From mboxrd@z Thu Jan  1 00:00:00 1970
From: itz@very.loosely.org (Ian Zimmerman)
Date: Mon, 27 Nov 2017 09:35:15 -0800
Subject: [TUHS] Harvard and Von Neumann Architectures and Unix
In-Reply-To: <20171127161141.2C9E318C08F@mercury.lcs.mit.edu>
References: <20171127161141.2C9E318C08F@mercury.lcs.mit.edu>
Message-ID: <20171127173515.s5ctvrv7uwvmmee4@matica.foolinux.mooo.com>

On 2017-11-27 11:11, Noel Chiappa wrote:

> Programs which emit these little 'custom code fragments' (I prefer
> that term, since they aren't really 'self-modifying code' - which I
> define as 'a program which _changes_ _existing_ instructions) must
> have some way of having a chunk of memory into which they can write,
> but which can also be executed.

As the writable/executable bits are usually in the page table (on linear
paged architectures which currently dominate the field), I imagine the
answer is dual page mappings.

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