linux-kernel - Re: -tip tree resume fail, bisect to 5bd5a45(x86: Add NX protection for kernel data)

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Message-ID: <20101122092003.GA21836@basil.fritz.box>
Date:	Mon, 22 Nov 2010 10:20:03 +0100
From:	Andi Kleen <andi@...stfloor.org>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Lin Ming <ming.m.lin@...el.com>,
	Matthieu Castet <castet.matthieu@...e.fr>,
	Siarhei Liakh <sliakh.lkml@...il.com>,
	Xuxian Jiang <jiang@...ncsu.edu>,
	Arjan van de Ven <arjan@...radead.org>,
	Andi Kleen <andi@...stfloor.org>,
	lkml <linux-kernel@...r.kernel.org>
Subject: Re: -tip tree resume fail, bisect to 5bd5a45(x86: Add NX
 protection for kernel data)

On Mon, Nov 22, 2010 at 09:07:10AM +0100, Ingo Molnar wrote:
> > ---[ High Kernel Mapping ]---
> > ....
> > 0xffffffff81a00000-0xffffffff81c00000           2M     ro         PSE GLB NX pmd
> > 0xffffffff81c00000-0xffffffff81d91000        1604K     ro             GLB NX pte
> > 0xffffffff81d91000-0xffffffff81e00000         444K     ro             GLB NX pte
> > 0xffffffff81e00000-0xffffffff82000000           2M     RW         PSE GLB NX pmd
> > 0xffffffff82000000-0xffffffff8200c000          48K     RW             GLB NX pte
> > 0xffffffff8200c000-0xffffffff82100000         976K     RW             GLB NX pte
> > 0xffffffff82100000-0xffffffff82200000           1M     RW             GLB NX pte
> > .....
> > 
> > The only difference is 0xffffffff81e00000(end) to 0xffffffff82200000(kernel_end) is set to NX.
> > 
> > I guess this range code is used by resume wakeup code. So setting it to NX causes problem.
> > 
> > Any idea?
> 
> Yeah, the resume area is a trampoline, it needs to be executable.

Also it looks like most of the kernel linker supplied data is now not 
2MB mapped anymore? That will surely cost TLB entries.

-Andi

-- 
ak@...ux.intel.com -- Speaking for myself only.
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