1// SPDX-License-Identifier: GPL-2.0-or-later 2/* -*- linux-c -*- ------------------------------------------------------- * 3 * 4 * Copyright 2002 H. Peter Anvin - All Rights Reserved 5 * 6 * ----------------------------------------------------------------------- */ 7 8/* 9 * raid6/algos.c 10 * 11 * Algorithm list and algorithm selection for RAID-6 12 */ 13 14#include <linux/raid/pq.h> 15#ifndef __KERNEL__ 16#include <sys/mman.h> 17#include <stdio.h> 18#else 19#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#endif 25 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_AVX512 32 &raid6_avx512x2, 33 &raid6_avx512x1, 34#endif 35 &raid6_avx2x2, 36 &raid6_avx2x1, 37 &raid6_sse2x2, 38 &raid6_sse2x1, 39 &raid6_sse1x2, 40 &raid6_sse1x1, 41 &raid6_mmxx2, 42 &raid6_mmxx1, 43#endif 44#if defined(__x86_64__) && !defined(__arch_um__) 45#ifdef CONFIG_AS_AVX512 46 &raid6_avx512x4, 47 &raid6_avx512x2, 48 &raid6_avx512x1, 49#endif 50 &raid6_avx2x4, 51 &raid6_avx2x2, 52 &raid6_avx2x1, 53 &raid6_sse2x4, 54 &raid6_sse2x2, 55 &raid6_sse2x1, 56#endif 57#ifdef CONFIG_ALTIVEC 58 &raid6_vpermxor8, 59 &raid6_vpermxor4, 60 &raid6_vpermxor2, 61 &raid6_vpermxor1, 62 &raid6_altivec8, 63 &raid6_altivec4, 64 &raid6_altivec2, 65 &raid6_altivec1, 66#endif 67#if defined(CONFIG_S390) 68 &raid6_s390vx8, 69#endif 70#ifdef CONFIG_KERNEL_MODE_NEON 71 &raid6_neonx8, 72 &raid6_neonx4, 73 &raid6_neonx2, 74 &raid6_neonx1, 75#endif 76#ifdef CONFIG_LOONGARCH 77#ifdef CONFIG_CPU_HAS_LASX 78 &raid6_lasx, 79#endif 80#ifdef CONFIG_CPU_HAS_LSX 81 &raid6_lsx, 82#endif 83#endif 84 &raid6_intx8, 85 &raid6_intx4, 86 &raid6_intx2, 87 &raid6_intx1, 88 NULL 89}; 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_X86 99#ifdef CONFIG_AS_AVX512 100 &raid6_recov_avx512, 101#endif 102 &raid6_recov_avx2, 103 &raid6_recov_ssse3, 104#endif 105#ifdef CONFIG_S390 106 &raid6_recov_s390xc, 107#endif 108#if defined(CONFIG_KERNEL_MODE_NEON) 109 &raid6_recov_neon, 110#endif 111#ifdef CONFIG_LOONGARCH 112#ifdef CONFIG_CPU_HAS_LASX 113 &raid6_recov_lasx, 114#endif 115#ifdef CONFIG_CPU_HAS_LSX 116 &raid6_recov_lsx, 117#endif 118#endif 119 &raid6_recov_intx1, 120 NULL 121}; 122 123#ifdef __KERNEL__ 124#define RAID6_TIME_JIFFIES_LG2 4 125#else 126/* Need more time to be stable in userspace */ 127#define RAID6_TIME_JIFFIES_LG2 9 128#define time_before(x, y) ((x) < (y)) 129#endif 130 131#define RAID6_TEST_DISKS 8 132#define RAID6_TEST_DISKS_ORDER 3 133 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 } else 150 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