Date: Fri, 18 Sep 1998 14:09:39 -0400 (EDT) From: Scott Smyth <smyth@bashful.realminfo.com> To: Mike Smith <mike@smith.net.au> Cc: freebsd-hackers <freebsd-hackers@FreeBSD.ORG> Subject: Re: memory allocation above "physical" memory Message-ID: <Pine.LNX.3.96.980918140813.606K-100000@bashful.realminfo.com> In-Reply-To: <199809181706.KAA00787@word.smith.net.au>
next in thread | previous in thread | raw e-mail | index | archive | help
On Fri, 18 Sep 1998, Mike Smith wrote: > > If the kernel is hacked to only know about 64 MB, is there > > functionality already in the BSD kernel so allocate the memory > > that may lie above what the kernel "knows" about. For instance, > > in linux, vremap builds new page tables and returns a virtual > > address you can use. So, I am looking for a function that > > retrieves memory the kernel does not know about necessarily and > > maps it to virtual addresses (whether or not it is contigous in > > physical memory -- it may be). > > > > The example: physical memory the kernel knows: 64 MB, but the > > real memory banks hold 96 MB. How can I access the top 32 MB? > > Does functionality exist for: > > 1) getting page tables; > > 2) mapping page tables to virtual addresses. > > In most cases this is already taken care of; there should be no systems > on which physical memory is not correctly sized if you are running a > recent release or 3.0-current. > You are right. This is a special case. I am going to try creating a device that d_mmap() the memory and treats it like device pages (i.e., not managed by the kernel). It is similar to a frame buffer. I was just wondering if there were any standard functions similar to linux. Thanks -- Scott Smyth, Senior Developer R&D (770) 446-1332 ssmyth@realminfo.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?Pine.LNX.3.96.980918140813.606K-100000>