1 /*-
2 * SPDX-License-Identifier: MIT-CMU
3 *
4 * Mach Operating System
5 * Copyright (c) 1991,1990 Carnegie Mellon University
6 * All Rights Reserved.
7 *
8 * Permission to use, copy, modify and distribute this software and its
9 * documentation is hereby granted, provided that both the copyright
10 * notice and this permission notice appear in all copies of the
11 * software, derivative works or modified versions, and any portions
12 * thereof, and that both notices appear in supporting documentation.
13 *
14 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
15 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
16 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
17 *
18 * Carnegie Mellon requests users of this software to return to
19 *
20 * Software Distribution Coordinator or [email protected]
21 * School of Computer Science
22 * Carnegie Mellon University
23 * Pittsburgh PA 15213-3890
24 *
25 * any improvements or extensions that they make and grant Carnegie the
26 * rights to redistribute these changes.
27 *
28 */
29 /*
30 * Author: David B. Golub, Carnegie Mellon University
31 * Date: 7/90
32 */
33 /*
34 * Breakpoints.
35 */
36
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39
40 #include <sys/param.h>
41
42 #include <vm/vm.h>
43 #include <vm/vm_kern.h>
44
45 #include <ddb/ddb.h>
46 #include <ddb/db_break.h>
47 #include <ddb/db_access.h>
48 #include <ddb/db_sym.h>
49
50 #define NBREAKPOINTS 100
51 static struct db_breakpoint db_break_table[NBREAKPOINTS];
52 static db_breakpoint_t db_next_free_breakpoint = &db_break_table[0];
53 static db_breakpoint_t db_free_breakpoints = 0;
54 static db_breakpoint_t db_breakpoint_list = 0;
55
56 static db_breakpoint_t db_breakpoint_alloc(void);
57 static void db_breakpoint_free(db_breakpoint_t bkpt);
58 static void db_delete_breakpoint(vm_map_t map, db_addr_t addr);
59 static db_breakpoint_t db_find_breakpoint(vm_map_t map, db_addr_t addr);
60 static void db_list_breakpoints(void);
61 static void db_set_breakpoint(vm_map_t map, db_addr_t addr, int count);
62
63 static db_breakpoint_t
db_breakpoint_alloc(void)64 db_breakpoint_alloc(void)
65 {
66 register db_breakpoint_t bkpt;
67
68 if ((bkpt = db_free_breakpoints) != 0) {
69 db_free_breakpoints = bkpt->link;
70 return (bkpt);
71 }
72 if (db_next_free_breakpoint == &db_break_table[NBREAKPOINTS]) {
73 db_printf("All breakpoints used.\n");
74 return (0);
75 }
76 bkpt = db_next_free_breakpoint;
77 db_next_free_breakpoint++;
78
79 return (bkpt);
80 }
81
82 static void
db_breakpoint_free(db_breakpoint_t bkpt)83 db_breakpoint_free(db_breakpoint_t bkpt)
84 {
85 bkpt->link = db_free_breakpoints;
86 db_free_breakpoints = bkpt;
87 }
88
89 static void
db_set_breakpoint(vm_map_t map,db_addr_t addr,int count)90 db_set_breakpoint(vm_map_t map, db_addr_t addr, int count)
91 {
92 register db_breakpoint_t bkpt;
93
94 if (db_find_breakpoint(map, addr)) {
95 db_printf("Already set.\n");
96 return;
97 }
98
99 bkpt = db_breakpoint_alloc();
100 if (bkpt == 0) {
101 db_printf("Too many breakpoints.\n");
102 return;
103 }
104
105 bkpt->map = map;
106 bkpt->address = addr;
107 bkpt->flags = 0;
108 bkpt->init_count = count;
109 bkpt->count = count;
110
111 bkpt->link = db_breakpoint_list;
112 db_breakpoint_list = bkpt;
113 }
114
115 static void
db_delete_breakpoint(vm_map_t map,db_addr_t addr)116 db_delete_breakpoint(vm_map_t map, db_addr_t addr)
117 {
118 register db_breakpoint_t bkpt;
119 register db_breakpoint_t *prev;
120
121 for (prev = &db_breakpoint_list;
122 (bkpt = *prev) != 0;
123 prev = &bkpt->link) {
124 if (db_map_equal(bkpt->map, map) &&
125 (bkpt->address == addr)) {
126 *prev = bkpt->link;
127 break;
128 }
129 }
130 if (bkpt == 0) {
131 db_printf("Not set.\n");
132 return;
133 }
134
135 db_breakpoint_free(bkpt);
136 }
137
138 static db_breakpoint_t
db_find_breakpoint(vm_map_t map,db_addr_t addr)139 db_find_breakpoint(vm_map_t map, db_addr_t addr)
140 {
141 register db_breakpoint_t bkpt;
142
143 for (bkpt = db_breakpoint_list;
144 bkpt != 0;
145 bkpt = bkpt->link)
146 {
147 if (db_map_equal(bkpt->map, map) &&
148 (bkpt->address == addr))
149 return (bkpt);
150 }
151 return (0);
152 }
153
154 db_breakpoint_t
db_find_breakpoint_here(db_addr_t addr)155 db_find_breakpoint_here(db_addr_t addr)
156 {
157 return db_find_breakpoint(db_map_addr(addr), addr);
158 }
159
160 static bool db_breakpoints_inserted = true;
161
162 #ifndef BKPT_WRITE
163 #define BKPT_WRITE(addr, storage) \
164 do { \
165 *storage = db_get_value(addr, BKPT_SIZE, false); \
166 db_put_value(addr, BKPT_SIZE, BKPT_SET(*storage)); \
167 } while (0)
168 #endif
169
170 #ifndef BKPT_CLEAR
171 #define BKPT_CLEAR(addr, storage) \
172 db_put_value(addr, BKPT_SIZE, *storage)
173 #endif
174
175 void
db_set_breakpoints(void)176 db_set_breakpoints(void)
177 {
178 register db_breakpoint_t bkpt;
179
180 if (!db_breakpoints_inserted) {
181 for (bkpt = db_breakpoint_list;
182 bkpt != 0;
183 bkpt = bkpt->link)
184 if (db_map_current(bkpt->map)) {
185 BKPT_WRITE(bkpt->address, &bkpt->bkpt_inst);
186 }
187 db_breakpoints_inserted = true;
188 }
189 }
190
191 void
db_clear_breakpoints(void)192 db_clear_breakpoints(void)
193 {
194 register db_breakpoint_t bkpt;
195
196 if (db_breakpoints_inserted) {
197 for (bkpt = db_breakpoint_list;
198 bkpt != 0;
199 bkpt = bkpt->link)
200 if (db_map_current(bkpt->map)) {
201 BKPT_CLEAR(bkpt->address, &bkpt->bkpt_inst);
202 }
203 db_breakpoints_inserted = false;
204 }
205 }
206
207 #ifdef SOFTWARE_SSTEP
208 /*
209 * Set a temporary breakpoint.
210 * The instruction is changed immediately,
211 * so the breakpoint does not have to be on the breakpoint list.
212 */
213 db_breakpoint_t
db_set_temp_breakpoint(db_addr_t addr)214 db_set_temp_breakpoint(db_addr_t addr)
215 {
216 register db_breakpoint_t bkpt;
217
218 bkpt = db_breakpoint_alloc();
219 if (bkpt == 0) {
220 db_printf("Too many breakpoints.\n");
221 return 0;
222 }
223
224 bkpt->map = NULL;
225 bkpt->address = addr;
226 bkpt->flags = BKPT_TEMP;
227 bkpt->init_count = 1;
228 bkpt->count = 1;
229
230 BKPT_WRITE(bkpt->address, &bkpt->bkpt_inst);
231 return bkpt;
232 }
233
234 void
db_delete_temp_breakpoint(db_breakpoint_t bkpt)235 db_delete_temp_breakpoint(db_breakpoint_t bkpt)
236 {
237 BKPT_CLEAR(bkpt->address, &bkpt->bkpt_inst);
238 db_breakpoint_free(bkpt);
239 }
240 #endif /* SOFTWARE_SSTEP */
241
242 /*
243 * List breakpoints.
244 */
245 static void
db_list_breakpoints(void)246 db_list_breakpoints(void)
247 {
248 register db_breakpoint_t bkpt;
249
250 if (db_breakpoint_list == 0) {
251 db_printf("No breakpoints set\n");
252 return;
253 }
254
255 db_printf(" Map Count Address\n");
256 for (bkpt = db_breakpoint_list;
257 bkpt != 0;
258 bkpt = bkpt->link) {
259 db_printf("%s%8p %5d ",
260 db_map_current(bkpt->map) ? "*" : " ",
261 (void *)bkpt->map, bkpt->init_count);
262 db_printsym(bkpt->address, DB_STGY_PROC);
263 db_printf("\n");
264 }
265 }
266
267 /* Delete breakpoint */
268 /*ARGSUSED*/
269 void
db_delete_cmd(db_expr_t addr,bool have_addr,db_expr_t count,char * modif)270 db_delete_cmd(db_expr_t addr, bool have_addr, db_expr_t count, char *modif)
271 {
272 db_delete_breakpoint(db_map_addr(addr), (db_addr_t)addr);
273 }
274
275 /* Set breakpoint with skip count */
276 /*ARGSUSED*/
277 void
db_breakpoint_cmd(db_expr_t addr,bool have_addr,db_expr_t count,char * modif)278 db_breakpoint_cmd(db_expr_t addr, bool have_addr, db_expr_t count, char *modif)
279 {
280 if (count == -1)
281 count = 1;
282
283 db_set_breakpoint(db_map_addr(addr), (db_addr_t)addr, count);
284 }
285
286 /* list breakpoints */
287 void
db_listbreak_cmd(db_expr_t dummy1,bool dummy2,db_expr_t dummy3,char * dummy4)288 db_listbreak_cmd(db_expr_t dummy1, bool dummy2, db_expr_t dummy3, char *dummy4)
289 {
290 db_list_breakpoints();
291 }
292
293 /*
294 * We want ddb to be usable before most of the kernel has been
295 * initialized. In particular, current_thread() or kernel_map
296 * (or both) may be null.
297 */
298
299 bool
db_map_equal(vm_map_t map1,vm_map_t map2)300 db_map_equal(vm_map_t map1, vm_map_t map2)
301 {
302 return ((map1 == map2) ||
303 ((map1 == NULL) && (map2 == kernel_map)) ||
304 ((map1 == kernel_map) && (map2 == NULL)));
305 }
306
307 bool
db_map_current(vm_map_t map)308 db_map_current(vm_map_t map)
309 {
310 #if 0
311 thread_t thread;
312
313 return ((map == NULL) ||
314 (map == kernel_map) ||
315 (((thread = current_thread()) != NULL) &&
316 (map == thread->task->map)));
317 #else
318 return (true);
319 #endif
320 }
321
322 vm_map_t
db_map_addr(vm_offset_t addr)323 db_map_addr(vm_offset_t addr)
324 {
325 #if 0
326 thread_t thread;
327
328 /*
329 * We want to return kernel_map for all
330 * non-user addresses, even when debugging
331 * kernel tasks with their own maps.
332 */
333
334 if ((VM_MIN_ADDRESS <= addr) &&
335 (addr < VM_MAX_ADDRESS) &&
336 ((thread = current_thread()) != NULL))
337 return thread->task->map;
338 else
339 #endif
340 return kernel_map;
341 }
342