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Date: Mon, 28 May 2007 21:28:30 +1000
From: Paul Mackerras <paulus@samba.org>
To: "Wang, Baojun" <wangbj@lzu.edu.cn>
Subject: Re: Is it possible to call a C function in
	transfer_to_handler(arch/ppc/kernel/entry.S)?
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References: <380406375.32007@eyou.net> <200705281730.39257.wangbj@lzu.edu.cn>
Cc: ppc-dev <linuxppc-dev@ozlabs.org>, Nicholas McGuire <der.herr@hofr.at>
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Wang, Baojun writes:

>   I'm sorry to ask this topic in this mailling list. I've spend more than 2 
> days try to add a C function call in transfer_to_handler(in 
> arch/ppc/kernel/entry.S) like this:

It's not going to work, because the MMU is off at this point.  It will
explode as soon as the C code tries to touch any external variable.

Paul.