Re: [PATCH 00/15] powerpc/watchpoint: Preparation for more than one watchpoint

[Ravi Bangoria]

On 3/18/20 6:22 PM, Ravi Bangoria wrote:
> On 3/16/20 8:35 PM, Christophe Leroy wrote:
> > Le 09/03/2020 Ã 09:57, Ravi Bangoria a ÃcritÂ:
> > > So far, powerpc Book3S code has been written with an assumption of only
> > > one watchpoint. But future power architecture is introducing second
> > > watchpoint register (DAWR). Even though this patchset does not enable
> > > 2nd DAWR, it make the infrastructure ready so that enabling 2nd DAWR
> > > should just be a matter of changing count.
> >
> > Some book3s (e300 family for instance, I think G2 as well) already have a DABR2 in addition to DABR.
> > Will this series allow to use it as well ?
>
> I wasn't aware of that. I'll take a look at their specs and check if they
> can piggyback on this series for 2nd DABR.

There are some differences between G2/e300 DABRs and Book3S DAWRs. G2/e300
DABRs provides some functionalities like "Match if EA less/greater than DABR",
"combined mode" etc. are not present with DAWRs. DBCR on G2/e300 also provides
which DABR caused the exception. So this series might not directly allow to
use DABR2 but, I guess, it should work as base infrastructure.

Ravi