Hi,
I'm trying to wrap my head around how linux handles branch tracing on
Book III-E. I think I understand how we set MSR[DE] and DBCR0[IDM|BT],
and how we handle fixing things up if an instruction being traced causes
an exception.
I have a few questions though:
1) Does user_enable_block_step() have a bug in it? The current code has
task->thread.dbcr0 = DBCR0_IDM | DBCR0_BT;
Should that be as follows (to match the singel-step case)?
task->thread.dbcr0 |= DBCR0_IDM | DBCR0_BT;
2) Why doesn't DBCR0_ACTIVE_EVENTS include DBCR0_BT?
3) In sys_debug_setcontext() why does SIG_DBG_BRANCH_TRACING return
-EINVAL if CONFIG_PPC_ADV_DEBUG_REGS is set? Would it not be possible
to use DBCR0_BT?
Thanks,
Chris
--
Chris Friesen
Software Designer
500 Palladium Drive, Suite 2100
Ottawa, Ontario K2N 1C2, Canada
www.genband.com
office:+1.343.883.2717
chris.frie...@genband.com
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