Message-ID: <4048CC7F.4070009@techsource.com>
Date: Fri, 05 Mar 2004 13:52:47 -0500
From: Timothy Miller <miller@techsource.com>
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To: root@chaos.analogic.com
CC: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: kernel 'simulator' and wave-form analysis tool?
References: <4048B36E.8000605@techsource.com> <Pine.LNX.4.53.0403051253220.32349@chaos>
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Richard B. Johnson wrote:

> 
> 
> If you are making hardware that goes between the CPU and the
> rest of the world, then you can keep track of anything that's
> going on with some hardware-software combination, external
> to the chip you are analyzing. These things exist and they
> are called emulators, even though most don't emulate anything,
> they use the real chip, but provide the physical and logical
> connections to the user. However, in the case of an already-made
> machine, you are limited in what you can do on the machine
> with software. For instance, to trap every memory access, you
> would need a trap-handler and set all the memory to trap
> on an access. This would a bit hard to do within the kernel
> because all the code on that page would trap as instructions
> were fetched. So, some mere "hook" won't do it, you need
> a kernel that executes a kernel and I think one for Linux
> already exists. So, before you get too involved, you might
> want to check that out.


I must have been unclear.  I was not suggesting adding hardware.  I was 
suggesting that we could run Linux under Bochs, which is a software x86 
emulator.  Being what it is, hooks can be added to track "cpu activity" 
is it occurs within the emulator.  This is all a simulation.  The key 
idea I was suggesting was to log processor activity (of the emulator) 
and develop a viewer program which would help people visualize the activity.

Bochs already has hooks.  I could write a logger and a viewer.

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