Re: Is there single step debugging support being added to aarch64-linux?

[Prafull Suryawanshi <prafull dot net at gmail dot com>]

Thanks. Adding one. Will send it to gdb-patches.

-Prafull

On Mon, Jun 15, 2015 at 5:27 PM,  <pinskia@gmail.com> wrote:
>
>
>
>
>> On Jun 15, 2015, at 4:48 AM, Prafull Suryawanshi <prafull.net@gmail.com> wrote:
>>
>> I am not sure why hw stepper not works here (might be limitation of hw
>> I am using).
>> That is may be the infrun loops as it never gets stop signal. (the
>> output I earlier pasted).
>> Is it ok to provide patch for software single step like arm here?
>> (I am preparing one. It will have simulate aarch64 instruction set and
>> implement aarch64 version of functions of
>> arm_linux_software_single_step, arm_insert_single_step_breakpoint and
>> arm_get_next_pc.)
>
>
> We do need one but for stepping over ldxr/stxr pairs.
>
> Thanks,
> Andrew
>
>>
>> Thanks,
>> Prafull
>>
>>> On Mon, Jun 15, 2015 at 4:49 PM,  <pinskia@gmail.com> wrote:
>>>
>>>
>>>
>>>
>>>> On Jun 15, 2015, at 4:07 AM, Prafull Suryawanshi <prafull.net@gmail.com> wrote:
>>>>
>>>> I am using gdb to talk to kgdb, so is not issue with gdb?
>>>> gdb is not able to set software single step like it do for arm.
>>>> There is implementation for gdbarch_software_single_step_p in arm gdb
>>>> but not in aarch64 gdb.
>>>>
>>>> In fact, I had small implementation to get next_pc at fixed offset
>>>> (+4) and it starts working. (implementing full version)
>>>
>>>
>>> Why can't you use the hardware single stepper for kgdb?
>>>
>>> Thanks,
>>> Andrew
>>>
>>>>
>>>> Let me know.
>>>>
>>>> Thanks,
>>>> Prafull
>>>>
>>>>
>>>> On Mon, Jun 15, 2015 at 4:27 PM, Prafull Suryawanshi
>>>> <prafull.net@gmail.com> wrote:
>>>>> I am using kgdb and trying to do single step (software single step).
>>>>> I see that infrun loops. (I enabled remote_debug option and compiled
>>>>> gdb 7.7 as 7.9 has issue with connection)
>>>>>
>>>>> infrun: clear_proceed_status_thread (Thread 3462)
>>>>> infrun: clear_proceed_status_thread (Thread 3444)
>>>>> infrun: proceed (addr=0xffffffffffffffff, signal=GDB_SIGNAL_DEFAULT, step=1)
>>>>> infrun: resume (step=1, signal=GDB_SIGNAL_0), trap_expected=1, current
>>>>> thread [Thread 3462] at 0xffffffc00021014c
>>>>> Sending packet: $Hcd86#7d...Ack
>>>>> Packet received: OK
>>>>> Sending packet: $s#73...Ack
>>>>> infrun: wait_for_inferior ()
>>>>> Packet received: T05thread:0d86;
>>>>> infrun: target_wait (-1, status) =
>>>>> infrun:   42000 [Thread 3462],
>>>>> infrun:   status->kind = stopped, signal = GDB_SIGNAL_TRAP
>>>>> infrun: infwait_normal_state
>>>>> infrun: TARGET_WAITKIND_STOPPED
>>>>> Sending packet: $g#67...Ack
>>>>> Packet received:
>>>>> 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
>>>>> infrun: stop_pc = 0xffffffc000210150
>>>>> Sending packet: $mffffffc000210150,4#4d...Ack
>>>>> Packet received: fd030091
>>>>> Sending packet: $mffffffc00021014c,4#7f...Ack
>>>>> Packet received: fd7ba3a9
>>>>> Sending packet: $mffffffc000210150,4#4d...Ack
>>>>> Packet received: fd030091
>>>>> infrun: stepping inside range [0xffffffc00021014c-0xffffffc000210170]
>>>>> Sending packet: $Z0,ffffffc00021014c,4#c8...Ack
>>>>> Packet received: OK
>>>>> infrun: resume (step=1, signal=GDB_SIGNAL_0), trap_expected=0, current
>>>>> thread [Thread 3462] at 0xffffffc000210150
>>>>> Sending packet: $Hc0#db...Ack
>>>>> Packet received: OK
>>>>> Sending packet: $s#73...Ack
>>>>> infrun: prepare_to_wait
>>>>>
>>>>> Then I build the gdb using arch_dump enable option
>>>>> gdbarch_dump: gdbarch_software_single_step_p() = 0
>>>>>
>>>>> I see that in gdb code, function aarch64_linux_software_single_step not present.
>>>>>
>>>>> I guess above loop expected if aarch64_linux_software_single_step absent, right?
>>>>>
>>>>> Thanks,
>>>>> Prafull
>>>>>
>>>>>> On Mon, Jun 15, 2015 at 4:08 PM, Andreas Schwab <schwab@suse.de> wrote:
>>>>>> Prafull Suryawanshi <prafull.net@gmail.com> writes:
>>>>>>
>>>>>>> I am trying it on 64 bit armv8 system but not able to doit.
>>>>>>> Found issue in gdb source code and absence of this function in
>>>>>>> aarch64-linux-tdep.c file. Anyone knows if support getting added or
>>>>>>> not?
>>>>>>
>>>>>> The stepi command is working fine on aarch64.  What do you get if you
>>>>>> try it?
>>>>>>
>>>>>> Andreas.
>>>>>>
>>>>>> --
>>>>>> Andreas Schwab, SUSE Labs, schwab@suse.de
>>>>>> GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
>>>>>> "And now for something completely different."