From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Eric Lacombe <goretux@gmail.com>
Cc: Arjan van de Ven <arjan@infradead.org>,
Ingo Molnar <mingo@elte.hu>,
linux-kernel@vger.kernel.org
Subject: Re: [x86] do_arch_prctl - bug?
Date: Wed, 19 Nov 2008 13:06:14 -0800 [thread overview]
Message-ID: <49247FC6.8080201@goop.org> (raw)
In-Reply-To: <200811191023.16358.goretux@gmail.com>
Eric Lacombe wrote:
> Ok, thanks, so I suppose now that only doing :
> asm volatile("movl %0,%%gs" :: "r" (0));
> could corrupt the address of the PDA that resides actually in the MSR_GS_BASE.
> And that's why load_gs_index is used as it contains "swapgs" before and after
> the "mov to gs".
>
> Is that correct?
>
Yes, loading a selector into a segment register will load the lower 32
bits of the base from the ldt/gdt into the msr and zero the rest.
J
next prev parent reply other threads:[~2008-11-19 21:06 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-18 17:35 [x86] do_arch_prctl - bug? Eric Lacombe
2008-11-18 23:44 ` Eric Lacombe
2008-11-19 1:07 ` Jeremy Fitzhardinge
2008-11-19 9:23 ` Eric Lacombe
2008-11-19 21:06 ` Jeremy Fitzhardinge [this message]
2008-11-19 23:35 ` [x86] do_arch_prctl Eric Lacombe
2008-11-20 0:07 ` Jeremy Fitzhardinge
2008-11-20 0:22 ` Eric Lacombe
2008-11-24 12:24 ` Eric Lacombe
2008-11-24 18:22 ` Jeremy Fitzhardinge
2008-11-24 19:28 ` Eric Lacombe
-- strict thread matches above, loose matches on Subject: below --
2008-11-18 14:33 [x86] do_arch_prctl - bug? Eric Lacombe
2008-11-18 14:45 ` Arjan van de Ven
[not found] ` <200811181820.04064.goretux@gmail.com>
2008-11-18 17:35 ` Eric Lacombe
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