linux-kernel - Re: [PATCH] x86/tools: objdump_reformat.awk: Skip bad instructions from llvm-objdump

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Message-ID: <20240103214804.GA155391@dev-arch.thelio-3990X>
Date: Wed, 3 Jan 2024 14:48:04 -0700
From: Nathan Chancellor <nathan@...nel.org>
To: Borislav Petkov <bp@...en8.de>
Cc: tglx@...utronix.de, mingo@...hat.com, dave.hansen@...ux.intel.com,
	x86@...nel.org, mhiramat@...nel.org, linux-kernel@...r.kernel.org,
	llvm@...ts.linux.dev, patches@...ts.linux.dev
Subject: Re: [PATCH] x86/tools: objdump_reformat.awk: Skip bad instructions
 from llvm-objdump

On Wed, Jan 03, 2024 at 10:26:16PM +0100, Borislav Petkov wrote:
> On Wed, Jan 03, 2024 at 01:55:06PM -0700, Nathan Chancellor wrote:
> > On Wed, Jan 03, 2024 at 07:18:52PM +0100, Borislav Petkov wrote:
> > > On Wed, Jan 03, 2024 at 11:15:42AM -0700, Nathan Chancellor wrote:
> > > > Ping? I am still seeing this issue.
> > > 
> > > Does this need a Fixes tag and needs to go to Linus now or are you fine
> > > with 6.8-rc0?
> > 
> > This is only needed due to the recent changes from Sam and myself in
> > x86/build
> 
> I don't understand: those three commits seem unrelated to LLVM objdump
> outputting "<unknown>".
> 
> Or are you saying that you've *started* running the insn decoder selftest
> with llvm's objdump and those three commits are addressing differences
> in the output and this outstanding commit is needed too for the bad
> opcode case?

Prior to commit 5225952d74d4 ("x86/tools: Remove chkobjdump.awk"), the
insn decoder selftest would not actually run with llvm-objdump
altogether because chkobjdump.awk would fail (because it was only
written for GNU objdump). The two commits prior to 5225952d74d4 were
cleaning up differences between the output of each objdump
implementations and this change should have been a part of that work as
well, I just did not build enough configurations to see it. Hopefully
that clears things up.

Cheers,
Nathan