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percpu: add a test case for the specific 64-bit value addition

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It might be a corner case when we add UINT_MAX as 64-bit unsigned value to
the percpu variable as it's not the same as -1 (ULONG_LONG_MAX).  Add a
test case for that.

Link: https://lkml.kernel.org/r/20241016182635.1156168-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Andy Shevchenko 2024-10-16 21:23:52 +03:00 committed by Andrew Morton
parent 6c2625e9c2
commit 4a7bba1df0
1 changed files with 10 additions and 1 deletions
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11
lib/percpu_test.c
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@ -1,4 +1,5 @@
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/limits.h>
#include <linux/module.h>
/* validate @native and @pcp counter values match @expected */
@ -24,8 +25,9 @@ static int __init percpu_test_init(void)
* +ul_one/-ul_one below would replace with inc/dec instructions.
*/
volatile unsigned int ui_one = 1;
long l = 0;
unsigned long long ull = 0;
unsigned long ul = 0;
long l = 0;
pr_info("percpu test start\n");
@ -112,6 +114,13 @@ static int __init percpu_test_init(void)
CHECK(ul, ulong_counter, -1);
CHECK(ul, ulong_counter, ULONG_MAX);
ul = ull = 0;
__this_cpu_write(ulong_counter, 0);
ul = ull += UINT_MAX;
__this_cpu_add(ulong_counter, ull);
CHECK(ul, ulong_counter, UINT_MAX);
ul = 3;
__this_cpu_write(ulong_counter, 3);