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From: Lawrence D'Oliveiro <ldo@nz.invalid>
Newsgroups: comp.arch
Subject: Re: Privilege Levels Below User
Date: Tue, 11 Jun 2024 04:18:26 -0000 (UTC)
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On Mon, 10 Jun 2024 17:11:47 -0600, John Savard wrote:

> Write can be enabled to memory. Only enabling write and execute together
> is potentially subject to restricions.

I was going to say, it might be acceptable in current programming 
environments to keep the two states (writable versus executable) carefully 
separated, with an explicit transition from one to the other.

But it turns out this isn’t always enough. I wrote some C code taking 
advantage of the GCC extension that lets you define nested routines, and 
in that situation it creates “thunks” to allow inner routines to access 
local variables in outer routines, and that requires an executable stack.