Examining the Translation Tables

Hi,
I need to examine the translation tables to find the configuration of
the Memory Space.  I do not find any techniques for debugging the MMU
in Arm Reference Manual.
How to do it ?

Thx in advans,
Karthik Balaguru

On 17 Jan 2007 21:49:54 -0800, "karthikbg"
<karthik.balaguru@lntinfotech.com> wrote:

>Hi,
>I need to examine the translation tables to find the configuration of
>the Memory Space.  I do not find any techniques for debugging the MMU
>in Arm Reference Manual.

I don't know about Arm, but in some hardware, the memory mapping
registers are write only, so you need to keep track what the OS writes
to these registers. 

Some OS might even keep an image copy of the mapping registers in
normal kernel RAM. You should exam these data structures. Any decent
OS should have primitives for querying about the memory usage.

If everything else fails, just look what the OS writes into the actual
hardware register.

Paul

Paul Keinanen wrote:
> On 17 Jan 2007 21:49:54 -0800, "karthikbg"
> <karthik.balaguru@lntinfotech.com> wrote:
>
> >Hi,
> >I need to examine the translation tables to find the configuration of
> >the Memory Space.  I do not find any techniques for debugging the MMU
> >in Arm Reference Manual.
>
> I don't know about Arm, but in some hardware, the memory mapping
> registers are write only, so you need to keep track what the OS writes
> to these registers.
>
> Some OS might even keep an image copy of the mapping registers in
> normal kernel RAM. You should exam these data structures. Any decent
> OS should have primitives for querying about the memory usage.
>
> If everything else fails, just look what the OS writes into the actual
> hardware register.
>
> Paul

I need to do MMU table walks and debug MMU. ( ARM926EJ-S ) .
I use CCS(Code Composer Studio) & JTAG.  Kindly tell me some
ideas/solutions 
for this.

Thx in advans,
Karthik Balaguru

"karthikbg" <karthik.balaguru@lntinfotech.com> wrote:

>
>Paul Keinanen wrote:
>> On 17 Jan 2007 21:49:54 -0800, "karthikbg"
>> <karthik.balaguru@lntinfotech.com> wrote:
>>
>> >Hi,
>> >I need to examine the translation tables to find the configuration of
>> >the Memory Space.  I do not find any techniques for debugging the MMU
>> >in Arm Reference Manual.
>>
>> I don't know about Arm, but in some hardware, the memory mapping
>> registers are write only, so you need to keep track what the OS writes
>> to these registers.
>>
>> Some OS might even keep an image copy of the mapping registers in
>> normal kernel RAM. You should exam these data structures. Any decent
>> OS should have primitives for querying about the memory usage.
>>
>> If everything else fails, just look what the OS writes into the actual
>> hardware register.
>>
>> Paul
>
>I need to do MMU table walks and debug MMU. ( ARM926EJ-S ) .
>I use CCS(Code Composer Studio) & JTAG.  Kindly tell me some
>ideas/solutions 
>for this.
>
>Thx in advans,
>Karthik Balaguru

You need to read the Translation Table Base Register at CP15, Register 2
This contains a pointer to the First Level Page Table.

 CP-15  is used to set MMU  Memory Mapping

werty wrote:
> CP-15  is used to set MMU  Memory Mapping

Thx for your info. I find that some Debuggers are capable of performing
MMU table walks, for debugging in virtual memory environments .
Kindly let me know if CCS (Code Composer Studio) supports it and
provide me with some links/docs that explains it.

Thx in advans,
Karthik Balaguru

karthikbg <karthik.balaguru@lntinfotech.com> wrote:
> Thx for your info. I find that some Debuggers are capable of performing
> MMU table walks, for debugging in virtual memory environments .
> Kindly let me know if CCS (Code Composer Studio) supports it and
> provide me with some links/docs that explains it.

I suggest you ask your vendor's support. Texas Instruments in this case.

-p
-- 
"Unix is user friendly, it's just picky about who its friends are."
 - Anonymous
--------------------------------------------------------------------

 I am the fastest systems programmer on earth and
 I know everything about
  JumpTables ,
  paging and protection and
  LDT's and  GDT's and
  GPF's

  but your unintuitive

   TABLE WALK  is ambigous ...


    Explain please ..
___________________________________________________



karthikbg wrote:
> werty wrote:
> > CP-15  is used to set MMU  Memory Mapping
>
> Thx for your info. I find that some Debuggers are capable of performing
> MMU table walks, for debugging in virtual memory environments .
> Kindly let me know if CCS (Code Composer Studio) supports it and
> provide me with some links/docs that explains it.
> 
> Thx in advans,
> Karthik Balaguru

werty wrote:
>  I am the fastest systems programmer on earth and
>  I know everything about
>   JumpTables ,
>   paging and protection and
>   LDT's and  GDT's and
>   GPF's
> 
>   but your unintuitive
> 
>    TABLE WALK  is ambigous ...
> 
> 
>     Explain please ..


beware the troll: http://tinyurl.com/2etcbc