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