lib: test_mul_u64_u64_div_u64(): test the 32bit code on 64bit

There are slight differences in the mul_u64_add_u64_div_u64() code between
32bit and 64bit systems.

Compile and test the 32bit version on 64bit hosts for better test
coverage.

Link: https://lkml.kernel.org/r/20251105201035.64043-10-david.laight.linux@gmail.com
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Reviewed-by: Nicolas Pitre <npitre@baylibre.com>
Cc: Biju Das <biju.das.jz@bp.renesas.com>
Cc: Borislav Betkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Li RongQing <lirongqing@baidu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/lib/math/test_mul_u64_u64_div_u64.c b/lib/math/test_mul_u64_u64_div_u64.c
index d8d2c18c46144d13b362fed397cc33de14ccea69..338d014f0c733027a9a78c9d8c76baede6690b84 100644 (file)
--- a/lib/math/test_mul_u64_u64_div_u64.c
+++ b/lib/math/test_mul_u64_u64_div_u64.c
@@ -74,6 +74,10 @@ done
  */
 
 static u64 test_mul_u64_add_u64_div_u64(u64 a, u64 b, u64 c, u64 d);
+#if __LONG_WIDTH__ >= 64
+#define TEST_32BIT_DIV
+static u64 test_mul_u64_add_u64_div_u64_32bit(u64 a, u64 b, u64 c, u64 d);
+#endif
 
 static int __init test_run(unsigned int fn_no, const char *fn_name)
 {
@@ -100,6 +104,12 @@ static int __init test_run(unsigned int fn_no, const char *fn_name)
                        result = test_mul_u64_add_u64_div_u64(a, b, 0, d);
                        result_up = test_mul_u64_add_u64_div_u64(a, b, d - 1, d);
                        break;
+#ifdef TEST_32BIT_DIV
+               case 2:
+                       result = test_mul_u64_add_u64_div_u64_32bit(a, b, 0, d);
+                       result_up = test_mul_u64_add_u64_div_u64_32bit(a, b, d - 1, d);
+                       break;
+#endif
                }
 
                tests += 2;
@@ -131,6 +141,10 @@ static int __init test_init(void)
                return -EINVAL;
        if (test_run(1, "test_mul_u64_u64_div_u64"))
                return -EINVAL;
+#ifdef TEST_32BIT_DIV
+       if (test_run(2, "test_mul_u64_u64_div_u64_32bit"))
+               return -EINVAL;
+#endif
        return 0;
 }
 
@@ -153,6 +167,21 @@ static void __exit test_exit(void)
 
 #include "div64.c"
 
+#ifdef TEST_32BIT_DIV
+/* Recompile the generic code for 32bit long */
+#undef test_mul_u64_add_u64_div_u64
+#define test_mul_u64_add_u64_div_u64 test_mul_u64_add_u64_div_u64_32bit
+#undef BITS_PER_ITER
+#define BITS_PER_ITER 16
+
+#define mul_u64_u64_add_u64 mul_u64_u64_add_u64_32bit
+#undef mul_u64_long_add_u64
+#undef add_u64_long
+#undef mul_add
+
+#include "div64.c"
+#endif
+
 module_init(test_init);
 module_exit(test_exit);