VMA of processes and CPU registers

[Prabhu nath]

My Apologies for top posting. Now in continuation to my previous question.
Is there a method to know whether segmentation unit is enabled or disabled
either from Kernel space or user space.

Thanks,
Prabhu


On Mon, Apr 25, 2011 at 10:08 PM, mindentropy <mindentropy at gmail.com> wrote:

> On Monday 25 Apr 2011 2:25:10 pm Prabhu nath wrote:
> > I understand about Linear virtual address and Physical address. How is
> the
> > logical address generated ? Can you please explain.
> >
> > Thanks,
> > Prabhu
> >
> > On Wed, Apr 20, 2011 at 9:33 PM, mindentropy <mindentropy at gmail.com>
> wrote:
> > > On Wednesday 20 Apr 2011 4:31:08 pm limp wrote:
> > > > Thanks a lot Dace and Vladimir for your replies.
> > > >
> > > > First of all, I forgot to mention that I am talking for x86
> > > > architecture.
> > > >
> > > > > The CPU registers will contain the virtual addresses. Each and
> every
> > > > > time that the CPU tries to access a virtual memory location, then
> the
> > > > > address will be translated by the MMU into a physical address.
> > > >
> > > > So, AFAIU the translation to physical memory takes place *only* when
> > > > the ALU of the processor has to do some operation which has memory
> > > > operands (in this case the CPU needs to deal with the *real*
> > > > addresses) but not prior to that.
> > >
> > > The address translation happens in the following way:
> > >
> > > Logical Addr-->|Segmentation Unit|-->Linear Addr -->|Paging unit|-->
> > > Physical
> > > Addr.
> > >
> > > If the paging unit is not setup then the linear addr is the physical
> > > addr.
> > >
> > > _______________________________________________
> > > Kernelnewbies mailing list
> > > Kernelnewbies at kernelnewbies.org
> > > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
> In the segmented memory model the memory appears as segments. In this model
> the program issues a logical address which comprises of a segment:offset
> address. The offset selects a byte in the segment. The segmentation unit
> converts it to a linear address. If the paging unit is enabled the linear
> address passes through the paging unit for further translation.
>
>
> Also please do not top post :)
>
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