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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/*
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}