GNU Linux-libre 5.19-rc6-gnu
[releases.git] / lib / test_fprobe.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * test_fprobe.c - simple sanity test for fprobe
4  */
5
6 #include <linux/kernel.h>
7 #include <linux/fprobe.h>
8 #include <linux/random.h>
9 #include <kunit/test.h>
10
11 #define div_factor 3
12
13 static struct kunit *current_test;
14
15 static u32 rand1, entry_val, exit_val;
16
17 /* Use indirect calls to avoid inlining the target functions */
18 static u32 (*target)(u32 value);
19 static u32 (*target2)(u32 value);
20 static unsigned long target_ip;
21 static unsigned long target2_ip;
22
23 static noinline u32 fprobe_selftest_target(u32 value)
24 {
25         return (value / div_factor);
26 }
27
28 static noinline u32 fprobe_selftest_target2(u32 value)
29 {
30         return (value / div_factor) + 1;
31 }
32
33 static notrace void fp_entry_handler(struct fprobe *fp, unsigned long ip, struct pt_regs *regs)
34 {
35         KUNIT_EXPECT_FALSE(current_test, preemptible());
36         /* This can be called on the fprobe_selftest_target and the fprobe_selftest_target2 */
37         if (ip != target_ip)
38                 KUNIT_EXPECT_EQ(current_test, ip, target2_ip);
39         entry_val = (rand1 / div_factor);
40 }
41
42 static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip, struct pt_regs *regs)
43 {
44         unsigned long ret = regs_return_value(regs);
45
46         KUNIT_EXPECT_FALSE(current_test, preemptible());
47         if (ip != target_ip) {
48                 KUNIT_EXPECT_EQ(current_test, ip, target2_ip);
49                 KUNIT_EXPECT_EQ(current_test, ret, (rand1 / div_factor) + 1);
50         } else
51                 KUNIT_EXPECT_EQ(current_test, ret, (rand1 / div_factor));
52         KUNIT_EXPECT_EQ(current_test, entry_val, (rand1 / div_factor));
53         exit_val = entry_val + div_factor;
54 }
55
56 /* Test entry only (no rethook) */
57 static void test_fprobe_entry(struct kunit *test)
58 {
59         struct fprobe fp_entry = {
60                 .entry_handler = fp_entry_handler,
61         };
62
63         current_test = test;
64
65         /* Before register, unregister should be failed. */
66         KUNIT_EXPECT_NE(test, 0, unregister_fprobe(&fp_entry));
67         KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp_entry, "fprobe_selftest_target*", NULL));
68
69         entry_val = 0;
70         exit_val = 0;
71         target(rand1);
72         KUNIT_EXPECT_NE(test, 0, entry_val);
73         KUNIT_EXPECT_EQ(test, 0, exit_val);
74
75         entry_val = 0;
76         exit_val = 0;
77         target2(rand1);
78         KUNIT_EXPECT_NE(test, 0, entry_val);
79         KUNIT_EXPECT_EQ(test, 0, exit_val);
80
81         KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp_entry));
82 }
83
84 static void test_fprobe(struct kunit *test)
85 {
86         struct fprobe fp = {
87                 .entry_handler = fp_entry_handler,
88                 .exit_handler = fp_exit_handler,
89         };
90
91         current_test = test;
92         KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp, "fprobe_selftest_target*", NULL));
93
94         entry_val = 0;
95         exit_val = 0;
96         target(rand1);
97         KUNIT_EXPECT_NE(test, 0, entry_val);
98         KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
99
100         entry_val = 0;
101         exit_val = 0;
102         target2(rand1);
103         KUNIT_EXPECT_NE(test, 0, entry_val);
104         KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
105
106         KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
107 }
108
109 static void test_fprobe_syms(struct kunit *test)
110 {
111         static const char *syms[] = {"fprobe_selftest_target", "fprobe_selftest_target2"};
112         struct fprobe fp = {
113                 .entry_handler = fp_entry_handler,
114                 .exit_handler = fp_exit_handler,
115         };
116
117         current_test = test;
118         KUNIT_EXPECT_EQ(test, 0, register_fprobe_syms(&fp, syms, 2));
119
120         entry_val = 0;
121         exit_val = 0;
122         target(rand1);
123         KUNIT_EXPECT_NE(test, 0, entry_val);
124         KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
125
126         entry_val = 0;
127         exit_val = 0;
128         target2(rand1);
129         KUNIT_EXPECT_NE(test, 0, entry_val);
130         KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
131
132         KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
133 }
134
135 static unsigned long get_ftrace_location(void *func)
136 {
137         unsigned long size, addr = (unsigned long)func;
138
139         if (!kallsyms_lookup_size_offset(addr, &size, NULL) || !size)
140                 return 0;
141
142         return ftrace_location_range(addr, addr + size - 1);
143 }
144
145 static int fprobe_test_init(struct kunit *test)
146 {
147         do {
148                 rand1 = prandom_u32();
149         } while (rand1 <= div_factor);
150
151         target = fprobe_selftest_target;
152         target2 = fprobe_selftest_target2;
153         target_ip = get_ftrace_location(target);
154         target2_ip = get_ftrace_location(target2);
155
156         return 0;
157 }
158
159 static struct kunit_case fprobe_testcases[] = {
160         KUNIT_CASE(test_fprobe_entry),
161         KUNIT_CASE(test_fprobe),
162         KUNIT_CASE(test_fprobe_syms),
163         {}
164 };
165
166 static struct kunit_suite fprobe_test_suite = {
167         .name = "fprobe_test",
168         .init = fprobe_test_init,
169         .test_cases = fprobe_testcases,
170 };
171
172 kunit_test_suites(&fprobe_test_suite);
173
174 MODULE_LICENSE("GPL");