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From: Dan Rosenberg <drosenberg@vsecurity.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Tony Luck <tony.luck@gmail.com>,
	linux-kernel@vger.kernel.org, davej@redhat.com,
	kees.cook@canonical.com, davem@davemloft.net, eranian@google.com,
	torvalds@linux-foundation.org, adobriyan@gmail.com,
	penberg@kernel.org, Arjan van de Ven <arjan@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Valdis.Kletnieks@vt.edu, Ingo Molnar <mingo@elte.hu>,
	pageexec@freemail.hu
Subject: Re: [RFC][PATCH] Randomize kernel base address on boot
Date: Tue, 24 May 2011 19:34:49 -0400	[thread overview]
Message-ID: <1306280089.1921.18.camel@dan> (raw)
In-Reply-To: <4DDC3A1A.6030006@zytor.com>

On Tue, 2011-05-24 at 16:07 -0700, H. Peter Anvin wrote:
> On 05/24/2011 04:04 PM, Dan Rosenberg wrote:
> > 
> >> 2. Not introduce a performance regression (we avoid locating in the
> >>    bottom 16 MiB for performance reasons, except on very small systems);
> > 
> > I altered the boot code so that it uses CONFIG_PHYSICAL_START, which
> > defaults to 16 MiB, as a lower bound on location.  So nothing will ever
> > get loaded below there, and I still can take advantage of higher
> > alignment granularity.  Are there other problems I'm not anticipating?
> > 
> 
> Please look at the discussion as to what led us to do things this way.
> 

Would you be able to point me to said discussion?  The only thing I can
find is this:

http://marc.info/?l=linux-kernel&m=124173552516435&w=2

This set PHYSICAL_START at 16 MB and alignment at 2/4 MB.  Then, three
days later, this was committed:

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=ceefccc93932b920a8ec6f35f596db05202a12fe

This sets the alignment to 16 MB, with the only justification being that
relocatable kernels also need to start above 16 MB.

Thanks,
Dan


  reply	other threads:[~2011-05-24 23:34 UTC|newest]

Thread overview: 95+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-24 20:31 [RFC][PATCH] Randomize kernel base address on boot Dan Rosenberg
2011-05-24 21:02 ` Ingo Molnar
2011-05-24 22:55   ` Dan Rosenberg
2011-05-24 21:16 ` Ingo Molnar
2011-05-24 23:00   ` Dan Rosenberg
2011-05-25 11:23     ` Ingo Molnar
2011-05-25 14:20       ` Dan Rosenberg
2011-05-25 14:29         ` Ingo Molnar
2011-05-24 23:06   ` H. Peter Anvin
2011-05-25 14:03     ` Dan Rosenberg
2011-05-25 14:14       ` Ingo Molnar
2011-05-25 15:48       ` H. Peter Anvin
2011-05-25 16:15         ` Dan Rosenberg
2011-05-25 16:24           ` H. Peter Anvin
2011-05-24 21:46 ` Brian Gerst
2011-05-24 23:01   ` Dan Rosenberg
2011-05-24 22:31 ` H. Peter Anvin
2011-05-24 23:04   ` Dan Rosenberg
2011-05-24 23:07     ` H. Peter Anvin
2011-05-24 23:34       ` Dan Rosenberg [this message]
2011-05-24 23:36         ` H. Peter Anvin
2011-05-24 23:14   ` H. Peter Anvin
2011-05-24 23:08 ` Dan Rosenberg
2011-05-25  2:05   ` Dan Rosenberg
2011-05-26 20:01 ` Vivek Goyal
2011-05-26 20:06   ` Dan Rosenberg
2011-05-26 20:16   ` Valdis.Kletnieks
2011-05-26 20:31     ` Vivek Goyal
2011-05-27  9:36       ` Ingo Molnar
2011-05-26 20:35 ` Vivek Goyal
2011-05-26 20:40   ` Vivek Goyal
2011-05-26 20:44     ` Dan Rosenberg
2011-05-26 20:55       ` Vivek Goyal
2011-05-27  9:38         ` Ingo Molnar
2011-05-27 13:07           ` Vivek Goyal
2011-05-27 13:38             ` Ingo Molnar
2011-05-27 13:13       ` Vivek Goyal
2011-05-27 13:21         ` Dan Rosenberg
2011-05-27 13:46           ` Ingo Molnar
2011-05-27 13:50           ` Vivek Goyal
2011-05-26 20:39 ` Dan Rosenberg
2011-05-27  7:15   ` Ingo Molnar
2011-05-31 16:52   ` Matthew Garrett
2011-05-31 18:40     ` H. Peter Anvin
2011-05-31 18:51       ` Matthew Garrett
2011-05-31 19:03         ` Dan Rosenberg
2011-05-31 19:07           ` H. Peter Anvin
2011-05-31 19:50           ` Ingo Molnar
2011-05-31 19:55           ` Ingo Molnar
2011-05-31 20:15             ` H. Peter Anvin
2011-05-31 20:27               ` Ingo Molnar
2011-05-31 20:30                 ` H. Peter Anvin
2011-06-01  6:18                   ` Ingo Molnar
2011-06-01 15:44                     ` H. Peter Anvin
2011-05-31 20:17             ` Dan Rosenberg
2011-05-26 22:18 ` Rafael J. Wysocki
2011-05-26 22:32   ` H. Peter Anvin
2011-05-27  0:26     ` Dan Rosenberg
2011-05-27 16:21       ` Rafael J. Wysocki
2011-05-27  2:45     ` Dave Jones
2011-05-27  9:40       ` Ingo Molnar
2011-05-27 16:11         ` Rafael J. Wysocki
2011-05-27 16:07     ` Rafael J. Wysocki
2011-05-27 15:42   ` Linus Torvalds
2011-05-27 16:11     ` Dan Rosenberg
2011-05-27 17:00     ` Ingo Molnar
2011-05-27 17:06       ` H. Peter Anvin
2011-05-27 17:10       ` Dan Rosenberg
2011-05-27 17:13         ` H. Peter Anvin
2011-05-27 17:16           ` Linus Torvalds
2011-05-27 17:38             ` Ingo Molnar
2011-05-27 17:20           ` Kees Cook
2011-05-27 17:16         ` Ingo Molnar
2011-05-27 17:21           ` Linus Torvalds
2011-05-27 17:46             ` Ingo Molnar
2011-05-27 17:53               ` H. Peter Anvin
2011-05-27 18:05                 ` Linus Torvalds
2011-05-27 19:15                   ` Vivek Goyal
2011-05-27 21:37                   ` H. Peter Anvin
2011-05-27 23:51                     ` H. Peter Anvin
2011-05-28 12:18                   ` Ingo Molnar
2011-05-29  1:13                     ` H. Peter Anvin
2011-05-29 12:47                       ` Ingo Molnar
2011-05-29 18:19                         ` H. Peter Anvin
2011-05-29 18:44                           ` Ingo Molnar
2011-05-29 18:52                             ` H. Peter Anvin
2011-05-29 19:56                               ` Ingo Molnar
2011-05-27 17:57               ` Linus Torvalds
2011-05-27 18:17                 ` Ingo Molnar
2011-05-27 18:43                   ` Kees Cook
2011-05-27 18:48                   ` david
2011-05-27 21:51                   ` Olivier Galibert
2011-05-27 22:11                     ` Valdis.Kletnieks
2011-05-28  0:50                     ` H. Peter Anvin
2011-05-28  6:32                     ` Ingo Molnar

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