| /* |
| * 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 |