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Date: Mon, 12 Aug 2002 17:20:01 +0200 (CEST)
From: Ingo Molnar <mingo@elte.hu>
Reply-To: Ingo Molnar <mingo@elte.hu>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>,
       Linus Torvalds <torvalds@transmeta.com>, <linux-kernel@vger.kernel.org>,
       <julliard@winehq.com>, <ldb@ldb.ods.org>
Subject: Re: [patch] tls-2.5.31-C3
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On 12 Aug 2002, Alan Cox wrote:

> Which does mean you can steal the old TLS value and put it back across
> the calls just by changing the TLS data for that process. [...]

yes - the 0x40 segment can be saved & restored safely. We have per-CPU
GDTs so nobody can modify them while the APM BIOS is executing. (assuming
preemption is disabled.)

> [...] For that matter on Windows emulation I thought Windows also needed
> 0x40 to be the same offset as the BIOS does so can't we leave it
> hardwired ?

another thing: do we want this with descriptor priviledge level 3? Because
the APM 0x40 GDT entry was a ring 0 descriptor, but that would not be
accessible to Wine or DOSEMU.

	Ingo

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