From: Ravi Bangoria <ravi.bangoria@linux•vnet.ibm.com>
To: Michael Ellerman <mpe@ellerman•id.au>
Cc: Anton Blanchard <anton@samba•org>,
linuxppc-dev@lists•ozlabs.org, linux-kernel@vger•kernel.org,
duwe@lst•de, ast@kernel•org, viro@zeniv•linux.org.uk,
chris@distroguy•com, oss@buserror•net,
paul.gortmaker@windriver•com, oohall@gmail•com,
aneesh.kumar@linux•vnet.ibm.com, lsorense@csclub•uwaterloo.ca,
bauerman@linux•vnet.ibm.com, paulus@samba•org,
naveen.n.rao@linux•vnet.ibm.com,
Ravi Bangoria <ravi.bangoria@linux•vnet.ibm.com>
Subject: Re: [PATCH 1/3] powerpc: Emulation support for load/store instructions on LE
Date: Thu, 3 Nov 2016 15:57:27 +0530 [thread overview]
Message-ID: <581B110F.9050805@linux.vnet.ibm.com> (raw)
In-Reply-To: <8737j8opwb.fsf@concordia.ellerman.id.au>
On Thursday 03 November 2016 03:18 PM, Michael Ellerman wrote:
> Ravi Bangoria <ravi.bangoria@linux•vnet.ibm.com> writes:
>
>> On Thursday 03 November 2016 02:34 AM, Anton Blanchard wrote:
>>> Hi Ravi,
>>>
>>>> emulate_step() uses a number of underlying kernel functions that were
>>>> initially not enabled for LE. This has been rectified since. So, fix
>>>> emulate_step() for LE for the corresponding instructions.
>>> Thanks. Should this be queued up for stable?
>> Thanks Anton. Yes, this should go in stable.
> It's fairly big for stable. Does it fix an actual bug? If so what, and
> how bad is it, what's the user impact.
Hi Michael,
Yes, kernel-space hw-breakpoint feature is broken on LE without this.
Actually, there is no specific commit that introduced this. Back
in 2010, Paul Mackerras has added emulation support for load/store
instructions for BE. hw-breakpoint was also develpoed by K.Prasad
in the same timeframe.
Kernel-space hw-breakpoint emulates causative instruction before
notifying to user. As emulate_step is never enabled for LE, kernel-
space hw-breakpoint is always broken on LE.
-Ravi
> Can you also pinpoint which commit it "fixes"?
>
> cheers
>
next prev parent reply other threads:[~2016-11-03 10:27 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-02 8:53 [PATCH 0/3] powerpc: Emulation support for load/store instructions on LE Ravi Bangoria
2016-11-02 8:53 ` [PATCH 1/3] " Ravi Bangoria
2016-11-02 21:04 ` Anton Blanchard
2016-11-03 5:41 ` Ravi Bangoria
2016-11-03 9:48 ` Michael Ellerman
2016-11-03 10:27 ` Ravi Bangoria [this message]
2016-11-04 2:07 ` Andrew Donnellan
2016-11-04 5:31 ` Ravi Bangoria
2016-11-05 19:31 ` Anton Blanchard
2016-11-06 18:59 ` Ravi Bangoria
2016-11-02 8:53 ` [PATCH 2/3] powerpc: Add encoding for couple of load/store instructions Ravi Bangoria
2016-11-02 8:53 ` [PATCH 3/3] powerpc: emulate_step test for " Ravi Bangoria
2016-11-02 10:30 ` Naveen N. Rao
2016-11-03 7:03 ` [PATCH 0/3] powerpc: Emulation support for load/store instructions on LE Naveen N. Rao
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