Re: [PATCH 0/8] s390: allow to build with llvm's integrated assembler

From: Heiko Carstens <hca@linux.ibm.com>
To: Nathan Chancellor <nathan@kernel.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>,
	Alexander Gordeev <agordeev@linux.ibm.com>,
	Jonas Paulsson <paulsson@linux.vnet.ibm.com>,
	Ulrich Weigand <ulrich.weigand@de.ibm.com>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Alexander Egorenkov <egorenar@linux.ibm.com>,
	Sven Schnelle <svens@linux.ibm.com>,
	Andreas Krebbel <krebbel@linux.ibm.com>,
	Nathan Chancellor <natechancellor@gmail.com>,
	Nick Desaulniers <ndesaulniers@google.com>,
	linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org
Subject: Re: [PATCH 0/8] s390: allow to build with llvm's integrated assembler
Date: Thu, 12 May 2022 21:03:41 +0200	[thread overview]
Message-ID: <Yn1aDRKgB9zJIk21@osiris> (raw)
In-Reply-To: <Ynwh/Uk3IyiyRzO3@dev-arch.thelio-3990X>

On Wed, May 11, 2022 at 01:52:13PM -0700, Nathan Chancellor wrote:
> Hi Heiko,
> 
> On Wed, May 11, 2022 at 02:05:24PM +0200, Heiko Carstens wrote:
> > A couple of patches which in result make it finally possible to build the
> > kernel for s390 with llvm's integrated assembler. Several configs build
> > without errors or warnings, and the kernel also works as expected.
> > 
> > Note that patch 6 ("s390/boot: workaround llvm IAS bug") reveals a
> > miscompile. This looks like a bug in the instruction definitions of the mvc
> > and clc instructions(?). I'd like to ask people to look into this, since
> > this silently generated broken code.
> 
> I think it should be pretty simple to file a bug report for this since
> it occurs in a standalone assembly file? I agree with Nick that there
> should be a bug report filed and linked to in patch 6 so that we don't
> lose track of it.

https://github.com/llvm/llvm-project/issues/55411

> I applied this series to the latest s390 for-next branch (c4fb15578802)
> and built a few in-tree and distribution configurations with clang-14
> and clang-15 then boot tested them in QEMU with a simple buildroot
> userspace. I did not see any new warnings or errors. This is awesome, I
> am excited to get this wired up in our CI!
> 
> In case it is worthwhile:
> 
> Tested-by: Nathan Chancellor <nathan@kernel.org>

Yes, it is. Thanks a lot!