Re: [RFC] prevent "dd if=/dev/mem" crash

From: Zoltan Menyhart <Zoltan.Menyhart_AT_bull.net_at_nospam.org>
Date: 2003-10-23 19:31:53
Some machines may require special memory zones, e.g. for ia64
architectures you need to keep the "minimal state save" area
for the Processor Abstraction Layer in un-cached memory.
If you read the memory "in the usual way" then you access the
memory through the HW caches.
The ia64 architecture forbids to have both cached and un-cached
access to the same memory location (by any of the CPUs, DMAs),
otherwise you create a cache paradox => machine check.
Think twice before even trying a "dd if=/dev/mem"...

Zoltan Menyhart
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Received on Thu Oct 23 05:34:45 2003

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