From: David Laight <david.laight.linux@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org
Cc: David Laight <david.laight.linux@gmail.com>,
u.kleine-koenig@baylibre.com, Nicolas Pitre <npitre@baylibre.com>,
Oleg Nesterov <oleg@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Biju Das <biju.das.jz@bp.renesas.com>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Li RongQing <lirongqing@baidu.com>,
Khazhismel Kumykov <khazhy@chromium.org>,
Jens Axboe <axboe@kernel.dk>,
x86@kernel.org
Subject: [PATCH v5 next 5/9] lib: Add tests for mul_u64_u64_div_u64_roundup()
Date: Wed, 5 Nov 2025 20:10:31 +0000 [thread overview]
Message-ID: <20251105201035.64043-6-david.laight.linux@gmail.com> (raw)
In-Reply-To: <20251105201035.64043-1-david.laight.linux@gmail.com>
Replicate the existing mul_u64_u64_div_u64() test cases with round up.
Update the shell script that verifies the table, remove the comment
markers so that it can be directly pasted into a shell.
Rename the divisor from 'c' to 'd' to match mul_u64_add_u64_div_u64().
It any tests fail then fail the module load with -EINVAL.
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Reviewed-by: Nicolas Pitre <npitre@baylibre.com>
---
Changes for v3:
- Rename 'c' to 'd' to match mul_u64_add_u64_div_u64()
Changes for v4:
- Fix shell script that verifies the table
lib/math/test_mul_u64_u64_div_u64.c | 122 +++++++++++++++++-----------
1 file changed, 73 insertions(+), 49 deletions(-)
diff --git a/lib/math/test_mul_u64_u64_div_u64.c b/lib/math/test_mul_u64_u64_div_u64.c
index 58d058de4e73..4d5e4e5dac67 100644
--- a/lib/math/test_mul_u64_u64_div_u64.c
+++ b/lib/math/test_mul_u64_u64_div_u64.c
@@ -10,61 +10,73 @@
#include <linux/printk.h>
#include <linux/math64.h>
-typedef struct { u64 a; u64 b; u64 c; u64 result; } test_params;
+typedef struct { u64 a; u64 b; u64 d; u64 result; uint round_up;} test_params;
static test_params test_values[] = {
/* this contains many edge values followed by a couple random values */
-{ 0xb, 0x7, 0x3, 0x19 },
-{ 0xffff0000, 0xffff0000, 0xf, 0x1110eeef00000000 },
-{ 0xffffffff, 0xffffffff, 0x1, 0xfffffffe00000001 },
-{ 0xffffffff, 0xffffffff, 0x2, 0x7fffffff00000000 },
-{ 0x1ffffffff, 0xffffffff, 0x2, 0xfffffffe80000000 },
-{ 0x1ffffffff, 0xffffffff, 0x3, 0xaaaaaaa9aaaaaaab },
-{ 0x1ffffffff, 0x1ffffffff, 0x4, 0xffffffff00000000 },
-{ 0xffff000000000000, 0xffff000000000000, 0xffff000000000001, 0xfffeffffffffffff },
-{ 0x3333333333333333, 0x3333333333333333, 0x5555555555555555, 0x1eb851eb851eb851 },
-{ 0x7fffffffffffffff, 0x2, 0x3, 0x5555555555555554 },
-{ 0xffffffffffffffff, 0x2, 0x8000000000000000, 0x3 },
-{ 0xffffffffffffffff, 0x2, 0xc000000000000000, 0x2 },
-{ 0xffffffffffffffff, 0x4000000000000004, 0x8000000000000000, 0x8000000000000007 },
-{ 0xffffffffffffffff, 0x4000000000000001, 0x8000000000000000, 0x8000000000000001 },
-{ 0xffffffffffffffff, 0x8000000000000001, 0xffffffffffffffff, 0x8000000000000001 },
-{ 0xfffffffffffffffe, 0x8000000000000001, 0xffffffffffffffff, 0x8000000000000000 },
-{ 0xffffffffffffffff, 0x8000000000000001, 0xfffffffffffffffe, 0x8000000000000001 },
-{ 0xffffffffffffffff, 0x8000000000000001, 0xfffffffffffffffd, 0x8000000000000002 },
-{ 0x7fffffffffffffff, 0xffffffffffffffff, 0xc000000000000000, 0xaaaaaaaaaaaaaaa8 },
-{ 0xffffffffffffffff, 0x7fffffffffffffff, 0xa000000000000000, 0xccccccccccccccca },
-{ 0xffffffffffffffff, 0x7fffffffffffffff, 0x9000000000000000, 0xe38e38e38e38e38b },
-{ 0x7fffffffffffffff, 0x7fffffffffffffff, 0x5000000000000000, 0xccccccccccccccc9 },
-{ 0xffffffffffffffff, 0xfffffffffffffffe, 0xffffffffffffffff, 0xfffffffffffffffe },
-{ 0xe6102d256d7ea3ae, 0x70a77d0be4c31201, 0xd63ec35ab3220357, 0x78f8bf8cc86c6e18 },
-{ 0xf53bae05cb86c6e1, 0x3847b32d2f8d32e0, 0xcfd4f55a647f403c, 0x42687f79d8998d35 },
-{ 0x9951c5498f941092, 0x1f8c8bfdf287a251, 0xa3c8dc5f81ea3fe2, 0x1d887cb25900091f },
-{ 0x374fee9daa1bb2bb, 0x0d0bfbff7b8ae3ef, 0xc169337bd42d5179, 0x03bb2dbaffcbb961 },
-{ 0xeac0d03ac10eeaf0, 0x89be05dfa162ed9b, 0x92bb1679a41f0e4b, 0xdc5f5cc9e270d216 },
+{ 0xb, 0x7, 0x3, 0x19, 1 },
+{ 0xffff0000, 0xffff0000, 0xf, 0x1110eeef00000000, 0 },
+{ 0xffffffff, 0xffffffff, 0x1, 0xfffffffe00000001, 0 },
+{ 0xffffffff, 0xffffffff, 0x2, 0x7fffffff00000000, 1 },
+{ 0x1ffffffff, 0xffffffff, 0x2, 0xfffffffe80000000, 1 },
+{ 0x1ffffffff, 0xffffffff, 0x3, 0xaaaaaaa9aaaaaaab, 0 },
+{ 0x1ffffffff, 0x1ffffffff, 0x4, 0xffffffff00000000, 1 },
+{ 0xffff000000000000, 0xffff000000000000, 0xffff000000000001, 0xfffeffffffffffff, 1 },
+{ 0x3333333333333333, 0x3333333333333333, 0x5555555555555555, 0x1eb851eb851eb851, 1 },
+{ 0x7fffffffffffffff, 0x2, 0x3, 0x5555555555555554, 1 },
+{ 0xffffffffffffffff, 0x2, 0x8000000000000000, 0x3, 1 },
+{ 0xffffffffffffffff, 0x2, 0xc000000000000000, 0x2, 1 },
+{ 0xffffffffffffffff, 0x4000000000000004, 0x8000000000000000, 0x8000000000000007, 1 },
+{ 0xffffffffffffffff, 0x4000000000000001, 0x8000000000000000, 0x8000000000000001, 1 },
+{ 0xffffffffffffffff, 0x8000000000000001, 0xffffffffffffffff, 0x8000000000000001, 0 },
+{ 0xfffffffffffffffe, 0x8000000000000001, 0xffffffffffffffff, 0x8000000000000000, 1 },
+{ 0xffffffffffffffff, 0x8000000000000001, 0xfffffffffffffffe, 0x8000000000000001, 1 },
+{ 0xffffffffffffffff, 0x8000000000000001, 0xfffffffffffffffd, 0x8000000000000002, 1 },
+{ 0x7fffffffffffffff, 0xffffffffffffffff, 0xc000000000000000, 0xaaaaaaaaaaaaaaa8, 1 },
+{ 0xffffffffffffffff, 0x7fffffffffffffff, 0xa000000000000000, 0xccccccccccccccca, 1 },
+{ 0xffffffffffffffff, 0x7fffffffffffffff, 0x9000000000000000, 0xe38e38e38e38e38b, 1 },
+{ 0x7fffffffffffffff, 0x7fffffffffffffff, 0x5000000000000000, 0xccccccccccccccc9, 1 },
+{ 0xffffffffffffffff, 0xfffffffffffffffe, 0xffffffffffffffff, 0xfffffffffffffffe, 0 },
+{ 0xe6102d256d7ea3ae, 0x70a77d0be4c31201, 0xd63ec35ab3220357, 0x78f8bf8cc86c6e18, 1 },
+{ 0xf53bae05cb86c6e1, 0x3847b32d2f8d32e0, 0xcfd4f55a647f403c, 0x42687f79d8998d35, 1 },
+{ 0x9951c5498f941092, 0x1f8c8bfdf287a251, 0xa3c8dc5f81ea3fe2, 0x1d887cb25900091f, 1 },
+{ 0x374fee9daa1bb2bb, 0x0d0bfbff7b8ae3ef, 0xc169337bd42d5179, 0x03bb2dbaffcbb961, 1 },
+{ 0xeac0d03ac10eeaf0, 0x89be05dfa162ed9b, 0x92bb1679a41f0e4b, 0xdc5f5cc9e270d216, 1 },
};
/*
* The above table can be verified with the following shell script:
- *
- * #!/bin/sh
- * sed -ne 's/^{ \+\(.*\), \+\(.*\), \+\(.*\), \+\(.*\) },$/\1 \2 \3 \4/p' \
- * lib/math/test_mul_u64_u64_div_u64.c |
- * while read a b c r; do
- * expected=$( printf "obase=16; ibase=16; %X * %X / %X\n" $a $b $c | bc )
- * given=$( printf "%X\n" $r )
- * if [ "$expected" = "$given" ]; then
- * echo "$a * $b / $c = $r OK"
- * else
- * echo "$a * $b / $c = $r is wrong" >&2
- * echo "should be equivalent to 0x$expected" >&2
- * exit 1
- * fi
- * done
+
+#!/bin/sh
+sed -ne 's/^{ \+\(.*\), \+\(.*\), \+\(.*\), \+\(.*\), \+\(.*\) },$/\1 \2 \3 \4 \5/p' \
+ lib/math/test_mul_u64_u64_div_u64.c |
+while read a b d r e; do
+ expected=$( printf "obase=16; ibase=16; %X * %X / %X\n" $a $b $d | bc )
+ given=$( printf "%X\n" $r )
+ if [ "$expected" = "$given" ]; then
+ echo "$a * $b / $d = $r OK"
+ else
+ echo "$a * $b / $d = $r is wrong" >&2
+ echo "should be equivalent to 0x$expected" >&2
+ exit 1
+ fi
+ expected=$( printf "obase=16; ibase=16; (%X * %X + %X) / %X\n" $a $b $((d-1)) $d | bc )
+ given=$( printf "%X\n" $((r + e)) )
+ if [ "$expected" = "$given" ]; then
+ echo "$a * $b +/ $d = $(printf '%#x' $((r + e))) OK"
+ else
+ echo "$a * $b +/ $d = $(printf '%#x' $((r + e))) is wrong" >&2
+ echo "should be equivalent to 0x$expected" >&2
+ exit 1
+ fi
+done
+
*/
static int __init test_init(void)
{
+ int errors = 0;
+ int tests = 0;
int i;
pr_info("Starting mul_u64_u64_div_u64() test\n");
@@ -72,19 +84,31 @@ static int __init test_init(void)
for (i = 0; i < ARRAY_SIZE(test_values); i++) {
u64 a = test_values[i].a;
u64 b = test_values[i].b;
- u64 c = test_values[i].c;
+ u64 d = test_values[i].d;
u64 expected_result = test_values[i].result;
- u64 result = mul_u64_u64_div_u64(a, b, c);
+ u64 result = mul_u64_u64_div_u64(a, b, d);
+ u64 result_up = mul_u64_u64_div_u64_roundup(a, b, d);
+
+ tests += 2;
if (result != expected_result) {
- pr_err("ERROR: 0x%016llx * 0x%016llx / 0x%016llx\n", a, b, c);
+ pr_err("ERROR: 0x%016llx * 0x%016llx / 0x%016llx\n", a, b, d);
pr_err("ERROR: expected result: %016llx\n", expected_result);
pr_err("ERROR: obtained result: %016llx\n", result);
+ errors++;
+ }
+ expected_result += test_values[i].round_up;
+ if (result_up != expected_result) {
+ pr_err("ERROR: 0x%016llx * 0x%016llx +/ 0x%016llx\n", a, b, d);
+ pr_err("ERROR: expected result: %016llx\n", expected_result);
+ pr_err("ERROR: obtained result: %016llx\n", result_up);
+ errors++;
}
}
- pr_info("Completed mul_u64_u64_div_u64() test\n");
- return 0;
+ pr_info("Completed mul_u64_u64_div_u64() test, %d tests, %d errors\n",
+ tests, errors);
+ return errors ? -EINVAL : 0;
}
static void __exit test_exit(void)
--
2.39.5
next prev parent reply other threads:[~2025-11-05 20:10 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-05 20:10 [PATCH v5 next 0/9] Implement mul_u64_u64_div_u64_roundup() David Laight
2025-11-05 20:10 ` [PATCH v5 next 1/9] lib: mul_u64_u64_div_u64() rename parameter 'c' to 'd' David Laight
2025-11-05 20:10 ` [PATCH v5 next 2/9] lib: mul_u64_u64_div_u64() Combine overflow and divide by zero checks David Laight
2025-11-05 20:10 ` [PATCH v5 next 3/9] lib: mul_u64_u64_div_u64() simplify check for a 64bit product David Laight
2025-11-05 20:59 ` Nicolas Pitre
2025-11-05 20:10 ` [PATCH v5 next 4/9] lib: Add mul_u64_add_u64_div_u64() and mul_u64_u64_div_u64_roundup() David Laight
2025-11-06 0:26 ` H. Peter Anvin
2025-11-06 9:52 ` David Laight
2025-11-05 20:10 ` David Laight [this message]
2025-11-05 20:10 ` [PATCH v5 next 6/9] lib: test_mul_u64_u64_div_u64: Test both generic and arch versions David Laight
2025-11-05 20:10 ` [PATCH v5 next 7/9] lib: mul_u64_u64_div_u64() optimise multiply on 32bit x86 David Laight
2025-11-05 23:45 ` H. Peter Anvin
2025-11-06 9:26 ` David Laight
2025-11-05 20:10 ` [PATCH v5 next 8/9] lib: mul_u64_u64_div_u64() Optimise the divide code David Laight
2025-11-05 20:10 ` [PATCH v5 next 9/9] lib: test_mul_u64_u64_div_u64: Test the 32bit code on 64bit David Laight
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