[TUHS] Harvard and Von Neumann Architectures and Unix

Ian Zimmerman itz at very.loosely.org
Tue Nov 28 03:35:15 AEST 2017


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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