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(void)
  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(db_watchpoint_t watch)
  90 {
  91         watch->link = db_free_watchpoints;
  92         db_free_watchpoints = watch;
  93 }
  94
  95 static void
  96 db_set_watchpoint(vm_map_t map, db_addr_t addr, vm_size_t size)
  97 {
  98         register db_watchpoint_t        watch;
  99
 100         if (map == NULL) {
 101             db_printf("No map.\n");
 102             return;
 103         }
 104
 105         /*
 106          *      Should we do anything fancy with overlapping regions?
 107          */
 108
 109         for (watch = db_watchpoint_list;
 110              watch != 0;
 111              watch = watch->link)
 112             if (db_map_equal(watch->map, map) &&
 113                 (watch->loaddr == addr) &&
 114                 (watch->hiaddr == addr+size)) {
 115                 db_printf("Already set.\n");
 116                 return;
 117             }
 118
 119         watch = db_watchpoint_alloc();
 120         if (watch == 0) {
 121             db_printf("Too many watchpoints.\n");
 122             return;
 123         }
 124
 125         watch->map = map;
 126         watch->loaddr = addr;
 127         watch->hiaddr = addr+size;
 128
 129         watch->link = db_watchpoint_list;
 130         db_watchpoint_list = watch;
 131
 132         db_watchpoints_inserted = FALSE;
 133 }
 134
 135 static void
 136 db_delete_watchpoint(vm_map_t map, db_addr_t addr)
 137 {
 138         register db_watchpoint_t        watch;
 139         register db_watchpoint_t        *prev;
 140
 141         for (prev = &db_watchpoint_list;
 142              (watch = *prev) != 0;
 143              prev = &watch->link)
 144             if (db_map_equal(watch->map, map) &&
 145                 (watch->loaddr <= addr) &&
 146                 (addr < watch->hiaddr)) {
 147                 *prev = watch->link;
 148                 db_watchpoint_free(watch);
 149                 return;
 150             }
 151
 152         db_printf("Not set.\n");
 153 }
 154
 155 static void
 156 db_list_watchpoints(void)
 157 {
 158         register db_watchpoint_t        watch;
 159
 160         if (db_watchpoint_list == 0) {
 161             db_printf("No watchpoints set\n");
 162             return;
 163         }
 164
 165 #ifdef __LP64__
 166         db_printf(" Map                Address          Size\n");
 167 #else
 168         db_printf(" Map        Address  Size\n");
 169 #endif
 170         for (watch = db_watchpoint_list;
 171              watch != 0;
 172              watch = watch->link)
 173 #ifdef __LP64__
 174             db_printf("%s%16p  %16lx  %lx\n",
 175 #else
 176             db_printf("%s%8p  %8lx  %lx\n",
 177 #endif
 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*/
 185 void
 186 db_deletewatch_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 187    char *modif)
 188 {
 189         db_delete_watchpoint(db_map_addr(addr), addr);
 190 }
 191
 192 /* Set watchpoint */
 193 /*ARGSUSED*/
 194 void
 195 db_watchpoint_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 196    char *modif)
 197 {
 198         vm_size_t       size;
 199         db_expr_t       value;
 200
 201         if (db_expression(&value))
 202             size = (vm_size_t) value;
 203         else
 204             size = 4;
 205         db_skip_to_eol();
 206
 207         db_set_watchpoint(db_map_addr(addr), addr, size);
 208 }
 209
 210 /*
 211  * At least one non-optional show-command must be implemented using
 212  * DB_SHOW_COMMAND() so that db_show_cmd_set gets created.  Here is one.
 213  */
 214 DB_SHOW_COMMAND(watches, db_listwatch_cmd)
 215 {
 216         db_list_watchpoints();
 217         db_md_list_watchpoints();
 218 }
 219
 220 void
 221 db_set_watchpoints(void)
 222 {
 223         register db_watchpoint_t        watch;
 224
 225         if (!db_watchpoints_inserted) {
 226             for (watch = db_watchpoint_list;
 227                  watch != 0;
 228                  watch = watch->link)
 229                 pmap_protect(watch->map->pmap,
 230                              trunc_page(watch->loaddr),
 231                              round_page(watch->hiaddr),
 232                              VM_PROT_READ);
 233
 234             db_watchpoints_inserted = TRUE;
 235         }
 236 }
 237
 238 void
 239 db_clear_watchpoints(void)
 240 {
 241         db_watchpoints_inserted = FALSE;
 242 }
 243
 244 #ifdef notused
 245 static boolean_t
 246 db_find_watchpoint(vm_map_t map, db_addr_t addr, db_regs_t regs)
 247 {
 248         register db_watchpoint_t watch;
 249         db_watchpoint_t found = 0;
 250
 251         for (watch = db_watchpoint_list;
 252              watch != 0;
 253              watch = watch->link)
 254             if (db_map_equal(watch->map, map)) {
 255                 if ((watch->loaddr <= addr) &&
 256                     (addr < watch->hiaddr))
 257                     return (TRUE);
 258                 else if ((trunc_page(watch->loaddr) <= addr) &&
 259                          (addr < round_page(watch->hiaddr)))
 260                     found = watch;
 261             }
 262
 263         /*
 264          *      We didn't hit exactly on a watchpoint, but we are
 265          *      in a protected region.  We want to single-step
 266          *      and then re-protect.
 267          */
 268
 269         if (found) {
 270             db_watchpoints_inserted = FALSE;
 271             db_single_step(regs);
 272         }
 273
 274         return (FALSE);
 275 }
 276 #endif
 277
 278
 279
 280 /* Delete hardware watchpoint */
 281 /*ARGSUSED*/
 282 void
 283 db_deletehwatch_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 284    char *modif)
 285 {
 286         int rc;
 287
 288         if (count < 0)
 289                 count = 4;
 290
 291         rc = db_md_clr_watchpoint(addr, count);
 292         if (rc < 0)
 293                 db_printf("hardware watchpoint could not be deleted\n");
 294 }
 295
 296 /* Set hardware watchpoint */
 297 /*ARGSUSED*/
 298 void
 299 db_hwatchpoint_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 300    char *modif)
 301 {
 302         int rc;
 303
 304         if (count < 0)
 305                 count = 4;
 306
 307         rc = db_md_set_watchpoint(addr, count);
 308         if (rc < 0)
 309                 db_printf("hardware watchpoint could not be set\n");
 310 }