From mboxrd@z Thu Jan  1 00:00:00 1970
From: Pedro Franco de Carvalho <pedromfc@linux.vnet.ibm.com>
Date: Fri, 16 Mar 2018 20:53:04 +0000
Subject: Re: [PATCH] powerpc: Disable DAWR on POWER9
Message-Id: <87po434ua7.fsf@linux.vnet.ibm.com>
List-Id: <kvm-ppc.vger.kernel.org>
References: <20180316025456.24036-1-mikey@neuling.org>
In-Reply-To: <20180316025456.24036-1-mikey@neuling.org>
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To: kvm-ppc@vger.kernel.org


Michael Neuling <mikey@neuling.org> writes:

> For ptrace, we now return an error if run on a POWER9. GDB gives this
> error when you attempt to run a program with a breakpoint set on
> POWER9:
>   "Unexpected error setting breakpoint or watchpoint: No such device."

Thanks a lot for implementing this!

Would it also make sense to have PPC_PTRACE_GETHWDBGINFO return
dbginfo.num_data_bps = 0 if !breakpoint_available()? In this case GDB
would work in a friendlier way, because it would transparently switch to
software watchpoints.

Not sure what to do about .features in this case. I assume currently it
only has PPC_DEBUG_FEATURE_DATA_BP_RANGE set and not the DAWR feature
flag (since the cpu feature is disabled).

Thanks!
Pedro