From: "H. Peter Anvin" <hpa@zytor.com>
To: matthieu castet <castet.matthieu@free.fr>
Cc: lkml <linux-kernel@vger.kernel.org>,
"linux-security-module@vger.kernel.org"
<linux-security-module@vger.kernel.org>,
Ingo Molnar <mingo@elte.hu>, Lin Ming <ming.m.lin@intel.com>,
Andi Kleen <andi@firstfloor.org>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH] x86 : Add NX protection for kernel data on 64 bit
Date: Mon, 14 Mar 2011 16:04:44 -0700 [thread overview]
Message-ID: <4D7E9F0C.2010504@zytor.com> (raw)
In-Reply-To: <4D7D0ED6.2050504@free.fr>
On 03/13/2011 11:37 AM, matthieu castet wrote:
> Cpu hotplug code read data in head_64.S (phys_base) before enabling NX, so when
> we enable NX on data, an triple fault happen because a reserved bit is set.
> It was fixed by allocating dedicated page table for ident mapping in trampoline.
> Now data can be protected by NX.
>
> The Low kernel Mapping is also set to NX.
>
> Finaly we preserve large page mapping by applying nx in free_init_pages only
> when we switch to NX mode
The right way to do this is to have initial_page_table and keep it
around, just as we already do on 32 bits... yet another thing that can
be merged instead of coming up with a separate solution.
-hpa
prev parent reply other threads:[~2011-03-14 23:05 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-13 18:37 [PATCH] x86 : Add NX protection for kernel data on 64 bit matthieu castet
2011-03-14 23:04 ` H. Peter Anvin [this message]
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