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

Luis Machado
2014-09-29T17:57:22Z

On 09/29/2014 02:51 PM, Joel Brobecker wrote:
> Hello all,
>
>> Hmm. So when the data abort triggers at fault+8, the instruction
>> that triggered the abort hasn't actually completed, right? No memory
>> has changed yet.
>>
>> So if nothing does the adjustment, like Gareth found out happens with
>> the Black Magic Probe, then we'll resume execution from the
>> wrong address/instruction (with the effects of the skipped instructions
>> missing, including the memory write...). Did I understand that
>> right? (Gareth, is that what you see?)
>
> I have been trying to understand the various contributions, and
> I admit I am still not quite sure...
>
> Does it look like the patch I proposed is correct? It seems to be
> supported by Terry Guo's experiments as well...
>
> Thanks!
>

From previous mails, it does not seem to be correct for Linux, where
the ptrace interface adjusts the data fault address to point to the
address of the instruction that caused the trigger. So it looks like the
current behavior of GDB is correct for Linux, though it may not be
correct for QEMU or bare metal.

Luis