Date: Thu, 16 Apr 1998 14:57:00 -0700 (PDT) From: Bernie Doehner <bad@uhf.wireless.net> To: Mike Smith <mike@smith.net.au> Cc: Bernie Doehner <bad@uhf.wireless.net>, Bernie Doehner <bad@ece.WPI.EDU>, hackers@FreeBSD.ORG, buaas@wireless.net Subject: Re: Documentation of 2.2.5-RELEASE and 3.0 memory protection? Message-ID: <Pine.BSF.3.96.980416145555.555A-100000@shf.wireless.net> In-Reply-To: <199804162122.OAA01195@dingo.cdrom.com>
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> > User-mode applications cannot access memory in the ISA hole without > using mmap() to obtain such a mapping, either agains /dev/mem or some > other device. One may alternatively open /dev/mem or /dev/kmem and > read/write to achieve the same result. Didn't know that.. Guess we need to look at the /dev/mem a little closer :) > A driver is a kernel component, linked into the kernel. A user-mode > program runs as a process with user priviledges. > > > But we'd like to understand the kernel mechanisms better so that we can > > move/some of it into the kernel and turn it into real device drivers. > > The ISA hole is mapped into the kernel's address space; drivers such as > if_ed's use of memory in this range are good examples of how to locate > and work with this mapping. See also how syscons accesses the video > framebuffer. > Thanks.. Bernie To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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