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From: Ville-Pertti Keinonen <will+freebsd-current@will.iki.fi>
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To: Bruce M Simpson <bms@spc.org>
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cc: Tim Robbins <tjr@freebsd.org>
Subject: Re: Atomic operations on i386/amd64
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Bruce M Simpson wrote:

>Have a look at Linux. They ended up doing a runtime self-modifying kernel
>hack so they could ship generic kernels which used the appropriate locking
>instructions on each x86 family CPU.
>  
>
The idea of using self-modification to select locking modes (although 
for optional preemption, SMP and debugging rather than CPU model) is 
also described in a DEC Technical Journal article:

http://research.compaq.com/wrl/DECarchives/DTJ/DTJF03/DTJF03SC.TXT

I'm not sure whether the Linux implementation uses the same technique.