sys/ddb/db_watch.c

   1 /*-
   2  * SPDX-License-Identifier: MIT-CMU
   3  *
   4  * Mach Operating System
   5  * Copyright (c) 1991,1990 Carnegie Mellon University
   6  * All Rights Reserved.
   7  *
   8  * Permission to use, copy, modify and distribute this software and its
   9  * documentation is hereby granted, provided that both the copyright
  10  * notice and this permission notice appear in all copies of the
  11  * software, derivative works or modified versions, and any portions
  12  * thereof, and that both notices appear in supporting documentation.
  13  *
  14  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
  15  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  16  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  17  *
  18  * Carnegie Mellon requests users of this software to return to
  19  *
  20  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  21  *  School of Computer Science
  22  *  Carnegie Mellon University
  23  *  Pittsburgh PA 15213-3890
  24  *
  25  * any improvements or extensions that they make and grant Carnegie the
  26  * rights to redistribute these changes.
  27  */
  28 /*
  29  *      Author: Richard P. Draves, Carnegie Mellon University
  30  *      Date:   10/90
  31  */
  32
  33 #include <sys/cdefs.h>
  34 __FBSDID("$FreeBSD$");
  35
  36 #include <sys/param.h>
  37 #include <sys/kernel.h>
  38 #include <sys/lock.h>
  39 #include <sys/proc.h>
  40
  41 #include <vm/vm.h>
  42 #include <vm/pmap.h>
  43 #include <vm/vm_map.h>
  44
  45 #include <ddb/ddb.h>
  46 #include <ddb/db_watch.h>
  47
  48 /*
  49  * Watchpoints.
  50  */
  51
  52 static bool             db_watchpoints_inserted = true;
  53
  54 #define NWATCHPOINTS    100
  55 static struct db_watchpoint     db_watch_table[NWATCHPOINTS];
  56 static db_watchpoint_t  db_next_free_watchpoint = &db_watch_table[0];
  57 static db_watchpoint_t  db_free_watchpoints = 0;
  58 static db_watchpoint_t  db_watchpoint_list = 0;
  59
  60 static db_watchpoint_t  db_watchpoint_alloc(void);
  61 static void             db_watchpoint_free(db_watchpoint_t watch);
  62 static void             db_delete_watchpoint(vm_map_t map, db_addr_t addr);
  63 #ifdef notused
  64 static bool             db_find_watchpoint(vm_map_t map, db_addr_t addr,
  65                                         db_regs_t *regs);
  66 #endif
  67 static void             db_list_watchpoints(void);
  68 static void             db_set_watchpoint(vm_map_t map, db_addr_t addr,
  69                                        vm_size_t size);
  70
  71 static db_watchpoint_t
  72 db_watchpoint_alloc(void)
  73 {
  74         db_watchpoint_t watch;
  75
  76         if ((watch = db_free_watchpoints) != 0) {
  77             db_free_watchpoints = watch->link;
  78             return (watch);
  79         }
  80         if (db_next_free_watchpoint == &db_watch_table[NWATCHPOINTS]) {
  81             db_printf("All watchpoints used.\n");
  82             return (0);
  83         }
  84         watch = db_next_free_watchpoint;
  85         db_next_free_watchpoint++;
  86
  87         return (watch);
  88 }
  89
  90 static void
  91 db_watchpoint_free(db_watchpoint_t watch)
  92 {
  93         watch->link = db_free_watchpoints;
  94         db_free_watchpoints = watch;
  95 }
  96
  97 static void
  98 db_set_watchpoint(vm_map_t map, db_addr_t addr, vm_size_t size)
  99 {
 100         db_watchpoint_t watch;
 101
 102         if (map == NULL) {
 103             db_printf("No map.\n");
 104             return;
 105         }
 106
 107         /*
 108          *      Should we do anything fancy with overlapping regions?
 109          */
 110
 111         for (watch = db_watchpoint_list;
 112              watch != 0;
 113              watch = watch->link)
 114             if (db_map_equal(watch->map, map) &&
 115                 (watch->loaddr == addr) &&
 116                 (watch->hiaddr == addr+size)) {
 117                 db_printf("Already set.\n");
 118                 return;
 119             }
 120
 121         watch = db_watchpoint_alloc();
 122         if (watch == 0) {
 123             db_printf("Too many watchpoints.\n");
 124             return;
 125         }
 126
 127         watch->map = map;
 128         watch->loaddr = addr;
 129         watch->hiaddr = addr+size;
 130
 131         watch->link = db_watchpoint_list;
 132         db_watchpoint_list = watch;
 133
 134         db_watchpoints_inserted = false;
 135 }
 136
 137 static void
 138 db_delete_watchpoint(vm_map_t map, db_addr_t addr)
 139 {
 140         db_watchpoint_t watch;
 141         db_watchpoint_t *prev;
 142
 143         for (prev = &db_watchpoint_list;
 144              (watch = *prev) != 0;
 145              prev = &watch->link)
 146             if (db_map_equal(watch->map, map) &&
 147                 (watch->loaddr <= addr) &&
 148                 (addr < watch->hiaddr)) {
 149                 *prev = watch->link;
 150                 db_watchpoint_free(watch);
 151                 return;
 152             }
 153
 154         db_printf("Not set.\n");
 155 }
 156
 157 static void
 158 db_list_watchpoints(void)
 159 {
 160         db_watchpoint_t watch;
 161
 162         if (db_watchpoint_list == 0) {
 163             db_printf("No watchpoints set\n");
 164             return;
 165         }
 166
 167 #ifdef __LP64__
 168         db_printf(" Map                Address          Size\n");
 169 #else
 170         db_printf(" Map        Address  Size\n");
 171 #endif
 172         for (watch = db_watchpoint_list;
 173              watch != 0;
 174              watch = watch->link)
 175 #ifdef __LP64__
 176             db_printf("%s%16p  %16lx  %lx\n",
 177 #else
 178             db_printf("%s%8p  %8lx  %lx\n",
 179 #endif
 180                       db_map_current(watch->map) ? "*" : " ",
 181                       (void *)watch->map, (long)watch->loaddr,
 182                       (long)watch->hiaddr - (long)watch->loaddr);
 183 }
 184
 185 /* Delete watchpoint */
 186 /*ARGSUSED*/
 187 void
 188 db_deletewatch_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
 189    char *modif)
 190 {
 191         db_delete_watchpoint(db_map_addr(addr), addr);
 192 }
 193
 194 /* Set watchpoint */
 195 /*ARGSUSED*/
 196 void
 197 db_watchpoint_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
 198    char *modif)
 199 {
 200         vm_size_t       size;
 201         db_expr_t       value;
 202
 203         if (db_expression(&value))
 204             size = (vm_size_t) value;
 205         else
 206             size = 4;
 207         db_skip_to_eol();
 208
 209         db_set_watchpoint(db_map_addr(addr), addr, size);
 210 }
 211
 212 /*
 213  * At least one non-optional show-command must be implemented using
 214  * DB_SHOW_COMMAND() so that db_show_cmd_set gets created.  Here is one.
 215  */
 216 DB_SHOW_COMMAND(watches, db_listwatch_cmd)
 217 {
 218         db_list_watchpoints();
 219         db_md_list_watchpoints();
 220 }
 221
 222 void
 223 db_set_watchpoints(void)
 224 {
 225         db_watchpoint_t watch;
 226
 227         if (!db_watchpoints_inserted) {
 228             for (watch = db_watchpoint_list;
 229                  watch != 0;
 230                  watch = watch->link)
 231                 pmap_protect(watch->map->pmap,
 232                              trunc_page(watch->loaddr),
 233                              round_page(watch->hiaddr),
 234                              VM_PROT_READ);
 235
 236             db_watchpoints_inserted = true;
 237         }
 238 }
 239
 240 void
 241 db_clear_watchpoints(void)
 242 {
 243         db_watchpoints_inserted = false;
 244 }
 245
 246 #ifdef notused
 247 static bool
 248 db_find_watchpoint(vm_map_t map, db_addr_t addr, db_regs_t regs)
 249 {
 250         db_watchpoint_t watch;
 251         db_watchpoint_t found = 0;
 252
 253         for (watch = db_watchpoint_list;
 254              watch != 0;
 255              watch = watch->link)
 256             if (db_map_equal(watch->map, map)) {
 257                 if ((watch->loaddr <= addr) &&
 258                     (addr < watch->hiaddr))
 259                     return (true);
 260                 else if ((trunc_page(watch->loaddr) <= addr) &&
 261                          (addr < round_page(watch->hiaddr)))
 262                     found = watch;
 263             }
 264
 265         /*
 266          *      We didn't hit exactly on a watchpoint, but we are
 267          *      in a protected region.  We want to single-step
 268          *      and then re-protect.
 269          */
 270
 271         if (found) {
 272             db_watchpoints_inserted = false;
 273             db_single_step(regs);
 274         }
 275
 276         return (false);
 277 }
 278 #endif
 279
 280 /* Delete hardware watchpoint */
 281 /*ARGSUSED*/
 282 void
 283 db_deletehwatch_cmd(db_expr_t addr, bool 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, bool 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 }