1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2021 Maciej W. Rozycki 4 */ 5 6 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 7 8 #include <linux/init.h> 9 #include <linux/ktime.h> 10 #include <linux/module.h> 11 #include <linux/printk.h> 12 #include <linux/time64.h> 13 #include <linux/types.h> 14 15 #include <asm/div64.h> 16 17 #define TEST_DIV64_N_ITER 1024 18 19 static const u64 test_div64_dividends[] = { 20 0x00000000ab275080, 21 0x0000000fe73c1959, 22 0x000000e54c0a74b1, 23 0x00000d4398ff1ef9, 24 0x0000a18c2ee1c097, 25 0x00079fb80b072e4a, 26 0x0072db27380dd689, 27 0x0842f488162e2284, 28 0xf66745411d8ab063, 29 }; 30 #define SIZE_DIV64_DIVIDENDS ARRAY_SIZE(test_div64_dividends) 31 32 #define TEST_DIV64_DIVISOR_0 0x00000009 33 #define TEST_DIV64_DIVISOR_1 0x0000007c 34 #define TEST_DIV64_DIVISOR_2 0x00000204 35 #define TEST_DIV64_DIVISOR_3 0x0000cb5b 36 #define TEST_DIV64_DIVISOR_4 0x00010000 37 #define TEST_DIV64_DIVISOR_5 0x0008a880 38 #define TEST_DIV64_DIVISOR_6 0x003fd3ae 39 #define TEST_DIV64_DIVISOR_7 0x0b658fac 40 #define TEST_DIV64_DIVISOR_8 0xdc08b349 41 42 static const u32 test_div64_divisors[] = { 43 TEST_DIV64_DIVISOR_0, 44 TEST_DIV64_DIVISOR_1, 45 TEST_DIV64_DIVISOR_2, 46 TEST_DIV64_DIVISOR_3, 47 TEST_DIV64_DIVISOR_4, 48 TEST_DIV64_DIVISOR_5, 49 TEST_DIV64_DIVISOR_6, 50 TEST_DIV64_DIVISOR_7, 51 TEST_DIV64_DIVISOR_8, 52 }; 53 #define SIZE_DIV64_DIVISORS ARRAY_SIZE(test_div64_divisors) 54 55 static const struct { 56 u64 quotient; 57 u32 remainder; 58 } test_div64_results[SIZE_DIV64_DIVISORS][SIZE_DIV64_DIVIDENDS] = { 59 { 60 { 0x0000000013045e47, 0x00000001 }, 61 { 0x000000000161596c, 0x00000030 }, 62 { 0x000000000054e9d4, 0x00000130 }, 63 { 0x000000000000d776, 0x0000278e }, 64 { 0x000000000000ab27, 0x00005080 }, 65 { 0x00000000000013c4, 0x0004ce80 }, 66 { 0x00000000000002ae, 0x001e143c }, 67 { 0x000000000000000f, 0x0033e56c }, 68 { 0x0000000000000000, 0xab275080 }, 69 }, { 70 { 0x00000001c45c02d1, 0x00000000 }, 71 { 0x0000000020d5213c, 0x00000049 }, 72 { 0x0000000007e3d65f, 0x000001dd }, 73 { 0x0000000000140531, 0x000065ee }, 74 { 0x00000000000fe73c, 0x00001959 }, 75 { 0x000000000001d637, 0x0004e5d9 }, 76 { 0x0000000000003fc9, 0x000713bb }, 77 { 0x0000000000000165, 0x029abe7d }, 78 { 0x0000000000000012, 0x6e9f7e37 }, 79 }, { 80 { 0x000000197a3a0cf7, 0x00000002 }, 81 { 0x00000001d9632e5c, 0x00000021 }, 82 { 0x0000000071c28039, 0x000001cd }, 83 { 0x000000000120a844, 0x0000b885 }, 84 { 0x0000000000e54c0a, 0x000074b1 }, 85 { 0x00000000001a7bb3, 0x00072331 }, 86 { 0x00000000000397ad, 0x0002c61b }, 87 { 0x000000000000141e, 0x06ea2e89 }, 88 { 0x000000000000010a, 0xab002ad7 }, 89 }, { 90 { 0x0000017949e37538, 0x00000001 }, 91 { 0x0000001b62441f37, 0x00000055 }, 92 { 0x0000000694a3391d, 0x00000085 }, 93 { 0x0000000010b2a5d2, 0x0000a753 }, 94 { 0x000000000d4398ff, 0x00001ef9 }, 95 { 0x0000000001882ec6, 0x0005cbf9 }, 96 { 0x000000000035333b, 0x0017abdf }, 97 { 0x00000000000129f1, 0x0ab4520d }, 98 { 0x0000000000000f6e, 0x8ac0ce9b }, 99 }, { 100 { 0x000011f321a74e49, 0x00000006 }, 101 { 0x0000014d8481d211, 0x0000005b }, 102 { 0x0000005025cbd92d, 0x000001e3 }, 103 { 0x00000000cb5e71e3, 0x000043e6 }, 104 { 0x00000000a18c2ee1, 0x0000c097 }, 105 { 0x0000000012a88828, 0x00036c97 }, 106 { 0x000000000287f16f, 0x002c2a25 }, 107 { 0x00000000000e2cc7, 0x02d581e3 }, 108 { 0x000000000000bbf4, 0x1ba08c03 }, 109 }, { 110 { 0x0000d8db8f72935d, 0x00000005 }, 111 { 0x00000fbd5aed7a2e, 0x00000002 }, 112 { 0x000003c84b6ea64a, 0x00000122 }, 113 { 0x0000000998fa8829, 0x000044b7 }, 114 { 0x000000079fb80b07, 0x00002e4a }, 115 { 0x00000000e16b20fa, 0x0002a14a }, 116 { 0x000000001e940d22, 0x00353b2e }, 117 { 0x0000000000ab40ac, 0x06fba6ba }, 118 { 0x000000000008debd, 0x72d98365 }, 119 }, { 120 { 0x000cc3045b8fc281, 0x00000000 }, 121 { 0x0000ed1f48b5c9fc, 0x00000079 }, 122 { 0x000038fb9c63406a, 0x000000e1 }, 123 { 0x000000909705b825, 0x00000a62 }, 124 { 0x00000072db27380d, 0x0000d689 }, 125 { 0x0000000d43fce827, 0x00082b09 }, 126 { 0x00000001ccaba11a, 0x0037e8dd }, 127 { 0x000000000a13f729, 0x0566dffd }, 128 { 0x000000000085a14b, 0x23d36726 }, 129 }, { 130 { 0x00eafeb9c993592b, 0x00000001 }, 131 { 0x00110e5befa9a991, 0x00000048 }, 132 { 0x00041947b4a1d36a, 0x000000dc }, 133 { 0x00000a6679327311, 0x0000c079 }, 134 { 0x00000842f488162e, 0x00002284 }, 135 { 0x000000f4459740fc, 0x00084484 }, 136 { 0x0000002122c47bf9, 0x002ca446 }, 137 { 0x00000000b9936290, 0x004979c4 }, 138 { 0x00000000099ca89d, 0x9db446bf }, 139 }, { 140 { 0x1b60cece589da1d2, 0x00000001 }, 141 { 0x01fcb42be1453f5b, 0x0000004f }, 142 { 0x007a3f2457df0749, 0x0000013f }, 143 { 0x0001363130e3ec7b, 0x000017aa }, 144 { 0x0000f66745411d8a, 0x0000b063 }, 145 { 0x00001c757dfab350, 0x00048863 }, 146 { 0x000003dc4979c652, 0x00224ea7 }, 147 { 0x000000159edc3144, 0x06409ab3 }, 148 { 0x000000011eadfee3, 0xa99c48a8 }, 149 }, 150 }; 151 152 static inline bool test_div64_verify(u64 quotient, u32 remainder, int i, int j) 153 { 154 return (quotient == test_div64_results[i][j].quotient && 155 remainder == test_div64_results[i][j].remainder); 156 } 157 158 /* 159 * This needs to be a macro, because we don't want to rely on the compiler 160 * to do constant propagation, and `do_div' may take a different path for 161 * constants, so we do want to verify that as well. 162 */ 163 #define test_div64_one(dividend, divisor, i, j) ({ \ 164 bool result = true; \ 165 u64 quotient; \ 166 u32 remainder; \ 167 \ 168 quotient = dividend; \ 169 remainder = do_div(quotient, divisor); \ 170 if (!test_div64_verify(quotient, remainder, i, j)) { \ 171 pr_err("ERROR: %016llx / %08x => %016llx,%08x\n", \ 172 dividend, divisor, quotient, remainder); \ 173 pr_err("ERROR: expected value => %016llx,%08x\n",\ 174 test_div64_results[i][j].quotient, \ 175 test_div64_results[i][j].remainder); \ 176 result = false; \ 177 } \ 178 result; \ 179 }) 180 181 /* 182 * Run calculation for the same divisor value expressed as a constant 183 * and as a variable, so as to verify the implementation for both cases 184 * should they be handled by different code execution paths. 185 */ 186 static bool __init test_div64(void) 187 { 188 u64 dividend; 189 int i, j; 190 191 for (i = 0; i < SIZE_DIV64_DIVIDENDS; i++) { 192 dividend = test_div64_dividends[i]; 193 if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_0, i, 0)) 194 return false; 195 if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_1, i, 1)) 196 return false; 197 if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_2, i, 2)) 198 return false; 199 if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_3, i, 3)) 200 return false; 201 if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_4, i, 4)) 202 return false; 203 if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_5, i, 5)) 204 return false; 205 if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_6, i, 6)) 206 return false; 207 if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_7, i, 7)) 208 return false; 209 if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_8, i, 8)) 210 return false; 211 for (j = 0; j < SIZE_DIV64_DIVISORS; j++) { 212 if (!test_div64_one(dividend, test_div64_divisors[j], 213 i, j)) 214 return false; 215 } 216 } 217 return true; 218 } 219 220 static int __init test_div64_init(void) 221 { 222 struct timespec64 ts, ts0, ts1; 223 int i; 224 225 pr_info("Starting 64bit/32bit division and modulo test\n"); 226 ktime_get_ts64(&ts0); 227 228 for (i = 0; i < TEST_DIV64_N_ITER; i++) 229 if (!test_div64()) 230 break; 231 232 ktime_get_ts64(&ts1); 233 ts = timespec64_sub(ts1, ts0); 234 pr_info("Completed 64bit/32bit division and modulo test, " 235 "%llu.%09lus elapsed\n", ts.tv_sec, ts.tv_nsec); 236 237 return 0; 238 } 239 240 static void __exit test_div64_exit(void) 241 { 242 } 243 244 module_init(test_div64_init); 245 module_exit(test_div64_exit); 246 247 MODULE_AUTHOR("Maciej W. Rozycki <macro@orcam.me.uk>"); 248 MODULE_LICENSE("GPL"); 249 MODULE_DESCRIPTION("64bit/32bit division and modulo test module"); 250