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 __P((void));
  58 static void             db_watchpoint_free __P((db_watchpoint_t watch));
  59 static void             db_delete_watchpoint __P((vm_map_t map,
  60                                         db_addr_t addr));
  61 #ifdef notused
  62 static boolean_t        db_find_watchpoint __P((vm_map_t map, db_addr_t addr,
  63                                         db_regs_t *regs));
  64 #endif
  65 static void             db_list_watchpoints __P((void));
  66 static void             db_set_watchpoint __P((vm_map_t map, db_addr_t addr,
  67                                        vm_size_t size));
  68
  69 int  db_md_set_watchpoint   __P((db_expr_t addr, db_expr_t size));
  70 int  db_md_clr_watchpoint   __P((db_expr_t addr, db_expr_t size));
  71 void db_md_list_watchpoints __P((void));
  72
  73
  74 db_watchpoint_t
  75 db_watchpoint_alloc()
  76 {
  77         register 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 void
  94 db_watchpoint_free(watch)
  95         register db_watchpoint_t        watch;
  96 {
  97         watch->link = db_free_watchpoints;
  98         db_free_watchpoints = watch;
  99 }
 100
 101 static void
 102 db_set_watchpoint(map, addr, size)
 103         vm_map_t        map;
 104         db_addr_t       addr;
 105         vm_size_t       size;
 106 {
 107         register db_watchpoint_t        watch;
 108
 109         if (map == NULL) {
 110             db_printf("No map.\n");
 111             return;
 112         }
 113
 114         /*
 115          *      Should we do anything fancy with overlapping regions?
 116          */
 117
 118         for (watch = db_watchpoint_list;
 119              watch != 0;
 120              watch = watch->link)
 121             if (db_map_equal(watch->map, map) &&
 122                 (watch->loaddr == addr) &&
 123                 (watch->hiaddr == addr+size)) {
 124                 db_printf("Already set.\n");
 125                 return;
 126             }
 127
 128         watch = db_watchpoint_alloc();
 129         if (watch == 0) {
 130             db_printf("Too many watchpoints.\n");
 131             return;
 132         }
 133
 134         watch->map = map;
 135         watch->loaddr = addr;
 136         watch->hiaddr = addr+size;
 137
 138         watch->link = db_watchpoint_list;
 139         db_watchpoint_list = watch;
 140
 141         db_watchpoints_inserted = FALSE;
 142 }
 143
 144 static void
 145 db_delete_watchpoint(map, addr)
 146         vm_map_t        map;
 147         db_addr_t       addr;
 148 {
 149         register db_watchpoint_t        watch;
 150         register db_watchpoint_t        *prev;
 151
 152         for (prev = &db_watchpoint_list;
 153              (watch = *prev) != 0;
 154              prev = &watch->link)
 155             if (db_map_equal(watch->map, map) &&
 156                 (watch->loaddr <= addr) &&
 157                 (addr < watch->hiaddr)) {
 158                 *prev = watch->link;
 159                 db_watchpoint_free(watch);
 160                 return;
 161             }
 162
 163         db_printf("Not set.\n");
 164 }
 165
 166 static void
 167 db_list_watchpoints()
 168 {
 169         register db_watchpoint_t        watch;
 170
 171         if (db_watchpoint_list == 0) {
 172             db_printf("No watchpoints set\n");
 173             return;
 174         }
 175
 176         db_printf(" Map        Address  Size\n");
 177         for (watch = db_watchpoint_list;
 178              watch != 0;
 179              watch = watch->link)
 180             db_printf("%s%8p  %8lx  %lx\n",
 181                       db_map_current(watch->map) ? "*" : " ",
 182                       (void *)watch->map, (long)watch->loaddr,
 183                       (long)watch->hiaddr - (long)watch->loaddr);
 184 }
 185
 186 /* Delete watchpoint */
 187 /*ARGSUSED*/
 188 void
 189 db_deletewatch_cmd(addr, have_addr, count, modif)
 190         db_expr_t       addr;
 191         boolean_t       have_addr;
 192         db_expr_t       count;
 193         char *          modif;
 194 {
 195         db_delete_watchpoint(db_map_addr(addr), addr);
 196 }
 197
 198 /* Set watchpoint */
 199 /*ARGSUSED*/
 200 void
 201 db_watchpoint_cmd(addr, have_addr, count, modif)
 202         db_expr_t       addr;
 203         boolean_t       have_addr;
 204         db_expr_t       count;
 205         char *          modif;
 206 {
 207         vm_size_t       size;
 208         db_expr_t       value;
 209
 210         if (db_expression(&value))
 211             size = (vm_size_t) value;
 212         else
 213             size = 4;
 214         db_skip_to_eol();
 215
 216         db_set_watchpoint(db_map_addr(addr), addr, size);
 217 }
 218
 219 /*
 220  * At least one non-optional show-command must be implemented using
 221  * DB_SHOW_COMMAND() so that db_show_cmd_set gets created.  Here is one.
 222  */
 223 DB_SHOW_COMMAND(watches, db_listwatch_cmd)
 224 {
 225         db_list_watchpoints();
 226         db_md_list_watchpoints();
 227 }
 228
 229 void
 230 db_set_watchpoints()
 231 {
 232         register db_watchpoint_t        watch;
 233
 234         if (!db_watchpoints_inserted) {
 235             for (watch = db_watchpoint_list;
 236                  watch != 0;
 237                  watch = watch->link)
 238                 pmap_protect(watch->map->pmap,
 239                              trunc_page(watch->loaddr),
 240                              round_page(watch->hiaddr),
 241                              VM_PROT_READ);
 242
 243             db_watchpoints_inserted = TRUE;
 244         }
 245 }
 246
 247 void
 248 db_clear_watchpoints()
 249 {
 250         db_watchpoints_inserted = FALSE;
 251 }
 252
 253 #ifdef notused
 254 static boolean_t
 255 db_find_watchpoint(map, addr, regs)
 256         vm_map_t        map;
 257         db_addr_t       addr;
 258         db_regs_t       *regs;
 259 {
 260         register db_watchpoint_t watch;
 261         db_watchpoint_t found = 0;
 262
 263         for (watch = db_watchpoint_list;
 264              watch != 0;
 265              watch = watch->link)
 266             if (db_map_equal(watch->map, map)) {
 267                 if ((watch->loaddr <= addr) &&
 268                     (addr < watch->hiaddr))
 269                     return (TRUE);
 270                 else if ((trunc_page(watch->loaddr) <= addr) &&
 271                          (addr < round_page(watch->hiaddr)))
 272                     found = watch;
 273             }
 274
 275         /*
 276          *      We didn't hit exactly on a watchpoint, but we are
 277          *      in a protected region.  We want to single-step
 278          *      and then re-protect.
 279          */
 280
 281         if (found) {
 282             db_watchpoints_inserted = FALSE;
 283             db_single_step(regs);
 284         }
 285
 286         return (FALSE);
 287 }
 288 #endif
 289
 290
 291
 292 /* Delete hardware watchpoint */
 293 /*ARGSUSED*/
 294 void
 295 db_deletehwatch_cmd(addr, have_addr, count, modif)
 296         db_expr_t       addr;
 297         boolean_t       have_addr;
 298         db_expr_t       count;
 299         char *          modif;
 300 {
 301         int rc;
 302
 303         if (count < 0)
 304                 count = 4;
 305
 306         rc = db_md_clr_watchpoint(addr, count);
 307         if (rc < 0)
 308                 db_printf("hardware watchpoint could not be deleted\n");
 309 }
 310
 311 /* Set hardware watchpoint */
 312 /*ARGSUSED*/
 313 void
 314 db_hwatchpoint_cmd(addr, have_addr, count, modif)
 315         db_expr_t       addr;
 316         boolean_t       have_addr;
 317         db_expr_t       count;
 318         char *          modif;
 319 {
 320         int rc;
 321
 322         if (count < 0)
 323                 count = 4;
 324
 325         rc = db_md_set_watchpoint(addr, count);
 326         if (rc < 0)
 327                 db_printf("hardware watchpoint could not be set\n");
 328 }