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 &raid6_avx2x2, 38 &raid6_avx2x1, 39 &raid6_sse2x2, 40 &raid6_sse2x1, 41 &raid6_sse1x2, 42 &raid6_sse1x1, 43 &raid6_mmxx2, 44 &raid6_mmxx1, 45 #endif 46 #if defined(__x86_64__) && !defined(__arch_um__) 47 #ifdef CONFIG_AS_AVX512 48 &raid6_avx512x4, 49 &raid6_avx512x2, 50 &raid6_avx512x1, 51 #endif 52 &raid6_avx2x4, 53 &raid6_avx2x2, 54 &raid6_avx2x1, 55 &raid6_sse2x4, 56 &raid6_sse2x2, 57 &raid6_sse2x1, 58 #endif 59 #ifdef CONFIG_ALTIVEC 60 &raid6_vpermxor8, 61 &raid6_vpermxor4, 62 &raid6_vpermxor2, 63 &raid6_vpermxor1, 64 &raid6_altivec8, 65 &raid6_altivec4, 66 &raid6_altivec2, 67 &raid6_altivec1, 68 #endif 69 #if defined(CONFIG_S390) 70 &raid6_s390vx8, 71 #endif 72 #ifdef CONFIG_KERNEL_MODE_NEON 73 &raid6_neonx8, 74 &raid6_neonx4, 75 &raid6_neonx2, 76 &raid6_neonx1, 77 #endif 78 #if defined(__ia64__) 79 &raid6_intx32, 80 &raid6_intx16, 81 #endif 82 &raid6_intx8, 83 &raid6_intx4, 84 &raid6_intx2, 85 &raid6_intx1, 86 NULL 87 }; 88 89 void (*raid6_2data_recov)(int, size_t, int, int, void **); 90 EXPORT_SYMBOL_GPL(raid6_2data_recov); 91 92 void (*raid6_datap_recov)(int, size_t, int, void **); 93 EXPORT_SYMBOL_GPL(raid6_datap_recov); 94 95 const struct raid6_recov_calls *const raid6_recov_algos[] = { 96 #ifdef CONFIG_X86 97 #ifdef CONFIG_AS_AVX512 98 &raid6_recov_avx512, 99 #endif 100 &raid6_recov_avx2, 101 &raid6_recov_ssse3, 102 #endif 103 #ifdef CONFIG_S390 104 &raid6_recov_s390xc, 105 #endif 106 #if defined(CONFIG_KERNEL_MODE_NEON) 107 &raid6_recov_neon, 108 #endif 109 &raid6_recov_intx1, 110 NULL 111 }; 112 113 #ifdef __KERNEL__ 114 #define RAID6_TIME_JIFFIES_LG2 4 115 #else 116 /* Need more time to be stable in userspace */ 117 #define RAID6_TIME_JIFFIES_LG2 9 118 #define time_before(x, y) ((x) < (y)) 119 #endif 120 121 #define RAID6_TEST_DISKS 8 122 #define RAID6_TEST_DISKS_ORDER 3 123 124 static inline const struct raid6_recov_calls *raid6_choose_recov(void) 125 { 126 const struct raid6_recov_calls *const *algo; 127 const struct raid6_recov_calls *best; 128 129 for (best = NULL, algo = raid6_recov_algos; *algo; algo++) 130 if (!best || (*algo)->priority > best->priority) 131 if (!(*algo)->valid || (*algo)->valid()) 132 best = *algo; 133 134 if (best) { 135 raid6_2data_recov = best->data2; 136 raid6_datap_recov = best->datap; 137 138 pr_info("raid6: using %s recovery algorithm\n", best->name); 139 } else 140 pr_err("raid6: Yikes! No recovery algorithm found!\n"); 141 142 return best; 143 } 144 145 static inline const struct raid6_calls *raid6_choose_gen( 146 void *(*const dptrs)[RAID6_TEST_DISKS], const int disks) 147 { 148 unsigned long perf, bestgenperf, bestxorperf, j0, j1; 149 int start = (disks>>1)-1, stop = disks-3; /* work on the second half of the disks */ 150 const struct raid6_calls *const *algo; 151 const struct raid6_calls *best; 152 153 for (bestgenperf = 0, bestxorperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) { 154 if (!best || (*algo)->prefer >= best->prefer) { 155 if ((*algo)->valid && !(*algo)->valid()) 156 continue; 157 158 if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK)) { 159 best = *algo; 160 break; 161 } 162 163 perf = 0; 164 165 preempt_disable(); 166 j0 = jiffies; 167 while ((j1 = jiffies) == j0) 168 cpu_relax(); 169 while (time_before(jiffies, 170 j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { 171 (*algo)->gen_syndrome(disks, PAGE_SIZE, *dptrs); 172 perf++; 173 } 174 preempt_enable(); 175 176 if (perf > bestgenperf) { 177 bestgenperf = perf; 178 best = *algo; 179 } 180 pr_info("raid6: %-8s gen() %5ld MB/s\n", (*algo)->name, 181 (perf * HZ * (disks-2)) >> 182 (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2)); 183 184 if (!(*algo)->xor_syndrome) 185 continue; 186 187 perf = 0; 188 189 preempt_disable(); 190 j0 = jiffies; 191 while ((j1 = jiffies) == j0) 192 cpu_relax(); 193 while (time_before(jiffies, 194 j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { 195 (*algo)->xor_syndrome(disks, start, stop, 196 PAGE_SIZE, *dptrs); 197 perf++; 198 } 199 preempt_enable(); 200 201 if (best == *algo) 202 bestxorperf = perf; 203 204 pr_info("raid6: %-8s xor() %5ld MB/s\n", (*algo)->name, 205 (perf * HZ * (disks-2)) >> 206 (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2 + 1)); 207 } 208 } 209 210 if (best) { 211 if (IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK)) { 212 pr_info("raid6: using algorithm %s gen() %ld MB/s\n", 213 best->name, 214 (bestgenperf * HZ * (disks-2)) >> 215 (20 - PAGE_SHIFT+RAID6_TIME_JIFFIES_LG2)); 216 if (best->xor_syndrome) 217 pr_info("raid6: .... xor() %ld MB/s, rmw enabled\n", 218 (bestxorperf * HZ * (disks-2)) >> 219 (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2 + 1)); 220 } else 221 pr_info("raid6: skip pq benchmark and using algorithm %s\n", 222 best->name); 223 raid6_call = *best; 224 } else 225 pr_err("raid6: Yikes! No algorithm found!\n"); 226 227 return best; 228 } 229 230 231 /* Try to pick the best algorithm */ 232 /* This code uses the gfmul table as convenient data set to abuse */ 233 234 int __init raid6_select_algo(void) 235 { 236 const int disks = RAID6_TEST_DISKS; 237 238 const struct raid6_calls *gen_best; 239 const struct raid6_recov_calls *rec_best; 240 char *disk_ptr, *p; 241 void *dptrs[RAID6_TEST_DISKS]; 242 int i, cycle; 243 244 /* prepare the buffer and fill it circularly with gfmul table */ 245 disk_ptr = (char *)__get_free_pages(GFP_KERNEL, RAID6_TEST_DISKS_ORDER); 246 if (!disk_ptr) { 247 pr_err("raid6: Yikes! No memory available.\n"); 248 return -ENOMEM; 249 } 250 251 p = disk_ptr; 252 for (i = 0; i < disks; i++) 253 dptrs[i] = p + PAGE_SIZE * i; 254 255 cycle = ((disks - 2) * PAGE_SIZE) / 65536; 256 for (i = 0; i < cycle; i++) { 257 memcpy(p, raid6_gfmul, 65536); 258 p += 65536; 259 } 260 261 if ((disks - 2) * PAGE_SIZE % 65536) 262 memcpy(p, raid6_gfmul, (disks - 2) * PAGE_SIZE % 65536); 263 264 /* select raid gen_syndrome function */ 265 gen_best = raid6_choose_gen(&dptrs, disks); 266 267 /* select raid recover functions */ 268 rec_best = raid6_choose_recov(); 269 270 free_pages((unsigned long)disk_ptr, RAID6_TEST_DISKS_ORDER); 271 272 return gen_best && rec_best ? 0 : -EINVAL; 273 } 274 275 static void raid6_exit(void) 276 { 277 do { } while (0); 278 } 279 280 subsys_initcall(raid6_select_algo); 281 module_exit(raid6_exit); 282 MODULE_LICENSE("GPL"); 283 MODULE_DESCRIPTION("RAID6 Q-syndrome calculations"); 284