From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
To: "Matteo Facchinetti @ Sirius Electronic Systems S.R.L."
<matteo.facchinetti@domain.hid>
Cc: xenomai@xenomai.org
Subject: Re: [Xenomai-core] rtdm_mmap_to_user() remapping problem on powerpc arch.
Date: Wed, 29 Oct 2008 14:49:08 +0100 [thread overview]
Message-ID: <490869D4.8040506@domain.hid> (raw)
In-Reply-To: <49083C20.6060306@domain.hid>
Matteo Facchinetti @ Sirius Electronic Systems S.R.L. wrote:
> Hi all,
>
> I'm using framework RTDM to develop my driver on embedded system mpc5200
> based.
> (kernel 2.6.24.4 (powerpc arch) - xenomai 2.4.3).
>
> I've need to use rtdm_mmap_to_user() to share a kmalloc() kernel memory
> in userspace.
> For this, I'm using the example in
> http://www.captain.at/xenomai-real-time-driver-example.php.
>
> Running a similar example I've discovered a problem in kmalloc remapping.
> The only way that I've found, to make remapping correctly, is to
> allocate an entire kernel mem page with __get_freepage() instead of
> kmalloc().
>
> I think that could be a bug in powerpc arch.
> what do you think about?
There are two known problems with memory mapping:
- one when using high memory (more than 1GB RAM), for which a proposed
fix is here:
https://mail.gna.org/public/xenomai-core/2008-09/msg00118.html
- one specifically on power pc, fixed here:
https://mail.gna.org/public/xenomai-help/2008-10/msg00096.html
--
Gilles.
prev parent reply other threads:[~2008-10-29 13:49 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-29 10:34 [Xenomai-core] rtdm_mmap_to_user() remapping problem on powerpc arch Matteo Facchinetti @ Sirius Electronic Systems S.R.L.
2008-10-29 13:49 ` Gilles Chanteperdrix [this message]
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