Re: Address space question

• To: <oskit-users@fast.cs.utah.edu>
• Subject: Re: Address space question
• From: Gopalakrishnan Suresh <gsuresh@research.bell-labs.com>
• Date: Mon, 8 Jul 2002 10:56:15 -0400 (EDT)
• In-Reply-To: <Pine.GSO.4.43L-024.0207032227400.18285-100000@unix3.andrew.cmu.edu>
• Sender: owner-oskit-users@fast.cs.utah.edu

On Wed, 3 Jul 2002, Stephen A Muckle wrote:
> Anyhow, the problem I get sometimes is that when my scheduler goes and
> lets a process continue running that was once interrupted, somehow the
> DS and ES segment selectors are set to 0, even though I set them to
> segments that span the entire address space at DPL 3 right before I
> switch to the user process. Since my user processes do use data, they
> promptly segfault (general protection fault).

How do you accomplish the switch? The switching code in
uvm/sproc/x86/sproc_switch.c seems to take special care to explicitly set
the DS and ES when using the lret (with an artificial stack frame) to
achieve the switch. And it seems to work.

--suresh

• Re: Address space question
• From: Stephen A Muckle <smuckle@andrew.cmu.edu>

• Re: Address space question
• From: Stephen A Muckle <smuckle@andrew.cmu.edu>

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