xref: /freebsd/sys/ddb/db_break.c (revision 1323ec57) 
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  Software.Distribution@CS.CMU.EDU
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
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
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
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
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
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
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
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
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 /*
208  * List breakpoints.
209  */
210 static void
211 db_list_breakpoints(void)
212 {
213 	register db_breakpoint_t	bkpt;
214 
215 	if (db_breakpoint_list == 0) {
216 	    db_printf("No breakpoints set\n");
217 	    return;
218 	}
219 
220 	db_printf(" Map      Count    Address\n");
221 	for (bkpt = db_breakpoint_list;
222 	     bkpt != 0;
223 	     bkpt = bkpt->link) {
224 	    db_printf("%s%8p %5d    ",
225 		      db_map_current(bkpt->map) ? "*" : " ",
226 		      (void *)bkpt->map, bkpt->init_count);
227 	    db_printsym(bkpt->address, DB_STGY_PROC);
228 	    db_printf("\n");
229 	}
230 }
231 
232 /* Delete breakpoint */
233 /*ARGSUSED*/
234 void
235 db_delete_cmd(db_expr_t addr, bool have_addr, db_expr_t count, char *modif)
236 {
237 	db_delete_breakpoint(db_map_addr(addr), (db_addr_t)addr);
238 }
239 
240 /* Set breakpoint with skip count */
241 /*ARGSUSED*/
242 void
243 db_breakpoint_cmd(db_expr_t addr, bool have_addr, db_expr_t count, char *modif)
244 {
245 	if (count == -1)
246 	    count = 1;
247 
248 	db_set_breakpoint(db_map_addr(addr), (db_addr_t)addr, count);
249 }
250 
251 /* list breakpoints */
252 void
253 db_listbreak_cmd(db_expr_t dummy1, bool dummy2, db_expr_t dummy3, char *dummy4)
254 {
255 	db_list_breakpoints();
256 }
257 
258 /*
259  *	We want ddb to be usable before most of the kernel has been
260  *	initialized.  In particular, current_thread() or kernel_map
261  *	(or both) may be null.
262  */
263 
264 bool
265 db_map_equal(vm_map_t map1, vm_map_t map2)
266 {
267 	return ((map1 == map2) ||
268 		((map1 == NULL) && (map2 == kernel_map)) ||
269 		((map1 == kernel_map) && (map2 == NULL)));
270 }
271 
272 bool
273 db_map_current(vm_map_t map)
274 {
275 #if 0
276 	thread_t	thread;
277 
278 	return ((map == NULL) ||
279 		(map == kernel_map) ||
280 		(((thread = current_thread()) != NULL) &&
281 		 (map == thread->task->map)));
282 #else
283 	return (true);
284 #endif
285 }
286 
287 vm_map_t
288 db_map_addr(vm_offset_t addr)
289 {
290 #if 0
291 	thread_t	thread;
292 
293 	/*
294 	 *	We want to return kernel_map for all
295 	 *	non-user addresses, even when debugging
296 	 *	kernel tasks with their own maps.
297 	 */
298 
299 	if ((VM_MIN_ADDRESS <= addr) &&
300 	    (addr < VM_MAX_ADDRESS) &&
301 	    ((thread = current_thread()) != NULL))
302 	    return thread->task->map;
303 	else
304 #endif
305 	    return kernel_map;
306 }
307