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From: Robert Jarzmik <robert.jarzmik@free.fr>
To: Arnd Bergmann <arnd@kernel.org>
Cc: Daniel Mack <daniel@zonque.org>,
	Haojian Zhuang <haojian.zhuang@gmail.com>,
	Robert Jarzmik <robert.jarzmik@free.fr>,
	soc@kernel.org, Arnd Bergmann <arnd@arndb.de>,
	Russell King <linux@armlinux.org.uk>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Tom Rix <trix@redhat.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, llvm@lists.linux.dev
Subject: Re: [PATCH] ARM: pxa: fix building with clang
Date: Sat, 17 Dec 2022 21:45:41 +0100	[thread overview]
Message-ID: <m21qoxiw9t.fsf@free.fr> (raw)
In-Reply-To: <20221215160747.2173998-1-arnd@kernel.org>


Arnd Bergmann <arnd@kernel.org> writes:

> From: Arnd Bergmann <arnd@arndb.de>
>
> The integrated assembler in clang does not understand the xscale
> specific mra/mar instructions:
>
> arch/arm/mach-pxa/pxa27x.c:136:15: error: unsupported 
> architectural extension: xscale
>         asm volatile(".arch_extension xscale\n\t"
> arch/arm/mach-pxa/pxa27x.c:136:40: error: invalid instruction, 
> did you mean: mcr, mla, mrc, mrs, msr?
>         mra r2, r3, acc0
>
> Since these are coprocessor features, the same can be expressed 
> using
> mrrc/mcrr, so use that for builds with IAS.
Ok Arnd, but "mrrc" is an ARMv6 instruction if I'm not mistaken.
Yet PXA27X is an ARMv5 XScale instruction set IP.

Is that patch correct therefore, or is it just to make clang happy 
even if it's
not correct ?

Cheers.

--
Robert

WARNING: multiple messages have this Message-ID (diff)
From: Robert Jarzmik <robert.jarzmik@free.fr>
To: Arnd Bergmann <arnd@kernel.org>
Cc: Daniel Mack <daniel@zonque.org>,
	Haojian Zhuang <haojian.zhuang@gmail.com>,
	Robert Jarzmik <robert.jarzmik@free.fr>,
	soc@kernel.org, Arnd Bergmann <arnd@arndb.de>,
	Russell King <linux@armlinux.org.uk>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Tom Rix <trix@redhat.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, llvm@lists.linux.dev
Subject: Re: [PATCH] ARM: pxa: fix building with clang
Date: Sat, 17 Dec 2022 21:45:41 +0100	[thread overview]
Message-ID: <m21qoxiw9t.fsf@free.fr> (raw)
In-Reply-To: <20221215160747.2173998-1-arnd@kernel.org>


Arnd Bergmann <arnd@kernel.org> writes:

> From: Arnd Bergmann <arnd@arndb.de>
>
> The integrated assembler in clang does not understand the xscale
> specific mra/mar instructions:
>
> arch/arm/mach-pxa/pxa27x.c:136:15: error: unsupported 
> architectural extension: xscale
>         asm volatile(".arch_extension xscale\n\t"
> arch/arm/mach-pxa/pxa27x.c:136:40: error: invalid instruction, 
> did you mean: mcr, mla, mrc, mrs, msr?
>         mra r2, r3, acc0
>
> Since these are coprocessor features, the same can be expressed 
> using
> mrrc/mcrr, so use that for builds with IAS.
Ok Arnd, but "mrrc" is an ARMv6 instruction if I'm not mistaken.
Yet PXA27X is an ARMv5 XScale instruction set IP.

Is that patch correct therefore, or is it just to make clang happy 
even if it's
not correct ?

Cheers.

--
Robert

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2022-12-17 21:05 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-15 16:07 [PATCH] ARM: pxa: fix building with clang Arnd Bergmann
2022-12-15 16:07 ` Arnd Bergmann
2022-12-17 20:45 ` Robert Jarzmik [this message]
2022-12-17 20:45   ` Robert Jarzmik
2022-12-18 11:00   ` Arnd Bergmann
2022-12-18 11:00     ` Arnd Bergmann
2022-12-18 11:11     ` Robert Jarzmik
2022-12-18 11:11       ` Robert Jarzmik

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