Another question about L4 system call

Bob <[email protected]> Fri, 5 Sep 2008 12:14:13 +0800 (CST)

Newsgroups	gmane.comp.micro-kernel.l4.l4ka.general
Message-ID	<18388042.147181220588053884.JavaMail.coremail@bj163app137.163.com>

 
 Hi, All

I have another question about L4 system call.
I think all system call are implemented in system space. So only enter system level can execute it. 

Now I saw the code just jmp to the system call address getted from kip_area. And then will 
use "int SYSCALL_NUMBER" instruction enter system level or not.

But the system call address getted from kip_area is in system space. If don't enter system level first, isn't there a page fault will occur?

Anyone could tell me why ?


Thank you  very much !

Bob