The ARM version of the accelerated XOR routines are simply the 8-way C
routines passed through the auto-vectorizer with SIMD codegen enabled.
This used to require GCC version 4.6 at least, but given that 5.1 is now
the baseline, this check is no longer necessary, and actually
misidentifies Clang as GCC < 4.6 as Clang defines the GCC major/minor as
well, but makes no attempt at doing this in a way that conveys feature
parity with a certain version of GCC (which would not be a great idea in
the first place).
So let's drop the version check, and make the auto-vectorize pragma
(which is based on a GCC-specific command line option) GCC-only. Since
Clang performs SIMD auto-vectorization by default at -O2, no pragma is
necessary here.
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/496
Link: https://github.com/ClangBuiltLinux/linux/issues/503
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Based on 2 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 4122 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
While building arm32 allyesconfig, I ran into the following errors:
arch/arm/lib/xor-neon.c:17:2: error: You should compile this file with
'-mfloat-abi=softfp -mfpu=neon'
In file included from lib/raid6/neon1.c:27:
/home/nathan/cbl/prebuilt/lib/clang/8.0.0/include/arm_neon.h:28:2:
error: "NEON support not enabled"
Building V=1 showed NEON_FLAGS getting passed along to Clang but
__ARM_NEON__ was not getting defined. Ultimately, it boils down to Clang
only defining __ARM_NEON__ when targeting armv7, rather than armv6k,
which is the '-march' value for allyesconfig.
>From lib/Basic/Targets/ARM.cpp in the Clang source:
// This only gets set when Neon instructions are actually available, unlike
// the VFP define, hence the soft float and arch check. This is subtly
// different from gcc, we follow the intent which was that it should be set
// when Neon instructions are actually available.
if ((FPU & NeonFPU) && !SoftFloat && ArchVersion >= 7) {
Builder.defineMacro("__ARM_NEON", "1");
Builder.defineMacro("__ARM_NEON__");
// current AArch32 NEON implementations do not support double-precision
// floating-point even when it is present in VFP.
Builder.defineMacro("__ARM_NEON_FP",
"0x" + Twine::utohexstr(HW_FP & ~HW_FP_DP));
}
Ard Biesheuvel recommended explicitly adding '-march=armv7-a' at the
beginning of the NEON_FLAGS definitions so that __ARM_NEON__ always gets
definined by Clang. This doesn't functionally change anything because
that code will only run where NEON is supported, which is implicitly
armv7.
Link: https://github.com/ClangBuiltLinux/linux/issues/287
Suggested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Commit 0195659 introduced a NEON accelerated version of the xor_blocks()
function, but it needs the changes in this patch to allow it to be built
as a module rather than statically into the kernel.
This patch creates a separate module xor-neon.ko which exports the NEON
inner xor_blocks() functions depended upon by the regular xor.ko if it
is built with CONFIG_KERNEL_MODE_NEON=y
Reported-by: Josh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Add a source file xor-neon.c (which is really just the reference
C implementation passed through the GCC vectorizer) and hook it
up to the XOR framework.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Ard Biesheuvel