db_run.c revision 98694 
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: head/sys/ddb/db_run.c 98694 2002-06-23 20:03:03Z mux $
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
45static 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
54static boolean_t	db_sstep_print;
55static int		db_loop_count;
56static int		db_call_depth;
57
58int		db_inst_count;
59int		db_load_count;
60int		db_store_count;
61
62#ifndef db_set_single_step
63extern void	db_set_single_step(db_regs_t *regs);
64#endif
65#ifndef db_clear_single_step
66extern void	db_clear_single_step(db_regs_t *regs);
67#endif
68
69#ifdef notused
70static void	db_single_step(db_regs_t *regs);
71#endif
72
73boolean_t
74db_stop_at_pc(is_breakpoint)
75	boolean_t	*is_breakpoint;
76{
77	register db_addr_t	pc;
78	register db_breakpoint_t bkpt;
79
80	db_clear_single_step(DDB_REGS);
81	db_clear_breakpoints();
82	db_clear_watchpoints();
83	pc = PC_REGS(DDB_REGS);
84
85#ifdef	FIXUP_PC_AFTER_BREAK
86	if (*is_breakpoint) {
87	    /*
88	     * Breakpoint trap.  Fix up the PC if the
89	     * machine requires it.
90	     */
91	    FIXUP_PC_AFTER_BREAK
92	    pc = PC_REGS(DDB_REGS);
93	}
94#endif
95
96	/*
97	 * Now check for a breakpoint at this address.
98	 */
99	bkpt = db_find_breakpoint_here(pc);
100	if (bkpt) {
101	    if (--bkpt->count == 0) {
102		bkpt->count = bkpt->init_count;
103		*is_breakpoint = TRUE;
104		return (TRUE);	/* stop here */
105	    }
106	} else if (*is_breakpoint) {
107#ifdef BKPT_SKIP
108		BKPT_SKIP;
109#endif
110	}
111
112	*is_breakpoint = FALSE;
113
114	if (db_run_mode == STEP_INVISIBLE) {
115	    db_run_mode = STEP_CONTINUE;
116	    return (FALSE);	/* continue */
117	}
118	if (db_run_mode == STEP_COUNT) {
119	    return (FALSE); /* continue */
120	}
121	if (db_run_mode == STEP_ONCE) {
122	    if (--db_loop_count > 0) {
123		if (db_sstep_print) {
124		    db_printf("\t\t");
125		    db_print_loc_and_inst(pc);
126		    db_printf("\n");
127		}
128		return (FALSE);	/* continue */
129	    }
130	}
131	if (db_run_mode == STEP_RETURN) {
132	    /* continue until matching return */
133	    db_expr_t ins;
134
135	    ins = db_get_value(pc, sizeof(int), FALSE);
136	    if (!inst_trap_return(ins) &&
137		(!inst_return(ins) || --db_call_depth != 0)) {
138		if (db_sstep_print) {
139		    if (inst_call(ins) || inst_return(ins)) {
140			register int i;
141
142			db_printf("[after %6d]     ", db_inst_count);
143			for (i = db_call_depth; --i > 0; )
144			    db_printf("  ");
145			db_print_loc_and_inst(pc);
146			db_printf("\n");
147		    }
148		}
149		if (inst_call(ins))
150		    db_call_depth++;
151		return (FALSE);	/* continue */
152	    }
153	}
154	if (db_run_mode == STEP_CALLT) {
155	    /* continue until call or return */
156	    db_expr_t ins;
157
158	    ins = db_get_value(pc, sizeof(int), FALSE);
159	    if (!inst_call(ins) &&
160		!inst_return(ins) &&
161		!inst_trap_return(ins)) {
162		return (FALSE);	/* continue */
163	    }
164	}
165	db_run_mode = STEP_NONE;
166	return (TRUE);
167}
168
169void
170db_restart_at_pc(watchpt)
171	boolean_t watchpt;
172{
173	register db_addr_t	pc = PC_REGS(DDB_REGS);
174
175	if ((db_run_mode == STEP_COUNT) ||
176	    (db_run_mode == STEP_RETURN) ||
177	    (db_run_mode == STEP_CALLT)) {
178	    db_expr_t		ins;
179
180	    /*
181	     * We are about to execute this instruction,
182	     * so count it now.
183	     */
184
185	    ins = db_get_value(pc, sizeof(int), FALSE);
186	    db_inst_count++;
187	    db_load_count += inst_load(ins);
188	    db_store_count += inst_store(ins);
189#ifdef	SOFTWARE_SSTEP
190	    /* XXX works on mips, but... */
191	    if (inst_branch(ins) || inst_call(ins)) {
192		ins = db_get_value(next_instr_address(pc,1),
193				   sizeof(int), FALSE);
194		db_inst_count++;
195		db_load_count += inst_load(ins);
196		db_store_count += inst_store(ins);
197	    }
198#endif	/* SOFTWARE_SSTEP */
199	}
200
201	if (db_run_mode == STEP_CONTINUE) {
202	    if (watchpt || db_find_breakpoint_here(pc)) {
203		/*
204		 * Step over breakpoint/watchpoint.
205		 */
206		db_run_mode = STEP_INVISIBLE;
207		db_set_single_step(DDB_REGS);
208	    } else {
209		db_set_breakpoints();
210		db_set_watchpoints();
211	    }
212	} else {
213	    db_set_single_step(DDB_REGS);
214	}
215}
216
217#ifdef notused
218static void
219db_single_step(regs)
220	db_regs_t *regs;
221{
222	if (db_run_mode == STEP_CONTINUE) {
223	    db_run_mode = STEP_INVISIBLE;
224	    db_set_single_step(regs);
225	}
226}
227#endif
228
229#ifdef	SOFTWARE_SSTEP
230/*
231 *	Software implementation of single-stepping.
232 *	If your machine does not have a trace mode
233 *	similar to the vax or sun ones you can use
234 *	this implementation, done for the mips.
235 *	Just define the above conditional and provide
236 *	the functions/macros defined below.
237 *
238 * extern boolean_t
239 *	inst_branch(),		returns true if the instruction might branch
240 * extern unsigned
241 *	branch_taken(),		return the address the instruction might
242 *				branch to
243 *	db_getreg_val();	return the value of a user register,
244 *				as indicated in the hardware instruction
245 *				encoding, e.g. 8 for r8
246 *
247 * next_instr_address(pc,bd)	returns the address of the first
248 *				instruction following the one at "pc",
249 *				which is either in the taken path of
250 *				the branch (bd==1) or not.  This is
251 *				for machines (mips) with branch delays.
252 *
253 *	A single-step may involve at most 2 breakpoints -
254 *	one for branch-not-taken and one for branch taken.
255 *	If one of these addresses does not already have a breakpoint,
256 *	we allocate a breakpoint and save it here.
257 *	These breakpoints are deleted on return.
258 */
259db_breakpoint_t	db_not_taken_bkpt = 0;
260db_breakpoint_t	db_taken_bkpt = 0;
261
262void
263db_set_single_step(regs)
264	register db_regs_t *regs;
265{
266	db_addr_t pc = PC_REGS(regs), brpc;
267	 unsigned	 inst;
268
269	/*
270	 *	User was stopped at pc, e.g. the instruction
271	 *	at pc was not executed.
272	 */
273	inst = db_get_value(pc, sizeof(int), FALSE);
274	if (inst_branch(inst) || inst_call(inst)) {
275	    brpc = branch_taken(inst, pc, regs);
276	    if (brpc != pc) {	/* self-branches are hopeless */
277		db_taken_bkpt = db_set_temp_breakpoint(brpc);
278	    }
279	    pc = next_instr_address(pc,1);
280	}
281	pc = next_instr_address(pc,0);
282	db_not_taken_bkpt = db_set_temp_breakpoint(pc);
283}
284
285void
286db_clear_single_step(regs)
287	db_regs_t *regs;
288{
289
290	if (db_not_taken_bkpt != 0) {
291	    db_delete_temp_breakpoint(db_not_taken_bkpt);
292	    db_not_taken_bkpt = 0;
293	}
294	if (db_taken_bkpt != 0) {
295	    db_delete_temp_breakpoint(db_taken_bkpt);
296	    db_taken_bkpt = 0;
297	}
298}
299
300#endif	/* SOFTWARE_SSTEP */
301
302extern int	db_cmd_loop_done;
303
304/* single-step */
305/*ARGSUSED*/
306void
307db_single_step_cmd(addr, have_addr, count, modif)
308	db_expr_t	addr;
309	boolean_t	have_addr;
310	db_expr_t	count;
311	char *		modif;
312{
313	boolean_t	print = FALSE;
314
315	if (count == -1)
316	    count = 1;
317
318	if (modif[0] == 'p')
319	    print = TRUE;
320
321	db_run_mode = STEP_ONCE;
322	db_loop_count = count;
323	db_sstep_print = print;
324	db_inst_count = 0;
325	db_load_count = 0;
326	db_store_count = 0;
327
328	db_cmd_loop_done = 1;
329}
330
331/* trace and print until call/return */
332/*ARGSUSED*/
333void
334db_trace_until_call_cmd(addr, have_addr, count, modif)
335	db_expr_t	addr;
336	boolean_t	have_addr;
337	db_expr_t	count;
338	char *		modif;
339{
340	boolean_t	print = FALSE;
341
342	if (modif[0] == 'p')
343	    print = TRUE;
344
345	db_run_mode = STEP_CALLT;
346	db_sstep_print = print;
347	db_inst_count = 0;
348	db_load_count = 0;
349	db_store_count = 0;
350
351	db_cmd_loop_done = 1;
352}
353
354/*ARGSUSED*/
355void
356db_trace_until_matching_cmd(addr, have_addr, count, modif)
357	db_expr_t	addr;
358	boolean_t	have_addr;
359	db_expr_t	count;
360	char *		modif;
361{
362	boolean_t	print = FALSE;
363
364	if (modif[0] == 'p')
365	    print = TRUE;
366
367	db_run_mode = STEP_RETURN;
368	db_call_depth = 1;
369	db_sstep_print = print;
370	db_inst_count = 0;
371	db_load_count = 0;
372	db_store_count = 0;
373
374	db_cmd_loop_done = 1;
375}
376
377/* continue */
378/*ARGSUSED*/
379void
380db_continue_cmd(addr, have_addr, count, modif)
381	db_expr_t	addr;
382	boolean_t	have_addr;
383	db_expr_t	count;
384	char *		modif;
385{
386	if (modif[0] == 'c')
387	    db_run_mode = STEP_COUNT;
388	else
389	    db_run_mode = STEP_CONTINUE;
390	db_inst_count = 0;
391	db_load_count = 0;
392	db_store_count = 0;
393
394	db_cmd_loop_done = 1;
395}
396