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 "opt_compat.h"
31
32#include <sys/param.h>
33#include <sys/systm.h>
34#include <sys/kdb.h>
35#include <sys/proc.h>
36#include <sys/smp.h>
37#include <sys/stack.h>
38#include <sys/sysent.h>
39
40#include <machine/cpu.h>
41#include <machine/md_var.h>
42#include <machine/pcb.h>
43#include <machine/reg.h>
44#include <machine/stack.h>
45
46#include <vm/vm.h>
47#include <vm/vm_param.h>
48#include <vm/pmap.h>
49
50#include <ddb/ddb.h>
51#include <ddb/db_access.h>
52#include <ddb/db_sym.h>
53#include <ddb/db_variables.h>
54
55static db_varfcn_t db_dr0;
56static db_varfcn_t db_dr1;
57static db_varfcn_t db_dr2;
58static db_varfcn_t db_dr3;
59static db_varfcn_t db_dr4;
60static db_varfcn_t db_dr5;
61static db_varfcn_t db_dr6;
62static db_varfcn_t db_dr7;
63static db_varfcn_t db_frame;
64static db_varfcn_t db_rsp;
65static db_varfcn_t db_ss;
66
67CTASSERT(sizeof(struct dbreg) == sizeof(((struct pcpu *)NULL)->pc_dbreg));
68
69/*
70 * Machine register set.
71 */
72#define	DB_OFFSET(x)	(db_expr_t *)offsetof(struct trapframe, x)
73struct db_variable db_regs[] = {
74	{ "cs",		DB_OFFSET(tf_cs),	db_frame },
75	{ "ds",		DB_OFFSET(tf_ds),	db_frame },
76	{ "es",		DB_OFFSET(tf_es),	db_frame },
77	{ "fs",		DB_OFFSET(tf_fs),	db_frame },
78	{ "gs",		DB_OFFSET(tf_gs),	db_frame },
79	{ "ss",		NULL,			db_ss },
80	{ "rax",	DB_OFFSET(tf_rax),	db_frame },
81	{ "rcx",        DB_OFFSET(tf_rcx),	db_frame },
82	{ "rdx",	DB_OFFSET(tf_rdx),	db_frame },
83	{ "rbx",	DB_OFFSET(tf_rbx),	db_frame },
84	{ "rsp",	NULL,			db_rsp },
85	{ "rbp",	DB_OFFSET(tf_rbp),	db_frame },
86	{ "rsi",	DB_OFFSET(tf_rsi),	db_frame },
87	{ "rdi",	DB_OFFSET(tf_rdi),	db_frame },
88	{ "r8",		DB_OFFSET(tf_r8),	db_frame },
89	{ "r9",		DB_OFFSET(tf_r9),	db_frame },
90	{ "r10",	DB_OFFSET(tf_r10),	db_frame },
91	{ "r11",	DB_OFFSET(tf_r11),	db_frame },
92	{ "r12",	DB_OFFSET(tf_r12),	db_frame },
93	{ "r13",	DB_OFFSET(tf_r13),	db_frame },
94	{ "r14",	DB_OFFSET(tf_r14),	db_frame },
95	{ "r15",	DB_OFFSET(tf_r15),	db_frame },
96	{ "rip",	DB_OFFSET(tf_rip),	db_frame },
97	{ "rflags",	DB_OFFSET(tf_rflags),	db_frame },
98#define	DB_N_SHOW_REGS	24	/* Don't show registers after here. */
99	{ "dr0",	NULL,			db_dr0 },
100	{ "dr1",	NULL,			db_dr1 },
101	{ "dr2",	NULL,			db_dr2 },
102	{ "dr3",	NULL,			db_dr3 },
103	{ "dr4",	NULL,			db_dr4 },
104	{ "dr5",	NULL,			db_dr5 },
105	{ "dr6",	NULL,			db_dr6 },
106	{ "dr7",	NULL,			db_dr7 },
107};
108struct db_variable *db_eregs = db_regs + DB_N_SHOW_REGS;
109
110#define DB_DRX_FUNC(reg)		\
111static int				\
112db_ ## reg (vp, valuep, op)		\
113	struct db_variable *vp;		\
114	db_expr_t * valuep;		\
115	int op;				\
116{					\
117	if (op == DB_VAR_GET)		\
118		*valuep = r ## reg ();	\
119	else				\
120		load_ ## reg (*valuep); \
121	return (1);			\
122}
123
124DB_DRX_FUNC(dr0)
125DB_DRX_FUNC(dr1)
126DB_DRX_FUNC(dr2)
127DB_DRX_FUNC(dr3)
128DB_DRX_FUNC(dr4)
129DB_DRX_FUNC(dr5)
130DB_DRX_FUNC(dr6)
131DB_DRX_FUNC(dr7)
132
133static __inline long
134get_rsp(struct trapframe *tf)
135{
136	return ((ISPL(tf->tf_cs)) ? tf->tf_rsp :
137	    (db_expr_t)tf + offsetof(struct trapframe, tf_rsp));
138}
139
140static int
141db_frame(struct db_variable *vp, db_expr_t *valuep, int op)
142{
143	long *reg;
144
145	if (kdb_frame == NULL)
146		return (0);
147
148	reg = (long *)((uintptr_t)kdb_frame + (db_expr_t)vp->valuep);
149	if (op == DB_VAR_GET)
150		*valuep = *reg;
151	else
152		*reg = *valuep;
153	return (1);
154}
155
156static int
157db_rsp(struct db_variable *vp, db_expr_t *valuep, int op)
158{
159
160	if (kdb_frame == NULL)
161		return (0);
162
163	if (op == DB_VAR_GET)
164		*valuep = get_rsp(kdb_frame);
165	else if (ISPL(kdb_frame->tf_cs))
166		kdb_frame->tf_rsp = *valuep;
167	return (1);
168}
169
170static int
171db_ss(struct db_variable *vp, db_expr_t *valuep, int op)
172{
173
174	if (kdb_frame == NULL)
175		return (0);
176
177	if (op == DB_VAR_GET)
178		*valuep = (ISPL(kdb_frame->tf_cs)) ? kdb_frame->tf_ss : rss();
179	else if (ISPL(kdb_frame->tf_cs))
180		kdb_frame->tf_ss = *valuep;
181	return (1);
182}
183
184#define NORMAL		0
185#define	TRAP		1
186#define	INTERRUPT	2
187#define	SYSCALL		3
188#define	TRAP_INTERRUPT	5
189
190static void db_nextframe(struct amd64_frame **, db_addr_t *, struct thread *);
191static int db_numargs(struct amd64_frame *);
192static void db_print_stack_entry(const char *, int, char **, long *, db_addr_t,
193    void *);
194static void decode_syscall(int, struct thread *);
195
196static const char * watchtype_str(int type);
197int  amd64_set_watch(int watchnum, unsigned long watchaddr, int size,
198		    int access, struct dbreg *d);
199int  amd64_clr_watch(int watchnum, struct dbreg *d);
200
201/*
202 * Figure out how many arguments were passed into the frame at "fp".
203 */
204static int
205db_numargs(fp)
206	struct amd64_frame *fp;
207{
208#if 1
209	return (0);	/* regparm, needs dwarf2 info */
210#else
211	long	*argp;
212	int	inst;
213	int	args;
214
215	argp = (long *)db_get_value((long)&fp->f_retaddr, 8, FALSE);
216	/*
217	 * XXX etext is wrong for LKMs.  We should attempt to interpret
218	 * the instruction at the return address in all cases.  This
219	 * may require better fault handling.
220	 */
221	if (argp < (long *)btext || argp >= (long *)etext) {
222		args = 5;
223	} else {
224		inst = db_get_value((long)argp, 4, FALSE);
225		if ((inst & 0xff) == 0x59)	/* popl %ecx */
226			args = 1;
227		else if ((inst & 0xffff) == 0xc483)	/* addl $Ibs, %esp */
228			args = ((inst >> 16) & 0xff) / 4;
229		else
230			args = 5;
231	}
232	return (args);
233#endif
234}
235
236static void
237db_print_stack_entry(name, narg, argnp, argp, callpc, frame)
238	const char *name;
239	int narg;
240	char **argnp;
241	long *argp;
242	db_addr_t callpc;
243	void *frame;
244{
245	db_printf("%s(", name);
246#if 0
247	while (narg) {
248		if (argnp)
249			db_printf("%s=", *argnp++);
250		db_printf("%lr", (long)db_get_value((long)argp, 8, FALSE));
251		argp++;
252		if (--narg != 0)
253			db_printf(",");
254	}
255#endif
256	db_printf(") at ");
257	db_printsym(callpc, DB_STGY_PROC);
258	if (frame != NULL)
259		db_printf("/frame 0x%lx", (register_t)frame);
260	db_printf("\n");
261}
262
263static void
264decode_syscall(int number, struct thread *td)
265{
266	struct proc *p;
267	c_db_sym_t sym;
268	db_expr_t diff;
269	sy_call_t *f;
270	const char *symname;
271
272	db_printf(" (%d", number);
273	p = (td != NULL) ? td->td_proc : NULL;
274	if (p != NULL && 0 <= number && number < p->p_sysent->sv_size) {
275		f = p->p_sysent->sv_table[number].sy_call;
276		sym = db_search_symbol((db_addr_t)f, DB_STGY_ANY, &diff);
277		if (sym != DB_SYM_NULL && diff == 0) {
278			db_symbol_values(sym, &symname, NULL);
279			db_printf(", %s, %s", p->p_sysent->sv_name, symname);
280		}
281	}
282	db_printf(")");
283}
284
285/*
286 * Figure out the next frame up in the call stack.
287 */
288static void
289db_nextframe(struct amd64_frame **fp, db_addr_t *ip, struct thread *td)
290{
291	struct trapframe *tf;
292	int frame_type;
293	long rip, rsp, rbp;
294	db_expr_t offset;
295	c_db_sym_t sym;
296	const char *name;
297
298	rip = db_get_value((long) &(*fp)->f_retaddr, 8, FALSE);
299	rbp = db_get_value((long) &(*fp)->f_frame, 8, FALSE);
300
301	/*
302	 * Figure out frame type.  We look at the address just before
303	 * the saved instruction pointer as the saved EIP is after the
304	 * call function, and if the function being called is marked as
305	 * dead (such as panic() at the end of dblfault_handler()), then
306	 * the instruction at the saved EIP will be part of a different
307	 * function (syscall() in this example) rather than the one that
308	 * actually made the call.
309	 */
310	frame_type = NORMAL;
311	sym = db_search_symbol(rip - 1, DB_STGY_ANY, &offset);
312	db_symbol_values(sym, &name, NULL);
313	if (name != NULL) {
314		if (strcmp(name, "calltrap") == 0 ||
315		    strcmp(name, "fork_trampoline") == 0 ||
316		    strcmp(name, "nmi_calltrap") == 0 ||
317		    strcmp(name, "Xdblfault") == 0)
318			frame_type = TRAP;
319		else if (strncmp(name, "Xatpic_intr", 11) == 0 ||
320		    strncmp(name, "Xapic_isr", 9) == 0 ||
321		    strcmp(name, "Xtimerint") == 0 ||
322		    strcmp(name, "Xipi_intr_bitmap_handler") == 0 ||
323		    strcmp(name, "Xcpustop") == 0 ||
324		    strcmp(name, "Xcpususpend") == 0 ||
325		    strcmp(name, "Xrendezvous") == 0)
326			frame_type = INTERRUPT;
327		else if (strcmp(name, "Xfast_syscall") == 0)
328			frame_type = SYSCALL;
329#ifdef COMPAT_FREEBSD32
330		else if (strcmp(name, "Xint0x80_syscall") == 0)
331			frame_type = SYSCALL;
332#endif
333		/* XXX: These are interrupts with trap frames. */
334		else if (strcmp(name, "Xtimerint") == 0 ||
335		    strcmp(name, "Xcpustop") == 0 ||
336		    strcmp(name, "Xcpususpend") == 0 ||
337		    strcmp(name, "Xrendezvous") == 0 ||
338		    strcmp(name, "Xipi_intr_bitmap_handler") == 0)
339			frame_type = TRAP_INTERRUPT;
340	}
341
342	/*
343	 * Normal frames need no special processing.
344	 */
345	if (frame_type == NORMAL) {
346		*ip = (db_addr_t) rip;
347		*fp = (struct amd64_frame *) rbp;
348		return;
349	}
350
351	db_print_stack_entry(name, 0, 0, 0, rip, &(*fp)->f_frame);
352
353	/*
354	 * Point to base of trapframe which is just above the
355	 * current frame.
356	 */
357	tf = (struct trapframe *)((long)*fp + 16);
358
359	if (INKERNEL((long) tf)) {
360		rsp = get_rsp(tf);
361		rip = tf->tf_rip;
362		rbp = tf->tf_rbp;
363		switch (frame_type) {
364		case TRAP:
365			db_printf("--- trap %#r", tf->tf_trapno);
366			break;
367		case SYSCALL:
368			db_printf("--- syscall");
369			decode_syscall(tf->tf_rax, td);
370			break;
371		case TRAP_INTERRUPT:
372		case INTERRUPT:
373			db_printf("--- interrupt");
374			break;
375		default:
376			panic("The moon has moved again.");
377		}
378		db_printf(", rip = %#lr, rsp = %#lr, rbp = %#lr ---\n", rip,
379		    rsp, rbp);
380	}
381
382	*ip = (db_addr_t) rip;
383	*fp = (struct amd64_frame *) rbp;
384}
385
386static int
387db_backtrace(struct thread *td, struct trapframe *tf,
388    struct amd64_frame *frame, db_addr_t pc, int count)
389{
390	struct amd64_frame *actframe;
391#define MAXNARG	16
392	char *argnames[MAXNARG], **argnp = NULL;
393	const char *name;
394	long *argp;
395	db_expr_t offset;
396	c_db_sym_t sym;
397	int narg;
398	boolean_t first;
399
400	if (count == -1)
401		count = 1024;
402
403	first = TRUE;
404	while (count-- && !db_pager_quit) {
405		sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
406		db_symbol_values(sym, &name, NULL);
407
408		/*
409		 * Attempt to determine a (possibly fake) frame that gives
410		 * the caller's pc.  It may differ from `frame' if the
411		 * current function never sets up a standard frame or hasn't
412		 * set one up yet or has just discarded one.  The last two
413		 * cases can be guessed fairly reliably for code generated
414		 * by gcc.  The first case is too much trouble to handle in
415		 * general because the amount of junk on the stack depends
416		 * on the pc (the special handling of "calltrap", etc. in
417		 * db_nextframe() works because the `next' pc is special).
418		 */
419		actframe = frame;
420		if (first) {
421			if (tf != NULL) {
422				int instr;
423
424				instr = db_get_value(pc, 4, FALSE);
425				if ((instr & 0xffffffff) == 0xe5894855) {
426					/* pushq %rbp; movq %rsp, %rbp */
427					actframe = (void *)(get_rsp(tf) - 8);
428				} else if ((instr & 0xffffff) == 0xe58948) {
429					/* movq %rsp, %rbp */
430					actframe = (void *)get_rsp(tf);
431					if (tf->tf_rbp == 0) {
432						/* Fake frame better. */
433						frame = actframe;
434					}
435				} else if ((instr & 0xff) == 0xc3) {
436					/* ret */
437					actframe = (void *)(get_rsp(tf) - 8);
438				} else if (offset == 0) {
439					/* Probably an assembler symbol. */
440					actframe = (void *)(get_rsp(tf) - 8);
441				}
442			} else if (strcmp(name, "fork_trampoline") == 0) {
443				/*
444				 * Don't try to walk back on a stack for a
445				 * process that hasn't actually been run yet.
446				 */
447				db_print_stack_entry(name, 0, 0, 0, pc,
448				    actframe);
449				break;
450			}
451			first = FALSE;
452		}
453
454		argp = &actframe->f_arg0;
455		narg = MAXNARG;
456		if (sym != NULL && db_sym_numargs(sym, &narg, argnames)) {
457			argnp = argnames;
458		} else {
459			narg = db_numargs(frame);
460		}
461
462		db_print_stack_entry(name, narg, argnp, argp, pc, actframe);
463
464		if (actframe != frame) {
465			/* `frame' belongs to caller. */
466			pc = (db_addr_t)
467			    db_get_value((long)&actframe->f_retaddr, 8, FALSE);
468			continue;
469		}
470
471		db_nextframe(&frame, &pc, td);
472
473		if (INKERNEL((long)pc) && !INKERNEL((long)frame)) {
474			sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
475			db_symbol_values(sym, &name, NULL);
476			db_print_stack_entry(name, 0, 0, 0, pc, frame);
477			break;
478		}
479		if (!INKERNEL((long) frame)) {
480			break;
481		}
482	}
483
484	return (0);
485}
486
487void
488db_trace_self(void)
489{
490	struct amd64_frame *frame;
491	db_addr_t callpc;
492	register_t rbp;
493
494	__asm __volatile("movq %%rbp,%0" : "=r" (rbp));
495	frame = (struct amd64_frame *)rbp;
496	callpc = (db_addr_t)db_get_value((long)&frame->f_retaddr, 8, FALSE);
497	frame = frame->f_frame;
498	db_backtrace(curthread, NULL, frame, callpc, -1);
499}
500
501int
502db_trace_thread(struct thread *thr, int count)
503{
504	struct pcb *ctx;
505
506	ctx = kdb_thr_ctx(thr);
507	return (db_backtrace(thr, NULL, (struct amd64_frame *)ctx->pcb_rbp,
508		    ctx->pcb_rip, count));
509}
510
511int
512amd64_set_watch(watchnum, watchaddr, size, access, d)
513	int watchnum;
514	unsigned long watchaddr;
515	int size;
516	int access;
517	struct dbreg *d;
518{
519	int i, len;
520
521	if (watchnum == -1) {
522		for (i = 0; i < 4; i++)
523			if (!DBREG_DR7_ENABLED(d->dr[7], i))
524				break;
525		if (i < 4)
526			watchnum = i;
527		else
528			return (-1);
529	}
530
531	switch (access) {
532	case DBREG_DR7_EXEC:
533		size = 1; /* size must be 1 for an execution breakpoint */
534		/* fall through */
535	case DBREG_DR7_WRONLY:
536	case DBREG_DR7_RDWR:
537		break;
538	default:
539		return (-1);
540	}
541
542	/*
543	 * we can watch a 1, 2, 4, or 8 byte sized location
544	 */
545	switch (size) {
546	case 1:
547		len = DBREG_DR7_LEN_1;
548		break;
549	case 2:
550		len = DBREG_DR7_LEN_2;
551		break;
552	case 4:
553		len = DBREG_DR7_LEN_4;
554		break;
555	case 8:
556		len = DBREG_DR7_LEN_8;
557		break;
558	default:
559		return (-1);
560	}
561
562	/* clear the bits we are about to affect */
563	d->dr[7] &= ~DBREG_DR7_MASK(watchnum);
564
565	/* set drN register to the address, N=watchnum */
566	DBREG_DRX(d, watchnum) = watchaddr;
567
568	/* enable the watchpoint */
569	d->dr[7] |= DBREG_DR7_SET(watchnum, len, access,
570	    DBREG_DR7_GLOBAL_ENABLE);
571
572	return (watchnum);
573}
574
575
576int
577amd64_clr_watch(watchnum, d)
578	int watchnum;
579	struct dbreg *d;
580{
581
582	if (watchnum < 0 || watchnum >= 4)
583		return (-1);
584
585	d->dr[7] &= ~DBREG_DR7_MASK(watchnum);
586	DBREG_DRX(d, watchnum) = 0;
587
588	return (0);
589}
590
591
592int
593db_md_set_watchpoint(addr, size)
594	db_expr_t addr;
595	db_expr_t size;
596{
597	struct dbreg *d;
598	struct pcpu *pc;
599	int avail, c, cpu, i, wsize;
600
601	d = (struct dbreg *)PCPU_PTR(dbreg);
602	cpu = PCPU_GET(cpuid);
603	fill_dbregs(NULL, d);
604
605	avail = 0;
606	for (i = 0; i < 4; i++) {
607		if (!DBREG_DR7_ENABLED(d->dr[7], i))
608			avail++;
609	}
610
611	if (avail * 8 < size)
612		return (-1);
613
614	for (i = 0; i < 4 && size > 0; i++) {
615		if (!DBREG_DR7_ENABLED(d->dr[7], i)) {
616			if (size >= 8 || (avail == 1 && size > 4))
617				wsize = 8;
618			else if (size > 2)
619				wsize = 4;
620			else
621				wsize = size;
622			amd64_set_watch(i, addr, wsize, DBREG_DR7_WRONLY, d);
623			addr += wsize;
624			size -= wsize;
625			avail--;
626		}
627	}
628
629	set_dbregs(NULL, d);
630	CPU_FOREACH(c) {
631		if (c == cpu)
632			continue;
633		pc = pcpu_find(c);
634		memcpy(pc->pc_dbreg, d, sizeof(*d));
635		pc->pc_dbreg_cmd = PC_DBREG_CMD_LOAD;
636	}
637
638	return (0);
639}
640
641int
642db_md_clr_watchpoint(addr, size)
643	db_expr_t addr;
644	db_expr_t size;
645{
646	struct dbreg *d;
647	struct pcpu *pc;
648	int i, c, cpu;
649
650	d = (struct dbreg *)PCPU_PTR(dbreg);
651	cpu = PCPU_GET(cpuid);
652	fill_dbregs(NULL, d);
653
654	for (i = 0; i < 4; i++) {
655		if (DBREG_DR7_ENABLED(d->dr[7], i)) {
656			if (DBREG_DRX((d), i) >= addr &&
657			    DBREG_DRX((d), i) < addr + size)
658				amd64_clr_watch(i, d);
659
660		}
661	}
662
663	set_dbregs(NULL, d);
664	CPU_FOREACH(c) {
665		if (c == cpu)
666			continue;
667		pc = pcpu_find(c);
668		memcpy(pc->pc_dbreg, d, sizeof(*d));
669		pc->pc_dbreg_cmd = PC_DBREG_CMD_LOAD;
670	}
671
672	return (0);
673}
674
675
676static const char *
677watchtype_str(type)
678	int type;
679{
680	switch (type) {
681		case DBREG_DR7_EXEC   : return "execute";    break;
682		case DBREG_DR7_RDWR   : return "read/write"; break;
683		case DBREG_DR7_WRONLY : return "write";	     break;
684		default		      : return "invalid";    break;
685	}
686}
687
688
689void
690db_md_list_watchpoints()
691{
692	struct dbreg d;
693	int i, len, type;
694
695	fill_dbregs(NULL, &d);
696
697	db_printf("\nhardware watchpoints:\n");
698	db_printf("  watch    status        type  len             address\n");
699	db_printf("  -----  --------  ----------  ---  ------------------\n");
700	for (i = 0; i < 4; i++) {
701		if (DBREG_DR7_ENABLED(d.dr[7], i)) {
702			type = DBREG_DR7_ACCESS(d.dr[7], i);
703			len = DBREG_DR7_LEN(d.dr[7], i);
704			if (len == DBREG_DR7_LEN_8)
705				len = 8;
706			else
707				len++;
708			db_printf("  %-5d  %-8s  %10s  %3d  ",
709			    i, "enabled", watchtype_str(type), len);
710			db_printsym((db_addr_t)DBREG_DRX((&d), i), DB_STGY_ANY);
711			db_printf("\n");
712		} else {
713			db_printf("  %-5d  disabled\n", i);
714		}
715	}
716
717	db_printf("\ndebug register values:\n");
718	for (i = 0; i < 8; i++) {
719		db_printf("  dr%d 0x%016lx\n", i, DBREG_DRX((&d), i));
720	}
721	db_printf("\n");
722}
723
724void
725amd64_db_resume_dbreg(void)
726{
727	struct dbreg *d;
728
729	switch (PCPU_GET(dbreg_cmd)) {
730	case PC_DBREG_CMD_LOAD:
731		d = (struct dbreg *)PCPU_PTR(dbreg);
732		set_dbregs(NULL, d);
733		PCPU_SET(dbreg_cmd, PC_DBREG_CMD_NONE);
734		break;
735	}
736}
737