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// 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");
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