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 1.5 2005/12/23 21:35:44 swildner 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(void)
  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(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(vm_map_t map, db_addr_t addr, vm_size_t size)
 103 {
 104         db_watchpoint_t watch;
 105
 106         if (map == NULL) {
 107             db_printf("No map.\n");
 108             return;
 109         }
 110
 111         /*
 112          *      Should we do anything fancy with overlapping regions?
 113          */
 114
 115         for (watch = db_watchpoint_list;
 116              watch != 0;
 117              watch = watch->link)
 118             if (db_map_equal(watch->map, map) &&
 119                 (watch->loaddr == addr) &&
 120                 (watch->hiaddr == addr+size)) {
 121                 db_printf("Already set.\n");
 122                 return;
 123             }
 124
 125         watch = db_watchpoint_alloc();
 126         if (watch == 0) {
 127             db_printf("Too many watchpoints.\n");
 128             return;
 129         }
 130
 131         watch->map = map;
 132         watch->loaddr = addr;
 133         watch->hiaddr = addr+size;
 134
 135         watch->link = db_watchpoint_list;
 136         db_watchpoint_list = watch;
 137
 138         db_watchpoints_inserted = FALSE;
 139 }
 140
 141 static void
 142 db_delete_watchpoint(vm_map_t map, db_addr_t addr)
 143 {
 144         db_watchpoint_t watch;
 145         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(void)
 163 {
 164         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(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 185                    char *modif)
 186 {
 187         db_delete_watchpoint(db_map_addr(addr), addr);
 188 }
 189
 190 /* Set watchpoint */
 191 /*ARGSUSED*/
 192 void
 193 db_watchpoint_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 194                   char *modif)
 195 {
 196         vm_size_t       size;
 197         db_expr_t       value;
 198
 199         if (db_expression(&value))
 200             size = (vm_size_t) value;
 201         else
 202             size = 4;
 203         db_skip_to_eol();
 204
 205         db_set_watchpoint(db_map_addr(addr), addr, size);
 206 }
 207
 208 /*
 209  * At least one non-optional show-command must be implemented using
 210  * DB_SHOW_COMMAND() so that db_show_cmd_set gets created.  Here is one.
 211  */
 212 DB_SHOW_COMMAND(watches, db_listwatch_cmd)
 213 {
 214         db_list_watchpoints();
 215         db_md_list_watchpoints();
 216 }
 217
 218 void
 219 db_set_watchpoints(void)
 220 {
 221         db_watchpoint_t watch;
 222
 223         if (!db_watchpoints_inserted) {
 224             for (watch = db_watchpoint_list;
 225                  watch != 0;
 226                  watch = watch->link)
 227                 pmap_protect(watch->map->pmap,
 228                              trunc_page(watch->loaddr),
 229                              round_page(watch->hiaddr),
 230                              VM_PROT_READ);
 231
 232             db_watchpoints_inserted = TRUE;
 233         }
 234 }
 235
 236 void
 237 db_clear_watchpoints(void)
 238 {
 239         db_watchpoints_inserted = FALSE;
 240 }
 241
 242 #ifdef notused
 243 static boolean_t
 244 db_find_watchpoint(vm_map_t map, db_addr_t addr, db_regs_t *regs)
 245 {
 246         db_watchpoint_t watch;
 247         db_watchpoint_t found = 0;
 248
 249         for (watch = db_watchpoint_list;
 250              watch != 0;
 251              watch = watch->link)
 252             if (db_map_equal(watch->map, map)) {
 253                 if ((watch->loaddr <= addr) &&
 254                     (addr < watch->hiaddr))
 255                     return (TRUE);
 256                 else if ((trunc_page(watch->loaddr) <= addr) &&
 257                          (addr < round_page(watch->hiaddr)))
 258                     found = watch;
 259             }
 260
 261         /*
 262          *      We didn't hit exactly on a watchpoint, but we are
 263          *      in a protected region.  We want to single-step
 264          *      and then re-protect.
 265          */
 266
 267         if (found) {
 268             db_watchpoints_inserted = FALSE;
 269             db_single_step(regs);
 270         }
 271
 272         return (FALSE);
 273 }
 274 #endif
 275
 276
 277
 278 /* Delete hardware watchpoint */
 279 /*ARGSUSED*/
 280 void
 281 db_deletehwatch_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 282                     char *modif)
 283 {
 284         int rc;
 285
 286         if (count < 0)
 287                 count = 4;
 288
 289         rc = db_md_clr_watchpoint(addr, count);
 290         if (rc < 0)
 291                 db_printf("hardware watchpoint could not be deleted\n");
 292 }
 293
 294 /* Set hardware watchpoint */
 295 /*ARGSUSED*/
 296 void
 297 db_hwatchpoint_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 298                    char *modif)
 299 {
 300         int rc;
 301
 302         if (count < 0)
 303                 count = 4;
 304
 305         rc = db_md_set_watchpoint(addr, count);
 306         if (rc < 0)
 307                 db_printf("hardware watchpoint could not be set\n");
 308 }