From: Roland McGrath <roland@redhat.com>
To: ananth@in.ibm.com
Cc: fche@redhat.com (Frank Ch. Eigler),
Prerna Saxena <prerna@linux.vnet.ibm.com>,
systemtap@sourceware.org
Subject: Re: [RFC] Systemtap translator support for hardware breakpoints on
Date: Fri, 08 Jan 2010 10:24:00 -0000 [thread overview]
Message-ID: <20100108102402.9C10D105E4@magilla.sf.frob.com> (raw)
In-Reply-To: Ananth N Mavinakayanahalli's message of Friday, 8 January 2010 10:31:32 +0530 <20100108050127.GC4098@in.ibm.com>
> On x86, you imply something akin to using one debug register monitoring
> "write" and the other monitoring "rw" for the same address, right?
Right.
> We did try this sometime back. The event does trigger an (one) exception
> and the only way to distinguish whether a 'read' happened is to look
> at the debug status register (DR6) and see if one or both bits are set,
> and take appropriate action.
Right, that's what I meant.
> Maybe, a better way to do it is to hide this complexity by stap taking
> care of using 2 DRs underneath --
That's exactly what I was suggesting.
> but there is no ironclad gurantee that
> 2 free debug registers are available for stap's use at all times.
Indeed, nor that there is one.
Thanks,
Roland
next prev parent reply other threads:[~2010-01-08 10:24 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-07 8:35 Prerna Saxena
2010-01-07 18:01 ` Frank Ch. Eigler
2010-01-07 21:57 ` Roland McGrath
2010-01-07 22:39 ` Roland McGrath
2010-01-07 22:45 ` Frank Ch. Eigler
2010-01-08 5:01 ` Ananth N Mavinakayanahalli
2010-01-08 10:24 ` Roland McGrath [this message]
2010-01-09 1:29 ` K.Prasad
2010-01-09 1:56 ` Roland McGrath
2010-01-08 14:35 ` [RFC] Systemtap translator support for hw breakpoints on x86 Prerna Saxena
2010-01-08 15:21 ` Frank Ch. Eigler
2010-01-09 1:41 ` K.Prasad
2010-01-25 19:00 ` [RFC V2] Systemtap translator support for kernel hardware breakpoints Prerna Saxena
2010-01-26 21:16 ` Frank Ch. Eigler
2010-01-27 15:55 ` Prerna Saxena
2010-01-27 17:12 ` Frank Ch. Eigler
2010-01-28 9:59 ` Prerna Saxena
2010-01-29 9:15 ` Prerna Saxena
2010-01-07 23:15 ` [RFC] Systemtap translator support for hardware breakpoints on Roland McGrath
2010-01-08 1:03 ` Frank Ch. Eigler
2010-01-08 1:28 ` Roland McGrath
2010-01-08 1:19 ` Roland McGrath
2010-01-08 1:53 ` Roland McGrath
2010-01-08 16:08 ` Prerna Saxena
2010-01-08 18:52 ` Roland McGrath
2010-01-09 0:54 ` K.Prasad
2010-01-09 1:07 ` Roland McGrath
2010-01-09 1:11 ` K.Prasad
2010-01-09 1:45 ` Roland McGrath
2010-01-09 2:46 ` K.Prasad
2010-01-10 21:37 ` Roland McGrath
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