questions on CONFIG_PPC_ADV_DEBUG_REGS, DBCR0_BRT, and DBCR0_ACTIVE_EVENTS

[shiva7]

shiva7 wrote
> Thanks again Scott.
/
>> Any idea whether the DBCR0 BRT bit actually works(??), 
> 
>> Do you have reason to believe that it might not? 
/
> 
> I'm facing a strange problem which was not there on server processor. Let
> me try to give brief flow.
> 
> Server :
> 
> Set BE bit (thru system call or sigreturn) for specific thread -> for
> every branch -> trace exception -> Normal exception prolog
> (STD_EXCEPTION_COMMON) SRR0 and SRR1
> 
> Embedded/BOOKE:
> 
> Set DE & BRT bit (thru system call or sigreturn) for specific thread ->
> for every branch taken -> Debug exception -> DEBUG_DEBUG prolog ->
> return_dbg_except DSRR0 & DSRR1
> 
> In server case, able to capture the branches as expected, but wherein
> BOOKE though branch taken exception are generated, at the certain stage
> (mostly after turn on BRT & DE bit)  user process is deviated (not taking
> the same flow as like server) and leading to different
> corruption/unexpected behavior.
/
>> And also, anything special required for "server" family application code 
>> porting here ?? as because in server family the trace exception used to
>> viz 
>> NORMAL exception proglog and uses SRR0 and SRR1 but in this ISA/embedded 
>> case have dedicated DEBUG_DEBUG prolog and dedicated registers DSRR0 and 
>> DSRR1. 
> 
>> IIRC the branch taken mechanism does have different semantics than the 
>> equivalent mechanism on server.  You can find discussion of this in the 
>> archives. :-) 
/
> 
> Most of the discussions so far I have surfed are related to branch
> taken/fall through(not taken) semantics related. But, in general, if I
> have an application running on server where tracing was based on BE bit
> and same can run on e500mc with DE & BRT combination?
> 
> 
> Thanks In Advance.

Could someone help on this regard?




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