From: Herbert Xu <herbert@gondor.apana.org.au>
To: Nathan Chancellor <natechancellor@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>,
James Hogan <jhogan@kernel.org>,
linux-mips@vger.kernel.org, linux-crypto@vger.kernel.org,
linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com,
Nick Desaulniers <ndesaulniers@google.com>
Subject: Re: [PATCH v2] lib/mpi: Eliminate unused umul_ppmm definitions for MIPS
Date: Thu, 22 Aug 2019 15:55:37 +1000 [thread overview]
Message-ID: <20190822055537.GC3860@gondor.apana.org.au> (raw)
In-Reply-To: <20190812193256.55103-1-natechancellor@gmail.com>
On Mon, Aug 12, 2019 at 12:32:57PM -0700, Nathan Chancellor wrote:
> Clang errors out when building this macro:
>
> lib/mpi/generic_mpih-mul1.c:37:24: error: invalid use of a cast in a
> inline asm context requiring an l-value: remove the cast or build with
> -fheinous-gnu-extensions
> umul_ppmm(prod_high, prod_low, s1_ptr[j], s2_limb);
> ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> lib/mpi/longlong.h:652:20: note: expanded from macro 'umul_ppmm'
> : "=l" ((USItype)(w0)), \
> ~~~~~~~~~~^~~
> lib/mpi/generic_mpih-mul1.c:37:3: error: invalid output constraint '=h'
> in asm
> umul_ppmm(prod_high, prod_low, s1_ptr[j], s2_limb);
> ^
> lib/mpi/longlong.h:653:7: note: expanded from macro 'umul_ppmm'
> "=h" ((USItype)(w1)) \
> ^
> 2 errors generated.
>
> The C version that is used for GCC 4.4 and up works well with clang;
> however, it is not currently being used because Clang masks itself
> as GCC 4.2.1 for compatibility reasons. As Nick points out, we require
> GCC 4.6 and newer in the kernel so we can eliminate all of the
> versioning checks and just use the C version of umul_ppmm for all
> supported compilers.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/605
> Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
>
> This supersedes the following two patches:
>
> https://lore.kernel.org/lkml/20190812033120.43013-4-natechancellor@gmail.com/
>
> https://lore.kernel.org/lkml/20190812033120.43013-5-natechancellor@gmail.com/
>
> I labelled this as a v2 so those don't get applied.
>
> lib/mpi/longlong.h | 36 +-----------------------------------
> 1 file changed, 1 insertion(+), 35 deletions(-)
Patch applied. Thanks.
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
prev parent reply other threads:[~2019-08-22 5:55 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-12 19:32 [PATCH v2] lib/mpi: Eliminate unused umul_ppmm definitions for MIPS Nathan Chancellor
2019-08-12 19:37 ` Nick Desaulniers
2019-08-22 5:55 ` Herbert Xu [this message]
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