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