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Date: Wed, 27 Apr 2005 09:04:48 +1000
From: Paul Mackerras <paulus@samba.org>
To: "Stuart Yoder" <stuart.yoder@conformative.com>
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Cc: 'linuxppc-dev list' <linuxppc-dev@ozlabs.org>
Subject: RE: PowerPC + SMP
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Stuart Yoder writes:

> That raises a question though-- how can I know what assumptions the
> kernel makes about the state of the CPU/system when it begins execution?
> Is this clearly documented anywhere?

In general the kernel assumes that firmware has set up the HID
registers, caches, northbridge, memory controller, memory, etc., in a
suitable state for the machine to run at full speed.  There is code to
set and clear various HID bits, depending on the specific cpu model -
look for the __setup_cpu_* functions in arch/ppc/kernel/*.S.  I guess
we could add code to set ABE and SYNCBE on 7447A processors on SMP
systems; I can't imagine that any SMP system would require them to be
clear.

Paul.