1 /* $NetBSD: db_run.c,v 1.33 2014/09/19 17:29:01 matt Exp $ */ 2 3 /* 4 * Mach Operating System 5 * Copyright (c) 1993-1990 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 "AS IS" 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 (at) 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 * Author: David B. Golub, Carnegie Mellon University 29 * Date: 7/90 30 */ 31 32 /* 33 * Commands to run process. 34 */ 35 36 #include <sys/cdefs.h> 37 __KERNEL_RCSID(0, "$NetBSD: db_run.c,v 1.33 2014/09/19 17:29:01 matt Exp $"); 38 39 #include "opt_ddb.h" 40 41 #include <sys/param.h> 42 #include <sys/proc.h> 43 44 #include <machine/db_machdep.h> 45 46 #include <ddb/db_run.h> 47 #include <ddb/db_access.h> 48 #include <ddb/db_break.h> 49 50 int db_inst_count; 51 int db_load_count; 52 int db_store_count; 53 54 #ifdef SOFTWARE_SSTEP 55 static void db_set_temp_breakpoint(db_breakpoint_t, db_addr_t); 56 static void db_delete_temp_breakpoint(db_breakpoint_t); 57 static struct db_breakpoint db_not_taken_bkpt; 58 static struct db_breakpoint db_taken_bkpt; 59 #endif 60 61 #if defined(DDB) 62 #include <ddb/db_lex.h> 63 #include <ddb/db_watch.h> 64 #include <ddb/db_output.h> 65 #include <ddb/db_sym.h> 66 #include <ddb/db_extern.h> 67 68 static int db_run_mode; 69 #define STEP_NONE 0 70 #define STEP_ONCE 1 71 #define STEP_RETURN 2 72 #define STEP_CALLT 3 73 #define STEP_CONTINUE 4 74 #define STEP_INVISIBLE 5 75 #define STEP_COUNT 6 76 77 static bool db_sstep_print; 78 static int db_loop_count; 79 static int db_call_depth; 80 81 bool 82 db_stop_at_pc(db_regs_t *regs, bool *is_breakpoint) 83 { 84 db_addr_t pc; 85 db_breakpoint_t bkpt; 86 87 pc = PC_REGS(regs); 88 89 #ifdef FIXUP_PC_AFTER_BREAK 90 if (*is_breakpoint) { 91 /* 92 * Breakpoint trap. Regardless if we treat this as a 93 * real breakpoint (e.g. software single-step), fix up the PC. 94 */ 95 FIXUP_PC_AFTER_BREAK(regs); 96 pc = PC_REGS(regs); 97 } 98 #endif 99 100 #ifdef SOFTWARE_SSTEP 101 /* 102 * If we stopped at one of the single-step breakpoints, say it's not 103 * really a breakpoint so that we don't skip over the real instruction. 104 */ 105 if (db_taken_bkpt.address == pc || db_not_taken_bkpt.address == pc) 106 *is_breakpoint = false; 107 #endif /* SOFTWARE_SSTEP */ 108 109 db_clear_single_step(regs); 110 db_clear_breakpoints(); 111 db_clear_watchpoints(); 112 113 /* 114 * Now check for a breakpoint at this address. 115 */ 116 bkpt = db_find_breakpoint_here(pc); 117 if (bkpt) { 118 if (--bkpt->count == 0) { 119 bkpt->count = bkpt->init_count; 120 *is_breakpoint = true; 121 return (true); /* stop here */ 122 } 123 } else if (*is_breakpoint) { 124 #ifdef PC_ADVANCE 125 PC_ADVANCE(regs); 126 #else 127 PC_REGS(regs) += BKPT_SIZE; 128 #endif 129 } 130 131 *is_breakpoint = false; 132 133 if (db_run_mode == STEP_INVISIBLE) { 134 db_run_mode = STEP_CONTINUE; 135 return (false); /* continue */ 136 } 137 if (db_run_mode == STEP_COUNT) { 138 return (false); /* continue */ 139 } 140 if (db_run_mode == STEP_ONCE) { 141 if (--db_loop_count > 0) { 142 if (db_sstep_print) { 143 db_printf("\t\t"); 144 db_print_loc_and_inst(pc); 145 db_printf("\n"); 146 } 147 return (false); /* continue */ 148 } 149 } 150 if (db_run_mode == STEP_RETURN) { 151 db_expr_t ins = db_get_value(pc, sizeof(int), false); 152 153 /* continue until matching return */ 154 155 if (!inst_trap_return(ins) && 156 (!inst_return(ins) || --db_call_depth != 0)) { 157 if (db_sstep_print) { 158 if (inst_call(ins) || inst_return(ins)) { 159 int i; 160 161 db_printf("[after %6d] ", 162 db_inst_count); 163 for (i = db_call_depth; --i > 0; ) 164 db_printf(" "); 165 db_print_loc_and_inst(pc); 166 db_printf("\n"); 167 } 168 } 169 if (inst_call(ins)) 170 db_call_depth++; 171 return (false); /* continue */ 172 } 173 } 174 if (db_run_mode == STEP_CALLT) { 175 db_expr_t ins = db_get_value(pc, sizeof(int), false); 176 177 /* continue until call or return */ 178 179 if (!inst_call(ins) && 180 !inst_return(ins) && 181 !inst_trap_return(ins)) { 182 return (false); /* continue */ 183 } 184 } 185 db_run_mode = STEP_NONE; 186 return (true); 187 } 188 189 void 190 db_restart_at_pc(db_regs_t *regs, bool watchpt) 191 { 192 db_addr_t pc = PC_REGS(regs); 193 #ifdef SOFTWARE_SSTEP 194 db_addr_t brpc; 195 #endif 196 197 if ((db_run_mode == STEP_COUNT) || 198 (db_run_mode == STEP_RETURN) || 199 (db_run_mode == STEP_CALLT)) { 200 db_expr_t ins __unused; 201 202 /* 203 * We are about to execute this instruction, 204 * so count it now. 205 */ 206 ins = db_get_value(pc, sizeof(int), false); 207 db_inst_count++; 208 db_load_count += inst_load(ins); 209 db_store_count += inst_store(ins); 210 211 #ifdef SOFTWARE_SSTEP 212 /* 213 * Account for instructions in delay slots. 214 */ 215 brpc = next_instr_address(pc, true); 216 if ((brpc != pc) && 217 (inst_branch(ins) || inst_call(ins) || inst_return(ins))) { 218 ins = db_get_value(brpc, sizeof(int), false); 219 db_inst_count++; 220 db_load_count += inst_load(ins); 221 db_store_count += inst_store(ins); 222 } 223 #endif 224 } 225 226 if (db_run_mode == STEP_CONTINUE) { 227 if (watchpt || db_find_breakpoint_here(pc)) { 228 /* 229 * Step over breakpoint/watchpoint. 230 */ 231 db_run_mode = STEP_INVISIBLE; 232 db_set_single_step(regs); 233 } else { 234 db_set_breakpoints(); 235 db_set_watchpoints(); 236 } 237 } else { 238 db_set_single_step(regs); 239 } 240 } 241 242 void 243 db_single_step(db_regs_t *regs) 244 { 245 246 if (db_run_mode == STEP_CONTINUE) { 247 db_run_mode = STEP_INVISIBLE; 248 db_set_single_step(regs); 249 } 250 } 251 252 /* single-step */ 253 /*ARGSUSED*/ 254 void 255 db_single_step_cmd(db_expr_t addr, bool have_addr, 256 db_expr_t count, const char *modif) 257 { 258 bool print = false; 259 260 if (count == -1) 261 count = 1; 262 263 if (modif[0] == 'p') 264 print = true; 265 266 db_run_mode = STEP_ONCE; 267 db_loop_count = count; 268 db_sstep_print = print; 269 db_inst_count = 0; 270 db_load_count = 0; 271 db_store_count = 0; 272 273 db_cmd_loop_done = true; 274 } 275 276 /* trace and print until call/return */ 277 /*ARGSUSED*/ 278 void 279 db_trace_until_call_cmd(db_expr_t addr, bool have_addr, 280 db_expr_t count, const char *modif) 281 { 282 bool print = false; 283 284 if (modif[0] == 'p') 285 print = true; 286 287 db_run_mode = STEP_CALLT; 288 db_sstep_print = print; 289 db_inst_count = 0; 290 db_load_count = 0; 291 db_store_count = 0; 292 293 db_cmd_loop_done = true; 294 } 295 296 /*ARGSUSED*/ 297 void 298 db_trace_until_matching_cmd(db_expr_t addr, bool have_addr, 299 db_expr_t count, const char *modif) 300 { 301 bool print = false; 302 303 if (modif[0] == 'p') 304 print = true; 305 306 db_run_mode = STEP_RETURN; 307 db_call_depth = 1; 308 db_sstep_print = print; 309 db_inst_count = 0; 310 db_load_count = 0; 311 db_store_count = 0; 312 313 db_cmd_loop_done = true; 314 } 315 316 /* continue */ 317 /*ARGSUSED*/ 318 void 319 db_continue_cmd(db_expr_t addr, bool have_addr, 320 db_expr_t count, const char *modif) 321 { 322 323 if (modif[0] == 'c') 324 db_run_mode = STEP_COUNT; 325 else 326 db_run_mode = STEP_CONTINUE; 327 db_inst_count = 0; 328 db_load_count = 0; 329 db_store_count = 0; 330 331 db_cmd_loop_done = true; 332 } 333 #endif /* DDB */ 334 335 #ifdef SOFTWARE_SSTEP 336 /* 337 * Software implementation of single-stepping. 338 * If your machine does not have a trace mode 339 * similar to the vax or sun ones you can use 340 * this implementation, done for the mips. 341 * Just define the above conditional and provide 342 * the functions/macros defined below. 343 * 344 * bool inst_branch(int inst) 345 * bool inst_call(int inst) 346 * returns true if the instruction might branch 347 * 348 * bool inst_return(int inst) 349 * returns true is the instruction will return to its caller 350 * 351 * bool inst_unconditional_flow_transfer(int inst) 352 * returns true if the instruction is an unconditional 353 * transter of flow (i.e. unconditional branch) 354 * 355 * db_addr_t branch_taken(int inst, db_addr_t pc, db_regs_t *regs) 356 * returns the target address of the branch 357 * 358 * db_addr_t next_instr_address(db_addr_t pc, bool bd) 359 * returns the address of the first instruction following the 360 * one at "pc", which is either in the taken path of the branch 361 * (bd == true) or not. This is for machines (e.g. mips) with 362 * branch delays. 363 * 364 * A single-step may involve at most 2 breakpoints - 365 * one for branch-not-taken and one for branch taken. 366 * If one of these addresses does not already have a breakpoint, 367 * we allocate a breakpoint and save it here. 368 * These breakpoints are deleted on return. 369 */ 370 371 #if !defined(DDB) 372 /* XXX - don't check for existing breakpoints in KGDB-only case */ 373 #define db_find_breakpoint_here(pc) (0) 374 #endif 375 376 void 377 db_set_single_step(db_regs_t *regs) 378 { 379 db_addr_t pc = PC_REGS(regs), brpc = pc; 380 bool unconditional; 381 unsigned int inst; 382 383 /* 384 * User was stopped at pc, e.g. the instruction 385 * at pc was not executed. 386 */ 387 inst = db_get_value(pc, sizeof(int), false); 388 if (inst_branch(inst) || inst_call(inst) || inst_return(inst)) { 389 brpc = branch_taken(inst, pc, regs); 390 if (brpc != pc) { /* self-branches are hopeless */ 391 db_set_temp_breakpoint(&db_taken_bkpt, brpc); 392 } else 393 db_taken_bkpt.address = 0; 394 pc = next_instr_address(pc, true); 395 } 396 397 /* 398 * Check if this control flow instruction is an 399 * unconditional transfer. 400 */ 401 unconditional = inst_unconditional_flow_transfer(inst); 402 403 pc = next_instr_address(pc, false); 404 405 /* 406 * We only set the sequential breakpoint if previous 407 * instruction was not an unconditional change of flow 408 * control. If the previous instruction is an 409 * unconditional change of flow control, setting a 410 * breakpoint in the next sequential location may set 411 * a breakpoint in data or in another routine, which 412 * could screw up in either the program or the debugger. 413 * (Consider, for instance, that the next sequential 414 * instruction is the start of a routine needed by the 415 * debugger.) 416 * 417 * Also, don't set both the taken and not-taken breakpoints 418 * in the same place even if the MD code would otherwise 419 * have us do so. 420 */ 421 if (unconditional == false && 422 db_find_breakpoint_here(pc) == 0 && 423 pc != brpc) 424 db_set_temp_breakpoint(&db_not_taken_bkpt, pc); 425 else 426 db_not_taken_bkpt.address = 0; 427 } 428 429 void 430 db_clear_single_step(db_regs_t *regs) 431 { 432 433 if (db_taken_bkpt.address != 0) 434 db_delete_temp_breakpoint(&db_taken_bkpt); 435 436 if (db_not_taken_bkpt.address != 0) 437 db_delete_temp_breakpoint(&db_not_taken_bkpt); 438 } 439 440 void 441 db_set_temp_breakpoint(db_breakpoint_t bkpt, db_addr_t addr) 442 { 443 444 bkpt->map = NULL; 445 bkpt->address = addr; 446 /* bkpt->flags = BKPT_TEMP; - this is not used */ 447 bkpt->init_count = 1; 448 bkpt->count = 1; 449 450 bkpt->bkpt_inst = db_get_value(bkpt->address, BKPT_SIZE, false); 451 db_put_value(bkpt->address, BKPT_SIZE, 452 BKPT_SET(bkpt->bkpt_inst, bkpt->address)); 453 } 454 455 void 456 db_delete_temp_breakpoint(db_breakpoint_t bkpt) 457 { 458 459 db_put_value(bkpt->address, BKPT_SIZE, bkpt->bkpt_inst); 460 bkpt->address = 0; 461 } 462 #endif /* SOFTWARE_SSTEP */ 463
Indexes created Sun Sep 21 16:09:51 GMT 2025