AnsweredAssumed Answered

Regarding PVR register access from user space.

Question asked by Simbu on Oct 23, 2012
Latest reply on Oct 24, 2012 by Scott Wood

Hi All,

 

I'm facing one bottleneck in using the mfpvr instruction on e500mc hardware (user space). This instruction/register execution/access is supervisor privilage, so register

access from user space should lead to illegal instruction.

 

We I tried to access this PVR register from user space, the app is able to get the PVR value without extra provisioning.When I checked more from

Kernel perspective identified one procedure (eumulate_instructio) in traps.c which is emulating the program exceptions

irrespective of user/kernel mode.

 

I have following queries:

 

--> Is this kind of emulation is configurable one?? ( I don't see any compile time MACRO for PVR register).

--> Any idea why there is no check placed to make sure the process (user level) has signal handler defined for illegal instructions which is about to emulate?

--> How can remove such dependencies from Kernel ( I don't want the Kernel to perform any extra job like emulation)

 

Thanks in Advance.


Outcomes