// SPDX-License-Identifier: GPL-2.0/* * Copyright (C) 2021  Maciej W. Rozycki */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/init.h>#include <linux/ktime.h>#include <linux/module.h>#include <linux/printk.h>#include <linux/time64.h>#include <linux/types.h> #include <asm/div64.h> #define TEST_DIV64_N_ITER 1024 static const u64 test_div64_dividends[] = {	0x00000000ab275080,	0x0000000fe73c1959,	0x000000e54c0a74b1,	0x00000d4398ff1ef9,	0x0000a18c2ee1c097,	0x00079fb80b072e4a,	0x0072db27380dd689,	0x0842f488162e2284,	0xf66745411d8ab063,};#define SIZE_DIV64_DIVIDENDS ARRAY_SIZE(test_div64_dividends) #define TEST_DIV64_DIVISOR_0 0x00000009#define TEST_DIV64_DIVISOR_1 0x0000007c#define TEST_DIV64_DIVISOR_2 0x00000204#define TEST_DIV64_DIVISOR_3 0x0000cb5b#define TEST_DIV64_DIVISOR_4 0x00010000#define TEST_DIV64_DIVISOR_5 0x0008a880#define TEST_DIV64_DIVISOR_6 0x003fd3ae#define TEST_DIV64_DIVISOR_7 0x0b658fac#define TEST_DIV64_DIVISOR_8 0xdc08b349 static const u32 test_div64_divisors[] = {	TEST_DIV64_DIVISOR_0,	TEST_DIV64_DIVISOR_1,	TEST_DIV64_DIVISOR_2,	TEST_DIV64_DIVISOR_3,	TEST_DIV64_DIVISOR_4,	TEST_DIV64_DIVISOR_5,	TEST_DIV64_DIVISOR_6,	TEST_DIV64_DIVISOR_7,	TEST_DIV64_DIVISOR_8,};#define SIZE_DIV64_DIVISORS ARRAY_SIZE(test_div64_divisors) static const struct {	u64 quotient;	u32 remainder;} test_div64_results[SIZE_DIV64_DIVISORS][SIZE_DIV64_DIVIDENDS] = {	{		{ 0x0000000013045e47, 0x00000001 },		{ 0x000000000161596c, 0x00000030 },		{ 0x000000000054e9d4, 0x00000130 },		{ 0x000000000000d776, 0x0000278e },		{ 0x000000000000ab27, 0x00005080 },		{ 0x00000000000013c4, 0x0004ce80 },		{ 0x00000000000002ae, 0x001e143c },		{ 0x000000000000000f, 0x0033e56c },		{ 0x0000000000000000, 0xab275080 },	}, {		{ 0x00000001c45c02d1, 0x00000000 },		{ 0x0000000020d5213c, 0x00000049 },		{ 0x0000000007e3d65f, 0x000001dd },		{ 0x0000000000140531, 0x000065ee },		{ 0x00000000000fe73c, 0x00001959 },		{ 0x000000000001d637, 0x0004e5d9 },		{ 0x0000000000003fc9, 0x000713bb },		{ 0x0000000000000165, 0x029abe7d },		{ 0x0000000000000012, 0x6e9f7e37 },	}, {		{ 0x000000197a3a0cf7, 0x00000002 },		{ 0x00000001d9632e5c, 0x00000021 },		{ 0x0000000071c28039, 0x000001cd },		{ 0x000000000120a844, 0x0000b885 },		{ 0x0000000000e54c0a, 0x000074b1 },		{ 0x00000000001a7bb3, 0x00072331 },		{ 0x00000000000397ad, 0x0002c61b },		{ 0x000000000000141e, 0x06ea2e89 },		{ 0x000000000000010a, 0xab002ad7 },	}, {		{ 0x0000017949e37538, 0x00000001 },		{ 0x0000001b62441f37, 0x00000055 },		{ 0x0000000694a3391d, 0x00000085 },		{ 0x0000000010b2a5d2, 0x0000a753 },		{ 0x000000000d4398ff, 0x00001ef9 },		{ 0x0000000001882ec6, 0x0005cbf9 },		{ 0x000000000035333b, 0x0017abdf },		{ 0x00000000000129f1, 0x0ab4520d },		{ 0x0000000000000f6e, 0x8ac0ce9b },	}, {		{ 0x000011f321a74e49, 0x00000006 },		{ 0x0000014d8481d211, 0x0000005b },		{ 0x0000005025cbd92d, 0x000001e3 },		{ 0x00000000cb5e71e3, 0x000043e6 },		{ 0x00000000a18c2ee1, 0x0000c097 },		{ 0x0000000012a88828, 0x00036c97 },		{ 0x000000000287f16f, 0x002c2a25 },		{ 0x00000000000e2cc7, 0x02d581e3 },		{ 0x000000000000bbf4, 0x1ba08c03 },	}, {		{ 0x0000d8db8f72935d, 0x00000005 },		{ 0x00000fbd5aed7a2e, 0x00000002 },		{ 0x000003c84b6ea64a, 0x00000122 },		{ 0x0000000998fa8829, 0x000044b7 },		{ 0x000000079fb80b07, 0x00002e4a },		{ 0x00000000e16b20fa, 0x0002a14a },		{ 0x000000001e940d22, 0x00353b2e },		{ 0x0000000000ab40ac, 0x06fba6ba },		{ 0x000000000008debd, 0x72d98365 },	}, {		{ 0x000cc3045b8fc281, 0x00000000 },		{ 0x0000ed1f48b5c9fc, 0x00000079 },		{ 0x000038fb9c63406a, 0x000000e1 },		{ 0x000000909705b825, 0x00000a62 },		{ 0x00000072db27380d, 0x0000d689 },		{ 0x0000000d43fce827, 0x00082b09 },		{ 0x00000001ccaba11a, 0x0037e8dd },		{ 0x000000000a13f729, 0x0566dffd },		{ 0x000000000085a14b, 0x23d36726 },	}, {		{ 0x00eafeb9c993592b, 0x00000001 },		{ 0x00110e5befa9a991, 0x00000048 },		{ 0x00041947b4a1d36a, 0x000000dc },		{ 0x00000a6679327311, 0x0000c079 },		{ 0x00000842f488162e, 0x00002284 },		{ 0x000000f4459740fc, 0x00084484 },		{ 0x0000002122c47bf9, 0x002ca446 },		{ 0x00000000b9936290, 0x004979c4 },		{ 0x00000000099ca89d, 0x9db446bf },	}, {		{ 0x1b60cece589da1d2, 0x00000001 },		{ 0x01fcb42be1453f5b, 0x0000004f },		{ 0x007a3f2457df0749, 0x0000013f },		{ 0x0001363130e3ec7b, 0x000017aa },		{ 0x0000f66745411d8a, 0x0000b063 },		{ 0x00001c757dfab350, 0x00048863 },		{ 0x000003dc4979c652, 0x00224ea7 },		{ 0x000000159edc3144, 0x06409ab3 },		{ 0x000000011eadfee3, 0xa99c48a8 },	},}; static inline bool test_div64_verify(u64 quotient, u32 remainder, int i, int j){	return (quotient == test_div64_results[i][j].quotient &&		remainder == test_div64_results[i][j].remainder);} /* * This needs to be a macro, because we don't want to rely on the compiler * to do constant propagation, and `do_div' may take a different path for * constants, so we do want to verify that as well. */#define test_div64_one(dividend, divisor, i, j) ({			\	bool result = true;						\	u64 quotient;							\	u32 remainder;							\									\	quotient = dividend;						\	remainder = do_div(quotient, divisor);				\	if (!test_div64_verify(quotient, remainder, i, j)) {		\		pr_err("ERROR: %016llx / %08x => %016llx,%08x\n",	\		       dividend, divisor, quotient, remainder);		\		pr_err("ERROR: expected value              => %016llx,%08x\n",\		       test_div64_results[i][j].quotient,		\		       test_div64_results[i][j].remainder);		\		result = false;						\	}								\	result;								\}) /* * Run calculation for the same divisor value expressed as a constant * and as a variable, so as to verify the implementation for both cases * should they be handled by different code execution paths. */static bool __init test_div64(void){	u64 dividend;	int i, j; 	for (i = 0; i < SIZE_DIV64_DIVIDENDS; i++) {		dividend = test_div64_dividends[i];		if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_0, i, 0))			return false;		if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_1, i, 1))			return false;		if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_2, i, 2))			return false;		if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_3, i, 3))			return false;		if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_4, i, 4))			return false;		if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_5, i, 5))			return false;		if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_6, i, 6))			return false;		if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_7, i, 7))			return false;		if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_8, i, 8))			return false;		for (j = 0; j < SIZE_DIV64_DIVISORS; j++) {			if (!test_div64_one(dividend, test_div64_divisors[j],					    i, j))				return false;		}	}	return true;} static int __init test_div64_init(void){	struct timespec64 ts, ts0, ts1;	int i; 	pr_info("Starting 64bit/32bit division and modulo test\n");	ktime_get_ts64(&ts0); 	for (i = 0; i < TEST_DIV64_N_ITER; i++)		if (!test_div64())			break; 	ktime_get_ts64(&ts1);	ts = timespec64_sub(ts1, ts0);	pr_info("Completed 64bit/32bit division and modulo test, "		"%llu.%09lus elapsed\n", ts.tv_sec, ts.tv_nsec); 	return 0;} static void __exit test_div64_exit(void){} module_init(test_div64_init);module_exit(test_div64_exit); MODULE_AUTHOR("Maciej W. Rozycki <macro@orcam.me.uk>");MODULE_LICENSE("GPL");MODULE_DESCRIPTION("64bit/32bit division and modulo test module");