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From: Geoff Levand <geoffrey.levand@am•sony.com>
To: Arnd Bergmann <arnd@arndb•de>
Cc: linuxppc-dev@ozlabs•org, Paul Mackerras <paulus@samba•org>,
	Roland McGrath <roland@redhat•com>,
	Jan Kratochvil <jan.kratochvil@redhat•com>
Subject: Re: PPC upstream kernel ignored DABR bug
Date: Wed, 28 Nov 2007 14:59:36 -0800	[thread overview]
Message-ID: <474DF2D8.9010407@am.sony.com> (raw)
In-Reply-To: <200711272335.36981.arnd@arndb.de>

Arnd Bergmann wrote:
> On Monday 26 November 2007, Jan Kratochvil wrote:
>> Hi,
>> 
>> this testcase:
>>         http://people.redhat.com/jkratoch/dabr-lost.c
>> 
>> reproduces a PPC DABR kernel bug.  The variable `variable' should not get
>> modified as the thread modifying it should be caught by its DABR:
>> 
>> $ ./dabr-lost
>> TID 30914: DABR 0x10012a77 NIP 0x80f6ebb318
>> TID 30915: DABR 0x10012a77 NIP 0x80f6ebb318
>> TID 30916: DABR 0x10012a77 NIP 0x80f6ebb318
>> TID 30914: hitting the variable
>> TID 30915: hitting the variable
>> TID 30916: hitting the variable
>> variable found = 30916, caught TID = 30914
>> TID 30916: DABR 0x10012a77
>> Variable got modified by a thread which has DABR still set!
>> 
> 
> This sounds like a bug recently reported by Uli Weigand. BenH
> said he'd take a look, but it probably fell under the table.
> The problem found by Uli is that on certain processors (Cell/B.E.
> in his case), the DABRX register needs to be set in order for
> the DABR to take effect.

Just as a note, the PS3's lv1_set_dabr(), which we used for
ppc_md.set_dabr sets up both the DABRX and DABR registers.

-Geoff

  parent reply	other threads:[~2007-11-28 22:59 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-11-26 22:02 PPC upstream kernel ignored DABR bug Jan Kratochvil
2007-11-27 22:35 ` Arnd Bergmann
2007-11-28  8:59   ` Jan Kratochvil
2007-11-28 12:28     ` Arnd Bergmann
2007-11-28 12:45       ` Jan Kratochvil
2007-11-28 22:59   ` Geoff Levand [this message]
2007-11-29  0:13     ` Arnd Bergmann
2008-03-10  0:53       ` Luis Machado
2008-03-10 14:01         ` Jens Osterkamp
2008-03-10 15:13           ` Luis Machado
2008-03-10 19:19           ` Roland McGrath
2008-03-10 19:36             ` Luis Machado
2008-03-10 19:50               ` Olof Johansson
2008-03-10 19:54                 ` Roland McGrath
2008-03-10 22:06             ` Segher Boessenkool
2008-03-12 17:51           ` Luis Machado
2008-03-12 22:30             ` Jens Osterkamp
2008-03-13  1:47               ` Roland McGrath
2008-03-13 22:20                 ` Segher Boessenkool
2008-03-13 22:42                   ` Roland McGrath
2008-03-14  2:11                     ` Segher Boessenkool
2008-03-14  7:45                       ` Roland McGrath
2008-03-14  8:42                         ` Segher Boessenkool
2008-03-16 20:38                           ` Benjamin Herrenschmidt
2008-03-16 20:37                   ` Benjamin Herrenschmidt
2008-03-26 20:57                 ` Josh Boyer
2008-03-27  1:47                   ` Josh Boyer
2008-03-13 13:13               ` Luis Machado

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