linux-kernel - Re: [PATCH 7/7] Kbuild: lto: pass -m32/-m64 to to LDFINAL

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 2 Feb 2018 21:18:57 +0100
From:   Arnd Bergmann <arnd@...db.de>
To:     Nicolas Pitre <nicolas.pitre@...aro.org>
Cc:     Andi Kleen <ak@...ux.intel.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>
Subject: Re: [PATCH 7/7] Kbuild: lto: pass -m32/-m64 to to LDFINAL

On Fri, Feb 2, 2018 at 7:41 PM, Nicolas Pitre <nicolas.pitre@...aro.org> wrote:
> On Fri, 2 Feb 2018, Arnd Bergmann wrote:
>
>> Building randconfig kernels with a biarch compiler fails with LTO
>> when the final link uses a different target architecture compared
>> to the earlier compilation stages.
>>
>> Setting -m32 or -m64 in ${LDFINAL} solves this problem, though my
>> feeling is that there is a better way to do this. There might also
>> be other from KBUILD_CFLAGS that we may need in LDFINAL.
>
> On ARM I had the same problem as it requires explicit arch flags. I
> therefore used this patch:

> -exec $CC $ARGS
> +case "${KBUILD_VERBOSE}" in
> +*1*)
> +       set -x
> +       ;;
> +esac
> +
> +exec $CC $KBUILD_CFLAGS $ARGS

Ah, right, that's much simpler. I'll put that in my test tree now and
will see if it works on x86.

Do you have a git tree with other changes for LTO on ARM? I'd
like to try that as well.

       Arnd