1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2024 BayLibre SAS 4 */ 5 6 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 7 8 #include <linux/init.h> 9 #include <linux/module.h> 10 #include <linux/printk.h> 11 #include <linux/math64.h> 12 13 typedef struct { u64 a; u64 b; u64 c; u64 result; } test_params; 14 15 static test_params test_values[] = { 16 /* this contains many edge values followed by a couple random values */ 17 { 0xb, 0x7, 0x3, 0x19 }, 18 { 0xffff0000, 0xffff0000, 0xf, 0x1110eeef00000000 }, 19 { 0xffffffff, 0xffffffff, 0x1, 0xfffffffe00000001 }, 20 { 0xffffffff, 0xffffffff, 0x2, 0x7fffffff00000000 }, 21 { 0x1ffffffff, 0xffffffff, 0x2, 0xfffffffe80000000 }, 22 { 0x1ffffffff, 0xffffffff, 0x3, 0xaaaaaaa9aaaaaaab }, 23 { 0x1ffffffff, 0x1ffffffff, 0x4, 0xffffffff00000000 }, 24 { 0xffff000000000000, 0xffff000000000000, 0xffff000000000001, 0xfffeffffffffffff }, 25 { 0x3333333333333333, 0x3333333333333333, 0x5555555555555555, 0x1eb851eb851eb851 }, 26 { 0x7fffffffffffffff, 0x2, 0x3, 0x5555555555555554 }, 27 { 0xffffffffffffffff, 0x2, 0x8000000000000000, 0x3 }, 28 { 0xffffffffffffffff, 0x2, 0xc000000000000000, 0x2 }, 29 { 0xffffffffffffffff, 0x4000000000000004, 0x8000000000000000, 0x8000000000000007 }, 30 { 0xffffffffffffffff, 0x4000000000000001, 0x8000000000000000, 0x8000000000000001 }, 31 { 0xffffffffffffffff, 0x8000000000000001, 0xffffffffffffffff, 0x8000000000000001 }, 32 { 0xfffffffffffffffe, 0x8000000000000001, 0xffffffffffffffff, 0x8000000000000000 }, 33 { 0xffffffffffffffff, 0x8000000000000001, 0xfffffffffffffffe, 0x8000000000000001 }, 34 { 0xffffffffffffffff, 0x8000000000000001, 0xfffffffffffffffd, 0x8000000000000002 }, 35 { 0x7fffffffffffffff, 0xffffffffffffffff, 0xc000000000000000, 0xaaaaaaaaaaaaaaa8 }, 36 { 0xffffffffffffffff, 0x7fffffffffffffff, 0xa000000000000000, 0xccccccccccccccca }, 37 { 0xffffffffffffffff, 0x7fffffffffffffff, 0x9000000000000000, 0xe38e38e38e38e38b }, 38 { 0x7fffffffffffffff, 0x7fffffffffffffff, 0x5000000000000000, 0xccccccccccccccc9 }, 39 { 0xffffffffffffffff, 0xfffffffffffffffe, 0xffffffffffffffff, 0xfffffffffffffffe }, 40 { 0xe6102d256d7ea3ae, 0x70a77d0be4c31201, 0xd63ec35ab3220357, 0x78f8bf8cc86c6e18 }, 41 { 0xf53bae05cb86c6e1, 0x3847b32d2f8d32e0, 0xcfd4f55a647f403c, 0x42687f79d8998d35 }, 42 { 0x9951c5498f941092, 0x1f8c8bfdf287a251, 0xa3c8dc5f81ea3fe2, 0x1d887cb25900091f }, 43 { 0x374fee9daa1bb2bb, 0x0d0bfbff7b8ae3ef, 0xc169337bd42d5179, 0x03bb2dbaffcbb961 }, 44 { 0xeac0d03ac10eeaf0, 0x89be05dfa162ed9b, 0x92bb1679a41f0e4b, 0xdc5f5cc9e270d216 }, 45 }; 46 47 /* 48 * The above table can be verified with the following shell script: 49 * 50 * #!/bin/sh 51 * sed -ne 's/^{ \+\(.*\), \+\(.*\), \+\(.*\), \+\(.*\) },$/\1 \2 \3 \4/p' \ 52 * lib/math/test_mul_u64_u64_div_u64.c | 53 * while read a b c r; do 54 * expected=$( printf "obase=16; ibase=16; %X * %X / %X\n" $a $b $c | bc ) 55 * given=$( printf "%X\n" $r ) 56 * if [ "$expected" = "$given" ]; then 57 * echo "$a * $b / $c = $r OK" 58 * else 59 * echo "$a * $b / $c = $r is wrong" >&2 60 * echo "should be equivalent to 0x$expected" >&2 61 * exit 1 62 * fi 63 * done 64 */ 65 66 static int __init test_init(void) 67 { 68 int i; 69 70 pr_info("Starting mul_u64_u64_div_u64() test\n"); 71 72 for (i = 0; i < ARRAY_SIZE(test_values); i++) { 73 u64 a = test_values[i].a; 74 u64 b = test_values[i].b; 75 u64 c = test_values[i].c; 76 u64 expected_result = test_values[i].result; 77 u64 result = mul_u64_u64_div_u64(a, b, c); 78 79 if (result != expected_result) { 80 pr_err("ERROR: 0x%016llx * 0x%016llx / 0x%016llx\n", a, b, c); 81 pr_err("ERROR: expected result: %016llx\n", expected_result); 82 pr_err("ERROR: obtained result: %016llx\n", result); 83 } 84 } 85 86 pr_info("Completed mul_u64_u64_div_u64() test\n"); 87 return 0; 88 } 89 90 static void __exit test_exit(void) 91 { 92 } 93 94 module_init(test_init); 95 module_exit(test_exit); 96 97 MODULE_AUTHOR("Nicolas Pitre"); 98 MODULE_LICENSE("GPL"); 99 MODULE_DESCRIPTION("mul_u64_u64_div_u64() test module"); 100