[linux.git] / lib / percpu_test.c

// SPDX-License-Identifier: GPL-2.0-only
#include <linux/module.h>

/* validate @native and @pcp counter values match @expected */
#define CHECK(native, pcp, expected)                                    \
	do {                                                            \
		WARN((native) != (expected),                            \
		     "raw %ld (0x%lx) != expected %lld (0x%llx)",	\
		     (native), (native),				\
		     (long long)(expected), (long long)(expected));	\
		WARN(__this_cpu_read(pcp) != (expected),                \
		     "pcp %ld (0x%lx) != expected %lld (0x%llx)",	\
		     __this_cpu_read(pcp), __this_cpu_read(pcp),	\
		     (long long)(expected), (long long)(expected));	\
	} while (0)

static DEFINE_PER_CPU(long, long_counter);
static DEFINE_PER_CPU(unsigned long, ulong_counter);

static int __init percpu_test_init(void)
{
	/*
	 * volatile prevents compiler from optimizing it uses, otherwise the
	 * +ul_one/-ul_one below would replace with inc/dec instructions.
	 */
	volatile unsigned int ui_one = 1;
	long l = 0;
	unsigned long ul = 0;

	pr_info("percpu test start\n");

	preempt_disable();

	l += -1;
	__this_cpu_add(long_counter, -1);
	CHECK(l, long_counter, -1);

	l += 1;
	__this_cpu_add(long_counter, 1);
	CHECK(l, long_counter, 0);

	ul = 0;
	__this_cpu_write(ulong_counter, 0);

	ul += 1UL;
	__this_cpu_add(ulong_counter, 1UL);
	CHECK(ul, ulong_counter, 1);

	ul += -1UL;
	__this_cpu_add(ulong_counter, -1UL);
	CHECK(ul, ulong_counter, 0);

	ul += -(unsigned long)1;
	__this_cpu_add(ulong_counter, -(unsigned long)1);
	CHECK(ul, ulong_counter, -1);

	ul = 0;
	__this_cpu_write(ulong_counter, 0);

	ul -= 1;
	__this_cpu_dec(ulong_counter);
	CHECK(ul, ulong_counter, -1);
	CHECK(ul, ulong_counter, ULONG_MAX);

	l += -ui_one;
	__this_cpu_add(long_counter, -ui_one);
	CHECK(l, long_counter, 0xffffffff);

	l += ui_one;
	__this_cpu_add(long_counter, ui_one);
	CHECK(l, long_counter, (long)0x100000000LL);


	l = 0;
	__this_cpu_write(long_counter, 0);

	l -= ui_one;
	__this_cpu_sub(long_counter, ui_one);
	CHECK(l, long_counter, -1);

	l = 0;
	__this_cpu_write(long_counter, 0);

	l += ui_one;
	__this_cpu_add(long_counter, ui_one);
	CHECK(l, long_counter, 1);

	l += -ui_one;
	__this_cpu_add(long_counter, -ui_one);
	CHECK(l, long_counter, (long)0x100000000LL);

	l = 0;
	__this_cpu_write(long_counter, 0);

	l -= ui_one;
	this_cpu_sub(long_counter, ui_one);
	CHECK(l, long_counter, -1);
	CHECK(l, long_counter, ULONG_MAX);

	ul = 0;
	__this_cpu_write(ulong_counter, 0);

	ul += ui_one;
	__this_cpu_add(ulong_counter, ui_one);
	CHECK(ul, ulong_counter, 1);

	ul = 0;
	__this_cpu_write(ulong_counter, 0);

	ul -= ui_one;
	__this_cpu_sub(ulong_counter, ui_one);
	CHECK(ul, ulong_counter, -1);
	CHECK(ul, ulong_counter, ULONG_MAX);

	ul = 3;
	__this_cpu_write(ulong_counter, 3);

	ul = this_cpu_sub_return(ulong_counter, ui_one);
	CHECK(ul, ulong_counter, 2);

	ul = __this_cpu_sub_return(ulong_counter, ui_one);
	CHECK(ul, ulong_counter, 1);

	preempt_enable();

	pr_info("percpu test done\n");
	return -EAGAIN;  /* Fail will directly unload the module */
}

static void __exit percpu_test_exit(void)
{
}

module_init(percpu_test_init)
module_exit(percpu_test_exit)

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Greg Thelen");
MODULE_DESCRIPTION("percpu operations test");
Commit	Line	Data
09c434b8	1	// SPDX-License-Identifier: GPL-2.0-only
623fd807 GT	2	#include <linux/module.h>
	3
	4	/* validate @native and @pcp counter values match @expected */
	5	#define CHECK(native, pcp, expected) \
	6	do { \
	7	WARN((native) != (expected), \
	8	"raw %ld (0x%lx) != expected %lld (0x%llx)", \
	9	(native), (native), \
	10	(long long)(expected), (long long)(expected)); \
	11	WARN(__this_cpu_read(pcp) != (expected), \
	12	"pcp %ld (0x%lx) != expected %lld (0x%llx)", \
	13	__this_cpu_read(pcp), __this_cpu_read(pcp), \
	14	(long long)(expected), (long long)(expected)); \
	15	} while (0)
	16
	17	static DEFINE_PER_CPU(long, long_counter);
	18	static DEFINE_PER_CPU(unsigned long, ulong_counter);
	19
	20	static int __init percpu_test_init(void)
	21	{
	22	/*
	23	* volatile prevents compiler from optimizing it uses, otherwise the
	24	* +ul_one/-ul_one below would replace with inc/dec instructions.
	25	*/
	26	volatile unsigned int ui_one = 1;
	27	long l = 0;
	28	unsigned long ul = 0;
	29
	30	pr_info("percpu test start\n");
	31
	32	preempt_disable();
	33
	34	l += -1;
	35	__this_cpu_add(long_counter, -1);
	36	CHECK(l, long_counter, -1);
	37
	38	l += 1;
	39	__this_cpu_add(long_counter, 1);
	40	CHECK(l, long_counter, 0);
	41
	42	ul = 0;
	43	__this_cpu_write(ulong_counter, 0);
	44
	45	ul += 1UL;
	46	__this_cpu_add(ulong_counter, 1UL);
	47	CHECK(ul, ulong_counter, 1);
	48
	49	ul += -1UL;
	50	__this_cpu_add(ulong_counter, -1UL);
	51	CHECK(ul, ulong_counter, 0);
	52
	53	ul += -(unsigned long)1;
	54	__this_cpu_add(ulong_counter, -(unsigned long)1);
	55	CHECK(ul, ulong_counter, -1);
	56
	57	ul = 0;
	58	__this_cpu_write(ulong_counter, 0);
	59
	60	ul -= 1;
	61	__this_cpu_dec(ulong_counter);
	62	CHECK(ul, ulong_counter, -1);
	63	CHECK(ul, ulong_counter, ULONG_MAX);
	64
	65	l += -ui_one;
66	__this_cpu_add(long_counter, -ui_one);
67	CHECK(l, long_counter, 0xffffffff);
68
69	l += ui_one;
70	__this_cpu_add(long_counter, ui_one);
71	CHECK(l, long_counter, (long)0x100000000LL);
72
73
74	l = 0;
75	__this_cpu_write(long_counter, 0);
76
77	l -= ui_one;
78	__this_cpu_sub(long_counter, ui_one);
79	CHECK(l, long_counter, -1);
80
81	l = 0;
82	__this_cpu_write(long_counter, 0);
83
84	l += ui_one;
85	__this_cpu_add(long_counter, ui_one);
86	CHECK(l, long_counter, 1);
87
88	l += -ui_one;
89	__this_cpu_add(long_counter, -ui_one);
90	CHECK(l, long_counter, (long)0x100000000LL);
91
92	l = 0;
93	__this_cpu_write(long_counter, 0);
94
95	l -= ui_one;
96	this_cpu_sub(long_counter, ui_one);
97	CHECK(l, long_counter, -1);
98	CHECK(l, long_counter, ULONG_MAX);
99
100	ul = 0;
101	__this_cpu_write(ulong_counter, 0);
102
103	ul += ui_one;
104	__this_cpu_add(ulong_counter, ui_one);
105	CHECK(ul, ulong_counter, 1);
106
107	ul = 0;
108	__this_cpu_write(ulong_counter, 0);
109
110	ul -= ui_one;
111	__this_cpu_sub(ulong_counter, ui_one);
112	CHECK(ul, ulong_counter, -1);
113	CHECK(ul, ulong_counter, ULONG_MAX);
114
115	ul = 3;
116	__this_cpu_write(ulong_counter, 3);
117
118	ul = this_cpu_sub_return(ulong_counter, ui_one);
119	CHECK(ul, ulong_counter, 2);
120
121	ul = __this_cpu_sub_return(ulong_counter, ui_one);
122	CHECK(ul, ulong_counter, 1);
123
124	preempt_enable();
125
126	pr_info("percpu test done\n");
127	return -EAGAIN; /* Fail will directly unload the module */
128	}
129
130	static void __exit percpu_test_exit(void)
131	{
132	}
133
134	module_init(percpu_test_init)
135	module_exit(percpu_test_exit)
136
137	MODULE_LICENSE("GPL");
138	MODULE_AUTHOR("Greg Thelen");
139	MODULE_DESCRIPTION("percpu operations test");