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From: Alex =?utf-8?Q?Benn=C3=A9e?= <alex.bennee@linaro.org>
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Date: Mon, 21 Mar 2016 09:11:14 +0000
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Subject: Re: [Qemu-devel] [FreeBSD] Host build i386 failing to build aarch64
	targets
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>, Sean Bruno <sbruno@freebsd.org>, QEMU Developers <qemu-devel@nongnu.org>


Peter Maydell <peter.maydell@linaro.org> writes:

> On 20 March 2016 at 19:20, Sean Bruno <sbruno@freebsd.org> wrote:
>> -----BEGIN PGP SIGNED MESSAGE-----
>> Hash: SHA512
>>
>> aarch64 targets are now failing to build on i386 hosts due to missing
>> __atomic_load_8() calls since this commit:
>>
>> https://github.com/qemu/qemu/commit/a0aa44b488b3601415d55041e4619aef5f3a4ba8#diff-c143d686899ae51d7b927d9c682e12fd
>>
>> I'm unsure if Linux is disabling aarch64 targets for i386 hosts or if
>> this commit works "just fine" on Linux hosts right now, as it doesn't
>> work with clang or gcc.
>
> I think it just works on most Linux 32-bit architectures because
> the compiler support can inline a suitable atomic op (there
> is one case where it doesn't, which I think is PPC32).
>
> In any case, we mustn't use atomics on types larger
> than the host pointer type, because it's not portable enough.
> Paolo or Alex, can you have a look at this?

I'll get a BSD up and running and check. What is triggering the
__atomic_load_8 though?

>
> thanks
> -- PMM


--
Alex Bennée