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 &raid6_avx512x2, 32 &raid6_avx512x1, 33 &raid6_avx2x2, 34 &raid6_avx2x1, 35 &raid6_sse2x2, 36 &raid6_sse2x1, 37 &raid6_sse1x2, 38 &raid6_sse1x1, 39 &raid6_mmxx2, 40 &raid6_mmxx1, 41 #endif 42 #if defined(__x86_64__) && !defined(__arch_um__) 43 &raid6_avx512x4, 44 &raid6_avx512x2, 45 &raid6_avx512x1, 46 &raid6_avx2x4, 47 &raid6_avx2x2, 48 &raid6_avx2x1, 49 &raid6_sse2x4, 50 &raid6_sse2x2, 51 &raid6_sse2x1, 52 #endif 53 #ifdef CONFIG_ALTIVEC 54 &raid6_vpermxor8, 55 &raid6_vpermxor4, 56 &raid6_vpermxor2, 57 &raid6_vpermxor1, 58 &raid6_altivec8, 59 &raid6_altivec4, 60 &raid6_altivec2, 61 &raid6_altivec1, 62 #endif 63 #if defined(CONFIG_S390) 64 &raid6_s390vx8, 65 #endif 66 #ifdef CONFIG_KERNEL_MODE_NEON 67 &raid6_neonx8, 68 &raid6_neonx4, 69 &raid6_neonx2, 70 &raid6_neonx1, 71 #endif 72 #ifdef CONFIG_LOONGARCH 73 #ifdef CONFIG_CPU_HAS_LASX 74 &raid6_lasx, 75 #endif 76 #ifdef CONFIG_CPU_HAS_LSX 77 &raid6_lsx, 78 #endif 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 &raid6_recov_avx512, 96 &raid6_recov_avx2, 97 &raid6_recov_ssse3, 98 #endif 99 #ifdef CONFIG_S390 100 &raid6_recov_s390xc, 101 #endif 102 #if defined(CONFIG_KERNEL_MODE_NEON) 103 &raid6_recov_neon, 104 #endif 105 #ifdef CONFIG_LOONGARCH 106 #ifdef CONFIG_CPU_HAS_LASX 107 &raid6_recov_lasx, 108 #endif 109 #ifdef CONFIG_CPU_HAS_LSX 110 &raid6_recov_lsx, 111 #endif 112 #endif 113 &raid6_recov_intx1, 114 NULL 115 }; 116 117 #ifdef __KERNEL__ 118 #define RAID6_TIME_JIFFIES_LG2 4 119 #else 120 /* Need more time to be stable in userspace */ 121 #define RAID6_TIME_JIFFIES_LG2 9 122 #define time_before(x, y) ((x) < (y)) 123 #endif 124 125 #define RAID6_TEST_DISKS 8 126 #define RAID6_TEST_DISKS_ORDER 3 127 128 static inline const struct raid6_recov_calls *raid6_choose_recov(void) 129 { 130 const struct raid6_recov_calls *const *algo; 131 const struct raid6_recov_calls *best; 132 133 for (best = NULL, algo = raid6_recov_algos; *algo; algo++) 134 if (!best || (*algo)->priority > best->priority) 135 if (!(*algo)->valid || (*algo)->valid()) 136 best = *algo; 137 138 if (best) { 139 raid6_2data_recov = best->data2; 140 raid6_datap_recov = best->datap; 141 142 pr_info("raid6: using %s recovery algorithm\n", best->name); 143 } else 144 pr_err("raid6: Yikes! No recovery algorithm found!\n"); 145 146 return best; 147 } 148 149 static inline const struct raid6_calls *raid6_choose_gen( 150 void *(*const dptrs)[RAID6_TEST_DISKS], const int disks) 151 { 152 unsigned long perf, bestgenperf, j0, j1; 153 int start = (disks>>1)-1, stop = disks-3; /* work on the second half of the disks */ 154 const struct raid6_calls *const *algo; 155 const struct raid6_calls *best; 156 157 for (bestgenperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) { 158 if (!best || (*algo)->priority >= best->priority) { 159 if ((*algo)->valid && !(*algo)->valid()) 160 continue; 161 162 if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK)) { 163 best = *algo; 164 break; 165 } 166 167 perf = 0; 168 169 preempt_disable(); 170 j0 = jiffies; 171 while ((j1 = jiffies) == j0) 172 cpu_relax(); 173 while (time_before(jiffies, 174 j1 + (1<<RAID6_TIME_JIFFIES_LG2))) { 175 (*algo)->gen_syndrome(disks, PAGE_SIZE, *dptrs); 176 perf++; 177 } 178 preempt_enable(); 179 180 if (perf > bestgenperf) { 181 bestgenperf = perf; 182 best = *algo; 183 } 184 pr_info("raid6: %-8s gen() %5ld MB/s\n", (*algo)->name, 185 (perf * HZ * (disks-2)) >> 186 (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2)); 187 } 188 } 189 190 if (!best) { 191 pr_err("raid6: Yikes! No algorithm found!\n"); 192 goto out; 193 } 194 195 raid6_call = *best; 196 197 if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK)) { 198 pr_info("raid6: skipped pq benchmark and selected %s\n", 199 best->name); 200 goto out; 201 } 202 203 pr_info("raid6: using algorithm %s gen() %ld MB/s\n", 204 best->name, 205 (bestgenperf * HZ * (disks - 2)) >> 206 (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2)); 207 208 if (best->xor_syndrome) { 209 perf = 0; 210 211 preempt_disable(); 212 j0 = jiffies; 213 while ((j1 = jiffies) == j0) 214 cpu_relax(); 215 while (time_before(jiffies, 216 j1 + (1 << RAID6_TIME_JIFFIES_LG2))) { 217 best->xor_syndrome(disks, start, stop, 218 PAGE_SIZE, *dptrs); 219 perf++; 220 } 221 preempt_enable(); 222 223 pr_info("raid6: .... xor() %ld MB/s, rmw enabled\n", 224 (perf * HZ * (disks - 2)) >> 225 (20 - PAGE_SHIFT + RAID6_TIME_JIFFIES_LG2 + 1)); 226 } 227 228 out: 229 return best; 230 } 231 232 233 /* Try to pick the best algorithm */ 234 /* This code uses the gfmul table as convenient data set to abuse */ 235 236 int __init raid6_select_algo(void) 237 { 238 const int disks = RAID6_TEST_DISKS; 239 240 const struct raid6_calls *gen_best; 241 const struct raid6_recov_calls *rec_best; 242 char *disk_ptr, *p; 243 void *dptrs[RAID6_TEST_DISKS]; 244 int i, cycle; 245 246 /* prepare the buffer and fill it circularly with gfmul table */ 247 disk_ptr = (char *)__get_free_pages(GFP_KERNEL, RAID6_TEST_DISKS_ORDER); 248 if (!disk_ptr) { 249 pr_err("raid6: Yikes! No memory available.\n"); 250 return -ENOMEM; 251 } 252 253 p = disk_ptr; 254 for (i = 0; i < disks; i++) 255 dptrs[i] = p + PAGE_SIZE * i; 256 257 cycle = ((disks - 2) * PAGE_SIZE) / 65536; 258 for (i = 0; i < cycle; i++) { 259 memcpy(p, raid6_gfmul, 65536); 260 p += 65536; 261 } 262 263 if ((disks - 2) * PAGE_SIZE % 65536) 264 memcpy(p, raid6_gfmul, (disks - 2) * PAGE_SIZE % 65536); 265 266 /* select raid gen_syndrome function */ 267 gen_best = raid6_choose_gen(&dptrs, disks); 268 269 /* select raid recover functions */ 270 rec_best = raid6_choose_recov(); 271 272 free_pages((unsigned long)disk_ptr, RAID6_TEST_DISKS_ORDER); 273 274 return gen_best && rec_best ? 0 : -EINVAL; 275 } 276 277 static void raid6_exit(void) 278 { 279 do { } while (0); 280 } 281 282 subsys_initcall(raid6_select_algo); 283 module_exit(raid6_exit); 284 MODULE_LICENSE("GPL"); 285 MODULE_DESCRIPTION("RAID6 Q-syndrome calculations"); 286