From: Zoltan Menyhart <Zoltan.Menyhart_AT_bull.net@nospam.org>
To: linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC] prevent "dd if=/dev/mem" crash
Date: Thu, 23 Oct 2003 11:31:53 +0200 [thread overview]
Message-ID: <3F97A009.1C12F466@nospam.org> (raw)
In-Reply-To: <20031023083316.GB5272@sourcefrog.net>
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
next prev parent reply other threads:[~2003-10-23 9:31 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-10-17 22:10 Bjorn Helgaas
2003-10-17 22:23 ` Matt Mackall
2003-10-17 22:50 ` Andrew Morton
2003-10-17 23:25 ` Bjorn Helgaas
2003-10-17 23:55 ` Andrew Morton
2003-10-18 0:15 ` William Lee Irwin III
2003-10-18 0:21 ` David Mosberger
2003-10-18 0:49 ` Andrew Morton
2003-10-18 1:31 ` Matt Chapman
2003-10-18 1:41 ` Andrew Morton
2003-10-18 1:48 ` David Mosberger
2003-10-18 2:01 ` Andrew Morton
2003-10-18 2:01 ` Matt Chapman
2003-10-19 11:25 ` Eric W. Biederman
2003-10-19 19:01 ` William Lee Irwin III
2003-10-20 15:17 ` Bjorn Helgaas
2003-10-20 18:48 ` David Mosberger
2003-10-20 15:58 ` fielding PCI bus timeouts - was: " Rich Altmaier
2003-10-20 17:42 ` [RFC] " Bjorn Helgaas
2003-10-23 21:05 ` Bjorn Helgaas
2003-10-19 18:17 ` Pavel Machek
2003-10-23 8:33 ` Martin Pool
2003-10-23 9:31 ` Zoltan Menyhart [this message]
2003-10-17 22:19 Luck, Tony
2003-10-17 22:40 ` Andreas Schwab
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