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 /* 27 * Author: David B. Golub, Carnegie Mellon University 28 * Date: 7/90 29 */ 30 31 /* 32 * Commands to run process. 33 */ 34 35 #include <sys/cdefs.h> 36 __FBSDID("$FreeBSD$"); 37 38 #include <sys/param.h> 39 #include <sys/kdb.h> 40 #include <sys/proc.h> 41 42 #include <machine/kdb.h> 43 #include <machine/pcb.h> 44 45 #include <vm/vm.h> 46 47 #include <ddb/ddb.h> 48 #include <ddb/db_break.h> 49 #include <ddb/db_access.h> 50 51 static int db_run_mode; 52 #define STEP_NONE 0 53 #define STEP_ONCE 1 54 #define STEP_RETURN 2 55 #define STEP_CALLT 3 56 #define STEP_CONTINUE 4 57 #define STEP_INVISIBLE 5 58 #define STEP_COUNT 6 59 60 static boolean_t db_sstep_print; 61 static int db_loop_count; 62 static int db_call_depth; 63 64 int db_inst_count; 65 int db_load_count; 66 int db_store_count; 67 68 #ifndef db_set_single_step 69 void db_set_single_step(void); 70 #endif 71 #ifndef db_clear_single_step 72 void db_clear_single_step(void); 73 #endif 74 75 #ifdef SOFTWARE_SSTEP 76 db_breakpoint_t db_not_taken_bkpt = 0; 77 db_breakpoint_t db_taken_bkpt = 0; 78 #endif 79 80 boolean_t 81 db_stop_at_pc(boolean_t *is_breakpoint) 82 { 83 register db_addr_t pc; 84 register db_breakpoint_t bkpt; 85 86 pc = PC_REGS(); 87 #ifdef SOFTWARE_SSTEP 88 if ((db_not_taken_bkpt != 0 && pc == db_not_taken_bkpt->address) 89 || (db_taken_bkpt != 0 && pc == db_taken_bkpt->address)) 90 *is_breakpoint = FALSE; 91 #endif 92 93 db_clear_single_step(); 94 db_clear_breakpoints(); 95 db_clear_watchpoints(); 96 97 #ifdef FIXUP_PC_AFTER_BREAK 98 if (*is_breakpoint) { 99 /* 100 * Breakpoint trap. Fix up the PC if the 101 * machine requires it. 102 */ 103 FIXUP_PC_AFTER_BREAK 104 pc = PC_REGS(); 105 } 106 #endif 107 108 /* 109 * Now check for a breakpoint at this address. 110 */ 111 bkpt = db_find_breakpoint_here(pc); 112 if (bkpt) { 113 if (--bkpt->count == 0) { 114 bkpt->count = bkpt->init_count; 115 *is_breakpoint = TRUE; 116 return (TRUE); /* stop here */ 117 } 118 } else if (*is_breakpoint) { 119 #ifdef BKPT_SKIP 120 BKPT_SKIP; 121 #endif 122 } 123 124 *is_breakpoint = FALSE; 125 126 if (db_run_mode == STEP_INVISIBLE) { 127 db_run_mode = STEP_CONTINUE; 128 return (FALSE); /* continue */ 129 } 130 if (db_run_mode == STEP_COUNT) { 131 return (FALSE); /* continue */ 132 } 133 if (db_run_mode == STEP_ONCE) { 134 if (--db_loop_count > 0) { 135 if (db_sstep_print) { 136 db_printf("\t\t"); 137 db_print_loc_and_inst(pc); 138 db_printf("\n"); 139 } 140 return (FALSE); /* continue */ 141 } 142 } 143 if (db_run_mode == STEP_RETURN) { 144 /* continue until matching return */ 145 db_expr_t ins; 146 147 ins = db_get_value(pc, sizeof(int), FALSE); 148 if (!inst_trap_return(ins) && 149 (!inst_return(ins) || --db_call_depth != 0)) { 150 if (db_sstep_print) { 151 if (inst_call(ins) || inst_return(ins)) { 152 register int i; 153 154 db_printf("[after %6d] ", db_inst_count); 155 for (i = db_call_depth; --i > 0; ) 156 db_printf(" "); 157 db_print_loc_and_inst(pc); 158 db_printf("\n"); 159 } 160 } 161 if (inst_call(ins)) 162 db_call_depth++; 163 return (FALSE); /* continue */ 164 } 165 } 166 if (db_run_mode == STEP_CALLT) { 167 /* continue until call or return */ 168 db_expr_t ins; 169 170 ins = db_get_value(pc, sizeof(int), FALSE); 171 if (!inst_call(ins) && 172 !inst_return(ins) && 173 !inst_trap_return(ins)) { 174 return (FALSE); /* continue */ 175 } 176 } 177 db_run_mode = STEP_NONE; 178 return (TRUE); 179 } 180 181 void 182 db_restart_at_pc(boolean_t watchpt) 183 { 184 register db_addr_t pc = PC_REGS(); 185 186 if ((db_run_mode == STEP_COUNT) || 187 (db_run_mode == STEP_RETURN) || 188 (db_run_mode == STEP_CALLT)) { 189 /* 190 * We are about to execute this instruction, 191 * so count it now. 192 */ 193 #ifdef SOFTWARE_SSTEP 194 db_expr_t ins = 195 #endif 196 db_get_value(pc, sizeof(int), FALSE); 197 db_inst_count++; 198 db_load_count += inst_load(ins); 199 db_store_count += inst_store(ins); 200 #ifdef SOFTWARE_SSTEP 201 /* XXX works on mips, but... */ 202 if (inst_branch(ins) || inst_call(ins)) { 203 ins = db_get_value(next_instr_address(pc,1), 204 sizeof(int), FALSE); 205 db_inst_count++; 206 db_load_count += inst_load(ins); 207 db_store_count += inst_store(ins); 208 } 209 #endif /* SOFTWARE_SSTEP */ 210 } 211 212 if (db_run_mode == STEP_CONTINUE) { 213 if (watchpt || db_find_breakpoint_here(pc)) { 214 /* 215 * Step over breakpoint/watchpoint. 216 */ 217 db_run_mode = STEP_INVISIBLE; 218 db_set_single_step(); 219 } else { 220 db_set_breakpoints(); 221 db_set_watchpoints(); 222 } 223 } else { 224 db_set_single_step(); 225 } 226 } 227 228 #ifdef SOFTWARE_SSTEP 229 /* 230 * Software implementation of single-stepping. 231 * If your machine does not have a trace mode 232 * similar to the vax or sun ones you can use 233 * this implementation, done for the mips. 234 * Just define the above conditional and provide 235 * the functions/macros defined below. 236 * 237 * extern boolean_t 238 * inst_branch(), returns true if the instruction might branch 239 * extern unsigned 240 * branch_taken(), return the address the instruction might 241 * branch to 242 * db_getreg_val(); return the value of a user register, 243 * as indicated in the hardware instruction 244 * encoding, e.g. 8 for r8 245 * 246 * next_instr_address(pc,bd) returns the address of the first 247 * instruction following the one at "pc", 248 * which is either in the taken path of 249 * the branch (bd==1) or not. This is 250 * for machines (mips) with branch delays. 251 * 252 * A single-step may involve at most 2 breakpoints - 253 * one for branch-not-taken and one for branch taken. 254 * If one of these addresses does not already have a breakpoint, 255 * we allocate a breakpoint and save it here. 256 * These breakpoints are deleted on return. 257 */ 258 259 void 260 db_set_single_step(void) 261 { 262 db_addr_t pc = PC_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) || inst_return(inst)) { 271 brpc = branch_taken(inst, pc); 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(void) 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 int db_cmd_loop_done; 298 299 /* single-step */ 300 /*ARGSUSED*/ 301 void 302 db_single_step_cmd(addr, have_addr, count, modif) 303 db_expr_t addr; 304 boolean_t have_addr; 305 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 } 382