sys/ddb/db_break.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 /*
  30  *      Author: David B. Golub, Carnegie Mellon University
  31  *      Date:   7/90
  32  */
  33 /*
  34  * Breakpoints.
  35  */
  36
  37 #include <sys/cdefs.h>
  38 __FBSDID("$FreeBSD$");
  39
  40 #include <sys/param.h>
  41
  42 #include <vm/vm.h>
  43 #include <vm/vm_kern.h>
  44
  45 #include <ddb/ddb.h>
  46 #include <ddb/db_break.h>
  47 #include <ddb/db_access.h>
  48 #include <ddb/db_sym.h>
  49
  50 #define NBREAKPOINTS    100
  51 static struct db_breakpoint     db_break_table[NBREAKPOINTS];
  52 static db_breakpoint_t          db_next_free_breakpoint = &db_break_table[0];
  53 static db_breakpoint_t          db_free_breakpoints = 0;
  54 static db_breakpoint_t          db_breakpoint_list = 0;
  55
  56 static db_breakpoint_t  db_breakpoint_alloc(void);
  57 static void     db_breakpoint_free(db_breakpoint_t bkpt);
  58 static void     db_delete_breakpoint(vm_map_t map, db_addr_t addr);
  59 static db_breakpoint_t  db_find_breakpoint(vm_map_t map, db_addr_t addr);
  60 static void     db_list_breakpoints(void);
  61 static void     db_set_breakpoint(vm_map_t map, db_addr_t addr, int count);
  62
  63 static db_breakpoint_t
  64 db_breakpoint_alloc(void)
  65 {
  66         register db_breakpoint_t        bkpt;
  67
  68         if ((bkpt = db_free_breakpoints) != 0) {
  69             db_free_breakpoints = bkpt->link;
  70             return (bkpt);
  71         }
  72         if (db_next_free_breakpoint == &db_break_table[NBREAKPOINTS]) {
  73             db_printf("All breakpoints used.\n");
  74             return (0);
  75         }
  76         bkpt = db_next_free_breakpoint;
  77         db_next_free_breakpoint++;
  78
  79         return (bkpt);
  80 }
  81
  82 static void
  83 db_breakpoint_free(db_breakpoint_t bkpt)
  84 {
  85         bkpt->link = db_free_breakpoints;
  86         db_free_breakpoints = bkpt;
  87 }
  88
  89 static void
  90 db_set_breakpoint(vm_map_t map, db_addr_t addr, int count)
  91 {
  92         register db_breakpoint_t        bkpt;
  93
  94         if (db_find_breakpoint(map, addr)) {
  95             db_printf("Already set.\n");
  96             return;
  97         }
  98
  99         bkpt = db_breakpoint_alloc();
 100         if (bkpt == 0) {
 101             db_printf("Too many breakpoints.\n");
 102             return;
 103         }
 104
 105         bkpt->map = map;
 106         bkpt->address = addr;
 107         bkpt->flags = 0;
 108         bkpt->init_count = count;
 109         bkpt->count = count;
 110
 111         bkpt->link = db_breakpoint_list;
 112         db_breakpoint_list = bkpt;
 113 }
 114
 115 static void
 116 db_delete_breakpoint(vm_map_t map, db_addr_t addr)
 117 {
 118         register db_breakpoint_t        bkpt;
 119         register db_breakpoint_t        *prev;
 120
 121         for (prev = &db_breakpoint_list;
 122              (bkpt = *prev) != 0;
 123              prev = &bkpt->link) {
 124             if (db_map_equal(bkpt->map, map) &&
 125                 (bkpt->address == addr)) {
 126                 *prev = bkpt->link;
 127                 break;
 128             }
 129         }
 130         if (bkpt == 0) {
 131             db_printf("Not set.\n");
 132             return;
 133         }
 134
 135         db_breakpoint_free(bkpt);
 136 }
 137
 138 static db_breakpoint_t
 139 db_find_breakpoint(vm_map_t map, db_addr_t addr)
 140 {
 141         register db_breakpoint_t        bkpt;
 142
 143         for (bkpt = db_breakpoint_list;
 144              bkpt != 0;
 145              bkpt = bkpt->link)
 146         {
 147             if (db_map_equal(bkpt->map, map) &&
 148                 (bkpt->address == addr))
 149                 return (bkpt);
 150         }
 151         return (0);
 152 }
 153
 154 db_breakpoint_t
 155 db_find_breakpoint_here(db_addr_t addr)
 156 {
 157         return db_find_breakpoint(db_map_addr(addr), addr);
 158 }
 159
 160 static bool     db_breakpoints_inserted = true;
 161
 162 #ifndef BKPT_WRITE
 163 #define BKPT_WRITE(addr, storage)                               \
 164 do {                                                            \
 165         *storage = db_get_value(addr, BKPT_SIZE, false);        \
 166         db_put_value(addr, BKPT_SIZE, BKPT_SET(*storage));      \
 167 } while (0)
 168 #endif
 169
 170 #ifndef BKPT_CLEAR
 171 #define BKPT_CLEAR(addr, storage) \
 172         db_put_value(addr, BKPT_SIZE, *storage)
 173 #endif
 174
 175 void
 176 db_set_breakpoints(void)
 177 {
 178         register db_breakpoint_t        bkpt;
 179
 180         if (!db_breakpoints_inserted) {
 181                 for (bkpt = db_breakpoint_list;
 182                      bkpt != 0;
 183                      bkpt = bkpt->link)
 184                         if (db_map_current(bkpt->map)) {
 185                                 BKPT_WRITE(bkpt->address, &bkpt->bkpt_inst);
 186                         }
 187                 db_breakpoints_inserted = true;
 188         }
 189 }
 190
 191 void
 192 db_clear_breakpoints(void)
 193 {
 194         register db_breakpoint_t        bkpt;
 195
 196         if (db_breakpoints_inserted) {
 197                 for (bkpt = db_breakpoint_list;
 198                      bkpt != 0;
 199                      bkpt = bkpt->link)
 200                         if (db_map_current(bkpt->map)) {
 201                                 BKPT_CLEAR(bkpt->address, &bkpt->bkpt_inst);
 202                         }
 203                 db_breakpoints_inserted = false;
 204         }
 205 }
 206
 207 #ifdef SOFTWARE_SSTEP
 208 /*
 209  * Set a temporary breakpoint.
 210  * The instruction is changed immediately,
 211  * so the breakpoint does not have to be on the breakpoint list.
 212  */
 213 db_breakpoint_t
 214 db_set_temp_breakpoint(db_addr_t addr)
 215 {
 216         register db_breakpoint_t        bkpt;
 217
 218         bkpt = db_breakpoint_alloc();
 219         if (bkpt == 0) {
 220             db_printf("Too many breakpoints.\n");
 221             return 0;
 222         }
 223
 224         bkpt->map = NULL;
 225         bkpt->address = addr;
 226         bkpt->flags = BKPT_TEMP;
 227         bkpt->init_count = 1;
 228         bkpt->count = 1;
 229
 230         BKPT_WRITE(bkpt->address, &bkpt->bkpt_inst);
 231         return bkpt;
 232 }
 233
 234 void
 235 db_delete_temp_breakpoint(db_breakpoint_t bkpt)
 236 {
 237         BKPT_CLEAR(bkpt->address, &bkpt->bkpt_inst);
 238         db_breakpoint_free(bkpt);
 239 }
 240 #endif /* SOFTWARE_SSTEP */
 241
 242 /*
 243  * List breakpoints.
 244  */
 245 static void
 246 db_list_breakpoints(void)
 247 {
 248         register db_breakpoint_t        bkpt;
 249
 250         if (db_breakpoint_list == 0) {
 251             db_printf("No breakpoints set\n");
 252             return;
 253         }
 254
 255         db_printf(" Map      Count    Address\n");
 256         for (bkpt = db_breakpoint_list;
 257              bkpt != 0;
 258              bkpt = bkpt->link) {
 259             db_printf("%s%8p %5d    ",
 260                       db_map_current(bkpt->map) ? "*" : " ",
 261                       (void *)bkpt->map, bkpt->init_count);
 262             db_printsym(bkpt->address, DB_STGY_PROC);
 263             db_printf("\n");
 264         }
 265 }
 266
 267 /* Delete breakpoint */
 268 /*ARGSUSED*/
 269 void
 270 db_delete_cmd(db_expr_t addr, bool have_addr, db_expr_t count, char *modif)
 271 {
 272         db_delete_breakpoint(db_map_addr(addr), (db_addr_t)addr);
 273 }
 274
 275 /* Set breakpoint with skip count */
 276 /*ARGSUSED*/
 277 void
 278 db_breakpoint_cmd(db_expr_t addr, bool have_addr, db_expr_t count, char *modif)
 279 {
 280         if (count == -1)
 281             count = 1;
 282
 283         db_set_breakpoint(db_map_addr(addr), (db_addr_t)addr, count);
 284 }
 285
 286 /* list breakpoints */
 287 void
 288 db_listbreak_cmd(db_expr_t dummy1, bool dummy2, db_expr_t dummy3, char *dummy4)
 289 {
 290         db_list_breakpoints();
 291 }
 292
 293 /*
 294  *      We want ddb to be usable before most of the kernel has been
 295  *      initialized.  In particular, current_thread() or kernel_map
 296  *      (or both) may be null.
 297  */
 298
 299 bool
 300 db_map_equal(vm_map_t map1, vm_map_t map2)
 301 {
 302         return ((map1 == map2) ||
 303                 ((map1 == NULL) && (map2 == kernel_map)) ||
 304                 ((map1 == kernel_map) && (map2 == NULL)));
 305 }
 306
 307 bool
 308 db_map_current(vm_map_t map)
 309 {
 310 #if 0
 311         thread_t        thread;
 312
 313         return ((map == NULL) ||
 314                 (map == kernel_map) ||
 315                 (((thread = current_thread()) != NULL) &&
 316                  (map == thread->task->map)));
 317 #else
 318         return (true);
 319 #endif
 320 }
 321
 322 vm_map_t
 323 db_map_addr(vm_offset_t addr)
 324 {
 325 #if 0
 326         thread_t        thread;
 327
 328         /*
 329          *      We want to return kernel_map for all
 330          *      non-user addresses, even when debugging
 331          *      kernel tasks with their own maps.
 332          */
 333
 334         if ((VM_MIN_ADDRESS <= addr) &&
 335             (addr < VM_MAX_ADDRESS) &&
 336             ((thread = current_thread()) != NULL))
 337             return thread->task->map;
 338         else
 339 #endif
 340             return kernel_map;
 341 }