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
thanks all
On 10/31/07, Wang, Baojun [off-list ref] wrote:
On Wednesday 31 October 2007 13:05:16, Bai Shuwei wrote：
quoted
Hi, everyone
As we know, the program on the X86 can run on the differnt ring(0, 1,
2,
quoted
3) and the linux kernel run in the ring 0 and user program in the ring
3.
quoted
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
--
Add: Tianshui South Road 222, Lanzhou, P.R.China
Tel: +86-931-8912025
Zip Code: 730000
URL: oss.lzu.edu.cn
Email: baishuwei@gmail.com, buroc@126.com