1// SPDX-License-Identifier: GPL-2.0
2#include <linux/compiler.h>
3#include <sys/types.h>
4#include <sys/wait.h>
5#include <sys/user.h>
6#include <syscall.h>
7#include <unistd.h>
8#include <stdio.h>
9#include <stdlib.h>
10#include <string.h>
11#include <sys/ptrace.h>
12#include <asm/ptrace.h>
13#include <errno.h>
14#include "debug.h"
15#include "tests/tests.h"
16#include "arch-tests.h"
17
18static noinline int bp_1(void)
19{
20	pr_debug("in %s\n", __func__);
21	return 0;
22}
23
24static noinline int bp_2(void)
25{
26	pr_debug("in %s\n", __func__);
27	return 0;
28}
29
30static int spawn_child(void)
31{
32	int child = fork();
33
34	if (child == 0) {
35		/*
36		 * The child sets itself for as tracee and
37		 * waits in signal for parent to trace it,
38		 * then it calls bp_1 and quits.
39		 */
40		int err = ptrace(PTRACE_TRACEME, 0, NULL, NULL);
41
42		if (err) {
43			pr_debug("failed to PTRACE_TRACEME\n");
44			exit(1);
45		}
46
47		raise(SIGCONT);
48		bp_1();
49		exit(0);
50	}
51
52	return child;
53}
54
55/*
56 * This tests creates HW breakpoint, tries to
57 * change it and checks it was properly changed.
58 */
59static int bp_modify1(void)
60{
61	pid_t child;
62	int status;
63	unsigned long rip = 0, dr7 = 1;
64
65	child = spawn_child();
66
67	waitpid(child, &status, 0);
68	if (WIFEXITED(status)) {
69		pr_debug("tracee exited prematurely 1\n");
70		return TEST_FAIL;
71	}
72
73	/*
74	 * The parent does following steps:
75	 *  - creates a new breakpoint (id 0) for bp_2 function
76	 *  - changes that breakpoint to bp_1 function
77	 *  - waits for the breakpoint to hit and checks
78	 *    it has proper rip of bp_1 function
79	 *  - detaches the child
80	 */
81	if (ptrace(PTRACE_POKEUSER, child,
82		   offsetof(struct user, u_debugreg[0]), bp_2)) {
83		pr_debug("failed to set breakpoint, 1st time: %s\n",
84			 strerror(errno));
85		goto out;
86	}
87
88	if (ptrace(PTRACE_POKEUSER, child,
89		   offsetof(struct user, u_debugreg[0]), bp_1)) {
90		pr_debug("failed to set breakpoint, 2nd time: %s\n",
91			 strerror(errno));
92		goto out;
93	}
94
95	if (ptrace(PTRACE_POKEUSER, child,
96		   offsetof(struct user, u_debugreg[7]), dr7)) {
97		pr_debug("failed to set dr7: %s\n", strerror(errno));
98		goto out;
99	}
100
101	if (ptrace(PTRACE_CONT, child, NULL, NULL)) {
102		pr_debug("failed to PTRACE_CONT: %s\n", strerror(errno));
103		goto out;
104	}
105
106	waitpid(child, &status, 0);
107	if (WIFEXITED(status)) {
108		pr_debug("tracee exited prematurely 2\n");
109		return TEST_FAIL;
110	}
111
112	rip = ptrace(PTRACE_PEEKUSER, child,
113		     offsetof(struct user_regs_struct, rip), NULL);
114	if (rip == (unsigned long) -1) {
115		pr_debug("failed to PTRACE_PEEKUSER: %s\n",
116			 strerror(errno));
117		goto out;
118	}
119
120	pr_debug("rip %lx, bp_1 %p\n", rip, bp_1);
121
122out:
123	if (ptrace(PTRACE_DETACH, child, NULL, NULL)) {
124		pr_debug("failed to PTRACE_DETACH: %s", strerror(errno));
125		return TEST_FAIL;
126	}
127
128	return rip == (unsigned long) bp_1 ? TEST_OK : TEST_FAIL;
129}
130
131/*
132 * This tests creates HW breakpoint, tries to
133 * change it to bogus value and checks the original
134 * breakpoint is hit.
135 */
136static int bp_modify2(void)
137{
138	pid_t child;
139	int status;
140	unsigned long rip = 0, dr7 = 1;
141
142	child = spawn_child();
143
144	waitpid(child, &status, 0);
145	if (WIFEXITED(status)) {
146		pr_debug("tracee exited prematurely 1\n");
147		return TEST_FAIL;
148	}
149
150	/*
151	 * The parent does following steps:
152	 *  - creates a new breakpoint (id 0) for bp_1 function
153	 *  - tries to change that breakpoint to (-1) address
154	 *  - waits for the breakpoint to hit and checks
155	 *    it has proper rip of bp_1 function
156	 *  - detaches the child
157	 */
158	if (ptrace(PTRACE_POKEUSER, child,
159		   offsetof(struct user, u_debugreg[0]), bp_1)) {
160		pr_debug("failed to set breakpoint: %s\n",
161			 strerror(errno));
162		goto out;
163	}
164
165	if (ptrace(PTRACE_POKEUSER, child,
166		   offsetof(struct user, u_debugreg[7]), dr7)) {
167		pr_debug("failed to set dr7: %s\n", strerror(errno));
168		goto out;
169	}
170
171	if (!ptrace(PTRACE_POKEUSER, child,
172		   offsetof(struct user, u_debugreg[0]), (unsigned long) (-1))) {
173		pr_debug("failed, breakpoint set to bogus address\n");
174		goto out;
175	}
176
177	if (ptrace(PTRACE_CONT, child, NULL, NULL)) {
178		pr_debug("failed to PTRACE_CONT: %s\n", strerror(errno));
179		goto out;
180	}
181
182	waitpid(child, &status, 0);
183	if (WIFEXITED(status)) {
184		pr_debug("tracee exited prematurely 2\n");
185		return TEST_FAIL;
186	}
187
188	rip = ptrace(PTRACE_PEEKUSER, child,
189		     offsetof(struct user_regs_struct, rip), NULL);
190	if (rip == (unsigned long) -1) {
191		pr_debug("failed to PTRACE_PEEKUSER: %s\n",
192			 strerror(errno));
193		goto out;
194	}
195
196	pr_debug("rip %lx, bp_1 %p\n", rip, bp_1);
197
198out:
199	if (ptrace(PTRACE_DETACH, child, NULL, NULL)) {
200		pr_debug("failed to PTRACE_DETACH: %s", strerror(errno));
201		return TEST_FAIL;
202	}
203
204	return rip == (unsigned long) bp_1 ? TEST_OK : TEST_FAIL;
205}
206
207int test__bp_modify(struct test_suite *test __maybe_unused,
208		    int subtest __maybe_unused)
209{
210	TEST_ASSERT_VAL("modify test 1 failed\n", !bp_modify1());
211	TEST_ASSERT_VAL("modify test 2 failed\n", !bp_modify2());
212
213	return 0;
214}
215