sys/ddb/db_watch.c

   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: src/sys/ddb/db_watch.c,v 1.20.2.1 2001/07/25 01:00:08 bsd 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
  42 #include <ddb/ddb.h>
  43 #include <ddb/db_watch.h>
  44
  45 /*
  46  * Watchpoints.
  47  */
  48
  49 static boolean_t        db_watchpoints_inserted = TRUE;
  50
  51 #define NWATCHPOINTS    100
  52 static struct db_watchpoint     db_watch_table[NWATCHPOINTS];
  53 static db_watchpoint_t  db_next_free_watchpoint = &db_watch_table[0];
  54 static db_watchpoint_t  db_free_watchpoints = 0;
  55 static db_watchpoint_t  db_watchpoint_list = 0;
  56
  57 static db_watchpoint_t  db_watchpoint_alloc (void);
  58 static void             db_watchpoint_free (db_watchpoint_t watch);
  59 static void             db_delete_watchpoint (vm_map_t map,
  60                                         db_addr_t addr);
  61 #ifdef notused
  62 static boolean_t        db_find_watchpoint (vm_map_t map, db_addr_t addr,
  63                                         db_regs_t *regs);
  64 #endif
  65 static void             db_list_watchpoints (void);
  66 static void             db_set_watchpoint (vm_map_t map, db_addr_t addr,
  67                                        vm_size_t size);
  68
  69 int  db_md_set_watchpoint   (db_expr_t addr, db_expr_t size);
  70 int  db_md_clr_watchpoint   (db_expr_t addr, db_expr_t size);
  71 void db_md_list_watchpoints (void);
  72
  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         db_printf(" Map        Address  Size\n");
 171         for (watch = db_watchpoint_list;
 172              watch != 0;
 173              watch = watch->link)
 174             db_printf("%s%8p  %8lx  %lx\n",
 175                       db_map_current(watch->map) ? "*" : " ",
 176                       (void *)watch->map, (long)watch->loaddr,
 177                       (long)watch->hiaddr - (long)watch->loaddr);
 178 }
 179
 180 /* Delete watchpoint */
 181 /*ARGSUSED*/
 182 void
 183 db_deletewatch_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 184                    char *modif)
 185 {
 186         db_delete_watchpoint(db_map_addr(addr), addr);
 187 }
 188
 189 /* Set watchpoint */
 190 /*ARGSUSED*/
 191 void
 192 db_watchpoint_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 193                   char *modif)
 194 {
 195         vm_size_t       size;
 196         db_expr_t       value;
 197
 198         if (db_expression(&value))
 199             size = (vm_size_t) value;
 200         else
 201             size = 4;
 202         db_skip_to_eol();
 203
 204         db_set_watchpoint(db_map_addr(addr), addr, size);
 205 }
 206
 207 /*
 208  * At least one non-optional show-command must be implemented using
 209  * DB_SHOW_COMMAND() so that db_show_cmd_set gets created.  Here is one.
 210  */
 211 DB_SHOW_COMMAND(watches, db_listwatch_cmd)
 212 {
 213         db_list_watchpoints();
 214         db_md_list_watchpoints();
 215 }
 216
 217 void
 218 db_set_watchpoints(void)
 219 {
 220         db_watchpoint_t watch;
 221
 222         if (!db_watchpoints_inserted) {
 223             for (watch = db_watchpoint_list;
 224                  watch != 0;
 225                  watch = watch->link)
 226                 pmap_protect(watch->map->pmap,
 227                              trunc_page(watch->loaddr),
 228                              round_page(watch->hiaddr),
 229                              VM_PROT_READ);
 230
 231             db_watchpoints_inserted = TRUE;
 232         }
 233 }
 234
 235 void
 236 db_clear_watchpoints(void)
 237 {
 238         db_watchpoints_inserted = FALSE;
 239 }
 240
 241 #ifdef notused
 242 static boolean_t
 243 db_find_watchpoint(vm_map_t map, db_addr_t addr, db_regs_t *regs)
 244 {
 245         db_watchpoint_t watch;
 246         db_watchpoint_t found = 0;
 247
 248         for (watch = db_watchpoint_list;
 249              watch != 0;
 250              watch = watch->link)
 251             if (db_map_equal(watch->map, map)) {
 252                 if ((watch->loaddr <= addr) &&
 253                     (addr < watch->hiaddr))
 254                     return (TRUE);
 255                 else if ((trunc_page(watch->loaddr) <= addr) &&
 256                          (addr < round_page(watch->hiaddr)))
 257                     found = watch;
 258             }
 259
 260         /*
 261          *      We didn't hit exactly on a watchpoint, but we are
 262          *      in a protected region.  We want to single-step
 263          *      and then re-protect.
 264          */
 265
 266         if (found) {
 267             db_watchpoints_inserted = FALSE;
 268             db_single_step(regs);
 269         }
 270
 271         return (FALSE);
 272 }
 273 #endif
 274
 275
 276
 277 /* Delete hardware watchpoint */
 278 /*ARGSUSED*/
 279 void
 280 db_deletehwatch_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 281                     char *modif)
 282 {
 283         int rc;
 284
 285         if (count < 0)
 286                 count = 4;
 287
 288         rc = db_md_clr_watchpoint(addr, count);
 289         if (rc < 0)
 290                 db_printf("hardware watchpoint could not be deleted\n");
 291 }
 292
 293 /* Set hardware watchpoint */
 294 /*ARGSUSED*/
 295 void
 296 db_hwatchpoint_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 297                    char *modif)
 298 {
 299         int rc;
 300
 301         if (count < 0)
 302                 count = 4;
 303
 304         rc = db_md_set_watchpoint(addr, count);
 305         if (rc < 0)
 306                 db_printf("hardware watchpoint could not be set\n");
 307 }