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