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From: Frederic Weisbecker <fweisbec@gmail.com>
To: Roland McGrath <roland@redhat.com>
Cc: Michael Stefaniuc <mstefani@redhat.com>,
	prasad@linux.vnet.ibm.com, Alan Stern <stern@rowland.harvard.edu>,
	linux-kernel@vger.kernel.org,
	Maneesh Soni <maneesh@linux.vnet.ibm.com>,
	Alexandre Julliard <julliard@winehq.org>,
	"Rafael J. Wysocki" <rjw@sisk.pl>,
	Maciej Rutecki <maciej.rutecki@gmail.com>
Subject: Re: Regression in ptrace (Wine) starting with 2.6.33-rc1
Date: Wed, 17 Feb 2010 17:03:50 +0100	[thread overview]
Message-ID: <20100217160339.GA5041@nowhere> (raw)
In-Reply-To: <20100215194724.8B5F519@magilla.sf.frob.com>

On Mon, Feb 15, 2010 at 11:47:24AM -0800, Roland McGrath wrote:
> > - The other one with 'locally'/'globally' enabled breakpoints.
> 
> There is no "local/global" enablement.  That distinction is meaningless
> given the way the kernel uses the hardware.  Which of those bits you set
> has no material effect on the watchpoint/trap behavior.  



Yeah.


 
> The only regression is in the observed bit pattern read back from dr7.
> To be 100% compatible, the hw_breakpoint ptrace-compatibility front-end
> should record the state of the useless bits to report back, so the only
> differences from the bit pattern written are whatever ones the real
> hardware would have shown from writing dr7 and reading it back.



Agreed. We have to match the previous ABI, it's a regression.

We have the NULL breakpoint address thing fixed (will push it to Ingo).
We now need to fix the local/global flag storage.

The fastest way to do so is to keep a per thread dr7 variable.
I'm looking at it and will send a fix soon.

We can think about something proper later.

Thanks.


  reply	other threads:[~2010-02-17 16:04 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-02-11 16:33 Regression in ptrace (Wine) starting with 2.6.33-rc1 Michael Stefaniuc
2010-02-11 18:22 ` Frederic Weisbecker
2010-02-11 19:49   ` Michael Stefaniuc
2010-02-12 18:15     ` Frederic Weisbecker
2010-02-13 17:33     ` K.Prasad
2010-02-13 21:29       ` Michael Stefaniuc
2010-02-14 17:15         ` Frederic Weisbecker
2010-02-14 20:13           ` Michael Stefaniuc
2010-02-14 20:41             ` Frederic Weisbecker
2010-02-14 23:05               ` Michael Stefaniuc
2010-02-15 11:57                 ` K.Prasad
2010-02-15 15:57                   ` Alexandre Julliard
2010-02-15 19:37                   ` Michael Stefaniuc
2010-02-15 19:47                     ` Roland McGrath
2010-02-17 16:03                       ` Frederic Weisbecker [this message]
2010-02-17 17:06                 ` Frederic Weisbecker
2010-02-18 17:59                 ` Regression in ptrace (Wine) starting with 2.6.33-rc1, fixes Frederic Weisbecker
2010-02-18 19:27                   ` Michael Stefaniuc
2010-02-18 19:41                     ` Alexandre Julliard
2010-02-19 17:19                       ` Frederic Weisbecker
2010-02-19 17:17                     ` Frederic Weisbecker
2010-02-18 18:00                 ` [PATCH 1/2] hw-breakpoints: Accept breakpoints on NULL address Frederic Weisbecker
2010-02-18 21:16                   ` Roland McGrath
2010-02-19 17:38                     ` Frederic Weisbecker
2010-02-19  8:51                   ` K.Prasad
2010-02-18 18:00                 ` [PATCH 2/2] hw-breakpoint: Keep track of dr7 local enable bits Frederic Weisbecker
2010-02-19  8:45                   ` K.Prasad
2010-02-19 15:34                     ` Frederic Weisbecker
2010-02-19 17:58                       ` K.Prasad
2010-02-19 18:03                         ` Frederic Weisbecker
2010-02-19  8:58                   ` K.Prasad
2010-02-19 15:49                     ` Frederic Weisbecker
2010-02-19 17:41                     ` Frederic Weisbecker
2010-02-19 18:04                       ` K.Prasad
2010-02-19 18:12                         ` [GIT PULL] hw-breakpoint regression fixes Frederic Weisbecker
2010-02-22  9:56                           ` Ingo Molnar
2010-02-19 18:12                         ` [PATCH 1/2] hw-breakpoints: Accept breakpoints on NULL address Frederic Weisbecker
2010-02-19 18:12                         ` [PATCH 2/2] hw-breakpoint: Keep track of dr7 local enable bits Frederic Weisbecker

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