Hi Gabe,

Thanks for your response. The information of user- vs. system-mode accesses
used to be available in GEMS. I don't see why this cannot be made available
in gem5, right?

--Carole

On Sun, Aug 7, 2011 at 10:26 PM, Gabriel Michael Black <
[email protected]> wrote:

> I don't think it is. When an instruction executes, it puts together a
> memory request and hands that to the CPU. The CPU uses the TLB defined by
> the ISA to translate the request which is where a decision is made about
> whether the access is allowed. If the TLB didn't decide there needs to be a
> fault, the CPU takes the request and uses it to generate one or more packets
> which it sends into the memory system to access the data. The packet itself
> is more or less just a transaction on the memory system and doesn't have to
> involve a processor at all. A request has more information like that, but it
> still doesn't have any information about the mode of the CPU. The TLB makes
> decisions about the request potentially using the mode, but that's about as
> close as it gets.
>
> Gabe
>
>
> Quoting Carole-Jean Wu <[email protected]>:
>
>  Hi Nilay,
>>
>> Thanks for your response. Do you know where the processor info is used to
>> create a packet specifically?
>>
>> Thanks,
>> Carole
>>
>> On Sun, Aug 7, 2011 at 11:56 AM, Nilay Vaish <[email protected]> wrote:
>>
>>  On Sat, 6 Aug 2011, Carole-Jean Wu wrote:
>>>
>>>  Hi,
>>>
>>>>
>>>> I am studying the interaction between user-mode and system-mode memory
>>>> reference using gem5. I am finding that all references are passed in as
>>>> supervisor mode references in system/RubyPort.cc recv_timing.
>>>>
>>>> As a result, the information of RubyAccessMode is loss after the request
>>>> leaves processor issue engine.
>>>>
>>>> Does anyone know how to appropriate set the RubyAccessMode in
>>>> RubyPort.cc
>>>> to
>>>> make this field hold valid information?
>>>>
>>>>
>>>>  RubyRequest is created using a packet, so the packet should have the
>>> information on the mode of the processor. I do not know if it has the
>>> info,
>>> but if this info exists with the processor that generated the packet,
>>> then
>>> it is easy to pass it in the packet.
>>>
>>> --
>>> Nilay
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>>>
>>>
>>
>
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