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From: Benjamin Herrenschmidt <benh@au1.ibm.com>
To: Paul Mackerras <paulus@samba.org>
Cc: Michael Neuling <mikey@neuling.org>,
	shaggy@linux.vnet.ibm.com,
	Frederic Weisbecker <fweisbec@gmail.com>,
	David Gibson <dwg@au1.ibm.com>,
	linuxppc-dev@ozlabs.org, Alan Stern <stern@rowland.harvard.edu>,
	"K.Prasad" <prasad@linux.vnet.ibm.com>,
	Roland McGrath <roland@redhat.com>
Subject: Re: [RFC Patch 1/2] PPC64-HWBKPT: Disable interrupts for data breakpoint exceptions
Date: Tue, 30 Mar 2010 16:32:25 +1100	[thread overview]
Message-ID: <1269927145.7101.48.camel@pasglop> (raw)
In-Reply-To: <20100330052442.GB12619@drongo>

On Tue, 2010-03-30 at 16:24 +1100, Paul Mackerras wrote:
> On Tue, Mar 23, 2010 at 07:37:02PM +0530, K.Prasad wrote:
> 
> > Index: linux-2.6.ppc64_test/arch/powerpc/kernel/exceptions-64s.S
> > ===================================================================
> > --- linux-2.6.ppc64_test.orig/arch/powerpc/kernel/exceptions-64s.S
> > +++ linux-2.6.ppc64_test/arch/powerpc/kernel/exceptions-64s.S
> > @@ -735,6 +735,9 @@ _STATIC(do_hash_page)
> >  	std	r3,_DAR(r1)
> >  	std	r4,_DSISR(r1)
> >  
> > +	andis.  r0,r4,0x0040		/* Data Address Breakpoint match? */
> 
> Minor comment: why not DSISR_DABRMATCH@h instead of 0x0040?
> 
> > +	bne-    handle_dabr_fault
> > +
> >  	andis.	r0,r4,0xa450		/* weird error? */
> >  	bne-	handle_page_fault	/* if not, try to insert a HPTE */
> >  BEGIN_FTR_SECTION
> > @@ -823,6 +826,15 @@ END_FW_FTR_SECTION_IFCLR(FW_FEATURE_ISER
> >  	bl	.raw_local_irq_restore
> >  	b	11f

I would move your new test to the "weird error" case (ie, after the bne-
handle_page_fault) to avoid hitting the fast path.

Cheers,
Ben.

  reply	other threads:[~2010-03-30  5:32 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20100323140008.954823303@pr>
2010-03-23 14:07 ` [RFC Patch 1/2] PPC64-HWBKPT: Disable interrupts for data breakpoint exceptions K.Prasad
2010-03-30  5:24   ` Paul Mackerras
2010-03-30  5:32     ` Benjamin Herrenschmidt [this message]
2010-03-30 10:19       ` K.Prasad
2010-03-30 10:17     ` K.Prasad
2010-03-23 14:07 ` [RFC Patch 2/2] PPC64-HWBKPT: Implement hw-breakpoints for PPC64 K.Prasad
2010-03-26 21:11   ` Dave Kleikamp
2010-03-29 11:31     ` K.Prasad
2010-03-29 19:53       ` Dave Kleikamp
2010-03-30 10:12         ` K.Prasad

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