linux-kernel - RE: [PATCH 1/2] compiler.h: Avoid using inline asm operand modifiers

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Date:   Wed, 10 Nov 2021 10:39:35 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Vasily Gorbik' <gor@...ux.ibm.com>,
        Josh Poimboeuf <jpoimboe@...hat.com>
CC:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>, Borislav Petkov <bp@...e.de>,
        Miroslav Benes <mbenes@...e.cz>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 1/2] compiler.h: Avoid using inline asm operand modifiers

From: Vasily Gorbik
> Sent: 08 November 2021 15:41
> 
> On Fri, Nov 05, 2021 at 09:54:18AM -0700, Josh Poimboeuf wrote:
> > On Wed, May 19, 2021 at 03:03:08PM +0200, Vasily Gorbik wrote:
> > > The expansion of annotate_reachable/annotate_unreachable on s390 will
> > > result in a compiler error if the __COUNTER__ value is high enough.
...
> > I wonder if we could go back to the original approach of providing
> > __COUNTER__ as an input to the asm, but then mask it to < 128.
...
> >   * The __COUNTER__ based labels are a hack to make each instance of the macros
> >   * unique, to convince GCC not to merge duplicate inline asm statements.

I've used asm comments get the same effect.
Annoyingly there isn't a standard comment delimiter.

I think you can just use a .equ (or .set) directive (to assign a value)
rather than putting a value into a 'to be discarded' section.

	David

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