Re: [PATCH] Documentation/changes: Raise minimum supported binutils version to 2.23

From: Masahiro Yamada <masahiroy@kernel.org>
To: Kees Cook <keescook@chromium.org>, Borislav Petkov <bp@alien8.de>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>,
	Arvind Sankar <nivedita@alum.mit.edu>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, X86 ML <x86@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Thomas Lendacky <Thomas.Lendacky@amd.com>,
	Mauro Rossi <issor.oruam@gmail.com>, Michael Matz <matz@suse.de>
Subject: Re: [PATCH] Documentation/changes: Raise minimum supported binutils version to 2.23
Date: Tue, 24 Mar 2020 18:02:02 +0900	[thread overview]
Message-ID: <CAK7LNARMBkc666kZ9jOG9sSThzA69JvKi++WZXMtCP9ddyqcBw@mail.gmail.com> (raw)
In-Reply-To: <202003231350.7D35351@keescook>

Hi.

On Tue, Mar 24, 2020 at 5:51 AM Kees Cook <keescook@chromium.org> wrote:
>
> On Mon, Mar 23, 2020 at 02:44:54PM -0600, Jason A. Donenfeld wrote:
> > On Mon, Mar 16, 2020 at 05:02:59PM +0100, Borislav Petkov wrote:
> > > Long overdue patch, see below.
> > >
> > > Plan is to queue it after 5.7-rc1.
> > >
> > > ---
> > > From: Borislav Petkov <bp@suse.de>
> > > Date: Mon, 16 Mar 2020 16:28:36 +0100
> > > Subject: [PATCH] Documentation/changes: Raise minimum supported binutilsa version to 2.23
> > >
> > > The currently minimum-supported binutils version 2.21 has the problem of
> > > promoting symbols which are defined outside of a section into absolute.
> > > According to Arvind:
> > >
> > >   binutils-2.21 and -2.22. An x86-64 defconfig will fail with
> > >           Invalid absolute R_X86_64_32S relocation: _etext
> > >   and after fixing that one, with
> > >           Invalid absolute R_X86_64_32S relocation: __end_of_kernel_reserve
> > >
> > > Those two versions of binutils have a bug when it comes to handling
> > > symbols defined outside of a section and binutils 2.23 has the proper
> > > fix, see: https://sourceware.org/legacy-ml/binutils/2012-06/msg00155.html
> > >
> > > Therefore, up to the fixed version directly, skipping the broken ones.
> > >
> > > Currently shipping distros already have the fixed binutils version so
> > > there should be no breakage resulting from this.
> > >
> > > For more details about the whole thing, see the thread in Link.
> >
> > That sounds very good to me. Then we'll be able to use ADX instructions
> > without ifdefs.
> >
> > Acked-by: Jason A. Donenfeld <Jason@zx2c4.com>
>
> Can you send these now and we can land in 5.7 with the doc change?
>
> -Kees

Kees,

I folded this patch into the following series (16 patches):
https://lore.kernel.org/patchwork/project/lkml/list/?series=435391

This patch (14/16) is a prerequisite for 15/16.

Borislav,

When I forwarded this patch, I fixed up one more line.
(changes.rst duplicates the same information...)

Please see this. I hope this should be OK.
https://lore.kernel.org/patchwork/patch/1214519/

> --
> Kees Cook

--
Best Regards
Masahiro Yamada