From: Scott Wood <scottwood@freescale.com>
To: Barisa Kisku <barisa.kisku@gmail.com>
Cc: linuxppc-embedded@ozlabs.org
Subject: Re: Kernel function having physical address. how?
Date: Tue, 23 Oct 2007 13:51:43 -0500 [thread overview]
Message-ID: <471E42BF.5090509@freescale.com> (raw)
In-Reply-To: <80bb1bc60710230322t17fa517bt324031195abced24@mail.gmail.com>
Barisa Kisku wrote:
> I have ported linux-2.6.20 in cutom board based on MPC860.Kernel
> with the KERNELBASE as default 0xc00000000. uImage is downloaded at
> some address and booted with "bootm" command.Kernel is uncompressed
> and loaded at 0x00000000.All the kernel function is now having
> physical address (e.g. 0x000020c8 instead of 0xc00020c8, which is
> given by compiler).I think this required, to run kernel before MMU is
> on, but how this change in assembled code happens.
There is no change in the code itself -- the kernel is merely careful to
avoid (or fix up) data references before the MMU is turned on (which
happens quite early).
> Does u-boot do
> this when uncompressing and loading the kernel.
No.
-Scott
prev parent reply other threads:[~2007-10-23 18:51 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-23 10:22 Kernel function having physical address. how? Barisa Kisku
2007-10-23 18:51 ` Scott Wood [this message]
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