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