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Date: Tue, 1 Sep 2015 10:54:32 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>, linux-kernel@vger.kernel.org,
        Jiri Olsa <jolsa@redhat.com>, Andy Lutomirski <luto@amacapital.net>,
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        Denys Vlasenko <dvlasenk@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Qiaowei Ren <qiaowei.ren@intel.com>, "H. Peter Anvin" <hpa@zytor.com>,
        Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 0/4] x86/insn: perf tools: Add a few new x86 instructions
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* Adrian Hunter <adrian.hunter@intel.com> wrote:

> Hi
> 
> perf tools has a copy of the x86 instruction decoder for decoding
> Intel PT. [...]

So that's the arch/x86/lib/insn.c instruction length decoder that the kernel uses 
for kprobes et al - and the two versions already forked slightly:

-#include "inat.h"
-#include "insn.h"
+#include <asm/inat.h>
+#include <asm/insn.h>

it would be nice to add a diff check to the perf build, and (non-fatally) warn 
during the build if the two versions depart from each other?

This will make sure the two versions are fully in sync in the long run as well.

( Alternatively we could perhaps also librarize it into tools/lib/, and teach the 
  kernel build to pick that one up? )

Thanks,

	Ingo