Re: Arm userland not building with gcc-9 and later

[Philippe Gerum <rpm@xenomai.org>]

Jan Kiszka <jan.kiszka@siemens.com> writes:

> On 08.08.21 19:21, Philippe Gerum wrote:
>> 
>> Jan Kiszka <jan.kiszka@siemens.com> writes:
>> 
>>> On 07.08.21 19:00, Philippe Gerum wrote:
>>>>
>>>> Jan Kiszka <jan.kiszka@siemens.com> writes:
>>>>
>>>>> Hi all,
>>>>>
>>>>> just wanted to debug the RTnet issues we now see in CI on arm and arm64.
>>>>> I picked arm as first target, but that apparently starts to break with
>>>>> gcc-9 or newer (tried 9.2 and 10.2):
>>>>>
>>>>> make[5]: Entering directory '/xenomai/lib/cobalt/arch/arm'
>>>>>   CC       libarch_la-features.lo
>>>>> features.c: In function 'cobalt_arch_check_features':
>>>>> features.c:82:1: error: r7 cannot be used in 'asm' here
>>>>>    82 | }
>>>>>       | ^
>>>>>
>>>>> That seems to be related to passing the syscall number via r7 on ARM. Is
>>>>> our ABI soon no longer compilable, or can we fix this?
>>>>>
>>>>
>>>> Just tried to reproduce this issue with the latest stable (10.3-2021.07)
>>>> from ARM [1], and a fairly recent linaro snapshot (11.0.1-2021.03) [2],
>>>> to no avail. I tried with --enable-debug=symbols, --disable-debug,
>>>> --enable-debug=full, no issue so far.
>>>>
>>>> Can you please share you configure settings?
>>>
>>> I'm on ARM gcc 10.3-2021.07 as well. Debian's gcc from bullseye show 
>>> this, too.
>>>
>>> ./configure --host=arm-none-linux-gnueabihf --enable-debug=full
>>>
>>> on master. And that results in
>>>
>>>   CC       libarch_la-features.lo
>>> ../../../../../lib/cobalt/arch/arm/features.c: In function ‘cobalt_arch_check_features’:
>>> ../../../../../lib/cobalt/arch/arm/features.c:82:1: error: r7 cannot be used in ‘asm’ here
>>>    82 | }
>>>       | ^
>>>
>> 
>> Confirmed, found it. next is fine with this compiler, which is the
>> version I tested. However, building stable and master does break.
>> 
>
> Yeah, I've already pushed the two related fixes into next for testing.
> Can still be changed if we find a better solution.
>

Ack.

-- 
Philippe.