Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1756452AbcKETcR (ORCPT <rfc822;w@1wt.eu>);
        Sat, 5 Nov 2016 15:32:17 -0400
Received: from hr2.samba.org ([144.76.82.148]:45468 "EHLO hr2.samba.org"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1755538AbcKETcQ (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Sat, 5 Nov 2016 15:32:16 -0400
Date: Sun, 6 Nov 2016 06:31:51 +1100
From: Anton Blanchard <anton@samba.org>
To: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Andrew Donnellan <andrew.donnellan@au1.ibm.com>,
        Michael Ellerman <mpe@ellerman.id.au>, chris@distroguy.com,
        aneesh.kumar@linux.vnet.ibm.com, ast@kernel.org,
        linux-kernel@vger.kernel.org, oss@buserror.net,
        paul.gortmaker@windriver.com, duwe@lst.de,
        lsorense@csclub.uwaterloo.ca, bauerman@linux.vnet.ibm.com,
        oohall@gmail.com, naveen.n.rao@linux.vnet.ibm.com,
        linuxppc-dev@lists.ozlabs.org, paulus@samba.org,
        viro@zeniv.linux.org.uk
Subject: Re: [PATCH 1/3] powerpc: Emulation support for load/store
 instructions on LE
Message-ID: <20161106063151.3ef04e9e@kryten>
In-Reply-To: <581C1D32.50108@linux.vnet.ibm.com>
References: <1478076783-2872-1-git-send-email-ravi.bangoria@linux.vnet.ibm.com>
        <1478076783-2872-2-git-send-email-ravi.bangoria@linux.vnet.ibm.com>
        <20161103080412.68240cda@kryten>
        <581ACDF2.1010409@linux.vnet.ibm.com>
        <8737j8opwb.fsf@concordia.ellerman.id.au>
        <581B110F.9050805@linux.vnet.ibm.com>
        <e993dc5c-7a90-e43b-b761-a70a79b3d1d9@au1.ibm.com>
        <581C1D32.50108@linux.vnet.ibm.com>
X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 518
Lines: 18

Hi,

> kprobe, uprobe, hw-breakpoint and xmon are the only user of
> emulate_step.
> 
> Kprobe / uprobe single-steps instruction if they can't emulate it, so
> there is no problem with them. As I mention, hw-breakpoint is broken.
> However I'm not sure about xmon, I need to check that.

I was mostly concerned that it would impact kprobes. Sounds like we are
ok there.

> So yes, there is no user-visible feature that depends on this.

Aren't hardware breakpoints exposed via perf? I'd call perf
user-visible.

Anton