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 #define RAID6_TEST_DISKS 8 128 #define RAID6_TEST_DISKS_ORDER 3 129 130 static inline const struct raid6_recov_calls *raid6_choose_recov(void) 131 { 132 const struct raid6_recov_calls *const *algo; 133 const struct raid6_recov_calls *best; 134 135 for (best = NULL, algo = raid6_recov_algos; *algo; algo++) 136 if (!best || (*algo)->priority > best->priority) 137 if (!(*algo)->valid || (*algo)->valid()) 138 best = *algo; 139 140 if (best) { 141 raid6_2data_recov = best->data2; 142 raid6_datap_recov = best->datap; 143 144 pr_info("raid6: using %s recovery algorithm\n", best->name); 145 } else 146 pr_err("raid6: Yikes! No recovery algorithm found!\n"); 147 148 return best; 149 } 150 151 static inline const struct raid6_calls *raid6_choose_gen( 152 void *(*const dptrs)[RAID6_TEST_DISKS], const int disks) 153 { 154 unsigned long perf, bestgenperf, bestxorperf, j0, j1; 155 int start = (disks>>1)-1, stop = disks-3; /* work on the second half of the disks */ 156 const struct raid6_calls *const *algo; 157 const struct raid6_calls *best; 158 159 for (bestgenperf = 0, bestxorperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) { 160 if (!best || (*algo)->prefer >= best->prefer) { 161 if ((*algo)->valid && !(*algo)->valid()) 162 continue; 163 164 if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK)) { 165 best = *algo; 166 break; 167 } 168 169 perf = 0; 170 171 preempt_disable(); 172 j0 = jiffies; 173 while ((j1 = jiffies) == j0) 174 cpu_relax(); 175 while (time_before(jiffies, 176 j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { 177 (*algo)->gen_syndrome(disks, PAGE_SIZE, *dptrs); 178 perf++; 179 } 180 preempt_enable(); 181 182 if (perf > bestgenperf) { 183 bestgenperf = perf; 184 best = *algo; 185 } 186 pr_info("raid6: %-8s gen() %5ld MB/s\n", (*algo)->name, 187 (perf * HZ * (disks-2)) >> 188 (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2)); 189 190 if (!(*algo)->xor_syndrome) 191 continue; 192 193 perf = 0; 194 195 preempt_disable(); 196 j0 = jiffies; 197 while ((j1 = jiffies) == j0) 198 cpu_relax(); 199 while (time_before(jiffies, 200 j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { 201 (*algo)->xor_syndrome(disks, start, stop, 202 PAGE_SIZE, *dptrs); 203 perf++; 204 } 205 preempt_enable(); 206 207 if (best == *algo) 208 bestxorperf = perf; 209 210 pr_info("raid6: %-8s xor() %5ld MB/s\n", (*algo)->name, 211 (perf * HZ * (disks-2)) >> 212 (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2 + 1)); 213 } 214 } 215 216 if (best) { 217 if (IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK)) { 218 pr_info("raid6: using algorithm %s gen() %ld MB/s\n", 219 best->name, 220 (bestgenperf * HZ * (disks-2)) >> 221 (20 - PAGE_SHIFT+RAID6_TIME_JIFFIES_LG2)); 222 if (best->xor_syndrome) 223 pr_info("raid6: .... xor() %ld MB/s, rmw enabled\n", 224 (bestxorperf * HZ * (disks-2)) >> 225 (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2 + 1)); 226 } else 227 pr_info("raid6: skip pq benchmark and using algorithm %s\n", 228 best->name); 229 raid6_call = *best; 230 } else 231 pr_err("raid6: Yikes! No algorithm found!\n"); 232 233 return best; 234 } 235 236 237 /* Try to pick the best algorithm */ 238 /* This code uses the gfmul table as convenient data set to abuse */ 239 240 int __init raid6_select_algo(void) 241 { 242 const int disks = RAID6_TEST_DISKS; 243 244 const struct raid6_calls *gen_best; 245 const struct raid6_recov_calls *rec_best; 246 char *disk_ptr, *p; 247 void *dptrs[RAID6_TEST_DISKS]; 248 int i, cycle; 249 250 /* prepare the buffer and fill it circularly with gfmul table */ 251 disk_ptr = (char *)__get_free_pages(GFP_KERNEL, RAID6_TEST_DISKS_ORDER); 252 if (!disk_ptr) { 253 pr_err("raid6: Yikes! No memory available.\n"); 254 return -ENOMEM; 255 } 256 257 p = disk_ptr; 258 for (i = 0; i < disks; i++) 259 dptrs[i] = p + PAGE_SIZE * i; 260 261 cycle = ((disks - 2) * PAGE_SIZE) / 65536; 262 for (i = 0; i < cycle; i++) { 263 memcpy(p, raid6_gfmul, 65536); 264 p += 65536; 265 } 266 267 if ((disks - 2) * PAGE_SIZE % 65536) 268 memcpy(p, raid6_gfmul, (disks - 2) * PAGE_SIZE % 65536); 269 270 /* select raid gen_syndrome function */ 271 gen_best = raid6_choose_gen(&dptrs, disks); 272 273 /* select raid recover functions */ 274 rec_best = raid6_choose_recov(); 275 276 free_pages((unsigned long)disk_ptr, RAID6_TEST_DISKS_ORDER); 277 278 return gen_best && rec_best ? 0 : -EINVAL; 279 } 280 281 static void raid6_exit(void) 282 { 283 do { } while (0); 284 } 285 286 subsys_initcall(raid6_select_algo); 287 module_exit(raid6_exit); 288 MODULE_LICENSE("GPL"); 289 MODULE_DESCRIPTION("RAID6 Q-syndrome calculations"); 290