The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/i386/i386/db_trace.c

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    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: releng/6.2/sys/i386/i386/db_trace.c 161320 2006-08-15 15:59:25Z yar $");
   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         { "dr0",        NULL,                   db_dr0 },
   84         { "dr1",        NULL,                   db_dr1 },
   85         { "dr2",        NULL,                   db_dr2 },
   86         { "dr3",        NULL,                   db_dr3 },
   87         { "dr4",        NULL,                   db_dr4 },
   88         { "dr5",        NULL,                   db_dr5 },
   89         { "dr6",        NULL,                   db_dr6 },
   90         { "dr7",        NULL,                   db_dr7 },
   91 };
   92 struct db_variable *db_eregs = db_regs + sizeof(db_regs)/sizeof(db_regs[0]);
   93 
   94 #define DB_DRX_FUNC(reg)                \
   95 static int                              \
   96 db_ ## reg (vp, valuep, op)             \
   97         struct db_variable *vp;         \
   98         db_expr_t * valuep;             \
   99         int op;                         \
  100 {                                       \
  101         if (op == DB_VAR_GET)           \
  102                 *valuep = r ## reg ();  \
  103         else                            \
  104                 load_ ## reg (*valuep); \
  105         return (1);                     \
  106 }
  107 
  108 DB_DRX_FUNC(dr0)
  109 DB_DRX_FUNC(dr1)
  110 DB_DRX_FUNC(dr2)
  111 DB_DRX_FUNC(dr3)
  112 DB_DRX_FUNC(dr4)
  113 DB_DRX_FUNC(dr5)
  114 DB_DRX_FUNC(dr6)
  115 DB_DRX_FUNC(dr7)
  116 
  117 static __inline int
  118 get_esp(struct trapframe *tf)
  119 {
  120         return ((ISPL(tf->tf_cs)) ? tf->tf_esp :
  121             (db_expr_t)tf + (uintptr_t)DB_OFFSET(tf_esp));
  122 }
  123 
  124 static int
  125 db_frame(struct db_variable *vp, db_expr_t *valuep, int op)
  126 {
  127         int *reg;
  128 
  129         if (kdb_frame == NULL)
  130                 return (0);
  131 
  132         reg = (int *)((uintptr_t)kdb_frame + (db_expr_t)vp->valuep);
  133         if (op == DB_VAR_GET)
  134                 *valuep = *reg;
  135         else
  136                 *reg = *valuep;
  137         return (1);
  138 }
  139 
  140 static int
  141 db_esp(struct db_variable *vp, db_expr_t *valuep, int op)
  142 {
  143 
  144         if (kdb_frame == NULL)
  145                 return (0);
  146 
  147         if (op == DB_VAR_GET)
  148                 *valuep = get_esp(kdb_frame);
  149         else if (ISPL(kdb_frame->tf_cs))
  150                 kdb_frame->tf_esp = *valuep;
  151         return (1);
  152 }
  153 
  154 static int
  155 db_ss(struct db_variable *vp, db_expr_t *valuep, int op)
  156 {
  157 
  158         if (kdb_frame == NULL)
  159                 return (0);
  160 
  161         if (op == DB_VAR_GET)
  162                 *valuep = (ISPL(kdb_frame->tf_cs)) ? kdb_frame->tf_ss : rss();
  163         else if (ISPL(kdb_frame->tf_cs))
  164                 kdb_frame->tf_ss = *valuep;
  165         return (1);
  166 }
  167 
  168 /*
  169  * Stack trace.
  170  */
  171 #define INKERNEL(va)    (((vm_offset_t)(va)) >= USRSTACK && \
  172             ((vm_offset_t)(va)) < VM_MAX_KERNEL_ADDRESS)
  173 
  174 struct i386_frame {
  175         struct i386_frame       *f_frame;
  176         int                     f_retaddr;
  177         int                     f_arg0;
  178 };
  179 
  180 #define NORMAL          0
  181 #define TRAP            1
  182 #define INTERRUPT       2
  183 #define SYSCALL         3
  184 #define DOUBLE_FAULT    4
  185 
  186 static void db_nextframe(struct i386_frame **, db_addr_t *, struct thread *);
  187 static int db_numargs(struct i386_frame *);
  188 static void db_print_stack_entry(const char *, int, char **, int *, db_addr_t);
  189 static void decode_syscall(int, struct thread *);
  190 
  191 static char * watchtype_str(int type);
  192 int  i386_set_watch(int watchnum, unsigned int watchaddr, int size, int access,
  193                     struct dbreg * d);
  194 int  i386_clr_watch(int watchnum, struct dbreg * d);
  195 int  db_md_set_watchpoint(db_expr_t addr, db_expr_t size);
  196 int  db_md_clr_watchpoint(db_expr_t addr, db_expr_t size);
  197 void db_md_list_watchpoints(void);
  198 
  199 /*
  200  * Figure out how many arguments were passed into the frame at "fp".
  201  */
  202 static int
  203 db_numargs(fp)
  204         struct i386_frame *fp;
  205 {
  206         char   *argp;
  207         int     inst;
  208         int     args;
  209 
  210         argp = (char *)db_get_value((int)&fp->f_retaddr, 4, FALSE);
  211         /*
  212          * XXX etext is wrong for LKMs.  We should attempt to interpret
  213          * the instruction at the return address in all cases.  This
  214          * may require better fault handling.
  215          */
  216         if (argp < btext || argp >= etext) {
  217                 args = -1;
  218         } else {
  219 retry:
  220                 inst = db_get_value((int)argp, 4, FALSE);
  221                 if ((inst & 0xff) == 0x59)      /* popl %ecx */
  222                         args = 1;
  223                 else if ((inst & 0xffff) == 0xc483)     /* addl $Ibs, %esp */
  224                         args = ((inst >> 16) & 0xff) / 4;
  225                 else if ((inst & 0xf8ff) == 0xc089) {   /* movl %eax, %Reg */
  226                         argp += 2;
  227                         goto retry;
  228                 } else
  229                         args = -1;
  230         }
  231         return (args);
  232 }
  233 
  234 static void
  235 db_print_stack_entry(name, narg, argnp, argp, callpc)
  236         const char *name;
  237         int narg;
  238         char **argnp;
  239         int *argp;
  240         db_addr_t callpc;
  241 {
  242         int n = narg >= 0 ? narg : 5;
  243 
  244         db_printf("%s(", name);
  245         while (n) {
  246                 if (argnp)
  247                         db_printf("%s=", *argnp++);
  248                 db_printf("%r", db_get_value((int)argp, 4, FALSE));
  249                 argp++;
  250                 if (--n != 0)
  251                         db_printf(",");
  252         }
  253         if (narg < 0)
  254                 db_printf(",...");
  255         db_printf(") at ");
  256         db_printsym(callpc, DB_STGY_PROC);
  257         db_printf("\n");
  258 }
  259 
  260 static void
  261 decode_syscall(int number, struct thread *td)
  262 {
  263         struct proc *p;
  264         c_db_sym_t sym;
  265         db_expr_t diff;
  266         sy_call_t *f;
  267         const char *symname;
  268 
  269         db_printf(" (%d", number);
  270         p = (td != NULL) ? td->td_proc : NULL;
  271         if (p != NULL && 0 <= number && number < p->p_sysent->sv_size) {
  272                 f = p->p_sysent->sv_table[number].sy_call;
  273                 sym = db_search_symbol((db_addr_t)f, DB_STGY_ANY, &diff);
  274                 if (sym != DB_SYM_NULL && diff == 0) {
  275                         db_symbol_values(sym, &symname, NULL);
  276                         db_printf(", %s, %s", p->p_sysent->sv_name, symname);
  277                 }
  278         }
  279         db_printf(")");
  280 }
  281 
  282 /*
  283  * Figure out the next frame up in the call stack.
  284  */
  285 static void
  286 db_nextframe(struct i386_frame **fp, db_addr_t *ip, struct thread *td)
  287 {
  288         struct trapframe *tf;
  289         int frame_type;
  290         int eip, esp, ebp;
  291         db_expr_t offset;
  292         c_db_sym_t sym;
  293         const char *name;
  294 
  295         eip = db_get_value((int) &(*fp)->f_retaddr, 4, FALSE);
  296         ebp = db_get_value((int) &(*fp)->f_frame, 4, FALSE);
  297 
  298         /*
  299          * Figure out frame type.  We look at the address just before
  300          * the saved instruction pointer as the saved EIP is after the
  301          * call function, and if the function being called is marked as
  302          * dead (such as panic() at the end of dblfault_handler()), then
  303          * the instruction at the saved EIP will be part of a different
  304          * function (syscall() in this example) rather than the one that
  305          * actually made the call.
  306          */
  307         frame_type = NORMAL;
  308         sym = db_search_symbol(eip - 1, DB_STGY_ANY, &offset);
  309         db_symbol_values(sym, &name, NULL);
  310         if (name != NULL) {
  311                 if (strcmp(name, "calltrap") == 0 ||
  312                     strcmp(name, "fork_trampoline") == 0)
  313                         frame_type = TRAP;
  314                 else if (strncmp(name, "Xatpic_intr", 11) == 0 ||
  315                     strncmp(name, "Xapic_isr", 9) == 0)
  316                         frame_type = INTERRUPT;
  317                 else if (strcmp(name, "Xlcall_syscall") == 0 ||
  318                     strcmp(name, "Xint0x80_syscall") == 0)
  319                         frame_type = SYSCALL;
  320                 else if (strcmp(name, "dblfault_handler") == 0)
  321                         frame_type = DOUBLE_FAULT;
  322         }
  323 
  324         /*
  325          * Normal frames need no special processing.
  326          */
  327         if (frame_type == NORMAL) {
  328                 *ip = (db_addr_t) eip;
  329                 *fp = (struct i386_frame *) ebp;
  330                 return;
  331         }
  332 
  333         db_print_stack_entry(name, 0, 0, 0, eip);
  334 
  335         /*
  336          * For a double fault, we have to snag the values from the
  337          * previous TSS since a double fault uses a task gate to
  338          * switch to a known good state.
  339          */
  340         if (frame_type == DOUBLE_FAULT) {
  341                 esp = PCPU_GET(common_tss.tss_esp);
  342                 eip = PCPU_GET(common_tss.tss_eip);
  343                 ebp = PCPU_GET(common_tss.tss_ebp);
  344                 db_printf(
  345                     "--- trap 0x17, eip = %#r, esp = %#r, ebp = %#r ---\n",
  346                     eip, esp, ebp);
  347                 *ip = (db_addr_t) eip;
  348                 *fp = (struct i386_frame *) ebp;
  349                 return;
  350         }
  351 
  352         /*
  353          * Point to base of trapframe which is just above the
  354          * current frame.
  355          */
  356         if (frame_type == INTERRUPT)
  357                 tf = (struct trapframe *)((int)*fp + 12);
  358         else
  359                 tf = (struct trapframe *)((int)*fp + 8);
  360 
  361         if (INKERNEL((int) tf)) {
  362                 esp = get_esp(tf);
  363                 eip = tf->tf_eip;
  364                 ebp = tf->tf_ebp;
  365                 switch (frame_type) {
  366                 case TRAP:
  367                         db_printf("--- trap %#r", tf->tf_trapno);
  368                         break;
  369                 case SYSCALL:
  370                         db_printf("--- syscall");
  371                         decode_syscall(tf->tf_eax, td);
  372                         break;
  373                 case INTERRUPT:
  374                         db_printf("--- interrupt");
  375                         break;
  376                 default:
  377                         panic("The moon has moved again.");
  378                 }
  379                 db_printf(", eip = %#r, esp = %#r, ebp = %#r ---\n", eip,
  380                     esp, ebp);
  381         }
  382 
  383         *ip = (db_addr_t) eip;
  384         *fp = (struct i386_frame *) ebp;
  385 }
  386 
  387 static int
  388 db_backtrace(struct thread *td, struct trapframe *tf, struct i386_frame *frame,
  389     db_addr_t pc, int count)
  390 {
  391         struct i386_frame *actframe;
  392 #define MAXNARG 16
  393         char *argnames[MAXNARG], **argnp = NULL;
  394         const char *name;
  395         int *argp;
  396         db_expr_t offset;
  397         c_db_sym_t sym;
  398         int narg, quit;
  399         boolean_t first;
  400 
  401         if (count == -1)
  402                 count = 1024;
  403 
  404         first = TRUE;
  405         quit = 0;
  406         db_setup_paging(db_simple_pager, &quit, db_lines_per_page);
  407         while (count-- && !quit) {
  408                 sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
  409                 db_symbol_values(sym, &name, NULL);
  410 
  411                 /*
  412                  * Attempt to determine a (possibly fake) frame that gives
  413                  * the caller's pc.  It may differ from `frame' if the
  414                  * current function never sets up a standard frame or hasn't
  415                  * set one up yet or has just discarded one.  The last two
  416                  * cases can be guessed fairly reliably for code generated
  417                  * by gcc.  The first case is too much trouble to handle in
  418                  * general because the amount of junk on the stack depends
  419                  * on the pc (the special handling of "calltrap", etc. in
  420                  * db_nextframe() works because the `next' pc is special).
  421                  */
  422                 actframe = frame;
  423                 if (first) {
  424                         if (tf != NULL) {
  425                                 int instr;
  426 
  427                                 instr = db_get_value(pc, 4, FALSE);
  428                                 if ((instr & 0xffffff) == 0x00e58955) {
  429                                         /* pushl %ebp; movl %esp, %ebp */
  430                                         actframe = (void *)(get_esp(tf) - 4);
  431                                 } else if ((instr & 0xffff) == 0x0000e589) {
  432                                         /* movl %esp, %ebp */
  433                                         actframe = (void *)get_esp(tf);
  434                                         if (tf->tf_ebp == 0) {
  435                                                 /* Fake frame better. */
  436                                                 frame = actframe;
  437                                         }
  438                                 } else if ((instr & 0xff) == 0x000000c3) {
  439                                         /* ret */
  440                                         actframe = (void *)(get_esp(tf) - 4);
  441                                 } else if (offset == 0) {
  442                                         /* Probably an assembler symbol. */
  443                                         actframe = (void *)(get_esp(tf) - 4);
  444                                 }
  445                         } else if (strcmp(name, "fork_trampoline") == 0) {
  446                                 /*
  447                                  * Don't try to walk back on a stack for a
  448                                  * process that hasn't actually been run yet.
  449                                  */
  450                                 db_print_stack_entry(name, 0, 0, 0, pc);
  451                                 break;
  452                         }
  453                         first = FALSE;
  454                 }
  455 
  456                 argp = &actframe->f_arg0;
  457                 narg = MAXNARG;
  458                 if (sym != NULL && db_sym_numargs(sym, &narg, argnames)) {
  459                         argnp = argnames;
  460                 } else {
  461                         narg = db_numargs(frame);
  462                 }
  463 
  464                 db_print_stack_entry(name, narg, argnp, argp, pc);
  465 
  466                 if (actframe != frame) {
  467                         /* `frame' belongs to caller. */
  468                         pc = (db_addr_t)
  469                             db_get_value((int)&actframe->f_retaddr, 4, FALSE);
  470                         continue;
  471                 }
  472 
  473                 db_nextframe(&frame, &pc, td);
  474 
  475                 if (INKERNEL((int)pc) && !INKERNEL((int) frame)) {
  476                         sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
  477                         db_symbol_values(sym, &name, NULL);
  478                         db_print_stack_entry(name, 0, 0, 0, pc);
  479                         break;
  480                 }
  481                 if (!INKERNEL((int) frame)) {
  482                         break;
  483                 }
  484         }
  485 
  486         return (0);
  487 }
  488 
  489 void
  490 db_trace_self(void)
  491 {
  492         struct i386_frame *frame;
  493         db_addr_t callpc;
  494         register_t ebp;
  495 
  496         __asm __volatile("movl %%ebp,%0" : "=r" (ebp));
  497         frame = (struct i386_frame *)ebp;
  498         callpc = (db_addr_t)db_get_value((int)&frame->f_retaddr, 4, FALSE);
  499         frame = frame->f_frame;
  500         db_backtrace(curthread, NULL, frame, callpc, -1);
  501 }
  502 
  503 int
  504 db_trace_thread(struct thread *thr, int count)
  505 {
  506         struct pcb *ctx;
  507 
  508         ctx = kdb_thr_ctx(thr);
  509         return (db_backtrace(thr, NULL, (struct i386_frame *)ctx->pcb_ebp,
  510                     ctx->pcb_eip, count));
  511 }
  512 
  513 void
  514 stack_save(struct stack *st)
  515 {
  516         struct i386_frame *frame;
  517         vm_offset_t callpc;
  518         register_t ebp;
  519 
  520         stack_zero(st);
  521         __asm __volatile("movl %%ebp,%0" : "=r" (ebp));
  522         frame = (struct i386_frame *)ebp;
  523         while (1) {
  524                 if (!INKERNEL(frame))
  525                         break;
  526                 callpc = frame->f_retaddr;
  527                 if (!INKERNEL(callpc))
  528                         break;
  529                 if (stack_put(st, callpc) == -1)
  530                         break;
  531                 if (frame->f_frame <= frame ||
  532                     (vm_offset_t)frame->f_frame >=
  533                     (vm_offset_t)ebp + KSTACK_PAGES * PAGE_SIZE)
  534                         break;
  535                 frame = frame->f_frame;
  536         }
  537 }
  538 
  539 int
  540 i386_set_watch(watchnum, watchaddr, size, access, d)
  541         int watchnum;
  542         unsigned int watchaddr;
  543         int size;
  544         int access;
  545         struct dbreg * d;
  546 {
  547         int i;
  548         unsigned int mask;
  549         
  550         if (watchnum == -1) {
  551                 for (i = 0, mask = 0x3; i < 4; i++, mask <<= 2)
  552                         if ((d->dr[7] & mask) == 0)
  553                                 break;
  554                 if (i < 4)
  555                         watchnum = i;
  556                 else
  557                         return (-1);
  558         }
  559         
  560         switch (access) {
  561         case DBREG_DR7_EXEC:
  562                 size = 1; /* size must be 1 for an execution breakpoint */
  563                 /* fall through */
  564         case DBREG_DR7_WRONLY:
  565         case DBREG_DR7_RDWR:
  566                 break;
  567         default : return (-1);
  568         }
  569         
  570         /*
  571          * we can watch a 1, 2, or 4 byte sized location
  572          */
  573         switch (size) {
  574         case 1  : mask = 0x00; break;
  575         case 2  : mask = 0x01 << 2; break;
  576         case 4  : mask = 0x03 << 2; break;
  577         default : return (-1);
  578         }
  579 
  580         mask |= access;
  581 
  582         /* clear the bits we are about to affect */
  583         d->dr[7] &= ~((0x3 << (watchnum*2)) | (0x0f << (watchnum*4+16)));
  584 
  585         /* set drN register to the address, N=watchnum */
  586         DBREG_DRX(d,watchnum) = watchaddr;
  587 
  588         /* enable the watchpoint */
  589         d->dr[7] |= (0x2 << (watchnum*2)) | (mask << (watchnum*4+16));
  590 
  591         return (watchnum);
  592 }
  593 
  594 
  595 int
  596 i386_clr_watch(watchnum, d)
  597         int watchnum;
  598         struct dbreg * d;
  599 {
  600 
  601         if (watchnum < 0 || watchnum >= 4)
  602                 return (-1);
  603         
  604         d->dr[7] = d->dr[7] & ~((0x3 << (watchnum*2)) | (0x0f << (watchnum*4+16)));
  605         DBREG_DRX(d,watchnum) = 0;
  606         
  607         return (0);
  608 }
  609 
  610 
  611 int
  612 db_md_set_watchpoint(addr, size)
  613         db_expr_t addr;
  614         db_expr_t size;
  615 {
  616         int avail, wsize;
  617         int i;
  618         struct dbreg d;
  619         
  620         fill_dbregs(NULL, &d);
  621         
  622         avail = 0;
  623         for(i=0; i<4; i++) {
  624                 if ((d.dr[7] & (3 << (i*2))) == 0)
  625                         avail++;
  626         }
  627         
  628         if (avail*4 < size)
  629                 return (-1);
  630         
  631         for (i=0; i<4 && (size != 0); i++) {
  632                 if ((d.dr[7] & (3<<(i*2))) == 0) {
  633                         if (size > 4)
  634                                 wsize = 4;
  635                         else
  636                                 wsize = size;
  637                         if (wsize == 3)
  638                                 wsize++;
  639                         i386_set_watch(i, addr, wsize, 
  640                                        DBREG_DR7_WRONLY, &d);
  641                         addr += wsize;
  642                         size -= wsize;
  643                 }
  644         }
  645         
  646         set_dbregs(NULL, &d);
  647         
  648         return(0);
  649 }
  650 
  651 
  652 int
  653 db_md_clr_watchpoint(addr, size)
  654         db_expr_t addr;
  655         db_expr_t size;
  656 {
  657         int i;
  658         struct dbreg d;
  659 
  660         fill_dbregs(NULL, &d);
  661 
  662         for(i=0; i<4; i++) {
  663                 if (d.dr[7] & (3 << (i*2))) {
  664                         if ((DBREG_DRX((&d), i) >= addr) && 
  665                             (DBREG_DRX((&d), i) < addr+size))
  666                                 i386_clr_watch(i, &d);
  667                         
  668                 }
  669         }
  670         
  671         set_dbregs(NULL, &d);
  672         
  673         return(0);
  674 }
  675 
  676 
  677 static 
  678 char *
  679 watchtype_str(type)
  680         int type;
  681 {
  682         switch (type) {
  683                 case DBREG_DR7_EXEC   : return "execute";    break;
  684                 case DBREG_DR7_RDWR   : return "read/write"; break;
  685                 case DBREG_DR7_WRONLY : return "write";      break;
  686                 default               : return "invalid";    break;
  687         }
  688 }
  689 
  690 
  691 void
  692 db_md_list_watchpoints()
  693 {
  694         int i;
  695         struct dbreg d;
  696 
  697         fill_dbregs(NULL, &d);
  698 
  699         db_printf("\nhardware watchpoints:\n");
  700         db_printf("  watch    status        type  len     address\n");
  701         db_printf("  -----  --------  ----------  ---  ----------\n");
  702         for (i=0; i<4; i++) {
  703                 if (d.dr[7] & (0x03 << (i*2))) {
  704                         unsigned type, len;
  705                         type = (d.dr[7] >> (16+(i*4))) & 3;
  706                         len =  (d.dr[7] >> (16+(i*4)+2)) & 3;
  707                         db_printf("  %-5d  %-8s  %10s  %3d  0x%08x\n",
  708                                   i, "enabled", watchtype_str(type), 
  709                                   len+1, DBREG_DRX((&d),i));
  710                 }
  711                 else {
  712                         db_printf("  %-5d  disabled\n", i);
  713                 }
  714         }
  715         
  716         db_printf("\ndebug register values:\n");
  717         for (i=0; i<8; i++) {
  718                 db_printf("  dr%d 0x%08x\n", i, DBREG_DRX((&d),i));
  719         }
  720         db_printf("\n");
  721 }
  722 
  723 

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