From: Arjan van de Ven <arjan@infradead.org>
To: Ravikiran G Thirumalai <kiran@scalex86.org>
Cc: Ingo Molnar <mingo@elte.hu>,
venkatesh.pallipadi@intel.com, linux-kernel@vger.kernel.org,
tim@scalemp.com, shai@scalex86.org
Subject: Re: [patch] x86: Fix /dev/mem mmap breakage when PAT is disabled
Date: Thu, 30 Oct 2008 13:21:03 -0700 [thread overview]
Message-ID: <20081030132103.2daff1e1@infradead.org> (raw)
In-Reply-To: <20081030020203.GA12423@localdomain>
On Wed, 29 Oct 2008 19:02:03 -0700
Ravikiran G Thirumalai <kiran@scalex86.org> wrote:
> Fix mmap to /dev/mem when CONFIG_X86_PAT is off and
> CONFIG_STRICT_DEVMEM is off
>
> mmap to /dev/mem on kernel memory has been failing since the
> introduction of PAT (CONFIG_STRICT_DEVMEM=n case). Seems like
> the check to avoid cache aliasing with PAT is kicking in even
> when PAT is disabled. The bug seems to have crept in 2.6.26.
>
> This patch makes sure that mmap to regular kernel memory
> succeeds if CONFIG_STRICT_DEVMEM=n and
> PAT is disabled. The checks to avoid cache aliasing
> still happens if PAT is enabled.
well... technically the aliases are bad without PAT as well...
--
Arjan van de Ven Intel Open Source Technology Centre
For development, discussion and tips for power savings,
visit http://www.lesswatts.org
next prev parent reply other threads:[~2008-10-30 20:20 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-30 2:02 Ravikiran G Thirumalai
2008-10-30 18:29 ` Ingo Molnar
2008-10-30 20:59 ` Ravikiran G Thirumalai
2008-10-30 22:55 ` Ingo Molnar
2008-10-30 20:21 ` Arjan van de Ven [this message]
2008-10-30 21:21 ` Ravikiran G Thirumalai
2008-10-30 21:29 ` Arjan van de Ven
2008-10-30 21:54 ` Ravikiran G Thirumalai
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