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: <20200409232728.231527-1-caij2003@gmail.com> <20201107001056.225807-1-jiancai@google.com>
 <CAMj1kXG+qb267Hig6zoO=y6_BVsKsqHikvbJ83YsBD8SBaZ1xw@mail.gmail.com>
 <CAKwvOd=pHgT3LsjYH10eXQjLPtiOKDj-8nJwjQ=NMSFLTG1xAg@mail.gmail.com> <CAMj1kXHDzj3Q-sCv1szseUC7g2bWRFeVP6WME-sMqDf+0wyU8Q@mail.gmail.com>
In-Reply-To: <CAMj1kXHDzj3Q-sCv1szseUC7g2bWRFeVP6WME-sMqDf+0wyU8Q@mail.gmail.com>
From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Tue, 10 Nov 2020 11:26:32 -0800
Message-ID: <CAKwvOdkXz5wOwKQDsi5jt21ov3xETSByAqxGLQ=7U6Gsp46zcQ@mail.gmail.com>
Subject: Re: [PATCH v2] Make iwmmxt.S support Clang's integrated assembler
To:     Ard Biesheuvel <ardb@kernel.org>
Cc:     Jian Cai <jiancai@google.com>, Manoj Gupta <manojgupta@google.com>,
        Luis Lozano <llozano@google.com>,
        clang-built-linux <clang-built-linux@googlegroups.com>,
        Russell King <linux@armlinux.org.uk>,
        Nathan Chancellor <natechancellor@gmail.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Mon, Nov 9, 2020 at 11:36 PM Ard Biesheuvel <ardb@kernel.org> wrote:
>
> BE32 != BE8

Oh? Sorry, what does BE8 stand for?  arch/arm/mm/Kconfig says:

CONFIG_CPU_ENDIAN_BE8
Support for the BE-8 (big-endian) mode on ARMv6 and ARMv7 processors.

vs:
CPU_ENDIAN_BE32
Support for the BE-32 (big-endian) mode on pre-ARMv6 processors.

So BE8 seems newer?  It looks like in my tests, enabling
CPU_BIG_ENDIAN via menuconfig enabled CPU_ENDIAN_BE8.

>
> Please use, e.g., ixp4xx_defconfig with IWMMXT and BE enabled. It
> seems like .inst does the right thing here, i.e., the assembler knows
> that it should emit BE for BE32 and LE for BE8, but it needs to be
> confirmed.

Ah and ixp4xx_defconfig selects CPU_ENDIAN_BE32.  Yep, and the
disassemblies of those match, too.
-- 
Thanks,
~Nick Desaulniers