1 /*        $NetBSD: db_watch.c,v 1.27 2007/02/22 06:41:01 thorpej Exp $          */
2 
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 "AS IS"
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  *        Author: Richard P. Draves, Carnegie Mellon University
29  *        Date:     10/90
30  */
31 
32 #include <sys/cdefs.h>
33 __KERNEL_RCSID(0, "$NetBSD: db_watch.c,v 1.27 2007/02/22 06:41:01 thorpej Exp $");
34 
35 #include <sys/param.h>
36 #include <sys/proc.h>
37 
38 #include <machine/db_machdep.h>
39 
40 #include <ddb/db_break.h>
41 #include <ddb/db_watch.h>
42 #include <ddb/db_lex.h>
43 #include <ddb/db_access.h>
44 #include <ddb/db_run.h>
45 #include <ddb/db_sym.h>
46 #include <ddb/db_output.h>
47 #include <ddb/db_command.h>
48 #include <ddb/db_extern.h>
49 
50 /*
51  * Watchpoints.
52  */
53 
54 static bool                             db_watchpoints_inserted = true;
55 
56 #define   NWATCHPOINTS        100
57 static struct db_watchpoint   db_watch_table[NWATCHPOINTS];
58 static db_watchpoint_t                  db_next_free_watchpoint = &db_watch_table[0];
59 static db_watchpoint_t                  db_free_watchpoints = 0;
60 static db_watchpoint_t                  db_watchpoint_list = 0;
61 
62 static void                   db_delete_watchpoint(struct vm_map *, db_addr_t);
63 static void                   db_list_watchpoints(void);
64 static void                   db_set_watchpoint(struct vm_map *, db_addr_t, vsize_t);
65 static db_watchpoint_t        db_watchpoint_alloc(void);
66 static void                   db_watchpoint_free(db_watchpoint_t);
67 
68 db_watchpoint_t
db_watchpoint_alloc(void)69 db_watchpoint_alloc(void)
70 {
71           db_watchpoint_t     watch;
72 
73           if ((watch = db_free_watchpoints) != 0) {
74                     db_free_watchpoints = watch->link;
75                     return (watch);
76           }
77           if (db_next_free_watchpoint == &db_watch_table[NWATCHPOINTS]) {
78                     db_printf("All watchpoints used.\n");
79                     return (0);
80           }
81           watch = db_next_free_watchpoint;
82           db_next_free_watchpoint++;
83 
84           return (watch);
85 }
86 
87 void
db_watchpoint_free(db_watchpoint_t watch)88 db_watchpoint_free(db_watchpoint_t watch)
89 {
90           watch->link = db_free_watchpoints;
91           db_free_watchpoints = watch;
92 }
93 
94 void
db_set_watchpoint(struct vm_map * map,db_addr_t addr,vsize_t size)95 db_set_watchpoint(struct vm_map *map, db_addr_t addr, vsize_t size)
96 {
97           db_watchpoint_t     watch;
98 
99           if (map == NULL) {
100                     db_printf("No map.\n");
101                     return;
102           }
103 
104           /*
105            *        Should we do anything fancy with overlapping regions?
106            */
107 
108           for (watch = db_watchpoint_list; watch != 0; watch = watch->link)
109                     if (db_map_equal(watch->map, map) &&
110                         (watch->loaddr == addr) &&
111                         (watch->hiaddr == addr+size)) {
112                               db_printf("Already set.\n");
113                               return;
114                     }
115 
116           watch = db_watchpoint_alloc();
117           if (watch == 0) {
118                     db_printf("Too many watchpoints.\n");
119                     return;
120           }
121 
122           watch->map = map;
123           watch->loaddr = addr;
124           watch->hiaddr = addr+size;
125 
126           watch->link = db_watchpoint_list;
127           db_watchpoint_list = watch;
128 
129           db_watchpoints_inserted = false;
130 }
131 
132 static void
db_delete_watchpoint(struct vm_map * map,db_addr_t addr)133 db_delete_watchpoint(struct vm_map *map, db_addr_t addr)
134 {
135           db_watchpoint_t     watch;
136           db_watchpoint_t     *prev;
137 
138           for (prev = &db_watchpoint_list;
139                (watch = *prev) != 0;
140                prev = &watch->link)
141                     if (db_map_equal(watch->map, map) &&
142                         (watch->loaddr <= addr) &&
143                         (addr < watch->hiaddr)) {
144                               *prev = watch->link;
145                               db_watchpoint_free(watch);
146                               return;
147                     }
148 
149           db_printf("Not set.\n");
150 }
151 
152 void
db_list_watchpoints(void)153 db_list_watchpoints(void)
154 {
155           db_watchpoint_t     watch;
156 
157           if (db_watchpoint_list == 0) {
158                     db_printf("No watchpoints set\n");
159                     return;
160           }
161 
162           db_printf(" Map        Address  Size\n");
163           for (watch = db_watchpoint_list; watch != 0; watch = watch->link)
164                     db_printf("%s%p  %8lx  %lx\n",
165                         db_map_current(watch->map) ? "*" : " ",
166                         watch->map, (long)watch->loaddr,
167                         (long)(watch->hiaddr - watch->loaddr));
168 }
169 
170 /* Delete watchpoint */
171 /*ARGSUSED*/
172 void
db_deletewatch_cmd(db_expr_t addr,bool have_addr,db_expr_t count,const char * modif)173 db_deletewatch_cmd(db_expr_t addr, bool have_addr,
174     db_expr_t count, const char *modif)
175 {
176 
177           db_delete_watchpoint(db_map_addr(addr), addr);
178 }
179 
180 /* Set watchpoint */
181 /*ARGSUSED*/
182 void
db_watchpoint_cmd(db_expr_t addr,bool have_addr,db_expr_t count,const char * modif)183 db_watchpoint_cmd(db_expr_t addr, bool have_addr,
184     db_expr_t count, const char *modif)
185 {
186           vsize_t size;
187           db_expr_t value;
188 
189           if (db_expression(&value))
190                     size = (vsize_t) value;
191           else
192                     size = 4;
193           db_skip_to_eol();
194 
195           db_set_watchpoint(db_map_addr(addr), addr, size);
196 }
197 
198 /* list watchpoints */
199 /*ARGSUSED*/
200 void
db_listwatch_cmd(db_expr_t addr,bool have_addr,db_expr_t count,const char * modif)201 db_listwatch_cmd(db_expr_t addr, bool have_addr,
202     db_expr_t count, const char *modif)
203 {
204 
205           db_list_watchpoints();
206 }
207 
208 void
db_set_watchpoints(void)209 db_set_watchpoints(void)
210 {
211           db_watchpoint_t     watch;
212 
213           if (!db_watchpoints_inserted) {
214                     for (watch = db_watchpoint_list;
215                          watch != 0;
216                          watch = watch->link) {
217                               pmap_protect(watch->map->pmap,
218                                   trunc_page(watch->loaddr),
219                                   round_page(watch->hiaddr),
220                                   VM_PROT_READ);
221                               pmap_update(watch->map->pmap);
222                     }
223 
224                     db_watchpoints_inserted = true;
225           }
226 }
227 
228 void
db_clear_watchpoints(void)229 db_clear_watchpoints(void)
230 {
231 
232           db_watchpoints_inserted = false;
233 }
234