[ECOS] i386 memory questions

[David Brennan <ecos at brennanhome dot com>]

Hello,
Is there an easy way within the current eCos infrastructure to
disallow certain memory access? I recently completed a project using a
different real-time operating system that had a guard page set up for
page 0. Then any null pointer dereferencing caused a page fault. This
turned out to be incredibly useful (especially since the page fault
trapped to the debugger).

As far as I can read the start up files, eCos does not use the MMU
(which is the way the other OS implemented this). Can the GDT be
configured to do this same thing? If so, does that break the 1:1
correlation between physical address and logical address?

If this is not possible with the GDT, would it be "easy" to set up the
MMU on an i386 platform? I really don't know anything about that level
of hardware/software configuration. Is there a recommended
architecture to use as a model for implementing it in proper eCos
style?

I am not looking to set up various protection levels. I would just
like to catch programming mistakes.

Thank you
David Brennan

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