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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2013-05-16 17:20:32 +0200
committerArd Biesheuvel <ard.biesheuvel@linaro.org>2013-07-08 22:09:18 +0100
commit7d11965ddb9b9b1e0a5d13c58345ada1ccbc663b (patch)
tree9aec7ff11372f0194f288c13c7c83ff6ef40c87b /lib/raid6/neon.uc
parent01956597cbc46df072f20f90a40eebe356200c38 (diff)
downloadlinux-7d11965ddb9b9b1e0a5d13c58345ada1ccbc663b.tar.bz2
lib/raid6: add ARM-NEON accelerated syndrome calculation
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
Diffstat (limited to 'lib/raid6/neon.uc')
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diff --git a/lib/raid6/neon.uc b/lib/raid6/neon.uc
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+/* -----------------------------------------------------------------------
+ *
+ * neon.uc - RAID-6 syndrome calculation using ARM NEON instructions
+ *
+ * Copyright (C) 2012 Rob Herring
+ *
+ * Based on altivec.uc:
+ * Copyright 2002-2004 H. Peter Anvin - All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ * Boston MA 02111-1307, USA; either version 2 of the License, or
+ * (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * neon$#.c
+ *
+ * $#-way unrolled NEON intrinsics math RAID-6 instruction set
+ *
+ * This file is postprocessed using unroll.awk
+ */
+
+#include <arm_neon.h>
+
+typedef uint8x16_t unative_t;
+
+#define NBYTES(x) ((unative_t){x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x})
+#define NSIZE sizeof(unative_t)
+
+/*
+ * The SHLBYTE() operation shifts each byte left by 1, *not*
+ * rolling over into the next byte
+ */
+static inline unative_t SHLBYTE(unative_t v)
+{
+ return vshlq_n_u8(v, 1);
+}
+
+/*
+ * The MASK() operation returns 0xFF in any byte for which the high
+ * bit is 1, 0x00 for any byte for which the high bit is 0.
+ */
+static inline unative_t MASK(unative_t v)
+{
+ const uint8x16_t temp = NBYTES(0);
+ return (unative_t)vcltq_s8((int8x16_t)v, (int8x16_t)temp);
+}
+
+void raid6_neon$#_gen_syndrome_real(int disks, unsigned long bytes, void **ptrs)
+{
+ uint8_t **dptr = (uint8_t **)ptrs;
+ uint8_t *p, *q;
+ int d, z, z0;
+
+ register unative_t wd$$, wq$$, wp$$, w1$$, w2$$;
+ const unative_t x1d = NBYTES(0x1d);
+
+ z0 = disks - 3; /* Highest data disk */
+ p = dptr[z0+1]; /* XOR parity */
+ q = dptr[z0+2]; /* RS syndrome */
+
+ for ( d = 0 ; d < bytes ; d += NSIZE*$# ) {
+ wq$$ = wp$$ = vld1q_u8(&dptr[z0][d+$$*NSIZE]);
+ for ( z = z0-1 ; z >= 0 ; z-- ) {
+ wd$$ = vld1q_u8(&dptr[z][d+$$*NSIZE]);
+ wp$$ = veorq_u8(wp$$, wd$$);
+ w2$$ = MASK(wq$$);
+ w1$$ = SHLBYTE(wq$$);
+
+ w2$$ = vandq_u8(w2$$, x1d);
+ w1$$ = veorq_u8(w1$$, w2$$);
+ wq$$ = veorq_u8(w1$$, wd$$);
+ }
+ vst1q_u8(&p[d+NSIZE*$$], wp$$);
+ vst1q_u8(&q[d+NSIZE*$$], wq$$);
+ }
+}