FreeBSD/Linux Kernel Cross Reference
sys/ddb/db_run.c
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 __FBSDID("$FreeBSD$");
39
40 #include <sys/param.h>
41 #include <sys/kdb.h>
42 #include <sys/proc.h>
43 #include <sys/reg.h>
44 #include <sys/systm.h>
45
46 #include <machine/kdb.h>
47 #include <machine/pcb.h>
48
49 #include <vm/vm.h>
50
51 #include <ddb/ddb.h>
52 #include <ddb/db_access.h>
53 #include <ddb/db_break.h>
54 #include <ddb/db_command.h>
55
56 #define STEP_ONCE 1
57 #define STEP_RETURN 2
58 #define STEP_CALLT 3
59 #define STEP_CONTINUE 4
60 #define STEP_INVISIBLE 5
61 #define STEP_COUNT 6
62 static int db_run_mode = STEP_CONTINUE;
63
64 static bool db_sstep_multiple;
65 static bool db_sstep_print;
66 static int db_loop_count;
67 static int db_call_depth;
68
69 int db_inst_count;
70 int db_load_count;
71 int db_store_count;
72
73 bool
74 db_stop_at_pc(int type, int code, bool *is_breakpoint, bool *is_watchpoint)
75 {
76 db_addr_t pc;
77 db_breakpoint_t bkpt;
78
79 *is_breakpoint = IS_BREAKPOINT_TRAP(type, code);
80 *is_watchpoint = IS_WATCHPOINT_TRAP(type, code);
81 pc = PC_REGS();
82
83 db_clear_single_step();
84 db_clear_breakpoints();
85 db_clear_watchpoints();
86
87 #ifdef FIXUP_PC_AFTER_BREAK
88 if (*is_breakpoint) {
89 /*
90 * Breakpoint trap. Fix up the PC if the
91 * machine requires it.
92 */
93 FIXUP_PC_AFTER_BREAK
94 pc = PC_REGS();
95 }
96 #endif
97
98 /*
99 * Now check for a breakpoint at this address.
100 */
101 bkpt = db_find_breakpoint_here(pc);
102 if (bkpt) {
103 if (--bkpt->count == 0) {
104 bkpt->count = bkpt->init_count;
105 *is_breakpoint = true;
106 return (true); /* stop here */
107 }
108 return (false); /* continue the countdown */
109 } else if (*is_breakpoint) {
110 #ifdef BKPT_SKIP
111 BKPT_SKIP;
112 #endif
113 }
114
115 *is_breakpoint = false; /* might be a breakpoint, but not ours */
116
117 /*
118 * If not stepping, then silently ignore single-step traps
119 * (except for clearing the single-step-flag above).
120 *
121 * If stepping, then abort if the trap type is unexpected.
122 * Breakpoints owned by us are expected and were handled above.
123 * Single-steps are expected and are handled below. All others
124 * are unexpected.
125 *
126 * Only do either of these if the MD layer claims to classify
127 * single-step traps unambiguously (by defining IS_SSTEP_TRAP).
128 * Otherwise, fall through to the bad historical behaviour
129 * given by turning unexpected traps into expected traps: if not
130 * stepping, then expect only breakpoints and stop, and if
131 * stepping, then expect only single-steps and step.
132 */
133 #ifdef IS_SSTEP_TRAP
134 if (db_run_mode == STEP_CONTINUE && IS_SSTEP_TRAP(type, code))
135 return (false);
136 if (db_run_mode != STEP_CONTINUE && !IS_SSTEP_TRAP(type, code)) {
137 printf("Stepping aborted\n");
138 return (true);
139 }
140 #endif
141
142 if (db_run_mode == STEP_INVISIBLE) {
143 db_run_mode = STEP_CONTINUE;
144 return (false); /* continue */
145 }
146 if (db_run_mode == STEP_COUNT) {
147 return (false); /* continue */
148 }
149 if (db_run_mode == STEP_ONCE) {
150 if (--db_loop_count > 0) {
151 if (db_sstep_print) {
152 db_printf("\t\t");
153 db_print_loc_and_inst(pc);
154 }
155 return (false); /* continue */
156 }
157 }
158 if (db_run_mode == STEP_RETURN) {
159 /* continue until matching return */
160 db_expr_t ins;
161
162 ins = db_get_value(pc, sizeof(int), false);
163 if (!inst_trap_return(ins) &&
164 (!inst_return(ins) || --db_call_depth != 0)) {
165 if (db_sstep_print) {
166 if (inst_call(ins) || inst_return(ins)) {
167 int i;
168
169 db_printf("[after %6d] ", db_inst_count);
170 for (i = db_call_depth; --i > 0; )
171 db_printf(" ");
172 db_print_loc_and_inst(pc);
173 }
174 }
175 if (inst_call(ins))
176 db_call_depth++;
177 return (false); /* continue */
178 }
179 }
180 if (db_run_mode == STEP_CALLT) {
181 /* continue until call or return */
182 db_expr_t ins;
183
184 ins = db_get_value(pc, sizeof(int), false);
185 if (!inst_call(ins) &&
186 !inst_return(ins) &&
187 !inst_trap_return(ins)) {
188 return (false); /* continue */
189 }
190 }
191 return (true);
192 }
193
194 void
195 db_restart_at_pc(bool watchpt)
196 {
197 db_addr_t pc = PC_REGS();
198
199 if ((db_run_mode == STEP_COUNT) ||
200 ((db_run_mode == STEP_ONCE) && db_sstep_multiple) ||
201 (db_run_mode == STEP_RETURN) ||
202 (db_run_mode == STEP_CALLT)) {
203 /*
204 * We are about to execute this instruction,
205 * so count it now.
206 */
207 db_get_value(pc, sizeof(int), false);
208 db_inst_count++;
209 db_load_count += inst_load(ins);
210 db_store_count += inst_store(ins);
211 }
212
213 if (db_run_mode == STEP_CONTINUE) {
214 if (watchpt || db_find_breakpoint_here(pc)) {
215 /*
216 * Step over breakpoint/watchpoint.
217 */
218 db_run_mode = STEP_INVISIBLE;
219 db_set_single_step();
220 } else {
221 db_set_breakpoints();
222 db_set_watchpoints();
223 }
224 } else {
225 db_set_single_step();
226 }
227 }
228
229 /* single-step */
230 /*ARGSUSED*/
231 void
232 db_single_step_cmd(db_expr_t addr, bool have_addr, db_expr_t count, char *modif)
233 {
234 bool print = false;
235
236 if (count == -1)
237 count = 1;
238
239 if (modif[0] == 'p')
240 print = true;
241
242 db_run_mode = STEP_ONCE;
243 db_loop_count = count;
244 db_sstep_multiple = (count != 1);
245 db_sstep_print = print;
246 db_inst_count = 0;
247 db_load_count = 0;
248 db_store_count = 0;
249
250 db_cmd_loop_done = 1;
251 }
252
253 /* trace and print until call/return */
254 /*ARGSUSED*/
255 void
256 db_trace_until_call_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
257 char *modif)
258 {
259 bool print = false;
260
261 if (modif[0] == 'p')
262 print = true;
263
264 db_run_mode = STEP_CALLT;
265 db_sstep_print = print;
266 db_inst_count = 0;
267 db_load_count = 0;
268 db_store_count = 0;
269
270 db_cmd_loop_done = 1;
271 }
272
273 /*ARGSUSED*/
274 void
275 db_trace_until_matching_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
276 char *modif)
277 {
278 bool print = false;
279
280 if (modif[0] == 'p')
281 print = true;
282
283 db_run_mode = STEP_RETURN;
284 db_call_depth = 1;
285 db_sstep_print = print;
286 db_inst_count = 0;
287 db_load_count = 0;
288 db_store_count = 0;
289
290 db_cmd_loop_done = 1;
291 }
292
293 /* continue */
294 /*ARGSUSED*/
295 void
296 db_continue_cmd(db_expr_t addr, bool have_addr, db_expr_t count, char *modif)
297 {
298 if (modif[0] == 'c')
299 db_run_mode = STEP_COUNT;
300 else
301 db_run_mode = STEP_CONTINUE;
302 db_inst_count = 0;
303 db_load_count = 0;
304 db_store_count = 0;
305
306 db_cmd_loop_done = 1;
307 }
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