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From: "cedric.vincent@st.com" <cedric.vincent@st.com>
To: qemu-devel <qemu-devel@nongnu.org>,
	Peter Maydell <peter.maydell@linaro.org>
Cc: Riku Voipio <riku.voipio@iki.fi>, Aurelien Jarno <aurelien@aurel32.net>
Subject: Re: [Qemu-devel] [PATCH] sh4-linux-user: fix multi-threading regression.
Date: Fri, 30 Mar 2012 15:36:01 +0200	[thread overview]
Message-ID: <20120330133601.GA3311@gnx2503> (raw)
In-Reply-To: <1332767238-22730-1-git-send-email-cedric.vincent@st.com>

On Mon, Mar 26, 2012 at 03:07:18PM +0200, Cedric VINCENT wrote:
> This reverts commit fd4bab10 "target-sh4: optimize exceptions": the
> function cpu_restore_state() isn't expected to be called in user-mode,
> as a consequence it isn't protected from race conditions.  For
> information, syscalls are exceptions on Linux/SH4.
> 
> There were two possible fixes: either "tb_lock" is acquired/released
> around the call to cpu_restore_state() [1] or the commit that
> introduced this regression is reverted [2].

I will submit a new version of this patch where the commit fd4bab10
isn't reverted and the call to cpu_restore_state() is protected by
tb_lock instead.  Actually most of the SH4 FPU helpers may call
cpu_restore_state() indirectly, this is the same problem as with
helper_trapa().

Regards,
Cédric.

      parent reply	other threads:[~2012-03-30 13:40 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-26 13:07 [Qemu-devel] [PATCH] sh4-linux-user: fix multi-threading regression Cédric VINCENT
2012-03-26 17:23 ` Peter Maydell
2012-03-27  8:15   ` cedric.vincent
2012-04-03 12:28   ` [Qemu-devel] linux-user: threading issue in the signal handler (Was: [PATCH] sh4-linux-user: fix multi-threading) regression cedric.vincent
2012-04-03 12:48     ` Peter Maydell
2012-03-30 13:36 ` cedric.vincent [this message]

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