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From: Peter Maydell <peter.maydell@linaro.org>
Date: Tue, 6 Nov 2018 11:55:01 +0000
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Subject: [Qemu-devel] aarch32 acquire/release vs mttcg
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To: QEMU Developers <qemu-devel@nongnu.org>
Cc: qemu-arm <qemu-arm@nongnu.org>, Richard Henderson <richard.henderson@linaro.org>, =?UTF-8?B?QWxleCBCZW5uw6ll?= <alex.bennee@linaro.org>

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This is out of date now we have MTTCG, isn't it?
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.

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

thanks
-- PMM