1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2016 Google, Inc.
4  *
5  * Original Code by Pavel Labath <labath@google.com>
6  *
7  * Code modified by Pratyush Anand <panand@redhat.com>
8  * for testing different byte select for each access size.
9  */
10 
11 #define _GNU_SOURCE
12 
13 #include <asm/ptrace.h>
14 #include <sys/types.h>
15 #include <sys/wait.h>
16 #include <sys/ptrace.h>
17 #include <sys/param.h>
18 #include <sys/uio.h>
19 #include <stdint.h>
20 #include <stdbool.h>
21 #include <stddef.h>
22 #include <string.h>
23 #include <stdio.h>
24 #include <unistd.h>
25 #include <elf.h>
26 #include <errno.h>
27 #include <signal.h>
28 
29 #include "../kselftest.h"
30 
31 static volatile uint8_t var[96] __attribute__((__aligned__(32)));
32 
33 static void child(int size, int wr)
34 {
35 	volatile uint8_t *addr = &var[32 + wr];
36 
37 	if (ptrace(PTRACE_TRACEME, 0, NULL, NULL) != 0) {
38 		ksft_print_msg(
39 			"ptrace(PTRACE_TRACEME) failed: %s\n",
40 			strerror(errno));
41 		_exit(1);
42 	}
43 
44 	if (raise(SIGSTOP) != 0) {
45 		ksft_print_msg(
46 			"raise(SIGSTOP) failed: %s\n", strerror(errno));
47 		_exit(1);
48 	}
49 
50 	if ((uintptr_t) addr % size) {
51 		ksft_print_msg(
52 			 "Wrong address write for the given size: %s\n",
53 			 strerror(errno));
54 		_exit(1);
55 	}
56 
57 	switch (size) {
58 	case 1:
59 		*addr = 47;
60 		break;
61 	case 2:
62 		*(uint16_t *)addr = 47;
63 		break;
64 	case 4:
65 		*(uint32_t *)addr = 47;
66 		break;
67 	case 8:
68 		*(uint64_t *)addr = 47;
69 		break;
70 	case 16:
71 		__asm__ volatile ("stp x29, x30, %0" : "=m" (addr[0]));
72 		break;
73 	case 32:
74 		__asm__ volatile ("stp q29, q30, %0" : "=m" (addr[0]));
75 		break;
76 	}
77 
78 	_exit(0);
79 }
80 
81 static bool set_watchpoint(pid_t pid, int size, int wp)
82 {
83 	const volatile uint8_t *addr = &var[32 + wp];
84 	const int offset = (uintptr_t)addr % 8;
85 	const unsigned int byte_mask = ((1 << size) - 1) << offset;
86 	const unsigned int type = 2; /* Write */
87 	const unsigned int enable = 1;
88 	const unsigned int control = byte_mask << 5 | type << 3 | enable;
89 	struct user_hwdebug_state dreg_state;
90 	struct iovec iov;
91 
92 	memset(&dreg_state, 0, sizeof(dreg_state));
93 	dreg_state.dbg_regs[0].addr = (uintptr_t)(addr - offset);
94 	dreg_state.dbg_regs[0].ctrl = control;
95 	iov.iov_base = &dreg_state;
96 	iov.iov_len = offsetof(struct user_hwdebug_state, dbg_regs) +
97 				sizeof(dreg_state.dbg_regs[0]);
98 	if (ptrace(PTRACE_SETREGSET, pid, NT_ARM_HW_WATCH, &iov) == 0)
99 		return true;
100 
101 	if (errno == EIO)
102 		ksft_print_msg(
103 			"ptrace(PTRACE_SETREGSET, NT_ARM_HW_WATCH) not supported on this hardware: %s\n",
104 			strerror(errno));
105 
106 	ksft_print_msg(
107 		"ptrace(PTRACE_SETREGSET, NT_ARM_HW_WATCH) failed: %s\n",
108 		strerror(errno));
109 	return false;
110 }
111 
112 static bool run_test(int wr_size, int wp_size, int wr, int wp)
113 {
114 	int status;
115 	siginfo_t siginfo;
116 	pid_t pid = fork();
117 	pid_t wpid;
118 
119 	if (pid < 0) {
120 		ksft_test_result_fail(
121 			"fork() failed: %s\n", strerror(errno));
122 		return false;
123 	}
124 	if (pid == 0)
125 		child(wr_size, wr);
126 
127 	wpid = waitpid(pid, &status, __WALL);
128 	if (wpid != pid) {
129 		ksft_print_msg(
130 			"waitpid() failed: %s\n", strerror(errno));
131 		return false;
132 	}
133 	if (!WIFSTOPPED(status)) {
134 		ksft_print_msg(
135 			"child did not stop: %s\n", strerror(errno));
136 		return false;
137 	}
138 	if (WSTOPSIG(status) != SIGSTOP) {
139 		ksft_print_msg("child did not stop with SIGSTOP\n");
140 		return false;
141 	}
142 
143 	if (!set_watchpoint(pid, wp_size, wp))
144 		return false;
145 
146 	if (ptrace(PTRACE_CONT, pid, NULL, NULL) < 0) {
147 		ksft_print_msg(
148 			"ptrace(PTRACE_CONT) failed: %s\n",
149 			strerror(errno));
150 		return false;
151 	}
152 
153 	alarm(3);
154 	wpid = waitpid(pid, &status, __WALL);
155 	if (wpid != pid) {
156 		ksft_print_msg(
157 			"waitpid() failed: %s\n", strerror(errno));
158 		return false;
159 	}
160 	alarm(0);
161 	if (WIFEXITED(status)) {
162 		ksft_print_msg("child exited prematurely\n");
163 		return false;
164 	}
165 	if (!WIFSTOPPED(status)) {
166 		ksft_print_msg("child did not stop\n");
167 		return false;
168 	}
169 	if (WSTOPSIG(status) != SIGTRAP) {
170 		ksft_print_msg("child did not stop with SIGTRAP\n");
171 		return false;
172 	}
173 	if (ptrace(PTRACE_GETSIGINFO, pid, NULL, &siginfo) != 0) {
174 		ksft_print_msg(
175 			"ptrace(PTRACE_GETSIGINFO): %s\n",
176 			strerror(errno));
177 		return false;
178 	}
179 	if (siginfo.si_code != TRAP_HWBKPT) {
180 		ksft_print_msg(
181 			"Unexpected si_code %d\n", siginfo.si_code);
182 		return false;
183 	}
184 
185 	kill(pid, SIGKILL);
186 	wpid = waitpid(pid, &status, 0);
187 	if (wpid != pid) {
188 		ksft_print_msg(
189 			"waitpid() failed: %s\n", strerror(errno));
190 		return false;
191 	}
192 	return true;
193 }
194 
195 static void sigalrm(int sig)
196 {
197 }
198 
199 int main(int argc, char **argv)
200 {
201 	int opt;
202 	bool succeeded = true;
203 	struct sigaction act;
204 	int wr, wp, size;
205 	bool result;
206 
207 	ksft_print_header();
208 	ksft_set_plan(213);
209 
210 	act.sa_handler = sigalrm;
211 	sigemptyset(&act.sa_mask);
212 	act.sa_flags = 0;
213 	sigaction(SIGALRM, &act, NULL);
214 	for (size = 1; size <= 32; size = size*2) {
215 		for (wr = 0; wr <= 32; wr = wr + size) {
216 			for (wp = wr - size; wp <= wr + size; wp = wp + size) {
217 				result = run_test(size, MIN(size, 8), wr, wp);
218 				if ((result && wr == wp) ||
219 				    (!result && wr != wp))
220 					ksft_test_result_pass(
221 						"Test size = %d write offset = %d watchpoint offset = %d\n",
222 						size, wr, wp);
223 				else {
224 					ksft_test_result_fail(
225 						"Test size = %d write offset = %d watchpoint offset = %d\n",
226 						size, wr, wp);
227 					succeeded = false;
228 				}
229 			}
230 		}
231 	}
232 
233 	for (size = 1; size <= 32; size = size*2) {
234 		if (run_test(size, 8, -size, -8))
235 			ksft_test_result_pass(
236 				"Test size = %d write offset = %d watchpoint offset = -8\n",
237 				size, -size);
238 		else {
239 			ksft_test_result_fail(
240 				"Test size = %d write offset = %d watchpoint offset = -8\n",
241 				size, -size);
242 			succeeded = false;
243 		}
244 	}
245 
246 	if (succeeded)
247 		ksft_exit_pass();
248 	else
249 		ksft_exit_fail();
250 }
251