projects / mirror_ubuntu-jammy-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| 751ba79c MB |
1 | /* |
| 2 | * Copyright 2017, Matt Brown, IBM Corp. | |
| 3 | * | |
| 4 | * This program is free software; you can redistribute it and/or | |
| 5 | * modify it under the terms of the GNU General Public License | |
| 6 | * as published by the Free Software Foundation; either version | |
| 7 | * 2 of the License, or (at your option) any later version. | |
| 8 | * | |
| 9 | * vpermxor$#.c | |
| 10 | * | |
| 11 | * Based on H. Peter Anvin's paper - The mathematics of RAID-6 | |
| 12 | * | |
| 13 | * $#-way unrolled portable integer math RAID-6 instruction set | |
| 14 | * This file is postprocessed using unroll.awk | |
| 15 | * | |
| 16 | * vpermxor$#.c makes use of the vpermxor instruction to optimise the RAID6 Q | |
| 17 | * syndrome calculations. | |
| 18 | * This can be run on systems which have both Altivec and vpermxor instruction. | |
| 19 | * | |
| 20 | * This instruction was introduced in POWER8 - ISA v2.07. | |
| 21 | */ | |
| 22 | ||
| 23 | #include <linux/raid/pq.h> | |
| 24 | #ifdef CONFIG_ALTIVEC | |
| 25 | ||
| 26 | #include <altivec.h> | |
| 27 | #ifdef __KERNEL__ | |
| 28 | #include <asm/cputable.h> | |
| 29 | #include <asm/ppc-opcode.h> | |
| 30 | #include <asm/switch_to.h> | |
| 31 | #endif | |
| 32 | ||
| 33 | typedef vector unsigned char unative_t; | |
| 34 | #define NSIZE sizeof(unative_t) | |
| 35 | ||
| 36 | static const vector unsigned char gf_low = {0x1e, 0x1c, 0x1a, 0x18, 0x16, 0x14, | |
| 37 | 0x12, 0x10, 0x0e, 0x0c, 0x0a, 0x08, | |
| 38 | 0x06, 0x04, 0x02,0x00}; | |
| 39 | static const vector unsigned char gf_high = {0xfd, 0xdd, 0xbd, 0x9d, 0x7d, 0x5d, | |
| 40 | 0x3d, 0x1d, 0xe0, 0xc0, 0xa0, 0x80, | |
| 41 | 0x60, 0x40, 0x20, 0x00}; | |
| 42 | ||
| 43 | static void noinline raid6_vpermxor$#_gen_syndrome_real(int disks, size_t bytes, | |
| 44 | void **ptrs) | |
| 45 | { | |
| 46 | u8 **dptr = (u8 **)ptrs; | |
| 47 | u8 *p, *q; | |
| 48 | int d, z, z0; | |
| 49 | unative_t wp$$, wq$$, wd$$; | |
| 50 | ||
| 51 | z0 = disks - 3; /* Highest data disk */ | |
| 52 | p = dptr[z0+1]; /* XOR parity */ | |
| 53 | q = dptr[z0+2]; /* RS syndrome */ | |
| 54 | ||
| 55 | for (d = 0; d < bytes; d += NSIZE*$#) { | |
| 56 | wp$$ = wq$$ = *(unative_t *)&dptr[z0][d+$$*NSIZE]; | |
| 57 | ||
| 58 | for (z = z0-1; z>=0; z--) { | |
| 59 | wd$$ = *(unative_t *)&dptr[z][d+$$*NSIZE]; | |
| 60 | /* P syndrome */ | |
| 61 | wp$$ = vec_xor(wp$$, wd$$); | |
| 62 | ||
| 63 | /* Q syndrome */ | |
| 64 | asm(VPERMXOR(%0,%1,%2,%3):"=v"(wq$$):"v"(gf_high), "v"(gf_low), "v"(wq$$)); | |
| 65 | wq$$ = vec_xor(wq$$, wd$$); | |
| 66 | } | |
| 67 | *(unative_t *)&p[d+NSIZE*$$] = wp$$; | |
| 68 | *(unative_t *)&q[d+NSIZE*$$] = wq$$; | |
| 69 | } | |
| 70 | } | |
| 71 | ||
| 72 | static void raid6_vpermxor$#_gen_syndrome(int disks, size_t bytes, void **ptrs) | |
| 73 | { | |
| 74 | preempt_disable(); | |
| 75 | enable_kernel_altivec(); | |
| 76 | ||
| 77 | raid6_vpermxor$#_gen_syndrome_real(disks, bytes, ptrs); | |
| 78 | ||
| 79 | disable_kernel_altivec(); | |
| 80 | preempt_enable(); | |
| 81 | } | |
| 82 | ||
| 83 | int raid6_have_altivec_vpermxor(void); | |
| 84 | #if $# == 1 | |
| 85 | int raid6_have_altivec_vpermxor(void) | |
| 86 | { | |
| 87 | /* Check if arch has both altivec and the vpermxor instructions */ | |
| 88 | # ifdef __KERNEL__ | |
| 89 | return (cpu_has_feature(CPU_FTR_ALTIVEC_COMP) && | |
| 90 | cpu_has_feature(CPU_FTR_ARCH_207S)); | |
| 91 | # else | |
| 92 | return 1; | |
| 93 | #endif | |
| 94 | ||
| 95 | } | |
| 96 | #endif | |
| 97 | ||
| 98 | const struct raid6_calls raid6_vpermxor$# = { | |
| 99 | raid6_vpermxor$#_gen_syndrome, | |
| 100 | NULL, | |
| 101 | raid6_have_altivec_vpermxor, | |
| 102 | "vpermxor$#", | |
| 103 | 0 | |
| 104 | }; | |
| 105 | #endif |