Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!nrl-cmf!cmcl2!brl-adm!brl-smoke!gwyn
From: gwyn@brl-smoke.ARPA (Doug Gwyn )
Newsgroups: comp.unix.wizards
Subject: Re: Aliasing text and data segments of a process
Message-ID: <7209@brl-smoke.ARPA>
Date: 29 Jan 88 21:42:50 GMT
References: <202@sdti.UUCP> <730@umbc3.UMD.EDU> <7156@brl-smoke.ARPA> <452@minya.UUCP> <246@vcvax1.UUCP>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 8

In article <246@vcvax1.UUCP> naren@vcvax1.UUCP (naren) writes:
>	Now, if you REALLY want to do this, you could write a new system call 
>like mktext(vaddr, length)...

In case it isn't obvious to everyone, the reason why this can be done is that
the operating system kernel has special privileges and can therefore shuffle
around virtual->physical address mappings and associated attributes, but an
ordinary user-mode process cannot do this itself.  That's why IPC via shared
memory requires kernel support, for example.