sys/ddb/db_run.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  * $FreeBSD: src/sys/ddb/db_run.c,v 1.18 1999/08/28 00:41:10 peter Exp $
  27  * $DragonFly: src/sys/ddb/db_run.c,v 1.7 2005/12/23 21:35:44 swildner Exp $
  28  */
  29
  30 /*
  31  *      Author: David B. Golub, Carnegie Mellon University
  32  *      Date:   7/90
  33  */
  34
  35 /*
  36  * Commands to run process.
  37  */
  38 #include <sys/param.h>
  39
  40 #include <vm/vm.h>
  41
  42 #include <ddb/ddb.h>
  43 #include <ddb/db_break.h>
  44 #include <ddb/db_access.h>
  45
  46 static int      db_run_mode;
  47 #define STEP_NONE       0
  48 #define STEP_ONCE       1
  49 #define STEP_RETURN     2
  50 #define STEP_CALLT      3
  51 #define STEP_CONTINUE   4
  52 #define STEP_INVISIBLE  5
  53 #define STEP_COUNT      6
  54
  55 static boolean_t        db_sstep_print;
  56 static int              db_loop_count;
  57 static int              db_call_depth;
  58
  59 int             db_inst_count;
  60 int             db_load_count;
  61 int             db_store_count;
  62
  63 #ifndef db_set_single_step
  64 extern void     db_set_single_step (db_regs_t *regs);
  65 #endif
  66 #ifndef db_clear_single_step
  67 extern void     db_clear_single_step (db_regs_t *regs);
  68 #endif
  69
  70 #ifdef notused
  71 static void     db_single_step (db_regs_t *regs);
  72 #endif
  73
  74 boolean_t
  75 db_stop_at_pc(boolean_t *is_breakpoint)
  76 {
  77         db_addr_t       pc;
  78         db_breakpoint_t bkpt;
  79
  80         db_clear_single_step(DDB_REGS);
  81         db_clear_breakpoints();
  82         db_clear_watchpoints();
  83         pc = PC_REGS(DDB_REGS);
  84
  85 #ifdef  FIXUP_PC_AFTER_BREAK
  86         if (*is_breakpoint) {
  87             /*
  88              * Breakpoint trap.  Fix up the PC if the
  89              * machine requires it.
  90              */
  91             FIXUP_PC_AFTER_BREAK
  92             pc = PC_REGS(DDB_REGS);
  93         }
  94 #endif
  95
  96         /*
  97          * Now check for a breakpoint at this address.
  98          */
  99         bkpt = db_find_breakpoint_here(pc);
 100         if (bkpt) {
 101             if (--bkpt->count == 0) {
 102                 bkpt->count = bkpt->init_count;
 103                 *is_breakpoint = TRUE;
 104                 return (TRUE);  /* stop here */
 105             }
 106         } else if (*is_breakpoint) {
 107 #ifdef __i386__                 /* XXx */
 108                 ddb_regs.tf_eip += 1;
 109 #endif
 110         }
 111
 112         *is_breakpoint = FALSE;
 113
 114         if (db_run_mode == STEP_INVISIBLE) {
 115             db_run_mode = STEP_CONTINUE;
 116             return (FALSE);     /* continue */
 117         }
 118         if (db_run_mode == STEP_COUNT) {
 119             return (FALSE); /* continue */
 120         }
 121         if (db_run_mode == STEP_ONCE) {
 122             if (--db_loop_count > 0) {
 123                 if (db_sstep_print) {
 124                     db_printf("\t\t");
 125                     db_print_loc_and_inst(pc, DDB_REGS);
 126                     db_printf("\n");
 127                 }
 128                 return (FALSE); /* continue */
 129             }
 130         }
 131         if (db_run_mode == STEP_RETURN) {
 132             db_expr_t ins = db_get_value(pc, sizeof(int), FALSE);
 133
 134             /* continue until matching return */
 135
 136             if (!inst_trap_return(ins) &&
 137                 (!inst_return(ins) || --db_call_depth != 0)) {
 138                 if (db_sstep_print) {
 139                     if (inst_call(ins) || inst_return(ins)) {
 140                         int i;
 141
 142                         db_printf("[after %6d]     ", db_inst_count);
 143                         for (i = db_call_depth; --i > 0; )
 144                             db_printf("  ");
 145                         db_print_loc_and_inst(pc, DDB_REGS);
 146                         db_printf("\n");
 147                     }
 148                 }
 149                 if (inst_call(ins))
 150                     db_call_depth++;
 151                 return (FALSE); /* continue */
 152             }
 153         }
 154         if (db_run_mode == STEP_CALLT) {
 155             db_expr_t ins = db_get_value(pc, sizeof(int), FALSE);
 156
 157             /* continue until call or return */
 158
 159             if (!inst_call(ins) &&
 160                 !inst_return(ins) &&
 161                 !inst_trap_return(ins)) {
 162                 return (FALSE); /* continue */
 163             }
 164         }
 165         db_run_mode = STEP_NONE;
 166         return (TRUE);
 167 }
 168
 169 void
 170 db_restart_at_pc(boolean_t watchpt)
 171 {
 172         db_addr_t       pc = PC_REGS(DDB_REGS);
 173
 174         if ((db_run_mode == STEP_COUNT) ||
 175             (db_run_mode == STEP_RETURN) ||
 176             (db_run_mode == STEP_CALLT)) {
 177             db_expr_t           ins;
 178
 179             /*
 180              * We are about to execute this instruction,
 181              * so count it now.
 182              */
 183
 184             ins = db_get_value(pc, sizeof(int), FALSE);
 185             db_inst_count++;
 186             db_load_count += inst_load(ins);
 187             db_store_count += inst_store(ins);
 188 #ifdef  SOFTWARE_SSTEP
 189             /* XXX works on mips, but... */
 190             if (inst_branch(ins) || inst_call(ins)) {
 191                 ins = db_get_value(next_instr_address(pc,1),
 192                                    sizeof(int), FALSE);
 193                 db_inst_count++;
 194                 db_load_count += inst_load(ins);
 195                 db_store_count += inst_store(ins);
 196             }
 197 #endif  /* SOFTWARE_SSTEP */
 198         }
 199
 200         if (db_run_mode == STEP_CONTINUE) {
 201             if (watchpt || db_find_breakpoint_here(pc)) {
 202                 /*
 203                  * Step over breakpoint/watchpoint.
 204                  */
 205                 db_run_mode = STEP_INVISIBLE;
 206                 db_set_single_step(DDB_REGS);
 207             } else {
 208                 db_set_breakpoints();
 209                 db_set_watchpoints();
 210             }
 211         } else {
 212             db_set_single_step(DDB_REGS);
 213         }
 214 }
 215
 216 #ifdef notused
 217 static void
 218 db_single_step(db_regs_t *regs)
 219 {
 220         if (db_run_mode == STEP_CONTINUE) {
 221             db_run_mode = STEP_INVISIBLE;
 222             db_set_single_step(regs);
 223         }
 224 }
 225 #endif
 226
 227 #ifdef  SOFTWARE_SSTEP
 228 /*
 229  *      Software implementation of single-stepping.
 230  *      If your machine does not have a trace mode
 231  *      similar to the vax or sun ones you can use
 232  *      this implementation, done for the mips.
 233  *      Just define the above conditional and provide
 234  *      the functions/macros defined below.
 235  *
 236  * extern boolean_t
 237  *      inst_branch(),          returns true if the instruction might branch
 238  * extern unsigned
 239  *      branch_taken(),         return the address the instruction might
 240  *                              branch to
 241  *      db_getreg_val();        return the value of a user register,
 242  *                              as indicated in the hardware instruction
 243  *                              encoding, e.g. 8 for r8
 244  *
 245  * next_instr_address(pc,bd)    returns the address of the first
 246  *                              instruction following the one at "pc",
 247  *                              which is either in the taken path of
 248  *                              the branch (bd==1) or not.  This is
 249  *                              for machines (mips) with branch delays.
 250  *
 251  *      A single-step may involve at most 2 breakpoints -
 252  *      one for branch-not-taken and one for branch taken.
 253  *      If one of these addresses does not already have a breakpoint,
 254  *      we allocate a breakpoint and save it here.
 255  *      These breakpoints are deleted on return.
 256  */
 257 db_breakpoint_t db_not_taken_bkpt = 0;
 258 db_breakpoint_t db_taken_bkpt = 0;
 259
 260 void
 261 db_set_single_step(db_regs_t *regs)
 262 {
 263         db_addr_t pc = PC_REGS(regs), brpc;
 264          unsigned        inst;
 265
 266         /*
 267          *      User was stopped at pc, e.g. the instruction
 268          *      at pc was not executed.
 269          */
 270         inst = db_get_value(pc, sizeof(int), FALSE);
 271         if (inst_branch(inst) || inst_call(inst)) {
 272             brpc = branch_taken(inst, pc, regs);
 273             if (brpc != pc) {   /* self-branches are hopeless */
 274                 db_taken_bkpt = db_set_temp_breakpoint(brpc);
 275             }
 276             pc = next_instr_address(pc,1);
 277         }
 278         pc = next_instr_address(pc,0);
 279         db_not_taken_bkpt = db_set_temp_breakpoint(pc);
 280 }
 281
 282 void
 283 db_clear_single_step(db_regs_t *regs)
 284 {
 285
 286         if (db_not_taken_bkpt != 0) {
 287             db_delete_temp_breakpoint(db_not_taken_bkpt);
 288             db_not_taken_bkpt = 0;
 289         }
 290         if (db_taken_bkpt != 0) {
 291             db_delete_temp_breakpoint(db_taken_bkpt);
 292             db_taken_bkpt = 0;
 293         }
 294 }
 295
 296 #endif /* SOFTWARE_SSTEP */
 297
 298 extern int      db_cmd_loop_done;
 299
 300 /* single-step */
 301 /*ARGSUSED*/
 302 void
 303 db_single_step_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 304                    char *modif)
 305 {
 306         boolean_t       print = FALSE;
 307
 308         if (count == -1)
 309             count = 1;
 310
 311         if (modif[0] == 'p')
 312             print = TRUE;
 313
 314         db_run_mode = STEP_ONCE;
 315         db_loop_count = count;
 316         db_sstep_print = print;
 317         db_inst_count = 0;
 318         db_load_count = 0;
 319         db_store_count = 0;
 320
 321         db_cmd_loop_done = 1;
 322 }
 323
 324 /* trace and print until call/return */
 325 /*ARGSUSED*/
 326 void
 327 db_trace_until_call_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 328                         char *modif)
 329 {
 330         boolean_t       print = FALSE;
 331
 332         if (modif[0] == 'p')
 333             print = TRUE;
 334
 335         db_run_mode = STEP_CALLT;
 336         db_sstep_print = print;
 337         db_inst_count = 0;
 338         db_load_count = 0;
 339         db_store_count = 0;
 340
 341         db_cmd_loop_done = 1;
 342 }
 343
 344 /*ARGSUSED*/
 345 void
 346 db_trace_until_matching_cmd(db_expr_t addr, boolean_t have_addr,
 347                             db_expr_t count, char *modif)
 348 {
 349         boolean_t       print = FALSE;
 350
 351         if (modif[0] == 'p')
 352             print = TRUE;
 353
 354         db_run_mode = STEP_RETURN;
 355         db_call_depth = 1;
 356         db_sstep_print = print;
 357         db_inst_count = 0;
 358         db_load_count = 0;
 359         db_store_count = 0;
 360
 361         db_cmd_loop_done = 1;
 362 }
 363
 364 /* continue */
 365 /*ARGSUSED*/
 366 void
 367 db_continue_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 368                 char *modif)
 369 {
 370         if (modif[0] == 'c')
 371             db_run_mode = STEP_COUNT;
 372         else
 373             db_run_mode = STEP_CONTINUE;
 374         db_inst_count = 0;
 375         db_load_count = 0;
 376         db_store_count = 0;
 377
 378         db_cmd_loop_done = 1;
 379 }