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From: Peter Maydell <peter.maydell@linaro.org>
Date: Thu, 29 Jan 2015 15:17:06 +0000
Message-ID: <CAFEAcA-bfQH0WmtT+msVDZV9Fk5RaZCBCR=E2tpYSCRCdFch5Q@mail.gmail.com>
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Subject: Re: [Qemu-devel] [RFC 01/10] target-arm: protect cpu_exclusive_*.
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To: =?UTF-8?B?S09OUkFEIEZyw6lkw6lyaWM=?= <fred.konrad@greensocs.com>
Cc: mttcg@listserver.greensocs.com, "J. Kiszka" <jan.kiszka@siemens.com>, Mark Burton <mark.burton@greensocs.com>, QEMU Developers <qemu-devel@nongnu.org>, Alexander Graf <agraf@suse.de>, Paolo Bonzini <pbonzini@redhat.com>

On 16 January 2015 at 17:19,  <fred.konrad@greensocs.com> wrote:
> From: KONRAD Frederic <fred.konrad@greensocs.com>
>
> This adds a lock to avoid multiple exclusive access at the same time in case of
> TCG multithread.
>
> Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com>

All the same comments I had on this patch earlier still apply:

 * I think adding mutex handling code to all the target-*
   frontends rather than providing facilities in common
   code for them to use is the wrong approach
 * You will fail to unlock the mutex if the ldrex or strex
   takes a data abort
 * This is making no attempt to learn from or unify with
   the existing attempts at handling exclusives in linux-user.
   When we've done this work we should have a single
   mechanism for handling exclusives in a multithreaded
   host environment which is used by both softmmu and useronly
   configs

thanks
-- PMM