PowerPC exceptions and critical interrupts

Sebastian Huber sebastian.huber at embedded-brains.de
Mon Jun 9 13:21:52 UTC 2008

I adapt the gen83xx BSP for the MPC8313E currently. I switched to the 
new support code (libcpu/powerpc/new-exceptions/bspsupport) and adjusted 
it for e300 cores. With this framework it is possible to use RTEMS 
routines and the dispatcher from external and critical exceptions (some 
sophisticated lock variables are involved for this).  In order too test 
it I configured the interrupt controller (IPIC) in a way so that for 
some interrupt sources a critical interrupt exception will be generated. 
This works fine except that the current rtems_interrupt_{enable,disable} 
functions are not aware of critical interrupts. This leads to race 
conditions in the system core. I guess that this is also true for Book E 
critical interrupts. A solution is to add the appropriate bits to the 
disable mask (MSR_CE or MSR_E300_CE), but this leads to a preprecessor 
or runtime cpu check orgie. Do we really need RTEMS support in critical 
or machine check exceptions?


Sebastian Huber, Embedded Brains GmbH

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E-Mail  : sebastian.huber at embedded-brains.de
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