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1/*2 * Copyright 2017, Matt Brown, IBM Corp.3 *4 * This program is free software; you can redistribute it and/or5 * modify it under the terms of the GNU General Public License6 * as published by the Free Software Foundation; either version7 * 2 of the License, or (at your option) any later version.8 *9 * vpermxor$#.c10 *11 * Based on H. Peter Anvin's paper - The mathematics of RAID-612 *13 * $#-way unrolled portable integer math RAID-6 instruction set14 * This file is postprocessed using unroll.awk15 *16 * vpermxor$#.c makes use of the vpermxor instruction to optimise the RAID6 Q17 * syndrome calculations.18 * This can be run on systems which have both Altivec and vpermxor instruction.19 *20 * This instruction was introduced in POWER8 - ISA v2.07.21 */22 23#include <linux/raid/pq.h>24#ifdef CONFIG_ALTIVEC25 26#include <altivec.h>27#include <asm/ppc-opcode.h>28#ifdef __KERNEL__29#include <asm/cputable.h>30#include <asm/switch_to.h>31#endif32 33typedef vector unsigned char unative_t;34#define NSIZE sizeof(unative_t)35 36static const vector unsigned char gf_low = {0x1e, 0x1c, 0x1a, 0x18, 0x16, 0x14,37 0x12, 0x10, 0x0e, 0x0c, 0x0a, 0x08,38 0x06, 0x04, 0x02,0x00};39static const vector unsigned char gf_high = {0xfd, 0xdd, 0xbd, 0x9d, 0x7d, 0x5d,40 0x3d, 0x1d, 0xe0, 0xc0, 0xa0, 0x80,41 0x60, 0x40, 0x20, 0x00};42 43static void noinline raid6_vpermxor$#_gen_syndrome_real(int disks, size_t bytes,44 void **ptrs)45{46 u8 **dptr = (u8 **)ptrs;47 u8 *p, *q;48 int d, z, z0;49 unative_t wp$$, wq$$, wd$$;50 51 z0 = disks - 3; /* Highest data disk */52 p = dptr[z0+1]; /* XOR parity */53 q = dptr[z0+2]; /* RS syndrome */54 55 for (d = 0; d < bytes; d += NSIZE*$#) {56 wp$$ = wq$$ = *(unative_t *)&dptr[z0][d+$$*NSIZE];57 58 for (z = z0-1; z>=0; z--) {59 wd$$ = *(unative_t *)&dptr[z][d+$$*NSIZE];60 /* P syndrome */61 wp$$ = vec_xor(wp$$, wd$$);62 63 /* Q syndrome */64 asm(VPERMXOR(%0,%1,%2,%3):"=v"(wq$$):"v"(gf_high), "v"(gf_low), "v"(wq$$));65 wq$$ = vec_xor(wq$$, wd$$);66 }67 *(unative_t *)&p[d+NSIZE*$$] = wp$$;68 *(unative_t *)&q[d+NSIZE*$$] = wq$$;69 }70}71 72static void raid6_vpermxor$#_gen_syndrome(int disks, size_t bytes, void **ptrs)73{74 preempt_disable();75 enable_kernel_altivec();76 77 raid6_vpermxor$#_gen_syndrome_real(disks, bytes, ptrs);78 79 disable_kernel_altivec();80 preempt_enable();81}82 83int raid6_have_altivec_vpermxor(void);84#if $# == 185int raid6_have_altivec_vpermxor(void)86{87 /* Check if arch has both altivec and the vpermxor instructions */88# ifdef __KERNEL__89 return (cpu_has_feature(CPU_FTR_ALTIVEC_COMP) &&90 cpu_has_feature(CPU_FTR_ARCH_207S));91# else92 return 1;93#endif94 95}96#endif97 98const struct raid6_calls raid6_vpermxor$# = {99 raid6_vpermxor$#_gen_syndrome,100 NULL,101 raid6_have_altivec_vpermxor,102 "vpermxor$#",103 0104};105#endif106