Re: [PATCH v4 10/10] powerpc/watchpoint: Remove 512 byte boundary

Ravi Bangoria
2020-07-21T03:25:32Z

Hi Jordan,

On 7/20/20 12:24 PM, Jordan Niethe wrote:
> On Fri, Jul 17, 2020 at 2:11 PM Ravi Bangoria
> <ravi.bangoria@linux.ibm.com> wrote:
>>
>> Power10 has removed 512 bytes boundary from match criteria. i.e. The watch
>> range can cross 512 bytes boundary.
> It looks like this change is not mentioned in ISA v3.1 Book III 9.4
> Data Address Watchpoint. It could be useful to mention that in the
> commit message.

Yes, ISA 3.1 Book III 9.4 has a documentation mistake and hopefully it
will be fixed in the next version of ISA. Though, this is mentioned in
ISA 3.1 change log:

Multiple DEAW:
Added a second Data Address Watchpoint. [H]DAR is
set to the first byte of overlap. 512B boundary is
removed.

I'll mention this in the commit description.

> Also I wonder if could add a test for this to the ptrace-hwbreak selftest?

Yes, I already have a selftest for this in perf-hwbreak. Will send that soon.

Thanks,
Ravi