From: Olof Johansson <olof@lixom.net>
To: Jon Mason <jdmason@us.ibm.com>
Cc: Olof Johansson <olof@lixom.net>, Pavel Machek <pavel@suse.cz>,
Muli Ben-Yehuda <mulix@mulix.org>, Andi Kleen <ak@suse.de>,
Muli Ben-Yehuda <MULI@il.ibm.com>,
Linux-Kernel <linux-kernel@vger.kernel.org>,
discuss@x86-64.org, Andrew Morton <akpm@osdl.org>
Subject: Re: [PATCH RFC 2/3] x86-64: Calgary IOMMU - Calgary specific bits
Date: Tue, 14 Mar 2006 21:18:13 -0600 [thread overview]
Message-ID: <20060315031813.GF5170@pb15.lixom.net> (raw)
In-Reply-To: <20060315012733.GE7699@us.ibm.com>
On Tue, Mar 14, 2006 at 07:27:33PM -0600, Jon Mason wrote:
> > We're killing structures like that one by one on PPC, I just haven't
> > gotten around to dealing with tce_entry yet.
> >
> > The way to do it is to use masking and shifting by hand.
>
> Really? I thought this was much more elegant than masking and
> bitshifting (and less prone to errors). Is there a particular reason to
> do it that way?
Me too, but what I've been told is that there's no guarantee for the
union/struct layouts being exactly like you (and the hardware) expects
them to be across toolchains, etc.
The endianness issues are also painful, in architecture-specific code it's
obviously not as big an issue as in generic drivers. Single-architecture
system drivers are a grey area in that aspect, but it's better to set
good examples then bad ones for the generic driver writers looking for
example code.
-Olof
next prev parent reply other threads:[~2006-03-15 3:24 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-14 8:24 [RFC PATCH 1/3] x86-64: Calgary IOMMU - introduce iommu_detected Muli Ben-Yehuda
2006-03-14 8:25 ` [PATCH RFC 2/3] x86-64: Calgary IOMMU - Calgary specific bits Muli Ben-Yehuda
2006-03-14 8:26 ` [RFC PATCH 3/3] x86-64: Calgary IOMMU - hook it in Muli Ben-Yehuda
2006-03-14 23:03 ` Pavel Machek
2006-03-14 23:22 ` Jon Mason
2006-03-14 23:26 ` Pavel Machek
2006-03-15 0:06 ` Jon Mason
2006-03-15 1:38 ` Muli Ben-Yehuda
2006-03-14 23:03 ` [PATCH RFC 2/3] x86-64: Calgary IOMMU - Calgary specific bits Pavel Machek
2006-03-15 0:55 ` Jon Mason
2006-03-15 0:56 ` Olof Johansson
2006-03-15 1:27 ` Jon Mason
2006-03-15 3:18 ` Olof Johansson [this message]
2006-03-15 1:52 ` Muli Ben-Yehuda
2006-03-14 15:01 ` [RFC PATCH 1/3] x86-64: Calgary IOMMU - introduce iommu_detected Andi Kleen
2006-03-14 15:07 ` Muli Ben-Yehuda
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