module/zcommon/zfs_fletcher_aarch64_neon.c

   1 /*
   2  * Implement fast Fletcher4 with NEON instructions. (aarch64)
   3  *
   4  * Use the 128-bit NEON SIMD instructions and registers to compute
   5  * Fletcher4 in two incremental 64-bit parallel accumulator streams,
   6  * and then combine the streams to form the final four checksum words.
   7  * This implementation is a derivative of the AVX SIMD implementation by
   8  * James Guilford and Jinshan Xiong from Intel (see zfs_fletcher_intel.c).
   9  *
  10  * Copyright (C) 2016 Romain Dolbeau.
  11  *
  12  * Authors:
  13  *      Romain Dolbeau <romain.dolbeau@atos.net>
  14  *
  15  * This software is available to you under a choice of one of two
  16  * licenses.  You may choose to be licensed under the terms of the GNU
  17  * General Public License (GPL) Version 2, available from the file
  18  * COPYING in the main directory of this source tree, or the
  19  * OpenIB.org BSD license below:
  20  *
  21  *     Redistribution and use in source and binary forms, with or
  22  *     without modification, are permitted provided that the following
  23  *     conditions are met:
  24  *
  25  *      - Redistributions of source code must retain the above
  26  *        copyright notice, this list of conditions and the following
  27  *        disclaimer.
  28  *
  29  *      - Redistributions in binary form must reproduce the above
  30  *        copyright notice, this list of conditions and the following
  31  *        disclaimer in the documentation and/or other materials
  32  *        provided with the distribution.
  33  *
  34  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  35  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  36  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  37  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  38  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  39  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  40  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  41  * SOFTWARE.
  42  */
  43
  44 #if defined(__aarch64__)
  45
  46 #include <sys/simd.h>
  47 #include <sys/spa_checksum.h>
  48 #include <sys/string.h>
  49 #include <zfs_fletcher.h>
  50
  51 static void
  52 fletcher_4_aarch64_neon_init(fletcher_4_ctx_t *ctx)
  53 {
  54         memset(ctx->aarch64_neon, 0, 4 * sizeof (zfs_fletcher_aarch64_neon_t));
  55 }
  56
  57 static void
  58 fletcher_4_aarch64_neon_fini(fletcher_4_ctx_t *ctx, zio_cksum_t *zcp)
  59 {
  60         uint64_t A, B, C, D;
  61         A = ctx->aarch64_neon[0].v[0] + ctx->aarch64_neon[0].v[1];
  62         B = 2 * ctx->aarch64_neon[1].v[0] + 2 * ctx->aarch64_neon[1].v[1] -
  63             ctx->aarch64_neon[0].v[1];
  64         C = 4 * ctx->aarch64_neon[2].v[0] - ctx->aarch64_neon[1].v[0] +
  65             4 * ctx->aarch64_neon[2].v[1] - 3 * ctx->aarch64_neon[1].v[1];
  66         D = 8 * ctx->aarch64_neon[3].v[0] - 4 * ctx->aarch64_neon[2].v[0] +
  67             8 * ctx->aarch64_neon[3].v[1] - 8 * ctx->aarch64_neon[2].v[1] +
  68             ctx->aarch64_neon[1].v[1];
  69         ZIO_SET_CHECKSUM(zcp, A, B, C, D);
  70 }
  71
  72 #define NEON_INIT_LOOP()                        \
  73         asm("eor %[ZERO].16b,%[ZERO].16b,%[ZERO].16b\n" \
  74         "ld1 { %[ACC0].4s }, %[CTX0]\n"         \
  75         "ld1 { %[ACC1].4s }, %[CTX1]\n"         \
  76         "ld1 { %[ACC2].4s }, %[CTX2]\n"         \
  77         "ld1 { %[ACC3].4s }, %[CTX3]\n"         \
  78         : [ZERO] "=w" (ZERO),                   \
  79         [ACC0] "=w" (ACC0), [ACC1] "=w" (ACC1), \
  80         [ACC2] "=w" (ACC2), [ACC3] "=w" (ACC3)  \
  81         : [CTX0] "Q" (ctx->aarch64_neon[0]),    \
  82         [CTX1] "Q" (ctx->aarch64_neon[1]),      \
  83         [CTX2] "Q" (ctx->aarch64_neon[2]),      \
  84         [CTX3] "Q" (ctx->aarch64_neon[3]))
  85
  86 #define NEON_DO_REVERSE "rev32 %[SRC].16b, %[SRC].16b\n"
  87
  88 #define NEON_DONT_REVERSE ""
  89
  90 #define NEON_MAIN_LOOP(REVERSE)                         \
  91         asm("ld1 { %[SRC].4s }, %[IP]\n"                \
  92         REVERSE                                         \
  93         "zip1 %[TMP1].4s, %[SRC].4s, %[ZERO].4s\n"      \
  94         "zip2 %[TMP2].4s, %[SRC].4s, %[ZERO].4s\n"      \
  95         "add %[ACC0].2d, %[ACC0].2d, %[TMP1].2d\n"      \
  96         "add %[ACC1].2d, %[ACC1].2d, %[ACC0].2d\n"      \
  97         "add %[ACC2].2d, %[ACC2].2d, %[ACC1].2d\n"      \
  98         "add %[ACC3].2d, %[ACC3].2d, %[ACC2].2d\n"      \
  99         "add %[ACC0].2d, %[ACC0].2d, %[TMP2].2d\n"      \
 100         "add %[ACC1].2d, %[ACC1].2d, %[ACC0].2d\n"      \
 101         "add %[ACC2].2d, %[ACC2].2d, %[ACC1].2d\n"      \
 102         "add %[ACC3].2d, %[ACC3].2d, %[ACC2].2d\n"      \
 103         : [SRC] "=&w" (SRC),                            \
 104         [TMP1] "=&w" (TMP1), [TMP2] "=&w" (TMP2),       \
 105         [ACC0] "+w" (ACC0), [ACC1] "+w" (ACC1),         \
 106         [ACC2] "+w" (ACC2), [ACC3] "+w" (ACC3)          \
 107         : [ZERO] "w" (ZERO), [IP] "Q" (*ip))
 108
 109 #define NEON_FINI_LOOP()                        \
 110         asm("st1 { %[ACC0].4s },%[DST0]\n"      \
 111         "st1 { %[ACC1].4s },%[DST1]\n"          \
 112         "st1 { %[ACC2].4s },%[DST2]\n"          \
 113         "st1 { %[ACC3].4s },%[DST3]\n"          \
 114         : [DST0] "=Q" (ctx->aarch64_neon[0]),   \
 115         [DST1] "=Q" (ctx->aarch64_neon[1]),     \
 116         [DST2] "=Q" (ctx->aarch64_neon[2]),     \
 117         [DST3] "=Q" (ctx->aarch64_neon[3])      \
 118         : [ACC0] "w" (ACC0), [ACC1] "w" (ACC1), \
 119         [ACC2] "w" (ACC2), [ACC3] "w" (ACC3))
 120
 121 static void
 122 fletcher_4_aarch64_neon_native(fletcher_4_ctx_t *ctx,
 123     const void *buf, uint64_t size)
 124 {
 125         const uint64_t *ip = buf;
 126         const uint64_t *ipend = (uint64_t *)((uint8_t *)ip + size);
 127 #if defined(_KERNEL)
 128 register unsigned char ZERO asm("v0") __attribute__((vector_size(16)));
 129 register unsigned char ACC0 asm("v1") __attribute__((vector_size(16)));
 130 register unsigned char ACC1 asm("v2") __attribute__((vector_size(16)));
 131 register unsigned char ACC2 asm("v3") __attribute__((vector_size(16)));
 132 register unsigned char ACC3 asm("v4") __attribute__((vector_size(16)));
 133 register unsigned char TMP1 asm("v5") __attribute__((vector_size(16)));
 134 register unsigned char TMP2 asm("v6") __attribute__((vector_size(16)));
 135 register unsigned char SRC asm("v7") __attribute__((vector_size(16)));
 136 #else
 137 unsigned char ZERO __attribute__((vector_size(16)));
 138 unsigned char ACC0 __attribute__((vector_size(16)));
 139 unsigned char ACC1 __attribute__((vector_size(16)));
 140 unsigned char ACC2 __attribute__((vector_size(16)));
 141 unsigned char ACC3 __attribute__((vector_size(16)));
 142 unsigned char TMP1 __attribute__((vector_size(16)));
 143 unsigned char TMP2 __attribute__((vector_size(16)));
 144 unsigned char SRC __attribute__((vector_size(16)));
 145 #endif
 146
 147         NEON_INIT_LOOP();
 148
 149         do {
 150                 NEON_MAIN_LOOP(NEON_DONT_REVERSE);
 151         } while ((ip += 2) < ipend);
 152
 153         NEON_FINI_LOOP();
 154 }
 155
 156 static void
 157 fletcher_4_aarch64_neon_byteswap(fletcher_4_ctx_t *ctx,
 158     const void *buf, uint64_t size)
 159 {
 160         const uint64_t *ip = buf;
 161         const uint64_t *ipend = (uint64_t *)((uint8_t *)ip + size);
 162 #if defined(_KERNEL)
 163 register unsigned char ZERO asm("v0") __attribute__((vector_size(16)));
 164 register unsigned char ACC0 asm("v1") __attribute__((vector_size(16)));
 165 register unsigned char ACC1 asm("v2") __attribute__((vector_size(16)));
 166 register unsigned char ACC2 asm("v3") __attribute__((vector_size(16)));
 167 register unsigned char ACC3 asm("v4") __attribute__((vector_size(16)));
 168 register unsigned char TMP1 asm("v5") __attribute__((vector_size(16)));
 169 register unsigned char TMP2 asm("v6") __attribute__((vector_size(16)));
 170 register unsigned char SRC asm("v7") __attribute__((vector_size(16)));
 171 #else
 172 unsigned char ZERO __attribute__((vector_size(16)));
 173 unsigned char ACC0 __attribute__((vector_size(16)));
 174 unsigned char ACC1 __attribute__((vector_size(16)));
 175 unsigned char ACC2 __attribute__((vector_size(16)));
 176 unsigned char ACC3 __attribute__((vector_size(16)));
 177 unsigned char TMP1 __attribute__((vector_size(16)));
 178 unsigned char TMP2 __attribute__((vector_size(16)));
 179 unsigned char SRC __attribute__((vector_size(16)));
 180 #endif
 181
 182         NEON_INIT_LOOP();
 183
 184         do {
 185                 NEON_MAIN_LOOP(NEON_DO_REVERSE);
 186         } while ((ip += 2) < ipend);
 187
 188         NEON_FINI_LOOP();
 189 }
 190
 191 static boolean_t fletcher_4_aarch64_neon_valid(void)
 192 {
 193         return (kfpu_allowed());
 194 }
 195
 196 const fletcher_4_ops_t fletcher_4_aarch64_neon_ops = {
 197         .init_native = fletcher_4_aarch64_neon_init,
 198         .compute_native = fletcher_4_aarch64_neon_native,
 199         .fini_native = fletcher_4_aarch64_neon_fini,
 200         .init_byteswap = fletcher_4_aarch64_neon_init,
 201         .compute_byteswap = fletcher_4_aarch64_neon_byteswap,
 202         .fini_byteswap = fletcher_4_aarch64_neon_fini,
 203         .valid = fletcher_4_aarch64_neon_valid,
 204         .uses_fpu = B_TRUE,
 205         .name = "aarch64_neon"
 206 };
 207
 208 #endif /* defined(__aarch64__) */