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From: Alan <alan@lxorguk.ukuu.org.uk>
To: <pledr@t-online.de>
Cc: <linux-kernel@vger.kernel.org>
Subject: Re: mapping of pages out of upper 128MB into kernel address space
Date: Wed, 22 Nov 2006 18:29:14 +0000	[thread overview]
Message-ID: <20061122182914.360752ef@localhost.localdomain> (raw)
In-Reply-To: <1GmwSV-2BnPRg0@fwd32.sul.t-online.de>

On 22 Nov 2006 18:05 GMT
<pledr@t-online.de> wrote:

> Hi,
> in a kernel module I have to translate user addresses into kernel addresses. The user uses shared memory allocated with shm_open / ftruncate. This shared memory is allocated somewhere in the upmost 128MB of physical memory that is NOT permanently mapped into the kernel ( found in swapper_pg_dir ). How can I "smp_save" map this memory into the kernel address space ?

See how copy_highpage and friends are used by copy_to/from_user. The
kmaps are a limited resource so you can only really use them to briefly
map objects in this way.

Alan

      reply	other threads:[~2006-11-22 18:23 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-11-22 18:05 mapping of pages out of upper 128MB into kernel address space pledr
2006-11-22 18:29 ` Alan [this message]

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