From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailserv2.iuinc.com (qmailr@mailserv2.iuinc.com [206.245.164.55]) by puffin.external.hp.com (8.8.7/8.8.7) with SMTP id PAA27718 for ; Thu, 28 Oct 1999 15:02:47 -0600 Sender: frowand@cup.hp.com Message-ID: <3818B9F8.E38FFEA7@hp.com> Date: Thu, 28 Oct 1999 14:02:48 -0700 From: Frank Rowand Reply-To: frowand@cup.hp.com MIME-Version: 1.0 To: Paul Bame Cc: John David Anglin , Alan Cox , Helge.Deller@ruhr-uni-bochum.de, parisc-linux@thepuffingroup.com Subject: Re: [parisc-linux] hack to use HPUX boot loader References: <199910281838.MAA20701@debian.fc.hp.com> Content-Type: text/plain; charset=us-ascii List-ID: Paul Bame wrote: > > = > > = > > I find it very strange that the kernel is being linked to start at > = > > 0xc0010000. It's not your average machine that has this much physical > = > > = > Logical or physical ? > = > = Physical, at least when loading with hpux. LDFLAGS are "-R 0xc0010000 > = -N -e stext". I know at one time the link was being done at 0x10000. > > There isn't any concept of physical versus virtual > location in the HP linker that I'm aware of, though there might be somthing > hidden in an extension record. > > The hpux boot loader assumes the text relocation address should also be > used as a physical load address. In the case of Linux, relocated > at 3Gb, this clearly makes no sense. It works fine for HP-UX which > is relocated to, and runs in, low physical memory. > > = Does anyone know why this was changed? > > I assume the earlier linking was purely experimental, since I've been > told (and haven't confirmed myself) that Linux 2.2.x essentially needs > to be relocated at 3Gb (or some other big value) because it assumes > it's available from the page tables of every process. If > Linux was relocated at addresses near zero, this would result in > user programs having to start at addresses larger than the amount > of memory used by the kernel, which would be weird. > > -P Not so weird. It's just a virtual address, not a physical address. -Frank