From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (from majordomo@localhost) by oss.sgi.com (8.11.3/8.11.3) id f399cjt32598 for linux-mips-outgoing; Mon, 9 Apr 2001 02:38:45 -0700 Received: from mx.mips.com (mx.mips.com [206.31.31.226]) by oss.sgi.com (8.11.3/8.11.3) with ESMTP id f399cgM32593; Mon, 9 Apr 2001 02:38:42 -0700 Received: from newman.mips.com (ns-dmz [206.31.31.225]) by mx.mips.com (8.9.3/8.9.0) with ESMTP id CAA27903; Mon, 9 Apr 2001 02:38:45 -0700 (PDT) Received: from copfs01.mips.com (copfs01 [192.168.205.101]) by newman.mips.com (8.9.3/8.9.0) with ESMTP id CAA24516; Mon, 9 Apr 2001 02:38:42 -0700 (PDT) Received: from mips.com (copsun17 [192.168.205.27]) by copfs01.mips.com (8.9.1/8.9.0) with ESMTP id LAA22234; Mon, 9 Apr 2001 11:38:00 +0200 (MEST) Message-ID: <3AD182F7.FF740CA6@mips.com> Date: Mon, 09 Apr 2001 11:37:59 +0200 From: Carsten Langgaard X-Mailer: Mozilla 4.75 [en] (X11; U; SunOS 5.7 sun4u) X-Accept-Language: en MIME-Version: 1.0 To: Ralf Baechle CC: John Tobey , linux-mips@oss.sgi.com Subject: Re: 64-bit on Cobalt? References: <20010408184241.A3443@john-edwin-tobey.org> <20010409035453.B774@bacchus.dhis.org> Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: 7bit Sender: owner-linux-mips@oss.sgi.com Precedence: bulk Ralf Baechle wrote: > On Sun, Apr 08, 2001 at 06:42:41PM -0400, John Tobey wrote: > > > The CPU is a QED RM5231 (CONFIG_NEVADA) 150MHz. May I assume that > > nobody has run a 64-bit kernel on this thing? The RaQ has no video > > card but a serial console, PCI, IDE, Ethernet, and special LEDs, panel > > buttons, and LCD display. If I can get a 64-bit kernel to boot and > > prove its existence through any of these devices, I will be drunk with > > power. > > So far the only supported machine by the mips64 kernel is the SGI Origin > 200 / 2000 series. I have a QED RM5261 running a bigendian 64-bit kernel on our Malta board (it got a serial console, PCI, IDE, Ethernet). I haven't send the patch to Ralf yet, but you can get a snapshot at our kernel sources at ftp://ftp.mips.com/pub/linux/mips/kernel/2.4/src/linux-2.4.1.mips-src-01.00.tar.gz Hope it helps you. > > > The reason I want 64 bits is that I (a) want a challenge, (b) plan to > > write an application that uses a sparse address space (40 bits is > > better than 31), (c) plan to outlive the 31-bit time_t, and (d) am > > p.o.ed at having bought the thing based on misleading advertising that > > mentioned a 64-bit processor but not the 32-bit OS. > > > Big/little endian macht nichts. I guess big will be easier, and I'm > > not concerned with running any existing 32-bit binaries. > > Go for little endian because the firmware is little endian; supporting > ``other-endian'' for userspace would be unecessary extra pain. We already > have suport for 32-bit binaries in the 64-bit kernel; in fact ALL > software we run on 64-bit kernels is 32-bit. > > 32-bit wasn't only the easy thing to do - it's also the more efficient > thing for most software which doesn't need 64-bit registers or 64-bit > address space. For a system with a dog slow 32-bit memory bus such as > the Qube 64-bit kernels would mean a dramatic slowdown. > > I admit it's interesting though, mostly for engineering reasons, not > as a platform. > > > I imagine that I would start by grafting Cobalt's peripheral support > > code from arch/mips/cobalt (now defunct) and include/asm-mips/cobalt.h > > into the mips64 tree from cvs@oss.sgi.com:/cvs/linux. > > Somebody else was already working on upgrading the Cobalt kernel to 2.4. > > Ralf -- _ _ ____ ___ Carsten Langgaard Mailto:carstenl@mips.com |\ /|||___)(___ MIPS Denmark Direct: +45 4486 5527 | \/ ||| ____) Lautrupvang 4B Switch: +45 4486 5555 TECHNOLOGIES 2750 Ballerup Fax...: +45 4486 5556 Denmark http://www.mips.com