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 &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, 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, best = NULL, algo = raid6_algos; *algo; algo++) { 160 if (!best || (*algo)->priority >= best->priority) { 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 } 191 192 if (!best) { 193 pr_err("raid6: Yikes! No algorithm found!\n"); 194 goto out; 195 } 196 197 raid6_call = *best; 198 199 if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK)) { 200 pr_info("raid6: skipped pq benchmark and selected %s\n", 201 best->name); 202 goto out; 203 } 204 205 pr_info("raid6: using algorithm %s gen() %ld MB/s\n", 206 best->name, 207 (bestgenperf * HZ * (disks - 2)) >> 208 (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2)); 209 210 if (best->xor_syndrome) { 211 perf = 0; 212 213 preempt_disable(); 214 j0 = jiffies; 215 while ((j1 = jiffies) == j0) 216 cpu_relax(); 217 while (time_before(jiffies, 218 j1 + (1 << RAID6_TIME_JIFFIES_LG2))) { 219 best->xor_syndrome(disks, start, stop, 220 PAGE_SIZE, *dptrs); 221 perf++; 222 } 223 preempt_enable(); 224 225 pr_info("raid6: .... xor() %ld MB/s, rmw enabled\n", 226 (perf * HZ * (disks - 2)) >> 227 (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2 + 1)); 228 } 229 230 out: 231 return best; 232 } 233 234 235 /* Try to pick the best algorithm */ 236 /* This code uses the gfmul table as convenient data set to abuse */ 237 238 int __init raid6_select_algo(void) 239 { 240 const int disks = RAID6_TEST_DISKS; 241 242 const struct raid6_calls *gen_best; 243 const struct raid6_recov_calls *rec_best; 244 char *disk_ptr, *p; 245 void *dptrs[RAID6_TEST_DISKS]; 246 int i, cycle; 247 248 /* prepare the buffer and fill it circularly with gfmul table */ 249 disk_ptr = (char *)__get_free_pages(GFP_KERNEL, RAID6_TEST_DISKS_ORDER); 250 if (!disk_ptr) { 251 pr_err("raid6: Yikes! No memory available.\n"); 252 return -ENOMEM; 253 } 254 255 p = disk_ptr; 256 for (i = 0; i < disks; i++) 257 dptrs[i] = p + PAGE_SIZE * i; 258 259 cycle = ((disks - 2) * PAGE_SIZE) / 65536; 260 for (i = 0; i < cycle; i++) { 261 memcpy(p, raid6_gfmul, 65536); 262 p += 65536; 263 } 264 265 if ((disks - 2) * PAGE_SIZE % 65536) 266 memcpy(p, raid6_gfmul, (disks - 2) * PAGE_SIZE % 65536); 267 268 /* select raid gen_syndrome function */ 269 gen_best = raid6_choose_gen(&dptrs, disks); 270 271 /* select raid recover functions */ 272 rec_best = raid6_choose_recov(); 273 274 free_pages((unsigned long)disk_ptr, RAID6_TEST_DISKS_ORDER); 275 276 return gen_best && rec_best ? 0 : -EINVAL; 277 } 278 279 static void raid6_exit(void) 280 { 281 do { } while (0); 282 } 283 284 subsys_initcall(raid6_select_algo); 285 module_exit(raid6_exit); 286 MODULE_LICENSE("GPL"); 287 MODULE_DESCRIPTION("RAID6 Q-syndrome calculations"); 288