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 #ifdef __LP64__
 172         db_printf(" Map                Address          Size\n");
 173 #else
 174         db_printf(" Map        Address  Size\n");
 175 #endif
 176         for (watch = db_watchpoint_list;
 177              watch != 0;
 178              watch = watch->link)
 179 #ifdef __LP64__
 180             db_printf("%s%16p  %16lx  %lx\n",
 181 #else
 182             db_printf("%s%8p  %8lx  %lx\n",
 183 #endif
 184                       db_map_current(watch->map) ? "*" : " ",
 185                       (void *)watch->map, (long)watch->loaddr,
 186                       (long)watch->hiaddr - (long)watch->loaddr);
 187 }
 188
 189 /* Delete watchpoint */
 190 /*ARGSUSED*/
 191 void
 192 db_deletewatch_cmd(addr, have_addr, count, modif)
 193         db_expr_t       addr;
 194         boolean_t       have_addr;
 195         db_expr_t       count;
 196         char *          modif;
 197 {
 198         db_delete_watchpoint(db_map_addr(addr), addr);
 199 }
 200
 201 /* Set watchpoint */
 202 /*ARGSUSED*/
 203 void
 204 db_watchpoint_cmd(addr, have_addr, count, modif)
 205         db_expr_t       addr;
 206         boolean_t       have_addr;
 207         db_expr_t       count;
 208         char *          modif;
 209 {
 210         vm_size_t       size;
 211         db_expr_t       value;
 212
 213         if (db_expression(&value))
 214             size = (vm_size_t) value;
 215         else
 216             size = 4;
 217         db_skip_to_eol();
 218
 219         db_set_watchpoint(db_map_addr(addr), addr, size);
 220 }
 221
 222 /*
 223  * At least one non-optional show-command must be implemented using
 224  * DB_SHOW_COMMAND() so that db_show_cmd_set gets created.  Here is one.
 225  */
 226 DB_SHOW_COMMAND(watches, db_listwatch_cmd)
 227 {
 228         db_list_watchpoints();
 229         db_md_list_watchpoints();
 230 }
 231
 232 void
 233 db_set_watchpoints()
 234 {
 235         register db_watchpoint_t        watch;
 236
 237         if (!db_watchpoints_inserted) {
 238             for (watch = db_watchpoint_list;
 239                  watch != 0;
 240                  watch = watch->link)
 241                 pmap_protect(watch->map->pmap,
 242                              trunc_page(watch->loaddr),
 243                              round_page(watch->hiaddr),
 244                              VM_PROT_READ);
 245
 246             db_watchpoints_inserted = TRUE;
 247         }
 248 }
 249
 250 void
 251 db_clear_watchpoints()
 252 {
 253         db_watchpoints_inserted = FALSE;
 254 }
 255
 256 #ifdef notused
 257 static boolean_t
 258 db_find_watchpoint(map, addr, regs)
 259         vm_map_t        map;
 260         db_addr_t       addr;
 261         db_regs_t       *regs;
 262 {
 263         register db_watchpoint_t watch;
 264         db_watchpoint_t found = 0;
 265
 266         for (watch = db_watchpoint_list;
 267              watch != 0;
 268              watch = watch->link)
 269             if (db_map_equal(watch->map, map)) {
 270                 if ((watch->loaddr <= addr) &&
 271                     (addr < watch->hiaddr))
 272                     return (TRUE);
 273                 else if ((trunc_page(watch->loaddr) <= addr) &&
 274                          (addr < round_page(watch->hiaddr)))
 275                     found = watch;
 276             }
 277
 278         /*
 279          *      We didn't hit exactly on a watchpoint, but we are
 280          *      in a protected region.  We want to single-step
 281          *      and then re-protect.
 282          */
 283
 284         if (found) {
 285             db_watchpoints_inserted = FALSE;
 286             db_single_step(regs);
 287         }
 288
 289         return (FALSE);
 290 }
 291 #endif
 292
 293
 294
 295 /* Delete hardware watchpoint */
 296 /*ARGSUSED*/
 297 void
 298 db_deletehwatch_cmd(addr, have_addr, count, modif)
 299         db_expr_t       addr;
 300         boolean_t       have_addr;
 301         db_expr_t       count;
 302         char *          modif;
 303 {
 304         int rc;
 305
 306         if (count < 0)
 307                 count = 4;
 308
 309         rc = db_md_clr_watchpoint(addr, count);
 310         if (rc < 0)
 311                 db_printf("hardware watchpoint could not be deleted\n");
 312 }
 313
 314 /* Set hardware watchpoint */
 315 /*ARGSUSED*/
 316 void
 317 db_hwatchpoint_cmd(addr, have_addr, count, modif)
 318         db_expr_t       addr;
 319         boolean_t       have_addr;
 320         db_expr_t       count;
 321         char *          modif;
 322 {
 323         int rc;
 324
 325         if (count < 0)
 326                 count = 4;
 327
 328         rc = db_md_set_watchpoint(addr, count);
 329         if (rc < 0)
 330                 db_printf("hardware watchpoint could not be set\n");
 331 }