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Date: Tue, 03 Apr 2007 17:16:32 -0700
From: Peter Grehan <grehan@freebsd.org>
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Cc: freebsd-ppc@freebsd.org
Subject: Re: Exception in openfirmware calling
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> I've used the ofw_stack code from NetBSD for now. It creates a new
> stack with a real address.

  That will work, though I don't like the way it's implemented: the 
calls in all of the OFW routines is a little ugly. My plan was to have a 
call_onstack() routine that would allow a function to be executed on a 
specified stack. This can be used in other places too, such as when the 
initial thread has to switch over to it's allocated stack.

> Unfortunately there is still an exception in an address that looks like
> it is from openfirmware [1].

  DAR  0xD575A998

  That looks like a kernel virtual address: is it possible that a stack 
parameter is still getting through ? The BSD OFW routines try and 
allocate their parameters in bss (which should be 1:1 mapped), but 
sometimes a buffer will get passed through: e.g. a read/write.

later,

Peter.