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Date: Thu, 19 Dec 2002 14:16:02 -0800
From: "H. Peter Anvin" <hpa@transmeta.com>
Organization: Transmeta Corporation
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To: Jamie Lokier <lk@tantalophile.demon.co.uk>
CC: Linus Torvalds <torvalds@transmeta.com>, bart@etpmod.phys.tue.nl,
       davej@codemonkey.org.uk, terje.eggestad@scali.com, drepper@redhat.com,
       matti.aarnio@zmailer.org, hugh@veritas.com, mingo@elte.hu,
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Subject: Re: Intel P6 vs P7 system call performance
References: <20021219135517.7E78051FB6@gum12.etpnet.phys.tue.nl> <Pine.LNX.4.44.0212191134180.2731-100000@penguin.transmeta.com> <20021219221043.GA18562@bjl1.asuk.net>
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Jamie Lokier wrote:
> 
> Dynamic binaries or libraries can use the indirect call or relocate
> the calls at load time, or if they _really_ want a magic page at a
> position relative to the library, they can just _copy_ the magic page
> from 0xfffe0000.  It is not all that magic.
> 

That would make it impossible for the kernel to have kernel-controlled
data on that page|other page though...

I personally would like to see some better interface than mmap()
/proc/self/mem in order to alias pages, anyway.  We could use a
MAP_ALIAS flag in mmap() for this (where the fd would be ignored, but
the offset would matter.)

	-hpa


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