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From: Keith Owens <kaos@ocs.com.au>
To: haba@pdc.kth.se (Harald Barth), linux-kernel@vger.kernel.org
Subject: Re: Size of pointers in sys_call_table? 
In-Reply-To: Your message of "Tue, 28 Aug 2001 17:17:24 +0100."
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Date: Wed, 29 Aug 2001 10:49:32 +1000
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On Tue, 28 Aug 2001 17:17:24 +0100 (BST), 
Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
>> The layout of the sys_call_table is totally architecture dependant.  The
>> question to ask here is why do you need to use it?  Modifying it to hook
>> into syscalls is frowned upon.
>
>And potentially unsafe (think about caching, and non atomic writes on
>some platforms)

Not forgetting architectures like PPC64 and IA64 that require a
different function pointer format when syscall code is in a module.  A
simple replacement of a pointer in the syscall table will not work on
those architectures.