From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <mpe@ellerman.id.au>
Received: from ozlabs.org (ozlabs.org [103.22.144.67])
 (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by lists.ozlabs.org (Postfix) with ESMTPS id 714FE1A000B
 for <linuxppc-dev@lists.ozlabs.org>; Wed,  2 Jul 2014 14:41:22 +1000 (EST)
Message-ID: <1404276081.7254.1.camel@concordia>
Subject: Re: Re: [PATCH v4] [BUGFIX] kprobes: Fix "Failed to find blacklist"
 error on ia64 and ppc64
From: Michael Ellerman <mpe@ellerman.id.au>
To: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Date: Wed, 02 Jul 2014 14:41:21 +1000
In-Reply-To: <53B21B0E.8010707@hitachi.com>
References: <20140620022307.23075.55858.stgit@kbuild-fedora.novalocal>
 <53B0D61B.9010104@hitachi.com> <1404128176.7888.1.camel@concordia>
 <53B21B0E.8010707@hitachi.com>
Content-Type: text/plain; charset="UTF-8"
Mime-Version: 1.0
Cc: Jeremy Fitzhardinge <jeremy@goop.org>, linux-ia64@vger.kernel.org,
 sparse@chrisli.org, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
 Paul Mackerras <paulus@samba.org>, "H.
 Peter Anvin" <hpa@zytor.com>, akataria@vmware.com,
 linux-tip-commits@vger.kernel.org, anil.s.keshavamurthy@intel.com,
 Ingo Molnar <mingo@kernel.org>, "Suzuki K. Poulose" <suzuki@in.ibm.com>,
 Fenghua Yu <fenghua.yu@intel.com>, Arnd Bergmann <arnd@arndb.de>,
 Rusty Russell <rusty@rustcorp.com.au>, Chris Wright <chrisw@sous-sol.org>,
 yrl.pp-manager.tt@hitachi.com, Thomas Gleixner <tglx@linutronix.de>,
 Tony Luck <tony.luck@intel.com>, Kevin Hao <haokexin@gmail.com>,
 Linus Torvalds <torvalds@linux-foundation.org>, rdunlap@infradead.org,
 Tony Luck <tony.luck@gmail.com>, dl9pf@gmx.de,
 Andrew Morton <akpm@linux-foundation.org>, linuxppc-dev@lists.ozlabs.org,
 "David S. Miller" <davem@davemloft.net>
List-Id: Linux on PowerPC Developers Mail List <linuxppc-dev.lists.ozlabs.org>
List-Unsubscribe: <https://lists.ozlabs.org/options/linuxppc-dev>,
 <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=unsubscribe>
List-Archive: <http://lists.ozlabs.org/pipermail/linuxppc-dev/>
List-Post: <mailto:linuxppc-dev@lists.ozlabs.org>
List-Help: <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=help>
List-Subscribe: <https://lists.ozlabs.org/listinfo/linuxppc-dev>,
 <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=subscribe>

On Tue, 2014-07-01 at 11:21 +0900, Masami Hiramatsu wrote:
> (2014/06/30 20:36), Michael Ellerman wrote:
> > On Mon, 2014-06-30 at 12:14 +0900, Masami Hiramatsu wrote:
> >> Ping? :)
> > 
> > Yeah sorry. I started looking at this and got dragged into another mess.
> > 
> > You seem to have duplicated the functionality of arch_deref_entry_point(),
> > which was also added for kprobes, and for the same reason - ie. because some
> > arches have strange function pointers. Is there some reason you can't use it?
> 
> Ah, right! Hmm, it seems some more work to update it. but basically, we can do.
> BTW, is there any other users who need to access the actual function entry (for
> kallsyms case)?

Not that I'm aware of. We have had function descriptors on 64-bit powerpc for
ever, so in theory by now we should have already found any cases where we need
that sort of wrapper.

cheers