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 /*
  27  *      Author: Richard P. Draves, Carnegie Mellon University
  28  *      Date:   10/90
  29  */
  30
  31 #include <sys/cdefs.h>
  32 __FBSDID("$FreeBSD$");
  33
  34 #include <sys/param.h>
  35 #include <sys/kernel.h>
  36 #include <sys/lock.h>
  37 #include <sys/proc.h>
  38
  39 #include <vm/vm.h>
  40 #include <vm/pmap.h>
  41 #include <vm/vm_map.h>
  42
  43 #include <ddb/ddb.h>
  44 #include <ddb/db_watch.h>
  45
  46 /*
  47  * Watchpoints.
  48  */
  49
  50 static boolean_t        db_watchpoints_inserted = TRUE;
  51
  52 #define NWATCHPOINTS    100
  53 static struct db_watchpoint     db_watch_table[NWATCHPOINTS];
  54 static db_watchpoint_t  db_next_free_watchpoint = &db_watch_table[0];
  55 static db_watchpoint_t  db_free_watchpoints = 0;
  56 static db_watchpoint_t  db_watchpoint_list = 0;
  57
  58 static db_watchpoint_t  db_watchpoint_alloc(void);
  59 static void             db_watchpoint_free(db_watchpoint_t watch);
  60 static void             db_delete_watchpoint(vm_map_t map, 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 static db_watchpoint_t
  70 db_watchpoint_alloc()
  71 {
  72         register db_watchpoint_t        watch;
  73
  74         if ((watch = db_free_watchpoints) != 0) {
  75             db_free_watchpoints = watch->link;
  76             return (watch);
  77         }
  78         if (db_next_free_watchpoint == &db_watch_table[NWATCHPOINTS]) {
  79             db_printf("All watchpoints used.\n");
  80             return (0);
  81         }
  82         watch = db_next_free_watchpoint;
  83         db_next_free_watchpoint++;
  84
  85         return (watch);
  86 }
  87
  88 static void
  89 db_watchpoint_free(watch)
  90         register db_watchpoint_t        watch;
  91 {
  92         watch->link = db_free_watchpoints;
  93         db_free_watchpoints = watch;
  94 }
  95
  96 static void
  97 db_set_watchpoint(map, addr, size)
  98         vm_map_t        map;
  99         db_addr_t       addr;
 100         vm_size_t       size;
 101 {
 102         register db_watchpoint_t        watch;
 103
 104         if (map == NULL) {
 105             db_printf("No map.\n");
 106             return;
 107         }
 108
 109         /*
 110          *      Should we do anything fancy with overlapping regions?
 111          */
 112
 113         for (watch = db_watchpoint_list;
 114              watch != 0;
 115              watch = watch->link)
 116             if (db_map_equal(watch->map, map) &&
 117                 (watch->loaddr == addr) &&
 118                 (watch->hiaddr == addr+size)) {
 119                 db_printf("Already set.\n");
 120                 return;
 121             }
 122
 123         watch = db_watchpoint_alloc();
 124         if (watch == 0) {
 125             db_printf("Too many watchpoints.\n");
 126             return;
 127         }
 128
 129         watch->map = map;
 130         watch->loaddr = addr;
 131         watch->hiaddr = addr+size;
 132
 133         watch->link = db_watchpoint_list;
 134         db_watchpoint_list = watch;
 135
 136         db_watchpoints_inserted = FALSE;
 137 }
 138
 139 static void
 140 db_delete_watchpoint(map, addr)
 141         vm_map_t        map;
 142         db_addr_t       addr;
 143 {
 144         register db_watchpoint_t        watch;
 145         register db_watchpoint_t        *prev;
 146
 147         for (prev = &db_watchpoint_list;
 148              (watch = *prev) != 0;
 149              prev = &watch->link)
 150             if (db_map_equal(watch->map, map) &&
 151                 (watch->loaddr <= addr) &&
 152                 (addr < watch->hiaddr)) {
 153                 *prev = watch->link;
 154                 db_watchpoint_free(watch);
 155                 return;
 156             }
 157
 158         db_printf("Not set.\n");
 159 }
 160
 161 static void
 162 db_list_watchpoints()
 163 {
 164         register db_watchpoint_t        watch;
 165
 166         if (db_watchpoint_list == 0) {
 167             db_printf("No watchpoints set\n");
 168             return;
 169         }
 170
 171         db_printf(" Map        Address  Size\n");
 172         for (watch = db_watchpoint_list;
 173              watch != 0;
 174              watch = watch->link)
 175             db_printf("%s%8p  %8lx  %lx\n",
 176                       db_map_current(watch->map) ? "*" : " ",
 177                       (void *)watch->map, (long)watch->loaddr,
 178                       (long)watch->hiaddr - (long)watch->loaddr);
 179 }
 180
 181 /* Delete watchpoint */
 182 /*ARGSUSED*/
 183 void
 184 db_deletewatch_cmd(addr, have_addr, count, modif)
 185         db_expr_t       addr;
 186         boolean_t       have_addr;
 187         db_expr_t       count;
 188         char *          modif;
 189 {
 190         db_delete_watchpoint(db_map_addr(addr), addr);
 191 }
 192
 193 /* Set watchpoint */
 194 /*ARGSUSED*/
 195 void
 196 db_watchpoint_cmd(addr, have_addr, count, modif)
 197         db_expr_t       addr;
 198         boolean_t       have_addr;
 199         db_expr_t       count;
 200         char *          modif;
 201 {
 202         vm_size_t       size;
 203         db_expr_t       value;
 204
 205         if (db_expression(&value))
 206             size = (vm_size_t) value;
 207         else
 208             size = 4;
 209         db_skip_to_eol();
 210
 211         db_set_watchpoint(db_map_addr(addr), addr, size);
 212 }
 213
 214 /*
 215  * At least one non-optional show-command must be implemented using
 216  * DB_SHOW_COMMAND() so that db_show_cmd_set gets created.  Here is one.
 217  */
 218 DB_SHOW_COMMAND(watches, db_listwatch_cmd)
 219 {
 220         db_list_watchpoints();
 221         db_md_list_watchpoints();
 222 }
 223
 224 void
 225 db_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
 242 void
 243 db_clear_watchpoints()
 244 {
 245         db_watchpoints_inserted = FALSE;
 246 }
 247
 248 #ifdef notused
 249 static boolean_t
 250 db_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
 285
 286
 287 /* Delete hardware watchpoint */
 288 /*ARGSUSED*/
 289 void
 290 db_deletehwatch_cmd(addr, have_addr, count, modif)
 291         db_expr_t       addr;
 292         boolean_t       have_addr;
 293         db_expr_t       count;
 294         char *          modif;
 295 {
 296         int rc;
 297
 298         if (count < 0)
 299                 count = 4;
 300
 301         rc = db_md_clr_watchpoint(addr, count);
 302         if (rc < 0)
 303                 db_printf("hardware watchpoint could not be deleted\n");
 304 }
 305
 306 /* Set hardware watchpoint */
 307 /*ARGSUSED*/
 308 void
 309 db_hwatchpoint_cmd(addr, have_addr, count, modif)
 310         db_expr_t       addr;
 311         boolean_t       have_addr;
 312         db_expr_t       count;
 313         char *          modif;
 314 {
 315         int rc;
 316
 317         if (count < 0)
 318                 count = 4;
 319
 320         rc = db_md_set_watchpoint(addr, count);
 321         if (rc < 0)
 322                 db_printf("hardware watchpoint could not be set\n");
 323 }