7d11965ddb
Rebased/reworked a patch contributed by Rob Herring that uses NEON intrinsics to perform the RAID-6 syndrome calculations. It uses the existing unroll.awk code to generate several unrolled versions of which the best performing one is selected at boot time. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Nicolas Pitre <nico@linaro.org> Cc: hpa@linux.intel.com
58 lines
1.7 KiB
C
58 lines
1.7 KiB
C
/*
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* linux/lib/raid6/neon.c - RAID6 syndrome calculation using ARM NEON intrinsics
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*
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* Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/raid/pq.h>
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#ifdef __KERNEL__
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#include <asm/neon.h>
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#else
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#define kernel_neon_begin()
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#define kernel_neon_end()
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#define cpu_has_neon() (1)
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#endif
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/*
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* There are 2 reasons these wrappers are kept in a separate compilation unit
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* from the actual implementations in neonN.c (generated from neon.uc by
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* unroll.awk):
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* - the actual implementations use NEON intrinsics, and the GCC support header
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* (arm_neon.h) is not fully compatible (type wise) with the kernel;
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* - the neonN.c files are compiled with -mfpu=neon and optimization enabled,
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* and we have to make sure that we never use *any* NEON/VFP instructions
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* outside a kernel_neon_begin()/kernel_neon_end() pair.
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*/
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#define RAID6_NEON_WRAPPER(_n) \
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static void raid6_neon ## _n ## _gen_syndrome(int disks, \
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size_t bytes, void **ptrs) \
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{ \
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void raid6_neon ## _n ## _gen_syndrome_real(int, \
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unsigned long, void**); \
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kernel_neon_begin(); \
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raid6_neon ## _n ## _gen_syndrome_real(disks, \
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(unsigned long)bytes, ptrs); \
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kernel_neon_end(); \
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} \
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struct raid6_calls const raid6_neonx ## _n = { \
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raid6_neon ## _n ## _gen_syndrome, \
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raid6_have_neon, \
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"neonx" #_n, \
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0 \
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}
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static int raid6_have_neon(void)
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{
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return cpu_has_neon();
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}
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RAID6_NEON_WRAPPER(1);
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RAID6_NEON_WRAPPER(2);
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RAID6_NEON_WRAPPER(4);
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RAID6_NEON_WRAPPER(8);
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