On Mon, 2014-05-26 at 15:20 -0700, shiva7 wrote: > 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?
I think you'll need to debug it, and send a patch if you find a bug. As for "in general" that depends on whether your application cares about the difference in semantics that was noted. -Scott _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
