Re: [PATCH] Fix build error in binutils 2.36

From: Michael Chang <mchang@suse.com>
To: The development of GNU GRUB <grub-devel@gnu.org>
Subject: Re: [PATCH] Fix build error in binutils 2.36
Date: Mon, 9 Aug 2021 12:37:59 +0800	[thread overview]
Message-ID: <20210809043759.GA13488@mercury> (raw)
In-Reply-To: <20210805130721.ajskggdw6ma6emzj@tomti.i.net-space.pl>

On Thu, Aug 05, 2021 at 03:07:21PM +0200, Daniel Kiper wrote:
> On Mon, Aug 02, 2021 at 05:41:15PM +0800, Michael Chang via Grub-devel wrote:
> > The xen build fails on binutils 2.36 with the following error.
> >
> > /usr/lib64/gcc/x86_64-suse-linux/10/../../../../x86_64-suse-linux/bin/ld:
> > section .note.gnu.property VMA [0000000000400158,0000000000400187]
> > overlaps section .bss VMA [000000000000f000,000000000041e1af]
> 
> Could you send us full command which is failing?

It is reproducible on xen platfrom with all defaults.

 git clone https://git.savannah.gnu.org/git/grub.git
 cd grub
 ./bootstrap
 mkdir build-xen
 cd build-xen
 ../configure --with-platform=xen
 make

> Anyway, I would consider writing our own linker script which is dropping
> .note.gnu.property if we do not need it.

Dropping it from the assembler output is a cleaner cleanup than linker
script IMHO. We also faced similar issue in the past to stripping off
this section from soruces of objcopy to produce correct binary.

 6643507ce build: Fix GRUB i386-pc build with Ubuntu gcc

To avoid falling into such trap again when manipulating on object files
we'd better use assmbler option as the fix once and for all.

> > The most significant factor is that new assembler (gnu as) generates the
> 
> Could you give us gas version which does that?

 # as --version
 GNU assembler (GNU Binutils; openSUSE Tumbleweed) 2.36.1.20210326-4
 Copyright (C) 2021 Free Software Foundation, Inc.
 This program is free software; you may redistribute it under the terms of
 the GNU General Public License version 3 or later.
 This program has absolutely no warranty.
 This assembler was configured for a target of `x86_64-suse-linux'.

> > .note.gnu.property section as default. This note section overlaps with
> > .bss because it doesn't reposition with -Wl,-Ttext,0 with which the base
> > address of .text section is set, rather the address of
> > .note.gnu.property is calculated for some reason from 0x400000 where the
> > elf executable defaults to start.
> 
> Is not it linker bug?

The binutils upstream apparently doesn't seem to consider this as a bug ...

https://sourceware.org/bugzilla/show_bug.cgi?id=27377

Thanks,
Michael

> 
> Daniel
> 
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