Peter Anvin
2012-03-15 14:24 ` Matthew Garrett
2012-03-15 14:28 ` H. Peter Anvin
2012-03-15 14:33 ` Matthew Garrett
2012-03-15 14:36 ` H. Peter Anvin
2012-03-15 14:42 ` Matthew Garrett
2012-03-15 14:47 ` H. Peter Anvin
2012-03-15 14:54 ` Matthew Garrett
2012-03-15 14:51 ` Alan Cox
2012-03-15 14:54 ` Alan Cox
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