From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <490869D4.8040506@domain.hid> Date: Wed, 29 Oct 2008 14:49:08 +0100 From: Gilles Chanteperdrix MIME-Version: 1.0 References: <49083C20.6060306@domain.hid> In-Reply-To: <49083C20.6060306@domain.hid> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-core] rtdm_mmap_to_user() remapping problem on powerpc arch. List-Id: "Xenomai life and development \(bug reports, patches, discussions\)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Matteo Facchinetti @ Sirius Electronic Systems S.R.L." Cc: xenomai@xenomai.org 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.