LXR linux/lib/raid6/neon.c

   1/*
   2 * linux/lib/raid6/neon.c - RAID6 syndrome calculation using ARM NEON intrinsics
   3 *
   4 * Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org>
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License version 2 as
   8 * published by the Free Software Foundation.
   9 */
  10
  11#include <linux/raid/pq.h>
  12
  13#ifdef __KERNEL__
  14#include <asm/neon.h>
  15#else
  16#define kernel_neon_begin()
  17#define kernel_neon_end()
  18#define cpu_has_neon()          (1)
  19#endif
  20
  21/*
  22 * There are 2 reasons these wrappers are kept in a separate compilation unit
  23 * from the actual implementations in neonN.c (generated from neon.uc by
  24 * unroll.awk):
  25 * - the actual implementations use NEON intrinsics, and the GCC support header
  26 *   (arm_neon.h) is not fully compatible (type wise) with the kernel;
  27 * - the neonN.c files are compiled with -mfpu=neon and optimization enabled,
  28 *   and we have to make sure that we never use *any* NEON/VFP instructions
  29 *   outside a kernel_neon_begin()/kernel_neon_end() pair.
  30 */
  31
  32#define RAID6_NEON_WRAPPER(_n)                                          \
  33        static void raid6_neon ## _n ## _gen_syndrome(int disks,        \
  34                                        size_t bytes, void **ptrs)      \
  35        {                                                               \
  36                void raid6_neon ## _n  ## _gen_syndrome_real(int,       \
  37                                                unsigned long, void**); \
  38                kernel_neon_begin();                                    \
  39                raid6_neon ## _n ## _gen_syndrome_real(disks,           \
  40                                        (unsigned long)bytes, ptrs);    \
  41                kernel_neon_end();                                      \
  42        }                                                               \
  43        static void raid6_neon ## _n ## _xor_syndrome(int disks,        \
  44                                        int start, int stop,            \
  45                                        size_t bytes, void **ptrs)      \
  46        {                                                               \
  47                void raid6_neon ## _n  ## _xor_syndrome_real(int,       \
  48                                int, int, unsigned long, void**);       \
  49                kernel_neon_begin();                                    \
  50                raid6_neon ## _n ## _xor_syndrome_real(disks,           \
  51                        start, stop, (unsigned long)bytes, ptrs);       \
  52                kernel_neon_end();                                      \
  53        }                                                               \
  54        struct raid6_calls const raid6_neonx ## _n = {                  \
  55                raid6_neon ## _n ## _gen_syndrome,                      \
  56                raid6_neon ## _n ## _xor_syndrome,                      \
  57                raid6_have_neon,                                        \
  58                "neonx" #_n,                                            \
  59                0                                                       \
  60        }
  61
  62static int raid6_have_neon(void)
  63{
  64        return cpu_has_neon();
  65}
  66
  67RAID6_NEON_WRAPPER(1);
  68RAID6_NEON_WRAPPER(2);
  69RAID6_NEON_WRAPPER(4);
  70RAID6_NEON_WRAPPER(8);
  71