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 */ 22 const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256))); 23 EXPORT_SYMBOL(raid6_empty_zero_page); 24 #endif 25 26 struct raid6_calls raid6_call; 27 EXPORT_SYMBOL_GPL(raid6_call); 28 29 const 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 #if defined(__ia64__) 85 &raid6_intx32, 86 &raid6_intx16, 87 #endif 88 &raid6_intx8, 89 &raid6_intx4, 90 &raid6_intx2, 91 &raid6_intx1, 92 NULL 93 }; 94 95 void (*raid6_2data_recov)(int, size_t, int, int, void **); 96 EXPORT_SYMBOL_GPL(raid6_2data_recov); 97 98 void (*raid6_datap_recov)(int, size_t, int, void **); 99 EXPORT_SYMBOL_GPL(raid6_datap_recov); 100 101 const struct raid6_recov_calls *const raid6_recov_algos[] = { 102 #ifdef CONFIG_X86 103 #ifdef CONFIG_AS_AVX512 104 &raid6_recov_avx512, 105 #endif 106 &raid6_recov_avx2, 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 #ifdef CONFIG_LOONGARCH 116 #ifdef CONFIG_CPU_HAS_LASX 117 &raid6_recov_lasx, 118 #endif 119 #ifdef CONFIG_CPU_HAS_LSX 120 &raid6_recov_lsx, 121 #endif 122 #endif 123 &raid6_recov_intx1, 124 NULL 125 }; 126 127 #ifdef __KERNEL__ 128 #define RAID6_TIME_JIFFIES_LG2 4 129 #else 130 /* Need more time to be stable in userspace */ 131 #define RAID6_TIME_JIFFIES_LG2 9 132 #define time_before(x, y) ((x) < (y)) 133 #endif 134 135 #define RAID6_TEST_DISKS 8 136 #define RAID6_TEST_DISKS_ORDER 3 137 138 static inline const struct raid6_recov_calls *raid6_choose_recov(void) 139 { 140 const struct raid6_recov_calls *const *algo; 141 const struct raid6_recov_calls *best; 142 143 for (best = NULL, algo = raid6_recov_algos; *algo; algo++) 144 if (!best || (*algo)->priority > best->priority) 145 if (!(*algo)->valid || (*algo)->valid()) 146 best = *algo; 147 148 if (best) { 149 raid6_2data_recov = best->data2; 150 raid6_datap_recov = best->datap; 151 152 pr_info("raid6: using %s recovery algorithm\n", best->name); 153 } else 154 pr_err("raid6: Yikes! No recovery algorithm found!\n"); 155 156 return best; 157 } 158 159 static inline const struct raid6_calls *raid6_choose_gen( 160 void *(*const dptrs)[RAID6_TEST_DISKS], const int disks) 161 { 162 unsigned long perf, bestgenperf, j0, j1; 163 int start = (disks>>1)-1, stop = disks-3; /* work on the second half of the disks */ 164 const struct raid6_calls *const *algo; 165 const struct raid6_calls *best; 166 167 for (bestgenperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) { 168 if (!best || (*algo)->priority >= best->priority) { 169 if ((*algo)->valid && !(*algo)->valid()) 170 continue; 171 172 if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK)) { 173 best = *algo; 174 break; 175 } 176 177 perf = 0; 178 179 preempt_disable(); 180 j0 = jiffies; 181 while ((j1 = jiffies) == j0) 182 cpu_relax(); 183 while (time_before(jiffies, 184 j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { 185 (*algo)->gen_syndrome(disks, PAGE_SIZE, *dptrs); 186 perf++; 187 } 188 preempt_enable(); 189 190 if (perf > bestgenperf) { 191 bestgenperf = perf; 192 best = *algo; 193 } 194 pr_info("raid6: %-8s gen() %5ld MB/s\n", (*algo)->name, 195 (perf * HZ * (disks-2)) >> 196 (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2)); 197 } 198 } 199 200 if (!best) { 201 pr_err("raid6: Yikes! No algorithm found!\n"); 202 goto out; 203 } 204 205 raid6_call = *best; 206 207 if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK)) { 208 pr_info("raid6: skipped pq benchmark and selected %s\n", 209 best->name); 210 goto out; 211 } 212 213 pr_info("raid6: using algorithm %s gen() %ld MB/s\n", 214 best->name, 215 (bestgenperf * HZ * (disks - 2)) >> 216 (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2)); 217 218 if (best->xor_syndrome) { 219 perf = 0; 220 221 preempt_disable(); 222 j0 = jiffies; 223 while ((j1 = jiffies) == j0) 224 cpu_relax(); 225 while (time_before(jiffies, 226 j1 + (1 << RAID6_TIME_JIFFIES_LG2))) { 227 best->xor_syndrome(disks, start, stop, 228 PAGE_SIZE, *dptrs); 229 perf++; 230 } 231 preempt_enable(); 232 233 pr_info("raid6: .... xor() %ld MB/s, rmw enabled\n", 234 (perf * HZ * (disks - 2)) >> 235 (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2 + 1)); 236 } 237 238 out: 239 return best; 240 } 241 242 243 /* Try to pick the best algorithm */ 244 /* This code uses the gfmul table as convenient data set to abuse */ 245 246 int __init raid6_select_algo(void) 247 { 248 const int disks = RAID6_TEST_DISKS; 249 250 const struct raid6_calls *gen_best; 251 const struct raid6_recov_calls *rec_best; 252 char *disk_ptr, *p; 253 void *dptrs[RAID6_TEST_DISKS]; 254 int i, cycle; 255 256 /* prepare the buffer and fill it circularly with gfmul table */ 257 disk_ptr = (char *)__get_free_pages(GFP_KERNEL, RAID6_TEST_DISKS_ORDER); 258 if (!disk_ptr) { 259 pr_err("raid6: Yikes! No memory available.\n"); 260 return -ENOMEM; 261 } 262 263 p = disk_ptr; 264 for (i = 0; i < disks; i++) 265 dptrs[i] = p + PAGE_SIZE * i; 266 267 cycle = ((disks - 2) * PAGE_SIZE) / 65536; 268 for (i = 0; i < cycle; i++) { 269 memcpy(p, raid6_gfmul, 65536); 270 p += 65536; 271 } 272 273 if ((disks - 2) * PAGE_SIZE % 65536) 274 memcpy(p, raid6_gfmul, (disks - 2) * PAGE_SIZE % 65536); 275 276 /* select raid gen_syndrome function */ 277 gen_best = raid6_choose_gen(&dptrs, disks); 278 279 /* select raid recover functions */ 280 rec_best = raid6_choose_recov(); 281 282 free_pages((unsigned long)disk_ptr, RAID6_TEST_DISKS_ORDER); 283 284 return gen_best && rec_best ? 0 : -EINVAL; 285 } 286 287 static void raid6_exit(void) 288 { 289 do { } while (0); 290 } 291 292 subsys_initcall(raid6_select_algo); 293 module_exit(raid6_exit); 294 MODULE_LICENSE("GPL"); 295 MODULE_DESCRIPTION("RAID6 Q-syndrome calculations"); 296