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From:   Michael Ellerman <mpe@ellerman.id.au>
To:     Christophe Leroy <christophe.leroy@csgroup.eu>,
        Marco Elver <elver@google.com>
Cc:     Dmitry Vyukov <dvyukov@google.com>,
        "Paul E. McKenney" <paulmck@kernel.org>,
        Nicholas Piggin <npiggin@gmail.com>,
        Chris Zankel <chris@zankel.net>,
        Max Filippov <jcmvbkbc@gmail.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
        "kasan-dev@googlegroups.com" <kasan-dev@googlegroups.com>,
        Rohan McLure <rmclure@linux.ibm.com>
Subject: Re: [PATCH 1/3] kcsan: Don't expect 64 bits atomic builtins from 32
 bits architectures
In-Reply-To: <662d074e-58cf-3bde-f454-e58d04803f34@csgroup.eu>
References: <cover.1683892665.git.christophe.leroy@csgroup.eu>
 <d9c6afc28d0855240171a4e0ad9ffcdb9d07fceb.1683892665.git.christophe.leroy@csgroup.eu>
 <CANpmjNMm-2Tdhp6rDzA7CYvotmmGmLUnZnA_35yLUvxHB=7s0g@mail.gmail.com>
 <662d074e-58cf-3bde-f454-e58d04803f34@csgroup.eu>
Date:   Fri, 09 Jun 2023 22:55:49 +1000
Message-ID: <877cschk16.fsf@mail.lhotse>
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Christophe Leroy <christophe.leroy@csgroup.eu> writes:
> Le 12/05/2023 =C3=A0 18:09, Marco Elver a =C3=A9crit=C2=A0:
>> On Fri, 12 May 2023 at 17:31, Christophe Leroy
>> <christophe.leroy@csgroup.eu> wrote:
>>>
>>> Activating KCSAN on a 32 bits architecture leads to the following
>>> link-time failure:
>>>
>>>      LD      .tmp_vmlinux.kallsyms1
>>>    powerpc64-linux-ld: kernel/kcsan/core.o: in function `__tsan_atomic6=
4_load':
>>>    kernel/kcsan/core.c:1273: undefined reference to `__atomic_load_8'
>>>    powerpc64-linux-ld: kernel/kcsan/core.o: in function `__tsan_atomic6=
4_store':
>>>    kernel/kcsan/core.c:1273: undefined reference to `__atomic_store_8'
...
>>>
>>> 32 bits architectures don't have 64 bits atomic builtins. Only
>>> include DEFINE_TSAN_ATOMIC_OPS(64) on 64 bits architectures.
>>>
>>> Fixes: 0f8ad5f2e934 ("kcsan: Add support for atomic builtins")
>>> Suggested-by: Marco Elver <elver@google.com>
>>> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
>>=20
>> Reviewed-by: Marco Elver <elver@google.com>
>>=20
>> Do you have your own tree to take this through with the other patches?
>
> I don't have my own tree but I guess that it can be taken by Michael for=
=20
> 6.5 via powerpc tree with acks from you and Max.
>
> Michael is that ok for you ?

Yeah I can take it.

cheers