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
  62 static int raid6_have_neon(void)
  63 {
  64         return cpu_has_neon();
  65 }
  66
  67 RAID6_NEON_WRAPPER(1);
  68 RAID6_NEON_WRAPPER(2);
  69 RAID6_NEON_WRAPPER(4);
  70 RAID6_NEON_WRAPPER(8);