False positive permanent breakpoints

Ofir Cohen ofircohenn@gmail.com
Wed Oct 26 15:02:00 GMT 2016


> I'd rather that upstreaming that bit was done when the
> rest of the port is submitted as well.
Alright, will do.

As a temporary mitigation,
Is it OK for the target to return NULL from gdbarch_breakpoint_from_pc
to state that it doesn't support software breakpoints ?


There are some places that check that return value, like:
/* Software breakpoints unsupported?  */
if (bpoint == NULL)
  return 0;

in bp_loc_is_permanent(), and others that don't, like breakpoint_xfer_memory().
Furthermore, it performs pointer arithmetic based on the returned value.

Currently the tests we have pass, but I'm concerned about other corner
cases are not covered
that might pop up as a result of this change.

Thanks,
Ofir

On 26 October 2016 at 17:50, Pedro Alves <palves@redhat.com> wrote:
> On 10/26/2016 03:42 PM, Ofir Cohen wrote:
>> Hi Pedro,
>> Thanks for the reply.
>> Let me provide some clarifications :-).
>>
>> 1) The product is part of the "Intel SDK for OpenCL" [1] for Windows and Linux.
>>      You can see how it looks in [2].
>
> Ah, OK.
>
>>
>> 2) iGPU - Yes, Integrated GPU
>>
>> 3) Upstream is in our plans and actually we are preparing a clean
>>     series of patches on top of 7.12 (currently we are rebased on top
>> of 7.6, yeah I know...).
>
> Nice!
>
> (FAOD, for upstream you'll need to rebase on master.)
>
>>
>> 4) Software breakpoints are officially supported by the HW, but
>>     haven't been tested and used yet, so we're OK with them being
>> "disabled" at the moment.
>>
>> The sources for gdb (as well as other components) are provided with
>> the installer script,
>> which can be downloaded _free of charge_ via [1] --> "Download" .
>>
>> Is that good enough for making an upstream change?
>>
>> I can try and prepare a small patch.
>
> I'd rather that upstreaming that bit was done when the
> rest of the port is submitted as well.
>
> Thanks,
> Pedro Alves
>



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