Date: Fri, 15 Sep 2006 23:21:34 +0800 From: LI Xin <delphij@delphij.net> To: John Baldwin <jhb@freebsd.org> Cc: freebsd-arch@freebsd.org Subject: Re: How to map a page with userland program? Message-ID: <450AC4FE.6070303@delphij.net> In-Reply-To: <200609151035.12069.jhb@freebsd.org> References: <450AB80B.1050100@delphij.net> <200609151035.12069.jhb@freebsd.org>
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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. That would make it easier to implement some sort of VSYSCALL, which is in fact executed in userland. Or, is there any better way? :-) Cheers, -- Xin LI <delphij@delphij.net> http://www.delphij.net/ FreeBSD - The Power to Serve!
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