[PATCH v2 0/3] Support --enable-newlib-reent-thread-local Newlib configuration option

[Sebastian Huber]

On 21.07.22 10:36, Chris Johns wrote:
> On 21/7/2022 6:30 pm, Sebastian Huber wrote:
>> On 21.07.22 10:27, Chris Johns wrote:
>>> On 21/7/2022 6:21 pm, Sebastian Huber wrote:
>>>> On 21.07.22 10:16, Chris Johns wrote:
>>>>> On 21/7/2022 6:11 pm, Sebastian Huber wrote:
>>>>>> On 21.07.22 10:03, Chris Johns wrote:
>>>>>>> As an aside, does gdb know about TLS variables and so will `errno` be
>>>>>>> visible?
>>>>>> Good question, there seems to be some support missing. For example for
>>>>>> arm/xilinx_zynq_a9_qemu:
>>>>>>
>>>>>> Breakpoint 7, Init (ignored=2118804) at
>>>>>> /home/EB/sebastian_h/src/rtems/testsuites/samples/fileio/init.c:1169
>>>>>> 1169      TEST_BEGIN();
>>>>>> (gdb) watch _tls_errno
>>>>>> Cannot find thread-local variables on this target
>>>>>> (gdb) p _tls_errno
>>>>>> Cannot find thread-local variables on this target
>>>>> I wonder if we need to configure gdb so it understands how we handle TLS
>>>>> variables?
>>>> It could be a Qemu issue. In GDB there is a
>>>>
>>>>         /* Check for the TLS register feature.  */
>>>>         feature = tdesc_find_feature (tdesc, "org.gnu.gdb.arm.tls");
>>>>
>>>> However, this is not provided by Qemu.
>>> Is this something in the remote protocol? I would have thought the ABI would
>>> define the register?
>> Yes, I guess this is a part of the machine description provided by the server
>> (Qemu). This stuff seems to be quite new (from 2022) added by John Baldwin for
>> FreeBSD.
> That would only apply if qemu was providing the XML description and it is not
> normally something I have seen. Most of time the built in XML is used.
> 
> The only packet I could see in a quick look at the protocol is offsets for TLS
> variables for dynamically loaded object files. This is needed because the link
> editor allocates the variables when relocating.

Maybe this feature is not included in GDB 12 and earlier?

-- 
embedded brains GmbH
Herr Sebastian HUBER
Dornierstr. 4
82178 Puchheim
Germany
email: sebastian.huber at embedded-brains.de
phone: +49-89-18 94 741 - 16
fax:   +49-89-18 94 741 - 08

Registergericht: Amtsgericht München
Registernummer: HRB 157899
Vertretungsberechtigte Geschäftsführer: Peter Rasmussen, Thomas Dörfler
Unsere Datenschutzerklärung finden Sie hier:
https://embedded-brains.de/datenschutzerklaerung/