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From: Daniel Jacobowitz <drow@false.org>
To: Eli Zaretskii <eliz@gnu.org>
Cc: Wu Zhou <woodzltc@cn.ibm.com>, gdb-patches@sourceware.org
Subject: Re: [ppc-linux-nat]: set access flag for h/w watchpoint even if it is  only read or write
Date: Thu, 06 Jul 2006 21:37:00 -0000	[thread overview]
Message-ID: <20060706213659.GA985@nevyn.them.org> (raw)
In-Reply-To: <ulkr6qwkt.fsf@gnu.org>

On Thu, Jul 06, 2006 at 11:58:58PM +0300, Eli Zaretskii wrote:
> Yes, this problem is known on x86 and elsewhere.  The problem is
> extremely rare, as reading and writing to the same address in the same
> instruction is a hard-to-accomplish treat.  Wu, could you show a
> real-life example of where this matters?

I thought, though I may be misremembering, that it was actually a
different problem.  Something like this:

- We set a read watchpoint.  It does not trigger on writes.

- An instruction writes to the location.

- GDB stops, sees that it stopped at a watchpoint at the given address,
  tries to determine what sort of watchpoint it was, determines that
  the value had changed, and ignores the read watchpoint - the value
  has changed since we last checked so this "must" have been a write
  watchpoint.

Is that plausible or nonsensical?

-- 
Daniel Jacobowitz
CodeSourcery


  reply	other threads:[~2006-07-06 21:37 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-06-09 15:40 Wu Zhou
2006-06-23  0:44 ` [RFC]: h/w watchpoint (r,w,a) for ppc440 Wu Zhou
2006-07-06 13:20 ` [ppc-linux-nat]: set access flag for h/w watchpoint even if it is only read or write Daniel Jacobowitz
2006-07-06 20:59   ` Eli Zaretskii
2006-07-06 21:37     ` Daniel Jacobowitz [this message]
2006-07-07  4:35 Wu Zhou
2006-07-07 10:04 ` Eli Zaretskii
2006-07-07 13:18   ` Daniel Jacobowitz
2006-07-07 15:08     ` Eli Zaretskii
2006-07-08 19:36       ` Ulrich Weigand

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