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