* Kernel function having physical address. how?
@ 2007-10-23 10:22 Barisa Kisku
2007-10-23 18:51 ` Scott Wood
0 siblings, 1 reply; 2+ messages in thread
From: Barisa Kisku @ 2007-10-23 10:22 UTC (permalink / raw)
To: linuxppc-embedded
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hi,
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.Kernelis 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.
Does u-boot do this when uncompressing and loading the kernel. Please
comment.
thanks in advance.
Barisa
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^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: Kernel function having physical address. how?
2007-10-23 10:22 Kernel function having physical address. how? Barisa Kisku
@ 2007-10-23 18:51 ` Scott Wood
0 siblings, 0 replies; 2+ messages in thread
From: Scott Wood @ 2007-10-23 18:51 UTC (permalink / raw)
To: Barisa Kisku; +Cc: linuxppc-embedded
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
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2007-10-23 10:22 Kernel function having physical address. how? Barisa Kisku
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