FreeBSD/Linux Kernel Cross Reference
sys/ddb/db_run.c
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 /*
27 * Author: David B. Golub, Carnegie Mellon University
28 * Date: 7/90
29 */
30
31 /*
32 * Commands to run process.
33 */
34
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD: src/sys/ddb/db_run.c,v 1.28 2008/08/02 12:49:43 cognet Exp $");
37
38 #include <sys/param.h>
39 #include <sys/kdb.h>
40 #include <sys/proc.h>
41
42 #include <machine/kdb.h>
43 #include <machine/pcb.h>
44
45 #include <vm/vm.h>
46
47 #include <ddb/ddb.h>
48 #include <ddb/db_break.h>
49 #include <ddb/db_access.h>
50
51 static int db_run_mode;
52 #define STEP_NONE 0
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
60 static boolean_t db_sstep_print;
61 static int db_loop_count;
62 static int db_call_depth;
63
64 int db_inst_count;
65 int db_load_count;
66 int db_store_count;
67
68 #ifndef db_set_single_step
69 void db_set_single_step(void);
70 #endif
71 #ifndef db_clear_single_step
72 void db_clear_single_step(void);
73 #endif
74
75 #ifdef SOFTWARE_SSTEP
76 db_breakpoint_t db_not_taken_bkpt = 0;
77 db_breakpoint_t db_taken_bkpt = 0;
78 #endif
79
80 boolean_t
81 db_stop_at_pc(is_breakpoint)
82 boolean_t *is_breakpoint;
83 {
84 register db_addr_t pc;
85 register db_breakpoint_t bkpt;
86
87 pc = PC_REGS();
88 #ifdef SOFTWARE_SSTEP
89 if ((db_not_taken_bkpt != 0 && pc == db_not_taken_bkpt->address)
90 || (db_taken_bkpt != 0 && pc == db_taken_bkpt->address))
91 *is_breakpoint = FALSE;
92 #endif
93
94 db_clear_single_step();
95 db_clear_breakpoints();
96 db_clear_watchpoints();
97
98 #ifdef FIXUP_PC_AFTER_BREAK
99 if (*is_breakpoint) {
100 /*
101 * Breakpoint trap. Fix up the PC if the
102 * machine requires it.
103 */
104 FIXUP_PC_AFTER_BREAK
105 pc = PC_REGS();
106 }
107 #endif
108
109 /*
110 * Now check for a breakpoint at this address.
111 */
112 bkpt = db_find_breakpoint_here(pc);
113 if (bkpt) {
114 if (--bkpt->count == 0) {
115 bkpt->count = bkpt->init_count;
116 *is_breakpoint = TRUE;
117 return (TRUE); /* stop here */
118 }
119 } else if (*is_breakpoint) {
120 #ifdef BKPT_SKIP
121 BKPT_SKIP;
122 #endif
123 }
124
125 *is_breakpoint = FALSE;
126
127 if (db_run_mode == STEP_INVISIBLE) {
128 db_run_mode = STEP_CONTINUE;
129 return (FALSE); /* continue */
130 }
131 if (db_run_mode == STEP_COUNT) {
132 return (FALSE); /* continue */
133 }
134 if (db_run_mode == STEP_ONCE) {
135 if (--db_loop_count > 0) {
136 if (db_sstep_print) {
137 db_printf("\t\t");
138 db_print_loc_and_inst(pc);
139 db_printf("\n");
140 }
141 return (FALSE); /* continue */
142 }
143 }
144 if (db_run_mode == STEP_RETURN) {
145 /* continue until matching return */
146 db_expr_t ins;
147
148 ins = db_get_value(pc, sizeof(int), FALSE);
149 if (!inst_trap_return(ins) &&
150 (!inst_return(ins) || --db_call_depth != 0)) {
151 if (db_sstep_print) {
152 if (inst_call(ins) || inst_return(ins)) {
153 register int i;
154
155 db_printf("[after %6d] ", db_inst_count);
156 for (i = db_call_depth; --i > 0; )
157 db_printf(" ");
158 db_print_loc_and_inst(pc);
159 db_printf("\n");
160 }
161 }
162 if (inst_call(ins))
163 db_call_depth++;
164 return (FALSE); /* continue */
165 }
166 }
167 if (db_run_mode == STEP_CALLT) {
168 /* continue until call or return */
169 db_expr_t ins;
170
171 ins = db_get_value(pc, sizeof(int), FALSE);
172 if (!inst_call(ins) &&
173 !inst_return(ins) &&
174 !inst_trap_return(ins)) {
175 return (FALSE); /* continue */
176 }
177 }
178 db_run_mode = STEP_NONE;
179 return (TRUE);
180 }
181
182 void
183 db_restart_at_pc(watchpt)
184 boolean_t watchpt;
185 {
186 register db_addr_t pc = PC_REGS();
187
188 if ((db_run_mode == STEP_COUNT) ||
189 (db_run_mode == STEP_RETURN) ||
190 (db_run_mode == STEP_CALLT)) {
191 db_expr_t ins;
192
193 /*
194 * We are about to execute this instruction,
195 * so count it now.
196 */
197
198 ins = db_get_value(pc, sizeof(int), FALSE);
199 db_inst_count++;
200 db_load_count += inst_load(ins);
201 db_store_count += inst_store(ins);
202 #ifdef SOFTWARE_SSTEP
203 /* XXX works on mips, but... */
204 if (inst_branch(ins) || inst_call(ins)) {
205 ins = db_get_value(next_instr_address(pc,1),
206 sizeof(int), FALSE);
207 db_inst_count++;
208 db_load_count += inst_load(ins);
209 db_store_count += inst_store(ins);
210 }
211 #endif /* SOFTWARE_SSTEP */
212 }
213
214 if (db_run_mode == STEP_CONTINUE) {
215 if (watchpt || db_find_breakpoint_here(pc)) {
216 /*
217 * Step over breakpoint/watchpoint.
218 */
219 db_run_mode = STEP_INVISIBLE;
220 db_set_single_step();
221 } else {
222 db_set_breakpoints();
223 db_set_watchpoints();
224 }
225 } else {
226 db_set_single_step();
227 }
228 }
229
230 #ifdef SOFTWARE_SSTEP
231 /*
232 * Software implementation of single-stepping.
233 * If your machine does not have a trace mode
234 * similar to the vax or sun ones you can use
235 * this implementation, done for the mips.
236 * Just define the above conditional and provide
237 * the functions/macros defined below.
238 *
239 * extern boolean_t
240 * inst_branch(), returns true if the instruction might branch
241 * extern unsigned
242 * branch_taken(), return the address the instruction might
243 * branch to
244 * db_getreg_val(); return the value of a user register,
245 * as indicated in the hardware instruction
246 * encoding, e.g. 8 for r8
247 *
248 * next_instr_address(pc,bd) returns the address of the first
249 * instruction following the one at "pc",
250 * which is either in the taken path of
251 * the branch (bd==1) or not. This is
252 * for machines (mips) with branch delays.
253 *
254 * A single-step may involve at most 2 breakpoints -
255 * one for branch-not-taken and one for branch taken.
256 * If one of these addresses does not already have a breakpoint,
257 * we allocate a breakpoint and save it here.
258 * These breakpoints are deleted on return.
259 */
260
261 void
262 db_set_single_step(void)
263 {
264 db_addr_t pc = PC_REGS(), brpc;
265 unsigned inst;
266
267 /*
268 * User was stopped at pc, e.g. the instruction
269 * at pc was not executed.
270 */
271 inst = db_get_value(pc, sizeof(int), FALSE);
272 if (inst_branch(inst) || inst_call(inst) || inst_return(inst)) {
273 brpc = branch_taken(inst, pc);
274 if (brpc != pc) { /* self-branches are hopeless */
275 db_taken_bkpt = db_set_temp_breakpoint(brpc);
276 }
277 pc = next_instr_address(pc, 1);
278 }
279 pc = next_instr_address(pc, 0);
280 db_not_taken_bkpt = db_set_temp_breakpoint(pc);
281 }
282
283 void
284 db_clear_single_step(void)
285 {
286
287 if (db_not_taken_bkpt != 0) {
288 db_delete_temp_breakpoint(db_not_taken_bkpt);
289 db_not_taken_bkpt = 0;
290 }
291 if (db_taken_bkpt != 0) {
292 db_delete_temp_breakpoint(db_taken_bkpt);
293 db_taken_bkpt = 0;
294 }
295 }
296
297 #endif /* SOFTWARE_SSTEP */
298
299 extern int db_cmd_loop_done;
300
301 /* single-step */
302 /*ARGSUSED*/
303 void
304 db_single_step_cmd(addr, have_addr, count, modif)
305 db_expr_t addr;
306 boolean_t have_addr;
307 db_expr_t count;
308 char * modif;
309 {
310 boolean_t print = FALSE;
311
312 if (count == -1)
313 count = 1;
314
315 if (modif[0] == 'p')
316 print = TRUE;
317
318 db_run_mode = STEP_ONCE;
319 db_loop_count = count;
320 db_sstep_print = print;
321 db_inst_count = 0;
322 db_load_count = 0;
323 db_store_count = 0;
324
325 db_cmd_loop_done = 1;
326 }
327
328 /* trace and print until call/return */
329 /*ARGSUSED*/
330 void
331 db_trace_until_call_cmd(addr, have_addr, count, modif)
332 db_expr_t addr;
333 boolean_t have_addr;
334 db_expr_t count;
335 char * modif;
336 {
337 boolean_t print = FALSE;
338
339 if (modif[0] == 'p')
340 print = TRUE;
341
342 db_run_mode = STEP_CALLT;
343 db_sstep_print = print;
344 db_inst_count = 0;
345 db_load_count = 0;
346 db_store_count = 0;
347
348 db_cmd_loop_done = 1;
349 }
350
351 /*ARGSUSED*/
352 void
353 db_trace_until_matching_cmd(addr, have_addr, count, modif)
354 db_expr_t addr;
355 boolean_t have_addr;
356 db_expr_t count;
357 char * modif;
358 {
359 boolean_t print = FALSE;
360
361 if (modif[0] == 'p')
362 print = TRUE;
363
364 db_run_mode = STEP_RETURN;
365 db_call_depth = 1;
366 db_sstep_print = print;
367 db_inst_count = 0;
368 db_load_count = 0;
369 db_store_count = 0;
370
371 db_cmd_loop_done = 1;
372 }
373
374 /* continue */
375 /*ARGSUSED*/
376 void
377 db_continue_cmd(addr, have_addr, count, modif)
378 db_expr_t addr;
379 boolean_t have_addr;
380 db_expr_t count;
381 char * modif;
382 {
383 if (modif[0] == 'c')
384 db_run_mode = STEP_COUNT;
385 else
386 db_run_mode = STEP_CONTINUE;
387 db_inst_count = 0;
388 db_load_count = 0;
389 db_store_count = 0;
390
391 db_cmd_loop_done = 1;
392 }
393
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