db_watch.c revision 52635 
1/*
2 * Mach Operating System
3 * Copyright (c) 1991,1990 Carnegie Mellon University
4 * All Rights Reserved.
5 *
6 * Permission to use, copy, modify and distribute this software and its
7 * documentation is hereby granted, provided that both the copyright
8 * notice and this permission notice appear in all copies of the
9 * software, derivative works or modified versions, and any portions
10 * thereof, and that both notices appear in supporting documentation.
11 *
12 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
13 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
14 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
15 *
16 * Carnegie Mellon requests users of this software to return to
17 *
18 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
19 *  School of Computer Science
20 *  Carnegie Mellon University
21 *  Pittsburgh PA 15213-3890
22 *
23 * any improvements or extensions that they make and grant Carnegie the
24 * rights to redistribute these changes.
25 *
26 * $FreeBSD: head/sys/ddb/db_watch.c 52635 1999-10-29 18:09:36Z phk $
27 */
28
29/*
30 * 	Author: Richard P. Draves, Carnegie Mellon University
31 *	Date:	10/90
32 */
33
34#include <sys/param.h>
35#include <sys/kernel.h>
36
37#include <vm/vm.h>
38#include <sys/lock.h>
39#include <vm/pmap.h>
40#include <vm/vm_map.h>
41
42#include <ddb/ddb.h>
43#include <ddb/db_watch.h>
44
45/*
46 * Watchpoints.
47 */
48
49static boolean_t	db_watchpoints_inserted = TRUE;
50
51#define	NWATCHPOINTS	100
52static struct db_watchpoint	db_watch_table[NWATCHPOINTS];
53static db_watchpoint_t	db_next_free_watchpoint = &db_watch_table[0];
54static db_watchpoint_t	db_free_watchpoints = 0;
55static db_watchpoint_t	db_watchpoint_list = 0;
56
57static db_watchpoint_t	db_watchpoint_alloc __P((void));
58static void		db_watchpoint_free __P((db_watchpoint_t watch));
59static void		db_delete_watchpoint __P((vm_map_t map,
60					db_addr_t addr));
61#ifdef notused
62static boolean_t	db_find_watchpoint __P((vm_map_t map, db_addr_t addr,
63					db_regs_t *regs));
64#endif
65static void		db_list_watchpoints __P((void));
66static void		db_set_watchpoint __P((vm_map_t map, db_addr_t addr,
67				       vm_size_t size));
68
69
70db_watchpoint_t
71db_watchpoint_alloc()
72{
73	register db_watchpoint_t	watch;
74
75	if ((watch = db_free_watchpoints) != 0) {
76	    db_free_watchpoints = watch->link;
77	    return (watch);
78	}
79	if (db_next_free_watchpoint == &db_watch_table[NWATCHPOINTS]) {
80	    db_printf("All watchpoints used.\n");
81	    return (0);
82	}
83	watch = db_next_free_watchpoint;
84	db_next_free_watchpoint++;
85
86	return (watch);
87}
88
89void
90db_watchpoint_free(watch)
91	register db_watchpoint_t	watch;
92{
93	watch->link = db_free_watchpoints;
94	db_free_watchpoints = watch;
95}
96
97static void
98db_set_watchpoint(map, addr, size)
99	vm_map_t	map;
100	db_addr_t	addr;
101	vm_size_t	size;
102{
103	register 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
140static void
141db_delete_watchpoint(map, addr)
142	vm_map_t	map;
143	db_addr_t	addr;
144{
145	register db_watchpoint_t	watch;
146	register db_watchpoint_t	*prev;
147
148	for (prev = &db_watchpoint_list;
149	     (watch = *prev) != 0;
150	     prev = &watch->link)
151	    if (db_map_equal(watch->map, map) &&
152		(watch->loaddr <= addr) &&
153		(addr < watch->hiaddr)) {
154		*prev = watch->link;
155		db_watchpoint_free(watch);
156		return;
157	    }
158
159	db_printf("Not set.\n");
160}
161
162static void
163db_list_watchpoints()
164{
165	register db_watchpoint_t	watch;
166
167	if (db_watchpoint_list == 0) {
168	    db_printf("No watchpoints set\n");
169	    return;
170	}
171
172	db_printf(" Map        Address  Size\n");
173	for (watch = db_watchpoint_list;
174	     watch != 0;
175	     watch = watch->link)
176	    db_printf("%s%8p  %8lx  %lx\n",
177		      db_map_current(watch->map) ? "*" : " ",
178		      (void *)watch->map, (long)watch->loaddr,
179		      (long)watch->hiaddr - (long)watch->loaddr);
180}
181
182/* Delete watchpoint */
183/*ARGSUSED*/
184void
185db_deletewatch_cmd(addr, have_addr, count, modif)
186	db_expr_t	addr;
187	boolean_t	have_addr;
188	db_expr_t	count;
189	char *		modif;
190{
191	db_delete_watchpoint(db_map_addr(addr), addr);
192}
193
194/* Set watchpoint */
195/*ARGSUSED*/
196void
197db_watchpoint_cmd(addr, have_addr, count, modif)
198	db_expr_t	addr;
199	boolean_t	have_addr;
200	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 */
219DB_SHOW_COMMAND(watches, db_listwatch_cmd)
220{
221	db_list_watchpoints();
222}
223
224void
225db_set_watchpoints()
226{
227	register db_watchpoint_t	watch;
228
229	if (!db_watchpoints_inserted) {
230	    for (watch = db_watchpoint_list;
231	         watch != 0;
232	         watch = watch->link)
233		pmap_protect(watch->map->pmap,
234			     trunc_page(watch->loaddr),
235			     round_page(watch->hiaddr),
236			     VM_PROT_READ);
237
238	    db_watchpoints_inserted = TRUE;
239	}
240}
241
242void
243db_clear_watchpoints()
244{
245	db_watchpoints_inserted = FALSE;
246}
247
248#ifdef notused
249static boolean_t
250db_find_watchpoint(map, addr, regs)
251	vm_map_t	map;
252	db_addr_t	addr;
253	db_regs_t	*regs;
254{
255	register db_watchpoint_t watch;
256	db_watchpoint_t found = 0;
257
258	for (watch = db_watchpoint_list;
259	     watch != 0;
260	     watch = watch->link)
261	    if (db_map_equal(watch->map, map)) {
262		if ((watch->loaddr <= addr) &&
263		    (addr < watch->hiaddr))
264		    return (TRUE);
265		else if ((trunc_page(watch->loaddr) <= addr) &&
266			 (addr < round_page(watch->hiaddr)))
267		    found = watch;
268	    }
269
270	/*
271	 *	We didn't hit exactly on a watchpoint, but we are
272	 *	in a protected region.  We want to single-step
273	 *	and then re-protect.
274	 */
275
276	if (found) {
277	    db_watchpoints_inserted = FALSE;
278	    db_single_step(regs);
279	}
280
281	return (FALSE);
282}
283#endif
284