Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20200918132439.1475479-1-arnd@arndb.de> <20200918132439.1475479-2-arnd@arndb.de>
 <20200919053514.GI30063@infradead.org>
In-Reply-To: <20200919053514.GI30063@infradead.org>
From:   Andy Lutomirski <luto@kernel.org>
Date:   Sat, 19 Sep 2020 09:23:22 -0700
Message-ID: <CALCETrVDqHG2chDsLWBHF39SXh6vjzE_xcEs+AWgOg5531BLuQ@mail.gmail.com>
Subject: Re: [PATCH 1/4] x86: add __X32_COND_SYSCALL() macro
To:     Christoph Hellwig <hch@infradead.org>
Cc:     Arnd Bergmann <arnd@arndb.de>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Eric Biederman <ebiederm@xmission.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        linux-arch <linux-arch@vger.kernel.org>,
        Linux-MM <linux-mm@kvack.org>, kexec@lists.infradead.org,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@alien8.de>,
        "H . Peter Anvin" <hpa@zytor.com>,
        Andy Lutomirski <luto@kernel.org>,
        Christoph Hellwig <hch@lst.de>, Brian Gerst <brgerst@gmail.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Fri, Sep 18, 2020 at 10:35 PM Christoph Hellwig <hch@infradead.org> wrote:
>
> On Fri, Sep 18, 2020 at 03:24:36PM +0200, Arnd Bergmann wrote:
> > sys_move_pages() is an optional syscall, and once we remove
> > the compat version of it in favor of the native one with an
> > in_compat_syscall() check, the x32 syscall table refers to
> > a __x32_sys_move_pages symbol that may not exist when the
> > syscall is disabled.
> >
> > Change the COND_SYSCALL() definition on x86 to also include
> > the redirection for x32.
> >
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>
> Adding the x86 maintainers and Brian Gerst.  Brian proposed another
> problem to the mess that most of the compat syscall handlers used by
> x32 here:
>
>    https://lkml.org/lkml/2020/6/16/664
>
> hpa didn't particularly like it, but with your and my pending series
> we'll soon use more native than compat syscalls for x32, so something
> will need to change..

I'm fine with either solution.