From: "Wang, Baojun" <wangbj@lzu.edu.cn>
To: linuxppc-embedded@ozlabs.org, "Bai Shuwei" <baishuwei@gmail.com>
Subject: Re: ring on PowerPC
Date: Wed, 31 Oct 2007 14:12:34 +0800 [thread overview]
Message-ID: <393873503.24962@eyou.net> (raw)
Message-ID: <200710311412.36584.wangbj@lzu.edu.cn> (raw)
In-Reply-To: <393807697.25590@lzu.edu.cn>
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On Wednesday 31 October 2007 13:05:16, Bai Shuwei wrote：
> Hi, everyone
> As we know, the program on the X86 can run on the differnt ring(0, 1, 2,
> 3) and the linux kernel run in the ring 0 and user program in the ring 3.
> And now I want to know wether there is a simple mechanism on the PowerPC
> architecture? thx all!
>
> best regards!
>
> Buroc
powerpc has a machine state register(MSR), bit MSR_PR present the current
privilege level, if msr & MSR_PR, then it's from user space, otherwise(msr &
MSR_PR == 0) it's kernel space.
besides, the linux implementation only use ring0 and ring3 under i386, ring0
is highest(kernel space), ring3 is lowest (userspace)
Wang
--
Wang, Baojun Lanzhou University
Distributed & Embedded System Lab http://dslab.lzu.edu.cn
School of Information Science and Engeneering wangbj@lzu.edu.cn
Tianshui South Road 222. Lanzhou 730000 .P.R.China
Tel:+86-931-8912025 Fax:+86-931-8912022
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next parent reply other threads:[~2007-10-31 6:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <393807697.25590@lzu.edu.cn>
[not found] ` <200710311412.36584.wangbj@lzu.edu.cn>
2007-10-31 6:12 ` Wang, Baojun [this message]
2007-10-31 7:09 ` ring on PowerPC Bai Shuwei
2007-10-31 5:05 Bai Shuwei
2007-10-31 5:18 ` Grant Likely
2007-10-31 5:36 ` Benjamin Herrenschmidt
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