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Date: Mon, 9 Nov 2009 20:15:47 -0500
From: Josh Boyer <jwboyer@linux.vnet.ibm.com>
To: Jonathan Haws <Jonathan.Haws@sdl.usu.edu>
Subject: Re: Invalidate Data Cache from User Space
Message-ID: <20091110011547.GD30489@zod.rchland.ibm.com>
References: <BB99A6BA28709744BF22A68E6D7EB51F03310AFEC3@midas.usurf.usu.edu>
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On Mon, Nov 09, 2009 at 11:10:42AM -0700, Jonathan Haws wrote:
>All,
>What is happening is the dcbi instruction will fail.  I get an Illegal Instruction message on the console and my program exits.
>
>Is there a reason I cannot call dbci from a user space application, or is there something wrong in my code?  Even better, is there a working and tested function that I can call from user space to invalidate a portion of the data cache?

dcbi is a priviledged instruction on 4xx.  You can only execute it from
supervisor mode (kernel).

josh