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  */
  28
  29 /*
  30  *      Author: David B. Golub, Carnegie Mellon University
  31  *      Date:   7/90
  32  */
  33
  34 /*
  35  * Commands to run process.
  36  */
  37 #include <sys/param.h>
  38
  39 #include <vm/vm.h>
  40
  41 #include <ddb/ddb.h>
  42 #include <ddb/db_break.h>
  43 #include <ddb/db_access.h>
  44
  45 static int      db_run_mode;
  46 #define STEP_NONE       0
  47 #define STEP_ONCE       1
  48 #define STEP_RETURN     2
  49 #define STEP_CALLT      3
  50 #define STEP_CONTINUE   4
  51 #define STEP_INVISIBLE  5
  52 #define STEP_COUNT      6
  53
  54 static boolean_t        db_sstep_print;
  55 static int              db_loop_count;
  56 static int              db_call_depth;
  57
  58 int             db_inst_count;
  59 int             db_load_count;
  60 int             db_store_count;
  61
  62 #ifndef db_set_single_step
  63 extern void     db_set_single_step (db_regs_t *regs);
  64 #endif
  65 #ifndef db_clear_single_step
  66 extern void     db_clear_single_step (db_regs_t *regs);
  67 #endif
  68
  69 #ifdef notused
  70 static void     db_single_step (db_regs_t *regs);
  71 #endif
  72
  73 boolean_t
  74 db_stop_at_pc(boolean_t *is_breakpoint)
  75 {
  76         db_addr_t       pc;
  77         db_breakpoint_t bkpt;
  78
  79         db_clear_single_step(DDB_REGS);
  80         db_clear_breakpoints();
  81         db_clear_watchpoints();
  82         pc = PC_REGS(DDB_REGS);
  83
  84 #ifdef  FIXUP_PC_AFTER_BREAK
  85         if (*is_breakpoint) {
  86             /*
  87              * Breakpoint trap.  Fix up the PC if the
  88              * machine requires it.
  89              */
  90             FIXUP_PC_AFTER_BREAK
  91             pc = PC_REGS(DDB_REGS);
  92         }
  93 #endif
  94
  95         /*
  96          * Now check for a breakpoint at this address.
  97          */
  98         bkpt = db_find_breakpoint_here(pc);
  99         if (bkpt) {
 100             if (--bkpt->count == 0) {
 101                 bkpt->count = bkpt->init_count;
 102                 *is_breakpoint = TRUE;
 103                 return (TRUE);  /* stop here */
 104             }
 105         } else if (*is_breakpoint) {
 106 #ifdef __x86_64__
 107                 ddb_regs.tf_rip += 1;
 108 #endif
 109         }
 110
 111         *is_breakpoint = FALSE;
 112
 113         if (db_run_mode == STEP_INVISIBLE) {
 114             db_run_mode = STEP_CONTINUE;
 115             return (FALSE);     /* continue */
 116         }
 117         if (db_run_mode == STEP_COUNT) {
 118             return (FALSE); /* continue */
 119         }
 120         if (db_run_mode == STEP_ONCE) {
 121             if (--db_loop_count > 0) {
 122                 if (db_sstep_print) {
 123                     db_printf("\t\t");
 124                     db_print_loc_and_inst(pc, DDB_REGS);
 125                     db_printf("\n");
 126                 }
 127                 return (FALSE); /* continue */
 128             }
 129         }
 130         if (db_run_mode == STEP_RETURN) {
 131             db_expr_t ins = db_get_value(pc, sizeof(int), FALSE);
 132
 133             /* continue until matching return */
 134
 135             if (!inst_trap_return(ins) &&
 136                 (!inst_return(ins) || --db_call_depth != 0)) {
 137                 if (db_sstep_print) {
 138                     if (inst_call(ins) || inst_return(ins)) {
 139                         int i;
 140
 141                         db_printf("[after %6d]     ", db_inst_count);
 142                         for (i = db_call_depth; --i > 0; )
 143                             db_printf("  ");
 144                         db_print_loc_and_inst(pc, DDB_REGS);
 145                         db_printf("\n");
 146                     }
 147                 }
 148                 if (inst_call(ins))
 149                     db_call_depth++;
 150                 return (FALSE); /* continue */
 151             }
 152         }
 153         if (db_run_mode == STEP_CALLT) {
 154             db_expr_t ins = db_get_value(pc, sizeof(int), FALSE);
 155
 156             /* continue until call or return */
 157
 158             if (!inst_call(ins) &&
 159                 !inst_return(ins) &&
 160                 !inst_trap_return(ins)) {
 161                 return (FALSE); /* continue */
 162             }
 163         }
 164         db_run_mode = STEP_NONE;
 165         return (TRUE);
 166 }
 167
 168 void
 169 db_restart_at_pc(boolean_t watchpt)
 170 {
 171         db_addr_t       pc = PC_REGS(DDB_REGS);
 172
 173         if ((db_run_mode == STEP_COUNT) ||
 174             (db_run_mode == STEP_RETURN) ||
 175             (db_run_mode == STEP_CALLT)) {
 176             db_expr_t   ins __unused;   /* seems used but gcc thinks not */
 177
 178             /*
 179              * We are about to execute this instruction,
 180              * so count it now.
 181              */
 182
 183             ins = db_get_value(pc, sizeof(int), FALSE);
 184             db_inst_count++;
 185             db_load_count += inst_load(ins);
 186             db_store_count += inst_store(ins);
 187 #ifdef  SOFTWARE_SSTEP
 188             /* XXX works on mips, but... */
 189             if (inst_branch(ins) || inst_call(ins)) {
 190                 ins = db_get_value(next_instr_address(pc,1),
 191                                    sizeof(int), FALSE);
 192                 db_inst_count++;
 193                 db_load_count += inst_load(ins);
 194                 db_store_count += inst_store(ins);
 195             }
 196 #endif  /* SOFTWARE_SSTEP */
 197         }
 198
 199         if (db_run_mode == STEP_CONTINUE) {
 200             if (watchpt || db_find_breakpoint_here(pc)) {
 201                 /*
 202                  * Step over breakpoint/watchpoint.
 203                  */
 204                 db_run_mode = STEP_INVISIBLE;
 205                 db_set_single_step(DDB_REGS);
 206             } else {
 207                 db_set_breakpoints();
 208                 db_set_watchpoints();
 209             }
 210         } else {
 211             db_set_single_step(DDB_REGS);
 212         }
 213 }
 214
 215 #ifdef notused
 216 static void
 217 db_single_step(db_regs_t *regs)
 218 {
 219         if (db_run_mode == STEP_CONTINUE) {
 220             db_run_mode = STEP_INVISIBLE;
 221             db_set_single_step(regs);
 222         }
 223 }
 224 #endif
 225
 226 #ifdef  SOFTWARE_SSTEP
 227 /*
 228  *      Software implementation of single-stepping.
 229  *      If your machine does not have a trace mode
 230  *      similar to the vax or sun ones you can use
 231  *      this implementation, done for the mips.
 232  *      Just define the above conditional and provide
 233  *      the functions/macros defined below.
 234  *
 235  * extern boolean_t
 236  *      inst_branch(),          returns true if the instruction might branch
 237  * extern unsigned
 238  *      branch_taken(),         return the address the instruction might
 239  *                              branch to
 240  *      db_getreg_val();        return the value of a user register,
 241  *                              as indicated in the hardware instruction
 242  *                              encoding, e.g. 8 for r8
 243  *
 244  * next_instr_address(pc,bd)    returns the address of the first
 245  *                              instruction following the one at "pc",
 246  *                              which is either in the taken path of
 247  *                              the branch (bd==1) or not.  This is
 248  *                              for machines (mips) with branch delays.
 249  *
 250  *      A single-step may involve at most 2 breakpoints -
 251  *      one for branch-not-taken and one for branch taken.
 252  *      If one of these addresses does not already have a breakpoint,
 253  *      we allocate a breakpoint and save it here.
 254  *      These breakpoints are deleted on return.
 255  */
 256 db_breakpoint_t db_not_taken_bkpt = 0;
 257 db_breakpoint_t db_taken_bkpt = 0;
 258
 259 void
 260 db_set_single_step(db_regs_t *regs)
 261 {
 262         db_addr_t pc = PC_REGS(regs), brpc;
 263          unsigned        inst;
 264
 265         /*
 266          *      User was stopped at pc, e.g. the instruction
 267          *      at pc was not executed.
 268          */
 269         inst = db_get_value(pc, sizeof(int), FALSE);
 270         if (inst_branch(inst) || inst_call(inst)) {
 271             brpc = branch_taken(inst, pc, regs);
 272             if (brpc != pc) {   /* self-branches are hopeless */
 273                 db_taken_bkpt = db_set_temp_breakpoint(brpc);
 274             }
 275             pc = next_instr_address(pc,1);
 276         }
 277         pc = next_instr_address(pc,0);
 278         db_not_taken_bkpt = db_set_temp_breakpoint(pc);
 279 }
 280
 281 void
 282 db_clear_single_step(db_regs_t *regs)
 283 {
 284
 285         if (db_not_taken_bkpt != 0) {
 286             db_delete_temp_breakpoint(db_not_taken_bkpt);
 287             db_not_taken_bkpt = 0;
 288         }
 289         if (db_taken_bkpt != 0) {
 290             db_delete_temp_breakpoint(db_taken_bkpt);
 291             db_taken_bkpt = 0;
 292         }
 293 }
 294
 295 #endif /* SOFTWARE_SSTEP */
 296
 297 extern boolean_t        db_cmd_loop_done;
 298
 299 /* single-step */
 300 /*ARGSUSED*/
 301 void
 302 db_single_step_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 303                    char *modif)
 304 {
 305         boolean_t       print = FALSE;
 306
 307         if (count == -1)
 308             count = 1;
 309
 310         if (modif[0] == 'p')
 311             print = TRUE;
 312
 313         db_run_mode = STEP_ONCE;
 314         db_loop_count = count;
 315         db_sstep_print = print;
 316         db_inst_count = 0;
 317         db_load_count = 0;
 318         db_store_count = 0;
 319
 320         db_cmd_loop_done = TRUE;
 321 }
 322
 323 /* trace and print until call/return */
 324 /*ARGSUSED*/
 325 void
 326 db_trace_until_call_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 327                         char *modif)
 328 {
 329         boolean_t       print = FALSE;
 330
 331         if (modif[0] == 'p')
 332             print = TRUE;
 333
 334         db_run_mode = STEP_CALLT;
 335         db_sstep_print = print;
 336         db_inst_count = 0;
 337         db_load_count = 0;
 338         db_store_count = 0;
 339
 340         db_cmd_loop_done = TRUE;
 341 }
 342
 343 /*ARGSUSED*/
 344 void
 345 db_trace_until_matching_cmd(db_expr_t addr, boolean_t have_addr,
 346                             db_expr_t count, char *modif)
 347 {
 348         boolean_t       print = FALSE;
 349
 350         if (modif[0] == 'p')
 351             print = TRUE;
 352
 353         db_run_mode = STEP_RETURN;
 354         db_call_depth = 1;
 355         db_sstep_print = print;
 356         db_inst_count = 0;
 357         db_load_count = 0;
 358         db_store_count = 0;
 359
 360         db_cmd_loop_done = TRUE;
 361 }
 362
 363 /* continue */
 364 /*ARGSUSED*/
 365 void
 366 db_continue_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 367                 char *modif)
 368 {
 369         if (modif[0] == 'c')
 370             db_run_mode = STEP_COUNT;
 371         else
 372             db_run_mode = STEP_CONTINUE;
 373         db_inst_count = 0;
 374         db_load_count = 0;
 375         db_store_count = 0;
 376
 377         db_cmd_loop_done = TRUE;
 378 }