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Date: Sun, 19 May 2002 12:23:37 -0700
From: Ralf Baechle <ralf@oss.sgi.com>
To: Matthew Dharm <mdharm@momenco.com>
Cc: Linux-MIPS <linux-mips@oss.sgi.com>
Subject: Re: MIPS 64?
Message-ID: <20020519122336.A20670@dea.linux-mips.net>
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In-Reply-To: <NEBBLJGMNKKEEMNLHGAIOEPPCGAA.mdharm@momenco.com>; from mdharm@momenco.com on Wed, May 15, 2002 at 02:34:47PM -0700
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On Wed, May 15, 2002 at 02:34:47PM -0700, Matthew Dharm wrote:

> So... I'm looking at porting Linux to a system with 1.5GiB of RAM.
> That kinda blows the 32-bit MIPS port option right out of the water...

Not really, there is still highmem though that certainly a sucky solution
as compared to a 64-bit kernel.

> What does it take to do a 64-bit port?  The first problem I see is the
> boot loader -- do I have to be in 64-bit mode when the kernel starts,
> or can I start in 32-bit mode and then transfer to 64-bit mode?

Same loader as before - the build procedure will result in a 32-bit kernel
binary which is loaded to the same old KSEG0 addresses.

> I looked in the arch/mips64/ directory, but I don't see much for
> specific boards there, but there are references to the Malta
> boards....

Exactly.  The aim is to support both kernels without replicating the board
support code.

  Ralf