From mboxrd@z Thu Jan  1 00:00:00 1970
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 <87y29d42bm.fsf@xenomai.org>
 <b8fd767c-9adc-4fba-ac5c-cdafb8f03e0b@siemens.com>
From: Philippe Gerum <rpm@xenomai.org>
Subject: Re: Arm userland not building with gcc-9 and later
In-reply-to: <b8fd767c-9adc-4fba-ac5c-cdafb8f03e0b@siemens.com>
Date: Sun, 08 Aug 2021 19:21:47 +0200
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To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Xenomai <xenomai@xenomai.org>, Greg Gallagher <greg@embeddedgreg.com>


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

> On 07.08.21 19:00, Philippe Gerum wrote:
>>=20
>> Jan Kiszka <jan.kiszka@siemens.com> writes:
>>=20
>>> 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?
>>>
>>=20
>> 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=3Dsymbols, --disable-debug,
>> --enable-debug=3Dfull, no issue so far.
>>=20
>> Can you please share you configure settings?
>
> I'm on ARM gcc 10.3-2021.07 as well. Debian's gcc from bullseye show=20
> this, too.
>
> ./configure --host=3Darm-none-linux-gnueabihf --enable-debug=3Dfull
>
> on master. And that results in
>
>   CC       libarch_la-features.lo
> ../../../../../lib/cobalt/arch/arm/features.c: In function =E2=80=98cobal=
t_arch_check_features=E2=80=99:
> ../../../../../lib/cobalt/arch/arm/features.c:82:1: error: r7 cannot be u=
sed in =E2=80=98asm=E2=80=99 here
>    82 | }
>       | ^
>

Confirmed, found it. next is fine with this compiler, which is the
version I tested. However, building stable and master does break.

--=20
Philippe.