Re: [RFA/commit] arm-tdep.c: Do not single-step after hitting a watchpoint

Peter Maydell
2014-09-30T14:50:39Z

On 30 September 2014 15:26, Joel Brobecker <brobecker@adacore.com> wrote:
> That's very interesting. When I talked to one of our QEMU developers
> in house about this, he wasn't even sure if it was possible for
> QEMU to stop at the instruction triggering the watchpoint. Now,
> we know it is, but it could be simpler for QEMU to implement the
> same policy on all targets.

QEMU's stub has to implement "act like the hardware does" for
each individual target CPU, because that's what existing gdb
implementations in the field expect. "Act the same in the
stub regardless of target CPU" is what we used to do and
the result was not stopping in the right place.

The actual in-QEMU implementation is pretty trivial, since
we already need to support both behaviours in order to
correctly emulate the architectural debug support we
expose to guest OSes, and it's then just a matter of
setting or not setting a flag when we set up the wp.

-- PMM