2 * Mach Operating System
3 * Copyright (c) 1991,1990 Carnegie Mellon University
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.
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.
16 * Carnegie Mellon requests users of this software to return to
18 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
19 * School of Computer Science
20 * Carnegie Mellon University
21 * Pittsburgh PA 15213-3890
23 * any improvements or extensions that they make and grant Carnegie the
24 * rights to redistribute these changes.
30 * Author: David B. Golub, Carnegie Mellon University
35 * Commands to run process.
37 #include <sys/param.h>
42 #include <ddb/db_break.h>
43 #include <ddb/db_access.h>
45 static int db_run_mode;
50 #define STEP_CONTINUE 4
51 #define STEP_INVISIBLE 5
54 static boolean_t db_sstep_print;
55 static int db_loop_count;
56 static int db_call_depth;
62 #ifndef db_set_single_step
63 extern void db_set_single_step __P((db_regs_t *regs));
65 #ifndef db_clear_single_step
66 extern void db_clear_single_step __P((db_regs_t *regs));
70 static void db_single_step __P((db_regs_t *regs));
74 db_stop_at_pc(is_breakpoint)
75 boolean_t *is_breakpoint;
77 register db_addr_t pc;
78 register db_breakpoint_t bkpt;
80 db_clear_single_step(DDB_REGS);
81 db_clear_breakpoints();
82 db_clear_watchpoints();
83 pc = PC_REGS(DDB_REGS);
85 #ifdef FIXUP_PC_AFTER_BREAK
88 * Breakpoint trap. Fix up the PC if the
89 * machine requires it.
92 pc = PC_REGS(DDB_REGS);
97 * Now check for a breakpoint at this address.
99 bkpt = db_find_breakpoint_here(pc);
101 if (--bkpt->count == 0) {
102 bkpt->count = bkpt->init_count;
103 *is_breakpoint = TRUE;
104 return (TRUE); /* stop here */
106 } else if (*is_breakpoint) {
107 #ifdef __i386__ /* XXx */
108 ddb_regs.tf_eip += 1;
112 *is_breakpoint = FALSE;
114 if (db_run_mode == STEP_INVISIBLE) {
115 db_run_mode = STEP_CONTINUE;
116 return (FALSE); /* continue */
118 if (db_run_mode == STEP_COUNT) {
119 return (FALSE); /* continue */
121 if (db_run_mode == STEP_ONCE) {
122 if (--db_loop_count > 0) {
123 if (db_sstep_print) {
125 db_print_loc_and_inst(pc);
128 return (FALSE); /* continue */
131 if (db_run_mode == STEP_RETURN) {
132 db_expr_t ins = db_get_value(pc, sizeof(int), FALSE);
134 /* continue until matching return */
136 if (!inst_trap_return(ins) &&
137 (!inst_return(ins) || --db_call_depth != 0)) {
138 if (db_sstep_print) {
139 if (inst_call(ins) || inst_return(ins)) {
142 db_printf("[after %6d] ", db_inst_count);
143 for (i = db_call_depth; --i > 0; )
145 db_print_loc_and_inst(pc);
151 return (FALSE); /* continue */
154 if (db_run_mode == STEP_CALLT) {
155 db_expr_t ins = db_get_value(pc, sizeof(int), FALSE);
157 /* continue until call or return */
159 if (!inst_call(ins) &&
161 !inst_trap_return(ins)) {
162 return (FALSE); /* continue */
165 db_run_mode = STEP_NONE;
170 db_restart_at_pc(watchpt)
173 register db_addr_t pc = PC_REGS(DDB_REGS);
175 if ((db_run_mode == STEP_COUNT) ||
176 (db_run_mode == STEP_RETURN) ||
177 (db_run_mode == STEP_CALLT)) {
181 * We are about to execute this instruction,
185 ins = db_get_value(pc, sizeof(int), FALSE);
187 db_load_count += inst_load(ins);
188 db_store_count += inst_store(ins);
189 #ifdef SOFTWARE_SSTEP
190 /* XXX works on mips, but... */
191 if (inst_branch(ins) || inst_call(ins)) {
192 ins = db_get_value(next_instr_address(pc,1),
195 db_load_count += inst_load(ins);
196 db_store_count += inst_store(ins);
198 #endif SOFTWARE_SSTEP
201 if (db_run_mode == STEP_CONTINUE) {
202 if (watchpt || db_find_breakpoint_here(pc)) {
204 * Step over breakpoint/watchpoint.
206 db_run_mode = STEP_INVISIBLE;
207 db_set_single_step(DDB_REGS);
209 db_set_breakpoints();
210 db_set_watchpoints();
213 db_set_single_step(DDB_REGS);
222 if (db_run_mode == STEP_CONTINUE) {
223 db_run_mode = STEP_INVISIBLE;
224 db_set_single_step(regs);
229 #ifdef SOFTWARE_SSTEP
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.
239 * inst_branch(), returns true if the instruction might branch
241 * branch_taken(), return the address the instruction might
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
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.
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.
259 db_breakpoint_t db_not_taken_bkpt = 0;
260 db_breakpoint_t db_taken_bkpt = 0;
263 db_set_single_step(regs)
264 register db_regs_t *regs;
266 db_addr_t pc = PC_REGS(regs), brpc;
270 * User was stopped at pc, e.g. the instruction
271 * at pc was not executed.
273 inst = db_get_value(pc, sizeof(int), FALSE);
274 if (inst_branch(inst) || inst_call(inst)) {
275 brpc = branch_taken(inst, pc, regs);
276 if (brpc != pc) { /* self-branches are hopeless */
277 db_taken_bkpt = db_set_temp_breakpoint(brpc);
279 pc = next_instr_address(pc,1);
281 pc = next_instr_address(pc,0);
282 db_not_taken_bkpt = db_set_temp_breakpoint(pc);
286 db_clear_single_step(regs)
290 if (db_not_taken_bkpt != 0) {
291 db_delete_temp_breakpoint(db_not_taken_bkpt);
292 db_not_taken_bkpt = 0;
294 if (db_taken_bkpt != 0) {
295 db_delete_temp_breakpoint(db_taken_bkpt);
300 #endif SOFTWARE_SSTEP
302 extern int db_cmd_loop_done;
307 db_single_step_cmd(addr, have_addr, count, modif)
313 boolean_t print = FALSE;
321 db_run_mode = STEP_ONCE;
322 db_loop_count = count;
323 db_sstep_print = print;
328 db_cmd_loop_done = 1;
331 /* trace and print until call/return */
334 db_trace_until_call_cmd(addr, have_addr, count, modif)
340 boolean_t print = FALSE;
345 db_run_mode = STEP_CALLT;
346 db_sstep_print = print;
351 db_cmd_loop_done = 1;
356 db_trace_until_matching_cmd(addr, have_addr, count, modif)
362 boolean_t print = FALSE;
367 db_run_mode = STEP_RETURN;
369 db_sstep_print = print;
374 db_cmd_loop_done = 1;
380 db_continue_cmd(addr, have_addr, count, modif)
387 db_run_mode = STEP_COUNT;
389 db_run_mode = STEP_CONTINUE;
394 db_cmd_loop_done = 1;