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 #if !RAID6_USE_EMPTY_ZERO_PAGE 22 /* In .bss so it's zeroed */ 23 const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256))); 24 EXPORT_SYMBOL(raid6_empty_zero_page); 25 #endif 26 #endif 27 28 struct raid6_calls raid6_call; 29 EXPORT_SYMBOL_GPL(raid6_call); 30 31 const struct raid6_calls * const raid6_algos[] = { 32 #if defined(__i386__) && !defined(__arch_um__) 33 #ifdef CONFIG_AS_AVX512 34 &raid6_avx512x2, 35 &raid6_avx512x1, 36 #endif 37 #ifdef CONFIG_AS_AVX2 38 &raid6_avx2x2, 39 &raid6_avx2x1, 40 #endif 41 &raid6_sse2x2, 42 &raid6_sse2x1, 43 &raid6_sse1x2, 44 &raid6_sse1x1, 45 &raid6_mmxx2, 46 &raid6_mmxx1, 47 #endif 48 #if defined(__x86_64__) && !defined(__arch_um__) 49 #ifdef CONFIG_AS_AVX512 50 &raid6_avx512x4, 51 &raid6_avx512x2, 52 &raid6_avx512x1, 53 #endif 54 #ifdef CONFIG_AS_AVX2 55 &raid6_avx2x4, 56 &raid6_avx2x2, 57 &raid6_avx2x1, 58 #endif 59 &raid6_sse2x4, 60 &raid6_sse2x2, 61 &raid6_sse2x1, 62 #endif 63 #ifdef CONFIG_ALTIVEC 64 &raid6_vpermxor8, 65 &raid6_vpermxor4, 66 &raid6_vpermxor2, 67 &raid6_vpermxor1, 68 &raid6_altivec8, 69 &raid6_altivec4, 70 &raid6_altivec2, 71 &raid6_altivec1, 72 #endif 73 #if defined(CONFIG_S390) 74 &raid6_s390vx8, 75 #endif 76 #ifdef CONFIG_KERNEL_MODE_NEON 77 &raid6_neonx8, 78 &raid6_neonx4, 79 &raid6_neonx2, 80 &raid6_neonx1, 81 #endif 82 #if defined(__ia64__) 83 &raid6_intx32, 84 &raid6_intx16, 85 #endif 86 &raid6_intx8, 87 &raid6_intx4, 88 &raid6_intx2, 89 &raid6_intx1, 90 NULL 91 }; 92 93 void (*raid6_2data_recov)(int, size_t, int, int, void **); 94 EXPORT_SYMBOL_GPL(raid6_2data_recov); 95 96 void (*raid6_datap_recov)(int, size_t, int, void **); 97 EXPORT_SYMBOL_GPL(raid6_datap_recov); 98 99 const struct raid6_recov_calls *const raid6_recov_algos[] = { 100 #ifdef CONFIG_AS_AVX512 101 &raid6_recov_avx512, 102 #endif 103 #ifdef CONFIG_AS_AVX2 104 &raid6_recov_avx2, 105 #endif 106 #ifdef CONFIG_AS_SSSE3 107 &raid6_recov_ssse3, 108 #endif 109 #ifdef CONFIG_S390 110 &raid6_recov_s390xc, 111 #endif 112 #if defined(CONFIG_KERNEL_MODE_NEON) 113 &raid6_recov_neon, 114 #endif 115 &raid6_recov_intx1, 116 NULL 117 }; 118 119 #ifdef __KERNEL__ 120 #define RAID6_TIME_JIFFIES_LG2 4 121 #else 122 /* Need more time to be stable in userspace */ 123 #define RAID6_TIME_JIFFIES_LG2 9 124 #define time_before(x, y) ((x) < (y)) 125 #endif 126 127 static inline const struct raid6_recov_calls *raid6_choose_recov(void) 128 { 129 const struct raid6_recov_calls *const *algo; 130 const struct raid6_recov_calls *best; 131 132 for (best = NULL, algo = raid6_recov_algos; *algo; algo++) 133 if (!best || (*algo)->priority > best->priority) 134 if (!(*algo)->valid || (*algo)->valid()) 135 best = *algo; 136 137 if (best) { 138 raid6_2data_recov = best->data2; 139 raid6_datap_recov = best->datap; 140 141 pr_info("raid6: using %s recovery algorithm\n", best->name); 142 } else 143 pr_err("raid6: Yikes! No recovery algorithm found!\n"); 144 145 return best; 146 } 147 148 static inline const struct raid6_calls *raid6_choose_gen( 149 void *(*const dptrs)[(65536/PAGE_SIZE)+2], const int disks) 150 { 151 unsigned long perf, bestgenperf, bestxorperf, j0, j1; 152 int start = (disks>>1)-1, stop = disks-3; /* work on the second half of the disks */ 153 const struct raid6_calls *const *algo; 154 const struct raid6_calls *best; 155 156 for (bestgenperf = 0, bestxorperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) { 157 if (!best || (*algo)->prefer >= best->prefer) { 158 if ((*algo)->valid && !(*algo)->valid()) 159 continue; 160 161 if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK)) { 162 best = *algo; 163 break; 164 } 165 166 perf = 0; 167 168 preempt_disable(); 169 j0 = jiffies; 170 while ((j1 = jiffies) == j0) 171 cpu_relax(); 172 while (time_before(jiffies, 173 j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { 174 (*algo)->gen_syndrome(disks, PAGE_SIZE, *dptrs); 175 perf++; 176 } 177 preempt_enable(); 178 179 if (perf > bestgenperf) { 180 bestgenperf = perf; 181 best = *algo; 182 } 183 pr_info("raid6: %-8s gen() %5ld MB/s\n", (*algo)->name, 184 (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); 185 186 if (!(*algo)->xor_syndrome) 187 continue; 188 189 perf = 0; 190 191 preempt_disable(); 192 j0 = jiffies; 193 while ((j1 = jiffies) == j0) 194 cpu_relax(); 195 while (time_before(jiffies, 196 j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { 197 (*algo)->xor_syndrome(disks, start, stop, 198 PAGE_SIZE, *dptrs); 199 perf++; 200 } 201 preempt_enable(); 202 203 if (best == *algo) 204 bestxorperf = perf; 205 206 pr_info("raid6: %-8s xor() %5ld MB/s\n", (*algo)->name, 207 (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2+1)); 208 } 209 } 210 211 if (best) { 212 pr_info("raid6: using algorithm %s gen() %ld MB/s\n", 213 best->name, 214 (bestgenperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2)); 215 if (best->xor_syndrome) 216 pr_info("raid6: .... xor() %ld MB/s, rmw enabled\n", 217 (bestxorperf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2+1)); 218 raid6_call = *best; 219 } else 220 pr_err("raid6: Yikes! No algorithm found!\n"); 221 222 return best; 223 } 224 225 226 /* Try to pick the best algorithm */ 227 /* This code uses the gfmul table as convenient data set to abuse */ 228 229 int __init raid6_select_algo(void) 230 { 231 const int disks = (65536/PAGE_SIZE)+2; 232 233 const struct raid6_calls *gen_best; 234 const struct raid6_recov_calls *rec_best; 235 char *syndromes; 236 void *dptrs[(65536/PAGE_SIZE)+2]; 237 int i; 238 239 for (i = 0; i < disks-2; i++) 240 dptrs[i] = ((char *)raid6_gfmul) + PAGE_SIZE*i; 241 242 /* Normal code - use a 2-page allocation to avoid D$ conflict */ 243 syndromes = (void *) __get_free_pages(GFP_KERNEL, 1); 244 245 if (!syndromes) { 246 pr_err("raid6: Yikes! No memory available.\n"); 247 return -ENOMEM; 248 } 249 250 dptrs[disks-2] = syndromes; 251 dptrs[disks-1] = syndromes + PAGE_SIZE; 252 253 /* select raid gen_syndrome function */ 254 gen_best = raid6_choose_gen(&dptrs, disks); 255 256 /* select raid recover functions */ 257 rec_best = raid6_choose_recov(); 258 259 free_pages((unsigned long)syndromes, 1); 260 261 return gen_best && rec_best ? 0 : -EINVAL; 262 } 263 264 static void raid6_exit(void) 265 { 266 do { } while (0); 267 } 268 269 subsys_initcall(raid6_select_algo); 270 module_exit(raid6_exit); 271 MODULE_LICENSE("GPL"); 272 MODULE_DESCRIPTION("RAID6 Q-syndrome calculations"); 273