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1// SPDX-License-Identifier: GPL-2.0-or-later2/* -*- linux-c -*- ------------------------------------------------------- *3 *4 * Copyright 2002 H. Peter Anvin - All Rights Reserved5 *6 * ----------------------------------------------------------------------- */7 8/*9 * raid6/algos.c10 *11 * Algorithm list and algorithm selection for RAID-612 */13 14#include <linux/raid/pq.h>15#ifndef __KERNEL__16#include <sys/mman.h>17#include <stdio.h>18#else19#include <linux/module.h>20#include <linux/gfp.h>21/* In .bss so it's zeroed */22const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256)));23EXPORT_SYMBOL(raid6_empty_zero_page);24#endif25 26struct raid6_calls raid6_call;27EXPORT_SYMBOL_GPL(raid6_call);28 29const struct raid6_calls * const raid6_algos[] = {30#if defined(__i386__) && !defined(__arch_um__)31#ifdef CONFIG_AS_AVX51232 &raid6_avx512x2,33 &raid6_avx512x1,34#endif35 &raid6_avx2x2,36 &raid6_avx2x1,37 &raid6_sse2x2,38 &raid6_sse2x1,39 &raid6_sse1x2,40 &raid6_sse1x1,41 &raid6_mmxx2,42 &raid6_mmxx1,43#endif44#if defined(__x86_64__) && !defined(__arch_um__)45#ifdef CONFIG_AS_AVX51246 &raid6_avx512x4,47 &raid6_avx512x2,48 &raid6_avx512x1,49#endif50 &raid6_avx2x4,51 &raid6_avx2x2,52 &raid6_avx2x1,53 &raid6_sse2x4,54 &raid6_sse2x2,55 &raid6_sse2x1,56#endif57#ifdef CONFIG_ALTIVEC58 &raid6_vpermxor8,59 &raid6_vpermxor4,60 &raid6_vpermxor2,61 &raid6_vpermxor1,62 &raid6_altivec8,63 &raid6_altivec4,64 &raid6_altivec2,65 &raid6_altivec1,66#endif67#if defined(CONFIG_S390)68 &raid6_s390vx8,69#endif70#ifdef CONFIG_KERNEL_MODE_NEON71 &raid6_neonx8,72 &raid6_neonx4,73 &raid6_neonx2,74 &raid6_neonx1,75#endif76#ifdef CONFIG_LOONGARCH77#ifdef CONFIG_CPU_HAS_LASX78 &raid6_lasx,79#endif80#ifdef CONFIG_CPU_HAS_LSX81 &raid6_lsx,82#endif83#endif84 &raid6_intx8,85 &raid6_intx4,86 &raid6_intx2,87 &raid6_intx1,88 NULL89};90 91void (*raid6_2data_recov)(int, size_t, int, int, void **);92EXPORT_SYMBOL_GPL(raid6_2data_recov);93 94void (*raid6_datap_recov)(int, size_t, int, void **);95EXPORT_SYMBOL_GPL(raid6_datap_recov);96 97const struct raid6_recov_calls *const raid6_recov_algos[] = {98#ifdef CONFIG_X8699#ifdef CONFIG_AS_AVX512100 &raid6_recov_avx512,101#endif102 &raid6_recov_avx2,103 &raid6_recov_ssse3,104#endif105#ifdef CONFIG_S390106 &raid6_recov_s390xc,107#endif108#if defined(CONFIG_KERNEL_MODE_NEON)109 &raid6_recov_neon,110#endif111#ifdef CONFIG_LOONGARCH112#ifdef CONFIG_CPU_HAS_LASX113 &raid6_recov_lasx,114#endif115#ifdef CONFIG_CPU_HAS_LSX116 &raid6_recov_lsx,117#endif118#endif119 &raid6_recov_intx1,120 NULL121};122 123#ifdef __KERNEL__124#define RAID6_TIME_JIFFIES_LG2 4125#else126/* Need more time to be stable in userspace */127#define RAID6_TIME_JIFFIES_LG2 9128#define time_before(x, y) ((x) < (y))129#endif130 131#define RAID6_TEST_DISKS 8132#define RAID6_TEST_DISKS_ORDER 3133 134static inline const struct raid6_recov_calls *raid6_choose_recov(void)135{136 const struct raid6_recov_calls *const *algo;137 const struct raid6_recov_calls *best;138 139 for (best = NULL, algo = raid6_recov_algos; *algo; algo++)140 if (!best || (*algo)->priority > best->priority)141 if (!(*algo)->valid || (*algo)->valid())142 best = *algo;143 144 if (best) {145 raid6_2data_recov = best->data2;146 raid6_datap_recov = best->datap;147 148 pr_info("raid6: using %s recovery algorithm\n", best->name);149 } else150 pr_err("raid6: Yikes! No recovery algorithm found!\n");151 152 return best;153}154 155static inline const struct raid6_calls *raid6_choose_gen(156 void *(*const dptrs)[RAID6_TEST_DISKS], const int disks)157{158 unsigned long perf, bestgenperf, j0, j1;159 int start = (disks>>1)-1, stop = disks-3; /* work on the second half of the disks */160 const struct raid6_calls *const *algo;161 const struct raid6_calls *best;162 163 for (bestgenperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) {164 if (!best || (*algo)->priority >= best->priority) {165 if ((*algo)->valid && !(*algo)->valid())166 continue;167 168 if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK)) {169 best = *algo;170 break;171 }172 173 perf = 0;174 175 preempt_disable();176 j0 = jiffies;177 while ((j1 = jiffies) == j0)178 cpu_relax();179 while (time_before(jiffies,180 j1 + (1<<RAID6_TIME_JIFFIES_LG2))) {181 (*algo)->gen_syndrome(disks, PAGE_SIZE, *dptrs);182 perf++;183 }184 preempt_enable();185 186 if (perf > bestgenperf) {187 bestgenperf = perf;188 best = *algo;189 }190 pr_info("raid6: %-8s gen() %5ld MB/s\n", (*algo)->name,191 (perf * HZ * (disks-2)) >>192 (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2));193 }194 }195 196 if (!best) {197 pr_err("raid6: Yikes! No algorithm found!\n");198 goto out;199 }200 201 raid6_call = *best;202 203 if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK)) {204 pr_info("raid6: skipped pq benchmark and selected %s\n",205 best->name);206 goto out;207 }208 209 pr_info("raid6: using algorithm %s gen() %ld MB/s\n",210 best->name,211 (bestgenperf * HZ * (disks - 2)) >>212 (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2));213 214 if (best->xor_syndrome) {215 perf = 0;216 217 preempt_disable();218 j0 = jiffies;219 while ((j1 = jiffies) == j0)220 cpu_relax();221 while (time_before(jiffies,222 j1 + (1 << RAID6_TIME_JIFFIES_LG2))) {223 best->xor_syndrome(disks, start, stop,224 PAGE_SIZE, *dptrs);225 perf++;226 }227 preempt_enable();228 229 pr_info("raid6: .... xor() %ld MB/s, rmw enabled\n",230 (perf * HZ * (disks - 2)) >>231 (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2 + 1));232 }233 234out:235 return best;236}237 238 239/* Try to pick the best algorithm */240/* This code uses the gfmul table as convenient data set to abuse */241 242int __init raid6_select_algo(void)243{244 const int disks = RAID6_TEST_DISKS;245 246 const struct raid6_calls *gen_best;247 const struct raid6_recov_calls *rec_best;248 char *disk_ptr, *p;249 void *dptrs[RAID6_TEST_DISKS];250 int i, cycle;251 252 /* prepare the buffer and fill it circularly with gfmul table */253 disk_ptr = (char *)__get_free_pages(GFP_KERNEL, RAID6_TEST_DISKS_ORDER);254 if (!disk_ptr) {255 pr_err("raid6: Yikes! No memory available.\n");256 return -ENOMEM;257 }258 259 p = disk_ptr;260 for (i = 0; i < disks; i++)261 dptrs[i] = p + PAGE_SIZE * i;262 263 cycle = ((disks - 2) * PAGE_SIZE) / 65536;264 for (i = 0; i < cycle; i++) {265 memcpy(p, raid6_gfmul, 65536);266 p += 65536;267 }268 269 if ((disks - 2) * PAGE_SIZE % 65536)270 memcpy(p, raid6_gfmul, (disks - 2) * PAGE_SIZE % 65536);271 272 /* select raid gen_syndrome function */273 gen_best = raid6_choose_gen(&dptrs, disks);274 275 /* select raid recover functions */276 rec_best = raid6_choose_recov();277 278 free_pages((unsigned long)disk_ptr, RAID6_TEST_DISKS_ORDER);279 280 return gen_best && rec_best ? 0 : -EINVAL;281}282 283static void raid6_exit(void)284{285 do { } while (0);286}287 288subsys_initcall(raid6_select_algo);289module_exit(raid6_exit);290MODULE_LICENSE("GPL");291MODULE_DESCRIPTION("RAID6 Q-syndrome calculations");292