| File: | ddb/db_run.c |
| Warning: | line 189, column 3 Value stored to 'ins' is never read |
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| 1 | /* $OpenBSD: db_run.c,v 1.31 2023/03/08 04:43:07 guenther Exp $ */ |
| 2 | /* $NetBSD: db_run.c,v 1.8 1996/02/05 01:57:12 christos Exp $ */ |
| 3 | |
| 4 | /* |
| 5 | * Mach Operating System |
| 6 | * Copyright (c) 1993,1992,1991,1990 Carnegie Mellon University |
| 7 | * All Rights Reserved. |
| 8 | * |
| 9 | * Permission to use, copy, modify and distribute this software and its |
| 10 | * documentation is hereby granted, provided that both the copyright |
| 11 | * notice and this permission notice appear in all copies of the |
| 12 | * software, derivative works or modified versions, and any portions |
| 13 | * thereof, and that both notices appear in supporting documentation. |
| 14 | * |
| 15 | * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" |
| 16 | * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR |
| 17 | * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. |
| 18 | * |
| 19 | * Carnegie Mellon requests users of this software to return to |
| 20 | * |
| 21 | * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU |
| 22 | * School of Computer Science |
| 23 | * Carnegie Mellon University |
| 24 | * Pittsburgh PA 15213-3890 |
| 25 | * |
| 26 | * any improvements or extensions that they make and grant Carnegie Mellon |
| 27 | * the rights to redistribute these changes. |
| 28 | * |
| 29 | * Author: David B. Golub, Carnegie Mellon University |
| 30 | * Date: 7/90 |
| 31 | */ |
| 32 | |
| 33 | /* |
| 34 | * Commands to run process. |
| 35 | */ |
| 36 | #include <sys/param.h> |
| 37 | #include <sys/systm.h> |
| 38 | |
| 39 | #include <machine/db_machdep.h> |
| 40 | |
| 41 | #include <ddb/db_run.h> |
| 42 | #include <ddb/db_break.h> |
| 43 | #include <ddb/db_access.h> |
| 44 | |
| 45 | #ifdef SOFTWARE_SSTEP |
| 46 | db_breakpoint_t db_not_taken_bkpt = 0; |
| 47 | db_breakpoint_t db_taken_bkpt = 0; |
| 48 | #endif |
| 49 | |
| 50 | int db_inst_count; |
| 51 | |
| 52 | #include <ddb/db_watch.h> |
| 53 | #include <ddb/db_output.h> |
| 54 | #include <ddb/db_sym.h> |
| 55 | #include <ddb/db_extern.h> |
| 56 | |
| 57 | int db_run_mode; |
| 58 | #define STEP_NONE0 0 |
| 59 | #define STEP_ONCE1 1 |
| 60 | #define STEP_RETURN2 2 |
| 61 | #define STEP_CALLT3 3 |
| 62 | #define STEP_CONTINUE4 4 |
| 63 | #define STEP_INVISIBLE5 5 |
| 64 | #define STEP_COUNT6 6 |
| 65 | |
| 66 | int db_sstep_print; |
| 67 | int db_loop_count; |
| 68 | int db_call_depth; |
| 69 | |
| 70 | int |
| 71 | db_stop_at_pc(db_regs_t *regs, int *is_breakpoint) |
| 72 | { |
| 73 | vaddr_t pc, old_pc; |
| 74 | db_breakpoint_t bkpt; |
| 75 | |
| 76 | db_clear_breakpoints(); |
| 77 | db_clear_watchpoints(); |
| 78 | old_pc = pc = PC_REGS(regs)((vaddr_t)(regs)->tf_rip); |
| 79 | |
| 80 | #ifdef FIXUP_PC_AFTER_BREAK |
| 81 | if (*is_breakpoint) { |
| 82 | /* |
| 83 | * Breakpoint trap. Fix up the PC if the |
| 84 | * machine requires it. |
| 85 | */ |
| 86 | FIXUP_PC_AFTER_BREAK(regs)((regs)->tf_rip -= (1)); |
| 87 | pc = PC_REGS(regs)((vaddr_t)(regs)->tf_rip); |
| 88 | } |
| 89 | #endif |
| 90 | |
| 91 | /* |
| 92 | * Now check for a breakpoint at this address. |
| 93 | */ |
| 94 | bkpt = db_find_breakpoint(pc); |
| 95 | if (bkpt) { |
| 96 | if (--bkpt->count == 0) { |
| 97 | db_clear_single_step(regs)((regs)->tf_rflags &= ~0x00000100); |
| 98 | bkpt->count = bkpt->init_count; |
| 99 | *is_breakpoint = 1; |
| 100 | return 1; /* stop here */ |
| 101 | } |
| 102 | } else if (*is_breakpoint |
| 103 | #ifdef SOFTWARE_SSTEP |
| 104 | && !((db_taken_bkpt && db_taken_bkpt->address == pc) || |
| 105 | (db_not_taken_bkpt && db_not_taken_bkpt->address == pc)) |
| 106 | #endif |
| 107 | ) { |
| 108 | #ifdef PC_ADVANCE |
| 109 | PC_ADVANCE(regs); |
| 110 | #else |
| 111 | # ifdef SET_PC_REGS |
| 112 | SET_PC_REGS(regs, old_pc)(regs)->tf_rip = (int64_t)(old_pc); |
| 113 | # else |
| 114 | PC_REGS(regs)((vaddr_t)(regs)->tf_rip) = old_pc; |
| 115 | # endif |
| 116 | #endif |
| 117 | } |
| 118 | db_clear_single_step(regs)((regs)->tf_rflags &= ~0x00000100); |
| 119 | |
| 120 | *is_breakpoint = 0; |
| 121 | |
| 122 | if (db_run_mode == STEP_INVISIBLE5) { |
| 123 | db_run_mode = STEP_CONTINUE4; |
| 124 | return 0; /* continue */ |
| 125 | } |
| 126 | if (db_run_mode == STEP_COUNT6) { |
| 127 | return 0; /* continue */ |
| 128 | } |
| 129 | if (db_run_mode == STEP_ONCE1) { |
| 130 | if (--db_loop_count > 0) { |
| 131 | if (db_sstep_print) { |
| 132 | db_printf("\t\t"); |
| 133 | db_print_loc_and_inst(pc); |
| 134 | db_printf("\n"); |
| 135 | } |
| 136 | return 0; /* continue */ |
| 137 | } |
| 138 | } |
| 139 | if (db_run_mode == STEP_RETURN2) { |
| 140 | db_expr_t ins = db_get_value(pc, sizeof(int), 0); |
| 141 | |
| 142 | /* continue until matching return */ |
| 143 | |
| 144 | if (!inst_trap_return(ins)(((ins)&0xff) == 0xcf) && |
| 145 | (!inst_return(ins)(((ins)&0xff) == 0xc3) || --db_call_depth != 0)) { |
| 146 | if (db_sstep_print) { |
| 147 | if (inst_call(ins)(((ins)&0xff) == 0xe8 || (((ins)&0xff) == 0xff && ((ins)&0x3800) == 0x1000)) || inst_return(ins)(((ins)&0xff) == 0xc3)) { |
| 148 | int i; |
| 149 | |
| 150 | db_printf("[after %6d] ", db_inst_count); |
| 151 | for (i = db_call_depth; --i > 0; ) |
| 152 | db_printf(" "); |
| 153 | db_print_loc_and_inst(pc); |
| 154 | db_printf("\n"); |
| 155 | } |
| 156 | } |
| 157 | if (inst_call(ins)(((ins)&0xff) == 0xe8 || (((ins)&0xff) == 0xff && ((ins)&0x3800) == 0x1000))) |
| 158 | db_call_depth++; |
| 159 | return 0; /* continue */ |
| 160 | } |
| 161 | } |
| 162 | if (db_run_mode == STEP_CALLT3) { |
| 163 | db_expr_t ins = db_get_value(pc, sizeof(int), 0); |
| 164 | |
| 165 | /* continue until call or return */ |
| 166 | |
| 167 | if (!inst_call(ins)(((ins)&0xff) == 0xe8 || (((ins)&0xff) == 0xff && ((ins)&0x3800) == 0x1000)) && !inst_return(ins)(((ins)&0xff) == 0xc3) && |
| 168 | !inst_trap_return(ins)(((ins)&0xff) == 0xcf)) { |
| 169 | return 0; /* continue */ |
| 170 | } |
| 171 | } |
| 172 | db_run_mode = STEP_NONE0; |
| 173 | return 1; |
| 174 | } |
| 175 | |
| 176 | void |
| 177 | db_restart_at_pc(db_regs_t *regs, int watchpt) |
| 178 | { |
| 179 | vaddr_t pc = PC_REGS(regs)((vaddr_t)(regs)->tf_rip); |
| 180 | |
| 181 | if ((db_run_mode == STEP_COUNT6) || (db_run_mode == STEP_RETURN2) || |
| 182 | (db_run_mode == STEP_CALLT3)) { |
| 183 | db_expr_t ins; |
| 184 | |
| 185 | /* |
| 186 | * We are about to execute this instruction, |
| 187 | * so count it now. |
| 188 | */ |
| 189 | ins = db_get_value(pc, sizeof(int), 0); |
Value stored to 'ins' is never read | |
| 190 | db_inst_count++; |
| 191 | #ifdef SOFTWARE_SSTEP |
| 192 | /* XXX works on mips, but... */ |
| 193 | if (inst_branch(ins) || inst_call(ins)(((ins)&0xff) == 0xe8 || (((ins)&0xff) == 0xff && ((ins)&0x3800) == 0x1000))) { |
| 194 | ins = db_get_value(next_instr_address(pc, 1), |
| 195 | sizeof(int), 0); |
| 196 | db_inst_count++; |
| 197 | } |
| 198 | #endif /* SOFTWARE_SSTEP */ |
| 199 | } |
| 200 | |
| 201 | if (db_run_mode == STEP_CONTINUE4) { |
| 202 | if (watchpt || db_find_breakpoint(pc)) { |
| 203 | /* |
| 204 | * Step over breakpoint/watchpoint. |
| 205 | */ |
| 206 | db_run_mode = STEP_INVISIBLE5; |
| 207 | db_set_single_step(regs)((regs)->tf_rflags |= 0x00000100); |
| 208 | } else { |
| 209 | db_set_breakpoints(); |
| 210 | db_set_watchpoints(); |
| 211 | } |
| 212 | } else { |
| 213 | db_set_single_step(regs)((regs)->tf_rflags |= 0x00000100); |
| 214 | } |
| 215 | } |
| 216 | |
| 217 | void |
| 218 | db_single_step(db_regs_t *regs) |
| 219 | { |
| 220 | if (db_run_mode == STEP_CONTINUE4) { |
| 221 | db_run_mode = STEP_INVISIBLE5; |
| 222 | db_set_single_step(regs)((regs)->tf_rflags |= 0x00000100); |
| 223 | } |
| 224 | } |
| 225 | |
| 226 | /* single-step */ |
| 227 | void |
| 228 | db_single_step_cmd(db_expr_t addr, int have_addr, db_expr_t count, char *modif) |
| 229 | { |
| 230 | int print = 0; |
| 231 | |
| 232 | if (count == -1) |
| 233 | count = 1; |
| 234 | |
| 235 | if (modif[0] == 'p') |
| 236 | print = 1; |
| 237 | |
| 238 | db_run_mode = STEP_ONCE1; |
| 239 | db_loop_count = count; |
| 240 | db_sstep_print = print; |
| 241 | db_inst_count = 0; |
| 242 | |
| 243 | db_cmd_loop_done = 1; |
| 244 | } |
| 245 | |
| 246 | /* trace and print until call/return */ |
| 247 | void |
| 248 | db_trace_until_call_cmd(db_expr_t addr, int have_addr, db_expr_t count, |
| 249 | char *modif) |
| 250 | { |
| 251 | int print = 0; |
| 252 | |
| 253 | if (modif[0] == 'p') |
| 254 | print = 1; |
| 255 | |
| 256 | db_run_mode = STEP_CALLT3; |
| 257 | db_sstep_print = print; |
| 258 | db_inst_count = 0; |
| 259 | |
| 260 | db_cmd_loop_done = 1; |
| 261 | } |
| 262 | |
| 263 | void |
| 264 | db_trace_until_matching_cmd(db_expr_t addr, int have_addr, db_expr_t count, |
| 265 | char *modif) |
| 266 | { |
| 267 | int print = 0; |
| 268 | |
| 269 | if (modif[0] == 'p') |
| 270 | print = 1; |
| 271 | |
| 272 | db_run_mode = STEP_RETURN2; |
| 273 | db_call_depth = 1; |
| 274 | db_sstep_print = print; |
| 275 | db_inst_count = 0; |
| 276 | |
| 277 | db_cmd_loop_done = 1; |
| 278 | } |
| 279 | |
| 280 | /* continue */ |
| 281 | void |
| 282 | db_continue_cmd(db_expr_t addr, int have_addr, db_expr_t count, char *modif) |
| 283 | { |
| 284 | if (modif[0] == 'c') |
| 285 | db_run_mode = STEP_COUNT6; |
| 286 | else |
| 287 | db_run_mode = STEP_CONTINUE4; |
| 288 | db_inst_count = 0; |
| 289 | |
| 290 | db_cmd_loop_done = 1; |
| 291 | } |
| 292 | |
| 293 | #ifdef SOFTWARE_SSTEP |
| 294 | /* |
| 295 | * Software implementation of single-stepping. |
| 296 | * If your machine does not have a trace mode |
| 297 | * similar to the vax or sun ones you can use |
| 298 | * this implementation, done for the mips. |
| 299 | * Just define the above conditional and provide |
| 300 | * the functions/macros defined below. |
| 301 | * |
| 302 | * extern int |
| 303 | * inst_branch(ins), returns true if the instruction might branch |
| 304 | * extern unsigned |
| 305 | * branch_taken(ins, pc, getreg_val, regs), |
| 306 | * return the address the instruction might |
| 307 | * branch to |
| 308 | * getreg_val(regs, reg), return the value of a user register, |
| 309 | * as indicated in the hardware instruction |
| 310 | * encoding, e.g. 8 for r8 |
| 311 | * |
| 312 | * next_instr_address(pc, bd) returns the address of the first |
| 313 | * instruction following the one at "pc", |
| 314 | * which is either in the taken path of |
| 315 | * the branch (bd==1) or not. This is |
| 316 | * for machines (mips) with branch delays. |
| 317 | * |
| 318 | * A single-step may involve at most 2 breakpoints - |
| 319 | * one for branch-not-taken and one for branch taken. |
| 320 | * If one of these addresses does not already have a breakpoint, |
| 321 | * we allocate a breakpoint and save it here. |
| 322 | * These breakpoints are deleted on return. |
| 323 | */ |
| 324 | |
| 325 | void |
| 326 | db_set_single_step(db_regs_t *regs)((db_regs_t *regs)->tf_rflags |= 0x00000100) |
| 327 | { |
| 328 | vaddr_t pc = PC_REGS(regs)((vaddr_t)(regs)->tf_rip); |
| 329 | #ifndef SOFTWARE_SSTEP_EMUL |
| 330 | vaddr_t brpc; |
| 331 | u_int inst; |
| 332 | |
| 333 | /* |
| 334 | * User was stopped at pc, e.g. the instruction |
| 335 | * at pc was not executed. |
| 336 | */ |
| 337 | inst = db_get_value(pc, sizeof(int), 0); |
| 338 | if (inst_branch(inst) || inst_call(inst)(((inst)&0xff) == 0xe8 || (((inst)&0xff) == 0xff && ((inst)&0x3800) == 0x1000)) || inst_return(inst)(((inst)&0xff) == 0xc3)) { |
| 339 | brpc = branch_taken(inst, pc, getreg_val, regs); |
| 340 | if (brpc != pc) { /* self-branches are hopeless */ |
| 341 | db_taken_bkpt = db_set_temp_breakpoint(brpc); |
| 342 | } |
| 343 | #if 0 |
| 344 | /* XXX this seems like a true bug, no? */ |
| 345 | pc = next_instr_address(pc, 1); |
| 346 | #endif |
| 347 | } |
| 348 | #endif /*SOFTWARE_SSTEP_EMUL*/ |
| 349 | pc = next_instr_address(pc, 0); |
| 350 | db_not_taken_bkpt = db_set_temp_breakpoint(pc); |
| 351 | } |
| 352 | |
| 353 | void |
| 354 | db_clear_single_step(db_regs_t *regs)((db_regs_t *regs)->tf_rflags &= ~0x00000100) |
| 355 | { |
| 356 | if (db_taken_bkpt != 0) { |
| 357 | db_delete_temp_breakpoint(db_taken_bkpt); |
| 358 | db_taken_bkpt = 0; |
| 359 | } |
| 360 | if (db_not_taken_bkpt != 0) { |
| 361 | db_delete_temp_breakpoint(db_not_taken_bkpt); |
| 362 | db_not_taken_bkpt = 0; |
| 363 | } |
| 364 | } |
| 365 | |
| 366 | #endif /* SOFTWARE_SSTEP */ |