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Date: Thu, 04 Nov 2004 16:23:14 -0700
From: Scott Long <scottl@freebsd.org>
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To: Willem Jan Withagen <wjw@withagen.nl>
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cc: "arch@freebsd.org" <arch@freebsd.org>
Subject: Re: Booting questions ....
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Willem Jan Withagen wrote:
> Scott Long wrote:
> 
>> The loader has a protected mode environment.  It is apparently not all
>> that hard to port memtest86 into it.  I'd highly recommend doing this
>> rather than trying to hack up the early pmap initialization.
> 
> 
> Is that so.... I was unable to find that. :( can you give me a pointer??

Sorry, I know of some private efforts, but not any public efforts.

> 
> And like I wrote in the previous discussion. The algorithms are not all 
> that difficult to write. It is getting easy access to the memory.
> If you look at memtest86, you'll that they have to get a lot of work 
> done to get to the actual job: memory testing.
> And that only for the x86 type processors, which are already served by 
> memtest86.
> 
> But reading your question, the answer would be:
>     too complex to get this figured out

Not too complex, just full of landmines.  I'm not sure that you can put
generic code into the VM system to do this without concerning yourself
about the per-arch pmap layout.  Also, how do you handle traps that are
generated by the memtest?  That's another per-arch thing that you have
to think about.

Scott