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From:   YiFei Zhu <zhuyifei1999@gmail.com>
Date:   Wed, 4 Nov 2020 05:48:21 -0600
Message-ID: <CABqSeAQ+3sjLXH7GVt_tZrFT_e0nNMm8QgT+FBNQYSOc8viM=A@mail.gmail.com>
Subject: Re: [PATCH seccomp 3/8] powerpc: Enable seccomp architecture tracking
To:     Michael Ellerman <mpe@ellerman.id.au>
Cc:     Linux Containers <containers@lists.linux-foundation.org>,
        linux-sh@vger.kernel.org, Tobin Feldman-Fitzthum <tobin@ibm.com>,
        Hubertus Franke <frankeh@us.ibm.com>,
        Jack Chen <jianyan2@illinois.edu>,
        linux-riscv@lists.infradead.org,
        Andrea Arcangeli <aarcange@redhat.com>,
        linux-s390@vger.kernel.org, YiFei Zhu <yifeifz2@illinois.edu>,
        linux-csky@vger.kernel.org, Tianyin Xu <tyxu@illinois.edu>,
        linux-xtensa@linux-xtensa.org, Kees Cook <keescook@chromium.org>,
        Jann Horn <jannh@google.com>,
        Valentin Rothberg <vrothber@redhat.com>,
        Aleksa Sarai <cyphar@cyphar.com>,
        Josep Torrellas <torrella@illinois.edu>,
        Will Drewry <wad@chromium.org>, linux-parisc@vger.kernel.org,
        kernel list <linux-kernel@vger.kernel.org>,
        Andy Lutomirski <luto@amacapital.net>,
        Dimitrios Skarlatos <dskarlat@cs.cmu.edu>,
        David Laight <David.Laight@aculab.com>,
        Giuseppe Scrivano <gscrivan@redhat.com>,
        linuxppc-dev@lists.ozlabs.org, Tycho Andersen <tycho@tycho.pizza>
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On Wed, Nov 4, 2020 at 4:22 AM Michael Ellerman <mpe@ellerman.id.au> wrote:
> > +#ifdef __LITTLE_ENDIAN__
>
> As Kees mentioned this should (must?!) match the configured endian.
>
> But I think it would still be better to use the CONFIG symbol, which is
> CONFIG_CPU_LITTLE_ENDIAN.

My attempt here is to be consistent with asm/syscall.h
syscall_get_arch [1]. Would it make sense to change that to
CONFIG_CPU_LITTLE_ENDIAN then?

[1] https://elixir.bootlin.com/linux/latest/source/arch/powerpc/include/asm/syscall.h#L116

> > +# define SECCOMP_ARCH_NATIVE         (AUDIT_ARCH_PPC64 | __SECCOMP_ARCH_LE)
>
> You use __SECCOMP_ARCH_LE there, but previously you only defined
> __SECCOMP_ARCH_LE_BIT.
>
> Is there some magic somewhere that defines __SECCOMP_ARCH_LE based on
> __SECCOMP_ARCH_LE_BIT ?

Oops, my bad here.

> > +# define SECCOMP_ARCH_NATIVE_NR              NR_syscalls
> > +# define SECCOMP_ARCH_NATIVE_NAME    "ppc64"
>
> What's the name used for?

This is used in the last patch in this series to report in procfs the
name of each architecture tracked by the bitmap cache.

> Usually we use "ppc64" for 64-bit big endian and "ppc64le" for 64-bit
> little endian.
>
> And usually we use "ppc" for 32-bit.

Ok.

YiFei Zhu