1 /*-
2 * SPDX-License-Identifier: MIT-CMU
3 *
4 * Mach Operating System
5 * Copyright (c) 1991,1990 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
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 /*
29 * Author: David B. Golub, Carnegie Mellon University
30 * Date: 7/90
31 */
32
33 /*
34 * Commands to run process.
35 */
36
37 #include <sys/cdefs.h>
38 #include <sys/param.h>
39 #include <sys/kdb.h>
40 #include <sys/proc.h>
41 #include <sys/reg.h>
42 #include <sys/systm.h>
43
44 #include <machine/kdb.h>
45 #include <machine/pcb.h>
46
47 #include <vm/vm.h>
48
49 #include <ddb/ddb.h>
50 #include <ddb/db_access.h>
51 #include <ddb/db_break.h>
52 #include <ddb/db_command.h>
53
54 #define STEP_ONCE 1
55 #define STEP_RETURN 2
56 #define STEP_CALLT 3
57 #define STEP_CONTINUE 4
58 #define STEP_INVISIBLE 5
59 #define STEP_COUNT 6
60 static int db_run_mode = STEP_CONTINUE;
61
62 static bool db_sstep_multiple;
63 static bool db_sstep_print;
64 static int db_loop_count;
65 static int db_call_depth;
66
67 int db_inst_count;
68 int db_load_count;
69 int db_store_count;
70
71 bool
db_stop_at_pc(int type,int code,bool * is_breakpoint,bool * is_watchpoint)72 db_stop_at_pc(int type, int code, bool *is_breakpoint, bool *is_watchpoint)
73 {
74 db_addr_t pc;
75 db_breakpoint_t bkpt;
76
77 *is_breakpoint = IS_BREAKPOINT_TRAP(type, code);
78 *is_watchpoint = IS_WATCHPOINT_TRAP(type, code);
79 pc = PC_REGS();
80
81 db_clear_single_step();
82 db_clear_breakpoints();
83 db_clear_watchpoints();
84
85 #ifdef FIXUP_PC_AFTER_BREAK
86 if (*is_breakpoint) {
87 /*
88 * Breakpoint trap. Fix up the PC if the
89 * machine requires it.
90 */
91 FIXUP_PC_AFTER_BREAK
92 pc = PC_REGS();
93 }
94 #endif
95
96 /*
97 * Now check for a breakpoint at this address.
98 */
99 bkpt = db_find_breakpoint_here(pc);
100 if (bkpt) {
101 if (--bkpt->count == 0) {
102 bkpt->count = bkpt->init_count;
103 *is_breakpoint = true;
104 return (true); /* stop here */
105 }
106 return (false); /* continue the countdown */
107 } else if (*is_breakpoint) {
108 #ifdef BKPT_SKIP
109 BKPT_SKIP;
110 #endif
111 }
112
113 *is_breakpoint = false; /* might be a breakpoint, but not ours */
114
115 /*
116 * If not stepping, then silently ignore single-step traps
117 * (except for clearing the single-step-flag above).
118 *
119 * If stepping, then abort if the trap type is unexpected.
120 * Breakpoints owned by us are expected and were handled above.
121 * Single-steps are expected and are handled below. All others
122 * are unexpected.
123 *
124 * Only do either of these if the MD layer claims to classify
125 * single-step traps unambiguously (by defining IS_SSTEP_TRAP).
126 * Otherwise, fall through to the bad historical behaviour
127 * given by turning unexpected traps into expected traps: if not
128 * stepping, then expect only breakpoints and stop, and if
129 * stepping, then expect only single-steps and step.
130 */
131 #ifdef IS_SSTEP_TRAP
132 if (db_run_mode == STEP_CONTINUE && IS_SSTEP_TRAP(type, code))
133 return (false);
134 if (db_run_mode != STEP_CONTINUE && !IS_SSTEP_TRAP(type, code)) {
135 printf("Stepping aborted\n");
136 return (true);
137 }
138 #endif
139
140 if (db_run_mode == STEP_INVISIBLE) {
141 db_run_mode = STEP_CONTINUE;
142 return (false); /* continue */
143 }
144 if (db_run_mode == STEP_COUNT) {
145 return (false); /* continue */
146 }
147 if (db_run_mode == STEP_ONCE) {
148 if (--db_loop_count > 0) {
149 if (db_sstep_print) {
150 db_printf("\t\t");
151 db_print_loc_and_inst(pc);
152 }
153 return (false); /* continue */
154 }
155 }
156 if (db_run_mode == STEP_RETURN) {
157 /* continue until matching return */
158 db_expr_t ins;
159
160 ins = db_get_value(pc, sizeof(int), false);
161 if (!inst_trap_return(ins) &&
162 (!inst_return(ins) || --db_call_depth != 0)) {
163 if (db_sstep_print) {
164 if (inst_call(ins) || inst_return(ins)) {
165 int i;
166
167 db_printf("[after %6d] ", db_inst_count);
168 for (i = db_call_depth; --i > 0; )
169 db_printf(" ");
170 db_print_loc_and_inst(pc);
171 }
172 }
173 if (inst_call(ins))
174 db_call_depth++;
175 return (false); /* continue */
176 }
177 }
178 if (db_run_mode == STEP_CALLT) {
179 /* continue until call or return */
180 db_expr_t ins;
181
182 ins = db_get_value(pc, sizeof(int), false);
183 if (!inst_call(ins) &&
184 !inst_return(ins) &&
185 !inst_trap_return(ins)) {
186 return (false); /* continue */
187 }
188 }
189 return (true);
190 }
191
192 void
db_restart_at_pc(bool watchpt)193 db_restart_at_pc(bool watchpt)
194 {
195 db_addr_t pc = PC_REGS();
196
197 if ((db_run_mode == STEP_COUNT) ||
198 ((db_run_mode == STEP_ONCE) && db_sstep_multiple) ||
199 (db_run_mode == STEP_RETURN) ||
200 (db_run_mode == STEP_CALLT)) {
201 /*
202 * We are about to execute this instruction,
203 * so count it now.
204 */
205 db_get_value(pc, sizeof(int), false);
206 db_inst_count++;
207 db_load_count += inst_load(ins);
208 db_store_count += inst_store(ins);
209 }
210
211 if (db_run_mode == STEP_CONTINUE) {
212 if (watchpt || db_find_breakpoint_here(pc)) {
213 /*
214 * Step over breakpoint/watchpoint.
215 */
216 db_run_mode = STEP_INVISIBLE;
217 db_set_single_step();
218 } else {
219 db_set_breakpoints();
220 db_set_watchpoints();
221 }
222 } else {
223 db_set_single_step();
224 }
225 }
226
227 /* single-step */
228 /*ARGSUSED*/
229 void
db_single_step_cmd(db_expr_t addr,bool have_addr,db_expr_t count,char * modif)230 db_single_step_cmd(db_expr_t addr, bool have_addr, db_expr_t count, char *modif)
231 {
232 bool print = false;
233
234 if (count == -1)
235 count = 1;
236
237 if (modif[0] == 'p')
238 print = true;
239
240 db_run_mode = STEP_ONCE;
241 db_loop_count = count;
242 db_sstep_multiple = (count != 1);
243 db_sstep_print = print;
244 db_inst_count = 0;
245 db_load_count = 0;
246 db_store_count = 0;
247
248 db_cmd_loop_done = 1;
249 }
250
251 /* trace and print until call/return */
252 /*ARGSUSED*/
253 void
db_trace_until_call_cmd(db_expr_t addr,bool have_addr,db_expr_t count,char * modif)254 db_trace_until_call_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
255 char *modif)
256 {
257 bool print = false;
258
259 if (modif[0] == 'p')
260 print = true;
261
262 db_run_mode = STEP_CALLT;
263 db_sstep_print = print;
264 db_inst_count = 0;
265 db_load_count = 0;
266 db_store_count = 0;
267
268 db_cmd_loop_done = 1;
269 }
270
271 /*ARGSUSED*/
272 void
db_trace_until_matching_cmd(db_expr_t addr,bool have_addr,db_expr_t count,char * modif)273 db_trace_until_matching_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
274 char *modif)
275 {
276 bool print = false;
277
278 if (modif[0] == 'p')
279 print = true;
280
281 db_run_mode = STEP_RETURN;
282 db_call_depth = 1;
283 db_sstep_print = print;
284 db_inst_count = 0;
285 db_load_count = 0;
286 db_store_count = 0;
287
288 db_cmd_loop_done = 1;
289 }
290
291 /* continue */
292 /*ARGSUSED*/
293 void
db_continue_cmd(db_expr_t addr,bool have_addr,db_expr_t count,char * modif)294 db_continue_cmd(db_expr_t addr, bool have_addr, db_expr_t count, char *modif)
295 {
296 if (modif[0] == 'c')
297 db_run_mode = STEP_COUNT;
298 else
299 db_run_mode = STEP_CONTINUE;
300 db_inst_count = 0;
301 db_load_count = 0;
302 db_store_count = 0;
303
304 db_cmd_loop_done = 1;
305 }
306