From: "K.Prasad" <prasad@linux.vnet.ibm.com>
To: Paul Mackerras <paulus@samba.org>
Cc: Michael Neuling <mikey@neuling.org>,
Benjamin Herrenschmidt <benh@au1.ibm.com>,
shaggy@linux.vnet.ibm.com,
Frederic Weisbecker <fweisbec@gmail.com>,
David Gibson <dwg@au1.ibm.com>,
"linuxppc-dev@ozlabs.org" <linuxppc-dev@ozlabs.org>,
Alan Stern <stern@rowland.harvard.edu>,
Roland McGrath <roland@redhat.com>
Subject: Re: [Patch 3/4] PPC64-HWBKPT: Handle concurrent alignment interrupts
Date: Fri, 28 May 2010 13:11:35 +0530 [thread overview]
Message-ID: <20100528074135.GA10511@in.ibm.com> (raw)
In-Reply-To: <20100527062044.GB4105@drongo>
On Thu, May 27, 2010 at 04:20:44PM +1000, Paul Mackerras wrote:
> On Tue, May 25, 2010 at 02:44:35PM +0530, K.Prasad wrote:
>
> > An alignment interrupt may intervene between a DSI/hw-breakpoint exception
> > and the single-step exception. Enable the alignment interrupt (through
> > modifications to emulate_single_step()) to notify the single-step exception
> > handler for proper restoration of hw-breakpoints.
> >
> > Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
> > ---
> > arch/powerpc/kernel/traps.c | 7 ++-----
> > 1 file changed, 2 insertions(+), 5 deletions(-)
> >
> > Index: linux-2.6.ppc64_test/arch/powerpc/kernel/traps.c
> > ===================================================================
> > --- linux-2.6.ppc64_test.orig/arch/powerpc/kernel/traps.c
> > +++ linux-2.6.ppc64_test/arch/powerpc/kernel/traps.c
> > @@ -602,7 +602,7 @@ void RunModeException(struct pt_regs *re
> >
> > void __kprobes single_step_exception(struct pt_regs *regs)
> > {
> > - regs->msr &= ~(MSR_SE | MSR_BE); /* Turn off 'trace' bits */
> > + clear_single_step(regs);
> >
> > if (notify_die(DIE_SSTEP, "single_step", regs, 5,
> > 5, SIGTRAP) == NOTIFY_STOP)
> > @@ -621,10 +621,7 @@ void __kprobes single_step_exception(str
> > */
> > static void emulate_single_step(struct pt_regs *regs)
> > {
> > - if (single_stepping(regs)) {
> > - clear_single_step(regs);
> > - _exception(SIGTRAP, regs, TRAP_TRACE, 0);
> > - }
> > + single_step_exception(regs);
> > }
>
> We still need the if (single_stepping(regs)) in emulate_single_step.
> We don't want to send the process a SIGTRAP every time it gets an
> alignment interrupt. :)
>
> Paul.
Agreed, and made changes to that effect in version XXII (as seen in
patch linuxppc-dev message-id: 20100528064017.GD8679@in.ibm.com).
Thanks,
K.Prasad
next prev parent reply other threads:[~2010-05-28 7:41 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20100525083055.342788418@linux.vnet.ibm.com>
2010-05-25 9:13 ` [Patch 1/4] Allow arch-specific cleanup before breakpoint unregistration K.Prasad
2010-05-25 11:39 ` Millton Miller
2010-05-26 6:51 ` K.Prasad
2010-05-26 9:54 ` David Howells
2010-05-26 15:13 ` Michael Ellerman
2010-05-26 17:17 ` K.Prasad
2010-05-26 17:23 ` Frederic Weisbecker
2010-05-26 17:31 ` K.Prasad
2010-05-26 17:35 ` Frederic Weisbecker
2010-05-26 17:28 ` K.Prasad
2010-05-25 9:14 ` [Patch 2/4] PPC64-HWBKPT: Implement hw-breakpoints for PowerPC BookIII S K.Prasad
2010-05-27 6:19 ` Paul Mackerras
2010-05-28 7:39 ` K.Prasad
2010-05-25 9:14 ` [Patch 3/4] PPC64-HWBKPT: Handle concurrent alignment interrupts K.Prasad
2010-05-27 6:20 ` Paul Mackerras
2010-05-28 7:41 ` K.Prasad [this message]
2010-05-25 9:15 ` [Patch 4/4] PPC64-HWBKPT: Enable hw-breakpoints while handling intervening signals K.Prasad
2010-05-27 6:32 ` Paul Mackerras
[not found] <20100524102614.040177456@linux.vnet.ibm.com>
2010-05-24 10:33 ` [Patch 3/4] PPC64-HWBKPT: Handle concurrent alignment interrupts K.Prasad
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