FreeBSD/Linux Kernel Cross Reference
sys/ddb/db_watch.c
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 * Author: Richard P. Draves, Carnegie Mellon University
30 * Date: 10/90
31 */
32
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35
36 #include <sys/param.h>
37 #include <sys/kdb.h>
38 #include <sys/kernel.h>
39 #include <sys/lock.h>
40 #include <sys/proc.h>
41
42 #include <vm/vm.h>
43 #include <vm/pmap.h>
44 #include <vm/vm_map.h>
45
46 #include <machine/kdb.h>
47
48 #include <ddb/ddb.h>
49 #include <ddb/db_watch.h>
50
51 /*
52 * Watchpoints.
53 */
54
55 static bool db_watchpoints_inserted = true;
56
57 #define NWATCHPOINTS 100
58 static struct db_watchpoint db_watch_table[NWATCHPOINTS];
59 static db_watchpoint_t db_next_free_watchpoint = &db_watch_table[0];
60 static db_watchpoint_t db_free_watchpoints = 0;
61 static db_watchpoint_t db_watchpoint_list = 0;
62
63 static db_watchpoint_t db_watchpoint_alloc(void);
64 static void db_watchpoint_free(db_watchpoint_t watch);
65 static void db_delete_watchpoint(vm_map_t map, db_addr_t addr);
66 #ifdef notused
67 static bool db_find_watchpoint(vm_map_t map, db_addr_t addr,
68 db_regs_t *regs);
69 #endif
70 static void db_list_watchpoints(void);
71 static void db_set_watchpoint(vm_map_t map, db_addr_t addr,
72 vm_size_t size);
73
74 static db_watchpoint_t
75 db_watchpoint_alloc(void)
76 {
77 db_watchpoint_t watch;
78
79 if ((watch = db_free_watchpoints) != 0) {
80 db_free_watchpoints = watch->link;
81 return (watch);
82 }
83 if (db_next_free_watchpoint == &db_watch_table[NWATCHPOINTS]) {
84 db_printf("All watchpoints used.\n");
85 return (0);
86 }
87 watch = db_next_free_watchpoint;
88 db_next_free_watchpoint++;
89
90 return (watch);
91 }
92
93 static void
94 db_watchpoint_free(db_watchpoint_t watch)
95 {
96 watch->link = db_free_watchpoints;
97 db_free_watchpoints = watch;
98 }
99
100 static void
101 db_set_watchpoint(vm_map_t map, db_addr_t addr, vm_size_t size)
102 {
103 db_watchpoint_t watch;
104
105 if (map == NULL) {
106 db_printf("No map.\n");
107 return;
108 }
109
110 /*
111 * Should we do anything fancy with overlapping regions?
112 */
113
114 for (watch = db_watchpoint_list;
115 watch != 0;
116 watch = watch->link)
117 if (db_map_equal(watch->map, map) &&
118 (watch->loaddr == addr) &&
119 (watch->hiaddr == addr+size)) {
120 db_printf("Already set.\n");
121 return;
122 }
123
124 watch = db_watchpoint_alloc();
125 if (watch == 0) {
126 db_printf("Too many watchpoints.\n");
127 return;
128 }
129
130 watch->map = map;
131 watch->loaddr = addr;
132 watch->hiaddr = addr+size;
133
134 watch->link = db_watchpoint_list;
135 db_watchpoint_list = watch;
136
137 db_watchpoints_inserted = false;
138 }
139
140 static void
141 db_delete_watchpoint(vm_map_t map, db_addr_t addr)
142 {
143 db_watchpoint_t watch;
144 db_watchpoint_t *prev;
145
146 for (prev = &db_watchpoint_list;
147 (watch = *prev) != 0;
148 prev = &watch->link)
149 if (db_map_equal(watch->map, map) &&
150 (watch->loaddr <= addr) &&
151 (addr < watch->hiaddr)) {
152 *prev = watch->link;
153 db_watchpoint_free(watch);
154 return;
155 }
156
157 db_printf("Not set.\n");
158 }
159
160 static void
161 db_list_watchpoints(void)
162 {
163 db_watchpoint_t watch;
164
165 if (db_watchpoint_list == 0) {
166 db_printf("No watchpoints set\n");
167 return;
168 }
169
170 #ifdef __LP64__
171 db_printf(" Map Address Size\n");
172 #else
173 db_printf(" Map Address Size\n");
174 #endif
175 for (watch = db_watchpoint_list;
176 watch != 0;
177 watch = watch->link)
178 #ifdef __LP64__
179 db_printf("%s%16p %16lx %lx\n",
180 #else
181 db_printf("%s%8p %8lx %lx\n",
182 #endif
183 db_map_current(watch->map) ? "*" : " ",
184 (void *)watch->map, (long)watch->loaddr,
185 (long)watch->hiaddr - (long)watch->loaddr);
186 }
187
188 /* Delete watchpoint */
189 /*ARGSUSED*/
190 void
191 db_deletewatch_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
192 char *modif)
193 {
194 db_delete_watchpoint(db_map_addr(addr), addr);
195 }
196
197 /* Set watchpoint */
198 /*ARGSUSED*/
199 void
200 db_watchpoint_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
201 char *modif)
202 {
203 vm_size_t size;
204 db_expr_t value;
205
206 if (db_expression(&value))
207 size = (vm_size_t) value;
208 else
209 size = 4;
210 db_skip_to_eol();
211
212 db_set_watchpoint(db_map_addr(addr), addr, size);
213 }
214
215 /*
216 * At least one non-optional show-command must be implemented using
217 * DB_SHOW_COMMAND() so that db_show_cmd_set gets created. Here is one.
218 */
219 DB_SHOW_COMMAND_FLAGS(watches, db_listwatch_cmd, DB_CMD_MEMSAFE)
220 {
221 db_list_watchpoints();
222 db_md_list_watchpoints();
223 }
224
225 void
226 db_set_watchpoints(void)
227 {
228 db_watchpoint_t watch;
229
230 if (!db_watchpoints_inserted) {
231 for (watch = db_watchpoint_list;
232 watch != 0;
233 watch = watch->link)
234 pmap_protect(watch->map->pmap,
235 trunc_page(watch->loaddr),
236 round_page(watch->hiaddr),
237 VM_PROT_READ);
238
239 db_watchpoints_inserted = true;
240 }
241 }
242
243 void
244 db_clear_watchpoints(void)
245 {
246 db_watchpoints_inserted = false;
247 }
248
249 #ifdef notused
250 static bool
251 db_find_watchpoint(vm_map_t map, db_addr_t addr, db_regs_t regs)
252 {
253 db_watchpoint_t watch;
254 db_watchpoint_t found = 0;
255
256 for (watch = db_watchpoint_list;
257 watch != 0;
258 watch = watch->link)
259 if (db_map_equal(watch->map, map)) {
260 if ((watch->loaddr <= addr) &&
261 (addr < watch->hiaddr))
262 return (true);
263 else if ((trunc_page(watch->loaddr) <= addr) &&
264 (addr < round_page(watch->hiaddr)))
265 found = watch;
266 }
267
268 /*
269 * We didn't hit exactly on a watchpoint, but we are
270 * in a protected region. We want to single-step
271 * and then re-protect.
272 */
273
274 if (found) {
275 db_watchpoints_inserted = false;
276 db_single_step(regs);
277 }
278
279 return (false);
280 }
281 #endif
282
283 /* Delete hardware watchpoint */
284 void
285 db_deletehwatch_cmd(db_expr_t addr, bool have_addr, db_expr_t size,
286 char *modif)
287 {
288 int rc;
289
290 if (size < 0)
291 size = 4;
292
293 rc = kdb_cpu_clr_watchpoint((vm_offset_t)addr, (vm_size_t)size);
294 switch (rc) {
295 case ENXIO:
296 /* Not supported, ignored. */
297 break;
298 case EINVAL:
299 db_printf("Invalid watchpoint address or size.\n");
300 break;
301 default:
302 if (rc != 0)
303 db_printf("Hardware watchpoint could not be deleted, "
304 "status=%d\n", rc);
305 break;
306 }
307 }
308
309 /* Set hardware watchpoint */
310 void
311 db_hwatchpoint_cmd(db_expr_t addr, bool have_addr, db_expr_t size,
312 char *modif)
313 {
314 int rc;
315
316 if (size < 0)
317 size = 4;
318
319 rc = kdb_cpu_set_watchpoint((vm_offset_t)addr, (vm_size_t)size,
320 KDB_DBG_ACCESS_W);
321
322 switch (rc) {
323 case EINVAL:
324 db_printf("Invalid watchpoint size or address.\n");
325 break;
326 case EBUSY:
327 db_printf("No hardware watchpoints available.\n");
328 break;
329 case ENXIO:
330 db_printf("Hardware watchpoints are not supported on this platform.\n");
331 break;
332 default:
333 if (rc != 0)
334 db_printf("Could not set hardware watchpoint, "
335 "status=%d\n", rc);
336 }
337 }
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