Re: warning: Target-supplied registers are not supported by the current architecture

On 10/9/23 11:46, William Tambe via Gdb wrote:
> On Mon, Oct 9, 2023 at 1:45 AM Aktemur, Tankut Baris
> <[email protected]> wrote:
>>
>> On Monday, October 9, 2023 1:14 AM, William Tambe wrote:
>>> I am working on gdbserver support.
>>>
>>> I am able to remotely execute the executable and set breakpoints,
>>> however right after issuing the `target remote` command, I am getting
>>> following warning:
>>>
>>> (gdb) target remote 192.168.1.164:2000
>>> Remote debugging using 192.168.1.164:2000
>>> warning: Target-supplied registers are not supported by the current architecture
>>>
>>> Error message is coming from gdb/target-descriptions.c at line 576,
>>> due to data->arch_regs.empty () return true.
>>>
>>> Any idea what I might have missed causing data->arch_regs.empty () to
>>> return true ?
>>
>> When gdbserver is started with the --remote-debug flag, it prints the
>> received and sent RSP packages.  There, the target description XML would
>> be seen.  I'd suggest starting with inspecting if the contents of that XML
>> look right.
> 
> Below snippet of the prints when using --remote-debug shows the target
> description XML.
> I see a star in front of <reg name ... /> blocks; any idea whether
> that could be the issue ?
> In the source code, I am not using an actual XML file, instead, I am
> manually building the target description XML through calls to
> tdesc_create_reg:
> https://github.com/fontamsoc/binutils-gdb/blob/main/gdbserver/linux-pu32-low.cc#L63
> 
> [remote] getpkt: getpkt ("qXfer:features:read:target.xml:0,1000");
> [no ack sent]
> [remote] putpkt_binary_1: putpkt ("$l<?xml version="1.0"?>
> <!DOCTYPE target SYSTEM "gdb-target.dtd">
> <target>
>   <architecture>pu32</architecture>
>   <osabi>GNU/Linux</osabi>
>   <feature name="org.gnu.gdb.pu32.core">
>  * <reg name="r0" bitsize="32" type="uint32" regnum="0"/>
>  * <reg name="r1" bitsize="32" type="uint32" regnum="1"/>
>  * <reg name="r2" bitsize="32" type="uint32" regnum="2"/>
>  * <reg name="r3" bitsize="32" type="uint32" regnum="3"/>
>  * <reg name="r4" bitsize="32" type="uint32" regnum="4"/>
>  * <reg name="r5" bitsize="32" type="uint32" regnum="5"/>
>  * <reg name="r6" bitsize="32" type="uint32" regnum="6"/>
>  * <reg name="r7" bitsize="32" type="uint32" regnum="7"/>
>  * <reg name="r8" bitsize="32" type="uint32" regnum="8"/>
>  * <reg name="r9" bitsize="32" type="uint32" regnum="9"/>
>  * <reg name="r10" bitsize="32" type="uint32" regnum="10"/>
>  * <reg name="r11" bitsize="32" type="uint32" regnum="11"/>
>  * <reg name="r12" bitsize="32" type="uint32" regnum="12"/>
>  * <reg name="r13" bitsize="32" type="uint32" regnum="13"/>
>  * <reg name="r14" bitsize="32" type="uint32" regnum="14"/>
>  * <reg name="r15" bitsize="32" type="uint32" regnum="15"/>
>  * <reg name="pc" bitsize="32" type="uint32" regnum="16"/>
>   </feature>
> </target>
> #ae"); [noack mode]
> [remote] getpkt: getpkt ("qXfer:auxv:read::0,1000");  [no ack sent]
> 
> 
> Any ideas on what I am doing wrong ?

What architecture is this out of curiosity? Are you enabling a new architecture called pu32?