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 1.8 2008/08/25 17:01:37 dillon 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 #elif defined(__amd64__)
 110                 ddb_regs.tf_rip += 1;
 111 #endif
 112         }
 113
 114         *is_breakpoint = FALSE;
 115
 116         if (db_run_mode == STEP_INVISIBLE) {
 117             db_run_mode = STEP_CONTINUE;
 118             return (FALSE);     /* continue */
 119         }
 120         if (db_run_mode == STEP_COUNT) {
 121             return (FALSE); /* continue */
 122         }
 123         if (db_run_mode == STEP_ONCE) {
 124             if (--db_loop_count > 0) {
 125                 if (db_sstep_print) {
 126                     db_printf("\t\t");
 127                     db_print_loc_and_inst(pc, DDB_REGS);
 128                     db_printf("\n");
 129                 }
 130                 return (FALSE); /* continue */
 131             }
 132         }
 133         if (db_run_mode == STEP_RETURN) {
 134             db_expr_t ins = db_get_value(pc, sizeof(int), FALSE);
 135
 136             /* continue until matching return */
 137
 138             if (!inst_trap_return(ins) &&
 139                 (!inst_return(ins) || --db_call_depth != 0)) {
 140                 if (db_sstep_print) {
 141                     if (inst_call(ins) || inst_return(ins)) {
 142                         int i;
 143
 144                         db_printf("[after %6d]     ", db_inst_count);
 145                         for (i = db_call_depth; --i > 0; )
 146                             db_printf("  ");
 147                         db_print_loc_and_inst(pc, DDB_REGS);
 148                         db_printf("\n");
 149                     }
 150                 }
 151                 if (inst_call(ins))
 152                     db_call_depth++;
 153                 return (FALSE); /* continue */
 154             }
 155         }
 156         if (db_run_mode == STEP_CALLT) {
 157             db_expr_t ins = db_get_value(pc, sizeof(int), FALSE);
 158
 159             /* continue until call or return */
 160
 161             if (!inst_call(ins) &&
 162                 !inst_return(ins) &&
 163                 !inst_trap_return(ins)) {
 164                 return (FALSE); /* continue */
 165             }
 166         }
 167         db_run_mode = STEP_NONE;
 168         return (TRUE);
 169 }
 170
 171 void
 172 db_restart_at_pc(boolean_t watchpt)
 173 {
 174         db_addr_t       pc = PC_REGS(DDB_REGS);
 175
 176         if ((db_run_mode == STEP_COUNT) ||
 177             (db_run_mode == STEP_RETURN) ||
 178             (db_run_mode == STEP_CALLT)) {
 179             db_expr_t           ins;
 180
 181             /*
 182              * We are about to execute this instruction,
 183              * so count it now.
 184              */
 185
 186             ins = db_get_value(pc, sizeof(int), FALSE);
 187             db_inst_count++;
 188             db_load_count += inst_load(ins);
 189             db_store_count += inst_store(ins);
 190 #ifdef  SOFTWARE_SSTEP
 191             /* XXX works on mips, but... */
 192             if (inst_branch(ins) || inst_call(ins)) {
 193                 ins = db_get_value(next_instr_address(pc,1),
 194                                    sizeof(int), FALSE);
 195                 db_inst_count++;
 196                 db_load_count += inst_load(ins);
 197                 db_store_count += inst_store(ins);
 198             }
 199 #endif  /* SOFTWARE_SSTEP */
 200         }
 201
 202         if (db_run_mode == STEP_CONTINUE) {
 203             if (watchpt || db_find_breakpoint_here(pc)) {
 204                 /*
 205                  * Step over breakpoint/watchpoint.
 206                  */
 207                 db_run_mode = STEP_INVISIBLE;
 208                 db_set_single_step(DDB_REGS);
 209             } else {
 210                 db_set_breakpoints();
 211                 db_set_watchpoints();
 212             }
 213         } else {
 214             db_set_single_step(DDB_REGS);
 215         }
 216 }
 217
 218 #ifdef notused
 219 static void
 220 db_single_step(db_regs_t *regs)
 221 {
 222         if (db_run_mode == STEP_CONTINUE) {
 223             db_run_mode = STEP_INVISIBLE;
 224             db_set_single_step(regs);
 225         }
 226 }
 227 #endif
 228
 229 #ifdef  SOFTWARE_SSTEP
 230 /*
 231  *      Software implementation of single-stepping.
 232  *      If your machine does not have a trace mode
 233  *      similar to the vax or sun ones you can use
 234  *      this implementation, done for the mips.
 235  *      Just define the above conditional and provide
 236  *      the functions/macros defined below.
 237  *
 238  * extern boolean_t
 239  *      inst_branch(),          returns true if the instruction might branch
 240  * extern unsigned
 241  *      branch_taken(),         return the address the instruction might
 242  *                              branch to
 243  *      db_getreg_val();        return the value of a user register,
 244  *                              as indicated in the hardware instruction
 245  *                              encoding, e.g. 8 for r8
 246  *
 247  * next_instr_address(pc,bd)    returns the address of the first
 248  *                              instruction following the one at "pc",
 249  *                              which is either in the taken path of
 250  *                              the branch (bd==1) or not.  This is
 251  *                              for machines (mips) with branch delays.
 252  *
 253  *      A single-step may involve at most 2 breakpoints -
 254  *      one for branch-not-taken and one for branch taken.
 255  *      If one of these addresses does not already have a breakpoint,
 256  *      we allocate a breakpoint and save it here.
 257  *      These breakpoints are deleted on return.
 258  */
 259 db_breakpoint_t db_not_taken_bkpt = 0;
 260 db_breakpoint_t db_taken_bkpt = 0;
 261
 262 void
 263 db_set_single_step(db_regs_t *regs)
 264 {
 265         db_addr_t pc = PC_REGS(regs), brpc;
 266          unsigned        inst;
 267
 268         /*
 269          *      User was stopped at pc, e.g. the instruction
 270          *      at pc was not executed.
 271          */
 272         inst = db_get_value(pc, sizeof(int), FALSE);
 273         if (inst_branch(inst) || inst_call(inst)) {
 274             brpc = branch_taken(inst, pc, regs);
 275             if (brpc != pc) {   /* self-branches are hopeless */
 276                 db_taken_bkpt = db_set_temp_breakpoint(brpc);
 277             }
 278             pc = next_instr_address(pc,1);
 279         }
 280         pc = next_instr_address(pc,0);
 281         db_not_taken_bkpt = db_set_temp_breakpoint(pc);
 282 }
 283
 284 void
 285 db_clear_single_step(db_regs_t *regs)
 286 {
 287
 288         if (db_not_taken_bkpt != 0) {
 289             db_delete_temp_breakpoint(db_not_taken_bkpt);
 290             db_not_taken_bkpt = 0;
 291         }
 292         if (db_taken_bkpt != 0) {
 293             db_delete_temp_breakpoint(db_taken_bkpt);
 294             db_taken_bkpt = 0;
 295         }
 296 }
 297
 298 #endif /* SOFTWARE_SSTEP */
 299
 300 extern int      db_cmd_loop_done;
 301
 302 /* single-step */
 303 /*ARGSUSED*/
 304 void
 305 db_single_step_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 306                    char *modif)
 307 {
 308         boolean_t       print = FALSE;
 309
 310         if (count == -1)
 311             count = 1;
 312
 313         if (modif[0] == 'p')
 314             print = TRUE;
 315
 316         db_run_mode = STEP_ONCE;
 317         db_loop_count = count;
 318         db_sstep_print = print;
 319         db_inst_count = 0;
 320         db_load_count = 0;
 321         db_store_count = 0;
 322
 323         db_cmd_loop_done = 1;
 324 }
 325
 326 /* trace and print until call/return */
 327 /*ARGSUSED*/
 328 void
 329 db_trace_until_call_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 330                         char *modif)
 331 {
 332         boolean_t       print = FALSE;
 333
 334         if (modif[0] == 'p')
 335             print = TRUE;
 336
 337         db_run_mode = STEP_CALLT;
 338         db_sstep_print = print;
 339         db_inst_count = 0;
 340         db_load_count = 0;
 341         db_store_count = 0;
 342
 343         db_cmd_loop_done = 1;
 344 }
 345
 346 /*ARGSUSED*/
 347 void
 348 db_trace_until_matching_cmd(db_expr_t addr, boolean_t have_addr,
 349                             db_expr_t count, char *modif)
 350 {
 351         boolean_t       print = FALSE;
 352
 353         if (modif[0] == 'p')
 354             print = TRUE;
 355
 356         db_run_mode = STEP_RETURN;
 357         db_call_depth = 1;
 358         db_sstep_print = print;
 359         db_inst_count = 0;
 360         db_load_count = 0;
 361         db_store_count = 0;
 362
 363         db_cmd_loop_done = 1;
 364 }
 365
 366 /* continue */
 367 /*ARGSUSED*/
 368 void
 369 db_continue_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 370                 char *modif)
 371 {
 372         if (modif[0] == 'c')
 373             db_run_mode = STEP_COUNT;
 374         else
 375             db_run_mode = STEP_CONTINUE;
 376         db_inst_count = 0;
 377         db_load_count = 0;
 378         db_store_count = 0;
 379
 380         db_cmd_loop_done = 1;
 381 }