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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
19static const u64 test_div64_dividends[] = {
20 0x00000000ab275080,
21 0x0000000fe73c1959,
22 0x000000e54c0a74b1,
23 0x00000d4398ff1ef9,
24 0x0000a18c2ee1c097,
25 0x00079fb80b072e4a,
26 0x0072db27380dd689,
27 0x0842f488162e2284,
28 0xf66745411d8ab063,
29 0xfffffffffffffffb,
30 0xfffffffffffffffc,
31 0xffffffffffffffff,
32};
33#define SIZE_DIV64_DIVIDENDS ARRAY_SIZE(test_div64_dividends)
34
35#define TEST_DIV64_DIVISOR_0 0x00000009
36#define TEST_DIV64_DIVISOR_1 0x0000007c
37#define TEST_DIV64_DIVISOR_2 0x00000204
38#define TEST_DIV64_DIVISOR_3 0x0000cb5b
39#define TEST_DIV64_DIVISOR_4 0x00010000
40#define TEST_DIV64_DIVISOR_5 0x0008a880
41#define TEST_DIV64_DIVISOR_6 0x003fd3ae
42#define TEST_DIV64_DIVISOR_7 0x0b658fac
43#define TEST_DIV64_DIVISOR_8 0x80000001
44#define TEST_DIV64_DIVISOR_9 0xdc08b349
45#define TEST_DIV64_DIVISOR_A 0xfffffffe
46#define TEST_DIV64_DIVISOR_B 0xffffffff
47
48static const u32 test_div64_divisors[] = {
49 TEST_DIV64_DIVISOR_0,
50 TEST_DIV64_DIVISOR_1,
51 TEST_DIV64_DIVISOR_2,
52 TEST_DIV64_DIVISOR_3,
53 TEST_DIV64_DIVISOR_4,
54 TEST_DIV64_DIVISOR_5,
55 TEST_DIV64_DIVISOR_6,
56 TEST_DIV64_DIVISOR_7,
57 TEST_DIV64_DIVISOR_8,
58 TEST_DIV64_DIVISOR_9,
59 TEST_DIV64_DIVISOR_A,
60 TEST_DIV64_DIVISOR_B,
61};
62#define SIZE_DIV64_DIVISORS ARRAY_SIZE(test_div64_divisors)
63
64static const struct {
65 u64 quotient;
66 u32 remainder;
67} test_div64_results[SIZE_DIV64_DIVIDENDS][SIZE_DIV64_DIVISORS] = {
68 {
69 { 0x0000000013045e47, 0x00000001 },
70 { 0x000000000161596c, 0x00000030 },
71 { 0x000000000054e9d4, 0x00000130 },
72 { 0x000000000000d776, 0x0000278e },
73 { 0x000000000000ab27, 0x00005080 },
74 { 0x00000000000013c4, 0x0004ce80 },
75 { 0x00000000000002ae, 0x001e143c },
76 { 0x000000000000000f, 0x0033e56c },
77 { 0x0000000000000001, 0x2b27507f },
78 { 0x0000000000000000, 0xab275080 },
79 { 0x0000000000000000, 0xab275080 },
80 { 0x0000000000000000, 0xab275080 },
81 }, {
82 { 0x00000001c45c02d1, 0x00000000 },
83 { 0x0000000020d5213c, 0x00000049 },
84 { 0x0000000007e3d65f, 0x000001dd },
85 { 0x0000000000140531, 0x000065ee },
86 { 0x00000000000fe73c, 0x00001959 },
87 { 0x000000000001d637, 0x0004e5d9 },
88 { 0x0000000000003fc9, 0x000713bb },
89 { 0x0000000000000165, 0x029abe7d },
90 { 0x000000000000001f, 0x673c193a },
91 { 0x0000000000000012, 0x6e9f7e37 },
92 { 0x000000000000000f, 0xe73c1977 },
93 { 0x000000000000000f, 0xe73c1968 },
94 }, {
95 { 0x000000197a3a0cf7, 0x00000002 },
96 { 0x00000001d9632e5c, 0x00000021 },
97 { 0x0000000071c28039, 0x000001cd },
98 { 0x000000000120a844, 0x0000b885 },
99 { 0x0000000000e54c0a, 0x000074b1 },
100 { 0x00000000001a7bb3, 0x00072331 },
101 { 0x00000000000397ad, 0x0002c61b },
102 { 0x000000000000141e, 0x06ea2e89 },
103 { 0x00000000000001ca, 0x4c0a72e7 },
104 { 0x000000000000010a, 0xab002ad7 },
105 { 0x00000000000000e5, 0x4c0a767b },
106 { 0x00000000000000e5, 0x4c0a7596 },
107 }, {
108 { 0x0000017949e37538, 0x00000001 },
109 { 0x0000001b62441f37, 0x00000055 },
110 { 0x0000000694a3391d, 0x00000085 },
111 { 0x0000000010b2a5d2, 0x0000a753 },
112 { 0x000000000d4398ff, 0x00001ef9 },
113 { 0x0000000001882ec6, 0x0005cbf9 },
114 { 0x000000000035333b, 0x0017abdf },
115 { 0x00000000000129f1, 0x0ab4520d },
116 { 0x0000000000001a87, 0x18ff0472 },
117 { 0x0000000000000f6e, 0x8ac0ce9b },
118 { 0x0000000000000d43, 0x98ff397f },
119 { 0x0000000000000d43, 0x98ff2c3c },
120 }, {
121 { 0x000011f321a74e49, 0x00000006 },
122 { 0x0000014d8481d211, 0x0000005b },
123 { 0x0000005025cbd92d, 0x000001e3 },
124 { 0x00000000cb5e71e3, 0x000043e6 },
125 { 0x00000000a18c2ee1, 0x0000c097 },
126 { 0x0000000012a88828, 0x00036c97 },
127 { 0x000000000287f16f, 0x002c2a25 },
128 { 0x00000000000e2cc7, 0x02d581e3 },
129 { 0x0000000000014318, 0x2ee07d7f },
130 { 0x000000000000bbf4, 0x1ba08c03 },
131 { 0x000000000000a18c, 0x2ee303af },
132 { 0x000000000000a18c, 0x2ee26223 },
133 }, {
134 { 0x0000d8db8f72935d, 0x00000005 },
135 { 0x00000fbd5aed7a2e, 0x00000002 },
136 { 0x000003c84b6ea64a, 0x00000122 },
137 { 0x0000000998fa8829, 0x000044b7 },
138 { 0x000000079fb80b07, 0x00002e4a },
139 { 0x00000000e16b20fa, 0x0002a14a },
140 { 0x000000001e940d22, 0x00353b2e },
141 { 0x0000000000ab40ac, 0x06fba6ba },
142 { 0x00000000000f3f70, 0x0af7eeda },
143 { 0x000000000008debd, 0x72d98365 },
144 { 0x0000000000079fb8, 0x0b166dba },
145 { 0x0000000000079fb8, 0x0b0ece02 },
146 }, {
147 { 0x000cc3045b8fc281, 0x00000000 },
148 { 0x0000ed1f48b5c9fc, 0x00000079 },
149 { 0x000038fb9c63406a, 0x000000e1 },
150 { 0x000000909705b825, 0x00000a62 },
151 { 0x00000072db27380d, 0x0000d689 },
152 { 0x0000000d43fce827, 0x00082b09 },
153 { 0x00000001ccaba11a, 0x0037e8dd },
154 { 0x000000000a13f729, 0x0566dffd },
155 { 0x0000000000e5b64e, 0x3728203b },
156 { 0x000000000085a14b, 0x23d36726 },
157 { 0x000000000072db27, 0x38f38cd7 },
158 { 0x000000000072db27, 0x3880b1b0 },
159 }, {
160 { 0x00eafeb9c993592b, 0x00000001 },
161 { 0x00110e5befa9a991, 0x00000048 },
162 { 0x00041947b4a1d36a, 0x000000dc },
163 { 0x00000a6679327311, 0x0000c079 },
164 { 0x00000842f488162e, 0x00002284 },
165 { 0x000000f4459740fc, 0x00084484 },
166 { 0x0000002122c47bf9, 0x002ca446 },
167 { 0x00000000b9936290, 0x004979c4 },
168 { 0x000000001085e910, 0x05a83974 },
169 { 0x00000000099ca89d, 0x9db446bf },
170 { 0x000000000842f488, 0x26b40b94 },
171 { 0x000000000842f488, 0x1e71170c },
172 }, {
173 { 0x1b60cece589da1d2, 0x00000001 },
174 { 0x01fcb42be1453f5b, 0x0000004f },
175 { 0x007a3f2457df0749, 0x0000013f },
176 { 0x0001363130e3ec7b, 0x000017aa },
177 { 0x0000f66745411d8a, 0x0000b063 },
178 { 0x00001c757dfab350, 0x00048863 },
179 { 0x000003dc4979c652, 0x00224ea7 },
180 { 0x000000159edc3144, 0x06409ab3 },
181 { 0x00000001ecce8a7e, 0x30bc25e5 },
182 { 0x000000011eadfee3, 0xa99c48a8 },
183 { 0x00000000f6674543, 0x0a593ae9 },
184 { 0x00000000f6674542, 0x13f1f5a5 },
185 }, {
186 { 0x1c71c71c71c71c71, 0x00000002 },
187 { 0x0210842108421084, 0x0000000b },
188 { 0x007f01fc07f01fc0, 0x000000fb },
189 { 0x00014245eabf1f9a, 0x0000a63d },
190 { 0x0000ffffffffffff, 0x0000fffb },
191 { 0x00001d913cecc509, 0x0007937b },
192 { 0x00000402c70c678f, 0x0005bfc9 },
193 { 0x00000016766cb70b, 0x045edf97 },
194 { 0x00000001fffffffb, 0x80000000 },
195 { 0x0000000129d84b3a, 0xa2e8fe71 },
196 { 0x0000000100000001, 0xfffffffd },
197 { 0x0000000100000000, 0xfffffffb },
198 }, {
199 { 0x1c71c71c71c71c71, 0x00000003 },
200 { 0x0210842108421084, 0x0000000c },
201 { 0x007f01fc07f01fc0, 0x000000fc },
202 { 0x00014245eabf1f9a, 0x0000a63e },
203 { 0x0000ffffffffffff, 0x0000fffc },
204 { 0x00001d913cecc509, 0x0007937c },
205 { 0x00000402c70c678f, 0x0005bfca },
206 { 0x00000016766cb70b, 0x045edf98 },
207 { 0x00000001fffffffc, 0x00000000 },
208 { 0x0000000129d84b3a, 0xa2e8fe72 },
209 { 0x0000000100000002, 0x00000000 },
210 { 0x0000000100000000, 0xfffffffc },
211 }, {
212 { 0x1c71c71c71c71c71, 0x00000006 },
213 { 0x0210842108421084, 0x0000000f },
214 { 0x007f01fc07f01fc0, 0x000000ff },
215 { 0x00014245eabf1f9a, 0x0000a641 },
216 { 0x0000ffffffffffff, 0x0000ffff },
217 { 0x00001d913cecc509, 0x0007937f },
218 { 0x00000402c70c678f, 0x0005bfcd },
219 { 0x00000016766cb70b, 0x045edf9b },
220 { 0x00000001fffffffc, 0x00000003 },
221 { 0x0000000129d84b3a, 0xa2e8fe75 },
222 { 0x0000000100000002, 0x00000003 },
223 { 0x0000000100000001, 0x00000000 },
224 },
225};
226
227static inline bool test_div64_verify(u64 quotient, u32 remainder, int i, int j)
228{
229 return (quotient == test_div64_results[i][j].quotient &&
230 remainder == test_div64_results[i][j].remainder);
231}
232
233/*
234 * This needs to be a macro, because we don't want to rely on the compiler
235 * to do constant propagation, and `do_div' may take a different path for
236 * constants, so we do want to verify that as well.
237 */
238#define test_div64_one(dividend, divisor, i, j) ({ \
239 bool result = true; \
240 u64 quotient; \
241 u32 remainder; \
242 \
243 quotient = dividend; \
244 remainder = do_div(quotient, divisor); \
245 if (!test_div64_verify(quotient, remainder, i, j)) { \
246 pr_err("ERROR: %016llx / %08x => %016llx,%08x\n", \
247 dividend, divisor, quotient, remainder); \
248 pr_err("ERROR: expected value => %016llx,%08x\n",\
249 test_div64_results[i][j].quotient, \
250 test_div64_results[i][j].remainder); \
251 result = false; \
252 } \
253 result; \
254})
255
256/*
257 * Run calculation for the same divisor value expressed as a constant
258 * and as a variable, so as to verify the implementation for both cases
259 * should they be handled by different code execution paths.
260 */
261static bool __init test_div64(void)
262{
263 u64 dividend;
264 int i, j;
265
266 for (i = 0; i < SIZE_DIV64_DIVIDENDS; i++) {
267 dividend = test_div64_dividends[i];
268 if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_0, i, 0))
269 return false;
270 if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_1, i, 1))
271 return false;
272 if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_2, i, 2))
273 return false;
274 if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_3, i, 3))
275 return false;
276 if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_4, i, 4))
277 return false;
278 if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_5, i, 5))
279 return false;
280 if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_6, i, 6))
281 return false;
282 if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_7, i, 7))
283 return false;
284 if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_8, i, 8))
285 return false;
286 if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_9, i, 9))
287 return false;
288 if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_A, i, 10))
289 return false;
290 if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_B, i, 11))
291 return false;
292 for (j = 0; j < SIZE_DIV64_DIVISORS; j++) {
293 if (!test_div64_one(dividend, test_div64_divisors[j],
294 i, j))
295 return false;
296 }
297 }
298 return true;
299}
300
301static int __init test_div64_init(void)
302{
303 struct timespec64 ts, ts0, ts1;
304 int i;
305
306 pr_info("Starting 64bit/32bit division and modulo test\n");
307 ktime_get_ts64(&ts0);
308
309 for (i = 0; i < TEST_DIV64_N_ITER; i++)
310 if (!test_div64())
311 break;
312
313 ktime_get_ts64(&ts1);
314 ts = timespec64_sub(ts1, ts0);
315 pr_info("Completed 64bit/32bit division and modulo test, "
316 "%llu.%09lus elapsed\n", ts.tv_sec, ts.tv_nsec);
317
318 return 0;
319}
320
321static void __exit test_div64_exit(void)
322{
323}
324
325module_init(test_div64_init);
326module_exit(test_div64_exit);
327
328MODULE_AUTHOR("Maciej W. Rozycki <macro@orcam.me.uk>");
329MODULE_LICENSE("GPL");
330MODULE_DESCRIPTION("64bit/32bit division and modulo test module");