From: Bob Montgomery <bob.montgomery@hp.com>
To: Yinghai Lu <yinghai@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"vojtech@suse.cz" <vojtech@suse.cz>,
Linus Torvalds <torvalds@linux-foundation.org>,
"chandru@in.ibm.com" <chandru@in.ibm.com>,
Joerg Roedel <joerg.roedel@amd.com>,
FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>,
Jesse Barnes <jbarnes@virtuousgeek.org>,
Pavel Machek <pavel@ucw.cz>
Subject: Re: [PATCH] disable CPU side GART accesses
Date: Thu, 16 Oct 2008 13:26:48 -0600 [thread overview]
Message-ID: <1224185208.2215.301.camel@amd.troyhebe> (raw)
In-Reply-To: <86802c440810161043k4c4bf6e6x4f5a70c54c53ca3b@mail.gmail.com>
On Thu, 2008-10-16 at 17:43 +0000, Yinghai Lu wrote:
> On Thu, Oct 16, 2008 at 10:00 AM, Bob Montgomery <bob.montgomery@hp.com> wrote:
> >
> > The problem occurs when the copy operation reads from the GART aperture
> > (iommu window) and wakes up the GART translation hardware. This patch
> > stops that by telling the GART to ignore addresses that come from the
> > CPU and to only translate addresses from the IO side.
>
> why kdump need to copy those area? those area is supposed to be
> reserved in e820 table by BIOS or first kernel.
>
> YH
The crashdump analysis tools do not need a copy of this area. But if a
user tool associated with the kdump operation manages to touch it
through /proc/vmcore or /dev/oldmem, it can crash the kdump kernel.
This seemed like a simple and logical way to prevent that danger.
Bob Montgomery
next prev parent reply other threads:[~2008-10-16 19:26 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-15 21:48 [PATCH] disable CPU side GART accesses Bob Montgomery
2008-10-15 23:40 ` Linus Torvalds
2008-10-16 19:17 ` Bob Montgomery
2008-10-15 23:48 ` Ingo Molnar
2008-10-16 0:22 ` Yinghai Lu
2008-10-16 17:00 ` Bob Montgomery
2008-10-16 17:43 ` Yinghai Lu
2008-10-16 19:26 ` Bob Montgomery [this message]
2008-10-27 22:42 ` Bob Montgomery
2008-10-27 23:06 ` Yinghai Lu
2008-10-29 20:52 ` Bob Montgomery
2008-10-29 21:24 ` Dave Airlie
2008-10-29 21:32 ` Dave Jones
2008-10-29 21:40 ` Dave Airlie
2008-11-03 23:36 ` Bob Montgomery
2008-11-03 23:55 ` Dave Airlie
2008-11-19 22:12 ` Bob Montgomery
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