summaryrefslogtreecommitdiff
path: root/tools/perf/arch/x86/tests/bp-modify.c
blob: adcacf1b6609e68a9e8024b827d06c706b779f5b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
// SPDX-License-Identifier: GPL-2.0
#include <linux/compiler.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/user.h>
#include <syscall.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ptrace.h>
#include <asm/ptrace.h>
#include <errno.h>
#include "debug.h"
#include "tests/tests.h"
#include "arch-tests.h"

static noinline int bp_1(void)
{
	pr_debug("in %s\n", __func__);
	return 0;
}

static noinline int bp_2(void)
{
	pr_debug("in %s\n", __func__);
	return 0;
}

static int spawn_child(void)
{
	int child = fork();

	if (child == 0) {
		/*
		 * The child sets itself for as tracee and
		 * waits in signal for parent to trace it,
		 * then it calls bp_1 and quits.
		 */
		int err = ptrace(PTRACE_TRACEME, 0, NULL, NULL);

		if (err) {
			pr_debug("failed to PTRACE_TRACEME\n");
			exit(1);
		}

		raise(SIGCONT);
		bp_1();
		exit(0);
	}

	return child;
}

/*
 * This tests creates HW breakpoint, tries to
 * change it and checks it was properly changed.
 */
static int bp_modify1(void)
{
	pid_t child;
	int status;
	unsigned long rip = 0, dr7 = 1;

	child = spawn_child();

	waitpid(child, &status, 0);
	if (WIFEXITED(status)) {
		pr_debug("tracee exited prematurely 1\n");
		return TEST_FAIL;
	}

	/*
	 * The parent does following steps:
	 *  - creates a new breakpoint (id 0) for bp_2 function
	 *  - changes that breakponit to bp_1 function
	 *  - waits for the breakpoint to hit and checks
	 *    it has proper rip of bp_1 function
	 *  - detaches the child
	 */
	if (ptrace(PTRACE_POKEUSER, child,
		   offsetof(struct user, u_debugreg[0]), bp_2)) {
		pr_debug("failed to set breakpoint, 1st time: %s\n",
			 strerror(errno));
		goto out;
	}

	if (ptrace(PTRACE_POKEUSER, child,
		   offsetof(struct user, u_debugreg[0]), bp_1)) {
		pr_debug("failed to set breakpoint, 2nd time: %s\n",
			 strerror(errno));
		goto out;
	}

	if (ptrace(PTRACE_POKEUSER, child,
		   offsetof(struct user, u_debugreg[7]), dr7)) {
		pr_debug("failed to set dr7: %s\n", strerror(errno));
		goto out;
	}

	if (ptrace(PTRACE_CONT, child, NULL, NULL)) {
		pr_debug("failed to PTRACE_CONT: %s\n", strerror(errno));
		goto out;
	}

	waitpid(child, &status, 0);
	if (WIFEXITED(status)) {
		pr_debug("tracee exited prematurely 2\n");
		return TEST_FAIL;
	}

	rip = ptrace(PTRACE_PEEKUSER, child,
		     offsetof(struct user_regs_struct, rip), NULL);
	if (rip == (unsigned long) -1) {
		pr_debug("failed to PTRACE_PEEKUSER: %s\n",
			 strerror(errno));
		goto out;
	}

	pr_debug("rip %lx, bp_1 %p\n", rip, bp_1);

out:
	if (ptrace(PTRACE_DETACH, child, NULL, NULL)) {
		pr_debug("failed to PTRACE_DETACH: %s", strerror(errno));
		return TEST_FAIL;
	}

	return rip == (unsigned long) bp_1 ? TEST_OK : TEST_FAIL;
}

/*
 * This tests creates HW breakpoint, tries to
 * change it to bogus value and checks the original
 * breakpoint is hit.
 */
static int bp_modify2(void)
{
	pid_t child;
	int status;
	unsigned long rip = 0, dr7 = 1;

	child = spawn_child();

	waitpid(child, &status, 0);
	if (WIFEXITED(status)) {
		pr_debug("tracee exited prematurely 1\n");
		return TEST_FAIL;
	}

	/*
	 * The parent does following steps:
	 *  - creates a new breakpoint (id 0) for bp_1 function
	 *  - tries to change that breakpoint to (-1) address
	 *  - waits for the breakpoint to hit and checks
	 *    it has proper rip of bp_1 function
	 *  - detaches the child
	 */
	if (ptrace(PTRACE_POKEUSER, child,
		   offsetof(struct user, u_debugreg[0]), bp_1)) {
		pr_debug("failed to set breakpoint: %s\n",
			 strerror(errno));
		goto out;
	}

	if (ptrace(PTRACE_POKEUSER, child,
		   offsetof(struct user, u_debugreg[7]), dr7)) {
		pr_debug("failed to set dr7: %s\n", strerror(errno));
		goto out;
	}

	if (!ptrace(PTRACE_POKEUSER, child,
		   offsetof(struct user, u_debugreg[0]), (unsigned long) (-1))) {
		pr_debug("failed, breakpoint set to bogus address\n");
		goto out;
	}

	if (ptrace(PTRACE_CONT, child, NULL, NULL)) {
		pr_debug("failed to PTRACE_CONT: %s\n", strerror(errno));
		goto out;
	}

	waitpid(child, &status, 0);
	if (WIFEXITED(status)) {
		pr_debug("tracee exited prematurely 2\n");
		return TEST_FAIL;
	}

	rip = ptrace(PTRACE_PEEKUSER, child,
		     offsetof(struct user_regs_struct, rip), NULL);
	if (rip == (unsigned long) -1) {
		pr_debug("failed to PTRACE_PEEKUSER: %s\n",
			 strerror(errno));
		goto out;
	}

	pr_debug("rip %lx, bp_1 %p\n", rip, bp_1);

out:
	if (ptrace(PTRACE_DETACH, child, NULL, NULL)) {
		pr_debug("failed to PTRACE_DETACH: %s", strerror(errno));
		return TEST_FAIL;
	}

	return rip == (unsigned long) bp_1 ? TEST_OK : TEST_FAIL;
}

int test__bp_modify(struct test *test __maybe_unused,
		    int subtest __maybe_unused)
{
	TEST_ASSERT_VAL("modify test 1 failed\n", !bp_modify1());
	TEST_ASSERT_VAL("modify test 2 failed\n", !bp_modify2());

	return 0;
}