Re: [PATCH RFC] x86: remove toolchain check for X32 ABI capability

From: Masahiro Yamada <masahiroy@kernel.org>
To: Nathan Chancellor <nathan@kernel.org>
Cc: X86 ML <x86@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
	Borislav Petkov <bp@alien8.de>, "H . Peter Anvin" <hpa@zytor.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Fangrui Song <maskray@google.com>,
	clang-built-linux <clang-built-linux@googlegroups.com>,
	"H . J . Lu" <hjl.tools@gmail.com>,
	Andy Lutomirski <luto@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
	Brian Gerst <brgerst@gmail.com>,
	"Chang S. Bae" <chang.seok.bae@intel.com>,
	Chao Yu <chao@kernel.org>, "Darrick J. Wong" <djwong@kernel.org>,
	Dmitry Safonov <0x7f454c46@gmail.com>,
	Dominik Brodowski <linux@dominikbrodowski.net>,
	Gabriel Krisman Bertazi <krisman@collabora.com>,
	Ingo Molnar <mingo@redhat.com>, Jaroslav Kysela <perex@perex.cz>,
	Jason Gunthorpe <jgg@ziepe.ca>,
	Jethro Beekman <jethro@fortanix.com>,
	Kees Cook <keescook@chromium.org>,
	Miklos Szeredi <miklos@szeredi.hu>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Sasha Levin <sashal@kernel.org>,
	Sean Christopherson <seanjc@google.com>,
	Takashi Iwai <tiwai@suse.com>,
	ALSA Development Mailing List <alsa-devel@alsa-project.org>,
	Linux FS-devel Mailing List <linux-fsdevel@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-xfs <linux-xfs@vger.kernel.org>
Subject: Re: [PATCH RFC] x86: remove toolchain check for X32 ABI capability
Date: Mon, 7 Jun 2021 16:39:16 +0900	[thread overview]
Message-ID: <CAK7LNASY_+_38XEMLZAf7txr4EdukkcFL8pnGGe2XyhQ9F4oDQ@mail.gmail.com> (raw)
In-Reply-To: <20210228064936.zixrhxlthyy6fmid@24bbad8f3778>

On Sun, Feb 28, 2021 at 3:49 PM Nathan Chancellor <nathan@kernel.org> wrote:
>
> On Sun, Feb 28, 2021 at 12:15:16PM +0900, Masahiro Yamada wrote:
> > On Sun, Feb 28, 2021 at 3:41 AM Masahiro Yamada <masahiroy@kernel.org> wrote:
> > >
> > > This commit reverts 0bf6276392e9 ("x32: Warn and disable rather than
> > > error if binutils too old").
> > >
> > > The help text in arch/x86/Kconfig says enabling the X32 ABI support
> > > needs binutils 2.22 or later. This is met because the minimal binutils
> > > version is 2.23 according to Documentation/process/changes.rst.
> > >
> > > I would not say I am not familiar with toolchain configuration, but
> >
> > I mean:
> > I would not say I am familiar ...
> > That is why I added RFC.
> >
> > I appreciate comments from people who are familiar
> > with toolchains (binutils, llvm).
> >
> > If this change is not safe,
> > we can move this check to Kconfig at least.
>
> Hi Masahiro,
>
> As Fangrui pointed out, there are two outstanding issues with x32 with
> LLVM=1, both seemingly related to LLVM=1.

Is this still a problem for Clang built Linux?

> https://github.com/ClangBuiltLinux/linux/issues/514

I am not tracking the status.
What was the conclusion?

> https://github.com/ClangBuiltLinux/linux/issues/1141

This got marked "unreproducible"

>
> Additionally, there appears to be one from Arnd as well but that one has
> received no triage yet.
>
> https://github.com/ClangBuiltLinux/linux/issues/1205

Same as well.

>
> I intend to test this patch as well as a few others at some point in the
> coming week although I am having to play sysadmin due to moving servers
> so I might not be able to get to it until later in the week.
>
> Cheers,
> Nathan
>

-- 
Best Regards
Masahiro Yamada