mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-12-28 16:56:26 +00:00
1dc82675cb
Be sure to test the extreme cases with and without bias. Signed-off-by: Nicolas Pitre <npitre@baylibre.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
331 lines
10 KiB
C
331 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2021 Maciej W. Rozycki
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/init.h>
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#include <linux/ktime.h>
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#include <linux/module.h>
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#include <linux/printk.h>
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#include <linux/time64.h>
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#include <linux/types.h>
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#include <asm/div64.h>
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#define TEST_DIV64_N_ITER 1024
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static const u64 test_div64_dividends[] = {
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0x00000000ab275080,
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0x0000000fe73c1959,
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0x000000e54c0a74b1,
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0x00000d4398ff1ef9,
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0x0000a18c2ee1c097,
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0x00079fb80b072e4a,
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0x0072db27380dd689,
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0x0842f488162e2284,
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0xf66745411d8ab063,
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0xfffffffffffffffb,
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0xfffffffffffffffc,
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0xffffffffffffffff,
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};
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#define SIZE_DIV64_DIVIDENDS ARRAY_SIZE(test_div64_dividends)
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#define TEST_DIV64_DIVISOR_0 0x00000009
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#define TEST_DIV64_DIVISOR_1 0x0000007c
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#define TEST_DIV64_DIVISOR_2 0x00000204
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#define TEST_DIV64_DIVISOR_3 0x0000cb5b
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#define TEST_DIV64_DIVISOR_4 0x00010000
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#define TEST_DIV64_DIVISOR_5 0x0008a880
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#define TEST_DIV64_DIVISOR_6 0x003fd3ae
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#define TEST_DIV64_DIVISOR_7 0x0b658fac
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#define TEST_DIV64_DIVISOR_8 0x80000001
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#define TEST_DIV64_DIVISOR_9 0xdc08b349
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#define TEST_DIV64_DIVISOR_A 0xfffffffe
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#define TEST_DIV64_DIVISOR_B 0xffffffff
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static const u32 test_div64_divisors[] = {
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TEST_DIV64_DIVISOR_0,
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TEST_DIV64_DIVISOR_1,
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TEST_DIV64_DIVISOR_2,
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TEST_DIV64_DIVISOR_3,
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TEST_DIV64_DIVISOR_4,
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TEST_DIV64_DIVISOR_5,
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TEST_DIV64_DIVISOR_6,
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TEST_DIV64_DIVISOR_7,
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TEST_DIV64_DIVISOR_8,
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TEST_DIV64_DIVISOR_9,
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TEST_DIV64_DIVISOR_A,
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TEST_DIV64_DIVISOR_B,
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};
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#define SIZE_DIV64_DIVISORS ARRAY_SIZE(test_div64_divisors)
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static const struct {
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u64 quotient;
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u32 remainder;
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} test_div64_results[SIZE_DIV64_DIVIDENDS][SIZE_DIV64_DIVISORS] = {
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{
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{ 0x0000000013045e47, 0x00000001 },
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{ 0x000000000161596c, 0x00000030 },
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{ 0x000000000054e9d4, 0x00000130 },
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{ 0x000000000000d776, 0x0000278e },
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{ 0x000000000000ab27, 0x00005080 },
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{ 0x00000000000013c4, 0x0004ce80 },
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{ 0x00000000000002ae, 0x001e143c },
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{ 0x000000000000000f, 0x0033e56c },
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{ 0x0000000000000001, 0x2b27507f },
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{ 0x0000000000000000, 0xab275080 },
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{ 0x0000000000000000, 0xab275080 },
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{ 0x0000000000000000, 0xab275080 },
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}, {
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{ 0x00000001c45c02d1, 0x00000000 },
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{ 0x0000000020d5213c, 0x00000049 },
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{ 0x0000000007e3d65f, 0x000001dd },
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{ 0x0000000000140531, 0x000065ee },
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{ 0x00000000000fe73c, 0x00001959 },
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{ 0x000000000001d637, 0x0004e5d9 },
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{ 0x0000000000003fc9, 0x000713bb },
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{ 0x0000000000000165, 0x029abe7d },
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{ 0x000000000000001f, 0x673c193a },
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{ 0x0000000000000012, 0x6e9f7e37 },
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{ 0x000000000000000f, 0xe73c1977 },
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{ 0x000000000000000f, 0xe73c1968 },
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}, {
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{ 0x000000197a3a0cf7, 0x00000002 },
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{ 0x00000001d9632e5c, 0x00000021 },
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{ 0x0000000071c28039, 0x000001cd },
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{ 0x000000000120a844, 0x0000b885 },
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{ 0x0000000000e54c0a, 0x000074b1 },
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{ 0x00000000001a7bb3, 0x00072331 },
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{ 0x00000000000397ad, 0x0002c61b },
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{ 0x000000000000141e, 0x06ea2e89 },
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{ 0x00000000000001ca, 0x4c0a72e7 },
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{ 0x000000000000010a, 0xab002ad7 },
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{ 0x00000000000000e5, 0x4c0a767b },
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{ 0x00000000000000e5, 0x4c0a7596 },
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}, {
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{ 0x0000017949e37538, 0x00000001 },
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{ 0x0000001b62441f37, 0x00000055 },
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{ 0x0000000694a3391d, 0x00000085 },
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{ 0x0000000010b2a5d2, 0x0000a753 },
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{ 0x000000000d4398ff, 0x00001ef9 },
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{ 0x0000000001882ec6, 0x0005cbf9 },
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{ 0x000000000035333b, 0x0017abdf },
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{ 0x00000000000129f1, 0x0ab4520d },
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{ 0x0000000000001a87, 0x18ff0472 },
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{ 0x0000000000000f6e, 0x8ac0ce9b },
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{ 0x0000000000000d43, 0x98ff397f },
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{ 0x0000000000000d43, 0x98ff2c3c },
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}, {
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{ 0x000011f321a74e49, 0x00000006 },
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{ 0x0000014d8481d211, 0x0000005b },
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{ 0x0000005025cbd92d, 0x000001e3 },
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{ 0x00000000cb5e71e3, 0x000043e6 },
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{ 0x00000000a18c2ee1, 0x0000c097 },
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{ 0x0000000012a88828, 0x00036c97 },
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{ 0x000000000287f16f, 0x002c2a25 },
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{ 0x00000000000e2cc7, 0x02d581e3 },
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{ 0x0000000000014318, 0x2ee07d7f },
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{ 0x000000000000bbf4, 0x1ba08c03 },
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{ 0x000000000000a18c, 0x2ee303af },
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{ 0x000000000000a18c, 0x2ee26223 },
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}, {
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{ 0x0000d8db8f72935d, 0x00000005 },
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{ 0x00000fbd5aed7a2e, 0x00000002 },
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{ 0x000003c84b6ea64a, 0x00000122 },
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{ 0x0000000998fa8829, 0x000044b7 },
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{ 0x000000079fb80b07, 0x00002e4a },
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{ 0x00000000e16b20fa, 0x0002a14a },
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{ 0x000000001e940d22, 0x00353b2e },
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{ 0x0000000000ab40ac, 0x06fba6ba },
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{ 0x00000000000f3f70, 0x0af7eeda },
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{ 0x000000000008debd, 0x72d98365 },
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{ 0x0000000000079fb8, 0x0b166dba },
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{ 0x0000000000079fb8, 0x0b0ece02 },
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}, {
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{ 0x000cc3045b8fc281, 0x00000000 },
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{ 0x0000ed1f48b5c9fc, 0x00000079 },
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{ 0x000038fb9c63406a, 0x000000e1 },
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{ 0x000000909705b825, 0x00000a62 },
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{ 0x00000072db27380d, 0x0000d689 },
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{ 0x0000000d43fce827, 0x00082b09 },
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{ 0x00000001ccaba11a, 0x0037e8dd },
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{ 0x000000000a13f729, 0x0566dffd },
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{ 0x0000000000e5b64e, 0x3728203b },
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{ 0x000000000085a14b, 0x23d36726 },
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{ 0x000000000072db27, 0x38f38cd7 },
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{ 0x000000000072db27, 0x3880b1b0 },
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}, {
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{ 0x00eafeb9c993592b, 0x00000001 },
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{ 0x00110e5befa9a991, 0x00000048 },
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{ 0x00041947b4a1d36a, 0x000000dc },
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{ 0x00000a6679327311, 0x0000c079 },
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{ 0x00000842f488162e, 0x00002284 },
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{ 0x000000f4459740fc, 0x00084484 },
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{ 0x0000002122c47bf9, 0x002ca446 },
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{ 0x00000000b9936290, 0x004979c4 },
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{ 0x000000001085e910, 0x05a83974 },
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{ 0x00000000099ca89d, 0x9db446bf },
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{ 0x000000000842f488, 0x26b40b94 },
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{ 0x000000000842f488, 0x1e71170c },
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}, {
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{ 0x1b60cece589da1d2, 0x00000001 },
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{ 0x01fcb42be1453f5b, 0x0000004f },
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{ 0x007a3f2457df0749, 0x0000013f },
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{ 0x0001363130e3ec7b, 0x000017aa },
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{ 0x0000f66745411d8a, 0x0000b063 },
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{ 0x00001c757dfab350, 0x00048863 },
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{ 0x000003dc4979c652, 0x00224ea7 },
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{ 0x000000159edc3144, 0x06409ab3 },
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{ 0x00000001ecce8a7e, 0x30bc25e5 },
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{ 0x000000011eadfee3, 0xa99c48a8 },
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{ 0x00000000f6674543, 0x0a593ae9 },
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{ 0x00000000f6674542, 0x13f1f5a5 },
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}, {
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{ 0x1c71c71c71c71c71, 0x00000002 },
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{ 0x0210842108421084, 0x0000000b },
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{ 0x007f01fc07f01fc0, 0x000000fb },
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{ 0x00014245eabf1f9a, 0x0000a63d },
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{ 0x0000ffffffffffff, 0x0000fffb },
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{ 0x00001d913cecc509, 0x0007937b },
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{ 0x00000402c70c678f, 0x0005bfc9 },
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{ 0x00000016766cb70b, 0x045edf97 },
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{ 0x00000001fffffffb, 0x80000000 },
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{ 0x0000000129d84b3a, 0xa2e8fe71 },
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{ 0x0000000100000001, 0xfffffffd },
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{ 0x0000000100000000, 0xfffffffb },
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}, {
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{ 0x1c71c71c71c71c71, 0x00000003 },
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{ 0x0210842108421084, 0x0000000c },
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{ 0x007f01fc07f01fc0, 0x000000fc },
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{ 0x00014245eabf1f9a, 0x0000a63e },
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{ 0x0000ffffffffffff, 0x0000fffc },
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{ 0x00001d913cecc509, 0x0007937c },
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{ 0x00000402c70c678f, 0x0005bfca },
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{ 0x00000016766cb70b, 0x045edf98 },
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{ 0x00000001fffffffc, 0x00000000 },
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{ 0x0000000129d84b3a, 0xa2e8fe72 },
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{ 0x0000000100000002, 0x00000000 },
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{ 0x0000000100000000, 0xfffffffc },
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}, {
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{ 0x1c71c71c71c71c71, 0x00000006 },
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{ 0x0210842108421084, 0x0000000f },
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{ 0x007f01fc07f01fc0, 0x000000ff },
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{ 0x00014245eabf1f9a, 0x0000a641 },
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{ 0x0000ffffffffffff, 0x0000ffff },
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{ 0x00001d913cecc509, 0x0007937f },
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{ 0x00000402c70c678f, 0x0005bfcd },
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{ 0x00000016766cb70b, 0x045edf9b },
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{ 0x00000001fffffffc, 0x00000003 },
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{ 0x0000000129d84b3a, 0xa2e8fe75 },
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{ 0x0000000100000002, 0x00000003 },
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{ 0x0000000100000001, 0x00000000 },
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},
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};
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static inline bool test_div64_verify(u64 quotient, u32 remainder, int i, int j)
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{
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return (quotient == test_div64_results[i][j].quotient &&
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remainder == test_div64_results[i][j].remainder);
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}
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/*
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* This needs to be a macro, because we don't want to rely on the compiler
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* to do constant propagation, and `do_div' may take a different path for
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* constants, so we do want to verify that as well.
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*/
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#define test_div64_one(dividend, divisor, i, j) ({ \
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bool result = true; \
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u64 quotient; \
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u32 remainder; \
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\
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quotient = dividend; \
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remainder = do_div(quotient, divisor); \
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if (!test_div64_verify(quotient, remainder, i, j)) { \
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pr_err("ERROR: %016llx / %08x => %016llx,%08x\n", \
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dividend, divisor, quotient, remainder); \
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pr_err("ERROR: expected value => %016llx,%08x\n",\
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test_div64_results[i][j].quotient, \
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test_div64_results[i][j].remainder); \
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result = false; \
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} \
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result; \
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})
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/*
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* Run calculation for the same divisor value expressed as a constant
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* and as a variable, so as to verify the implementation for both cases
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* should they be handled by different code execution paths.
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*/
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static bool __init test_div64(void)
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{
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u64 dividend;
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int i, j;
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for (i = 0; i < SIZE_DIV64_DIVIDENDS; i++) {
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dividend = test_div64_dividends[i];
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if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_0, i, 0))
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return false;
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if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_1, i, 1))
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return false;
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if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_2, i, 2))
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return false;
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if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_3, i, 3))
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return false;
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if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_4, i, 4))
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return false;
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if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_5, i, 5))
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return false;
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if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_6, i, 6))
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return false;
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if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_7, i, 7))
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return false;
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if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_8, i, 8))
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return false;
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if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_9, i, 9))
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return false;
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if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_A, i, 10))
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return false;
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if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_B, i, 11))
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return false;
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for (j = 0; j < SIZE_DIV64_DIVISORS; j++) {
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if (!test_div64_one(dividend, test_div64_divisors[j],
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i, j))
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return false;
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}
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}
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return true;
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}
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static int __init test_div64_init(void)
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{
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struct timespec64 ts, ts0, ts1;
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int i;
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pr_info("Starting 64bit/32bit division and modulo test\n");
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ktime_get_ts64(&ts0);
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for (i = 0; i < TEST_DIV64_N_ITER; i++)
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if (!test_div64())
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break;
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ktime_get_ts64(&ts1);
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ts = timespec64_sub(ts1, ts0);
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pr_info("Completed 64bit/32bit division and modulo test, "
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"%llu.%09lus elapsed\n", ts.tv_sec, ts.tv_nsec);
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return 0;
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}
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static void __exit test_div64_exit(void)
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{
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}
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module_init(test_div64_init);
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module_exit(test_div64_exit);
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MODULE_AUTHOR("Maciej W. Rozycki <macro@orcam.me.uk>");
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("64bit/32bit division and modulo test module");
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