xref: /freebsd/sys/i386/i386/db_trace.c (revision 7bd6fde3)
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 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/kdb.h>
33 #include <sys/proc.h>
34 #include <sys/stack.h>
35 #include <sys/sysent.h>
36 
37 #include <machine/cpu.h>
38 #include <machine/md_var.h>
39 #include <machine/pcb.h>
40 #include <machine/reg.h>
41 
42 #include <vm/vm.h>
43 #include <vm/vm_param.h>
44 #include <vm/pmap.h>
45 
46 #include <ddb/ddb.h>
47 #include <ddb/db_access.h>
48 #include <ddb/db_sym.h>
49 #include <ddb/db_variables.h>
50 
51 static db_varfcn_t db_dr0;
52 static db_varfcn_t db_dr1;
53 static db_varfcn_t db_dr2;
54 static db_varfcn_t db_dr3;
55 static db_varfcn_t db_dr4;
56 static db_varfcn_t db_dr5;
57 static db_varfcn_t db_dr6;
58 static db_varfcn_t db_dr7;
59 static db_varfcn_t db_esp;
60 static db_varfcn_t db_frame;
61 static db_varfcn_t db_ss;
62 
63 /*
64  * Machine register set.
65  */
66 #define	DB_OFFSET(x)	(db_expr_t *)offsetof(struct trapframe, x)
67 struct db_variable db_regs[] = {
68 	{ "cs",		DB_OFFSET(tf_cs),	db_frame },
69 	{ "ds",		DB_OFFSET(tf_ds),	db_frame },
70 	{ "es",		DB_OFFSET(tf_es),	db_frame },
71 	{ "fs",		DB_OFFSET(tf_fs),	db_frame },
72 	{ "ss",		NULL,			db_ss },
73 	{ "eax",	DB_OFFSET(tf_eax),	db_frame },
74 	{ "ecx",	DB_OFFSET(tf_ecx),	db_frame },
75 	{ "edx",	DB_OFFSET(tf_edx),	db_frame },
76 	{ "ebx",	DB_OFFSET(tf_ebx),	db_frame },
77 	{ "esp",	NULL,			db_esp },
78 	{ "ebp",	DB_OFFSET(tf_ebp),	db_frame },
79 	{ "esi",	DB_OFFSET(tf_esi),	db_frame },
80 	{ "edi",	DB_OFFSET(tf_edi),	db_frame },
81 	{ "eip",	DB_OFFSET(tf_eip),	db_frame },
82 	{ "efl",	DB_OFFSET(tf_eflags),	db_frame },
83 #define	DB_N_SHOW_REGS	15	/* Don't show registers after here. */
84 	{ "dr0",	NULL,			db_dr0 },
85 	{ "dr1",	NULL,			db_dr1 },
86 	{ "dr2",	NULL,			db_dr2 },
87 	{ "dr3",	NULL,			db_dr3 },
88 	{ "dr4",	NULL,			db_dr4 },
89 	{ "dr5",	NULL,			db_dr5 },
90 	{ "dr6",	NULL,			db_dr6 },
91 	{ "dr7",	NULL,			db_dr7 },
92 };
93 struct db_variable *db_eregs = db_regs + DB_N_SHOW_REGS;
94 
95 #define DB_DRX_FUNC(reg)		\
96 static int				\
97 db_ ## reg (vp, valuep, op)		\
98 	struct db_variable *vp;		\
99 	db_expr_t * valuep;		\
100 	int op;				\
101 {					\
102 	if (op == DB_VAR_GET)		\
103 		*valuep = r ## reg ();	\
104 	else				\
105 		load_ ## reg (*valuep); \
106 	return (1);			\
107 }
108 
109 DB_DRX_FUNC(dr0)
110 DB_DRX_FUNC(dr1)
111 DB_DRX_FUNC(dr2)
112 DB_DRX_FUNC(dr3)
113 DB_DRX_FUNC(dr4)
114 DB_DRX_FUNC(dr5)
115 DB_DRX_FUNC(dr6)
116 DB_DRX_FUNC(dr7)
117 
118 static __inline int
119 get_esp(struct trapframe *tf)
120 {
121 	return ((ISPL(tf->tf_cs)) ? tf->tf_esp :
122 	    (db_expr_t)tf + (uintptr_t)DB_OFFSET(tf_esp));
123 }
124 
125 static int
126 db_frame(struct db_variable *vp, db_expr_t *valuep, int op)
127 {
128 	int *reg;
129 
130 	if (kdb_frame == NULL)
131 		return (0);
132 
133 	reg = (int *)((uintptr_t)kdb_frame + (db_expr_t)vp->valuep);
134 	if (op == DB_VAR_GET)
135 		*valuep = *reg;
136 	else
137 		*reg = *valuep;
138 	return (1);
139 }
140 
141 static int
142 db_esp(struct db_variable *vp, db_expr_t *valuep, int op)
143 {
144 
145 	if (kdb_frame == NULL)
146 		return (0);
147 
148 	if (op == DB_VAR_GET)
149 		*valuep = get_esp(kdb_frame);
150 	else if (ISPL(kdb_frame->tf_cs))
151 		kdb_frame->tf_esp = *valuep;
152 	return (1);
153 }
154 
155 static int
156 db_ss(struct db_variable *vp, db_expr_t *valuep, int op)
157 {
158 
159 	if (kdb_frame == NULL)
160 		return (0);
161 
162 	if (op == DB_VAR_GET)
163 		*valuep = (ISPL(kdb_frame->tf_cs)) ? kdb_frame->tf_ss : rss();
164 	else if (ISPL(kdb_frame->tf_cs))
165 		kdb_frame->tf_ss = *valuep;
166 	return (1);
167 }
168 
169 /*
170  * Stack trace.
171  */
172 #define	INKERNEL(va)	(((vm_offset_t)(va)) >= USRSTACK && \
173 	    ((vm_offset_t)(va)) < VM_MAX_KERNEL_ADDRESS)
174 
175 struct i386_frame {
176 	struct i386_frame	*f_frame;
177 	int			f_retaddr;
178 	int			f_arg0;
179 };
180 
181 #define NORMAL		0
182 #define	TRAP		1
183 #define	INTERRUPT	2
184 #define	SYSCALL		3
185 #define	DOUBLE_FAULT	4
186 #define	TRAP_INTERRUPT	5
187 
188 static void db_nextframe(struct i386_frame **, db_addr_t *, struct thread *);
189 static int db_numargs(struct i386_frame *);
190 static void db_print_stack_entry(const char *, int, char **, int *, db_addr_t);
191 static void decode_syscall(int, struct thread *);
192 
193 static const char * watchtype_str(int type);
194 int  i386_set_watch(int watchnum, unsigned int watchaddr, int size, int access,
195 		    struct dbreg *d);
196 int  i386_clr_watch(int watchnum, struct dbreg *d);
197 
198 /*
199  * Figure out how many arguments were passed into the frame at "fp".
200  */
201 static int
202 db_numargs(fp)
203 	struct i386_frame *fp;
204 {
205 	char   *argp;
206 	int	inst;
207 	int	args;
208 
209 	argp = (char *)db_get_value((int)&fp->f_retaddr, 4, FALSE);
210 	/*
211 	 * XXX etext is wrong for LKMs.  We should attempt to interpret
212 	 * the instruction at the return address in all cases.  This
213 	 * may require better fault handling.
214 	 */
215 	if (argp < btext || argp >= etext) {
216 		args = -1;
217 	} else {
218 retry:
219 		inst = db_get_value((int)argp, 4, FALSE);
220 		if ((inst & 0xff) == 0x59)	/* popl %ecx */
221 			args = 1;
222 		else if ((inst & 0xffff) == 0xc483)	/* addl $Ibs, %esp */
223 			args = ((inst >> 16) & 0xff) / 4;
224 		else if ((inst & 0xf8ff) == 0xc089) {	/* movl %eax, %Reg */
225 			argp += 2;
226 			goto retry;
227 		} else
228 			args = -1;
229 	}
230 	return (args);
231 }
232 
233 static void
234 db_print_stack_entry(name, narg, argnp, argp, callpc)
235 	const char *name;
236 	int narg;
237 	char **argnp;
238 	int *argp;
239 	db_addr_t callpc;
240 {
241 	int n = narg >= 0 ? narg : 5;
242 
243 	db_printf("%s(", name);
244 	while (n) {
245 		if (argnp)
246 			db_printf("%s=", *argnp++);
247 		db_printf("%r", db_get_value((int)argp, 4, FALSE));
248 		argp++;
249 		if (--n != 0)
250 			db_printf(",");
251 	}
252 	if (narg < 0)
253 		db_printf(",...");
254 	db_printf(") at ");
255 	db_printsym(callpc, DB_STGY_PROC);
256 	db_printf("\n");
257 }
258 
259 static void
260 decode_syscall(int number, struct thread *td)
261 {
262 	struct proc *p;
263 	c_db_sym_t sym;
264 	db_expr_t diff;
265 	sy_call_t *f;
266 	const char *symname;
267 
268 	db_printf(" (%d", number);
269 	p = (td != NULL) ? td->td_proc : NULL;
270 	if (p != NULL && 0 <= number && number < p->p_sysent->sv_size) {
271 		f = p->p_sysent->sv_table[number].sy_call;
272 		sym = db_search_symbol((db_addr_t)f, DB_STGY_ANY, &diff);
273 		if (sym != DB_SYM_NULL && diff == 0) {
274 			db_symbol_values(sym, &symname, NULL);
275 			db_printf(", %s, %s", p->p_sysent->sv_name, symname);
276 		}
277 	}
278 	db_printf(")");
279 }
280 
281 /*
282  * Figure out the next frame up in the call stack.
283  */
284 static void
285 db_nextframe(struct i386_frame **fp, db_addr_t *ip, struct thread *td)
286 {
287 	struct trapframe *tf;
288 	int frame_type;
289 	int eip, esp, ebp;
290 	db_expr_t offset;
291 	c_db_sym_t sym;
292 	const char *name;
293 
294 	eip = db_get_value((int) &(*fp)->f_retaddr, 4, FALSE);
295 	ebp = db_get_value((int) &(*fp)->f_frame, 4, FALSE);
296 
297 	/*
298 	 * Figure out frame type.  We look at the address just before
299 	 * the saved instruction pointer as the saved EIP is after the
300 	 * call function, and if the function being called is marked as
301 	 * dead (such as panic() at the end of dblfault_handler()), then
302 	 * the instruction at the saved EIP will be part of a different
303 	 * function (syscall() in this example) rather than the one that
304 	 * actually made the call.
305 	 */
306 	frame_type = NORMAL;
307 	sym = db_search_symbol(eip - 1, DB_STGY_ANY, &offset);
308 	db_symbol_values(sym, &name, NULL);
309 	if (name != NULL) {
310 		if (strcmp(name, "calltrap") == 0 ||
311 		    strcmp(name, "fork_trampoline") == 0)
312 			frame_type = TRAP;
313 		else if (strncmp(name, "Xatpic_intr", 11) == 0 ||
314 		    strncmp(name, "Xapic_isr", 9) == 0)
315 			frame_type = INTERRUPT;
316 		else if (strcmp(name, "Xlcall_syscall") == 0 ||
317 		    strcmp(name, "Xint0x80_syscall") == 0)
318 			frame_type = SYSCALL;
319 		else if (strcmp(name, "dblfault_handler") == 0)
320 			frame_type = DOUBLE_FAULT;
321 		/* XXX: These are interrupts with trap frames. */
322 		else if (strcmp(name, "Xtimerint") == 0 ||
323 		    strcmp(name, "Xcpustop") == 0 ||
324 		    strcmp(name, "Xrendezvous") == 0 ||
325 		    strcmp(name, "Xipi_intr_bitmap_handler") == 0 ||
326 		    strcmp(name, "Xlazypmap") == 0)
327 			frame_type = TRAP_INTERRUPT;
328 	}
329 
330 	/*
331 	 * Normal frames need no special processing.
332 	 */
333 	if (frame_type == NORMAL) {
334 		*ip = (db_addr_t) eip;
335 		*fp = (struct i386_frame *) ebp;
336 		return;
337 	}
338 
339 	db_print_stack_entry(name, 0, 0, 0, eip);
340 
341 	/*
342 	 * For a double fault, we have to snag the values from the
343 	 * previous TSS since a double fault uses a task gate to
344 	 * switch to a known good state.
345 	 */
346 	if (frame_type == DOUBLE_FAULT) {
347 		esp = PCPU_GET(common_tss.tss_esp);
348 		eip = PCPU_GET(common_tss.tss_eip);
349 		ebp = PCPU_GET(common_tss.tss_ebp);
350 		db_printf(
351 		    "--- trap 0x17, eip = %#r, esp = %#r, ebp = %#r ---\n",
352 		    eip, esp, ebp);
353 		*ip = (db_addr_t) eip;
354 		*fp = (struct i386_frame *) ebp;
355 		return;
356 	}
357 
358 	/*
359 	 * Point to base of trapframe which is just above the
360 	 * current frame.
361 	 */
362 	if (frame_type == INTERRUPT)
363 		tf = (struct trapframe *)((int)*fp + 16);
364 	else
365 		tf = (struct trapframe *)((int)*fp + 12);
366 
367 	if (INKERNEL((int) tf)) {
368 		esp = get_esp(tf);
369 		eip = tf->tf_eip;
370 		ebp = tf->tf_ebp;
371 		switch (frame_type) {
372 		case TRAP:
373 			db_printf("--- trap %#r", tf->tf_trapno);
374 			break;
375 		case SYSCALL:
376 			db_printf("--- syscall");
377 			decode_syscall(tf->tf_eax, td);
378 			break;
379 		case TRAP_INTERRUPT:
380 		case INTERRUPT:
381 			db_printf("--- interrupt");
382 			break;
383 		default:
384 			panic("The moon has moved again.");
385 		}
386 		db_printf(", eip = %#r, esp = %#r, ebp = %#r ---\n", eip,
387 		    esp, ebp);
388 	}
389 
390 	*ip = (db_addr_t) eip;
391 	*fp = (struct i386_frame *) ebp;
392 }
393 
394 static int
395 db_backtrace(struct thread *td, struct trapframe *tf, struct i386_frame *frame,
396     db_addr_t pc, int count)
397 {
398 	struct i386_frame *actframe;
399 #define MAXNARG	16
400 	char *argnames[MAXNARG], **argnp = NULL;
401 	const char *name;
402 	int *argp;
403 	db_expr_t offset;
404 	c_db_sym_t sym;
405 	int instr, narg;
406 	boolean_t first;
407 
408 	/*
409 	 * If an indirect call via an invalid pointer caused a trap,
410 	 * %pc contains the invalid address while the return address
411 	 * of the unlucky caller has been saved by CPU on the stack
412 	 * just before the trap frame.  In this case, try to recover
413 	 * the caller's address so that the first frame is assigned
414 	 * to the right spot in the right function, for that is where
415 	 * the failure actually happened.
416 	 *
417 	 * This trick depends on the fault address stashed in tf_err
418 	 * by trap_fatal() before entering KDB.
419 	 */
420 	if (kdb_frame && pc == kdb_frame->tf_err) {
421 		/*
422 		 * Find where the trap frame actually ends.
423 		 * It won't contain tf_esp or tf_ss unless crossing rings.
424 		 */
425 		if (ISPL(kdb_frame->tf_cs))
426 			instr = (int)(kdb_frame + 1);
427 		else
428 			instr = (int)&kdb_frame->tf_esp;
429 		pc = db_get_value(instr, 4, FALSE);
430 	}
431 
432 	if (count == -1)
433 		count = 1024;
434 
435 	first = TRUE;
436 	while (count-- && !db_pager_quit) {
437 		sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
438 		db_symbol_values(sym, &name, NULL);
439 
440 		/*
441 		 * Attempt to determine a (possibly fake) frame that gives
442 		 * the caller's pc.  It may differ from `frame' if the
443 		 * current function never sets up a standard frame or hasn't
444 		 * set one up yet or has just discarded one.  The last two
445 		 * cases can be guessed fairly reliably for code generated
446 		 * by gcc.  The first case is too much trouble to handle in
447 		 * general because the amount of junk on the stack depends
448 		 * on the pc (the special handling of "calltrap", etc. in
449 		 * db_nextframe() works because the `next' pc is special).
450 		 */
451 		actframe = frame;
452 		if (first) {
453 			if (tf != NULL) {
454 				instr = db_get_value(pc, 4, FALSE);
455 				if ((instr & 0xffffff) == 0x00e58955) {
456 					/* pushl %ebp; movl %esp, %ebp */
457 					actframe = (void *)(get_esp(tf) - 4);
458 				} else if ((instr & 0xffff) == 0x0000e589) {
459 					/* movl %esp, %ebp */
460 					actframe = (void *)get_esp(tf);
461 					if (tf->tf_ebp == 0) {
462 						/* Fake frame better. */
463 						frame = actframe;
464 					}
465 				} else if ((instr & 0xff) == 0x000000c3) {
466 					/* ret */
467 					actframe = (void *)(get_esp(tf) - 4);
468 				} else if (offset == 0) {
469 					/* Probably an assembler symbol. */
470 					actframe = (void *)(get_esp(tf) - 4);
471 				}
472 			} else if (strcmp(name, "fork_trampoline") == 0) {
473 				/*
474 				 * Don't try to walk back on a stack for a
475 				 * process that hasn't actually been run yet.
476 				 */
477 				db_print_stack_entry(name, 0, 0, 0, pc);
478 				break;
479 			}
480 			first = FALSE;
481 		}
482 
483 		argp = &actframe->f_arg0;
484 		narg = MAXNARG;
485 		if (sym != NULL && db_sym_numargs(sym, &narg, argnames)) {
486 			argnp = argnames;
487 		} else {
488 			narg = db_numargs(frame);
489 		}
490 
491 		db_print_stack_entry(name, narg, argnp, argp, pc);
492 
493 		if (actframe != frame) {
494 			/* `frame' belongs to caller. */
495 			pc = (db_addr_t)
496 			    db_get_value((int)&actframe->f_retaddr, 4, FALSE);
497 			continue;
498 		}
499 
500 		db_nextframe(&frame, &pc, td);
501 
502 		if (INKERNEL((int)pc) && !INKERNEL((int) frame)) {
503 			sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
504 			db_symbol_values(sym, &name, NULL);
505 			db_print_stack_entry(name, 0, 0, 0, pc);
506 			break;
507 		}
508 		if (!INKERNEL((int) frame)) {
509 			break;
510 		}
511 	}
512 
513 	return (0);
514 }
515 
516 void
517 db_trace_self(void)
518 {
519 	struct i386_frame *frame;
520 	db_addr_t callpc;
521 	register_t ebp;
522 
523 	__asm __volatile("movl %%ebp,%0" : "=r" (ebp));
524 	frame = (struct i386_frame *)ebp;
525 	callpc = (db_addr_t)db_get_value((int)&frame->f_retaddr, 4, FALSE);
526 	frame = frame->f_frame;
527 	db_backtrace(curthread, NULL, frame, callpc, -1);
528 }
529 
530 int
531 db_trace_thread(struct thread *thr, int count)
532 {
533 	struct pcb *ctx;
534 
535 	ctx = kdb_thr_ctx(thr);
536 	return (db_backtrace(thr, NULL, (struct i386_frame *)ctx->pcb_ebp,
537 		    ctx->pcb_eip, count));
538 }
539 
540 void
541 stack_save(struct stack *st)
542 {
543 	struct i386_frame *frame;
544 	vm_offset_t callpc;
545 	register_t ebp;
546 
547 	stack_zero(st);
548 	__asm __volatile("movl %%ebp,%0" : "=r" (ebp));
549 	frame = (struct i386_frame *)ebp;
550 	while (1) {
551 		if (!INKERNEL(frame))
552 			break;
553 		callpc = frame->f_retaddr;
554 		if (!INKERNEL(callpc))
555 			break;
556 		if (stack_put(st, callpc) == -1)
557 			break;
558 		if (frame->f_frame <= frame ||
559 		    (vm_offset_t)frame->f_frame >=
560 		    (vm_offset_t)ebp + KSTACK_PAGES * PAGE_SIZE)
561 			break;
562 		frame = frame->f_frame;
563 	}
564 }
565 
566 int
567 i386_set_watch(watchnum, watchaddr, size, access, d)
568 	int watchnum;
569 	unsigned int watchaddr;
570 	int size;
571 	int access;
572 	struct dbreg *d;
573 {
574 	int i, len;
575 
576 	if (watchnum == -1) {
577 		for (i = 0; i < 4; i++)
578 			if (!DBREG_DR7_ENABLED(d->dr[7], i))
579 				break;
580 		if (i < 4)
581 			watchnum = i;
582 		else
583 			return (-1);
584 	}
585 
586 	switch (access) {
587 	case DBREG_DR7_EXEC:
588 		size = 1; /* size must be 1 for an execution breakpoint */
589 		/* fall through */
590 	case DBREG_DR7_WRONLY:
591 	case DBREG_DR7_RDWR:
592 		break;
593 	default:
594 		return (-1);
595 	}
596 
597 	/*
598 	 * we can watch a 1, 2, or 4 byte sized location
599 	 */
600 	switch (size) {
601 	case 1:
602 		len = DBREG_DR7_LEN_1;
603 		break;
604 	case 2:
605 		len = DBREG_DR7_LEN_2;
606 		break;
607 	case 4:
608 		len = DBREG_DR7_LEN_4;
609 		break;
610 	default:
611 		return (-1);
612 	}
613 
614 	/* clear the bits we are about to affect */
615 	d->dr[7] &= ~DBREG_DR7_MASK(watchnum);
616 
617 	/* set drN register to the address, N=watchnum */
618 	DBREG_DRX(d, watchnum) = watchaddr;
619 
620 	/* enable the watchpoint */
621 	d->dr[7] |= DBREG_DR7_SET(watchnum, len, access,
622 	    DBREG_DR7_GLOBAL_ENABLE);
623 
624 	return (watchnum);
625 }
626 
627 
628 int
629 i386_clr_watch(watchnum, d)
630 	int watchnum;
631 	struct dbreg *d;
632 {
633 
634 	if (watchnum < 0 || watchnum >= 4)
635 		return (-1);
636 
637 	d->dr[7] &= ~DBREG_DR7_MASK(watchnum);
638 	DBREG_DRX(d, watchnum) = 0;
639 
640 	return (0);
641 }
642 
643 
644 int
645 db_md_set_watchpoint(addr, size)
646 	db_expr_t addr;
647 	db_expr_t size;
648 {
649 	struct dbreg d;
650 	int avail, i, wsize;
651 
652 	fill_dbregs(NULL, &d);
653 
654 	avail = 0;
655 	for(i = 0; i < 4; i++) {
656 		if (!DBREG_DR7_ENABLED(d.dr[7], i))
657 			avail++;
658 	}
659 
660 	if (avail * 4 < size)
661 		return (-1);
662 
663 	for (i = 0; i < 4 && (size > 0); i++) {
664 		if (!DBREG_DR7_ENABLED(d.dr[7], i)) {
665 			if (size > 2)
666 				wsize = 4;
667 			else
668 				wsize = size;
669 			i386_set_watch(i, addr, wsize,
670 				       DBREG_DR7_WRONLY, &d);
671 			addr += wsize;
672 			size -= wsize;
673 		}
674 	}
675 
676 	set_dbregs(NULL, &d);
677 
678 	return(0);
679 }
680 
681 
682 int
683 db_md_clr_watchpoint(addr, size)
684 	db_expr_t addr;
685 	db_expr_t size;
686 {
687 	struct dbreg d;
688 	int i;
689 
690 	fill_dbregs(NULL, &d);
691 
692 	for(i = 0; i < 4; i++) {
693 		if (DBREG_DR7_ENABLED(d.dr[7], i)) {
694 			if ((DBREG_DRX((&d), i) >= addr) &&
695 			    (DBREG_DRX((&d), i) < addr+size))
696 				i386_clr_watch(i, &d);
697 
698 		}
699 	}
700 
701 	set_dbregs(NULL, &d);
702 
703 	return(0);
704 }
705 
706 
707 static const char *
708 watchtype_str(type)
709 	int type;
710 {
711 	switch (type) {
712 		case DBREG_DR7_EXEC   : return "execute";    break;
713 		case DBREG_DR7_RDWR   : return "read/write"; break;
714 		case DBREG_DR7_WRONLY : return "write";	     break;
715 		default		      : return "invalid";    break;
716 	}
717 }
718 
719 
720 void
721 db_md_list_watchpoints()
722 {
723 	struct dbreg d;
724 	int i, len, type;
725 
726 	fill_dbregs(NULL, &d);
727 
728 	db_printf("\nhardware watchpoints:\n");
729 	db_printf("  watch    status        type  len     address\n");
730 	db_printf("  -----  --------  ----------  ---  ----------\n");
731 	for (i = 0; i < 4; i++) {
732 		if (DBREG_DR7_ENABLED(d.dr[7], i)) {
733 			type = DBREG_DR7_ACCESS(d.dr[7], i);
734 			len = DBREG_DR7_LEN(d.dr[7], i);
735 			db_printf("  %-5d  %-8s  %10s  %3d  ",
736 			    i, "enabled", watchtype_str(type), len + 1);
737 			db_printsym((db_addr_t)DBREG_DRX((&d), i), DB_STGY_ANY);
738 			db_printf("\n");
739 		} else {
740 			db_printf("  %-5d  disabled\n", i);
741 		}
742 	}
743 
744 	db_printf("\ndebug register values:\n");
745 	for (i = 0; i < 8; i++) {
746 		db_printf("  dr%d 0x%08x\n", i, DBREG_DRX((&d), i));
747 	}
748 	db_printf("\n");
749 }
750 
751 
752