From: Paul Mackerras <paulus@samba.org>
To: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: linuxppc-dev@ozlabs.org, "K.Prasad" <prasad@linux.vnet.ibm.com>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Subject: Re: [RFC PATCH] powerpc: Emulate nop too
Date: Fri, 28 May 2010 12:05:56 +1000 [thread overview]
Message-ID: <20100528020556.GA10586@brick.ozlabs.ibm.com> (raw)
In-Reply-To: <20100527141203.GA20770@in.ibm.com>
On Thu, May 27, 2010 at 07:42:03PM +0530, Ananth N Mavinakayanahalli wrote:
> While we are at it, can we also add nop to the list of emulated
> instructions?
I have a patch in development that emulates most of the arithmetic,
logical and shift/rotate instructions, including ori.
While you're here (in a virtual sense at least :), could you explain
what's going on with the emulate_step() call in resume_execution() in
arch/powerpc/kernel/kprobes.c? It looks like, having decided that
emulate_step() can't handle the instruction, you single-step the
instruction out of line and then call emulate_step again on the same
instruction, in resume_execution(). Why on earth is it trying to
emulate the instruction when it has already been executed at this
point? Is there any reason why we can't just remove the emulate_step
call from resume_execution()?
Paul.
next prev parent reply other threads:[~2010-05-28 2:05 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-20 12:49 [RFC PATCH] powerpc: Emulate most load and store instructions in emulate_step() Paul Mackerras
2010-05-21 16:35 ` Milton Miller
2010-05-27 14:12 ` [RFC PATCH] powerpc: Emulate nop too Ananth N Mavinakayanahalli
2010-05-27 20:22 ` Kumar Gala
2010-05-28 3:52 ` Ananth N Mavinakayanahalli
2010-05-28 2:05 ` Paul Mackerras [this message]
2010-05-28 5:19 ` powerpc: remove resume_execution() in kprobes Ananth N Mavinakayanahalli
2010-05-28 2:28 ` [RFC PATCH] powerpc: Emulate nop too Michael Neuling
2010-05-28 4:16 ` Ananth N Mavinakayanahalli
2010-05-28 4:23 ` Michael Neuling
2010-05-28 5:54 ` Ananth N Mavinakayanahalli
2010-06-02 5:25 ` [RFC PATCH] powerpc: Emulate most load and store instructions in emulate_step() K.Prasad
2010-06-02 6:00 ` Paul Mackerras
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