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/kdb.h>
  38 #include <sys/kernel.h>
  39 #include <sys/lock.h>
  40 #include <sys/proc.h>
  41
  42 #include <vm/vm.h>
  43 #include <vm/pmap.h>
  44 #include <vm/vm_map.h>
  45
  46 #include <machine/kdb.h>
  47
  48 #include <ddb/ddb.h>
  49 #include <ddb/db_watch.h>
  50
  51 /*
  52  * Watchpoints.
  53  */
  54
  55 static bool             db_watchpoints_inserted = true;
  56
  57 #define NWATCHPOINTS    100
  58 static struct db_watchpoint     db_watch_table[NWATCHPOINTS];
  59 static db_watchpoint_t  db_next_free_watchpoint = &db_watch_table[0];
  60 static db_watchpoint_t  db_free_watchpoints = 0;
  61 static db_watchpoint_t  db_watchpoint_list = 0;
  62
  63 static db_watchpoint_t  db_watchpoint_alloc(void);
  64 static void             db_watchpoint_free(db_watchpoint_t watch);
  65 static void             db_delete_watchpoint(vm_map_t map, db_addr_t addr);
  66 #ifdef notused
  67 static bool             db_find_watchpoint(vm_map_t map, db_addr_t addr,
  68                                         db_regs_t *regs);
  69 #endif
  70 static void             db_list_watchpoints(void);
  71 static void             db_set_watchpoint(vm_map_t map, db_addr_t addr,
  72                                        vm_size_t size);
  73
  74 static db_watchpoint_t
  75 db_watchpoint_alloc(void)
  76 {
  77         db_watchpoint_t watch;
  78
  79         if ((watch = db_free_watchpoints) != 0) {
  80             db_free_watchpoints = watch->link;
  81             return (watch);
  82         }
  83         if (db_next_free_watchpoint == &db_watch_table[NWATCHPOINTS]) {
  84             db_printf("All watchpoints used.\n");
  85             return (0);
  86         }
  87         watch = db_next_free_watchpoint;
  88         db_next_free_watchpoint++;
  89
  90         return (watch);
  91 }
  92
  93 static void
  94 db_watchpoint_free(db_watchpoint_t watch)
  95 {
  96         watch->link = db_free_watchpoints;
  97         db_free_watchpoints = watch;
  98 }
  99
 100 static void
 101 db_set_watchpoint(vm_map_t map, db_addr_t addr, vm_size_t size)
 102 {
 103         db_watchpoint_t watch;
 104
 105         if (map == NULL) {
 106             db_printf("No map.\n");
 107             return;
 108         }
 109
 110         /*
 111          *      Should we do anything fancy with overlapping regions?
 112          */
 113
 114         for (watch = db_watchpoint_list;
 115              watch != 0;
 116              watch = watch->link)
 117             if (db_map_equal(watch->map, map) &&
 118                 (watch->loaddr == addr) &&
 119                 (watch->hiaddr == addr+size)) {
 120                 db_printf("Already set.\n");
 121                 return;
 122             }
 123
 124         watch = db_watchpoint_alloc();
 125         if (watch == 0) {
 126             db_printf("Too many watchpoints.\n");
 127             return;
 128         }
 129
 130         watch->map = map;
 131         watch->loaddr = addr;
 132         watch->hiaddr = addr+size;
 133
 134         watch->link = db_watchpoint_list;
 135         db_watchpoint_list = watch;
 136
 137         db_watchpoints_inserted = false;
 138 }
 139
 140 static void
 141 db_delete_watchpoint(vm_map_t map, db_addr_t addr)
 142 {
 143         db_watchpoint_t watch;
 144         db_watchpoint_t *prev;
 145
 146         for (prev = &db_watchpoint_list;
 147              (watch = *prev) != 0;
 148              prev = &watch->link)
 149             if (db_map_equal(watch->map, map) &&
 150                 (watch->loaddr <= addr) &&
 151                 (addr < watch->hiaddr)) {
 152                 *prev = watch->link;
 153                 db_watchpoint_free(watch);
 154                 return;
 155             }
 156
 157         db_printf("Not set.\n");
 158 }
 159
 160 static void
 161 db_list_watchpoints(void)
 162 {
 163         db_watchpoint_t watch;
 164
 165         if (db_watchpoint_list == 0) {
 166             db_printf("No watchpoints set\n");
 167             return;
 168         }
 169
 170 #ifdef __LP64__
 171         db_printf(" Map                Address          Size\n");
 172 #else
 173         db_printf(" Map        Address  Size\n");
 174 #endif
 175         for (watch = db_watchpoint_list;
 176              watch != 0;
 177              watch = watch->link)
 178 #ifdef __LP64__
 179             db_printf("%s%16p  %16lx  %lx\n",
 180 #else
 181             db_printf("%s%8p  %8lx  %lx\n",
 182 #endif
 183                       db_map_current(watch->map) ? "*" : " ",
 184                       (void *)watch->map, (long)watch->loaddr,
 185                       (long)watch->hiaddr - (long)watch->loaddr);
 186 }
 187
 188 /* Delete watchpoint */
 189 /*ARGSUSED*/
 190 void
 191 db_deletewatch_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
 192    char *modif)
 193 {
 194         db_delete_watchpoint(db_map_addr(addr), addr);
 195 }
 196
 197 /* Set watchpoint */
 198 /*ARGSUSED*/
 199 void
 200 db_watchpoint_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
 201    char *modif)
 202 {
 203         vm_size_t       size;
 204         db_expr_t       value;
 205
 206         if (db_expression(&value))
 207             size = (vm_size_t) value;
 208         else
 209             size = 4;
 210         db_skip_to_eol();
 211
 212         db_set_watchpoint(db_map_addr(addr), addr, size);
 213 }
 214
 215 /*
 216  * At least one non-optional show-command must be implemented using
 217  * DB_SHOW_COMMAND() so that db_show_cmd_set gets created.  Here is one.
 218  */
 219 DB_SHOW_COMMAND_FLAGS(watches, db_listwatch_cmd, DB_CMD_MEMSAFE)
 220 {
 221         db_list_watchpoints();
 222         db_md_list_watchpoints();
 223 }
 224
 225 void
 226 db_set_watchpoints(void)
 227 {
 228         db_watchpoint_t watch;
 229
 230         if (!db_watchpoints_inserted) {
 231             for (watch = db_watchpoint_list;
 232                  watch != 0;
 233                  watch = watch->link)
 234                 pmap_protect(watch->map->pmap,
 235                              trunc_page(watch->loaddr),
 236                              round_page(watch->hiaddr),
 237                              VM_PROT_READ);
 238
 239             db_watchpoints_inserted = true;
 240         }
 241 }
 242
 243 void
 244 db_clear_watchpoints(void)
 245 {
 246         db_watchpoints_inserted = false;
 247 }
 248
 249 #ifdef notused
 250 static bool
 251 db_find_watchpoint(vm_map_t map, db_addr_t addr, db_regs_t regs)
 252 {
 253         db_watchpoint_t watch;
 254         db_watchpoint_t found = 0;
 255
 256         for (watch = db_watchpoint_list;
 257              watch != 0;
 258              watch = watch->link)
 259             if (db_map_equal(watch->map, map)) {
 260                 if ((watch->loaddr <= addr) &&
 261                     (addr < watch->hiaddr))
 262                     return (true);
 263                 else if ((trunc_page(watch->loaddr) <= addr) &&
 264                          (addr < round_page(watch->hiaddr)))
 265                     found = watch;
 266             }
 267
 268         /*
 269          *      We didn't hit exactly on a watchpoint, but we are
 270          *      in a protected region.  We want to single-step
 271          *      and then re-protect.
 272          */
 273
 274         if (found) {
 275             db_watchpoints_inserted = false;
 276             db_single_step(regs);
 277         }
 278
 279         return (false);
 280 }
 281 #endif
 282
 283 /* Delete hardware watchpoint */
 284 void
 285 db_deletehwatch_cmd(db_expr_t addr, bool have_addr, db_expr_t size,
 286    char *modif)
 287 {
 288         int rc;
 289
 290         if (size < 0)
 291                 size = 4;
 292
 293         rc = kdb_cpu_clr_watchpoint((vm_offset_t)addr, (vm_size_t)size);
 294         switch (rc) {
 295         case ENXIO:
 296                 /* Not supported, ignored. */
 297                 break;
 298         case EINVAL:
 299                 db_printf("Invalid watchpoint address or size.\n");
 300                 break;
 301         default:
 302                 if (rc != 0)
 303                         db_printf("Hardware watchpoint could not be deleted, "
 304                             "status=%d\n", rc);
 305                 break;
 306         }
 307 }
 308
 309 /* Set hardware watchpoint */
 310 void
 311 db_hwatchpoint_cmd(db_expr_t addr, bool have_addr, db_expr_t size,
 312    char *modif)
 313 {
 314         int rc;
 315
 316         if (size < 0)
 317                 size = 4;
 318
 319         rc = kdb_cpu_set_watchpoint((vm_offset_t)addr, (vm_size_t)size,
 320             KDB_DBG_ACCESS_W);
 321
 322         switch (rc) {
 323         case EINVAL:
 324                 db_printf("Invalid watchpoint size or address.\n");
 325                 break;
 326         case EBUSY:
 327                 db_printf("No hardware watchpoints available.\n");
 328                 break;
 329         case ENXIO:
 330                 db_printf("Hardware watchpoints are not supported on this platform.\n");
 331                 break;
 332         default:
 333                 if (rc != 0)
 334                         db_printf("Could not set hardware watchpoint, "
 335                             "status=%d\n", rc);
 336         }
 337 }