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Diffstat (limited to 'lib/raid6/altivec.uc')
| -rw-r--r-- | lib/raid6/altivec.uc | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/lib/raid6/altivec.uc b/lib/raid6/altivec.uc new file mode 100644 index 000000000..bec27fce7 --- /dev/null +++ b/lib/raid6/altivec.uc @@ -0,0 +1,128 @@ +/* -*- linux-c -*- ------------------------------------------------------- * + * + * 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. + * + * ----------------------------------------------------------------------- */ + +/* + * raid6altivec$#.c + * + * $#-way unrolled portable integer math RAID-6 instruction set + * + * This file is postprocessed using unroll.awk + * + * <benh> hpa: in process, + * you can just "steal" the vec unit with enable_kernel_altivec() (but + * bracked this with preempt_disable/enable or in a lock) + */ + +#include <linux/raid/pq.h> + +#include <altivec.h> +#ifdef __KERNEL__ +# include <asm/cputable.h> +# include <asm/switch_to.h> + +/* + * This is the C data type to use. We use a vector of + * signed char so vec_cmpgt() will generate the right + * instruction. + */ + +typedef vector signed char unative_t; + +#define NBYTES(x) ((vector signed char) {x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x}) +#define NSIZE sizeof(unative_t) + +/* + * The SHLBYTE() operation shifts each byte left by 1, *not* + * rolling over into the next byte + */ +static inline __attribute_const__ unative_t SHLBYTE(unative_t v) +{ + return vec_add(v,v); +} + +/* + * The MASK() operation returns 0xFF in any byte for which the high + * bit is 1, 0x00 for any byte for which the high bit is 0. + */ +static inline __attribute_const__ unative_t MASK(unative_t v) +{ + unative_t zv = NBYTES(0); + + /* vec_cmpgt returns a vector bool char; thus the need for the cast */ + return (unative_t)vec_cmpgt(zv, v); +} + + +/* This is noinline to make damned sure that gcc doesn't move any of the + Altivec code around the enable/disable code */ +static void noinline +raid6_altivec$#_gen_syndrome_real(int disks, size_t bytes, void **ptrs) +{ + u8 **dptr = (u8 **)ptrs; + u8 *p, *q; + int d, z, z0; + + unative_t wd$$, wq$$, wp$$, w1$$, w2$$; + unative_t x1d = NBYTES(0x1d); + + z0 = disks - 3; /* Highest data disk */ + p = dptr[z0+1]; /* XOR parity */ + q = dptr[z0+2]; /* RS syndrome */ + + for ( d = 0 ; d < bytes ; d += NSIZE*$# ) { + wq$$ = wp$$ = *(unative_t *)&dptr[z0][d+$$*NSIZE]; + for ( z = z0-1 ; z >= 0 ; z-- ) { + wd$$ = *(unative_t *)&dptr[z][d+$$*NSIZE]; + wp$$ = vec_xor(wp$$, wd$$); + w2$$ = MASK(wq$$); + w1$$ = SHLBYTE(wq$$); + w2$$ = vec_and(w2$$, x1d); + w1$$ = vec_xor(w1$$, w2$$); + wq$$ = vec_xor(w1$$, wd$$); + } + *(unative_t *)&p[d+NSIZE*$$] = wp$$; + *(unative_t *)&q[d+NSIZE*$$] = wq$$; + } +} + +static void raid6_altivec$#_gen_syndrome(int disks, size_t bytes, void **ptrs) +{ + preempt_disable(); + enable_kernel_altivec(); + + raid6_altivec$#_gen_syndrome_real(disks, bytes, ptrs); + + preempt_enable(); +} + +int raid6_have_altivec(void); +#if $# == 1 +int raid6_have_altivec(void) +{ + /* This assumes either all CPUs have Altivec or none does */ +# ifdef __KERNEL__ + return cpu_has_feature(CPU_FTR_ALTIVEC); +# else + return 1; +# endif +} +#endif + +const struct raid6_calls raid6_altivec$# = { + raid6_altivec$#_gen_syndrome, + NULL, /* XOR not yet implemented */ + raid6_have_altivec, + "altivecx$#", + 0 +}; + +#endif /* CONFIG_ALTIVEC */ |