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Subject: Re: ring on PowerPC
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Grant Likely <grant.likely@secretlab.ca>
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Date: Wed, 31 Oct 2007 16:36:36 +1100
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On Tue, 2007-10-30 at 23:18 -0600, Grant Likely wrote:
> On 10/30/07, Bai Shuwei <baishuwei@gmail.com> 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!
> 
> Powerpc has 2 privilege levels; user and supervisor.  The kernel runs
> in supervisor mode, and user-space runs in user mode.

To be complete here, some implementations have 3 :-) Don't forget
hypervisor mode !

Ben.