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From: Ralf Baechle <ralf@linux-mips.org>
To: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org, Chris Dearman <chris.dearman@imgtec.com>
Subject: Re: [PATCH] mips: fix execution hazard during watchpoint register probe
Date: Tue, 18 Jun 2013 16:42:53 +0200	[thread overview]
Message-ID: <20130618144253.GA19573@linux-mips.org> (raw)
In-Reply-To: <1371314080-48198-1-git-send-email-paul.burton@imgtec.com>

On Sat, Jun 15, 2013 at 05:34:40PM +0100, Paul Burton wrote:

> Writing a value to a WatchLo* register creates an execution hazard, so
> if its value is then read before that hazard is cleared then said value
> may be invalid. The mips_probe_watch_registers function must therefore
> clear the execution hazard between setting the match bits in a WatchLo*
> register & reading the register back in order to check which are set.
> 
> This fixes intermittent incorrect watchpoint register probing on some
> MIPS cores such as interAptiv & proAptiv.

Obviously correct.  Did somebody once have a tool to test for this kind
of back-to-back cp0 issues?

  Ralf

      parent reply	other threads:[~2013-06-18 14:42 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-06-15 16:34 [PATCH] mips: fix execution hazard during watchpoint register probe Paul Burton
2013-06-15 16:34 ` Paul Burton
2013-06-18 14:42 ` Ralf Baechle [this message]

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