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1/* -*- linux-c -*- ------------------------------------------------------- *2 *3 * Copyright 2002-2004 H. Peter Anvin - All Rights Reserved4 *5 * This program is free software; you can redistribute it and/or modify6 * it under the terms of the GNU General Public License as published by7 * the Free Software Foundation, Inc., 53 Temple Place Ste 330,8 * Boston MA 02111-1307, USA; either version 2 of the License, or9 * (at your option) any later version; incorporated herein by reference.10 *11 * ----------------------------------------------------------------------- */12 13/*14 * raid6altivec$#.c15 *16 * $#-way unrolled portable integer math RAID-6 instruction set17 *18 * This file is postprocessed using unroll.awk19 *20 * <benh> hpa: in process,21 * you can just "steal" the vec unit with enable_kernel_altivec() (but22 * bracked this with preempt_disable/enable or in a lock)23 */24 25#include <linux/raid/pq.h>26 27#ifdef CONFIG_ALTIVEC28 29#include <altivec.h>30#ifdef __KERNEL__31# include <asm/cputable.h>32# include <asm/switch_to.h>33#endif /* __KERNEL__ */34 35/*36 * This is the C data type to use. We use a vector of37 * signed char so vec_cmpgt() will generate the right38 * instruction.39 */40 41typedef vector signed char unative_t;42 43#define NBYTES(x) ((vector signed char) {x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x})44#define NSIZE sizeof(unative_t)45 46/*47 * The SHLBYTE() operation shifts each byte left by 1, *not*48 * rolling over into the next byte49 */50static inline __attribute_const__ unative_t SHLBYTE(unative_t v)51{52 return vec_add(v,v);53}54 55/*56 * The MASK() operation returns 0xFF in any byte for which the high57 * bit is 1, 0x00 for any byte for which the high bit is 0.58 */59static inline __attribute_const__ unative_t MASK(unative_t v)60{61 unative_t zv = NBYTES(0);62 63 /* vec_cmpgt returns a vector bool char; thus the need for the cast */64 return (unative_t)vec_cmpgt(zv, v);65}66 67 68/* This is noinline to make damned sure that gcc doesn't move any of the69 Altivec code around the enable/disable code */70static void noinline71raid6_altivec$#_gen_syndrome_real(int disks, size_t bytes, void **ptrs)72{73 u8 **dptr = (u8 **)ptrs;74 u8 *p, *q;75 int d, z, z0;76 77 unative_t wd$$, wq$$, wp$$, w1$$, w2$$;78 unative_t x1d = NBYTES(0x1d);79 80 z0 = disks - 3; /* Highest data disk */81 p = dptr[z0+1]; /* XOR parity */82 q = dptr[z0+2]; /* RS syndrome */83 84 for ( d = 0 ; d < bytes ; d += NSIZE*$# ) {85 wq$$ = wp$$ = *(unative_t *)&dptr[z0][d+$$*NSIZE];86 for ( z = z0-1 ; z >= 0 ; z-- ) {87 wd$$ = *(unative_t *)&dptr[z][d+$$*NSIZE];88 wp$$ = vec_xor(wp$$, wd$$);89 w2$$ = MASK(wq$$);90 w1$$ = SHLBYTE(wq$$);91 w2$$ = vec_and(w2$$, x1d);92 w1$$ = vec_xor(w1$$, w2$$);93 wq$$ = vec_xor(w1$$, wd$$);94 }95 *(unative_t *)&p[d+NSIZE*$$] = wp$$;96 *(unative_t *)&q[d+NSIZE*$$] = wq$$;97 }98}99 100static void raid6_altivec$#_gen_syndrome(int disks, size_t bytes, void **ptrs)101{102 preempt_disable();103 enable_kernel_altivec();104 105 raid6_altivec$#_gen_syndrome_real(disks, bytes, ptrs);106 107 disable_kernel_altivec();108 preempt_enable();109}110 111int raid6_have_altivec(void);112#if $# == 1113int raid6_have_altivec(void)114{115 /* This assumes either all CPUs have Altivec or none does */116# ifdef __KERNEL__117 return cpu_has_feature(CPU_FTR_ALTIVEC);118# else119 return 1;120# endif121}122#endif123 124const struct raid6_calls raid6_altivec$# = {125 raid6_altivec$#_gen_syndrome,126 NULL, /* XOR not yet implemented */127 raid6_have_altivec,128 "altivecx$#",129 0130};131 132#endif /* CONFIG_ALTIVEC */133