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Diffstat (limited to 'lib/raid6/vpermxor.uc')
| -rw-r--r-- | lib/raid6/vpermxor.uc | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/lib/raid6/vpermxor.uc b/lib/raid6/vpermxor.uc new file mode 100644 index 000000000..10475dc42 --- /dev/null +++ b/lib/raid6/vpermxor.uc @@ -0,0 +1,105 @@ +/* + * Copyright 2017, Matt Brown, IBM Corp. + * + * 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; either version + * 2 of the License, or (at your option) any later version. + * + * vpermxor$#.c + * + * Based on H. Peter Anvin's paper - The mathematics of RAID-6 + * + * $#-way unrolled portable integer math RAID-6 instruction set + * This file is postprocessed using unroll.awk + * + * vpermxor$#.c makes use of the vpermxor instruction to optimise the RAID6 Q + * syndrome calculations. + * This can be run on systems which have both Altivec and vpermxor instruction. + * + * This instruction was introduced in POWER8 - ISA v2.07. + */ + +#include <linux/raid/pq.h> +#ifdef CONFIG_ALTIVEC + +#include <altivec.h> +#ifdef __KERNEL__ +#include <asm/cputable.h> +#include <asm/ppc-opcode.h> +#include <asm/switch_to.h> +#endif + +typedef vector unsigned char unative_t; +#define NSIZE sizeof(unative_t) + +static const vector unsigned char gf_low = {0x1e, 0x1c, 0x1a, 0x18, 0x16, 0x14, + 0x12, 0x10, 0x0e, 0x0c, 0x0a, 0x08, + 0x06, 0x04, 0x02,0x00}; +static const vector unsigned char gf_high = {0xfd, 0xdd, 0xbd, 0x9d, 0x7d, 0x5d, + 0x3d, 0x1d, 0xe0, 0xc0, 0xa0, 0x80, + 0x60, 0x40, 0x20, 0x00}; + +static void noinline raid6_vpermxor$#_gen_syndrome_real(int disks, size_t bytes, + void **ptrs) +{ + u8 **dptr = (u8 **)ptrs; + u8 *p, *q; + int d, z, z0; + unative_t wp$$, wq$$, wd$$; + + z0 = disks - 3; /* Highest data disk */ + p = dptr[z0+1]; /* XOR parity */ + q = dptr[z0+2]; /* RS syndrome */ + + for (d = 0; d < bytes; d += NSIZE*$#) { + wp$$ = wq$$ = *(unative_t *)&dptr[z0][d+$$*NSIZE]; + + for (z = z0-1; z>=0; z--) { + wd$$ = *(unative_t *)&dptr[z][d+$$*NSIZE]; + /* P syndrome */ + wp$$ = vec_xor(wp$$, wd$$); + + /* Q syndrome */ + asm(VPERMXOR(%0,%1,%2,%3):"=v"(wq$$):"v"(gf_high), "v"(gf_low), "v"(wq$$)); + wq$$ = vec_xor(wq$$, wd$$); + } + *(unative_t *)&p[d+NSIZE*$$] = wp$$; + *(unative_t *)&q[d+NSIZE*$$] = wq$$; + } +} + +static void raid6_vpermxor$#_gen_syndrome(int disks, size_t bytes, void **ptrs) +{ + preempt_disable(); + enable_kernel_altivec(); + + raid6_vpermxor$#_gen_syndrome_real(disks, bytes, ptrs); + + disable_kernel_altivec(); + preempt_enable(); +} + +int raid6_have_altivec_vpermxor(void); +#if $# == 1 +int raid6_have_altivec_vpermxor(void) +{ + /* Check if arch has both altivec and the vpermxor instructions */ +# ifdef __KERNEL__ + return (cpu_has_feature(CPU_FTR_ALTIVEC_COMP) && + cpu_has_feature(CPU_FTR_ARCH_207S)); +# else + return 1; +#endif + +} +#endif + +const struct raid6_calls raid6_vpermxor$# = { + raid6_vpermxor$#_gen_syndrome, + NULL, + raid6_have_altivec_vpermxor, + "vpermxor$#", + 0 +}; +#endif |