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

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Message-ID: <20240103215119.GB155391@dev-arch.thelio-3990X>
Date: Wed, 3 Jan 2024 14:51:19 -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 02:48:09PM -0700, Nathan Chancellor wrote:
> 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.

For the record, this explanation really should have been in the commit
message of 5225952d74d4 but I guess I was not thinking at the time.

Cheers,
Nathan