Date: Fri, 15 Sep 2006 10:43:27 -0600 From: John Giacomoni <John.Giacomoni@colorado.edu> To: freebsd-arch@freebsd.org Cc: LI Xin <delphij@delphij.net> Subject: Re: How to map a page with userland program? Message-ID: <E54DFDB2-3F43-4DE0-8073-6F8E4EABC1C4@colorado.edu> In-Reply-To: <200609151035.12069.jhb@freebsd.org> References: <450AB80B.1050100@delphij.net> <200609151035.12069.jhb@freebsd.org>
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--Apple-Mail-3--357219016 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed On Sep 15, 2006, at 8:35 AM, John Baldwin wrote: > On Friday 15 September 2006 10:26, LI Xin wrote: >> Dear folks, >> >> Is there a continent and MI way to map a kernel page into userland >> address space under the same virtual address? It seems that this >> can be >> implemented through some routines in MD part of pmap, but is it >> possible >> to use higher level VM routines to do the job? > > Not to the same userland virtual address. Why do you need the same > virtual address anyway? If it's for pointers use offsets relative to > the start of the page instead. For what it is worth, I also have need of the same functionality. Specifically I'd like for the region's address space to be at the same offset for the kernel and multiple user-space applications. I'm passing messages around in shared memory and would prefer to eliminate the offset calculations for performance reasons. John G -- John.Giacomoni@colorado.edu University of Colorado at Boulder Department of Computer Science Engineering Center, ECCR 1B50 430 UCB Boulder, CO 80303-0430 USA --Apple-Mail-3--357219016 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; format=flowed --Apple-Mail-3--357219016--
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