From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754422AbcC3OLA (ORCPT ); Wed, 30 Mar 2016 10:11:00 -0400 Received: from mail.kernel.org ([198.145.29.136]:51368 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752955AbcC3OK7 (ORCPT ); Wed, 30 Mar 2016 10:10:59 -0400 Date: Wed, 30 Mar 2016 11:10:53 -0300 From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: Arnaldo Carvalho de Melo , linux-kernel@vger.kernel.org, Andi Kleen , Stephane Eranian , Peter Zijlstra , Clark Williams , Thomas Gleixner , Andy Lutomirski , Masami Hiramatsu , Denys Vlasenko , Zi Shen Lim Subject: Re: [PATCH 10/11] perf tools: Add probing for udev86 library Message-ID: <20160330141053.GB3420@kernel.org> References: <1459294889-12148-1-git-send-email-acme@kernel.org> <1459294889-12148-11-git-send-email-acme@kernel.org> <20160330104326.GB4681@gmail.com> <20160330133625.GB2793@redhat.com> <20160330135246.GA29990@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160330135246.GA29990@gmail.com> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Wed, Mar 30, 2016 at 03:52:46PM +0200, Ingo Molnar escreveu: > * Arnaldo Carvalho de Melo wrote: > > Em Wed, Mar 30, 2016 at 12:43:27PM +0200, Ingo Molnar escreveu: > > > > From: Andi Kleen > > > > Add autoprobing for the udev86 disassembler library. > > > So the typo in the title is confusing, what is 'udev86'? > > > Also, this library does not seem to be available on stock Ubuntu. We should not be > > > adding library dependencies that cannot be resolved on major distros: > > Ok, I'll remove, I thought it would be ok because I fired up: > > # dnf install udis86-devel > > On fedora and it installed straight away, but after I started trying to > > update my docker images I couldn't find it on debian > > experimental/unstable: > > Nor even in OpenSuSE: > > Or even Mageia: > Yeah, so udis86 also seems to be a pretty old, relatively stale library with no > support for new instructions AFAICS. > So I'd rather encourage librarizing one of the x86 instruction decoders in > arch/x86/, and adding pretty-printing functionality to it. The code can already That was my first reaction too, but then, having some interesting results right now, I thought, would either push development on the udis86 code or show that it is not going anywhere and thus we better try doing what you're suggesting, which was my initial suggestion to Andi. > see instruction boundaries, which is the hardest part. > That would also be better supported on non-x86 architectures in the long run: > triton:~/tip> find arch/ -name insn.c | xargs ls -l > -rw-rw-r-- 1 mingo mingo 30244 Mar 29 11:24 arch/arm64/kernel/insn.c > -rw-rw-r-- 1 mingo mingo 1347 Dec 8 06:27 arch/arm/kernel/insn.c > -rw-rw-r-- 1 mingo mingo 15123 Mar 30 12:31 arch/x86/lib/insn.c > Such an in-kernel-repo library could also be used by live kernel debuggers such as > kgdb/kdb, oops/crash-time disassembly printout, etc. > ... so how about that direction instead? I'd much rather see it in that direction too, for the time being, I'm removing the udis86 patches from acme/perf/core, - Arnaldo