Date: Mon, 08 Nov 2004 21:27:31 +0100 From: Willem Jan Withagen <wjw@withagen.nl> To: John Baldwin <jhb@FreeBSD.org> Cc: freebsd-arch@FreeBSD.org Subject: Re: Booting questions .... Message-ID: <418FD6B3.4040600@withagen.nl> In-Reply-To: <200411081353.15394.jhb@FreeBSD.org> References: <418AB176.9030604@withagen.nl> <200411051400.34684.jhb@FreeBSD.org> <418BE3D2.2030205@withagen.nl> <200411081353.15394.jhb@FreeBSD.org>
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John Baldwin wrote: [All about getting a flat memoryspace] >>>>Next is then which ranges are valid to test, and then things really start >>>>to get complicated and arch dependant. Which is why I ended up in >>>>machdep.c right after the setting up of the memory ranges. >>> >>>Heh, the above memory mapping is also i386 specific. Alpha only has a >>>small bit of memory mapped in the loader, same with sparc64, etc. >> >>Ehhhh, again more reasons to put this in the kernel, or something that >>closely resembles a kernel. > > > Well, part of the problem there is that the early kernel code is all MD > anyway. I think your best bet really is to write your own mini-kernel that > the loader can load to do this, but it will require MD stubs for early > bootstrapping as well as some kind of API for mapping a page so you can test > it and then unmap it, which is required for x86 machines with > 4GB of RAM > for example. I would start simple, and forget about PAE, since I do not have a PAE machine... Simple 1386, and amd64-smp is all I got. Then I'd rather look at other architectures, then look at PAE. If ever I get this far. Can you give me some hints from the current modules/source-files on i386 I would at least need to get somewhere. Because that would be the way I'd go: See if I can rip enough from the regular kernel to be able to build the mini-kernel. And give the way mi_startup works that would be a very nice/simple way to keep loading modules until there is enough to get the work done. Did anybody write a routine that "dumps" the module list before mi_startup start to work on it??? Or would that be my first assignment :) I'll start by copying my own sys-tree so work does not get overwritten by daily cvsup. --WjW
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