db_run.c revision 116176 
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: head/sys/ddb/db_run.c 116176 2003-06-10 22:09:23Z obrien $");
37
38#include <sys/param.h>
39
40#include <vm/vm.h>
41
42#include <ddb/ddb.h>
43#include <ddb/db_break.h>
44#include <ddb/db_access.h>
45
46static int	db_run_mode;
47#define	STEP_NONE	0
48#define	STEP_ONCE	1
49#define	STEP_RETURN	2
50#define	STEP_CALLT	3
51#define	STEP_CONTINUE	4
52#define STEP_INVISIBLE	5
53#define	STEP_COUNT	6
54
55static boolean_t	db_sstep_print;
56static int		db_loop_count;
57static int		db_call_depth;
58
59int		db_inst_count;
60int		db_load_count;
61int		db_store_count;
62
63#ifndef db_set_single_step
64extern void	db_set_single_step(db_regs_t *regs);
65#endif
66#ifndef db_clear_single_step
67extern void	db_clear_single_step(db_regs_t *regs);
68#endif
69
70#ifdef notused
71static void	db_single_step(db_regs_t *regs);
72#endif
73
74boolean_t
75db_stop_at_pc(is_breakpoint)
76	boolean_t	*is_breakpoint;
77{
78	register db_addr_t	pc;
79	register db_breakpoint_t bkpt;
80
81	db_clear_single_step(DDB_REGS);
82	db_clear_breakpoints();
83	db_clear_watchpoints();
84	pc = PC_REGS(DDB_REGS);
85
86#ifdef	FIXUP_PC_AFTER_BREAK
87	if (*is_breakpoint) {
88	    /*
89	     * Breakpoint trap.  Fix up the PC if the
90	     * machine requires it.
91	     */
92	    FIXUP_PC_AFTER_BREAK
93	    pc = PC_REGS(DDB_REGS);
94	}
95#endif
96
97	/*
98	 * Now check for a breakpoint at this address.
99	 */
100	bkpt = db_find_breakpoint_here(pc);
101	if (bkpt) {
102	    if (--bkpt->count == 0) {
103		bkpt->count = bkpt->init_count;
104		*is_breakpoint = TRUE;
105		return (TRUE);	/* stop here */
106	    }
107	} else if (*is_breakpoint) {
108#ifdef BKPT_SKIP
109		BKPT_SKIP;
110#endif
111	}
112
113	*is_breakpoint = FALSE;
114
115	if (db_run_mode == STEP_INVISIBLE) {
116	    db_run_mode = STEP_CONTINUE;
117	    return (FALSE);	/* continue */
118	}
119	if (db_run_mode == STEP_COUNT) {
120	    return (FALSE); /* continue */
121	}
122	if (db_run_mode == STEP_ONCE) {
123	    if (--db_loop_count > 0) {
124		if (db_sstep_print) {
125		    db_printf("\t\t");
126		    db_print_loc_and_inst(pc);
127		    db_printf("\n");
128		}
129		return (FALSE);	/* continue */
130	    }
131	}
132	if (db_run_mode == STEP_RETURN) {
133	    /* continue until matching return */
134	    db_expr_t ins;
135
136	    ins = db_get_value(pc, sizeof(int), FALSE);
137	    if (!inst_trap_return(ins) &&
138		(!inst_return(ins) || --db_call_depth != 0)) {
139		if (db_sstep_print) {
140		    if (inst_call(ins) || inst_return(ins)) {
141			register int i;
142
143			db_printf("[after %6d]     ", db_inst_count);
144			for (i = db_call_depth; --i > 0; )
145			    db_printf("  ");
146			db_print_loc_and_inst(pc);
147			db_printf("\n");
148		    }
149		}
150		if (inst_call(ins))
151		    db_call_depth++;
152		return (FALSE);	/* continue */
153	    }
154	}
155	if (db_run_mode == STEP_CALLT) {
156	    /* continue until call or return */
157	    db_expr_t ins;
158
159	    ins = db_get_value(pc, sizeof(int), FALSE);
160	    if (!inst_call(ins) &&
161		!inst_return(ins) &&
162		!inst_trap_return(ins)) {
163		return (FALSE);	/* continue */
164	    }
165	}
166	db_run_mode = STEP_NONE;
167	return (TRUE);
168}
169
170void
171db_restart_at_pc(watchpt)
172	boolean_t watchpt;
173{
174	register db_addr_t	pc = PC_REGS(DDB_REGS);
175
176	if ((db_run_mode == STEP_COUNT) ||
177	    (db_run_mode == STEP_RETURN) ||
178	    (db_run_mode == STEP_CALLT)) {
179	    db_expr_t		ins;
180
181	    /*
182	     * We are about to execute this instruction,
183	     * so count it now.
184	     */
185
186	    ins = db_get_value(pc, sizeof(int), FALSE);
187	    db_inst_count++;
188	    db_load_count += inst_load(ins);
189	    db_store_count += inst_store(ins);
190#ifdef	SOFTWARE_SSTEP
191	    /* XXX works on mips, but... */
192	    if (inst_branch(ins) || inst_call(ins)) {
193		ins = db_get_value(next_instr_address(pc,1),
194				   sizeof(int), FALSE);
195		db_inst_count++;
196		db_load_count += inst_load(ins);
197		db_store_count += inst_store(ins);
198	    }
199#endif	/* SOFTWARE_SSTEP */
200	}
201
202	if (db_run_mode == STEP_CONTINUE) {
203	    if (watchpt || db_find_breakpoint_here(pc)) {
204		/*
205		 * Step over breakpoint/watchpoint.
206		 */
207		db_run_mode = STEP_INVISIBLE;
208		db_set_single_step(DDB_REGS);
209	    } else {
210		db_set_breakpoints();
211		db_set_watchpoints();
212	    }
213	} else {
214	    db_set_single_step(DDB_REGS);
215	}
216}
217
218#ifdef notused
219static void
220db_single_step(regs)
221	db_regs_t *regs;
222{
223	if (db_run_mode == STEP_CONTINUE) {
224	    db_run_mode = STEP_INVISIBLE;
225	    db_set_single_step(regs);
226	}
227}
228#endif
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 */
260db_breakpoint_t	db_not_taken_bkpt = 0;
261db_breakpoint_t	db_taken_bkpt = 0;
262
263void
264db_set_single_step(regs)
265	register db_regs_t *regs;
266{
267	db_addr_t pc = PC_REGS(regs), brpc;
268	 unsigned	 inst;
269
270	/*
271	 *	User was stopped at pc, e.g. the instruction
272	 *	at pc was not executed.
273	 */
274	inst = db_get_value(pc, sizeof(int), FALSE);
275	if (inst_branch(inst) || inst_call(inst)) {
276	    brpc = branch_taken(inst, pc, regs);
277	    if (brpc != pc) {	/* self-branches are hopeless */
278		db_taken_bkpt = db_set_temp_breakpoint(brpc);
279	    }
280	    pc = next_instr_address(pc,1);
281	}
282	pc = next_instr_address(pc,0);
283	db_not_taken_bkpt = db_set_temp_breakpoint(pc);
284}
285
286void
287db_clear_single_step(regs)
288	db_regs_t *regs;
289{
290
291	if (db_not_taken_bkpt != 0) {
292	    db_delete_temp_breakpoint(db_not_taken_bkpt);
293	    db_not_taken_bkpt = 0;
294	}
295	if (db_taken_bkpt != 0) {
296	    db_delete_temp_breakpoint(db_taken_bkpt);
297	    db_taken_bkpt = 0;
298	}
299}
300
301#endif	/* SOFTWARE_SSTEP */
302
303extern int	db_cmd_loop_done;
304
305/* single-step */
306/*ARGSUSED*/
307void
308db_single_step_cmd(addr, have_addr, count, modif)
309	db_expr_t	addr;
310	boolean_t	have_addr;
311	db_expr_t	count;
312	char *		modif;
313{
314	boolean_t	print = FALSE;
315
316	if (count == -1)
317	    count = 1;
318
319	if (modif[0] == 'p')
320	    print = TRUE;
321
322	db_run_mode = STEP_ONCE;
323	db_loop_count = count;
324	db_sstep_print = print;
325	db_inst_count = 0;
326	db_load_count = 0;
327	db_store_count = 0;
328
329	db_cmd_loop_done = 1;
330}
331
332/* trace and print until call/return */
333/*ARGSUSED*/
334void
335db_trace_until_call_cmd(addr, have_addr, count, modif)
336	db_expr_t	addr;
337	boolean_t	have_addr;
338	db_expr_t	count;
339	char *		modif;
340{
341	boolean_t	print = FALSE;
342
343	if (modif[0] == 'p')
344	    print = TRUE;
345
346	db_run_mode = STEP_CALLT;
347	db_sstep_print = print;
348	db_inst_count = 0;
349	db_load_count = 0;
350	db_store_count = 0;
351
352	db_cmd_loop_done = 1;
353}
354
355/*ARGSUSED*/
356void
357db_trace_until_matching_cmd(addr, have_addr, count, modif)
358	db_expr_t	addr;
359	boolean_t	have_addr;
360	db_expr_t	count;
361	char *		modif;
362{
363	boolean_t	print = FALSE;
364
365	if (modif[0] == 'p')
366	    print = TRUE;
367
368	db_run_mode = STEP_RETURN;
369	db_call_depth = 1;
370	db_sstep_print = print;
371	db_inst_count = 0;
372	db_load_count = 0;
373	db_store_count = 0;
374
375	db_cmd_loop_done = 1;
376}
377
378/* continue */
379/*ARGSUSED*/
380void
381db_continue_cmd(addr, have_addr, count, modif)
382	db_expr_t	addr;
383	boolean_t	have_addr;
384	db_expr_t	count;
385	char *		modif;
386{
387	if (modif[0] == 'c')
388	    db_run_mode = STEP_COUNT;
389	else
390	    db_run_mode = STEP_CONTINUE;
391	db_inst_count = 0;
392	db_load_count = 0;
393	db_store_count = 0;
394
395	db_cmd_loop_done = 1;
396}
397