linux-kernel - Re: [PATCH] Kconfig: Explicitly disable asm goto w/ outputs on gcc-11 (and earlier)

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Date: Wed, 14 Feb 2024 10:43:50 -0800
From: Linus Torvalds <torvalds@...ux-foundation.org>
To: Uros Bizjak <ubizjak@...il.com>
Cc: Nick Desaulniers <ndesaulniers@...gle.com>, Jakub Jelinek <jakub@...hat.com>, 
	Sean Christopherson <seanjc@...gle.com>, "Andrew Pinski (QUIC)" <quic_apinski@...cinc.com>, 
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, Masahiro Yamada <masahiroy@...nel.org>, 
	Peter Zijlstra <peterz@...radead.org>, "kvm@...r.kernel.org" <kvm@...r.kernel.org>
Subject: Re: [PATCH] Kconfig: Explicitly disable asm goto w/ outputs on gcc-11
 (and earlier)

On Sun, 11 Feb 2024 at 03:12, Uros Bizjak <ubizjak@...il.com> wrote:
>
> So, I'd suggest at least limit the workaround to known-bad compilers.

Based on the current state of

    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113921

I would suggest this attached kernel patch, which makes the manual
"volatile" the default case (since it should make no difference except
for the known gcc issue), and limits the extra empty asm serialization
to gcc versions older than 12.1.0.

But Jakub is clearly currently trying to figure out exactly what was
going wrong, so things may change. Maybe the commit he bisected to
happened to just accidentally hide the real issue.

                Linus

View attachment "patch.diff" of type "text/x-patch" (1949 bytes)