Date: Fri, 23 May 2003 09:25:25 +0300 From: Ruslan Ermilov <ru@FreeBSD.org> To: Peter Wemm <peter@wemm.org> Cc: Dag-Erling Smorgrav <des@ofug.org> Subject: Re: cvs commit: src/sys/amd64/amd64 genassym.c locore.S machdep.c mem.c nexus.c pmap.c trap.c vm_machdep.c src/sys/amd64/include bus_amd64.h param.h pmap.h vmparam.h src/sys/conf kern.mk Message-ID: <20030523062525.GF17107@sunbay.com> In-Reply-To: <20030523062145.A53A62A7EA@canning.wemm.org> References: <xzp8ysyxk5b.fsf@flood.ping.uio.no> <20030523062145.A53A62A7EA@canning.wemm.org>
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--xkXJwpr35CY/Lc3I Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, May 22, 2003 at 11:21:45PM -0700, Peter Wemm wrote: > Dag-Erling Smorgrav wrote: > > Peter Wemm <peter@FreeBSD.org> writes: > > > - The kernel is moved into the negative address space(!). > >=20 > > Read a lot of Knuth lately? :) >=20 > Heh, no. Its just a quirk of doing signed 32 and 48 bit addressing. Gcc > likes to generate 32 bit signed address relocations in the code generation > models that we use. This means it can reference symbols from -2GB through > 2GB. There are 48 virtual address bits (256TB) that are defined in this > version of the cpu spec, and it too is signed. So, it just seemed natural > to have the user own the positive half, and the kernel the negative half. > This probably isn't strictly necessary, we could allocate additional user > address space in the unused negative address space if 128TB isn't enough. > :-) >=20 amd64 isn't going to be positive, EvilKernel? ;) Cheers, --=20 Ruslan Ermilov Sysadmin and DBA, ru@sunbay.com Sunbay Software AG, ru@FreeBSD.org FreeBSD committer, +380.652.512.251 Simferopol, Ukraine http://www.FreeBSD.org The Power To Serve http://www.oracle.com Enabling The Information Age --xkXJwpr35CY/Lc3I Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (FreeBSD) iD8DBQE+zb7VUkv4P6juNwoRAvZcAJ4kS+w2dpFXEV2ODx8qdGoWdGn4owCfUdzL jQ2OyJ17s7cyl23NsIEmEK4= =J/OO -----END PGP SIGNATURE----- --xkXJwpr35CY/Lc3I--
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