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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2011 Red Hat, Inc., Frederic Weisbecker <fweisbec@redhat.com>
4 *
5 * Selftests for breakpoints (and more generally the do_debug() path) in x86.
6 */
7
8
9#include <sys/ptrace.h>
10#include <unistd.h>
11#include <stddef.h>
12#include <sys/user.h>
13#include <stdio.h>
14#include <stdlib.h>
15#include <signal.h>
16#include <sys/types.h>
17#include <sys/wait.h>
18#include <errno.h>
19#include <string.h>
20
21#include "../kselftest.h"
22
23#define COUNT_ISN_BPS 4
24#define COUNT_WPS 4
25
26/* Breakpoint access modes */
27enum {
28 BP_X = 1,
29 BP_RW = 2,
30 BP_W = 4,
31};
32
33static pid_t child_pid;
34
35/*
36 * Ensures the child and parent are always "talking" about
37 * the same test sequence. (ie: that we haven't forgotten
38 * to call check_trapped() somewhere).
39 */
40static int nr_tests;
41
42static void set_breakpoint_addr(void *addr, int n)
43{
44 int ret;
45
46 ret = ptrace(PTRACE_POKEUSER, child_pid,
47 offsetof(struct user, u_debugreg[n]), addr);
48 if (ret)
49 ksft_exit_fail_msg("Can't set breakpoint addr: %s\n",
50 strerror(errno));
51}
52
53static void toggle_breakpoint(int n, int type, int len,
54 int local, int global, int set)
55{
56 int ret;
57
58 int xtype, xlen;
59 unsigned long vdr7, dr7;
60
61 switch (type) {
62 case BP_X:
63 xtype = 0;
64 break;
65 case BP_W:
66 xtype = 1;
67 break;
68 case BP_RW:
69 xtype = 3;
70 break;
71 }
72
73 switch (len) {
74 case 1:
75 xlen = 0;
76 break;
77 case 2:
78 xlen = 4;
79 break;
80 case 4:
81 xlen = 0xc;
82 break;
83 case 8:
84 xlen = 8;
85 break;
86 }
87
88 dr7 = ptrace(PTRACE_PEEKUSER, child_pid,
89 offsetof(struct user, u_debugreg[7]), 0);
90
91 vdr7 = (xlen | xtype) << 16;
92 vdr7 <<= 4 * n;
93
94 if (local) {
95 vdr7 |= 1 << (2 * n);
96 vdr7 |= 1 << 8;
97 }
98 if (global) {
99 vdr7 |= 2 << (2 * n);
100 vdr7 |= 1 << 9;
101 }
102
103 if (set)
104 dr7 |= vdr7;
105 else
106 dr7 &= ~vdr7;
107
108 ret = ptrace(PTRACE_POKEUSER, child_pid,
109 offsetof(struct user, u_debugreg[7]), dr7);
110 if (ret) {
111 ksft_print_msg("Can't set dr7: %s\n", strerror(errno));
112 exit(-1);
113 }
114}
115
116/* Dummy variables to test read/write accesses */
117static unsigned long long dummy_var[4];
118
119/* Dummy functions to test execution accesses */
120static void dummy_func(void) { }
121static void dummy_func1(void) { }
122static void dummy_func2(void) { }
123static void dummy_func3(void) { }
124
125static void (*dummy_funcs[])(void) = {
126 dummy_func,
127 dummy_func1,
128 dummy_func2,
129 dummy_func3,
130};
131
132static int trapped;
133
134static void check_trapped(void)
135{
136 /*
137 * If we haven't trapped, wake up the parent
138 * so that it notices the failure.
139 */
140 if (!trapped)
141 kill(getpid(), SIGUSR1);
142 trapped = 0;
143
144 nr_tests++;
145}
146
147static void write_var(int len)
148{
149 char *pcval; short *psval; int *pival; long long *plval;
150 int i;
151
152 for (i = 0; i < 4; i++) {
153 switch (len) {
154 case 1:
155 pcval = (char *)&dummy_var[i];
156 *pcval = 0xff;
157 break;
158 case 2:
159 psval = (short *)&dummy_var[i];
160 *psval = 0xffff;
161 break;
162 case 4:
163 pival = (int *)&dummy_var[i];
164 *pival = 0xffffffff;
165 break;
166 case 8:
167 plval = (long long *)&dummy_var[i];
168 *plval = 0xffffffffffffffffLL;
169 break;
170 }
171 check_trapped();
172 }
173}
174
175static void read_var(int len)
176{
177 char cval; short sval; int ival; long long lval;
178 int i;
179
180 for (i = 0; i < 4; i++) {
181 switch (len) {
182 case 1:
183 cval = *(char *)&dummy_var[i];
184 break;
185 case 2:
186 sval = *(short *)&dummy_var[i];
187 break;
188 case 4:
189 ival = *(int *)&dummy_var[i];
190 break;
191 case 8:
192 lval = *(long long *)&dummy_var[i];
193 break;
194 }
195 check_trapped();
196 }
197}
198
199/*
200 * Do the r/w/x accesses to trigger the breakpoints. And run
201 * the usual traps.
202 */
203static void trigger_tests(void)
204{
205 int len, local, global, i;
206 char val;
207 int ret;
208
209 ret = ptrace(PTRACE_TRACEME, 0, NULL, 0);
210 if (ret) {
211 ksft_print_msg("Can't be traced? %s\n", strerror(errno));
212 return;
213 }
214
215 /* Wake up father so that it sets up the first test */
216 kill(getpid(), SIGUSR1);
217
218 /* Test instruction breakpoints */
219 for (local = 0; local < 2; local++) {
220 for (global = 0; global < 2; global++) {
221 if (!local && !global)
222 continue;
223
224 for (i = 0; i < COUNT_ISN_BPS; i++) {
225 dummy_funcs[i]();
226 check_trapped();
227 }
228 }
229 }
230
231 /* Test write watchpoints */
232 for (len = 1; len <= sizeof(long); len <<= 1) {
233 for (local = 0; local < 2; local++) {
234 for (global = 0; global < 2; global++) {
235 if (!local && !global)
236 continue;
237 write_var(len);
238 }
239 }
240 }
241
242 /* Test read/write watchpoints (on read accesses) */
243 for (len = 1; len <= sizeof(long); len <<= 1) {
244 for (local = 0; local < 2; local++) {
245 for (global = 0; global < 2; global++) {
246 if (!local && !global)
247 continue;
248 read_var(len);
249 }
250 }
251 }
252
253 /* Icebp trap */
254 asm(".byte 0xf1\n");
255 check_trapped();
256
257 /* Int 3 trap */
258 asm("int $3\n");
259 check_trapped();
260
261 kill(getpid(), SIGUSR1);
262}
263
264static void check_success(const char *msg)
265{
266 int child_nr_tests;
267 int status;
268 int ret;
269
270 /* Wait for the child to SIGTRAP */
271 wait(&status);
272
273 ret = 0;
274
275 if (WSTOPSIG(status) == SIGTRAP) {
276 child_nr_tests = ptrace(PTRACE_PEEKDATA, child_pid,
277 &nr_tests, 0);
278 if (child_nr_tests == nr_tests)
279 ret = 1;
280 if (ptrace(PTRACE_POKEDATA, child_pid, &trapped, 1))
281 ksft_exit_fail_msg("Can't poke: %s\n", strerror(errno));
282 }
283
284 nr_tests++;
285
286 if (ret)
287 ksft_test_result_pass("%s", msg);
288 else
289 ksft_test_result_fail("%s", msg);
290}
291
292static void launch_instruction_breakpoints(char *buf, int local, int global)
293{
294 int i;
295
296 for (i = 0; i < COUNT_ISN_BPS; i++) {
297 set_breakpoint_addr(dummy_funcs[i], i);
298 toggle_breakpoint(i, BP_X, 1, local, global, 1);
299 ptrace(PTRACE_CONT, child_pid, NULL, 0);
300 sprintf(buf, "Test breakpoint %d with local: %d global: %d\n",
301 i, local, global);
302 check_success(buf);
303 toggle_breakpoint(i, BP_X, 1, local, global, 0);
304 }
305}
306
307static void launch_watchpoints(char *buf, int mode, int len,
308 int local, int global)
309{
310 const char *mode_str;
311 int i;
312
313 if (mode == BP_W)
314 mode_str = "write";
315 else
316 mode_str = "read";
317
318 for (i = 0; i < COUNT_WPS; i++) {
319 set_breakpoint_addr(&dummy_var[i], i);
320 toggle_breakpoint(i, mode, len, local, global, 1);
321 ptrace(PTRACE_CONT, child_pid, NULL, 0);
322 sprintf(buf,
323 "Test %s watchpoint %d with len: %d local: %d global: %d\n",
324 mode_str, i, len, local, global);
325 check_success(buf);
326 toggle_breakpoint(i, mode, len, local, global, 0);
327 }
328}
329
330/* Set the breakpoints and check the child successfully trigger them */
331static void launch_tests(void)
332{
333 char buf[1024];
334 unsigned int tests = 0;
335 int len, local, global, i;
336
337 tests += 3 * COUNT_ISN_BPS;
338 tests += sizeof(long) / 2 * 3 * COUNT_WPS;
339 tests += sizeof(long) / 2 * 3 * COUNT_WPS;
340 tests += 2;
341 ksft_set_plan(tests);
342
343 /* Instruction breakpoints */
344 for (local = 0; local < 2; local++) {
345 for (global = 0; global < 2; global++) {
346 if (!local && !global)
347 continue;
348 launch_instruction_breakpoints(buf, local, global);
349 }
350 }
351
352 /* Write watchpoint */
353 for (len = 1; len <= sizeof(long); len <<= 1) {
354 for (local = 0; local < 2; local++) {
355 for (global = 0; global < 2; global++) {
356 if (!local && !global)
357 continue;
358 launch_watchpoints(buf, BP_W, len,
359 local, global);
360 }
361 }
362 }
363
364 /* Read-Write watchpoint */
365 for (len = 1; len <= sizeof(long); len <<= 1) {
366 for (local = 0; local < 2; local++) {
367 for (global = 0; global < 2; global++) {
368 if (!local && !global)
369 continue;
370 launch_watchpoints(buf, BP_RW, len,
371 local, global);
372 }
373 }
374 }
375
376 /* Icebp traps */
377 ptrace(PTRACE_CONT, child_pid, NULL, 0);
378 check_success("Test icebp\n");
379
380 /* Int 3 traps */
381 ptrace(PTRACE_CONT, child_pid, NULL, 0);
382 check_success("Test int 3 trap\n");
383
384 ptrace(PTRACE_CONT, child_pid, NULL, 0);
385}
386
387int main(int argc, char **argv)
388{
389 pid_t pid;
390 int ret;
391
392 ksft_print_header();
393
394 pid = fork();
395 if (!pid) {
396 trigger_tests();
397 exit(0);
398 }
399
400 child_pid = pid;
401
402 wait(NULL);
403
404 launch_tests();
405
406 wait(NULL);
407
408 ksft_exit_pass();
409}
1/*
2 * Copyright (C) 2011 Red Hat, Inc., Frederic Weisbecker <fweisbec@redhat.com>
3 *
4 * Licensed under the terms of the GNU GPL License version 2
5 *
6 * Selftests for breakpoints (and more generally the do_debug() path) in x86.
7 */
8
9
10#include <sys/ptrace.h>
11#include <unistd.h>
12#include <stddef.h>
13#include <sys/user.h>
14#include <stdio.h>
15#include <stdlib.h>
16#include <signal.h>
17#include <sys/types.h>
18#include <sys/wait.h>
19
20
21/* Breakpoint access modes */
22enum {
23 BP_X = 1,
24 BP_RW = 2,
25 BP_W = 4,
26};
27
28static pid_t child_pid;
29
30/*
31 * Ensures the child and parent are always "talking" about
32 * the same test sequence. (ie: that we haven't forgotten
33 * to call check_trapped() somewhere).
34 */
35static int nr_tests;
36
37static void set_breakpoint_addr(void *addr, int n)
38{
39 int ret;
40
41 ret = ptrace(PTRACE_POKEUSER, child_pid,
42 offsetof(struct user, u_debugreg[n]), addr);
43 if (ret) {
44 perror("Can't set breakpoint addr\n");
45 exit(-1);
46 }
47}
48
49static void toggle_breakpoint(int n, int type, int len,
50 int local, int global, int set)
51{
52 int ret;
53
54 int xtype, xlen;
55 unsigned long vdr7, dr7;
56
57 switch (type) {
58 case BP_X:
59 xtype = 0;
60 break;
61 case BP_W:
62 xtype = 1;
63 break;
64 case BP_RW:
65 xtype = 3;
66 break;
67 }
68
69 switch (len) {
70 case 1:
71 xlen = 0;
72 break;
73 case 2:
74 xlen = 4;
75 break;
76 case 4:
77 xlen = 0xc;
78 break;
79 case 8:
80 xlen = 8;
81 break;
82 }
83
84 dr7 = ptrace(PTRACE_PEEKUSER, child_pid,
85 offsetof(struct user, u_debugreg[7]), 0);
86
87 vdr7 = (xlen | xtype) << 16;
88 vdr7 <<= 4 * n;
89
90 if (local) {
91 vdr7 |= 1 << (2 * n);
92 vdr7 |= 1 << 8;
93 }
94 if (global) {
95 vdr7 |= 2 << (2 * n);
96 vdr7 |= 1 << 9;
97 }
98
99 if (set)
100 dr7 |= vdr7;
101 else
102 dr7 &= ~vdr7;
103
104 ret = ptrace(PTRACE_POKEUSER, child_pid,
105 offsetof(struct user, u_debugreg[7]), dr7);
106 if (ret) {
107 perror("Can't set dr7");
108 exit(-1);
109 }
110}
111
112/* Dummy variables to test read/write accesses */
113static unsigned long long dummy_var[4];
114
115/* Dummy functions to test execution accesses */
116static void dummy_func(void) { }
117static void dummy_func1(void) { }
118static void dummy_func2(void) { }
119static void dummy_func3(void) { }
120
121static void (*dummy_funcs[])(void) = {
122 dummy_func,
123 dummy_func1,
124 dummy_func2,
125 dummy_func3,
126};
127
128static int trapped;
129
130static void check_trapped(void)
131{
132 /*
133 * If we haven't trapped, wake up the parent
134 * so that it notices the failure.
135 */
136 if (!trapped)
137 kill(getpid(), SIGUSR1);
138 trapped = 0;
139
140 nr_tests++;
141}
142
143static void write_var(int len)
144{
145 char *pcval; short *psval; int *pival; long long *plval;
146 int i;
147
148 for (i = 0; i < 4; i++) {
149 switch (len) {
150 case 1:
151 pcval = (char *)&dummy_var[i];
152 *pcval = 0xff;
153 break;
154 case 2:
155 psval = (short *)&dummy_var[i];
156 *psval = 0xffff;
157 break;
158 case 4:
159 pival = (int *)&dummy_var[i];
160 *pival = 0xffffffff;
161 break;
162 case 8:
163 plval = (long long *)&dummy_var[i];
164 *plval = 0xffffffffffffffffLL;
165 break;
166 }
167 check_trapped();
168 }
169}
170
171static void read_var(int len)
172{
173 char cval; short sval; int ival; long long lval;
174 int i;
175
176 for (i = 0; i < 4; i++) {
177 switch (len) {
178 case 1:
179 cval = *(char *)&dummy_var[i];
180 break;
181 case 2:
182 sval = *(short *)&dummy_var[i];
183 break;
184 case 4:
185 ival = *(int *)&dummy_var[i];
186 break;
187 case 8:
188 lval = *(long long *)&dummy_var[i];
189 break;
190 }
191 check_trapped();
192 }
193}
194
195/*
196 * Do the r/w/x accesses to trigger the breakpoints. And run
197 * the usual traps.
198 */
199static void trigger_tests(void)
200{
201 int len, local, global, i;
202 char val;
203 int ret;
204
205 ret = ptrace(PTRACE_TRACEME, 0, NULL, 0);
206 if (ret) {
207 perror("Can't be traced?\n");
208 return;
209 }
210
211 /* Wake up father so that it sets up the first test */
212 kill(getpid(), SIGUSR1);
213
214 /* Test instruction breakpoints */
215 for (local = 0; local < 2; local++) {
216 for (global = 0; global < 2; global++) {
217 if (!local && !global)
218 continue;
219
220 for (i = 0; i < 4; i++) {
221 dummy_funcs[i]();
222 check_trapped();
223 }
224 }
225 }
226
227 /* Test write watchpoints */
228 for (len = 1; len <= sizeof(long); len <<= 1) {
229 for (local = 0; local < 2; local++) {
230 for (global = 0; global < 2; global++) {
231 if (!local && !global)
232 continue;
233 write_var(len);
234 }
235 }
236 }
237
238 /* Test read/write watchpoints (on read accesses) */
239 for (len = 1; len <= sizeof(long); len <<= 1) {
240 for (local = 0; local < 2; local++) {
241 for (global = 0; global < 2; global++) {
242 if (!local && !global)
243 continue;
244 read_var(len);
245 }
246 }
247 }
248
249 /* Icebp trap */
250 asm(".byte 0xf1\n");
251 check_trapped();
252
253 /* Int 3 trap */
254 asm("int $3\n");
255 check_trapped();
256
257 kill(getpid(), SIGUSR1);
258}
259
260static void check_success(const char *msg)
261{
262 const char *msg2;
263 int child_nr_tests;
264 int status;
265
266 /* Wait for the child to SIGTRAP */
267 wait(&status);
268
269 msg2 = "Failed";
270
271 if (WSTOPSIG(status) == SIGTRAP) {
272 child_nr_tests = ptrace(PTRACE_PEEKDATA, child_pid,
273 &nr_tests, 0);
274 if (child_nr_tests == nr_tests)
275 msg2 = "Ok";
276 if (ptrace(PTRACE_POKEDATA, child_pid, &trapped, 1)) {
277 perror("Can't poke\n");
278 exit(-1);
279 }
280 }
281
282 nr_tests++;
283
284 printf("%s [%s]\n", msg, msg2);
285}
286
287static void launch_instruction_breakpoints(char *buf, int local, int global)
288{
289 int i;
290
291 for (i = 0; i < 4; i++) {
292 set_breakpoint_addr(dummy_funcs[i], i);
293 toggle_breakpoint(i, BP_X, 1, local, global, 1);
294 ptrace(PTRACE_CONT, child_pid, NULL, 0);
295 sprintf(buf, "Test breakpoint %d with local: %d global: %d",
296 i, local, global);
297 check_success(buf);
298 toggle_breakpoint(i, BP_X, 1, local, global, 0);
299 }
300}
301
302static void launch_watchpoints(char *buf, int mode, int len,
303 int local, int global)
304{
305 const char *mode_str;
306 int i;
307
308 if (mode == BP_W)
309 mode_str = "write";
310 else
311 mode_str = "read";
312
313 for (i = 0; i < 4; i++) {
314 set_breakpoint_addr(&dummy_var[i], i);
315 toggle_breakpoint(i, mode, len, local, global, 1);
316 ptrace(PTRACE_CONT, child_pid, NULL, 0);
317 sprintf(buf, "Test %s watchpoint %d with len: %d local: "
318 "%d global: %d", mode_str, i, len, local, global);
319 check_success(buf);
320 toggle_breakpoint(i, mode, len, local, global, 0);
321 }
322}
323
324/* Set the breakpoints and check the child successfully trigger them */
325static void launch_tests(void)
326{
327 char buf[1024];
328 int len, local, global, i;
329
330 /* Instruction breakpoints */
331 for (local = 0; local < 2; local++) {
332 for (global = 0; global < 2; global++) {
333 if (!local && !global)
334 continue;
335 launch_instruction_breakpoints(buf, local, global);
336 }
337 }
338
339 /* Write watchpoint */
340 for (len = 1; len <= sizeof(long); len <<= 1) {
341 for (local = 0; local < 2; local++) {
342 for (global = 0; global < 2; global++) {
343 if (!local && !global)
344 continue;
345 launch_watchpoints(buf, BP_W, len,
346 local, global);
347 }
348 }
349 }
350
351 /* Read-Write watchpoint */
352 for (len = 1; len <= sizeof(long); len <<= 1) {
353 for (local = 0; local < 2; local++) {
354 for (global = 0; global < 2; global++) {
355 if (!local && !global)
356 continue;
357 launch_watchpoints(buf, BP_RW, len,
358 local, global);
359 }
360 }
361 }
362
363 /* Icebp traps */
364 ptrace(PTRACE_CONT, child_pid, NULL, 0);
365 check_success("Test icebp");
366
367 /* Int 3 traps */
368 ptrace(PTRACE_CONT, child_pid, NULL, 0);
369 check_success("Test int 3 trap");
370
371 ptrace(PTRACE_CONT, child_pid, NULL, 0);
372}
373
374int main(int argc, char **argv)
375{
376 pid_t pid;
377 int ret;
378
379 pid = fork();
380 if (!pid) {
381 trigger_tests();
382 return 0;
383 }
384
385 child_pid = pid;
386
387 wait(NULL);
388
389 launch_tests();
390
391 wait(NULL);
392
393 return 0;
394}