1 /*
2 * Mach Operating System
3 * Copyright (c) 1991,1990 Carnegie Mellon University
4 * All Rights Reserved.
5 *
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.
11 *
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.
15 *
16 * Carnegie Mellon requests users of this software to return to
17 *
18 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
19 * School of Computer Science
20 * Carnegie Mellon University
21 * Pittsburgh PA 15213-3890
22 *
23 * any improvements or extensions that they make and grant Carnegie the
24 * rights to redistribute these changes.
25 *
26 * $FreeBSD: src/sys/ddb/db_run.c,v 1.18 1999/08/28 00:41:10 peter Exp $
27 */
28
29 /*
30 * Author: David B. Golub, Carnegie Mellon University
31 * Date: 7/90
32 */
33
34 /*
35 * Commands to run process.
36 */
37 #include <sys/param.h>
38
39 #include <vm/vm.h>
40
41 #include <ddb/ddb.h>
42 #include <ddb/db_break.h>
43 #include <ddb/db_access.h>
44
45 static int db_run_mode;
46 #define STEP_NONE 0
47 #define STEP_ONCE 1
48 #define STEP_RETURN 2
49 #define STEP_CALLT 3
50 #define STEP_CONTINUE 4
51 #define STEP_INVISIBLE 5
52 #define STEP_COUNT 6
53
54 static boolean_t db_sstep_print;
55 static int db_loop_count;
56 static int db_call_depth;
57
58 int db_inst_count;
59 int db_load_count;
60 int db_store_count;
61
62 #ifndef db_set_single_step
63 extern void db_set_single_step (db_regs_t *regs);
64 #endif
65 #ifndef db_clear_single_step
66 extern void db_clear_single_step (db_regs_t *regs);
67 #endif
68
69 #ifdef notused
70 static void db_single_step (db_regs_t *regs);
71 #endif
72
73 boolean_t
db_stop_at_pc(boolean_t * is_breakpoint)74 db_stop_at_pc(boolean_t *is_breakpoint)
75 {
76 db_addr_t pc;
77 db_breakpoint_t bkpt;
78
79 db_clear_single_step(DDB_REGS);
80 db_clear_breakpoints();
81 db_clear_watchpoints();
82 pc = PC_REGS(DDB_REGS);
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(DDB_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 } else if (*is_breakpoint) {
106 #ifdef __x86_64__
107 ddb_regs.tf_rip += 1;
108 #endif
109 }
110
111 *is_breakpoint = FALSE;
112
113 if (db_run_mode == STEP_INVISIBLE) {
114 db_run_mode = STEP_CONTINUE;
115 return (FALSE); /* continue */
116 }
117 if (db_run_mode == STEP_COUNT) {
118 return (FALSE); /* continue */
119 }
120 if (db_run_mode == STEP_ONCE) {
121 if (--db_loop_count > 0) {
122 if (db_sstep_print) {
123 db_printf("\t\t");
124 db_print_loc_and_inst(pc, DDB_REGS);
125 db_printf("\n");
126 }
127 return (FALSE); /* continue */
128 }
129 }
130 if (db_run_mode == STEP_RETURN) {
131 db_expr_t ins = db_get_value(pc, sizeof(int), FALSE);
132
133 /* continue until matching return */
134
135 if (!inst_trap_return(ins) &&
136 (!inst_return(ins) || --db_call_depth != 0)) {
137 if (db_sstep_print) {
138 if (inst_call(ins) || inst_return(ins)) {
139 int i;
140
141 db_printf("[after %6d] ", db_inst_count);
142 for (i = db_call_depth; --i > 0; )
143 db_printf(" ");
144 db_print_loc_and_inst(pc, DDB_REGS);
145 db_printf("\n");
146 }
147 }
148 if (inst_call(ins))
149 db_call_depth++;
150 return (FALSE); /* continue */
151 }
152 }
153 if (db_run_mode == STEP_CALLT) {
154 db_expr_t ins = db_get_value(pc, sizeof(int), FALSE);
155
156 /* continue until call or return */
157
158 if (!inst_call(ins) &&
159 !inst_return(ins) &&
160 !inst_trap_return(ins)) {
161 return (FALSE); /* continue */
162 }
163 }
164 db_run_mode = STEP_NONE;
165 return (TRUE);
166 }
167
168 void
db_restart_at_pc(boolean_t watchpt)169 db_restart_at_pc(boolean_t watchpt)
170 {
171 db_addr_t pc = PC_REGS(DDB_REGS);
172
173 if ((db_run_mode == STEP_COUNT) ||
174 (db_run_mode == STEP_RETURN) ||
175 (db_run_mode == STEP_CALLT)) {
176 db_expr_t ins __unused; /* seems used but gcc thinks not */
177
178 /*
179 * We are about to execute this instruction,
180 * so count it now.
181 */
182
183 ins = db_get_value(pc, sizeof(int), FALSE);
184 db_inst_count++;
185 db_load_count += inst_load(ins);
186 db_store_count += inst_store(ins);
187 #ifdef SOFTWARE_SSTEP
188 /* XXX works on mips, but... */
189 if (inst_branch(ins) || inst_call(ins)) {
190 ins = db_get_value(next_instr_address(pc,1),
191 sizeof(int), FALSE);
192 db_inst_count++;
193 db_load_count += inst_load(ins);
194 db_store_count += inst_store(ins);
195 }
196 #endif /* SOFTWARE_SSTEP */
197 }
198
199 if (db_run_mode == STEP_CONTINUE) {
200 if (watchpt || db_find_breakpoint_here(pc)) {
201 /*
202 * Step over breakpoint/watchpoint.
203 */
204 db_run_mode = STEP_INVISIBLE;
205 db_set_single_step(DDB_REGS);
206 } else {
207 db_set_breakpoints();
208 db_set_watchpoints();
209 }
210 } else {
211 db_set_single_step(DDB_REGS);
212 }
213 }
214
215 #ifdef notused
216 static void
db_single_step(db_regs_t * regs)217 db_single_step(db_regs_t *regs)
218 {
219 if (db_run_mode == STEP_CONTINUE) {
220 db_run_mode = STEP_INVISIBLE;
221 db_set_single_step(regs);
222 }
223 }
224 #endif
225
226 #ifdef SOFTWARE_SSTEP
227 /*
228 * Software implementation of single-stepping.
229 * If your machine does not have a trace mode
230 * similar to the vax or sun ones you can use
231 * this implementation, done for the mips.
232 * Just define the above conditional and provide
233 * the functions/macros defined below.
234 *
235 * extern boolean_t
236 * inst_branch(), returns true if the instruction might branch
237 * extern unsigned
238 * branch_taken(), return the address the instruction might
239 * branch to
240 * db_getreg_val(); return the value of a user register,
241 * as indicated in the hardware instruction
242 * encoding, e.g. 8 for r8
243 *
244 * next_instr_address(pc,bd) returns the address of the first
245 * instruction following the one at "pc",
246 * which is either in the taken path of
247 * the branch (bd==1) or not. This is
248 * for machines (mips) with branch delays.
249 *
250 * A single-step may involve at most 2 breakpoints -
251 * one for branch-not-taken and one for branch taken.
252 * If one of these addresses does not already have a breakpoint,
253 * we allocate a breakpoint and save it here.
254 * These breakpoints are deleted on return.
255 */
256 db_breakpoint_t db_not_taken_bkpt = 0;
257 db_breakpoint_t db_taken_bkpt = 0;
258
259 void
db_set_single_step(db_regs_t * regs)260 db_set_single_step(db_regs_t *regs)
261 {
262 db_addr_t pc = PC_REGS(regs), brpc;
263 unsigned inst;
264
265 /*
266 * User was stopped at pc, e.g. the instruction
267 * at pc was not executed.
268 */
269 inst = db_get_value(pc, sizeof(int), FALSE);
270 if (inst_branch(inst) || inst_call(inst)) {
271 brpc = branch_taken(inst, pc, regs);
272 if (brpc != pc) { /* self-branches are hopeless */
273 db_taken_bkpt = db_set_temp_breakpoint(brpc);
274 }
275 pc = next_instr_address(pc,1);
276 }
277 pc = next_instr_address(pc,0);
278 db_not_taken_bkpt = db_set_temp_breakpoint(pc);
279 }
280
281 void
db_clear_single_step(db_regs_t * regs)282 db_clear_single_step(db_regs_t *regs)
283 {
284
285 if (db_not_taken_bkpt != 0) {
286 db_delete_temp_breakpoint(db_not_taken_bkpt);
287 db_not_taken_bkpt = 0;
288 }
289 if (db_taken_bkpt != 0) {
290 db_delete_temp_breakpoint(db_taken_bkpt);
291 db_taken_bkpt = 0;
292 }
293 }
294
295 #endif /* SOFTWARE_SSTEP */
296
297 extern boolean_t db_cmd_loop_done;
298
299 /* single-step */
300 /*ARGSUSED*/
301 void
db_single_step_cmd(db_expr_t addr,boolean_t have_addr,db_expr_t count,char * modif)302 db_single_step_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
303 char *modif)
304 {
305 boolean_t print = FALSE;
306
307 if (count == -1)
308 count = 1;
309
310 if (modif[0] == 'p')
311 print = TRUE;
312
313 db_run_mode = STEP_ONCE;
314 db_loop_count = count;
315 db_sstep_print = print;
316 db_inst_count = 0;
317 db_load_count = 0;
318 db_store_count = 0;
319
320 db_cmd_loop_done = TRUE;
321 }
322
323 /* trace and print until call/return */
324 /*ARGSUSED*/
325 void
db_trace_until_call_cmd(db_expr_t addr,boolean_t have_addr,db_expr_t count,char * modif)326 db_trace_until_call_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
327 char *modif)
328 {
329 boolean_t print = FALSE;
330
331 if (modif[0] == 'p')
332 print = TRUE;
333
334 db_run_mode = STEP_CALLT;
335 db_sstep_print = print;
336 db_inst_count = 0;
337 db_load_count = 0;
338 db_store_count = 0;
339
340 db_cmd_loop_done = TRUE;
341 }
342
343 /*ARGSUSED*/
344 void
db_trace_until_matching_cmd(db_expr_t addr,boolean_t have_addr,db_expr_t count,char * modif)345 db_trace_until_matching_cmd(db_expr_t addr, boolean_t have_addr,
346 db_expr_t count, char *modif)
347 {
348 boolean_t print = FALSE;
349
350 if (modif[0] == 'p')
351 print = TRUE;
352
353 db_run_mode = STEP_RETURN;
354 db_call_depth = 1;
355 db_sstep_print = print;
356 db_inst_count = 0;
357 db_load_count = 0;
358 db_store_count = 0;
359
360 db_cmd_loop_done = TRUE;
361 }
362
363 /* continue */
364 /*ARGSUSED*/
365 void
db_continue_cmd(db_expr_t addr,boolean_t have_addr,db_expr_t count,char * modif)366 db_continue_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
367 char *modif)
368 {
369 if (modif[0] == 'c')
370 db_run_mode = STEP_COUNT;
371 else
372 db_run_mode = STEP_CONTINUE;
373 db_inst_count = 0;
374 db_load_count = 0;
375 db_store_count = 0;
376
377 db_cmd_loop_done = TRUE;
378 }
379