linux-kernel - Re: Really good idea to allow mmap(0, FIXED)?

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Message-Id: <200610061644.33267.mb@bu3sch.de>
Date:	Fri, 6 Oct 2006 16:44:32 +0200
From:	Michael Buesch <mb@...sch.de>
To:	Alan Cox <alan@...rguk.ukuu.org.uk>
Cc:	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: Really good idea to allow mmap(0, FIXED)?

On Thursday 05 October 2006 23:58, Alan Cox wrote:
> Ar Iau, 2006-10-05 am 20:59 +0200, ysgrifennodd Michael Buesch:
> > Is is really a good idea to allow processes to remap something
> > to address 0?
> 
> It is very useful indeed. Consider for example dosemu.

Ok, good point.

> > Besides that, I currently don't see a valid reason to mmap address 0.
> > 
> > Comments?
> 
> User zero is not neccessarily mapped at kernel zero so your argument
> isn't portable either.

Eh, so what about the following.
We _have_ arches which map user zero to kernel zero. What about
specialcasing that on a per-arch case. So remapping user zero to
something else in kernel.

-- 
Greetings Michael.
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