linux-kernel - Re: [lpieralisi-pci:pci/rcar 2/2] drivers/pci/controller/pcie-rcar-host.c:139:3: error: instruction requires: data-barriers

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] [day] [month] [year] [list]

Message-ID: <CAK8P3a0pv3WGCAywSR8QcaLBHsu4EPz+KkN8Ybbge4CwA3rHBg@mail.gmail.com>
Date:   Thu, 10 Mar 2022 08:39:51 +0100
From:   Arnd Bergmann <arnd@...db.de>
To:     Nathan Chancellor <nathan@...nel.org>
Cc:     Bjorn Helgaas <helgaas@...nel.org>,
        kernel test robot <lkp@...el.com>,
        Marek Vasut <marek.vasut+renesas@...il.com>,
        llvm@...ts.linux.dev, kbuild-all@...ts.01.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Arnd Bergmann <arnd@...db.de>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Ard Biesheuvel <ardb@...nel.org>
Subject: Re: [lpieralisi-pci:pci/rcar 2/2] drivers/pci/controller/pcie-rcar-host.c:139:3:
 error: instruction requires: data-barriers

On Thu, Mar 10, 2022 at 1:18 AM Nathan Chancellor <nathan@...nel.org> wrote:

> > To avoid this error, for now I have cherry-picked de6b5097f58b to a
> > local pci/host/rcar branch and dropped 9775965dbae5.
>
> FWIW, this is not clang specific, the same configuration blows up with
> GCC 11.2.0 as well:
>
> $ make -skj"$(nproc)" \
>        ARCH=arm \
>        CROSS_COMPILE=arm-linux-gnueabi- \
>        olddefconfig drivers/pci/controller/pcie-rcar-host.o
> /tmp/ccz8ybtm.s: Assembler messages:
> /tmp/ccz8ybtm.s:742: Error: selected processor does not support `isb' in ARM mode
> /tmp/ccz8ybtm.s:812: Error: selected processor does not support `isb' in ARM mode
> make[4]: *** [scripts/Makefile.build:288: drivers/pci/controller/pcie-rcar-host.o] Error 1
>
> $ rg CONFIG_CPU_32 .config
> 289:CONFIG_CPU_32v4=y
>
> It does not look like isb can be used with this configuration, at least
> if I understand arch/arm/include/asm/barrier.h correctly.

My first thought was to amend the #ifdef to

#if IS_ENABLED(CONFIG_ARM) && IS_ENABLED(CONFIG_ARCH_RENESAS)

However, this is still broken because you can build a kernel that
enables the Renesas ARMv7 platform along with early ARMv6 (omap2 and
imx3) that do not support "isb" either.

What I think we want to do here instead is to add a ".arch armv7-a" in the
inline assembly.

        Arnd