1 /*
2 * test_kprobes.c - simple sanity test for *probes
3 *
4 * Copyright IBM Corp. 2008
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it would be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
14 * the GNU General Public License for more details.
15 */
16
17 #include <linux/kernel.h>
18 #include <linux/kprobes.h>
19 #include <linux/random.h>
20
21 #define div_factor 3
22
23 static u32 rand1, preh_val, posth_val, jph_val;
24 static int errors, handler_errors, num_tests;
25
26 static noinline u32 kprobe_target(u32 value)
27 {
28 /*
29 * gcc ignores noinline on some architectures unless we stuff
30 * sufficient lard into the function. The get_kprobe() here is
31 * just for that.
32 *
33 * NOTE: We aren't concerned about the correctness of get_kprobe()
34 * here; hence, this call is neither under !preempt nor with the
35 * kprobe_mutex held. This is fine(tm)
36 */
37 if (get_kprobe((void *)0xdeadbeef))
38 printk(KERN_INFO "Kprobe smoke test: probe on 0xdeadbeef!\n");
39
40 return (value / div_factor);
41 }
42
43 static int kp_pre_handler(struct kprobe *p, struct pt_regs *regs)
44 {
45 preh_val = (rand1 / div_factor);
46 return 0;
47 }
48
49 static void kp_post_handler(struct kprobe *p, struct pt_regs *regs,
50 unsigned long flags)
51 {
52 if (preh_val != (rand1 / div_factor)) {
53 handler_errors++;
54 printk(KERN_ERR "Kprobe smoke test failed: "
55 "incorrect value in post_handler\n");
56 }
57 posth_val = preh_val + div_factor;
58 }
59
60 static struct kprobe kp = {
61 .symbol_name = "kprobe_target",
62 .pre_handler = kp_pre_handler,
63 .post_handler = kp_post_handler
64 };
65
66 static int test_kprobe(void)
67 {
68 int ret;
69
70 ret = register_kprobe(&kp);
71 if (ret < 0) {
72 printk(KERN_ERR "Kprobe smoke test failed: "
73 "register_kprobe returned %d\n", ret);
74 return ret;
75 }
76
77 ret = kprobe_target(rand1);
78 unregister_kprobe(&kp);
79
80 if (preh_val == 0) {
81 printk(KERN_ERR "Kprobe smoke test failed: "
82 "kprobe pre_handler not called\n");
83 handler_errors++;
84 }
85
86 if (posth_val == 0) {
87 printk(KERN_ERR "Kprobe smoke test failed: "
88 "kprobe post_handler not called\n");
89 handler_errors++;
90 }
91
92 return 0;
93 }
94
95 static u32 j_kprobe_target(u32 value)
96 {
97 if (value != rand1) {
98 handler_errors++;
99 printk(KERN_ERR "Kprobe smoke test failed: "
100 "incorrect value in jprobe handler\n");
101 }
102
103 jph_val = rand1;
104 jprobe_return();
105 return 0;
106 }
107
108 static struct jprobe jp = {
109 .entry = j_kprobe_target,
110 .kp.symbol_name = "kprobe_target"
111 };
112
113 static int test_jprobe(void)
114 {
115 int ret;
116
117 ret = register_jprobe(&jp);
118 if (ret < 0) {
119 printk(KERN_ERR "Kprobe smoke test failed: "
120 "register_jprobe returned %d\n", ret);
121 return ret;
122 }
123
124 ret = kprobe_target(rand1);
125 unregister_jprobe(&jp);
126 if (jph_val == 0) {
127 printk(KERN_ERR "Kprobe smoke test failed: "
128 "jprobe handler not called\n");
129 handler_errors++;
130 }
131
132 return 0;
133 }
134
135 #ifdef CONFIG_KRETPROBES
136 static u32 krph_val;
137
138 static int entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
139 {
140 krph_val = (rand1 / div_factor);
141 return 0;
142 }
143
144 static int return_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
145 {
146 unsigned long ret = regs_return_value(regs);
147
148 if (ret != (rand1 / div_factor)) {
149 handler_errors++;
150 printk(KERN_ERR "Kprobe smoke test failed: "
151 "incorrect value in kretprobe handler\n");
152 }
153 if (krph_val == 0) {
154 handler_errors++;
155 printk(KERN_ERR "Kprobe smoke test failed: "
156 "call to kretprobe entry handler failed\n");
157 }
158
159 krph_val = rand1;
160 return 0;
161 }
162
163 static struct kretprobe rp = {
164 .handler = return_handler,
165 .entry_handler = entry_handler,
166 .kp.symbol_name = "kprobe_target"
167 };
168
169 static int test_kretprobe(void)
170 {
171 int ret;
172
173 ret = register_kretprobe(&rp);
174 if (ret < 0) {
175 printk(KERN_ERR "Kprobe smoke test failed: "
176 "register_kretprobe returned %d\n", ret);
177 return ret;
178 }
179
180 ret = kprobe_target(rand1);
181 unregister_kretprobe(&rp);
182 if (krph_val != rand1) {
183 printk(KERN_ERR "Kprobe smoke test failed: "
184 "kretprobe handler not called\n");
185 handler_errors++;
186 }
187
188 return 0;
189 }
190 #endif /* CONFIG_KRETPROBES */
191
192 int init_test_probes(void)
193 {
194 int ret;
195
196 do {
197 rand1 = random32();
198 } while (rand1 <= div_factor);
199
200 printk(KERN_INFO "Kprobe smoke test started\n");
201 num_tests++;
202 ret = test_kprobe();
203 if (ret < 0)
204 errors++;
205
206 num_tests++;
207 ret = test_jprobe();
208 if (ret < 0)
209 errors++;
210
211 #ifdef CONFIG_KRETPROBES
212 num_tests++;
213 ret = test_kretprobe();
214 if (ret < 0)
215 errors++;
216 #endif /* CONFIG_KRETPROBES */
217
218 if (errors)
219 printk(KERN_ERR "BUG: Kprobe smoke test: %d out of "
220 "%d tests failed\n", errors, num_tests);
221 else if (handler_errors)
222 printk(KERN_ERR "BUG: Kprobe smoke test: %d error(s) "
223 "running handlers\n", handler_errors);
224 else
225 printk(KERN_INFO "Kprobe smoke test passed successfully\n");
226
227 return 0;
228 }
229
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