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-rw-r--r--lib/math/test_div64.c330
1 files changed, 330 insertions, 0 deletions
diff --git a/lib/math/test_div64.c b/lib/math/test_div64.c
new file mode 100644
index 000000000000..3cd699b654d9
--- /dev/null
+++ b/lib/math/test_div64.c
@@ -0,0 +1,330 @@
+// 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,
+ 0xfffffffffffffffb,
+ 0xfffffffffffffffc,
+ 0xffffffffffffffff,
+};
+#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 0x80000001
+#define TEST_DIV64_DIVISOR_9 0xdc08b349
+#define TEST_DIV64_DIVISOR_A 0xfffffffe
+#define TEST_DIV64_DIVISOR_B 0xffffffff
+
+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,
+ TEST_DIV64_DIVISOR_9,
+ TEST_DIV64_DIVISOR_A,
+ TEST_DIV64_DIVISOR_B,
+};
+#define SIZE_DIV64_DIVISORS ARRAY_SIZE(test_div64_divisors)
+
+static const struct {
+ u64 quotient;
+ u32 remainder;
+} test_div64_results[SIZE_DIV64_DIVIDENDS][SIZE_DIV64_DIVISORS] = {
+ {
+ { 0x0000000013045e47, 0x00000001 },
+ { 0x000000000161596c, 0x00000030 },
+ { 0x000000000054e9d4, 0x00000130 },
+ { 0x000000000000d776, 0x0000278e },
+ { 0x000000000000ab27, 0x00005080 },
+ { 0x00000000000013c4, 0x0004ce80 },
+ { 0x00000000000002ae, 0x001e143c },
+ { 0x000000000000000f, 0x0033e56c },
+ { 0x0000000000000001, 0x2b27507f },
+ { 0x0000000000000000, 0xab275080 },
+ { 0x0000000000000000, 0xab275080 },
+ { 0x0000000000000000, 0xab275080 },
+ }, {
+ { 0x00000001c45c02d1, 0x00000000 },
+ { 0x0000000020d5213c, 0x00000049 },
+ { 0x0000000007e3d65f, 0x000001dd },
+ { 0x0000000000140531, 0x000065ee },
+ { 0x00000000000fe73c, 0x00001959 },
+ { 0x000000000001d637, 0x0004e5d9 },
+ { 0x0000000000003fc9, 0x000713bb },
+ { 0x0000000000000165, 0x029abe7d },
+ { 0x000000000000001f, 0x673c193a },
+ { 0x0000000000000012, 0x6e9f7e37 },
+ { 0x000000000000000f, 0xe73c1977 },
+ { 0x000000000000000f, 0xe73c1968 },
+ }, {
+ { 0x000000197a3a0cf7, 0x00000002 },
+ { 0x00000001d9632e5c, 0x00000021 },
+ { 0x0000000071c28039, 0x000001cd },
+ { 0x000000000120a844, 0x0000b885 },
+ { 0x0000000000e54c0a, 0x000074b1 },
+ { 0x00000000001a7bb3, 0x00072331 },
+ { 0x00000000000397ad, 0x0002c61b },
+ { 0x000000000000141e, 0x06ea2e89 },
+ { 0x00000000000001ca, 0x4c0a72e7 },
+ { 0x000000000000010a, 0xab002ad7 },
+ { 0x00000000000000e5, 0x4c0a767b },
+ { 0x00000000000000e5, 0x4c0a7596 },
+ }, {
+ { 0x0000017949e37538, 0x00000001 },
+ { 0x0000001b62441f37, 0x00000055 },
+ { 0x0000000694a3391d, 0x00000085 },
+ { 0x0000000010b2a5d2, 0x0000a753 },
+ { 0x000000000d4398ff, 0x00001ef9 },
+ { 0x0000000001882ec6, 0x0005cbf9 },
+ { 0x000000000035333b, 0x0017abdf },
+ { 0x00000000000129f1, 0x0ab4520d },
+ { 0x0000000000001a87, 0x18ff0472 },
+ { 0x0000000000000f6e, 0x8ac0ce9b },
+ { 0x0000000000000d43, 0x98ff397f },
+ { 0x0000000000000d43, 0x98ff2c3c },
+ }, {
+ { 0x000011f321a74e49, 0x00000006 },
+ { 0x0000014d8481d211, 0x0000005b },
+ { 0x0000005025cbd92d, 0x000001e3 },
+ { 0x00000000cb5e71e3, 0x000043e6 },
+ { 0x00000000a18c2ee1, 0x0000c097 },
+ { 0x0000000012a88828, 0x00036c97 },
+ { 0x000000000287f16f, 0x002c2a25 },
+ { 0x00000000000e2cc7, 0x02d581e3 },
+ { 0x0000000000014318, 0x2ee07d7f },
+ { 0x000000000000bbf4, 0x1ba08c03 },
+ { 0x000000000000a18c, 0x2ee303af },
+ { 0x000000000000a18c, 0x2ee26223 },
+ }, {
+ { 0x0000d8db8f72935d, 0x00000005 },
+ { 0x00000fbd5aed7a2e, 0x00000002 },
+ { 0x000003c84b6ea64a, 0x00000122 },
+ { 0x0000000998fa8829, 0x000044b7 },
+ { 0x000000079fb80b07, 0x00002e4a },
+ { 0x00000000e16b20fa, 0x0002a14a },
+ { 0x000000001e940d22, 0x00353b2e },
+ { 0x0000000000ab40ac, 0x06fba6ba },
+ { 0x00000000000f3f70, 0x0af7eeda },
+ { 0x000000000008debd, 0x72d98365 },
+ { 0x0000000000079fb8, 0x0b166dba },
+ { 0x0000000000079fb8, 0x0b0ece02 },
+ }, {
+ { 0x000cc3045b8fc281, 0x00000000 },
+ { 0x0000ed1f48b5c9fc, 0x00000079 },
+ { 0x000038fb9c63406a, 0x000000e1 },
+ { 0x000000909705b825, 0x00000a62 },
+ { 0x00000072db27380d, 0x0000d689 },
+ { 0x0000000d43fce827, 0x00082b09 },
+ { 0x00000001ccaba11a, 0x0037e8dd },
+ { 0x000000000a13f729, 0x0566dffd },
+ { 0x0000000000e5b64e, 0x3728203b },
+ { 0x000000000085a14b, 0x23d36726 },
+ { 0x000000000072db27, 0x38f38cd7 },
+ { 0x000000000072db27, 0x3880b1b0 },
+ }, {
+ { 0x00eafeb9c993592b, 0x00000001 },
+ { 0x00110e5befa9a991, 0x00000048 },
+ { 0x00041947b4a1d36a, 0x000000dc },
+ { 0x00000a6679327311, 0x0000c079 },
+ { 0x00000842f488162e, 0x00002284 },
+ { 0x000000f4459740fc, 0x00084484 },
+ { 0x0000002122c47bf9, 0x002ca446 },
+ { 0x00000000b9936290, 0x004979c4 },
+ { 0x000000001085e910, 0x05a83974 },
+ { 0x00000000099ca89d, 0x9db446bf },
+ { 0x000000000842f488, 0x26b40b94 },
+ { 0x000000000842f488, 0x1e71170c },
+ }, {
+ { 0x1b60cece589da1d2, 0x00000001 },
+ { 0x01fcb42be1453f5b, 0x0000004f },
+ { 0x007a3f2457df0749, 0x0000013f },
+ { 0x0001363130e3ec7b, 0x000017aa },
+ { 0x0000f66745411d8a, 0x0000b063 },
+ { 0x00001c757dfab350, 0x00048863 },
+ { 0x000003dc4979c652, 0x00224ea7 },
+ { 0x000000159edc3144, 0x06409ab3 },
+ { 0x00000001ecce8a7e, 0x30bc25e5 },
+ { 0x000000011eadfee3, 0xa99c48a8 },
+ { 0x00000000f6674543, 0x0a593ae9 },
+ { 0x00000000f6674542, 0x13f1f5a5 },
+ }, {
+ { 0x1c71c71c71c71c71, 0x00000002 },
+ { 0x0210842108421084, 0x0000000b },
+ { 0x007f01fc07f01fc0, 0x000000fb },
+ { 0x00014245eabf1f9a, 0x0000a63d },
+ { 0x0000ffffffffffff, 0x0000fffb },
+ { 0x00001d913cecc509, 0x0007937b },
+ { 0x00000402c70c678f, 0x0005bfc9 },
+ { 0x00000016766cb70b, 0x045edf97 },
+ { 0x00000001fffffffb, 0x80000000 },
+ { 0x0000000129d84b3a, 0xa2e8fe71 },
+ { 0x0000000100000001, 0xfffffffd },
+ { 0x0000000100000000, 0xfffffffb },
+ }, {
+ { 0x1c71c71c71c71c71, 0x00000003 },
+ { 0x0210842108421084, 0x0000000c },
+ { 0x007f01fc07f01fc0, 0x000000fc },
+ { 0x00014245eabf1f9a, 0x0000a63e },
+ { 0x0000ffffffffffff, 0x0000fffc },
+ { 0x00001d913cecc509, 0x0007937c },
+ { 0x00000402c70c678f, 0x0005bfca },
+ { 0x00000016766cb70b, 0x045edf98 },
+ { 0x00000001fffffffc, 0x00000000 },
+ { 0x0000000129d84b3a, 0xa2e8fe72 },
+ { 0x0000000100000002, 0x00000000 },
+ { 0x0000000100000000, 0xfffffffc },
+ }, {
+ { 0x1c71c71c71c71c71, 0x00000006 },
+ { 0x0210842108421084, 0x0000000f },
+ { 0x007f01fc07f01fc0, 0x000000ff },
+ { 0x00014245eabf1f9a, 0x0000a641 },
+ { 0x0000ffffffffffff, 0x0000ffff },
+ { 0x00001d913cecc509, 0x0007937f },
+ { 0x00000402c70c678f, 0x0005bfcd },
+ { 0x00000016766cb70b, 0x045edf9b },
+ { 0x00000001fffffffc, 0x00000003 },
+ { 0x0000000129d84b3a, 0xa2e8fe75 },
+ { 0x0000000100000002, 0x00000003 },
+ { 0x0000000100000001, 0x00000000 },
+ },
+};
+
+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;
+ if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_9, i, 9))
+ return false;
+ if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_A, i, 10))
+ return false;
+ if (!test_div64_one(dividend, TEST_DIV64_DIVISOR_B, i, 11))
+ 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");
generated by cgit (git 2.34.1) at 2025-12-21 22:48:16 +0000