linux-kernel - Re: [PATCH 1/2] lib/mpi: avoid assembler warning

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Message-ID: <20160227193532.GF9123@gondor.apana.org.au>
Date:	Sat, 27 Feb 2016 20:35:32 +0100
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	Arnd Bergmann <arnd@...db.de>
Cc:	linux-arm-kernel@...ts.infradead.org,
	Dmitry Kasatkin <dmitry.kasatkin@...el.com>,
	linux-crypto@...r.kernel.org, David Howells <dhowells@...hat.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] lib/mpi: avoid assembler warning

On Fri, Feb 26, 2016 at 01:46:26PM +0100, Arnd Bergmann wrote:
> A wrapper around the umull assembly instruction might reuse
> the input register as an output, which is undefined on
> some ARM machines, as pointed out by this assembler warning:
> 
>   CC      lib/mpi/generic_mpih-mul1.o
> /tmp/ccxJuxIy.s: Assembler messages:
> /tmp/ccxJuxIy.s:53: rdhi, rdlo and rm must all be different
>   CC      lib/mpi/generic_mpih-mul2.o
> /tmp/ccI0scAD.s: Assembler messages:
> /tmp/ccI0scAD.s:53: rdhi, rdlo and rm must all be different
>   CC      lib/mpi/generic_mpih-mul3.o
> /tmp/ccMvVQcp.s: Assembler messages:
> /tmp/ccMvVQcp.s:53: rdhi, rdlo and rm must all be different
> 
> This changes the constraints to force different registers to
> be used as output.
> 
> Signed-off-by: Arnd Bergmann <arnd@...db.de>

Both applied.
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt