Date: Mon, 20 Jul 2009 09:10:07 +0200
From: Sam Ravnborg <sam@ravnborg.org>
To: Siarhei Liakh <sliakh.lkml@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org,
       Andi Kleen <andi@firstfloor.org>, Rusty Russell <rusty@rustcorp.com.au>,
       Arjan van de Ven <arjan@infradead.org>, Ingo Molnar <mingo@elte.hu>,
       James Morris <jmorris@namei.org>,
       Andrew Morton <akpm@linux-foundation.org>, Andi Kleen <ak@muc.de>,
       Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>,
       linux-cris-kernel@axis.com, Roland Dreier <rdreier@cisco.com>
Subject: Re: [PATCH] x86: NX protection for kernel data
Message-ID: <20090720071007.GA6340@merkur.ravnborg.org>
References: <817ecb6f0907191243m33cc7369qa09a24416fad7769@mail.gmail.com> <20090719201330.GA3186@merkur.ravnborg.org> <817ecb6f0907191709u2abc756cm4bce635ee9b4d0d8@mail.gmail.com>
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> >
> > But here _edata does not cover until page boundary.
> > And alignmnet is located outside the output section
> > definition.
> > It would be better/more consistent to follow the style you use for .text here.
> 
> You are correct. _edata should be the last thing in .data, and
> alignment should be done before it. However, this brings up a
> question: was there any specific reason to leave .data.init_task
> beyond the _edata? Should we move _edata into the the last of the
> .data.* sections to have poper view of kernel layout?

.data.init_task is loaded into another segment so this is less trivial.
Jan Beulich has posted a patch some time ago to address this,
but it failed when forwardported to the unified layout.

Btw. -tip (the x86 tree) has a patch included that unify the definition
of _edata for 32 and 64 bit.
So the best thing you can do is to base your patch on top of
the -tip tree.

	Sam
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