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#define pr_fmt(fmt) "Kprobe smoke test: " fmt
18
19#include <linux/kernel.h>
20#include <linux/kprobes.h>
21#include <linux/random.h>
22
23#define div_factor 3
24
25static u32 rand1, preh_val, posth_val, jph_val;
26static int errors, handler_errors, num_tests;
27static u32 (*target)(u32 value);
28static u32 (*target2)(u32 value);
29
30static noinline u32 kprobe_target(u32 value)
31{
32	return (value / div_factor);
33}
34
35static int kp_pre_handler(struct kprobe *p, struct pt_regs *regs)
36{
37	preh_val = (rand1 / div_factor);
38	return 0;
39}
40
41static void kp_post_handler(struct kprobe *p, struct pt_regs *regs,
42		unsigned long flags)
43{
44	if (preh_val != (rand1 / div_factor)) {
45		handler_errors++;
46		pr_err("incorrect value in post_handler\n");
47	}
48	posth_val = preh_val + div_factor;
49}
50
51static struct kprobe kp = {
52	.symbol_name = "kprobe_target",
53	.pre_handler = kp_pre_handler,
54	.post_handler = kp_post_handler
55};
56
57static int test_kprobe(void)
58{
59	int ret;
60
61	ret = register_kprobe(&kp);
62	if (ret < 0) {
63		pr_err("register_kprobe returned %d\n", ret);
64		return ret;
65	}
66
67	ret = target(rand1);
68	unregister_kprobe(&kp);
69
70	if (preh_val == 0) {
71		pr_err("kprobe pre_handler not called\n");
72		handler_errors++;
73	}
74
75	if (posth_val == 0) {
76		pr_err("kprobe post_handler not called\n");
77		handler_errors++;
78	}
79
80	return 0;
81}
82
83static noinline u32 kprobe_target2(u32 value)
84{
85	return (value / div_factor) + 1;
86}
87
88static int kp_pre_handler2(struct kprobe *p, struct pt_regs *regs)
89{
90	preh_val = (rand1 / div_factor) + 1;
91	return 0;
92}
93
94static void kp_post_handler2(struct kprobe *p, struct pt_regs *regs,
95		unsigned long flags)
96{
97	if (preh_val != (rand1 / div_factor) + 1) {
98		handler_errors++;
99		pr_err("incorrect value in post_handler2\n");
100	}
101	posth_val = preh_val + div_factor;
102}
103
104static struct kprobe kp2 = {
105	.symbol_name = "kprobe_target2",
106	.pre_handler = kp_pre_handler2,
107	.post_handler = kp_post_handler2
108};
109
110static int test_kprobes(void)
111{
112	int ret;
113	struct kprobe *kps[2] = {&kp, &kp2};
114
115	/* addr and flags should be cleard for reusing kprobe. */
116	kp.addr = NULL;
117	kp.flags = 0;
118	ret = register_kprobes(kps, 2);
119	if (ret < 0) {
120		pr_err("register_kprobes returned %d\n", ret);
121		return ret;
122	}
123
124	preh_val = 0;
125	posth_val = 0;
126	ret = target(rand1);
127
128	if (preh_val == 0) {
129		pr_err("kprobe pre_handler not called\n");
130		handler_errors++;
131	}
132
133	if (posth_val == 0) {
134		pr_err("kprobe post_handler not called\n");
135		handler_errors++;
136	}
137
138	preh_val = 0;
139	posth_val = 0;
140	ret = target2(rand1);
141
142	if (preh_val == 0) {
143		pr_err("kprobe pre_handler2 not called\n");
144		handler_errors++;
145	}
146
147	if (posth_val == 0) {
148		pr_err("kprobe post_handler2 not called\n");
149		handler_errors++;
150	}
151
152	unregister_kprobes(kps, 2);
153	return 0;
154
155}
156
157static u32 j_kprobe_target(u32 value)
158{
159	if (value != rand1) {
160		handler_errors++;
161		pr_err("incorrect value in jprobe handler\n");
162	}
163
164	jph_val = rand1;
165	jprobe_return();
166	return 0;
167}
168
169static struct jprobe jp = {
170	.entry		= j_kprobe_target,
171	.kp.symbol_name = "kprobe_target"
172};
173
174static int test_jprobe(void)
175{
176	int ret;
177
178	ret = register_jprobe(&jp);
179	if (ret < 0) {
180		pr_err("register_jprobe returned %d\n", ret);
181		return ret;
182	}
183
184	ret = target(rand1);
185	unregister_jprobe(&jp);
186	if (jph_val == 0) {
187		pr_err("jprobe handler not called\n");
188		handler_errors++;
189	}
190
191	return 0;
192}
193
194static struct jprobe jp2 = {
195	.entry          = j_kprobe_target,
196	.kp.symbol_name = "kprobe_target2"
197};
198
199static int test_jprobes(void)
200{
201	int ret;
202	struct jprobe *jps[2] = {&jp, &jp2};
203
204	/* addr and flags should be cleard for reusing kprobe. */
205	jp.kp.addr = NULL;
206	jp.kp.flags = 0;
207	ret = register_jprobes(jps, 2);
208	if (ret < 0) {
209		pr_err("register_jprobes returned %d\n", ret);
210		return ret;
211	}
212
213	jph_val = 0;
214	ret = target(rand1);
215	if (jph_val == 0) {
216		pr_err("jprobe handler not called\n");
217		handler_errors++;
218	}
219
220	jph_val = 0;
221	ret = target2(rand1);
222	if (jph_val == 0) {
223		pr_err("jprobe handler2 not called\n");
224		handler_errors++;
225	}
226	unregister_jprobes(jps, 2);
227
228	return 0;
229}
230#ifdef CONFIG_KRETPROBES
231static u32 krph_val;
232
233static int entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
234{
235	krph_val = (rand1 / div_factor);
236	return 0;
237}
238
239static int return_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
240{
241	unsigned long ret = regs_return_value(regs);
242
243	if (ret != (rand1 / div_factor)) {
244		handler_errors++;
245		pr_err("incorrect value in kretprobe handler\n");
246	}
247	if (krph_val == 0) {
248		handler_errors++;
249		pr_err("call to kretprobe entry handler failed\n");
250	}
251
252	krph_val = rand1;
253	return 0;
254}
255
256static struct kretprobe rp = {
257	.handler	= return_handler,
258	.entry_handler  = entry_handler,
259	.kp.symbol_name = "kprobe_target"
260};
261
262static int test_kretprobe(void)
263{
264	int ret;
265
266	ret = register_kretprobe(&rp);
267	if (ret < 0) {
268		pr_err("register_kretprobe returned %d\n", ret);
269		return ret;
270	}
271
272	ret = target(rand1);
273	unregister_kretprobe(&rp);
274	if (krph_val != rand1) {
275		pr_err("kretprobe handler not called\n");
276		handler_errors++;
277	}
278
279	return 0;
280}
281
282static int return_handler2(struct kretprobe_instance *ri, struct pt_regs *regs)
283{
284	unsigned long ret = regs_return_value(regs);
285
286	if (ret != (rand1 / div_factor) + 1) {
287		handler_errors++;
288		pr_err("incorrect value in kretprobe handler2\n");
289	}
290	if (krph_val == 0) {
291		handler_errors++;
292		pr_err("call to kretprobe entry handler failed\n");
293	}
294
295	krph_val = rand1;
296	return 0;
297}
298
299static struct kretprobe rp2 = {
300	.handler	= return_handler2,
301	.entry_handler  = entry_handler,
302	.kp.symbol_name = "kprobe_target2"
303};
304
305static int test_kretprobes(void)
306{
307	int ret;
308	struct kretprobe *rps[2] = {&rp, &rp2};
309
310	/* addr and flags should be cleard for reusing kprobe. */
311	rp.kp.addr = NULL;
312	rp.kp.flags = 0;
313	ret = register_kretprobes(rps, 2);
314	if (ret < 0) {
315		pr_err("register_kretprobe returned %d\n", ret);
316		return ret;
317	}
318
319	krph_val = 0;
320	ret = target(rand1);
321	if (krph_val != rand1) {
322		pr_err("kretprobe handler not called\n");
323		handler_errors++;
324	}
325
326	krph_val = 0;
327	ret = target2(rand1);
328	if (krph_val != rand1) {
329		pr_err("kretprobe handler2 not called\n");
330		handler_errors++;
331	}
332	unregister_kretprobes(rps, 2);
333	return 0;
334}
335#endif /* CONFIG_KRETPROBES */
336
337int init_test_probes(void)
338{
339	int ret;
340
341	target = kprobe_target;
342	target2 = kprobe_target2;
343
344	do {
345		rand1 = prandom_u32();
346	} while (rand1 <= div_factor);
347
348	pr_info("started\n");
349	num_tests++;
350	ret = test_kprobe();
351	if (ret < 0)
352		errors++;
353
354	num_tests++;
355	ret = test_kprobes();
356	if (ret < 0)
357		errors++;
358
359	num_tests++;
360	ret = test_jprobe();
361	if (ret < 0)
362		errors++;
363
364	num_tests++;
365	ret = test_jprobes();
366	if (ret < 0)
367		errors++;
368
369#ifdef CONFIG_KRETPROBES
370	num_tests++;
371	ret = test_kretprobe();
372	if (ret < 0)
373		errors++;
374
375	num_tests++;
376	ret = test_kretprobes();
377	if (ret < 0)
378		errors++;
379#endif /* CONFIG_KRETPROBES */
380
381	if (errors)
382		pr_err("BUG: %d out of %d tests failed\n", errors, num_tests);
383	else if (handler_errors)
384		pr_err("BUG: %d error(s) running handlers\n", handler_errors);
385	else
386		pr_info("passed successfully\n");
387
388	return 0;
389}
390