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From: "Alex Bennée" <alex.bennee@linaro.org>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: QEMU Developers <qemu-devel@nongnu.org>,
	qemu-arm <qemu-arm@nongnu.org>,
	Richard Henderson <richard.henderson@linaro.org>
Subject: Re: [Qemu-devel] aarch32 acquire/release vs mttcg
Date: Tue, 06 Nov 2018 14:23:25 +0000	[thread overview]
Message-ID: <87o9b2e142.fsf@linaro.org> (raw)
In-Reply-To: <CAFEAcA9J__5kPwE7P4SwHYmOp=V0fzoGq5BzBKeStytb6W3=ug@mail.gmail.com>


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

> Looking through code I noticed that in target/arm/translate.c there
> is the following comment in the decode for the load-acquire/store-release
> instructions:
>
>       /* Since the emulation does not have barriers,
>          the acquire/release semantics need no special
>          handling */
>
> This is out of date now we have MTTCG, isn't it?

Yes

> The equivalent code in translate-a64.c has some calls to tcg_gen_mb()
> to emit barriers...presumably we need to fix the a32 code to do
> the same.

Sounds right. Are they the same semantics as their bigger 64 bit
cousins?

>
> (We haven't noticed this because I think in practice nobody
> much is compiling Armv8-specific AArch32 code.)
>
> thanks
> -- PMM


--
Alex Bennée

      reply	other threads:[~2018-11-06 14:23 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-06 11:55 [Qemu-devel] aarch32 acquire/release vs mttcg Peter Maydell
2018-11-06 14:23 ` Alex Bennée [this message]

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