From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: Re: [patch/rfc] multiprotocol blkback drivers (32-on-64) Date: Tue, 19 Dec 2006 14:20:21 +0000 Message-ID: References: <4587E9D5.8090600@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4587E9D5.8090600@suse.de> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Gerd Hoffmann , Jan Beulich Cc: Xen devel list List-Id: xen-devel@lists.xenproject.org On 19/12/06 13:32, "Gerd Hoffmann" wrote: >> - unconditionally using #pragma pack(), __attribute__(()), and __i386__ or >> __x86_64__ in public Xen headers is, in my opinion, a no-go (these header >> should all be suitable for building e.g. Windows drivers, too - I know this >> isn't >> generally the case at present, but I don't think anything else can be the >> goal, >> and hence the situation shouldn't be made worse) > > Ideas for that one? Ok to create xen/include/public/compiler.h with > that kind of stuff in? I think it would be reasonable to put this stuff in a (new) Linux-specific header file that wraps the Xen-public blkif.h. We could put just enough support in blkif.h itself to allow it to be multiply-compiled. Then different OSes can wrap or rewrite blkif.h as they see fit to get the required layout for 32-bit and 64-bit ABIs. This conveniently sidesteps some of these issues and allows you to concentrate on Linux and GCC, while not constraining the implementation choices for anyone else. -- Keir