docs: remote protocol: bc/bs not mentioned in stop-reply list

docs: remote protocol: bc/bs not mentioned in stop-reply list

[Matheus Tavares Bernardino]

Hi,

The remote protocol docs for stop-reply [1] has a list of commands
that accept stop-reply packets as a response:

"The 'C', 'c', 'S', 's', 'vCont', 'vAttach', 'vRun', 'vStopped', and
'?' packets can receive any of the below as a reply."

However, at the definition of 'bc' and 'bs' [2], it's also said:

"Reply: See Stop Reply Packets, for the reply specifications."

Maybe the list from [1] is not meant to be exhaustive, but perhaps
'bc' and 'bs' could be added to it?

[1]: https://sourceware.org/gdb/onlinedocs/gdb/Stop-Reply-Packets.html
[2]: https://sourceware.org/gdb/onlinedocs/gdb/Packets.html#Packets

Thanks,
Matheus

Re: docs: remote protocol: bc/bs not mentioned in stop-reply list

[Luis Machado]

On 6/28/23 13:06, Matheus Tavares Bernardino via Gdb wrote:
> Hi,
> 
> The remote protocol docs for stop-reply [1] has a list of commands
> that accept stop-reply packets as a response:
> 
> "The 'C', 'c', 'S', 's', 'vCont', 'vAttach', 'vRun', 'vStopped', and
> '?' packets can receive any of the below as a reply."
> 
> However, at the definition of 'bc' and 'bs' [2], it's also said:
> 
> "Reply: See Stop Reply Packets, for the reply specifications."
> 
> Maybe the list from [1] is not meant to be exhaustive, but perhaps
> 'bc' and 'bs' could be added to it?
> 
> [1]: https://sourceware.org/gdb/onlinedocs/gdb/Stop-Reply-Packets.html
> [2]: https://sourceware.org/gdb/onlinedocs/gdb/Packets.html#Packets
> 
> Thanks,
> Matheus

It seems those two commands actions, bc (backwards continue) and bs (backwards step), were never implemented in gdbserver.

I wasn't aware they existed at all. The fact they are not properly documented might mean they aren't actually used that much.

Do you have a remote debugging stub that can do reverse continue/step over the RSP?

Re: docs: remote protocol: bc/bs not mentioned in stop-reply list

[Matheus Tavares Bernardino]

On Wed, Jun 28, 2023 at 9:14 AM Luis Machado <luis.machado@arm.com> wrote:
>
> It seems those two commands actions, bc (backwards continue) and bs (backwards step), were never implemented in gdbserver.
>
> I wasn't aware they existed at all. The fact they are not properly documented might mean they aren't actually used that much.
>
> Do you have a remote debugging stub that can do reverse continue/step over the RSP?

This was originally reported at the QEMU mailing list:
https://lore.kernel.org/qemu-devel/20230623035304.279833-1-npiggin@gmail.com/t/#u

Re: docs: remote protocol: bc/bs not mentioned in stop-reply list

[Luis Machado]

On 6/29/23 09:08, Matheus Tavares Bernardino wrote:
> On Wed, Jun 28, 2023 at 9:14 AM Luis Machado <luis.machado@arm.com> wrote:
>>
>> It seems those two commands actions, bc (backwards continue) and bs (backwards step), were never implemented in gdbserver.
>>
>> I wasn't aware they existed at all. The fact they are not properly documented might mean they aren't actually used that much.
>>
>> Do you have a remote debugging stub that can do reverse continue/step over the RSP?
> 
> This was originally reported at the QEMU mailing list:
> https://lore.kernel.org/qemu-devel/20230623035304.279833-1-npiggin@gmail.com/t/#u

I chatted with Alex B. and it seems it's been used in QEMU for a while. So it does seem like a case of
the documentation not being very precise/exhaustive. Should be easy enough to change.