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From: "H. Peter Anvin" <hpa@zytor.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>,
	linux-kernel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [git pull] x86 PAT changes
Date: Fri, 25 Apr 2008 17:06:12 -0700	[thread overview]
Message-ID: <481271F4.7060401@zytor.com> (raw)
In-Reply-To: <alpine.LFD.1.10.0804251351511.2779@woody.linux-foundation.org>

Linus Torvalds wrote:
> 
> So why is PAT dependent on NONPROMISC_DEVMEM here?
> 
> It seems pointless and wrong. Somebody might want to have both the full 
> /dev/mem and PAT.
> 

The problem is that that can create cached/uncached aliases, which can 
cause some processors to lock up (especially AMD is known to have a lot 
of errata in this area.)

	-hpa

  reply	other threads:[~2008-04-26  0:06 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-04-24 22:56 [git pull] x86 PAT changes Ingo Molnar
2008-04-25 23:43 ` Linus Torvalds
2008-04-26  0:06   ` H. Peter Anvin [this message]
2008-04-26  1:12     ` Linus Torvalds
2008-04-26  8:56       ` Ingo Molnar
2008-04-26 16:54         ` Pallipadi, Venkatesh
2008-04-26 17:15           ` Linus Torvalds
2008-04-26 18:32             ` Venki Pallipadi
2008-04-26 19:07               ` [patch] x86, PAT: disable /dev/mem mmap RAM with PAT Ingo Molnar
2008-04-26  9:57   ` [git pull] x86 PAT changes Ingo Molnar
2008-04-26 13:40 ` Gabriel C
2008-04-26 14:42   ` Ingo Molnar
2008-04-26 15:37     ` Gabriel C
2008-04-26 15:41       ` Ingo Molnar
2008-04-26 16:43         ` Linus Torvalds

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