| 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@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 | |