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  * $DragonFly: src/sys/ddb/db_watch.c,v 1.4 2003/08/27 10:47:13 rob Exp $
  28  */
  29
  30 /*
  31  *      Author: Richard P. Draves, Carnegie Mellon University
  32  *      Date:   10/90
  33  */
  34
  35 #include <sys/param.h>
  36 #include <sys/kernel.h>
  37
  38 #include <vm/vm.h>
  39 #include <sys/lock.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,
  61                                         db_addr_t addr);
  62 #ifdef notused
  63 static boolean_t        db_find_watchpoint (vm_map_t map, db_addr_t addr,
  64                                         db_regs_t *regs);
  65 #endif
  66 static void             db_list_watchpoints (void);
  67 static void             db_set_watchpoint (vm_map_t map, db_addr_t addr,
  68                                        vm_size_t size);
  69
  70 int  db_md_set_watchpoint   (db_expr_t addr, db_expr_t size);
  71 int  db_md_clr_watchpoint   (db_expr_t addr, db_expr_t size);
  72 void db_md_list_watchpoints (void);
  73
  74
  75 db_watchpoint_t
  76 db_watchpoint_alloc()
  77 {
  78         db_watchpoint_t watch;
  79
  80         if ((watch = db_free_watchpoints) != 0) {
  81             db_free_watchpoints = watch->link;
  82             return (watch);
  83         }
  84         if (db_next_free_watchpoint == &db_watch_table[NWATCHPOINTS]) {
  85             db_printf("All watchpoints used.\n");
  86             return (0);
  87         }
  88         watch = db_next_free_watchpoint;
  89         db_next_free_watchpoint++;
  90
  91         return (watch);
  92 }
  93
  94 void
  95 db_watchpoint_free(watch)
  96         db_watchpoint_t watch;
  97 {
  98         watch->link = db_free_watchpoints;
  99         db_free_watchpoints = watch;
 100 }
 101
 102 static void
 103 db_set_watchpoint(map, addr, size)
 104         vm_map_t        map;
 105         db_addr_t       addr;
 106         vm_size_t       size;
 107 {
 108         db_watchpoint_t watch;
 109
 110         if (map == NULL) {
 111             db_printf("No map.\n");
 112             return;
 113         }
 114
 115         /*
 116          *      Should we do anything fancy with overlapping regions?
 117          */
 118
 119         for (watch = db_watchpoint_list;
 120              watch != 0;
 121              watch = watch->link)
 122             if (db_map_equal(watch->map, map) &&
 123                 (watch->loaddr == addr) &&
 124                 (watch->hiaddr == addr+size)) {
 125                 db_printf("Already set.\n");
 126                 return;
 127             }
 128
 129         watch = db_watchpoint_alloc();
 130         if (watch == 0) {
 131             db_printf("Too many watchpoints.\n");
 132             return;
 133         }
 134
 135         watch->map = map;
 136         watch->loaddr = addr;
 137         watch->hiaddr = addr+size;
 138
 139         watch->link = db_watchpoint_list;
 140         db_watchpoint_list = watch;
 141
 142         db_watchpoints_inserted = FALSE;
 143 }
 144
 145 static void
 146 db_delete_watchpoint(map, addr)
 147         vm_map_t        map;
 148         db_addr_t       addr;
 149 {
 150         db_watchpoint_t watch;
 151         db_watchpoint_t *prev;
 152
 153         for (prev = &db_watchpoint_list;
 154              (watch = *prev) != 0;
 155              prev = &watch->link)
 156             if (db_map_equal(watch->map, map) &&
 157                 (watch->loaddr <= addr) &&
 158                 (addr < watch->hiaddr)) {
 159                 *prev = watch->link;
 160                 db_watchpoint_free(watch);
 161                 return;
 162             }
 163
 164         db_printf("Not set.\n");
 165 }
 166
 167 static void
 168 db_list_watchpoints()
 169 {
 170         db_watchpoint_t watch;
 171
 172         if (db_watchpoint_list == 0) {
 173             db_printf("No watchpoints set\n");
 174             return;
 175         }
 176
 177         db_printf(" Map        Address  Size\n");
 178         for (watch = db_watchpoint_list;
 179              watch != 0;
 180              watch = watch->link)
 181             db_printf("%s%8p  %8lx  %lx\n",
 182                       db_map_current(watch->map) ? "*" : " ",
 183                       (void *)watch->map, (long)watch->loaddr,
 184                       (long)watch->hiaddr - (long)watch->loaddr);
 185 }
 186
 187 /* Delete watchpoint */
 188 /*ARGSUSED*/
 189 void
 190 db_deletewatch_cmd(addr, have_addr, count, modif)
 191         db_expr_t       addr;
 192         boolean_t       have_addr;
 193         db_expr_t       count;
 194         char *          modif;
 195 {
 196         db_delete_watchpoint(db_map_addr(addr), addr);
 197 }
 198
 199 /* Set watchpoint */
 200 /*ARGSUSED*/
 201 void
 202 db_watchpoint_cmd(addr, have_addr, count, modif)
 203         db_expr_t       addr;
 204         boolean_t       have_addr;
 205         db_expr_t       count;
 206         char *          modif;
 207 {
 208         vm_size_t       size;
 209         db_expr_t       value;
 210
 211         if (db_expression(&value))
 212             size = (vm_size_t) value;
 213         else
 214             size = 4;
 215         db_skip_to_eol();
 216
 217         db_set_watchpoint(db_map_addr(addr), addr, size);
 218 }
 219
 220 /*
 221  * At least one non-optional show-command must be implemented using
 222  * DB_SHOW_COMMAND() so that db_show_cmd_set gets created.  Here is one.
 223  */
 224 DB_SHOW_COMMAND(watches, db_listwatch_cmd)
 225 {
 226         db_list_watchpoints();
 227         db_md_list_watchpoints();
 228 }
 229
 230 void
 231 db_set_watchpoints()
 232 {
 233         db_watchpoint_t watch;
 234
 235         if (!db_watchpoints_inserted) {
 236             for (watch = db_watchpoint_list;
 237                  watch != 0;
 238                  watch = watch->link)
 239                 pmap_protect(watch->map->pmap,
 240                              trunc_page(watch->loaddr),
 241                              round_page(watch->hiaddr),
 242                              VM_PROT_READ);
 243
 244             db_watchpoints_inserted = TRUE;
 245         }
 246 }
 247
 248 void
 249 db_clear_watchpoints()
 250 {
 251         db_watchpoints_inserted = FALSE;
 252 }
 253
 254 #ifdef notused
 255 static boolean_t
 256 db_find_watchpoint(map, addr, regs)
 257         vm_map_t        map;
 258         db_addr_t       addr;
 259         db_regs_t       *regs;
 260 {
 261         db_watchpoint_t watch;
 262         db_watchpoint_t found = 0;
 263
 264         for (watch = db_watchpoint_list;
 265              watch != 0;
 266              watch = watch->link)
 267             if (db_map_equal(watch->map, map)) {
 268                 if ((watch->loaddr <= addr) &&
 269                     (addr < watch->hiaddr))
 270                     return (TRUE);
 271                 else if ((trunc_page(watch->loaddr) <= addr) &&
 272                          (addr < round_page(watch->hiaddr)))
 273                     found = watch;
 274             }
 275
 276         /*
 277          *      We didn't hit exactly on a watchpoint, but we are
 278          *      in a protected region.  We want to single-step
 279          *      and then re-protect.
 280          */
 281
 282         if (found) {
 283             db_watchpoints_inserted = FALSE;
 284             db_single_step(regs);
 285         }
 286
 287         return (FALSE);
 288 }
 289 #endif
 290
 291
 292
 293 /* Delete hardware watchpoint */
 294 /*ARGSUSED*/
 295 void
 296 db_deletehwatch_cmd(addr, have_addr, count, modif)
 297         db_expr_t       addr;
 298         boolean_t       have_addr;
 299         db_expr_t       count;
 300         char *          modif;
 301 {
 302         int rc;
 303
 304         if (count < 0)
 305                 count = 4;
 306
 307         rc = db_md_clr_watchpoint(addr, count);
 308         if (rc < 0)
 309                 db_printf("hardware watchpoint could not be deleted\n");
 310 }
 311
 312 /* Set hardware watchpoint */
 313 /*ARGSUSED*/
 314 void
 315 db_hwatchpoint_cmd(addr, have_addr, count, modif)
 316         db_expr_t       addr;
 317         boolean_t       have_addr;
 318         db_expr_t       count;
 319         char *          modif;
 320 {
 321         int rc;
 322
 323         if (count < 0)
 324                 count = 4;
 325
 326         rc = db_md_set_watchpoint(addr, count);
 327         if (rc < 0)
 328                 db_printf("hardware watchpoint could not be set\n");
 329 }