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| author | Andy Shevchenko <andriy.shevchenko@linux.intel.com> | 2024-10-16 21:23:52 +0300 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-11-06 20:11:14 -0800 |
| commit | 4a7bba1df00163ecbdf4994bc42b879ade4aeed2 (patch) | |
| tree | 1683da685f144f90a5f3c5d6514cdf6882349fda | |
| parent | 6c2625e9c2efef5272e1addf6007a1fcab1f059b (diff) | |
| download | lwn-4a7bba1df00163ecbdf4994bc42b879ade4aeed2.tar.gz lwn-4a7bba1df00163ecbdf4994bc42b879ade4aeed2.zip | |
percpu: add a test case for the specific 64-bit value addition
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>
| -rw-r--r-- | lib/percpu_test.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/lib/percpu_test.c b/lib/percpu_test.c index 4a3d70bbc1a0..ce7124b16dab 100644 --- a/lib/percpu_test.c +++ b/lib/percpu_test.c @@ -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); |