sys/platform/pc64/x86_64/db_trace.c

   1 /*
   2  * Copyright (c) 2008 The DragonFly Project.  All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  *
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in
  12  *    the documentation and/or other materials provided with the
  13  *    distribution.
  14  * 3. Neither the name of The DragonFly Project nor the names of its
  15  *    contributors may be used to endorse or promote products derived
  16  *    from this software without specific, prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  21  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  22  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  23  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  24  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  25  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  26  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  27  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  28  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  *
  31  * --
  32  *
  33  * Mach Operating System
  34  * Copyright (c) 1991,1990 Carnegie Mellon University
  35  * All Rights Reserved.
  36  *
  37  * Permission to use, copy, modify and distribute this software and its
  38  * documentation is hereby granted, provided that both the copyright
  39  * notice and this permission notice appear in all copies of the
  40  * software, derivative works or modified versions, and any portions
  41  * thereof, and that both notices appear in supporting documentation.
  42  *
  43  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
  44  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  45  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  46  *
  47  * Carnegie Mellon requests users of this software to return to
  48  *
  49  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  50  *  School of Computer Science
  51  *  Carnegie Mellon University
  52  *  Pittsburgh PA 15213-3890
  53  *
  54  * any improvements or extensions that they make and grant Carnegie the
  55  * rights to redistribute these changes.
  56  *
  57  * $FreeBSD: src/sys/i386/i386/db_trace.c,v 1.35.2.3 2002/02/21 22:31:25 silby Exp $
  58  */
  59
  60 #include <sys/param.h>
  61 #include <sys/systm.h>
  62 #include <sys/linker_set.h>
  63 #include <sys/lock.h>
  64 #include <sys/proc.h>
  65 #include <sys/reg.h>
  66
  67 #include <machine/cpu.h>
  68 #include <machine/md_var.h>
  69
  70 #include <vm/vm.h>
  71 #include <vm/vm_param.h>
  72 #include <vm/pmap.h>
  73 #include <vm/vm_map.h>
  74 #include <ddb/ddb.h>
  75 #include <dlfcn.h>      /* DLL */
  76
  77 #include <sys/user.h>
  78
  79 #include <ddb/db_access.h>
  80 #include <ddb/db_sym.h>
  81 #include <ddb/db_variables.h>
  82
  83 db_varfcn_t db_dr0;
  84 db_varfcn_t db_dr1;
  85 db_varfcn_t db_dr2;
  86 db_varfcn_t db_dr3;
  87 db_varfcn_t db_dr4;
  88 db_varfcn_t db_dr5;
  89 db_varfcn_t db_dr6;
  90 db_varfcn_t db_dr7;
  91
  92 /*
  93  * Machine register set.
  94  */
  95 struct db_variable db_regs[] = {
  96         { "cs",         &ddb_regs.tf_cs,     NULL },
  97 /*      { "ds",         &ddb_regs.tf_ds,     NULL },
  98         { "es",         &ddb_regs.tf_es,     NULL },
  99         { "fs",         &ddb_regs.tf_fs,     NULL },
 100         { "gs",         &ddb_regs.tf_gs,     NULL }, */
 101         { "ss",         &ddb_regs.tf_ss,     NULL },
 102         { "rax",        &ddb_regs.tf_rax,    NULL },
 103         { "rcx",        &ddb_regs.tf_rcx,    NULL },
 104         { "rdx",        &ddb_regs.tf_rdx,    NULL },
 105         { "rbx",        &ddb_regs.tf_rbx,    NULL },
 106         { "rsp",        &ddb_regs.tf_rsp,    NULL },
 107         { "rbp",        &ddb_regs.tf_rbp,    NULL },
 108         { "rsi",        &ddb_regs.tf_rsi,    NULL },
 109         { "rdi",        &ddb_regs.tf_rdi,    NULL },
 110         { "rip",        &ddb_regs.tf_rip,    NULL },
 111         { "rfl",        &ddb_regs.tf_rflags, NULL },
 112         { "r8",         &ddb_regs.tf_r8,     NULL },
 113         { "r9",         &ddb_regs.tf_r9,     NULL },
 114         { "r10",        &ddb_regs.tf_r10,    NULL },
 115         { "r11",        &ddb_regs.tf_r11,    NULL },
 116         { "r12",        &ddb_regs.tf_r12,    NULL },
 117         { "r13",        &ddb_regs.tf_r13,    NULL },
 118         { "r14",        &ddb_regs.tf_r14,    NULL },
 119         { "r15",        &ddb_regs.tf_r15,    NULL },
 120         { "dr0",        NULL,                db_dr0 },
 121         { "dr1",        NULL,                db_dr1 },
 122         { "dr2",        NULL,                db_dr2 },
 123         { "dr3",        NULL,                db_dr3 },
 124         { "dr4",        NULL,                db_dr4 },
 125         { "dr5",        NULL,                db_dr5 },
 126         { "dr6",        NULL,                db_dr6 },
 127         { "dr7",        NULL,                db_dr7 },
 128 };
 129 struct db_variable *db_eregs = db_regs + sizeof(db_regs)/sizeof(db_regs[0]);
 130
 131 /*
 132  * Stack trace.
 133  */
 134 #define INKERNEL(va)    (((vm_offset_t)(va)) >= USRSTACK)
 135
 136 struct x86_64_frame {
 137         struct x86_64_frame     *f_frame;
 138         long                    f_retaddr;
 139         long                    f_arg0;
 140 };
 141
 142 #define NORMAL          0
 143 #define TRAP            1
 144 #define INTERRUPT       2
 145 #define SYSCALL         3
 146
 147 static void     db_nextframe(struct x86_64_frame **, db_addr_t *);
 148 static int      db_numargs(struct x86_64_frame *);
 149 static void     db_print_stack_entry(const char *, int, char **, long *, db_addr_t);
 150 static void     dl_symbol_values(long callpc, const char **name);
 151
 152
 153 static char     *watchtype_str(int type);
 154 static int      kx86_64_set_watch(int watchnum, unsigned int watchaddr,
 155                                int size, int access, struct dbreg * d);
 156 static int      kx86_64_clr_watch(int watchnum, struct dbreg * d);
 157 int             db_md_set_watchpoint(db_expr_t addr, db_expr_t size);
 158 int             db_md_clr_watchpoint(db_expr_t addr, db_expr_t size);
 159 void            db_md_list_watchpoints(void);
 160
 161
 162 /*
 163  * Figure out how many arguments were passed into the frame at "fp".
 164  */
 165 static int
 166 db_numargs(struct x86_64_frame *fp)
 167 {
 168 #if 1
 169         return (0);     /* regparm, needs dwarf2 info */
 170 #else
 171         int     args;
 172 #if 0
 173         int     *argp;
 174         int     inst;
 175
 176         argp = (int *)db_get_value((int)&fp->f_retaddr, 4, FALSE);
 177         /*
 178          * XXX etext is wrong for LKMs.  We should attempt to interpret
 179          * the instruction at the return address in all cases.  This
 180          * may require better fault handling.
 181          */
 182         if (argp < (int *)btext || argp >= (int *)etext) {
 183                 args = 5;
 184         } else {
 185                 inst = db_get_value((int)argp, 4, FALSE);
 186                 if ((inst & 0xff) == 0x59)      /* popl %ecx */
 187                         args = 1;
 188                 else if ((inst & 0xffff) == 0xc483)     /* addl $Ibs, %esp */
 189                         args = ((inst >> 16) & 0xff) / 4;
 190                 else
 191                         args = 5;
 192         }
 193 #endif
 194         args = 5;
 195         return(args);
 196 #endif
 197 }
 198
 199 static void
 200 db_print_stack_entry(const char *name, int narg, char **argnp, long *argp,
 201                      db_addr_t callpc)
 202 {
 203         db_printf("%s(", name);
 204         while (narg) {
 205                 if (argnp)
 206                         db_printf("%s=", *argnp++);
 207                 db_printf("%ld", (long)db_get_value((long)argp, 8, FALSE));
 208                 argp++;
 209                 if (--narg != 0)
 210                         db_printf(",");
 211         }
 212         db_printf(") at ");
 213         db_printsym(callpc, DB_STGY_PROC);
 214         db_printf("\n");
 215 }
 216
 217 /*
 218  * Figure out the next frame up in the call stack.
 219  */
 220 static void
 221 db_nextframe(struct x86_64_frame **fp, db_addr_t *ip)
 222 {
 223         struct trapframe *tf;
 224         int frame_type;
 225         long rip, rsp, rbp;
 226         db_expr_t offset;
 227         const char *sym, *name;
 228
 229         if ((unsigned long)*fp < PAGE_SIZE) {
 230                 *fp = NULL;
 231                 return;
 232         }
 233         rip = db_get_value((long) &(*fp)->f_retaddr, 8, FALSE);
 234         rbp = db_get_value((long) &(*fp)->f_frame, 8, FALSE);
 235
 236         /*
 237          * Figure out frame type.
 238          */
 239
 240         frame_type = NORMAL;
 241
 242         sym = db_search_symbol(rip, DB_STGY_ANY, &offset);
 243         db_symbol_values(sym, &name, NULL);
 244         dl_symbol_values(rip, &name);
 245         if (name != NULL) {
 246                 if (!strcmp(name, "calltrap")) {
 247                         frame_type = TRAP;
 248                 } else if (!strncmp(name, "Xresume", 7)) {
 249                         frame_type = INTERRUPT;
 250                 } else if (!strcmp(name, "_Xsyscall")) {
 251                         frame_type = SYSCALL;
 252                 }
 253         }
 254
 255         /*
 256          * Normal frames need no special processing.
 257          */
 258         if (frame_type == NORMAL) {
 259                 *ip = (db_addr_t) rip;
 260                 *fp = (struct x86_64_frame *) rbp;
 261                 return;
 262         }
 263
 264         db_print_stack_entry(name, 0, 0, 0, rip);
 265
 266         /*
 267          * Point to base of trapframe which is just above the
 268          * current frame.
 269          */
 270         tf = (struct trapframe *)((long)*fp + 16);
 271
 272 #if 0
 273         rsp = (ISPL(tf->tf_cs) == SEL_UPL) ?  tf->tf_rsp : (long)&tf->tf_rsp;
 274 #endif
 275         rsp = (long)&tf->tf_rsp;
 276
 277         switch (frame_type) {
 278         case TRAP:
 279                 {
 280                         rip = tf->tf_rip;
 281                         rbp = tf->tf_rbp;
 282                         db_printf(
 283             "--- trap %016lx, rip = %016lx, rsp = %016lx, rbp = %016lx ---\n",
 284                             tf->tf_trapno, rip, rsp, rbp);
 285                 }
 286                 break;
 287         case SYSCALL:
 288                 {
 289                         rip = tf->tf_rip;
 290                         rbp = tf->tf_rbp;
 291                         db_printf(
 292         "--- syscall %016lx, rip = %016lx, rsp = %016lx, rbp = %016lx ---\n",
 293                             tf->tf_rax, rip, rsp, rbp);
 294                 }
 295                 break;
 296         case INTERRUPT:
 297                 tf = (struct trapframe *)((long)*fp + 16);
 298                 {
 299                         rip = tf->tf_rip;
 300                         rbp = tf->tf_rbp;
 301                         db_printf(
 302             "--- interrupt, rip = %016lx, rsp = %016lx, rbp = %016lx ---\n",
 303                             rip, rsp, rbp);
 304                 }
 305                 break;
 306         default:
 307                 rip = tf->tf_rip;
 308                 rbp = tf->tf_rbp;
 309                 break;
 310         }
 311
 312         *ip = (db_addr_t) rip;
 313         *fp = (struct x86_64_frame *) rbp;
 314 }
 315
 316 void
 317 db_stack_trace_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count,
 318                    char *modif)
 319 {
 320         struct x86_64_frame *frame;
 321         long *argp;
 322         db_addr_t callpc;
 323         boolean_t first;
 324         int i;
 325
 326         if (count == -1)
 327                 count = 1024;
 328
 329         if (!have_addr) {
 330                 frame = (struct x86_64_frame *)BP_REGS(&ddb_regs);
 331                 if (frame == NULL)
 332                         frame = (struct x86_64_frame *)(SP_REGS(&ddb_regs) - 8);
 333                 callpc = PC_REGS(&ddb_regs);
 334         } else {
 335                 /*
 336                  * Look for something that might be a frame pointer, just as
 337                  * a convenience.
 338                  */
 339                 frame = (struct x86_64_frame *)addr;
 340                 for (i = 0; i < 4096; i += 8) {
 341                         struct x86_64_frame *check;
 342
 343                         check = (struct x86_64_frame *)db_get_value((long)((char *)&frame->f_frame + i), 8, FALSE);
 344                         if ((char *)check - (char *)frame >= 0 &&
 345                             (char *)check - (char *)frame < 4096
 346                         ) {
 347                                 break;
 348                         }
 349                         db_printf("%p does not look like a stack frame, skipping\n", (char *)&frame->f_frame + i);
 350                 }
 351                 if (i == 4096) {
 352                         db_printf("Unable to find anything that looks like a stack frame\n");
 353                         return;
 354                 }
 355                 frame = (void *)((char *)frame + i);
 356                 db_printf("Trace beginning at frame %p\n", frame);
 357                 callpc = (db_addr_t)db_get_value((long)&frame->f_retaddr, 8, FALSE);
 358         }
 359
 360         first = TRUE;
 361         while (count--) {
 362                 struct x86_64_frame *actframe;
 363                 int             narg;
 364                 const char *    name;
 365                 db_expr_t       offset;
 366                 c_db_sym_t      sym;
 367 #define MAXNARG 16
 368                 char    *argnames[MAXNARG], **argnp = NULL;
 369
 370                 sym = db_search_symbol(callpc, DB_STGY_ANY, &offset);
 371                 db_symbol_values(sym, &name, NULL);
 372                 dl_symbol_values(callpc, &name);
 373
 374                 /*
 375                  * Attempt to determine a (possibly fake) frame that gives
 376                  * the caller's pc.  It may differ from `frame' if the
 377                  * current function never sets up a standard frame or hasn't
 378                  * set one up yet or has just discarded one.  The last two
 379                  * cases can be guessed fairly reliably for code generated
 380                  * by gcc.  The first case is too much trouble to handle in
 381                  * general because the amount of junk on the stack depends
 382                  * on the pc (the special handling of "calltrap", etc. in
 383                  * db_nextframe() works because the `next' pc is special).
 384                  */
 385                 actframe = frame;
 386                 if (first) {
 387                         if (!have_addr) {
 388                                 int instr;
 389
 390                                 instr = db_get_value(callpc, 4, FALSE);
 391                                 if ((instr & 0xffffffff) == 0xe5894855) {
 392                                         /* pushq %rbp; movq %rsp, %rbp */
 393                                         actframe = (struct x86_64_frame *)
 394                                             (SP_REGS(&ddb_regs) - 8);
 395                                 } else if ((instr & 0xffffff) == 0xe58948) {
 396                                         /* movq %rsp, %rbp */
 397                                         actframe = (struct x86_64_frame *)
 398                                             SP_REGS(&ddb_regs);
 399                                         if (ddb_regs.tf_rbp == 0) {
 400                                                 /* Fake caller's frame better. */
 401                                                 frame = actframe;
 402                                         }
 403                                 } else if ((instr & 0xff) == 0xc3) {
 404                                         /* ret */
 405                                         actframe = (struct x86_64_frame *)
 406                                             (SP_REGS(&ddb_regs) - 8);
 407                                 } else if (offset == 0) {
 408                                         /* Probably a symbol in assembler code. */
 409                                         actframe = (struct x86_64_frame *)
 410                                             (SP_REGS(&ddb_regs) - 8);
 411                                 }
 412                         } else if (name != NULL &&
 413                                    strcmp(name, "fork_trampoline") == 0) {
 414                                 /*
 415                                  * Don't try to walk back on a stack for a
 416                                  * process that hasn't actually been run yet.
 417                                  */
 418                                 db_print_stack_entry(name, 0, 0, 0, callpc);
 419                                 break;
 420                         }
 421                         first = FALSE;
 422                 }
 423
 424                 argp = &actframe->f_arg0;
 425                 narg = MAXNARG;
 426                 if (sym != NULL && db_sym_numargs(sym, &narg, argnames)) {
 427                         argnp = argnames;
 428                 } else {
 429                         narg = db_numargs(frame);
 430                 }
 431
 432                 db_print_stack_entry(name, narg, argnp, argp, callpc);
 433
 434                 if (actframe != frame) {
 435                         /* `frame' belongs to caller. */
 436                         callpc = (db_addr_t)
 437                             db_get_value((long)&actframe->f_retaddr, 8, FALSE);
 438                         continue;
 439                 }
 440
 441                 db_nextframe(&frame, &callpc);
 442                 if (frame == 0)
 443                         break;
 444         }
 445 }
 446
 447 void
 448 print_backtrace(void)
 449 {
 450         register_t  rbp;
 451
 452         __asm __volatile("movq %%rbp, %0" : "=r" (rbp));
 453         db_stack_trace_cmd(rbp, 1, -1, NULL);
 454 }
 455
 456 #define DB_DRX_FUNC(reg)                                                \
 457 int                                                                     \
 458 db_ ## reg (struct db_variable *vp, db_expr_t *valuep, int op)          \
 459 {                                                                       \
 460         if (op == DB_VAR_GET)                                           \
 461                 *valuep = r ## reg ();                                  \
 462         else                                                            \
 463                 load_ ## reg (*valuep);                                 \
 464                                                                         \
 465         return(0);                                                      \
 466 }
 467
 468 DB_DRX_FUNC(dr0)
 469 DB_DRX_FUNC(dr1)
 470 DB_DRX_FUNC(dr2)
 471 DB_DRX_FUNC(dr3)
 472 DB_DRX_FUNC(dr4)
 473 DB_DRX_FUNC(dr5)
 474 DB_DRX_FUNC(dr6)
 475 DB_DRX_FUNC(dr7)
 476
 477 static int
 478 kx86_64_set_watch(int watchnum, unsigned int watchaddr, int size, int access,
 479                struct dbreg *d)
 480 {
 481         int i;
 482         unsigned int mask;
 483
 484         if (watchnum == -1) {
 485                 for (i = 0, mask = 0x3; i < 4; i++, mask <<= 2)
 486                         if ((d->dr[7] & mask) == 0)
 487                                 break;
 488                 if (i < 4)
 489                         watchnum = i;
 490                 else
 491                         return(-1);
 492         }
 493
 494         switch (access) {
 495         case DBREG_DR7_EXEC:
 496                 size = 1; /* size must be 1 for an execution breakpoint */
 497                 /* fall through */
 498         case DBREG_DR7_WRONLY:
 499         case DBREG_DR7_RDWR:
 500                 break;
 501         default:
 502                 return(-1);
 503         }
 504
 505         /*
 506          * we can watch a 1, 2, 4, or 8 byte sized location
 507          */
 508         switch (size) {
 509         case 1:
 510                 mask = 0x00;
 511                 break;
 512         case 2:
 513                 mask = 0x01 << 2;
 514                 break;
 515         case 4:
 516                 mask = 0x03 << 2;
 517         case 8:
 518                 mask = 0x02 << 2;
 519                 break;
 520         default:
 521                 return(-1);
 522         }
 523
 524         mask |= access;
 525
 526         /* clear the bits we are about to affect */
 527         d->dr[7] &= ~((0x3 << (watchnum * 2)) | (0x0f << (watchnum * 4 + 16)));
 528
 529         /* set drN register to the address, N=watchnum */
 530         DBREG_DRX(d, watchnum) = watchaddr;
 531
 532         /* enable the watchpoint */
 533         d->dr[7] |= (0x2 << (watchnum * 2)) | (mask << (watchnum * 4 + 16));
 534
 535         return(watchnum);
 536 }
 537
 538
 539 int
 540 kx86_64_clr_watch(int watchnum, struct dbreg *d)
 541 {
 542         if (watchnum < 0 || watchnum >= 4)
 543                 return(-1);
 544
 545         d->dr[7] &= ~((0x3 << (watchnum * 2)) | (0x0f << (watchnum * 4 + 16)));
 546         DBREG_DRX(d, watchnum) = 0;
 547
 548         return(0);
 549 }
 550
 551
 552 int
 553 db_md_set_watchpoint(db_expr_t addr, db_expr_t size)
 554 {
 555         int avail, wsize;
 556         int i;
 557         struct dbreg d;
 558
 559         fill_dbregs(NULL, &d);
 560
 561         avail = 0;
 562         for (i = 0; i < 4; i++) {
 563                 if ((d.dr[7] & (3 << (i * 2))) == 0)
 564                         avail++;
 565         }
 566
 567         if (avail * 8 < size)
 568                 return(-1);
 569
 570         for (i=0; i < 4 && (size != 0); i++) {
 571                 if ((d.dr[7] & (3 << (i * 2))) == 0) {
 572                         if (size >= 8 || (avail == 1 && size > 4))
 573                                 wsize = 8;
 574                         else if (size > 2)
 575                                 wsize = 4;
 576                         else
 577                                 wsize = size;
 578                         if (wsize == 3)
 579                                 wsize++;
 580                         kx86_64_set_watch(i, addr, wsize, DBREG_DR7_WRONLY, &d);
 581                         addr += wsize;
 582                         size -= wsize;
 583                 }
 584         }
 585
 586         set_dbregs(NULL, &d);
 587
 588         return(0);
 589 }
 590
 591 int
 592 db_md_clr_watchpoint(db_expr_t addr, db_expr_t size)
 593 {
 594         struct dbreg d;
 595         int i;
 596
 597         fill_dbregs(NULL, &d);
 598
 599         for(i = 0; i < 4; i++) {
 600                 if (d.dr[7] & (3 << (i * 2))) {
 601                         if ((DBREG_DRX((&d), i) >= addr) &&
 602                             (DBREG_DRX((&d), i) < addr + size))
 603                                 kx86_64_clr_watch(i, &d);
 604                 }
 605         }
 606
 607         set_dbregs(NULL, &d);
 608
 609         return(0);
 610 }
 611
 612 static char *
 613 watchtype_str(int type)
 614 {
 615         switch (type) {
 616         case DBREG_DR7_EXEC:
 617                 return "execute";
 618         case DBREG_DR7_RDWR:
 619                 return "read/write";
 620         case DBREG_DR7_WRONLY:
 621                 return "write";
 622         default:
 623                 return "invalid";
 624         }
 625 }
 626
 627 void
 628 db_md_list_watchpoints(void)
 629 {
 630         int i;
 631         struct dbreg d;
 632
 633         fill_dbregs(NULL, &d);
 634
 635         db_printf("\nhardware watchpoints:\n");
 636         db_printf("  watch    status        type  len     address\n"
 637                   "  -----  --------  ----------  ---  ----------\n");
 638         for (i = 0; i < 4; i++) {
 639                 if (d.dr[7] & (0x03 << (i * 2))) {
 640                         unsigned type, len;
 641                         type = (d.dr[7] >> (16 + (i * 4))) & 3;
 642                         len =  (d.dr[7] >> (16 + (i * 4) + 2)) & 3;
 643                         db_printf("  %-5d  %-8s  %10s  %3d  0x%08lx\n",
 644                                   i, "enabled", watchtype_str(type),
 645                                   len + 1, DBREG_DRX((&d), i));
 646                 } else {
 647                         db_printf("  %-5d  disabled\n", i);
 648                 }
 649         }
 650
 651         db_printf("\ndebug register values:\n");
 652         for (i = 0; i < 8; i++)
 653                 db_printf("  dr%d 0x%08lx\n", i, DBREG_DRX((&d),i));
 654         db_printf("\n");
 655 }
 656
 657 /*
 658  * See if dladdr() can get the symbol name via the standard dynamic loader.
 659  */
 660 static
 661 void
 662 dl_symbol_values(long callpc, const char **name)
 663 {
 664 #if 0
 665         Dl_info info;
 666         if (*name == NULL) {
 667                 if (dladdr((const void *)callpc, &info) != 0) {
 668                         if (info.dli_saddr <= (const void *)callpc)
 669                                 *name = info.dli_sname;
 670                 }
 671         }
 672 #endif
 673 }
 674