db_watch.c revision 48407 
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 *	$Id: db_watch.c,v 1.17 1998/07/08 06:43:57 bde Exp $
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#include <vm/vm_prot.h>
42
43#include <ddb/ddb.h>
44#include <ddb/db_watch.h>
45
46/*
47 * Watchpoints.
48 */
49
50static boolean_t	db_watchpoints_inserted = TRUE;
51
52#define	NWATCHPOINTS	100
53static struct db_watchpoint	db_watch_table[NWATCHPOINTS];
54static db_watchpoint_t	db_next_free_watchpoint = &db_watch_table[0];
55static db_watchpoint_t	db_free_watchpoints = 0;
56static db_watchpoint_t	db_watchpoint_list = 0;
57
58static db_watchpoint_t	db_watchpoint_alloc __P((void));
59static void		db_watchpoint_free __P((db_watchpoint_t watch));
60static void		db_delete_watchpoint __P((vm_map_t map,
61					db_addr_t addr));
62#ifdef notused
63static boolean_t	db_find_watchpoint __P((vm_map_t map, db_addr_t addr,
64					db_regs_t *regs));
65#endif
66static void		db_list_watchpoints __P((void));
67static void		db_set_watchpoint __P((vm_map_t map, db_addr_t addr,
68				       vm_size_t size));
69
70
71db_watchpoint_t
72db_watchpoint_alloc()
73{
74	register db_watchpoint_t	watch;
75
76	if ((watch = db_free_watchpoints) != 0) {
77	    db_free_watchpoints = watch->link;
78	    return (watch);
79	}
80	if (db_next_free_watchpoint == &db_watch_table[NWATCHPOINTS]) {
81	    db_printf("All watchpoints used.\n");
82	    return (0);
83	}
84	watch = db_next_free_watchpoint;
85	db_next_free_watchpoint++;
86
87	return (watch);
88}
89
90void
91db_watchpoint_free(watch)
92	register db_watchpoint_t	watch;
93{
94	watch->link = db_free_watchpoints;
95	db_free_watchpoints = watch;
96}
97
98static void
99db_set_watchpoint(map, addr, size)
100	vm_map_t	map;
101	db_addr_t	addr;
102	vm_size_t	size;
103{
104	register db_watchpoint_t	watch;
105
106	if (map == NULL) {
107	    db_printf("No map.\n");
108	    return;
109	}
110
111	/*
112	 *	Should we do anything fancy with overlapping regions?
113	 */
114
115	for (watch = db_watchpoint_list;
116	     watch != 0;
117	     watch = watch->link)
118	    if (db_map_equal(watch->map, map) &&
119		(watch->loaddr == addr) &&
120		(watch->hiaddr == addr+size)) {
121		db_printf("Already set.\n");
122		return;
123	    }
124
125	watch = db_watchpoint_alloc();
126	if (watch == 0) {
127	    db_printf("Too many watchpoints.\n");
128	    return;
129	}
130
131	watch->map = map;
132	watch->loaddr = addr;
133	watch->hiaddr = addr+size;
134
135	watch->link = db_watchpoint_list;
136	db_watchpoint_list = watch;
137
138	db_watchpoints_inserted = FALSE;
139}
140
141static void
142db_delete_watchpoint(map, addr)
143	vm_map_t	map;
144	db_addr_t	addr;
145{
146	register db_watchpoint_t	watch;
147	register db_watchpoint_t	*prev;
148
149	for (prev = &db_watchpoint_list;
150	     (watch = *prev) != 0;
151	     prev = &watch->link)
152	    if (db_map_equal(watch->map, map) &&
153		(watch->loaddr <= addr) &&
154		(addr < watch->hiaddr)) {
155		*prev = watch->link;
156		db_watchpoint_free(watch);
157		return;
158	    }
159
160	db_printf("Not set.\n");
161}
162
163static void
164db_list_watchpoints()
165{
166	register db_watchpoint_t	watch;
167
168	if (db_watchpoint_list == 0) {
169	    db_printf("No watchpoints set\n");
170	    return;
171	}
172
173	db_printf(" Map        Address  Size\n");
174	for (watch = db_watchpoint_list;
175	     watch != 0;
176	     watch = watch->link)
177	    db_printf("%s%8p  %8lx  %lx\n",
178		      db_map_current(watch->map) ? "*" : " ",
179		      (void *)watch->map, (long)watch->loaddr,
180		      (long)watch->hiaddr - (long)watch->loaddr);
181}
182
183/* Delete watchpoint */
184/*ARGSUSED*/
185void
186db_deletewatch_cmd(addr, have_addr, count, modif)
187	db_expr_t	addr;
188	boolean_t	have_addr;
189	db_expr_t	count;
190	char *		modif;
191{
192	db_delete_watchpoint(db_map_addr(addr), addr);
193}
194
195/* Set watchpoint */
196/*ARGSUSED*/
197void
198db_watchpoint_cmd(addr, have_addr, count, modif)
199	db_expr_t	addr;
200	boolean_t	have_addr;
201	db_expr_t	count;
202	char *		modif;
203{
204	vm_size_t	size;
205	db_expr_t	value;
206
207	if (db_expression(&value))
208	    size = (vm_size_t) value;
209	else
210	    size = 4;
211	db_skip_to_eol();
212
213	db_set_watchpoint(db_map_addr(addr), addr, size);
214}
215
216/*
217 * At least one non-optional show-command must be implemented using
218 * DB_SHOW_COMMAND() so that db_show_cmd_set gets created.  Here is one.
219 */
220DB_SHOW_COMMAND(watches, db_listwatch_cmd)
221{
222	db_list_watchpoints();
223}
224
225void
226db_set_watchpoints()
227{
228	register 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
243void
244db_clear_watchpoints()
245{
246	db_watchpoints_inserted = FALSE;
247}
248
249#ifdef notused
250static boolean_t
251db_find_watchpoint(map, addr, regs)
252	vm_map_t	map;
253	db_addr_t	addr;
254	db_regs_t	*regs;
255{
256	register db_watchpoint_t watch;
257	db_watchpoint_t found = 0;
258
259	for (watch = db_watchpoint_list;
260	     watch != 0;
261	     watch = watch->link)
262	    if (db_map_equal(watch->map, map)) {
263		if ((watch->loaddr <= addr) &&
264		    (addr < watch->hiaddr))
265		    return (TRUE);
266		else if ((trunc_page(watch->loaddr) <= addr) &&
267			 (addr < round_page(watch->hiaddr)))
268		    found = watch;
269	    }
270
271	/*
272	 *	We didn't hit exactly on a watchpoint, but we are
273	 *	in a protected region.  We want to single-step
274	 *	and then re-protect.
275	 */
276
277	if (found) {
278	    db_watchpoints_inserted = FALSE;
279	    db_single_step(regs);
280	}
281
282	return (FALSE);
283}
284#endif
285